bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Magnetic Field Analysis for Localizing Defects of Fuel Cell & Electrolyzer Components
Authors: Rasuli Sistan , Witte-Bodnar Kerstin , Grunwald Erik , Naumann Volker , Porstmann Sebastian , Polster Stefan , Ilse Klemens 
Published: February 2024

Production capacities of electrolysis and fuel cell technologies are expected to increase significantly in the upcoming years, reducing costs of stack components through numbering-up. To ensure reliability and durability and reduce costs along the manufacturing process, developing suitable in-line non-destructive diagnostic methods for quality control becomes essential for their industrialization.
In both fuel cell and electrolyzer stacks, the main components' electrical resistance and current density distribution greatly influence stack efficiency and longevity. Here, the flowing electric current generates a magnetic field depending on its strength and direction. Potential defects caused by the manufacturing process, including cracks, defective welding spots, coating adhesion issues, delamination, and contamination, influence the components' electric conductivity and current density distribution and hence the magnetic field distribution.
This work investigates non-destructive diagnostic methods using magnetic field analysis (MFA) to identify changes in the magnetic field distribution and, thus, local electrical resistance and current density distributions of fuel cell and electrolyzer components. The methods used are magnetic field imaging (MFI) and Eddy Current Testing (ECT). MFI analyzes the magnetic field distribution in all three spatial directions to trace electrical currents and identify electrical defects, creating a magnetic field signature that can potentially distinguish between functional and non-functional components along the manufacturing process. ECT measures variations in local conductivity by inducing eddy currents in the sample through an alternating magnetic field generated by a sender coil. These eddy currents create a detectable magnetic field in a receiver and are affected by defects and changes in electrical conductivity. Therefore, the method can characterize sheet resistance and material homogeneity through electrical anisotropy in electrically conductive components.
In initial experiments, ECT measurements on coated and uncoated hollow embossed stainless steel bipolar half plates showed systematic differences depending on quality characteristics resulting in unique patterns and inhomogeneities which require further investigation. Furthermore, experiments with both methods on other stack components will be presented and discussed. In addition, their in-line capability will be assessed and evaluated. However, these first promising results imply that MFA is potentially useful as an in-line, non-destructive diagnostic method for quality control.
Evaluating Ink Structure Using Ultrasonic Spray Coating for PEMFC MEA
Authors: Lee Seon-Ho , Woo Seunghee , Kang Yun Sik , Park Seokhee , Yim Sung-Dae 
Published: February 2024

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.
Illuminating Oxygen Reduction Reaction Kinetics in High Temperature Polymer Electrolyte Membrane Fuel Cells Using EIS
Authors: Giotakos Panagiotis I. , Neophytides Stylianos G. 
Published: February 2024

Owing to their notable power efficiency and zero greenhouse emissions, High Temperature Polymer Electrolyte Membrane Fuel Cells (HTPEMFCs) hold immense promise as a prospective candidate for generating clean energy. However, their commercialization is still impeded by the cathodic Oxygen Reduction Reaction (ORR) kinetics, which after almost half a century not only remain elusive, but constitute the most energy-intensive process, requiring large amounts of the expensive Pt catalyst to mitigate.
In this work we provide solid experimental evidence, that the simple three elementary step Dissociative Adsorption Pathway (DAP) with two intermediate species (Oad and OHad), can accurately capture both the steady state (IV) and the Electrochemical Impedance Spectra (EIS) as well.
Detailed EIS and IV experimental data were recorded at 180 °C under differential conditions, using a single serpentine HTPEMFC with a 4 cm2 active area. The fuel cell operated at the activation regime, where ORR potential losses dominate but mass transport limitations are negligible. The experimental data were successfully fitted with the derived analytic IV and EIS microkinetic model.
The use of the DAP in accordance with the Transitions State Theory (TST), allowed the extraction and analysis of ORR kinetics and energetics. The deconvoluted EIS outlined the important role of the
intrinsic kinetic inertia

, i.e. the outcome of the competitive nature of the elementary reaction steps on the adsorbed intermediate species. Kinetic inertia not only dominated EIS and the polarization resistance, but demonstrated that the commonly used Butler Volmer and apparent Tafel slope kinetic approach is incapable of describing the multistep ORR kinetics. With the help of the Degree of Rate Control (DRC) analysis, we successfully identified the O2(g) dissociative adsorption as the rate limiting step.
Finally, from an energetics perspective, by employing the TST kinetics formulation, we were able to calculate the free Gibbs’ transition states activation (kinetics) and reaction steps’ energies (thermodynamics). These results clarified that, the high ORR overpotential losses stem from the combined strength of both kinetically and thermodynamically imposed barriers, which originate from the high bonding strength of Oad on the Pt surface and the rather high activation energy of the O2(g) adsorption step.
On the Importance of MPL Structural Characteristics for PEM Fuel Cell Performance
Authors: Schweiss Ruediger , Herb Magnus , Earla Raj , Meiser Christian 
Published: February 2024

