A series of (pseudo)cubic perovskites, $AB{\text{O}}_3$, have been investigated using density functional theory calculations. The structures have been optimized and thermodynamic properties and activation energies for the relevant steps of the hydrogen/proton diffusion mechanism have been calculated using the nudged elastic band path technique. We find a strong correlation between the O-H binding energy for hydrogen/proton uptake in perovskites and the energy barriers involved in the observed Grotthuss-type diffusion process. We demonstrate the possibility of estimating diffusion rates based on O-H binding energy and temperature only, without determining transition states and vibrational frequencies. We determine the binding energy providing the optimal tradeoff between occupation and diffusion rate at a given temperature, and finally we show how these correlations can be used to suggest candidate materials with improved kinetic properties for potential application as hydrogen permeable membranes and proton-conducting electrolytes.

• Received 1 October 2009

DOI:https://doi.org/10.1103/PhysRevB.82.014103