Electrochemical investigation of copper/nickel oxide composites for supercapacitor applications

Abstract

Micro-branched copper/nickel oxide composites were synthesized in this article by using two simple and continuous electroplating processes, chemical oxidation, and annealing process. Morphology and electrochemical properties of the as prepared sample were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), and electrochemical measurements. The SEM images indicated that the as prepared micro branched copper/nickel oxide composites had porous and branched microstructure, which derived from the rapid generation and dispersion of the hydrogen bubbles while electroplating copper under the high current density and the well-formed nickel layer on the copper surface. The measured maximum specific capacitance was 296.2 F/g at the scan rate of 10 mV/s. In addition, cyclic voltammetric curves indicated good ions accessibility and charge storage ability of the prepared composite material, which was mainly due to its high surface area, novel branch-like microstructure and low inner resistance (2.05 Ω). Moreover, the developed composite material exhibited long cycle life along with 97% specific capacitance retained after 500 cycles. The enhancement of the electrochemical performance also benefited from good adhesion and low contact resistance between the copper and nickel layers.