Spirobiindane-Based Poly(arylene ether sulfone) Ionomers for Alkaline Anion Exchange Membrane Fuel Cells

In this study, spirobiindane-based poly(arylene ether sulfone)s with quaternary ammonium-functionalized side chains were synthesized as alkaline anion exchange membrane fuel cell (AEMFC) electrode binding materials. A series of novel AEMFC electrode ionomers with different main-chain structures were prepared. Three-dimensional spirobiindane structures were introduced to improve the gas permeability of the binding material. The ionomers were characterized by NMR and thermogravimetric analysis. Single-cell performance tests using the ionomers were also carried out. The ionomer sample with a spirobiindane unit in the polymer backbone and quaternary ammonium-functionalized hexyloxy side chain showed good potential for AEMFC applications. A single-cell using this ionomer as a binder exhibited a peak power density of 140 mW/cm2. The modification of main-chain is considered to be a suitable approach for the synthesis of AEMFC electrode ionomers.