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The composite 2LiBH4 : MgH2 has recently received attention as a potential hydrogen storage material. This is mainly due to its high storage capacity. However, the temperatures needed to obtain adequate reaction kinetics are still too high for practical applications. In the present work we study the effect of Ni and carbon nanotube addition as catalysers. We found that different synthesis methods of the composite lead to different hydrogen absorption/desorption kinetic behaviours. These changes can be attributed to morphological and microstructural differences caused by the dissimilar milling stages at which the nanotubes were introduced during the sample synthesis. An induction time during the hydrogen desorption appeared as a consequence of the different dispersions of the carbon nanotubes observed in the samples prepared with both synthesis methods. It was also found that equilibrium pressure increased when the temperature decreased below 375 °C, this effect was kinetic and it was possible to conclude that the addition of nanotubes had no effect on the thermodynamics of the system. Fil: Cova, Federico Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Gennari, Fabiana Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Arneodo Larochette, Pierre Paul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina

The safest way to store hydrogen is in solid form, physically entrapped in molecular form in highly porous materials, or chemically bound in atomic form in hydrides. Among the different families of these compounds, alkaline and alkaline earth metals alumino-hydrides (alanates) have been regarded as promising storing media and have been extensively studied since 1997, when Bogdanovic and Schwickardi reported that Ti-doped sodium alanate could be reversibly dehydrogenated under moderate conditions. In this review, the preparative methods; the crystal structure; the physico-chemical and hydrogen absorption-desorption properties of the alanates of Li, Na, K, Ca, Mg, Y, Eu, and Sr; and of some of the most interesting multi-cation alanates will be summarized and discussed. The most promising alanate-based reactive hydride composite (RHC) systems developed in the last few years will also be described and commented on concerning their hydrogen absorption and desorption performance. Fil: Milanese, Chiara. Universita Degli Studi Di Pavia; Italia Fil: Garroni, Sebastiano. Universidad de Burgos; España Fil: Gennari, Fabiana Cristina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Marini, Amedeo. Universita Degli Studi Di Pavia; Italia Fil: Klassen, Thomas. Helmholtz-zentrum Geesthacht; Alemania Fil: Dornheim, Martin. Helmholtz-zentrum Geesthacht; Alemania Fil: Pistidda, Claudio. Helmholtz-zentrum Geesthacht; Alemania

The LithiumeBoron Reactive Hydride Composite System (Li-RHC) (2 LiH þ MgB2/2 LiBH4- þ MgH2) is a high-temperature hydrogen storage material suitable for energy storage appli- cations. Herein, a comprehensive gas-solid kinetic model for hydrogenation is developed. Based on thermodynamic measurements under absorption conditions, the system's enthalpy DH and entropy DS are determined to amount to —34 ± 2 kJ∙mol H—2 1 and —70 ± 3 J∙K—1∙mol H—2 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 H—2 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 opti- mized hydrogen/energy storage vessels via finite element method (FEM) simulations., The authors would like to thankfully acknowledge the Karl- Vossloh-Stiftung for the financial support provided for this project (Project Number S047/10043/2017). Also, the authors acknowledge Kristin Przybilla for the experimental work related to the PCI assessment and for previous experiments, which have led to the current developments. Lastly, we thank Oliver Metz for all the technical support. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and the Government of Catalonia's Agency for Business Competitiveness(ACCIÓ).