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Mölmen, L., Fast, L., Lundblad, A. O., Eriksson, P. & Leisner, P. (2023). Contact resistance measurement methods for PEM fuel cell bipolar plates and power terminals. Journal of Power Sources, 555, Article ID 232341.
Open this publication in new window or tab >>Contact resistance measurement methods for PEM fuel cell bipolar plates and power terminals
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2023 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 555, article id 232341Article in journal (Refereed) Published
Abstract [en]

The electrical contact resistance is a key parameter for optimising both the bipolar plate of the polymer electrolyte membrane fuel cell (PEMFC) and the electrical contact of the power terminal of the stack. The contact resistance is affected by the conductivity, roughness, and hardness of the two contacting surfaces. Here, new, application-specific contact resistance measurement methods are proposed for both the stack power terminal, and the bipolar plate. The proposed methods are compared to methods from references as well as standards, and it is concluded that the uncertainty of the measurements can be reduced by changing the measurement setup, and that the influence of probe resistance on measurement results can be eliminated. Furthermore, the effect of different accelerated durability tests on the contact resistance of the power terminal is examined both on test coupons and on a prototype screw connection with an electroless NiP and an electroplated NiSn coatings. As expected, the NiSn coupons gives lower contact resistance after ageing as compared to the NiP. However, the increase in contact resistance seen on coupons after ageing is not observed on the prototype screw connection. © 2022 The Author(s)

Place, publisher, year, edition, pages
Elsevier B.V., 2023
Keywords
Aluminium, Electrical contact resistance, GDL, NiP, NiSn, PEMFC, Binary alloys, Current voltage characteristics, Durability, Electric contacts, Electric resistance measurement, Polyelectrolytes, Proton exchange membrane fuel cells (PEMFC), Screws, Uncertainty analysis, Bipolar-plates, Electrical contacts, Keys parameters, Measurement methods, PEM fuel cell, Power terminals, Resistance measurement, Screw connections, Contact resistance
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-61352 (URN)10.1016/j.jpowsour.2022.232341 (DOI)2-s2.0-85142179649 (Scopus ID)
Note

Funding details: Horizon 2020 Framework Programme, H2020; Funding details: H2020 Marie Skłodowska-Curie Actions, MSCA, 764977; Funding details: Stiftelsen för Strategisk Forskning, SSF, ARC19-0026; Funding details: Stiftelsen för Kunskaps- och Kompetensutveckling, KKS; Funding details: Horizon 2020; Funding text 1: This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 764977, Swedish Foundation for Strategic Research (Project No. ARC19-0026), the ALUSAP project within the strategic innovation programme Metallic materials funded by Vinnova, Formas and Energimyndigheten, the Smart Industry Sweden project funded by the Swedish Knowledge Foundation. The authors would like to thank LPTech AB for performing the coating of the samples and Powercell AB for their input on the project.; Funding text 2: This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 764977 , Swedish Foundation for Strategic Research (Project No. ARC19-0026 ), the ALUSAP project within the strategic innovation programme Metallic materials funded by Vinnova , Formas and Energimyndigheten , the Smart Industry Sweden project funded by the Swedish Knowledge Foundation .

Available from: 2022-12-09 Created: 2022-12-09 Last updated: 2023-05-25Bibliographically approved
Zendejas Medina, L., Mølmen, L., Paschalidou, E.-M., Donzel-Gargand, O., Leisner, P., Jansson, U. & Nyholm, L. (2023). Extending the Passive Region of CrFeNi-Based High Entropy Alloys. Advanced Functional Materials
Open this publication in new window or tab >>Extending the Passive Region of CrFeNi-Based High Entropy Alloys
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2023 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028Article in journal (Refereed) Epub ahead of print
Abstract [en]

This study provides principles for designing new corrosion resistant high entropy alloys. The theoretical framework is a percolation model developed by Newman and Sieradzki that predicts the ability of an alloy to passivate, i.e., to form a protective surface oxide, based on its composition. Here, their model is applied to more complex materials than previously, namely amorphous CrFeNiTa and CrFeNiW alloys. Furthermore, the model describes a more complex passivation process: reforming the oxide layer above the transpassive potential of Cr. The model is used to predict the lowest concentration of Ta or W required to extend the passive region, yielding 11–14 at% Ta and 14–17 at% W. For CrFeNiTa, experiments reveal a threshold value of 13–15 at% Ta, which agrees with the prediction. For CrFeNiW, the experimentally determined threshold value is 37–45 at% W, far above the predicted value. Further investigations explore why the percolation model fails to describe the CrFeNiW system; key factors are the higher nobility and the pH sensitivity of W. These results demonstrate some limitations of the percolation model and offer complementary passivation criteria, while providing a design route for combining the properties of the 3d transition metal and refractory metal groups. © 2023 The Authors.

