Cloisite- and bentonite-based stable nanocomposite membranes for enhancement of direct methanol fuel cell applications

Nanocomposite membranes were fabricated using sulfonated polyether ether ketone (SPEEK) by incorporating nanocalys of cloisite 30B and bentonite. The nanocomposite membranes with the thickness of 100 µm were successfully fabricated by phase inversion method. The membranes were characterized for their organic functional groups, morphological structure, thermal and physical properties under the influences of cloisite 30B and bentonite addition in SPEEK matrix. The presence of nanoclays was confirmed by the changes observed in the membrane morphology and improved glass transition temperature in pristine SPEEK membrane. The fuel cell performance of the membranes was determined by their water uptake capacity, methanol permeability and proton conductivity. The 0.5 wt.% addition of cloisite and bentonite in SPEEK showed 2.1% reduction of water uptake as compared to the pristine SPEEK membrane. The cloisite added SPEEK membrane showed the average proton conductivity of 3.05 x 10^-5 S cm^-1 at 80°C. Nevertheless, cloisite and bentonite incorporated SPEEK nanocomposite membranes demonstrated the reduced proton conductivity of 6.14% in the methanol permeability as compared to the pristine SPEEK membrane. Hence, the modified SPEEK nanocomposite membranes with cloisite and bentonite are being suggested to be a promising proton exchange membrane for direct methanol fuel cell.