Dynamics of Lithium Stripping on Graphite Electrodes

Abstract

As fast charging of lithium-ion batteries becomes a critical barrier to the widespread adoption of electric vehicles, development of facile methods of detection and quantification of lithium plating is a top priority. The voltage plateau observed during the rest or discharge phase ensuing a charge in which plating has occurred is a popular in-operando signature of lithium plating. Recent works have shown that the length of the stripping plateau is not a reliable metric for plating quantification, as was previously thought. An improved analytical method for relative quantification of lithium plating is presented herein. Furthermore, an in-situ method is developed for direct visualization of lithium stripping and graphite phase redistribution during the open circuit rest phase after charge. The dependence of lithium stripping dynamics on temperature and charge rate are comprehensively investigated. These techniques help in understanding the mechanistic underpinnings of the stripping processes occurring in the graphite electrode during relaxation after fast charging and enhance the capability to study lithium plating in a non-destructive manner.