Stoichiometry-dependent conductivity in framework ionic conductors

Abstract

Stochastic Langevin dynamics simulation of a one-dimensional model for framework ionic conductors shows competing effects of static lattice potential and ion interactions. For commensurate cases, repulsions decrease the conductivity, whereas for incommensurate systems, Coulomb repulsion partly overcomes lattice potential localization, leading to increased conductivity. A new explanation is offered for the observed behavior of NASICON (${\mathrm{Na}}_3$ ${\mathrm{Zn}}_2$P${\mathrm{Si}}_2$ ${\mathrm{O}}_{12}$), based on the important interparticle correlations.