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Title: Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans -cyclooctene derivatives

Alkaline anion exchange membranes (AAEMs) are an important component of alkaline exchange membrane fuel cells (AEMFCs), which facilitate the efficient conversion of fuels to electricity using nonplatinum electrode catalysts. However, low hydroxide conductivity and poor long-term alkaline stability of AAEMs are the major limitations for the widespread application of AEMFCs. In this paper, we report the synthesis of highly conductive and chemically stable AAEMs from the living polymerization oftrans-cyclooctenes. Atrans-cyclooctene–fused imidazolium monomer was designed and synthesized on gram scale. Using these highly ring-strained monomers, we produced a range of block and random copolymers. Surprisingly, AAEMs made from the random copolymer exhibited much higher conductivities than their block copolymer analogs. Investigation by transmission electron microscopy showed that the block copolymers had a disordered microphase segregation which likely impeded ion conduction. A cross-linked random copolymer demonstrated a high level of hydroxide conductivity (134 mS/cm at 80 °C). More importantly, the membranes exhibited excellent chemical stability due to the incorporation of highly alkaline-stable multisubstituted imidazolium cations. No chemical degradation was detected by1H NMR spectroscopy when the polymers were treated with 2 M KOH in CD3OH at 80 °C for 30 d.

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Award ID(s):
1719875
NSF-PAR ID:
10103644
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Proceedings of the National Academy of Sciences
Date Published:
Journal Name:
Proceedings of the National Academy of Sciences
ISSN:
0027-8424
Page Range / eLocation ID:
Article No. 201900988
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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