Place, publisher, year, edition, pages
John Wiley and Sons Inc, 2023
Keywords
Cobalt alloys; Corrosion resistance; Entropy; Functional materials; High-entropy alloys; Iron alloys; Passivation; Refractory metals; Tantalum alloys; Ternary alloys; Complex materials; Corrosion-resistant; High entropy alloys; Materials design; Passivation process; Percolation models; Percolation theory; Surface oxide; Theoretical framework; Threshold-value; Solvents
National Category
Materials Chemistry
Identifiers
urn:nbn:se:ri:diva-67359 (URN)10.1002/adfm.202307897 (DOI)2-s2.0-85170376146 (Scopus ID)
Note

The authors acknowledged Myfab Uppsala for providing facilities and experimental support. Myfab is funded by the Swedish Research Council (2019‐00207) as a national research infrastructure. This study was performed in the framework of the competence center FunMat‐II which is financially supported by Vinnova (Grant No. 2016‐05156). L.M. and P.L. acknowledged the funding from Swedish Foundation for Strategic Research (Project No. ARC19‐0026) and the Smart Industry Sweden project funded by the Swedish Knowledge Foundation.

Available from: 2023-09-22 Created: 2023-09-22 Last updated: 2023-09-22Bibliographically approved
Eiler, K., Mölmen, L., Fast, L., Leisner, P., Sort, J. & Pellicer, E. (2022). Oxygen reduction reaction and proton exchange membrane fuel cell performance of pulse electrodeposited Pt–Ni and Pt–Ni–Mo(O) nanoparticles. Materials Today Energy, 27, Article ID 101023.
Open this publication in new window or tab >>Oxygen reduction reaction and proton exchange membrane fuel cell performance of pulse electrodeposited Pt–Ni and Pt–Ni–Mo(O) nanoparticles
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2022 (English)In: Materials Today Energy, ISSN 2468-6069, Vol. 27, article id 101023Article in journal (Refereed) Published
Abstract [en]

Proton exchange membrane fuel cells (PEMFCs) are an important alternative to fossil fuels and a complement to batteries for the electrification of vehicles. However, their high cost obstructs commercialization, and the catalyst material, including its synthesis, constitutes one of the major cost components. In this work, Pt–Ni and Pt–Ni–Mo(O) nanoparticles (NPs) of varying composition have been synthesized in a single step by pulse electrodeposition onto a PEMFC's gas diffusion layer. The proposed synthesis route combines NP synthesis and their fixation onto the microporous carbon layer in a single step. Both Pt–Ni and Pt–Ni–Mo(O) catalysts exhibit extremely high mass activities at oxygen reduction reaction (ORR) with very low Pt loadings of around 4 μg/cm2 due to the favorable distribution of NPs in contact with the proton exchange membrane. Particle sizes of 40–50 nm and 40–80 nm were obtained for Pt–Ni and Pt–Ni–Mo(O) systems, respectively. The highest ORR mass activities were found for Pt67Ni33 and Pt66Ni32–MoOx NPs. The feasibility of a single-step electrodeposition of Pt–Ni–Mo(O) NPs was successfully demonstrated; however, the ternary NPs are of more amorphous nature in contrast to the crystalline, binary Pt–Ni particles, due to the oxidized state of Mo. Nevertheless, despite their heterogeneous nature, the ternary NPs show homogeneous behavior even on a microscopic scale. © 2022 The Author(s)

Place, publisher, year, edition, pages
Elsevier Ltd, 2022
Keywords
Electrocatalysis, Electrosynthesis, Hydrogen energy, PEM fuel cell, Pulse electrodeposition, Binary alloys, Catalysts, Diffusion in gases, Electrodeposition, Electrodes, Electrolytic reduction, Fossil fuels, Microporosity, Molybdenum oxide, Nanoparticles, Oxygen, Proton exchange membrane fuel cells (PEMFC), Synthesis (chemical), Fuel cell performance, Mass activity, Oxygen reduction reaction, Proton-exchange membranes fuel cells, Single-step, Ternary nanoparticles
National Category
Chemical Sciences
Identifiers
urn:nbn:se:ri:diva-59325 (URN)10.1016/j.mtener.2022.101023 (DOI)2-s2.0-85130796696 (Scopus ID)
Note

 Funding details: H2020 Marie Skłodowska-Curie Actions, MSCA, 764977; Funding details: Generalitat de Catalunya, 2017-SGR-292, PID2020-116844RB-C21; Funding details: Horizon 2020; Funding text 1: This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 764977, the Generalitat de Catalunya under project 2017-SGR-292, and the Spanish government under project PID2020-116844RB-C21. The authors want to express their thanks to Freudenberg, Germany, who gladly supported the GDL material for this study.

