@article{LabandEskenPollerbergetal.2024, author = {Laband, Dana Laureen and Esken, Henning and Pollerberg, Clemens and Joemann, Michael and Doetsch, Christian}, title = {Analysis of the Potential for Thermal Flexibility of Cooling Applications}, series = {Energies}, volume = {2024}, journal = {Energies}, number = {17(8), Artikel Nr. 4685}, publisher = {MDPI}, doi = {10.3390/en17184685}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-47285}, pages = {19}, year = {2024}, abstract = {The feed-in of electricity from renewable energies, such as wind or solar power, fluctuates based on weather conditions. This unpredictability due to volatile feed-in can lead to sudden changes in energy generation so that solutions ensuring grid stability need to be implemented. The cooling sector offers the opportunity to create flexibilities for such balancing, with this study focusing on the thermal flexibilities that can be provided by cooling applications. Various cooling-demand profiles are investigated with respect to their load profile and their impact on flexibility is analysed. In addition to the cooling demand, scenarios of different storage dimensions are considered. As a result, it shows that an increasing base-load level and increasing operating-load duration have a negative effect on flexibility, while an increasing full-load duration is beneficial for flexibility. Storage size also has a strong impact as higher storage capacity and storage performance indicate higher flexibility, whereas above a certain size they only provide little added value.}, language = {en} } @article{RostBrodmannZekornetal., author = {Rost, Ulrich and Brodmann, Michael and Zekorn, Bruno and Peinecke, Volker and Radev, Ivan and Podleschny, Pit Yannick}, title = {PEM fuel cell electrode preparation using oxygen plasma treated graphene related material serving as catalyst support for platinum nanoparticles}, series = {Materials today. Proceedings}, volume = {4}, journal = {Materials today. Proceedings}, number = {Supplement 2}, issn = {2214-7853}, doi = {10.1016/j.matpr.2017.09.195}, pages = {S249 -- S252}, abstract = {This work deals with the preparation and investigation of polymer electrolyte membrane fuel cell (PEMFC) electrodes, which are obtained using gas diffusion layers coated with graphene related material (GRM) serving as a catalyst support for platinum nanoparticles. PEMFC electrocatalysts have been prepared by pulsed electrochemical deposition of platinum particles from hexachloroplatinic acid. Prior to GRM decoration with platinum, the graphene structures are functionalized by oxygen plasma treatment. This leads to oxygen containing functional groups on the GRM outer surface, providing an improved hydrophilic behavior, thus favoring the Pt deposition process. Membrane electrode assemblies (MEAs) with the so prepared electrodes are investigated in-situ in our fuel cell test system. Polarization plots (in-situ cell performance) using these MEAs have been tested under different operational conditions.}, language = {en} } @article{RostMunteanMargineanetal.2016, author = {Rost, Ulrich and Muntean, Roxana and Marginean, Gabriela and Merino, Cesar and Diez, Roberto and Vaszilcsin, Nicolae and Brodmann, Michael}, title = {Effect of Process Parameters for Oxygen Plasma Activation of Carbon Nanofibers on the Characteristics of Deposited Platinum Nanoparticles as Electrocatalyst in Proton Exchange Membrane Fuel Cells}, series = {International Journal of Electrochemical Science}, volume = {2016}, journal = {International Journal of Electrochemical Science}, number = {Volume 11, Issue 11}, publisher = {Elsevier}, issn = {1452-3981}, doi = {10.20964/2016.11.55}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-9509}, pages = {9110 -- 9122}, year = {2016}, abstract = {In the polymer electrolyte membrane fuel cells (PEMFC) state of the art, rare and expensive platinum group metals (PGM) or PGM alloys are used as catalyst material. Reduction of PGMs in PEMFC electrodes is strongly required to reach cost targets for this technology. An optimal catalyst utilization is achieved in case of nano-structured particles supported on carbon material with a large specific surface area. In this study, graphitic material, in form of carbon nanofibers (CNF), is decorated with Pt particles, serving as catalyst material for PEMFC electrodes with low Pt loading. As a novelty, the effect of oxygen plasma treatment of CNFs previously to platinum particle deposition has been studied. Electrodes are investigated in respect of the optimal morphology, microstructure as well as electrochemical properties. Therefore, samples are characterized by means of scanning electron microscopy combined with energy dispersive X-ray analysis, transmission electron microscopy, thermogravimetry, X-ray diffraction as well as X-ray fluorescence analysis. In order to determine the electrochemical active surface area of catalyst particles, cyclic voltammetry has been performed in 0.5 M sulphuric acid. Selected samples have been investigated in a PEMFC test bench according to their polarization behavior.}, language = {en} } @article{KazamerTackSpreeetal.2025, author = {Kazamer, Norbert and Tack, Meike and Spree, Mathias and Underberg, Martin and Rost, Ulrich and Reichenberger, Sven and Cieluch, Maximilian and Salih, Haujin and Wirkert, Florian Josef and B{\"o}hm, Leonard and Roth, Jeffrey and Nallathambi, Varatharaja and Gault, Baptiste and Baer, Christoph and Orend, Kerstin and Barcikowski, Stephan and H{\"u}lser, Tim and Brodmann, Michael}, title = {Ultrasonically Deposited Boron-Doped Silicon Decorated with Laser-Generated Iridium Nanoparticles as Manufacturing Approach for OER Electrodes in PEM Water Electrolysis}, series = {Advanced Materials Interfaces}, volume = {2025}, journal = {Advanced Materials Interfaces}, number = {Volume 12, Issue 8}, publisher = {Wiley}, doi = {10.1002/admi.202400765}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-46883}, pages = {13}, year = {2025}, abstract = {The study introduces flexible and scalable manufacturing approach for electrodes utilizing boron-doped silicon as conductive support for iridium nanoparticles, addressing the challenges of cost and scarcity associated with noble catalysts for oxygen evolution reaction (OER). Colloidal Ir nanoparticles are synthesized via pulsed-laser ablation (≈4-7 nm) and decorated on B-doped Si (≈100 nm) through electrostatic adsorption. Titanium substrates are ultrasonically sprayed with Si:B - Ir and Ir nanoparticles with very low iridium loading of 12 wt.\%. Crystalline Ir phases (Ir(111), Ir(200)) are observed and known to enhance the OER mechanism. Additionally, atom probe tomography confirms that the Si support particles contained 0.03-0.5 at.\% of boron throughout the entire particle, while electrical permittivity and through-plane measurements reveal a positive impact of B-doped Si on the electrical conductivity of the nanocatalysts and of the ultralow-loaded catalyst coated Ti substrates (0.12 mgIr cm-2), respectively. Rotating disk electrode results show pronounced oxidation peaks for decorated Ir nanoparticles. The Si:B-Ir 4 nm catalyst exhibits the highest turnover frequency (2.62 s-1) and a competitive electrochemical surface area (25 m2 gIr-1) compared to Si:B-Ir 7 nm (0.96 s-1; 37.5 m2 gIr-1) and Ir black (0.24 s-1; 5 m2 gIr-1). The overall analysis of the parameters highlights a performant catalytic efficiency, through balancing activity and reaction kinetics effectively.}, language = {en} } @article{BoehmCieluchKazameretal.2025, author = {B{\"o}hm, Leonard and Cieluch, Maximilian and Kazamer, Norbert and Wirkert, Florian Josef and Marginean, Gabriela and Apfel, Ulf-Peter and Brodmann, Michael}, title = {Electrodeposition of Mo-Rich NiMo Catalysts: Effect of Deposition Parameters and Oxygen Content on the Alkaline Hydrogen Evolution Reaction Activity}, series = {ChemElectroChem}, volume = {2025}, journal = {ChemElectroChem}, publisher = {Wiley-VCH}, doi = {10.1002/celc.202500300}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-48327}, year = {2025}, abstract = {Electrodeposited Mo-rich NiMo catalysts offer enhanced catalytic activity for the alkaline hydrogen evolution reaction (HER) and provide an electrically conductive, binder-free substrate connection, making them promising catalysts for green hydrogen production. However, creating Mo-rich deposits is challenging, as the codeposition process typically favors Ni. Optimal deposition conditions for Mo-rich NiMo catalysts remain insufficiently explored. This article investigates Mo-rich NiMo electrodeposition from an ammonia-free citrate bath using NaSO4 as a chlorine-free support electrolyte. The effects of the deposition parameters, 1) sodium molybdate concentration in the electrolyte, 2) deposition current density, and 3) enhanced mass transport via working electrode rotation on the alkaline HER activity, were studied. The electrodeposits, containing 44-66 wt\% Mo, exhibited increased surface area due to a rough, cracked morphology and variable oxygen content of the catalyst. The oxygen content was linked to HER activity, revealing an inhibiting effect. The lowest overpotential of 118 mV at -10  mA cm-2 for the alkaline HER was achieved using an electrolyte with 0.02 mol L-1 sodium molybdate, a deposition current density of 600 mA cm-2, without electrode rotation. Respective samples combined a favorable Ni:Mo ratio comprising 56 wt\% Mo content with increased surface area and low oxygen content.