N-doped carbon/Ti3C2Tx MXene free-standing films as sulfur hosts for Li–S batteries

Abstract

The performance of sulfur-based cathodes is restricted by the poor conductivity of sulfur and the shuttle effect of lithium polysulfides (LiPSs). Herein, an effective N-doped carbon/Ti₃C₂T_x (NC/Ti₃C₂T_x) free-standing architecture was designed as a sulfur host for achieving high sulfur loadings, considerable electronic conductivity and good LiPS trapping ability to suppress the shuttle effect. Consequently, an excellent electrochemical performance was achieved for the NC-S/Ti₃C₂T_x freestanding structure with a 38% increase in capacity compared with the counterpart electrode of slurry-coated NC-S/Ti₃C₂T_x. Moreover, the NC-S/Ti₃C₂T_x freestanding structure exhibits a high capacity of 1156 mA h g⁻¹ at 0.1C and a high capacity retention of 79.5% after 100 cycles. Moreover, this architecture enabled high sulfur loadings, and thus, a high areal capacity of 3.41 mA h cm⁻² was obtained.