Publications

Interest in hydrogen fuel is growing for automotive applications; however safe dense solid-state hydrogen storage remains a formidable scientific challenge. Metal hydrides offer ample storage capacity and do not require cryogens or exceedingly high pressures for operation. However hydrides have largely been abandoned because of oxidative instability and sluggish kinetics. We report a new environmentally stable hydrogen storage material constructed of Mg nanocrystals encapsulated by atomically thin and gas-selective reduced graphene oxide (rGO) sheets. This material protected from oxygen and moisture by the rGO layers exhibits exceptionally dense hydrogen storage (6.5 wt% and 0.105 kg H₂ per litre in the total composite). As rGO is atomically thin this approach minimizes inactive mass in the composite while also providing a kinetic enhancement to hydrogen sorption performance. These multilaminates of rGO-Mg are able to deliver exceptionally dense hydrogen storage and provide a material platform for harnessing the attributes of sensitive nanomaterials in demanding environments.

In this paper we propose and verify a novel method to simulate crack propagation without propagating a crack by finite element method. We propose this method for elastoplastic analysis coupled with convection-diffusion. In the previous study we succeeded in performing elastoplastic analysis coupled with convection-diffusion of hydrogen for a material with a crack under tensile loading. This research extends the successful method to fatigue crack propagation. In convection-diffusion analysis in order to simulate the invasion and release of elements through the free surface the crack tip is expressed by using a notch with a sufficiently small radius. Therefore the node release method conventionally used to simulate crack propagation cannot be applied. Hence instead of crack propagation based on an analytical model we propose a novel method that can reproduce the influence of the vicinity of the crack tip on a crack. We moved the stress field near the crack tip in the direction opposite to that of crack propagation by an amount corresponding to the crack propagation length. When we extend the previous method to fatigue crack propagation simulation we must consider the difference in strain due to loading and unloading. This problem was solved by considering the strain due to loading as a displacement. Instead of moving the strain due to loading we moved the displacement. First we performed a simple tensile load analysis on the model and output the displacement of all the nodes of the model at maximum load. Then the displacement was moved in the direction opposite to that of crack propagation. Finally the stress field was reproduced by forcibly moving all the nodes by the displacement amount. The strain due to unloading was reproduced by removing the displacement. Furthermore we verified the equivalence of the crack propagation simulation and the proposed method.

E4tech’s 6th annual review of the global fuel cell industry is now available here. Using primary data straight from the main players and free to download it quantifies shipments by fuel cell type by application and by region of deployment and summarises industry developments over the year.



2019 saw shipments globally grow significantly to 1.1 GW. Numbers grew slightly to around 70000 units. The growth in capacity came mainly from cars Hyundai with its NEXO and Toyota with its Mirai together accounting for around two-thirds of shipments by capacity. Unit numbers are still dominated by Japan’s ene-Farm cogeneration appliances at around 45000 shipments. Large numbers of trucks and buses are now manufactured and shipped in China though numbers deployed are limited by the availability of refuelling infrastructure. But growth in China is uncertain as policy changes are under discussion.



2020 looks like it will be an even bigger year again dominated by Hyundai and Toyota. The Japanese fuel cell market is expected also to grow partly on the back of the Tokyo ‘Hydrogen Olympics’. Korea is another growth story buoyed by its latest roadmap which aims to shift large swathes of its economy to hydrogen energy by 2040. Elsewhere much of the supply chain development is in heavy duty vehicles and big supply chain players like Cummins Weichai and Michelin are making significant investments.

Maritime transport faces increasing pressure to reduce its greenhouse gas emissions to be in accordance with the Paris Agreement. For this to happen low- and zero-carbon energy solutions need to be developed. In this paper we draw on sustainability transition literature and introduce the technological innovation system (TIS) framework to the field of maritime transportation research. The TIS approach analytically distinguishes between different innovation system functions that are important for new technologies to develop and diffuse beyond an early phase of experimentation. This provides a basis for technology-specific policy recommendations. We apply the TIS framework to the case of battery-electric and hydrogen energy solutions for coastal maritime transport in Norway. Whereas both battery-electric and hydrogen solutions have developed rapidly the former is more mature and has a strong momentum. Public procurement and other policy instruments have been crucial for developments to date and will be important for these technologies to become viable options for shipping more generally.

Electrifying energy-intensive processes is currently intensively explored to cut greenhouse gas (GHG) emissions through renewable electricity. Electrification is particularly challenging if fossil resources are not only used for energy supply but also as feedstock. Copper production is such an energy-intensive process consuming large quantities of fossil fuels both as reducing agent and as energy supply.

Here we explore the techno-economic potential of Power-to-Hydrogen to decarbonize copper production. To determine the minimal cost of an on-site retrofit with Power-to-Hydrogen technology we formulate and solve a mixed-integer linear program for the integrated system. Under current techno-economic parameters for Germany the resulting direct CO₂ abatement cost is 201 EUR/t CO₂-eq for Power-to-Hydrogen in copper production. On-site utilization of the electrolysis by-product oxygen has a substantial economic benefit. While the abatement cost vastly exceeds current European emission certificate prices a sensitivity analysis shows that projected future developments in Power-to-Hydrogen technologies can greatly reduce the direct CO₂ abatement cost to 54 EUR/t CO₂-eq. An analysis of the total GHG emissions shows that decarbonization through Power-to-Hydrogen reduces the global GHG emissions only if the emission factor of the electricity supply lies below 160 g CO2-eq/kWhel.

