Abstract
A detailed analysis of the dehydrogenation mechanism and reversibility of LiBH4 doped by as-derived Al (denoted Al*) from AlH3 was performed by thermogravimetry (TG), differential scanning calorimetry (DSC), mass spectral analysis (MS), powder X-ray diffraction (XRD), scanning electronic microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results show that the dehydrogenation of LiBH4/Al* is a five-step reaction: (1) LiBH4 + Al → LiH + AlB2 + “Li-Al-B-H” + B2H6 + H2; (2) the decomposition of “Li-Al-B-H” compounds liberating H2; (3) 2LiBH4 + Al → 2LiH + AlB2 + 3H2; (4) LiBH4 → LiH + B + 3/2H2; and (5) LiH + Al → LiAl + 1/2H2. Furthermore, the reversibility of the LiBH4/Al* composite is based on the following reaction: LiH + LiAl + AlB2 + 7/2H2 ↔ 2LiBH4 + 2Al. The extent of the dehydrogenation reaction between LiBH4 and Al* greatly depends on the precipitation and growth of reaction products (LiH, AlB2, and LiAl) on the surface of Al*. A passivation shell formed by these products on the Al* is the kinetic barrier to the dehydrogenation of the LiBH4/Al* composite.
Highlights
Hydrogen is recognized as an ideal energy vector with the advantages of high combustion value and zero pollution [1,2,3]
Lithium borohydride (LiBH4 ) has drawn much attention for on-board hydrogen storage due to its theoretical hydrogen storage capacity as high as 18.5 wt.%, which far exceeds the requirements of vehicle hydrogen storage material by the US department of energy [7,8]
The reversibility of LiBH4 is poor, and rehydrogenation requires a temperature over 600 ◦ C under 350 bar H2 [9,10]
Summary
Hydrogen is recognized as an ideal energy vector with the advantages of high combustion value and zero pollution [1,2,3]. Various methods have been developed to improve the dehydrogenation properties and reversibility of LiBH4. The formation of MgB2 during the dehydrogenation reaction destabilized LiBH4 , and the reversibility of the LiBH4 -MgH2 composite was better than pure LiBH4. Many metal hydrides or complex hydrides have been employed to improve the hydrogen storage properties of LiBH4 [14,15,16,17,18,19,20,21]. 9, 559 hydrides complex hydrides have been employed to improve the hydrogen storage properties of. Limits improvement of dehydrogenation and of thedehydrogenation reversibility of LiBH the utilization. In order to investigate the mechanism and influence of pure Al on the dehydrogenation purereversibility. The hydrogen desorption properties and mechanism of the LiBH4 /Al*.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
