Structure-designed synthesis of hierarchical NiCo2O4@NiO composites for high-performance supercapacitors.

The design of multicomponent electrode materials is attractive for advanced supercapacitors due to synergistic and multifunctional effects among different active materials. We reported here a structure-designed synthesis strategy to controllably fabricate hierarchical NiCo2O4@NiO composites on carbon fiber paper. The hierarchical structure with NiCo2O4 core and NiO shell provided more active sites for ion transportation and storage to improve utilization rate of electrode materials, enhancing the specific capacitance and rate performance. As an ideal electrode material for supercapacitors, the NiCo2O4@NiO electrode exhibit high specific capacitance (1188 F/g at 2 A/g), excellent rate capability with ∼85% capacitance retained at 10 A/g, and compelling cycling performance (∼106.8% of the initial capacitance retention over 7000 cycles). The present work demonstrated a structure-designed strategy to construct high-performance multicomponent electrode materials for supercapacitors.