Unlocking Ultrafast‐Kinetics Asymmetric Heterojunction with Multi‐Anionic Redox Chemistry Enables High Energy/Power Density and Low‐Temperature Zinc‐Ion Batteries

Abstract The development of high‐performance Zn‐ion batteries is hindered by sluggish reaction kinetics and inadequate redox activity in conventional vanadium‐based cathodes. Herein, a thermal oxidation phase‐engineering strategy is proposed to construct a comprising VSSe core and oxygen‐enriched VO 2 and V 2 O 5 interfaces triple‐phase heterojunction cathode. This unique architecture leverages a significantly increased specific surface area, which facilitates rapid electrode–electrolyte interactions and boosts pseudocapacitive contributions. This integrated structure, featuring optimized coordination environments and interfaces, promotes synergistic multi‐anionic (S/Se/O) and cationic (V) redox activity and facilitates efficient charge transfer across the interfaces, overcoming intrinsic limitations of capacity and structural instability often observed in single‐phase materials, especially during prolonged cycling. This optimized cathode achieves a record‐high reversible capacity of 432 mAh g −1 at 1 A g −1 , surpassing mild‐oxidized and over‐oxidized VSSe counterparts. Remarkably, it retains 80% capacity after 14 000 cycles at 30 A g −1 under cryogenic conditions of −10 °C, demonstrating unprecedented low‐temperature durability. The structure–function relationship of heterojunction is driven by enhanced p–d orbital hybridization and spin polarization effects at the heterointerfaces, contributing to the improved redox activity and kinetics. This work establishes a design paradigm for engineering multi‐phase heterojunction electrodes with tailored surface area and interfacial properties for next‐generation energy storage systems.