Boesenberg, U. Kim, J. W. Gosslar, D. Eigen, N. Jensen, T. R. von Colbe, J. M. Bellosta Zhou, Y. Dahms, M. Kim, D. H. Guenther, R. Cho, Y. W. Oh, K. H. Klassen, T. Bormann, R. Dornheim, M. 2024-01-20T19:31:07Z 2024-01-20T19:31:07Z 2021-09-02 2010-05 1359-6454 https://pubs.kist.re.kr/handle/201004/131495 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. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD HYDROGEN STORAGE METAL-HYDRIDES STATE MECHANISMS Role of additives in LiBH4-MgH2 reactive hydride composites for sorption kinetics Article 10.1016/j.actamat.2010.02.012 1 ACTA MATERIALIA, v.58, no.9, pp.3381 - 3389 ACTA MATERIALIA 58 9 3381 3389 scie scopus 000277747400019 2-s2.0-77950078868 Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Materials Science Metallurgy & Metallurgical Engineering Article HYDROGEN STORAGE METAL-HYDRIDES STATE MECHANISMS Hydrogen storage Nanocomposites Heterogeneous nucleation of phase transformations Phase transformation kinetics