Dura Fuel Cell: Multi-scale investigation for the development of durable and efficient hydrogen fuel cell systems for mobile and stationary applications

EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 1/8 B0812 Dura Fuel Cell: Multi-scale investigation for the development of durable and efficient hydrogen fuel cell systems for mobile and stationary applications Maik Eichelbaum*, Lena Birkner Technische Hochschule Nürnberg Georg Simon Ohm, Nuremberg/Germany; *Contact corresponding authors: www.EFCF.com/ContactRequest Abstract The DuraFuelCell Research Impulse is a collaborative project at the Technische Hochschule Nürnberg funded by the German Research Foundation DFG that aims to gain a deep and comprehensive understanding of all relevant parts and scales of a fuel cell system that influence the two biggest challenges still hindering a broad commercialization: system efficiency and fuel cell lifetime. This is to be achieved by investigating deactivation and its mitigation in polymer-electrolyte membrane fuel cells by systematically combining experimental and computational research as well as material and component development with new operando spectroscopic and sensor technologies along all scales, i.e. from the first molecular deactivation and activation steps, over aging effects in single membrane electrode assemblies and in fuel cell stacks up to complete fuel cell systems including balance of plant. The project tasks are addressed in six main research units, three cross-sectional projects, and are supported by various universities, companies and municipal utilities (“Stadtwerke”): EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 2/8 Introduction Hydrogen and fuel cell technologies have been discussed and researched for decades as a necessary component of a defossilized energy system. The dramatic escalation of the climate crisis with the reaching of irreversible tipping points and the current raw material and energy crisis with unprecedented price jumps for fossil energy sources make it clear that a hydrogen economy has to be implemented immediately. The defossilization of the entire energy system is not realistic without using hydrogen or its derivatives as energy carriers [1]. Hydrogen can solve the storage problem in a highly volatile energy system based on renewable non-base-load energy sources such as wind and solar. The big advantage of hydrogen is its versatility to operate across the transport, heat, industry and electricity sectors, which account for about two-thirds of global CO2 emissions [2]. Fuel cells are essential in this scenario, since they can convert green hydrogen, produced by water electrolysis using local renewable (surplus) electricity or imported from countries with more optimal wind and sun conditions, into electricity and heat. Applications can be found in many areas, e.g. in the transportation sector, in energy-intensive industries and for the supply of power and heat in buildings. In the 2000s, there were already big initiatives and dreams for the use of fuel cells in everyday life. However, these expectations have not been fulfilled in this way. At the moment, an increasing interest in fuel cell technologies can be observed [2]. In the meantime, enormous progress has been made in reducing material and production costs and up-scaling. The increasing relevance of fuel cells is particularly evident in the mobility sector due to the shift in research and technology focus from passenger cars (lowduty vehicles, LDV) to heavy-duty vehicles (HDV) [3,4]. The previous research and technology focus was mainly on reducing fuel cell costs for LDV applications. Now, for stationary and HDV applications with their long lifetimes, the end-oflife performance and thus the fuel cell durability is of much greater importance. Selected current state and ultimate target values for key performance parameters regarding durability and efficiency of polymer-electrolyte membrane fuel cells (PEMFCs) as set by the U.S. Department of Energy (DoE) are summarized in the following table. It is obvious that there is still great room for improvement to achieve a technological and eventually commercial breakthrough, especially in areas such as heavy-duty and stationary applications, where fuel cells are considered now to have the greatest potential [4-6]: Characteristic (Units) Status Ultimate Target Fuel Cell System Lifetime (hours) - 3,900 for LDV - 20,000 for HDV - 8,000 for LDV - 30,000 for HDV - 35,000 for locomotives - > 60,000 for stationary fuel cells - 75,000 – 100,000 for marine applications Fuel Cell (Electric) Peak Efficiency (%) 64 - 50 for 100 kW/ 3 MW Combined Heat and