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Motion of Li + in Nanoengineered LiBH 4 and LiBH 4 :Al 2 O 3 Comparison with the Microcrystalline Form
Author(s) -
Epp Viktor,
Wilkening Martin
Publication year - 2013
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201300743
Subject(s) - nanocrystalline material , ion , spins , microcrystalline , relaxation (psychology) , relaxometry , phase (matter) , materials science , chemical physics , chemistry , crystallography , thermodynamics , condensed matter physics , organic chemistry , medicine , psychology , social psychology , physics , spin echo , magnetic resonance imaging , radiology
The introduction of structural disorder and large volume fractions of different kinds of interfaces enables the manipulation of ion dynamics in solids. Variable‐temperature solid‐state NMR relaxometry is highly useful to study Li + jump processes. If carried out as a function of frequency, the resulting NMR relaxation rates also contain information on the dimensionality (1D, 2D, or 3D) of the diffusion process. Recently, NMR relaxometry has revealed the 2D nature of Li hopping in LiBH 4 , and thus this hydride is an interesting ion conductor for further diffusion studies on the spatially confined motion of Li spins. Here, nanocrystalline LiBH 4 and the two‐phase analogue LiBH 4 :Al 2 O 3 , which are prepared by ball milling, serve as interesting model systems to track the changes in NMR relaxation rates with respect to coarse‐grained, thermodynamically stable LiBH 4 . This reveals that interface (nano)engineering influences the hexagonal‐to‐orthorhombic phase transition and thus alters the ion‐transport properties of Li in one‐ and two‐phase LiBH 4 towards higher diffusivities at lower temperatures.