Regulating Extra-Layer Ion Channels in the Conductive VO Hydrogel Cathode.

High-power energy storage devices rely on the synergistic coordination of ion and electron transport. Here, an extra-layer channels engineering strategy is presented for developing high power and energy density cathode materials for aqueous zinc batteries (AZIBs). This approach utilizes a cation-induced self-assembly process to form conductive hydrogels with extra-layer channels by adding diverse cations (Li, Na, K, Mg, Zn, Al, and NH ) into the carbon nanotubes (CNTs) ink dispersed hydrated VO (h-VO) nanowires. The cations bridge h-VO nanowires and create self-assembly network on the CNT surfaces, providing extra-layer ion channels beyond the intrinsic interlayer of h-VO. These external channels exhibit distinct properties depending on the cations, significantly influencing the performance of VO hydrogel cathode for AZIBs. Larger cations reduce Zn migration resistance enhancing diffusion kinetics; smaller cations strengthen the M─O bond, improving structural stability. For instance, K-VO/CNT demonstrates an initial specific capacity of up to 618 mAh g at 0.2 A g and retains a capacity of 248 mAh g even at 20 A g. In contrast, the Zn-VO/CNT maintains excellent cycling stability, with 230 mAh g after 700 cycles at 1 A g. This offers a versatile platform for tailoring ion transport channels in hydrogel cathodes for ZIBs.