Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 22: Materials for Energy Storage and Conversion

MM 22.10: Talk

Wednesday, April 3, 2019, 12:45–13:00, H43

A first-principles based LATP force-field for grain-boundary simulations — Simon Rittmeyer¹, Karsten Reuter¹, Rüdiger Eichel², and •Christoph Scheurer¹ — ¹Theoretische Chemie, TU München — ²IEK-9, FZ Jülich

Superionic lithium-ion conductors of NASICON structure are promising solid-state electrolytes (SSE) for all solid-state batteries (ASSB). A detailed multi-modal experimental analysis of carefully sintered Li_1+xAl_xTi_2−x(PO₄)₃ (LATP, x=0.3) has yielded interesting structural insights and a surprisingly lower ionic conductivity in the amorphous grain boundary interphase than in the grain bulk.[1] Combined with high cycling stability observed in a LATP-based phosphate-backbone ASSB, these findings call for a detailed microscopic understanding. We have constructed a first-principles based force-field which covers stoichiometries x=0… 0.3 and sampled surface slab models representing possible LATP mixed occupancies. DFT computations on large surface models yield first insights into the mechanisms behind the peculiar properties of this material.

[1] A. Mertens, S. Yu, N. Schön, D. Guenduez, H. Tempel, R. Schierholz, F. Hausen, H. Kungl, J. Granwehr, and R. Eichel, Solid state ionics 309 (2017), 180.