Highly alkaline stability poly(aryl ether piperidinium) anion exchange membranes with partial aryl ether segments

Poly(aryl piperidinium) is considered a promising material for the preparation of anion exchange membranes (AEM) with considerable conductivity and excellent chemical stability for anion exchange membrane fuel cells (AEMFC). In this research, we report a range of biphenyl ether-containing poly(aryl ether piperidinium) unlike previous ones to increase the conductivity of AEMs and the peak power density (PPD) of fuel cells, and the alkaline stability of ether bonds in the polymer backbone is demonstrated. All of the poly(aryl ether piper-idinium) membranes possess comparable mechanical properties and inherent viscosity derived from the high activity of biphenyl ethers in superacid-catalyzed reactions, which means that large-width AEMs can be pre-pared. The data demonstrated that the poly (ether p-terphenyl piperidinium) (QPEPTpi-35) exhibited a con-ductivity of 140 mS cm- 1 at 80 degrees C compared to the original poly (p-terphenyl piperidinium) (QPTPpi) membrane owning to optimized micro-phase separation structure and higher water uptake. Meanwhile, QPEPTpi-35 membrane conductivity retention is greater than 85% after immersion in 1 M KOH for 2000 h at 80 degrees C. More-over, the PPD of the QPEPTpi-35 membrane reaches 1.2 W cm-2 in H2/O2 fuel cells, which is much higher than that of the QPTPpi membrane (0.51 W cm-2). The durability of MEA prepared by the catalyst-coated substrate (CCS) method manifests over 20 h under 0.2 A cm-2 at 60 degrees C.

Automated summary

In this research, a new type of poly(aryl ether piperidinium) membrane was developed with improved conductivity, excellent alkaline stability and mechanical properties. The conductivity and peak power density of fuel cells were increased by optimizing the micro-phase separation structure and improving water uptake. The QPEPTpi-35 membrane demonstrated superior performance in various tests, including high conductivity, alkaline stability, and power density.