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A candidate LiBH4 for hydrogen storage: Crystal structures and reaction mechanisms of intermediate phases

Kang, Jeung Ku and Kim, Se Yun and Han, Young Soo and Muller, Richard P. and Goddard, William A., III (2005) A candidate LiBH4 for hydrogen storage: Crystal structures and reaction mechanisms of intermediate phases. Applied Physics Letters, 87 (11). Art. No. 111904. ISSN 0003-6951. http://resolver.caltech.edu/CaltechAUTHORS:KANapl05

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Abstract

First-principles calculation and x-ray diffraction simulation methods have been used to explore crystal structures and reaction mechanisms of the intermediate phases involved in dehydriding of LiBH4. LiBH4 was found to dehydride via two sequential steps: first dehydriding through LiBH, followed by the dehydriding of LiBH through LiB. The first step, which releases 13.1 wt. % hydrogen, was calculated to have an activation barrier of 2.33 eV per formula unit and was endothermic by 1.28 eV per formula unit, while the second step was endothermic by 0.23 eV per formula unit. On the other hand, if LiBH4 and LiBH each donated one electron, possibly to the catalyst doped on their surfaces, it was found that the barrier for the first step was reduced to 1.50 eV. This implies that the development of the catalyst to induce charge migration from the bulk to the surface is essential to make LiBH4 usable as a hydrogen storage material in a moderate temperature range, which is also important to stabilize the low-temperature structure of Pnma (no. 62) LiBH on dehydrogenation. Consequently, the high 13.1 wt. % hydrogen available from the dehydriding of LiBH4 and LiBH and their phase stability on Pnma when specific catalysts were used suggest that LiBH4 has good potential to be developed as the hydrogen storage medium capable of releasing the Department of Energy target of 6.5 wt. % for a hydrogen fuel cell car in a moderate temperature range.


Item Type:Article
Additional Information:©2005 American Institute of Physics. Received 17 December 2004; accepted 4 August 2005; published online 6 September 2005. This research was supported by General Motors Global Alternative Proposal Center.
Subject Keywords:lithium compounds; hydrogen storage; crystal structure; X-ray diffraction; ab initio calculations; catalysts; hydrogenation
Record Number:CaltechAUTHORS:KANapl05
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:KANapl05
Alternative URL:http://dx.doi.org/10.1063/1.2042632
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3464
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Jun 2006
Last Modified:26 Dec 2012 08:54

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