The application of in situ and operando methods in catalysis – opportunities for UK-Africa collaboration through START

“When I saw the opportunity to be a part of a GCRF START team in the UK, I was very motivated to join the group. My aim is to make connections with people and be the link between researchers in Africa and groups in the UK which brings benefit to both. START has made my dream real; it has enabled something one can’t do by oneself because you need a team, and you need funding. There is no other better way to do our research than through the START collaboration.”

Dr Khaled Mohammed, University of Southampton, UK

Our team at the University of Southampton (UK) is focussed on the application of in situ and operando methods to all aspects of catalysis; this covers all areas of a catalyst’s “life-cycle” – from formation and operational behaviour, to eventually understanding what causes it to lose performance. A catalyst is a chemical substance widely used in large-scale chemical industry to enhance reactivity and selectivity towards target products of the reaction of interest without itself being consumed in the reaction.

However, the complex nature of such material requires an advanced tool to understand its behaviour under operating conditions fundamental to the chemical industry and in the drive to increase sustainability for the future of our planet. Extensive knowledge and experience in using synchrotron radiation sources is therefore vital to understand the complex nature of catalysts and to develop new technologies here in the UK and globally. Through the START collaboration, our knowledge and hands-on-experience in this area is shared with our African partners as they develop their own catalysis and synchrotron research programmes.

My name is Khaled Mohammed, and I am a Postdoctoral Research Fellow (PDRF) in Synchrotron Methods for Catalysis within Chemistry at the University of Southampton. Funded by the GCRF START grant, I joined START in October 2019 to work with Dr Peter Wells’ team – Peter is a GCRF START Co-Investigator (Co-I) and an Associate Professor within Chemistry at Southampton, holding a joint appointment with the UK’s national synchrotron, Diamond Light Source (Diamond). I joined the START project only a matter of months before the global COVID-19 pandemic and research has been challenging in this period. Despite this, I have contributed to several published studies[1] as a GCRF START PDRF.

Here I explain my perspectives on what START means as an African researcher in the UK.  My role involves contributing to British and international research, and I see myself as an ‘ambassador’ for my country (Egypt), making connections to people and being a link between researchers in the UK and those in other African countries.

GCRF START Postdoctoral Research Fellow, Dr Khaled Mohamed, preparing a wide range of materials including supported metal/metal oxides, and tailored porous framework architectures with well isolated active sites for directed catalysis at the University of Southampton. Photo credit: Khaled Mohammed. ©Diamond Light Source

Joining the START network at the University of Southampton, UK

My experience using such facilities, with particular emphasis on operando and time-resolved X-ray absorption fine structure spectroscopy (XAFS), dates back to my PhD studies at the University of Southampton (2010 – 2014) and my previous role as a Research Associate at University College London (2013 – 2015), where our group had the opportunity to use the facilities at the Research Complex at Harwell and the Beamline Allocated Group (BAG) at Diamond. In November 2015, I decided to go back to my home country, Egypt, to start a new academic role at Sohag University as a Lecturer in chemistry. I was very keen and motivated about the role with its many teaching activities. A few months later, however, I realised that my scientific research was limited in this role by the fact that there was no access to a synchrotron, which does not exist on the African continent.

On the bright side, however, I had the opportunity to speak with my colleagues in Egypt who have no experience in using such synchrotron tools and I could share with them the knowledge I had gained in the UK.  In addition, I could give lectures and seminars on the key questions about synchrotrons to the next generation of scientists: How does a synchrotron work?  What type of experiments do we do with synchrotrons? Which beamlines are available to use to support our research?

My colleagues in Egypt were excited about this subject, but it was also a challenge as the facilities are good but not good enough to do the level of advanced experiments / topics that one can do with synchrotrons. People are very motivated to do these advanced topics, such as characterisation of materials for catalysts and applications, but the problem is we do not have the funding or access to these kinds of experiments. Therefore, when I saw the opportunity to be a part of a START team, I was very motivated to join the group at Southampton.

GCRF START Postdoctoral Research Fellow, Dr Khaled Mohammed and GCRF START CO-I, Dr Peter Wells at the University of Southampton, UK. Photo Credit: Khaled Mohammed. ©Diamond Light Source

Catalysts and synchrotrons for renewable energy – the hydrogenation of furfural for biofuels

I was born in Sohag city, Egypt, where I lived for most of my childhood. I loved studying science at school, especially the physical sciences, and I dreamt about becoming a scientist to help provide power for the city where I lived – at that time access to electricity was very intermittent.  Outside the city, I wanted to help people who lived in the countryside where, at that time, there was no electricity at all. Later, my dreams shifted to chemistry and I was motivated and inspired to develop pharmaceuticals. I had seen my grandfather suffering with illness and die prematurely due to lack of available medicines.

Today, I find myself inspired by these experiences working in catalysis with applications in renewable energy where waste biomass is converted to liquid biofuels (Bioenergy), or waste CO2 is converted to high value chemicals that can be used in our daily life, or as an alternative to fossil fuels. These applications rely on catalysts but to make this process more sustainable and efficient, advanced techniques are required to understand how the catalysts work under operating conditions. It is a big challenge for African researchers to access the facilities and techniques needed for this type of work. Like my dreams when I was younger, I take great pride in trying to provide something useful to society. What I love about START is that it brings these dreams to reality.

A good example of the kind of research I have collaborated on is the hydrogenation of furfural. Furfural is a bio-derived molecule and can be converted to many useful products, including the generation of liquid fuels; it is therefore a renewable energy feedstock. However, bio-derived compounds are highly functionalised, this means they have many parts of the molecular structure that can undergo chemical change. Palladium (Pd) nanoparticles are widely used as an active component in furfural hydrogenation – a specific type of reaction that involves the addition of hydrogen to a compound – however, selectivity to specific products is a big challenge. In addition, Pd is a very scarce element and there are significant concerns about the sustainability of using such elements, both from an economic perspective and the environmental impact of mining such rare materials.

In our recent paper, [ACS Catal. 2020, 10(10), 5483–5492 (https://pubs.acs.org/doi/10.1021/acscatal.0c00414)], we demonstrated that a Pd/NiO catalyst can hydrogenate furfural using a dual site process; the Pd splits the H2 molecule into adsorbed hydrogen atoms onto the Pd surface, the adsorbed hydrogen then migrates onto the NiO surface where the furfural molecule is selectively transformed. For materials like this, we need to use advanced tools at Diamond Light Source, e.g. X-ray absorption spectroscopy, to understand more about our materials and their unique properties that allow them to function as catalysts.

GCRF START Postdoctoral Research Fellow, Dr Khaled Mohammed, at the University of Southampton, UK. Photo Credit: Khaled Mohammed ©Diamond Light Source

In the shadow of the Covid-19 pandemic – facilitating UK-African research through cross-disciplinary teamwork

“START has and continues to be a fantastic opportunity for the UK to work in concert with our African partners. Our futures are intertwined; we share the same global challenge of treading more lightly on our planet, be it to mitigate climate change or to preserve our natural world, whilst simultaneously sustaining our growing populations. New functional materials are needed to underpin the emerging sustainable technologies that allow us to tackle these challenges and START is an important gateway for sharing the tools and expertise to accelerate these advances.”

Dr Peter Wells, University of Southampton, UK

During the pandemic, the GCRF START grant has enabled us to stay productive and self-motivated, for which we are truly grateful. Although access to laboratory and synchrotron facilities has been limited, we have been able to continue our work remotely. We set goals including research activities, data reduction/analysis and submitting new beamline proposals. In addition, we participated in many on-line activities including workshops, seminars, and social activities with all participants in START.  

The environment in the group here at Southampton has been excellent. There are things you can’t just learn by talking; we have learnt by doing research-based experiments together. Peter has taught me a lot. If I do an experiment, I give the idea to Peter, and then we do some tests to validate which beamline to use and what we need to adjust and optimise before we go ahead.

When I was in Egypt – before I got involved in START – I tried to do collaborations with people here in the UK.  I could do the basics and prepare materials, but I couldn’t correlate the structure-performance relationship without beamtime experiments. Being here in the UK, interacting with experienced scientists, has enabled me to see what is new and to push things forward through START, sharing what I learn with my African colleagues.

A great achievement has been international collaborations across a range of disciplines. After joining START in 2019, I found the group already working with Professor Michael Claeys’ Group at the University of Cape Town (UCT) in South Africa. I soon got involved in this project working with Dr Mohamed Fadlalla and Chris Mullins on research using the B18 beamline at Diamond to assess, in situ, the effect of substituents in ferrite structure with the general formula of AB2O4. These are used in a wide range of catalytic reactions including the Haber-Bosch process, water-gas shift reaction, dehydrogenation of ethylbenzene, and Fischer-Tropsch synthesis (FTS) to produce liquid hydrocarbons/fuels.

I was able to assist Mohamed with his experiment in December 2020. We had to submit a proposal and get it accepted (to do this you have to submit initial results like a proof of concept). Once accepted, the experiment had to be done in a specific time frame. But before Mohamed came over to the UK to conduct the experiment, tests had to be carried out for optimisation of the materials. This takes time so I did this first to ensure the experiment ran smoothly when he arrived.  

There are lots of other things that must be organised and managed before experiments like these, therefore my role has been to optimise as much as possible to increase the chance of success. Since then, we have assisted Mohamed and his colleagues in data analysis for publication. This successful beamtime experiment motivated us to explore new ideas, for example, in making catalysts with well-isolated active sites – mainly cobalt in tetrahedron sites to be used in preferential oxidation of carbon monoxide.

GCRF START Co-I, Professor Michael Claeys (L) and Research Officer, Dr Mohamed Fadlalla (R), at the University of Cape Town’s Centre for Catalysis, South Africa. Photo credit: Rebekka Stredwick. ©Diamond Light Source.

The future with START – ‘follow on’ opportunities for UK and African energy materials research

“START is a fantastic opportunity for the UK to work in concert with our African partners to tackle shared challenges. It is clear that the excitement generated can be inspirational and helps to further integrate research partnerships.”  – Dr Peter Wells, University of Southampton, UK

We are discussing our new research ideas going forward with Mohamed and another colleague of his, GCRF START Postdoc – Dr Thulani Nyathi – and have set goals and tasks for two ‘follow-on’ projects currently in the pipeline. As a result, I am in the process of sending some samples to Mohamed and Thulani for the preferential oxidation of carbon monoxide. This research has the dual benefit of reducing the harmful effects of carbon monoxide and using the carbon monoxide captured to make useful chemicals for energy, such as fuel cell storage to power vehicles and other devices.

We are also very impressed with the facilities and equipment at UCT, some of which we don’t have here in the UK, and which could be beneficial to access in the future. On a practical level, routine visits are important for hands-on experience (sadly due to the Covid-19 pandemic my visit to UCT in 2020 was cancelled), therefore continuing remote options in the meantime is vital for sharing ideas.

GCRF START Postdoctoral Research Fellow, Dr Khaled Mohammed, next to the vertical stainless-steel temperature-programmed reactor at the University of Southampton (UK) with temperature-programmed controller for conducting solid-gas phase catalytic reactions under different conditions up to 1500C. Photo Credit: Khaled Mohammed ©Diamond Light Source

Perspectives from our collaborators in South Africa on the impact of START

Here I want to share testimonials from Dr Thulani Nyathi and Dr Mohamed Fadlalla demonstrating their perspectives on our UK-Africa collaborations.

Thulani said,

“I first worked with Dr Peter Wells’ group prior to the GCRF START programme through a collaboration also involving the UK Catalysis Hub (located on the Harwell Science and Innovation Campus in Oxfordshire) and with Dr Emma Gibson’s group in Chemistry at the University of Glasgow, funded by the EPSRC (grant EP/R026815/1). This included my first visit to a synchrotron facility – Diamond Light Source – and my first exposure to two in situ techniques, XAS and DRIFTS, which were used to study supported cobalt oxide catalysts for the preferential oxidation of carbon monoxide (CO-PrOx).

This collaboration proved to be highly successful as it was concluded with a very good publication[2] in ACS Catalysis in 2019. Through the GCRF START programme (grant ST/R002754/1), I have continued to work with Peter’s group and Emma’s group, using the Block Allocation Group sessions administered by the UK Catalysis Hub, to analyse fresh and spent catalysts for the CO-PrOx reaction. I was then able to conclude my PhD thesis in September 2020 and publish a second paper in Applied Catalysis B: Environmental in June 2021[3].

