Unlocking high-energy solid-state lithium-sulfur batteries with an innovative double-layer hybrid solid electrolyte

Abstract

This study developed a novel double-layer hybrid solid electrolyte (DLHSE) to address the limitations of solid-state lithium–sulfur (Li–S) batteries, which include poor electronic/ionic conductivity, interfacial chemical/electrochemical instability, and substantial interfacial resistance between the solid electrolyte and electrodes. The DLHSE comprises an ion-conducting ceramic, electrochemically stable polymer, and ether-based liquid electrolyte. Specifically, the dual-layer ceramic skeleton comprises an inorganic NASICON-type Li1+xAlxTi2-x(PO4)3 (LATP) layer facing the cathode to facilitate Li+ migration at the interface and a garnet-type Li7La3Zr2O12 (LLZO) layer facing the anode to suppress Li dendrite formation and mitigate the “shuttle effect”. The polymer binder (PVDF–TrFE) can create a three-dimensional network to enhance structural compactness and stability. The penetrating ether-based electrolyte can facilitate Li+ transfer and reinforce the interfacial contact. Furthermore, a well-designed porous carbon rod/sulfur (PCR/S) composite with an ultrahigh sulfur content of 80 wt% was prepared as the cathode. Consequently, the novel structural configuration with PCR/S cathode and DLHSE, not only demonstrated excellent coin-cell performance with a capacity retention of 802 mAh g−1 after 500 cycles at 0.2C, but also an outstanding A-h-level pouch cell with an impressive discharge capacity of 7 Ah at 0.1C.