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Lee, Seon-Ho, Seunghee Woo, Yun Sik Kang, Seokhee Park e Sung-Dae Yim. "Evaluating Ink Structure Using Ultrasonic Spray Coating for PEMFC MEA". ECS Meeting Abstracts MA2023-02, n. 37 (22 dicembre 2023): 1739. http://dx.doi.org/10.1149/ma2023-02371739mtgabs.
Abstract (sommario):
From the standpoint of improving manufacturing productivity and performance/durability of PEMFC MEAs, there is an increasing interest in ink. Ink research is centered on comprehending the interplay between the components of the ink, including catalysts, ionomers, and solvents, to control the ink structure and evaluate its influence on ink properties, catalyst layer microstructure, and fuel cell performance. As a facet of this ink research, the current study proposes ultrasonic spray coating as a methodology to indirectly evaluate the ink structure. 50 wt% Pt/C catalysts loaded on Ketjenblack (KB) and Vulcan carbon (VC) were separately incorporated to produce sprayable inks with a solid content of 4 wt% using an Aquivion ionomer (EW 720) and a mixture solvent composed of a 1:1 weight ratio of 1-propanol and water. The structural differences between the two catalyst inks were compared by quantifying the amount of adsorbed and free ionomers, as well as their rheological properties. Additionally, the advantages of ultrasonic spray coating, such as the formation of small droplets on the order of tens of micrometers and rapid drying, were utilized to coat each ink onto a silicon substrate. The structural characteristics of the resulting catalyst layers were compared through SEM images, as well as the distribution of constituent elements using EDS and Auger spectroscopy. The Pt/KB catalyst ink forms a gel-like structure due to its relatively high amount of adsorbed ionomer, resulting in a relatively uniform distribution of catalyst particles and ionomers in the catalyst layer formed from ultrasonic spray droplets. In contrast, the Pt/VC catalyst ink behaves as a liquid-like, mainly existing in the form of free ionomer, regardless of ionomer content. During the drying process of each droplet, they merge to form larger unit catalyst layers, which exhibit an uneven distribution where free ionomers tend to concentrate at the edges of the catalyst layer due to the coffee-ring effect. As a result, the catalyst and ionomers exist in a non-uniform distribution, which is observed to affect the performance and electrochemical characteristics of fuel cells. In this presentation, we will discuss in detail the series of characteristics of ink-catalyst layer-fuel cell performance that vary according to catalyst properties.
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Liu, Guangxin, David McLaughlin, Simon Thiele e Chuyen Pham. "Linking Multicomponent Interactions of Catalyst Ink and Catalyst Layer Fabrication with Electrochemical CO2 Reduction Performance". ECS Meeting Abstracts MA2023-01, n. 38 (28 agosto 2023): 2238. http://dx.doi.org/10.1149/ma2023-01382238mtgabs.
Abstract (sommario):
The controllable fabrication of catalyst layers (CL) by tuning the multiscale structure formation is complex but vital to achieving optimum CO2 reduction (CO2R) performance. The CL formation is deeply influenced by catalyst ink. An in-depth understanding on the role of each catalyst ink component and how multicomponent interactions affect ink status, catalyst layer structure, and CO2R performance is crucial. In this work, the roles of various ingredients of catalyst ink were systematically investigated from simple binary inks to complete catalyst inks. Our results showed Ag agglomerates can be broken down more efficiently in water than in alcohols due to stronger inter-particle repulsive forces induced by water disassociation. Ag particles-Nafion networks were found to play a decisive role in stabilizing catalyst ink, mitigating agglomeration and particle sintering. The catalyst ink was comprehensively characterized and reported by static multiple light scattering (SMLS) for the first time in this study. The evolution of catalyst ink was identified in three stages: stable, flocculation and sedimentation. Isopropanol (IPA)-rich solvents were demonstrated to be more effective in stabilizing catalyst ink due to better dispersed Nafion aggregates and further enhanced Ag particle-Nafion interactions. Subsequently, catalyst layer structure and CO2R performance were correlated with multi-component interactions in catalyst ink. Strong Ag particle-Nafion interactions were proven to promote not only ink stability, but also catalyst layer homogeneity and reaction site distribution. Water-rich inks helped improve the porosity and durability of GDEs. The cathodic potential of GDEs made by 70%-water inks (-0.75 V vs. NHE) was 30% lower than zero-water inks (-1.1 V vs. NHE), and the highest CO selectivity was boosted to 97% at an industrial meaningful current density of 200 mA/cm2 by enhancing Ag particle-Nafion interactions through rational design of ink formulation, dispersing and fabrication processes. Simultaneously, a scalable manufacturing methodology of robust GDE was developed and validated to achieve optimal CO2R performance. It will not only provide a meaningful reference for lab applications (fast and reproducible GDE fabrication aiming at new catalysts, ionomers, membranes or operation conditions development), but also provide a steppingstone to industrial applications (GDE fabrication aiming at large scale, good durability and quality of conformance). Figure 1
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Du, Shaojie, Shumeng Guan, Shirin Mehrazi, Fen Zhou, Mu Pan, Ruiming Zhang, Po-Ya Abel Chuang e Pang-Chieh Sui. "Effect of Dispersion Method and Catalyst on the Crack Morphology and Performance of Catalyst Layer of PEMFC". Journal of The Electrochemical Society 168, n. 11 (1 novembre 2021): 114506. http://dx.doi.org/10.1149/1945-7111/ac3598.
Abstract (sommario):
The effects of dispersion method for ink preparation and types of catalyst on the catalyst layer’s structure and characteristics were investigated. Catalyst layers prepared by two dispersion methods, i.e., sonication and ball-milling, and two types of catalyst: Pt-HSC (High Surface Area) and Pt-Vulcan XC-72, were fabricated. Viscosity, particle size distribution of the catalyst inks, catalyst layer’s surface properties, and cell performance were measured. Experimental results with the Pt-HSC at ionomer/carbon weight ratio 0.8 show that ink dispersity strongly depends on the mixing method and large agglomerates form in the ink after sonication. The effect of the dispersion method on the ink prepared by Pt-Vulcan XC-72 at similar conditions is not noticeable. The catalyst layer’s mechanical properties, such as hardness and Young’s modulus, were found to vary widely. With an increase of catalyst layer thickness, the number of pin-holes decreased and cracks gradually increased in size. Polarization curves show that the membrane electrode assemblies (MEAs) made with 60% Pt-HSC have a better performance than those with 30% Pt-Vulcan XC-72. The performance and measured electrochemical active surface area of the MEAs made from both catalysts are slightly affected by dispersion method.
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Park, Jaehyung, Nancy N. Kariuki e Deborah J. Myers. "In-Situ X-Ray Scattering Study of Iridium Oxide Catalyst for Polymer Electrolyte Membrane Water Electrolyzer during Ink Sonication and Drying Process". ECS Meeting Abstracts MA2022-02, n. 39 (9 ottobre 2022): 1420. http://dx.doi.org/10.1149/ma2022-02391420mtgabs.
Abstract (sommario):
Polymer electrolyte membrane water electrolyzers (PEMWEs) offer greenhouse gas emission-free hydrogen production for fuel cell vehicles and other industrial uses when using renewable energy sources [1]. Unsupported iridium oxide (IrO2) is the most active stable oxygen evolution reaction (OER) catalyst utilized in the anode of the PEMWE [2]. The atomic and microstructure of IrO2 catalysts and electrodes and interactions between and ionomer and catalyst can affect the ultimate performance of the PEMWE anode. These properties and phenomena may be controlled by the interactions of the ionomer in the catalyst-ionomer ink, by the effect of ink solvent composition on those interactions, and by the ink mixing and coating procedures. The microstructure evolution of the IrO2 catalyst during ink processing has not yet been identified. This presentation will describe relationships between ink formulation, electrode morphology, and performance for the IrO2-based PEMWE anodes. Moreover, the results of the evolution of the catalyst layer during the ink drying process as a function of solvent removal rate and solvent identity will be discussed. This study uses the in-situ technique of ultra-small angle X-ray scattering (USAXS) combined with small angle X-ray scattering to determine particle size distributions and the extent of IrO2 agglomeration in the inks and electrodes during the ink mixing/settling and drying processing. The effects of ionomer concentration, catalyst concentration, and solvent composition on the microstructure of the catalyst inks and electrode are correlated with the PEMWE performance and operando diagnostic data. Acknowledgements This work was supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the H2NEW Consortium. This work was authored in Argonne National Laboratory, a U.S. Department of Energy (DOE) Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357. This research used the resources of the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. References [1] M. Carmo, D. L. Fritz, J. Mergel, D. Stolten, A Comprehensive Review on PEM Water Electrolysis, Int. J. Hydrogen Energy 2013, 38, 4901−4934. [2] H. Yu, N. Danilovic, Y. Wang, W. Willis, A. Poozhikunnath, L. Bonville, C. Capuano, K. Ayers, R. Maric, Nano-size IrOx catalyst of high activity and stability in PEM water electrolyzer with ultra-low iridium loading, Applied Catalysis B: Environmental 2018, 239, 133-146.
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Sasabe, Takashi, Toshihiko Ogura, Koki Okada, Haruto Oka, Katsunori Sakai e Shuichiro Hirai. "Influence of Ethanol Decomposition on Dispersion of PEFC Catalyst Ink". ECS Transactions 112, n. 4 (29 settembre 2023): 93–99. http://dx.doi.org/10.1149/11204.0093ecst.
Abstract (sommario):
To achieve high power density operation of polymer electrolyte fuel cells (PEFCs), it is required to realize higher performance catalyst layer. Because dispersion structure of catalyst ink strongly affects the catalyst layer structure, it is crucial to understand the dispersion mechanism of PEFC catalyst ink. Though water/ethanol solution is used as solvent of the catalyst ink, decomposition of ethanol by Platinum catalyst strongly affect dispersion of the catalyst ink. In this study, influence of ethanol decomposition on dispersion of catalyst inks were investigated. Among the decomposition byproducts of ethanol, results of rheology characteristics and direct observation by scanning electron assisted dielectric microscopy clearly showed that acetaldehyde has a significant impact on aggregation of catalyst ink. To reveal the mechanism of aggregation, particle size measurement and ionomer adsorption fraction measurement of the catalyst ink were carried out. The results suggested that the acetaldehyde impede adsorption of the ionomer on Platinum catalyst.
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Khandavalli, Sunilkumar, Jaehyung Park, Robin Rice, Guido Bender, Deborah J. Myers, Michael Ulsh e Scott A. Mauger. "Tuning the Rheology of Anode Inks with Aging for Low-Temperature Polymer Electrolyte Membrane Water Electrolyzers". ECS Meeting Abstracts MA2022-02, n. 40 (9 ottobre 2022): 1483. http://dx.doi.org/10.1149/ma2022-02401483mtgabs.
Abstract (sommario):
Low-temperature polymer electrolyte membrane water electrolyzers (PEMWE) are an attractive clean energy technology to produce hydrogen (H2), which is an energy carrier for several applications such as transportation and grid-scale energy storage and distribution (as supported by the US Department of Energy’s H2@Scale initiative). The catalyst layers -- composed of catalyst particles and ionomer, which acts as a binder for the catalyst and a proton conducting medium -- are key components of the PEMWE membrane electrode assembly (MEA). The catalyst layers are commonly fabricated by solution-processing an ink, which is a mixture of catalyst and ionomer often dispersed in a water-alcohol solvent mixture. Tuning the rheological properties of the anode inks (typically composed of iridium oxide catalyst, IrOx), particularly increasing their viscosity without significantly increasing the solids loading, to suit various scalable coating methods, is generally a challenge due to relatively low porosity and high density of the IrOx catalysts compared to the carbon-supported cathode catalysts. The typically low viscosities of the anode inks combined with high particle densities often cause stability/settling issues and challenges obtaining unform coatings, leading to inhomogeneous distribution of the catalyst that may have a negative effect on electrode performance. In this presentation we report on a dramatic enhancement in the viscoelasticity of the anode inks with aging, where the ink transitions from a liquid-like to a weak gel-like structure. The steady-shear and oscillatory shear rheology characterizations of the inks as a function of aging/time, the impact of formulation conditions (ionomer-to-catalyst ratio and dispersion media composition) on the viscoelastic enhancement with aging, and possible mechanisms for the observed behavior will be discussed. In addition to the rheological measurements, X-ray scattering characterization of the ink structure will be presented. The implications of the rheological changes on ink stability and processing will also be discussed. Additionally the impact of ink age on MEA performance will be presented.
