bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complementary Analysis on the SEI of Thin Film Siox Using X-Ray Photoemission Spectroscopy and X-Ray Reflectivity Methods
Authors: Nakamoto Mitsunori , Lu Zijie , Zrikem Khawla , Le Cras Frédéric , Tanaka Masatomo , Benayad Anass , Tardif Samuel , Van Roekeghem Ambroise 
Published: December 2024

Silicon materials are expected as a high-capacity anode material for lithium-ion batteries. However, the life of the cell with such silicon materials tends to be short due to the pulverization of silicon associated with its large volume change, and electrolyte consumptions associated with the continuous growth of solid electrolyte interphase (SEI). Compared to pure silicon anodes, silicon oxide (SiOx) has been reported to mitigate such issues and extend the life of the battery1,2. In this study, we combined ex situ XPS (X-ray photoemission spectroscopy) and operando XRR (X-ray reflectivity) methods to investigate the phase transformations in the thin-film SiOx and the nature of SEI during the first lithiation/delithiation cycle to obtain the insights to improve the cycle performances.
Using ex situ XPS, we examined the depth profile of the thin-film SiOx sample (Figure 1) at some representative potentials during the first cycle. This elucidated the evolution of chemical nature and thickness of the SEI, and simultaneously the irreversible phase changes in the SiOx. In recent years, the operando XRR method has been successfully applied to the pure silicon thin films3,4, revealing the nature (like thickness and electron density) of top and bottom SEI layers in early cycles. In this study, XRR was applied to thin-film SiOx for the first time. The insight from XPS and that from XRR were integrated for a comprehensive understanding on the evolution of the SEI layer and the SiOx electrode. A systematic comparison was made using the electrolytes with FEC and without FEC to better understand the importance of FEC. It was found out that the SEIs in both systems commonly show breathing behaviors, but the thickness of the SEI is almost always smaller in the FEC containing system. These findings can be a foundation for the high-performance batteries.
1. Chen, T.; Wu, J.; Zhang, Q.; Su, X. Recent Advancement of SiOx Based Anodes for Lithium-Ion Batteries. J Power Sources
2017, 363, 126–144.
2. Hsu, C.-H.; Chen, H.-Y.; Tsai, C.-J. Stoichiometry Dependence of Electrochemical Behavior of Silicon Oxide Thin Film for Lithium Ion Batteries. J Power Sources
2019, 438, 226943.
3. Cao, C.; Steinrück, H.-G.; Shyam, B.; Stone, K. H.; Toney, M. F. In Situ Study of Silicon Electrode Lithiation with X-Ray Reflectivity. Nano Lett
2016, 16 (12), 7394–7401.
4. Cao, C.; Steinrück, H.; Shyam, B.; Toney, M. F. The Atomic Scale Electrochemical Lithiation and Delithiation Process of Silicon. Adv Mater Interfaces
2017, 4 (22), 1700771.

Figure 1
Quantifying Individual Electrode Polarization and Elucidating Interactive Phenomena in PEM Fuel Cells
Authors: Li Lulu , Wang Yudong , Xu Nengneng , Zhou Xiao-Dong 
Published: December 2024

Fuel cells (FCs) that utilize hydrogen as fuel represent a clean and advanced energy conversion technology[1]. In the past two decades, FCs have achieved significant breakthroughs through the development of key materials and components. Nevertheless, quantifying the polarization and dynamics of individual electrodes and components under operating conditions remains a challenge for FC systems, which involve multiple physical and electrochemical processes. Electrochemical impedance spectroscopy (EIS), a widely used non-invasive technique, provides extensive information about the charge transport and reaction kinetics in the frequency domain[2]. The distribution of relaxation times (DRT) method further increases the resolution of the impedance in the relaxation domain[3]. In general, various physical and electrochemical processes occurring on the two electrodes manifest as peaks in the DRT plot. The areas corresponding to these peaks quantify the resistance contributed by each respective process. However, the DRT peaks are still highly convoluted, and additional efforts are required to assign the peak contributions and further separate the resistances of cathode processes and anode processes.
In this work, we designed a Pt-wire (Au-wire) micro-reference electrode/ probe (MRE), which is laminated between two PEMs (Nafion® 212), and positioned centrally within the active area. The artifact-free impedance spectra of the cathode and anode under operating conditions were recorded by utilizing the pseudo-reference electrode. The DRT functions of the cathode and anode can add up to the total DRT function of the cell. Under these conditions, The ion conduction resistance, capacitance of the electrode, and contact resistance at the electrode∣∣MRE interface can be quantified. Multiple operation conditions including relative humidity of both electrodes, back pressures, and gas compositions are studied to verify the reliability of the DRT method in PEMFC research. Hence, this study offers a novel approach to guiding the development of high-performance PEMFC by quantifying the resistance associated with various processes in PEMFC components.

