%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 %N %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 %@ 0925-8388 %A Warfsmann, J.,Puszkiel, J.A.,Passing, M.,Krause, P.S.,Wienken, E.,Taube, K.,Klassen, T.,Pistidda, C.,Jepsen, J. %D 2023 %J Journal of Alloys and Compounds %N %P 169814 %R doi:10.1016/j.jallcom.2023.169814 %T Applying wash coating techniques for swelling-induced stress reduction and thermal improvement in metal hydrides %U https://doi.org/10.1016/j.jallcom.2023.169814 %X The storage of hydrogen in metal alloys as an alternative to hydrogen storage in pressurized or liquid form has the advantage of high volumetric storage capacity and less complex storage systems due to lower pressure and moderate temperature conditions. The later leads to an improved safety and reduced cost of the storage vessel. However, when considering their utilization in hydrogen storage tanks, swelling-induced stress and heat management are challenges that still require to be addressed. Several strategies have been published in the past to address these problems, however it can be challenging to scale them up. In this work, we propose an easily scalable approach to overcome these drawbacks. The commercially available AB2 room-temperature metal alloy Hydralloy C5 was modified by applying a wash coating-like methodology. The surface of the metal alloy was coated with a mixture of a conductive material like expanded natural graphite (ENG) or aluminum and the elastomeric ethylene-vinyl acetate copolymer (EVA). The performance of this modified metal alloy was investigated by in situ measurement of hydrogen capacity, heat dissipation and swelling-induced stress during 50 hydrogenation/dehydrogenation cycles. The coated metal alloy maintained a satisfactory hydrogen capacity with slightly improved heat dissipation. The swelling-induced stress behavior of the treated material was greatly improved. Especially the addition of a mixture of 10 wt% ENG and 10 wt% EVA allowed to completely compensate for the swelling-induced stress during hydrogenation. %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 Shang, Y.,Jin, O.,Puszkiel, J.,Karimi, F.,Dansirima, P.,Sittiwet, C.,Utke, R.,Soontaranon, S.,Le, T.,Gizer, G.,Szabó, D.,Wagner, S.,Kübel, C.,Klassen, T.,Dornheim, M.,Pundt, A.,Pistidda, C. %D 2022 %J International Journal of Hydrogen Energy %N 89 %P 37882-37894 %R doi:10.1016/j.ijhydene.2022.08.293 %T Effects of metal-based additives on dehydrogenation process of 2NaBH4 + MgH2 system %U https://doi.org/10.1016/j.ijhydene.2022.08.293 89 %X We report a systematic investigation of the effect that selected metal-based additives have on the dehydrogenation properties of the reactive hydride composite (RHC) model system 2NaBH4+MgH2. Compared to the pristine system, the material doped with 3TiCl3·AlCl3 exhibits superior dehydrogenation kinetics. The addition of 3TiCl3·AlCl3 alters the controlling mechanism of the second dehydrogenation step making it change from a two-dimensional interface controlled process to a two-dimensional nucleation and growth controlled process. The microstructural investigation of the dehydrogenated 2NaBH4+MgH2 via high-resolution transmission electron microscopy (HRTEM) shows significant differences in the MgB2 morphology formed in the doped and undoped systems. The MgB2 has a needle-like structure in the sample doped with 3TiCl3·AlCl3, which is different from the plate-like MgB2 structure in the undoped sample. Moreover, nanostructured metal-based phases, such as TiB2/AlB2 particles, acting as heterogeneous nucleation sites for MgB2 are also identified for the sample doped with 3TiCl3·AlCl3. %0 journal article %@ 0022-2461 %A Gizer, G.,Karimi, F.,Pistidda, C.,Cao, H.,Puszkiel, J.,Shang, Y.,Gericke, E.,Hoell, A.,Pranzas, K.,Klassen, T.,Dornheim, M. %D 2022 %J Journal of Materials Science %N 22 %P 10028-10038 %R doi:10.1007/s10853-022-06985-4 %T Effect of the particle size evolution on the hydrogen storage performance of KH doped Mg(NH2)2 + 2LiH %U https://doi.org/10.1007/s10853-022-06985-4 22 %X In recent years, many solid-state hydride-based materials have been considered as hydrogen storage systems for mobile and stationary applications. Due to a gravimetric hydrogen capacity of 5.6 wt% and a dehydrogenation enthalpy of 38.9 kJ/mol H2, Mg(NH2)2 + 2LiH is considered a potential hydrogen storage material for solid-state storage systems to be