Corresponding Author

Zhao-lei LI(zllinju@126.com);
Yan-min GAO(JKDGaoyanmin@163.com)


In this work, hydrothermal reaction and high temperature were used to grow ZnCo2O4 active materials on Ni foam. The crystal stuctures and surface morphlogies of four samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The electrochemical performances were characterized by cyclic voltammetry (CV)、galvanostatic charge/discharge (GCD) testing and electrochemical impedance spectroscopy (EIS) on an electrochemical station. It can be seen that active materials tended to form denser stuctures with an increasing amount of NH4F in the solution system and four different morphologies of ZnCo2O4 were obtained: nanoneedles, thin nanoneedles-clusters, thick nanoneedles-clusters, and lozenge-like bulks.ZnCo2O4 with the thin nanoneedles-clusters morphology held the best electrochemaical performance with the capacitance of 2.77 F·cm-2 at the current density of 5 mA·cm-2. A button asymmetric supercapacitor (ZnCo2O4 -2/NF//AC/NF) assembled with ZnCo2O4 -2/NF and AC/NF exhibited the excellent performance in energy storage. The button asymmetric supercapacitors achieved an energy density of 114.49 μWh·cm-2 at power density of 4001.59 μW·cm-2 and a power density of 24000 μW·cm-2 at energy density of 80 μWh·cm-2.

Graphical Abstract


zinc cobaltate, ammonium fluoride, areal capacitance, asymmetric supercapacitors

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