Gas diffusions layers (GDLs) constitute vital subcomponents of proton exchange membrane fuel cells (PEMFCs) since they participate in all relevant transport processes (gases, vapor, liquid water, electricity and heat).Meanwhile, state-of-the-art GDLs are produced on commercial scale using high volume reel-to-reel (R2R) processes. In almost any case, GDLs are designed as dual-layer structures with a macro-porous carbon fiber-based substrate (backing) and a micro-porous layer (MPL) consisting of carbon particulates bonded with polytetrafluoroethylene (PTFE) binder. A body of scientific work has verified that different aspects of the MPL microstructure and the MPL/macroporous substrate interface play a substantial role in the water management of PEMFCs [1-6].
A systematic study was performed based on a singular backing using different MPL types and penetration levels.A simple method to estimate the micro-porous layer penetration in gas diffusion layers based on data obtained from force-deflection behavior of backings and MPL-coated GDLs is proposed. Comparison with SEM and previously published tomographic studies shows that a good estimate for the extent of MPL intrusion into the backing is obtained.
MPL loading and penetration is shown to affect different ex-situ GDL properties (in-plane gas permeability, electrical and thermal conductivity) as well as the GDL single cell performance characteristics with respect to humification and high current density operation.
Keywords: Gas diffusion layers, Microporous Layer, PEMFC fuel cells

Weber, and J. Newman, “Effects of microporous layers in polymer electrolyte fuel cells”, J. Electrochem. Soc. 152, A677-A688 (2005).

Lee, R. Yip, P. Antonacci, N. Ge, T. Kotaka, Y. Tabuchi, and A. Bazylak, Synchrotron investigation of microporous layer thickness on liquid water distribution in a PEM fuel cell, J. Electrochem. Soc. 162, F669-F676 (2015).

Zhou, S. Shukla, A. Putz, and M. Secanell, “Analysis of the role of the microporous layer in improving polymer electrolyte fuel cell performance”, Electrochim. Acta. 268, 366-382 (2018).

Cho, J. Park, H. Oh, K. Min, E. Lee, and J.Y. Jyoung, “Analysis of the transient response and durability characteristics of a proton exchange membrane fuel cell with different micro-porous layer penetration thicknesses”, Appl. Energy 111, 300-309 (2013).

T. Gostick, M. A. Ioannidis, M. W. Fowler, and M. D. Pritzker, “On the role of the microporous layer in PEMFC operation.”, Electrochem. Comm. 11, 576-579 (2009).

P. Ramasamy, E. C. Kumbur, M. M. Mench, W. Liu, D. Moore, and M. Murthy, “Investigation of macro- and micro-porous layer interaction in polymer electrolyte fuel cells”, Int. J. Hydrogen Energy 33, 3351-3367 (2008).
(Invited) Fuel Cell Component Durability for Million Mile Fuel Cell Trucks
Authors: Borup Rod L. , Weber Adam Z. , Myers Deborah J. , Neyerlin K.C. , Kusoglu Ahmet , Ahluwalia Rajesh , Mukundan Rangachary , Cullen David A. , Spendelow Jacob S. , Kleen Gregory 
Published: February 2024

While significant advances have been made and early commercial fuel cell light-duty vehicles (LDVs) are starting to be produced, fuel cells in the heavy-duty-vehicle (HDV) transportation sector (including trucks, long-haul semitrailers, maritime, trains, etc.) are nascent, despite the fact that advantages of fuel cells compared to both diesel and electric powertrains are very compelling in terms of emissions, charging time, efficiency, power-to-weight ratio, among others. However, the fuel-cell technology for HDVs requires a paradigm shift in fuel-cell research and development compared to LDVs, where the emphasis becomes efficiency and improvements in durability instead of a focus on increased power densities and lower cell costs.
Heavy-duty applications require significantly longer vehicle lifetimes (>25,000 hours/1,000,000 miles for heavy-duty trucks), and therefore require improved fuel cell durability compared to light-duty vehicles. In 2020, HFTO formed the Million Mile Fuel Cell Truck Consortium (M2FCT) that includes a core team of five national laboratories to overcome durability and efficiency challenges in PEMFCs for heavy-duty applications with an initial focus on long-haul trucks.
While targets and testing protocols have been developed for light-duty vehicles, the same level of targets and testing protocols have not been established for heavy-duty transportation. With operational times of greater than > 25,000 hours required, the need for well-developed accelerated stress tests (ASTs) is amplified. Results from these ASTs demonstrate the need for more durable electrode layers and well-controlled potential variations. This presentation will provide an overview of the DOE’s Fuel Cell R&D approach, highlighting past and current activities, as well as strategies to enable fuel cell competiveness for heavy-duty applications.

