Issue 47, 2014

Order vs. disorder—a huge increase in ionic conductivity of nanocrystalline LiAlO2 embedded in an amorphous-like matrix of lithium aluminate

Abstract

Coarse grained, well crystalline γ-LiAlO2 (P43212) is known as an electronic insulator and a very poor ion conductor with the lithium ions occupying tetrahedral voids in the oxide structure. The introduction of structural disorder such as point defects or higher-dimensional defects, however, may greatly affect ionic conduction on both short-range as well as long-range length scales. In the present study, we used high-energy ball milling to prepare defect-rich, nanocrystalline LiAlO2 that was characterized from a structural point of view by powder X-ray diffraction, TEM as well as small angle X-ray scattering (SAXS). Temperature-dependent conductivity spectroscopy revealed an increase of the room-temperature ionic conduction by several orders of magnitude when going from microcrystalline γ-LiAlO2 to its nanocrystalline form. The enhanced ion transport found is ascribed to the increase of Li ions near defective sites both in the bulk as well as in the large volume fraction of interfacial regions in nano-LiAlO2. The nanocrystalline ceramic prepared at long milling times is a mixture of γ-LiAlO2 and the high-pressure phase δ-LiAlO2; it adapts an amorphous like structure after it has been treated in a planetary mill under extremely harsh conditions.

Graphical abstract: Order vs. disorder—a huge increase in ionic conductivity of nanocrystalline LiAlO2 embedded in an amorphous-like matrix of lithium aluminate

Article information

Article type
Paper
Submitted
10 Jun 2014
Accepted
12 Oct 2014
First published
13 Oct 2014
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2014,2, 20295-20306

Author version available

Order vs. disorder—a huge increase in ionic conductivity of nanocrystalline LiAlO2 embedded in an amorphous-like matrix of lithium aluminate

D. Wohlmuth, V. Epp, P. Bottke, I. Hanzu, B. Bitschnau, I. Letofsky-Papst, M. Kriechbaum, H. Amenitsch, F. Hofer and M. Wilkening, J. Mater. Chem. A, 2014, 2, 20295 DOI: 10.1039/C4TA02923B

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements