Rational design of free-standing 3D porous MXene/rGO hybrid aerogels as polysulfide reservoirs for high-energy lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries with a high theoretical energy density are attracting increasing attention as promising candidates for next-generation energy storage systems. However, the insulating nature and undesirable shuttle effect of sulfur species dramatically impede their practical applications. Herein, a unique 3D porous Ti₃C₂T_x MXene/rGO (MX/G) hybrid aerogel is rationally designed and applied for the first time as a free-standing polysulfide reservoir to improve the overall performance of Li–S batteries. In this strategy, highly conductive MXene and rGO are integrated into a 3D interconnected porous aerogel structure with efficient 2D polar adsorption interfaces, enabling fast Li⁺/electron transport and strong chemical anchoring of lithium polysulfides as well as enhanced redox reaction kinetics. The robust MX/G aerogel electrodes deliver excellent electrochemical performances including a high capacity of 1270 mA h g⁻¹ at 0.1C, an extended cycling life up to 500 cycles with a low capacity decay rate of 0.07% per cycle, and a high areal capacity of 5.27 mA h cm⁻².