Issue of Lithium-indium Anode in High Energy and Power All-Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) using sulfide solid electrolytes (SSEs) offer an attractive option for energy storage applications. Lithium anode is the ultimate goal for ASSLBs, but lithium-indium (Li-In) alloy anode is more widely utilized in lab testing owing to the quite stable interface and elimination for the risk of short circuit. However, vigorous growth of Li-In dendrites in SSE is discovered in the present work when a full cell (LiNbO3 coated LiNi0.6Co0.2Mn0.2O2//Li6PS5Cl//Li-In) is cycled in high loading and high rate. Our study demonstrates that Li-In anode is unstable towards SSEs at high current, which induces Li-In dendrite growth enclosing electrolyte particles and eventually results in cell death after a long cycling. The morphology and growth mechanism of Li-In dendrites are revealed by scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) analysis and density function theory (DFT) calculations. Moreover, the differences between Li and Li-In dendrites are systematically compared.