Cobalt and Molybdenum Carbide Nanoparticles Grafted on Nitrogen-Doped Carbon Nanotubes as Efficient Chemical Anchors and Polysulfide Conversion Catalysts for Lithium-Sulfur Batteries

The practical applications of lithium-sulfur (Li−S) batteries are mainly hindered by the shuttle effect of soluble polysulfides and the slow kinetics of polysulfide conversion. Herein, a multi-component material with cobalt and molybdenum carbide nanoparticles grafted on bamboo-like N-doped carbon nanotubes (Co−Mo₂C@NCNTs) is fabricated and applied to modify the separator to suppress polysulfide migration and to promote polysulfide conversion. The uniformly distributed Co and Mo₂C nanoparticles act as both the adsorbent to capture the polysulfides with Co−S and Mo−S bonds by Lewis acid-base interactions and the catalyst to further accelerate the reaction kinetics of polysulfide transformation. Consequently, the Li−S batteries with the Co−Mo₂C@NCNTs-coated separator deliver a high specific capacity of 1324 mAh g⁻¹ at 0.2 C and a capacity decay rate of 0.068 % per cycle at 1 C for 500 cycles. The results suggest the efficient chemical anchoring and catalysis of the multifunctional Co−Mo₂C@NCNTs composite as a feasible method for future large-scale applications of high-performance Li−S batteries.