Phase stability and electrochemical analysis of Nb doped BaCe 0.9Y0.1O3-x electrolyte for IT-SOFCs

Abstract

Barium cerate-based electrolytes containing different amounts of Nb 5+ as a dopant were investigated with the aim of attaining materials with improved chemical stability. BaCe0.9.xNbxY 0.1O3-x (BCYN) powders with different compositions (0 ≤ x ≤ 0.20) were synthesized by citrate-nitrate auto-combustion method and pure single phases were obtained at 1000 °C. Dense pellets were obtained using sintering a temperature of 1450 °C for 10 hours. The chemical stability was evaluated by XRD analysis after CO2 exposure at 700°C for 3 hours. To investigate the effect of Nb5+ doping on conductivity, electrochemical impedance spectroscopy (EIS) measurements were carried out in the 400-700 °C temperature range in different atmospheres.