Phase-Field Modeling of Solid Electrolyte Interphase (SEI) Cracking in Lithium Batteries

Abstract

The formation of solid electrolyte interphase (SEI) can cause battery capacity fade and increase cell internal resistance, while inhibiting further electrolyte decomposition. Lithium-ion diffusion during lithiation and de-lithiation can lead to the stress evolution as well as crack propagation of the SEI. This is one of the major factors that shorten the lifespan of lithium-ion batteries. Therefore, coupling the stress evolution and crack propagation in SEI layer during the lithium ion diffusion is of an important significance to improve the understanding of lithium-ion battery. In this paper, a phase field model is developed to simulate the stress evolution and crack propagation during the lithium ion diffusion. Then the model is applied to study the SEI layer formed on the LiMn2O4 electrode. The simulation results indicate the crack propagation patterns in the SEI layer during lithium ion diffusion.