coupled with PEM fuel cell devices. One of the main challenges is the reduction of dehydrogenation temperature since this system requires high dehydrogenation temperatures (~ 200 °C). The addition of KH to this system significantly decreases the dehydrogenation onset temperature to 130 °C. On the one hand, the addition of KH stabilizes the hydrogen storage capacity. On the other hand, the capacity is reduced by 50% (from 4.1 to 2%) after the first 25 cycles. In this work, the particle sizes of the overall hydride matrix and the potassium-containing species are investigated during hydrogen cycling. Relation between particle size evolution of the additive and hydrogen storage kinetics is described by using an advanced synchrotron-based technique: Anomalous small-angle X-ray scattering, which was applied for the first time at the potassium K-edge for amide-hydride hydrogen storage systems. The outcomes from this investigation show that, the nanometric potassium-containing phases might be located at the reaction interfaces, limiting the particle coarsening. Average diameters of potassium-containing nanoparticles double after 25 cycles (from 10 to 20 nm). Therefore, reaction kinetics at subsequent cycles degrade. The deterioration of the reaction kinetics can be minimized by selecting lower absorption temperatures, which mitigates the particle size growth, resulting in two times faster reaction kinetics. %0 journal article %@ 1996-1073 %A Dreistadt, D.M.,Puszkiel, J.,von Colbe, J.M.B.,Capurso, G.,Steinebach, G.,Meilinger, S.,Le, T.-T.,Guarneros, M.C.,Klassen, T.,Jepsen, J. %D 2022 %J Energies %N 3 %P 844 %R doi:10.3390/en15030844 %T A Novel Emergency Gas-to-Power System Based on an Efficient and Long-Lasting Solid-State Hydride Storage System: Modeling and Experimental Validation %U https://doi.org/10.3390/en15030844 3 %X In this paper, a gas-to-power (GtoP) system for power outages is digitally modeled and experimentally developed. The design includes a solid-state hydrogen storage system composed of TiFeMn as a hydride forming alloy (6.7 kg of alloy in five tanks) and an air-cooled fuel cell (maximum power: 1.6 kW). The hydrogen storage system is charged under room temperature and 40 bar of hydrogen pressure, reaching about 110 g of hydrogen capacity. In an emergency use case of the system, hydrogen is supplied to the fuel cell, and the waste heat coming from the exhaust air of the fuel cell is used for the endothermic dehydrogenation reaction of the metal hydride. This GtoP system demonstrates fast, stable, and reliable responses, providing from 149 W to 596 W under different constant as well as dynamic conditions. A comprehensive and novel simulation approach based on a network model is also applied. The developed model is validated under static and dynamic power load scenarios, demonstrating excellent agreement with the experimental results. %0 journal article %@ 1438-1656 %A Karimi, F.,Börris, S.,Pranzas, P.,Metz, O.,Hoell, A.,Gizer, G.,Puszkiel, J.,Riglos, M.,Pistidda, C.,Dornheim, M.,Klassen, T.,Schreyer, A. %D 2021 %J Advanced Engineering Materials %N 11 %P 2100294 %R doi:10.1002/adem.202100294 %T Characterization of LiBH4–MgH2 Reactive Hydride Composite System with Scattering and Imaging Methods Using Neutron and Synchrotron Radiation %U https://doi.org/10.1002/adem.202100294 11 %X Reversible solid-state hydrogen storage in metal hydrides is a key technology for pollution-free energy conversion systems. Herein, the LiBH2–MgH2 composite system with and without ScCl3 additive is investigated using synchrotron- and neutron-radiation-based probing methods that can be applied to characterize such lightweight metal–hydrogen systems from nanoscopic levels up to macroscopic scale. Combining the results of neutron- and photon-based methods allows a complementary insight into reaction paths and mechanisms, complex interactions between the hydride matrix and additive, hydrogen distribution, material transport, structural changes, and phase separation in the hydride matrix. The gained knowledge is of great importance for development and optimization of such novel metal-hydride-based hydrogen storage systems with respect to future applications. %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 %@ 2046-2069 %A Karimi, F.,Pranzas, K.,Puszkiel, J.,Castro Riglos, V.,Milanese, C.,Vainio, U.,Pistidda, C.,Gizer, G.,Klassen, T.,Schreyer, A.,Dornheim, M. %D 2021 %J RSC Advances %N 37 %P 23122-23135 %R doi:10.1039/D1RA03246A %T A comprehensive study on lithium-based reactive hydride composite (Li-RHC) as a reversible solid-state hydrogen storage system toward potential mobile applications %U https://doi.org/10.1039/D1RA03246A 37 %X Reversible solid-state hydrogen storage is one of the key technologies toward pollutant-free and sustainable energy conversion. The composite system LiBH4–MgH2 can reversibly store hydrogen with a gravimetric capacity of 13 wt%. However, its dehydrogenation/hydrogenation kinetics is extremely sluggish (∼40 h) which hinders its usage for commercial applications. In this work, the kinetics of this composite system is significantly enhanced (∼96%) by adding a small amount of NbF5. The catalytic effect of NbF5 on the dehydrogenation/hydrogenation process of LiBH4–MgH2 is systematically investigated using a broad range of experimental techniques such as in situ synchrotron radiation X-ray powder diffraction (in situ SR-XPD), X-ray absorption spectroscopy (XAS), anomalous small angle X-ray scattering (ASAXS), and ultra/small-angle neutron scattering (USANS/SANS). The obtained results are utilized to develop a model that explains the catalytic function of NbF5 in hydrogen release and uptake in the LiBH4–MgH2 composite system. %0 journal article %@ 1996-1073 %A Le, T.-T.,Pistidda, C.,Puszkiel, J.,Riglos, M.V.C.,Dreistadt, D.M.,Klassen, T.,Dornheim, M. %D 2021 %J Energies %N 23 %P 7853 %R doi:10.3390/en14237853 %T Enhanced Hydrogen Storage Properties of Li-RHC System with In-House Synthesized AlTi3 Nanoparticles %U https://doi.org/10.3390/en14237853 23 %X In recent years, the use of selected additives for improving the kinetic behavior of the system 2LiH + MgB2 (Li-RHC) has been investigated. As a result, it has been reported that some additives (e.g., 3TiCl3·AlCl3), by reacting with the Li-RHC components, form nanostructured phases (e.g., AlTi3) possessing peculiar microstructural properties capable of enhancing the system’s kinetic behavior. The effect of in-house-produced AlTi3 nanoparticles on the hydrogenation/dehydrogenation kinetics of the 2LiH + MgB2 (Li-RHC) system is explored in this work, with the aim of reaching high hydrogen storage performance. Experimental results show that the AlTi3 nanoparticles significantly improve the reaction rate of the Li-RHC system, mainly for the dehydrogenation process. The observed improvement is most likely due to the similar structural properties between AlTi3 and MgB2 phases which provide an energetically favored path for the nucleation of MgB2. In comparison with the pristine material, the Li-RHC doped with AlTi3 nanoparticles has about a nine times faster dehydrogenation rate. The results obtained from the kinetic modeling indicate a change in the Li-RHC hydrogenation reaction mechanism in the presence of AlTi3 nanoparticles. %0 journal article %@ 1996-1944 %A Le, T.-T.,Pistidda, C.,Abetz, C.,Georgopanos, P.,Garroni, S.,Capurso, G.,Milanese, C.,Puszkiel, J.,Dornheim, M.,Abetz, V.,Klassen, T. %D 2020 %J Materials %N 4 %P 991 %R doi:10.3390/ma13040991 %T Enhanced Stability of Li-RHC Embedded in an Adaptive TPX™ Polymer Scaffold %U https://doi.org/10.3390/ma13040991 4 %X In this work, the possibility of creating a polymer-based adaptive scaffold for improving the hydrogen storage properties of the system 2LiH+MgB2+7.5(3TiCl3·AlCl3) was studied. Because of its chemical stability toward the hydrogen storage material, poly(4-methyl-1-pentene) or in-short TPXTM was chosen as the candidate for the scaffolding structure. The composite system was obtained after ball milling of 2LiH+MgB2+7.5(3TiCl3·AlCl3) and a solution of TPXTM in cyclohexane. The investigations carried out over the span of ten hydrogenation/de-hydrogenation cycles indicate that the material containing TPXTM possesses a higher degree of hydrogen storage stability. %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 %@ 2045-2322 %A Gizer, G.,Puszkiel, J.,Riglos, M.,Pistidda, C.,Ramallo-López, J.,Mizrahi, M.,Santoru, A.,Gemming, T.,Tseng, J.,Klassen, T.,Dornheim, M. %D 2020 %J Scientific Reports %N %P 8 %R doi:10.1038/s41598-019-55770-y %T Improved kinetic behaviour of Mg(NH2)2-2LiH doped with nanostructured K-modified-LixTiyOz for hydrogen storage %U https://doi.org/10.1038/s41598-019-55770-y %X The system Mg(NH2)2 + 2LiH is considered as an interesting solid-state hydrogen storage material owing to its low thermodynamic stability of ca. 40 kJ/mol H2 and high gravimetric hydrogen capacity of 5.6 wt.