Abstract:

Beyond lithium-ion batteries, like sodium and potassium, are more abundant in the Earth’s crust and alleviate geopolitical concerns surrounding the materials inside of lithium-based batteries. However, both sodium and potassium batteries display unique interfacial chemistry that develops during electrochemical cycling in conventional electrolytes, preventing performances that are on par with current lithium systems. In the region between the electrodes and the electrolyte, a solid electrolyte interphase (SEI) is produced by the spontaneous breakdown of electrolyte compounds that dictates these inefficiencies. In my talk, I will discuss how we use nuclear magnetic resonance (NMR) spectroscopy to probe the structure and dynamics of the SEI as well as the reactions that occur at these interfaces to correlate these features with battery degradation. Insight from these methods allow us to determine the precise mechanisms of failure that arise inside of functional devices as well as develop new approaches to mitigate performance decline.