Hierarchical Ni(OH)₂ nanoflake-nanoflower architectures on 3D Ni foam for high-performance supercapacitors

Developing advanced electrode materials that deliver high energy density, exceptional rate capability, and long-term cyclic stability is essential for the next generation of high-performance supercapacitors. Herein, we report a facile one-step hydrothermal approach to directly synthesize binder and additive-free hierarchical nickel hydroxide Ni(OH)₂ nanostructures. These nanostructures primarily consist of nanoflakes and nanoflower-like architectures grown on a three-dimensional nickel foam substrate. This architecture leverages the synergistic advantages of a high surface area, continuous electron transport channels, improved ion accessibility, and robust mechanical integrity. The synthesized Ni(OH)₂/NF electrode shows a high specific capacitance of 982 F g⁻¹ (corresponding to a specific capacity of 393C g⁻¹) at a current density of 1 A g⁻¹ and a cyclic stability, maintaining 86.3 % of its initial capacity after 5000 charge-discharge cycles at a current density 10 A g⁻¹ in 3 M KOH electrolyte. These findings show how morphological engineering can boost electrochemical performance, positioning the Ni(OH)₂ nanoflake-nanoflower architecture as a promising candidate for next-generation energy storage devices. © 2025 Elsevier B.V.