Composite membrane of sulfonated poly(ether ether ketone) and sulfated poly(vinyl alcohol) for use in direct methanol fuel cells

We report a composite membrane consisting of sulfonated poly(ether ether ketone) and sulfated poly(vinyl alcohol). A systematic investigation of the composite membrane in terms of swelling behavior, ionic exchange capacity, methanol permeability and proton conductivity suggests their potential applications in direct methanol fuel cells. We find that both the proton conductivity and the methanol permeability decrease with increasing the sulfated-PVA content. It is noteworthy that the λ defined as the ratio of methanol permeability with 20 mol dm−3 methanol solution to the methanol permeability with 2 mol dm−3 methanol solution decreases from 12.9 to 0.31 as the sulfated-PVA content increases up to 100 wt.%. The performance of MEAs fabricated with these composite membranes with 2 and 8 mol dm−3 methanol solution also suggest their potential usage with high methanol concentration for DMFCs.