Conductive Carbon Fibrous Interlayer Embedded with MoS2@CNT Composites for Mitigating Polysulfide Shuttling by Absorption and Catalysis in Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries (LSBs) have emerged as promising energy storage systems due to their high energy density, low cost, and environmental friendliness. However, the “shuttle effect” of lithium polysulfides (LiPSs) leads to rapid capacity decay and poor cycle stability in LSBs, hindering further development and application of LSBs. In addition, it is difficult for existing strategies to provide effective adsorption and catalytic properties for polysulfides while simultaneously ensuring rapid ion transport. To address this issue, a composite film made of carbon fibers embedded with MoS₂@CNT is proposed as an interlayer between the separator and the cathode. Results show that such a conductive interlayer can effectively capture LiPSs and catalyze their transformation. The as-assembled LSBs deliver an initial discharge-specific capacity of 1179.03 mAh/g at 0.5 C, and a capacity of 1086.33 mAh/g remains after 100 cycles. During long-term cycling tests, the LSBs show discharge capacities of 463.13 mAh/g with a decay rate per cycle of 0.07% after 500 cycles at 3 C, representing a reduction of 0.06% compared to that of commercial batteries (0.13%). This work demonstrates the potential of the independent conductive interlayer design of carbon fibrous films embedded with MoS₂@CNT composites for enhancing battery performance. The film can not only provide an efficient conductive network for accelerating ion transport but also suppress the shuttle effect and catalyze the transformation of LiPSs, boosting electrochemical reaction kinetics.