Lithiation‐Induced Stress in Li‐Ion Electrodes: Effects of Electrode Shapes

Under an equal‐area constraint, this study uses a two‐dimensional, bidirectionally coupled diffusion–stress model to analyze lithium diffusion and stress evolution in regular geometries (circular and polygonal) and an irregular particle reconstructed from a scanning electron microscopy (SEM) image. The results reveal that higher circularity promotes more uniform distribution of lithium, reduces von‐Mises and shear stresses, and leads to smoother, more symmetric stress fields. Electrode particles of polygonal shapes experience the largest shear stress on surface, which can cause surface damage during lithiation. For electrode particles in the shape of equilateral triangle, the largest radial stress and circumferential do not appear at the electrode center. For electrode particles of irregular shape with high boundary curvature and geometric discontinuities, there are pronounced concentration hotspots and localized stress concentrations along the periphery. The shear stress associated with local sharp corners and depressions can cause cracking and fragmentation of irregular electrode particles. These findings demonstrate that particle morphology critically influences the spatiotemporal evolution of the physicochemical fields by altering diffusion pathways and introducing boundary constraints. Enhancing circularity and optimizing boundary smoothness can mitigate stress concentration and delay mechanical degradation, offering practical guidance for the rational design of electrode architectures.