Design and preparation of Cu-doped NiCo2O4 nanosheets with intrinsic porosities for symmetric supercapacitors

Abstract The Cu-doped NiCo2O4 nanosheets with intrinsic porosities were designed and prepared by the density functional theory and hydrothermal method. Cu-doping can increase the electron states near Fermi level and partially delocalized charge, indicating the enhanced metallic properties of NiCo2O4. The intrinsic porosities can ensure a rapid electron transfer and ion diffusion during the electrochemical charge/discharge process. As a three-electrode cell, the Cu-NiCo2O4 electrode gained the capacitance retention of 78.8% after 3000 cycles at 1 A g-1. The symmetric supercapacitor revealed the energy density of 20.5 W h kg-1 at the power density of 558.5 W kg-1. The capacitance retention can be remained about 94.6% after 3000 cycles at 3 A g-1.