An effective strategy for the preparation of a wide-temperature-range proton exchange membrane based on polybenzimidazoles and polyacrylamide hydrogels

Abstract

Proton-exchange membrane fuel cells (PEMFCs) with high performances over a wide temperature range from 80–180 °C have gained much attention related to the development of fuel cell vehicles. Designing membranes operating within a wide temperature range, especially covering the low temperature and high temperature ranges, is highly meaningful because of their potential for practical application. Phosphoric acid (PA)-doped polybenzimidazoles (PBIs) show great potential for use as high-temperature proton exchange membranes. However, a poor fuel cell performance at low temperatures (<100 °C) limits their application. In this work, different contents of three-dimensional network polyacrylamide hydrogels were introduced into OPBI (OPBI-AM) membranes via a unique design to simultaneously absorb phosphoric acid and water. Due to their strong phosphoric acid and water absorption abilities, the OPBI-AM membranes were highly conductive over a wide temperature range (40–180 °C) compared to the original OPBI membrane. The single-cell performance of OPBI-0.8AM achieved maximum power densities of 200 and 565 mW cm⁻² at 80 °C and 160 °C, respectively, under anhydrous conditions. Besides, the low temperature cell cycles of OPBI-0.8AM membrane exhibited stability in a week. The performance of this new PEM extends beyond the limits of existing HT-PEMFCs materials via innovative design compared to the current OPBI-based PEMFC systems.