Acknowledgments

This work was funded through the DOE M2FCT Consortium with thanks to DOE EERE HFTO, Fuel Cell Technologies Office. Team Leader: Dimitrios Papageoropoulos and Technical Development Manager: Greg Kleen.
Nanoscale in-Situ Characterization of Polymer Electrolyte Membrane Fuel Cell Catalyst Layers for Improved Water Management
Authors: Lytle Spencer , Parmar Harsharaj Birendrasingh , Seip Tess , Zhu Lijun , Wang Jian , Bazylak Aimy 
Published: February 2024

Polymer electrolyte membrane fuel cells (PEMFCs) facilitate a sustainable energy infrastructure by offering emission-free electricity generation using renewably sourced hydrogen gas. The electrochemical reactions in a fuel cell occur at platinum-loaded catalyst layers (CLs), which are susceptible to degradation. Obstructing catalyst sites (triple phase boundaries1) with reaction by-products, such as water2,3, is the primary degradation mechanism in PEMFCs. Although various CL designs have been tested for improved electrochemical performance, in situ nanoscale visualization of platinum degradation and water accumulation in the CL at controlled temperature and relative humidity (RH) values are required to understand fundamental water mechanics through platinum and carbon nanostructures.
In this work, we employed scanning transmission X-ray microscopy (STXM) and X-ray absorption fine structure spectroscopy (XANES) to evaluate the effect of temperature on pristine and broken-in fuel cell CLs. We developed a novel CL in-situ sample cell to enable nanostructured characterization of catalyst layers using STXM in a controlled temperature environment. Carbon 1s, Fluorine 1s, and Oxygen 1s spectral edges were probed utilizing near-edge X-ray absorption fine structure spectroscopy (NEXAFS) to reveal chemical degradation mechanisms and differentiate material structure. Through our custom in-situ cell, we demonstrate that the chemical composition and water accumulation throughout the PEMFC CLs at low, intermediate, and high operating temperatures (25°C, 40°C, and 60°C, respectively) can be quantified, along with thermal expansion analyses of the CL and ionomer membrane. Moreover, we reveal realistic structural and chemical characteristics of nanoscale catalysts by distinguishing regions of Nafion® Ionomer, catalyst carbon support, and platinum throughout the PEMFC’s membrane electrode assembly at industrially relevant fuel cell temperatures. The insights from this work will inform strategies to mitigate water flooding from a nanoscale perspective in addition to the novel in-situ spectromicroscopy characterization of current CL features.
1. Fouzaï, I., Gentil, S., Bassetto, V. C., Silva, W. O., Maher, R., & Girault, H. H. (2021). 9(18), 11096-11123.
2. Li, H., Tang, Y., Wang, Z., Shi, Z., Wu, S., Song, D., ... & Mazza, A. (2008). 178(1), 103-117.
3. Kumsa, D. W., Bhadra, N., Hudak, E. M., Kelley, S. C., Untereker, D. F., & Mortimer, J. T. (2016). 13(5), 052001.
Impact of Clamping Force Distribution on Loss Processes in a Segmented PEMFC
Authors: Oppek Philipp , Goosmann Tobias , Weber Andre 
Published: February 2024