}, language = {en} } @article{WirkertRothRostetal.2017, author = {Wirkert, Florian Josef and Roth, Jeffrey and Rost, Ulrich and Brodmann, Michael}, title = {Hydraulic cell compression for performance preserving upscaling of PEM electrolyzers}, series = {International Journal of Smart Grid and Clean Energy}, volume = {6}, journal = {International Journal of Smart Grid and Clean Energy}, number = {3}, issn = {2315-4462}, doi = {10.12720/sgce.6.3.171-176}, pages = {171 -- 176}, year = {2017}, abstract = {The technology of polymer electrolyte membrane (PEM) electrolysis provides an efficient way to produce hydrogen. In combination with renewable energy sources, it promises to be one of the key factors towards a carbon-free energy infrastructure in the future. Today, PEM electrolyzers with a power consumption higher than 1 MW and a gas output pressure of 30 bar (or even higher) are already commercially available. Nevertheless, fundamental research and development for an improved efficiency is far from being finally accomplished, and mostly takes place on a laboratory scale. Upscaling the laboratory prototypes to an industrial size usually cannot be achieved without facing further problems and/or losing efficiency. With our novel system design based on hydraulic cell compression, a lot of the commonly occurring problems like inhomogeneous temperature and current distribution can be avoided. In this study we present first results of an upscaling by a factor of 30 in active cell area.}, language = {en} } @inproceedings{Mutascu2016, author = {Mutascu, Cristian}, title = {Universitatea de Stiinte Aplicate Gelsenkirchen, Germania [Vorstellung des Westf{\"a}lischen Energieinstituts an der Westf{\"a}lischen Hochschule Gelsenkirchen]}, series = {Konferenz: Diaspora si prieteni sai 2016, 25.-28. April 2016 in Timisoara, Rum{\"a}nien}, booktitle = {Konferenz: Diaspora si prieteni sai 2016, 25.-28. April 2016 in Timisoara, Rum{\"a}nien}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-10185}, pages = {1 -- 23}, year = {2016}, abstract = {Kurz{\"u}bersicht der aktuellen Projekte des Westf{\"a}lischen Energieinstituts.}, language = {mul} } @inproceedings{PodleschnyMunteanRostetal.2016, author = {Podleschny, Pit Yannick and Muntean, Roxana and Rost, Ulrich and Brodmann, Michael}, title = {PEM Fuel Cells Electrodes Preparation Using Oxygen Plasma Treated Graphene Related Material Serving as Catalyst Support for Platinum Nanoparticles}, series = {Konferenz: NMWP Young Academics: Graphen und 2D-Materialien, 30.-31. August 2016 in Siegen}, booktitle = {Konferenz: NMWP Young Academics: Graphen und 2D-Materialien, 30.-31. August 2016 in Siegen}, year = {2016}, abstract = {This experimental work deals with the preparation and investigation of PEM fuel cell electrodes, which are obtained using Graphene Related Material (GRM) serving as catalyst support material for platinum nanoparticles. The applied GRM belong to the group of carbon nanofibers and exhibits a helical-ribbon structure with dimensions of 50 nm in diameter and an average length up to a few µm. Furthermore, utilized GRM provide a superior graphitisation degree of about 100 \%, which leads to both high corrosion resistance and low ohmic resistance. Material stability plays one of the main roles for long term fuel cell operation, whereby a great electrical catalyst contact combined with high specific surface area yields in high fuel cell performances. Prior to GRM dispersion and deposition onto a gas diffusion layer, the graphene structures are functionalized by oxygen plasma treatment. Through this step, functional oxygen groups are generated onto the GRM outer surface providing an improved hydrophilic behaviour and facilitating the GRM suspension preparation. In addition, the oxygen groups act as anchors for platinum nanoparticles which are subsequently deposited onto the GRM surface through a pulse electrodeposition process. Membrane electrode assemblies produced with the prepared electrodes are investigated in-situ in a PEM fuel cell test bench.}, language = {en} } @inproceedings{RostRothBrodmann2015, author = {Rost, Ulrich and Roth, Jeffrey and Brodmann, Michael}, title = {Ein neuartiges Konzept f{\"u}r Hochdruckelektrolyseursysteme in modularer Bauweise zur Produktion von Wasserstoff aus {\"U}berschussenergie erneuerbarer Quellen}, series = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, booktitle = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, editor = {Großmann, Uwe and Kunold, Ingo and Engels, Christoph}, publisher = {vwh, Verlag Werner H{\"u}lsbusch, Fachverlag f{\"u}r Medientechnik und -wirtschaft}, address = {Gl{\"u}ckstadt}, isbn = {978-3-86488-093-3}, pages = {99 -- 109}, year = {2015}, abstract = {F{\"u}r einen Energiesektor, der zuk{\"u}nftig im hohen Maße auf erneuerbaren Quellen beruht, sind Energiespeicher unverzichtbar, um die heute gewohnte Versorgungssicherheit auch in Zeiten geringer Einspeisung aus Wasser, PV- und/oder Windkraftanlagen garantieren zu k{\"o}nnen. Da konventionelle Speichertechnologien wie beispielsweise Pumpspeicherkraftwerke durch fehlende m{\"o}gliche Standorte in Deutschland nicht weiter ausgebaut werden, sind Alternativen notwendig. Es ist Konsens, hierf{\"u}r emissionsarme Strategien zu entwickeln, um die gesetzten Ziele zur Reduktion von CO2 Emissionen zu erreichen. Neben Batterien, die vorzugsweise f{\"u}r Kurzzeitspeicher einzusetzen sind, bietet sich Wasserstoff als umweltfreundlicher Sekund{\"a}renergietr{\"a}ger an, der in großen Mengen gespeichert und in Brennstoffzellen mit hohem Wirkungsgrad emissionsfrei in elektrische Energie umgewandelt werden kann. Da elementarer Wasserstoff nicht nat{\"u}rlich vorkommt, ist dieser zuvor zu generieren. {\"U}bersch{\"u}sse aus regenerativen Energiequellen k{\"o}nnen hierf{\"u}r ideal genutzt werden. In diesem Beitrag wird ein aussichtsreiches Konzept f{\"u}r einen modularen Hochdruckelektrolyseur vorgestellt, welcher erlaubt, Wasserstoff bei einem hohen Ausgangsdruck bereitzustellen. Durch den prinzipiellen Aufbau, ist ein beliebiges Druckniveau am Ausgang nur von der mechanischen Stabilit{\"a}t der verwendeten Bauteile abh{\"a}ngig. Hierdurch ist es m{\"o}glich, Wasserstoff direkt in einen Druckgasspeicher oder eine Pipeline zu produzieren, ohne einen zus{\"a}tzlichen Verdichter nutzen zu m{\"u}ssen. Dies resultiert in signifikanten Kosteneinsparungen und verbessert den Systemwirkungsgrad zuk{\"u}nftiger Anlagen entscheidend.}, language = {de} } @inproceedings{SagewkaRostRothetal.2015, author = {Sagewka, Christoph and Rost, Ulrich and Roth, Jeffrey and Brodmann, Michael}, title = {Entwicklung von vollmodularen PEM-Brennstoffzellen- und Elektrolyseursystemen mit segmentierten, planaren Polplatten}, series = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, booktitle = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, editor = {Großmann, Uwe and Kunold, Ingo and Engels, Christoph}, publisher = {vwh, Verlag Werner H{\"u}lsbusch, Fachverlag f{\"u}r Medientechnik und -wirtschaft}, address = {Gl{\"u}ckstadt}, isbn = {978-3-86488-093-3}, pages = {115 -- 121}, year = {2015}, abstract = {Im Rahmen der Energiewende ist eine Erweiterung der in das Verbund-netz integrierten Energiespeicher notwendig, um zuk{\"u}nftig die heute gewohnte Versorgungssicherheit trotz eines sehr hohen Anteils volatiler regenerativer Energieerzeugungsanlagen zu erm{\"o}glichen. Eine geeignete elektrochemische Methode zur umweltfreundlichen Zwischenspeicherung großer Energiemengen stellt die Wasserelektrolyse mit bedarfsorientierter R{\"u}ckverstromung dar. Dabei k{\"o}nnen die dynamischen Einspeise- und Last{\"a}nderungen im elektrischen Verbundnetz im besonderen Maße von Elektrolyseur- und Brennstoffzellen-systemen auf Basis von Polymer-Elektrolyt-Membranen (PEM) aufgefangen werden. Bestehende PEM-Systeme sind vor allem in ihrer konstruktiven Zellgr{\"o}ße und ihrer maximalen Leistung bei der Wasserstoffproduktion bzw. der Stromerzeugung stark begrenzt. Vor allem inhomogene Verpressungen großfl{\"a}chiger planarer Zellen in einem klassischen, mechanisch verspannten Stack f{\"u}hren zu hohen Leistungseinbußen. Zudem ergeben sich bei kleinen Stacks aufgrund der geringen Zellspannung ung{\"u}nstige Wandlungsverh{\"a}ltnisse zwischen Strom und Spannung f{\"u}r eine vor- bzw. nachgeschaltete Leistungselektronik. Ein neuartiges Stackkonzept mit segmentierten Polplatten bietet eine konstruktive L{\"o}sung f{\"u}r das Problem gr{\"o}ßerer aktiver Zellfl{\"a}chen und leistet einen Beitrag zur Entwicklung industriell einsetzbarer Hochdruckelektrolyseure und Brennstoffzellen.