Sulfur@Self-assembly 3D MXene hybrid cathode material for lithium-sulfur batteries

High energy density Lithium-Sulfur (Li-S) batteries have attracted significant attention, although their severe energy decay and rate capability loss still hinder their large-scale application. Two-dimensional (2D) MXene materials can immobilize polysulfides via strong chemisorption and physical hinderance. However, MXene nanosheets tend to restack in solution, losing their favorable electronic conductivity due to functional substituents on the surface. In this work, a three-dimensional (3D) MXene material is fabricated with MXene nanosheets and carbon-poly (diallyl dimethyl ammonium chloride) nanoparticles using self-assembly strategy. As the sulfur host, the 3D material not only prevents MXene nanosheets from restacking, but also ensures to provide a framework to confine S and raises the utilization of sulfur. As a result, the sulfur cathode demonstrates a highly reversible specific capacity of 1016.8 mAh g⁻¹ at 0.2 C, excellent rate capability, and long-term cycling stability, with the capacity decay rate of only 0.075% per cycle over 600 cycles at 1 C.