Hierarchically porous NiO microspheres and their nanocomposites with exfoliated carbon as electrode materials for supercapacitor applications

Abstract

In this paper, wet-chemically synthesized hierarchical NiO microspheres and their exfoliated (ExC)-based nanocomposites (NiO/ExC) as electrodes for supercapacitor applications have been reported. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopic (SEM) techniques were used to characterize the as-synthesized products. The study of PXRD revealed that NiO exhibits a cubic phase. Morphological analysis showed a hierarchical micro-spherical structure of mesoporous NiO particles. The as-synthesized hierarchically porous NiO manifested a specific capacitance of 331 F/g with 50% capacitance retention. But, exfoliated carbon (ExC)-based nanocomposite (0.07 g NiO/0.003 g ExC) showed a particular capacitance of 815 F/g at the scan rate of 5 mV/s, with 79% retention in capacitance. High electrical conductivity and larger surface area arising from synergistic effects between NiO and exfoliated carbon resulted in a tremendous electrochemical response of NiO/ExC nanocomposites. The inclusion of the ExC further improves electrical impedance spectroscopic results by facilitating the charge transfer.

GRAPHICAL ABSTRACT

KEYWORDS:

• Microspheres
• exfoliated carbon
• supercapacitor
• specific capacitance
• porous structure

Acknowledgements

The authors acknowledges the financial support of Taif University Researchers Supporting Project number (TURSP-2020/05), Taif University, Taif, Saudi Arabia. Authors are also thankful to the Institute of Chemistry (BJ-Campus), The Islamia University of Bahawalpur and Higher Education Commission (HEC) Pakistan.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Taif University [TURSP-2020/05].