Available from: 2022-06-13 Created: 2022-06-13 Last updated: 2023-05-25Bibliographically approved
Mölmen, L., Lundblad, A. O., Fast, L., Zanella, C. & Leisner, P. (2019). Investigation of feed water impurities on life-time of PEMWE. In: : . Paper presented at 2nd International Conference on Electrolysis Loen, Norway - June 9-13, 2019. , Article ID 158.
Open this publication in new window or tab >>Investigation of feed water impurities on life-time of PEMWE
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2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

With the introduction of fuel cell electric vehicles (FCEV), hydrogen gas produced without fossil fuels Is requiredto reduce the CO2 emissions. At the same time, the production of renewable energy is increasing. Waterelectrolysis to produce hydrogen with the use of electricity from renewable sources allows for storage of theenergy in the form of hydrogen. The gas can be utilized either back to the electric net or as fuel for FCEVs.However, the cost of water electrolysis systems needs to be reduced while the lifetime must be increased. Oneof the main limitations of the proton exchange membrane water electrolyser (PEMWE) system is the degradationof the membrane1. This limits the lifetime of the system and is expensive to replace. It has been shown thatimpurities from feed water and the degradation products from other component poison the membrane, loweringthe proton conductivity. Furthermore, metal ion impurities catalyse the formation of hydrogen peroxide at thecathode further contributing to irreversible membrane thinning2. In industrial systems, the water circulated tothe cells is purified to minimize the degradation. However, the purification limits the operating temperature ofthe systems and increases the total system cost2.The water quality used in most electrolysis cells today utilises ASTM type II deionized water. However, littleresearch is done on the limitations, and quantifying the reduction in efficiency dependent on the water quality.Dedigama et al.3 calculated the minimum flow needed, and further state that in industry, 5 times the necessaryflow of water is circulated to ensure proper wetting of the membrane. However, in research, an excess of wateris often used, up to 100 times higher flow than required, to exclude mass transport restrictions on thereactions3,4.Increasing temperature decreases the kinetic overpotential and increases the membrane conductivity4.However, also dissolution of the catalyst and degradation of the cell components increase with temperature.Furthermore, in industrial applications the maximum temperature of the water into the purification system is60°C5. Dependent on the aim of the research, experiments at temperatures as low as 25°C are performed to fitwith the industry, while others run at 80 or 90°C to probe the upper limits of current density and efficiency2.In this project we aim to analyse the effect of varying water purity on the membrane degradation in a single PEMelectrolysis cell test setup. Furthermore, the effect of changing temperature from 60 to 80°C on the impuritytolerance will be studied. The circulating feed water will be analysed with respect to conductivity, metal ion andfluorine concentration. A parallel “blank” system with only tubings, fittings etc will be assembled and comparedto the data measured from the electrolyser. Contaminating species will be added to the feed water to study theirimpact.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-39775 (URN)
Conference
2nd International Conference on Electrolysis Loen, Norway - June 9-13, 2019
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2023-05-25Bibliographically approved
Mölmen, L., Fast, L., Andreatta, F. & Leisner, P. (2019). Pitting corrosion on coated stainless steel PEMFC flow plates. In: : . Paper presented at Electrochem 2019, Glasgow, United Kingdom.
Open this publication in new window or tab >>Pitting corrosion on coated stainless steel PEMFC flow plates
2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

The bipolar plate(BPP) constitutes up to 28% of the PEMFC stack cost[1]. Cheaper and more lightweight materials are needed, while there are strict requirements on both the mechanical and chemical stability within the acidic environment of the fuel cell. The targets set by the US DOE are a corrosion current <1 μA/cm2 and interfacial contact resistance <0.01 ohm cm2[2].

