Protonic diffusion and conduction in Gd-doped BaCeO3 were studied by kinetic Monte Carlo simulations using transition rates deduced from previous ab initio calculations. The dopants behaved like shallow traps for the protonic defects, alumina but at low doping concentrations, their presence did not reduce the diffusion coefficient, and the activation energy (≈ 0.36eV) was not significantly affected by the doping rate. This result was tentatively explained by an interplay between the creation of traps consecutive to doping, and the removal of obstacles in the primitive protonic energy landscape, keeping in mind that the present model neglects the increase in attraction between protons and dopants when the dopant concentration increased. The protonic mobility was computed, under finite applied electric field, and found at ≈ 5.54 x 10-9m2/sV at 600K and at 8.61 x 10-8m2/sV at 1200K. These first results suggested that protonic conduction in Gd-doped BaCeO3 was rather isotropic.

Kinetic Monte Carlo Study of Protonic Diffusion and Conduction in Gd-Doped BaCeO3. J.Hermet, F.Bottin, G.Dezanneau, G.Geneste: Solid State Ionics, 2013, 252, 48-55