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Sasabe, Takashi, Toshihiko Ogura, Koki Okada, Haruto Oka, Katsunori Sakai e Shuichiro Hirai. "Influence of Ethanol Decomposition on Dispersion of PEFC Catalyst Ink". ECS Meeting Abstracts MA2023-02, n. 37 (22 dicembre 2023): 1740. http://dx.doi.org/10.1149/ma2023-02371740mtgabs.
Abstract (sommario):
To achieve high power density operation of polymer electrolyte fuel cells (PEFCs), it is required to realize high-performance catalyst layer with low oxygen transport resistance, high proton and electron conductivities, and high electrochemical surface area (ECSA) with low Platinum loading. Because dispersion structure of catalyst ink strongly affects porous structure of the catalyst layer, it is crucial for realization of high-performance catalyst layer to understand the dispersion mechanism of the catalyst ink. Our group has reported that decomposition of ethanol, as a solvent, by platinum catalyst significantly affects aggregation of the catalyst ink. [1, 2] But, the mechanism of the catalyst ink aggregation was not fully understood. In this study, effect of ethanol decomposition on the aggregation of the catalyst ink was investigated. The catalyst ink was fabricated by mixing platinum-supported carbon (TEC10V30E, Tanaka Kikinzoku), ionomer (DE1021, Sigma-Aldrich), and water/ethanol solvent (water/ethanol: 60/40 wt%). Decomposition product of ethanol within the catalyst ink solvent was analyzed by GC/MS (GCMS-QP2020NX, SHIMADZU), and presence of acetaldehyde (C2H4O) and acetic acid (CH3COOH) was detected. In order to investigate the influence of these products on aggregation of the catalyst ink, acetaldehyde or acetic acid was added to the catalyst ink. The particle size distribution was evaluated by using laser diffraction type particle size distribution meter (LA-960V2, HORIBA) without dilution, and it was confirmed that the acetaldehyde-added catalyst ink showed larger particle size and the acetaldehyde caused the aggregation of the catalyst ink (Figure 1). In addition, dispersion of the catalyst ink was observed by using an optical microscopy, and aggregation of the catalyst ink by adding the acetaldehyde was clearly observed (Figure 2). To understand the aggregation mechanism by adding acetaldehyde, ionomer adsorption fraction on the platinum-supported carbon was measured by using centrifugation method, and the decrease in ionomer adsorption fraction by adding acetaldehyde was confirmed. From these results, it was confirmed that acetaldehyde generated by the decomposition of ethanol in the catalyst ink leads to a decrease in the ionomer adsorption fraction. It is reported that the ionomer promotes the dispersion of platinum-supported carbon due to electrostatic repulsion forces, and it is suggested that the decrease in ionomer adsorption fraction results in the aggregation of the catalyst ink. Therefore, to realize high-performance catalyst layer, influence of acetaldehyde should be minimized and further research is requested to understand it. Acknowledgement This presentation is based on results obtained from a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References [1] Takashi Sasabe et al., ECS Trans. 104, 191 (2021). [2] Takashi Sasabe et al., ECS Meeting Abstracts 242, 1433-1433 (2022). Figure 1
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Liu, Huiyuan, Linda Ney, Nada Zamel e Xianguo Li. "Effect of Catalyst Ink and Formation Process on the Multiscale Structure of Catalyst Layers in PEM Fuel Cells". Applied Sciences 12, n. 8 (8 aprile 2022): 3776. http://dx.doi.org/10.3390/app12083776.
Abstract (sommario):
The structure of a catalyst layer (CL) significantly impacts the performance, durability, and cost of proton exchange membrane (PEM) fuel cells and is influenced by the catalyst ink and the CL formation process. However, the relationship between the composition, formulation, and preparation of catalyst ink and the CL formation process and the CL structure is still not completely understood. This review, therefore, focuses on the effect of the composition, formulation, and preparation of catalyst ink and the CL formation process on the CL structure. The CL structure depends on the microstructure and macroscopic properties of catalyst ink, which are decided by catalyst, ionomer, or solvent(s) and their ratios, addition order, and dispersion. To form a well-defined CL, the catalyst ink, substrate, coating process, and drying process need to be well understood and optimized and match each other. To understand this relationship, promote the continuous and scalable production of membrane electrode assemblies, and guarantee the consistency of the CLs produced, further efforts need to be devoted to investigating the microstructure of catalyst ink (especially the catalyst ink with high solid content), the reversibility of the aged ink, and the drying process. Furthermore, except for the certain variables studied, the other manufacturing processes and conditions also require attention to avoid inconsistent conclusions.
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Sasabe, Takashi, Toshihiko Ogura, Koki Okada, Katsunori Sakai e Shuichiro Hirai. "(Digital Presentation) Investigation on Effects of I/C Ratio on Dispersion Structure of PEFC Catalyst Ink By Scanning Electron Assisted Dielectric Microscopy". ECS Meeting Abstracts MA2022-02, n. 39 (9 ottobre 2022): 1433. http://dx.doi.org/10.1149/ma2022-02391433mtgabs.
Abstract (sommario):
To achieve high power density operation of polymer electrolyte fuel cells (PEFCs), it is required to realize higher performance catalyst layer with low oxygen transport resistance, high proton conductivity, and low Platinum loading. Because dispersion structure of catalyst ink strongly affects the catalyst layer structure, it is crucial to understand the dispersion mechanism of PEFC catalyst ink. We have reported that that solvent composition (ethanol concentration) of the catalyst ink strongly affect dispersion of the catalyst ink [1, 2], but effects of other components on the dispersion of the catalyst ink were not fully understood yet. In this study, effect of I/C ratio (amount of ionomer) on the dispersion of the catalyst ink was investigated. The catalyst inks were fabricated by mixing platinum-supported carbon (TEC10V30E, Tanaka Kikinzoku), ionomer (DE1021, Sigma-Aldrich), and water/ethanol solvent. To investigate the effect of ionomer on dispersion of the catalyst ink, solvent compositon (ethanol/water = 20/80 wt%), amount of the platinum-supported carbon and solid content of the catalyst ink were kept constant., and the I/C ratio was changed from 0.25 to 1.25. Viscosity characteristics were measured at each shear rate in the range of 0.01 to 1000 1/s by a rotary rheometer (MCR302, Anton-Paar), and particle size distribution of the catalyst ink was measured by the laser diffraction type particle size distribution meter (LA-960V2, HORIBA) without any dilution. In addition, we have succeeded to directly observe the dispersion structure of the catalyst ink by using a scanning electron assisted dielectric microscopy (SE-ADM) for the first time. SE-ADM enabled observation of the catalyst ink with very little radiation damage and high-contrast imaging without staining or fixation at an 8-nm spatial resolution, and distribution of the platinum-supported carbon, ionomer, and solvent were clearly observed. Figure (a) showed the effects of I/C ratio on aggregation size. The result clearly showed that the catalyst inks with too less (I/C=0.25) or too much (I/C=1.25) amount of ionomer were aggregated. Figure (b) showed the results of SE-ADM imaging. Because the dielectric constant of materials within the catalyst ink were different, the image clearly visualized distribution of the platinum-supported carbon, ionomer, and solvent, and the visualization results of the catalyst ink with different I/C ratio were consistent with the results of the particle size distribution measurement. Though the ionomer works as a surfactant within the catalyst ink, too much ionomer makes the dispersion of the catalyst ink worth, and tuning the amount of ionomer is important to realize the high performance catalyst layer. Acknowledgement This presentation is based on results obtained from a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). [1] Kaname Iida et al. 2020 ECS Trans. 98, 497. [2] Takashi Sasabe et al. 2021 ECS Trans. 104, 191. Figure 1
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Karaca, Ali, Andreas Glüsen, Klaus Wippermann, Scott Mauger, Ami C. Yang-Neyerlin, Steffen Woderich, Christoph Gimmler et al. "Oxygen Reduction at PtNi Alloys in Direct Methanol Fuel Cells—Electrode Development and Characterization". Energies 16, n. 3 (19 gennaio 2023): 1115. http://dx.doi.org/10.3390/en16031115.
Abstract (sommario):
Catalyst layers made from novel catalysts must be fabricated in a way that the catalyst can function to its full potential. To characterize a PtNi alloy catalyst for use in the cathode of Direct Methanol Fuel Cells (DMFCs), the effects of the manufacturing technique, ink composition, layer composition, and catalyst loading were here studied in order to reach the maximum performance potential of the catalyst. For a more detailed understanding, beyond the DMFCs performance measurements, we look at the electrochemically active surface area of the catalyst and charge-transfer resistance, as well as the layer quality and ink properties, and relate them to the aspects stated above. As a result, we make catalyst layers with optimized parameters by ultrasonic spray coating that shows the high performance of the catalyst even when containing less Pt than commercial products. Using this approach, we can adjust the catalyst layers to the requirements of DMFCs, hydrogen fuel cells, or polymer electrolyte membrane electrolysis cells.
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Choi, Hyunguk, Won young Choi, Seo Won Choi, MyeongHwa Lee, Young Je Park, Nam Jin Lee, Kwang Shik Myung et al. "Advanced Decal Transfer in PEFC Electrode: Effect of Rheology Catalyst Inks and Decal Substrate Property". ECS Meeting Abstracts MA2022-02, n. 44 (9 ottobre 2022): 1658. http://dx.doi.org/10.1149/ma2022-02441658mtgabs.
Abstract (sommario):
To address the global climate change issues, polymer electrolyte fuel cells (PEFCs) are receiving attention as electrochemical energy conversion devices employing green hydrogen. Notably, the PEFC fuel cell is because the electrochemical reaction occurs on the Catalyst Layer (CL), the CL is the core of the Membrane Electrode Assembly (MEA). The conventional CL is usually prepared from catalyst ink comprising the various catalyst, ionomer, and solvents and deposited via blade coating to the decal substrate. Therefore, it is necessary to confirm the optimal decal transfer conditions based on analyzing the characteristics of the catalyst ink and the decal substrate. In the study, the characterize the internal microstructure of the catalyst ink was confirmed through rheology, and the coating velocity was tunable based on catalyst property. In addition, the characteristics of the various decal substrate were confirmed through Atomic Force Microscopy (AFM) and Contact Angle, and differences including variations in loading amount were confirmed despite the same slurry. The structure of CL on the decal sheet was confirmed through a scanning electron microscope (SEM) surface image and cross-section image, and the distribution of Pt and ionomer was confirmed through Energy Dispersive X-Ray Spectrometer (EDS) mapping. The definition of electrochemical performance between catalyst ink characterizes and decal substrates property was investigated through polarization curves and electrochemical impedance spectroscopy (EIS). Also, cyclic voltammetry (CV) techniques are used to characterize electrochemical surface areas (ECSA) areas of the CL. As a result, the property between the catalyst ink and the decal substrate, based on the difference that occurs in the rheology characterized in the catalyst ink, leads to a variation in the CL structure. Therefore, it is very important to determine the decal process conditions by understanding the characteristics of various catalyst ink on rheology and decal sheet.
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Li, Chenzhao, Shengwen Liu, Yachao Zeng, Yadong Liu, David A. Cullen, Gang Wu e Jian Xie. "Rationally Designed PGM-Free Catalyst MEA with Extraordinary Performance". ECS Meeting Abstracts MA2022-02, n. 40 (9 ottobre 2022): 1487. http://dx.doi.org/10.1149/ma2022-02401487mtgabs.
Abstract (sommario):
Platinum group metal (PGM) catalysts are the major electrocatalysts for oxygen reduction reaction (ORR) in the polymer electrolyte membrane fuel cells (PEMFCs). However, the high cost of PGM catalysts is the major huddler for the widespread applications of fuel cell electric vehicles. To remove this cost obstacle of fuel cell commercialization, PGM-free catalysts have been considered as the replacement of PGM catalysts for ORR because of the low cost and relatively comparable performance with PGM catalyst. Fe-C-N complex is the one of the most active centers in PGM-Free catalyst groups. This type of catalyst shows excellent activity characterized using the rotation disk electrode (RDE), i.e., the half wave potential (E1/2 ) could reach 0.91 V versus standard hydrogen electrode (SHE). However, in a membrane electrode assembly (MEA), the performance of PGM-Free catalysts cannot achieve the comparable performance to PGM catalyst. Since there are so many differences between PGM-free, and PGM catalysts e.g., activity, stability, surface conditions, particle size etc. The fabrication of PGM-Free catalyst MEA cannot simply borrow the methods from that of making PGM MEA. In addition, the thicknesses of catalyst layers of PFM-free are significantly thicker than that of PGM, i.e., 10 times. Hereby, we proposed a novel method of fabricating PGM-Free catalyst MEA, so that the intrinsic catalyst activity from RDE can be translated into MEA performance. The method is based on the catalyst coated membrane (CCM) method using optimized ionomer to carbon (I/C) ratio and solvent mixture of catalyst ink. Such method pushes PGM-free MEA first ever achieved the current density of 50.8 mA cm-2 at 0.9 V iR-free in H2/O2 and over 150 mA cm-2 at 0.8 V in H2/air, which surpassed the 2025 performance targets of US Department of Energy (DOE) for PGM-Free catalyst MEA. Further, the property (solvent composition, dispersion of catalyst and ionomer in an ink), structure (pore structure) and the MEA performance have been characterized using mercury intrusion porosimetry (MIP), MEA testing. A property-structure-performance relationship has been established.
