As the world transitions towards a carbon-neutrality and low-carbon economy, research in the field of fuel cells and water electrolysis for a hydrogen economy is actively progressing. Among them, research on AEM (Anion Exchange Membrane) attracts attention as it enables inexpensive non-precious metal catalysts through rapid oxygen reduction reactions.[1,2] However, critical challenges faced by AEM include CO₂ poisoning and low performance due to Pt catalyst adsorption by hydrocarbon ionomers.[3,4]

In this work, we tried to identify the effect of AEM's performance by controlling the ionomer's particle size in the cathode electrode using solvent-non-solvent mixtures. A Fumapem® commercial membrane (FAA-3-50, Fumatech) was used as an AEM. Four slurry compositions were prepared using NMP (N-Methyl-2-pyrrolidone) as a good solvent and ethylene glycol as a non-solvent in different ratios. The AEMFC (Anion Exchange Membrane Fuel Cell) performance was evaluated at 70°C and 100 % RH conditions by supplying H₂/O₂ at a flow rate of 1,000 sccm, respectively.

The results showed that the electrode with higher non-solvent content had the highest performance, with 1,250 mA/cm² @ 0.6 V. The electrode composed only of good solvent had slightly lower performance, with a 920 mA/cm² @ 0.6 V. The impedance spectroscopy shows that the non-solvent-based electrode exhibited the lowest HFR, and the resistance was improved by nearly 20% compared to the electrode made of only good solvent.

Overall, our research demonstrates that the morphology of the ionomer in the electrode has a significant impact on the AEMFC performance. We controlled the dispersion of the ionomer inside the electrode by controlling the solvent-non-solvent ratio and showed that the performance of the alkaline membrane fuel cell improved significantly with an increase in non-solvent content. Based on this, we introduce the results of electrochemical analysis according to the composition and chemical structure of the ionomer in the electrode.