bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of Pt Alloy Catalysts for Oxygen Reduction Reaction on Rde and in MEA for High-Temperature Pemfcs
Authors: Lin Honghong , Hu Zhendong , Lim Katie , Zhou Li , Kim Yu Seung , Wang Liang , Jia Hongfei 
Published: November 2022

High-temperature polymer electrolyte fuel cells (HT-PEMFCs) have advantages in enhanced fuel impurities tolerance, easier heat rejection, and simpler water management[1]. Low-temperature PEMFCs with perfluorosulfonic acid electrolytes (e.g., Nafion) could not provide sufficient proton conductivity in the absence of water when T > 120 °C, limiting the application when a higher temperature is desired. High-temperature (HT-) PEMFCs have been developed by using phosphoric acid (H3PO4)-doped polymer electrolyte (e.g., polybenzimidazole, quaternary ammonium biphosphate ion pair coordinated polyphenylene, etc.) [2-4], where H3PO4 can conduct proton at high temperature up to 200 °C. Such change of the reaction environment, however, also affects oxygen reduction reaction (ORR) kinetics. Despite of a facilitated reaction kinetics under high temperature, a high Pt loading is still demanded in state-of-the-art HT-PEMFCs. To enhance ORR activity and increase Pt utilization, here we employ a strategy to alloy Pt with another transition metal (M), which has been demonstrated to be effective in LT-PEMFCs. In this study, Pt and Pt-M catalysts were used to investigate the alloy effect on the adsorption strength of H3PO4 and ORR in both half-cell rotating disk electrode (RDE) and membrane electrode assembly (MEA). In RDE study, the competition adsorption of phosphoric acid has led to a suppression on ORR activity on all catalysts, with less impact on ORR at 160 °C using pure H3PO4 than RT using 1 M H3PO4. Since alloying not just affects the O binding energy, but also H3PO4 adsorption, a different trend of ORR on Pt-M alloy catalysts was resulted in the presence of H3PO4. The alloy effect was further studied in MEA at 160 °C, which also indicates the effectiveness of using HT-RDE setup for HT-ORR catalyst screening.

Reference:

[1] Gittleman, C. S.; Jia, H.; De Castro, E. S.; Chisholm, C. R. I.; Kim, Y. S. Proton Conductors for Heavy-Duty Vehicle Fuel Cells. Joule
2021, 5 (7), 1660–1677.
[2] Pingitore, A. T.; Huang, F.; Qian, G.; Benicewicz, B. C. Durable High Polymer Content m/ p-Polybenzimidazole Membranes for Extended Lifetime Electrochemical Devices. ACS Appl. Energy Mater.
2019, 2 (3), 1720–1726.
[3] Lee, K. S.; Spendelow, J. S.; Choe, Y. K.; Fujimoto, C.; Kim, Y. S. An Operationally Flexible Fuel Cell Based on Quaternary Ammonium-Biphosphate Ion Pairs. Nat. Energy
2016, 1 (9).
[4] Lim, K. H.; Lee, A. S.; Atanasov, V.; Kerres, J.; Park, E. J.; Adhikari, S.; Maurya, S.; Manriquez, L. D.; Jung, J.; Fujimoto, C.; Matanovic, I.; Jankovic, J.; Hu, Z.; Jia, H.; Kim, Y. S. Protonated Phosphonic Acid Electrodes for High Power Heavy-Duty Vehicle Fuel Cells. Nat. Energy
2022, 7 (3), 248–259.
(Invited) Material Requirements for PEM Fuel Cell in Heavy Duty Applications
Authors: Weidler Natascha , Vasquez Mariana , Mahmood Rafat , Jurjević Adrian , Reindl Michael 
Published: November 2022

The membrane electrode assembly (MEA) is the core component of the fuel cell stack. Depending on the fuel cell application, lifetime requirements between 10 000- 20 000 hours must be met. The definition of material requirements for fuel cell operation is a big challenge due to the complexity of electrochemical degradation mechanisms and the lack of knowledge about the acceleration factors between different test integration levels. In addition, limited test capacity makes model test development necessary.
Here, we want to present our approach to generate a lifetime prediction model on basis of model stress tests. Defining so called translation factors (structural descriptors) we determine acceleration factors between single cell- stack- and system testing for specific automotive stressors such as Air-Start- Ups and Potential- Cycling. Finally, material requirements are deviated from the life-time predicting model tests.
Understanding the Electrochemical Dissolution of Polymer Electrolyte Fuel Cell Cathode Catalysts for Heavy Duty Applications Using Online ICP-MS
Authors: Kariuki Nancy N. , Wang Xiaohua , Myers Deborah J. , Ahluwalia Rajesh 
Published: November 2022

