Electrostatic self-assembly of 2-dimensional MXene-wrapped sulfur composites for enhancing cycle performance of lithium–sulfur batteries

Abstract

For lithium–sulfur (Li–S) batteries to be used in practical applications, the low conductivity of elemental sulfur and the shuttle phenomenon need to be overcome together with the preparation of cathode material of a high sulfur content. Herein, we report a two-dimensional (2D) delaminated MXene-wrapped sulfur composite (S@d-MXene) synthesized via facile electrostatic self-assembly. The ultrathin and flexible 2D MXene wrapping of sulfur particles provides a pathway for lithium-ion transport and electron transfer while suppressing the shuttle phenomenon. In addition, the gap between sulfur particle and the d-MXene sheets wrapping its surface provides a buffering space for the volume expansion of the sulfur particle. The Li–S battery with a high sulfur content of 83.8% in S@d-MXene composite provides a capacity of ∼506 mAh g−1 after 500 cycles at a current density of 1C, with a Coulombic efficiency of 99% and an extremely low capacity decay rate (0.047% per cycle).