Garnet ceramic fabric-reinforced flexible composite solid electrolyte derived from silk template for safe and long-term stable All-Solid-State lithium metal batteries

Abstract

All-solid-state lithium batteries (ASSLBs) using solid electrolytes are considered the most promising candidate for next-generation lithium-ion batteries owing to their high energy density and safety. However, the low ionic conductivity and limited electrochemical windows of the solid electrolytes limit the practical applications of ASSLBs. Herein, we demonstrate a simple and scalable method to prepare a solid electrolyte consisting of Li7La3Zr2O12 (LLZO) ceramic fabric by using silk as the template to form a sandwich-structured garnet LLZO ceramic fabric composite solid electrolyte (LLZO CF-CSE). The flexible LLZO CF-CSE shows remarkable thermostability and electrochemical stability (wide electrochemical window of 5.1 V vs. Li+/Li). The lithium symmetrical battery fabricated using LLZO CF-CSE can stably cycle without short circuit for 700 h at 50 °C. The ASSLB based on LiFePO4 cathode delivers high reversible capacity and excellent cycle stability at 50 °C (149.3 mAh g − 1 after 100 cycles at 0.2 C, and 107.2 mAh g − 1 after 500 cycles at 1 C). In addition, the flexible lithium metal pouch battery operates safely and stably under extreme conditions. This work provides a novel strategy for designing ceramic electrolytes with unique structures and high-energy, safe, and long-term stable ASSLBs.