A New Analytical Framework to Investigate the Precipitation Kinetics of Discharge Products in Li-S Batteries

Polysulfides are central to the inner workings of lithium-sulfur (Li-S) batteries. They are responsible for the inertia and snowballing effects at play on the dynamics of the battery, among those, the infamous shuttle effect. For this reason, it is very challenging to establish analytical tools for quantitative investigations of Li-S batteries. The need for such analytical tools is particularly crucial when applied to precipitation dynamics, which is a key limiting step to the sulfur utilization and rate performance of the Li-S battery. Here, controlled experimentation is conducted to record the precipitation signatures for micro-electrodes and conventional porous electrodes for Li-S chemistry. It is unraveled how the polysulfide species, involved in the disproportionation reactions, control the peak shape and trends in the chronoamperometric profile of a sulfur electrode. This enables the foundation to be set for a new analytical framework for quantitative characterization of the precipitation mechanism in Li-S batteries.