Preparation and DMFC performance of polyetheretherketone polymer electrolyte membranes

Chen, J.; Li, D.*; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru

To meet the request of direct methanol fuel cells (DMFC), a highly thermal engineering aromatic polymer, polyetheretherketone (PEEK) film, was used as the base film to develop the polymer electrolyte membrane by radiation-grafting method. However, because of the low grafting activity of the PEEK chains, the styrenesulfonic ethyl ester (ETSS) monomer was difficult to directly graft to the PEEK film with request amounts. In this study, we first grafted a divinylbenzene (DVB) monomer into the PEEK film to form the radiation-active sites, through which ETSS can be easily grafted to the PEEK during the second radiation grafting step. As a result, new polymer electrolyte membranes with high proton conductivity and low methanol permeability were successfully developed. The new polymer electrolyte membrane was tested in a DMFC, showing a high power density.