Polyaromatic anion exchange membranes for alkaline fuel cells with high hydroxide conductivity and alkaline stability

Abstract

Poly (terphenylene-methyl piperidine-biphenyl) was synthesized using biphenyl, terphenyl, and N-methyl-4-piperidone as raw materials to prepare anion exchange membranes (AEMs). Biphenyl and terphenyl as the copolymer monomers were used to regulate the morphology and properties of the AEMs. The flexible copolymer backbone promoted efficient transport of hydroxyl ions. The obtained AEMs show a high ion conductivity of 49.16 mS/cm at 80 C. Furthermore, the stable piperidine cation and polyarylene chain contributed to the excellent alkaline stability of AEMs that showed only 0.63% deterioration in ion conductivity after soaking in 1 M KOH at 80 C for 720 h. The peak of single cell power density of 54 mW cm À2 was obtained at a load current density of 150.1 mA cm À2 using an aqueous solution containing 1 M methanol and 1 M potassium hydroxide as the anode fuel, and pure oxygen gases as the cathode fuel at 30 C.

A novel anion exchange membrane comprised of three aromatic units for fuel cells

“…This may be due to the fact that with the addition of the biphenyl unit, the spatial structure of the membrane changes resulting in a decrease in water absorption, which in turn causes a decrease in ionic conductivity. 25,33…”

“…This may be due to the fact that with the addition of the biphenyl unit, the spatial structure of the membrane changes resulting in a decrease in water absorption, which in turn causes a decrease in ionic conductivity. 25,33 Moreover, Figure 9 shows the Arrhenius curve of AEMs, and the OHmigration activation energy of the prepared membranes ranges from 12.26 to 16.81 kJ mol À1 . Among them, PMDBP-30 has the lowest Ea of 12.26 kJ mol À1 , indicating the least resistance to OH À transport in the membranes.…”

Comb‐shaped block poly(arylene ether sulfone ketone)s for anion exchange membranes

“…Numerous polymers have been explored as the AEMs' backbones, including poly(arylene ether ketone) (PEK), 9,10 poly(arylene ether sulfone) (PES), 11,12 poly(phenylene oxide) (PPO), 13,14 polybenzimidazole (PBI), 15,16 poly(crown ether) (PCE) 17,18 and several heteroatom‐free polymers like poly(arylene alkylene), 19–21 polyfluorenes 22 and polyalkenes 23 . In addition, various functional cationic groups, such as quaternary ammonium, 10,20–22 imidazolium, 9,11 guanidinium, 24 phosphonium, 25 pyrrolidinium, 26 piperidinium 27,28 and some metal‐based cations, 29 have been studied and utilized for AEMs.…”