Reference:

[1] F. Xiao, T. Chen, Y. Peng, R. Zhang, Fault diagnosis method for proton exchange membrane fuel cells based on EIS measurement optimization, Fuel Cells, 22 (2022) 140-152.
[2] J. Kwon, P. Choi, S. Jo, H. Oh, K.-Y. Cho, Y.-K. Lee, S. Kim, K. Eom, Identification of electrode degradation by carbon corrosion in polymer electrolyte membrane fuel cells using the distribution of relaxation time analysis, Electrochim. Acta, 414 (2022).
[3] Y. Wang, N. Xu, X.-D. Zhou, Quantifying individual electrode polarization and unraveling the interactive phenomenon in solid oxide fuel cells, Next Energy, 1 (2023).
Durability Study of Membrane Electrode Assembly for Heavy-Duty Fuel Cells
Authors: Quesada Calita Maria , Wang Xiaojing , Komini Babu Siddharth , Gawas Ramchandra , Mukundan Rangachary , Borup Rod L. 
Published: December 2024

Polymer electrolyte membrane fuel cells (PEMFCs) are a zero emission replacement for heavy duty applications due to their range, energy density and fast refueling times.[1] In 2020, the U.S. Department of Energy (DOE) lunched the Million Mile Fuel Cell Truck (M2FCT) consortium to fund fuel cell R&D to meet heavy duty truck standards.[2] Durability studies focusing on heavy-duty applications for advanced materials testing under the M2FCT consortium have been extensively explored and continue to be analyzed to standardize the evaluation of next generation fuel cell materials.
This study combines in situ electrochemical characterization with ex situ analysis of single cell PEMFCs membrane electrode assemblies (MEAs) to predict long-term durability for heavy-duty applications. Various accelerated stress test (AST) parameters were analyzed to determine the stressors affecting the long-term durability. Local degradation resulting from repeated high voltage to low current cycles was analyzed by testing state-of-the-art materials. High potential holds at various conditions were analyzed to determine membrane chemical degradation. Repeated wet and dry cycles were performed to test the membrane mechanical durability. In situ electrochemical analysis include mass activity, electrochemical surface area, hydrogen crossover, and polarization curves were collected and compared among the MEAs. Ex situ analysis includes quantification of membrane thinning at end of life and fluoride emission rate measurement for water effluent throughout the test was conducted to study the membrane degradation.

Acknowledgement:

This work was supported by the Hydrogen and Fuel Cell Technologies Office (HFTO), Office of Energy Efficiency and Renewable Energy (EERE), US DOE through the Million Mile Fuel Cell Truck (M2FCT) consortium, technology managers G. Kleen and D. Papageorgopoulos.

References:

David A. Cullen, K. C. Neyerlin, Rajesh K. Ahluwalia, Rangachary Mukundan, Karren L. More, Rodney L. Borup, Adam Z. Weber, Deborah J. Myers, and Ahmet Kusoglu, New roads and challenges for fuel cells in heavy-duty transportation. Nat. Energy, 2021. 6(5): 462-474.

DOE Launches Two Consortia to Advance Fuel Cell Truck and Electrolyzer R&D. 2020; Available from: https://www.energy.gov/eere/articles/doe-launches-two-consortia-advance-fuel-cell-truck-and-electrolyzer-rd.
Understanding PEMFC Catalyst Ink Component Interactions Using Rheo-Impedance Measurement
Authors: Mora Joy Marie , Chuang Po-Ya Abel 
Published: December 2024

