Dislocation effect on diffusion-induced stress for lithiation in hollow spherical electrode

摘要

Most lithium-ion battery electrodes undergo large volume changes caused by lithium-ion diffusion within the host particles during insertion. The electrode failure can occur as a result of diffusion-induced stress (DIS). In this work, we will develop a new model to analyze DIS with the influence of dislocation in a spherical electrode. As simple one-dimension models, solid and hollow spherical electrode particles are investigated. The results show that the effect of dislocation can relieve the DIS and even make tensile stress to become compressive stress, which differs from the classical solutions. We also compare the stress of dislocation generation in hollow sphere and solid sphere. It is shown that dislocation-induced stress in hollow spherical electrode is larger than in solid spherical electrode. In addition, based on the analytic solutions, the effect of the wall thickness of hollow sphere on DIS and dislocation-induced stress will be discussed in the hollow spherical electrode during insertion. As the wall thickness of hollow spherical electrode decreases, dislocation-induced stress increases and DIS decreases. So, dislocation-induced stress and the wall thickness will be important factors for hollow spherical electrode. These factors may help guide the development of new materials for lithium-ion battery with enhanced mechanical durability and identify battery operating conditions.