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 °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.