Sparse Cyclic Excitations Explain the Low Ionic Conductivity of Stoichiometric Li7La3Zr2 O12

Mario Burbano, Dany Carlier, Florent Boucher, Benjamin J. Morgan, Mathieu Salanne

Research output: Contribution to journalArticlepeer-review

32 Citations (SciVal)

Abstract

We have performed long time scale molecular dynamics simulations of the cubic and tetragonal phases of the solid lithium-ion electrolyte Li7La3Zr2O12 (LLZO), using a first-principles parametrized interatomic potential. Collective lithium transport was analyzed by identifying dynamical excitations: persistent ion displacements over distances comparable to the separation between lithium sites, and stringlike clusters of ions that undergo cooperative motion. We find that dynamical excitations in c-LLZO (cubic) are frequent, with participating lithium numbers following an exponential distribution, mirroring the dynamics of fragile glasses. In contrast, excitations in t-LLZO (tetragonal) are both temporally and spatially sparse, consisting preferentially of highly concerted lithium motion around closed loops. This qualitative difference is explained as a consequence of lithium ordering in t-LLZO and provides a mechanistic basis for the much lower ionic conductivity of t-LLZO compared to c-LLZO.

Original languageEnglish
Article number135901
Pages (from-to)1 - 6
Number of pages6
JournalPhysical Review Letters
Volume116
Issue number13
DOIs
Publication statusPublished - 30 Mar 2016

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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