Synthesis and electrochemical properties of nanostructured nickel–cobalt oxides as supercapacitor electrodes in aqueous media. (27th April 2015)

• Record Type: Journal Article
• Authors: Chang, Sook‐Keng; Zainal, Zulkarnain; Tan, Kar‐Ban; Yusof, Nor Azah; Wan Yusoff, Wan Mohamad Daud; Prabaharan, S. R. S.
• Is Part Of: International journal of energy research. Volume 39:Number 10(2015:Aug.)
• Page Start: 1366
• Page End: 1377
• Publication Date: 2015-04-27
• Subjects: Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.3339
• Languages: English
• ISSNs: 0363-907X

Abstract

<abstract abstract-type="main" id="er3339-abs-0001"> <title>Summary</title> <p id="er3339-para-0001">Co‐precipitation method was adopted in the preparation of nickel–cobalt oxides for potential application in supercapacitors. The formation of spinel nickel–cobalt oxide, NiCo<sub>2</sub>O<sub>4</sub> started below 400 °C as confirmed by X‐ray diffraction analysis. Pure phase nickel cobaltite with cation ratio of 1:2 (Ni:Co) was obtained at calcination temperature of 400 °C. The spinel phase decomposed gradually until 700 °C. The calcination time for the formation of NiCo<sub>2</sub>O<sub>4</sub> was found to be between 2 to 4 h. The particle size of the prepared sample studied by transmission electron microscopy showed a value of 9.47 nm. The electrochemical properties of the metal oxide were measured in various acidic, neutral and alkaline electrolyte systems (1.0 M HCl, 1.0 M KCl and 1.0 M KOH) by employment of cyclic voltammetry, galvanostatic charge–discharge test and electrochemical impedance spectroscopy. Ideal capacitor behaviour with the largest operating voltage of 1.0 V and good electrochemical stability were observed in NiCo<sub>2</sub>O<sub>4</sub> using neutral KCl aqueous electrolyte. Meanwhile, the prepared sample displayed the highest surface redox activity in 1.0 M KOH alkaline electrolyte but showed the lowest electrochemical performance in acidic electrolyte. At the current density of 0.5 A g<sup>−1</sup>, 1.0 M HCl, 1.0 M KCl and 1.0 M KOH gave specific capacitance values of 3.8, 41.9 and 249.8 F g<sup>−1</sup> respectively. Copyright © 2015 John Wiley & Sons, Ltd.</p> </abstract>