The crystal chemistry and hydrogen storage properties of light metal borohydrides

<p>This work examines various light metal borohydrides, particularly those formed from group II metals, with the aim of understanding their fundamental physical properties and improving their hydrogen storage ability. The structure of a new phase (γ) of Mg(BH<sub>4</sub>)<sub>...

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Main Author: Culligan, SD
Other Authors: Edwards, P
Format: Thesis
Language:English
Published: 2013
Subjects:
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author Culligan, SD
author2 Edwards, P
author_facet Edwards, P
Culligan, SD
author_sort Culligan, SD
collection OXFORD
description <p>This work examines various light metal borohydrides, particularly those formed from group II metals, with the aim of understanding their fundamental physical properties and improving their hydrogen storage ability. The structure of a new phase (γ) of Mg(BH<sub>4</sub>)<sub>2</sub> is reported and the decomposition is fully characterized in a combination of diffraction and thermogravimetric studies. The bulk properties of γ-Mg(BH<sub>4</sub>)<sub>2</sub> are compared to those of an SiO<sub>2</sub> isostructure and probed by various neutron scattering techniques. Negative thermal expansion is observed at low temperatures and the material absorbs up to 1.5 moles of hydrogen gas to form one of the most gravimetrically hydrogen-dense materials ever reported. The structural evolution of Ca(BH<sub>4</sub>)<sub>2</sub> under different synthetic conditions and external influences (e.g. temperature) is studied up until the material decomposes. The effects of various additives on group II metal borohydrides are also examined and the influence of each is justified by observing subtle structural changes in the mixed system via <em>in situ</em> synchrotron X-ray powder diffraction and <sup>11</sup>B NMR measurements.</p>
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spelling oxford-uuid:5a27d358-6b0d-4287-8b5d-f18304533dde2024-08-29T11:18:48ZThe crystal chemistry and hydrogen storage properties of light metal borohydridesThesishttp://purl.org/coar/resource_type/c_db06uuid:5a27d358-6b0d-4287-8b5d-f18304533ddeCrystallographyHydrogen StorageSolid state chemistryStructural chemistryInorganic chemistryChemical crystallographyAtomic scale structure and propertiesEnglishOxford University Research Archive - Valet2013Culligan, SDEdwards, PDavid, WIF<p>This work examines various light metal borohydrides, particularly those formed from group II metals, with the aim of understanding their fundamental physical properties and improving their hydrogen storage ability. The structure of a new phase (γ) of Mg(BH<sub>4</sub>)<sub>2</sub> is reported and the decomposition is fully characterized in a combination of diffraction and thermogravimetric studies. The bulk properties of γ-Mg(BH<sub>4</sub>)<sub>2</sub> are compared to those of an SiO<sub>2</sub> isostructure and probed by various neutron scattering techniques. Negative thermal expansion is observed at low temperatures and the material absorbs up to 1.5 moles of hydrogen gas to form one of the most gravimetrically hydrogen-dense materials ever reported. The structural evolution of Ca(BH<sub>4</sub>)<sub>2</sub> under different synthetic conditions and external influences (e.g. temperature) is studied up until the material decomposes. The effects of various additives on group II metal borohydrides are also examined and the influence of each is justified by observing subtle structural changes in the mixed system via <em>in situ</em> synchrotron X-ray powder diffraction and <sup>11</sup>B NMR measurements.</p>
spellingShingle Crystallography
Hydrogen Storage
Solid state chemistry
Structural chemistry
Inorganic chemistry
Chemical crystallography
Atomic scale structure and properties
Culligan, SD
The crystal chemistry and hydrogen storage properties of light metal borohydrides
title The crystal chemistry and hydrogen storage properties of light metal borohydrides
title_full The crystal chemistry and hydrogen storage properties of light metal borohydrides
title_fullStr The crystal chemistry and hydrogen storage properties of light metal borohydrides
title_full_unstemmed The crystal chemistry and hydrogen storage properties of light metal borohydrides
title_short The crystal chemistry and hydrogen storage properties of light metal borohydrides
title_sort crystal chemistry and hydrogen storage properties of light metal borohydrides
topic Crystallography
Hydrogen Storage
Solid state chemistry
Structural chemistry
Inorganic chemistry
Chemical crystallography
Atomic scale structure and properties
work_keys_str_mv AT culligansd thecrystalchemistryandhydrogenstoragepropertiesoflightmetalborohydrides
AT culligansd crystalchemistryandhydrogenstoragepropertiesoflightmetalborohydrides