Stainless steel is affordable and has the mechanical stability required for the BPPs. However, SS is subject to corrosion in the PEMFC environment. To be able to reach the DOE goals, either noble metal or conductive ceramic coatings must be utilised[3]. In this work, commercially available coatings on hydroformed SS 316L flow plates are studied. A single cell fuel cell tester is used to age the samples, and the in-situ degradation is measured by impedance measurements and polarisation curves. The electrochemical micro-cell technique is utilised to study the corrosion on both the pristine and aged flow plates by polarisation. SEM is used to analyse the surface. The aim is to better understand the pitting corrosion on PEMFC flow plates.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-42462 (URN)
Conference
Electrochem 2019, Glasgow, United Kingdom
Available from: 2020-01-08 Created: 2020-01-08 Last updated: 2023-05-25Bibliographically approved
Mölmen, L., Braun, M., Baumgärtner, M. & Leisner, P. (2019). Pt-P catalyst for fuel cells. In: : . Paper presented at 4th WORKSHOP e-MINDs, COST Action MP1407, Milano, 13-15/2, 2019.
Open this publication in new window or tab >>Pt-P catalyst for fuel cells
2019 (English)Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Fuel cell technology is becoming increasingly important in a society where the energy system is changing toward a high degree of electrification based on fossil-free primary sources of energy. Among commercial fuel cells, PEM (polymer electrolyte membrane) technology is dominating and the production is doubled each year. The reason for PEM technology being so prosperous is the ability of the industry to manufacture thin film materials (electrodes, membranes and protective films on bipolar plates), while also reaching high current densities. In order to improve the efficiency, catalysts are applied in the electrodes. These improvements have been achieved during the last decades thanks to significant materials development of membranes and electrodes, including micro- and nano-structuring and catalyst development by materials-doping. Thus, PEM technology has a strong potential to offer sustainable, cost effective and flexible solutions.

However, PEM technology is sensitive to contamination of catalysts and membrane. Additionally, the demanding internal environment (chemistry, temperature, pressure, and dynamic operation make the conditions very harsh) poses complex challenges in terms of durability. Therefore, there are still challenges to overcome to make PEM technology more efficient and robust and thereby beneficial. The most important areas of materials development to reduce the cost of PEM fuel cells are

  • High-performance electrode catalysts enabling ultra-low precious metal loading,
  • Lower cost, lighter, corrosion-resistant bipolar plates,
  • Low cost, high-performance membranes.

The purpose of the present work is synthesis of catalytic Pt and PtP nanoparticles onto the gas diffusion layer (GDL) of PEM fuel cells by electrodeposition, and in a next step to study aging during fuel cell testing.

Pt particles with varying P concentration are electrodeposited onto the carbon paper GDL. The concentrations used were 0 at% P, 1 at% P and 10 at% P. The GDL is activated by plasma etching prior to electroplating. The electrolyte used, contained 8 gL-1 Pt as Pt(NO2)2(NH3)2, 70 gL-1  NaCH3COOH and 100 gL-1  Na2CO3. Phosphorous was added in the form of H3PO3. Pulsed electrodeposition was performed at a temperature of 30 °C with an on-time of 0.005 seconds and off-time of 0.195 s. The peak current was 5 A.

National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:ri:diva-39313 (URN)
Conference
4th WORKSHOP e-MINDs, COST Action MP1407, Milano, 13-15/2, 2019
Available from: 2019-07-02 Created: 2019-07-02 Last updated: 2023-05-25Bibliographically approved
Mölmen, L., Alexandersson, A. & Leisner, P. (2019). Surface technology should improve PEM fuel cell performance. Transactions of the Institute of Metal Finishing, 97(3), 112-114
Open this publication in new window or tab >>Surface technology should improve PEM fuel cell performance
2019 (English)In: Transactions of the Institute of Metal Finishing, ISSN 0020-2967, E-ISSN 1745-9192, Vol. 97, no 3, p. 112-114Article in journal (Refereed) Published
Abstract [en]

Leading industrial nations are investing in hydrogen technology as energy storage solution with fuel cells as the main converter to electric energy. Improvements in the performance of the key components: electrode catalyst, bipolar plates and polymer electrolyte membrane are needed to reduce costs for mass-market introduction. Consequently, surface technology has an essential role in meeting the goals. 

Place, publisher, year, edition, pages
Taylor and Francis Ltd., 2019
Keywords
bipolar plate, catalyst, corrosion, hydrogen, Catalysts, Fuel cells, Hydrogen storage, Polyelectrolytes, Bipolar plates, Electrode catalysts, Hydrogen technologies, Industrial nations, Market introduction, Polymer electrolyte membranes, Storage solutions, Surface technology, Proton exchange membrane fuel cells (PEMFC)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38893 (URN)10.1080/00202967.2019.1596573 (DOI)2-s2.0-85065790068 (Scopus ID)
Note

Funding details: Horizon 2020; Funding details: Horizon 2020 Framework Programme, H2020; Funding text 1: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 764977.

Available from: 2019-06-03 Created: 2019-06-03 Last updated: 2023-05-25Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2788-960x

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