SKM 2023 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 10: Battery Materials (joint session KFM/CPP)
KFM 10.7: Talk
Thursday, March 30, 2023, 11:00–11:20, POT 51
Hypothetical t-LGPO as a good ionic conductor, and the influence of Li core electrons on diffusion — Giuliana Materzanini1, •Nicola Marzari2, 3, and Gian-Marco Rignanese1 — 1Modelling Division, Universite catholique de Louvain, 1348 Louvain-la-Neuve, Belgium — 2Theory and Simulations of Materials (THEOS), Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland — 3National Centre for Computational Design and Discovery of Novel Materials (MARVEL), Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland
Following the computationally found high Li-ion conductivity in tetragonal Li10GeP2O12 (t-LGPO), we study here the role of Li core electrons on Li diffusion in this hypothetical superionic material. We calculate Li diffusivity from two sets of Car-Parrinello canonical molecular dynamics simulations, one using Li pseudopotential with all electrons (1s22s1), and one with just one electron (2s1). The Arrhenius plots show a marked influence of the Li 1s electrons on the Li-ion diffusivity in t-LGPO, being the diffusion coefficient at 600 K one order of magnitude larger, and the activation barrier between 600 and 1200 K 1.5 times smaller, for the Li all-electrons with respect to the Li one-electron calculations. Similar sets of simulations performed for the analogue sulfide material, tetragonal Li10GeP2S12 (LGPS), show, oppositely, that for LGPS the influence of Li 1s electrons on Li diffusivity is minimal. The different response of Li mobility to the explicit treatment of 1s electrons reveals fundamental differences in the ionic conductivity mechanism in these two classes of materials.