Abstract
The rational design and construction of supercapacitor electrode materials with prominent energy and power density play an indispensable role for their potential application in energy storage devices. In this work, NiCo2O4 nanowires grown on Ni foam have been synthesized through a facile hydrothermal approach, revealing a large capacitance and superior cycling stability with 80.3% capacitance retention after 20 000 cycles. The asymmetric supercapacitors are fabricated based on NiCo2O4 nanowire electrodes, which deliver an energy density of 27.4 W h kg(-1) at a power density of 493.2 W kg(-1) and an excellent cycle life with 79.2% capacitance retention after 10 000 cycles.