Unlocking high-sulfur-content cathodes by an all-in-one high-entropy sulfide catalyst for all-solid-state Li-S batteries
Ruqin Ma, Yong Cheng, Mintao Su, Hongxin Lin, Chuanjing Xu, Wenhua Zuo, Siyuan Pan, Gongkai Wang, Yu Luo, Chenpeng Xie, Zhifeng He, Haoyue Zhong, Yuqi Wu, Weilin Huang, Huiyang Gou, Zhengliang Gong, Ming-Sheng Wang, Yong YangAbstract
Transition-metal sulfide (TMS) catalysis is a promising strategy for accelerating sulfur redox kinetics, yet its catalytic mechanisms in all-solid-state lithium-sulfur batteries (ASSLSBs) remain poorly understood. Here, two distinct catalytic failure modes are identified in conversion-type and intercalation-type TMS catalysts, namely phase-separation-driven catalyst self-poisoning and transition-metal-migration-induced electrolyte degradation, respectively. Guided by these insights, we develop an all-in-one high-entropy sulfide (HES) catalyst that undergoes a solid-solution reaction to form a stable LixHES phase. This LixHES functions as both a dual ion-electron conductor, expanding the electrochemically active reaction zone, and an interfacial redox mediator, driving spontaneous Li2S oxidation, thereby promoting extensive and rapid S↔Li2S conversion. With only 3 wt% HES, the S@HES cathode (40 wt% S) achieves 93.4% sulfur utilization and 93.0% conversion efficiency. Even at 50 wt% sulfur, the cell retains a capacity of 900 mAh g−1 at 5 mA cm−2 (2C) over 250 cycles. Furthermore, a high areal capacity of 9.68 mAh cm−2 is delivered under demanding conditions (8.5 mg cm−2, 30 °C), highlighting the great promise of the HES catalytic strategy for energy-dense ASSLSBs.