A non-cationic crosslinking strategy to improve the performance of anion exchange membranes based on poly(aryl piperidinium) for fuel cells

Abstract

As a backbone with ether-free for anion exchange membranes (AEMs) with good alkali stability, poly(aryl-co-aryl piperidine) (c-PAP) has received much attention in the development of polyelectrolytes. More importantly, the trade-off between high conductivity and stability has been a thorny issue for researchers in the study of AEMs. Typically, non-cationic crosslinked membranes have lower water absorption and swelling rates compared to multi-cationic crosslinked membranes, resulting in better dimensional stability of the membrane. Here, we designed a non-cationic crosslinked AEMs based on poly(p-terphenyl-co-1,2-diphenylethane piperidinium) (PDTP). The experimental results show that the combination of hydrophobic crosslinking and side chain induction results in excellent conductivity and alkali resistance of the membranes. The crosslinked membranes reached an OH- conductivity of 104.61 mS cm−1 and a swelling rate of less than 15 % at 80 °C. In addition, the length of the hydrophobic crosslinker was varied to explore its effect on the membrane properties. The PDTP-BMP-6 C membrane (C=6 in crosslinker) shows the most excellent overall performance among them. The conductivity was retained at 86.5 % after immersion in 2 M NaOH at 80 °C for 720 h, and the peak power density reached 214 mW cm−2.