Uniformly Controlled Treble Boundary Using Enriched Adsorption Sites and Accelerated Catalyst Cathode for Robust Lithium–Sulfur Batteries

Rechargeable lithium–sulfur batteries (LSBs) are recognized as a promising candidate for next-generation energy storage devices because of their high theoretical specific capacity and energy density. However, the insulating of sulfur, Li₂S₂/Li₂S, and the shuttling effect of high order lithium polysulfides (LiPSs) hinder its practical applications. Herein, a heterostructure is explored to enhance the conversion reaction kinetics and adsorption ability of LiPSs. By rationally designing a conductive carbon framework and polar metal sites, both experimental and theoretical results show strong adsorption abilities for dissolved LiPSs and promote the conversion reaction rate. A CoSe₂/Co₃O₄@NC-CNT/S cathode shows an excellent rate performance (≈1457 mAh g⁻¹ at 0.1 C and still retains ≈688 mAh g⁻¹ at a high rate of 5 C). When performing charge–discharge in long-term stability at 2 C, the CoSe₂/Co₃O₄@NC-CNT/S cathode delivers a high initial specific capacity of ≈780 mAh g⁻¹ and retains ≈602 mAh g⁻¹ after 500 cycles with an excellent Coulombic efficiency of ≈95.4%. Remarkably, the battery can entirely operate even at a very high sulfur loading of ≈10.1 mg cm⁻² and lean electrolyte condition. This work emphasizes a new strategy to rationally design heterostructures that can encourage the industrial application of LSBs.