Power (CHP) and Distributed Generation Fuel Cell Systems - 70 for LDV - 72 for HDV CHP Fuel Cell Energy Efficiency (%) > 70 > 90 EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 3/8 1. Scientific Approach In order to address the aforementioned challenges, we started in 2024 at the Technische Hochschule Nürnberg Georg Simon Ohm, Germany the collaborative research project DurFuelCell, which is funded for five years by the German Research Foundation DFG in the framework of the new Research Impulse funding initiative. The focus of this project is on the investigation of aging mechanisms influencing efficiency and lifetime of hydrogen/air PEMFCs for applications in HDVs and as part of a sustainable energy supply in buildings and city districts. Based on our own research and on a literature survey [4,7–13], the following most important aging factors caused by the different PEMFC system components have been identified: PEMFC component Aging process (Electro-)Catalyst Loss of electrochemical active surface area, e.g. due to platinum oxidation, dissolution, migration and redeposition followed by particle Ostwald ripening or coalescence, especially upon fast potential cycling and start-up/ shut-down phases Acute catalyst poisoning and deactivation by impurities in anode or cathode gas due to formation of irreversible adsorbates Catalyst support Electrochemical corrosion of the carbon support, in particular under high local potentials at hydrogen/air fronts Membrane Degeneration followed by increased hydrogen gas permeability, loss of proton conductivity and decreased electrical resistance, induced by attacks of radicals formed at hydrogen/air fronts and catalyzed by precipitated platinum as well as due to mechanical stress, e.g. due to membrane swelling and contraction upon cycling between dry and humid conditions Blocking of acidic sites accompanied by a loss of proton conductivity by acidic/alkaline impurities or metal cations, e.g. released from electrochemical corrosion processes Gas diffusion layer Loss of hydrophobicity of the microporous and gas diffusion layer accompanied by an inhibited transport of the product water out of the cell and therefore increased mass transport limitation, preferably occurring at high temperatures Bipolar plates Electrochemical corrosion, e.g. with release of Fe2+ catalyzing radical formation which can destroy the membrane Balance of plant Service life limitation due to, e.g., failure of the hydrogen, air, water or thermal management system However, the different outcomes of many studies also show the large influence of the specific membrane-electrode assembly (MEA), fuel cell stack size, balance of plant system and operation conditions on the aging effects and efficiency loss of the fuel cell under investigation. This is in particular true for the research regarding HDV and stationary applications, which have not been in focus so far. E.g., impurities introduced from hydrogen gas, ambient air, or other PEMFC and balance of plant components have longer accumulation times during the longer fuel cell lifetimes. Such possible extreme long-term effects have not yet been studied systematically. Furthermore, there are hints that strategies identified to date to mitigate aging and acute poisoning symptoms that work well for LDVs might be inefficient or even counterproductive for HDV and stationary applications, with their much longer service lives and higher efficiency requirements [4]. Higher efficiency is usually achieved by operating the fuel cell at higher voltages and higher temperatures, which also EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 4/8 facilitates thermal management since fewer coolers and cooling surfaces are required. The applicants' experience in joint research with a major commercial vehicle manufacturer at the Future Driveline Campus of the Technische Hochschule Nürnberg Georg Simon Ohm indicates that the challenge of thermal management of low temperature PEMFCs typically operating at temperatures between 70 and 80°C may currently be one of the biggest obstacles to commercialization of fuel cell powertrains. In addition, CHP for stationary applications would also benefit from a higher average operating temperature to more effectively utilize the dissipated heat. However, both high temperature and high voltage operation conditions are additional stressors for the fuel cell and will likely have a negative impact on lifetime. Therefore, much more research is needed to fully understand the relationships between efficiency, lifetime, aging, mitigation strategies and the special operating conditions needed for stationary and HDV