1 research outputs found
Native Defects in Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> and Their Effect on Lithium Diffusion
Defects
in crystals alter the intrinsic nature of pristine materials
including their electronic/crystalline structure and charge-transport
characteristics. The ionic transport properties of solid-state ionic
conductors, in particular, are profoundly affected by their defect
structure. Nevertheless, a fundamental understanding of the defect
structure of one of the most extensively studied lithium superionic
conductors, Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, remains
elusive because of the complexity of the structure; the effects of
defects on lithium diffusion and the potential to control defects
by varying synthetic conditions also remain unknown. Herein, we report,
for the first time, a comprehensive first-principles study on native
defects in Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> and their
effect on lithium diffusion. We provide the complete defect profile
of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> and identify major
defects that are easily formed regardless of the chemical environment
while the presence of path-blocking defects is sensitively dependent
on the synthetic conditions. Moreover, using <i>ab initio</i> molecular dynamics simulation, it is demonstrated that the major
defects in Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> significantly
alter the diffusion process. The defects generally facilitate lithium
diffusion in Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> by enhancing
the charge carrier concentration and flattening the site energy landscape.
This work delivers a comprehensive picture of the defect chemistry
and structural insights for fast lithium diffusion of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>-type conductors