Study of La0.1Sr0.9TiO3 electrochemical response as anode for solid oxide fuel cells

Abstract

La0.1Sr0.9TiO3 perovskite has been studied as anode material for Intermediate Temperature Solid Oxide Fuel Cell applications. The samples were synthesized by two chemical methods that led to different microstructure. The effect of the microstructure on the electrochemical behavior of the obtained electrodes was studied by Electrochemical Impedance Spectroscopy by varying the hydrogen partial pressure and the temperature. In addition, the evolution of specific area resistance with the hydrogen partial pressure allowed the identification of the reaction mechanism. The obtained results were studied by electrical equivalent circuit and distribution of relaxation times. The results suggest that the hydrogen oxidation reaction limiting step for both samples is controlled by hydrogen dissociative-adsorption at the surface. The hydrogen adsorption is faster at the electrode formed by smaller nanoparticles, in which the activation energy decreases and the rate coefficient changes.