Synthesis and Characterization of a NiCo(2)O(4)@NiCo(2)O(4) Hierarchical Mesoporous Nanoflake Electrode for Supercapacitor Applications

In this study, we synthesized binder-free NiCo(2)O(4)@NiCo(2)O(4) 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 NiCo(2)O(4)@NiCo(2)O(4) 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 NiCo(2)O(4)@NiCo(2)O(4) 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 NiCo(2)O(4)@NiCo(2)O(4) materials with more uniform architecture for energy storage, in contrast to the traditional galvanostatic deposition methods.