}, language = {de} } @inproceedings{RostRothBrodmann2015, author = {Rost, Ulrich and Roth, Jeffrey and Brodmann, Michael}, title = {Modular Polymer Electrolyte Membrane Fuel Cell and Electrolyser Stack Design with Hydraulic Compression}, series = {Power and Energy Student Summit(PESS) 2015, January 13th-14th, Dortmund Germany}, booktitle = {Power and Energy Student Summit(PESS) 2015, January 13th-14th, Dortmund Germany}, editor = {Kubis, Andreas and Rehtanz, Christian and Shapovalov, Anton and Hilbrich, Dominik and Plota, Ewa}, doi = {10.17877/DE290R-7265}, pages = {S02.4}, year = {2015}, abstract = {An energy economy with high share of renewable but volatile energy sources is dependent on storage strategies in order to ensure sufficient energy delivery in periods of e.g. low wind and/or low solar radiation. Hydrogen as environmental friendly energy carrier is thought to be an appropriate solution for large scale energy storage. In 2011 the NOW (national organisation for hydrogen in Germany) calculated the demand for hydrogen energy systems as positive (0.8 GW to 5.25 GW) and negative supply for varying power demand (0.68 to 4.3 GW) for the German energy economy in 2025. Due to its dynamic behaviour on load changes polymer electrolyte membrane fuel cells (PEMFC) as well as water electrolyser systems (PEMEL) can play a significant role for large scale hydrogen based storage systems. In this work a novel design concept for modular fuel cell and electrolyser stacks is presented with single cells in pockets surrounded by a hydraulic medium. This hydraulic medium introduces necessary compression forces on the membrane electrode assembly (MEA) of each cell within a stack. Furthermore, ideal stack cooling is achieved by this medium. Due to its modularity and scalability the modular stack design with hydraulic compression meets the requirements for large PEMFC as well as PEMEL units. Small scale prototypes presented in this work illustrate the potential of this design concept.}, language = {en} } @inproceedings{BrodmannRost2014, author = {Brodmann, Michael and Rost, Ulrich}, title = {A Modular Stack Technology for Electrochemical Cells Based on Hydraulic Compression}, series = {Konferenz: OZ-14, 7th German-Japanese Symposium on nanostructures, March 2-4, 2014 in Wenden/Olpe, Germany}, booktitle = {Konferenz: OZ-14, 7th German-Japanese Symposium on nanostructures, March 2-4, 2014 in Wenden/Olpe, Germany}, year = {2014}, abstract = {Membrane electrode assemblies (MEA) developed at the Westphalian Energy Institute for polymer electrolyte membrane fuel cells (PEMFC) are high tech systems containing various materials structured in nanoscale, at which electrochemical reactions occur on catalyst nano particle surfaces. For low reactance homogeneous compression of the MEA's layers is necessary. A novel stack architecture for electrochemical cells, especially PEMFC as well as PEM electrolysers, has been developed according to achieve ideal cell operation conditions. Single cells of such a stack are inserted into flexible slots that are surrounded by hydraulic media. While operation the hydraulic media is pressurised which leads to an even compression and cooling of the stack's cells. With this stack design it has been possible to construct a test facility for simultaneous characterisation of several MEA samples. As compression and temperature conditions of every single sample are equal, with the novel test system the effect of e.g. different electrode configurations can be investigated. Furthermore, the modular stack design leads to the development of hybrid energy applications combining fuel cells, electrolysers, batteries as well as metal hydride tanks in one system.}, language = {en} } @inproceedings{WirkertRothRostetal.2016, author = {Wirkert, Florian Josef and Roth, Jeffrey and Rost, Ulrich and Brodmann, Michael}, title = {A novel PEM electrolysis system with dynamic hydraulic compression for an optimized high-pressure operation}, series = {NEIS Conference 2016. Nachhaltige Energieversorgung und Integration von Speichern}, booktitle = {NEIS Conference 2016. Nachhaltige Energieversorgung und Integration von Speichern}, editor = {Schulz, Detlef}, edition = {1}, publisher = {Springer Vieweg}, address = {Wiesbaden}, isbn = {978-3-658-15028-0}, pages = {169 -- 174}, year = {2016}, abstract = {In this experimental work we present a novel electrolyzer system for the production of hydrogen and oxygen at high pressure levels without an additional mechanical compressor. Due to its control strategies, the operation conditions for this electrolyzer can be kept optimal for each load situation of the system. Furthermore, the novel system design allows for dynamic long-term operation as well as for easy maintainability. Therefore, the device meets the requirements for prospective power-to-gas applications, especially, in order to store excess energy from renewable sources. A laboratory scale device has been developed and high-pressure operation was validated. We also studied the long-term stability of the system by applying dynamic load cycles with load changes every 30 sec. After 80 h of operation the used membrane electrode assembly (MEA) was investigated by means of SEM, EDX and XRD analysis.}, language = {en} } @inproceedings{MutascuRostBrodmann2015, author = {Mutascu, Cristian and Rost, Ulrich and Brodmann, Michael}, title = {GeoFuelCells - Energieautarke Bohrlochsensorik mittels Brennstoffzellen}, series = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, booktitle = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, editor = {Großmann, Uwe and Kunold, Ingo and Engels, Christoph}, publisher = {vwh, Verlag Werner H{\"u}lsbusch, Fachverlag f{\"u}r Medientechnik und -wirtschaft}, address = {Gl{\"u}ckstadt}, isbn = {978-3-86488-093-3}, pages = {109 -- 115}, year = {2015}, abstract = {Im Rahmen eines gemeinsamen Forschungsprojekts mit dem Titel „Energieautarke Bohrlochsensorik mittels Brennstoffzellen - GeoFuelCells" wurde vom Geothermie-Zentrum Bochum und dem Westf{\"a}lischen Energieinstitut, unterst{\"u}tzt aus dem F{\"o}rderprogramm Ziel 2 (2007-2013 EFRE) des Landes NRW, ein brennstoffzellenbasiertes Energieversorgungssystem f{\"u}r Bohrloch-Anwendungen entwickelt.}, language = {de} } @inproceedings{BrodmannRost2017, author = {Brodmann, Michael and Rost, Ulrich}, title = {Batterien, Brennstoffzellen, Elektrolyseure - Forschung und Entwicklung an der Westf{\"a}lischen Hochschule}, series = {Konferenz: Batterietag NRW 2017, 28. M{\"a}rz 2017 in Aachen}, booktitle = {Konferenz: Batterietag NRW 2017, 28. M{\"a}rz 2017 in Aachen}, year = {2017}, language = {de} } @inproceedings{RostMargineanMunteanetal.2016, author = {Rost, Ulrich and Marginean, Gabriela and Muntean, Roxana and Podleschny, Pit Yannick and Brodmann, Michael and Merino, Cesar and Diez, Roberto}, title = {A cost-effective PEM fuel cell test system based on hydraulic compression with optimized platinum catalyst loading}, series = {International Energy and Sustainability Conference (IESC), June 30 - July 1, 2016}, booktitle = {International Energy and Sustainability Conference (IESC), June 30 - July 1, 2016}, editor = {International Energy and Sustainability Conference ,}, publisher = {IEEE}, address = {[Piscataway, NJ]}, isbn = {978-1-5090-2980-8}, doi = {10.1109/IESC.2016.7569500}, pages = {6}, year = {2016}, abstract = {For this study gas diffusion electrodes (GDE) with low platinum loading are prepared for the application as anode in polymer electrolyte membrane fuel cell (PEMFC) systems based on hydraulic compression. As catalyst support material, carbon nanofibers (CNF) are investigated because of their high specific surface area and high graphitization degree. The electrode preparation is optimized by an economic and environmental friendly pre-treatment process in oxygen plasma. For GDE manufacture an ink containing oxygen plasma activated CNFs as well as hydrophilic polymer is used. After spray coating of this CNF ink on a graphitic substrate, platinum is deposited using the pulse plating technique. Preliminary results showed a considerable improvement of CNF dispersibility as well as an increased amount and an optimized morphology of the deposited platinum. Morphology and microstructure are observed by scanning electron microscopy as well as transmission electron microscopy. Platinum loading is determined by thermogravimetric analysis to be in the range of 0.01 mg cm-2 to 0.017 mg cm-2. Furthermore, MEAs are prepared from these GDEs and testing is performed in a novel modular fuel cell test stack based on hydraulic compression. Technical information about stack design and functions is given in this work.