Immobilizing Polysulfides with MXene-Functionalized Separators for Stable Lithium-Sulfur Batteries

Lithium sulfur batteries have attracted increasing attention as one of the most promising candidates for next-generation energy storage systems. However, the poor cycling performance and the low utilization of sulfur greatly hinder its practical applications. Here we report the improved performance of lithium sulfur batteries by coating Ti3C2Tx MXene nanosheets (where T stands for the surface termination, such as -O,-OH, and/or -F) on commercial "Celgard" membrane. In favor of the ultrathin two-dimensional structure, the Ti(3)c(2)T(x) MXene can form a uniform coating layer with a minimum mass loading of 0.1 mg cm(-2) and a thickness of only 522 nm. Owing to the improved electric conductivity and the effective trapping of polysulfides, the lithium-sulfur batteries with MXene-functionalized sepailtors exhibit superior performance including high specific capacities arid cycling stability.