Li-ion diffusion in Li 4 Ti 5 O 12 and LiTi 2 O 4 battery materials detected by muon spin spectroscopy
Li-ion diffusion in Li 4 Ti 5 O 12 and LiTi 2 O 4 battery materials detected by muon spin spectroscopy
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DOI：
10.1103/physrevb.92.014417
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发表时间：
2015-07
影响因子：
3.7
通讯作者：
J. Sugiyama;H. Nozaki;I. Umegaki;K. Mukai;K. Miwa;S. Shiraki;T. Hitosugi;A. Suter;T. Prokscha
中科院分区：
文献类型：
--
作者：
J. Sugiyama;H. Nozaki;I. Umegaki;K. Mukai;K. Miwa;S. Shiraki;T. Hitosugi;A. Suter;T. Prokscha
尖晶石${\mathrm{Li}}_{4}{\mathrm{Ti}}_{5}{\mathrm{O}}_{12}$和${\mathrm{LiTi}}_{2}{\mathrm{O}}_{4}$化合物中用于未来电池应用的锂扩散已通过μ介子自旋弛豫(${\ensuremath{\mu}}^{+}\mathrm{SR})$进行了研究。在 25 至 500 K 的温度范围内对薄膜和粉末样品进行测量。对于 ${\mathrm{Li}}_{4}{\mathrm{Ti}}_{5}{\mathrm{O}}_{12}$ 及以上约 $\ensuremath{\sim}200\phantom{\rule{0.28em}{0ex}}\mathrm{K}$，场分布宽度发现 ($\mathrm{\ensuremath{\Delta}})$ 逐渐减小，而场波动率 ($\ensuremath{\nu})$ 随着温度呈指数增加。相反，对于 ${\mathrm{LiTi}}_{2}{\mathrm{O}}_{4}$，$\mathrm{\ensuremath{\Delta}}(T)$ 曲线在 $\ensuremath{\sim}350\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ 处呈阶梯式下降，围绕该值$\ensuremath{\nu}(T)$ 曲线呈现局部最大值。这些行为表明，对于两种尖晶石，${\mathrm{Li}}^{+}$ 在 200 K 左右开始扩散。假设从四面体 $8a$ 位点到空八面体 $16c$ 位点的 ${\mathrm{Li}}^{+}$ 跳跃扩散，薄膜样品中 300 K 温度下 ${\mathrm{Li}}^{+}$ 的扩散系数估计为$(3.2\ifmmode\pm\else\textpm\fi{}0.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11} {\mathrm{cm}}^{2}$/s，${\mathrm{Li}}_{4}{\mathrm{Ti}}_{5}{\mathrm{O}}_{12}$ 和$(3.6\ifmmode\pm\else\textpm\fi{}1.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11} {\mathrm{cm}}^{2}$/s，${\mathrm{LiTi}}_{2}{\mathrm{O}}_{4}$。此外，粉末和薄膜样品之间的热活化能和锂离子扩散系数也存在一些细微的差异。
Lithium diffusion in spinel ${\mathrm{Li}}_{4}{\mathrm{Ti}}_{5}{\mathrm{O}}_{12}$ and ${\mathrm{LiTi}}_{2}{\mathrm{O}}_{4}$ compounds for future battery applications has been studied with muon spin relaxation (${\ensuremath{\mu}}^{+}\mathrm{SR})$. Measurements were performed on both thin-film and powder samples in the temperature range between 25 and 500 K. For ${\mathrm{Li}}_{4}{\mathrm{Ti}}_{5}{\mathrm{O}}_{12}$ and above about $\ensuremath{\sim}200\phantom{\rule{0.28em}{0ex}}\mathrm{K}$, the field distribution width ($\mathrm{\ensuremath{\Delta}})$ is found to decrease gradually, while the field fluctuation rate ($\ensuremath{\nu})$ increases exponentially with temperature. For ${\mathrm{LiTi}}_{2}{\mathrm{O}}_{4}$, on the contrary, the $\mathrm{\ensuremath{\Delta}}(T)$ curve shows a steplike decrease at $\ensuremath{\sim}350\phantom{\rule{0.28em}{0ex}}\mathrm{K}$, around which the $\ensuremath{\nu}(T)$ curve exhibits a local maximum. These behaviors suggest that ${\mathrm{Li}}^{+}$ starts to diffuse above around 200 K for both spinels. Assuming a jump diffusion of ${\mathrm{Li}}^{+}$ at the tetrahedral $8a$ site to the vacant octahedral $16c$ site, diffusion coefficients of ${\mathrm{Li}}^{+}$ at 300 K in the film samples are estimated as $(3.2\ifmmode\pm\else\textpm\fi{}0.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11} {\mathrm{cm}}^{2}$/s for ${\mathrm{Li}}_{4}{\mathrm{Ti}}_{5}{\mathrm{O}}_{12}$ and $(3.6\ifmmode\pm\else\textpm\fi{}1.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11} {\mathrm{cm}}^{2}$/s for ${\mathrm{LiTi}}_{2}{\mathrm{O}}_{4}$. Further, some small differences are found in both thermal activation energies and Li-ion diffusion coefficients between the powder and thin-film samples.