From ultraslow to fast lithium diffusion in the 2D ion conductor Li0.7TiS2 probed directly by stimulated-echo NMR and nuclear magnetic relaxation.
From ultraslow to fast lithium diffusion in the 2D ion conductor Li0.7TiS2 probed directly by stimulated-echo NMR and nuclear magnetic relaxation.
复制标题
DOI：
10.1103/physrevlett.97.065901
复制
发表时间：
2006-08
影响因子：
8.6
通讯作者：
M. Wilkening;W. Küchler;P. Heitjans
中科院分区：
文献类型：
--
作者：
M. Wilkening;W. Küchler;P. Heitjans
7 Li受激回波NMR和经典弛豫NMR技术联合使用的第一次全面调查锂扩散层状结构的Li0.7TiS2。一个单一的2D锂扩散过程中探测了近10个数量级的动态范围。到目前为止，这是直接通过7 Li NMR光谱测量的最大动态范围，即，没有特定的理论模型的帮助。跃迁速率服从严格的Arrhenius定律，由活化能0.41（1）eV和指前因子6.3（1）× 10（12）s-1确定，范围在1 × 10（-1）s-1和7.8 × 10（8）s-1（148-510 K）之间。通过记录7 Li自旋对准相关函数，直接测量了kHz至子Hz范围内的超低Li跳跃。的温度，特别是，频率依赖性的弛豫速率完全同意预期的2D扩散的结果。
7Li stimulated-echo NMR and classical relaxation NMR techniques are jointly used for the first time for a comprehensive investigation of Li diffusion in layer-structured Li0.7TiS2. One single 2D Li diffusion process was probed over a dynamic range of almost 10 orders of magnitude. So far, this is the largest dynamic range being measured by 7Li NMR spectroscopy directly, i.e., without the help of a specific theoretical model. The jump rates obey a strict Arrhenius law, determined by an activation energy of 0.41(1) eV and a preexponential factor of 6.3(1)x10(12) s-1, and range between 1x10(-1) s-1 and 7.8x10(8) s-1 (148-510 K). Ultraslow Li jumps in the kHz to sub-Hz range were measured directly by recording 7Li spin-alignment correlation functions. The temperature and, in particular, the frequency dependence of the relaxation rates fully agree with results expected for 2D diffusion.