Polymer electrolyte membranes from Cloisite 30B-based solid proton conductor and sulfonated polyether ether ketone/polyvinylidene fluoride-co-hexafluoro propylene blends for direct methanol fuel cells

Abstract

Polymer electrolyte membranes (PEMs) were developed for direct methanol fuel cell (DMFC) applications, based on sulfonated polyether ether ketone (SPEEK) and polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) filled with Cloisite 30B (C 30B) as a solid hydrophilic proton conductor. PEMs were characterized using liquid uptake, oxidative stability, TGA, XRD, SEM, AFM and impedance analysis. The single cell DMFC performance reveals that the optimized PEM showed an open circuit voltage (OCV) of 0.79 V and a maximum power density value of 55 mW cm⁻² with a proton conductivity value in the range of 10⁻² S cm⁻¹. The methanol permeability and selectivity ratio of the optimized membrane were 1.35 × 10⁻⁷ cm² s⁻¹ and 9.63 × 10⁴ S s cm⁻³, respectively. As a result fabricated membranes could be seen as promising PEMs for DMFC applications.