Published August 16, 2013 | Version Final version
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Sorption behavior of the MgH2-Mg2FeH6 hydride storage system synthesized by mechanical milling followed by sintering

Creators

  • 1. Consejo Nacional de Investigaciones Cientı´ficas y Tecnicas, CONICET-Centro Atomico Bariloche (CNEA), R8402AGP, S. C. de Bariloche, Rı´o Negro, Argentina
  • 2. Institute of Materials Research, Helmholtz-Zentrum Geesthacht, 21502 Geesthacht, Germany
  • 3. School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
  • 4. Center for Energy Materials, iNANO and Department of Chemistry, University of Aarhus, Aarhus C8000, Denmark
  • 5. MAX-lab, Lund University, Lund S-22100, Sweden
  • 6. Institute of Materials Research, Materials Technology, Helmholtz-Zentrum Geesthacht GmbH, Max-Planck-Strasse 1, D-21502 Geesthacht, Schleswig-Holstein, Germany

Description

The hydrogen sorption behavior of the Mg2FeH6eMgH2 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 Mg2FeH6eMgH2 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 ºC. 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.

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