Compared to fuel cells using proton exchangeable polymers, the direction of ion movement in the fuel cells using anion conducting polymer membranes shown in Figure 1 is opposite which is from cathode to anode. The hydroxyl ion movement mitigates overpotential for oxygen reduction reaction as well as water flooding at cathode. In addition, they overcome the disadvantages of alkaline fuel cells such as formation of carbonate precipitates, leakage of liquid KOH electrolyte, system complexity and so on by using solid electrolytes. Anion conducting ionomers are the polymers where anion exchangeable fixed groups, e.g., quaternary ammonium groups, are covalently attached to main backbones. It conducts the selective movement of anions which is allowed to be transported inside free volume of wet polymers. Much efforts are devoted to the development of anion conducting membranes as electrolytes of the fuel cell, but few researches on ionomer binder solutions for preparation of electrodes of membrane-electrode assemblies were carried out due to the technical difficulty in dispersing the polymers in various solvent systems. In this study, poly(phenylene oxide) (PPO) were brominated and in-situ quaternized by trimethyl ammonium during membrane casting. Once it was cast, it was hardly dispersed in any solvent system. Thus, the polymer was frozen by aqueous nitrogen and was ground by a blade-type grinder. Upon grinding time, the final forms were powders with different size of particle. The powder was used to prepare ionomer binder solutions, and the solutions (or dispersions) were characterized in terms of ion conductivity, ion exchange capacity, FT-IR, dynamic light scattering. In addition, the performance of membrane-electrode assemblies with the content of the ionomer with respect to I-V polarization, cyclic voltammetry, and impedance.

Acknowledgment

This work was supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20153030031720).