%0 journal article %@ 1385-8947 %A Neves, A.M., Puszkiel, J., Capurso, G., Bellosta von Colbe, J.M., Klassen, T., Jepsen, J. %D 2023 %J Chemical Engineering Journal %P 142274 %R doi:10.1016/j.cej.2023.142274 %T Development of a new approach for the kinetic modeling of the lithium reactive hydride composite (Li-RHC) for hydrogen storage under desorption conditions %U https://doi.org/10.1016/j.cej.2023.142274 %X Among some promising candidates for high-capacity energy and hydrogen storage is the Lithium-Boron Reactive Hydride Composite System (Li-RHC: 2 LiH + MgB2/2 LiBH4 + MgH2). This system desorbs hydrogen only at relatively high temperatures and presents a two-step series of reactions occurring in different time scales: first, MgH2 desorbs, followed by LiBH4. Hitherto, the dehydrogenation kinetic behavior of such a system has been described for different temperatures at specific values of operative pressure. However, a comprehensive model representing its dehydrogenation kinetic behavior under different operative conditions has not yet been developed. Herein, the separable variable method is applied to develop a comprehensive kinetic model, including the two-step dehydrogenation series reaction. The MgH2 decomposition is described with the one-dimensional interface-controlled reaction rate Johnson-Mehl-Avrami-Erofeyev-Kholmogorov (JMAEK) with a (Pequilibrium/Poperative) pressure functionality and an Arrhenius temperature dependence activation energy of 63 ± 3 kJ/mol H2. The LiBH4 decomposition is modeled applying the autocatalytic Prout-Tompkins model. A novel approach to describe the Prout-Tompkins t0 parameter as a function of the operative temperature and pressure model is proposed. This second reaction step presented a (Pequilibrium – Poperative/Pequilibrium)2 pressure dependence and an Arrhenius temperature dependence with activation energy 94 ± 13 kJ/mol H2. The proposed approach is experimentally and computationally validated, successfully describing the decomposition kinetic behavior of MgH2 and LiBH4 under three-phase gas, liquid and solid environment and shows good agreement between experimental and modeled curves. %0 journal article %@ 2516-1083 %A Dornheim, M., Baetcke, L., Akiba, E., Ares, J., Autrey, T., Barale, J., Baricco, M., Brooks, K., Chalkiadakis, N., Charbonnier, V., Christensen, S., Bellosta von Colbe, J., Costamagna, M., Dematteis, E., Fernández, J., Gennett, T., Grant, D., Heo, T., Hirscher, M., Hurst, K., Lototskyy, M., Metz, O., Rizzi, P., Sakaki, K., Sartori, S., Stamatakis, E., Stuart, A., Stubos, A., Walker, G., Webb, C., Wood, B., Yartys, V., Zoulias, E. %D 2022 %J Progress in Energy %N 4 %P 042005 %R doi:10.1088/2516-1083/ac7cb7 %T Research and development of hydrogen carrier based solutions for hydrogen compression and storage %U https://doi.org/10.1088/2516-1083/ac7cb7 4 %X Recently, the industrial and public interest in hydrogen technologies has strongly risen, since hydrogen is the ideal means for medium to long term energy storage, transport and usage in combination with renewable and green energy supply. Therefore, in a future energy system the production, storage and usage of green hydrogen is a key technology. Hydrogen is and will in future be even more used for industrial production processes as reduction agent or for the production of synthetic hydrocarbons, especially in the chemical industry and refineries. Under certain conditions material based systems for hydrogen storage and compression offer advantages over the classical systems based on gaseous or liquid hydrogen. This includes in particular lower maintenance costs, higher reliability and safety. Hydrogen storage is possible at pressures and temperatures much closer to ambient conditions. Hydrogen compression is possible without any moving parts and only by using waste heat. In this paper, the newest developments of hydrogen carriers for storage and compression are summarized. In addition, an overview of the different research activities in this field are given. %0 journal article %@ 0925-8388 %A Dreistadt, D., Le, T., Capurso, G., Bellosta von Colbe, J., Santhosh, A., Pistidda, C., Scharnagl, N., Ovri, H., Milanese, C., Jerabek, P., Klassen, T., Jepsen, J. %D 2022 %J Journal of Alloys and Compounds %P 165847 %R doi:10.1016/j.jallcom.2022.165847 %T An effective activation method for industrially produced TiFeMn powder for hydrogen storage %U https://doi.org/10.1016/j.jallcom.2022.165847 %X This work proposes an effective thermal activation method with low technical effort for industrially produced titanium-iron-manganese powders (TiFeMn) for hydrogen storage. In this context, the influence of temperature and particle size of TiFeMn on the activation process is systematically studied. The results obtained from this investigation suggest that the activation of the TiFeMn material at temperatures as low as 50 °C is already possible, with a combination of “Dynamic” and “Static” routines, and that an increase to 90 °C strongly reduces the incubation time for activation, i.e. the incubation time of the sample with the two routines at 90 °C is about 0.84 h, while ∼ 277 h is required for the sample treated at 50 °C in both “Dynamic” and “Static” sequences. Selecting TiFeMn particles of larger size also leads to significant improvements in the activation performance of the investigated material. The proposed activation routine makes it possible to overcome the oxide layer existing on the compound surface, which acts as a diffusion barrier for the hydrogen atoms. This activation method induces further cracks and defects in the powder granules, generating new surfaces for hydrogen absorption with greater frequency, and thus leading to faster sorption kinetics in the subsequent absorption-desorption cycles. %0 journal article %@ 0925-8388 %A Hariyadi, A., Suwarno, S., Denys, R., Bellosta von Colbe, J., Saetre, T., Yartys, V. %D 2022 %J Journal of Alloys and Compounds %P 162135 %R doi:10.1016/j.jallcom.2021.162135 %T Modeling of the hydrogen sorption kinetics in an AB2 laves type metal hydride alloy %U https://doi.org/10.1016/j.jallcom.2021.162135 %X Hydrides of the AB2 Laves type alloys (A=Zr, Ti; B = transition metal – Fe, Co, Ni, Mn, Cr, V) have been extensively studied as materials for the storage of gaseous hydrogen. They contain up to 4 H atoms/formula unit AB2, thus achieving reversible H storage capacities in the range between 1.5 and 2.0 wt% H and offering high rates of hydrogen charge and discharge, thus making them suitable for designing efficient hydrogen stores operating at ambient conditions. In the present study, we performed an experimental study and modeling of the thermodynamics and the kinetics of interaction in the AB2-hydrogen system. The experimental data was collected by studying a model alloy with a composition Ti0.15Zr0.85La0.03Ni1.126Mn0.657V0.113Fe0.113. Hydrogen absorption and desorption were studied in a volumetric Sieverts type apparatus at isothermal conditions using a single-step change/discharge and stepwise methods. The results obtained from the model simulation show that the reaction follows the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, with the value of exponent n = 1–1.25 for absorption and 1 for desorption. This indicates that the rate-limiting hydrogen absorption and desorption steps are jointly governed by hydrogen diffusion and grain boundary nucleation of alpha-solid solution and beta-hydride. The activation energies for both hydrogen absorption and desorption decrease along with increasing hydrogen content in the hydride. %0 journal article %@ 2516-1083 %A Pasquini, L., Sakaki, K., Akiba, E., Allendorf, M.D., Alvares, E., Ares, J.R., Babai, D., Baricco, M., Bellosta Von Colbe, J., Bereznitsky, M., Buckley, C.E., Cho, Y.W., Cuevas, F., De Rango, P., Dematteis, E.M., Denys, R.V., Dornheim, M., Fernández, J.F., Hariyadi, A., Hauback, B.C., Heo, T.W., Hirscher, M., Humphries, T.D., Huot, J., Jacob, I., Jensen, T.R., Jerabek, P., Kang, S.Y., Keilbart, N., Kim, H., Latroche, M., Leardini, F., Li, H., Ling, S., Lototskyy, M.V., Mullen, R., Orimo, S.