There exists on-going work between the Southampton and UCT groups where we try to study substituted iron oxide and alloy catalysts for use in the hydrogenation of carbon dioxide (a greenhouse gas) to value-added chemicals. This work has already involved a trip to Diamond in 2019 and the results obtained will feature in a paper we aim to publish later in 2021. I hope to make more trips to Diamond and to continue working with the Southampton and Glasgow groups in the upcoming years.”

GCRF START Postdoctoral Research Fellow, Dr Thulani Nyathi from the University of Cape Town’s Centre for Catalysis, South Africa. Photo Credit: Linda Vos. © http://www.lindavos.co.za

Mohamed said,

“The highly seamless collaboration with Dr Peter Wells and Dr Khaled Mohammed from the University of Southampton has led to a more profound collective understanding of the catalytic materials under activation and under working conditions using in situ and ex situ synchrotron-based techniques. Owing to the successful and harmonious collaboration between the two research groups thus far, further partnership is in the works to investigate catalyst structure/activity/selectivity correlations in the energy material field.”

Dr Mohamed Fadlalla at the University of Cape Town’s Centre for Catalysis in South Africa conducting analysis of the CO2 hydrogenation over iron-based alloys via two-dimensional gas chromatography x gas chromatography (2D GC x GC). Photo credit: Rebekka Stredwick © Diamond Light Source

START’s achievements and the future – “a great work for great value”

When I look back at what has been achieved and then look forward to the future, I ask myself the question: If there wasn’t a START network/project, how would people who don’t know about synchrotron techniques know about these opportunities? START not only transfers knowledge and enhances capacity, but it also builds awareness a bit like an advertisement. It helps us know where and how to apply to synchrotrons like Diamond for beamtime and shows us what is possible and how to do the experiments in the right way. And synchrotron techniques give unprecedented insights essential for our research. If there hadn’t been a GCRF START grant to fund these possibilities, it would have delayed our research because collaborations like START boost and speed up the process and findings.

In Africa we need the fundamental facilities to train the next generation ready to use synchrotrons. More locally, in Egypt, we need capacity-building facilities to do initial experiments and fundamental research. For example, a catalytic reactor would be very useful for scientists to do some reactions. We can do the preparation – we can buy the chemicals – but to do the catalytic reactions we need a reactor where we can do the experiments in optimised conditions.

We also need a ‘Centre for Catalysis’ in Egypt where we can teach the new generation to develop sufficient skills to collaborate with the UK and other countries for advanced experiments and push the research forward. If research hubs could be set up across Africa, like the Catalysis labs at UCT, this would be fantastic and START could be an ideal vehicle to make this happen. Another route is through funding agencies like the British Council/Newton Funding which provide travel grants and other support for researchers in developing countries. 

To summarise the achievements of the GCRF START grant and what START means to me: I would describe it as “a great work for great value”, and all this despite massive setbacks caused by the Covid-19 pandemic.

START does great work that allows scientists from developing countries to gain knowledge and experience from leading scientists in the UK and to reciprocate, as my role shows. It does great work because it offers opportunities for us to work with scientists from all over the world on a level playing field. Ultimately, the greatest value from my perspective is that we work hard to provide (in a sustainable way) energy/electricity, medicines and many other applications for people who don’t have these fundamental things, enabling a better life for the future – what value is bigger or better than this?

Read more about the UN’s Sustainable Development Goals here

GCRF START Postdoctoral Research Fellow, Dr Khaled Mohammed, engaged in quantification and identification of reaction products using the GC (FID & TCD detectors) equipment at the University of Southampton, UK. Photo credit: Khaled Mohammed. ©Diamond Light Source

[1] [1] ACS Catal. 2020, 10(10), 5483–5492 (https://pubs.acs.org/doi/10.1021/acscatal.0c00414) – This work has significant implications for the upgrading of bioderived feedstocks, suggesting alternative ways for promoting selective transformations and reducing the reliance on precious metals. [2] Phys. Chem. Chem. Phys., 2020,22, 18774-18787 (https://pubs.rsc.org/en/content/articlelanding/2020/CP/D0CP00793E#!divAbstract) – This study demonstrates the complexity of mechanochemically prepared materials and through careful choice of characterisation methods how their properties can be understood. Synchrotron techniques, such as X-ray absorption spectroscopy (XAS), have multiple benefits, which aid the in-depth understanding of chemically important yet complex systems. [3] Nanoscale Adv., 2019,1, 2546-2552 (https://pubs.rsc.org/en/content/articlelanding/2019/NA/C9NA00159J#!divAbstract) –  Using state-of-the-art beamlines, this study demonstrates how X-ray absorption fine structure (XAFS) techniques are now able to provide accurate structural information on nano-sized colloidal Au solutions at μM concentrations. 

[2] ACS Catal. 2019, 9, 8, 7166–7178, Publication Date: June 28, 2019 https://doi.org/10.1021/acscatal.9b00685. Copyright © 2019 American Chemical Society

[3]  Author: Thulani M. Nyathi, Mohamed I. Fadlalla, Nico Fischer, Andrew P.E. York, Ezra J. Olivier, Emma K. Gibson, Peter P. Wells, Michael Claeys. Publication: Applied Catalysis B: Environmental. Publisher: Elsevier. Date: 15 November 2021. https://doi.org/10.1016/j.apcatb.2021.120450

Development and optimisation of thin-film photovoltaic devices (solar cells) for sustainable solar energy

Scientists in the UK’s University of Sheffield’s Electronic and Photonic Molecular Materials Group (EPMM) work on the development and optimisation of thin-film photovoltaic devices (solar cells) for sustainable energy solutions. The advantage of these type of devices is that they can convert sunlight to electrical power with high efficiency, with such materials being easy and cheap to process, potentially allowing ‘sustainable’ solar cells to be manufactured at high volume and low cost. This is important given the rising global energy demand and need for electrification in remote, rural areas, particularly in Africa, where national grids are often over-constrained.

The EPMM Group, which collaborates with the GCRF START grant, focuses on two classes of materials: perovskites[1], [2] and polymer fullerene blends. Industry standard silicon solar cells require very high temperature processing and expensive controlled environments (clean rooms) for their manufacture, whereas hybrid-perovskites solar can be fabricated at low temperatures using liquid-based processing which reduces costs and makes their production easily scalable. However, one of the biggest challenges with these hybrid-perovskites is their reduced stability compared to silicon. The Group is therefore investigating these materials to understand how best they can be optimised for the next generation of solar energy devices.

Fig 1. This figure shows both small and large area perovskite PV devices fabricated by spray coating. The figure also shows a SEM cross-sectional image through a typical device. Part (a) shows a photograph of small and large-area fully spray-coated perovskite solar cells. Parts (b,c) show a cross-sectional SEM image of complete devices incorporating a spray-cast perovskite layer. The device in part (b) utilises spin cast SnO2 and spiro-OMeTAD layers whereas the device in part (c) is fully spray-coated. Source: Bishop, J.E., Read, C.D., Smith, J.A. et al. Fully Spray-Coated Triple-Cation Perovskite Solar Cells. Sci Rep 10, 6610 (2020). https://doi.org/10.1038/s41598-020-63674-5.

Investigating affordable energy solutions with the GCRF START grant

In their research, the EPMM scientists have benefitted from the GCRF START grant, enabling them to get involved in new international collaborations as well as access the UK’s national synchrotron, Diamond Light Source (Diamond), where they use synchrotron techniques such as X-ray scattering to research halide perovskites, a potential material for the next generation of low-cost photovoltaics.

“Using Diamond allows us to explore the structure of these materials at length-scales corresponding to atomic and molecular bonds, we have found that understanding the structure of these materials is absolutely critical in developing our understanding of how they ‘work’ in devices. Ultimately, this understanding helps in developing new materials or new ways to process existing materials to get optimum performance (efficiency) out of our solar cells.”

Prof. David Lidzey, GCRF START Co-I and Director of the EPMM Group
From left to right: Adam Shnier from the Energy Materials Research Group at the University of the Witwatersrand, South Africa, and Rachel Kilbride, Joel Smith and Mary O’Kane from the Electronic and Photonic Molecular Materials Group at the University of Sheffield, UK. The scientists are conducting wide-angle X-ray scattering measurements at the UK’s national synchrotron Diamond Light Source (Diamond). The students are using one of Diamond’s 2D X-ray detectors to monitor in-situ crystallisation and degradation processes with perovskite thin film samples held in an environmental chamber. Photo credit: Onkar Game. ©University of Sheffield / EPMM Group

The GCRF START grant has also funded Dr Onkar Game’s one-year Postdoctoral position in the EPMM Group during which time he has both undertaken his own experiments on perovskites and worked very closely with various PhD students in the Group. Prof. Lidzey reports that Dr Game’s input has been invaluable, this flexible work-pattern maximising the amount of research using the funding available.

“The GCRF START grant provided me a unique opportunity to make use of world class structural characterisation facilities at Diamond” says Dr Game. “Working with PhD student Joel Smith, we utilised the in-situ Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) facility at the I22 beamline in Diamond to identify the factors affecting the degradation of perovskite crystal commonly used in perovskite-PV devices[3]. This helped us to tune the composition of perovskite crystal to make it more stable towards moisture and light induced degradation. I also enjoyed setting up the in-situ measurements with Joel on understanding of solvent-induced liquification and crystallisation of perovskite using GIWAXS on Diamond’s I07 beamline,” Dr Game adds.  

From left to right: Prof. David Lidzey and Dr Onkar Game from the University of Sheffield’s EPMM Group, UK. The scientists are investigating perovskite degradation using an environmental chamber and 2D X-ray detector on the I07 beamline at the UK’s national synchrotron Diamond Light Source. Photo credit: Joel Smith. ©University of Sheffield / EPMM Group

Collaborative research on Perovskites: the effects of composition and temperature

Dr Claire Greenland completed her PhD in the EPMM Group supervised by Prof. Lidzey. She has been working on perovskites and has been particularly interested in how the structure of such materials are affected by their composition and local temperature. This work was done in close collaboration through the GCRF START network with the Energy Materials Research Group at the University of the Witwatersrand (Wits), South Africa, led by GCRF START Co-I, Prof. Dave Billing. In this research, Claire studied one type of popular perovskite called a ‘mixed cation’ perovskite, and used X-ray scattering to characterise the structure of the perovskite as it was cooled down to very low temperature (-190 °C). She also measured the ability of the perovskite to absorb and emit light over the same temperature range. In these studies, Claire was looking for changes in the crystal-phase as the temperature was changed.

Understanding such processes is important, as the temperature at which some phase changes occur are within the expected operational temperature of the solar cell and understanding the effect on the properties of the materials in the solar cell forms a critical part of the understanding of how such materials (and devices) work.

“Interestingly, the structure of the perovskite crystal is not fixed, but can vary as a function of temperature, being ‘cubic’ at room temperature and starting to change to a ‘tetragonal’ phase around -13 °C, with a second low-temperature phase identified at -180 °C,” Prof. Lidzey explains. “Through careful analysis, these changes in crystal structure could be correlated with changes in the optical properties of the perovskite.”

This research was supported with assistance from Wits University scientist, Adam Shnier. Adam met members of the Sheffield team at a GCRF START meeting in 2018, hosted by the Energy Materials Research Group at Wits.

“Adam Shnier provided us invaluable support in the analysis of the X-ray scattering data, allowing us to understand how the crystal structure changed with temperature,” Prof. Lidzey says.With support from the GCRF START grant, Adam was able to travel to the UK in 2019 and assist us in some scattering experiments performed at Diamond and became an important part of the team.”  

“At the 2018 GCRF START meeting, I met a PhD student, Joel Smith, from the University of Sheffield who works on the same type of materials,” says Adam. “Joel and his colleagues are experienced at making high quality, efficient devices; while at Wits, we are experienced in making other materials that can be used for these devices and studying their crystal structures. As the 2019 GCRF START meeting was being held in the UK, we planned a research visit where I would spend a week working with Joel and his colleague Dr Onkar Game in Prof. David Lidzey’s laboratory at Sheffield. The purpose was to share technical knowledge. They were more than happy to share their experiences with these materials which instilled me with a plenty of ideas and information to share with my colleagues at home in South Africa.”