applications. Moreover, transferring results from single cell to system level is also not straightforward. E.g., laboratory-scale fuel cells are usually operated under isothermal conditions, whereas in real applications temperature gradients occur in large stacks with the formation of local hotspots. This is even more important in HDV applications, where two or even more stacks - each with ≥100 kWel power - are assembled. In addition, the translation of the end-of-life indication based on a laboratory-scale accelerated stress test into a real service life figure is a major challenge. Moreover, the optimization of one factor at one scale for one particular fuel cell might not consider its possible influence on other aging factors, MEA types, scales, balance of plant systems, etc. In addition, the extension of service life might have a negative impact on the overall system efficiency or on the practical usability due to the need of possibly unfavourable operation conditions. And last but not least, effective operando spectroscopic, electrochemical, and/or sensor technologies operating on all scales are often missing to obtain the needed deep insights into causal relationships between aging and performance. Therefore, we take a holistic approach to our project in order to overcome the aforementioned barriers to knowledge transfer across the different levels of fuel cell research. The relevant aging factors are investigated by working on six main and three cross-sectional research units on different system levels in parallel. New corrosion-resistant PEMFC materials and balance of plant components are brought together with novel operando spectroscopic, electrochemical and sensor techniques in order to design more efficient and more durable fuel cell systems. A particular focus of our investigations is on the operation of fuel cells at temperatures higher than 80°C to facilitate thermal management in HDV and CHP applications and on an innovative air processing unit in order to increase system efficiency while maintaining or even extending the systemic service life. The direct exchange and collaboration between the research units within the Reseach Impulse and the implementation of new innovative measurement and evaluation tools on different fuel cell scales will help to identify the relevance of the fundamental findings of fuel cell aging from individual scales for the entire system. The DuraFuelCell project is hence bringing fundamental and systemic research in a strongly knowledge-oriented approach together and is aiming at a multi-scale investigation of fuel cell aging and efficiency comprehending the following scientific objectives: • Identification of the first molecular steps of reversible and irreversible aging processes at the electro-catalytic sites of fuel cells under operando conditions and of the various physico-chemical loss and degradation mechanisms limiting lifetime and efficiency at single cell level • Development of novel degradation-resistant materials for durable fuel cells • Understanding of aging processes and development of aging mitigation strategies at fuel cell stack level with special focus on thermal management EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 5/8 • Understanding and development of efficient and durable balance of plant systems with special focus on gas processing units • Design of entire fuel cell systems and development, modelling, investigation and optimization of operating concepts for durable fuel cell systems in stationary and heavy-duty transport applications • Development of effective accelerated lifetime tests, novel simulation methods, innovative operando spectroscopic, electrochemical and sensor techniques as well as data-science driven approaches to provide crucial theoretical and experimental data for fuel cell aging and efficiency on all relevant scales and system levels 2. Experiments/Calculations/Simulations Based on the aforementioned scientific goals, the project is divided into the following six main research units: • Understanding fuel cell degradation on a molecular scale • Understanding dynamics of fuel cell degradation processes • Development of degradation-resistant fuel cell materials • Understanding degradation and development of mitigation strategies on fuel cell stack level • Impact of balance of plant (gas supply system) on degradation and efficiency in fuel cell systems for heavy-duty transportation applications • Understanding degradation and efficiency in fuel cell systems for stationary applications • In addition, the following three cross-sectional projects support the six main research units: o Data-based trend and scenario research o