Force-chemical coupling analysis of nanocomposite anode during charging and discharging process

Anode materials are a key part of lithium-ion batteries, of which silicon-based anodes are considered the most promising electrode materials due to their high theoretical specific capacity. However, during the operation of the battery, the silicon material undergoes a huge volume change resulting in damage to the electrodes. Currently, the use of additive particles to make composite electrodes is a more reasonable approach. During the charge/discharge cycle of the battery, the electrodes may undergo cyclic expansion/contraction and may undergo elastic deformation and inelastic deformation, and lead to electrode ratchet deformation and capacity degradation. In this paper, a coupled nanoelectrode mechanics-electrochemistry model is developed to investigate the electrode stress evolution and strain accumulation of nanocomposite negative electrode during charge/discharge cycling under different influencing factors, and to analyze the change of electrochemical properties due to diffusion stress. Our work shows that the use of composite matrix materials, on the other hand, exhibits better mechanical stability, has smaller inelastic strains after a cycle, and produces less accumulation of irreversible strains. The established analytical model of nanocomposite electrode helps electrode design and is instructive for the preparation and structural design of nanocomposite negative electrodes.