Fuel cells for heavy-duty vehicles (HDVs) have attracted considerable attention because of their unique scalability, better fuel economy, and less demand for hydrogen refilling infrastructure relative to the light-duty vehicle application.1 However, the HDV application requires more stringent fuel cell durability, up to 25,000 h or 1 million miles of operation and increased efficiency. 1-2 Cathodes with relatively high Pt loading (~0.3 mg-Pt/cm2) have drawn extensive attention over initially highly active but unstable Pt-transition metal (Pt-TM) alloy3 catalysts owing to their capability of delivering high performance over long HDV lifetime. To fully exploit the potential of Pt in the HDV cathodes, new insights into the relationship between different drive cycles and operating conditions of HDVs and durability are needed with a particular emphasis on understanding the mechanisms for dissolution of Pt. Several mechanisms for dissolution of platinum have been proposed including direct Pt dissolution and electrochemical oxidation of the Pt surface atoms followed by chemical dissolution of the resulting Pt surface oxide. This presentation will outline the dissolution of Pt under various operating conditions in an electrochemical flow cell system connected to an inductively-coupled plasma-mass spectrometer (ICP-MS) capable of detecting trace concentrations (<ppb) of dissolved elements in solution. The electrochemical data combined with the ICP-MS data are used to evaluate the influence of various factors such as potential, potentiodynamic profile parameters (e.g., scan rate, upper and lower potential limits), Pt catalyst particle size, and support type on the dissolution processes in acidic electrolytes at room and elevated temperatures.
Acknowledgements
This work was supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) through the Million Mile Fuel Cell Truck (M2FCT) Consortium. Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, also under contract DE-AC-02-06CH11357.
References

A. Cullen, K. C. Neyerlin, R. K. Ahluwalia, R. Mukundan, K. L. More, R. L. Borup, A. Z. Weber, D. J. Myers, and A. Kusoglu, Nat. Energy, 6, 462 (2021).

Marcinkoski, et al. Hydrogen Class 8 Long Haul Truck Targets (US Department of Energy, 2019);https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdf

L. Borup, et al., Curr. Opin. Electrochem.
21, 192–200 (2020).
Operando
57 Fe Mössbauer Spectroscopy of Fe-N-C Catalysts during Oxygen Reduction Reaction
Authors: Ni Lingmei , Gallenkamp Charlotte , Kübler Markus , Theis Pascal , Bill Eckhard , Krewald Vera , Kramm Ulrike I. 
Published: November 2022

Proton exchange fuel cells (PEFCs) are a clean technology for efficient conversion of chemical into electrical energy and are specifically promising for the decarbonization of heavy duty vehicles [1]. Currently, the drawback of PEFCs is the high cost of Pt-based catalysts used for cathode and anode, which hinders their commercialization. [2] The rapid development of FeNCs holds promise for replacing Pt-based catalysts for the oxygen reduction reaction (ORR). The nature and characterization of the FeNC active sites is a challenging subject of research, and the exact structure of intrinsic active center for FeNC catalysts is still under debate. [3-6]

57Fe Mössbauer Spectroscopy is powerful in obtaining knowledge of iron sites, with respect to structural composition, electronic states as well as magnetic environment [3,7-9]. To solve the debate, 57Fe Mössbauer experiments were carried out under ex situ, in situ, or operando conditions to identify iron signatures and their changes induced by different conditions. On the basis of our in situ results of three differently prepared catalysts, two transitions between the oxygenated and deoxygenated state were found and assigned to sites involved in the direct and indirect ORR. [10-11] In order to gain an in-depth understanding of active sites operando conditions (thus during ORR) were performed for the FeNC catalyst that exhibited the strongest change during in situ testing. One iron signature (D4) gets exclusively formed under ORR conditions and its intensity scales with the ORR current. Together with density functional theory calculations the overall set of data enables us to make important conclusions on the ORR mechanism on FeNC catalysts.
Literature:
[1] M. K. Debe, Nature. 486, 2012, 43−51.
[2] C. Sealy, Mater.Today.11, 2008, 65.
[3] S. Wagner, H. Auerbach, et al. Angew. Chem. 131.31, 2019, 10596-10602.
[4] A. Zitolo, V. Goellner, et al. Nat. Mater. 14.9, 2015, 937.
[5] X.,Li, C. Cao, et al. Chem. 6, 2020, 3440–3454.
[6] J. Li, M. T. Sougrati, et al. Nat. Catal. 4, 2021, 10–19.
[7] U.I. Kramm, M. Lefèvre, et al. J. Am. Chem. Soc. 136, 2014, 978-985.
[8] U.I. Kramm, J. Herranz, et al. Phys. Chem.Chem.Phys. 14, 2012,11673-11688.
[9] U.I. Kramm, L. Ni, et al. Adv. Mater.31.31, 2019, 1805623.
[10] L. Ni, C. Gallenkamp, et al. Adv. Energy Sustainability Res. 2, 2021, 2000064.
[11] L. Ni, P. Theis,et al. Electrochim. Acta. 395, 2021, 139200.
Redox Behavior and ORR Catalytic Activity of Fe-N-C Electrocatalysts in Various Electrolytes and in the Presence of Probe Molecules
Authors: Wang Xiaoping , Park Jaehyung , Ferrandon Magali , Zeng Yachao , Zhang Hanguang , Wu Gang , Zelenay Piotr , Myers Deborah J. 
Published: November 2022

