Construction of alkali-stable anion exchange membranes with hydrophilic/hydrophobic microphase separation structure by adjusting side chain length

Abstract

A series of side-chains anion exchange membranes were assembled by poly (arylene ether ketone) with amino groups (Am-PAEK) which was grafted different length of side chains by Friedel-Crafts acylation and then imidazole cationic groups were introduced by bromination reaction. The side-chain membranes exhibited excellent mechanical properties, thermal stability and alkali stability. In addition, swelling ratios of side chain membranes were lower than 10% even at 100 °C. And the alkali stability of Im-AP-6 (where Am-PAEK was grafted with 6-bromohexanoyl chloride and then grafted with 1,2-dimethylimidazole.) was higher than 87% after immersing in 1 M NaOH for 168 h at 60 °C. Hydroxide conductivities of the membranes were in the range of 43.5 ∼ 49.8 mS cm−1 at 30 °C and 87.3 ∼ 126.6 mS cm−1 at 80 °C. The open circuit voltage (OCV) and peak power density of Im-AP-6 were 1.13 V and 389.71 mW cm−2 (80 °C, 100% RH), respectively. The results showed side-chain membranes have good comprehensive properties and substantially possible as AEMs.