-I., Paskevicius, M., Pistidda, C., Polanski, M., Puszkiel, J., Rabkin, E., Sahlberg, M., Sartori, S., Santhosh, A., Sato, T., Shneck, R.Z., Sørby, M.H., Shang, Y., Stavila, V., Suh, J.-Y., Suwarno, S., Thi Thu, L., Wan, L.F., Webb, C.J., Witman, M., Wan, C., Wood, B.C., Yartys, V.A. %D 2022 %J Progress in Energy %N 3 %P 032007 %R doi:10.1088/2516-1083/ac7190 %T Magnesium- and intermetallic alloys-based hydrides for energy storage: modelling, synthesis and properties %U https://doi.org/10.1088/2516-1083/ac7190 3 %X Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy transition and in the deployment of hydrogen as an efficient energy vector. This review, by experts of Task 40 'Energy Storage and Conversion based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency, reports on the latest activities of the working group 'Magnesium- and Intermetallic alloys-based Hydrides for Energy Storage'. The following topics are covered by the review: multiscale modelling of hydrides and hydrogen sorption mechanisms; synthesis and processing techniques; catalysts for hydrogen sorption in Mg; Mg-based nanostructures and new compounds; hydrides based on intermetallic TiFe alloys, high entropy alloys, Laves phases, and Pd-containing alloys. Finally, an outlook is presented on current worldwide investments and future research directions for hydrogen-based energy storage. %0 journal article %@ 0360-3199 %A Neves, A.M., Puszkiel, J., Capurso, G., Bellosta von Colbe, J.M., Milanese, C., Dornheim, M., Klassen, T., Jepsen, J. %D 2021 %J International Journal of Hydrogen Energy %N 63 %P 32110-32125 %R doi:10.1016/j.ijhydene.2021.06.227 %T Modeling the kinetic behavior of the Li-RHC system for energy-hydrogen storage: (I) absorption %U https://doi.org/10.1016/j.ijhydene.2021.06.227 63 %X The Lithium–Boron Reactive Hydride Composite System (Li-RHC) (2 LiH + MgB2/2 LiBH4 + MgH2) is a high-temperature hydrogen storage material suitable for energy storage applications. Herein, a comprehensive gas-solid kinetic model for hydrogenation is developed. Based on thermodynamic measurements under absorption conditions, the system's enthalpy ΔH and entropy ΔS are determined to amount to −34 ± 2 kJ∙mol H2−1 and −70 ± 3 J∙K−1∙mol H2−1, respectively. Based on the thermodynamic behavior assessment, the kinetic measurements' conditions are set in the range between 325 °C and 412 °C, as well as between 15 bar and 50 bar. The kinetic analysis shows that the hydrogenation rate-limiting-step is related to a one-dimensional interface-controlled reaction with a driving-force-corrected apparent activation energy of 146 ± 3 kJ∙mol H2−1. Applying the kinetic model, the dependence of the reaction rate constant as a function of pressure and temperature is calculated, allowing the design of optimized hydrogen/energy storage vessels via finite element method (FEM) simulations. %0 journal article %@ 0360-3199 %A Yartys, V.A., Lototskyy, M.V., Linkov, V., Pasupathi, S., Davids, M.W., Tolj, I., Radica, G., Denys, R.V., Eriksen, J., Taube, K., Bellosta von Colbe, J., Capurso, G., Dornheim, M., Smith, F., Mathebula, D., Swanepoel, D., Suwarno, S. %D 2021 %J International Journal of Hydrogen Energy %N 72 %P 35896-35909 %R doi:10.1016/j.ijhydene.2021.01.190 %T HYDRIDE4MOBILITY: An EU HORIZON 2020 project on hydrogen powered fuel cell utility vehicles using metal hydrides in hydrogen storage and refuelling systems %U https://doi.org/10.1016/j.ijhydene.2021.01.190 72 %X This article gives an overview of HYDRIDE4MOBILITY project focused on the results generated during its first phase (2017–2019). %0 journal article %@ 1996-1073 %A Puszkiel, J., Bellosta von Colbe, J.M., Jepsen, J., Mitrokhin, S.V., Movlaev, E., Verbetsky, V., Klassen, T. %D 2020 %J Energies %N 11 %P 2751 %R doi:10.3390/en13112751 %T Designing an AB2-Type Alloy (TiZr-CrMnMo) for the Hybrid Hydrogen Storage Concept %U https://doi.org/10.3390/en13112751 11 %X The hybrid hydrogen storage method consists of the combination of both solid-state metal hydrides and gas hydrogen storage. This method is regarded as a promising trade-off solution between the already developed high-pressure storage reservoir, utilized in the automobile industry, and solid-state storage through the formation of metal hydrides. Therefore, it is possible to lower the hydrogen pressure and to increase the hydrogen volumetric density. In this work, we design a non-stoichiometric AB2 C14-Laves alloy composed of (Ti0.9Zr0.1)1.25Cr0.85Mn1.1Mo0.05. This alloy is synthesized by arc-melting, and the thermodynamic and kinetic behaviors are evaluated in a high-pressure Sieverts apparatus. Proper thermodynamic parameters are obtained in the range of temperature and pressure from 3 to 85 °C and from 15 to 500 bar: ΔHabs. = 22 ± 1 kJ/mol H2, ΔSabs. = 107 ± 2 J/K mol H2, and ΔHdes. = 24 ± 1 kJ/mol H2, ΔSdes. = 110 ± 3 J/K mol H2. The addition of 10 wt.% of expanded natural graphite (ENG) allows the improvement of the heat transfer properties, showing a reversible capacity of about 1.5 wt.%, cycling stability and hydrogenation/dehydrogenation times between 25 to 70 s. The feasibility for the utilization of the designed material in a high-pressure tank is also evaluated, considering practical design parameters. %0 journal article %@ 0925-8388 %A Hirscher, M., Yartys, V.A., Baricco, M., Bellosta von Colbe, J., Blanchard, D., Bowman, R.C., Jr., Broom, D.P., Buckley, C.E., Chang, F., Chen, P., Cho, Y.W., Crivello, J.-C., Cuevas, F., David, W.I.F., de Jongh, P.E., Denys, R.V., Dornheim, M., Felderhoff, M., Filinchuk, Y., Froudakis, G.E., Grant, D.M., Gray, E.M., Hauback, B.C., He, T., Humphries, T.D., Jensen, T.R., Kim, S., Kojima, Y., Latroche, M., Li, H.-W., Lototskyy, M.V., Makepeace, J.W., Møller, K.T., Naheed, L., Ngene, P., Noréus, D., Nygård, M.M., Orimo, S.-I., Paskevicius, M., Pasquini, L., Ravnsbæk, D.B., Veronica Sofianos, M., Udovic, T.J., Vegge, T., Walker, G.S., Webb, C.J., Weidenthaler, C., Zlotea, C. %D 2020 %J Journal of Alloys and Compounds %P 153548 %R doi:10.1016/j.jallcom.2019.153548 %T Materials for hydrogen-based energy storage – past, recent progress and future outlook %U https://doi.org/10.1016/j.jallcom.2019.153548 %X Globally, the accelerating use of renewable energy sources, enabled by increased efficiencies and reduced costs, and driven by the need to mitigate the effects of climate change, has significantly increased research in the areas of renewable energy production, storage, distribution and end-use. Central to this discussion is the use of hydrogen, as a clean, efficient energy vector for energy storage. This review, by experts of Task 32, “Hydrogen-based Energy Storage” of the International Energy Agency, Hydrogen TCP, reports on the development over the last 6 years of hydrogen storage materials, methods and techniques, including electrochemical and thermal storage systems. An overview is given on the background to the various methods, the current state of development and the future prospects. The