Materials in the Fe-N-C family are the most promising platinum group metal-free (PGM-free) catalysts for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs). Significant progress has been made in recent years in improving both the ORR activity and durability of the Fe-N-C catalysts. However, further improvements are needed, especially in long-term performance durability in hydrogen-air PEFCs, to enable use of these catalysts in practical applications, such as powering light and heavy-duty vehicles. One of the major factors that hinder the further enhancement of the catalysts is the lack of clear understanding of the nature of the active sites in the Fe-N-C catalysts that catalyze the ORR reaction, due to the complexity of the Fe-N-C catalysts composition and structure. The most active Fe-N-C catalysts have been synthesized by pyrolyzing iron salts or other iron-containing compounds with zinc-based zeolitic imidazolate frameworks (ZIFs) and/or phenanthroline (as carbon and nitrogen sources), or by heat treating iron-substituted ZIFs. It has been shown that many synthesis variables, such as type of iron precursors, the metal and carbon-nitrogen macrocycle ratio, the heat treatment temperature, atmosphere, and temperature profile, all affect the properties and structure and thus the activity and stability/durability of the resulting catalysts. In order to further improve the Fe-N-C catalysts, it is critical to gain insights into the origins of ORR activity and the reaction mechanism. In this work, the redox behavior of different Fe-N-C catalysts, synthesized by a variety of techniques mentioned above, and correlation of this redox behavior with ORR catalytic activity in different electrolytes will be discussed and the effect of nitric oxide gas-phase adsorption on the catalyst redox feature and ORR activity will be presented. The implication of these results on the identity or identities of the ORR active sites of the Fe-N-C catalysts will be discussed.
This work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) under the auspices of the Electrocatalysis Consortium (ElectroCat 2.0). This work utilized the resources of the Advanced Photon Source, a U.S. DOE Office of Science user facility operated by Argonne National Laboratory for DOE Office and was authored by Argonne, a U.S. Department of Energy (DOE) Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.
(Invited) Decoupling the Contributions of Different Instability Mechanisms to the Fuel Cell Performance Decay of Fe-Based O2-Reduction Catalysts
Authors: Herranz Juan , Ünsal Secil , Saveleva Viktoriia , Ebner Kathrin , Kübler Markus , Theis Pascal , Lee Jongmin , Artiglia Luca , Schmidt Thomas J. , Boillat Pierre , Kramm Ulrike I. 
Published: November 2022

