Charge storage capacity unequivocally depends on morphology, surface area and porosity of oxide materials. We have in situ grown high surface area, mesoporous, flower and flake-like morphologies of ZnCo2O4 materials on Ni foam in the presence of urea and hexamethylenetetramine. The effect of morphology on the charge storage performance is studied by cyclic voltammetry and chronopotentiometry employing three electrode and two electrode systems. The flower-ZnCo2O4 and flake-ZnCo2O4 electrodes show specific capacitance values of 1657 and 1803 F g−1 at a current density of 1 A g−1, respectively. We find that flower-ZnCo2O4 has higher rate capability and excellent stability under higher current conditions compared to flake-ZnCo2O4. The performance of the flower-ZnCo2O4 material is further tested in a Swagelok solid-state symmetric capacitor for real time applications. This device shows remarkable charge storage behaviour with high specific energy of 40 Wh kg−1 at high specific power of 1016 W kg−1 in the voltage window of 1.2 V. It also shows high rate capability and very good stability. The best performance of ZnCo2O4 material with flower-like morphology is a direct consequence of the availability of large number of inter petal and inter particle voids which facilitate easy transportation of electrolyte ions.
|Journal||Data powered by TypesetElectrochimica Acta|
|Publisher||Data powered by TypesetElsevier BV|