I was fascinated by the idea of using super-concentrated electrolyte to broaden the operational potential window. Driven by my curiosity, I scheduled a meet-up with Dr. Xu to know more about his research.
 
What is your research about and what is your motivation in doing his research?
Dr. Xu: My research focuses primarily on the interface between electrodes and electrolytes of lithium-ion batteries. I chose this topic because the interface is a crucial and challenging part that dictates the overall performance of batteries.
 
How did the idea of using super-concentrated salt aqueous solutions to widen the voltage windows of lithium-ion batteries originate?
Dr. Xu: I transplanted the knowledge from non-aqueous electrolytes. For most organic electrolytes, they are able to form solid-state interfaces on electrode surface and to stabilize large voltage windows. In my past research experience I have learned that solvation sheath structure of cation often determines SEI on the anode side. Inspired by the concept, I needed to drastically change the solvation sheath structure of Li-ion in aqueous solution, and the only effective way of doing so is to increase the salt concentration to “insane” level, so that anions are forced into the solvation sheath. It eventually leads to an SEI mainly contributed by anion decomposition.
 
What pieces of advice he would give to those graduate students who just start?
Dr. Xu: Think outside of the box, and always take what the authorities tell you with a grain of salt.

I later found that Dr. Xu and I are both born in Chengdu, China.