Kinetic analysis of cathode-solid electrolyte interface in all-solid-state batteries

High interfacial impedance hinders the development of all-solid-state batteries. While thermodynamic analyses offer stability insights, they overlook the kinetic effects that dominate during operation. Here, we use a machine learning interatomic potential to perform long-timescale molecular dynamics simulations of various cathode/solid electrolyte (SE) interfaces, including sulfide, chloride, and oxide SEs with layered LiCoO₂. Our simulations reveal three primary kinetic mechanisms driving impedance: (1) interfacial reactions, especially with sulfide SEs, forming poorly conducting interphases; (2) the formation of lithium-depleted regions that reduce available Li⁺ pathways; and (3) cation inter-diffusion, which obstructs lithium transport channels and degrades the cathode. These findings underscore the critical role of kinetics in interfacial stability and establish machine learning-driven atomistic modeling as a powerful tool for designing next-generation solid-state batteries.

© The Royal Society of Chemistry 2025