Construction of Cu-Doped Ni-Co-Based Electrodes for High-Performance Supercapacitor Applications

Element doping is an effective method to improve the specific capacity and ion transfer rate of binary metal compounds. In this study, Cu-doped Ni-Cobased electrode materials were synthesized by a hydrothermal process and subsequent annealing treatment. The experimental results show that the nanocone-like Cu-doped Ni-Co-carbonate hydroxides (Ni-Co-Cu CH) with high mass loading and the Cudoped Ni-Co oxide (Ni-Co-Cu oxide) electrode with abundant oxygen defects achieve high area specific capacities of 6.31 F/cm(2) and 6.54 F/cm(2) at 3 A/g, respectively, which are about 2.5 times larger than the area specific capacity of the undoped nanorod-like Ni-Co precursor electrode (2.51 F/cm(2) at 3 A/g). The quasisolid-state asymmetric supercapacitors (ASCs) Ni-Co-Cu CH//AC and Ni-Co- Cu oxide//AC also achieved high energy densities of 36.9 Wh/kg and 42.1 Wh/kg at power densities of 374.2 W/kg and 374.9 W/kg, respectively, which can light up a red light emitting didode for similar to 8 min and similar to 11 min, respectively. Cu doping not only changes the morphology and defect state of a Ni-Co bimetallic compound electrode but also improves its electricity conduction and electrochemical performance. This strategy has important reference significance for the preparation of excellent performance supercapacitor energy storage materials in the future.