Poly(Vinyl Alcohol-Co-Vinyl Acetal) Gel Electrolytes for Alkaline Water Electrolysis

30 Pages Posted: 6 Mar 2023

See all articles by David Aili

David Aili

Technical University of Denmark

Yifan Xia

Technical University of Denmark

Sinu C. Rajappan

Technical University of Denmark

Dmytro Serhiichuk

Technical University of Denmark

Mikkel Rykær Kraglund

Technical University of Denmark

Jens Oluf Jensen

Technical University of Denmark

Abstract

A series of poly(vinyl alcohol-co-vinyl acetal) gel electrolytes was synthesized, characterized and assessed as electrode separators in alkaline water electrolysis. The copolymers were prepared by reacting poly(vinyl alcohol) with benzaldehyde or 4-formylbenzoic acid under acidic conditions at different ratios, and visually homogenous and water-insoluble membranes were subsequently obtained by solution casting. The physicochemical characteristics in terms of electrolyte uptake, swelling behavior, and ion conductivity could be tuned by varying the degree of functionalization. At a moderate vinyl acetal content of 5%, the membrane combined mechanical robustness with ion conductivity reaching 36 mS cm-1 in 30 wt.% aqueous KOH at room temperature. Current densities of up to 1000 mA cm-2 were reached with uncatalyzed Ni-foam electrodes at a cell voltage of less than 2.6 V in alkaline water electrolysis tests, while the membrane effectively prevented hydrogen crossover. Although apparent membrane degradation was observed after a few days of electrolysis operation, the strategies presented in this work to tune membrane properties are of general relevance to the field towards the development of new ion-solvating membrane systems based on more alkaline stable and robust backbone chemistries.

Keywords: Poly(vinyl alcohol), polymer electrolyte membrane, Ion-solvating membrane, Alkaline electrolysis, conductivity

Suggested Citation

Aili, David and Xia, Yifan and Rajappan, Sinu C. and Serhiichuk, Dmytro and Kraglund, Mikkel Rykær and Oluf Jensen, Jens, Poly(Vinyl Alcohol-Co-Vinyl Acetal) Gel Electrolytes for Alkaline Water Electrolysis. Available at SSRN: https://ssrn.com/abstract=4380075 or http://dx.doi.org/10.2139/ssrn.4380075

David Aili (Contact Author)

Technical University of Denmark ( email )

Anker Engelunds Vej 1
Building 101A
Lyngby, 2800
Denmark

Yifan Xia

Technical University of Denmark ( email )

Anker Engelunds Vej 1
Building 101A
Lyngby, 2800
Denmark

Sinu C. Rajappan

Technical University of Denmark ( email )

Anker Engelunds Vej 1
Building 101A
Lyngby, 2800
Denmark

Dmytro Serhiichuk

Technical University of Denmark ( email )

Anker Engelunds Vej 1
Building 101A
Lyngby, 2800
Denmark

Mikkel Rykær Kraglund

Technical University of Denmark ( email )

Anker Engelunds Vej 1
Building 101A
Lyngby, 2800
Denmark

Jens Oluf Jensen

Technical University of Denmark ( email )

Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Downloads
48
Abstract Views
233
PlumX Metrics