In situ synthesis of VS4/Ti3C2Tx MXene composites as modified separators for lithium-sulfur battery

Lithium-sulfur (Li-S) batteries are regarded as highly prospective energy storage devices. However, problems such as low sulfur utilization, poor cycle performance, and insufficient rate capability hinder the commercial development of Li-S batteries. Three-dimensional (3D) structure materials have been applied to modify the separator of Li-S batteries to suppress the diffusion of lithium polysulfides (LiPSs) and inhibit the transmembrane diffusion of Li + . A vanadium sulfide/titanium carbide (VS 4 /Ti 3 C 2 T x ) MXene composite with a 3D conductive network structure has been synthesized in situ by a simple hydrothermal reaction . VS 4 is uniformly loaded on the Ti 3 C 2 T x nanosheets through vanadium-carbon(V-C) bonds, which effectively inhibits the self-stacking of Ti 3 C 2 T x . The synergistic action of VS 4 and Ti 3 C 2 T x substantially reduces the shuttle of LiPSs, improves interfacial charge transfer, and boosts the kinetics of LiPSs conversion, consequently increasing the rate performance and cycle stability of the battery . The assembled battery has a specific discharge capacity of 657 mAh g -1 after 500 cycles at 1C, with a high capacity retention rate of 71%. The construction of VS 4 /Ti 3 C 2 T x composite with a 3D conductive network structure provides a feasible strategy for the application of polar semiconductor materials in Li-S batteries. It also provides an effective solution for the design of high-performance Li-S batteries.