Iodide substitution in lithium borohydride, LiBH4-LiI

JOURNAL OF ALLOYS AND COMPOUNDS

卷:509

Article

Rude, Line H.^1,2  Groppo, Elena^3,4  Arnbjerg, Lene M.^1,2  Ravnsbaek, Dorthe B.^1,2  Malmkjaer, Regitze A.^1,2  Filinchuk, Yaroslav^1,2,5,6  Baricco, Marcello^3,4  Besenbacher, Flemming^7,8  Jensen, Torben R.^1,2 

[1] Aarhus Univ, Ctr Mat Crystallog, Interdisciplinary Nanosci Ctr, DK-8000 Aarhus C, Denmark

[2] Aarhus Univ, Dept Chem, DK-8000 Aarhus C, Denmark

[3] Univ Turin, Dipartimento Chim IFM, Turin, Italy

[4] Univ Turin, NIS, Turin, Italy

[5] Swiss Norwegian Beam Lines ESRF, F-38043 Grenoble, France

[6] Catholic Univ Louvain, Inst Condensed Matter & Nanosci, B-1348 Louvain, Belgium

[7] Aarhus Univ, Interdisciplinary Nanosci Ctr iNANO, DK-8000 Aarhus C, Denmark

[8] Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark

关键词: Hydrogen storage;    Lithium borohydride;    Anion substitution;    In situ powder X-ray diffraction;    Sieverts method;    Infrared spectroscopy;   

DOI  :  10.1016/j.jallcom.2011.05.031

来源: Elsevier

【 摘 要 】

The new concept, anion substitution, is explored for possible improvement of hydrogen storage properties in the system LiBH4-LiI. The structural chemistry and the substitution mechanism are analyzed using Rietveld refinement of in situ synchrotron radiation powder X-ray diffraction (SR-PXD) data, attenuated total reflectance infrared spectroscopy (ATR-IR), differential scanning calorimetry (DSC) and Sieverts measurements. Anion substitution is observed as formation of two solid solutions of Li(BH4)(1-x)I-x, which merge into one upon heating. The solid solutions have hexagonal structures (space group P6(3)mc) similar to the structures of h-LiBH4 and beta-LiI. The solid solutions have iodide contents in the range similar to 0-62 mol% and are stable from below room temperature to the melting point at 330 degrees C. Thus the stability of the solid solutions is higher as compared to that of the orthorhombic and hexagonal polymorphs of LiBH4 and alpha- and beta-LiI. Furthermore, the rehydrogenation properties of the iodide substituted solid solution Li(BH4)(1-x)I-x, measured by the Sieverts method, are improved as compared to those of LiBH4. After four cycles of hydrogen release and uptake the Li(BH4)(1-x)I-x solid solution maintains 68% of the calculated hydrogen storage capacity in contrast to LiBH4, which maintains only 25% of the storage capacity after two cycles under identical conditions. (C) 2011 Elsevier B. V. All rights reserved.

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