Molten salt etched Ti3C2Tx MXene for ameliorated electrochemical performances of lithium-sulfur batteries.

MXenes are proved to be ideal sulfur hosts in lithium-sulfur batteries because of their high conductivity and strong polysulfide affinity. However, their synthesis methods are mainly based on the involvement of hazardous HF solution. In this work, Ti₃C₂T_x Mxene (MS-Ti₃C₂T_x) prepared via an environment-friendly molten salt etched method was evaluated as the host material for sulfur. The results indicate that etching temperature is essential to regulate the phase composition and the morphology of MS-Ti₃C₂T_x, thus to determine the electrochemical performances of cathodes with MS-Ti₃C₂T_x. The as-fabricated MS-Ti₃C₂T_x-600/S cathode achieved a much higher sulfur utilization (1089 mAh g⁻¹ at 0.05 °C), an improved rate capacity (712 mAh g⁻¹ under 0.5 °C) and a promoted capacity retention of 76.19% after 100 cycles at 0.1 °C compared with the pristine sulfur cathode. Its promoted electrochemical performances might be ascribed to the prepared MS-Ti₃C₂T_x-600, which not only provides a conductive framework to accelerate electrochemical kinetics, but also supports a strong adsorption to anchor the lithium polysulfides. [ABSTRACT FROM AUTHOR]