Optimizing electrode performance remains a grand challenge for fuel cell researchers, particularly in proton exchange membrane fuel cell (PEMFC) catalyst layers (CLs). These layers are typically fabricated from inks containing carbon-supported platinum catalyst particles and ion-conducting polymer material, dispersed in a solvent solution. Variations in catalyst ink formulations result in distinct interactions among ink components, shaping the microstructure and performance of CLs. Additionally, fabrication processes play a crucial role in determining the final properties and microstructure of these CLs. Therefore, understanding the correlation between precursor ink, catalyst morphology, and performance is essential in materials and design optimization for fuel cell technology.
This study investigates the interactions within PEMFC catalyst ink using various ink component formulations. We employ a combination of rheological and electrical impedance spectroscopy measurements (rheo-EIS) to probe the static and dynamic nature of catalyst ink. The observed properties, coupled with zeta (ζ) potential and dynamic light scattering (DLS) measurements, provide insights on ink agglomeration levels and microstructure evolution. The experimental approach and findings offer a deeper understanding of ink component-CL structure relationships, guiding the engineering of catalyst inks tailored for practical and optimal performance.
Exploring the Impact of Contamination and Ageing on Proton Exchange Membrane Fuel Cells: Insights from Transmission Electron Microscopy
Authors: Pourrahmani Hossein , Ferriday Thomas B. , Oveisi Emad , Bettex Jeremie , Van herle Jan 
Published: December 2024

This paper presents a thorough investigation into the multifaceted impacts of contamination and ageing on the performance and structural integrity of proton exchange membrane fuel cells (PEMFCs) utilizing advanced Scanning Transmission Electron Microscopy (STEM). The study scrutinizes three distinct membrane electrode assemblies (MEAs): pristine, contaminated, and aged over an extensive operational period of 900 hours. Through meticulous analysis encompassing morphology and chemical composition, the intricate alterations induced by these factors are elucidated, providing invaluable insights into PEMFC degradation mechanisms.
While contamination exhibited a seemingly minor influence on carbon distribution, profound effects were discerned on the ionomer and membrane constituents. Notably, a reduction in the perfluorinated backbone of polytetrafluoroethylene (PTFE) was evident, quantified by the ratio , standing at 2.07. This degradation significantly impeded the binding of catalysts and hindered ionic charge conduction, thereby fostering agglomeration and impeding ionic conductivity within the catalyst layer. Moreover, the aged MEA endured substantial carbon corrosion, resulting in the structural compromise of the carbon support layer.
The repercussions of carbon corrosion were manifold, manifesting in a discernible decrease in the electrochemical active surface area (ECSA) attributable to platinum dissolution and re-deposition. Consequently, this led to an uneven distribution of platinum, forming clusters and exacerbating activation overpotential. These findings underscore the intricate interplay between contamination, ageing, and the ensuing structural and electrochemical alterations in PEMFCs, shedding light on critical degradation pathways.
Furthermore, a comprehensive analysis of the aged MEA revealed notable changes in the microstructural characteristics, including an increase in pore size and surface roughness, indicative of progressive degradation mechanisms. These structural alterations were found to directly correlate with deteriorating performance metrics, emphasizing the pivotal role of microstructural integrity in PEMFC functionality.
In conclusion, this study offers valuable insights into the intricate interplay between contamination, ageing, and structural degradation in PEMFCs, highlighting the urgent need for effective mitigation strategies to prolong lifespan and enhance performance. The findings presented herein serve as a crucial foundation for the development of advanced materials and design strategies aimed at enhancing the durability and efficiency of PEMFCs for diverse applications.

Figure 1
Hydrogen Limiting Current Test Diagnostic Tool for Analyzing PEMFC Durability in Accelerated Stress Tests
Authors: Baricci Andrea , Casalegno Andrea , Colombo Elena , Grimaldi Amedeo , Mora Daniele 
Published: December 2024

