Co3O4@NiCo2O4 microsphere as electrode materials for high-performance supercapacitors

In this work, hierarchical Co3O4@NiCo2O4 microspheres composed of nano particles grown on nickel foam as supercapacitor electrode material were designed by a hydrothermal route, following an ultrasonic-assisted process. The introduction of moderate amounts NiCo2O4 in Co3O4 can decrease charge transfer resistance and enhance the transfer of electrons and ions. Therefore, Co3O4@NiCo2O4 (4:1) shows an excellent specific capacitance of 879.4 F g−1 at 10 A g−1, and the capacitance retention maintains 81.2% of its first capacitance after 3000 cycles, indicating a high cycling durability and outstanding fast charge-discharge performance. The outstanding property exhibits that the hierarchical Co3O4@NiCo2O4 (4:1) microsphere has tremendous application potential in supercapacitors.