Facile synthesis of ZnCo sub(2)O sub(4) nanowire cluster arrays on Ni foam for high-performance asymmetric supercapacitors

ZnCo sub(2)O sub(4) nanowire cluster arrays (NWCAs) were directly grown on Ni foam viaa facile hydrothermal method. The resulting products were analyzed by using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The ZnCo sub(2)O sub(4) NWCAs on Ni foam were directly used as integrated electrodes for supercapacitors and exhibited a high specific capacitance of 4.05 F cm super(-2) at 20 mA cm super(-2) (1620 F g super(-1) at 8 A g super(-1)) in 3 M KOH aqueous solution, and an excellent cycling ability at various current densities up to 100 mA cm super(-2) (40 A g super(-1)); 90% of the initial capacitance remained after 6000 cycles. Moreover, the asymmetric supercapacitor had a high energy density of 41.00 W h kg super(-1) at a power density of 384 W kg super(-1) and 16.63 W h kg super(-1) at a high power density of 2561 W kg super(-1). Such excellent rate properties and superior cycling life suggest that ZnCo sub(2)O sub(4) NWCAs can not only be applied in high energy density fields, but also used in high power density applications.