Balancing the Adsorption and Conversion of Polysulfides by Co-NC@MoS₂ Catalyst as a Cathode-Integrated Interlayer for...

Lithium-sulfur batteries are considered as a promising energy storage technology due to their high theoretical energy density and cost-effectiveness. However, their practical application is hindered by issues such as active material loss and polysulfide shuttle effect, leading to low energy efficiency and poor cycling stability. Herein, we employed a Co-NC@MoS₂ catalyst featuring a coreshell heterostructurewith an electron-conductive Co-NC core and a layered MoS₂ nanosheet shellas a cathode-integrated interlayer to suppress polysulfide migration and enhance their reutilization. The Co-NC@MoS₂ catalyst demonstrated catalytic activity for converting soluble polysulfides into insoluble end products (S or Li₂S/Li₂S₂), while its strategic placement at the cathodeelectrolyte interface enabled effective retention and reuse of polysulfides within the cathode region. This design mitigated polysulfide accumulation in the electrolyte and minimized shuttle-related polysulfide loss. As a result, lithiumsulfur batteries using a host-free sulfur cathodes and Co-NC@MoS₂ interlayers exhibited a low capacity decay rate of 0.059% per cycle over 300 cycles at 0.2 C substantially outperforming batteries with CNT interlayers (0.172% per cycle). This study here not only presents a rationally designed catalyst for polysulfide adsorption and conversion but also establishes an optimized integration strategy to exploit its performance in lithiumsulfur batteries.