The ionomer-catalyst interface and electrode pore structure have a considerable impact on electrochemical characteristics of anion exchange membrane fuel cell (AEMFC) because the reactant gas, water, and ion transport occur at such interface and pores. Generally, most anion exchange membranes and ionomers are hydrocarbon-based polymers. Due to their low hydrophobicity of main polymer chain compared to PFSA-based polymer like Nafion® for proton exchange membrane fuel cell (PEMFC), most anion exchange polymers have poorly developed water channels and low gas permeability. For this reason, fabrication of an effective catalyst layer plays a key role to enhance AEMFC performance and durability. Here, we observe the dispersion form of the commercially available anion-exchange polymer (I2, Acta), which changes according to three different alcohol-based dispersion media. Then, this solubilized anionic polymer solution is applied to AEMFC catalyst ink for electrode fabrication. The effect of the dispersion medium with different dielectric constants on the electrode pore structure is clearly confirmed by electrophoretic light scattering and mercury porosimetry, and the AEMFC performance of each electrode fabricated by catalyst ink using different solubilized anionic polymer solution is evaluated by polarization and electrochemical impedance spectroscopy. Finally, the characteristics of ionomer-catalyst interfaces are confirmed by carrying out comprehensive physical and electrochemical analysis.

Modification of catalyst-ionomer interface and pore structure by controlling anion-exchange ionomer dispersion

2019 Fall National Meeting

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