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Probing the unusual anion mobility of LiBH_4 confined in highly ordered nanoporous carbon frameworks via solid state NMR and quasielastic neutron scattering

Liu, Xiangfeng and Majzoub, Eric H. and Stavila, Vitalie and Bhakta, Raghunandan K. and Allendorf, Mark D. and Shane, David T. and Conradi, Mark S. and Verdal, Nina and Udovic, Terrence J. and Hwang, Son-Jong (2013) Probing the unusual anion mobility of LiBH_4 confined in highly ordered nanoporous carbon frameworks via solid state NMR and quasielastic neutron scattering. Journal of Materials Chemistry A, 1 (34). pp. 9935-9941. ISSN 2050-7488. https://resolver.caltech.edu/CaltechAUTHORS:20130917-092612218

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Abstract

Particle size and particle–framework interactions have profound effects on the kinetics, reaction pathways, and even thermodynamics of complex hydrides incorporated in frameworks possessing nanoscale features. Tuning these properties may hold the key to the utilization of complex hydrides in practical applications for hydrogen storage. Using carefully synthesized, highly-ordered, nanoporous carbons (NPCs), we have previously shown quantitative differences in the kinetics and reaction pathways of LiBH_4 when incorporated into the frameworks. In this paper, we probe the anion mobility of LiBH_4 confined in NPC frameworks by a combination of solid state NMR and quasielastic neutron scattering (QENS) and present some new insights into the nanoconfinement effect. NMR and QENS spectra of LiBH_4 confined in a 4 nm pore NPC suggest that the BH_4− anions nearer the LiBH_4–carbon pore interface exhibit much more rapid translational and reorientational motions compared to those in the LiBH_4 interior. Moreover, an overly broadened BH_4− torsional vibration band reveals a disorder-induced array of BH_4− rotational potentials. XRD results are consistent with a lack of LiBH_4 long-range order in the pores. Consistent with differential scanning calorimetry measurements, neither NMR nor QENS detects a clear solid–solid phase transition as observed in the bulk, indicating that borohydride–framework interactions and/or nanosize effects have large roles in confined LiBH_4.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1039/c3ta12051a DOIArticle
http://pubs.rsc.org/en/Content/ArticleLanding/2013/TA/c3ta12051aPublisherArticle
ORCID:
AuthorORCID
Stavila, Vitalie0000-0003-0981-0432
Hwang, Son-Jong0000-0002-3210-466X
Additional Information:© 2013 The Royal Society of Chemistry. Received 25 May 2013, Accepted 02 Jul 2013; First published online 02 Jul 2013. This work was funded by the U.S. Department of Energy in the Hydrogen, Fuel Cells, and Infrastructure Technologies Program through the office Energy Efficiency and Renewable Energy. This work utilized facilities supported in part by the National Science Foundation under Agreement DMR-0944772. This work was partially supported by DOE-EERE under Agreement no. DEEE0002978. The work at Washington University was supported by DOE Basic Energy Sciences grant DE-FG02-05ER46256. 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-520565. The work at University of Chinese Academy of Sciences was supported by “Hundred Talents Project” and the National Basic Research Program of China (973 Program, 2010CB833101).
Funders:
Funding AgencyGrant Number
NSFDMR-0944772
Department of Energy (DOE)DE-EE0002978
Department of Energy (DOE)DE-FG02-05ER46256
NSFDMR-9724240
NSFDMR-520565
National Basic Research Program of China 973 Program2010CB833101
Issue or Number:34
Record Number:CaltechAUTHORS:20130917-092612218
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130917-092612218
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41358
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Sep 2013 19:53
Last Modified:09 Mar 2020 13:19

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