An In Situ Solidifying Strategy Enabling High-Voltage All-Solid-State Li-Metal Batteries Operating At Room Temperature

At present most reported all-solid-state Li-metal batteries (ASSLBs) have to operate at elevated temperature due to the huge resistances at solid-solid interfaces. Also, the poor stability of solid-state electrolytes (SSEs) against both Li metal and high-voltage cathodes largely restricts the development of high-voltage ASSLBs featuring high energy density. Herein, a succinonitrile-based solid polymer interlayer (SPI) is in situ introduced at the Li1.5Al0.5Ge1.5(PO4)(3) (LAGP)-Li and LAGP-cathode interfaces. The SPI perfectly fills all cracks and voids at solid-solid interfaces, and exhibits high ionic conductivity and a wide electrochemical window up to 4.8 V, which not only provides fast interfacial lithium-ion transport, but also significantly improves the interfacial stability of the SSEs against both Li metal and high-voltage layered oxide cathodes. Therefore, the SPI-based symmetric cell shows stable cycling at 0.1 mA cm(-2) for 600 h and a high critical current density of 7 mA cm(-2). The LiNi0.8Co0.15Al0.05O2-SPI-LAGP-SPI-Li cell shows a high capacity of 200 mA h g(-1) at 0.1C and stable cycling after 100 cycles at 0.5C with a capacity retention of 80% at room temperature. This work presents an effective and practical strategy to achieve outstanding performance of room-temperature ASSLBs with high output voltage.