Synthesis of poly(vinyl alcohol-co-diallyl dimethylammonium chloride) and its use in an anion exchange membrane for water electrolysis (AEMWE)

Anion exchange membrane water electrolysis (AEMWE) is a promising technology for hydrogen production from renewable energy sources. However, the limited stability of the currently used anion exchange membranes and their poor mechanical properties are factors that preclude its diffusion. Poly(N,N-diallylazacycloalkane)s are characterized by stability in alkaline environment, which makes them excellent candidates for the obtainment of AEM for water electrolysis. Herein, a copolymer of diallyldimethylammonium chloride and vinyl acetate was synthesized, hydrolysed to free the alcohol group, and subsequently crosslinked with glutaraldehyde. This material was then supported on a polypropylene microporous film to obtain a composite AEM able to combine excellent mechanical properties (124.7 MPa tensile strength) with a low Area Specific Resistance (0.198 Ω cm2 at 60 °C) and an ion exchange capacity of 1.2 mmol g−1. The electrochemical performances of the membranes were evaluated by through-plane conductivity measurement and tests in a pilot-scale AEM electrolyzer (50 cm2 active area). Stability was checked by measuring the IEC values and weight loss after an aging test of 960 h in 1 M KOH solution at 80 °C; furthermore, a continuous electrolyzer cell test was performed for 125 h.