Innovative photonic sensors for fuel cell condition monitoring o Simulation and modelling of aging processes The research units and the internal and external cooperation partners cover different scales of fuel cell research, but are intertwined and systematically exchange findings with each other to reflect the holistic project approach. The following table shows the organizational structure of the main six research units and three cross-sectional projects. All units are led by an expert at the Technische Hochschule Nürnberg for the respective field as principal investigator. The compilation of competences enables an interdisciplinary network between chemists, materials scientists, physicists as well as process, electrical and automotive engineers. Complementary external expertise is integrated through the participation of scientists and renowned institutions from the fields of EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 6/8 chemical reaction engineering, electron microscopy and materials testing technology to cover all relevant scales and levels of fuel cell research and development. The application perspective in the transportation and stationary sector is considered by cooperation with companies from the fields of heavy-duty vehicles; turbines, pumps and aggregates; fuel cell stack production; energy supply; hardware and software services; and hydrogen production. Research Unit Title Principal investigator Expertise External cooperation partner A Understanding fuel cell degradation on a molecular scale Prof. Dr. Maik Eichelbaum Professor for Analytical Chemistry with Research Emphasis on Hydrogen/Fuel Cells Prof. Dr. Raimund Horn, Professor for Chemical Reaction Engineering, TU Hamburg; Prof. Dr. Marc Willinger, Professor for Electron Microscopy with Research Emphasis on Energy Materials, TU München B Understanding dynamics of fuel cell degradation processes Prof. Dr.-Ing. André Leonide Professor for Materials of Electrical and Electronic Engineering C Development of degradationresistant fuel cell materials Prof. Dr. Uta Helbig Professor for Crystallography D Understanding degradation and development of mitigation strategies on fuel cell stack level Prof. Dr.-Ing. Frank Opferkuch Professor for Decentralized Energy Conversion and Storage at THN Prof. Dr.-Ing. Matthias Oechsner, Center for Structural Materials, TU Darmstadt; EKPO Fuel Cell Technologies GmbH; MAN Truck & Bus SE E Impact of balance of plant (gas supply system) on degradation and efficiency in fuel cell systems for heavy-duty transportation applications Prof. Dr.-Ing. Georgios Bikas Professor for Thermochemical Systems & Powertrains Be-Rex b.V. F Understanding degradation and efficiency in fuel cell Prof. Dr.-Ing. Ulrich Ulmer Professor for Hydrogen Infrastructure Consolinno Energy GmbH, EAM GmbH & Co. KG, HEITEC Innovations GmbH, EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 7/8 systems for stationary applications Kyros Hydrogen Solutions GmbH, Stadtwerke Bamberg GmbH, Stadtwerk Haßfurt GmbH, Stadtwerke Stuttgart GmbH, WUN H2 GmbH G Data-based trend and scenario research Prof. Dr. Ralph Blum Professor for Business Administration with Focus on Industrial Goods Marketing and Innovation Management H Innovative photonic sensors for fuel cell condition monitoring Prof. Dr.-Ing. habil. Rainer Engelbrecht Professor for Technical Optics and Sensing I Simulation and modelling of aging processes Prof. Dr. Jan Lohbreier Professor for Computational Physics 3. Results The research results and activities achieved in the DuraFuelCell Research Impulse are regularly published on the project website: www.th-nuernberg.de/durafuelcell. 4. Acknowledgment Funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Project-ID 528480942 - FIP 8 is gratefully acknowledged. EFCF 2025: Low-Temp. Fuel Cells, Electrolysers & H2 Processing 1 – 4 July 2025, Lucerne Switzerland https://doi.org/10.5281/zenodo.17476280 B0812 Page 8/8 References [1] Energy Transition 2030: Europe’s Path to Carbon Neutrality, 2020. https://www.leopoldina.org/uploads/tx_leopublication/2020_Energiewende_2030_En _Final_01.pdf. [2] Staffell, I.; Scamman, D.; et int. Ward, K. R. The Role of Hydrogen and Fuel Cells in the Global Energy System. Energy Environ. Sci. 2019, 12 (2), 463–491. https://doi.org/10.1039/C8EE01157E. [3] Sens, M.; Danzer, C.; et int. Kratzsch, M. Hydrogen Powertrains in Competition to Fossil Fuel Based Internal Combustion Engines and Battery Electric Powertrains; 2021. [4] Cullen, D. A.; Neyerlin, K. C.; et int. Kusoglu, A. New Roads and Challenges for Fuel Cells in Heavy-Duty Transportation. Nat. 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