Anchoring Mo₂C nanoparticles on vertical graphene nanosheets as a highly efficient catalytic interlayer for Li-S batteries

In order to accelerate the interconversion between sulfur and lithium polysulfides and suppress the shuttle effect for lithium-sulfur battery system, a multifunctional interlayer is prepared by anchoring Mo₂C nanoparticles on vertical graphene nanosheets (VGSs) grown on short carbon nanofibers (CNFs), which is supported on carbon cloth decorated with VGSs (CG-CFG@Mo₂C). In our strategy, Mo₂C serves as a highly efficient electrocatalyst to expedite the reaction kinetics, while the interlaced framework constructed with VGSs grown on short carbon nanofibers (CFG) provides abundant conductive pathways for charge transfer. As a result, the Li-S batteries with CG-CFG@Mo₂C interlayer show an ultra-high initial specific discharge capacity of 1632 mAh·g⁻¹, reaching a high sulfur utilization rate of 97.4%. Remarkable rate performance with a capacity of 755 mAh·g⁻¹ at a current density of 3C (1C = 1675 mA·g⁻¹) is delivered. Under lean electrolyte dosage of 6 μL·mg⁻¹ with 4.4 mg·cm⁻² sulfur loading, the batteries achieve a high area capacity of 4.8 mAh·cm⁻². These results are more excellent than those batteries only with PP separator and demonstrate that the CG-CFG@Mo₂C interlayer integrating high conductivity, physical barrier, and catalytic activity is of high application potential for high-performance Li-S batteries.