Prediction of oxygen ion conduction from relative Coulomb electronic interactions in oxyapatites

▶ We develop a mathematical model, i.e., a linear relation of ionic conductivities and the relative Coulomb's energy, to predict the ionic conductivities of oxyapatites. ▶ The inputs to the model are two elemental properties of ionic radius and electronegativity of the constituent elements. ▶ We study the effects of the two elemental properties on ionic conductivity. ▶ We predict a wide range of new oxygen stoichiometric oxyapatites with ionic conductivities potentially as high as 10−2 - 10−1 S cm−1 at 500 °C. ▶ We suggest an optimization strategy to search for promising oxyapatites, i.e., applying dopants of large ionic radii and low electronegativities.