Unravelling Charge Carrier Mobility in d0‐Metal‐based Spinels

Abstract

AbstractEnabling high Mg ion mobility, spinel‐type materials are promising candidates for cathode or solid electrolyte applications. To elucidate the factors governing the observed high mobility of multivalent ions, periodic DFT calculations of various charge carriers (A=Li, Na, K, Mg, Ca, Zn and Al) in the ASc2S4 and ASc2Se4 spinel compounds were performed, resulting in the identification of a Brønsted‐Evans‐Polanyi‐type scaling relation for the migration barriers of the various charge carriers. Combining this scaling relation with the derivation of a descriptor, solely based on easily accessible observables, constitutes a conceptual framework to investigate ion mobility in d0‐metal‐based spinel chalcogenides with significantly reduced computational effort. This approach was exemplarily verified for various d0‐metal‐based spinel chalcogenide compounds AB2X4 (B=Sc, Y, Ga, In, Er and Tm; X=O, S and Se) and led to the identification of d0‐metal‐based CaB2O4 spinels as promising compounds possibly enabling high Ca ion mobility.