The last decade of research on Fe-based O2-reduction single atom catalysts (SACs) has led to the development of SACs with an initial polymer electrolyte fuel cell (PEFC) performance close to that of Pt-based catalyst layers (CLs). However, these inexpensive materials generally suffer from a fast performance decay that has been ascribed to several mechanisms that can be simultaneously at play during device operation. These include (i) the demetallation of the SACs’ active sites; (ii) the potential-induced corrosion of the carbonaceous matrix that hosts these active centers; and/or (iii) the chemical degradation of the CL-ionomer, active sites and/or carbon support by radicals derived from the H2O2 produced as an O2-reduction by-product. Unfortunately, little is known regarding the relative contributions of these mechanisms to the overall PEFC-performance loss and as a function of the operative conditions – a missing understanding of pivotal importance for the design of strategies to mitigate this instability.
With this motivation, this contribution will start with a comparison between the device stability in the course of 30 min holds at various currents of two type of SACs featuring similar beginning-of-life PEFC-performance. Particular attention will be paid to the effect of the catalyst loading on the observed degradation, which will be linked to the operando mapping of the distribution of liquid water within these materials’ CLs based on neutron imaging. In a subsequent step, we will present the results derived from a stability protocol in which the combination of different cathode gas feeds (i.e., air vs. N2) and potential hold durations allow decoupling the relative contributions of the above deactivation mechanisms to the overall performance decay. This requires a careful assessment of the kinetic, ohmic and mass transport overpotentials (and changes thereof in the course of the stability measurements) based on Tafel analyses and electrochemical impedance spectroscopy measurements. Moreover, these results are again complemented by an assessment of the protocol-induced changes in catalyst morphology and surface chemistry based on transmission electron microscopy and X-ray photoelectron spectroscopy measurements.
In summary, this contribution will showcase our efforts to deconvolute the relative effects of various deactivation mechanisms to the overall PEFC-performance loss of SAC-CLs.
Degradation Acceleration-Factor Analysis for Platinum Group Metal (PGM)-Free Polymer Electrolyte Fuel Cell Cathodes
Authors: Beltran Diana , Zeng Yachao , Wu Gang , Li Xianglin , Litster Shawn 
Published: November 2022

This work explores designs and methods that can mitigate degradation and can be used to expand models to predict PGM-free fuel cell degradation due to voltage cycling during accelerated stress tests (AST) and constant potential holds, specifically current density loss over time. The motivation behind investigating degradation mechanisms is that most of the recent advances have mostly focused on enhancing initial electrocatalytic activity, and not on catalyst stability. Advancements in catalyst stability are less substantial and are well below the level for commercialization. The objective is to determine the impact of the operating point on degradation rate in membrane electrode assemblies (MEAs) and to perform time-efficient evaluation of degradation acceleration factors on a single MEA. The preliminary AST cycling results show that reducing temperature and upper potential cycling limit considerably reduces degradation rates. This work can help identify operating points that optimize between performance and durability using empirical data. Ultimately, the correlations extracted from this work can be applied into drive-cycle models for PGM-free catalysts for simulation-based lifetime performance forecasting.
This work was partially supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy under grant DE-0008440 (Prime: University of Kansas).
Synthesis and Characterisation of High Performing Heteroatom Doped Carbon Catalyst for Oxygen Reduction Reaction (ORR) in Alkaline Fuel Cells
Authors: Baburajan Aravind B , Ramya Krishnan , Chandrabose A 
Published: November 2022

Alkaline fuel cell (AFC) routing platinum-free electrocatalysts are one of the potential frontiers to enable its use in widespread applications. PGM catalysts have alwaysbeen preferred andwidely utilised due to their enhanced intrinsic activity and superior performance. Its high cost and less abundance brought attention to heteroatom doped carbon-based electrocatalysts that offer comparable performance, tunable selectivity and simple synthesis route. The lack of efficient catalysts hampers the performance, peak power density and longevity of the cell due to sluggish ORR activity.
In this article, Heteroatom-doped carbon (F, N/F and N/S/F) is prepared using PVDF-HFP polymer as a precursor. The polymer is mixed with urea or ThioUrea concerning the required dopant and pyrolyzed at 900 ºC for 3 hours at a heating rate of 5 deg per min in an inert atmosphere. The enhanced performance is obtained from the N/F- doped carbon which shows an onset potential (E = 1.04V vs. RHE), a diffusion-limited current density(j) of 6.12 mA/cm2 in 0.1M KOH, which is comparatively better than the F-doped and N/S/F-doped carbon. The number of electrons (n) involved in the ORR activity was calculated to be 3.99, 3.98, 3.85 for N/F-C, N/S/F-C and F-C respectively. This suggests a 4e- pathway indicating efficient operation for the Alkaline electrochemical cell. The systematic studies exhibit an increased ORR activity in the case of the N/F-doped carbon electro-catalyst due to a combined synergistic effect of hetero-atoms and high surface area. Heteroatom doping and the activity in the carbon material were confirmed by all the necessary physical and electrochemical characterisations.