following areas are covered; porous materials, liquid hydrogen carriers, complex hydrides, intermetallic hydrides, electrochemical storage of energy, thermal energy storage, hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage. %0 journal article %@ 0360-3199 %A Bellosta von Colbe, J.M., Puszkiel, J., Capurso, G., Franz, A., Benz, H.U., Zoz, H., Klassen, T., Dornheim, M. %D 2019 %J International Journal of Hydrogen Energy %N 55 %P 29282-29290 %R doi:10.1016/j.ijhydene.2019.01.174 %T Scale-up of milling in a 100 L device for processing of TiFeMn alloy for hydrogen storage applications: Procedure and characterization %U https://doi.org/10.1016/j.ijhydene.2019.01.174 55 %X In this work, the mechanical milling of a FeTiMn alloy for hydrogen storage purposes was performed in an industrial milling device. The TiFe hydride is interesting from the technological standpoint because of the abundance and the low cost of its constituent elements Ti and Fe, as well as its high volumetric hydrogen capacity. However, TiFe is difficult to activate, usually requiring a thermal treatment above 400 °C. A TiFeMn alloy milled for just 10 min in a 100 L industrial milling device showed excellent hydrogen storage properties without any thermal treatment. The as-milled TiFeMn alloy did not need any activation procedure and showed fast kinetic behavior and good cycling stability. Microstructural and morphological characterization of the as-received and as-milled TiFeMn alloys revealed that the material presents reduced particle and crystallite sizes, even after such short time of milling. The refined microstructure of the as-milled TiFeMn is deemed to account for the improved hydrogen absorption-desorption properties. %0 journal article %@ 2075-4701 %A Jepsen, J., Capurso, G., Puszkiel, J., Busch, N., Werner, T., Milanese, C., Girella, A., Bellosta von Colbe, J., Dornheim, M., Klassen, T. %D 2019 %J Metals %N 3 %P 349 %R doi:10.3390/met9030349 %T Effect of the Process Parameters on the Energy Transfer during the Synthesis of the 2LiBH4-MgH2 Reactive Hydride Composite for Hydrogen Storage %U https://doi.org/10.3390/met9030349 3 %X Several different milling parameters (additive content, rotation velocity, ball-to-powder ratio, degree of filling, and time) affect the hydrogen absorption and desorption properties of a reactive hydride composite (RHC). In this paper, these effects were thoroughly tested and analyzed. The milling process investigated in such detail was performed on the 2LiH-MgB2 system doped with TiCl3. Applying an upgraded empirical model, the transfer of energy to the material during the milling process was determined. In this way, it is possible to compare the obtained experimental results with those from processes at different scales. In addition, the different milling parameters were evaluated independently according to their individual effect on the transferred energy. Their influence on the reaction kinetics and hydrogen capacity was discussed and the results were correlated to characteristics like particle and crystallite size, specific surface area, presence of nucleation sites and contaminants. Finally, an optimal value for the transferred energy was determined, above which the powder characteristics do not change and therefore the RHC system properties do not further improve. %0 journal article %@ 0360-3199 %A Bellosta von Colbe, J., Ares, J.-R., Barale, J., Baricco, M., Buckley, C., Capurso, G., Gallandat, N., Grant, D.M., Guzik, M.N., Jacob, I., Jensen, E.H., Jensen, T., Jepsen, J., Klassen, T., Lototskyy, M.V., Manickam, K., Montone, A., Puszkiel, J., Sartori, S., Sheppard, D.A., Stuart, A., Walker, G., Webb, C.J., Yang, H., Yartys, V., Zuettel, A., Dornheim, M. %D 2019 %J International Journal of Hydrogen Energy %N 15 %R doi:10.1016/j.ijhydene.2019.01.104 %T Application of hydrides in hydrogen storage and compression: Achievements, outlook and perspectives %U https://doi.org/10.1016/j.ijhydene.2019.01.104 15 %X In the frame of the “Hydrogen Storage Systems for Mobile and Stationary Applications” Group in the International Energy Agency (IEA) Hydrogen Task 32 “Hydrogen-based energy storage”, different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundred kg for use in hydrogen storage applications. %0 journal article %@ 1996-1073 %A Jepsen, J., Milanese, C., Puszkiel, J., Girella, A., Schiavo, B., Lozano, G.A., Capurso, G., Bellosta von Colbe, J.M., Marini, A., Kabelac, S., Dornheim, M., Klassen, T. %D 2018 %J Energies %N 5 %P 1081 %R doi:10.3390/en11051081 %T Fundamental Material Properties of the 2LiBH4-MgH2 Reactive Hydride Composite for Hydrogen Storage: (I) Thermodynamic and Heat Transfer Properties %U https://doi.org/10.3390/en11051081 5 %X Thermodynamic and heat transfer properties of the 2LiBH4-MgH2 composite (Li-RHC) system are experimentally determined and studied as a basis for the design and development of hydrogen storage tanks. Besides the determination and discussion of the properties, different measurement methods are applied and compared to each other. Regarding thermodynamics, reaction enthalpy and entropy are determined by pressure-concentration-isotherms and coupled manometric-calorimetric measurements. For thermal diffusivity calculation, the specific heat capacity is measured by high-pressure differential scanning calorimetry and the effective thermal conductivity is determined by the transient plane source technique and in situ thermocell. Based on the results obtained from the thermodynamics and the assessment of the heat transfer properties, the reaction mechanism of the Li-RHC and the issues related to the scale-up for larger hydrogen storage systems are discussed in detail. %0 journal article %@ 2075-4701 %A Puszkiel, J., Castro Riglos, M.V., Ramallo-Lopez, J.M., Mizrahi, M., Gemming, T., Pistidda, C., Larochette, P.A., Bellosta von Colbe, J., Klassen, T., Dornheim, M., Gennari, F. %D 2018 %J Metals %N 11 %P 967 %R doi:10.3390/met8110967 %T New Insight on the Hydrogen Absorption Evolution of the Mg–Fe–H System under Equilibrium Conditions %U https://doi.org/10.3390/met8110967 11 %X Mg2FeH6 is regarded as potential hydrogen and thermochemical storage medium due to its high volumetric hydrogen (150 kg/m3) and energy (0.49 kWh/L) densities. In this work, the mechanism of formation of Mg2FeH6 under equilibrium conditions is thoroughly investigated applying volumetric measurements, X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), and the combination of scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS) and high-resolution transmission electron microscopy (HR-TEM). Starting from a 2Mg:Fe stoichiometric powder ratio, thorough characterizations of samples taken at different states upon hydrogenation under equilibrium conditions confirm that the formation mechanism of Mg2FeH6 occurs from elemental Mg and Fe by columnar nucleation of the complex hydride at boundaries of the Fe seeds. The formation of MgH2 is enhanced by the presence of Fe. However, MgH2 does not take part as intermediate for the formation of Mg2FeH6 and acts as solid-solid diffusion barrier which hinders the complete formation of Mg2FeH6. This work provides novel insight about the formation mechanism of Mg2FeH6. %0 journal article %@ 1996-1073 %A Jepsen, J., Milanese, C., Puszkiel, J., Girella, A., Schiavo, B., Lozano, G.A., Capurso, G., Bellosta von Colbe, J.M., Marini, A., Kabelac, S., Dornheim, M., Klassen, T. %D 2018 %J Energies %N 5 %P 1170 %R doi:10.3390/en11051170 %T Fundamental Material Properties of the 2LiBH4-MgH2 