The operation of large-scale polymer electrolyte membrane fuel cells (PEMFC) inevitably leads to significant spatial gradients along the gas channels. Depending on the local operating conditions, the physicochemical processes and thus also the resistances in the cell vary, which in turn determine the local performance. In addition, design parameters such as the spatial clamping force distribution have a significant influence on the ohmic contact resistance and the compression of the porous layers and thus the diffusion resistance. Thereby, the influences of these factors on the corresponding resistances are opposite to each other, resulting in conflicting objectives.
To enable an optimization of the operating strategy and the component design, a quantification of the local resistances and their dependencies is essential.
This requires a measurement setup that allows the precise adjustment of the operating conditions and contact pressure along the gas channel, as well as a measurement and analysis method that identifies and quantifies the locally occurring processes.
For this purpose, we are applying electrochemical impedance spectroscopy (EIS) on a segmented cell. In this cell the local clamping force is individually adjusted and continuously measured for each segment enabling measurements at constant clamping force as well as selectable clamping force distributions. The local performance limiting loss processes within the cell are separated by the distribution of relaxation times (DRT) and quantified by a physico-chemical meaningful transmission line model (TLM) as a function of local operating conditions and clamping force [1, 2, 3].
In this contribution an experimental analysis of the ohmic, charge transfer and diffusion resistances will be presented. The impact of contact pressure distribution and operating conditions on resistances and their distribution along the gas channels will be discussed. Furthermore, it is demonstrated how the performance can be optimized by adjusting the contact pressure distribution along the gas channel.
1. H. Schichlein et al., J. Appl. Electrochem. 32, pp. 875-882 (2002).
2. E. Ivers-Tiffée et al., J. Ceram. Soc. Japan 125, pp. 193-201 (2017).
3. M. Heinzmann et al., J. Power Sources 558, 232540 (2023).
Fault Detection and Identification for Polymer Electrolyte Membrane Fuel Cell Stack by External Magnetic Field
Authors: Freisem Leonard , Chadebec Olivier , Cauffet Gilles , Bultel Yann , Rosini Sébastien 
Published: February 2024

Many technological locks prevent the deployment of Proton Exchange Membrane Fuel Cell (PEMFC). Particularly for vehicle applications, cost and durability represent two of the most significant challenges to achieve clean, reliable, and cost-effective PEMFC systems. Solving these shortcomings will be a great opportunity for a decisive breakthrough towards mass-diffusion of the current PEMFC technology. The long-term electrical performance losses are associated to either the degradation of the MEA constitutive materials or due to specific operating conditions (flooding, drying, etc.). In perspective, local current density distribution may support stack-level degradation analyzes as well as effective stack control to mitigate the consequences of degradation due to load cycles (electrochemical, thermal, mechanical and humidity effects) or faults.
External magnetic field measurement (MFM) shows a high potential in PEMFC non-invasive diagnosis. Thus, 2D and 3D current distributions and their anomalies in the fuel cell can be identified independent of the size of the causing fault.
To perform this local characterization, the external magnetic field measurement will enable to model the current density in stationary conditions over the cell surface and for the different cells of the stack. This methodology requires the complementary development of magnetic field techniques and inverse models.
In this work, this challenge is tackled by using tailored defective MEAs and specific operating conditions (flooding, drying, ...) to characterize, how local and overall performances of the MEA are affected and to identify the signatures of the various anomalies.

Figure 1
A Fuel Cell’s Big Brother: Artificial Intelligence for Monitoring Fuel Cells
Authors: Klass Lukas , Kabza Alexander , Sehnke Frank , Strecker Katharina , Hölzle Markus 
Published: February 2024

The operation of fuel cell stacks on test benches today is typically monitored by constant
alarm threshold values for selected operating conditions. However, due to the wide range of
operating conditions of the stacks, this type of monitoring only works for extreme maximum
and minimum operating conditions. Wide setting ranges for thresholds prevent the detection
of minor faults, whereas too narrow limits will interrupt the tests unnecessarily. A particular
challenge is the monitoring of faults that either do not result in a directly measured response
from the fuel-cell stack or that only become noticeable with a time delay. The continuous
improvement of fuel cell stacks over the last years necessarily requires much-improved
monitoring methods, especially for durability tests with an operating time of thousands of
hours. For this reason, a novel monitoring concept using AI-based methods for the operation
of PEM fuel cells on test benches was developed and is being presented.
Firstly, machine-learning based mechanisms for monitoring the operating conditions as set
and controlled by the test bench are shown. Due to the cyclic operation during durability
tests, the operating conditions set at a load point can be compared to the past operating
conditions at the same load point. This proceeding allows the early and accurate detection of
faults caused by the test bench and thereby ensures the usability of the measured data as
well as an early alarm in case of problems.
In addition, a digital twin based method for monitoring the condition of the fuel cell stack is
presented. The deep-learning based digital twin calculates a probabilistic prediction of the
expected voltage of the fuel cell stack based on the current and past operating conditions.
The comparison of expected and measured cell voltage taking the model’s confidence into
account enables the early and precise detection of unforeseen events such as contamination
and thus averts consequential damage to the fuel cell stack. In contrast to physical models,
the digital twin represents a data driven model-ling approach for fuel cells.
The presented methods are applied to real testing data to demonstrate the detection of faults
during the operation of fuel cell stacks on test benches that would have remained
undiscovered by today’s monitoring mechanisms. It shows that the data driven digital twin is
able to predict the fuel cell’s stack voltage with an accuracy of 2.5 mV over 1000 h of unseen
data.

Figure 1