Zero-Gap Alkaline Water Electrolysis Using Ion-Solvating Polymer Electrolyte Membranes at Reduced KOH Concentrations

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Abstract

Membranes based on poly(2,2'-(m-phenylene)-5,5-bibenzimidazole) (m-PBI) can dissolve large amounts of aqueous KOH to give electrolyte systems with ion conductivity in a practically useful range. The conductivity of the membrane strongly depends on the concentration of the aqueous KOH phase, reaching about 10-1 S cm-1 or higher in 15-25 wt% KOH. Herein, m-PBI membranes are systematically characterized with respect to performance and short-term stability as electrolyte in a zero-gap alkaline water electrolyzer at different KOH concentrations. Using plain uncatalyzed nickel foam electrodes, the cell based on m-PBI outperforms the cell based on the commercially available state-of-the-art diaphragm and reaches a current density of 1500 mA cm-2 at 2.4 V in 20 wt% KOH at 80°C. The cell performance remained stable during two days of operation, though post analysis of the membrane using size exclusion chromatography and spectroscopy reveal evidence of oxidative degradation of the base polymer at KOH concentrations of 15 wt% and higher.
Original languageEnglish
JournalJournal of The Electrochemical Society
Volume163
Issue number11
Pages (from-to)F3125-F3131
Number of pages7
ISSN0013-4651
DOIs
Publication statusPublished - 2016

Bibliographical note

This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.

Keywords

  • Alkaline
  • Membrane
  • Polybenzimidazole
  • Water electrolysis
  • Zero-gap

Cite this

@article{08bca45067184df0a05be3d2895f8138,
title = "Zero-Gap Alkaline Water Electrolysis Using Ion-Solvating Polymer Electrolyte Membranes at Reduced KOH Concentrations",
abstract = "Membranes based on poly(2,2'-(m-phenylene)-5,5-bibenzimidazole) (m-PBI) can dissolve large amounts of aqueous KOH to give electrolyte systems with ion conductivity in a practically useful range. The conductivity of the membrane strongly depends on the concentration of the aqueous KOH phase, reaching about 10-1 S cm-1 or higher in 15-25 wt{\%} KOH. Herein, m-PBI membranes are systematically characterized with respect to performance and short-term stability as electrolyte in a zero-gap alkaline water electrolyzer at different KOH concentrations. Using plain uncatalyzed nickel foam electrodes, the cell based on m-PBI outperforms the cell based on the commercially available state-of-the-art diaphragm and reaches a current density of 1500 mA cm-2 at 2.4 V in 20 wt{\%} KOH at 80°C. The cell performance remained stable during two days of operation, though post analysis of the membrane using size exclusion chromatography and spectroscopy reveal evidence of oxidative degradation of the base polymer at KOH concentrations of 15 wt{\%} and higher.",
keywords = "Alkaline, Membrane, Polybenzimidazole, Water electrolysis, Zero-gap",
author = "Kraglund, {Mikkel Ryk{\ae}r} and David Aili and {Jankova Atanasova}, Katja and Erik Christensen and Qingfeng Li and Jensen, {Jens Oluf}",
note = "This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.",
year = "2016",
doi = "10.1149/2.0161611jes",
language = "English",
volume = "163",
pages = "F3125--F3131",
journal = "Journal of The Electrochemical Society",
issn = "0013-4651",
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TY - JOUR

T1 - Zero-Gap Alkaline Water Electrolysis Using Ion-Solvating Polymer Electrolyte Membranes at Reduced KOH Concentrations

AU - Kraglund, Mikkel Rykær

AU - Aili, David

AU - Jankova Atanasova, Katja

AU - Christensen, Erik

AU - Li, Qingfeng

AU - Jensen, Jens Oluf

N1 - This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.

PY - 2016

Y1 - 2016

N2 - Membranes based on poly(2,2'-(m-phenylene)-5,5-bibenzimidazole) (m-PBI) can dissolve large amounts of aqueous KOH to give electrolyte systems with ion conductivity in a practically useful range. The conductivity of the membrane strongly depends on the concentration of the aqueous KOH phase, reaching about 10-1 S cm-1 or higher in 15-25 wt% KOH. Herein, m-PBI membranes are systematically characterized with respect to performance and short-term stability as electrolyte in a zero-gap alkaline water electrolyzer at different KOH concentrations. Using plain uncatalyzed nickel foam electrodes, the cell based on m-PBI outperforms the cell based on the commercially available state-of-the-art diaphragm and reaches a current density of 1500 mA cm-2 at 2.4 V in 20 wt% KOH at 80°C. The cell performance remained stable during two days of operation, though post analysis of the membrane using size exclusion chromatography and spectroscopy reveal evidence of oxidative degradation of the base polymer at KOH concentrations of 15 wt% and higher.

AB - Membranes based on poly(2,2'-(m-phenylene)-5,5-bibenzimidazole) (m-PBI) can dissolve large amounts of aqueous KOH to give electrolyte systems with ion conductivity in a practically useful range. The conductivity of the membrane strongly depends on the concentration of the aqueous KOH phase, reaching about 10-1 S cm-1 or higher in 15-25 wt% KOH. Herein, m-PBI membranes are systematically characterized with respect to performance and short-term stability as electrolyte in a zero-gap alkaline water electrolyzer at different KOH concentrations. Using plain uncatalyzed nickel foam electrodes, the cell based on m-PBI outperforms the cell based on the commercially available state-of-the-art diaphragm and reaches a current density of 1500 mA cm-2 at 2.4 V in 20 wt% KOH at 80°C. The cell performance remained stable during two days of operation, though post analysis of the membrane using size exclusion chromatography and spectroscopy reveal evidence of oxidative degradation of the base polymer at KOH concentrations of 15 wt% and higher.

KW - Alkaline

KW - Membrane

KW - Polybenzimidazole

KW - Water electrolysis

KW - Zero-gap

U2 - 10.1149/2.0161611jes

DO - 10.1149/2.0161611jes

M3 - Journal article

VL - 163

SP - F3125-F3131

JO - Journal of The Electrochemical Society

JF - Journal of The Electrochemical Society

SN - 0013-4651

IS - 11

ER -