Preparation, characterization and enhanced performance of functional crosslinked membranes using poly(vinyl alcohol) as macromolecular crosslinker for fuel cells

Abstract

Functional cross-linked membranes based on sulfonated poly(arylene ether ketone sulfone) containing pendant carboxyl groups (C-SPAEKS) and poly(vinyl alcohol) (PVA) as macromolecular crosslinker were fabricated. The covalent cross-linking reaction was realized by thermal treatment between carboxyl and hydroxyl groups. The cross-linked membranes exhibited favorable thermal stability, good mechanical property, positive dimensional stability and desirable single cell performance. Moreover, the cross-linked membranes show low methanol permeability coefficients ranged from 4.01 × 10⁻⁷ cm⁻² s⁻¹ to 8.71 × 10⁻⁷ cm⁻² s⁻¹ with the PVA weight ratio decreased from 50% to 10%, which were much lower than that of C-SPAEKS membrane (15.97 × 10⁻⁷ cm⁻² s⁻¹). The proton conductivities of all the cross-linked membranes were above 10⁻² S cm⁻¹ at 25 °C. Moreover, the cross-linked membranes exhibited higher relative selectivity than that of composite membranes, which indicated that this series of cross-linked membranes had potential application value and were expected to be used in fuel cells.