}, language = {en} } @inproceedings{SchneiderRabanalArabach2025, author = {Schneider, Andreas and Rabanal-Arabach, Jorge}, title = {Shaalke: Development of a MATLAB Software Tool for Advanced Statistical Outdoor Data Evaluation}, series = {EU PVSEC 2025, 42nd European Photovoltaic Solar Energy Conference and Exhibition 22-26 September 2025, Bilbao, Spain. Conference Proceedings}, booktitle = {EU PVSEC 2025, 42nd European Photovoltaic Solar Energy Conference and Exhibition 22-26 September 2025, Bilbao, Spain. Conference Proceedings}, publisher = {WIP}, address = {M{\"u}nchen}, isbn = {3-936338-93-0}, issn = {2196-100X}, doi = {10.4229/EUPVSEC2025/3AV.3.11}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-48763}, pages = {020183-001 -- 020183-006}, year = {2025}, abstract = {This paper introduces Shaalke, a novel analytical software tool developed for the high-accuracy evaluation of long-term photovoltaic module measurement data. Addressing the critical need for robust parameter extraction from field data, Shaalke integrates advanced filtering, linear regression, and algorithmic processing to overcome limitations of traditional evaluation methods. We demonstrate Shaalke's capability to accurately determine STC parameters and both static and dynamic temperature coefficients, showing excellent agreement with manufacturer specifications and independent laboratory measurements. A key finding is Shaalke's precise mapping of the irradiance dependence of module efficiency, filling a significant gap left by typical datasheet values which often only provide data at 1000 and 200 W/m². Furthermore, the tool enables reliable power degradation analysis, identifying modules that exceed manufacturer-tolerated limits. Shaalke provides a comprehensive, data-driven platform for understanding real-world module performance, offering invaluable insights for system design, operation, and quality assurance, thereby bridging the gap between laboratory specifications and field performance.}, language = {en} } @article{RostMunteanPodleschnyetal.2016, author = {Rost, Ulrich and Muntean, Roxana and Podleschny, Pit Yannick and Marginean, Gabriela and Brodmann, Michael and Şerban, Viorel-Aurel}, title = {Influence of the Graphitisation Degree of Carbon Nano Fibres Serving as Support Material for Noble Metal Electro Catalysts on the Performance of PEM Fuel Cells}, series = {Solid state phenomena}, journal = {Solid state phenomena}, number = {254}, doi = {10.4028/www.scientific.net/SSP.254.27}, pages = {27 -- 32}, year = {2016}, abstract = {In this experimental work polymer electrolyte membrane fuel cell (PEMFC) electrodes are analysed, which are prepared by the use of two sorts of carbon nano fibres (CNF) serving as support material for platinum nano particles. Those CNFs, which are heat treated subsequently to their production, have a higher graphitisation degree than fibres as produced. The improved graphitisation degree leads to higher electrical conductivity, which is favourably for the use in PEMFC electrodes. Samples have been analysed, in order to determine graphitisation degree, electrical conductivity, as well as morphology and loading of the prepared electro catalyst. Membrane electrode assemblies manufactured from prepared electrodes are analysed in-situ in a PEM fuel cell test environment. It has been determined that power output for samples containing CNFs with higher graphitisation degree is increased by about 13.5\%.}, language = {en} } @inproceedings{MunteanPascalRostetal.2018, author = {Muntean, Roxana and Pascal, Dragos-Toader and Rost, Ulrich and Podleschny, Pit Yannick and Marginean, Gabriela and Schumacher, Marc}, title = {Studies on pulse electrodeposition of Pt-Ni binary alloy for electrochemical cell applications, 7th International Symposium on Advanced Materials and Structures}, series = {Konferenz: 7th International Conference on Advanced Materials and Structures (AMS 2018), 28.-31. M{\"a}rz 2018 in Timisoara (Rum{\"a}nien)}, booktitle = {Konferenz: 7th International Conference on Advanced Materials and Structures (AMS 2018), 28.-31. M{\"a}rz 2018 in Timisoara (Rum{\"a}nien)}, year = {2018}, language = {en} } @article{MunteanRostMargineanetal.2016, author = {Muntean, Roxana and Rost, Ulrich and Marginean, Gabriela and Vaszilcsin, Nicolae}, title = {Optimisation of the Electrodeposition Parameters for Platinum Nanoparticles on Carbon Nanofibers Support}, series = {Solid state phenomena}, journal = {Solid state phenomena}, number = {254}, doi = {10.4028/www.scientific.net/SSP.254.153}, pages = {153 -- 158}, year = {2016}, abstract = {Platinum nanoparticles electrodeposition on carbon nanofibers (CNF) support has been performed with the purpose to obtain electrodes that can be further used especially in a polymer electrolyte membrane fuel cell (PEMFC). A pretreatment of CNF is required in order to enhance the surface energy, which simultaneously improves handling and wettability as well as interaction with the platinum cations. This step was performed using oxygen plasma functionalization. To produce CNF supported Pt catalysts, an electrochemical method was applied and the deposition parameters were adjusted to obtain nanosized platinum particles with a good distribution onto the graphitic surface. The morphology and structure of the obtained particles were investigated by scanning electron microscopy combined with energy dispersive X-Ray spectroscopy. The amount of deposited platinum was established using thermogravimetrical measurements. Cyclic voltammetry performed in 0.5 M H2SO4 solution was applied for determining the electrochemical surface area (ECSA) of the obtained electrodes.The functionalization degree of the CNF outer surface has a strong influence on the structure, distribution and amount of platinum particles. Moreover, the current densities, which were set for the deposition process influenced not only the particles size but also the platinum amount. Applying an oxygen plasma treatment of 80 W for 1800 s, the necessary degree of surface functionalization is achieved in order to deposit the catalyst particles. The best electrodes were prepared using a current density of 50 mA cm-2 during the deposition process that leads to a homogenous platinum distribution with particles size under 80 nm and ECSA over 6 cm2}, language = {en} } @article{MunteanRostPascaletal.2016, author = {Muntean, Roxana and Rost, Ulrich and Pascal, Dragos-Toader and Marginean, Gabriela and Vaszilcsin, Nicolae}, title = {Determination of the Electrochemical Surface Area for CNF-Pt Electrocatalyst Using Cyclic Voltammetry}, series = {Chemical Bulletin of "Politehnica" University of Timisoara, Romania}, volume = {61 (75)}, journal = {Chemical Bulletin of "Politehnica" University of Timisoara, Romania}, number = {2}, pages = {44 -- 48}, year = {2016}, abstract = {Carbon Nanofibers (CNF) are considered to be a promising catalyst support material due to their unique characteristics, excellent mechanical, electrical and structural properties, high surface area and nevertheless, good interaction with metallic catalyst particles. The possibility of preparing CNF decorated with platinum by an electrochemical method was tested, using a hexachloroplatinic bath solution. The experiments were carried out with the aid of a Potentiostat/Galvanostat Ivium Technologies Vertex, in a three - electrode cell. The aim of the present work was to determine the electrochemical surface area (ECSA) of the CNF-Pt catalysts in relation to the functionalization treatment of fibers, using an electrochemical method. ECSA for different functionalized CNF-Pt catalysts was determined by cyclic voltammetry in 0.5 M H2SO4 solution. The highest active surface of platinum was obtained for the samples with CNF functionalized by plasma treatment using 80 W for 1800 s. The obtained results correlate very well with the particles size and distribution of platinum, revealed by scanning electron microscopy (SEM) and the quantity of deposited platinum determined by thermo gravimetrical analysis (TGA) respectively. Cyclic voltammetry (CV) has been proven to be a suitable method for estimation of the ECSA of the electrocatalysts.}, language = {en} } @inproceedings{RostBrodmannZekornetal.2016, author = {Rost, Ulrich and Brodmann, Michael and Zekorn, Bruno and Peinecke, Volker and Radev, Ivan and Podleschny, Pit Yannick}, title = {PEM fuel cell electrode preparation using oxygen plasma treated graphene related material serving as catalyst support for platinum nanoparticles}, series = {Konferenz: 7. NRW Nano-Konferenz, 7.-8. Dezember 2016 in M{\"u}nster}, booktitle = {Konferenz: 7. NRW Nano-Konferenz, 7.