Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-24T14:01:51.880Z Has data issue: false hasContentIssue false

In-situ Raman study of the thermal decomposition of LiBH4

Published online by Cambridge University Press:  31 January 2011

Daniel Reed
Affiliation:
[email protected]@bham.ac.uk, University of Birmingham, Metallurgy and Materials, Birmingham, United Kingdom
David Book
Affiliation:
[email protected], University of Birmingham, Metallurgy and Materials, Birmingham, United Kingdom
Get access

Abstract

With relatively high gravimetric and volumetric hydrogen storage capacities, borohydrides have attracted interest as potential hydrogen storage media. Lithium borohydride has a maximum theoretical gravimetric hydrogen storage density of 18.4 wt%, and has been shown to be reversible when heated to 600°C in 350 bar hydrogen1. It is hoped that a greater understanding of the decomposition and reformation mechanisms, may lead to the development of LiBH4-based materials that can absorb and desorb hydrogen under less extreme conditions. However, these studies have proved a challenge: currently most in-situ investigations have used x-ray diffraction or neutron diffraction however these cannot readily give information on non-crystalline or liquid phases. The preparation of samples measured ex-situ via XRD, NMR2 and Raman3 have shown the reaction products and stable intermediates during the thermal decomposition, however, it is very difficult to detect short lived intermediate (or byproduct) species. Raman spectroscopy has the advantages that: materials with only short-range order can be analysed; and by focusing the laser on regions in a sample the reaction path can be monitored with changing temperature with a rapid scan rate.

After heating lithium borohydride through its phase change and melting point, shifts in peak position and peak width were observed, which agreed with other studies4. A sample was also heated to 500°C (under 1 bar Ar) to decompose the sample. A number of intermediates and reaction products have been predicted and observed ex situ. This work shows the in situ formation of lithium dodecaborane (Li2B12H12) and amorphous boron from liquid lithium borohydride. It is therefore possible to determine at what temperatures certain intermediates and products form.

Type
Research Article
Copyright
Copyright © Materials Research Society 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

(1) Racu, A. M.; Schoenes, J.; Lodziana, Z.; Borgschulte, A.; Zuttel, A. Journal of Physical Chemistry A 2008, 112, 97169722.Google Scholar
(2) Hagemann, H.; Filinchuk, Y.; Chernyshov, D.; van Beek, W. Phase Transitions 2009, 82, 344355.Google Scholar
(3) Orima, S.; Nakamori, Y.; Kitahara, G.; Miwa, K.; Ohba, N.; Towata, S.; Zuttel, A. Journal Of Alloys And Compounds 2005, 404, 427430.Google Scholar
(4) Vajo, J. J.; Salguero, T. T.; Gross, A. E.; Skeith, S. L.; Olson, G. L. Journal Of Alloys And Compounds 2007, 446, 409414.Google Scholar
(5) Vajo, J. J.; Olson, G. L. Scripta Materialia 2007, 56,829834.Google Scholar
(6) Soulie, J. P.; Renaudin, G.; Cerny, R.; Yvon, K. Journal Of Alloys And Compounds 2002, 346, 200205.Google Scholar
(7) Zuttel, A.; Rentsch, S.; Fischer, P.; Wenger, P.; Sudan, P.; Mauron, P.; Emmenegger, C. Journal Of Alloys And Compounds 2003, 356, 515520.Google Scholar
(8) Ohba, N.; Miwa, K.; Aoki, M.; Noritake, T.; Towata, S.; Nakamori, Y.; Orimo, S.; Zuttel, A. Phys. Rev. B 2006, 74, 075110.Google Scholar
(9) Orimo, S. I.; Nakamori, Y.; Ohba, N.; Miwa, K.; Aoki, M.; Towata, S.; Zuttel, A. kamori, Applied Physics Letters 2006, 89, 021920.Google Scholar
(10) Hwang, S. J.; Bowman, R. C.; Reiter, J. W.; Rijssenbeek, J.; Soloveichik, G. L.; Zhao, J. C.; Kabbour, H.; Ahn, C. C. Journal Of Physical Chemistry 2008, 112 31643169.Google Scholar
(11) Gomes, S.; Hagemann, H.; Yvon, K. Journal Of Alloys And Compounds 2002, 346, 206210.Google Scholar