Reactive Hydride Composite for Hydrogen Storage: (II) Kinetic Properties %U https://doi.org/10.3390/en11051170 5 %X Reaction kinetic behaviour and cycling stability of the 2LiBH4–MgH2 reactive hydride composite (Li-RHC) are experimentally determined and analysed as a basis for the design and development of hydrogen storage tanks. In addition to the determination and discussion about the properties; different measurement methods are applied and compared. The activation energies for both hydrogenation and dehydrogenation are determined by the Kissinger method and via the fitting of solid-state reaction kinetic models to isothermal volumetric measurements. Furthermore, the hydrogen absorption–desorption cycling stability is assessed by titration measurements. Finally, the kinetic behaviour and the reversible hydrogen storage capacity of the Li-RHC are discussed. %0 journal article %@ 1463-9076 %A Puszkiel, J.A., Castro Riglos, M.V., Karimi, F., Santoru, A., Pistidda, C., Klassen, T., Bellosta von Colbe, J.M., Dornheim, M. %D 2017 %J Physical Chemistry Chemical Physics %N 11 %P 7455-7460 %R doi:10.1039/C6CP08278E %T Changing the dehydrogenation pathway of LiBH4–MgH2 via nanosized lithiated TiO2 %U https://doi.org/10.1039/C6CP08278E 11 %X Nanosized lithiated titanium oxide (LixTiO2) noticeably improves the kinetic behaviour of 2LiBH4 + MgH2. The presence of LixTiO2 reduces the time required for the first dehydrogenation by suppressing the intermediate reaction to Li2B12H12, leading to direct MgB2 formation. %0 journal article %@ 0378-7753 %A Boerries, S., Metz, O., Pranzas, P.K., Bellosta von Colbe, J.M., Buecherl, T., Dornheim, M., Schreyer, A. %D 2016 %J Journal of Power Sources %P 567-577 %R doi:10.1016/j.jpowsour.2016.08.040 %T Optimization and comprehensive characterization of metal hydride based hydrogen storage systems using in-situ Neutron Radiography %U https://doi.org/10.1016/j.jpowsour.2016.08.040 %X For the storage of hydrogen, complex metal hydrides are considered as highly promising with respect to capacity, reversibility and safety. The optimization of corresponding storage tanks demands a precise and time-resolved investigation of the hydrogen distribution in scaled-up metal hydride beds. In this study it is shown that in situ fission Neutron Radiography provides unique insights into the spatial distribution of hydrogen even for scaled-up compacts and therewith enables a direct study of hydrogen storage tanks. A technique is introduced for the precise quantification of both time-resolved data and a priori material distribution, allowing inter alia for an optimization of compacts manufacturing process. For the first time, several macroscopic fields are combined which elucidates the great potential of Neutron Imaging for investigations of metal hydrides by going further than solely ’imaging’ the system: A combination of in-situ Neutron Radiography, IR-Thermography and thermodynamic quantities can reveal the interdependency of different driving forces for a scaled-up sodium alanate pellet by means of a multi-correlation analysis. A decisive and time-resolved, complex influence of material packing density is derived. The results of this study enable a variety of new investigation possibilities that provide essential information on the optimization of future hydrogen storage tanks. %0 journal article %@ 0947-8396 %A Capurso, G., Schiavo, B., Jepsen, J., Lozano, G., Metz, O., Saccone, A., de negri, S., Bellosta von Colbe, J.M., Klassen, T., Dornheim, M. %D 2016 %J Applied Physics A %N 3 %P 236 %R doi:10.1007/s00339-016-9771-x %T Development of a modular room-temperature hydride storage system for vehicular applications %U https://doi.org/10.1007/s00339-016-9771-x 3 %X The subject of this paper concerns the development of a vehicular hydrogen tank system, using a commercial interstitial metal hydride as storage material. The design of the tank was intended to feed a fuel cell in a light prototype vehicle, and the chosen hydride material, Hydralloy C5 by GfE, was expected to be able to absorb and desorb hydrogen in a range of pressure suitable for this purpose. A systematic analysis of the material in laboratory scale allows an extrapolation of the thermodynamic and reaction kinetics data. The following development of the modular tank was done according to the requirements of the prototype vehicle propulsion system and led to promising intermediate results. The modular approach granted flexibility in the design, allowing both to reach carefully the design goals and to learn the limiting factors in the sorption process. Proper heat management and suitable equipment remain key factors in order to achieve the best performances. %0 journal article %@ 0947-8396 %A Sheppard, D.A., Paskevicius, M., Humphries, T.D., Felderhoff, M., Capurso, G., Bellosta von Colbe, J., Dornheim, M., Klassem, T., Ward, P.A., Teprovich, J.A.Jr., Corgnale, C., Zidan, R., Grant, D.M., Buckley, C.E. %D 2016 %J Applied Physics A %N 4 %P 395 %R doi:10.1007/s00339-016-9825-0 %T Metal hydrides for concentrating solar thermal power energy storage %U https://doi.org/10.1007/s00339-016-9825-0 4 %X The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed. %0 journal article %@ 0378-7753 %A Puszkiel, J.A., Gennari, F.C., Larochette, P.A., Ramallo-Lopez, J.M., Vainio, U., Karimi, F., Pranzas, P.K., Troiani, H., Pistidda, C., Jepsen, J., Tolkiehn, M., Welter, E., Klassen, T., Bellosta von Colbe, J., Dornheim, M. %D 2015 %J Journal of Power Sources %P 606-616 %R doi:10.1016/j.jpowsour.2015.02.153 %T Effect of Fe additive on the hydrogenation-dehydrogenation properties of 2LiH + MgB2/2LiBH4 + MgH2 system %U https://doi.org/10.1016/j.jpowsour.2015.02.153 %X Lithium reactive hydride composite 2LiBH4 + MgH2 (Li-RHC) has been lately investigated owing to its potential as hydrogen storage medium for mobile applications. However, the main problem associated with this material is its sluggish kinetic behavior. Thus, aiming to improve the kinetic properties, in the present work the effect of the addition of Fe to Li-RHC is investigated. The addition of Fe lowers the starting decomposition temperature of Li-RHC about 30 °C and leads to a considerably faster isothermal dehydrogenation rate during the first hydrogen sorption cycle. Upon hydrogenation, MgH2 and LiBH4 are formed whereas Fe appears not to take part in any reaction. Upon the first dehydrogenation, the formation of nanocrystalline, well distributed FeB reduces the overall hydrogen storage capacity of the system. Throughout cycling, the agglomeration of FeB particles causes a kinetic deterioration. An analysis of the hydrogen kinetic mechanism during cycling shows that the hydrogenation and dehydrogenation behavior is influenced by the activity of FeB as heterogeneous nucleation center for MgB2 and its non-homogenous distribution in the Li-RHC matrix. %0 journal article %@ 0360-3199 %A Bellosta von Colbe, J.M., Lozano, G., Metz, O., Buecherl, T., Bormann, R., Klassen, T., Dornheim, M. %D 2015 %J International Journal of Hydrogen Energy %N 7 %P 2984-2988 %R doi:10.1016/j.ijhydene.2015.01.013 %T Design, sorption behaviour and energy management in a sodium alanate-based lightweight hydrogen storage tank %U https://doi.org/10.1016/j.ijhydene.2015.01.013 7 %X A lightweight tank for hydrogen storage based on four kilograms of sodium alanate was designed, built and tested. An improvement in gravimetric capacity of 83% and 49% in volumetric capacity over a previous tank [1] was achieved. Heat evolution and temperature spikes during hydrogen absorption were studied. Due to the high specific heat of the complex hydride, the storage material itself acts as a heat sink, aiding in the heat management of the system. The first-ever radiography with fast neutrons on an operational complex-hydride based test tank was performed. %0 journal article %@ 1369-7021 %A Ley, M.B., Jepsen, L.H., Lee, Y.