Sorption behavior of the MgH_2-Mg_2FeH_6 hydride storage system synthesized by mechanical milling followed by sintering

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作   者：

Julian Puszfeiel;  Fabiana Gennari;  Pierre Arneodo Larochette;  Fahim Karimi;  Claudio Pistidda;  Rapee Gosalawit-Utke;  Julian Jepsen;  Torben R. Jensen;  Carsten Gundlach;  Jose Bellosta von Colbe;  Thomas Klassen;  Martin Dornheim; 

作者机构：

Helmholtz-Zentrum Geesthacht;  Sweden;  Lund S-22100;  School of Chemistry;  Institute of Materials Research;  University of Aarhus;  MAX-lab;  Germany;  Center for Energy Materials;  H;  Geesthacht 21502;  Aarhus C8000;  Lund University;  Argentina;  Materials Technology;  Nakhon Ratchasima 30000;  Suranaree University of Technology;  Thailand;  Instituto Balseiro (UNCuyo and CNEA);  Institute of Science;  S. C. de Bariloche R8402AGP;  Av. Bustillo fern 9.5;  iNANO and Department of Chemistry;  Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) and Centre Atomico Bariloche;  Denmark; 

关键词：

Magnesium hydride;  Reaction path;  Hydride mixture;  Complex hydride;  Desorption kinetics; 

期刊名称：

International journal of hydrogen energy

i s s n：

0360-3199

年卷期：

2013 年 38 卷 34 期

页   码：

14618-14630

页   码：

摘   要：

The hydrogen sorption behavior of the Mg_2FeH_6-MgH_2 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 Mg_2FeH_6-MgH_2 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 MgH_2 is a precursor for Mg_2FeH_6 formation and remained as hydrided phase in the obtained material. Diffusion constraints preclude the further formation of Mg_2FeH_6. Upon dehydriding, our results suggest that MgH_2 and Mg_2FeH_6 decompose independently in a narrow temperature range between 275 and 300 ℃. Moreover, the decomposition behavior of both hydrides in the Mg_2FeH_6-MgH_2 hydride mixture is influenced by each other via dual synergetic-destabilizing effects. The final hydriding/dehydriding products and therefore the kinetic behavior of the Mg_2FeH_6 -MgH_2 hydride system exhibits a strong dependence on the temperature and pressure conditions.