Performance evaluation of galvanostatically deposited nickel oxide electrode for electrochemical supercapacitors

Nanostructured nickel oxide (NiO) electrode has been prepared using electrochemical work station operated on galvanostatic mode in supercapacitor application. Crystalline cubic structure and nanoplate-type of morphology of synthesized NiO electrode was confirmed from X-ray diffraction and scanning electron microscopy analysis respectively. The wettability study was tested by contact angle measurement, which reveals hydrophilic nature of NiO electrode with contact angle of 59°. The presence of nickel and oxygen characteristic bands in EDAX and XPS spectrum has corroborated the NiO formation. The supercapacitive properties of NiO electrode were tested by cyclic voltammogram (CV) in 1 M aqueous Na₂SO₄, KOH, NaOH electrolytes within the potential range of − 1.1 to 0.9 V, 0 to 0.4 V and − 1.2 to 0.4 respectively. The CV study demonstrates maximum specific capacitance of 481.16 Fg^− 1 for 1 M Na₂SO₄. The obtained specific power, specific energy and coulombic efficiency values of NiO electrode are 19.48 kW kg^− 1, 60.12 Whkg^− 1, and 92.31%, respectively. In the meantime it exhibited excellent cycle life time with 92.3% specific capacitance kept after 1000 cycles. These results imply that NiO electrode is promising candidate for upcoming thin film supercapacitors and other microelectronic constructions.