The results suggest that decarbonization of copper production by Power-to-Hydrogen could become economically and environmentally beneficial over the next decades due to cheaper and more efficient Power-to-Hydrogen technology rising GHG emission certificate prices and further decarbonization of the electricity supply.

A solid-state storage system is the most practical option for hydrogen because it is more convenient and safer. Metal hydrides especially MgH₂ are the most promising materials that offer high gravimetric capacity and good reversibility. However the practical application of MgH₂ is restricted by slow sorption kinetics and high stability of thermodynamic properties. Hydrogen storage performance of MgH₂ was enhanced by introducing the Mg–Na–Al system that destabilises MgH₂ with NaAlH₄. The Mg–Na–Al system has superior performance compared to that of unary MgH₂ and NaAlH₄. To boost the performance of the Mg–Na–Al system the ball milling method and the addition of a catalyst were introduced. The Mg–Na–Al system resulted in a low onset decomposition temperature superior cyclability and enhanced kinetics performances. The Al12Mg17 and NaMgH₃ that formed in situ during the dehydrogenation process modify the reaction pathway of the Mg–Na–Al system and alter the thermodynamic properties. In this paper the overview of the recent progress in hydrogen storage of the Mg–Na–Al system is detailed. The remaining challenges and future development of Mg–Na–Al system are also discussed. This paper is the first review report on hydrogen storage properties of the Mg–Na–Al system.

Hydrogen characterization techniques like melt extraction and thermal desorption spectroscopy (TDS) are useful tools in order to evaluate and understand the interaction between hydrogen and metals. These two techniques are used here on cold deformed ultra-low carbon (ULC) steel with and without hydrogen induced damage. The material is charged electrochemically in order to induce varying amounts of hydrogen and variable degrees of hydrogen induced damage. The aim of this work is to evaluate to which extent the hydrogen induced damage would manifest itself in melt extraction and TDS measurements.

Experimental evidence exists for the enhancement of the hydrogen storage capacity of porous carbons when these materials are doped with metal nanoparticles. One of the most studied dopants is palladium. Dissociation of the hydrogen molecules and spillover of the H atoms towards the carbon substrate has been advocated as the reason for the enhancement of the storage capacity. We have investigated this mechanism by performing ab initio density functional molecular dynamics (AIMD) simulations of the deposition of molecular hydrogen on Pd6 clusters anchored on graphene vacancies. The clusters are initially near-saturated with atomic and molecular hydrogen. This condition would facilitate the occurrence of spillover since our energy calculations based on density functional theory indicate that migration of preadsorbed H atoms towards the graphene substrate becomes exothermic on Pd clusters with high hydrogen coverages. However AIMD simulations show that the H atoms prefer to intercalate and absorb within the Pd cluster rather than migrate to the carbon substrate. These results reveal that high activation barriers exist preventing the spillover of hydrogen from the anchored Pd clusters to the carbon substrate.

The glass industry is part of the energy-intensive industry posing a major challenge to fulfill the CO₂ reduction targets of the Paris Climate Agreement. The segments of the glass industry e.g. container or flat glass are quite diverse and attribute to different glass products with different requirements to product quality and various process options. To address the challenge of decarbonizing the glass industry firstly an inventory of current glass products processes and applied technologies in terms of energy efficiency and CO₂ emissions is conducted. Secondly decarbonization options are identified and structured according to fuel substitution waste heat recovery and process intensification. Due to the high share of energy-related CO₂ emissions electrical melting and hydrogen combustion or a combination of both are the most promising options to decarbonize the glass industry but further research design adjustments and process improvements are necessary. Furthermore electricity and hydrogen prices have to decrease or fossil fuels must become more expensive to be cost-competitive relative to fossil fuels and respective infrastructures have to be constructed or adjusted. Various heat recovery options have great potential for CO₂ savings but can be technically challenging or have not yet been considered for techno-economic reasons.

Hydrogen technologies have received increased attention in research and development to foster the shift towards carbon-neutral energy systems. Depending on the specific production techniques transportation concepts and application areas hydrogen supply chains (HSCs) can be anything from part of the energy transition problem to part of the solution: Even more than battery-driven electric mobility hydrogen is a polyvalent technology and can be used in very different contexts with specific positive or negative sustainability impacts. Thus a detailed sustainability evaluation is crucial for decision making in the context of hydrogen technology and its diverse application fields. This article provides a comprehensive structured literature review in the context of HSCs along the triple bottom line dimensions of environmental economic and social sustainability analyzing a total of 288 research papers. As a result we identify research gaps mostly regarding social sustainability and the supply chain stages of hydrogen distribution and usage. We suggest further research to concentrate on these gaps thus strengthening our understanding of comprehensive sustainability evaluations for HSCs especially in social sustainability evaluation. In addition we provide an additional approach for discussion by adding literature review results from neighboring fields highlighting the joint challenges and insights regarding sustainability evaluation.