Controllable synthesis of ZIF-derived Ni_xCo_3−xO₄nanotube array hierarchical structures based on self-assembly for high-performance hybrid alkaline batteries

In this study, a novel Ni_xCo_3−xO₄nanotube array hierarchical structure derived from zeolitic imidazolate frameworks (ZIFs) is grown on Ni foam (Ni_xCo_3−xO₄NAHS/Ni foam) using the template-assisted and self-assembly approach for a high-performance hybrid energy storage device in alkaline solution. The material characteristics of the resultant samples were characterized by XPS, XRD, ICP, SEM, TEM and BET. Due to the unique hollow structure with a large specific surface area and the exposure of large active sites originating from ZIFs, the optimal Ni_xCo_3−xO₄NAHS/Ni foam exhibits substantially enhanced electrochemical properties. The Ni_xCo_3−xO₄NAHS/Ni foam directly acts as an electrode, which provides an excellent specific capacity of 290.48 mA h g⁻¹at 1 A g⁻¹. Subsequently, the corresponding hybrid alkaline batteries that consist of Ni_xCo_3−xO₄NAHS/Ni foam and carbon materials display a highly satisfactory specific capacity of 54.94 mA h g⁻¹at 1 A g⁻¹, a satisfactory long-term stability of 85.47% after 2000 cycles, a maximum energy density of 43.95 W h kg⁻¹and a power density of 8000 W kg⁻¹. This work combines the design of the electronic structure with the optimization of composition, and provides a reference for the application of hybrid rechargeable alkaline batteries (RABs).