Please use this identifier to cite or link to this item: doi:10.22028/D291-28899
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Title: Reduced Faradaic Contributions and Fast Charging of Nanoporous Carbon Electrodes in a Concentrated Sodium Nitrate Aqueous Electrolyte for Supercapacitors
Author(s): Abbas, Qamar
Gollas, Bernhard
Presser, Volker
Language: English
Title: Energy Technology
Volume: 7
Issue: 9
Publisher/Platform: Wiley-Blackwell
Year of Publication: 2019
Publikation type: Journal Article
Abstract: The Faradaic processes related to electrochemical water reduction at the nanoporous carbon electrode under negative polarization are reduced when the concentration of aqueous sodium nitrate (NaNO3) is increased or the temperature is decreased. This effect enhances the relative contribution of ion electrosorption to the total charge storage process. Hydrogen chemisorption is reduced in aqueous 8.0 m NaNO3 due to the low degree of hydration of the Na+ cation; consequently, less free water is available for redox contributions, driving the system to exhibit electrical double‐layer capacitive characteristics. Hydrogen adsorption/desorption is facilitated in 1.0 m NaNO3 due to the high molar ratio. The excess of water shifts the local pH in carbon nanopores to neutral values, giving rise to a high overpotential for dihydrogen evolution in the latter. The dilution effect on local pH shift in 1.0 m NaNO3 can be reduced by decreasing the temperature. A symmetric activated carbon cell assembled with 8.0 m NaNO3 exhibits a high capacitance and coulombic efficiency, a larger contribution of ion electrosorption to the overall charge storage process, and a stable capacitance performance at 1.6 V.
DOI of the first publication: 10.1002/ente.201900430
URL of the first publication: https://onlinelibrary.wiley.com/doi/full/10.1002/ente.201900430
Link to this record: hdl:20.500.11880/27802
http://dx.doi.org/10.22028/D291-28899
ISSN: 2194-4288
2194-4296
Date of registration: 17-Sep-2019
Faculty: NT - Naturwissenschaftlich- Technische Fakultät
Department: NT - Materialwissenschaft und Werkstofftechnik
Collections:UniBib – Die Universitätsbibliographie

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