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Kircher, Mario, Michaela Roschger, Wai Yee Koo, Fabio Blaschke, Maximilian Grandi, Merit Bodner e Viktor Hacker. "Effects of Catalyst Ink Storage on Polymer Electrolyte Fuel Cells". Energies 16, n. 19 (9 ottobre 2023): 7011. http://dx.doi.org/10.3390/en16197011.
Abstract (sommario):
The shelf-life of catalyst ink for fabricating polymer electrolyte fuel cells (PEFCs) is relevant for large-scale manufacturing with unforeseen production stops. In this study, the storage effects on the physicochemical characteristics of catalyst ink (Pt/C, Nafion, 2-propanol, water) and subsequently manufactured catalyst layers are investigated. Sedimentation analysis showed that catalyst particles are not fully stabilized by charge interaction induced by Nafion. Acetone was found to be an oxidation product, even in freshly prepared ink with platinum catalyzing the reaction. Rotating disk electrode analysis revealed that the electrochemically active surface area is, overall, minimally increased by storage, and the selectivity towards water formation (4-electron pathway) is unharmed within the first 48 h of storage. MEAs prepared from stored ink reach almost the same current density level after conditioning via potential cycling. The open-circuit voltage (OCV) increases due to increased catalyst availability. Scanning electron microscopy and mercury intrusion porosimetry showed that with increasing acetone content, the pore structure becomes finer, with a higher specific surface area. Electrochemical impedance spectroscopy revealed that this results in a more hindered mass transfer but lowered charge transfer resistance. The MEA with the highest OCV and power output and the lowest overall cell resistance was fabricated from catalyst ink stored for a duration of four weeks.
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Henke, Kira Viktoria, Henning Weinrich, Hermann Tempel e Rüdiger-A. Eichel. "Development of a Simple Ink Coating Procedure for BiVO4 Photoanodes for Oxygen Evolution". ECS Meeting Abstracts MA2023-02, n. 47 (22 dicembre 2023): 2285. http://dx.doi.org/10.1149/ma2023-02472285mtgabs.
Abstract (sommario):
Photoelectrodes can be implemented in electrochemical cells to accelerate the reaction kinetics of the intended reactions, utilizing the support of visible light. Especially, photoanodes for the oxygen evolution reaction (OER) are of great interest for energy storage and conversion, since the OER is the anodic half-cell reaction of many Power-to-X technologies such as water splitting, CO2 electroreduction and metal-air battery recharge. However, the OER still limits their potential by being a kinetically hindered 4-electron transfer process. In previous research, bismuth vanadate (BiVO4) has shown significant advances for the onset potential and increase in current density of the OER under illumination. Additionally, BiVO4 is a low-cost material, making it favorable over commonly used noble metal electrocatalysts, leading to its rise as one of the most suitable photoelectrocatalysts for OER photoanodes. However, BiVO4 still does not match practical requirements, demanding for further research and development. In this work, we focus on the implementation of a simple ink coating procedure for BiVO4 photoanodes. Ink coating demonstrates a versatile and adaptable preparation procedure for photoelectrodes, since photoelectrocatalyst synthesis and catalyst deposition are decoupled, providing a large degree of preparative freedom. On the one hand, the catalyst synthesis can be modified and adjusted separately. On the other hand, the catalyst deposition can be performed via various techniques using an ink. Thus, the photoelectrode preparation is not restricted to a certain substrate and specific synthesis conditions. In the proposed ink coating procedure, first neat and (Mo or W)-doped BiVO4 photoelectrocatalysts are prepared via hydrothermal synthesis also including Co-Pi as a post-deposited co-catalyst. Afterwards, the resulting catalysts are deposited onto FTO glass for further physico-chemical characterization. Moreover, the photoelectrochemical (PEC) performance under illumination and in the dark is investigated for the prepared electrodes. Finally, the ink coated electrodes are compared to BiVO4 photoanodes, which are prepared via solution-based methods, as reported in literature.[1-4] For the physico-chemical analysis, the ink coated photoanodes are characterized by various microscopic and spectroscopic techniques. SEM images reveal that homogeneous catalyst layers are prepared. Additionally, LSM measurements show that ink coating leads to a catalyst layer with a high surface roughness. XRD and Raman measurements reveal crystalline and pure BiVO4 structures. Furthermore, for the investigation of the PEC performance, an H-cell which is equipped with an LED light source is utilized, allowing for rapid and flexible data acquisition at constant temperatures. In the photoelectrochemical measurements, a significant reduction of the OER onset potential as well as a significant increase in photocurrent density in comparison to dark scans is achieved for neat BiVO4 photoanodes. For now, the ink coated BiVO4 could lower the onset potential by up to 0.6 V under illumination and increase the current density by up to 10 mA/cm² in comparison to the dark scans. In addition, modification of the ink coated BiVO4 by doping and co-catalyst deposition results in an even higher enhancement of the PEC performance for the OER. At this, the ink coated catalyst layers show an excellent stability even after several hours of PEC measurements. Moreover, it is shown that the ink coated BiVO4 photoanodes perform well in comparison to the solution coated electrodes. Overall, the ink coating procedure was successfully established for BiVO4 photoanodes, opening the door for the adaptation to the electrode preparation for different Power-to-X technologies. Literature: [1] B. Pattengale, J. Ludwig, J. Huang, J. Phys. Chem. C 2016, 120, 1421.; [2] S. K. Choi, W. Choi, H. Park, Phys. Chem. Chem. Phys. 2013, 15, 6499.; [3] J. A. Seabold, K.-S. Choi, J. Am. Chem. Soc. 2012, 134, 2186.; [4] K. J. McDonald, K.-S. Choi, Energy Environ. Sci. 2012, 5, 8553.
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Wang, Liping, Jianchao Lee, Meijuan Zhang, Qiannan Duan, Jiarui Zhang e Hailang Qi. "Fluorescence imaging technology (FI) for high-throughput screening of selenide-modified nano-TiO2 catalysts". Chemical Communications 52, n. 14 (2016): 2944–47. http://dx.doi.org/10.1039/c5cc10436j.
Abstract (sommario):
A high-throughput screening (HTS) method based on fluorescence imaging (FI) was built and applied to evaluate the catalytic performance of selenides-modified TiO2. A catalyst library comprising 1405 catalysts was established using color ink-jet printing technology.
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Hirose, Soichiro, Kosuke Takasugi, Trang Nakamoto e Kozo Taguchi. "Cobalt-Intercalated Birnessite-Type Manganese Oxide Catalysts for Low-Cost Cathodes in Microbial Fuel Cells". Resourceedings 3, n. 3 (31 dicembre 2023): 17–22. http://dx.doi.org/10.21625/resourceedings.v3i3.1025.
Abstract (sommario):
Microbial fuel cells (MFCs) are a promising technology for solving energy and water pollution problems. However, to promote the practical application of MFC, it is necessary to solve the problems of power output and electrode cost simultaneously. Therefore, transition metal-based catalysts that can improve air cathode functionality without using platinum catalysts, which are commonly used, are attracting attention. In this experiment, a cobalt-intercalated birnessite-type manganese oxide catalyst was used as the cathode of the MFC. In addition, rice husk charcoal from agricultural waste and Sumi ink were used as cathode materials to reduce cost and improve the physical stability of the electrodes. The conductivity of the Sumi ink is expected to compensate for the low conductivity of manganese oxide. The resulting power density was 5.8 times higher with the catalyst than without. It was also confirmed that the fabricated cathode operated for at least 90 days without maintenance.
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Choi, Won young, Hyunguk Choi, Seo Won Choi, Young Je Park, CHI-Young Jung, Nam Jin Lee, Jong min Lee e Young Gi Yoon. "The Ionomer Molecular Structure Effect in the PEFC Ink & Applications". ECS Meeting Abstracts MA2022-02, n. 41 (9 ottobre 2022): 1516. http://dx.doi.org/10.1149/ma2022-02411516mtgabs.
Abstract (sommario):
The interaction between the perfluorosulfonic acid (PFSA) ionomer and platinum group metal (PGM) catalyst in polymer electrolyte fuel cell (PEFC) inks is a critical issue for designing high-performance PEFC electrodes. During the ink fabrication, the complex interparticle interaction of the ink components determines the agglomerate morphology and size distribution. Among the ink components, the ionomer, which has amphiphilic in nature due to its hydrophobic backbone and the hydrophilic ionic group, mostly effective parameter for interparticle interaction. Therefore, understanding the interaction and molecular structure of ionomer is required for a high-performance catalyst layer. The backbone length of the ionomer which controls the spacing between ionic pendant groups is the main parameter of the ionomer character. In this study, the three different ionic spacing ionomers, made in the Solvay industry: Aquivion D72-25BS, Aquivion D83-24BS, and D98-25BS, were used for investigating the adsorption behavior of the catalyst ink and PEFC catalyst layer morphology. During the fabrication of PEFC ink and catalyst layer, all samples have same sulfonic acid molality to avoid the ionic clustering effect in the side chain. Ex-situ measurements were carried out to quantify the interparticle interaction and agglomerate size distribution in the PEFC ink. The dynamic lights scattering (DLS) carry out to determine the aggregation size distribution. The rheological behavior was conducted to understand the interparticle interactions and the agglomeration behavior of the inks by steady-shear and dynamic-oscillatory-shear measurements. It is noted that increasing the ionomer backbone length, which favors interaction via hydrophobic interaction on a carbon support, suppresses the agglomeration of ink components and decreases ink viscosity. The in situ electrochemical tests were carried out to figure out the relationship between ink formulation and catalyst layer morphology. It was found that the long ionomer backbone length helps to suppress the O2 transport resistance and ORR kinetic loss by uniform distribution from ionomer backbone-carbon supports interaction.
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Park, Jaehyung, Nancy N. Kariuki e Deborah J. Myers. "Microstructure Characterization of Catalysis Layers during Ink Drying Process for Polymer Electrolyte Membrane Fuel Cells". ECS Meeting Abstracts MA2022-01, n. 35 (7 luglio 2022): 1417. http://dx.doi.org/10.1149/ma2022-01351417mtgabs.
Abstract (sommario):
A catalyst ink for proton exchange membrane fuel cells (PEMFCs) is generally prepared by various mixing methods by dispersing platinum or platinum alloy nanoparticles supported on carbon blacks with ionomers in a specific solvent or solvent combination. The catalyst ink is deposited on the surface of the membrane or diffusion media and is typically subjected to elevated temperatures to facilitate rapid removal of solvent. Large carbon agglomerates resulting from sub-optimal ink dispersion and drying conditions can limit catalyst utilization, inhibit mass transport in the catalyst layer, and damage the membrane and possibly also the gas diffusion media [1, 2]. Micro-structural evolution of the catalyst ink can be controlled by interactions of the ionomer in the catalyst-ionomer ink and by the effect of ink solvent composition on those interactions during the ink drying process. This presentation will describe the results of in-situ/ex-situ X-ray scattering studies of the evolution of the cathode catalyst layer during the ink drying process to determine the impact of solvent removal rates and solvent identity on the structural evolution of the cathode catalyst layer. These studies also included operando ink drying at room temperature, under an atmosphere containing the solvent, and a high temperature. Ultra-small angle X-ray scattering (USAXS) was used to measure the agglomerate size distribution during the ink drying. A small environmental chamber was used to examine drying phenomena of high solid-content inks and dispersions to determine structural evolution during ink drying. The effects of ionomer concentration, catalyst concentration, and solvent composition on the microstructure of the catalyst inks and electrode are correlated with the MEA performance and operando diagnostic data. The goal of these studies is to guide the MEA fabrication process to optimize MEA performance and durability. References [1] I. V. Zenyuk, N. Englund, G. Bender, A. Z. Weber and M. Ulsh, J. Power Sources 332 (2016), 372–382. [2] M.Wang, J.Park, S. Kabir, K. C. Neyerlin, N. Kariuki, H. Lv, V. R. Stamenkovic, D. J. Myers, M. Ulsh, and S. A. Mauger, ACS Applied Energy Materials 2 (2019), 6417-6427 Acknowledgements Argonne National Laboratory is managed for the U.S Department of Energy (DOE) by the University of Chicago Argonne, LLC, under contract DE-AC-02-06CH11357. This work was authored in part by Alliance for Sustainable Energy, LLC, the manager and operator of the National Renewable Energy Laboratory for the U.S. DOE under Contract No. DE-AC36-08GO28308. This research used the resources of the Advanced Photon Source (APS), a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This research is conducted under the auspices of the Million Mile Fuel Cell Truck (M2FCT) Consortium (https://millionmilefuelcelltruck.org), which is supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office.
