Poly(aryl N-methyl quinuclidinium) anion exchange membrane with both ultra-high alkaline stability and dimensional stability

Anion exchange membrane (AEM) water electrolyser provides a promising alternative to proton exchange membrane water electrolysis due to the relative cheap of AEM and no-need of expensive platinum group catalysts. However, the development of AEM water electrolyser is hampered by the low alkaline and dimensional stability of AEMs, especially in highly concentrated alkaline solution and at elevated temperatures. Recently we synthesized a poly(triphenyl N-methylquinuclidinium) AEM with excellent alkaline stability. To further improve the mechanical strength and dimensional stability of this kind of AEM, in this work, we added trifluoacetophenone to prepare a poly(triphenyl trifluoacetophenone N-methylquinuclidinium) membrane, which exhibits superior alkaline stability (no degradation of conductivity and mechanical strength for 1600 h in 10 mol L−1 NaOH at 80°C), excellent dimensional stability (swelling ratio: <7%, in pure water, 30–80°C; <2%, in 10 mol L−1 NaOH, 30–80°C), high OH− conductivity (134.5 mS cm−1 at 80°C) and high mechanical strength (tensile strength = 43.2 MPa). The assembled water electrolyser, comprising this AEM and nickel-alloy foam electrodes, exhibits outstanding current density (1780 mA cm−2) at 2.0 V with 5 mol L−1 KOH aqueous electrolyte at 80°C, and high durability when assembled with nickel foam electrodes.