Energibolagen gör stora investeringar för att tillhandahålla infrastruktur för produktion, distribution och tankning av vätgas. Det är därför viktigt att hitta de mest effektiva och genomförbara scenarierna för väte i samhället. Detta innebär att välja mellan värdekedjor för flytande väte (LH2) eller komprimerad vätgas (CGH2) i stegen från produktion till lagring ombord på fordon inom transportsegment, till exempel tunga lastbilar. Under projektet övervägdes också det ännu oetablerade konceptet med kryo-komprimerad vätgas (CcH2). Projektet syftade till att identifiera de kritiska utmaningarna och nuvarande begränsningar som påverkar den utbredda användningen av väte som bränsle för transporttillämpningar. Det har fokuserat på att öka kunskapen om teknologier som kan göra LH2- eller CGH2-infrastruktur och fordonsanvändning effektivare och säkrare, genom att bedöma den aktuella teknikens nivå såväl som mognad samt potential för ny teknik. I detta ingick också ett segment fokuserat på säkerhetsrisker kring alternativen längs de senare delarna av värdekedjan. Projektet som helhet genomfördes som en litteraturstudie. För teknologimognaden i olika delar av värdekedjan har projektet sammanfattat resultaten i ett kategoriseringssystem på mycket hög nivå, se tabell nedan. Definitionerna är huvudsakligen kvalitativa i följande kategorier: • Etablerad (används i större skala, ~TRL 9-10) • Beprövat koncept (demonstranter eller snart det här stadiet, ~TRL 7-8) • Initial design (inga offentliga demonstratorer tillgängliga, ~TRL 3-6) • Osäker tillämplighet (tillämpligheten fastställdes inte i detta arbete) • Ej tillämpbart (Kan inte användas för detta tillstånd av väte) Tabellen ovan ger också en översikt över de segment som ingår i rapporten. I kombination med den tekniska utvärderingen gjordes också en kvalitativ kostnadsanalys av de olika fastillstånden för väte. Här indikeras att även om LH2 har en högre kostnad i den inledande delen av värdekedjan, har den lägre kostnader i slutsegmenten. Därför är det möjligt att slutpriset för användaren blir liknande för både LH2 och CGH2. Hela kostnaden kan jämföras först när LH2 tankstationer och fordon byggs offentligt och kostnadsinformation är tillgänglig. Detsamma gäller för CcH2. Under förstudien för säkerhet, föreskrifter och standarder kom följande slutsats: Ur ett säkerhetsperspektiv finns det inga oöverstigliga barriärer med avseende på användningen av LH2 ombord på tunga vägfordon på medellång sikt, men det finns flera utmaningar att övervinna, inte minst på kort sikt. Inom EU finns regler som tillåter typgodkännande av tunga vägfordon med LH2 lagringssystem. Dessa är dock baserade på arbete som utfördes för 15 - 20 år sedan och är allmänt erkända som i behov av att uppdateras och valideras på samma sätt som CGH2 vägfordonsreglerna har varit. Det finns även en brist på uppdaterade industristandarder för LH2-lagringssystem för vägfordon. En särskild lucka är avsaknaden av en uppdaterad standard som kan refereras till i föreskrifter för munstycket i tanköppningens geometri. För LH2-påfyllningsstationer som helhet finns det dessutom inga lämpliga, uppdaterade internationella standarder, så det finns en risk att enskilda länder ställer sina egna krav. Sammantaget drog projektet slutsatsen att det inte finns några oöverkomliga hinder för implementeringen av LH2. Det är en genomförbar värdekedja ur både teknologiska-, kostnads- och säkerhetsperspektiv. Den kan också i framtiden bli jämförbar med den mer beprövade värdekedjan CGH2, men vissa initiala hinder och investeringar måste övervinnas.

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)

Study concerning electrical connections during long periods of operation at Swedish nuclear power plants

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.

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)

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.

Research on fuel cell technology is constantly gaining importance, while global emission requirements are becoming more and more restrictive. For environmentally neutral proton exchange membrane fuel cells (PEMFCs) to become a competitive technology, sustainable infrastructures need to be established. One of the main showstoppers is the utilization of the rare and therefore costly precious metal Pt as the key element in the electrocatalysis of hydrogen and oxygen. A huge amount of research is done on immensely reducing or even replacing Pt for future PEMFC technology. In this research update, the progress on oxygen reduction reaction catalysts in acidic media over the past two years is reviewed, with special attention to their durability. © 2021 Author(s).

Purpose: This article presents a proposal for an operating cycle format for describing transport missions of road vehicles, for example a logging truck fetching its cargo. The primary application is in dynamic simulation models for evaluation of energy consumption and other costs of transportation. When applied to product development, the objective is an ensemble of components and functions optimised for specific tasks and environments. When applied to selection of vehicle configuration, the objective is a vehicle specification tailored for its task. Method: The proposal is presented and its four main parts: road, weather, traffic and mission, are thoroughly explained. Furthermore, we implement the proposal in an example of a dynamic forward simulation model. Results: The example model is used for two case studies: a synthetic example of a complex transport mission (a logging truck fetching its cargo) that shows some advanced format features, and an example from a real vehicle log file (cargo transport) that seeks to compare the resulting simulated speed profile to the measured one. Conclusion: The results show that the proposed format works in practice. It can represent complex transport missions and it can be used to reproduce the main features of a logged speed profile even when combined with simple driver and vehicle models.

We propose a novel statistical description of the physical properties of road transport operations by using stochastic models arranged in a hierarchical structure. The description includes speed signs, stops, speed bumps, curvature, topography, road roughness and ground type, with a road type introduced at the top of the hierarchy to group characteristics that are often connected. Methods are described how to generate data on a form (the operating cycle format) that can be used in dynamic simulations to estimate energy usage and CO2 emissions. To showcase the behaviour of the description, two examples are presented using a modular vehicle model for a heavy-duty truck: a sensitivity study on impacts from changes in the environment, and a comparison study on a real goods transport operation with respect to energy usage. It is found that the stop intensity and topography amplitude have the greatest impact in the sensitivity study (8.3% and 9.5% respectively), and the comparison study implies that the statistical description is capable of capturing properties of the road that are significant for vehicular energy usage. Moreover, it is discussed how the statistical description can be used in a vehicle design process, and how the mean CO2 emissions and its variation can be estimated for a vehicle specification.

Nb-Ge-C nanocomposite thin films were deposited by dc magnetron sputtering using three elemental targets. The films consist of substoichiometric NbC x in a nanometer-thick matrix of amorphous C and Ge. Films with no Ge contain grains that are elongated in the growth direction with a (111) preferred crystallographic orientation. With the addition of ∼12 at. % Ge, the grains are more equiaxed and exhibit a more random orientation. At even higher Ge contents, the structure also becomes denser. The porous structure of the low Ge content films result in O uptake from the ambient. With higher C content in the films both the amount of amorphous C and C/Nb-ratio increases. The contact resistance was measured by four-point technique as a function of contact force between 0 and 10 N. The lowest contact resistance (1.7 mΩ) is obtained at 10 N. The resistivity varies between 470 and 1700 μΩ·cm depending on porosity and O content.