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Cho, Minju, Sung Yong Cho, Youngick Cho, Ji-Eun Lee, Sungchul Lee, Eun-Byeol Park, Young-Min Kim e Eun Heui Kang. "The Porous Structure Design of Catalyst Layer by Controlling Particle Size Distribution of PEMFC Catalyst Ink". ECS Meeting Abstracts MA2023-02, n. 37 (22 dicembre 2023): 1736. http://dx.doi.org/10.1149/ma2023-02371736mtgabs.
Abstract (sommario):
A general catalyst ink of proton exchange membrane fuel cells(PEMFC) consists of a catalyst, its support, an ionomer, and a solvent. These elements are made in the form of membrane electrode assembly(MEA) through grinding, dispersing, and coating processes. Therefore, the preparation of catalyst ink is an important step that directly affects the structure formation of the catalyst layer and the cell performance. In this study, by controlling the particle size distribution of the catalyst ink, we aim to achieve optimized pore structure in the catalyst layer that leads to improved performance of the fuel cell. Particle size and its distribution of the catalyst ink were confirmed by using particle size analyzer(PSA). Mercury intrusion porosimetry(MIP) was used to determine porous structure, including the pore diameter and total pore volume of MEA. Segmented tomographic evaluation is utilized to evaluate the 3D porous carbon structure in terms of local surface area, pore size distribution, and their 3D networking. MEA were tested to ascertain the influence of the catalyst ink properties on electrochemical character such as H2/air polarization curves, electrochemical impedance spectroscopy(EIS). Also, to analyze the resistance contributed by the molecular and Knudsen diffusion and permeation through the ionomer film, we tested MEA using limiting-current measurements. As a result, We are able to confirm that the particle size has a high correlation with the pore characteristics of the electrode layer that affect the cell performance. The enhanced electrochemical performance is attributed by decreasing fine particles about 0.1um in size. We figured out that the gas diffusion resistance in the catalyst layer increases as the fine particles increase. The results of this study will provide important insights into the design and fabrication of the catalyst layers in PEMFCs and could potentially lead to improvements in the efficiency of fuel cells.
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Takahashi, Sayaka, Toshio Iwataki, Tetsuro Tano, Takayuki Asakawa, Katsuyoshi Kakinuma, Kenji Miyatake e Makoto Uchida. "Performance and Durability of Membrane-Electrode Assemblies Using Non-Precious Metal Catalyst and a Hydrocarbon-Based Electrolyte for Anion Exchange Membrane Water Electrolysis". ECS Meeting Abstracts MA2023-02, n. 65 (22 dicembre 2023): 3162. http://dx.doi.org/10.1149/ma2023-02653162mtgabs.
Abstract (sommario):
Anion exchange membrane water electrolysis (AEMWE) is operated in an alkaline environment and has a similar membrane-electrode assembly (MEA) structure to that of proton exchange membrane water electrolysis (PEMWE). The use of non-noble metals as the electrocatalysts and operation at high current densities are inherently possible, so they are expected to be low-cost, high-performance candidates for next-generation water electrolysis systems. Improving the anion conductivity of the AEM and the activity of the non-precious metal catalysts is essential for the practical application of AEMWEs.1 The non-noble electrocatalysts used in the MEA in this study were Ni0.8Co0.2O2 and Ni0.8Fe0.2O,3 which have a fused-aggregate network structure, and the electrolyte was a hydrocarbon-based AEM (QPAF-4)4, all of which were developed at the University of Yamanashi. The catalyst ink for the anodes was prepared by mixing the Ni0.8Co0.2O catalyst (University of Yamanashi) with solvent (water/methanol) and QPAF-4 (IEC = 2.0 meq g-1, University of Yamanashi) binder solution. The anode ink was coated by using pulse-swirl-spray (PSS, Nordson) on the QPAF-4 membranes (IEC = 1.5 meq g-1) to make the catalyst-coated membranes (CCMs) with the anode. Catalyst inks for the cathodes was prepared by mixing Ni0.8Fe0.2O catalyst (University of Yamanashi) or Pt/CB catalyst (TEC10E50E, Tanaka Kikinzoku) with solvent (water/methanol) and QPAF-4 (IEC = 2.0 meq g-1) binder solution. The cathode ink was coated by using PSS on the gas diffusion layer (GDL, TGP-H-120, Toray) to make the gas diffusion electrodes (GDEs) for the cathodes. Ni mesh (Bekaert.co.jp) was used for the anode GDLs. The single cell (Figure 1, cell structure developed by Yokohama National University) performances were measured while supplying 1 M KOH at 80 °C to both electrodes. Figure 2 (a) shows the I-V performance of cells using Ni0.8Co0.2O for the anode and Ni0.8Fe0.2O or Pt/CB for the cathode. The electrolysis voltage observed for the cell with non-noble metal catalysts on both electrodes was higher than that for the cell with Pt/C on the cathode but was below 2 V at a current density of 1.2 A cm-2. The value of the onset electrolysis voltage was nearly the same as that of the corresponding rotating disk electrode,3 suggesting that the intrinsic performance of the cathode catalyst is being realized in the MEA. Increasing the amount of the cathodic catalyst loading scarcely affected the polarization. It is supposed that the fused-aggregate network structure of the Ni0.8Fe0.2O catalyst contributes to the favorable mass transfer. Figure 2 (b) shows the time dependence of the cell voltage of these cells. The increased loading amount improved the durability of the cathode. It is considered that the increase in the thickness of the cathode catalyst layer alleviated the damage of the GDL fibers to the membrane. These results indicate the possibility of adopting non-precious metal catalysts for both electrodes in AEMWE and thereby significantly reducing the catalyst cost. Acknowledgement This work was partially supported by NEDO of Japan through the AWE-1 project. References 1) A. Lim et al., J. Ind. Eng. Chem., 76, 410 (2019). 2) G. Shi et al., ACS Catal., 12, 14209 (2022). 3) G. Shi et al., ACS Omega, 8, 13068 (2023). 4) H. Ono et al., J. Mater. Chem. A, 5, 24804 (2017). Figure 1
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Liu, Pengcheng, Daijun Yang, Bing Li, Cunman Zhang e Pingwen Ming. "Influence of Degassing Treatment on the Ink Properties and Performance of Proton Exchange Membrane Fuel Cells". Membranes 12, n. 5 (22 maggio 2022): 541. http://dx.doi.org/10.3390/membranes12050541.
Abstract (sommario):
Degradation occurs in catalyst inks because of the catalytic oxidation of the solvent. Identification of the generation process of impurities and their effects on the properties of HSC ink and LSC ink is crucial in mitigating them. In this study, gas chromatography-mass spectrometry (GC-MS) and cyclic voltammetry (CV) showed that oxidation of NPA and EA was the primary cause of impurities such as acetic acid, aldehyde, propionic acid, propanal, 1,1-dipropoxypropane, and propyl propionate. After the degassing treatment, the degradation of the HSC ink was suppressed, and the concentrations of acetic acid, propionic acid, and propyl propionate plummeted from 0.0898 wt.%, 0.00224 wt.%, and 0.00046 wt.% to 0.0025 wt.%, 0.0126 wt.%, and 0.0003 wt.%, respectively. The smaller particle size and higher zeta potential in the degassed HSC ink indicated the higher utilization of Pt, thus leading to optimized mass transfer in the catalyst layer (CL) during working conditions. The electrochemical performance test result shows that the MEA fabricated from the degassed HSC ink had a peak power density of 0.84 W cm−2, which was 0.21 W cm−2 higher than that fabricated from the normal HSC ink. However, the introduction of propionic acid in the LSC ink caused the Marangoni flux to inhibit the coffee ring effect and promote the uniform deposition of the catalyst. The RDE tests indicated that the electrode deposited from the LSC ink with propionic acid possessed a mass activity of 84.4 mA∙mgPt−1, which was higher than the 60.5 mA∙mgPt−1 of the electrode deposited from the normal LSC ink.
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Vu, Thu Ha Thi, Minh Dang Nguyen e Anh Tuan Ngoc Mai. "Influence of Solvents on the Electroactivity of PtAl/rGO Catalyst Inks and Anode in Direct Ethanol Fuel Cell". Journal of Chemistry 2021 (27 aprile 2021): 1–15. http://dx.doi.org/10.1155/2021/6649089.
Abstract (sommario):
This paper presents research on the effects of common solvents such as n-butyl acetate, isopropanol, and ethanol on the properties and electroactivity of catalyst ink based on PtAl/rGO. The inks prepared by mixing PtAl/rGO catalyst, Nafion solution (5 wt%), and solvent were coated on carbon cloth by the spin coating method. The results obtained showed that ethanol was the most suitable solvent for the preparation of catalyst ink with a volume ratio between catalyst slurry and solvent of 1 : 1 (CI-EtOH (1/1) ink). The surface of the CI-EtOH (1/1) coated electrode was smooth, flat, and even and had no cracks due to the increase of Nafion mobility, resulting in significant improvement in the interaction between Pt particles and ionomer. Moreover, the electrochemical activity of the CI-EtOH (1/1) ink in ethanol electrooxidation reaction, in both acidic and alkaline media, has the highest value, with the forward current density, IF, reaching 1793 mA mgPt−1 and 4751 mA mgPt−1, respectively. In the application in direct ethanol fuel cell (DEFC), the CI-EtOH ink-coated anode also exhibited the highest power density in both PEM-DEFC (with a proton exchange membrane) and AEM-DEFC (with an anion exchange membrane) at 19.10 mW cm−2 and 27.07 mW cm−2, respectively.
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Chon, Gajeon, Minhee Suk, Frédéric Jaouen, Min Wook Chung e Chang Hyuck Choi. "Deactivation of Fe-N-C catalysts during catalyst ink preparation process". Catalysis Today 359 (gennaio 2021): 9–15. http://dx.doi.org/10.1016/j.cattod.2019.03.067.
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Srivastav, Harsh, Adam Z. Weber e Clayton J. Radke. "Predicting Fuel Cell Ink Aggregation". ECS Meeting Abstracts MA2022-02, n. 41 (9 ottobre 2022): 1533. http://dx.doi.org/10.1149/ma2022-02411533mtgabs.
Abstract (sommario):
Polymer-electrolyte fuel cells (PEFCs) provide multisector decarbonization solutions including in transportation, manufacturing, and long-term energy storage. They have become increasingly popular in these areas due to their high efficiency, power density, and low (or zero) emissions compared to traditional fossil-fuel dependent processes. The PEFC catalyst layer is the most complex and key part of the cell, and is critical for optimizing PEFC performance. Several studies have explored the structure/function relationships of PEFC catalyst layers, yet the physics and interactions controlling its in-situ formation remain a mystery. PEFC catalyst layers are traditionally fabricated out of a catalyst supported on a carbon nanoparticle with an ionomer, traditionally perfluorosulfonic acids (PFSAs) such as Nafion, as a binder, which stabilizes the carbon suspensions in the ink dispersion. Recent studies demonstrated the importance of pH as an experimental parameter for both comparison and characterization of such systems.1 In this talk, we explore the interactions in the colloidal inks through detailed mathematical modeling. We propose a kinetics-based model representing species aggregation with pointwise interacting spheres that vary in charge through buried side chains for predicting the aggregation behavior of Nafion and carbon in solutions under varying conditions, such as solvent, Nafion wt% and carbon wt%. To demonstrate the accuracy and robustness of the model, we compare the results against a range of pH conditions and size distributions. The insights from the model help establish design criteria and guide future ink and process conditions. Acknowledgements This study was conducted under the Million Miles Fuel Cell Truck Consortium (M2FCT) funded by the Hydrogen and Fuel Cell Technologies Office in the Energy Efficiency and Renewable Energy Office of the U.S. Department of Energy under contract DE-AC02-05CH11231. References S. A. Berlinger, B. D. McCloskey, and A. Z. Weber, J. Phys. Chem. B, 122, 7790–7796 (2018).
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Tricker, Andrew W., Julie C. Fornaciari, Jason Keonhag Lee, Nemanja Danilovic, Xiong Peng e Adam Z. Weber. "Tuning Catalyst-Ink Formulations for Blade Coating of Hydroxide-Exchange-Membrane Water Electrolyzers". ECS Meeting Abstracts MA2022-02, n. 44 (9 ottobre 2022): 1657. http://dx.doi.org/10.1149/ma2022-02441657mtgabs.
