An MXene-based aerogel with cobalt nanoparticles as an efficient sulfur host for room-temperature Na–S batteries

Abstract

High energy density room temperature sodium–sulfur (RT Na–S) batteries are receiving increasing attention as promising energy storage systems. However, the volume expansion of sulfur and the shuttle effect of polysulfides are the biggest obstacles to their development. In this study, a 3D porous aerogel (hybridized by Ti₃C₂T_x MXene and rGO) adhered with cobalt nanoparticles (MG-Co) is applied to RT Na–S batteries. The integration of highly conductive MXene and rGO into a crosslinked aerogel structure can alleviate the volume expansion of sulfur during (dis)charge. Moreover, the polar surface of Ti₃C₂T_x and the catalysis of cobalt particles can boost the strong chemical adsorption and conversion of soluble polysulfides. As a result, RT Na–S batteries assembled with MG-Co@S electrodes deliver a high specific capacity of 705 mA h g⁻¹ at 0.1 C and retain 428 mA h g⁻¹ at 5 C.