Investigation on electrochemical behaviors of NiCo₂O₄ battery-type supercapacitor electrodes: The role of an aqueous electrolyte

Mesoporous NiCo₂O₄ flower-like structures are prepared successfully by a facile solvothermal route. The electrochemical performance of the as-synthesized products as electrode materials for battery-type supercapacitors is systematically investigated at various concentrations of potassium hydroxide (KOH) aqueous solution by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. NiCo₂O₄ supercapacitor electrode in the 6 M KOH electrolyte delivers high specific capacity (122.5 C g^-1 at 1 A g^-1), excellent rate performance (82.5 C g^-1 at 10 A g^-1) and cycling stability (21.7% capacity loss after 6000 cycles at 2 A g^-1). The results show that KOH electrolyte at high concentrations plays an important role in improving electrochemical performance of NiCo₂O₄ battery-type supercapacitor electrodes.