A High-Performance and Durable Poly(ethylene oxide)-Based Composite Solid Electrolyte for All Solid-State Lithium Battery

Solid electrolyte is vital for solid-state lithium batteries with higher energy and power densities. In this work, we prepared a poly(ethylene oxide) (PEO)-LiClO4–Li1.3Al0.3Ti1.7(PO4)3 (LATP) composite solid electrolyte (CSE) membrane using a simple solution-casting method. It shows high Li ion conductivity (∼1 × 10–3 S cm–1) and excellent mechanical and electrochemical performances. All solid-state lithium batteries were fabricated with the CSE membrane of PEO-50 wt % LATP, Li metal anode, and LiFePO4 cathode. By softening the CSE membrane at 80 °C, its ionic conductivity is improved, and the interfacial resistance of the prepared solid-state batteries is greatly reduced. The solid-state battery shows remarkable rate capability and excellent cycling performance. Even after 500 cycles, a capacity of 109.3 mAh g–1 is still kept at 1C. Furthermore, the CSE membrane is used to assemble a flexible pouch cell. The pouch cell can work well at different bending states, and the discharge capacity remains higher than 100 mAh g–1 at a current density of 0.2C. These results provide a promising strategy for the design of high-performance solid-state batteries.