Organosulfur‐Rich Porous Carbon Cathode Enables Soluble‐Polysulfide‐Free and High‐Rate Potassium‐Sulfur Batteries

Abstract

Abstract Potassium–sulfur (K–S) batteries are emerging as one of the most promising candidates for next‐generation energy storage, owing to their high energy density and cost‐effectiveness. However, the severe polysulfide shuttle effect and sluggish redox kinetics of sulfur cathodes remain critical barriers to their practical application. Herein, a class of organosulfur‐rich porous carbon (OSPC) has been developed as a high‐performance cathode for soluble‐polysulfide‐free and high‐rate K–S batteries. The as‐constructed OSPC achieves molecular‐scale confinement of sulfur species within the carbon skeleton via covalent bonding, which enables solid–solid sulfur redox pathways without generation of electrolyte‐soluble polysulfides. Moreover, the conductive carbon skeleton of OSPC with well‐developed porosity can facilitate potassium ion and electron transport within the bulk cathode and significantly improve sulfur redox kinetics. Benefiting from these integrated merits, excellent high rate capability (240.8 mAh g −1 at 5 A g −1 based on the mass of OSPC), long‐term cycling stability (77% retention after 500 cycles at 5 A g −1 ), and remarkable areal capacity (4.5 mAh cm −2 ) can be achieved for the OSPC cathodes. Additionally, the feasibility of synthesizing OSPC from real‐world waste plastics is demonstrated, which offers a dual benefit of alleviating plastic pollution and enabling the fabrication of low‐cost yet high‐performance cathodes for K–S batteries.