Blend membranes of polybenzimidazole and an anion exchange ionomer (FAA3) for alkaline water electrolysis: Improved alkaline stability and conductivity

Authors
Konovalova, AnastasiiaKim, HyemiKim, SangwonLim, AhyounPark, Hyun SeoKraglund, Mikkel RykaerAili, DavidJang, Jong HyunKim, Hyoung-JuhnHenkensmeier, Dirk
Issue Date
2018-10
Publisher
ELSEVIER SCIENCE BV
Citation
JOURNAL OF MEMBRANE SCIENCE, v.564, pp.653 - 662
Abstract
Anion exchange membranes (AEMs) conduct selectively hydroxide ions, while KOH doped polybenzimidazole is an ion-solvating polymer, conducting both potassium and hydroxide ions. In this work, meta-polybenzimidazole (mPBI) was blended with FAA3, a commercially available AEM, in the ratios of 2: 1, 3: 1, 4: 1, 5: 1 and 1: 0. Doping was done by immersion in 0, 10, 15, 20, 25 and 30 wt% KOH solutions, giving rise to 30 membranes which were analyzed for their swelling behavior during doping, there composition (polymer, water, KOH), their mechanical properties and their through-plane conductivity in KOH solutions. Especially PF-41 showed higher tensile strength and Young's modulus than mPBI under all tested KOH concentrations. The highest conductivity of 166 mS cm(-1) was observed for PF-51 doped in 25% KOH, 80% higher than for mPBI. In an alkaline stability test, blend membranes showed higher tensile strength, Young's modulus and lower weight loss than mPBI after 4 weeks at 85 degrees C in 25 wt% KOH solution. PF-31 and PF-41 were also tested in an electrolysis cell, where they showed cell resistance comparable to mPBI. Because systems without cathode feed can be quite efficient, the permeability of membranes for KOH solutions was investigated.
Keywords
SOLVATING POLYMER ELECTROLYTE; KOH-DOPED POLYBENZIMIDAZOLE; FUEL-CELLS; POTASSIUM HYDROXIDE; PERFORMANCE; PBI; Polybenzimidazole; Anion exchange membranes; Blend polymers; Alkaline electrolysis; Alkaline stability
ISSN
0376-7388
URI
https://pubs.kist.re.kr/handle/201004/120829
DOI
10.1016/j.memsci.2018.07.074
Appears in Collections:
KIST Article > 2018
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