2012年
Ca7Ge-type hydride Mg6VNaxHy (0 <= x <= 1): High pressure synthesis, synchrotron X-ray analysis and hydrogen storage properties
Journal of Power Sources
- ,
- ,
- ,
- ,
- ,
- ,
- ,
- 巻
- 210
- 号
- 開始ページ
- 158
- 終了ページ
- 162
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.jpowsour.2012.03.034
- 出版者・発行元
- ELSEVIER SCIENCE BV
A powder mixture of MgH2:VH2:NaH = 6:1:n is treated under 8 GPa at 873 K using an eight-anvil apparatus in order to investigate the influence of NaH addition to Mg6VHy, a Ca7Ge-type FCC hydride. Synchrotron radiation X-ray diffraction (SR-XRD) of the obtained sample reveals that Na occupies the vacant 4b site in Mg6VHy to form Mg6VNaxHy (0 <= x <= 1) as the main product while retaining its Ca7Ge-type structure. The Rietveld analysis of the SR-XRD data suggests that the bond lengths between hydrogen and magnesium remain constant through the Na addition. All the samples reversibly desorb and absorb hydrogen at 620-630 and 590-600 K, respectively, under 0.5 MPa (H-2). These temperatures are, respectively, about 70 and 120K lower than those of MgH2. The hydrogen capacity of the main product phase, Mg6VNaxHy, is estimated to be 5-6 mass% from the pressure-composition isotherms (PCIs) by taking its content rate in the specimen into account. The reaction enthalpies calculated from the van't Hoff relation of the PC's do not significantly differ from that of MgH2. The bond lengths and energies between hydrogen and magnesium are not affected by the perturbation by the NaH addition in the lattice in Mg6VNaxHy. (C) 2012 Elsevier B.V. All rights reserved.
- リンク情報
- ID情報
-
- DOI : 10.1016/j.jpowsour.2012.03.034
- ISSN : 0378-7753
- ORCIDのPut Code : 44380233
- Web of Science ID : WOS:000305108400025