Constructing dual interfacial modification by synergetic electronic and ionic conductors: Toward high-performance LAGP-Based Li-S batteries

Abstract

All-solid-state lithium sulfur (Li-S) batteries based on ceramic electrolytes provide great promise for solving “shuttle effect” and security issues. However, poor interfacial solid-solid contact and serious side reaction with lithium metal anode still hold back the development of inorganic solid electrolyte at current stage. In this work, an electronic conductive graphite layer and a composite polymer electrolyte (CPE) buffer layer have been introduced onto the cathode and anode separately and bring on an excellent electrochemical performance in Li1.5Al0.5Ge1.5(PO4)3 (LAGP)-based Li-S battery. During the electrochemical process, graphite can improve the utilization of active sulfur by serving as redox reaction sites and second current collector, and the reduction of LAGP with lithium metal is greatly alleviated by the CPE layer at the same time. Thus, interface-modified all-solid-state Li-S battery based on LAGP electrolyte exhibits outstanding cycle stability (1080 mAh g−1 after 150 cycles) and high Coulombic efficiency (almost 100%). The solid state Li-S battery with large size (4.5 cm × 4.5 cm) shows good electrochemical performance and excellent safety even under the combustion state. Consequently, constructing dual interfacial modification by synergetic electronic and ionic conductors may be an effective way to achieve high-performance all-solid-state lithium metal batteries.