Mechanical Stress-Tolerant Diffusion-Dependent Electrode With Well-Dispersed Silicon Particles for High-Performance All-Solid-State Batteries

Abstract

All-solid-state batteries (ASSBs) are a promising next-generation energy storage solution due to their high energy density and enhanced safety. To achieve this, specialized electrode designs are required to efficiently enhance interparticle lithium-ion transport between solid components. In particular, for active materials with high specific capacity, such as silicon, their volume expansion and shrinkage must be carefully controlled to maintain mechanical interface stability, which is crucial for effective lithium-ion transport in ASSBs. Herein, we propose a mechanical stress-tolerant all-solid-state graphite/silicon electrode design to ensure stable lithium-ion diffusion at the interface through morphology control of active material particles. Plate-type graphite with a high surface-area-to-volume ratio is used to maximize the dispersion of silicon within the electrode. The carefully designed electrode can accommodate the volume changes of silicon, ensuring stable capacity retention over cycles. Additionally, spherical graphite is shown to contribute to improved rate performance by providing an efficient lithium-ion diffusion pathway within the electrode. Therefore, the synergistic effect of our electrode structure offers balanced electrochemical performance, providing practical insights into the mechano–electrochemical interactions essential for designing high-performance all-solid-state electrodes.