Effects of Ionomer Carbon Ratio and Ionomer Dispersity on the Performance and Durability of MEAs

Abstract

Membrane‐electrode assemblies (MEAs) are fabricated using different catalysts and ionomers, in order to investigate the effects of these factors on the performance and stability of the polymer electrolyte membrane fuel cell (PEMFC). Platinum catalysts with different degrees of graphitization in the carbon support (less graphitized: Tanaka, more graphitized: RTX) are used. Perfluorosulfonic acid polymer‐based ionomers with water‐based or organic solvent‐based solvents are also prepared as binders for the electrode. The optimum composition of catalyst and ionomer is identified based on the results of cyclic voltammetry, electrochemical impedance spectroscopy, single cell performance, and long‐term durability tests. Tanaka catalyst and water‐based ionomer show the best performance and durability. In addition, the ionomer to carbon (I/C) weight ratio affects the fuel cell performance, and the optimum value is I/C = 1 for both water‐based and organic solvent‐based ionomers.

Engineering Catalyst Layers for Next‐Generation Polymer Electrolyte Fuel Cells: A Review of Design, Materials, and Methods

“…[ 255 ] Lee et al. [ 290 ] reported the optimal composition to change slightly depending on carbon and solvent, due to the specific interactions in the ink influencing structural composition. For electrodes with the same I/C ratio, an amorphous carbon support exhibited a larger mean pore size, porosity, effective oxygen diffusivity, and smaller tortuosity, after co‐deposition with ionomer, despite the PSD and porosities of the starting carbon particles being very similar.…”

“…Transmission electron microscopy (TEM) imaging is a key technique that has been used to investigate the ionomer distribution, with ionomer thickness estimated from observing the edges of carbon agglomerates in the micrographs. [ 64,290 ] Despite the high‐resolution nature of TEM, these boundaries can be somewhat difficult to resolve reliably, which raises questions about the accuracy of these measurements. Furthermore, sample deposition of small agglomerates onto a TEM gid may disrupt the ionomer distribution and the ultra‐high vacuum experimental conditions are far from representative of operational fuel cells.…”

Effectively Increasing Pt Utilization Efficiency of the Membrane Electrode Assembly in Proton Exchange Membrane Fuel Cells through Multiparameter Optimization Guided by Machine Learning

“…The I/C ratio should be neither too low nor too high to achieve a better performance. 19,31,32 As another parameter related to the composition of the ink, the water content in the ink would impact the evaporation rate of the solvent and have an impact on the flatness of the CL. Moreover, the addition of water prevents dangerous combustion when the pure organic solvent is mixed with highly active Pt/C in air.…”

“…The mass ratio of the ionomer to catalyst is vital to achieving a balance between proton conduction and electron conduction as well as the optimization of complicated interfaces, as has been studied in numerous works. The I/C ratio should be neither too low nor too high to achieve a better performance. ,, As another parameter related to the composition of the ink, the water content in the ink would impact the evaporation rate of the solvent and have an impact on the flatness of the CL. Moreover, the addition of water prevents dangerous combustion when the pure organic solvent is mixed with highly active Pt/C in air.…”

Covalent organic framework–based porous ionomers for high-performance fuel cells

“…3C). The electrochemical active surface area ( 31 ) of Pt/C@SDT-Nafion (67.4 m 2 g Pt −1 ) was also higher than that of the Pt/C@Nafion (41.4 m 2 g Pt −1 ) (fig. S19 and table S2).…”