Ammonia-assisted dehydrofluorination between PVDF and Nafion for highly selective and low-cost proton exchange membranes: a possible way to further strengthen the commercialization of Nafion

For the first time, dehydrofluorination reaction was detected between PVDF and Nafion in the presence of ammonia. Cross-linked networks were hence formed in the ammonia-modified Nafion + PVDF composite proton exchange membrane (PEM). They significantly enhanced the fuel resistance, thermal and mechanical stabilities, as well as the structural maintenance of the composite PEM. Meanwhile, at 80 degrees C, a slight increase in the proton conductivity of the composite PEM was also observed due to its improved water retention capability and the newly formed oxygen-containing functional groups. More importantly, such a highly selective Nafion-based PEM may have strong cost competitiveness in the market of commercial PEMs by virtue of the extremely low cost of PVDF (a dosage of up to 30-50 wt%) and ammonia.