Cobalt Nanoparticles Loaded on MXene for Li-S Batteries: Anchoring Polysulfides and Accelerating Redox Reactions.

Catalysis is regarded as an effective strategy to fundamentally increase sulfur utilization, accelerating the kinetics of the transformation between lithium polysulfides (LiPSs) and lithium sulfide (Li S) on a substrate. However, the intermodulation of catalysts and sulfur species is elusive, which is limited to the comprehensive analysis of electrochemical performance in the dynamic reaction process. Herein, cobalt nanoparticles loaded on MXene nanosheets (Co/Ti C) are selected as sulfur hosts and the representative catalyst. By combining ex situ electrochemical results and interfacial structural chemical monitoring, the catalysis process of Co/Ti C toward LiPSs conversion is revealed, and the outstanding performance originates from the optimization of chemical adsorption, catalytic activity, and lithium-ion transfer behaviors, which is based on electronic/ion modulation and sufficient interfaces among catalysts and electrolyte. This work can guide the construction of electronic modulation at triple-phase interface catalysis to overcome the shuttle effect and facilitate sulfur redox kinetics in Li-S batteries.