%. However, high kinetic barriers lead to slow absorption/desorption rates even at relatively high temperatures (>180 °C). In this work, we investigate the effects of the addition of K-modified LixTiyOz on the absorption/desorption behaviour of the Mg(NH2)2 + 2LiH system. In comparison with the pristine Mg(NH2)2 + 2LiH, the system containing a tiny amount of nanostructured K-modified LixTiyOz shows enhanced absorption/desorption behaviour. The doped material presents a sensibly reduced (∼30 °C) desorption onset temperature, notably shorter hydrogen absorption/desorption times and reversible hydrogen capacity of about 3 wt.% H2 upon cycling. Studies on the absorption/desorption processes and micro/nanostructural characterizations of the Mg(NH2)2 + 2LiH + K-modified LixTiyOz system hint to the fact that the presence of in situ formed nanostructure K2TiO3 is the main responsible for the observed improved kinetic behaviour. %0 journal article %@ 2095-4956 %A Bergemann, N.,Pistidda, C.,Uptmoor, M.,Milanese, C.,Santoru, A.,Emmler, T.,Puszkiel, J.,Dornheim, M.,Klassen, T. %D 2019 %J Journal of Energy Chemistry %N %P 240-254 %R doi:10.1016/j.jechem.2019.03.011 %T A new mutually destabilized reactive hydride system: LiBH4–Mg2NiH4 %U https://doi.org/10.1016/j.jechem.2019.03.011 %X In this work, the hydrogen sorption properties of the LiBH4–Mg2NiH4 composite system with the molar ratio 2:2.5 were thoroughly investigated as a function of the applied temperature and hydrogen pressure. To the best of our knowledge, it has been possible to prove experimentally the mutual destabilization between LiBH4 and Mg2NiH4. A detailed account of the kinetic and thermodynamic features of the dehydrogenation process is reported here. %0 journal article %@ 1463-9076 %A Grasso, M.,Puszkiel, J.,Fernandez Albanesi, L.,Dornheim, M.,Pistidda, C.,Gennari, F. %D 2019 %J Physical Chemistry Chemical Physics %N 36 %P 19825-19834 %R doi:10.1039/c9cp03826d %T CO2 reutilization for methane production via a catalytic process promoted by hydrides %U https://doi.org/10.1039/c9cp03826d 36 %X CO2 emissions have been continuously increasing during the last half of the century with a relevant impact on the planet and are the main contributor to the greenhouse effect and global warming. The development of new technologies to mitigate these emissions poses a challenge. Herein, the recycling of CO2 to produce CH4 selectively by using Mg2FeH6 and Mg2NiH4 complex hydrides as dual conversion promoters and hydrogen sources has been demonstrated. Magnesium-based metal hydrides containing Fe and Ni catalyzed the hydrogenation of CO2 and their total conversion was obtained at 400 °C after 5 h and 10 h, respectively. The complete hydrogenation of CO2 depended on the complex hydride, H2 : CO2 mol ratio, and experimental conditions: temperature and time. For both hydrides, the activation of CO2 on the metal surface and its subsequent capture resulted in the formation of MgO. Investigations on the Mg2FeH6–CO2 system indicated that the main process occurs via the reversed water–gas shift reaction (WGSR), followed by the methanation of CO in the presence of steam. In contrast, the reduction of CO2 by the Mg-based hydride in the Mg2NiH4–CO2 system has a strong contribution to the global process. Complex metal hydrides are promising dual promoter-hydrogen sources for CO2 recycling and conversion into valuable fuels such as CH4. %0 journal article %@ 2075-4701 %A Le, T.,Pistidda, C.,Puszkiel, J.,Milanese, C.,Garroni, S.,Emmler, T.,Capurso, G.,Gizer, G.,Klassen, T.,Dornheim, M. %D 2019 %J Metals %N 10 %P 1061 %R doi:10.3390/met9101061 %T Efficient Synthesis of Alkali Borohydrides from Mechanochemical Reduction of Borates Using Magnesium–Aluminum-Based Waste %U https://doi.org/10.3390/met9101061 10 %X Lithium borohydride (LiBH4) and sodium borohydride (NaBH4) were synthesized via mechanical milling of LiBO2, and NaBO2 with Mg–Al-based waste under controlled gaseous atmosphere conditions. Following this approach, the results herein presented indicate that LiBH4 and NaBH4 can be formed with a high conversion yield starting from the anhydrous borates under 70 bar H2. Interestingly, NaBH4 can also be obtained with a high conversion yield by milling NaBO2·4H2O and Mg–Al-based waste under an argon atmosphere. Under