Ba0.5Sr0.5Ce0.6Zr0.2Gd0.1Y0.1O3 - delta (BSCZGY) proton conducting electrolyte material for intermediate temperature solid oxide fuel cells (IT-SOFC5) has been synthesized by a sol-gel modified Pechini process and its sinterability, thermal expansion, microstructure, ionic conductivity and chemical stability have been investigated. Ionic conductivity at 700 degrees C was measured to be similar to 8 x 10(-3) S cm(-3) in wet 5 vol.% H2/Ar atmospheres. Chemical stability test in pure CO2 up to 1200 degrees C shows that the material is highly stable; better than the stability of BaZr0.3Ce0.5Y0.1Yb0.1O3 - delta Crown Copyright (C) 2017 Published by Elsevier B.V. All rights reserved.