An ether-functionalised cyclic sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors



Neale, Alex R ORCID: 0000-0001-7675-5432, Murphy, Sinead, Goodrich, Peter, Schuetter, Christoph, Hardacre, Christopher, Passerini, Stefano, Balducci, Andrea and Jacquemin, Johan
(2016) An ether-functionalised cyclic sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors. JOURNAL OF POWER SOURCES, 326. pp. 549-559.

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Abstract

A novel cyclic sulfonium cation-based ionic liquid (IL) with an ether-group appendage and the bis{(trifluoromethyl)sulfonyl}imide anion was synthesised and developed for electrochemical double layer capacitor (EDLC) testing. The synthesis and chemical-physical characterisation of the ether-group containing IL is reported in parallel with a similarly sized alkyl-functionalised sulfonium IL. Results of the chemical-physical measurements demonstrate how important transport properties, i.e. viscosity and conductivity, can be promoted through the introduction of the ether-functionality without impeding thermal, chemical or electrochemical stability of the IL. Although the apparent transport properties are improved relative to the alkyl-functionalised analogue, the ether-functionalised sulfonium cation-based IL exhibits moderately high viscosity, and poorer conductivity, when compared to traditional EDLC electrolytes based on organic solvents (propylene carbonate and acetonitrile). Electrochemical testing of the ether-functionalised sulfonium IL was conducted using activated carbon composite electrodes to inspect the performance of the IL as a solvent-free electrolyte for EDLC application. Good cycling stability was achieved over the studied range and the performance was comparable to other solvent-free, IL-based EDLC systems. Nevertheless, limitations of the attainable performance are primarily the result of sluggish transport properties and a restricted operative voltage of the IL, thus highlighting key aspects of this field which require further attention.

Item Type: Article
Uncontrolled Keywords: Electrolyte, Ionic liquid, Sulfonium, Supercapacitor
Depositing User: Symplectic Admin
Date Deposited: 06 Dec 2019 16:04
Last Modified: 19 Jan 2023 00:13
DOI: 10.1016/j.jpowsour.2016.06.085
Open Access URL: https://doi.org/10.1016/j.jpowsour.2016.06.085
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3065223