Mechanical and Thermal Dehydrogenation of the Mechano-Chemically Synthesized Calcium Alanate (Ca(AlH4)2) and Lithium Chloride (LiCl) Composite

Materials

Robert A. Varin²  Ewelina E. Koᖼiuczyk¹  Tomasz Czujko¹ 

[1] Department of Advanced Materials and Technologies, Military University of Technology, PL-00-908 Warsaw, ul. S. Kaliskiego 2, Poland; E-Mails:;Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave., Waterloo, ON N2L 3G1, Canada

关键词: hydrogen generation;    mechano-chemical synthesis;    (Ca(AlH₄)₂+2LiCl) composite;    mechanical and thermal dehydrogenation;   

DOI  :  10.3390/ma8063479

来源: mdpi

【 摘 要 】

LiAlH₄ and CaCl₂ were employed for mechano-chemical activation synthesis (MCAS) of Ca(AlH₄)₂ and LiCl hydride composite. After short ball milling time, their X-ray diffraction (XRD) peaks are clearly observed. After ball milling for a longer duration than 0.5 h, the CaAlH₅ diffraction peaks are observed which indicates that Ca(AlH₄)₂ starts decomposing during ball milling into CaAlH₅+Al+1.5H₂. It is estimated that less than 1 wt % H₂ was mechanically dehydrogenated in association with decomposition reaction. After 2.5 h of ball milling, no Ca(AlH₄)₂ diffraction peaks were observed on XRD patterns which suggests that Ca(AlH₄)₂ was decomposed. Thermal behavior of ball milled powders, which was investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), indicates that a certain fraction of Ca(AlH₄)₂ could have been disordered/amorphized during ball milling being undetectable by XRD. The apparent activation energy for the decomposition of Ca(AlH₄)₂ and CaAlH₅ equals 135 kJ/mol and 183 kJ/mol, respectively.

【 授权许可】

CC BY   
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