Atomic-scale Al2O3 modified PEO-based composite polymer electrolyte for durable solid-state Li − S batteries

Abstract

Abstract The dissolution of lithium polysulfides in the polymer-based electrolyte and the electrolyte/lithium interface instability lead to the poor cycling stability and low Coulombic efficiency of solid-state Li S batteries. Herein, an ultrathin Al2O3 layer is deposited on the polyethylene oxide (PEO) based composite polymer electrolyte (CPE) by atomic layer deposition (ALD) to build a stable electrolyte/lithium interface, which could inhibit the shuttle effect of lithium polysulfides and restrain the growth of Li dendrite. An ultralong life in Li Li symmetric cell with CPE/Al2O3 can be achieved over 1200 h. The solid-state Li S batteries with the flexible CPE/Al2O3 membrane also deliver the electrochemical performance with high initial capacity of 1415 mAh g−1 and a reversible capacity of 640 mAh g−1 after 120 cycles at 0.1C. In addition, the fabricated punch cell with CPE/Al2O3 can endure the harsh treatment and operate at least 50 cycles, showing great potential in practical application.