Qiong Cai, reader in chemical and process engineering at the University of Surrey is using multiscale modelling to develop new battery materials as part of the LiSTAR project
Tell us about your research
My research is centred around designing materials for batteries using a combination of computational modelling and experiments. I use multiscale materials modelling, which involves rendering from atomic scale to micrometre scale using different modelling tools such as density functional theory, molecular dynamics, and mesoscale methods. We have used atomistic modelling to design various anode materials and electrolyte for various batteries, and to reveal fundamental mechanisms. Some examples can be found in our papers published in Nanoscale, Advanced Functional Materials, Journal of Materials Chemistry A, Small, and Chemical Engineering Journal. We have also developed a 3D pore-scale lattice Boltzmann model to rapidly simulate large electrode microstructures with multiphase flow, such as 3D porous shapes, as explained in our paper published in Journal of Power Resources. We collaborate widely with experimentalists, to validate our models, and to provide explanations to experimental observations.
We hope to use these modelling tools to review how the chemistry and physics of a material affects the battery’s performance. A lot goes on inside a battery, such as electrochemical reactions, molecular interactions, ion adsorption and intercalation, and diffusion. We try to capture all these phenomena in our modelling. Once we build up a good understanding of how processes affect battery performance we can develop novel materials with potentially high performance that guide experimental work.
Why is your work important?
To use a cooking analogy, when I cook, sometimes I like to try out different things. I will try using various ingredients, cooking materials, and cooking methods like steaming, frying, and baking. When you experiment with your cooking, you don’t always know what you’re going to get, so if things don’t work out, you can waste a lot of materials. To improve batteries, we need to experiment with different materials and methods, but if we build new batteries each time we want to experiment, we could waste lots of expensive materials. Modelling allows us to experiment without wasting materials. It also tells us about the fundamental processes, whereas most lab techniques can only tell us about general performance without the underlying causes and contributions.
How did you get into battery research?
I started working on fuel cells and electrolysis hydrogen production as a postdoc at Imperial College London. When I became an academic, it was around the time people realised the importance of batteries for energy storage, and I wanted to contribute to this field. So, I applied for my first grant to use atomic scale modelling to review the structural effects of hard carbon as anodes for sodium-ion batteries. Since then, I’ve worked on many different battery technologies because the skills are transferable. I have worked on sodium batteries, lithium-ion, and now aluminium-ion and zinc-ion batteries, each with their own advantages and limitations.
What accomplishments are you most proud of?
Probably how I’ve established myself in the field of multiscale material modelling. Some people work on an atomic scale, and some on a mesoscale, and I’m proud that I’ve been able to work on multiple scales. It helps that I have done both in the past – during my PhD at the University of Edinburgh, I worked on molecular modelling and moved on to mesoscale modelling during my postdoc at Imperial College London, and now I combine them. It was a challenging learning process at the start!
I am also proud of our work applying a material used in lithium-ion batteries to aluminium-ion batteries that enhanced their performance. Our paper was published in Advanced Energy Materials.
What is a highlight of your career to date or the aspect that gives you the greatest job satisfaction?
I love seeing young researchers in my group develop their research skills and go on to thrive in academia and industry, and I do my best to provide a supportive environment that allows them to do so. For example, one of my recent postdocs Dr Emilia Olsson joined my group in December 2017 for an EPSRC project on sodium ion batteries, in collaboration with Professor Magda Titirici at Imperial College London, and Professor Alan Drew and Professor Martin Dove at Queen Mary University of London. I have seen how she has grown in the 3 to 4 years working in my group. Towards the end of the project, we helped her by doing mock interviews and looking over her job applications. She is now an assistant professor at the University of Amsterdam leading her own group. It makes me so happy to see people develop their passion for research and grow into independent researchers!
What are the biggest challenges you have faced during your career, and how have you gone about overcoming them?
When I started my independent academic career at the University of Surrey I was the only female academic in my department, and had my second child in my first year of probation. After my maternity leave, the number of students had doubled, and a few academic staff left the department, so everyone, including me, had to take on a much greater teaching load, whilst I was looking after two young children. I didn’t know many female academics and felt very lonely and isolated. Networking and meeting people is really important for academics to establish their research and open connections for collaboration, and I didn’t have the mobility and capacity to do that at the time. By the end of my second year, I was ready to give up on an academic career. Then I went to a conference on materials at the University of Bath, where I met Professor Judith Driscoll from the University of Cambridge, who talked about having two children and working as a female academic. She showed such kindness and willingness to help, and kept in touch with me. She made me believe that it could be possible to have children as well as a thriving academic career. Later in a chat with Dr Alex Roberts (then postdoc at Surrey, now Professor at Coventry University), he told me about Magda Titirici who had moved from Germany to Queen Mary University of London. I went to see Magda, and she kindly supported two grant applications I put in that year. We have been in collaboration since then.
I have seen positive changes in the last few years. Now we have 7 female academics in the department! There are now good support mechanisms for young academics, and schemes available for those needing to take a career break, such as the Vice Chancellor Academic Returner Award at the University of Surrey that helped me after my third child.
What do you think of senior researchers helping to establish the next generation in academia?
It’s so important for established people to be willing to help younger academics. I have received support from a number of senior researchers (e.g., Professors Nigel Brandon, Claire Adjiman, Nigel Seaton, Bob Slade, John Varcoe, Charley Wu, Guoping Lian, Mark Biggs) who provided advice, shared tips on applying academic positions, helped with interview preparation, shared lab space and industry contacts, shared successful proposals, and involved me in PhD supervision when I did not have any PhD students. Their kindness has made my academic journey less bumpy. When someone you look up to shows kindness and is willing to help, it can make a big difference.
I recently met with Professor Zi-Kui Liu from Pennsylvania State University who is a world-renowned expert in developing materials simulation methods. I was interested in applying a new method Prof Liu developed to my research. When I wrote to him, he immediately invited me to visit him at Cambridge where he is a visiting Fellow, and spent an hour and a half answering my questions. I enjoyed discussing science with him, and was very touched that such a highly recognised expert was kind enough to spend so much time helping me.
What are your career aspirations?
I’d love to develop some amazing technology that changes the world! But, I know that research is about the little steps we take along the way to that goal.
What opportunities has being part of the Faraday Institution opened up for you?
The LiSTAR project is a big consortium of universities, which allows me the opportunity to collaborate with people I usually wouldn’t have the chance to connect with.
What advice would you have liked to have given your younger self starting out on your career?
I would tell myself not to be afraid of reaching out to people because there is always someone kind and willing to help, and collaborating with experts is a wonderful opportunity for learning.
What is your favourite battery-related fact?
I often tell my undergraduates about John B Goodenough, who invented lithium cobalt oxide as a cathode material for lithium-ion batteries in 1980, which doubled battery capacity. He is the oldest to have been awarded a Nobel prize at 97. He is now 100 years old and still working on battery research!
If someone wants to find out more about your research, where would you point them to?
There is a lot of information on my webpage. This paper published in Advanced Energy Materials sums up our atomic-scale materials modelling, and this paper published in Advanced Energy Materials explains our work improving aluminium-ion batteries with a material used in lithium-ion batteries.
Published September 2022.
About the author: Cara Burke is the Faraday Institution’s Science Communications Intern in the summer of 2022. She has just completed her BSc Biological Sciences degree at Imperial College London and is pursuing a career in science communications.