Adam Shnier from the Energy Materials Research Group at the University of the Witwatersrand, South Africa, visiting the UK’s national synchrotron, Diamond Light Source. Photo credit: Joel Smith. ©University of Sheffield / EPMM Group

The research was published in January 2020[4] and formed a very important part of Claire’s PhD thesis. Claire has since passed her PhD viva and has come back to Sheffield in the position of ‘University teacher’. While she is not currently working on perovskites, her knowledge of materials physics and experience in understanding complex phenomena are proving invaluable in teaching electromagnetism to 1st year undergraduate students and will also be useful in the 2nd year lab experiments that she is developing and running, says Prof. Lidzey.

‘The GCRF START collaboration enabled me to collaborate with academics from Wits University in South Africa, which greatly enriched my work due to their expertise in X-ray diffraction and crystal structure,” Claire explains.  “I collaborated mainly with Adam Shnier, who was able to computationally model the X-ray diffraction data taken at a range of temperatures on mixed cation perovskites. This modelling revealed the temperature dependence of a variety of crystal parameters, which not only allowed us to identify phase transitions in these materials but also to correlate crystal structure with photoluminescence properties.”

“I really enjoyed working with Adam, and his insight on all things related to crystal structure and phase was invaluable to my work,” Claire adds. “These studies shed light on the fundamental properties of perovskites and how these vary as a function of temperature – such studies are a key part of solar cell optimisation, because real world solar cells must operate under a wide range of temperatures. So, it’s really cool to know that this project was part of the push towards cheap and efficient solar cell materials, which are an essential part of tackling climate change.”  

Dr Claire Greenland from the University of Sheffield’s Electronic and Photonic Molecular Materials Group, UK. ©University of Sheffield / EPMM Group

Perovskite ‘healing’ for high-speed manufacture processes

PhD student Joel Smith has also been working on perovskites. Here, however, he has been interested perovskite recrystallisation processes using solvent molecules. In this process, a perovskite film is exposed to a solvent gas, with this exposure causing the solid perovskite film to melt into a different solid or liquid form. Once the gas is removed or when heated, this material crystallises back into a ‘healed’ perovskite. The advantage of this process is that the quality of the perovskite film can be substantially improved. Practically, this could be used to improve the quality of perovskite films deposited in a high-speed manufacture process such as spray coating.

The first part of this work was led by Dr Onkar Game and investigated how treatment with one type of solvent had some unexpected effects on the perovskite film microstructure. This included measurements on thin films at Diamond to understand how these changes in microstructure affected the perovskite’s ability to withstand different challenging environments3. As part of his PhD, Joel undertook experiments at Diamond where he used X-ray scattering to monitor the very rapid changes in the structure of the perovskite film as it turned into a liquid and then back into the perovskite.

“Here we were able to resolve crystal structures of new intermediate compounds that formed in the liquid, and we could evidence the improvement in crystal structure caused by the healing process,” explains Prof. Lidzey, “Importantly, we also showed that this process could be enhanced by changing the temperature at which healing took place.”

Joel is currently writing a paper on this work which has formed part of his PhD thesis. He is set to start his Postdoctoral research in Prof. Henry Snaith’s group at the University of Oxford, working on advanced perovskite solar cell devices.

“Bringing together expertise from our different institutions in the UK and Africa through collaborating with the GCRF START grant has allowed us to investigate the crystallisation behaviour and stability of perovskites in new ways at Diamond Light Source,” says Joel. “More generally, we have been able to assist each other in fabricating, characterising and understanding these materials by sharing experience and facilities. The wider START community has been valuable as a mutually supportive network for us to develop as independent researchers, and most importantly, to grow the synchrotron research community in Africa.”

Joel Smith from the University of Sheffield’s Electronic and Photonic Molecular Materials Group, UK. Photo credit: Onkar Game. ©University of Sheffield / EPMM Group

Commenting on the need for affordable, renewable energy solutions in Africa and the importance of collaboration to tackle global energy challenges, Prof. Billing said,

The synergy in GCRF START collaborations of having people from different backgrounds tackle a problem makes the solution more robust. Creativity is important to most Africans, and we need to be involved in these creative solutions. Also, if you co-develop through collaboration, you have a sense of ownership which is what we set out to do through the GCRF START grant.”

“Everything costs energy, fundamentally,” Prof. Billing adds. “Silicon uses a lot of energy in its making to make solar cells so I think the best we can do as humans is look at remediation and balance. The GCRF START grant asks us to consider questions in our research around the global challenges like: am I using components that are sustainable? Are we using elements which are abundant, affordable, and environmentally compatible? If you think about a rural village which is cooking using wood charcoal, they are energy poor and lighting will be paraffin or candles. If you can find a cheap source of energy there and you can bring in lighting, that is life changing!”

Traditional rondavel house in a rural South African village. Photo Credit: Rebekka Stredwick. ©Diamond Light Source
Adam Shnier at the University of the Witwatersrand taken in front of a Bruker D8 diffractometer which he uses in the analysis of thin film materials. Photo credit: Adam Shnier. ©Diamond Light Source

Read more about the Sustainable Development Goals for Energy (SDG 7).


[1] Here, “perovskite” is a name for a class of crystalline material, and there are many different combinations of starting materials that can be used to make a perovskite. Some of these materials absorb sunlight more efficiently, and others have greater environmental stability (both important characteristics for practical applications of solar cells).

[2] Bishop, J.E., Read, C.D., Smith, J.A. et al. Fully Spray-Coated Triple-Cation Perovskite Solar Cells. Sci Rep 10, 6610 (2020). https://doi.org/10.1038/s41598-020-63674-5. This work demonstrates the possibility for spray-coating to fabricate high efficiency and low-cost perovskite solar cells at speed.

[3] Onkar S. Game, Joel A. Smith et al.  Solvent vapour annealing of methylammonium lead halide perovskite: what’s the catch? J. Mater. Chem. A, 8, 2020, 10943-10956 DOI: 10.1039/D0TA03023F 

[4] Greenland, Claire, Adam Shnier, Sai K. Rajendran, Joel A. Smith, Onkar S. Game, Daniel Wamwangi, Graham A. Turnbull, Ifor DW Samuel, David G. Billing, and David G. Lidzey. “Correlating Phase Behavior with Photophysical Properties in Mixed‐Cation Mixed‐Halide Perovskite Thin Films.” Advanced Energy Materials 10, no. 4 (2020): 1901350 (https://doi.org/10.1002/aenm.201901350)

Breaking barriers and aiming high! An African woman in Energy Materials Science – Gugulethu Nkala’s story

Hard work, dedication and endless opportunities, I can now say I am on the path to previously unimaginable goals. A dream come true! We are breaking the barriers that make Science seem unattainable, by being the link between Science and society, made possible by funding bodies like the GCRF START grant.”

Gugulethu Nkala, PhD student in the Energy Materials Research Group at the University of the Witwatersrand, South Africa.

Gugulethu Charmaine Nkala is a PhD student at the School of Chemistry in the Energy Materials Research Group at the University of the Witwatersrand (Wits), South Africa. From Roodepoort, west of Johannesburg, she is the eldest of three daughters, descending, she says, “from a line of great women, whose circumstances did not allow them to proceed to higher education”. Gugu’s great grandmother had to leave school at grade 7 (after she finished primary school) because as a woman it was only seen necessary to be able to write and read letters; Gugu’s maternal gogo (grandmother) was a domestic worker, and her parents were not able to study beyond high school. Gugu says, therefore, “It is with this in my heart, that I have been encouraged to go forth and reach places that their hopes and dreams could not take them. I have a story to tell, a story to finish.” Gugu is determined to share her story and be a role model to motivate women and girls to take up science.

Gugu’s research focuses on improving renewable energy storage systems to make them more efficient, affordable, safe and environmentally friendly in order to address the energy poverty gap in Africa, in line with the UN’s Sustainable Development Goals. Under the PhD supervision of GCRF START grant Co-I, Professor Dave Billing[1], Prof Caren Billing[2] and Dr Roy Forbes, her particular interest is: ‘The Use of Fused Bimetal Phosphate-based Ceramics for Solid-State Electrolyte Applications’[3], through which she investigates batteries as energy storage devices for applications such as phones and tablets, with the aim of fabricating a solid-state electrolyte that can be used in an all-solid-state battery (a battery in which the electrodes and electrolyte are solid).  

It is with the GCRF START grant, that Gugu has been able to visit the UK’s national synchrotron, Diamond Light Source (Diamond), and has also attended START related workshops and meetings which have furthered her research knowledge and skills, introducing her to international collaborations and research networks overseas and in Africa – experiences Gugu describes as “beyond invaluable in my studies” and a “privilege”.  In the next few weeks, some of Gugu’s research materials are set for analysis using X-ray Absorption Spectroscopy (XAS) techniques on the B18 beamline at Diamond as part of a Beamtime Allocation Group (BAG).

Energy Materials scientist, Gugulethu Nkala, PhD student at the University of the Witwatersrand, South Africa. Photo credit: Gugulethu Nkala. ©Diamond Light Source

Gugu is the first in her family to go to university, an achievement she attributes to the culture of her school and the support of her parents who invested in their children’s school education, leading her to become one of the top pupils in her school and developing her love of STEM.

“My grandmother encouraged my father to enable the education of the ‘girl-children’ in our family,” Gugu explains, “and I was interested in the physical sciences in particular – physics, chemistry, biology – subjects not many girls go for. From an early age I was inquisitive, and my parents nurtured that side and were engaging and supportive. This was formative, coupled with the school I went to which instilled discipline, resilience and, above all else, ‘the spirit of chasing one’s greatness’.”

Gugu’s aunt assisted with university fees in Gugu’s first year when Gugu’s father was retrenched as a machine minder in 2012, and what followed is a journey of tenacity and resilience into the world of energy materials science – an unusual career-path for a woman in Africa. Through bursaries and working hard in her vacations to fund her studies, despite various setbacks, Gugu has been able to accomplish her dreams and achieve great things. Testament to her hard work, she has received various awards and is now studying for her PhD, receiving mentorship from her supervisors and mentors, Prof. Caren Billing and Prof. Dave Billing and funded by a bursary.

“I was sold at an early stage on material science – I fell in love with it! Being part of Prof Dave Billing’s group helped me to look at things from different perspectives,” Gugu enthuses.

Gugu loves working with the Energy Research Group at Wits and collaborating with the GCRF START grant because she is encouraged to dream big and believe what some might seem is impossible to achieve for a young woman in Africa.

Earlier in my academic career, I dreamed of being the head of a Research and Development department in South Africa. However, being in my research group with the teachings and mentoring of my supervisors has shown me that I can aim higher, dream the once impossible,” she explains.  

Energy materials PhD student, Gugulethu Nkala, on a workshop tour of UK’s national synchrotron, Diamond Light Source (Diamond), in March 2020. Here Gugu is looking at the large red magnets that are part of the linear accelerator at Diamond. The electron beams travel through the linear accelerator and are used to investigate the samples provided by the scientists for their experiments. Photo credit: Gugulethu Nkala. ©Diamond Light Source

Closing the energy poverty gap in sub-Saharan Africa

Gugu’s motivation behind her research project comes from the desire to find solutions to energy challenges in sub-Saharan Africa, starting in South Africa where a large population, especially in the rural areas, is still without access to basic commodities such as electricity, sanitation and health care, something that particularly impacts women. In these parts, firewood is still the most used source of energy for cooking, as well as paraffin lamps and candles for lighting[4]. Approximately 80% of South Africa’s electricity relies on coal, with the resulting environmental challenges that this brings[5]. Shifting the focus towards improving renewable storage systems (such as solar, wind, hydrology, and others) would be beneficial, not only to the planet but to the health and livelihoods of human populations.

In order to bring renewable energy sources into the energy mix, the focus of scientific research needs to be moved towards improving renewable storage systems such as batteries. The most widely used rechargeable batteries contain toxic electrolytes such as sulfuric acid in lead acid batteries and lithium perchlorate in lithium-ion (Li-ion) batteries. The drawbacks of current Li-ion batteries are, amongst others, their costs and reliability concerns, which are attributed to the deterioration of battery devices over relatively short periods of time. The constant replacement of these materials has a negative impact on the environment[6].

