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MM: Fachverband Metall- und Materialphysik

MM 15: Poster session I

MM 15.21: Poster

Montag, 7. März 2016, 18:00–20:00, Poster B3

Identification of structural bottlenecks for sodium ion transport in solid state sodium ion conductors — •Kaustubh Bhat, Stefan Blügel, and Hans Lustfeld — Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany

Sodium ion conductors offer significant advantages for applications in large scale-energy storage systems. It was observed that the ionic conductivity of NASICON [1] materials is correlated to certain areas that were proposed to be structural bottlenecks to sodium ion transport [2]. We use density functional theory along with the Nudged Elastic Band Method [3] to calculate the energy barrier for transport pathways in the NASICON material sodium scandium phosphate Na₃ Sc₂ ( PO₄ )₃. We apply stress to the crystal to calculate the change of the energy barrier with changing strain [4]. Using a constrained gradient descent method, we quantify the effect of the following structural features on the energy barrier: (a) interatomic distances, (b) areas between neighboring atoms and (c) volumes around mobile ions. This enables us to identify all relevant structural bottlenecks. – We acknowledge fruitful discussions with our experimental colleagues F. Tietz and M. Guin toward this work.

[1] Hong H.Y.P., MRB 11, 173-182 (1976).

[2] Winaud J.M. et al. J.Mater. Sci. 25, 4008-4013 (1990).

[3] Henkelman G. et al. JCP 113, 9901-9904 (2000).

[4] Hirschfeld J.A. et al. PRB 84, 224308 (2011).