The University of Southampton
University of Southampton Institutional Repository

Phase behaviour and conductivity of supporting electrolytes in supercritical difluoromethane and 1,1-difluoroethane

Phase behaviour and conductivity of supporting electrolytes in supercritical difluoromethane and 1,1-difluoroethane
Phase behaviour and conductivity of supporting electrolytes in supercritical difluoromethane and 1,1-difluoroethane
We present investigations into a variety of supporting electrolytes and supercritical fluids probing the phase and conductivity behaviour of these systems and show that they not only provide sufficient electrical conductivity for an electrodeposition bath, but match the requirements imposed by the different precursors and process parameters, e.g. increased temperature, for potential deposition experiments. The two supercritical fluids that have been explored in this study are difluoromethane (CH2F2) and 1,1-difluoroethane (CHF2CH3). For CH2F2, the phase behaviour and electrical conductivity of eight ionic compounds have been studied. Each compound consists of a cation and an anion from the selected candidates i.e. tetramethylammonium ([N(CH3)4]+), tetrabutylammonium ([N(nC4H9)4]+), 1-ethyl-3-methylimidazolium ([EMIM]+) and 1-butyl-3-methylimidazolium ([BMIM]+) for cations, and tetrakis(perfluoro-tert-butoxy)aluminate ([Al(OC(CF3)3)4]?), chloride (Cl?), trifluoromethyl sulfonimide ([NTf2]?) and tris(pentafluoroethyl)trifluorophosphate ([FAP]?) for anions. For CHF2CH3, [N(nC4H9)4][BF4] and [N(nC4H9)4][B{3,5-C6H3(CF3)2}4] have been investigated for comparison with the previously measured solubility and conductivity in CH2F2. We have found that [N(nC4H9)4][Al(OC(CF3)3)4], [N(nC4H9)4][FAP] and [N(CH3)4][FAP] have much higher molar conductivity in scCH2F2 at similar conditions than [N(nC4H9)4][BF4], a widely used commercial electrolyte. Additionally, scCHF2CH3 shows potential for use as the solvent for supercritical fluid electrodeposition, especially at high temperatures since high density of this fluid can be achieved at lower operating pressures than similar fluids that can be used to produce electrochemical baths with comparable conductivity.
1463-9076
14359-14369
Han, Xue
6fe07b0a-df76-4bc4-b9b7-8b3b4bbad3ab
Ke, Jie
e4b531d4-7642-4367-9a4e-d06f126c2599
Suleiman, Norhidayah
0cc75d4d-fc72-489c-9c3a-a97d6a78419f
Levason, William
e7f6d7c7-643c-49f5-8b57-0ebbe1bb52cd
Pugh, David
9ec61267-ae4d-40d8-bebf-0d603e2588d3
Zhang, Wenjian
1f80ac5e-d4c2-4720-b19e-be700cd411e7
Reid, Gillian
37d35b11-40ce-48c5-a68e-f6ce04cd4037
Licence, Peter
5151abbd-273d-4ede-9ad9-f67fca6a8afc
George, Michael W.
09040935-b1da-4a63-ad2e-5ba29e39f80a
Han, Xue
6fe07b0a-df76-4bc4-b9b7-8b3b4bbad3ab
Ke, Jie
e4b531d4-7642-4367-9a4e-d06f126c2599
Suleiman, Norhidayah
0cc75d4d-fc72-489c-9c3a-a97d6a78419f
Levason, William
e7f6d7c7-643c-49f5-8b57-0ebbe1bb52cd
Pugh, David
9ec61267-ae4d-40d8-bebf-0d603e2588d3
Zhang, Wenjian
1f80ac5e-d4c2-4720-b19e-be700cd411e7
Reid, Gillian
37d35b11-40ce-48c5-a68e-f6ce04cd4037
Licence, Peter
5151abbd-273d-4ede-9ad9-f67fca6a8afc
George, Michael W.
09040935-b1da-4a63-ad2e-5ba29e39f80a

Han, Xue, Ke, Jie, Suleiman, Norhidayah, Levason, William, Pugh, David, Zhang, Wenjian, Reid, Gillian, Licence, Peter and George, Michael W. (2016) Phase behaviour and conductivity of supporting electrolytes in supercritical difluoromethane and 1,1-difluoroethane. Physical Chemistry Chemical Physics, 18 (21), 14359-14369. (doi:10.1039/c6cp00466k).

Record type: Article

Abstract

We present investigations into a variety of supporting electrolytes and supercritical fluids probing the phase and conductivity behaviour of these systems and show that they not only provide sufficient electrical conductivity for an electrodeposition bath, but match the requirements imposed by the different precursors and process parameters, e.g. increased temperature, for potential deposition experiments. The two supercritical fluids that have been explored in this study are difluoromethane (CH2F2) and 1,1-difluoroethane (CHF2CH3). For CH2F2, the phase behaviour and electrical conductivity of eight ionic compounds have been studied. Each compound consists of a cation and an anion from the selected candidates i.e. tetramethylammonium ([N(CH3)4]+), tetrabutylammonium ([N(nC4H9)4]+), 1-ethyl-3-methylimidazolium ([EMIM]+) and 1-butyl-3-methylimidazolium ([BMIM]+) for cations, and tetrakis(perfluoro-tert-butoxy)aluminate ([Al(OC(CF3)3)4]?), chloride (Cl?), trifluoromethyl sulfonimide ([NTf2]?) and tris(pentafluoroethyl)trifluorophosphate ([FAP]?) for anions. For CHF2CH3, [N(nC4H9)4][BF4] and [N(nC4H9)4][B{3,5-C6H3(CF3)2}4] have been investigated for comparison with the previously measured solubility and conductivity in CH2F2. We have found that [N(nC4H9)4][Al(OC(CF3)3)4], [N(nC4H9)4][FAP] and [N(CH3)4][FAP] have much higher molar conductivity in scCH2F2 at similar conditions than [N(nC4H9)4][BF4], a widely used commercial electrolyte. Additionally, scCHF2CH3 shows potential for use as the solvent for supercritical fluid electrodeposition, especially at high temperatures since high density of this fluid can be achieved at lower operating pressures than similar fluids that can be used to produce electrochemical baths with comparable conductivity.

Full text not available from this repository.

More information

Accepted/In Press date: 26 April 2016
e-pub ahead of print date: 11 May 2016
Organisations: Chemistry

Identifiers

Local EPrints ID: 398641
URI: http://eprints.soton.ac.uk/id/eprint/398641
ISSN: 1463-9076
PURE UUID: f2db53d4-1e3a-45e9-810d-42c53b961e72
ORCID for William Levason: ORCID iD orcid.org/0000-0003-3540-0971
ORCID for Gillian Reid: ORCID iD orcid.org/0000-0001-5349-3468

Catalogue record

Date deposited: 29 Jul 2016 12:49
Last modified: 15 Sep 2021 01:37

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×