A Facile Preparation of Zinc Cobaltite (ZnCo 2 O 4 ) Nanostructures for Promising Supercapacitor Applications

Hybrid nanocomposites have shown their excellent potential in energy storage devices particularly in electrochemical supercapacitors to meet the forthcoming demand in the energy sector applications. Novel hybrid composited displayed the dual nature of electrochemical double layer and pseudocapacitive behaviour, which makes them more advantageous in supercapacitor device fabrication. Zinc cobaltite (ZnCo 2 O 4 ) nanostructures have been prepared by precipitation route and the structural, optical and electrochemical properties of the final product were analyzed. X-ray pattern showed the spinal cubic phase structure with fine nano-crystallites. The FTIR and Raman spectrum confirmed the presence of surface functional groups and confirmed the formation of high-quality ZnCo 2 O 4 nanocrystals. XPS and EDX spectrum showed the high purity and good crystallinity nature of the as-prepared ZnCo 2 O 4 nanocrystal. FE-SEM and TEM analysis exhibits the bundle like morphology of the final product. Finally, the as-prepared ZnCo 2 O 4 nanostructure was investigated by cyclic voltammetry (CV), galvanic charge–discharge analysis (GCD) and electrochemical impedance spectroscopy (EIS) to check its suitability. The electrochemical investigation demonstrated the highest capacitance of 159 F g −1 at 2 mA cm −2 in 2 M KOH electrolyte and the long cyclic test showed the 92% initial capacitance retention over 2500 cycles. It reveals/demonstrated that the spinel ZnCo 2 O 4 nanostructures own a promising usage in devices for electrochemical energy storage.