Commercial batteries use an organic liquid as an electrolyte and these organics compromise the safety of the battery[7]. Increasingly, alternative electrolyte materials have received great attention, more specifically solid-state electrolytes[8]. The use of solid-state electrolytes would eliminate the need for a separator, avoiding the use of organic electrolytes and therefore the use of safer batteries that do not pose any leakage risks[9].

In Gugu’s studies, she is working on a material based on the sodium (Na) superionic conductor (NASICON) structure type, namely lithium titanium phosphate LiTi2(PO4)3 (LTP). This involves investigating its properties as a potential material for a solid-state electrolyte in Li-ion batteries to address the challenges that arise from current batteries. Gugu’s research includes understanding the Li-ion conductivity of the class of materials being studied under different environmental conditions such as temperature, and how the materials behave in different atmospheres, specifically air and nitrogen, an inert atmosphere. The research also involves exploring ways in which lower cost batteries can be synthesised.

Breaking down barriers and giving back to the community – being a role model

Gugu’s involvement in university science outreach projects to schools has focussed on educating learners and teachers from different backgrounds about the importance of renewable energies. Organised through the Energy Materials Group, Gugu is enthusiastic about motivating and assisting young people from disadvantaged backgrounds to fulfil their dreams in the way she herself was encouraged from a young age to fulfil her goals.  This is also a way for Gugu to give back to the community, as well as learn about community-based perspectives and how the Group’s research might impact everyday lives.

“Most of these children come from impoverished backgrounds and do not have role models in their society who they can look up to, to enable them to see that their dreams are not so far out of reach, and that their circumstances do not have to be a tight leash that keep them away from dreaming bigger,” Gugu explains. “Seeing a black girl in science, makes them see that there is someone, just like them, who has gone this far. We are breaking barriers that makes science seem unattainable, by being the link between science and society, made possible by funding bodies like the GCRF START grant.”

One of the outreach science demonstrations was a solar panel station where people could charge their phones. This enabled the scientists to explain the science behind solar panels, as Gugu describes below,

“The students were excited and astonished by the fact that one can use the sun to power their devices. Seeing their reactions and being part of something so special made me come back with the understanding of just how deep our impact in society could be, educating one child at a time.”

Energy materials PhD student, Gugulethu Nkala, at a University of the Witwatersrand’s science outreach event in South Africa.
Photo credit: Gugulethu Nkala. ©Diamond Light Source

Attending ANSDAC workshops in Africa and visiting Diamond Light Source in the UK

 In 2018, Gugu attended the first African Neutron and Synchrotron Data Analysis Competency workshop (ANSDAC), where the GCRF START grant is amongst the funding bodies. This workshop focuses on teaching African scientists about synchrotron techniques and how to analyse the results obtained, bringing in experts in different field techniques to ensure the best teaching possible. The students not only learn about synchrotron science but also how to analyse the data. Gugu also took an online course through Brookhaven Laboratory in the USA, which, she says, “forced us to push ourselves and the boundaries of science, making the best of whatever resources we had.”

From the 10-12 March 2020, just before the Covid-19 pandemic lockdown, Gugu was one of the attendees of the XAS workshop hosted and taught at Diamond on the Harwell Campus, the UK’s world-class innovation hub.  

“Visiting Diamond in the UK was a life changing opportunity,” Gugu enthuses. “It took me from a position of remotely learning about synchrotrons and taking virtual tours, to experiencing this first-hand.”

“You read about it in textbooks,” she continues “and then I was standing in front of it and there was a glorious opportunity to take a tour inside the facility. One of the topics we covered at the ANSDAC workshop was XAS, so I already had a good basis for the workshop at Diamond. This background knowledge allowed me to learn more about the technique and the data analysis, starting from a position of knowledge, once again, enabled by the GCRF START grant. It was wonderful to consult the beamline scientists and do hands on tutorials; to be in the same room as the people one looks up to.”

Not only has the GCRF START grant enabled Gugu to visit the synchrotron of her dreams, but it has also fundamentally impacted her skills and abilities, and her perspectives on her future career path. Visiting Diamond, Gugu says, has shown her new horizons of learning which she wants to bring back to the science community in Africa.

“The GCRF START grant has enabled me to move forward from attending online courses by Brookhaven National Laboratories (Applications of Synchrotron and Electron-Based Techniques 2018) to actually running X-ray diffraction (XRD) – an analytical method used to determine the nature of crystalline materials – and atomic Pair Distribution Function experiments – an X-ray scattering technique that can be used to study the local structure of materials at the atomic scale,” explains Gugu. “This brings results that take us students closer to answering the fundamental questions in our projects, sharpening our focus and skills to work out what steps to take next in the future.”

 Another goal achieved, she says, would be the opportunity to take up a postdoctoral position and work alongside beamline scientists at Diamond on X-ray Absorption Spectroscopy.

Achieving this goal,” Gugu says, “would be the completion, or the start of my story, of my grandmothers’ stories. The story of Black Girl Magic!”

Energy materials PhD student, Gugulethu Nkala, from the University of the Witwatersrand, South Africa, on a visit to the UK’s national synchrotron Diamond Light Source.
Photo credit: Gugulethu Nkala. ©Diamond Light Source

With the ongoing Covid-19 pandemic in 2020 and 2021, Gugu and her peers are thankful for the support of their supervisors, despite the challenges and delays that lockdowns and restrictions have brought, such as restricted access to campus to undertake experiments and having to book precious time slots to use laboratories.

“Our supervisors have been checking in on us regularly, encouraging us and helping us not to panic. They have been going above and beyond to try to ensure we have the software to process our data. This has been pretty amazing support,” Gugu reports.

Commenting on Gugu’s progress and ambitions, Prof Caren Billing says, “Gugu got back from attending an XAS training workshop at Diamond Light Source the week before our airports were closed due to the Covid-19 pandemic (March 2020). The visit to Diamond through the GCRF START grant has raised her expectations of herself and her work to new levels. She has been presenting talks at our group meetings to inform others of what she has learnt and brought a great amount of enthusiasm with her.”

Energy Materials PhD student, Gugulethu Nkala, with the GCRF START banner at the University of the Witwatersrand, South Africa. Photo credit: Gugulethu Nkala. ©Diamond Light Source

[1] Prof Dave Billing is Professor in the School of Chemistry and Co-PI of the Energy Materials Research Group at the University of the Witwatersrand (Wits), South Africa, and also Assistant Dean in the Faculty of Science at Wits.

[2] Prof Caren Billing is Associate Professor in the School of Chemistry at the University of the Witwatersrand, South Africa

[3] The support of the DST-NRF Centre of Excellence in Strong Materials (CoE- SM) towards this research is hereby acknowledged. Opinions expressed and conclusions arrived at, are those of the author and are not necessarily to be attributed to the CoE- SM.

[4] Eberhard, A., Leigland, J. and Kolker, J., 2014. South Africa’s Renewable Energy IPP Procurement Program. World Bank Publications. (https://ppp.worldbank.org/public-private-partnership/library/south-africa-s-renewable-energy-ipp-procurement-program-success-factors-and-lessons-0)

Banks, D. and Schäffler, J., 2005. The potential contribution of renewable energy in South Africa. Sustainable Energy & Climate Change Project (SECCP). ( https://www.ee.co.za/wp-content/uploads/legacy/Gener%201.pdf )

Fluri, T.P., 2009. The potential of concentrating solar power in South Africa. Energy Policy37(12),pp.5075-5080. (https://econpapers.repec.org/article/eeeenepol/v_3a37_3ay_3a2009_3ai_3a12_3ap_3a5075-5080.htm)

Luo, X., Wang, J., Dooner, M. and Clarke, J., 2015. Overview of current development in electrical energy storage technologies and the application potential in power system operation. Applied Energy137, pp.511-536.

[5] 82.6% in 2018 (South African Energy Sector Report 2018) http://www.energy.gov.za/files/media/explained/2018-South-African-Energy-Sector-Report.pdf

[6] Kuwano, J., Sato, N., Kato, M. and Takano, K., 1994. Ionic conductivity of LiM2 (PO4) 3 (M= Ti, Zr, Hf) and related compositions. Solid State Ionics70, pp.332-336.

Pegels, A., 2010. Renewable energy in South Africa: Potentials, barriers and options for support. Energy policy38(9), pp.4945-4954.

[7] Takada, K., 2013. Progress and prospective of solid-state lithium batteries. Acta Materialia61(3), pp.759-770.

[8] Quartarone, E. and Mustarelli, P., 2011. Electrolytes for solid-state lithium rechargeable batteries: recent advances and perspectives. Chemical Society Reviews40(5), pp.2525-2540.

[9] Kuwano, J., Sato, N., Kato, M. and Takano, K., 1994. Ionic conductivity of LiM2 (PO4) 3 (M= Ti, Zr, Hf) and related compositions. Solid State Ionics70, pp.332-336.

Computational modelling and experimental science for sustainable energy storage, mineral processing and alloy development

“We have such a lot of potential insight and capacity in Africa which can contribute towards the whole wellbeing of the world and the good of humankind.”

Prof. Phuti Ngoepe, GCRF START Co-Investigator, Director Materials Modelling Centre, University of Limpopo, South Africa

Computational modelling and experimental science have always gone hand in hand. In the past, in my research, this was with laser spectroscopy to extract optimum information from both techniques. Now we have built up the base for computer modelling here in Southern Africa, the GCRF START grant will help us take experimental science, simulations and capacity building even further, addressing global energy and climate challenges, building on more than 30 years of successful collaboration with UK scientists.

My name is Phuti Ngoepe, and I am Senior Professor and Director of the Materials Modelling Centre at the University of Limpopo (UL) in South Africa and a GCRF START Co-Investigator.  Our group uses computational modelling to study materials related to energy storage, mineral processing and alloy development themes. This research contributes to important energy and climate Sustainable Development Goals by investigating energy materials (including raw materials) for improvements in batteries central to the development of electric vehicles, solar energy storage and electricity utility backups.  Efficient mineral processing methods, which focus on water, energy and environmental conservation in the mining sector, are becoming imperative in Africa. Therefore, ‘greener’ water conserving and cost-effective approaches to mineral recovery and processing are also explored.

These themes are studied through collaborations with experimental teams using UL’s computational facilities and a petascale national computational facility at the South African national Centre for High Performance Computing (CHPC) in Cape Town, using a wide range of academic and commercial software for simulations.  Specific areas of study include computational approaches to produce nanostructures for cathodes of Li-ion batteries and emerging batteries, beneficiation of raw materials within all three themes of energy storage, and mineral processing and alloy development.

Phase stabilities of precious and light metal alloys have been examined from a combination of energetics, elastic properties and phonon dispersions, providing valuable information for aerospace applications, shape memory devices and generally powder metallurgy processing. The latter is undertaken in collaboration with South Africa’s Council for Scientific and Industrial Research (CSIR) and the University of South Africa (UNISA), the University of Cardiff (UK) and University College London (UK). Commercialisation processes are continuously pushing us out of our comfort zones, and we have even stretched ourselves to image and imitate processes that take place inside reactors in industrial pilot and production plants to help understand and solve challenging problems.

A decade ago, the mineral processing industry in South African mines approached South African universities, including UL and the Department of Science and Innovation (DSI) to employ blue sky research in modernising ways of mining and mineral extraction. In response, our group has developed stability protocols for metal sulphides hosting precious metals and proofs of concept, using computational modelling for the design of reagents that can efficiently extract metals from mineral ores, including those occurring in the Limpopo Province here in South Africa. Mineral processing is conducted with the University of Cape Town (UCT), the BGRIMM (Beijing General Research Institute of Mining and Metallurgy, China) and South Africa’s mineral mining research organisation, Mintek.

Prof. Phuti Ngoepe, Director of the Materials Modelling Centre at the University of Limpopo in South Africa and GCRF START Co-Investigator. ©Diamond Light Source

African perspectives on impact: energy storage solutions, capacity building and job creation

Ultimately, the potential impact of our collaborative research is huge.  For example, improved battery solutions for solar energy storage in Africa would mean better access to clean, affordable energy for working, cooking and learning at any time of the day or night. In addition, more efficient batteries in devices like mobile phones brings hope that one day phone batteries could be recharged just once a year!  The latter would make a huge difference to our rural people, the majority of whom rely on cell phones for communication but often struggle to access reliable energy sources to recharge.  With regards to industry and job creation, most of the materials involved in making the compounds we are investigating are mined in our region, such as manganese ores (South Africa has 80% of the world’s manganese ores), which means in terms of their beneficiation, we have possibility to harness the benefits locally by establishing industries related to energy storage.

