Li2S–Li3PS4 (LPS) Composite Synthesized by Liquid-Phase Shaking for All-Solid-State Lithium–Sulfur Batteries with High Performance

Compared with traditional lithium–sulfur batteries, all-solid-state lithium–sulfur batteries assembled with inorganic solid electrolytes can not only effectively eliminate the shuttle effect but also drastically improve the safety performance. Due to the low ionic conductivity of the active materials, the construction of the interface between the active materials and the solid electrolytes in the composite cathode is crucial to the performance of the battery. Herein, Li 2 S– Li 3 PS 4 (LPS) composite materials are prepared by the in situ growth of solid electrolytes on the surface of the active material Li 2 S through the method of liquid-phase shaking. After heat treatment at 320 °C for 1 h, the 45Li 2 S–55LPS-320 exhibits a high ionic conductivity of 1.11 × 10 −4 S cm −1 , much higher than that of commercial Li 2 S. Without additional electrolytes, the Li 2 S–LPS composite mixed with a conductive agent is directly used as the cathode material. The composite cathode with high active material Li 2 S, whose content is up to 50%, delivers a discharge specific capacity of 674.3 mAh g −1 after 30 cycles at a current density of 0.2 mA cm −2 at 60 °C, with Coulombic efficiency being 100%.