Abstract (sommario):
Clean hydrogen, produced by splitting water into H2 and O2 using renewable electricity, will play a crucial role as a renewable energy carrier and in decarbonizing industrial and hard-to-decarbonize transport sectors in the future.1 Hydroxide-exchange-membrane water electrolyzers (HEMWEs) have the potential to be more cost effective compared to the incumbent technology, proton-exchange-membrane water electrolyzers (PEMWEs) through the use of cheaper and more abundant catalysts and cell components.2 However, compared to PEMWEs, HEM systems have been studied significantly less and generally have much lower performance. Here, we systematically investigated a series of pivotal parameters that are related to catalyst inks, catalyst-layer structures, and porous-transport layer/catalyst-layer interfaces for HEMWEs. An integrated reference electrode is utilized to differentiate each individual effects on the cathode and anode when studying cell performance and durability. Catalyst-ink formulations are studied by varying ionomer-to-catalyst ratios, solid concentration, and solvent compositions. Additionally, parameters around the ink coating process are explored to study their impacts on catalyst-layer structures and provide guidance on key considerations for manufacturing robust catalyst layers. Finally, the impacts of porous-transport-layer architecture and cell configuration on the cell performance are probed. The findings elucidate critical properties and highlight urgently needed experimental practices towards high-performing HEMWEs. Acknowledgements This work was funded under the HydroGEN Consortium by the Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office, of the U. S. Department of Energy under contract number DE-AC02-05CH11231. References 1. B. Pivovar, N. Rustagi and S. Satyapal, The Electrochemical Society Interface, 27, 47 (2018). 2. K. Ayers, N. Danilovic, R. Ouimet, M. Carmo, B. Pivovar and M. Bornstein, Annual Review of Chemical and Biomolecular Engineering, 10, 219 (2019).
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Macauley, Natalia, Sichen Zhong, Yachao Zeng, Bingzhang Zhang, Gang Wu e Hui Xu. "Fabrication and Scale-up of Highly Durable Heavy Duty Fuel Cell MEAs". ECS Meeting Abstracts MA2022-01, n. 35 (7 luglio 2022): 1426. http://dx.doi.org/10.1149/ma2022-01351426mtgabs.
Abstract (sommario):
Medium and heavy-duty PEM fuel cells operate under much harsher conditions than light duty fuel cells and are expected to last 25,000 hours in the field. These systems must therefore operate successfully in the presence of impurities, starting and stopping, freezing and thawing, humidity and load cycling. Therefore, materials, components, and interfaces used in such systems need to be highly resistant to severe mechanical and chemical stress. Novel, highly active stable Pt and ordered PtCo intermetallic nanoparticles with well-controlled particle size and composition have been synthesized on a highly efficient PGM-free single metal active site rich carbon, to maximize their synergistic effects for enhanced performance and durability. These catalysts were integrated with a variety of ionomers (Aquivion, Nafion, HOPI and high O2 permeability ionomer (HOPI)) to further improve fuel cell performance and to achieve >600 mA/mgPt at 0.9 VIR-free with a mass activity loss less than 30% after 150k square wave accelerated durability cycles; and > 600 mA/cm2 (~65% efficiency) at 0.8 V, with a performance loss < 40 mV after 150K cycles (0.6 to 0.95 V). In a PEM fuel cell, the catalyst ink formulation and mixing processes control catalyst layer coating quality, electrode morphology, and the resulting fuel cell performance and durability. Catalyst ink properties are a result of complex solvent-catalyst-ionomer interactions that depend on the mixing method employed. Here, we will compare the performance and durability of electrodes made from bath sonicated inks for ultrasonic spray coating vs. ball milled inks for Meyer rod coating. Ink rheology and catalyst particle size will be used to correlate ink properties to electrode morphology and structure and ensure consistency from batch to batch, and from small lab scale to subsequent scale-up. We will evaluate and discuss the challenges that arise when transitioning from spray coating catalyst ink on a small scale, directly on a membrane, to coating more viscous inks on gas diffusion layers (GDLs), and finally developing a roll-to-roll (R2R) fabrication process. The MEA performance and durability of the novel catalyst will be evaluated under heavy duty operating conditions. Finally, the electrode performance and durability of R2R fabricated GDEs will be tested, and compared to small scale GDEs made at Giner. This work provides a comprehensive understanding of interactions between Pt, PtCo, carbon, ionomer, membrane, and GDLs and their impact on electrode structure, fuel cell performance and durability, as well as considerations for scale up to a R2R fabrication process. The attained information will be used to improve fuel cell electrode design, fabrication and scale-up. Acknowledgement: The project is financially supported by the Department of Energy’s Fuel Cell Technology Office under the Grant DE-FOA-0002360.
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Turtayeva, Zarina, Feina Xu, Jérôme Dillet, Kévin Mozet, Régis Peignier, Alain Celzard e Gaël Maranzana. "The Influence of Ink Formulation and Preparation on the Performance of Proton-Exchange Membrane Fuel Cell". Energies 16, n. 22 (10 novembre 2023): 7519. http://dx.doi.org/10.3390/en16227519.
Abstract (sommario):
The fabrication step of the catalyst layer (CL) is important to master in order to achieve good performance in fuel cells. Nevertheless, the final structure of a CL depends on many factors, such as the ink composition and preparation, as well as the order of its preparation steps. However, it is not easy for neophytes to understand the relationship between the composition of the ink with the obtained structure of the catalyst layer and its performance in fuel cells. In this work, a systemic experimental study was carried out in order to qualitatively correlate the performance of the PEMFC with the structure of the catalyst layer by playing on different parameters such as the composition and preparation of the ink and the operating conditions. All of the prepared samples were characterized by electron microscopy and profilometry, as well as by electrochemical tests at a single-cell level. The main results show that (i) the chosen ratio and ingredients result in a catalyst layer structure that can affect the PEMFC performance in different ways, and (ii) the reproducibility of the results requires particular care in the choice of catalyst and carbon support.
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Halim, El Mahdi, Lisa Pierinet, Rémi Blanchard, Maidhily Manikandan, Thi bich hue Tran, Micah Barker, Janith Kariyawasam, Fanny Tricot e Julien Durst. "Electrode Coating Process Impact on the Performance of Pt and PtCo Fuel Cell Cathode Catalysts". ECS Meeting Abstracts MA2023-02, n. 40 (22 dicembre 2023): 1983. http://dx.doi.org/10.1149/ma2023-02401983mtgabs.
Abstract (sommario):
The polymer electrolyte membrane fuel cell (PEMFC) is one of the most promising energy sources for replacing fossil fuels in vehicles, as it does not produce greenhouse gas emissions during operation. As a key player in hydrogen mobility, SYMBIO is developing and producing PEMFC systems for a large field of applications. SYMBIO masters the electrochemical core (the Membrane Electrode Assembly - MEA), the complete stack (bipolar plate, stacking and housing) and the fuel cell system (Balance of Plant, operating conditions, control-command, packaging) [1]. The widespread use of fuel cell vehicles is strongly linked to the price of the PEMFC system, in which the MEA as a high share. Decreasing the total PGM content, as well as moving to high-speed roll-to-roll production methods are important levers in the cost roadmap of MEAs. And from a performance point of view, systems for the heavy-duty market will need to show high efficiencies at low current densities (<1 A/cm2). Exploring the potential of highly active cathode catalyst is therefore mandatory for these applications. State of the art cathode catalyst layers consists in either Pt or PtCo-alloy supported on carbon material, the latter being more active for the ORR but also less resistant towards potential cycling. Regarding the ink formulation, the use of PtCo poses the challenge that Co atoms could dissolve, even if the catalyst has been previously acid leached, leading to the release of free Co2 +. These free ions will latter lower the catalytic activity and the transport of reactants (H+ and O2) to the active sites in the catalytic layer [2-3]. The manufacturing of a catalyst coated membrane (CCM) can be done with different printing processes involving a catalytic ink and a substrate. Each coating process has different constraints (ink rheological behaviour, particle size) leading to optimisation of ink recipe (solvent matrix, solid content ...). The ink must also be compatible with the substrate that can be directly an MEA component such as the membrane (direct coating) or the GDL, or a decal-carrier substrate. All these parameters lead to catalyst layer structure differences that impact the MEA performance. In this study, the impact of three coating processes, hence three solvent systems for a same catalyst, ionomer, and I/C ratio, on the MEA performance is explored for commercial Pt and PtCo catalysts. The coating processes compared are direct coating on membrane via bar coater and spray coater and non-direct coating using decal method. The inks properties including the granulometry and the viscosity of different prepared inks were characterized before coating. Ex-situ techniques (SEM-EDX, TEM, N2 adsorption/desorption) were used to figure-out the impact of the coating process on the morphology and porosity of the cathodic catalyst layer. The influence of these parameters on the electrochemical performance was studied using H2-Air polarization curves, electrochemical impedance spectroscopy and the electrochemical surface area (ECSA). It will be highlighted how important the final PEMFC performance must be understood by taking into account the used ink system and coating process, as well as the intrinsic stability of catalyst, ionomer and membrane during these stages. References [1] www.symbio.one [2] Nagappan Ramaswamy et al 2021 J. Electrochem. Soc. 168 024519 [3] Deborah J. Myers et al 2021 J. Electrochem. Soc. 168 044510
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Song, Chaojie, Ken Tsay, Elizabeth Fisher, Nate Sheibley, Nima Shaigan, Ali Malek e Khalid Fatih. "A Study on Effect of Ionomer Content on Catalyst Ink Property and PEM Water Electrolyzer Performance". ECS Meeting Abstracts MA2023-01, n. 36 (28 agosto 2023): 2110. http://dx.doi.org/10.1149/ma2023-01362110mtgabs.
Abstract (sommario):
Producing hydrogen from water electrolysis with renewable electricity is essential for a carbon-free and environment-friendly economy. Proton exchange membrane (PEM) water electrolysis has advantages over other types of water electrolysis technologies with respect to compact system, high purity H2, high current density operation, better safety and reliability etc. Catalyst coated membrane (CCM) is the core of the membrane electrode assembly (MEA) and PEM water electrolyzer [1]. The CCMs are prepared by depositing catalyst inks onto the polymer electrolyte membrane. The composition of the catalyst inks plays an important role in determining the CCM and PEMWE performance. Catalyst ink is prepared from catalyst, ionomer and solvent. Commonly used is IrOx as catalyst, Nafion solution as ionomer (binder and proton conductivity path), and a mixture of organic solvent and water as solvent. One of the key parameters determining the CCM performance is the ionomer content in the catalyst layer. A wide range of ionomer content was reported in the literature, ranging from 2 to 30wt%. Xu et al. reported an optimal value of 25 wt% ionomer content using Ru0.7Ir0.3O2 [1]. The same Nafion content was used by Su et al. with IrO2 [2]. Bernt and Gasteiger found 11.6 wt% ionomer content showed the best performance with IrO2/TiO2 [3]. Ma et al. concluded that 30 wt% ionomer content was the best using Ir black [4]. P. Holzapfel et al [5] and S. Khandavali et al [6] used 2 wt% of ionomer content in their studies with IrO2. The large variability of the ionomer content indicates that there is a need on fundamental understanding of the effect of ionomer content for PEMWE applications. Catalyst ink properties may affect the catalyst layer structure and further PEMWE performance. S. Khandavali et al. studied the rheology and microstructure of the catalyst inks [7]. However, no further steps were presented such as fabricating CCMs using the ink and testing the CCMs in PEMWE. How the ink properties affect the catalyst layer structure, and further the PEMWE performance are not studied to our knowledge. In this work, a study on effect of ionomer content on catalyst ink property and further PEMWE performance is presented. In this work, catalyst ink was prepared from a mixture of isopropanol and water (1:1), Nafion solution, and IrO2. Inks with Nafion concentrations ranging from 1.0 wt. % to 20 wt. % were investigated. Ink properties such as viscosity, Zeta-potential and average particle size were studied. Properties of CCMs developed from the inks by directly coating the catalyst ink on Nafion membrane using ultrasonic spray were also investigated. The CCMs prepared from inks with 5.0, 7.0, 8.5 and 10% Nafion were tested in PEM water electrolyzer single cell at 80oC and ambient pressure. The CCM with the 7.0% Nafion shows the highest performance, while the 5.0% Nafion shows the lowest. The 8.5 and 10% Nafion CCMs show slightly lower performance than the 7.0%. The PEMWE was diagnosed with AC impedance. Fig. 1 presents the EIS spectra of the four CCMs in PEMWE obtained at 50 mA.cm-2. It can be seen that other than the CCM with 5.0% Nafion, all other 3 CCMs showed similar spectra. This is in agreement with the polarization curves. Impedance data fitting using the modified Randles equivalent circuit (solid lines in Fig. 1) shows that the 5.0% Nafion demonstrated the highest anode charge transfer resistance (oxygen evolution reaction (OER)) and the 7.0% shows the lowest value. Correlation of the ink properties with the PEMWE performance will be presented. References Xu, K. Scott, Int. J. Hydrogen Energy, 35 (2010) 12029 – 12037 Su, B. J. Bladergroen, V. Linkov, S. Pasupathi, S. Ji, Int. J. Hydrogen Energy, 36 (2011) 1615081 – 15088 Bernt, H. Gasteiger, J. Electrochem. Soc., 163 (11) (2016) F3179 – F3189 Ma, S. Sui, Y. Zhai, Int. J. Hydrogen Energy, 34 (2009) 678 – 684 Holzapfel, M. Bühler, C. V. Pham, F. Hegge, T. Böhm, D. McLaughlin, M. Breitwieser, S. Thiele, Electrochem. Commun. 110 (2020) 106640 Buhler, P. Holzapfel, D. McLaughlin, S. Thiele, J. Electrochem. Soc., 166 (14) (2019) F1070 – F1078 Khandavali, J. H. Park, N. N. Nariuki, S. F. Zaccarine, S. Pylypenko, D. J. Myers, M. Ulsh, S. A. Mauger, ACS Appl. Mater. Interfaces, 11 (2019) 45068 – 45079 Figure 1
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Dixit, Marm B., Brice A. Harkey, Fengyu Shen e Kelsey B. Hatzell. "Catalyst Layer Ink Interactions That Affect Coatability". Journal of The Electrochemical Society 165, n. 5 (2018): F264—F271. http://dx.doi.org/10.1149/2.0191805jes.
