Publikationsliste Dr. Florian Lombeck

• Originalarbeiten in wissenschaftlichen Fachzeitschriften
• Konferenzbeiträge

Originalarbeiten in wissenschaftlichen Fachzeitschriften

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2024

• R. Qelibari, E. Cruz Ortiz, N. van Treel, F. Lombeck, C. Schare, A. Münchinger, N. Dumbadze, G. Titvinidze, C. Klose, S. Vierrath
  74 µm PEEK-Reinforced Sulfonated Poly(phenylene sulfone)-Membrane for Stable Water Electrolysis with Lower Gas Crossover and Lower Resistance than Nafion N115
  2024 Adv. Energy Mater., Seite: 2303271

2023

• K. Yildirim, H. Fadlullah, C. Schwarz, F. Lombeck, C. Klose, S. Vierrath, M. Breitwieser
  30μm Thin Anode Gas Diffusion Layers for OptimizedPEM Fuel Cell Operation at 120 °C and Low Relative Humidity
  2023 Adv. Energy Sustainability Res, Seite: 2300179
• S. Koch, L. Metzler, S. Kilian, P. A. Heizmann, F. Lombeck, M. Breitwieser, S. Vierrath
  Toward scalable production: catalyst‐coated membranes (CCMs) for anion‐exchange membrane water electrolysis via direct bar coating
  2023 Advanced sustainable systems, Band: 7, Seite: 2200332

2022

• S. Koch, L. Metzler, S. K. Kilian, P. A. Heizmann, F. Lombeck, M. Breitwieser, S. Vierrath
  Toward Scalable Production: Catalyst-Coated Membranes (CCMs) for Anion-Exchange Membrane Water Electrolysis via Direct Bar Coating
  2022 Adv. Sustainable Syst., Seite: 2200332

2021

• H. Nguyen, F. Lombeck, C. Schwarz, P. A. Heizmann, M. Adamski, H-F. Lee, B. Britton, S. Holdcroft, S. Vierrath, M. Breitwieser
  Hydrocarbon-based Pemion™ proton exchange membrane fuel cells with state-of-the-art performance
  2021 Sustainable Energy and Fuels, Band: 5, Seiten: 3687 - 3699
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  Kurzfassung

  Non-fluorinated hydrocarbon ionomers feature distinct technical, cost, and environmental advantages over incumbent perfluorinated sulfonic acid (PFSA)-based ionomers: they offer improved thermo-mechanical properties at temperatures beyond 90 °C, likelihood of lower material cost, lower gas cross-over, and facile recycling of platinum group metals. In addition, fluorine-free hydrocarbon ionomers are less hazardous to the environment owing to the lack of (per)fluorinated precursors. Yet, the performance of hydrogen fuel cells with hydrocarbon-based ionomers and membranes has been historically largely inferior to the PFSA-based state of the art. In this study, we present wholly hydrocarbon fuel cells exceeding previous literature landmarks by a factor of nearly two, with peak power densities of 2.1 W cm−2 under H2/O2 (atmospheric pressure and 95% relative humidity), and 1.1 W cm−2 under H2/air (250 kPaabs and 50% relative humidity). This improvement was achieved by the use of Pemion™ – a sulfo-phenylated polyphenylene-based cation exchange material – as ionomer in the catalyst layer and as proton exchange membrane with a low thickness of 7 μm, and an optimization of cathode catalyst layer based on PtCo/C. Based on an in-depth study of electrochemical performance under various conditions vs. a state-of-the-art PFSA reference cell, the performances of Pemion™-based cells were found to be more sensitive to changes in relative humidity of inlet gases, but the detrimental influence of high temperatures on performance was significantly reduced. At an operation temperature of 110 °C, 250 kPaabs, and 50% relative humidity, the peak power density (0.96 W cm−2) was 8% higher than the short-side chain PFSA-based reference cell (0.89 W cm−2), highlighting the potential of Pemion™ for next-generation fuel cells for heavy-duty or aeronautic applications.

2020

• Z. Shu, M. Fechtig, F. Lombeck, M. Breitwieser, Roland Zengerle, Peter Koltay
  Direct Drop-on-Demand Printing of Molten Solder Bumps on ENIG Finishing at Ambient Conditions through StarJet Technology
  2020 IEEE Access, Band: 8, Seiten: 210225 - 210233
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  Kurzfassung

