Cobalt–nickel composite films synthesized by chemical bath deposition method as an electrode material for supercapacitors

Cobalt–nickel (Co–Ni) composite thin films were fabricated on copper substrates using a simple chemical bath deposition route in an ammonia-complexed solution containing cobalt chloride and nickel chloride. The structural and morphological properties of the film confirmed that the chemically deposited Co–Ni composites formed in the hydroxide phase and were well covered with irregular shaped nano-platelets. The chemically deposited Co–Ni composite electrode exhibited a maximum specific capacitance of 324 F/g, which was much larger than that of the pristine components. The cyclic voltammetry and charge–discharge test showed that the capacitance of the chemically deposited Co–Ni composite electrode mainly consisted of a pseudocapacitance.