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Sun, Yujiao, Shaoyi Xu e Hui Li. "Incorporation of PEDOT:PSS to Reduce Iridium Loading at Anode Catalyst Layer for Proton Exchange Membrane Water Electrolysis". ECS Meeting Abstracts MA2023-02, n. 65 (22 dicembre 2023): 3102. http://dx.doi.org/10.1149/ma2023-02653102mtgabs.
Abstract (sommario):
Proton exchange membrane water electrolysis (PEMWE) is one of the most promising technologies to produce green hydrogen with high efficiency. However, its commercialization is hindered by the large usage of expensive iridium as anode electrocatalyst [1-3] . Incorporation of cheap conductive materials into the catalyst ink, e.g., titanium powder [4], is a straightforward and efficient method to reduce noble metal loading of membrane electrode assembly (MEA). In this study, we aimed to use a conductive polymer PEDOT:PSS to build the low Ir loading catalyst layer for PEMWE. The MEAs at 0.3 mgIr cm-2 loading were fabricated with different PEDOT:PSS contents. In practice, the dispersion of IrO2 particles is difficult in catalyst ink, leading to the formation of big IrO2 agglomerates. We found that the zeta potential of the anode catalyst ink gained obvious enhancement after the addition of PEDOT:PSS. This indicated that PEDOT:PSS as dispersant could increase the stability of the catalyst ink. The morphology of anode catalyst layers was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface and cross-sectional images of morphology exhibited small IrO2 particles and porous structure in the catalyst layer with the addition of PEDOT:PSS, which would contribute to the water/gas movement in triple-phase boundaries. Electrochemical measurements such as polarization curves, electrochemical impedance spectroscopy (EIS), cyclic voltammogram (CV) and durability tests were conducted in a PEMWE single cell. The MEA using PEDOT:PSS as binder displayed better electrochemical performance (3.4 A cm-2@2.0 V) than other references with Nafion only (2.4 A cm-2@2.0 V). Moreover, the addition of PEDOT:PSS improved the high-frequency resistance due to its excellent electronic conductivity. In consideration of the conductive binder and dispersant effect of PEDOT:PSS, future research will focus on reducing Ir loading below 0.1 mg cm-2 through designing novel structure of anode catalyst layer with PEDOT:PSS. Keywords: PEM water electrolysis, low iridium loading, PEDOT:PSS References: [1] Carmo, M., et al., A comprehensive review on PEM water electrolysis. International Journal of Hydrogen Energy, 2013. 38(12): p. 4901-4934. [2] Chen, Y., et al., Key Components and Design Strategy for a Proton Exchange Membrane Water Electrolyzer. Small Structures, 2022. [3] Shiva Kumar, S. and V. Himabindu, Hydrogen production by PEM water electrolysis – A review. Materials Science for Energy Technologies, 2019. 2(3): p. 442-454. [4] Rozain, C., et al., Influence of iridium oxide loadings on the performance of PEM water electrolysis cells: Part II – Advanced oxygen electrodes. Applied Catalysis B: Environmental, 2016. 182: p. 123-131. Fig 1. Polarization curves for MEAs. Anode and cathode catalyst loading were 0.3 mgIr cm-2 and 0.3 mgPt cm-2, respectively; Nafion 115 membrane and 80℃. Figure 1
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Alekseenko, Anastasia, Sergey Belenov, Dmitriy Mauer, Elizaveta Moguchikh, Irina Falina, Julia Bayan, Ilya Pankov, Danil Alekseenko e Vladimir Guterman. "Activity of Platinum-Based Cathode Electrocatalysts in Oxygen Redaction for Proton-Exchange Membrane Fuel Cells: Influence of the Ionomer Content". Inorganics 12, n. 1 (2 gennaio 2024): 23. http://dx.doi.org/10.3390/inorganics12010023.
Abstract (sommario):
Studying the ORR activity of platinum-based electrocatalysts is an urgent task in the development of materials for proton-exchange membrane fuel cells. The catalytic ink composition and the formation technique of a thin layer at the RDE play a significant role in studying ORR activity. The use of a polymer ionomer in the catalytic ink provides viscosity as well as proton conductivity. Nafion is widely used as an ionomer for research both at the RDE and in the MEA. The search for ionomers is a priority task in the development of the MEA components to replace Nafion. The study also considers the possibility of using the LF4-SK polymer as an alternative ionomer. The comparative results on the composition and techniques of applying the catalytic layer using LF4-SK and Nafion ionomers are presented, and the influence of the catalytic ink composition on the electrochemical characteristics of commercial platinum–carbon catalysts and a highly efficient platinum catalyst based on an N-doped carbon support is assessed.
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Kluender, Edward J., James L. Hedrick, Keith A. Brown, Rahul Rao, Brian Meckes, Jingshan S. Du, Liane M. Moreau, Benji Maruyama e Chad A. Mirkin. "Catalyst discovery through megalibraries of nanomaterials". Proceedings of the National Academy of Sciences 116, n. 1 (17 dicembre 2018): 40–45. http://dx.doi.org/10.1073/pnas.1815358116.
Abstract (sommario):
The nanomaterial landscape is so vast that a high-throughput combinatorial approach is required to understand structure–function relationships. To address this challenge, an approach for the synthesis and screening of megalibraries of unique nanoscale features (>10,000,000) with tailorable location, size, and composition has been developed. Polymer pen lithography, a parallel lithographic technique, is combined with an ink spray-coating method to create pen arrays, where each pen has a different but deliberately chosen quantity and composition of ink. With this technique, gradients of Au-Cu bimetallic nanoparticles have been synthesized and then screened for activity by in situ Raman spectroscopy with respect to single-walled carbon nanotube (SWNT) growth. Au3Cu, a composition not previously known to catalyze SWNT growth, has been identified as the most active composition.
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Macauley, Natalia, Sichen Zhong, Shuo Ding, Yachao Zeng, Bingzhang Zhang e Gang Wu. "Fabrication and Scale-up of Highly Durable Heavy Duty Fuel Cell MEAs". ECS Meeting Abstracts MA2023-01, n. 38 (28 agosto 2023): 2211. http://dx.doi.org/10.1149/ma2023-01382211mtgabs.
Abstract (sommario):
Medium and heavy-duty PEM fuel cells operate under much harsher conditions than light duty fuel cells and are expected to last 25,000-30,000 hours in the field. These systems must operate successfully in the presence of impurities, starting and stopping, freezing and thawing, humidity and load cycling. Therefore, materials, components, and interfaces used in such systems must be highly resistant to severe mechanical and chemical stress. Novel, highly active stable Pt and ordered PtCo intermetallic nanoparticles with well-controlled particle size and composition have been synthesized on a highly efficient PGM-free single metal active site rich carbon, to maximize their synergistic effects for enhanced performance and durability. Integrating these catalysts integrated with high O2 permeability ionomer (HOPI) in membrane electrode assemblies (MEAs) improved their fuel cell performance and durability, allowing the MEAs to achieve >600 mA/mgPt at 0.9 VIR-free with a mass activity loss < 30% after 150k square wave accelerated stress test (AST) cycles; and > 600 mA/cm2 (~65% efficiency) at 0.8 V, with a performance loss < 40 mV after 150K AST cycles. In a PEM fuel cell, the catalyst ink formulation and mixing processes control catalyst layer coating quality, electrode morphology, and the resulting fuel cell performance and durability. Catalyst ink properties are a result of complex solvent-catalyst-ionomer interactions that depend on the mixing method employed. Here, we compare the performance and durability of electrodes made from bath sonicated inks for ultrasonic spray coating before and after the catalyst scale up. Ink rheology and catalyst particle size are used to correlate ink properties to electrode morphology and structure and ensure consistency from batch to batch, and from small lab scale to subsequent scale-up. We evaluate and discuss the challenges that arise when transitioning from spray coating catalyst ink on a small scale, directly on a membrane, to coating more viscous inks on gas diffusion layers (GDLs), made via Mayer rod coating of ball milled inks, in anticipation of developing a roll-to-roll (R2R) fabrication process. The MEA performance and durability of the novel catalyst was also evaluated under heavy duty operating conditions using M2FCT’s AST, i.e., in H2/Air, 90 ⁰C, and 50% RH. This work provides a comprehensive understanding of interactions between Pt, PtCo, carbon, ionomer, membrane, and GDLs and their impact on electrode structure, fuel cell performance and durability, as well as considerations for scale up to a R2R fabrication process. The attained information will be used to improve fuel cell electrode design, fabrication and scale-up. Acknowledgement: The project is financially supported by the Department of Energy’s Fuel Cell Technology Office under the Grant DE-SC0021671. Figure 1. (a) Comparison of H2-air fuel cell performance of HOPI-based CCMs prepared with different volume ratios of H2O to n-propanol (nPA). (b) Dependence of fuel cell performance at 0.8 and 0.7 V of the CCMs prepared with different volume ratios of H2O to nPA. (c) MEA performance of the best performing Pt (40 wt. %)/Mn-N-C MEA under various relative humidity. (d) The high-frequency resistance (HFR) of HOPI-based CCMs prepared with a volume ratio of 2:1. All of the tests were performed with a 5 cm2 differential cell with 14 parallel channels. The cell temperature was 80 ⁰C, the flow rates for H2 and air are 500 and 2000 sccm, and the backpressure is 250 kPaabs. The Pt loading in the anode and cathode are 0.1 and 0.2 mgPt/cm2, respectively. Figure 1
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Stoll, Jonas, Erik Kjeang e Philip Huynh. "Effects of Wet Film Application Parameters on the Structure and Performance of Fuel Cell Catalyst Layers Prepared Using Scalable Methods". ECS Meeting Abstracts MA2022-02, n. 40 (9 ottobre 2022): 1481. http://dx.doi.org/10.1149/ma2022-02401481mtgabs.