optimized molar ratios of the starting materials and milling parameters, NaBH4 and LiBH4 were obtained with conversion ratios higher than 99.5%. Based on the collected experimental results, the influence of the milling energy and the correlation with the final yields were also discussed. %0 journal article %@ 1996-1073 %A Gizer, G.,Cao, H.,Puszkiel, J.,Pistidda, C.,Santoru, A.,Zhang, W.,He, T.,Chen, P.,Klassen, T.,Dornheim, M. %D 2019 %J Energies %N 14 %P 2779 %R doi:10.3390/en12142779 %T Enhancement Effect of Bimetallic Amide K2Mn(NH2)4 and In-Situ Formed KH and Mn4N on the Dehydrogenation/Hydrogenation Properties of Li–Mg–N–H System %U https://doi.org/10.3390/en12142779 14 %X In this work, we investigated the influence of the K2Mn(NH2)4 additive on the hydrogen sorption properties of the Mg(NH2)2 + 2LiH (Li–Mg–N–H) system. The addition of 5 mol% of K2Mn(NH2)4 to the Li–Mg–N–H system leads to a decrease of the dehydrogenation peak temperature from 200 °C to 172 °C compared to the pristine sample. This sample exhibits a constant hydrogen storage capacity of 4.2 wt.% over 25 dehydrogenation/rehydrogenation cycles. Besides that, the in-situ synchrotron powder X-ray diffraction analysis performed on the as prepared Mg(NH2)2 + 2LiH containing K2Mn(NH2)4 indicates the presence of Mn4N. However, no crystalline K-containing phases were detected. Upon dehydrogenation, the formation of KH is observed. The presence of KH and Mn4N positively influences the hydrogen sorption properties of this system, especially at the later stage of rehydrogenation. Under the applied conditions, hydrogenation of the last 1 wt.% takes place in only 2 min. This feature is preserved in the following three cycles. %0 journal article %@ 0360-3199 %A Gizer, G.,Puszkiel, J.,Cao, H.,Pistidda, C.,Le, T.,Dornheim, M.,Klassen, T. %D 2019 %J International Journal of Hydrogen Energy %N 23 %P 11920-11929 %R doi:10.1016/j.ijhydene.2019.03.133 %T Tuning the reaction mechanism and hydrogenation/dehydrogenation properties of 6Mg(NH2)2single bond9LiH system by adding LiBH4 %U https://doi.org/10.1016/j.ijhydene.2019.03.133 23 %X The hydrogen storage properties of 6Mg(NH2)2single bond9LiH-x(LiBH4) (x = 0, 0.5, 1, 2) system and the role of LiBH4 on the kinetic behaviour and the dehydrogenation/hydrogenation reaction mechanism were herein systematically investigated. Among the studied compositions, 6Mg(NH2)2single bond9LiHsingle bond2LiBH4 showed the best hydrogen storage properties. The presence of 2 mol of LiBH4 improved the thermal behaviour of the 6Mg(NH2)2single bond9LiH by lowering the dehydrogenation peak temperature nearly 25 °C and by reducing the apparent dehydrogenation activation energy of about 40 kJ/mol. Furthermore, this material exhibited fast dehydrogenation (10 min) and hydrogenation kinetics (3 min) and excellent cycling stability with a reversible hydrogen capacity of 3.5 wt % at isothermal 180 °C. Investigations on the reaction pathway indicated that the observed superior kinetic behaviour likely related to the formation of Li4(BH4)(NH2)3. Studies on the rate-limiting steps hinted that the sluggish kinetic behaviour of the 6Mg(NH2)2single bond9LiH pristine material are attributed to an interface-controlled mechanism. On the contrary, LiBH4-containing samples show a diffusion-controlled mechanism. During the first dehydrogenation reaction, the possible formation of Li4(BH4)(NH2)3 accelerates the reaction rates at the interface. Upon hydrogenation, this ‘liquid like’ of Li4(BH4)(NH2)3 phase assists the diffusion of small ions into the interfaces of the amide-hydride matrix. %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 %P 7780 %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 Metal hydrides are known as a potential efficient, low-risk option for high-density hydrogen storage since the late 1970s. In this paper, the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s, interstitial metal hydrides are known as base materials for Ni – metal hydride rechargeable batteries. For hydrogen storage, metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units, i. e. for stationary applications.,With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004, the use of metal hydrides for hydrogen storage in mobile applications has been established, with new application fields coming into focus.,In the last decades, a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more, partly