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Title: Grain boundary stability and influence on ionic conductivity in a disordered perovskite -- a first-principles investigation of lithium lanthanum titanate

The origin of ionic conductivity in bulk lithium lanthanum titanate, a promising solid electrolyte for Li-ion batteries, has long been under debate, with experiments showing lower conductivity than predictions. Recent microscopy images show Type I and Type II grain boundaries. Using first-principles based calculations we find that experimentally observed Type I boundaries are more stable compared to the Type II grain boundaries, consistent with their observed relative abundance. Grain boundary stability appears to strongly anti-correlate with the field strength as well as the spatial extent of the space charge region. Ion migration is faster along Type II grain boundaries than across, consistent with recent experiments of increased conductivity when Type II densities were increased.
Authors:
 [1] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [3]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Div.
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
MRS Communications
Additional Journal Information:
Journal Volume: 6; Journal Issue: 04; Journal ID: ISSN 2159-6859
Publisher:
Materials Research Society - Cambridge University Press
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1393870