Synergism of Covalent Linkage and Bimetallic Atom Catalysis Enables High‐Performance Cathodes for Li–S Batteries Under High Sulfur Loading and Low‐Temperature Conditions

Abstract

Abstract Lithium sulfur batteries (Li–S) with high theoretical specific capacity have aroused great interests in the field of energy storage. However, shuttle effect and slow conversion kinetics of lithium polysulfides seriously affect its practical application. Particularly, Li–S batteries face significant challenges in achieving good long‐term cycling performance under high sulfur loading and low temperatures. Herein, a kind of bimetallic organosulfur cathode namely Porphyrin(Cu/Fe)‐S‐rGO with high sulfur content (85 wt.%) which benefits from the synergy of the bimetallic atom catalysis and covalently anchored sulfur is designed and prepared for the first time. The results of electrochemical measurements and calculations suggest that the cells with Porphyrin(Cu/Fe)‐S‐rGO cathode exhibit better performance than the cells with corresponding blending cathode Porphyrin(Cu/Fe)/S/rGO and the cell with monometallic cathode Porphyrin(Cu)/S/rGO). Remarkably, the cell with Porphyrin(Cu/Fe)‐S‐rGO cathode can stably cycle for 200 cycles with a maximum capacity of 5.92 mAh cm −2 even under a high sulfur loading of 7.79 mg cm −2 at −20 °C. This study believes that the method of introducing covalent linkages into bimetallic systems offers an innovative solution for the design of high‐performance Li–S batteries under high sulfur loading and low‐temperature conditions.