Coupling 5 d metallic and conductive Network for promoting polysulfide conversion

The reaction kinetics of lithium-sulfur (Li-S) battery mainly depends on the capture and catalytic conversion efficiency of lithium polysulfide (LiPSs). The unique electron configuration of the 5d metal and the high electrical conductivity of MXene can enhance the interaction between the catalyst and LiPSs. However, the challenge of enhancing the adsorption of LiPSs by regulating the electronic structure of the catalyst with 5d metal and MXene remains unresolved and obscure. In this work, we have developed molybdenum disulfide (MoS2)-tungsten disulfide (WS2) @MXene (MoS2-WS2@MX) heterostructure catalysts for separator coatings in Li-S batteries by introducing W and MXene for the first time. Theoretical calculations demonstrate that the 5 d metallic and conductive MXene coupling effectively modulate the orbital hybridization degree between the catalyst and LiPSs, thereby reducing the energy barrier for LiPSs conversion. Electrochemical test and in situ tests verify the effectiveness of the strategy on the adsorption and conversion of LiPSs. Consequently, the MoS2-WS2@MX based batteries exhibit high initial reversible capacity of 950.3 mAh g−1 and low capacity decay of 0.066 % per cycle over 500 cycles at 2 C, which is superior to most reported catalysts. This study provides a dual regulatory strategy for enhancing catalytic activity, offering valuable insights for the advancement of high-performance Li-S batteries.