Mechanically robust semi-interpenetrating polymer network via thiol-ene chemistry with enhanced conductivity for anion exchange membranes

Anion exchange membranes (AEMs) have emerged as crucial functional materials in various electrochemical device, such as fuel cell. Both the mechanical property and ionic conductivity play important roles in AEMs. Herein, a series of semi-interpenetrating polymer network AEMs are prepared by introducing flexible polyvinyl alcohol to the rigid photo-crosslinked poly (2,6-dimethyl-1,4-phenylene oxide) network. Such strategy endows AEM with tunable composition and mechanical property. Among these AEMs, membrane with an IEC of 1.46 mmol/g shows the highest mechanical strength of 30.8 MPa and a relatively lower swelling ratio, as well as the highest hydroxide conductivity. Importantly, the alkaline stability of these AEMs has been improved, 66.5% of the hydroxide conductivity is maintained after treatment in 1 M NaOH at 80 °C for 1000 h. Tentative assembly of H₂/O₂ fuel cell at 60 °C with this AEM displays a peak power density of 78 mW/cm². All the results demonstrate that sIPN structure is a promising way to enhance the mechanical property, ionic conductivity, and the alkaline stability of AEMs for the future application in AEMFCs.