A polytetrafluoroethylene-quaternary 1,4-diazabicyclo-[2.2.2]-octane polysulfone composite membrane for alkaline anion exchange membrane fuel cells

The quaternary 1,4-diazabicyclo-[2.2.2]-octane (DABCO) polysulfone (QDPSU) was synthesised. A thin (30 μm) composite membrane based on polytetrafluoroethylene (PTFE) and QDPSU was obtained by impregnation method of QDPSU solution in PTFE support. SEM images revealed a dense and homogenous structure of PTFE-QDPSU membrane. The PTFE-QDPSU composite membrane showed good mechanical strength (a 32 MPa maximum load), and a water uptake of 61 ± 3% and a 17 ± 2% swelling degree. An ionic conductivity of 0.051 S cm−1 was achieved at 50 °C and 100% RH. Preliminary data of a single MEA gave power outputs of 146 and 103 mW cm−2 with oxygen and air respectively.

► A thin PTFE-QDPSU composite membrane was prepared for alkaline anion exchange membrane fuel cells to overcome the low mobility of hydroxide ion compared to proton.
► PTFE support was used to improve the physical properties (e.g. mechanical strength, swelling degree and water uptake).
► The ionic conductivity of PTFE-QDPSU composite membrane was up to 0.051 S cm−1 and the highest powder output was 146 mW cm−2 using hydrogen and pure oxygen.