Construct an Ultrathin Bismuth Buffer for Stable Solid-state Lithium Metal Batteries

LAGP (Li1.5Al0.5Ge0.5P3O12) is a promising solid-state electrolyte (SSE) for all solid-state lithium-ion batteries (ASS-LIBs) with its favorable lithium ionic conductivity and good performance on inhibiting lithium dendrite. However, the ultra-high interfacial resistance between lithium metal anode and LAGP SSEs greatly hinders its application. In this work, a thin film of metallic Bi was sputtered on LAGP to improve the chemical/physical properties of the Li/SSE interface. It is found that the Bi buffer not only inhibits the unfavorable reaction between LAGP SSEs and Li metal, but also improved their compatibility. As a result, the Li/LAGP interfacial resistance was effectively reduced from 2255.6 to 92.8 Ω cm2 at 30 ℃. Furthermore, a good performance solid state full cell with a LiFePO4 cathode had been demonstrated. This work provides an effective avenue to address the interfacial challenges between Li metal and LAGP SSE.