Electrochemical Synthesis of Nickel Oxide Nanoparticulate Films on Nickel Foils for High-performance Electrode Materials of Supercapacitors

The ultrahigh pseudocapacitive nickel oxide nanoparticulate films on the nickel foils are prepared through a two-step in which nickel hydroxides are electrodeposited on the nickel substrate in 0.08 M Ni(NO3)2 aqueous solution and then they are thermally transformed into uniform nickel oxide nanoparticles. The morphology, structure and electrochemical property of the samples are characterized in detail. The high specific capacitance of 1478 F g–1 with excellent rate capability and long cycle ability is obtained in the case of nickel oxide nanoparticulate film calcined at 250 °C. The loose structure composed of the interconnected nanoparticles as well as the intimate contact between nickel oxide and nickel substrate is responsible for the outstanding capacitive performance of resulting materials. In addition, the especial properties of the electrodeposited nickel hydroxide, such as high water content and lower conversion temperature, are discussed in detail.