Facile construction of a highly proton-conductive matrix-mixed membrane based on a –SO3H functionalized polyamide?

Soft Matter Pub Date: 2022-07-12 DOI: 10.1039/D2SM00451H

Abstract

Developing a facile strategy to construct low-cost and efficient proton-conductive electrolytes is pivotal in the practical application of proton exchange membrane (PEM) fuel cells. Herein, a polyamide with in-built –SO3H moieties, PA(PhSO3H)2, was synthesized via a simple one-pot polymeric acylation process. Investigations via electrochemical impedance spectroscopy (EIS) measurements revealed that the fabricated PA(PhSO3H)2 displays a proton conductivity of up to 5.54 × 10?2 S cm?1 at 353 K under 98% relative humidity (RH), which is more than 2 orders of magnitude higher than that of its –SO3H-free analogue PA(Ph)2 (2.38 × 10?4 S cm?1) under the same conditions. Therefore, after mixing with polyacrylonitrile (PAN) at different ratios, PA(PhSO3H)2-based matrix-mixed membranes were subsequently made and the analysis results revealed that the proton conductivity can reach up to 5.82 × 10?2 S cm?1 at 353 K and 98% RH when the weight ratio of PA(PhSO3H)2?:?PAN is in 3?:?1 (labeled as PA(PhSO3H)2–PAN(3?:?1)), the value of which is comparable even to those of commercially available electrolytes that are used in PEM fuel cells. In addition, continuous testing shows that PA(PhSO3H)2–PAN(3?:?1) possesses long-life reusability. This work demonstrates that, utilizing the simple reaction of polymeric acylation with a sulfonated module as a precursor, highly effective proton-conductive membranes for PEM fuel cells can be achieved in a facile manner.

Graphical abstract: Facile construction of a highly proton-conductive matrix-mixed membrane based on a –SO3H functionalized polyamide
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