Abstract (sommario):
The use of high-volume manufacturing processes for polymer electrolyte fuel cells is obligatory to bring the manufacturing cost closer to 80USD/kW fuel cell system cost target for long-Haul Trucks [1] and thereby make this technology an economical competitor in the carbon neutral transportation sector. For the membrane electrode assembly, thin film roll good materials are therefore the norm in the industry. On the lab scale however, catalyst layers and catalyst coated membranes (CCMs) are commonly prepared with low throughput multi-sub-layer coating application techniques, such as ultrasonic spray coating. Overall, each catalyst sub-layer is dried before the next sub-layer is applied via another spraying pass, until the desired catalyst loading and therewith the overall catalyst layer is created. This multi-sub-layer coating approach is therefore time consuming. However, to simulate high volume manufacturing at the lab scale, direct layer coating techniques such as film applicator or Mayer bar coating can be utilized. These coating methods are designed to form a one pass final catalyst wet film thickness, similar to what transpires in a continuous high throughput roll to roll (R-2-R) manufacturing process. As opposed to the multi-layer coating techniques, the entire wet thickness of the catalyst layer is dried in one step, which allows greater throughput, but also influences the catalyst layer formation. Because when a catalyst wet film dries, there are forces related to evaporation, diffusion, and sedimentation which influence the distribution of materials and the ultimate catalyst layer structure [2]. Furthermore, catalyst inks used for Mayer-rod, film applicator, and R-2-R coating methods generally have higher solids content than the inks used in spray coating. With the one pass techniques, CCMs are typically fabricated by coating catalyst ink on a decal film, such as polytetrafluoroethylene (PTFE), followed by a hot lamination process, such as decal transfer, of the catalyst layer to the membrane [3]. Due to the interaction of the catalyst ink with the coating substrate and drying process, there are many factors that may influence the quality of the catalyst layer obtained with direct layer coating, considering both ink formulation and coating parameters. To understand the interaction of these influences, we investigate the effects of wet film application parameters on the structure and performance of fuel cell catalyst layers, prepared using scalable methods. The same drying technique of hot air drying is used to obtain a closer representation of the direct layer R-2-R process. In more detail, we are determining the influence of the following factors on the catalyst layer formation, when coated on a PTFE substrate: drying temperature, ionomer-to-carbon support ratio, ink water-to-alcohol ratio, and wet film thickness for each of the two-lab scale direct layer coating methods. Finally, we will discuss the influence of these factors on the catalyst structure via microscopy. As well as performance and electrochemical analysis data, of selected catalyst layers, after being decal transferred onto a membrane and tested. Figure 1 shows an example of the variance of dried catalyst layers coated via two direct coating methods on PTFE substrates from the alterations of Ink Water-to-Alcohol (2-Propanol, 1-Propanol, Ethanol) ratio and coating wet thicknesses. As can be seen the dried catalyst layer structure vary depending on the Ink Water-to-Alcohol ratio, wet thickness and application method used. Acknowledgments This research was supported by the Simon Fraser University Community Trust Endowment Fund, Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation, British Columbia Knowledge Development Fund, Western Economic Diversification Canada, and Canada Research Chairs. Reference [1] Menezes, Mark W., et al. “"US Department of Energy Hydrogen Program Plan” https://www.hydrogen.energy.gov/roadmaps_vision.html (2020) [2] C.M. Cardinal, Y.D. Jung, K.H. Ahn, L.F. Francis, Drying regime maps for particulate coatings, AIChE J. 56 (2010) 2769–2780, https://doi.org/10.1002/ aic.12190. [3] Wei, Zhaoxu, et al., High performance polymer electrolyte membrane fuel cells (PEMFCs) with gradient Pt nanowire cathodes prepared by decal transfer method. International Journal of Hydrogen Energy 40.7 (2015): 3068-3074. Figure 1
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Shibayama, Mitsuhiro, Takuro Matsunaga, Takumi Kusano, Kazuki Amemiya, Noriyuki Kobayashi e Toshihiko Yoshida. "SANS studies on catalyst ink of fuel cell". Journal of Applied Polymer Science 131, n. 3 (31 agosto 2013): n/a. http://dx.doi.org/10.1002/app.39842.
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Yoshino, Shuhei, Masashi Harada, Naoki Hasegawa e Ryosuke Jinnouchi. "Design of Carbon Aggregation Structure in Polymer Electrolyte Fuel Cell Catalyst Ink by Solvent Hydrophilicity". ECS Meeting Abstracts MA2023-02, n. 38 (22 dicembre 2023): 1815. http://dx.doi.org/10.1149/ma2023-02381815mtgabs.
Abstract (sommario):
Controlling the porous structure of the cathode catalyst layer in a polymer electrolyte fuel cell is essential to reduce the reaction and mass transport resistance of the oxygen reduction reaction. As the catalyst layer is a coating of a catalyst ink, the aggregation structure of platinum-supported carbon (Pt/C) and ionomer in ink is a key property for achieving the optimal catalyst layer.1 Previous studies reported that the weight fraction of water in solvents could control aggregation structure in ink.2-4 For example, Kumano et al.2 reported that increasing the water ratio to 1-propanol enhances the ionomer adsorption on Pt/C (Γ) and dispersion of Pt/C, causing the lowering of the viscosity of the inks. Based on the results, they speculated that water repels ionomers and promotes their adsorption on Pt/C particles. They further speculated that the ionomers adsorbed on the Pt/C particles induce repulsive interactions between Pt/C particles via electrostatic repulsive interactions among sulfonate groups of adsorber ionomers. By the enhanced repulsive interactions, Pt/C particles are dispersed, and viscosity decreases. The discussion in the previous study likely indicates that the hydrophilicity of the solvent is an essential factor controlling the aggregation structure of catalyst ink. Here, we verify this hypothesis. As a universal indicator of the hydrophilicity, we adopt the hydrogen-bond term HSP-δH of the Hansen solubility parameters. We examined how HSP-δH is correlated to the ionomer adsorption ratio to Pt/C (Γ), viscoelasticity of ink, and structural properties of ink measured by ultra-small angle X-ray scattering (USAXS). The catalyst inks were prepared by mixing Pt/C (TEC10V30E, TKK), Nafion 20 wt% solution (DE2020, Chemours), ultrapure water, and three different alcohols [ethanol (EtOH), 1-propanol (PrOH) and diacetone alcohol (DAA)]. The water weight fraction in the solvents was set to 25 - 85 wt%. Γ is plotted as a function of HSP-δH in Fig. 1. Regardless of the alcohol species, Γ increases with increasing HSP-δH. The trend is consistent with the previously reported trend observed in the mixtures of water and 1-propanol. Figures 2 (a) and (b) show the equilibrium storage modulus G’0 obtained by the rheometer and the fractal dimension D 2 of agglomerates of Pt/C particles in ink as functions of Γ. Here, D 2 is determined by fitting the unified model5 to the USAXS spectrum obtained by the synchrotron radiation (Spring-8, Japan). Both decreases with the increase of Γ. The lowering of D 2 indicates that the agglomerates of Pt/C particles are dispersed and turn to less-structured particles, as schematically shown in Fig. 2 (c). By the dispersion, G’0 decreases. Accordingly, the hydrophilicity, indeed, promotes the ionomer adsorption, and the adsorption induces the dispersion. The hydrophilicity is a key factor controlling the structure and rheology of the catalyst ink, and HSP-δH is a universal descriptor of hydrophilicity. Reference K. B. Hatzell, M. B. Dixit, S. A. Berlinger, and A. Z. Weber, J. Mater. Chem. A, 5 (39), 20527-20533 (2017). N. Kumano, K. Kudo, Y. Akimoto, M. Ishii, and H. Nakamura, Carbon, 169 429-439 (2020). S. Takahashi, T. Mashio, N. Horibe, K. Akizuki, and A. Ohma, ChemElectroChem, 2 (10), 1560-1567 (2015). T. Van Cleve, S. Khandavalli, A. Chowdhury, S. Medina, S. Pylypenko, M. Wang, K. L. More, N. Kariuki, D. J. Myers, A. Z. Weber, S. A. Mauger, M. Ulsh, and K. C. Neyerlin, ACS Appl Mater Interfaces, 11 (50), 46953-46964 (2019). G. Beaucage, H. K. Kammler, and S. E. Pratsinis, J. Appl. Crystallogr., 37 (4), 523-535 (2004). Figure captions Figure 1 Dependence of the ionomer adsorption ratio Γ on the HSP-δH of the catalyst ink solvent. Figure 2 (a) Γ dependence of the equilibrium storage modulus G’0 of the catalyst inks. G’0 is plotted on a logarithmic scale. G’0 values of inks that are not measurable due to being less than the measurable lower limit are conventionally described as 0. (b) Γ dependence of the mass fractal D 2 of Pt/C aggregates in the inks. (c) Schematic illustration of the aggregation structure of Pt/C in the solvents. Figure 1
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Taning, Ahmad Zulfikri, Seonho Lee, Seunghee Woo, Seok-Hee Park, Byungchan Bae e Sung-Dae Yim. "Characterization of Solvent-Dependent Ink Structure and Catalyst Layer Morphology Based on Ink Sedimentation Dynamics and Catalyst-Ionomer Cast Films". Journal of The Electrochemical Society 168, n. 10 (1 ottobre 2021): 104506. http://dx.doi.org/10.1149/1945-7111/ac2c13.
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Uemoto, Naoki, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata e Satoshi Kaneco. "Electrochemical Carbon Dioxide Reduction in Methanol at Cu and Cu2O-Deposited Carbon Black Electrodes". ChemEngineering 3, n. 1 (8 febbraio 2019): 15. http://dx.doi.org/10.3390/chemengineering3010015.
Abstract (sommario):
The electrochemical reduction of carbon dioxide in methanol was investigated with Cu and Cu2O-supported carbon black (Vulcan XC-72) nanoparticle electrodes. Herein, Cu or a Cu2O-deposited carbon black catalyst has been synthesized by the reduction method for a Cu ion, and the drop-casting method was applied for the fabrication of a modified carbon black electrode. A catalyst ink solution was fabricated by dispersing the catalyst particles, and the catalyst ink was added onto the carbon plate. The pH of suspension was effective for controlling the Cu species for the metallic copper and the Cu2O species deposited on the carbon black. Without the deposition of Cu, only CO and methyl formate were produced in the electrochemical CO2 reduction, and the production of hydrocarbons could be scarcely observed. In contrast, hydrocarbons were formed by using Cu or Cu2O-deposited carbon black electrodes. The maximum Faraday efficiency of hydrocarbons was 40.3% (26.9% of methane and 13.4% of ethylene) at −1.9 V on the Cu2O-deposited carbon black catalyst. On the contrary, hydrogen evolution could be depressed to 34.7% under the condition.
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Jankovic, Jasna, Maryam Ahmadi, Mariah Batool, Linda Ney, Irene Franzetti, Jeronimo Horstmann, Sunilkumar Khandavalli et al. "(Invited) Overall Research on Electrode Coating Processes (OREO) - the Role of Imaging and Spectroscopy in Scale-up Fabrication of Low Temperature Water Electrolyzers". ECS Meeting Abstracts MA2023-01, n. 36 (28 agosto 2023): 1981. http://dx.doi.org/10.1149/ma2023-01361981mtgabs.
Abstract (sommario):
With the recent trends in hydrogen technologies, scale-up fabrication of membrane electrode assemblies (MEAs) for the electrochemical systems such as fuel cells and electrolyzers is gaining significant attention. Companies and researchers are focusing on diverse large-scale electrode fabrication processes, such as roll-to-roll and screen-printing. However, optimizing such processes is not trivial, and a number of parameters, including but not limited to catalyst type, solvent, ink mixing, electrode coating and drying, play a role in the quality of the final product. Correlations between the fabrication parameters and resulting electrode microstructure, properties and performance are important to understand, in order to better control the processes. Imaging and spectroscopy techniques play an important role in this understanding, starting from catalysts, inks and all the way to the electrodes. Information about catalyst distribution, composition, and surface chemistry can be correlated to ink characteristics, and finally to electrode structure, component distribution and properties, and their effect on MEA performance can be investigated. In this talk, a collaborative work between four institutions, University of Connecticut, Colorado School of Mines, National Renewable Energy Lab and Fraunhofer ISE, within a project on Overall Research on Electrode Coating Processes (OREO), is discussed, with the focus on low temperature water electrolyzers scale-up fabrication and characterization. The talk will especially focus on the role of advanced microcopy and spectroscopy in the characterization of catalyst powders, inks and electrodes.
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Zhang, Qing, Li Li Huang, Mei Ye Wu e Xiao Zhang Yu. "Primary Study on the Improvement and Application of Formulation Optimization of 2116# Rosin Modified Phenolic Resin". Key Engineering Materials 837 (aprile 2020): 168–73. http://dx.doi.org/10.4028/www.scientific.net/kem.837.168.
Abstract (sommario):
2116# Rosin Modified Phenolic Resin is synthesized by means of one-step process taking calcium hydroxide as catalyst and Rosin, Bisphenol A, solid formaldehyde and glycerol as main raw materials. The formulation and process are improved and characterized. The result shows that it satisfies technical performance indicators. And, it is preliminarily applied to ink. This resin is expected to be applied to printing ink and coating industry.
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Ronovský, Michal, Mila Myllymäki, Shlomi Polani, Olivia Dunseath, Peter Kúš, Lujin Pan, Malte Klingenhof et al. "A Life-Cycle of Ni in Proton Exchange Membrane Fuel Cells". ECS Meeting Abstracts MA2023-01, n. 38 (28 agosto 2023): 2277. http://dx.doi.org/10.1149/ma2023-01382277mtgabs.
