Grain Boundaries in a Lithium Aluminum Titanium Phosphate-Type Fast Lithium Ion Conducting Glass Ceramic: Microstructure and Nonlinear Ion Transport Properties

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• 作者：Michael Gellert ; Katharina I. Gries ; Chihiro Yada ; Fabio Rosciano ; Kerstin Volz ; Bernhard Roling
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 1, 2012
• 年：2012
• 卷：116
• 期：43
• 页码：22675-22678
• 全文大小：292K
• 年卷期：v.116,no.43(November 1, 2012)
• ISSN：1932-7455

文摘

The structure and lithium ion transport properties of grain boundaries in the Ohara lithium-ion conductive glass ceramic (LI-CGC) were studied by means of nonlinear impedance spectroscopy and high-resolution transmission electron microscopy (HR-TEM). Ac voltages up to 0.8 V (rms) per single boundary could be applied without any irreversible changes of the lithium ion transport properties. Although the activation energy of the grain boundary resistance is only 30 meV higher than the activation energy of the grain resistance, large ac voltages >500 mV per single grain boundary were needed for reducing the grain boundary resistance to a level similar to the grain resistance. Consequently, we argue that the higher activation energy of the grain boundary resistance is not caused by a single barrier (e.g., a single space charge barrier), but by a number of serial barriers. By comparing the nonlinear grain boundary conductivity of the LI-CGC with that of other thin ion conducting layers, we estimate an average electrical grain boundary thickness of 7.5 nm. The HR-TEM images indicate that layers with a thickness in this range exist between grains with similar crystal lattice orientations.