"Understanding the Interplay between Li Intercalation and Li Plating Using Single Graphite Particle Electrochemistry"

Tao Gao: William C. Chueh, Ju Li and Martin Z. Bazant; ECS Meeting Abstracts, 05/01/20.

Additional Authors: William C. Chueh, Ju Li and Martin Z. Bazant

Abstract:

Potential safety hazard of lithium ion batteries, their long recharging time and performance degradation during usage are the major obstacles that prevent the wide adoption of electric vehicles in our society. Lithium plating on graphite anode is considered the leading cause of thermal runaway, degradation and the barrier for fast charging. However, the onset of lithium plating on graphite anodes is not well understood. For the first time, we resolved the spatial dynamics of lithiation of a single graphite particle using in-situ optical microscopy, and shed light on the interplay between lithium intercalation and plating. Enabled by simultaneously monitoring of the voltage, phase transformation and lithium plating, we are able to elucidate the energetics and kinetics of the two competing reactions, and establish a comprehensive mechanistic picture of Li plating mechanism on graphite anode. The proposed mechanism was further validated by simulation using a 1-D phase field model. This work is therefore providing insights on guidelines of designing graphite anode and operating LiB for reducing the risk of lithium plating.