-S., Cho, Y.W., Bellosta von Colbe, J.M., Dornheim, M., Rokni, M., jensen, J.O., Sloth, M., Filinchuk, Y., Joergensen, J.E., Besenbacher, F., Jensen, T.R. %D 2014 %J Materials Today %N 3 %P 122-128 %R doi:10.1016/j.mattod.2014.02.013 %T Complex hydrides for hydrogen storage – New perspectives %U https://doi.org/10.1016/j.mattod.2014.02.013 3 %X Since the 1970s, hydrogen has been considered as a possible energy carrier for the storage of renewable energy. The main focus has been on addressing the ultimate challenge: developing an environmentally friendly successor for gasoline. This very ambitious goal has not yet been fully reached, as discussed in this review, but a range of new lightweight hydrogen-containing materials has been discovered with fascinating properties. State-of-the-art and future perspectives for hydrogen-containing solids will be discussed, with a focus on metal borohydrides, which reveal significant structural flexibility and may have a range of new interesting properties combined with very high hydrogen densities. %0 journal article %@ 0378-7753 %A Puszkiel, J., Gennari, F.C., Larochette, P.A., Troiani, H.E., Karimi, F., Pistidda, C., Gosalawit-Utke, R., Jepsen, J., Jensen, T.R., Gundlach, C., Tolkiehn, M., Bellosta von Colbe, J., Klassen, T., Dornheim, M. %D 2014 %J Journal of Power Sources %P 799-811 %R doi:10.1016/j.jpowsour.2014.05.130 %T Hydrogen storage in Mg–LiBH4 composites catalyzed by FeF3 %U https://doi.org/10.1016/j.jpowsour.2014.05.130 %X Mg–10 mol% LiBH4 composite plus small amounts of FeF3 is investigated in the present work. The presence of LiBH4 during the milling process noticeably modifies the size and morphology of the Mg agglomerates, leading to faster hydrogenation and reaching almost the theoretical hydrogen capacity owing to enhanced hydrogen diffusion mechanism. However, the dehydrogenation of the system at low temperatures (≤300 °C) is still slow. Thus, FeF3 addition is proposed to improve the dehydrogenation kinetic behavior. From experimental results, it is found that the presence of FeF3 results in an additional size reduction of the Mg agglomerates between ∼10 and ∼100 μm and the formation of stable phases such as MgF2, LiF and FeB. The FeB species might have a catalytic effect upon the MgH2 decomposition. As a further result of the FeF3 addition, the Mg–10 mol%LiBH4–5 mol% FeF3 material shows improved dehydrogenation properties: reduced dehydrogenation activation energy, faster hydrogen desorption rate and reversible hydrogen capacities of about 5 wt% at 275 °C. %0 journal article %@ 0360-3199 %A Lozano, G.A., Bellosta von Colbe, J.M., Klassen, T., Dornheim, M. %D 2014 %J International Journal of Hydrogen Energy %N 33 %P 18952-18957 %R doi:10.1016/j.ijhydene.2014.09.035 %T Transport phenomena versus intrinsic kinetics: Hydrogen sorption limiting sub-process in metal hydride beds %U https://doi.org/10.1016/j.ijhydene.2014.09.035 33 %X This paper discusses and compares the different sub-processes that occur during the hydrogen sorption of practical systems based on metal hydrides, i.e. intrinsic kinetics, heat transfer and hydrogen transport. Derived from their modeling equations, a resistance analysis is developed on these hydrogen sorption sub-processes for the first time. This analysis allows quantifying how strongly each sub-process affects the overall sorption kinetics in a hydride bed and thereby the sorption-rate limiting sub-process can be identified. It was found that in the case of the hydrogen absorption of sodium alanate material the heat transfer resistance is the dominant and rate limiting sub-process, with the exception of small geometries. Besides, the resistance due to hydrogen transport is negligible in comparison to the overall absorption resistance. As a consequence, simulations and designs of scaled-up systems based on sodium alanate material always require heat transfer optimization as one of the foremost considerations. %0 journal article %@ 0360-3199 %A Bergemann, N., Pistidda, C., Milanese, C., Girella, A., Hansen, B.R.S., Wurr, J., Bellosta von Colbe, J., Jepsen, J., Jensen, T.R., Marini, A., Klassen, T., Dornheim, M. %D 2014 %J International Journal of Hydrogen Energy %N 18 %P 9877-9882 %R doi:10.1016/j.ijhydene.2014.02.025 %T NaAlH4 production from waste aluminum by reactive ball milling %U https://doi.org/10.1016/j.ijhydene.2014.02.025 18 %X Due to its thermodynamic properties and high reversibility, Ti doped sodium alanate is considered as a prototype hydrogen storage material. In this work we show how sodium alanate can be synthesized by reactive ball milling using aluminum particles obtained from recycled waste incineration slag. The synthesis was monitored with an in situ milling vial and characterized stepwise by PXD and DTA analyses. The sorption properties of the material were investigated using in situ synchrotron radiation PXD and volumetric analyses. A complete conversion of the starting reactants was obtained. %0 journal article %@ 0360-3199 %A Puszkiel, J., Gennari, F., Larochette, P.A., Karimi, F., Pistidda, C., Gosalawit-Utke, R., Jepsen, J., Jensen, T.R., Gundlach, C., Bellosta von Colbe, J., Klassen, T., Dornheim, M. %D 2013 %J International Journal of Hydrogen Energy %N 34 %P 14618-14630 %R doi:10.1016/j.ijhydene.2013.08.068 %T Sorption behavior of the MgH2–Mg2FeH6 hydride storage system synthesized by mechanical milling followed by sintering %U https://doi.org/10.1016/j.ijhydene.2013.08.068 34 %X The hydrogen sorption behavior of the Mg2FeH6–MgH2 hydride system is investigated via in-situ synchrotron and laboratory powder X-ray diffraction (SR-PXD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), particle size distribution (PSD) and volumetric techniques. The Mg2FeH6–MgH2 hydride system is obtained by mechanical milling in argon atmosphere followed by sintering at high temperature and hydrogen pressure. In-situ SR-PXD results show that upon hydriding MgH2 is a precursor for Mg2FeH6 formation and remained as hydrided phase in the obtained material. Diffusion constraints preclude the further formation of Mg2FeH6. Upon dehydriding, our results suggest that MgH2 and Mg2FeH6 decompose independently in a narrow temperature range between 275 and 300 °C. Moreover, the decomposition behavior of both hydrides in the Mg2FeH6–MgH2 hydride mixture is influenced by each other via dual synergetic-destabilizing effects. The final hydriding/dehydriding products and therefore the kinetic behavior of the Mg2FeH6–MgH2 hydride system exhibits a strong dependence on the temperature and pressure conditions. %0 journal article %@ 0360-3199 %A Jepsen, J., Milanese, C., Girella, A., Lozano, G.A., Pistidda, C., Bellosta von Colbe, J.M., Marini, A., Klassen, T., Dornheim, M. %D 2013 %J International Journal of Hydrogen Energy %N 20 %P 8357-8366 %R doi:10.1016/j.ijhydene.2013.04.090 %T Compaction pressure influence on material properties and sorption behaviour of LiBH4–MgH2 composite %U https://doi.org/10.1016/j.ijhydene.2013.04.090 20 %X Among different Reactive Hydride Composites (RHCs), the combination of LiBH4 and MgH2 is a promising one for hydrogen storage, providing a high reversible storage capacity. During