-8. Dezember 2016 in M{\"u}nster}, pages = {1}, year = {2016}, abstract = {This experimental work deals with the preparation and investigation of PEM fuel cell electrodes, which are obtained using Graphene Related Material (GRM) serving as catalyst support material for platinum nanoparticles. The applied GRM belong to the group of carbon nanofibers and exhibits a helical-ribbon structure with dimensions of 50 nm in diameter and an average length up to a few µm. Furthermore, utilized GRM provide a superior graphitisation degree of about 100 \%, which leads to both high corrosion resistance and low ohmic resistance. Material stability plays one of the main roles for long term fuel cell operation, whereby a great electrical catalyst contact combined with high specific surface area yields in high fuel cell performances. Prior to GRM dispersion and deposition onto a gas diffusion layer, the graphene structures are functionalized by oxygen plasma treatment. Through this step, functional oxygen groups are generated onto the GRM outer surface providing an improved hydrophilic behaviour and facilitating the GRM suspension preparation. In addition, the oxygen groups act as anchors for platinum nanoparticles which are subsequently deposited onto the GRM surface through a pulse electrodeposition process. Membrane electrode assemblies produced with the prepared electrodes are investigated in-situ in a PEM fuel cell test bench.}, language = {de} } @inproceedings{RostRigouMargineanetal.2014, author = {Rost, Ulrich and Rigou, Veronica and Marginean, Gabriela and Brodmann, Michael and Brandl, Waltraut}, title = {Oxygen Plasma Activated Carbon Nanofibres as Electrode Material for Proton Exchange Membrane Fuel Cells}, series = {Konferenz: Junior Euromat 2014: The Major Event for Young Materials Scientists, 21.-25. Juli 2014 in Lausanne (Schweiz)}, booktitle = {Konferenz: Junior Euromat 2014: The Major Event for Young Materials Scientists, 21.-25. Juli 2014 in Lausanne (Schweiz)}, pages = {1}, year = {2014}, abstract = {To further increase platinum utilisation in PEM fuel cells CNFs are investigated as catalyst support material due to the CNF's high specific surface area. Furthermore, CNFs provide suitable properties concerning corrosion resistance as well as electrical conductivity in contrast to conventional carbon supports. This work presents the results of an electrode preparation procedure based on O2 plasma activated CNFs. The plasma treatment leads to CNF dispersibility in alcohol/water for a spray coating process. Furthermore, O2 plasma activation enhances metal deposition on the CNF's surface. Pulse plating procedure as well as wet chemical metal synthesis have been used for particle deposition. For pulse plating a potentiostat/galvanostat type MMates 510 AC from Materials Mates, Italy has been used. Electrode morphology has been determined in SEM type XL 30 ESEM from Philips, The Netherlands.}, language = {en} } @article{MunteanPascalRostetal.2019, author = {Muntean, Roxana and Pascal, Dragos-Toader and Rost, Ulrich and Holtkotte, Lisa and N{\"a}ther, Johannes and K{\"o}ster, Frank and Underberg, Martin and H{\"u}lser, Tim and Brodmann, Michael}, title = {Investigation of Iridium Nanoparticles Supported on Sub-stoichiometric Titanium Oxides as Anodic Electrocatalysts in PEM Electrolysis. Part I.: Synthesis and Characterization}, series = {Topics in Catalysis}, volume = {62}, journal = {Topics in Catalysis}, number = {5-6}, issn = {1022-5528}, doi = {10.1007/s11244-019-01164-3}, pages = {429 -- 438}, year = {2019}, language = {en} } @article{MunteanPascalRostetal.2019, author = {Muntean, Roxana and Pascal, Dragos-Toader and Rost, Ulrich and Holtkotte, Lisa and N{\"a}ther, Johannes and K{\"o}ster, Frank and Underberg, Martin and H{\"u}lser, Tim and Brodmann, Michael}, title = {Investigation of Iridium Nanoparticles Supported on Sub-stoichiometric Titanium Oxides as Anodic Electrocatalysts in PEM Electrolysis. Part I.: Synthesis and Characterization}, series = {Topics in Catalysis}, volume = {62}, journal = {Topics in Catalysis}, number = {5/6}, issn = {1022-5528}, doi = {10.1007/s11244-019-01164-3}, pages = {429 -- 438}, year = {2019}, language = {en} } @inproceedings{MunteanRostMargineanetal.2015, author = {Muntean, Roxana and Rost, Ulrich and Marginean, Gabriela and Vaszilcsin, Nicolae}, title = {Determination of the electrochemical surface area for CNTs-PT electro catalyst using cyclic voltammetry}, series = {Konferenz: BraMat 2015, 9th International Conference on Materials Science \& Engineering, March 5-7, 2015. Book of Abstracts}, booktitle = {Konferenz: BraMat 2015, 9th International Conference on Materials Science \& Engineering, March 5-7, 2015. Book of Abstracts}, editor = {Transilvania University of Brasov - Romania. Faculty of Materials Science and Engineering,}, publisher = {Transilvania University of Brasov - Romania}, address = {Brasov}, pages = {170}, year = {2015}, abstract = {Platinum is one of the most effective electro catalysts for PEMFCs (proton exchange membrane fuel cells), but because of its prohibitive price, the use of this metal in industrial purposes is limited. As a consequence, during last years, several materials have been investigated, in order to obtain an efficient catalyst for both ORR (oxygen reduction reaction) and HOR (hydrogen oxidation reaction), which can replace the expensive platinum but preserving the same properties: high electrical conductivity, structural stability and good corrosion resistance. Moreover, one of the most important parameters for catalyst materials is the electrochemical surface area (real surface area), which has a strong influence on the reaction rate and also on the current density. CNFs (carbon nanofibers) are considered to be a promising catalyst support material due to their unique characteristics, excellent mechanical, electrical and structural properties, high surface area and nevertheless, good interaction with platinum particles. The possibility of preparing CNFs decorated with platinum by electrochemical methods was tested, using a hexachloroplatinic solution bath. The experiments were carried out with the aid of a Potentiostat/Galvanostat MMate 510, in a three - electrode cell. The aim of the present work was to determine the electrochemical surface area of the CNFs - Pt catalysts, using an electrochemical method. The obtained results correlate very well with the particles size and distribution of platinum, analyzed by SEM (scanning electron microscopy) respectively with the quantity of deposited platinum determined by TG (thermo gravimetrical analyses). Cyclic voltammetry is a suitable method for estimation of the real surface area for catalyst particles.}, language = {en} } @inproceedings{RostMunteanPodleschnyetal.2015, author = {Rost, Ulrich and Muntean, Roxana and Podleschny, Pit Yannick and Marginean, Gabriela and Brodmann, Michael and Şerban, Viorel-Aurel}, title = {Investigation of the Influence of Graphitisation Degree of Carbon Nano Fibres Serving as Catalyst Support Material for Noble Metal Electro Catalysts on the Performance of PEM Fuel Cells}, series = {Sixth International Conference on Advanced Materials and Structures. 16-17 October 2015, Timisoara, Romania}, booktitle = {Sixth International Conference on Advanced Materials and Structures. 16-17 October 2015, Timisoara, Romania}, editor = {Politehnica University of Timisoara,}, publisher = {Editura Politehnica}, address = {Timișoara}, pages = {6}, year = {2015}, abstract = {In polymer electrolyte membrane fuel cells (PEMFC) noble metal nano particles are deposited on graphitic supports serving as electrocatalysts for devices with high power density. In this study anodes are analysed with low platinum loading of about 0.1 mg cm-2. These electrodes are prepared by carbon nano fibres (CNF) decorated with platinum nano particles. For electrode manufacturing two sorts of fibres, which are produced in an industrial scale, are used with different graphitisation degree and surface area. CNF layers are applied on commercially available graphitic substrate by spray coating which leads to a porous structure with high surface area. Subsequently, platinum deposition is achieved by pulsed electroplating for an improved platinum utilisation in PEMFC electrodes. Spray coating and platinum deposition are assisted by a previous oxygen plasma activation process. Prepared anode material is characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), X-ray fluorescence spectroscopy (XRF) and thermogravimetry (TGA). Electrochemical analyses (cyclic voltammetry and corrosion test) are carried out in 0.5 M sulphuric acid. The effect of graphitisation degree of carbon nano fibres on the performance of prepared electrodes is investigated in-situ in a PEM fuel cell test bench.}, language = {en} } @inproceedings{RostMunteanMargineanetal.2015, author = {Rost, Ulrich and Muntean, Roxana and Marginean, Gabriela and Vaszilcsin, Nicolae and Brodmann, Michael}, title = {Effect of the Process Parameters for Oxygen Plasma Activation of Carbon Nanofibres on the Characteristics of Deposited Platinum Catalyst Nanoparticles}, series = {Konferenz: The Annual World Conference on Carbon, 12.