Vanadium Intercalation into Niobium Disulfide to Enhance the Catalytic Activity for Lithium-Sulfur Batteries

Despitetheir high specific energy and great promisefor next-generationenergy storage, lithium-sulfur (Li-S) batteries sufferfrom polysulfide shuttling, slow redox kinetics, and poor cyclability.Catalysts are needed to accelerate polysulfide conversion and suppressthe shuttling effect. However, a lack of structure-activityrelationships hinders the rational development of efficient catalysts.Herein, we studied the Nb-V-S system and proposed aV-intercalated NbS2 (Nb3VS6) catalystfor high-efficiency Li-S batteries. Structural analysis andmodeling revealed that undercoordinated sulfur anions of [VS6] octahedra on the surface of Nb3VS6 may breakthe catalytic inertness of the basal planes, which are usually theprimary exposed surfaces of many 2D layered disulfides. Using Nb3VS6 as the catalyst, the resultant Li-Sbatteries delivered high capacities of 1541 mAh g(-1) at 0.1 C and 1037 mAh g(-1) at 2 C and could retain73.2% of the initial capacity after 1000 cycles. Such an intercalation-inducedhigh activity offers an alternative approach to building better Li-Scatalysts.