Conductive few-layered 1T-MoSe2/MXene as a highly-efficient catalyst for accelerating bidirectional sulfur redox kinetics in Li-S batteries

Lithium-sulfur batteries (LSBs) have been regarded as a prospective candidate for next-generation late-model energy storage device due to their merits in gravimetric/ volumetric capacity. However, the practical use of LSBs is still severely limited by the shuttle behavior and extremely slow bidirectional sulfur redox kinetics. Herein, a dual-functional conductive 1T-MoSe2/MXene bidirectional catalyst as a high-efficiency sulfur host was constructed by few-layer 1T-MoSe2 in-situ growth on MXene nano-flakes through one-step solvothermal reaction. Experimental and DFT theoretical analysis reveal that 1T-MoSe2/MXene possess a high electronic conductivity, strong adsorption ability, and abundant active sites, which can provide the strong capture and catalytic conversion ability for LiPSs and uniform deposition and dissolution of Li2S, thus effectively inhibiting the LiPSs shuttle behavior in LSBs. Benefiting from the enhanced bidirectional sulfur redox kinetics and adsorption capacity, the S/1T-MoSe2/MXene cathode delivers a stable long cycling stability with a capacity retention of64.2% (capacity fading per cycle of 0.07%) after 500 cycles at 0.2 C. Furthermore, a high areal capacity of 6.9 mAh cm−2 and good capacity retention of ∼73.1% were obtained after 200 cycles at 0.1 C. This work provides a novel way for the development of dual-functional conductive catalyst to accelerate the catalytic conversion of LiPSs.