-17. Juli 2015 in Dresden}, booktitle = {Konferenz: The Annual World Conference on Carbon, 12.-17. Juli 2015 in Dresden}, pages = {1}, year = {2015}, abstract = {In state of the art polymer electrolyte membrane fuel cells (PEMFC) rare and expensive platinum group metals (PGM) are used as catalyst material. Reduction of PGM in PEMFC electrodes is strongly required to reach cost targets for this technology. An optimal catalyst utilisation is achieved in the case of nano-structured particles supported on carbon material with a large specific surface area. In this study, graphitic material in form of carbon nanofibres (CNFs) is decorated with platinum (Pt) particles serving as catalyst material for PEMFC electrodes with low Pt loading. For electrode preparation CNFs have been previously activated by means of radio frequency induced oxygen plasma. This kind of treatment results in formation of functional groups on the CNF's surface which directly influences the characteristics of subsequent Pt particle deposition. Different plasma parameters (plasma power, gas flow or exposure time) have to be set in order to achieve formation of oxygen containing functional groups (hydroxylic, carboxylic or carbonylic) on the CNF's surface. In the frame of this experimental work, electrodes are investigated in respect of optimal morphology, microstructure as well as electrochemical properties. Therefore, samples were characterised by means of scanning electron microscopy combined with energy dispersive X-ray analysis, transmission electron microscopy, thermogravimetry, X-ray diffraction, X-ray fluorescence as well as polarisation measurements.}, language = {en} } @article{RostMutascuRothetal.2015, author = {Rost, Ulrich and Mutascu, Cristian and Roth, Jeffrey and Sagewka, Christoph and Brodmann, Michael}, title = {Proof of Concept of a Novel PEM Fuel Cell Stack Design with Hydraulic Compression}, series = {Journal of Energy and Power Engineering}, volume = {9}, journal = {Journal of Energy and Power Engineering}, number = {9}, doi = {10.17265/1934-8975/2015.09.003}, pages = {775 -- 783}, year = {2015}, abstract = {In this study, a novel design concept for PEMFC (polymer electrolytemembrane fuel cell) stacks is presented with singlecells inserted in pockets surrounded by a hydraulic medium. Thehydraulic pressure introduces necessary compression forces to themembrane electrode assembly of each cell within a stack. Moreover, homogeneous cell cooling is achieved by this medium. First,prototypes presented in this work indicate that, upscaling of cells for the novelstack design is possible without significantperformancelosses. Due to its modularity and scalability, this stackdesign meets the requirements for large PEMFC units.}, subject = {Polymer-Elektrolytmembran-Brennstoffzelle}, language = {en} } @inproceedings{RigouRostMargineanetal.2013, author = {Rigou, Veronica and Rost, Ulrich and Marginean, Gabriela and Brodmann, Michael and Brandl, Waltraut}, title = {Oxygen Plasma Activated Carbon Nanotubes as Electrode Material for Proton Exchange Membrane Fuel Cells}, series = {Konferenz: "2nd International Conference on Materials for Energy", 12.-16. Mai 2013 in Karlsruhe}, booktitle = {Konferenz: "2nd International Conference on Materials for Energy", 12.-16. Mai 2013 in Karlsruhe}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-7123}, pages = {1}, year = {2013}, abstract = {Since the 1980's, against the backdrop of global warming and the decline of conventional energy resources, low emission and renewable energy systems have gotten into the focus of politics as well as research and development. In order to decrease the emission of greenhouse gases Germany intents to generate 80\% of its electrical energy from renewable and low emission sources by 2050. For low emission electricity generation hydrogen operated fuel cells are a potential solution. However, although fuel cell technology has been well known since the 19th century cost effective materials are needed to achieve a breakthrough in the market. Proton Exchange Membrane Fuel Cells with Carbon Nanotubes as Electrode Material At the Westphalian Energy Institute of the Wesphalian University of Applied Sciences one main focus is on the research of proton exchange membrane fuel cells (PEMFC). PEMFC membrane electrode assemblies (MEA) consist of a polymer membrane with electrolytic properties covered on both sides by a catalyst layer (CL) as well as a porous and electrical conductive gas diffusion layer (GDL). For PEMFC carbon nanotubes (CNT) have ideal properties as electrode material concerning electrical conductivity, oxidation resistance and media transport. CNTs are suitable for the use as catalyst support material within the CL due to their large surface in comparison to conventional carbon supports. Furthermore, oxygen plasma treated CNTs show electrochemical activity referred to hydrogen adsorption and desorption, which has been shown by cyclic voltammetry in 0.5 M sulfuric acid solution. According to the PEMFCs anode a GDL coated with oxygen plasma activated CNTs has promising properties to significantly reduce catalyst content (e.g. platinum) of the anodic CL.}, subject = {Polymer-Elektrolytmembran-Brennstoffzelle}, language = {en} } @inproceedings{RostBrandlBrodmannetal.2014, author = {Rost, Ulrich and Brandl, Waltraut and Brodmann, Michael and Marginean, Gabriela and Rigou, Veronica}, title = {Development of Membrane Electrode Assemblies Based on Oxygen Plasma Activated Carbon Nanotubes and their Application in a Novel Modular Test System with Hydraulic Compression}, series = {Konferenz: 14th Ulm Electrochemical Talks (UECT), 23.-26.06.2014 in Ulm}, booktitle = {Konferenz: 14th Ulm Electrochemical Talks (UECT), 23.-26.06.2014 in Ulm}, year = {2014}, abstract = {The membrane electrode assemblies (MEA) for polymer electrolyte membrane fuel cells (PEMFC) developed at the Westphalian Energy Institute are based on oxygen plasma activated carbon nanotubes (CNT) doped with platinum particles. For electrode preparation an ink is used containing the activated CNTs as well as hydrophobic and hydrophilic material in solved form. After this ink is sprayed onto a graphitic substrate platinum particles are deposited by pulse plating method, where the plasma activation enhances CNT dispersibility as well as platinum deposition. This materials mixture is structured in nanoscale with the aim to increase the catalyst particles' specific surface. For low reactance at operation, homogeneous compression of the MEA's layers is necessary within a PEMFC. A novel stack architecture for electrochemical cells, especially PEMFC as well as PEM electrolysers, has been developed in order to achieve ideal cell operation conditions. Single cells of such a stack are inserted into flexible slots that are surrounded by a hydraulic medium which is pressurised during operation in order to achieve an even compression and cooling of the stack's cells. With this stack design it has been possible to construct a test facility for simultaneous characterisation of several MEA samples. As compression and temperature conditions of every single sample are the same, the effects of e.g. different electrode configurations can be investigated with the novel test system.}, language = {en} } @article{RostBrodmannŞerbanetal.2012, author = {Rost, Ulrich and Brodmann, Michael and Şerban, Viorel-Aurel and Mutascu, Cristian and Roth, Jeffrey and Zekorn, Bruno}, title = {State of the Art of PEM Fuel Cells with a Focus on a Modular Fuel Cell Stack with Hydraulic Compression}, series = {Scientific bulletin of the "politehnica" university of Timisoara, Romania. Transactions on mechanics}, volume = {57 (71)}, journal = {Scientific bulletin of the "politehnica" university of Timisoara, Romania. Transactions on mechanics}, number = {2}, pages = {1 -- 6}, year = {2012}, abstract = {This report gives a brief overview to the state of the art of PEM fuel cell technology and a description of a newly developed fuel cell stack concept. One main research activity at the Westphalian Energy Institute of the Westphalian University of Applied Sciences is the development of PEM fuel cells, for which a range of different materials have been investigated for fuel cell pole plate construction. Whereas graphite is a material which has suitable properties concerning conductivity as well as manufacturing e.g. for milling, stainless steel foils are suitable for economical hydroforming processes. However, with steel coating is necessary to increase corrosion resistance as well as electrical conductivity. A new fuel cell stack design is currently under development using separated single fuel cells with hydraulic cell compression. The advantages of this stack concept are modularity, effective heat exchanging and constant, uniform cell compression which are further described in this work.