The Effect of Co-Doping at the A-Site on the Structure and Oxide Ion Conductivity in (Ba(0.5−x)Sr(x))La(0.5)InO(3−δ): A Molecular Dynamics Study

A molecular dynamics simulation was used to investigate the structural and transport properties of a (Ba(0.5−x)Sr(x))La(0.5)InO(3−δ) (x = 0, 0.1, 0.2) oxygen ion conductor. Previous studies reported that the ionic conductivity of Ba-doped LaInO(3) decreases because Ba dopant forms a narrow oxygen path in the lattice, which could hinder the diffusion of oxygen ions. In this study, we reveal the mechanism to improve ionic conductivity by Ba and Sr co-doping on an La site in LaInO(3) perovskite oxide. The results show that the ionic conductivity of (Ba(0.5−x)Sr(x))La(0.5)InO(3−δ) increases with an increasing number of Sr ions because oxygen diffusion paths which contain Sr ions have a larger critical radius than those containing Ba ions. The radial distribution function (RDF) calculations show that the peak heights in compositions including Sr ions were lower and broadened, meaning that the oxygen ions moved easily into other oxygen sites.