Full synergistic effect of hydrothermal NiCo2O4 nanosheets/CuCo2O4 nanocones supported on Ni foam for high-performance asymmetric supercapacitors

Abstract

In this work, a series of NiCo2O4/CuCo2O4 composites were prepared by a two-step hydrothermal method. The optimized NiCo2O4/CuCo2O4 electrode shows more than 5 times area capacitance (4.97 F cm−2) than pure NiCo2O4 at the current density of 1 mA cm−2. The best performance of sample assembled an asymmetric supercapacitor could reach up to 42 F g−1 at the current density of 1 A g−1. In addition, the maximum energy density of 15 W h kg−1 was achieved with the power density of 814 W kg−1. The as-prepared active electrode material also reveals excellent cycling stability with 90.6% capacitance retention after 5000 cycles. These results indicate potential application in developing energy storage devices with high energy density power density.