Synthesis, structural and electrical studies of Ba1−xSrxCe0.65Zr0.25Pr0.1O3−δ electrolyte materials for solid oxide fuel cells

Abstract

This paper is discussed Sr doping effect on the microstructure, chemical stability and conductivity of Ba1−xSrxCe0.65Zr0.25Pr0.1O3−δ (0 ≤ x ≤ 0.2) electrolyte prepared by sol–gel method. The lattice constants and unit cell volumes are found to decrease as Sr atomic percentage increased in accordance with the Vegard law, confirming the formation of solid solution with orthorhombic structure. Among them all the synthesized samples are showed a conductivity with different atmosphere values at 500 °C. Ba0.92Sr0.08Ce0.65Zr0.25Pr0.1O3−δ recorded highest conductivity with a value of 3.3 × 10−6 S/cm (dry air) & 3.41 × 10−6 S/cm (wet air with 3% relative humidity) at 500 °C due to its smaller lattice volume, larger grain size and lower activation energy that led to excessive increase in conductivity. All pellets exhibited good chemical stability when exposed to air and H2O atmospheres. This study elucidates that the composition will be a promising electrolyte material for use as SOFC at intermediate temperatures if Sr doping is limited to small amounts. Keywords: Solid oxide fuel cell, Proton conducting electrolyte, Chemical stability, Sol–gel synthesis, BaCeO3