Hierarchical CuCo2O4 nanowire@NiCo2O4 nanosheet core/shell arrays for high-performance supercapacitors

Ternary metal oxides have attracted extensive attention for supercapacitor applications due to their enhanced performance compared to their binary counterparts. In this work, 3D CuCo2O4@NiCo2O4 core/shell nanostructures have been synthesized via a two-step method on nickel foam followed by a post annealing process. Morphological characterizations show that the porous CuCo2O4 nanowires are well covered by NiCo2O4 nanosheets. The hybrid electrode is used as a binder-free electrode, showing a high specific capacitance of 2029 F g(-1) (while the areal capacitance is 2.59 F cm(-2)) at the current density of 10 mA cm(-2), higher than the CuCo2O4 electrode. After 4500 cycles, the specific capacitance remains 1548 F g(-1), similar to 80% of the original capacitance. In particular, the hybrid electrode exhibits great rate capability, the hybrid electrode retains 1551 F g(-1) as the current density increases to 30 mA cm(-2), which can be ascribed to the excellent electron transport properties of core/shell CuCo2O4@NiCo2O4 structures.