High-throughput screening of solid-state Li-ion conductors using lattice-dynamics descriptors

Sokseiha Muy, Johannes Voss, Roman Schlem, Raimund Koerver, Stefan J. Sedlmaier, Filippo Maglia, Peter Lamp, Wolgang G. Zeier, Yang Shao-Horn
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Low lithium-ion migration barriers have recently been associated with low average vibrational fre-quencies or phonon band centers, further helping identify descriptors for superionic conduction. To further explore this correlation, here we present the computational screening of 14,000 Li-contain-ing compounds in the Materials Project database using a descriptor based on lattice dynamics re-ported recently to identify new promising Li-ion conductors. An efficient computational approach was optimized to compute the average vibrational frequency or phonon band center of 1,200 com-pounds obtained after pre-screening based on structural stability, band gap, and their composition. Combining a low computed Li phonon band center with large computed electrochemical stability window and structural stability, 18 compounds were predicted to be promising Li-ion conductors, one of which, Li3ErCl6, has been synthesized and exhibits a reasonably high room-temperature conductivity of 0.05–0.3 mS/cm, which shows the promise of Li-ion conductor discovery based on lattice dynamics.

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