Effects of pore widening vs oxygenation on capacitance of activated carbon in aqueous sodium sulfate electrolyte

Zhang, Lixing and Chi, Yuqin and Li, Zhen and Sun, Xiaolei and Gu, Huazhi and Zhang, Haijun and Chen, Yao and Chen, George Zheng (2020) Effects of pore widening vs oxygenation on capacitance of activated carbon in aqueous sodium sulfate electrolyte. Journal of The Electrochemical Society, 167 (4). 040524. ISSN 1945-7111

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Abstract

The commercial activated carbon has a relatively low specific capacitance in the Na2SO4 electrolyte, which hinder the development of asymmetrical supercapacitors with high voltage. Re-activation and oxidative etching methods were applied to change the pore structure of activated carbon, respectively, to study the capacitive behavior of carbon in the Na2SO4 electrolyte. The pore distributions combining with capacitive properties deduce that 0.85 nm is the threshold diameter of the ion-accessible micropores for hydrated Na+ and SO42−. The specific capacitances of both the carbon materials by re-activation and oxidative etching methods are increased by 40 %, in comparison with the commercial activated carbon. The enhanced capacitive performances of the carbon materials were mainly attributed to the increased ion-accessible specific surface area and pseudocapacitance, respectively. The oxidative etching is a more facile and economical method for practice application. Combining with MnO2 as the positive electrode, the asymmetrical supercapacitor with a high voltage of 1.8 V exhibits a maximum specific cell capacitance of 50 F g–1 and specific energy of 22.5 Wh kg–1.

Item Type: Article
Additional Information: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/)
Keywords: activated carbon; re-activation; oxidative etching; sodium sulfate; asymmetrical supercapacitor
Schools/Departments: University of Nottingham Ningbo China > Faculty of Science and Engineering > Department of Chemical and Environmental Engineering
Identification Number: https://doi.org/10.1149/1945-7111/ab75c8
Depositing User: Wu, Cocoa
Date Deposited: 08 May 2020 00:49
Last Modified: 08 May 2020 00:49
URI: http://eprints.nottingham.ac.uk/id/eprint/60534

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