The theoretical evaluation of new promising solid ion conductors for zinc-ion batteries

Abstract

Recently, we have screened the Inorganic Crystal Structure Database (ICSD, version 2020/1) to find new Zn2+-ion conductors. After a stepwise selection procedure, we have identified five most promising Zn-ion conductors ZnFe2O4, ZnV2O4, ZnCr2O4, ZnP2O6 and Zn3S2O9. In this work we describe the ion conductivity in the selected structures in detail by using of a set of methods: analysis of free space in crystals (geometrical-topological analysis, based on the Voronoi partitioning approach), calculation of the Zn2+-ion migration energy barrier within the bond valence site energy method, and calculation of the Zn2+-ion energy barriers within the density functional theory approach.