Large investments are being made by energy companies to provide hydrogen production, distribution, and refuelling infrastructure. It is hence critical to find hydrogen pathways that are efficient and feasible. This means deciding between the usage of liquid hydrogen (LH2) or compressed hydrogen (CGH2) value-chains from production to storage onboard vehicles in some transport segments such as heavy-duty trucks. During the project the as yet unestablished concept of cryo-compressed hydrogen (CcH2) was also considered. The project aimed at identifying the critical challenges and current limitations that impact the widespread use of hydrogen as a fuel for transport applications. It has focused on increasing the knowledge about technologies that can make LH2 or CGH2 infrastructure and vehicle usage more efficient and safer, by assessing the current state of technology as well as maturity and potential of new technologies. Included in this was also a segment focused on the safety of the different alternatives along the later parts of the value-chain. The project as a whole was conducted as a literature study. For the technology maturity in different parts of the value-chain the project has summarized the results in a very high-level categorisation system, see table below The definitions are mainly qualitatively and show where the technologies are in these categories: • Established (Used on a larger scale, ~TRL 9-10) • Proven concept (Demonstrators or soon reaching this stage, ~TRL 7-8) • Initial design (No public demonstrators available, ~TRL 3-6) • Uncertain applicability (Applicability was not established in this work) • Not applicable (Cannot be used for this state of hydrogen) Technological maturity in the hydrogen value-chain The table above also gives an overview of the segments included in the report. In combination with the technological evaluation a qualitative cost analysis of the different hydrogen storage states was also done. Here it is indicated that though LH2 has a higher cost in the initial part of the value-chain, it has lower costs in the end segments. Therefore, it is possible that the end-price for the user will be similar for both LH2 and CGH2. The full cost can be compared first when LH2 refuelling stations and vehicles are publicly built, and cost information is available. The same is true for CcH2. During the safety, regulations and standards pre-study the following was concluded. From a safety perspective, there are no insurmountable barriers with respect to the use of LH2 on-board heavy-duty road vehicles in the medium term, however, there are several challenges to overcome, not least in the short term. Within the EU there are regulations which allow the type-approval of heavy-duty road vehicles with LH2 storage systems. However, these are based on work undertaken 15 - 20 years ago and are widely acknowledged as in need of being updated and validated in the same way that CGH2 road vehicle regulations have been. Similarly, there is a lack of up-to-date industry standards for road vehicle LH2 storage systems. A particular gap is the absence of an up-to-date standard that can be referenced in regulations for the refuelling receptacle geometry. Additionally, for LH2 refilling stations as a whole there are no suitable, up to date international standards, so there is a risk that individual countries set their own requirements. Overall, the project concluded that there are no show-stoppers for the implementation of LH2. It is a feasible value-chain from both the technology, cost and safety perspective. It could also in the future become comparable with the more proven CGH2 value-chain, but some initial hurdles and investments need to be overcome.

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. 

Supercapacitors (SCs) represent an environmentally friendly technology, that can replace batteries or work with them in high power density applications. To support the increasing use of SCs, accurate characterization is required under operating conditions. In addition, validated circuital and software models are needed to identify the SCs behavior in dynamic applications. Along with slower but highly accurate methods, novel quick, traceable, and effective measurement techniques are required to evaluate SCs State of Charge (SoC) and State of Health (SoH) and to promote the uptake of SCs in consumer electronics, energy, transport, aerospace and in many other applications. The MetSuperCap project aims to improve the characterization of SCs by providing an accurate identification of their parameters in the laboratory and under operational conditions.