Novel synthesis and characterization of ZnCo2O4 nanoflakes grown on nickel foam as efficient electrode materials for electrochemical supercapacitors

ZnCo2O4 nanoflakes were directly grown on Ni foam via a two-step facile strategy, involving cathodic electrolytic electrodeposition (ELD) method and followed by a thermal annealing treatment step. The results of physical characterizations exhibit that the mesoporous ZnCo2O4 nanoflakes have large electroactive surface areas (138.8 m2 g−1) and acceptable physical stability with the Ni foam, providing fast electron and ion transport sites. The ZnCo2O4 nanoflakes on Ni foam were directly used as integrated electrodes for supercapacitors and their electrochemical properties were measured in 2 M KOH aqueous solution. The ZnCo2O4 nanoflake electrode exhibits a high capacitance of 1781.7 F g−1 at a current density of 5 A g−1 and good rate capability (62% capacity retention at 50 A g−1). Also, an excellent cycling ability at various current densities from 5 to 50 A g−1 was obtained and 92% of the initial capacitance maintained after 4000 cycles. The results demonstrate that the proposed synthesis route is cost-effective and facile and can be developed for preparation of electrode materials in other electrochemical supercapacitors.