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Designing solid-state electrolytes for high-energy lithium-metal batteries

August 20, 2019
Amir Kader
Mechanical Engineering, Class of 2021

Being able to be a part of the Bao Group so far has been an illuminating experience for me both academically and personally. I am fortunate enough to learn from some of the most accomplished professionals in their respective fields and am grateful to SUPER for this opportunity.

The project that my mentor Snehashis Choudhury (Sneh) and I have been working on attempts to design a solid-state electrolyte for lithium-metal batteries. Batteries that use lithium metal as their anodes have the potential to operate at specific capacities more than 10 times those of the popular lithium-ion batteries used today. Multiple challenges exist with these lithium-metal batteries though — namely the formation of dendrites — and designing a solid-state electrolyte that has both high ionic conductivity and considerable mechanical strength is a sound strategy for hindering dendrite formation.

Before joining the Bao Group, I had imagined lab work to be more of a repetitive task with less room for creativity. I now know that this assumption is entirely false. Being in the lab is a rich thought experiment which demands a deep devotion towards better understanding and simultaneously improving the project at hand. The aim of scientific research is to uncover and share fundamental concepts that are not yet well understood — with the hope that doing so will advance the field as a whole. Although we can have expectations about our experiments, there is never a sure path to our work, which helps to keep the research exciting and educational. Sneh has been a constant source of learning and inspiration to me.

My typical day in the lab begins with reading any scientific literature that may provide insight into our own project. Sneh and I then proceed by designing and executing experiments that are elegant enough to expose new knowledge. We then make sense of our results, tweak things that we are not happy with, and sometimes completely change the experiment’s path. Right now, we are testing the material strength and ionic conductivity of our electrolyte with varying salt concentrations. If things don’t work out, Sneh and I may decide to start from the beginning by tweaking the electrolyte itself. That can be the nature of research — hoping for one result but finding an entirely different one. And that can be a good thing. Sneh told me during our first week that he likes to be “positive but not over-optimistic.” Expect little. But stay hopeful and work hard. 

Other projects exist that work on solid-state electrolytes. The key in our work, however, is that we are designing an electrolyte that functions by simple chemistry that can advance the current knowledge both from applied and fundamental aspects. Most projects in the literature today utilize poly(ethylene oxide) and some cross-linking mechanisms with other polymers or nanoparticles to obtain some solid electrolyte. The chemistry we use is different though. We don’t use poly(ethylene oxide), which has a low electrochemical stability window, and in turn limits its usage in high energy batteries.

The battery sub-group has a clear goal: to develop a high-performance battery that can address today’s energy and environmental needs. Before starting SUPER, I knew that I wanted to try and accomplish big things in the energy sector generally. I am glad that I have now refined my goal to something more specific: batteries. There is a diversity of solutions towards developing better batteries. As is required with the nature of research though, I will continue to be open-minded about all projects that are working to help accelerate the transition to clean energy.

Sneh has been a huge force in helping me to be open-minded and driven. I often like to manufacture new ideas to improve batteries that are unrelated to our project. Sneh is always supportive with feedback and even offers to take some of the ideas up as new projects in the coming years. Next summer, I may aim for a more industry-oriented project  — which I think will suit the more entrepreneurial and tangible side of the work — to compare my feelings about research and industry.

If there is one thing to take away from my experience so far: be positive but not over-optimistic.