Li^+ Ionic Diffusion in LiCuO2 Exposed to Heating-Cooling Cycles
Li^+ Ionic Diffusion in LiCuO2 Exposed to Heating-Cooling Cycles
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暴露于加热-冷却循环的 LiCuO2 中的 Li^ 离子扩散
DOI：
10.1143/jpsjs.79sa.80
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
and K. Yamada
中科院分区：
文献类型：
--
作者：
K. Nakamura;K. Shimokita;H. Hirano;Y. Michihiro;T. Moriga;and K. Yamada
测量了 LiCuO2 的 7Li NMR 线宽和电导率的温度依赖性，以阐明无序层结构中的 Li+离子扩散。线宽在低于 380 K 左右时保持恒定，而在加热-冷却循环中，在高于 380 K 时观察到由于 Li+离子扩散而导致的线宽变窄。电导率的温度依赖性在第一个加热-冷却循环中表现出滞后现象。它受到高温下产生的 CuO 相引起的外在传导的强烈影响。因此，很难从电导率中提取出本征离子传导。然而，7Li线宽的运动变窄可以用Li+离子跳跃的热激活模型来解释，该模型通过加热-冷却循环产生约0.22 eV的激活能。这表明即使在因暴露于加热-冷却循环而发生结构局部变化的LiCuO2中，也会发生Li+离子扩散。
The temperature dependence of7Li NMR line widths and electrical conductivity of LiCuO2have been measured to elucidate the Li+ionic diffusion in disordered layer structure. The line widths were constant below around 380 K, while the narrowing of line widths attributed to the Li+ionic diffusion was observed above 380 K in a heating-cooling cycle. The temperature dependence of conductivity shows hysteresis in the first heating-cooling cycle. It is strongly affected by the extrinsic conduction induced by the CuO phase produced at high temperatures. Therefore, it is difficult to extract the intrinsic ionic conduction from the electrical conductivity. However, the motional narrowing of7Li line widths is explained with a thermal activation model for Li+ion hopping, which yields the activation energy of around 0.22 eV through the heating-cooling cycle. It indicates that the Li+ionic diffusion occurs even in LiCuO2which has undergone the local change in structure produced by exposure to the heating-cooling cycles.