Sulfur Cathodes Based on Conductive MXene Nanosheets for High‐Performance Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries are amongst the most promising candidates to satisfy emerging energy‐storage demands. Suppression of the polysulfide shuttle while maintaining high sulfur content is the main challenge that faces their practical development. Here, we report that 2D early‐transition‐metal carbide conductive MXene phases—reported to be impressive supercapacitor materials—also perform as excellent sulfur battery hosts owing to their inherently high underlying metallic conductivity and self‐functionalized surfaces. We show that 70 wt % S/Ti 2 C composites exhibit stable long‐term cycling performance because of strong interaction of the polysulfide species with the surface Ti atoms, demonstrated by X‐ray photoelectron spectroscopy studies. The cathodes show excellent cycling performance with specific capacity close to 1200 mA h g−1 at a five‐hour charge/discharge (C/5) current rate. Capacity retention of 80 % is achieved over 400 cycles at a two‐hour charge/discharge (C/2) current rate.