The durability of Polymer Electrolyte Membrane Fuel Cells (PEMFC) is a crucial factor for enhancing their competitiveness in the heavy-duty vehicle sector thus it is essential to assess the impact of the major degradation mechanisms on the performance and lifetime of the technology. To this end, accelerated stress tests have been standardized over the years with the aim of expediting the development of durable materials and being able to evaluate the durability in MEA. In this framework, it is extremely important to be able to separate different sources of voltage loss. Specifically, the degradation of mass transfer loss is extremely important because impacts the maximum power density available, efficiency and thermal management of the stack. Mass transfer loss is correlated at the material level, to the loss in electrocatalyst active surface (ECSA) being a consequence of the limitations in oxygen transport across the ionomer thin film. In this work mass transfer degradation is analyzed by ASTs that accelerate real-world ageing [1]. In this work, in addition to standard diagnostic tools, hydrogen limiting current test are investigated. Previous work reported that using hydrogen as reacting gas for limiting current test can give additional information on the sources of mass transfer loss compared to oxygen, specifically information on the ionomer thin film resistance [2]. In this work, limiting current tests were carried out as diagnostic tools during ASTs for electrocatalyst durability and novel ASTs that better mimick real-world vehicle operation within the IDFAST H2020 project and in the Italian project PERMANENT to investigate the degradation [2]. Correlation between mass transfer resistance in ionomer between oxygen and hydrogen limiting current test is found. Additional effects in the high potential region are observed and attributed to platinum oxide formation by means of a 1D MEA model that is adopted to investigate this effect.
[1] Spingler F.B., Phillips A., Schuler T., Tucker M.C., Weber A.Z. (2017) International Journal of Hydrogen Energy, 13960-13969
[2] Colombo E., Baricci A., Mora D., Guetaz L., Casalegno A., (2023) Journal of Power Sources, 580 , art. no. 233376
Effects of Gravity on Water Transport in PEM Fuel Cells Via Synchrotron X-Ray Radiography
Authors: Chadwick Eric Alexander , Schulz Volker Paul , Bazylak Aimy 
Published: December 2024

To mitigate the effects of anthropogenic climate change caused primarily by CO2 emissions, sustainable energy technologies must be advanced to eliminate our reliance on CO2-emitting energy sources. Polymer electrolyte membrane (PEM) fuel cells are a promising technology for producing power without carbon emissions and with high efficiencies and scalability [1]. However, the commercial adaptation of PEM fuel cells has been sluggish due to high material costs [2]and inefficiencies caused by liquid water accumulation [2,3]. While major improvements have been made to PEM fuel cell components to improve water management, recent studies have shown that macroscopic changes such as cell orientation and flow direction can have profound effects on fuel cell performance and two-phase flow [3-5].
In this study, to determine the optimal orientation for industrial applications of fuel cells and provide insights on water accumulation as a result of external body forces, we performed operando synchrotron X-ray radiography while varying orientation and reactant flow direction of a PEM fuel cell (Fig. 1a). We observed lower water content in the anode GDL when the flow of reactants was gravity-assisted (45º and 90º), and significantly more water content was observed when reactant flow opposed the force of gravity (315º and 270º). Furthermore, placing the cathode on top (180º) resulted in dramatic increases in anode GDL water accumulation compared to placing the cathode on the bottom (0º). Similar trends in cathode GDL water accumulation were observed but were less pronounced compared to the anode GDL. Electrochemical impedance spectroscopy and analytical modelling revealed that mass transport resistances are strongly correlated to water accumulation in the cathode GDL and especially the anode GDL. Our findings suggest that gravity and flow orientation significantly affect two-phase transport and therefore long-term performance in PEM fuel cells (Fig. 1c).
References:

D. A. Cullen et al., Nat Energy, 6, 462–474 (2021).

J. Wang, Appl Energy, 157, 640–663 (2015).

M. Pan, X. Meng, C. Li, J. Liao, and C. Pan, Int J Green Energy, 17, 603–616 (2020).

M. Ashrafi and M. Shams, Appl Energy, 208, 1083–1096 (2017).

H. Guo, X. Liu, J. F. Zhao, F. Ye, and C. F. Ma, Energy, 112, 926–934 (2016).

Figure 1: a) Experimental schematic showing the fuel cell in the 45°/315° position. b) Liquid water saturation levels in the Anode (top) and Cathode (bottom) GDLs at 0.7 . c) Mass transport resistance of every orientation at each tested current density obtained via electrochemical impedance spectroscopy.

