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Stability and Reversibility of Lithium Borohydrides Doped by Metal Halides and Hydrides

Au, Ming and Jurgensen, Arthur R. and Spencer, William A. and Anton, Donald L. and Pinkerton, Frederick E. and Hwang, Son-Jong and Kim, Chul and Bowman, Robert C., Jr. (2008) Stability and Reversibility of Lithium Borohydrides Doped by Metal Halides and Hydrides. Journal of Physical Chemistry C, 112 (47). pp. 18661-18671. ISSN 1932-7447. https://resolver.caltech.edu/CaltechAUTHORS:AUMjpcc08

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Abstract

In an effort to develop reversible metal borohydrides with high hydrogen storage capacities and low dehydriding temperature, doping LiBH4 with various metal halides and hydrides has been conducted. Several metal halides such as TiCl3, TiF3, and ZnF2 effectively reduced the dehydriding temperature through a cation exchange interaction. Some of the halide doped LiBH4 are partially reversible. The LiBH4 + 0.1TiF3 desorbed 3.5 wt % and 8.5 wt % hydrogen at 150 and 450 °C, respectively, with subsequent reabsorption of 6 wt % hydrogen at 500 °C and 70 bar observed. XRD and NMR analysis of the rehydrided samples confirmed the reformation of LiBH4. The existence of the (B12H12)−2 species in dehydrided and rehydrided samples gives insight into the resultant partial reversibility. A number of other halides, MgF2, MgCl2, CaCl2, SrCl2, and FeCl3, did not reduce the dehydriding temperature of LiBH4 significantly. XRD and TGA-RGA analyses indicated that an increasing proportion of halides such as TiCl3, TiF3, and ZnCl2 from 0.1 to 0.5 mol makes lithium borohydrides less stable and volatile. Although the less stable borohydrides such as LiBH4 + 0.5TiCl3, LiBH4 + 0.5TiF3, and LiBH4 + 0.5ZnCl2 release hydrogen at room temperature, they are not reversible due to unrecoverable boron loss caused by diborane emission. In most cases, doping that produced less stable borohydrides also reduced the reversible hydrogen uptake. It was also observed that halide doping changed the melting points and reduced air sensitivity of lithium borohydrides.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp8024304DOIArticle
ORCID:
AuthorORCID
Hwang, Son-Jong0000-0002-3210-466X
Bowman, Robert C., Jr.0000-0002-2114-1713
Additional Information:© 2008 American Chemical Society. Received: March 19, 2008; Revised Manuscript Received: September 23, 2008. Publication Date (Web): October 30, 2008. This project is financially supported by General Motors Corporation. The authors also thank Dr. Scott Jorgensen for constructive discussions and suggestions on the research. Savannah River National Laboratory is operated by Savannah River Nuclear Solution for the U.S. Department of Energy under contract DE-AC09-08SR22470. This research was partially performed at the Jet Propulsion Laboratory, which is operated by the California Institute of Technology under contract with the NASA. This work was also partially supported by DOE through Award Number DE-AI-01-05EE11105. The NMR facility at Caltech was supported by the National Science Foundation (NSF) under Grant Number 9724240 and partially supported by the MRSEC Program of the NSF under Award Number DMR-0520565.
Funders:
Funding AgencyGrant Number
General MotorsUNSPECIFIED
Department of Energy (DOE)DE-AC09-08SR22470
Department of Energy (DOE)DE-AI-01-05EE11105
NSFDMR-9724240
NSFDMR-0520565
Issue or Number:47
Record Number:CaltechAUTHORS:AUMjpcc08
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:AUMjpcc08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12760
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:22 Dec 2008 23:05
Last Modified:03 Oct 2019 00:31

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