  In this paper, we report on a detailed experimental study carried out with the StarJet technology to investigate the mechanical adhesion properties of directly printed solder bumps on electroless nickel immersion gold (ENIG) plated PCB boards. The aim of this study is to determine the maximum bond strength achievable by this method and to find suitable printing parameters that allow for the production of reliable and consistent solder bumps by non-contact printing of molten solder (type SAC305). Molten solder droplets of about 250 μm diameter were printed at melt temperatures between 250 and 400 °C onto ENIG surfaces kept at temperatures in the range of 100 to 200 °C. Using shear force tests, the adhesion of the printed bumps was investigated as a function of the main process parameters: 1. printhead temperature, 2. substrate temperature, and 3. substrate preheating time. The formation of an intermetallic compound (IMC) between the solder and the ENIG was confirmed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) measurements. As a result of the comprehensive experimental parameter study, suitable printing parameters for establishing bond strengths corresponding to maximum shear force values of 3000 to 4000 mN could be found, i.e. high printhead temperature of 400 °C, short preheating and time of < 2 min, and substrate heating at 180 °C The use of flux was found to slightly improve the bond strength and to improve the consistency of the printing results for extended operation times. The achieved high bond strength and the reasonable reproducibility of the printing results qualify the StarJet technology for further investigations regarding applications in the field of direct soldering of microelectronic chips and devices to PCB boards as well as other micro-assembly tasks in the future.
• F. Hegge, F. Lombeck, E. Cruz Ortiz, L. Bohn, M. von Holst, M. Kroschel, J. Hübner, M. Breitwieser, P. Strasser, S. Vierrath
  Efficient and Stable Low Iridium Loaded Anodes for PEM Water Electrolysis Made Possible by Nanofiber Interlayers
  2020 ACS Appl. Energy Mater, Band: 3, Nummer: 9, Seiten: 8276 - 8284
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  Kurzfassung

  Significant reduction of the precious metal catalyst loading is one of the key challenges for the commercialization of proton-exchange membrane water electrolyzers. In this work we combine IrOx nanofibers with a conventional nanoparticle-based IrOx anode catalyst layer. With this hybrid design we can reduce the iridium loading by more than 80% while maintaining performance. In spite of an ultralow overall catalyst loading of 0.2 mgIr/cm2, a cell with a hybrid layer shows similar performance compared to a state-of-the-art cell with a catalyst loading of 1.2 mgIr/cm2 and clearly outperforms identically loaded reference cells with pure IrOx nanoparticle and pure nanofiber anodes. The improved performance is attributed to a combination of good electric contact and high porosity of the IrOx nanofibers with high surface area of the IrOx nanoparticles. Besides the improved performance, the hybrid layer also shows better stability in a potential cycling and a 150 h constant current test compared to an identically loaded nanoparticle reference.

Konferenzbeiträge

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2022

• C. Schwarz, F. Lombeck, H. Nguyen, F. Khan, D. Sultanova, K. Yildirim, M. Breitwieser
  Development of roll-to-roll feasible, direct coating technique for membrane electrode assemblies
  2022 Fuel Cells, Gordon Research Conference, Smithfield, RI, USA, July 24 - 29, 2022
• H. Nguyen, D. Sultanova, F. Lombeck, C. Schwarz, P. A. Heizmann, C. Klose, S. Vierrath, M. Breitwieser
  PEM fuel cells based on novel hydrocarbon ionomers: Approaching state-of-the-art performance
  2022 Fuel Cells, Gordon Research Conference, Smithfield, RI, USA, July 24 - 29, 2022

2021

• H. Nguyen, F. Lombeck, C. Schwarz, P. A. Heizmann, M. Adamski, H-F. Lee, B. Britton, S. Holdcroft, S. Vierrath, M. Breitwieser
  A fluorine-free hydrocarbon-based proton exchange membrane fuel cell with state-of-the-art performance
  2021 23rd European Fuel Cell Forum (EFCF), Lucerne, Switzerland (Online), 2.-5.07.2021
• E. Ortiz, F. Lombeck, M. Kroschel, J. Hübner, L. Bohn, M. von Holst, M. Breitwieser, P. Strasser, S. Vierrath
  Highly efficient low-loaded Ir-anodes proton exchange membrane water electrolysis: concepts to reduce in-plane resistance
  2021 23rd European Fuel Cell Forum (EFCF), Lucerne, Switzerland (Online), 2.-5.07.2021
• P. A. Heizmann, M. von Holst, H. Nguyen, F. Lombeck, C. Schwarz, C. Klose, M. Breitwieser, S. Vierrath
  Linking morphological properties of Pt/C catalysts to electrochemical performances for improved catalysis in fuel cells
  2021 23rd European Fuel Cell Forum (EFCF), Lucerne, Switzerland (Online), 2.-5.07.2021
• S. Vierrath, E. Cruz Ortiz, F. Hegge, T. Böhm, F. Lombeck, M. Breitwieser
  Tackling durability and efficiency in polymer membrane fuel cells and electrolysis
  2021 MRS Seattle/Washington, USA (online), 10. – 14.04.2021
• P. A. Heizmann, M. von Holst, F. Lombeck, H. Nguyen, C. Klose, M. Breitwieser, S. Vierrath
  Understanding the platinum carbon-support interaction for improved catalysis in hydrogen fuel cells
  2021 9th NRW Nano Conference: Innovations in Materials and Applications, Münster, Germany (Online), 21.-23.04.2021

2020

• F. Lombeck, F. Hegge, M. von Holst, C. Klose, S. Vierrath, M. Breitwieser
  Ceramic Nanofibers: A versatile material class to improve Electrochemical Energy Applications
  2020 71st International Society of Electrochemistry, Belgrad, Serbia (Online), 30.08. – 04.09.2020
• H. Nguyen, P. A. Heizmann, F. Lombeck, A. Belletti, B. Britton, S. Vierrath, M. Breitwieser
  Improving the Performance of All-Hydrocarbon PEM Fuel Cells Based on Pemion™ Ionomer
  2020 71st International Society of Electrochemistry, Belgrad, Serbia (Online), 30.08. – 04.09.2020