Optimization of the pendant chain length in partially fluorinated aromatic anion exchange membranes for alkaline fuel cells

For robust anion exchange membranes, we have investigated the effect of aliphatic side chains on the properties of partially fluorinated aromatic copolymers (QPAFs) with ammonium groups. A new series of QPAF membranes with various interstitial aliphatic side chain lengths (QPAF-C x ) where x = 2–6 w...

Full description

Saved in:
Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2018, Vol.6 (29), p.14400-14409
Main Authors: Ahmed Mahmoud, Ahmed Mohamed, Miyatake, Kenji
Format: Article
Language:English
Subjects:
Aliphatic compounds
Ammonium
Anion exchange
Anion exchanging
Chains
Chemical synthesis
Conductivity
Durability
Fluorination
Fuel cells
Fuel technology
Ion exchange
Ions
Mechanical properties
Membranes
Morphology
Optimization
Propylene
Stability
Water uptake
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:For robust anion exchange membranes, we have investigated the effect of aliphatic side chains on the properties of partially fluorinated aromatic copolymers (QPAFs) with ammonium groups. A new series of QPAF membranes with various interstitial aliphatic side chain lengths (QPAF-C x ) where x = 2–6 were successfully synthesized. QPAF-C3 with a propylene side chain and ion exchange capacity (IEC = 1.24 meq. g −1 ) showed balanced properties with the highest hydroxide ion conductivity (99 mS cm −1 at 80 °C in water) and relatively low water uptake, based on a well-developed phase separated morphology. Moreover, the QPAF-C3 membrane exhibited excellent alkaline stability to maintain high ion conductivity (98% remaining) and high mechanical properties after 1000 h in 1 M KOH at 80 °C. The QPAF-C3 membrane also revealed reasonable stability even in 4 M and 8 M KOH at 80 °C. In fuel cell operation, the QPAF-C3 membrane exhibited a higher power density (224 mW cm −2 ) than those of our previous QPAF-C1 (138 mW cm −2 ), QPAF-C1B (167 mW cm −2 ), and Tokuyama A-201 (122 mW cm −2 ) membranes. In the durability test for 62 h, QPAF-C3 maintained 69% of its initial voltage with minor structural degradation.
ISSN:2050-7488
2050-7496
DOI:10.1039/C8TA04310H