Of course, impact is not just about scientific results; it is also about building the expertise of people. All our programmes have played and continue to play an important role in the training of postgraduate students and emerging researchers in South Africa and further afield. Much of this capacity building has benefitted from a fruitful collaboration of more than 30 years with Professor Sir Richard Catlow, Professor of Catalytic and Computational Chemistry at the University of Cardiff and Professor of Chemistry at University College London in the UK. Initially funded by The Royal Society, London (UK), and South Africa’s National Research Foundation (NRF), this partnership has afforded UK and African scientists opportunities to share skills, build capacity, and get involved in diverse and sustainable projects related to energy storage, mineral processing and alloy development. Today, our energy storage programme at the University of Limpopo is broad and involves several researchers and postgraduate students, with national and international collaborators from the South African Energy Storage Research Initiative (ESRDI), and from leading research organisations in the UK, USA and China.

We have produced highly competent systems administrators, many of whom are now based at other institutions and thus have been able to grow the capacity in computer modelling in our country. Students who qualified for PhDs in our programmes have continued and established computer modelling activities at other research institutions/universities, such as the University of South Africa (UNISA), Tshwane University of Technology, amongst others. National Laboratories such as the CSIR, Centre for High Performance Computing, Statistics South Africa, and commercial companies and SOE like Johnson and Matthey, Microsoft SA and Transnet are a few of the many high-profile labs we have been able to connect with in this way. The GCRF START grant will further assist us in our mission to develop expertise and people to take up leadership positions in South Africa and across the African continent, sharing their African perspectives on science with their counterparts in the UK.

Prof. Phuti Ngoepe, Director of the Materials Modelling Centre at the University of Limpopo in South Africa and GCRF START Co-Investigator. ©Diamond Light Source

A very promising START! Setting up of a new Li-ion battery cathode synthesis laboratory

“It is important that we invest for the long term and that the African scientific community engages with synchrotron science with the view to an African synchrotron being a reality in the not too distant future.” 

Professor Sir Richard Catlow, GCRF START Co-Investigator, The Royal Society, London; Cardiff Catalysis Institute (UK) and University College London (UK).

In terms of the science, the GCRF START grant enables us to use the latest synchrotron techniques on Diamond beamlines such as Extended X-ray Absorption Spectroscopy techniques (EXAS) and X-ray atomic pair distribution function (PDF), with our simulations complemented by experiments using samples produced from our new Li-ion Battery Cathode Synthesis Laboratory to help us understand how structural and electronic properties of the battery materials can be improved, especially in relation to the charging and discharging of batteries. 

The Li-ion Battery Cathode Synthesis Laboratory is being commissioned and co-ordinated by Dr Noko Ngoepe at the University of Limpopo. Dr Noko Ngoepe has the necessary experience through working with the cathode materials group which runs the manganese-based pilot plant in Nelspruit, and through his collaboration with the Argonne National Laboratory (USA) on the synthesis of the Nickel-Manganese-Cobalt (NMC) cathode materials. The products are lined up for further fluorination processing in South Africa, and for characterisation at Diamond together with our GCRF START Post-Doctoral researcher, Dr Cliffton Masedi.

This research also complements work carried out at the Cathode Materials Pilot Plant based in Nelspruit, South Africa, which was launched in Nelspruit in October 2017. It aims to see beneficiated manganese-based cathode materials for lithium-ion batteries developed locally at highly competitive costs, using South African raw materials. Our research is mainly intended to produce manganese rich cathode materials using the synthesis reactor. These materials will be characterised at UL and other collaborating institutions in South Africa that are participating in the Energy Storage Research Development Initiative, supported by the South African Department of Science and Innovation. It is further envisaged that some of the synthesised cathode materials will be doped in order to enhance their stability. 

Aerial view of Diamond Light Source Ltd, Harwell Campus, UK. ©Diamond Light Source

Nanostructures for cathodes of Li-ion batteries and emerging batteries

High energy density batteries are central to development of electric vehicles, solar energy storage and electricity utility backups – crucial in mitigating adverse effects of global climate change. In terms of vehicle batteries, the three major considerations are the distance vehicles such as cars can travel before recharging their batteries; how quickly the batteries can be charged; and reasonable prices of batteries. Our research is contributing to global research efforts that will ultimately produce safe, cheap, ‘green’ batteries with a longer life cycle, increased storage capacity, a wider optimal temperature operating range, and higher power output.  Many of the technologies are there, it is now a question of how to improve them: how to increase the range of travel, the length of use, how to reduce cost, and how to reduce the carbon footprint.

The enhanced performance of batteries is now achieved with nano-architecture electrodes which is at the core of what we are doing. We use world leading computational approaches to produce such nanostructures for cathodes of Li-ion batteries and emerging batteries. Valuable insights are shed on disruptive structural changes that occur during charging and discharging, and how these can be brought under control. The electrodes we study consist of nanoparticles that aggregate to form bigger/secondary particles. The nano-architecture helps to increase the capacity of the batteries, the coherence and stability of which during operation, is vital.  Currently, computational modelling studies of manganese-based cathodes such as the spinel lithium manganese oxides and manganese rich NMCs of these are explored, predicting structural stabilities, especially during charging and discharging in order to ensure long life of the batteries. These predictions guide where to put emphasis on experiments and aid in the interpretation of results. For this, access to the UK’s national synchrotron, Diamond Light Source (Diamond) with the START grant will be of enormous value.

Lithium-ion battery. Photo credit Rebekka Stredwick. ©Diamond Light Source

The impact for humanity and our planet is worth it!

“It takes more than a scientist to put things together. One must have one’s feet in different worlds: capacity building, relevance, the requirements of the science itself, and sustainable funding – it is a huge demand but worth it for humanity!”

Prof. Phuti Ngoepe, GCRF START Co-Investigator, Director Materials Modelling Centre, University of Limpopo, South Africa

With climate change and increasing socio-economic challenges facing both developing countries and the developed world, it has become more pressing than ever to invest in the next generation of scientists, and find novel, cost effective and clean energy storage solutions for the good of humanity and our planet. Most recently, during the global Covid-19 ‘lockdown’, we have watched how the world reduced its human activity (such as fossil fuel emissions) and for a short time in places nature bounced back! Yet creating sustained, lasting impact takes time and investment, as demonstrated by our research collaboration successes with the UK and others. In the space we find ourselves now (the ‘new normal’) how are we in Africa and the UK going to redefine our parameters for the benefit of future generations? What kind of world do we want to see post-Covid-19?  Collaborating well into the future with synchrotron science through the GCRF START grant is one positive answer to these difficult questions and the global challenges we all face.

It is an opportune time to strengthen this approach, as we are now in the era of Big Data, and the amount of data coming from various experimental facilities requires an integrated approach with modelling and simulation to exploit new approaches, such as Artificial Intelligence and Machine Learning. This GCRF START grant opens new avenues for exploring more hidden parameters and presents us with good opportunities.”

Dr Happy Sithole, Director of South Africa’s Centre for High Performance Computing (CHPC) and Centre Manager of the South African National Integrated Cyber infrastructure System (NICIS).

“It has been hugely rewarding working with Phuti and colleagues and with other African scientists over the last 30 years. I first visited the University of the North (now University of Limpopo) in autumn 1994. I met Phuti and a young colleague working enthusiastically in a small computer lab with one Silicon graphics machine. Over the ensuing decades we have seen develop, from this very modest beginning, a strong and successful centre that has not only produced excellent science but has populated, universities and research centres with its graduates. And I am very pleased and proud that UK scientists were able to contribute to this remarkable achievement.” – Prof. Catlow, GCRF START Co-Investigator, Foreign Secretary and Vice President at The Royal Society, London (UK), Professor of Catalytic and Computational Chemistry at Cardiff Catalysis Institute (UK), and Professor of Chemistry at University College London (UK).

Professor Sir Richard Catlow, GCRF START Co-Investigator, Professor of Catalytic and Computational Chemistry at the University of Cardiff, and Professor of Chemistry at University College London in the UK. Photo credit: The Royal Society. ©Diamond Light Source
Click here to read more about the UN’s Sustainable Development Goals.

About Prof. Phuti Ngoepe

Prof. Phuti E Ngoepe is Senior Professor, Director of the Materials Modelling Centre at the University of Limpopo and holds the South African Research Chair on Computational Modelling of Materials. Awarded South Africa’s Order of Mapungubwe Silver, Prof. Ngoepe is a Founder Member of Academy of Science South Africa. Click here for a full biography. Prof. Ngoepe is a GCRF START Co-Investigator.

Prof. Phuti Ngoepe’s Publications

About Prof. Sir Richard Catlow

Prof. Sir Richard Catlow is Foreign Secretary and Vice President at The Royal Society, London, Professor of Catalytic and Computational Chemistry at Cardiff Catalysis Institute (UK), Professor of Chemistry at University College London (UK), and a co- founder of the UK Catalysis Hub. Professor Catlow develops and applies computer models to solid state and materials chemistry — areas of chemistry that investigate the synthesis, structure and properties of materials in the solid phase. “By combining powerful computational methods with experiments, Richard has made considerable contributions to areas as diverse as catalysis and mineralogy.[1]Prof. Catlow is a GCRF START Co-Investigator.

Prof. Sir Richard Catlow’s Publications


Footnotes

[1] Source: The Royal Society: https://royalsociety.org/people/richard-catlow-11198/

Taking energy materials to the next level

Investigating lithium-ion battery cathode materials for new generation improvements in sustainable energy solutions

“Ensuring access to affordable, reliable, sustainable and modern energy for all will open a new world of opportunities for billions of people through new economic opportunities and jobs, empowered women, children and youth, better education and health, more sustainable, equitable and inclusive communities, and greater protections from, and resilience to, climate change.”

UN Sustainable Development Goal 7 – Energy[1].

Lithium-ion batteries are used around the world in everyday portable electronics, in electric vehicles as well as in small power grids.  Scientists from the Energy Materials Research Group at the University of the Witwatersrand (Wits), South Africa, study the materials needed to improve the performance, safety, affordability and environmental footprint of lithium-ion batteries in line with important sustainable development goals (SDGs). A range of different cathode materials, as well as battery chemistry is studied to increase the understanding of the materials themselves: how various synthetic routes introduce impurity phases in these materials and how this can be avoided, and what the effects are of intentional doping and co-doping of these materials[2] to explore the impact they have on the structure, performance and impurities formed.

In this work, however, laboratory-based measurements do not often reveal a clear picture of the overall structure of the material, particularly when it contains lower concentrations of impurity phases which are either below the limit at which it can be detected or cannot be resolved from the major phase. It is therefore important to firstly, employ multiple techniques to provide complementary information and secondly, to obtain high-resolution measurements from synchrotron-based techniques which expose far more in terms of other phases in the samples. This is where the GCRF START grant plays a vital part.

“A synchrotron is millions of times more capable than the equipment in our labs in terms of brightness and detail, which makes access through the GCRF START grant to the UK’s national synchrotron, Diamond Light Source (Diamond), so significant.”

GCRF START Co-I, Prof. David Billing[3], Professor in the School of Chemistry and Co-PI of the Energy Materials Research Group at Wits.

Thus far we have data from various synchrotrons for high resolution X-ray diffraction and total scattering, as well as X-ray absorption spectrometry,” says Group Co-PI, Prof. Caren Billing, lecturer and Associate Professor in the School of Chemistry. “The GCRF START grant provides us with these important experimental opportunities, alongside vital skills training and knowledge exchange for building capacity and training emerging scientists in the energy materials field.”

The ultimate aim of the Group is to address global energy, climate, and health challenges which, amongst other aims, includes enabling better “access to clean and safe cooking fuels and technologies and expanding the use of renewable energy beyond the electricity sector, as well as to increase electrification in sub-Saharan Africa[4]. To this end, improved battery storage solutions are one of a creative mix of options the Group is examining, with the help of their collaborators, including the GCRF START grant.

