Abstract
Nickel oxide films were synthesized by electrochemical precipitation of Ni(OH)2 followed by heat-treatment in air at various temperatures (200-600 °C). Their structure and electrochemical properties were studied by cyclic voltammetry, X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). XRD results showed that the nickel oxide obtained at 250 °C or above has a crystalline NiO structure. The specific capacitance of the oxide depends on the heat-treatment temperature, showing a maximum value at 300 °C. XAS results revealed that the non-stoichiometric nickel oxide (Ni1-xO) approached the stoichiometric NiO structure with increasing heat-treatment temperature due to the defect healing effect. The defective nature of the nickel oxide could be utilized to improve its specific capacitance for supercapacitor application.
Original language | English |
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Pages (from-to) | 3201-3209 |
Number of pages | 9 |
Journal | Electrochimica Acta |
Volume | 47 |
Issue number | 19 |
DOIs | |
State | Published - 27 Jul 2002 |
Keywords
- Nickel oxide
- Non-stoichiometry
- Pseudocapacitance
- Supercapacitor
- X-ray absorption spectroscopy