Stabilizing Li Metal/Argyrodite Interface for Sulfide-Based All-Solid-State Lithium Batteries

The achievement of carbon neutrality is the first step in addressing the issue of global climate change. Rechargeable batteries with high energy density are one of the promising techniques to reduce carbon emission. After the commercialization of lithium-ion batteries (LIBs) in 1991, rechargeable LIBs have been universally applied in portable electronic to electric vehicles. However, the conventional LIBs using liquid electrolytes have serious safety problems such as flammability, solvent leakage, and explosion under unusual conditions. In addition, the use of Li metal anode (3860 mAh g^-1) with high specific capacity tends to exacerbate risks due to the interfacial side reactions and dendrite growth of lithium. In this respect, all-solid-state lithium metal batteries (ASSLMBs) have attracted attention as the most promising high energy density storage system. Among various solid electrolyte systems, sulfide electrolytes are being widely studied due to their high ion conductivity and ductile property. However, the lithium dendrite growth can be also occurred in sulfide based-ASSLMBs because of voids, cracks, grain boundaries in solid electrolyte, and side reactions between Li and solid electrolyte.<br/>In this work, the surface modification of Li was performed using LiNO₃ with nitrogen-based solvent. The protective layer formed on Li metal was composite of organic and inorganic materials based on Li₃N. The symmetric Li/solid electrolyte/Li cell with protective layer exhibited good cycling stability without short circuit, indicating the uniform plating/stripping of lithium and good interfacial properties. Consequently, an all-solid-state lithium battery assembled with LiNi_xCo_yMn_1-x-yO₂cathode delivered a high initial discharge capacity and exhibited good cycling stability.