Probing the structure, stability and hydrogen storage properties of calcium dodecahydro-closo-dodecaborate
Abstract
Calcium borohydride can reversibly store up to 9.6 wt% hydrogen; however, the material displays poor cyclability, generally associated with the formation of stable intermediate species. In an effort to understand the role of such intermediates on the hydrogen storage properties of Ca(BH_4)_2, calcium dodecahydro-closo-dodecaborate was isolated and characterized by diffraction and spectroscopic techniques. The crystal structure of CaB_(12)H_(12) was determined from powder XRD data and confirmed by DFT and neutron vibrational spectroscopy studies. Attempts to dehydrogenate/hydrogenate mixtures of CaB_(12)H_(12) and CaH_2 were made under conditions known to favor partial reversibility in calcium borohydride. However, up to 670 K no notable formation of Ca(BH_4)_2 (during hydrogenation) or CaB_6 (during dehydrogenation) occurred. It was demonstrated that the stability of CaB_(12)H_(12) can be significantly altered using CaH_2 as a destabilizing agent to favor the hydrogen release.
Additional Information
© 2010 Elsevier. Received 27 October 2009; revised 16 March 2010; accepted 16 March 2010; available online 20 March 2010. The authors would like to acknowledge the many valuable suggestions made by Drs. Ewa Rönnebro, Eric Majzoub, Timothy Boyle and Leonard Klebanoff. We are grateful to Dr. Satish S. Jalisatgi for generously providing the Li2B12H12 and K2B12H12 samples and to Jeff Chames for help with the SEM/EDX experiments. We gratefully acknowledge financial support from the US Department of Energy, Office of Energy Efficiency and Renewable Energy, in the Hydrogen, Fuel Cells & Infrastructure Technologies Program under Contract nos. DE-AC04-94AL85000, DE-AI-01-05EE11104, and DE-AI-01-05EE11105. The NMR facility at Caltech was supported by the National Science Foundation (NSF) under Grant no. 9724240 and partially supported by the MRSEC Program of the NSF under Award Number DMR-0520565.Attached Files
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Additional details
- Eprint ID
- 18620
- Resolver ID
- CaltechAUTHORS:20100609-113343689
- DE-AC04-94AL85000
- Department of Energy (DOE)
- DE-AI-01-05EE11104
- Department of Energy (DOE)
- DE-AI-01-05EE11105
- Department of Energy (DOE)
- DMR-9724240
- NSF
- DMR-0520565
- NSF
- Created
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2010-06-09Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field