“GCRF START asks us to consider questions in our research around the global challenges like: am I using components that are sustainable? Are we using elements which are abundant, affordable, and environmentally compatible?”, explains Prof. Dave Billing. “In doing so, we are mindful that the economic and social situations in Europe are different to Africa: different resources, different engineers, and different environments where the solutions have to work.  Everything costs energy, fundamentally, and the whole solution has to fit the community – these are the bigger picture questions that START encourages us to ask.”

Rural village in South Africa. Photo credit: Rebekka Stredwick. ©Diamond Light Source

Some of the Group’s early career scientists focus on various lithium metal ion phosphate materials, where they are studied with the idea of using earth abundant metal ions of benefit for cost effective production and materials with a possible impact on local mining opportunities[5] to support local economies. Two of these scientists – Michelle Thiebaut from South Africa and Michelle Nyoni from Zimbabwe – are PhD research students at Wits working on lithium iron phosphate and lithium vanadium phosphate respectively, examining them as cathode materials. Both students are supervised and mentored by Prof. Dave Billing and Prof. Caren Billing, and are part of a growing number of female scientists in the Energy Materials Research Group at Wits. Michelle Thiebaut and Michelle Nyoni describe the aims, techniques and motivation for their projects in the case studies below.

Michelle Thiebaut’s research: studying Lithium iron phosphate for battery cathode materials

“When Michelle Thiebaut first started in the group, she referred to herself as “an analogue girl in a digital world”. Michelle is now the forerunner in the group in processing XAS data and has been the only chemistry student to operate the Mössbauer spectroscopy instrument in the School of Physics at Wits.” – Prof. Caren Billing, Prof. Caren Billing, University of the Witwatersrand.

Being a new researcher in a field such as energy materials is both daunting and exciting because this field is always changing and improving. One needs to change and improve one’s skill set just as quickly but the key to continue is finding one’s motivation. My main motivation is seeing how people in South Africa and in other developing countries are struggling with everyday tasks, especially people in the rural areas – tasks like coming home and doing their homework. These tasks are things many people take for granted but I think it is unacceptable that people should be struggling to get by without proper, cheap and a long-lasting access to clean energy and electricity.

My second motivation is our planet. Every person has an obligation to the planet and to live an environmentally cleaner life. By pushing science in the energy materials field means also pushing towards a greener tomorrow. Trying to break through in this field as a young female is still a bit tough with people questioning your skill set and abilities but I do think we owe former female scientists a great deal of respect for paving the way for us.

My research field is energy materials, specifically investigating the cathode material LiFePO4 found in lithium-ion batteries. My focus with this material is to find a low cost, low energy synthetic route and to possibly improve the performance. LiFePO4 is a naturally occurring mineral but can also be synthesised in a lab. This naturally occurring mineral is not phase pure[6], meaning that the iron is commonly mixed with other metals such as manganese, magnesium and calcium which lowers the electrochemical performance[7]. Cathode materials are the positive electrodes of batteries and host the mobile ions (in this case lithium). The mobile ions are the ions that are removed from the structure when the battery is being charged and when the battery discharges (depletes) the ions are inserted back into the structure[8]. Current cathode materials are not only expensive to produce but also have some safety issues like overheating and short-circuiting associated with them – challenges we want to overcome.

Compared with other cathode materials, LiFePO4 has the advantage of being environmentally friendly, meaning there are no toxic materials presents, relatively cost efficient (no expensive metals/rare earth metals needed to synthesise the material) and is structurally and thermally stable. This means that the structure does not collapse with the removal of the mobile ions and the structure prevents the battery from overcharging as well as overheating, making this material safer to use[9]. However, one of the main disadvantages of LiFePO4 is the electrochemical performance such as the ionic (movement of ions through the crystal lattice)[10] and electronic (the ability to conduct or resist electric current), which are both important properties for cathode material. The mobile ions are restricted to movement through a 1-dimensional channel. Overcoming these problems has been the main focus for most research groups[11].

In my research, the electrochemical performance can be improved by doping with a selection of different metal ions. Inserting small amounts of metal ions into the structure can improve the battery performance differently depending on the metal. For example, nickel improves the stability of the structure and enhances the movement of lithium through the structure; copper improves the conductivity and improves the reversibility of the lithium ions in the structure; and manganese improves the reversibility as well as the stability of the structure.

Exploring materials through multiple techniques and collaborative efforts

To fully understand my material, it is very important to understand how the structure changes with small changes in my synthetic method and it is the collaborative effort between the Chemistry and Physics Departments at my university – the University of the Witwatersrand – which makes this possible, and through access to world class synchrotron sources to utilise the benefits of synchrotron data to further characterise my materials.  Selected samples were sent to the Synchrotron source at Brookhaven National Laboratory (NSLS-II) in the USA and to Diamond Light Source, the UK’s national synchrotron (Diamond), with access to Diamond provided by the GCRF START grant. We have obtained data from synchrotron X-ray diffraction and total scattering, as well as X-ray absorption spectroscopy. Having remote access to state-of-the-art synchrotron equipment in this COVID-19 travel restricted world is heaven-sent as the research can continue even when no travelling is allowed.

Aerial view of the UK’s national synchrotron, Diamond Light Source, located at the Harwell Campus in Oxfordshire, UK. ©Diamond Light Source

To thoroughly characterise my synthesised materials, I have made use of our lab-based diffractometers in the Chemistry department at Wits as well as the Mössbauer spectrometer and the Raman spectrometer in the Physics department.  Mössbauer spectroscopy and Raman spectroscopy are very useful for identifying crystalline (presence of long-range order of the atoms – regular arrangement of atoms over a longer distance) as well as amorphous (only the presence of short-range order of atoms – regular arrangement of atoms but only over a short distance) species in my samples. It is important to identify all the crystalline and amorphous species in the sample as impurities can occur in both forms and could negatively affect the battery performance.

Mössbauer spectroscopy is also useful for identifying the different local iron (Fe) environments present in my sample and to determine the form of iron – (oxidation state – Fe2+ is the desired state in my samples). Raman spectroscopy aids as a structural fingerprint that can be used to determine the identity of one’s material and is also useful in identifying any impurities present that the lab diffractometers could not detect due poor detection limits or due to the phase being amorphous. Synthesised samples can have a mixture of the desired product as well as impurities. There could be multiple sources for the formation of impurities but the most common causes can be either synthesis related (impurities that are formed due to a specific synthetic route) or impurities formed due to sensitivity to air (being exposed to air could cause some small changes like a change in oxidation state of a metal). Impurities can block the channel and subsequently the movement of the mobile ion and negatively affect the performance of the material and the battery.

Michelle Thiebaut, PhD student at the University of the Witwatersrand, South Africa. ©Diamond Light Source

Michelle Nyoni’s research: investigating Lithium vanadium phosphate for improved battery cathode materials

“Michelle Nyoni is a lady who, against many odds, is striving to obtain her PhD in energy materials. Impacted currently by Covid19 travel restrictions, Michelle is normally an ‘out-of-seat’ student who works full time at Chinhoyi University of Technology (CUT) in Zimbabwe and comes to South Africa for laboratory experiments at the University of the Witwatersrand during her teaching breaks as facilities for her research topic at CUT are limited. She has worked hard during her visits here to gather sufficient data so that she can process it when she returns home and brings with her a great deal of positivity and energy on each visit.” – Prof. Caren Billing, Prof. Caren Billing, University of the Witwatersrand.

While working in the farming sector in my home country of Zimbabwe, I realised that we are blessed with abundant renewable sources of energy – wind and solar – yet hindered by the challenge of how to store this energy effectively.  This is where the subject of batteries came into my life and where my current PhD research area fits in. I am investigating lithium vanadium phosphates as cathode materials for lithium-ion batteries. I began my PhD studies part-time, in 2017, at the University of the Witwatersrand in South Africa under the supervision of Prof. Caren Billing and Prof. Dave Billing, while working as a Chemistry Lecturer at CUT in Zimbabwe.

The inspiration for my research is the fact that South Africa is one of the biggest vanadium producers in the world and Zimbabwe is one of the biggest lithium producers in the world. Therefore, if the raw materials are locally available it will hopefully mean reduced cost of battery production. My research is directly linked to Sustainable Development Goal (SDG) 7 concerning affordable and clean energy but by contributing to SDG 7, my research also contributes to achieving SDGs 1-6 and 8-9.

The aim of my research is to do much of the material characterisation by focussing on understanding what is happening at the atomic level, asking questions like: what is happening with the structure and the material? Lithium vanadium phosphate materials have been made but is this synthesis method reproducible? Does it work for upscaling to commercial levels? How do slight changes within the synthesis (preparation method) affect the material? How does adding a dopant manipulate the electrochemical properties of my material?

Lithium vanadium phosphates are potentially effective because their various properties are attractive – they have a high thermodynamic and kinetic stability, and studies have shown they possess the potential to have very good electrochemical properties, which means they will have high specific energy, high working voltage, and good cycle stability. Normally, as batteries get older, the cycling gets poorer and poorer but lithium vanadium phosphate materials have good cycle stability and a lower price tag so they are not as expensive as some of the alternative materials that can be used.   There are also other advantages. Lithium vanadium phosphate materials provide improved safety, phosphates are more environmentally friendly than some other materials[12], and the vanadium contributes to the energy density as well as the voltage of the cells – in fact, our Lithium vanadium phosphate materials can reach voltages of over 4 volts! A key application is in electric vehicles which will benefit from increased length of travel due to the cycle stability of Lithium vanadium phosphate materials and the higher specific energy density, amongst other improvements due to the advantages described above.

The cathode material determines the voltage and capacity of a battery and the cathode in a lithium-ion battery is the positive electrode, which is normally a metal oxide that is responsible for being the source of lithium ions that carry the electric current when a battery is in use (discharging)[13]. There are various components that contribute to the cost of the battery with the cathode material within the battery usually one of the biggest costs, along with the separator[14]. The lithium vanadium phosphate materials that I am working with are cathode materials, therefore if we can source these locally within the SADC region of Africa, which includes 15 member states, this would make them a lot more affordable and accessible – which is the goal I am driving at.

Cutting edge techniques to determine material characterisation and impact

The techniques I will use in my PhD studies aim to test the lithium vanadium phosphate materials in depth so that I can contribute to research that is already available to help find viable products that can be used in Africa. Techniques include powder X-ray diffraction for the phase identification and Raman spectroscopy to enable me to determine the structural finger-print to ensure I am making the same product each time so that when I do change a parameter, the resulting effect will be clear. The GCRF START grant enables us to use the Diamond synchrotron for variable temperature experiments. Therefore, I would want to look out for how the material changes when we vary the temperature. I would also use XAFS– X-ray absorption fine structure spectroscopy at the B18 beamline at Diamond to study the changes in the neighbourhoods of particular atoms.

Another technique is transition electron microscopy – the determination of particle size and the distribution of those particles as well as the general morphology of the fine particles within the material. Additionally, I want to use STA – Simultaneous Thermal Analysis – to look at the thermal stability to ask a series of questions: how stable is my material and what happens under temperature changes? Does it break down or decompose? How does this effect the overall electrochemical properties because when we use these batteries they will heat up? What is the impact, for example, if I were to leave my phone device with a battery using these materials in the sun – how would the warmth of the sun affect it? Would the structure and performance be impacted? Therefore, I would do extensive electrochemical testing which includes cyclic voltammetry and electrochemical impedance tests, amongst others, to ensure the batteries with these materials are viable in the varied environmental conditions found across Africa, including very warm environments.

Michelle Nyoni, part time PhD student at the University of the Witwatersrand, South Africa, and Chemistry lecturer at
the Chinhoyi University of Technology (CUT), Zimbabwe. ©Diamond Light Source

The GCRF START grant: a bridge to sustainable growth and life-changing possibility

“Being part of the GCRF START collaboration has certainly taken our work in energy materials in South Africa to the next level!”

Prof. Caren Billing, University of the Witwatersrand

Many of the Group’s research projects are now at the point where data has been measured and obtained and the next learning curve of how to process the data is underway. Progress has been made, Prof. Caren Billing reports, which, without funding from the GCRF START Grant, would have been an even larger hurdle to overcome.The resultis cutting-edge science and capacity building, knowledge exchange and access to the latest techniques and technology, and a new generation of gifted scientists working towards the shared vision of developing novel, green and affordable energy solutions to inspire life-changing possibility in Africa and beyond.

