VO₂(p)-V₂C(MXene) Grid Structure as a Lithium Polysulfide Catalytic Host for High-Performance Li-S Battery

Extensive efforts have been devoted to improving the cycling stability and reversibility of lithium-sulfur batteries. However, unsolved challenges and difficulties still remain in suppressing the shuttle effect, improving the conductivity and structural stability of sulfur cathodes. Here, we report a three-dimensional (3D) grid heterostructure VO₂(p) (paramontroseite-VO₂) nanorod cluster growing on the surface of two-dimensional V₂C (MXene) nanosheets as a high-performance catalytic host for sulfur cathodes. The results of first-principles calculation demonstrate that VO₂(p) nanorods can synergize with V₂C to enhance the adsorption capacity of host for lithium polysulfides in this host structure and reduce the redox reaction barrier in the conversion of polysulfides to short-chain sulfides. In addition, the high specific surface area and structural stability of the host material can increase the redox reaction kinetics and cyclic reversibility of the electrode. The VO₂(p)-V₂C/S cathode exhibits outstanding electrochemical performance and excellent reversible discharge capacity (1250 mAh·g^-1 at 0.2C), long-term cycling stability (69.1% retention at 2C after 500 cycles), and high sulfur loading cycling capacity (initial areal capacity of 9.3 mAh·cm^-2 at 0.2C for 200 cycles). Our research provides a valuable reference for the design of high-performance cathode structures with high sulfur loading.