Effect of current density on the Li – Li6PS5Cl solid electrolyte interphase

Understanding the nature and evolution of interphasial products at the Li metal – solid electrolyte interface is crucial in solid-state lithium batteries (SSBs). Using operando X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy, we highlight the role of lithium plating current density on the evolution of the Li6PS5Cl–Li solid electrolyte interphase (SEI) composition in a “lithium-free” anode configuration. We conclude that higher current densities facilitate the formation of a more uniform, Li3P-rich SEI thereby decreasing the electrode-electrolyte interfacial impedance. This study improves understanding of the role of plating kinetics in lithium-free SSBs and suggests a new strategy to modulate electrode-electrolyte interphases to achieve more efficient lithium plating.