Structural modification of electrode for anion exchange membrane fuel cell by controlling ionomer dispersion

Abstract

An appropriate electrode microstructure design should be necessary to achieve high-performance anion exchange membrane fuel cells (AEMFCs). In general, the electrodes are fabricated from catalyst slurries which contain self-assembled agglomerates of catalyst particles with ionomer dispersed in a solvent. Therefore, solvent nature greatly affects the microstructure of the electrode, such as the pore structure and the formation of triple-phase boundaries for electrochemical reactions. Here, we investigate the influence of solvent on the microstructure of I2 ionomer-based electrode and its performance using three alcohol-based solvents (ethanol, 2-propanol, and 2-methyl-2-propanol [tBuOH)) with different dielectric constants and similar boiling points. Various physical and electrochemical characterization confirmed that the electrode pore structure changes significantly depending on the type of solvent while the electrochemically active surface area hardly changes. Furthermore, the efect of the three electrodes with different pore structures on AEMFC performance is observed for anode and cathode, respectively. It is demonstrated that the porous electrode with large pores is more advantageous in performance than a dense electrode at both the anode and the cathode for AEMFC. Consequently, the membrane electrode assembly with porous tBuOH-based electrodes exhibits more than 40% higher performance (1.32 W cm À2 ) than dense ethanol-based electrodes (0.94 W cm À2 ). K E Y W O R D Sanion exchange membrane fuel cell, dispersion solvent, membrane-electrode assembly, porestructure Sungjun Kim and Chi-Yeong Ahn, contributed equally to this study.

Solvent Effects on the Catalyst Ink and Layer Microstructure for Anion Exchange Membrane Fuel Cells

“…It is likely that the quick evaporation/solidification during CL fabrication leads to the preservation of the morphological features of the ink. 53,54 The solvent effects on the CL microstructure are further quantified by characterizing the pore structures of CL. Figure 4e−g shows the cumulative pore area, differential intrusion, and porosity with respect to solvent composition.…”

“…The microstructures of CL and ink show a correlation between them. It is likely that the quick evaporation/solidification during CL fabrication leads to the preservation of the morphological features of the ink. , …”

Toward Scalable Production: Catalyst‐Coated Membranes (CCMs) for Anion‐Exchange Membrane Water Electrolysis via Direct Bar Coating

“…[6,10] However, the absorption of solvent and drying of the catalyst ink leads to swelling and shrinking of the membrane, which typically leads to severely wrinkled and instable catalyst layers [17,18] and thus causes significant production challenges. [9,19,20] While a sprayed layer-by-layer deposition of the catalyst directly onto the membrane has been demonstrated on the laboratory scale, [18,[21][22][23] spray coating may not be a cost-effective option for mass production [24] due to low deposition rates [19,25] and large amounts of required solvents. Large amounts of solvents entail more drying units and the resulting large amounts of ink mist [26] requires explosion protection in the coating line.…”

CoNi2O4 Coated on Activated Carbon Wheat Husk (ACWH) as a Novel Nano-Electrocatalyst for Methanol and Ethanol Electro-Oxidation

“…Alcoholic fuel cells consist of three main parts: the anode, cathode, and membrane [21,22]. Fuel electrochemical oxidation occurs on the anode and oxygen reduction occurs on the cathode [23].…”