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

[Display omitted] 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. [ABSTRACT FROM AUTHOR]