Abstract (sommario):
The usage of Proton Exchange Membrane Fuel Cells (PEMFCs) in the automotive industry is currently limited by the price, performance, and durability of a platinum catalyst. Alloying with nickel provides lower cost and enhances activity. However, the membrane electrode assembly (MEA) performance is, in practice, much lower than expected from liquid laboratory experiments on the catalyst layer. One of the identified issues is Ni leaching from nanoparticles (NPs) and subsequent Ni poisoning of the Nafion membrane. Here, we use Wide-Angle X-ray Scattering (WAXS) and X-ray Absorption Near-Edge Structure (XANES) to follow Ni dissolution from the catalyst layer and its movement in the MEA. We shine (synchrotron) light on the full life cycle of Ni, starting from (i) characterization of the catalyst powder, followed by (ii) the changes in catalyst composition during the ink-making process and (iii) membrane coating and finishing with (iv) NP characterization and Ni tracking during the operation of MEAs. Proper incorporation of PtNi catalyst requires modification of all the aforementioned steps that are otherwise well optimized for pure Pt catalyst. It is even more critical for shape-controlled octahedra (oh) PtNi NPs as their activity is closely related to their structure [1]. Highly active oh-PtNi NPs are usually made from precursors such as Nickel(II) bis(acetylacetonate). Using EDX, we find precursor residues in catalyst powders that dissolve upon further processing and add to membrane poisoning. We conclude that we need to develop a cleaning protocol that would remove all Ni residue while retaining the nanoparticle shape. During ink-making, high ionomer concentrations and elevated temperatures promote Ni dissolution from the catalyst, which can, in turn, poison the membrane even before the MEA is put in use. With the WAXS technique, we track the dissolution during ink-making and MEA operation by following changes in lattice parameter, showing the dynamics and the extent of Ni dissolution in each step of aging. Furthermore, we use angle-resolved XANES to track the movement of dissolved Ni. We show that Ni ions are getting reduced back to metallic form within the MEA, likely due to hydrogen crossover. The presence of such a metal band in the membrane blocks proton conductivity and decreases performance [2]. That is why it is crucial to set manufacturing and operational boundaries to prevent dissolution. For this reason, we follow WAXS total scattering intensity during oxidation and reduction cycles to understand the Ni dissolution dynamics during operation. We find that limiting both upper and lower potential cycling limits greatly reduces the redox extent and subsequent dissolution. It is, therefore, possible to find and understand the trade-off between high power density and dissolution in operational cells. Even though this work looks at the Ni life cycle, the presented techniques and conclusions are transferable to all multimetallic high-performance PEMFC catalysts. References: [1] Shlomi Polani et al. ACS Appl. Mater. Interfaces 2022, 14, 26, 29690–29702 [2] Wu Bi et al. Electrochem. Solid-State Lett. 2007 10 B101 Figure 1
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Miskan, Madihah, Takuya Tsujiguchi, Akio Kodama e Yugo Osaka. "(Digital Presentation) Power-Generation and Mass-Transport Characteristics of Direct Formic Acid Fuel Cell Using Pore-Designed Anode Electrode". ECS Meeting Abstracts MA2022-01, n. 35 (7 luglio 2022): 1476. http://dx.doi.org/10.1149/ma2022-01351476mtgabs.
Abstract (sommario):
Controlling of mass transport in the anode catalyst layer has become one of the major challenges in Direct Formic Acid Fuel Cells (DFAFCs) owing to the poor formic acid transport and crossover. This study is aim to introduce the microfiber-pores designed anode catalyst layers by mean to improve the mass transport limitation and eventually improving the performance of DFAFCs. Polystyrene fibers (PSFs) were fabricated with different diameter by electrospinning prior to control their length by ultrasonic homogenization. Different amount of PSF as a pore forming agent were then added to the catalyst ink before catalyst coated membrane (CCM) were made by spraying the catalyst ink on the membrane. The CCM were then soaked in ethyl acetate solution to remove the PSF in order to improve the porous structure of anode catalyst layer. Different diameter and amount of PSFs exhibited different pore properties of the catalyst layer and its effect on the mass transport and the performance of DFAFC were then investigated. From the results, the microfiber-pores designed anode catalyst layers showed better performance remarkably at the higher current density region as compared to the conventional anode catalyst layer. Moreover, it was also found that there were optimum diameter and amount of PSF used for the highest performance of DFAFC. This could be attributed to the existence of the microfiber-pores have provide larger active catalyst region which accelerate the fuel transport and the CO2 emission in anode catalyst layer. Thus, these results indicate that the introduction of the microfiber-pores on the anode catalyst layer is a promising approach in order to improve the mass transport resistance, leading to enhance the DFAFCs performance.
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Liu, Gaoyang, Shanlong Peng, Faguo Hou, Xindong Wang e Baizeng Fang. "Preparation and Performance Study of the Anodic Catalyst Layer via Doctor Blade Coating for PEM Water Electrolysis". Membranes 13, n. 1 (24 dicembre 2022): 24. http://dx.doi.org/10.3390/membranes13010024.
Abstract (sommario):
The membrane electrode assembly (MEA) is the core component of proton exchange membrane (PEM) water electrolysis cell, which provides a place for water decomposition to generate hydrogen and oxygen. The microstructure, thickness, IrO2 loading as well as the uniformity and quality of the anodic catalyst layer (ACL) have great influence on the performance of PEM water electrolysis cell. Aiming at providing an effective and low-cost fabrication method for MEA, the purpose of this work is to optimize the catalyst ink formulation and achieve the ink properties required to form an adherent and continuous layer with doctor blade coating method. The ink formulation (e.g., isopropanol/H2O of solvents and solids content) were adjusted, and the doctor blade thickness was optimized. The porous structure and the thickness of the doctor blade coating ACL were further confirmed with the in-plane and the cross-sectional SEM analyses. Finally, the effect of the ink formulation and the doctor blade thickness of the ACL on the cell performance were characterized in a PEM electrolyzer under ambient pressure at 80 °C. Overall, the optimized doctor blade coating ACL showed comparable performance to that prepared with the spraying method. It is proved that the doctor blade coating is capable of high-uniformity coating.
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Ito, Seigo, e Yuuki Mikami. "Porous carbon layers for counter electrodes in dye-sensitized solar cells: Recent advances and a new screen-printing method". Pure and Applied Chemistry 83, n. 11 (24 agosto 2011): 2089–106. http://dx.doi.org/10.1351/pac-con-11-04-03.
Abstract (sommario):
We review the recent literature on carbon catalyst layers for dye-sensitized solar cells (DSCs), and then report an improved fabrication method for screen-printed carbon counter electrodes. The carbon-printing ink was prepared by mixing carbon black, TiO2 nanoparticles, α-terpineol, and ethyl cellulose using a mortar, an ultrasonic homogenizer, and a rotary evaporator. Scanning electron microscopy (SEM) showed that the resulting screen-printed carbon layers were flatter and smoother at nano- and micro-scales than a carbon layer prepared using water-based ink. The photovoltaic performance of the screen-printed catalyst layers was similar to the photoenergy conversion of platinum counter electrodes. The highest cell efficiency with a carbon counter electrode was 7.11 % at a light intensity of 100 mW cm-2.
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Saito, Yuki, Kayoung Park, Magnus So e Gen Inoue. "(Digital Presentation) Simulation of Agglomeration in Polymer Electrolyte Fuel Cell Catalyst Inks". ECS Meeting Abstracts MA2022-02, n. 39 (9 ottobre 2022): 1393. http://dx.doi.org/10.1149/ma2022-02391393mtgabs.
Abstract (sommario):
Polymer electrolyte fuel cells (PEFCs) are expected to use as a power source for new generation automobiles, especially heavy-duty vehicles because of their low environmental affection. To be widely spread, it is essential to increase their power output and reduce the cost of catalyst platinum. Since oxygen reduction reaction (ORR) at the cathode is the dominant reaction, there is a need to improve the oxygen transport and proton conductivity. In recent years, porous carbon has been studied and it has been found its high activity and durability. However, the catalyst layer made of porous carbon gets a lower voltage than that made of non-porous carbon in the high current density area. This output reduction results from high oxygen transport resistance, but it is unclear how the porous structure influences the performance. So in this study, we assumed the following relation. Firstly, the difference in voltage at a high current density between carbons results in oxygen transport properties. Secondly, their properties depend on an effective oxygen diffusion coefficient, which is determined by the porous structure in the catalyst layer. And finally, the factor that attributes the catalyst layer structure is the size of the agglomerate in the catalyst ink because the catalyst layer is fabricated by the wet process. Therefore, we focused on the particle agglomeration process in catalyst ink and calculated the agglomerate behavior under various ink conditions using a numerical model. The differences in the agglomeration and its factors were also examined for carbon with different internal pores. A three-dimensional discrete element method (DEM) was used to calculate agglomeration. Initially, aggregates, the smallest unit of carbon black, were placed randomly in the cubic region. In this simulation, aggregates were regarded as spheres. The distance of movement was determined by solving the equation of motion. For each particle, the fluid drag, Brownian motion, and particle interactions were considered. The particle-particle interaction included the forces based on DLVO theory [1] and the ionomer effect. Several studies show that ionomer adsorbed on the carbon aggregates improves their stability. So it was assumed that the ionomer effect was the repulsive force and modeled using the same equation as for the EDL force. The dielectric constant dependence of this effect was used in the function previously reported by Magnus et al. [2]. The carbon particles assumed here were non-porous (Vulcan) and porous (Ketjen), and were coated with Pt particles. The initial average diameter of the aggregates was 300 nm. Hamaker coefficient was expressed as an average of the physical properties of platinum and carbon black, which was weighted by the percentage of platinum loaded on the surface of the carbon particles. The solvent was a mixture of 1-propanol (NPA) and water, and the dielectric constant of the ink was expressed as a weighted average of the composition ratio of water and NPA. The simulation was conducted under various water/alcohol ratios and ionomer/carbon ratios (I/C). From this model, it was confirmed that the carbon internal pores affect the size of the agglomerate in the catalyst ink. References [1] B. Derjaguin et al., Prog. Surf. Sci., 43 30 (1993). [2] M. So et al., Int. J. Hydrog. Energy, 44 28984 (2019).
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Liu, Jiawei, Austin Plymill, Scott Blackburn, Andrew M. Park e Shawn Litster. "Studying Crack Formation in Catalyst Layer Films for Proton Exchange Membrane Fuel Cells". ECS Meeting Abstracts MA2023-01, n. 38 (28 agosto 2023): 2219. http://dx.doi.org/10.1149/ma2023-01382219mtgabs.
Abstract (sommario):
The performance and durability of proton exchange membrane fuel cells (PEMFCs) can be affected by cracks formed in catalyst layers (CLs). While previous research has shown that CLs prepared with pre-commercial high oxygen permeability ionomer (HOPI) are more efficient and durable, they can lead to significantly more cracking features than CLs prepared with traditional perfluorosulfonic acid (PFSA) ionomer. Therefore, it is important to reduce cracking to further improve cathode performance, durability, and film quality. With this goal in mind, we analyzed ink drying and crack formation during the wet-film coating process via imaging with an optical microscope fixed above a film applicator. Transient quantitative crack growth studies were performed to evaluate the dynamic nature of the process. Alongside that, the crack density of post-coating films was quantified at higher resolutions using a compound microscope. Ink composition, Pt-based catalysts and relative humidity of drying environment were varied in order to understand which combinations resulted in fewer cracks. This material is based upon work supported by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) under the Fuel Cell Technologies Office, Award Number DE-EE0008822.
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SUZUKI, Takahiro, Hiroki TANAKA e Masanori HAYASE. "J0610105 Effects of Drying Rate of Catalyst Ink on Formation of PEFC Catalyst Layers". Proceedings of Mechanical Engineering Congress, Japan 2014 (2014): _J0610105——_J0610105—. http://dx.doi.org/10.1299/jsmemecj.2014._j0610105-.
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Uemura, Suguru, Katsunori Sakai, Takashi Sasabe, Hidetoshi Matsumoto, Hidekazu Sugimori, Kazuhiko Shinohara e Shuichiro Hirai. "Effect of Reaction Products on the PEFC Catalyst Ink Property and Catalyst Layer Quality". ECS Meeting Abstracts MA2020-02, n. 33 (23 novembre 2020): 2137. http://dx.doi.org/10.1149/ma2020-02332137mtgabs.
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Uemura, Suguru, Katsunori Sakai, Takashi Sasabe, Hidetoshi Matsumoto, Hidekazu Sugimori, Kazuhiko Shinohara e Shuichiro Hirai. "Effect of Reaction Products on the PEFC Catalyst Ink Property and Catalyst Layer Quality". ECS Transactions 98, n. 9 (23 settembre 2020): 61–65. http://dx.doi.org/10.1149/09809.0061ecst.