Local Structure and Dynamics of Lithium Garnet Ionic
Conductors: A Model Material Li<sub>5</sub>La<sub>3</sub>Ta<sub>2</sub>O<sub>12</sub>
Yuxing Wang
Matthew Klenk
Katharine Page
Wei Lai
10.1021/cm502133c.s001
https://acs.figshare.com/articles/journal_contribution/Local_Structure_and_Dynamics_of_Lithium_Garnet_Ionic_Conductors_A_Model_Material_Li_sub_5_sub_La_sub_3_sub_Ta_sub_2_sub_O_sub_12_sub_/2245354
In
this article, we combined two complementary structure/dynamics
probes, i.e., total-scattering/reverse Monte Carlo (RMC) modeling
and classical molecular dynamics (MD), in order to understand local
lithium structure and dynamics in a model disordered garnet oxide
Li<sub>5</sub>La<sub>3</sub>Ta<sub>2</sub>O<sub>12</sub>. By examining
the configurations from RMC and trajectories from MD, we individually
and statistically analyzed the lithium distribution and dynamics within
tetrahedral (Td) cages, octahedral (Oh) cages, and triangular bottlenecks.
We found that lithium atoms within either Td or Oh cages prefer to
stay at the off-center positions and close to one of the triangular
bottlenecks. This is likely caused by the uneven Li–Li interaction
in the form of lithium clusters, and such geometrical frustration
leads to the local structure instability and fast ionic conduction.
Both RMC and MD studies support that the lithium conduction path goes
through the triangular bottleneck in a 3D continuous network of Td/Oh
cages, without a direct Oh to Oh jump. However, the conduction mechanism
should not be generalized, as it is greatly influenced by the local
environment or temperature. Broadly speaking, lithium atoms hop through
the bottleneck from an edge-passing mechanism at low temperatures
to a center-passing mechanism at higher temperatures.
2014-10-14 00:00:00
lithium conduction path
lithium atoms
lithium atoms hop
dynamic
garnet oxide Li 5La
Td
lithium distribution
lithium structure
lithium clusters
RMC
bottleneck
conduction mechanism
Lithium Garnet
MD studies support
cage
3 D
structure instability
Local Structure
Model Material Li 5La