}, subject = {Polymer-Elektrolytmembran-Brennstoffzelle}, language = {en} } @book{BontrupMarquardt2015, author = {Bontrup, Heinz-Josef and Marquardt, Ralf-Michael}, title = {Die Zukunft der großen Energieversorger}, editor = {Bontrup, Heinz-Josef and Marquardt, Ralf-Michael}, publisher = {UVK Verlag}, address = {T{\"u}bingen}, isbn = {978-3-86496-865-5}, publisher = {Westf{\"a}lische Hochschule Gelsenkirchen Bocholt Recklinghausen}, pages = {278}, year = {2015}, subject = {Energieversorgungsunternehmen}, language = {de} } @article{RostWirkertRothetal.2022, author = {Rost, Ulrich and Wirkert, Florian Josef and Roth, Jeffrey and Brodmann, Michael and Stiber, Svenja and Saul Gago, Aldo and Friedrich, Kaspar Andreas}, title = {A novel advanced test system for polymer electrolyte membrane water electrolysis based on hydraulic cell compression}, series = {Fuel Cells, Band 22, Ausgabe 6}, journal = {Fuel Cells, Band 22, Ausgabe 6}, doi = {10.1002/fuce.202200068}, pages = {284 -- 289}, year = {2022}, abstract = {In this work, a novel polymer electrolyte membrane water electrolyzer (PEMWE) test cell based on hydraulic single-cell compression is described. In this test cell, the current density distribution is almost homogeneous over the active cell area due to hydraulic cell clamping. As the hydraulic medium entirely surrounds the active cell components, it is also used to control cell temperature resulting in even temperature distribution. The PEMWE single-cell test system based on hydraulic compression offers a 25 cm2 active surface area (5.0 × 5.0 cm) and can be operated up to 80°C and 6.0 A/cm2. Construction details and material selection for the designed test cell are given in this document. Furthermore, findings related to pressure distribution analyzed by utilizing a pressure-sensitive foil, the cell performance indicated by polarization curves, and the reproducibility of results are described. Experimental data indicate the applicability of the presented testing device for relevant PEMWE component testing and material analysis.}, language = {en} } @incollection{RostWirkertBrodmann2017, author = {Rost, Ulrich and Wirkert, Florian Josef and Brodmann, Michael}, title = {A novel PEM Electrolysis System with Dynamic Hydraulic Compression for an Optimized High-pressure Operation}, series = {Nachhaltige Energieversorgung und Integration von Speichern. NEIS Conference 2016 = Sustainable energy supply and energy storage systems}, booktitle = {Nachhaltige Energieversorgung und Integration von Speichern. NEIS Conference 2016 = Sustainable energy supply and energy storage systems}, editor = {Schulz, Detlef}, publisher = {Springer}, address = {Wiesbaden}, isbn = {978-3-658-15028-0}, doi = {10.1007/978-3-658-15029-7}, publisher = {Westf{\"a}lische Hochschule Gelsenkirchen Bocholt Recklinghausen}, pages = {169 -- 174}, year = {2017}, language = {en} } @article{LoefflerZellmerSchneideretal.2023, author = {L{\"o}ffler, Markus Jan and Zellmer, Florian and Schneider, Markus and Kreischer, Christian}, title = {A Multiphase Rail Launcher With Circular Geometry and Modular Design: Development, Construction, and First Experiments}, series = {IEEE Transactions on Plasma Science}, volume = {2023}, journal = {IEEE Transactions on Plasma Science}, number = {2023-03}, doi = {10.1109/TPS.2023.3240773}, year = {2023}, language = {en} } @book{Bontrup2021, author = {Bontrup, Heinz-Josef}, title = {Arbeit, Kapital und Staat, Pl{\"a}doyer f{\"u}r eine demokratische Wirtschaft}, editor = {Bontrup, Heinz-Josef}, publisher = {PapyRossa Verlag}, address = {K{\"o}ln}, isbn = {978-3-89438-326-8}, publisher = {Westf{\"a}lische Hochschule Gelsenkirchen Bocholt Recklinghausen}, pages = {750}, year = {2021}, subject = {Arbeit, Kapital und Staat}, language = {de} } @inproceedings{LoefflerMeckingLindenblattetal.2016, author = {L{\"o}ffler, Markus Jan and Mecking, Klaus and Lindenblatt, Tobias and Schneider, Markus}, title = {Thermal Stress at the Surface of Thick Conductive Plates Induced by Sinusoidal Current Pulses}, year = {2016}, language = {en} } @article{LoefflerRochHundertmarketal.2015, author = {L{\"o}ffler, Markus Jan and Roch, Martin and Hundertmark, Stephan and Zacharias, Peter}, title = {The Modular Augmented Staged Electromagnetic Launcher Operated in the Energy Storage Mode}, series = {IEEE Transactions on Plasma Science}, volume = {2015}, journal = {IEEE Transactions on Plasma Science}, number = {Vol. 43, Issue: 5}, year = {2015}, language = {en} } @techreport{Loeffler2025, type = {Working Paper}, author = {L{\"o}ffler, Markus Jan}, title = {Dynamische Stromtarife zur Regelung EE-versorgten Stromverbrauchs : eine Analyse am Beispiel des Stromverbrauchs im Jahr 2024}, edition = {Version 1.2}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-48063}, pages = {60}, year = {2025}, abstract = {Zusammenfassung Anlass dieser Studie ist die verpflichtende Einf{\"u}hrung dynamischer Stromtarife gem{\"a}ß \S41 EnWG. Hierdurch soll ein Paradigmenwechsel im Hinblick auf den Stromverbrauch bewirkt werden: Der Stromverbrauch soll sich k{\"u}nftig bestm{\"o}glich an das {\"u}berwiegend wettergef{\"u}hrte Stromangebot der Erneuerbare-Energien-Quellen anpassen, statt dass sich das Stromangebot wie bisher am Strombedarf orientiert. Die Studie untersucht, inwieweit dynamische Stromtarife das Stromverbraucher-Verhalten und die Gesamtstromkosten des Jahres 2024 h{\"a}tten beeinflussen k{\"o}nnen, wenn diese bereits 2024 deutschlandweit genutzt worden w{\"a}ren.}, language = {de} } @article{KellenbergerVaszilcsinDucaetal.2022, author = {Kellenberger, Andrea and Vaszilcsin, Nicolae and Duca, Delia and Dan, Mircea Laurentiu and Duteanu, Narcis and Stiber, Svenja and Morawietz, Tobias and Biswas, Indro and Ansar, Syed Asif and Gazdzicki, Pawel and Wirkert, Florian Josef and Roth, Jeffrey and Rost, Ulrich and Brodmann, Michael and Saul Gago, Aldo and Friedrich, Kaspar Andreas}, title = {Towards Replacing Titanium with Copper in the Bipolar Plates for Proton Exchange Membrane Water Electrolysis}, series = {Materials 2022, 15(5), 1628}, journal = {Materials 2022, 15(5), 1628}, doi = {10.3390/ma15051628}, year = {2022}, abstract = {For proton exchange membrane water electrolysis (PEMWE) to become competitive, the cost of stack components, such as bipolar plates (BPP), needs to be reduced. This can be achieved by using coated low-cost materials, such as copper as alternative to titanium. Herein we report on highly corrosion-resistant copper BPP coated with niobium. All investigated samples showed excellent corrosion resistance properties, with corrosion currents lower than 0.1 µA cm-2 in a simulated PEM electrolyzer environment at two different pH values. The physico-chemical properties of the Nb coatings are thoroughly characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). A 30 µm thick Nb coating fully protects the Cu against corrosion due to the formation of a passive oxide layer on its surface, predominantly composed of Nb2O5. The thickness of the passive oxide layer determined by both EIS and XPS is in the range of 10 nm. The results reported here demonstrate the effectiveness of Nb for protecting Cu against corrosion, opening the possibility to use it for the manufacturing of BPP for PEMWE. The latter was confirmed by its successful implementation in a single cell PEMWE based on hydraulic compression technology.}, language = {en} } @article{CieluchPodleschnyKazameretal.2022, author = {Cieluch, Maximilian and Podleschny, Pit Yannick and Kazamer, Norbert and Wirkert, Florian Josef and Rost, Ulrich and Brodmann, Michael}, title = {Development of a Bifunctional Ti-Based Gas Diffusion Electrode for ORR and OER by One- and Two-Step Pt-Ir Electrodeposition}, series = {nanomaterials 2022, 12 (/), 1233}, journal = {nanomaterials 2022, 12 (/), 1233}, doi = {10.3390/nano12071233}, year = {2022}, abstract = {The present paper presents one- and two-step approaches for electrochemical Pt and Ir deposition on a porous Ti-substrate to obtain a bifunctional oxygen electrode. Surface pre-treatment of the fiber-based Ti-substrate with oxalic acid provides an alternative to plasma treatment for partially stripping TiO2 from the electrode surface and roughening the topography. Electrochemical catalyst deposition performed directly onto the pretreated Ti-substrates bypasses unnecessary preparation and processing of catalyst support structures. A single Pt constant potential deposition (CPD), directly followed by pulsed electrodeposition (PED), created nanosized noble agglomerates. Subsequently, Ir was deposited via PED onto the Pt sub-structure to obtain a successively deposited PtIr catalyst layer. For the co-deposition of PtIr, a binary PtIr-alloy electrolyte was used applying PED. Micrographically, areal micro- and nano-scaled Pt sub-structure were observed, supplemented by homogenously distributed, nanosized Ir agglomerates for the successive PtIr deposition. In contrast, the PtIr co-deposition led to spherical, nanosized PtIr agglomerates. The electrochemical ORR and OER activity showed increased hydrogen desorption peaks for the Pt-deposited substrate, as well as broadening and flattening of the hydrogen desorption peaks for PtIr deposited substrates. The anodic kinetic parameters for the prepared electrodes were found to be higher than those of a polished Ir-disc.