Performance Study of MXene/Carbon Nanotube Composites for Current Collector‐ and Binder‐Free Mg–S Batteries

The realization of sustainable and cheap Mg‐S batteries depends on significant improvements in cycling stability. Building on the immense research on cathode optimization from Li‐S batteries, for the first time a beneficial role of MXenes for Mg‐S batteries is reported. Through a facile, low‐temperature vacuum‐filtration technique, several novel current collector‐ and binder‐free cathode films were developed, with either dipenthamethylene thiuram tetrasulfide (PMTT) or S(8) nanoparticles as the source of redox‐active sulfur. The importance of combining MXene with a high surface area co‐host material, such as carbon nanotubes, was demonstrated. A positive effect of MXenes on the average voltage and reduced self‐discharge was also discovered. Ascribed to the rich polar surface chemistry of Ti(3)C(2)T(x) MXene, an almost doubling of the discharge capacity (530 vs. 290 mA h g(−1)) was achieved by using MXene as a polysulfide‐confining interlayer, obtaining a capacity retention of 83 % after 25 cycles.