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Facile method for synthesis of α-Co(OH)2 and their supercapacitor properties

F.F.M Shaikh (Department of Electronics, Shivaji University, Kolhapur, India)
T.D. Dongale (School of Nanoscience and Biotechnology, Shivaji University, Kolhapur, India)
R.K. Kamat (Department of Electronics, Shivaji University, Kolhapur, India)

Microelectronics International

ISSN: 1356-5362

Article publication date: 1 October 2018

325

Abstract

Purpose

The overall purpose of this research paper largely depends on developing an easy method to synthesis a material suitable for supercapacitor application. This paper includes the synthesis of, α-Co(OH)2, its structural, elemental and morphological properties and its supercapacitor properties.

Design/methodology/approach

Firstly, the electrolyte is prepared using binder free method, then electrodeposition is used to synthesize α-Co(OH)2 at 2 V. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM) are used to study the structural, elemental and morphological characteristics. The supercapacitor properties are investigated by using cyclic voltammetry, charging-discharging graph, stability test and electrochemical impedance spectroscopy (EIS).

Findings

Synthesis of α-Co(OH)2 is a tedious job as the temperature and use of weak base plays an important role. However, throughout electrodeposition, temperature is maintained using a water bath and weak base as the precursor. The presence of nitrate anions shows more interlayer space than that of ß-Co(OH)2 because of which free diffusion of the electrolyte is possible. Sheets structures are more visible in SEM images. Nanosheet like structure is observed in the film and such kind of structure provide higher surface area and higher specific capacitance. Usually, the surface morphology of cobalt hydroxide shows flower-like, spherical and nanocubes particles. The cross-section of the deposited film and it is found to be approximately 100 µm. In the forward and backward scan, oxidation and reduction peaks are clearly visible. However, such a behavior is reported as stable because of no further peaks of oxidation.

Originality/value

XRD and EDS confirms the growth of α-Co(OH)2. SEM images shows the porous nature of the film. Specific capacitance and energy density has been estimated at 5 mV s−1 is 780 F g−1 and 82 W h kg−1, respectively. The film was stable for 600 cycles showing 75 per cent capacitance retention. The voltage drop is 0.02 V for 0.5 A cm−2, indicating low resistance and good conductivity of the film. The specific power is estimated to be 15 W kg−1 for 1 A cm−2. The value of RESR, RCT, CDL and W is 4.83 Ohm, 1.273 Ohm, 0.00233 C and 0.717, respectively. Thus indicating α-Co(OH)2 to be better candidate for supercapacitor applications.

Keywords

Acknowledgements

The authors acknowledge Dr. Habib Pathan for assisting and for his valuable comments that greatly improved the manuscript.

Citation

Shaikh, F.F.M., Dongale, T.D. and Kamat, R.K. (2018), "Facile method for synthesis of α-Co(OH)2 and their supercapacitor properties", Microelectronics International, Vol. 35 No. 4, pp. 220-230. https://doi.org/10.1108/MI-10-2017-0057

Publisher

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Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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