Electrochemomechanics of Electrodes in Li-Ion Batteries: A Review

A Li-ion battery is a system that dynamically couples electrochemistry and mechanics. The electrochemical processes of Li insertion and extraction in the electrodes lead to a wealth of phenomena of mechanics, such as large deformation, plasticity, cavitation, fracture, and fatigue. Likewise, mechanics influences the thermodynamics and kinetics of interfacial reactions, ionic transport, and phase transformation of the electrodes. The emergence of high-capacity batteries particularly enriches the field of electrochemomechanics. This paper reviews recent observations on the intimate coupling between stresses and electrochemical processes, including diffusion-induced stresses, stress-regulated surface charge transfer, interfacial reactions, inhomogeneous growth of lithiated phases, instability of solid-state reaction front (SSRF), as well as lithiation-modulated plasticity and fracture in the electrodes. Most of the coupling effects are at the early stage of study and are to be better understood. We focus on the elaboration of these phenomena using schematic illustration. A deep understanding of the interactions between mechanics and electrochemistry and bridging these interdisciplinary fields can be truly rewarding in the development of resilient high-capacity batteries.