Reversible hydrogen storage in Mg(HxF1-x)2 solid solutions

JOURNAL OF ALLOYS AND COMPOUNDS

卷:708

Article

Pighin, S. A.^1,2  Urretavizcaya, G.^1,3  Castro, F. J.^1,3 

[1] Consejo Nacl Invest Cient & Tecn, CNEA, Ctr Atom Bariloche, San Carlos De Bariloche, Rio Negro, Argentina

[2] Univ Nacl Comahue, Ctr Reg Univ Bariloche, San Carlos De Bariloche, Rio Negro, Argentina

[3] Univ Nacl Cuyo, Inst Balseiro, San Carlos De Bariloche, Rio Negro, Argentina

关键词: Hydrogen storage;    Solid solutions;    Mechanical milling;   

DOI  :  10.1016/j.jallcom.2017.02.297

来源: Elsevier

【 摘 要 】

Mg( HxF1-x)(2) solid solutions have been synthesized by mechanical milling MgF2 and MgH2 under H-2 atmosphere. Complete solubility has been observed at 475 degrees C. The solid solution presents a rutile-type structure with the anion site randomly occupied by H- or F- and with lattice parameters showing positive deviations from Vegard's law. The solution can be decomposed and re-formed reversibly by changing H-2 pressure. For example, Mg( H0.9F0.1)(2) reversibly stores 5.5 wt. % H-2 in less than 3 min at 440 degrees C. During decomposition H2 is released, and Mg and a solution rich in F appear as products. This process takes place in two clearly marked stages controlled by F- concentration in the material. The decomposition enthalpy of the first one is close to that of MgH2 for Mg( H0.9F0.1)(2), and decreases with the H content in the solution. (C) 2017 Elsevier B.V. All rights reserved.

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