Synthesis and characterization of a nico₂o₄@nico₂o₄ hierarchical mesoporous nanoflake electrode for supercapacitor applications

In this study, we synthesized binder‐free NiCo₂O₄@NiCo₂O₄ nanostructured materials on nickel foam (NF) by combined hydrothermal and cyclic voltammetry deposition techniques followed by calcination at 350 °C to attain high‐performance supercapacitors. The hierarchical porous NiCo₂O₄@NiCo₂O₄ structure, facilitating faster mass transport, exhibited good cycling stability of 83.6% after 5000 cycles and outstanding specific capacitance of 1398.73 F g⁻¹ at the current density of 2 A∙g⁻¹, signifying its potential for energy storage applications. A solid‐state supercapacitor was fabricated with the NiCo₂O₄@NiCo₂O₄ on NF as the positive electrode and the active carbon (AC) was deposited on NF as the negative electrode, delivering a high energy density of 46.46 Wh kg⁻¹ at the power density of 269.77 W kg⁻¹. This outstanding performance was attributed to its layered morphological characteristics. This study explored the potential application of cyclic voltammetry depositions in preparing binder‐free NiCo₂O₄@NiCo₂O₄ materials with more uniform architecture for energy storage, in contrast to the traditional galvanostatic deposition methods.