Highly conductive and robustly stable anion exchange membranes with a star-branched crosslinking structure

In order to improve the ionic conductivity and durability of anion exchange membranes (AEMs), novel ether free AEMs are prepared based on 6-bromo-1-hexanol quaternized poly(terphenyl piperidine)s by construction of a star-branched crosslinking structure via a crosslinker of 1,3,5-tris(bromomethyl)benzene. The star-branched crosslinking network enhances the dimensional stability and mechanical property without occupying the active sites for cation production. Suitable microphase separations with ionic cluster spacing within 19.68-20.72 nm are formed according to the SAXS results. The proposed AEMs exhibit hydroxide ion (OH?) conductivity ranging from 118 to 136 mS cm-1 at 80 & DEG;C. The dense crosslinking structure and flexible side chains endow the AEMs with excellent resistance against the attack of OH? ions. About 80% of the conductivity retention rate is achieved after immersing the AEMs in 1 mol L-1 KOH aqueous solutions at 80 & DEG;C for 1600 h. A single H2/O2 fuel cell employing the prepared membrane as the electrolyte exhibits a peak power density of 639 mW cm-2 at 60 & DEG;C without back pressure.

Automated summary

Novel ether free anion exchange membranes (AEMs) with a star-branched crosslinking structure were prepared, which demonstrated improved ionic conductivity and durability. Suitable microphase separations were formed with ionic cluster spacing within 19.68-20.72 nm according to SAXS results. The AEMs exhibited hydroxide ion conductivity ranging from 118 to 136 mS cm-1 at 80°C and showed excellent resistance against the attack of OH- ions.