less extensively characterized.,In addition, based on the thermodynamic properties of metal hydrides, this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover, storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles.,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 %@ 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 %@ 1932-7447 %A Le, T.,Pistidda, C.,Puszkiel, J.,Castro Riglos, M.,Karimi, F.,Skibsted, J.,Payandeh GharibDoust, S.,Richter, B.,Emmler, T.,Milanese, C.,Santoru, A.,Hoell, A.,Krumrey, M.,Gericke, E.,Akiba, E.,Jensen, T.,Klassen, T.,Dornheim, M. %D 2018 %J The Journal of Physical Chemistry C %N 14 %P 7642-7655 %R doi:10.1021/acs.jpcc.8b01850 %T Design of a Nanometric AlTi Additive for MgB2-Based Reactive Hydride Composites with Superior Kinetic Properties %U https://doi.org/10.1021/acs.jpcc.8b01850 14 %X Solid-state hydride compounds are a promising option for efficient and safe hydrogen-storage systems. Lithium reactive hydride composite system 2LiBH4 + MgH2/2LiH + MgB2 (Li-RHC) has been widely investigated owing to its high theoretical hydrogen-storage capacity and low calculated reaction enthalpy (11.5 wt % H2 and 45.9 kJ/mol H2). In this paper, a thorough investigation into the effect of the formation of nano-TiAl alloys on the hydrogen-storage properties of Li-RHC is presented. The additive 3TiCl3·AlCl3 is used as the nanoparticle precursor. For the investigated temperatures and hydrogen pressures, the addition of ∼5 wt % 3TiCl3·AlCl3 leads to hydrogenation/dehydrogenation times of only 30 min and a reversible hydrogen-storage capacity of 9.5 wt %. The material containing 3TiCl3·AlCl3 possesses superior hydrogen-storage properties in terms of rates and a stable hydrogen capacity during several hydrogenation/dehydrogenation cycles. These enhancements are attributed to an in situ nanostructure and a hexagonal AlTi3 phase observed by high-resolution transmission electron microscopy. This phase acts in a 2-fold manner, first promoting the nucleation of MgB2 upon dehydrogenation and second suppressing the formation of Li2B12H12 upon hydrogenation/dehydrogenation cycling. %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 %@ 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 %@ 2050-7488 %A Puszkiel, J.A.,Castro Riglos, M.V.,Ramallo-Lopez, J.M.,Mizrahi, M.,Karimi, F.,Santoru, A.,Hoell, A.,Gennari, F.C.,Arneodo Larochette, P.,Pistidda, C.,Klassen, T.,Bellosta von Colbe J.M.,Dornheim, M. %D 2017 %J Journal of Materials Chemistry A %N 25 %P 12922-12933 %R doi:10.1039/c7ta03117c %T A novel catalytic route for hydrogenation–dehydrogenation of 2LiH + MgB2via in situ formed core–shell LixTiO2 nanoparticles %U https://doi.org/10.1039/c7ta03117c 25 %X Aiming to improve the hydrogen storage properties of 2LiH + MgB2 (Li-RHC), the effect of TiO2 addition to Li-RHC is investigated. The presence of TiO2 leads to the in situ formation of core–shell LixTiO2 nanoparticles during milling and upon heating. These nanoparticles markedly enhance the hydrogen storage properties of Li-RHC. Throughout hydrogenation–dehydrogenation cycling at 400 °C a 1 mol% TiO2 doped Li-RHC material shows sustainable hydrogen capacity of ∼10 wt% and short hydrogenation and dehydrogenation times of just 25 and 50 minutes, respectively. The in situ formed core–shell LixTiO2 nanoparticles confer proper microstructural refinement to the Li-RHC, thus preventing the material's agglomeration upon cycling. An analysis of the kinetic mechanisms shows that the presence of the core–shell LixTiO2 nanoparticles accelerates the one-dimensional interface-controlled mechanism during hydrogenation owing to the high Li+ mobility through the LixTiO2 lattice. Upon dehydrogenation, the in situ formed core–shell LixTiO2 nanoparticles do not modify the dehydrogenation thermodynamic properties of the Li-RHC itself. A new approach by the combination of two kinetic models evidences that the activation energy of both MgH2 decomposition and MgB2 formation is reduced. These improvements are due to a novel catalytic mechanism via Li+ source/sink reversible reactions. %0 journal article %@ 2304-6740 %A Puszkiel, J.,Garroni, S.,Milanese, C.,Gennari, F.,Klassen, T.,Dornheim, M.,Pistidda, C. %D 2017 %J Inorganics %N 4 %P 74 %R doi:10.3390/inorganics5040074 %T Tetrahydroborates: Development and Potential as Hydrogen Storage Medium %U https://doi.org/10.3390/inorganics5040074 4 %X