Functionalized graphene oxide cross-linked poly(2,6-dimethyl-1,4-phenylene oxide)-based anion exchange membranes with superior ionic conductivity

Composite anion exchange membranes (AEMs) with superior conductivity are developed by cross-linking of ammonium quaternized poly(2,6-dimethyl-1,4-phenylene oxide) (QPPO) with tertiary amine groups functionalized GO (NGO). Compared to the pristine QPPO membrane, the fabricated composite anion exchange membranes (QPPO-NGOx, x refers to the NGO mass percentage in the membrane) exhibit less water uptake and swelling ratio but higher ion conductivity and alkaline stability. A hydroxide conductivity as high as 123 mS cm−1 is reached by the proposed composite membrane at 80 °C. The conductivity of about 83 mS cm−1 is retained after the composite membrane immersed in 2 mol L−1 KOH aqueous solutions at 60 °C for 384 h. While the QPPO membrane turns into fragile after soaked in alkaline solutions for only 144 h. The single fuel cell based on the QPPO and QPPO-NGO2 membranes demonstrates a peak power density of 289.3 mW cm−2 at 0.53 V and 397.8 mW cm−2 at 0.61 V, respectively, at 60 °C feeding with humidified hydrogen and oxygen under a back pressure of 0.1 MPa.