Impact of Surface Microstructures on Diffusion-Induced Stress in Lithium-Ion Battery Electrodes: A Mechanical-Chemical Coupling Study

The Lithium-ion deintercalation induces a significant volume change in battery electrodes during charging and discharging processes, which in turn generates a large diffusion-induced stress (DIS). This stress can cause microstructural damage, consequently degrading battery performance. This work simplifies the particles making up the electrode into spheres and studies the impact of the surface microstructure on the distribution of diffusion-induced stress. A mechanical-chemical coupling model was established to study the DIS in secondary particles, which were constructed by adding convex particles to the ball-shaped particle surfaces of the electrode material. It is observed that an increase in the number of convex particles results in a higher concentration of lithium ions within the electrode material, along with the first principal stresses within the material particles. In addition, the convex particles increase the local stresses around the ball-shaped particle surface. Therefore, a round surface on the electrode material particles is beneficial for preventing potential fractures.