Durable and highly proton conducting poly(arylene perfluorophenylphosphonic acid) membranes
Kang, Na Rae ; Pham, Thanh Huong LU ; Nederstedt, Hannes LU and Jannasch, Patric LU
(2021)
In Journal of Membrane Science
623.
- Abstract
- Phosphonated aromatic polymers show several important advantages as proton exchange membranes (PEMs), including high thermal and chemical stability. However, the conductivity needs to be significantly enhanced for most electrochemical applications. Here, we have prepared a series poly(p-terphenyl perfluoroalkylene)s functionalized with highly acidic perfluorophenylphosphonic acid by first carrying out triflic acid mediated polyhydroxylations of p-terphenyl, 2,2,2-trifluoroacetophenone and perfluoroacetophenone. Subsequently, the resulting polymers were quantitatively and selectively phosphonated in the para positions of the pendant perfluorophenyl units by employing an efficient Michaelis-Arbuzov reaction. X-ray... (More)
- Phosphonated aromatic polymers show several important advantages as proton exchange membranes (PEMs), including high thermal and chemical stability. However, the conductivity needs to be significantly enhanced for most electrochemical applications. Here, we have prepared a series poly(p-terphenyl perfluoroalkylene)s functionalized with highly acidic perfluorophenylphosphonic acid by first carrying out triflic acid mediated polyhydroxylations of p-terphenyl, 2,2,2-trifluoroacetophenone and perfluoroacetophenone. Subsequently, the resulting polymers were quantitatively and selectively phosphonated in the para positions of the pendant perfluorophenyl units by employing an efficient Michaelis-Arbuzov reaction. X-ray scattering of proton exchange membranes (PEMs) based on the phosphonated polymers showed efficient ionic clustering with the interdomain distance depending on the acid content of the polymer. Although the water uptake and swelling was moderate (even at high temperature) the PEMs showed high proton conductivity, up to 111 mS cm-1 at 80 °C fully hydrated, and reaching 4 mS cm-1 at 50% RH at the same temperature. This may be ascribed to the distinct phase separation and high acidity of the polymers. The stability of the PEMs was excellent with thermal decomposition only above ~400 °C. Moreover, no change in weight, appearance or molecular structure was detected after 5 h immersion in Fenton’s reagent at 80 °C, demonstrating an excellent chemical resistance of the PEMs towards free-radical attack. The radical resistance of the present phosphonated PEMs was found to increase with the acid content, which is contrast to corresponding sulfonated PEMs. The combination of high thermochemical stability and high conductivity implies that the present materials are attractive for use as ionomers in catalyst layers and as PEMs in fuel cells and water electrolyzer applications. (Less)
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https://lup.lub.lu.se/record/e1581fff-9665-4dd0-9b90-fbab7bae0eea
- author
- Kang, Na Rae
; Pham, Thanh Huong
LU
; Nederstedt, Hannes
LU
and Jannasch, Patric
LU
- organization
- publishing date
- 2021
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Proton exchange membranes, Fuel cells, Phosphonic acid, Proton conductivity, Stability against radicals, Polyhydroxyalkylation
- in
- Journal of Membrane Science
- volume
- 623
- article number
- 119074
- pages
- 8 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:85099822497
- ISSN
- 0376-7388
- DOI
- 10.1016/j.memsci.2021.119074
- project
- Microphase Separated Cation Conducting Polymers: Design, Synthesis, and Properties
- language
- English
- LU publication?
- yes
- additional info
- Editor’s Choice Article for January, 2021
- id
- e1581fff-9665-4dd0-9b90-fbab7bae0eea
- date added to LUP
- 2020-11-29 20:11:46
- date last changed
- 2022-04-26 22:10:32
@article{e1581fff-9665-4dd0-9b90-fbab7bae0eea,
abstract = {{Phosphonated aromatic polymers show several important advantages as proton exchange membranes (PEMs), including high thermal and chemical stability. However, the conductivity needs to be significantly enhanced for most electrochemical applications. Here, we have prepared a series poly(<i>p</i>-terphenyl perfluoroalkylene)s functionalized with highly acidic perfluorophenylphosphonic acid by first carrying out triflic acid mediated polyhydroxylations of <i>p</i>-terphenyl, 2,2,2-trifluoroacetophenone and perfluoroacetophenone. Subsequently, the resulting polymers were quantitatively and selectively phosphonated in the <i>para</i> positions of the pendant perfluorophenyl units by employing an efficient Michaelis-Arbuzov reaction. X-ray scattering of proton exchange membranes (PEMs) based on the phosphonated polymers showed efficient ionic clustering with the interdomain distance depending on the acid content of the polymer. Although the water uptake and swelling was moderate (even at high temperature) the PEMs showed high proton conductivity, up to 111 mS cm<sup>-1</sup> at 80 °C fully hydrated, and reaching 4 mS cm<sup>-1</sup> at 50% RH at the same temperature. This may be ascribed to the distinct phase separation and high acidity of the polymers. The stability of the PEMs was excellent with thermal decomposition only above ~400 °C. Moreover, no change in weight, appearance or molecular structure was detected after 5 h immersion in Fenton’s reagent at 80 °C, demonstrating an excellent chemical resistance of the PEMs towards free-radical attack. The radical resistance of the present phosphonated PEMs was found to increase with the acid content, which is contrast to corresponding sulfonated PEMs. The combination of high thermochemical stability and high conductivity implies that the present materials are attractive for use as ionomers in catalyst layers and as PEMs in fuel cells and water electrolyzer applications.}},
author = {{Kang, Na Rae and Pham, Thanh Huong and Nederstedt, Hannes and Jannasch, Patric}},
issn = {{0376-7388}},
keywords = {{Proton exchange membranes; Fuel cells; Phosphonic acid; Proton conductivity; Stability against radicals; Polyhydroxyalkylation}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Journal of Membrane Science}},
title = {{Durable and highly proton conducting poly(arylene perfluorophenylphosphonic acid) membranes}},
url = {{http://dx.doi.org/10.1016/j.memsci.2021.119074}},
doi = {{10.1016/j.memsci.2021.119074}},
volume = {{623}},
year = {{2021}},
}