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Diffusion mechanism in the superionic conductor Li 4 PS 4 I studied by first-principles calculations

Sicolo, Sabrina and Kalcher, Constanze and Sedlmaier, Stefan J. and Janek, Jürgen and Albe, Karsten (2018):
Diffusion mechanism in the superionic conductor Li 4 PS 4 I studied by first-principles calculations.
In: Solid State Ionics, pp. 83-91, 319, ISSN 01672738,
DOI: 10.1016/j.ssi.2018.01.046,
[Online-Edition: https://doi.org/10.1016/j.ssi.2018.01.046],
[Article]

Abstract

Li_4PS_4I was recently discovered as a novel crystalline lithium ion conductor by applying a soft chemistry approach. It adopts a tetragonal structure type suggesting a three-dimensional migration pathway favorable for a high conductivity [S.J. Sedlmaier, Chem. Mater. 29 (2017) 1830]. Especially in view of the highly connected pathways for Li motion within a simple anion sublattice formed by PS_[4]^[3-] and iodine anions, the conductivity measured from both impedance spectroscopy and NMR data appears to be rather small, and a negative influence of impurities and of grain boundaries effects was assumed. In order to shed light on the full potential of this material, we performed a theoretical study of Li_4PS_4I in the framework of density functional theory. After creating a structural model that accurately accounts for the partial occupancies determined by diffraction experiments, we performed molecular dynamics simulations, unraveled the diffusion mechanisms and calculated diffusion coefficients and the activation barrier for diffusion. The results of the theoretical study on both a crystalline and a glassy supercell imply that Li_4PS_4I is in fact a superionic conductor with a much higher conductivity than reported so far.

Item Type: Article
Erschienen: 2018
Creators: Sicolo, Sabrina and Kalcher, Constanze and Sedlmaier, Stefan J. and Janek, Jürgen and Albe, Karsten
Title: Diffusion mechanism in the superionic conductor Li 4 PS 4 I studied by first-principles calculations
Language: English
Abstract:

Li_4PS_4I was recently discovered as a novel crystalline lithium ion conductor by applying a soft chemistry approach. It adopts a tetragonal structure type suggesting a three-dimensional migration pathway favorable for a high conductivity [S.J. Sedlmaier, Chem. Mater. 29 (2017) 1830]. Especially in view of the highly connected pathways for Li motion within a simple anion sublattice formed by PS_[4]^[3-] and iodine anions, the conductivity measured from both impedance spectroscopy and NMR data appears to be rather small, and a negative influence of impurities and of grain boundaries effects was assumed. In order to shed light on the full potential of this material, we performed a theoretical study of Li_4PS_4I in the framework of density functional theory. After creating a structural model that accurately accounts for the partial occupancies determined by diffraction experiments, we performed molecular dynamics simulations, unraveled the diffusion mechanisms and calculated diffusion coefficients and the activation barrier for diffusion. The results of the theoretical study on both a crystalline and a glassy supercell imply that Li_4PS_4I is in fact a superionic conductor with a much higher conductivity than reported so far.

Journal or Publication Title: Solid State Ionics
Volume: 319
Uncontrolled Keywords: Density functional theory, Li-ion batteries, Solid electrolyte, Superionic conductor
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ) > Hochleistungsrechner
11 Department of Materials and Earth Sciences > Material Science
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ)
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
Date Deposited: 01 Mar 2018 09:46
DOI: 10.1016/j.ssi.2018.01.046
Official URL: https://doi.org/10.1016/j.ssi.2018.01.046
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