Polyetheretherketone-based polymer electrolyte membranes for fuel cells prepared by radiation techniques

Chen, J.; Zhai, M.; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru

Polymer electrolyte membrane fuel cells are very promising as power sources for automotive applications, where stability and durability at a high temperature and low humidity are demanded. The currently used expensive Nafion membranes are not appropriated for application in high temperature fuel cells. For this reason, an inexpensive polyetheretherketone (PEEK)-based polymer electrolyte membrane (ssPEEK) was prepared by successive two-step grafting of divinylbenzene and ethyl styrenesulfonate onto PEEK film, followed by hydrolysis of the ETSS graft chains to form styrenesulfonate graft chains. The results of the fuel cell test showed that ssPEEK has a performance comparable to Nafion at lower temperature and higher humidify, and much better performance at higher temperature and lower humidify. In addition, at the latter, the ssPEEK-based cell could be operated with stable performance for more than 250 h without any substantial voltage drop, whereas the voltage of the Nafion-based cell continuously dropped over the same duration.