And Yet It Moves: A High-Temperature Neutron Diffraction Study of Ion Diffusion in the Inverse Perovskites BaLi𝘟₃ (𝘟 = F, H, D)

Abstract

Despite the interest in (anti-)perovskites and diverse hydrides as hydride conductors and all-solid-state battery materials, little experimental evidence on anion diffusion in these compounds is available. Herein, we use neutron diffraction at high temperatures to discover pathways and estimate activation barriers of anion migration in mechanosynthesized powders of BaLiF₃, BaLiH₃, and BaLiD₃. We critically assess the limitations of both current methods for deriving effective one-particle potentials (i.e., via modelling of the probability-density function and via maximum-entropy reconstruction of the scatterer density). The suggested migration pathways run roughly along the edges of the LiX₆ octahedra with activation energies of 0.45(3), ca. 0.41, and less than 1.44(3) eV in BaLiD₃, BaLiH₃, and BaLiF₃, respectively. Not only is this the first determination of diffusion barriers in these hydrides but also the second study providing any comparative data on the two methods of derivation.

Dr. Dennis Wiedemann

Technischer Berater für Umweltfragen
Chemiker · Kristallograph

Ich bin promovierter Chemiker und berate zu immissionsschutz- und wasserrechtlichen Genehmigungsfragen.