Metallo-Polyelectrolyte-Based Robust Anion Exchange Membranes via Acetalation of a Commodity Polymer

Metallo-polyelectrolytes have been demonstrated to be promising candidates for anion exchange membranes (AEMs) due to their excellent alkaline stability. Here, cobaltocenium-containing metallo-polyelectrolyte-based AEMs with good chemical stability and dimensional stability were prepared through facile acetalation of a commodity polymer, poly(vinyl alcohol). The AEM crosslinked with 1 wt % glutaraldehyde (GA) exhibits a comparable hydroxide conductivity of 72 mS/cm at 80 °C and enhanced alkaline stability in 1 M NaOH at 80 °C (maintained 86.3% of initial hydroxide conductivity after 1000 h). The dimensional stability of these AEMs can be tuned through acetalation crosslinking with GA, and the swelling ratio of 1% GA was 17.8% and the gel fraction was 90.5%. The H2/O2 single cell using 1% GA AEM (50 μm, Fumion ionomer) showed a maximum power density of 120 mW/cm2 at 60 °C without backpressure. This work provides a facile method for the preparation of stable metallo-polyelectrolyte-based alkaline membrane fuel cells.