Electrochemical supercapacitor development based on electrodeposited nickel oxide film

A nickel oxide (NiO) electrode has been synthesized electrochemically, which is envisaged for supercapacitor application. The structural, morphological, and phase-purity confirmation studies of NiO films were undertaken using X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy, and contact angle measurements. Films of NiO were amorphous in phase, as there were no reflecting planes in the X-ray diffraction pattern. The presence of characteristic bands in FTIR and X-ray photoelectron spectroscopy analysis corroborated the NiO structure. The NiO film surface was smooth with very fine elongated particles (∼70 nm) and hydrophilic in character (57°). The supercapacitive performance of an NiO electrode tested using cyclic voltammetry measurement in 0.5 M Na₂SO₄ electrolyte within the potential range of -1.2 to +1.2 V demonstrated a specific capacitance as high as 458 F g^-1 at 5 mV s^-1. The obtained specific energy, specific power and Coulomb efficiency of NiO electrode were 10.90 W h kg^-1, 0.89 kW kg^-1, and 98%, respectively.