A mechanically robust multication double-network polymer as an anion-exchange membrane: High ion conductivity and excellent chemical stability

Abstract

Three membranes containing different cations with various levels of basicity were prepared for anion exchange application. All membranes show high anion conductivity at 80 °C (in the range of 83–117 mS cm−1). Beside OH− conductivity, the chemical stability and mechanical properties of membranes were tuned by changing the degree of crosslinking. As the best-optimized membrane, the Q-Poly 3 exhibit an OH− conductivity equal to 103 mS cm−1, max power density equal to 89 mW cm−2 and fuel crossover less than 10% of Nafion. Crosslinking in Q-Poly 3 cause superior mechanical properties (tensile strain equal to 40.39% and tensile strength equal to 51.25 MPa). This membrane also shows good mechanical properties after long time performance. The porous morphology of this membrane leads to the water uptake value of 91% (at room temperature), but it exhibits a relatively low swelling ratio (18%) due to the presence of crosslinking. After 14 days, Q-Poly 3 display very good chemical alkaline stability, and its anion conductivity reduce less than 7%.