desorption of both LiBH4 and MgH2, the formation of MgB2 lowers the overall reaction enthalpy. In this work, the material was compacted to pellets for further improvement of the volumetric hydrogen capacity. The influence of compaction pressure on the apparent density, thermal conductivity and sorption behaviour for the Li-based RHC during cycling was investigated for the first time. Although LiBH4 melts during cycling, decrepitation or disaggregation of the pellets is not observed for any of the investigated compaction pressures. However, a strong influence of the compaction pressure on the apparent hydrogen storage capacity is detected. The influence on the reaction kinetics is rather low. To provide explanations for the observed correlations, SEM analysis before and after each sorption step was performed for different compaction pressures. Thus, the low hydrogen sorption in the first cycles and the continuously improving sorption for low pressure compacted pellets with cycling may be explained by some surface observations, along with the form stability of the pellets. %0 journal article %@ 0360-3199 %A Jepsen, J., Bellosta von Colbe, J.M., Klassen, T., Dornheim, M. %D 2012 %J International Journal of Hydrogen Energy %N 5 %P 4204-4214 %R doi:10.1016/j.ijhydene.2011.11.141 %T Economic potential of complex hydrides compared to conventional hydrogen storage systems %U https://doi.org/10.1016/j.ijhydene.2011.11.141 5 %X Novel developments of materials for solid hydrogen storage show promising prospects. Complex hydrides exhibit great technical potential to store hydrogen in an efficient and safe way. Nevertheless, so far an evaluation of economic competitiveness is still lacking. In this work, an assessment about the economic feasibility of implementing complex hydrides as hydrogen storage materials is presented. The cost structure of hydrogen storage systems based on NaAlH4 and LiBH4/MgH2 is discussed and compared with the conventional high pressure (700 bar) and liquid storage systems. The vessel construction for the complex hydride systems is much simpler than for the alternative conventional methods because of the milder pressure and temperature conditions during the storage process. According to the economical analysis, this represents the main cost advantage of the complex hydride systems. %0 journal article %@ 0360-3199 %A Bellosta von Colbe, J.M., Metz, O., Lozano, G.A., Pranzas, K.P., Schmitz, H.W., Beckmann, F., Schreyer, A., Klassen, T., Dornheim, M. %D 2012 %J International Journal of Hydrogen Energy %N 3 %P 2807-2811 %R doi:10.1016/j.ijhydene.2011.03.153 %T Behavior of scaled-up sodium alanate hydrogen storage tanks during sorption %U https://doi.org/10.1016/j.ijhydene.2011.03.153 3 %X Sodium alanate is being experimentally tested in scaled-up quantities. For this purpose, several tanks have been designed and constructed. The tank functionality during absorption and desorption of hydrogen was demonstrated in a scale of 8 kg of alanate, with a peak technical absorption time below 10 min. The absorption and desorption data show good reproducibility. Neutron radiography was used in another tank to show the powder’s physical behavior during sorption, showing conservation of the macroscopic structure during cycling. %0 journal article %@ 0360-3199 %A Lozano, G.A., Na Ranong, C., Bellosta von Colbe, J.M., Bormann, R., Hapke, J., Fieg, G., Klassen, T., Dornheim, M. %D 2012 %J International Journal of Hydrogen Energy %N 3 %P 2825-2834 %R doi:10.1016/j.ijhydene.2011.03.043 %T Optimization of hydrogen storage tubular tanks based on light weight hydrides %U https://doi.org/10.1016/j.ijhydene.2011.03.043 3 %X Design of hydrogen storage systems aims at minimal weight and volume while fulfilling performance criteria. In this paper, the tubular tank configuration for hydrogen storage based on light weight hydrides is optimized towards its total weight using the predictions of a newly developed simulation model. Sodium alanate is taken as model material. A clear definition of the optimization is presented, stating a new optimization criterion: a defined total mass of hydrogen has to be charged in a given time, instead of prescribing percentages of the total hydrogen storage capacity. This yields a wider space of possible solutions. The effects of material compaction, addition of expanded graphite and different tubular tank diameters were evaluated. It was found that compaction of the material is the most influential factor to optimize the storage system. In order to obtain lighter storage systems one should concentrate on improving the ratio mass of hydride bed to mass of tank wall by screening lighter materials for the tank wall and developing hydrogen storage materials exhibiting both higher gravimetric and volumetric storage capacities. %0 journal article %@ 1932-7447 %A Suarez Alcantara, K., Ramallo Lopez, J.M., Boesenberg, U., Saldan, I., Pistidda, C., Requejo, F.G., Jensen, T., Cerenius, Y., Soerby, M., Avila, J., Bellosta von Colbe, J., Taube, K., Klassen, T., Dornheim, M. %D 2012 %J The Journal of Physical Chemistry C %N 12 %P 7207-7212 %R doi:10.1021/jp211620h %T 3CaH2 + 4MgB2 + CaF2 Reactive Hydride Composite as a Potential Hydrogen Storage Material: Hydrogenation and Dehydrogenation Pathway %U https://doi.org/10.1021/jp211620h 12 %X A reactive hydride composite (RHC) with initial composition 3CaH2 + 4MgB2 + CaF2 was studied by in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and X-ray absorption near edge structure (XANES) at the B K-edge and at the Ca K-edge. The hydrogenation reaction proceeds by an unknown intermediate. No evidence of intermediates was observed during the dehydrogenation reaction. B and Ca K-edge XANES results hint to a closed interaction of CaF2 and Ca(BH4)2. The main function of CaF2 in the 3CaH2 + 4MgB2 + CaF2 RHC is as a dopant for the hydrogenation and dehydrogenation reactions. %0 journal article %@ 0360-3199 %A Saldan, I., Ramallo-Lopez, J.M., Requejo, F.G., Suarez-Alcantara, K., Bellosta von Colbe, J., Avila, J. %D 2012 %J International Journal of Hydrogen Energy %N 13 %P 10236-10239 %R doi:10.1016/j.ijhydene.2012.04.010 %T NEXAFS study of 2LiF–MgB2 composite %U https://doi.org/10.1016/j.ijhydene.2012.04.010 13 %X First results of Near Edge X-ray Absorption Fine Structure (NEXAFS) at the B K-edge (193 eV) for LiF–MgB2 composite with molar ratio (2:1) are presented. Obtained results indicate a formation of mixed borohydrides/borofluorides of the type of LiBH4−xFx, thus suggesting fluorine substituting for hydrogen. %0 journal article %@ 0009-2509 %A Na Ranong, C., Lozano, G., Hapke, J., Roetzel, W., Fieg, G., Bellosta von Colbe, J. %D 2011 %J Chemical Engineering Science %N 20 %P 4654-4662 %R doi:10.1016/j.ces.2011.06.021 %T Application of Danckwerts-type boundary conditions to the modeling of the thermal behavior of metal hydride reactors %U https://doi.org/10.1016/j.ces.2011.06.021 20 %X The paper presents a model-based investigation of a metal hydride reactor applied as a solid state hydrogen storage device. The elements of a metal hydride reactor are hydrogen supply duct, internal hydrogen distribution, hydride bed, reactor shell and the flow domain of the heat transfer fluid. Internal hydrogen distribution and hydride bed are porous media. Therefore, hydrogen flows through non-porous and porous regions during its reversible exothermic absorption and endothermic desorption, respectively. The interface between porous and non-porous regions is a discontinuity with respect to energy