Analysis of Li⁺ cation migration paths in oxygen-containing compounds

Abstract

Novel method for the studying of voids and channels in crystal structures is developed on the basis of the TOPOS structure-topology software. The method is using the Voronoi-Dirichlet crystal space partition. All ternary and quaternary lithium-containing inorganic compounds whose structure has been studied (822 compounds of the Li _a X _b O _z composition and 1349 compounds of the Li _a X1 _b X2 _c O _z composition, where X, X1, and X2 is any chemical element) are analyzed for the first time. The dimensionality of systems of the channels capable of transporting lithium ions is revealed. For all compounds, the migration patterns are constructed, which characterize systems of the conductance channels with the dimensionality 1, 2, and 3; the theoretically calculated coordinates of lithium atom positions in the voids’ centers agree well (accurate within 0.06 nm) with the known structure data. It is found, that 275 compounds have infinite channel system. Of this sampling, 249 compounds (125 structural types) have been described as solid electrolytes; the rest (26 compounds) can be thought of as potential ionic conductors with one-dimensional (6 types), two-dimensional (2 types), or three-dimensional (18 types) conductance.