Heather Au, Imperial College London
Heather Au from Imperial College London, a Faraday Institution research fellow is designing carbon supports for sulfur electrodes as part of the LiSTAR project
Tell us about your research
I design carbon supports for the sulfur electrode in lithium-sulfur batteries as part of the Faraday Institution’s LiSTAR project. Using sulfur in batteries comes with many challenges. It’s an insulator which means that, on its own, it isn’t a good electrode material. During battery cycling, when sulfur transforms to lithium sulfide, it goes through different intermediates that can dissolve and travel around a battery in an uncontrolled way, which decreases capacity. The final conversion step to get lithium sulfide also happens very slowly.
How do you describe why your work is important to non-specialists?
Most batteries use lithium-ion technologies, which use critical materials, like cobalt, and are reaching their theoretical performance limit. To decarbonise, we need to diversify our battery chemistry to develop batteries based on cheaper, greener, abundant materials that can deliver more energy. Sulfur is an example of one of these materials. Sulfur is cheap, abundant and non-toxic. It is a by-product of the oil and gas industry but can also be acquired from other sources when we move away from oil and gas. In the future, we’d ideally have a diverse range of battery technologies to choose from to meet the performance requirements of different applications. For example, an aircraft can’t be powered using lithium-ion batteries, but we may be able to share the energy burden between a lithium-sulfur battery and a sustainable aviation fuel.
How did you get into battery research?
By accident! I didn’t have anything to do with batteries until I started my postdoctoral position with Professor Magda Titirici at Queen Mary University of London in 2018. My undergraduate degree was in natural sciences, and I specialised in chemistry. When I graduated, I didn’t want to pursue a career in science. I worked in industry for a year and a half but didn’t enjoy it, and I began to realise that I actually love science and could enjoy research. So I did a PhD investigating graphene exfoliation and functionalisation for composite applications. It was tough, and by the end I was ready to leave research again, but I thought I’d persevere and give a different environment a chance. After my PhD, I was offered a position in Magda’s group researching sodium-ion batteries. I remember she sent me a lovely email telling me not to worry about my lack of background knowledge in batteries and that electrochemistry is easy – I’ve since learned it’s actually very difficult! The opportunity to work on the Faraday Institution’s LiSTAR project came up, and Magda encouraged me to go for it, as the position gave me more independence and involves more chemistry, which I missed studying.
What is a highlight of your career to date or the aspect that gives you the greatest job satisfaction?
I love the science. Sometimes working in the lab can be a bit mundane, but I enjoy the freedom to pursue my own ideas and the scientific discussions I have with colleagues, and feel very proud when something of mine gets published. I also love mentoring students. I am an assistant supervisor for some FUSE, PhD and Imperial College undergraduate students right now, and it is great to see them become more independent and develop their own ideas.
What accomplishment are you most proud of?
I won the Sir William Wakeham award in April 2022 for my original paper ‘A revised mechanistic model for sodium insertion in hard carbons’. I am so grateful to Magda, as I would never have applied for this award without her support and encouragement. And of course the award wasn’t just a recognition of my work, but the work of a whole team of great scientists!
What opportunities has being part of the Faraday Institution opened up for you?
A lot of money is set aside for our personal development. I took a course on infographics and data visualisation, which was very useful. I can now recognise what makes a graphic effective and how best to tell a story using them, whether that’s in a presentation or a paper. The Faraday Institution also offer seminars and masterclasses, which are a great way to learn about different aspects of battery science and soft skills.
What are the biggest challenges you have overcome in your career and how have you gone about doing so?
The toughest challenge was probably my PhD. The group culture was quite demanding, and I found it hard to work without much external validation. Especially in research, there isn’t much feedback, which is hard when things often fail. I had great support from some members of my group though and that made all the difference to me continuing my studies. Having a supportive environment is so important for all researchers at every level.
I personally find it difficult to have the confidence to make myself heard in a male-dominated environment. In one early project meeting I attended, there were around 50 participants, only 5 of whom were women, and it felt very daunting walking into that room. The situation has improved a little since then, but at the time, the atmosphere made it very hard for me to engage.
Diversity in the workplace is essential for creating a welcoming environment for everyone, and it’s good to have a group leader, Magda, who understands this and has had similar experiences to me. The supportive environment I have experienced in my current group has helped foster my love of research. It’s important to not only have support from your peers, but also encouragement from the people above you. I’m at the stage now where I’m starting to apply for my own funding, and seeking out mentors with different backgrounds and experiences has certainly been helpful in motivating me to continue.
What advice would you have given your younger self starting out on your career?
Don’t take it personally! You will face a lot of rejection, especially in academia. School doesn’t prepare you for that. Sometimes I feel it would be better if people faced more rejection early on in life so they learn how to cope with it and persevere. I’m still not very thick-skinned, but I’m much more resilient than I used to be.
What are your career aspirations?
I want to continue in academia and see how far I can get. If I don’t make it, that’s okay. It’s hard! But one day, I would love to lead my own research with a small group and be a supportive group leader to other students and researchers.
If people want to find out more about your research, where would you point them to?
The Titirici group website and my paper ‘A revised mechanistic model for sodium insertion in hard carbons’.
Published August 2022.
All images from Imperial College London.
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.