Cell performance of DMFC fabricated with H+-ETS-10/Nafion composite membrane
Abstract Zeolite/Nafion composite membrane was successfully cast using microporous titanosilicate, H+-ETS-10 and the cell performance of the MEA using this cast composite membrane was tested at 60 °C. Various H-ETS-10s with different % ion exchange rate were obtained through ion-exchange process using 0.02, 0.04 and 0.05 N HCl solution, respectively. In cases of H-ETS-10s with 80% and 90% of ion exchange rate, the proton conductivities became higher than of Nafion 115 and recasting membrane while the methanol permeability was lower than of Nafion 115, indicating the blocking effect against methanol permeation through membrane exerted by zeolite particles. Water uptakes on the membranes incorporated by various H-ETS-10s are directly proportional to % ion exchange rate of H-ETS-10 and its content in membrane, suggesting that the higher the % ion exchange rate is, the more the hydrophilicity is. In cases of incorporating H-ETS-10s with 80% and 90% of % ion exchange rates, the MEA fabricated with composite membrane with 5.0 wt.% of zeolite content shows the best cell performance among the MEAs with various zeolite contents from 1.5 to 5 wt.%, especially at high current density (i.e. >0.5 A/cm2). It is quite well consistent with characteristic factor. The enhanced cell performance is attributed to the incorporations of zeolite particles into Nafion dispersion.