High methanol resistant polyelectrolyte membrane based on semi crystalline Poly(ether ketone) with densely sulfonated side chain for direct methanol fuel cell
Abstract Different from the widely developed amorphous polyelectrolyte membrane materials, semi crystalline sulfonated poly(ether ketone) (PEK SPx) membranes composed of crystalline poly(ether ketone) main chain and densely sulfonated side chain are prepared. Wide angle X ray diffraction analysis indicates that these membranes manifest crystalline nature. The dimensional stability and methanol resistance of PEK SPx membranes are greatly enhanced by introduction of semi crystalline structure. The dimensional change in pure methanol at 60 degC and methanol permeability of PEK SP20 membrane is only 25.9% and 36 x 10 8 cm2 s 1, respectively. In addition, coupled with excellent thermal stability, oxidative stability, good mechanical property, satisfactory proton conductivity and distinct micro phase separation, PEK SP20 membrane exhibits considerable single cell performance. Overall, semi crystalline PEK SPx membranes are a promising new type of proton exchange membranes for application in direct methanol fuel cells.