"Underpotential lithium plating on graphite anodes caused by temperature heterogeneity"

Hansen Wang: Yangying Zhu, Sang Cheol Kim, Allen Pei, Yanbin Li, David T. Boyle, Hongxia Wang, Zewen Zhang, Yusheng Ye, William Huang, Yayuan Liu, Jinwei Xu, Jun Li, Fang Liu, and Yi Cui; Proceedings of the National Academy of Sciences, 11/09/20.

Additional Authors: Yangying Zhu, Sang Cheol Kim, Allen Pei, Yanbin Li, David T. Boyle, Hongxia Wang, Zewen Zhang, Yusheng Ye, William Huang, Yayuan Liu, Jinwei Xu, Jun Li, Fang Liu, and Yi Cui

Abstract:

Rechargeability and operational safety of commercial lithium (Li)-ion batteries demand further improvement. Plating of metallic Li on graphite anodes is a critical reason for Li-ion battery capacity decay and short circuit. It is generally believed that Li plating is caused by the slow kinetics of graphite intercalation, but in this paper, we demonstrate that thermodynamics also serves a crucial role. We show that a nonuniform temperature distribution within the battery can make local plating of Li above 0 V vs. Li0/Li+ (room temperature) thermodynamically favorable. This phenomenon is caused by temperature-dependent shifts of the equilibrium potential of Li0/Li+. Supported by simulation results, we confirm the likelihood of this failure mechanism during commercial Li-ion battery operation, including both slow and fast charging conditions. This work furthers the understanding of nonuniform Li plating and will inspire future studies to prolong the cycling lifetime of Li-ion batteries.