The use of fossil fuels as an energy supply becomes increasingly problematic from the point of view of both environmental emissions and energy sustainability. As an alternative, hydrogen is widely regarded as a key element for a potential energy solution. However, different from fossil fuels such as oil, gas, and coal, the production of hydrogen requires energy. Alternative and intermittent renewable sources such as solar power, wind power, etc., present multiple advantages for the production of hydrogen. On one hand, the renewable sources contribute to a remarkable reduction of pollutants released to the air. On the other hand, they significantly enhance the sustainability of energy supply. In addition, the storage of energy in form of hydrogen has a huge potential to balance an effective and synergetic utilization of the renewable energy sources. In this regard, hydrogen storage technology presents a key roadblock towards the practical application of hydrogen as “energy carrier”. Among the methods available to store hydrogen, solid-state storage is the most attractive alternative both from the safety and the volumetric energy density points of view. Because of their appealing hydrogen content, complex hydrides and complex hydride-based systems have attracted considerable attention as potential energy vectors for mobile and stationary applications. In this review, the progresses made over the last century on the development in the synthesis and research on the decomposition reactions of homoleptic tetrahydroborates is summarized. Furthermore, theoretical and experimental investigations on the thermodynamic and kinetic tuning of tetrahydroborates for hydrogen storage purposes are herein reviewed. %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 %@ 0360-3199 %A Paskevicius, M.,Filsoe, U.,Karimi, F.,Puszkiel, J.,Pranzas, P.K.,Pistidda, C.,Hoell, A.,Welter, E.,Schreyer, A.,Klassen, T.,Dornheim, M.,Jensen, T.R. %D 2016 %J International Journal of Hydrogen Energy %N 7 %P 4159-4167 %R doi:10.1016/j.ijhydene.2015.12.185 %T Cyclic stability and structure of nanoconfined Ti-doped NaAlH4 %U https://doi.org/10.1016/j.ijhydene.2015.12.185 7 %X NaAlH4 was melt infiltrated within a CO2 activated carbon aerogel, which had been preloaded with TiCl3. Nanoconfinement was verified by Small Angle X-Ray Scattering (SAXS) and the nature of the Ti was investigated with Anomalous SAXS (ASAXS) and X-Ray Absorption Near Edge Structure (XANES) to determine its size and chemical state. The Ti is found to be in a similar state to that found in the bulk Ti-doped NaAlH4 system where it exists as Al1−xTix nanoalloys. Crystalline phases exist within the carbon aerogel pores, which are analysed by in-situ Powder X-Ray Diffraction (PXD) during hydrogen cycling. The in-situ data reveals that the hydrogen release from NaAlH4 and its hydrogen uptake occurs through the Na3AlH6 intermediate when confined at this size scale. The hydrogen capacity from the nanoconfined NaAlH4 is found to initially be much higher in this CO2 activated aerogel compared with previous studies into unactivated aerogels. %0 journal article %@ 1359-7345 %A Santoru, A.,Pistidda, C.,Soerby, M.H.,Chierotti, M.R.,Garroni, S.,Pinatel, E.,Karimi, F.,Cao, H.,Bergemann, N.,Le, T.T.,Puszkiel, J.,Gobetto, R.,Baricco, M.,Hauback, B.C.,Klassen, T.,Dornheim, M. %D 2016 %J Chemical Communications : ChemComm %N 79 %P 11760-11763 %R doi:10.1039/c6cc05777b %T KNH2–KH: a metal amide–hydride solid solution %U https://doi.org/10.1039/c6cc05777b 79 %X We report for the first time the formation of a metal amide–hydride solid solution. The dissolution of KH into KNH2 leads to an anionic substitution, which decreases the interaction among NH2− ions. The rotational properties of the high temperature polymorphs of KNH2 are thereby retained down to room temperature. %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 %N %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 %@ 0925-8388 %A Busch, N.,Jepsen, J.,Pistidda, C.,Puszkiel, J.A.,Karimi, F.,Milanese, C.,Tolkiehn, M.,Chaudhary, A.