Heterostructures\nof MXene and Graphene as Cathode\nHosts Improving Anchoring and Reaction Dynamics for Li–S Batteries

Lithium–sulfur batteries have attracted great\nenthusiasm\nbecause of the high specific capacity and energy density, while the\napplication is still limited by the “shuttle effect”\nof polysulfides and slow reaction dynamics. Here, different MXene-graphene\nheterostructures were used as sulfur cathode hosts, and the electrochemical\nperformances were studied via first-principles simulation. Compared\nwith a single MXene or graphene component, the MXene side of the heterostructure\ncould more effectively anchor lithium polysulfides and inhibit the\nshuttle effect. However, more importantly, Ti<sub>2</sub>CS<sub>2</sub>-graphene heterostructures could more effectively promote the sulfur\nreduction reaction during the discharging process and reduce the diffusion\nbarrier of Li<sup>+</sup>/decomposition barrier of Li<sub>2</sub>S\nduring the charging process, which is beneficial for improving the\nsluggish dynamics in Li–S batteries. This work suggests that\nTi<sub>2</sub>CS<sub>2</sub>-graphene heterostructures could be used\nas potential cathode hosts and provide theoretical guidelines for\nthe design of cathode hosts for Li–S batteries.