Lithium‐Ion Mobility in Layered Oxide Li 2 (La 0.75 Li 0.25 )(Ta 1.5 Ti 0.5 )O 7 Containing Lithium on both Intra and Inter‐Stack Positions
Lithium‐Ion Mobility in Layered Oxide Li 2 (La 0.75 Li 0.25 )(Ta 1.5 Ti 0.5 )O 7 Containing Lithium on both Intra and Inter‐Stack Positions
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叠层内和叠间位置均含锂的层状氧化物 Li 2 (La 0.75 Li 0.25 )(Ta 1.5 Ti 0.5 )O 7 中的锂离子迁移率
DOI：
10.1002/ejic.202100950
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发表时间：
2022
影响因子：
2.3
通讯作者：
Ramezanipour, Farshid
中科院分区：
文献类型：
--
作者：
Fanah, Selorm Joy;Ramezanipour, Farshid
借助于中子衍射和电化学阻抗谱，我们证明了锂浓度和分布的增加对锂离子电导率的影响。这是通过合成层状氧化物Li 2（La0.75Li0.25）（Ta1.5Ti0.5）O 7来实现的，其具有所谓的Ruddlesden-Popper型结构，其中（Ta/Ti）O 6八面体的双层堆叠被位于堆叠间空间的锂离子隔开。也有堆内空间被La和Li的混合物占据，如中子衍射所证实的。锂在叠层间和叠层内位置上的分布导致Li 2（La0.75Li0.25）（Ta1.5Ti0.5）O 7中的锂离子电导率与Li 2La（TaTi）O 7相比增强，Li 2La（TaTi）O 7具有较低的锂离子浓度，仅位于叠层间空间中。电化学阻抗数据的真实的和虚部的分析证实了在Li 2（La 0.75 Li 0.25）（Ta 1.5 Ti 0.5）O 7中离子的迁移率增强。虽然锂离子电导率在实际应用中需要进一步改进，但这项工作中实施的策略的成功为分层离子导体的设计提供了一种有用的方法。
With the aid of neutron diffraction and electrochemical impedance spectroscopy, we have demonstrated the effect of the increase in lithium concentration and distribution on Li‐ion conductivity. This has been done through the synthesis of a layered oxide Li2(La0.75Li0.25)(Ta1.5Ti0.5)O7, with the so‐called Ruddlesden‐Popper type structure, where bilayer stacks of (Ta/Ti)O6octahedra are separated by lithium ions, located in inter‐stack spaces. There are also intra‐stack spaces that are occupied by a mixture of La and Li, as confirmed by neutron diffraction. The distribution of lithium over both inter‐ and intra‐stack positions leads to the enhancement of Li‐ion conductivity in Li2(La0.75Li0.25)(Ta1.5Ti0.5)O7compared to Li2La(TaTi)O7, which has a lower concentration of lithium ions, located only in inter‐stack spaces. The analyses of real and imaginary components of electrochemical impedance data confirm the enhanced mobility of ions in Li2(La0.75Li0.25)(Ta1.5Ti0.5)O7. While the Li‐ion conductivity needs further improvement for practical applications, the success of the strategy implemented in this work offers a useful methodology for the design of layered ionic conductors.