X-ray absorption spectroscopy studies of nickel oxide thin film electrodes for supercapacitors

✍ Scribed by Kyung-Wan Nam; Won-Sub Yoon; Kwang-Bum Kim

• Book ID: 108317829
• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 253 KB
• Volume: 47
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/s0013-4686(02)00240-2

✦ Synopsis

Nickel oxide films were synthesized by electrochemical precipitation of Ni(OH) 2 followed by heat-treatment in air at various temperatures (200 Á/600 8C). 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 8C 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 8C. XAS results revealed that the non-stoichiometric nickel oxide (Ni 1(x O) 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.