Analysis on diffusion-induced stress for multi-layer spherical core-shell electrodes in Li-ion batteries*

Abstract

Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes. Herein, a multilayer spherical core–shell (M-SCS) electrode with a graphite framework prepared with Si@O-MCMB/C nanoparticles is developed, which aims to realize chemically/mechanically stability during the lithiation/delithiation process with high specific capacity. An electrochemical-/mechanical-coupling model for the M-SCS structure is established with various chemical/mechanical boundary conditions. The simulation of finite difference method (FDM) has been conducted based on the proposed coupling model, by which the diffusion-induced stress along both the radial and the circumferential directions is determined. Moreover, factors that influence the diffusion-induced stress of the M-SCS structure have been discussed and analyzed in detail.