Anion‐Vacancy Activated Vanadium Sulfoselenide With In‐Plane Heterostructure Enabling Durable and Wide‐Temperature Zinc‐Ion Batteries

Abstract Zinc‐ion batteries (ZIBs) represent a promising energy‐storage device, which has remarkable merits in terms of cost‐effectiveness, high safety, and environmental sustainability. Transition metal chalcogenides are emerging cathode materials for ZIBs due to their high theoretical capacity and large interlayer spacing. Nevertheless, their application faces critical challenges of sluggish reaction kinetics and huge volume variation. Herein, the anion defect engineering strategy for one‐step in situ anchoring vanadium sulfoselenide on V 2 CT x template (VSSe/V 2 CT x ) in‐plane heterostructure with built‐in anion vacancy is proposed by robust interfacial C─Se─V bonds to overcome these challenges. The incorporation of the Se atom into VS 2 not only changes the metal V atom electronic structure and enhances the intrinsic electrical conductivity of VSSe/V 2 CT x , but also creates more active sites and accelerates the reaction kinetics as confirmed by theoretical calculations and experimental results. Thus, the VSSe/V 2 CT x cathode delivers a high capacity of 114.3 mAh g −1 at 5 A g −1 over 15 000 cycles under cryogenic conditions in quasi‐solid state ZIBs (QSSZIBs). Furthermore, the two QSSZIBs successfully integrated with a hydrogel strain sensor enabling reliable human motion and physiological signal detection, highlighting the promise of VSSe/V 2 CT x cathode for self‐powered wearable healthcare monitoring and management systems.