Li–Sb Alloy Formation Strategy to Improve Interfacial Stability of All‐Solid‐State Lithium Batteries

The solid electrolyte is anticipated to prevent lithium dendrite formation. However, preventing interface reactions and the development of undesirable lithium metal deposition during cycling are difficult and remain unresolved. Here, to comprehend these occurrences better, this study reports an alloy formation strategy for enhanced interface stability by incorporating antimony (Sb) in the lithium argyrodite solid electrolyte Li₆PS₅Cl (LPSC-P) to form Li-Sb alloy. The Li-Sb alloy emergence at the anodic interface is crucial in facilitating uniform lithium deposition, resulting in excellent long-term stability, and achieving the highest critical current density of 14.5 mA cm^-2 (among the reported sulfide solid electrolytes) without lithium dendrite penetration. Furthermore, Li-Sb alloy formation maintain interfacial contact, even, after several plating and stripping. The Li-Sb alloy formation is confirmed by XRD, Raman, and XPS. The work demonstrates the prospect of utilizing alloy-forming electrolytes for advanced solid-state batteries.