Novel piperidinium-functionalized crosslinked anion exchange membrane with flexible spacers for water electrolysis

Anion Exchange membranes (AEM) are core components for alkaline electrochemical energy technology, such as the AEM water electrolysis and AEM fuel cell. They are regarded as promising alternatives for proton exchange membrane-based systems due to the possibility of using noble metal-free electrocatalyst. However, chemical stability and conductivity of the membrane are still the main challenge of the electrolyzer system. Here in we highlight an AEM with styrene-b-ethylene-b-butylene-b-styrene copolymer (SEBS) as its backbone and piperidinium functioned flexible ethylene oxide spacer structure as its side-chains (SEBS-P2O6). This membrane reached 20.8 mS cm−1 hydroxide ion conductivity at room temperature, which is higher compared to previously obtained piperidinium functionalized SEBS with 10.09 mS cm−1[1]. The SEBS-P206 was measured in a single cell AEM electrolysis cell with platinum group metal (PGM) catalyst. Current densities 275 mA cm−2 and 680 mA cm−2 at 60 °C and 2 V cell potential were achieved in ultra-pure ware (UPW) and 0.1 M KOH, respectively. Remarkably, in UPW the degradation rate was only 140 μA h−1 cm−2, which is the lowest reported up to know. Single cell in ultra-pure water the degradation rate was only 140 μA h−1 cm−2, which is the lowest reported up to know. [Display omitted] •The flexible ethylene oxide spacer structure can largely improve the conductivity.•Current densities 275 mA cm−2 and 680 mA cm−2 were achieved in ultra-pure ware (UPW) and 0.1 M KOH, respectively.•In UPW at 60 °C the degradation rate was only 140 μA h−1 cm−2, which is the lowest reported up to know.