Highly stable double crosslinked membrane based on poly(vinylbenzyl chloride) for anion exchange membrane fuel cell

Anion exchange membranes (AEMs) with high ionic conductivity and excellent stability are critical for long-life AEM fuel cells. In this paper, a novel double crosslinked AEM was prepared successfully based on polybenzimidazole (PBI) and poly(vinylbenzyl chloride) (PVBC) with N,N,N″,N′-tetramethyl-1,6-hexanediamine as a homogeneous quaternization reagent. As the mass ratios of PBI and PVBC increased from 1:1 to 3:1, the water uptake and swelling ratio of AEM decreased by half, while the ionic exchange capacity had a small reduction. Moreover, little change occurred in water uptake and swelling ratio under elevated temperature, as well as the ionic exchange capacity after soaking in KOH for 500 h. When the mass ratios of PBI and PVBC was 1:1, the AEM showed the minimum tensile strength of 45.8 MPa and highest conductivity of 31.5 mS cm⁻¹ at 20 °C and 68.8 mS cm⁻¹ at 80 °C. In addition, excellent alkali resistance and oxidative stability were reflected in durability studies and the maximum power density of an H₂/O₂ single fuel cell using the AEM reached 244.93 mW cm⁻² at 0.54 V.