Figure 1
Balancing Performance and Pressure Drop in Ni Foam Flow Fields Via Embedded Channel Design
Authors: Chadwick Eric Alexander , Briand Axel , Seip Tess , Auvity Bruno , Bazylak Aimy , Schulz Volker Paul 
Published: December 2024

To curb the effects of anthropogenic climate change, advancements in sustainable energy storage technologies are needed. Hydrogen storage has proven to be more reliable and scalable compared to other storage technologies due in large part to the high efficiencies and energy density of polymer electrolyte membrane (PEM) fuel cells used to extract energy from hydrogen [1]. However, due to high material costs and performance limitations [2,3], commercial adaptation of PEM fuel cells has been relatively slow [4]. In particular, the flow fields in PEM fuel cells account for 70-90% of the weight and volume, and 18-28% of stack costs, making the optimization of flow field function and weight particularly desirable [5]. Porous metal foams have shown promise as a light-weight alternative to conventional flow fields that can achieve competitive performance to baffle and interdigitated designs, but often suffer from high pressure drops [6].
In this study, we demonstrate the capabilities of porous Ni foams with embedded channels as light-weight flow fields for improving fuel cell performance via enhanced reactant distributions and water management while also reducing the pressure drop. Fuel cell performance using gold coated Ni foams with and without embedded channels was compared to a baseline serpentine flow field. All flow field designs were evaluated at wet and dry RH conditions and at two different compression conditions. We reveal that thick Ni foam flow fields without channels improved performance notably compared to the baseline serpentine flow field due to enhancements in reactant delivery and water removal at both wet and dry RH conditions. Further, the use of embedded channels in both thick and thin foam improved performance at both RH conditions by providing larger pathways for water removal while retaining porous lands for efficient reactant delivery. Thick foams significantly reduced pressure drop and achieved lower variability over the course of the test while thin foams only slightly reduced pressure drop with high variability due to local water droplet buildup. The improved performance, reduced pressure drop, and inherent light-weight design of these foams can significantly reduce energy capacity and power density of next generation fuel cells.
References:

X. Luo, J. Wang, M. Dooner, and J. Clarke, Appl Energy, 137, 511–536 (2015).

J. Wang, Appl Energy, 157, 640–663 (2015).

M. Pan, X. Meng, C. Li, J. Liao, and C. Pan, Int J Green Energy, 17, 603–616 (2020).

D. A. Cullen et al., Nat Energy, 6, 462–474 (2021).

Y. Wang, D. F. Ruiz Diaz, K. S. Chen, Z. Wang, and X. C. Adroher, Materials Today, 32, 178–203 (2020).

W. Yuan, Y. Tang, X. Yang, and Z. Wan, Appl Energy, 94, 309–329 (2012).
(Invited) Evaluation and Characterization of NaCl as an Electrode for Sodium-Ion Batteries
Authors: Moeez Iqra , Park Jae-Ho , Susanto Dieky , Kim Ji-Young , Jung Hun-Gi , Lim Hee-Dae , Chung Kyung Yoon 
Published: December 2024

Sodium-ion batteries (SIBs) have attracted considerable attention as a promising alternative for large-scale energy storage due to their remarkable benefits in terms of resource availability and cost-effectiveness. However, there is still a big difference in energy density between SIBs and lithium-ion batteries (LIBs) that are commercially available, which makes it hard to meet the needs of practical applications. The fabrication of high-energy cathodes has become a successful approach for increasing the energy density of SIBs. This often involves using cathodes that can operate in high-voltage regions.
Herein, we used table salt (NaCl) as a novel cathode material for SIBs, where this electrochemically inactive NaCl was activated by introducing structural defects that induce a phase transition from B1- to B2-type NaCl. It was demonstrated that B2-NaCl could exhibit a high initial capacity of 260 mAh g−1; however, poor cycle stability with unsatisfactory capacity retention was a major challenge for its practical application. For this, additional Na-vacancies were introduced by controlling the upper limit of the cut-off voltage, which helped to accommodate more sodium ions during the next discharge, resulting in increased capacity. Meanwhile, Cl-ions, which are released during NaCl decomposition at high voltage of 4.5 V, are oxidized to form Cl-based organic species at the active material interfaces, which helps to enhance the cycle stability. XPS, SEM, and TOF-SIMS characterizations helped to understand the crucial role of these Cl-based species in protecting the NaCl electrode from undesired side reactions at high voltage. Additionally, the in-situ XRD and XAS studies investigated the relationship between the degree of electrochemical activation and the structural stability of metallic NaxCl. We believe that this study could help in exploring a novel method for generating low-cost and high-capacity electrode material for future energy-storage devices.