transport mechanisms. Hence, Danckwerts-type boundary conditions for the energy balance equation are introduced. Application of the first and second law of thermodynamics to the interface reveals that temperature jumps may occur at the hydrogen inlet but are not allowed at the hydrogen outlet. Exemplarily the loading behavior of a metal hydride storage tank based on sodium alanate is analyzed. It is demonstrated and experimentally validated that only Danckwerts-type boundary conditions predict the important cooling effect of the inlet hydrogen on the exothermic absorption process correctly. %0 journal article %@ 0022-4596 %A Suarez Alcantara, K., Boesenberg, U., Zavorotynska, O., Bellosta von Colbe, J., Taube, K., Baricco, M., Klassen, T., Dornheim, M. %D 2011 %J Journal of Solid State Chemistry %N 11 %P 3104-3109 %R doi:10.1016/j.jssc.2011.09.019 %T Sorption and desorption properties of a CaH2/MgB2/CaF2 reactive hydride composite as potential hydrogen storage material %U https://doi.org/10.1016/j.jssc.2011.09.019 11 %X The hydrogenation behavior of 3CaH2+4MgB2+CaF2 composite was studied by manometric measurements, powder X-ray diffraction, differential scanning calorimetry and attenuated total reflection infrared spectroscopy. The maximum observed quantity of hydrogen loaded in the composite was 7.0 wt%. X-ray diffraction showed the formation of Ca(BH4)2 and MgH2 after hydrogenation. The activation energy for the dehydrogenation reaction was evaluated by DSC measurements and turns out to be 162±15 kJ mol−1 H2. This value decreases due to cycling to 116±5 kJ mol−1 H2 for the third dehydrogenation step. A decrease of ca. 25–50 °C in dehydrogenation temperature was observed with cycling. Due to its high capacity and reversibility, this composite is a promising candidate as a potential hydrogen storage material. %0 journal article %@ 0378-7753 %A Lozano, G.A., Bellosta von Colbe, J.M., Bormann, R., Klassen, T., Dornheim, M. %D 2011 %J Journal of Power Sources %N 22 %P 9254-9259 %R doi:10.1016/j.jpowsour.2011.07.053 %T Enhanced volumetric hydrogen density in sodium alanate by compaction %U https://doi.org/10.1016/j.jpowsour.2011.07.053 22 %X Powder compaction is a potential process for the enhancement of the volumetric and gravimetric capacities of hydrogen storage systems based on metal hydrides. This paper presents the hydrogen absorption and desorption behaviour of compacts of sodium alanate material prepared under different levels of compaction pressure. It is shown that even at high compaction levels and low initial porosities, hydrogen absorption and desorption kinetics can proceed comparatively fast in compacted material. Furthermore, experimental hydrogen weight capacities of compacted material are higher than the experimental values obtained in case of loose powder. It is demonstrated that the kinetic behaviour of the compacted material during cycling is directly associated to the volumetric expansion of the compact, which is quantitatively measured and analyzed during both hydrogen absorption and desorption processes. The cycling behaviour and dimensional changes of compacted sodium alanate material are a key consideration point if it is used as hydrogen storage materials in practical tank systems. %0 journal article %@ 1932-7447 %A Gosalawit-Utke, R., Suarez, K., Bellosta von Colbe, J.M., Boesenberg, U., Jensen, T.R., Cerenius, Y., Bonatto Minella, C., Pistidda, C., Barkhordarian, G., Schulze, M., Klassen, T., Bormann, R., Dornheim, M. %D 2011 %J The Journal of Physical Chemistry C %N 9 %P 3762-3768 %R doi:10.1021/jp108236e %T Ca(BH4)2−MgF2 Reversible Hydrogen Storage: Reaction Mechanisms and Kinetic Properties %U https://doi.org/10.1021/jp108236e 9 %X A composite of Ca(BH4)2−MgF2 is proposed as a reversible hydrogen storage system. The dehydrogenation and rehydrogenation reaction mechanisms are investigated by in situ time-resolved synchrotron radiation powder X-ray diffraction (SR-PXD) and Raman spectroscopy. The formation of an intermediate phase (CaF2−xHx) is observed during rehydrogenation. The hydrogen content of 4.3 wt % is obtained within 4 h during the first dehydrogenation at isothermal and isobaric conditions of 330 °C and 0.5 bar H2, respectively. The cycling efficiency is evaluated by three release and uptake cycles together with absorbed hydrogen content in the range 5.1−5.8 wt % after 2.5 h (T = 330 °C and p(H2) = 130 bar). The kinetic properties on the basis of hydrogen absorption are comparable for all cycles. As compared to pure Ca(BH4)2 and Ca(BH4)2−MgH2 composite, Ca(BH4)2−MgF2 composite reveals the kinetic destabilization and the reproducibility of hydrogen storage capacities during cycling, respectively. %0 journal article %@ 1932-7447 %A Gosalawit-Utke, R., Bellosta von Colbe, J.M., Dornheim, M., Jensen, T.R., Cerenius, Y., Bonatto Minella, C., Peschke, M., Bormann, R. %D 2010 %J The Journal of Physical Chemistry C %N 22 %P 10291-10296 %R doi:10.1021/jp910266m %T LiF−MgB2 System for Reversible Hydrogen Storage %U https://doi.org/10.1021/jp910266m 22 %X LiF−MgB2 composites are proposed for reversible hydrogen storage. With respect to pure LiBH4, a significantly kinetic destabilization regarding hydrogenation and dehydrogenation is accomplished. The reversible hydrogen storage capacity is up to 6.4 wt %. The kinetic properties are improved significantly during cycling. The formations of the hydridofluoride phases (LiBH4−yFy and LiH1−xFx) are observed by in situ synchrotron X-ray diffraction (XRD) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Hydrogenation and dehydrogenation mechanisms are described on the basis of the formation and decomposition of the hydridofluoride phases, respectively. %0 journal article %@ 0360-3199 %A Lozano, G.A., Na Ranong, C., Bellosta von Colbe, J.M., Bormann, R., Fieg, G., Hapke, J., Dornheim, M. %D 2010 %J International Journal of Hydrogen Energy %N 14 %P 7539-7546 %R doi:10.1016/j.ijhydene.2010.04.142 %T Empirical kinetic model of sodium alanate reacting system (II). Hydrogen desorption %U https://doi.org/10.1016/j.ijhydene.2010.04.142 14 %X Simulation and design of hydrogen storage systems based on metal hydrides require appropriate quantitative kinetic description. This paper presents an empirical kinetic model for the two-step hydrogen desorption of sodium alanate material doped with aluminium-reduced TiCl4, produced in kg-scale. The model is based on kinetic data obtained by volumetric titration measurements within a range of experimental conditions varying from 0 bar to 35 bar and from 100 °C to 190 °C. It is shown that while the first desorption step is a zero-order reaction, the second desorption step follows the Johnson–Mehl–Avrami (JMA) equation with n = 1. The predictions of the model are validated by experimental results and are used to asses the pressure–temperature (p–T) performance of the desorption steps against selected hydrogen supply criteria. This paper complements a previous paper of this investigation that presented the kinetic model of the corresponding hydrogen absorption of sodium alanate material. %0 journal article %@ 0360-3199 %A Lozano, G.A., Na Ranong, C., Bellosta von Colbe, J.M., Bormann, R., Fieg, G., Hapke, J., Dornheim, M. %D 2010 %J International Journal of Hydrogen Energy %N 13 %P 6763-6772 %R doi:10.1016/j.ijhydene.2010.04.080 %T Empirical kinetic model of sodium alanate reacting system (I). Hydrogen absorption %U https://doi.org/10.1016/j.ijhydene.2010.04.080 13 %X Hydrogen storage systems based on metal hydrides require appropriate