Investigation on the electrochemical properties of mesoporous Zn_0.2Ni_0.05Co_0.5O microspheres for supercapacitors

ABSTRACT

We report the electrochemical performances of mesoporous Zn_0.2Ni_0.05Co_0.5O microspheres, synthesised through a simple hydrothermal route for supercapacitor application. Structural properties were studied by using powder X-ray diffraction, thermo-gravimetric, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy analyses. The crystal lattice parameter of mesoporous Zn_0.2Ni_0.05Co_0.5O microspheres (MPS1) is found to be 8.108 Å with an average crystallite size of 31 nm. The electron microscopic study reveals the sphere-shaped microstructures with porous nature. The specific surface area of MPS1 found to be 54 m² g⁻¹ with bimodal average pore diameter of 4 and 12 nm from N₂ absorption-desorption data. The electrochemical properties of MPS1 electrode were investigated by different experimental measurements in three-electrode configuration. The specific capacity of the electrode found to be 270 C g⁻¹ (675 F g⁻¹) at 4.08 A g⁻¹ and 1253 C g⁻¹ (2088 F g⁻¹) at 2 mV s⁻¹. The charge storage mechanism was explicated via Trasatti plotting approach. It reveals the major ratio of the charges stored in the outer surface of MPS1. Furthermore, the electrochemical long-term cycling stability of the electrode is examined by the galvanostatic charge-discharge cycle test and found an excellent cycling retention about 97% of its initial value after 1000 cycles.

KEYWORDS:

• Spinel structure
• electrochemical performance
• supercapacitor
• cyclic stability

Acknowledgments

The financial support from UGC-DAE-CRS, Government of India (grant no. CRS-KN/CRS-119/2018-19/1057) is gratefully acknowledged. VK thanks to TEQIP-III (MHRD), for providing a research fellowship.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary Material

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