Effect of Sr content on the crystal structure and electrical properties of the system La2−xSrxNiO4+δ (0 ≤ x ≤ 1)

Abstract

Materials formulated as La_2−xSr_xNiO_4+δ (0 ≤ x ≤ 1) have been prepared and investigated by high-resolution neutron powder diffraction in order to correlate the structural variation induced by the incorporation of Sr into the crystal lattice with the electronic and thermal properties of each material. The evolution of the electrical conductivity and thermal expansion coefficients with temperature have been determined in order to study the potential use of these compounds as cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFC). These oxides show a good thermal expansion coefficient (TEC = 11–13 × 10⁻⁶ K⁻¹), and high electronic conductivity up to 273 S cm⁻¹. It is noticeable that a great enhancement of the electrical conductivity with the Sr content is concomitant with the shortening of the Ni–O1 bond length.