“This is where the GCRF START grant comes in,” says Prof. David Billing, “it provides that bridge. Yes, there’s a skills gap here in Africa but for me that gap is possibly smaller than others; as long as we are staying current on the XRD side we can transition easily and tackle the more challenging newer techniques – there’s a whole suite of them but that will grow – and START gets us there! This is also what you need to get to the higher impact journals; it also to gets us closer to current answers and future possibilities rather than just ‘the best we can do’ with 30-year-old technology.”

“In terms of energy solutions, take the scenario of load shedding (electricity cuts) which poses a huge challenge across countries in Africa. The thought of being able to go off grid is vital. If you think about a rural village which is cooking using wood or charcoal and lighting in the form of paraffin or candles – this is energy poverty. If you can find a cheap, clean, sustainable source of energy to replace these – that would be life changing!”

GCRF START Co-I, Prof. David Billing, Professor in the School of Chemistry and Co-PI of the Energy Materials Research Group at Wits.
Prof. Caren Billing, Lecturer and Associate Professor in the School of Chemistry and Co-PI in the
Energy Materials Research Group at the University of the Witwatersrand, South Africa. ©Diamond Light Source
Prof. Dave Billing, Professor in the School of Chemistry and Assistant Dean in the Faculty of Science at the University of the Witwatersrand,
South Africa; and Co-PI of the Energy Materials Research Group and GCRF START Co-I. ©Diamond Light Source

Footnotes

[1] United Nations Sustainable Development Goals: Energy for Sustainable Development, https://sdgs.un.org/topics/energy

[2] Introducing small amounts of other metal ions into the structure during synthesis without changing the structure of the material

[3] Prof. David Billing is also Assistant Dean in the Faculty of Science at the University of the Witwatersrand, South Africa.

[4] https://www.un.org/sustainabledevelopment/energy/

[5] https://www.gcis.gov.za/sites/default/files/docs/resourcecentre/yearbook/yb1919-16-Mineral-Resources.pdf

[6] An easy way to picture this is in terms of ores. Generally, an ore will contain a mixture of minerals and hence is not ‘phase pure’.

[7] Information on the natural occurring triphylite (mineral data):  https://www.mindat.org/min-4020.html as well as an electrochemical comparison: https://www.sciencedirect.com/science/article/pii/S0378775301007273?casa_token=zcBRvEsb5SMAAAAA:Lrk2oIjOY-9W73OBWasFIrxQaP7mhWNfQ4HrYjzx7Ib_r95Pq4ix8eORm0IBm29G-izoI18

[8] How Lithium batteries work in: https://www.explainthatstuff.com/how-lithium-ion-batteries-work.html

[9] Advantages and disadvantages of Lithium-iron-phosphate v lithium ion: https://blog.epectec.com/lithium-iron-phosphate-vs-lithium-ion-differences-and-advantages

[10] See Figure 1. How the lithium ions move in a battery in: https://www.spectroscopyonline.com/view/techniques-raman-analysis-lithium-ion-batteries; see also: The channels through which lithium has to move in LiFePO4  in the paper:  Yi, T., Li, X., Liu, H. et al. Recent developments in the doping and surface modification of LiFePO4 as cathode material for power lithium ion battery. Ionics 18, 529–539 (2012). https://doi.org/10.1007/s11581-012-0695-y

[11] Jingkun Li, Zi-Feng. Past and Present of LiFePO4: From Fundamental Research to Industrial Applications. Chem. Volume 5, Issue 1, 10 January 2019, Pages 3-6 (2019), Elsevier. https://doi.org/10.1016/j.chempr.2018.12.012;

V.S.L. Satyavani,A. Srinivas Kumar,P.S.V. Subba Rao.Methods of synthesis and performance improvement of lithium iron phosphate for high rate Li-ion batteries: A review. Engineering Science and Technology 19, Issue 1, March 2016, Pages 178-188. Elsevier. https://doi.org/10.1016/j.jestch.2015.06.002;

Yi, T., Li, X., Liu, H. et al. Recent developments in the doping and surface modification of LiFePO4 as cathode material for power lithium ion battery. Ionics 18, 529–539 (2012). https://doi.org/10.1007/s11581-012-0695-y

[12] Hameed, S.A., Reddy, M.V., Sakar, N., Chowdari, B.V.R. & Vittal, J.J.; Royal Society of Chemistry Advances 2015, 5, 60630-60637

[13] See: ‘The four components of a Lithium battery’: https://www.samsungsdi.com/column/technology/detail/55272.html?pageIndex=1&idx=55272&brdCode=001&listType=list&searchKeyword=

[14] See: Figure 3. ‘Total material costs of all 10 considered cell chemistries plus Panasonic NCA Use Case differentiated in combined CAM cost, anode cost, and secondary material costs’ in: Wentker, M.; Greenwood, M.; Leker, J. A Bottom-Up Approach to Lithium-Ion Battery Cost Modeling with a Focus on Cathode Active Materials. Energies 201912, 504. https://doi.org/10.3390/en12030504

GCRF START funds strategic Energy Materials Workshop

Cape Town, 16-17 December 2019

A warm South African welcome and stunning Cape Town backdrop greeted the 20 participants of the GCRF START Energy Materials Workshop, which was funded by GCRF START. The event took place from the 16-17 December 2019 and was hosted by the Catalysis Institute and c*change (DSI-NRF Centre of Excellence in Catalysis) at the University of Cape Town in South Africa.

The event kicked off with an introductory dinner at the stunning Steenberg Farm. Nationalities from Swaziland and South Africa through to the UK and Germany were represented. The Post-docs (PDRA’s), MSc. and PhD students, University lecturers, Principal Investigators (PI’s) and Co-Investigators (Co-I’s), Communications and grant staff hailed from the University of Cape Town’s Catalysis Institute (SA), University of the Witwatersrand (SA) Diamond Light Source (UK), the ISIS Neutron Source (UK), the University of Oxford (UK), Cardiff Catalysis Institute, Cardiff University (UK), the University of Southampton (UK), University of Sheffield (UK), The African Neutron and Synchrotron Data Analysis Competency (ANSDAC), and the DST-NRF Centre of Excellence in Catalysis – c*change (SA).

GCRF START December 2019 Energy Materials Workshop participants at the University of Cape Town workshop venue. Front row from left: Dr Daniel Bowron, Sikhumbuzo MasinaDr Sofia Moreno-Diaz, Dr Caren Billing, Chris Mullins, Adam Shnier; Second row from left: Mathias Kiefer, Dr Michael Higham, Dr Peter Wells, Prof. Moritz Riede, Prof. Michael Claeys; third row from left: Dr Wilson Mogodi, Dr Thomas Derrien; back row from left: Dr Mohamed Fadlalla, Dr Nico Fischer, Dr Pascal Kaienburg, Prof. Chris Nicklin, Prof. Dave Billing. Photo Credit Rebekka Stredwick, ©Diamond Light Source 

Tours of the Centre for Catalysis were given by Professor Claeys showcasing the excellent laboratory facilities and equipment available for use. GCRF START project Investigators and PDRA’s presented research covering topics including:     

  • Photo Voltaic’s – PV, batteries, fuel cells, solar cells
  • Organic solar cells and Microstructures
  • Organic semiconductors
  • Global optimisation of Cu clusters
  • Catalysis (controlling nanomaterials and structures)
  • CO2 hydrogenation
  • X-ray Spectroscopy
  • Crystallography

Presentations by Nico Fischer at ANSDAC, Michael Claeys from c*Change, and Daniel Bowron from the ISIS Neutron Source, provided insights into the collaboration opportunities through GCRF START.

Passing the mid-point of the GCRF grant is a good time to reflect on what has been achieved thus far, and is a useful time to plan ahead – both within the time of the remaining grant and how to continue the momentum into the future. With established PI’s, Co-I’s, and Post-docs attending the workshop, there was ample opportunity to share ideas for a potential GCRF START phase II, and to agree a vision and strategy for forging new ways to collaborate on the African continent in keeping with the UN Sustainable Development Goals and Pan-African 50-year mission – AGENDA 2063.

In particular, the discussion considered ways to facilitate beamtime applications within Energy Materials research. Access to Diamond can either be through an individual proposal, or through a ‘Block Allocation Group’ (BAG). GCRF START is an excellent vehicle to bring together a BAG for Energy Materials research, which also increases the networking between scientists.  Indeed, there is already a successful BAG access in Structural Biology. In addition, beamlines with robotic support allow for remote access, meaning scientists can take control of the beamline without having to travel thousands of miles to take part.

Another key point was how to increase the amount of outreach activity we do to further the impact of the grant and help foster an enthusiasm for salient science within the local population.  There are already many examples of excellent practice from individuals and institutions within the grant network such as SciArt with local crafters from the Keiskamma Art Project, as well as outreach to schools and graduates through to government ministers.

Finally, the network has grown for the grant to further increase its scope, expanding to include more researchers, institutions and organisations. There is a great opportunity to be had in teaching more about applying synchrotron science to a wider pool of researchers who may find that using the powerful X-ray beams and laboratory equipment available through GCRF START collaborators can enhance their current work and skills set.

An important aspect of all START events is networking and knowledge sharing, and participants took full advantage of the time available between presentations at coffee breaks and mealtimes to share their experiences and cement collaborations. At the end of the event, a traditional South African ‘Braai’ (Barbeque) in the grounds of the University of Cape Town aptly rounded off a thoroughly enjoyable and fruitful workshop. Interviews, photos and videos captured the buzz of the workshop to be used to share more of START’s ongoing work, achievements and impact with our current and potential stakeholders.

Photo Credit Rebekka Stredwick, ©Diamond Light Source

Across the continent, GCRF START is working with Africa to support the Pan-African 50-year mission: AGENDA 2063 .

Click here for more information about the UN’s Sustainable Development Goal for Energy.

Investigating Solar Energy – Examining the microstructure of Organic Solar Cells

“It’s been great having Mohamed as part of our team in Oxford. Such exchanges are essential if we want to solve global challenges like climate change. Among other benefits, they foster collaboration, create lasting networks and enrich the perspectives of everyone involved.”

Prof. Dr. Moritz Riede, University of Oxford, UK 
Improving Organic Solar Cell performance for energy production 

My name is Mohamed Emad Barhouma Elsayed Abdelaal and I am an Energy Materials research scientist at the Faculty of Engineering, Ain Shams University in Cairo, Egypt.  My research involves examining the micro-structure of Organic Solar Cells (OSC’s) to monitor how the performance of the cells is affected by their micro-structure under different environmental conditions. The aim is to improve the performance of Solar Cells for energy production by controlling their micro-structure and thereby to improve their benefit for alternative energy supply and pollution reduction measures.  

As the demand on the world’s classical energy resources such as petroleum products and natural gas are increasing, we must find alternative energy resources. In Egypt, for example, the government has set renewable energy targets of 20% of the electricity mix by 2022 and 42% by 20351. Egypt is therefore investing a lot of money in massive solar farms like the Benban project in Aswan and other solar energy projects. If the efficiency of OSC’s is improved through the research being conducted, then countries like Egypt might invest in more new Solar farms. In addition, since the OSC’s can be made semi-transparent and flexible, they can be installed on the glass on buildings in crowded cities like Cairo. 

Organic Solar cells are made of organic chemical materials, while traditional solar cells are made of inorganic materials, mainly silicon. OSC’s can be made semi-transparent, flexible and potentially cheaper than Inorganic Solar Cells (ISC’s), which are opaque and generally not flexible. However, ISC’s currently have a better performance and longer lifetime compared with OSC’s. Therefore, scientists are working on improving OSC’s because of their high potential to offer cheaper and more flexible energy options2.  

Building my scientific network through GCRF START  

“North-South intercultural and interdisciplinary academic exchange between the University of Oxford and Ain Shams University is of particular benefit between these two well-established universities. Mohamed, our mutual student in the GCRF START project, co-supervised by Prof. Riede and I, has benefited from the exposure to a new academic environment and the exchange of ideas and expertise.”

