Efficient polysulfides conversion on Mo2CTx MXene for high-performance lithium–sulfur batteries

The severe shuttle effect and sluggish redox kinetics of polysulfides hinder the application of lithium–sulfur batteries. Herein, delaminated Mo2CTx MXene nanosheets are derived by chemical etching approach and further applied as a sulfur host for sulfur spheres (S@Mo2CTx). In the MXene encapsulated architecture, the external MXene nanosheets not only immobilize the soluble polysulfides by strong chemical adsorption but also efficiently catalyze the liquid–liquid conversion and liquid–solid nucleation process of lithium polysulfides. In addition, the S@Mo2CTx electrode delivered fast charge and lithium-ion transport due to the superior electric conductivity and low lithium-ion diffusion energy barrier of MXene nanosheets. As a result, the S@Mo2CTx electrode exhibits a high reversible capacity of 918 mAh·g−1 at 1.0C with good cycling stability and a high areal capacity of 7.0 mAh·cm−2 with sulfur loading of 7.4 mg·cm−2 under a lean electrolyte condition.