In situ fabrication of porous festuca scoparia-like Ni0.3Co2.7O4 nanostructures on Ni-foam: An efficient electrode material for supercapacitor applications

Abstract

Mixed metal oxides designed by using 3d elements in the Periodic Table are expected to play pivotal role in energy storage. In this work, cetyltrimethyl ammonium bromide (CTAB) assisted hydrothermal homogeneous precipitation method and subsequent calcination are employed to synthesize festuca scoparia-like Ni0.3Co2.7O4 material and compared it with pristine spinel Co3O4 having ultralayered morphology. The specific capacitance (Cs) value for Co3O4 at 1 A g−1 current density is 202 F g−1 which has increased to 396 F g−1 for Ni0.3Co2.7O4 electrode. Further, we have taken two important factors into consideration in fabrication, (i) facile in situ fabrication method, and (ii) desired composition of the active oxide phase on a porous current collector. We have employed same hydrothermal method to grow Ni0.3Co2.7O4 precursor material in situ on Ni foam without using CTAB, and converted it into oxide by heat treatment. The in situ grown Ni0.3Co2.7O4 on Ni foam electrode shows the highest specific capacitance value of 1423 F g−1, which is 3.6 times larger than the value obtained using Ni0.3Co2.7O4 coated on Ni foil at 1 A g−1 current density, and excellent cycling stability up to 4000 cycles. The capacitance loss is only ∼4% at 16 A g−1 and at 32 A g−1. This study confirms the influence of unique features such as current collector, composition, surface area, porosity, and microstructural properties of materials on their electrochemical performance.