Crystal Structure and Diffusion Path in the Fast Lithium-Ion Conductor La0.62Li0.16TiO3
Crystal Structure and Diffusion Path in the Fast Lithium-Ion Conductor La0.62Li0.16TiO3
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DOI：
10.1021/ja0449224
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发表时间：
2005-02
影响因子：
15
通讯作者：
M. Yashima;M. Itoh;Y. Inaguma;Y. Morii
中科院分区：
文献类型：
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作者：
M. Yashima;M. Itoh;Y. Inaguma;Y. Morii
本文报道了La0.62Li0.16TiO3钙钛矿的中子粉末衍射研究结果，确定了锂离子在室温下的扩散路径。在77 K时，Li离子位于（002）La亏缺层上的2c位点（Cmmm空间群的Wycoff符号），而在室温下，它们分布在广泛的区域，并沿着（002）层上的2c - 4f - 2c或2c - 2d - 2c tie线迁移。Li阳离子的概率密度在2c和4f之间或2c和2d之间的扩散路径上的位置之间具有最小值，与之前的报告相反，瓶颈被认为位于2c， 2d和4f位置。在现有结构模型的基础上，用二维键-渗模型讨论了锂离子的电导率。研究发现，La位的空位对于锂离子的传导是必不可少的。
We report the results of a neutron powder diffraction study of the La0.62Li0.16TiO3 perovskite that determined the diffusion path of lithium cations at room temperature. At 77 K, the Li cations are located at the 2c site (Wycoff notation of the Cmmm space group) on the (002) La deficient layer, while, at room temperature, they are spread over a wide area and migrate following the 2c−4f−2c or 2c−2d−2c tie line on the (002) layer. The probability density of Li cations has a minimum between the 2c and 4f or between the 2c and 2d positions on the diffusion path in contrast to the previous reports where the bottleneck has been thought to be located at the 2c, 2d, and 4f positions. On the basis of the present structural model, the Li-cation conductivity is discussed in terms of a two-dimensional bond-percolation model for Li-cation diffusion. It was found that the vacancy at the La site is essential for the Li-cation conduction.