}, language = {en} } @inproceedings{BoehmThielkerKazameretal.2022, author = {B{\"o}hm, Leonard and Thielker, Klaus and Kazamer, Norbert and Wirkert, Florian Josef and Marginean, Gabriela and Rost, Ulrich and Apfel, Ulf-Peter and Brodmann, Michael}, title = {Electrodeposition of a Ni-Mo alloy Catalyst with Optimized Mo-Content for Hydrogen Evolution Reaction in AEM-Electrolysis}, series = {WHEC-2022, 23rd World Hydrogen Energy Conference}, booktitle = {WHEC-2022, 23rd World Hydrogen Energy Conference}, year = {2022}, abstract = {Various aqueous citrate electrolyte compositions for the Ni-Mo electrodeposition are explored in order to deposit Ni-Mo alloys with Mo-content ranging from 40 wt\% to 65 wt\% to find an alloy composition with superior catalytic activity towards the hydrogen evolution reaction (HER). The depositions were performed on copper substrates mounted onto a rotating disc electrode (RDE) and were investigated via scanning electron microscopy (SEM), X-ray fluorescence (XRF) and X-ray diffraction (XRD) methods as well as linear sweep voltammetry (LSV) and impedance spectroscopy. Kinetic parameters were calculated via Tafel analysis. Partial deposition current densities and current efficiencies were determined by correlating XRF measurements with gravimetric results. The variation of the electrolyte composition and deposition parameters enabled the deposition of alloys with Mo-content over the range of 40-65 wt\%. An increase in Mo-content in deposited alloys was recorded with an increase in rotation speed of the RDE. Current efficiency of the deposition was in the magnitude of <1\%, which is characteristic for the deposition of alloys with high Mo-content. The calculated kinetic parameters were used to determine the Mo-content with the highest catalytic activity for use in the HER.}, language = {en} } @article{CieluchKazamerBoehmetal.2024, author = {Cieluch, Maximilian and Kazamer, Norbert and B{\"o}hm, Leonard and Sanden, Sebastian and Zerebecki, Swen and Wirkert, Florian Josef and Apfel, Ulf-Peter and Brodmann, Michael}, title = {Effect of Electrolyte pH in Additive-Free NiFe Catalyst Electrodeposition for Electro-Catalytic OER Applications}, series = {ChemElectroChem}, volume = {(11) 2024}, journal = {ChemElectroChem}, number = {Issue 23}, doi = {10.1002/celc.202400492}, pages = {11}, year = {2024}, abstract = {This study presents the correlation between electrolyte pH, surface morphology, chemical speciation and electro-catalytic oxygen evolution activity of additive-free electrodeposited NiFe catalysts for application in anion exchange membrane water electrolysis. Spherical morphologies were identified at pH 0, shifting towards honey-combed structures at pH 4 with increasing surface area, especially at pH 3. Further, the electrolyte pH was found to influence the NiFe composition and electro-catalytic activity. Enhanced OER activity was noted at pH 2 with overpotentials of 214 mV at 10 mA cm-2 and 267 mV at 100 mA cm-2. The results reveal that the electrolyte pH is a parameter not only influencing the morphology but also tailoring the surface area, Fe oxide and Fe hydroxide composition and consequently the catalytic activity. Further, the outcomes highlight the electrolyte pH as a key process parameter that should be adjusted according to the application, and may substitute the addition of electrolyte-additives, proposing a simpler method for improving catalyst electrodeposition.}, language = {en} } @article{CieluchDueerkopKazameretal.2024, author = {Cieluch, Maximilian and D{\"u}erkop, Dennis and Kazamer, Norbert and Wirkert, Florian Josef and Podleschny, Pit Yannick and Rost, Ulrich and Schmiemann, Achim and Brodmann, Michael}, title = {Manufacturing and investigation of MEAs for PEMWE based on glass fibre reinforced PFSA/ssPS composite membranes and catalyst-coated substrates prepared via catalyst electrodeposition}, series = {International Journal of Hydrogen Energy}, volume = {52}, journal = {International Journal of Hydrogen Energy}, doi = {10.1016/j.ijhydene.2023.07.310}, pages = {521 -- 533}, year = {2024}, abstract = {Since high costs restrict the wide-range implementation of green hydrogen production capacities based on proton exchange membrane water electrolysis (PEMWE), efforts on cost reduced components need to be made. Beside the necessary noble metal catalyst, the membrane material is a main cost driver. In this work, a novel glass fibre reinforced PFSA/ssPS composite membrane is investigated as an alternative to widely used Nafion®. These membranes are processed into membrane-electrode-assemblies (MEAs) in conjunction with catalyst-coated substrates, prepared via electrochemical catalyst deposition. This approach is promising to reduce costs due to less expensive raw materials and due to increasing catalyst utilization by graded catalyst layers. Characterisation of the components and entire MEAs was performed ex-situ as well as in-situ via PEMWE operation.}, language = {en} } @article{LoefflerZellmerSchneideretal.2024, author = {L{\"o}ffler, Markus Jan and Zellmer, Florian and Schneider, Markus and Kreischer, Christian}, title = {An Augmented Multiphase Rail Launcher With a Modular Design: Extended Setup and Muzzle Fed Operation}, series = {IEEE Transactions on Plasma Science}, volume = {2024}, journal = {IEEE Transactions on Plasma Science}, doi = {10.1109/TPS.2024.3374461}, year = {2024}, language = {en} } @article{LoefflerZellmer2023, author = {L{\"o}ffler, Markus Jan and Zellmer, Florian}, title = {Augmented Three-Phase AC-Railgun: Basic Considerations}, series = {IEEE Transactions on Plasma Science}, volume = {2023-01}, journal = {IEEE Transactions on Plasma Science}, number = {01}, doi = {10.1109/TPS.2022.3229569}, year = {2023}, language = {en} } @phdthesis{Podleschny2021, author = {Podleschny, Pit Yannick}, title = {Investigation of the saving potential of noble catalyst material in polymer electrolyte membrane fuel cells}, school = {Westf{\"a}lische Hochschule Gelsenkirchen Bocholt Recklinghausen}, pages = {181}, year = {2021}, abstract = {The energy transition towards renewable energies for the overall energy supply (electricity, heat, mobility, etc.) is already well advanced and the further expansion is planned. The volatility of renewable energies is being addressed by the hydrogen technology. However, there is still a need for optimization of the cost-efficient reconversion of stored energy in the form of hydrogen, e.g. in applications for decarbonization of the power grid or of the mobility sector. For instance, the cost of an automotive low-temperature polymer electrolyte membrane fuel cell (PEMFC) must be lowered by reducing the platinum loading and the lifetime must be further improved to achieve the competitiveness of this technology. The aim of the present thesis was to develop membrane electrode assemblies (MEAs) with ultra-low platinum loading, high performance and increased lifetime for the use in PEMFCs. They are fabricated by an innovative MEA preparation process based on the pulse electrodeposition of platinum (Pt) using carbon nanofibers (CNFs) as a catalyst support with enhanced resistance to carbon oxidation reaction. The design of the MEA preparation process and the development of ultra-low Pt-loaded anodes and cathodes was the starting point of this thesis. It was found that the Pt/CNF catalyst used on the anode side had better characteristics than a commercial Pt/C catalyst, since the same power output of 0.525 W cm-2 was obtained with 10 .....}, language = {en} } @article{Marquardt2024, author = {Marquardt, Ralf-Michael}, title = {Gesamtwirtschaftliche Finanzierungsproblematik der Energiewende}, series = {VIK Mitteilungen}, journal = {VIK Mitteilungen}, number = {3}, pages = {26 -- 29}, year = {2024}, abstract = {Finanzierungsmodelle f{\"u}r Transformationsprojekte der Energiewende}, language = {de} } @article{RostPodleschnySchumacheretal.2018, author = {Rost, Ulrich and Podleschny, Pit Yannick and Schumacher, Marc and Muntean, Roxana and Pascal, Dragos-Toader and Mutascu, Cristian and Koziolek, J. and Marginean, Gabriela and Brodmann, Michael}, title = {Long-term Stable Electrodes Based on Platinum Electrocatalysts Supported on Titanium Sintered Felt for the Use in PEM Fuel Cells}, series = {IOP conference series. Materials science and engineering}, journal = {IOP conference series. Materials science and engineering}, number = {416}, issn = {1757-8981}, doi = {10.1088/1757-899X/416/1/012013}, pages = {012013}, year = {2018}, language = {en} }