Decoupling pressure effects in plating and stripping of lithium metal anodes

Abstract

Lithium metal anodes hold great promise in realizing high-energy-density secondary batteries. However, improper plating and stripping are susceptible to forming lithium dendrites and dead lithium, causing battery capacity degradation. During the full cycle of plating and stripping, mechanical stress intertwines with electrochemical transfer and reactions. The mechanism of pressure effects in plating and stripping behavior remains ambiguous. Therefore, we develop an electro-chemo-mechanical phase-field model to describe the plating/stripping behavior, with key parameters quantifying dendrite and dead lithium formation, revealing that pressure can optimize electroplating morphology and converse stripping pattern. We successfully decouple the pressure effects from plating and stripping, elaborate the impact of plating and stripping pressure on battery capacity decay, and construct a phase diagram of irreversible capacity loss rate for plating and stripping pressure, clarifying the relevance of pressure and capacity loss. Moreover, we summarize and illustrate the dependent relationship between pressure-induced electroplated morphology and stripping patterns. This work demonstrates and decouples a critical pressure mechanism on lithium plating and stripping, providing new insights into the optimization and modulation of pressure management strategies for lithium metal batteries.