-L.,Klassen, T.,Dornheim, M. %D 2015 %J Journal of Alloys and Compounds %N S 1 %P S299-S303 %R doi:10.1016/j.jallcom.2014.12.187 %T Influence of milling parameters on the sorption properties of the LiH-MgB2 system doped with TiCl3 %U https://doi.org/10.1016/j.jallcom.2014.12.187 S 1 %X Hydrogen sorption properties of the LiH–MgB2 system doped with TiCl3 were investigated with respect to milling conditions (milling times, ball to powder (BTP) ratios, rotation velocities and degrees of filling) to form the reactive hydride composite (RHC) LiBH4–MgH2. A heuristic model was applied to approximate the energy transfer from the mill to the powders. These results were linked to experimentally obtained quantities such as crystallite size, specific surface area (SSA) and homogeneity of the samples, using X-ray diffraction (XRD), the Brunauer–Emmett–Teller (BET) method and scanning electron microscopy (SEM), respectively. The results show that at approximately 20 kJ g−1 there are no further benefits to the system with an increase in energy transfer. This optimum energy transfer value indicates that a plateau was reached for MgB2 crystallite size therefore the there was also no improvement of reaction kinetics due to no change in crystallite size. Therefore, this study shows that an optimum energy transfer value was reached for the LiH–MgB2 system doped with TiCl3. %0 journal article %@ 1463-9076 %A Karimi, F.,Pranzas, P.K.,Pistidda, C.,Puszkiel, J.A.,Milanese, C.,Vainio, U.,Paskevicius, M.,Emmler, T.,Santoru, A.,Utke, R.,Tolkiehn, M.,Minella, C.B.,Chaudhary, A.-L.,Boerries, S.,Buckley, C.E.,Enzo, S.,Schreyer, A.,Klassen, T.,Dornheim, M. %D 2015 %J Physical Chemistry Chemical Physics %N 41 %P 27328-27342 %R doi:10.1039/c5cp03557k %T Structural and kinetic investigation of the hydride composite Ca(BH4)2 + MgH2 system doped with NbF5 for solid-state hydrogen storage %U https://doi.org/10.1039/c5cp03557k 41 %X Designing safe, compact and high capacity hydrogen storage systems is the key step towards introducing a pollutant free hydrogen technology into a broad field of applications. Due to the chemical bonds of hydrogen–metal atoms, metal hydrides provide high energy density in safe hydrogen storage media. Reactive hydride composites (RHCs) are a promising class of high capacity solid state hydrogen storage systems. Ca(BH4)2 + MgH2 with a hydrogen content of 8.4 wt% is one of the most promising members of the RHCs. However, its relatively high desorption temperature of ∼350 °C is a major drawback to meeting the requirements for practical application. In this work, by using NbF5 as an additive, the dehydrogenation temperature of this RHC was significantly decreased. To elucidate the role of NbF5 in enhancing the desorption properties of the Ca(BH4)2 + MgH2 (Ca-RHC), a comprehensive investigation was carried out via manometric measurements, mass spectrometry, Differential Scanning Calorimetry (DSC), in situ Synchrotron Radiation-Powder X-ray Diffraction (SR-PXD), X-ray Absorption Spectroscopy (XAS), Anomalous Small-Angle X-ray Scattering (ASAXS), Scanning and Transmission Electron Microscopy (SEM, TEM) and Nuclear Magnetic Resonance (NMR) techniques. %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 %N %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 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 Gosalawit-Utke, R.,Milanese, C.,Javadian, P.,Jepsen, J.,Laipple, D.,Karmi, F.,Puszkiel, J.,Jensen, T.R.,Marini, A.,Klassen, T.,Dornheim, M. %D 2013 %J International Journal of Hydrogen Energy %N 8 %P 3275-3282 %R doi:10.1016/j.ijhydene.2012.12.123 %T Nanoconfined 2LiBH4–MgH2–TiCl3 in carbon aerogel scaffold for reversible hydrogen storage %U https://doi.org/10.1016/j.ijhydene.2012.12.123 8 %X Nanoconfinement of 2LiBH4–MgH2–TiCl3 in resorcinol–formaldehyde carbon aerogel scaffold (RF–CAS) for reversible hydrogen storage applications is proposed. RF–CAS is encapsulated with approximately 1.6 wt. % TiCl3 by solution impregnation technique, and it is further nanoconfined with bulk 2LiBH4–MgH2 via melt infiltration. Faster dehydrogenation kinetics is obtained after TiCl3 impregnation, for example, nanoconfined 2LiBH4–MgH2–TiCl3 requires ∼1 and 4.5 h, respectively, to release 95% of the total hydrogen content during the 1st and 2nd cycles, while nanoconfined 2LiBH4–MgH2 (∼2.5 and 7 h, respectively) and bulk material (∼23 and 22 h, respectively) take considerably longer. Moreover, 95–98.6% of the theoretical H2 storage capacity (3.6–3.75 wt. % H2) is reproduced after four hydrogen release and uptake cycles of the nanoconfined 2LiBH4–MgH2–TiCl3. The reversibility of this hydrogen storage material is confirmed by the formation of LiBH4 and MgH2 after rehydrogenation using FTIR and SR-PXD techniques, respectively.