Prof. Dr. Ghada Bassioni, Ain Shams University, Cairo, Egypt 

This research involves international collaboration which has been encouraged and assisted by GCRF START.  One of my research supervisors, Prof. Dr Ghada Bassioni, introduced me to the opportunities offered by START as an Energy Materials researcher. I have not only been able to attend conferences and workshops to further my knowledge and skills, providing great exposure and opportunities to build our scientific network, START has given me with access to world class facilities, equipment and devices to conduct my experiments. I collaborate with Prof. Moritz Riede’s group AFMD group in the Department of Physics at the University of Oxford and some of my experiments have been undertaken there, and at the UK’s national synchrotron – Diamond Light Source.  

Mohamed Abdelaal inside the beamline I07 experimental cabin at the UK’s national Diamond Light Source synchrotron. 
Photo credit: Mohamed Abdelaal. ©Diamond Light Source 
Shining light on OSC microstructure  

I simulate the way the molecular components of Organic Solar Cell (OSC) organise themselves (the microstructure) in devices using a molecular dynamics simulations program similar to the procedure published by T. Lee et al. ACS Applied Materials & Interfaces 10, 32413 (2018). The simulations can be likened to real OSC materials ‘in situ’ and ‘ex situ’ to compare and validate the results achieved in simulation. We use a technique called X-ray diffraction which enables us to study surfaces and interfaces on an atomic scale and the micro-structure and interface evolution in real-time under vacuum conditions. 

To examine the microstructure of the OSC during evaporation, different tests are done including X-ray diffraction in the MINERVA chamber on the high resolution Beamline I07 at Diamond (Fig. 1&2) This involves evaporating the materials which make up the OSC onto a device surface (substrate) under X-ray illumination, allowing X-ray diffraction images to be collected ‘in situ’ as the materials are deposited. In this way, we can observe how the molecules change in their molecular packing (microstructure) over time as they land on the substrate microstructure. The MINERVA chamber also enables us to study how the microstructure changes in response to different environmental factors, such as temperature, humidity, and various gases. Sometimes, however, we evaporate the OSC’s at the University of Oxford using the Vacuum Evaporator (ECHO1) facility with the AFMD group, after which we examine the samples at Diamond using the X-ray diffraction process. In this case we don’t use MINERVA and the process of examination is called ‘ex situ’.  

FIG. 1. Overview of the design of the MINERVA chamber. It consists of four modules: the deposition chamber houses the low temperature evaporation (LTE) sources and quartz crystal microbalances (QCMs); the scattering chamber with beryllium windows and slits; the sample manipulator using an external hexapod to allow accurate positioning of the sample; the vacuum component chamber with all pumps, gauges, and valves. Review of Scientific Instruments88, 103901 (2017) 
DOI: 10.1063/1.4989761, Copyright © 2017 Author(s) 
FIG. 2. Cut-through of the MINERVA chamber looking from the front (access ports), showing key internal components and the path of the X-ray beam. 
Review of Scientific Instruments88, 103901 (2017) DOI: 10.1063/1.4989761, Copyright © 2017 Author(s) 
Building OSC’s and molecular dynamics simulation of OSC microstructure 

Building the OSC’s themselves is done using ‘ECHO1’, a vacuum deposition chamber at the University of Oxford. The needed materials are supplied in solid state commercially or from collaborators. The organic materials are evaporated onto a glass substrate and the layer thickness of the Solar Cell is subsequently monitored through the evaporation rate and the length of time of evaporation. Co-evaporation is also possible, which allows the evaporation of more than one organic material at the same. After achieving the required thickness, the Solar Cell is cooled down and then encapsulated inside a nitrogen filled box under inert conditions, the solar cell is ready for further examination.   

Mohamed Abdelaal using the glove box in the Vacuum Evaporator (ECHO1) at the University of Oxford  in the UK for sample handling. 
Photo credit: Mohamed Abdelaal. ©Diamond Light Source 

I started conducting my research in September 2018 and before the end of my second year, I hope to publish my first paper. During the course of my research, I personally believe that every step forward is a huge achievement, without which we would never be able to proceed further. One achievement worth mentioning is that, with Prof. Dr. Moritz Riede support, I have learned molecular dynamics simulation of the micro-structure of OSC’s. I also learned how to write scripts and although they are basic and simple, they automate the simulation which reduces the time loss between simulation steps.  Every time the simulation is completed successfully, I feel so happy and proud that I have learned something new. 

GCRF START fostering global partnerships and internationalisation  

Commenting on the importance of international partnerships such as GCRF START for students like Mohamed, Prof. Dr. Ghada Bassioni, Professor of Chemistry and Head of the Chemistry Division at the Faculty of Engineering at Ain Shams University, said, 

“Overall, the openness for African, and especially Egyptian universities to internationalisation is growing rapidly, with unhindered communication channels and inexpensive travel. Global partnerships and fostering relationships with other institutions whether on an individual or institutional basis are the main source for international students and academic exchange. International students increase social and cultural diversity, enrich the research and learning environment and help local students to develop internationally relevant skills. There are a lot of benefits for seeking an international academic environment, whether it is to develop new ideas or tap into new sources of funding or to gain access to specialised equipment. As a result of the expansion of communication methods and the ease of international travel, one in five of the world’s scientific papers are co-authored internationally.” 

Read more here about the openness for African universities to internationalisation 

Learn more about Solar energy here and the differences between Organic and Inorganic Solar Cells here  

Read more here about the UN Sustainable Development Goal 7 for Energy 

Mohamed Abdelaal profile page here

Footnotes:

1 IRENA (2018), Renewable Energy Outlook: Egypt, International Renewable Energy Agency, Abu Dhabi 

2 Organic Solar Cell Materials toward CommercializationRongming Xue, Jingwen Zhang, Yaowen Li,* and Yongfang Li  DOI: 10.1002/smll.201801793 

Investigating energy materials for efficient and cost effective conversion of sunlight into electricity

“Focusing on universal access to energy, increased energy efficiency and the increased use of renewable energy through new economic and job opportunities is crucial to creating more sustainable and inclusive communities and resilience to environmental issues like climate change”

UN Sustainable Development Goal 7: Energy

The case for localised energy generation

The rising global demand for energy and the depletion of fossil-based fuels has increased the research focus on new materials which could contribute to efficient localised energy generation, particularly in remote areas with a scarcity of electricity.

Of the nearly 1 billion people globally functioning without electricity, 50% are found in Sub-Saharan Africa alone (UN, 2019), where the focus on finding localised energy generation solutions is a welcome and timely opportunity, especially in schools and clinics located in rural areas far from the existing electricity supply or grid.

Investigating energy materials for efficient conversion of sunlight into electricity

Dr Daniel Wamwangi is a Co-Investigator within the GCRF START programme conducting fundamental research into energy materials for solutions which could one day revolutionise the energy landscape across Africa and beyond. Originally from Kenya and based as Associate Professor in the School of Physics at the University of the Witwatersrand in South Africa, Professor Wamwangi’s research on energy materials focuses on energy conversion with the aim of converting sunlight into electricity in the most efficient and cost effective way.

“The availability of alternative energy at increased efficiencies with lower costs and improved environmental footprints has domino effects on the social economic landscape,” explains Dr Wamwangi. “Benefits such as pumped water supply and purification through local solar power generators, solar based lamps and solar powered electronic devices such as cell phones could radically improve the living standards of populations in these areas.”

Dr Daniel Wamwangi performing the electronic characterisation of energy conversion materials at the University of the Witwatersrand, South Africa, using the physical property measurement system. Photo credit: Daniel Wamwangi

Finding the right energy conversion parameters

First the right parameters must be established and tested; only then can prototyping begin. There are two prongs of energy conversion that are of prime interest and focus, namely photovoltaic and thermoelectric conversion. The former involves harnessing sunlight to produce electricity, while the latter entails the conversion of heat into electricity.

The conversion of sunlight into electricity is popularly known as photovoltaics and the devices that enable the conversion are known as solar cells.

“The performance parameters that determine the commercial viability for sustainable renewable energy especially in photovoltaics include efficiency of conversion, lifetime and costs,” explains Dr Wamwangi. “In the current materials-science landscape, Silicon (Si), an element in the periodic table, has exhibited the highest efficiency of light to electricity conversion at 28%. However, the costs of processing are prohibitive and thus alternative materials and technologies are crucial to replace Si.”

This is the crux of Professor Wamwangi’s research in which cost-effective materials such as Organic materials (organic polymer based solar cell) and Inorganic materials (halide perovskites – a hybrid between inorganic and organic materials, which can be solution-based), and control of solar energy in materials (supplementary light management schemes) are investigated and developed. 1

“Hybrids are found in most cases in powder form and retain their properties even when in solution,” Professor Wamwangi explains. “They can be combined from a composite solution that is photo-responsive, which means they can take light and produce electrons and positive charges (holes) leading to voltage and electrical current.”

Supplementary light management schemes

“Supplementary light management schemes are one way to improve efficiency and this is where a lot of solar research these days is focusing. If we look at the energy budget not all the light from the sun is useful to solar devices because every material has a unique energy value,” says Dr Wamwangi. “This means that some of the light that is not used would be wasted. Therefore, we combine the energy of the light particles from the wasted light in order to increase the energy of the wasted light so it can be used by the solar cell. This increases the useful light that can be absorbed by the materials in the device.”

Light management uses nanostructures to modify the emission of light within the visible spectrum with a select number of atoms in a patterned manner to capture light (plasmonics), increasing (up conversion) and decreasing (down conversion) the energy from the sun, as Professor Wamwangi explains,

“When the energy from the sun is very large it produces hot electrons and energy is lost in the form of heat; when the temperature increases, the efficiency of the solar cell decreases, so this energy has to be decreased through the down conversion as part of a light management process.”

Organic-based solar cell devices operate on an entirely different conversion mechanism involving a combination of two interconnected materials (donor and acceptor of electrons) with entirely different electrical properties2. More recently, a hybrid of organic and inorganic materials also popularly known as Halide perovskites is intensively studied due to its associated high photo conversion efficiency.

These low-cost energy materials are predicted to replace Si-based photovoltaics through the addition of a third component to form a ternary system (three interconnected networks of materials) in consumer electronics. However, the production of current in these materials is dependent on the structure at the micro level (as previously investigated by Professor Wamwangi’s PhD student Dr. F. Otieno et al 3).

Access to state-of-the-art synchrotron techniques, collaboration and upskilling

This is where GCRF START makes a significant difference, providing researchers like Professor Wamwangi and his colleagues with access to the UK’s Diamond Light Source synchrotron and sophisticated techniques known as GIWAXS and GISAXS (Glancing incidence Wide/Small Angle X-ray Scattering). These techniques are used to study the arrangement of molecules or atoms in a solid to nanometer length scales in order to probe the type of microstructure of these materials to elucidate the electron (negative charge) and hole transport (positive) charge within the network.

© Diamond Light Source

“The factors that determine the microstructure of interconnected networks include temperature and time during processing,” says Professor Wamwangi, “Using the facilities available at Diamond through START, as well as expertise within the START family, we can correlate the microstructure with the production of current (photocurrent) and with the absorption of light on a dynamic basis.”

Besides the research fundamentals, Dr Wamwangi speaks highly of the fact that START provides a collaborative forum for scientists in Africa working in this field of Energy Materials,

“As seen in the recent publication on perovskite solar cells with START collaborators from both Africa and the UK, START increases the impact, quality and sustainability of our research publications and outputs, as well as the overall visibility and influence of African scientists and innovators globally.”

Footnote:

1) F.Otieno, B. Mutuma, M. Airo, K. Ranganathan, R. Erasmus, N. Coville D. Wamwangi 2018, https://www.sciencedirect.com/science/article/pii/S0040609017300573

2) F.Otieno, B. Mutuma, M. Airo, K. Ranganathan, R. Erasmus, N. Coville D. Wamwangi 2018

3) F.Otieno, B. Mutuma, M. Airo, K. Ranganathan, R. Erasmus, N. Coville D. Wamwangi 2018

4) Collaborators in the microstructure project of organic photovoltaics: Prof. D. Billing the principal Investigator in the START project, Wits University; Dr. Moritz Riede, Department of Physics, Oxford University, Dr. Thomas Derrien, Dr. Francis Otieno, School of Physics/Chemistry, Wits University (Professor Wamwangi’s former PhD student).