Customizing MXene@CoSe₂ for cathode host of lithium–sulfur batteries to promote the redox kinetics of lithium polysulfides

The problematic polysulfide shuttle effect, slow redox kinetics of lithium polysulfides conversion, and low conductivity impede the prospects of lithium-sulfur battery applications. To address these issues, a unique rod-like CoSe₂ nanoparticle decorated flake MXene (MXene@CoSe₂) emerges as a promising host material for the design of advanced batteries. Here, we use a hydrothermal synthesis strategy to grow CoSe₂ nanorods in situ on the surface of flake MXene. By comparing the electrochemical properties of MXene@CoSe₂ electrodes with Mxene@Co electrodes, it is determined that the MXene@CoSe₂ electrode could adsorb lithium polysulfides more efficiently while accelerating the redox kinetics of lithium polysulfides to suppress the shuttle effect. As a result, the initial specific capacity at Mxene@CoSe₂ cathode could reach 1, 050.6 mAh g⁻¹ at 0.1 C, which reaches 560.8 mAh g⁻¹ after 100 cycles and remains at 492.9 mAh g⁻¹ after 1, 000 cycles at 1 C, with a low average decay rate of 0.302% per cycle.