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.