Defect chemistry of LaGaO3 doped with divalent cations

Solid oxide fuel cells are highly efficient energy conversion devices and can produce electrical energy from a variety of fuels. One of the main challenges is to decrease its operating temperatures, since the high temperatures currently required for satisfactory oxide-ion conduction at the electrolyte decrease the lifetime of the device. LaGaO3-based materials possess high conductivities in lower temperatures when compared to traditional fluorite-structured materials. In this study, density functional theory calculations were performed to investigate the potential effects of divalent dopants in the ionic conductivity of the perovskite. The most suitable dopants were determined, with steric and electronic effects being found to play a role in how easily these dopants are accepted into the lattice. The distortion of the doped perovskite local structure was observed to be an indicator of the tendency of vacancies to be trapped around dopants, possibly hindering ionic conductivity.