Electrochemical energy-storage performances of nickel oxide films prepared by a sparking method

Abstract

In this work, nickel oxide (NiO) films have been prepared by a sparking method on flexible chromium/gold coated polyethylene terephthalate substrates and investigated for electrochemical energy-storage applications. Structural characterizations by scanning/transmission electron microscopies, X-ray diffraction, X-ray photoelectron spectroscopy and a UV-vis spectrophotometer reveal that the film comprises polycrstalline NiO nanoparticles with diameters in the range of 3.0–6.0 nm loosely agglomerated into a porous foam-like network. The nanoporous sparked NiO films, exhibit remarkable energy-storage behavior with a high average specific charge capacity of 402.75 C g⁻¹ at a discharge current of 1 A g⁻¹ and a good capacity retention of 88% after 1000 cycles at a high discharge current of 40 A g⁻¹. Thus, the sparking method is a promising alternative route for the preparation of high-performance electrochemical energy-storage devices.