Morphology-Dependent Stress Evolution and Capacity in Lithium-Ion Battery Anodes: A Chemo-Mechanical Study

Silicon (Si) is a high-capacity anode for lithium-ion batteries, but significant volume variations during cycling cause mechanical failure and capacity fade. Porous composite anodes with Si coated on a metallic scaffold can be designed to mitigate expansion-induced degradation. In this work, we use multiphysics finite element simulations to study the effects of curvature, morphology, Si layer thickness, and charge rate (C-rate) on the evolution of stress and capacity during lithiation of a shell-based architected anode. We find that the uniform domains and negative Gaussian curvature of gyroid and spinodal morphologies promote homogeneous lithiation, improved active material utilization, and reduced expansion-induced stress. Additionally, the chemo-mechanical performance of minimal surface (negative Gaussian zero-mean curvature) morphologies is less sensitive to changes in domain size, Si layer thickness, and C-rate compared to equivalent inverse opal structures, making them well suited for high-capacity and fast-charging applications. Collectively, these findings underscore the critical role of morphology in architected electrodes and provide a framework for designing robust, high-capacity anodes for next-generation lithium-ion batteries.