quantitative kinetic description for simulations and designs, in particular for the crucial absorption process. This investigation proposes an empirical kinetic model for the hydrogen absorption of sodium alanate material doped with aluminium-reduced TiCl4, produced in kg-scale. The model is based on kinetic data obtained by volumetric titration measurements performed on each of the two absorption steps of sodium alanate, within a range of experimental conditions varying from 10 bar to 110 bar and from 100 °C to 180 °C. It is shown that each step is best described by the JMA model with n = 1.33. The kinetic equations are implemented in a mass balance and used to predict the reaction rate of the two steps of hydrogen absorption. Even when they proceed simultaneously, the predictions agree well with experimental results. The second paper of this investigation presents the results for the kinetic model of the corresponding hydrogen desorption. %0 journal article %@ 1359-6454 %A Boesenberg, U., Kim, J.W., Gosslar, D., Eigen, N., Jensen, T.R., Bellosta von Colbe, J.M., Zhou, Y., Dahms, M., Kim, D.H., Guenther, R., Cho, Y.W., Oh, K.H., Klassen, T., Bormann, R., Dornheim, M. %D 2010 %J Acta Materialia %N 9 %P 3381-3389 %R doi:10.1016/j.actamat.2010.02.012 %T Role of Additives in LiBH4-MgH2 Reactive Hydride Composite sorption reactions %U https://doi.org/10.1016/j.actamat.2010.02.012 9 %X The influence of additives on the reaction kinetics and microstructure refinement in LiBH4–MgH2 composites is investigated in detail. Indications of the rate-limiting processes during the reactions are obtained by comparison of the measured reaction kinetics with simulations with one specific rate-limiting process. The kinetics of the sorption reactions are derived from volumetric measurements as well as from in situ X-ray diffraction measurements. During desorption, the hydrogen is released at a constant rate, which is possibly correlated with the one-dimensional growth of MgB2 platelets. In contrast, the kinetic curves of the absorption reactions exhibit the typical shape of contracting-volume controlled kinetics. The microscopical interpretation of kinetic measurements are supported by transmission electron microscopy images confirming the formation of additive-nanostructures in the grain boundaries upon cycling. The present investigations underline the importance of the additives as nucleation substrates and the influence of microstructure on the reaction kinetics. %0 journal article %@ 0925-8388 %A Eigen, N., Boesenberg, U., Bellosta von Colbe, J., Jensen, T., Cerenius, Y., Dornheim, M., Klassen, T., Bormann, R. %D 2009 %J Journal of Alloys and Compounds %N 1-2 %P 76-80 %R doi:10.1016/j.jallcom.2008.10.002 %T Reversible hydrogen storage in NaF–Al composites %U https://doi.org/10.1016/j.jallcom.2008.10.002 1-2 %X This work demonstrates that hydrogen can be reversibly stored in a composite of NaF and Al. NaF and Al reacts to a mixture of Na3AlF6 and NaAlH4 via hydridofluoride phases of the form Na3AlH6−xFx. The analysis of thermodynamics based on literature standard enthalpies of formation yields the technically favourable enthalpy of reaction of roughly 35 kJ/mol H2 for a theoretical gravimetric hydrogen storage capacity of 3.3 wt%. Reaction mechanisms are discussed with respect to substitution of hydrogen by fluorine in complex hydrides. %0 journal article %@ 0930-7516 %A Na Ranong, C., Hoehne, M., Franzen, J., Hapke, J., Fieg, G., Dornheim, M., Eigen, M., Bellosta von Colbe, J., Metz, O. %D 2009 %J Chemical Engineering and Technology %N 8 %P 1154-1163 %R doi:10.1002/ceat.200900095 %T Concept, Design and Manufacture of a Prototype Hydrogen Storage Tank Based on Sodium Alanate %U https://doi.org/10.1002/ceat.200900095 8 %X In the framework of the EC project STORHY (Hydrogen Storage for Automotive Applications), the prototype of a solid storage tank for hydrogen based on sodium alanate was developed. A storage tank containing 8 kg sodium alanate was designed and manufactured with the objective of fast refueling. To obtain the optimum design of the storage tank a simulation tool was developed and validated by experiments with a laboratory-scale tubular reactor. Application of the simulation tool to different storage concepts and geometries yielded the final design. The chosen concept is modular, enabling simple scale-up. This is the basis for the future development of fuel cell vehicle storage tanks containing 5 kg of hydrogen. %0 journal article %@ 0957-4484 %A Boesenberg, U., Vainio, U., Pranzas, P.K., Bellosta von Colbe, J.M., Goerigk, G., Welter, E., Dornheim, M., Schreyer, A., Bormann, R. %D 2009 %J Nanotechnology %N 20 %P 204003 %R doi:10.1088/0957-4484/20/20/204003 %T On the chemical state and distribution of Zr- and V-based additives in reactive hydride composites %U https://doi.org/10.1088/0957-4484/20/20/204003 20 %X Reactive hydride composites (RHCs) are very promising hydrogen storage materials for future applications due to their reduced reaction enthalpies and high gravimetric capacities. At present, the materials' functionality is limited by the reaction kinetics. A significant positive influence can be observed with addition of transition-metal-based additives. To understand the effect of these additives, the chemical state and changes during the reaction as well as the microstructural distribution were investigated using x-ray absorption near-edge structure (XANES) spectroscopy and anomalous small-angle x-ray scattering (ASAXS). In this work, zirconium- and vanadium-based additives were added to 2LiBH4–MgH2 composites and 2LiH–MgB2 composites and measured in the vicinity of the corresponding absorption edge. The measurements reveal the formation of finely distributed zirconium diboride and vanadium-based nanoparticles. The potential mechanisms for the observed influence on the reaction kinetics are discussed. %0 journal article %@ 1932-7447 %A Corey, R.L., Ivancic, T.M., Shane, D.T., Carl, E.A., Bowman, R.C., Bellosta von Colbe, J.M., Dornheim, M., Bormann, R., Huot, J., Zidan, R., Stowe, A.C., Conradi, M.S. %D 2008 %J The Journal of Physical Chemistry C %N 49 %P 19784-19790 %R doi:10.1021/jp807900r %T Hydrogen Motion in Magnesium Hydride by NMR %U https://doi.org/10.1021/jp807900r 49 %X In coarse-grained MgH2, the diffusive motion of hydrogen remains too slow (<105 hops s−1) to narrow the H NMR line up to 400 °C. Slow-motion dipolar relaxation time T1D measurements reveal the motion, with hopping rate ωH from 0.1 to 430 s−1over the range of 260 to 400 °C, the first direct measurement of H hopping in MgH2. The ωH data are described by an activation energy of 1.72 eV (166 kJ/mol) and attempt frequency of 2.5 × 1015 s−1. In ball-milled MgH2 with 0.5 mol % added Nb2O5 catalyst, line-narrowing is evident already at 50 °C. The line shape shows distinct broad and narrow components corresponding to immobile and mobile H, respectively. The fraction of mobile H grows continuously with temperature, reaching ∼30% at 400 °C. This demonstrates that this material’s superior reaction kinetics are due to an increased rate of H motion, in addition to the shorter diffusion paths from ball-milling. In ball-milled MgH2 without additives, the line-narrowed component is weaker and is due, at least in part, to trapped H2 gas. The spin−lattice relaxation rates T1−1 of all materials are compared, with ball-milling markedly increasing T1−1. The weak temperature dependence of T1−1 suggests a mechanism with paramagnetic relaxation centers arising from the mechanical milli