A Rheo-Impedance investigation on the interparticle interactions in the catalyst ink and its impact on electrode network formation in a proton exchange membrane fuel cell

Mehrazi, Shirin; Homayouni, Taymaz; Kakati, Nitul; Sarker, Mrittunjoy; Rolfe, Philip; Chuang, Po-Ya Abel

doi:10.1016/j.apenergy.2024.122680

Cited by 1 publication

(2 citation statements)

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“…As the data in Figure 5b suggested, after being subjected to the simulated shear condition of 1000 s −1 for 10 s, only IC15SC20 is free from the loss of elastic connectivity while the others have lost a certain extent of the elastic response after the restructuring. The loss of the elasticity of the ionomer-Pt/C assemblage in the catalyst inks can be attributed to a spatial redistribution of the ionomer when subjected to high shear [17]. Given the attractive nature of these assemblages, it is reasonable to expect that restructuring would favor coalescence primarily due to ionomer aggregation and adsorption.…”

Section: Discussionmentioning

confidence: 99%

“…Two factors, the ionomer-to-carbon (I/C) weight ratio and solid content (SC), are commonly involved in the catalyst layer design process. In particular, the I/C ratio has been found to strongly impact the transport resistance via ionomer thin-film morphology and the agglomerate size [13][14][15][16][17][18]. The solid content, which governs the particle concentration, is often overlooked as its influence can be negligible under certain conditions.…”

Section: Introductionmentioning

confidence: 99%

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The Formation–Structure–Functionality Relationship of Catalyst Layers in Proton Exchange Membrane Fuel Cells

Yang,

Kakati,

Sarker

et al. 2024

Energies

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Understanding the relationship between the formation, structure, and functionality of catalyst layers is crucial for designing catalyst layers with specific high-current-density operations. In this study, we investigated the impact of the ionomer-to-carbon (I/C) ratio and solid content on transport properties. We conducted fuel cell performance and diagnostic measurements to demonstrate the combined effects of the I/C ratio and solid content on the mass transport, particularly oxygen transport. To elucidate the roles of the I/C ratio and solid content in catalyst layer formation, we utilized dynamic light scattering and rheological measurements. By analyzing the local and global structure of ionomer-Pt/C assemblages in the catalyst inks, we observed that the I/C ratio and solid content influence the competition between homo-aggregation and hetero-aggregation, the strengths of inter- and intra-cluster bonds, and the rigidity and connectivity of the particulate structure. Additionally, high-shear-application simulations tend to reduce the connectivity of the particulate network and induce cluster densification, unless the global structure is mechanically stable and resilient. Based on this understanding, we established the formation–structure–functionality relationship for catalyst layers, thereby providing fundamental insights for designing catalyst layers tailored to specific functionalities.

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Section: Discussionmentioning

confidence: 99%