Keywords: Hydrogen, Alkaline Fuel cell, AFC, Oxygen reduction reaction, ORR catalyst
Development of Li Metal Batteries with Improved Safety
Authors: Zhang Ji-Guang , Cao Xia , Xu Wu , Kim Ju-Myung 
Published: November 2022

Development of Li metal batteries (LMBs) has attracted worldwide attention in recent years due to their much higher theoretical energy densities than those of conventional Li ion batteries. LMBs with high energy density and long cycle life have been demonstrated by several institutions and companies recently.1,2 LMBs may be safe in their early stage of cycling due to the small geometric surface area of Li metal anode. However, after long term cycling, mossy/dendritic/“dead Li” will form eventually. They will not only lead to the increase of cell thickness, but also lead to powdered Li which pose a safety concern when exposed to air in the extreme case of mechanical damage, especially for their large scale applications.3 Thus, a paradigm change in the electrolyte design is required to minimize the formation of “dead Li” and improve the thermal stability of the batteries. In this work, several approaches have been used to improve the thermal stability of LMBs. (1) Use of electrolyte with high coulombic efficiency to minimize the formation of “dead Li” or mossy Li; (2) use of non-flammable solvent in electrolyte; (3) use of solvent with high boiling point and high flash point. (4) use of electrolyte enabling formation of large size of Li deposition with minimal surface area. This will enable the formation of a lithiophobic SEI layer which can accommodate stress/strain during large volume changes. (5) Screening additives to improve Li CE and safety. The electrolytes with improved safety/stability at extreme conditions will also be reported in this work.
1 Niu, C. et al. Balancing interfacial reactions to achieve long cycle life in high-energy lithium metal batteries. Nature Energy, (2021).
2 Hu, Q. Li-metal batteries, https://s29.q4cdn.com/695431818/files/doc_presentation/2022/03/March-2022-Investor-Presentation.pdf (2022).
3 Louli, A. J. et al. Diagnosing and correcting anode-free cell failure via electrolyte and morphological analysis. Nature Energy
5, 693-702, (2020).
The SEI on Lithium Metal Anodes: From Understanding to Enhancement
Authors: Kühn Sebastian Paul , Weintz Dominik , Winter Martin , Cekic-Laskovic Isidora 
Published: November 2022

Lithium metal batteries (LMB) have risen back into focus of battery research in resent years, due to the high theoretical specific capacity of the lithium metal anodes (3860 mAh g-1).[1] However, the utilization of lithium metal as an anode material requires an in depth understanding of the solid electrolyte interphase (SEI) on lithium metal electrodes, since its formation, composition and electrochemical characteristics significantly impact important LMB lifetime parameters, e.g. lithium stripping/plating behaviour, dendrite growth and in operando electrolyte consumption.[2]

Lithium metal electrode performance is influenced by a variety of different, however often overlooked factors, e.g. the native passivation layer, inevitably present on each lithium metal electrode surface, which has only recently gathered more attention as an influencing factor in respect to SEI characteristics.[3] The presented research utilizes the preformation of an uncontaminated SEI on the lithium metal electrode surface to circumvent the influence of native lithium metal passivation. A systematic study of different preformed SEIs resulted in a better understanding of the influence by different electrolyte components on relevant SEI characteristics, namely, selected conducting salts (LiFSI, LiPF6) and functional additives (VC, FEC). Analyses of the SEIs electrochemical properties, composition, morphology and dynamics were conducted via stripping/plating experiments as well as in operando EIS, SEM (incl. cryogenic cross section and post mortem) and XPS (post mortem) measurements. Finally, careful tailoring of the preformed SEI was shown to have an enhancing effect on NMC811||Li cells, increasing the LMB lifetime by up to 25%. Furthermore, the application of a tailored preformed SEI has also shown a positive impact on the performance of solid state LMBs.
The presented results highlight the importance of an in depth understanding regarding the cause and effect of varying electrolyte components on the SEIs characteristics. This understanding will ultimately have a significant impact on the research towards enhanced and reliable LMB performance and future applicability.

References:

[1] D. Jin, J. Park, M. H. Ryou, Y. M. Lee, Adv. Mater. Interfaces
2020, 7, 1–17.
[2] B. Horstmann, J. Shi, R. Amine, M. Werres, X. He, H. Jia, F. Hausen, I. Cekic-Laskovic, S. Wiemers-Meyer, J. Lopez, D. Galvez-Aranda, F. Baakes, D. Bresser, C.-C. Su, Y. Xu, W. Xu, P. Jakes, R.-A. Eichel, E. Figgemeier, U. Krewer, J. M. Seminario, P. B. Balbuena, C. Wang, S. Passerini, Y. Shao-Horn, M. Winter, K. Amine, R. Kostecki, A. Latz, Energy Environ. Sci.
2021, 14, 5289–5314.
[3] S. Otto, T. Fuchs, Y. Moryson, C. Lerch, B. Mogwitz, J. Sann, J. Janek, A. Henss, Appl.
Energy Mater.
2021, 4, 12798–12807.