Crystal structure, sinterability and electrical conductivity of proton conducting Ba-1 (-) xSrxZr0.9Y0.1O3 (-) (delta) were investigated. Crystal structure varies from cubic, tetragonal, body-centered orthorhombic to primitive orthorhombic with increasing Sr content, which shows the same tendency with Ba1 - xSrxZrO3. With Sr substitution, sinterability and grain growth of Ba-1 (-) xSrxZr0.9Y0.1O3 (-) (delta) increase and sintering density more than 92% is realized for the ceramic specimens with x >= 0.4 even at sintering temperature of 1600 degrees C. Due to improvement of sinterability and grain growth, the electrical conductivity at grain boundary is enhanced by Sr substitution, resulting in total electrical conductivity of Ba0.6Sr0.4Zr0.9Y0.1O3 (-) (delta) high. The improvement of bulk electrical conductivity is also observed by Sr substitution, suggesting high potential as superior proton conductor in Ba0.6Sr0.4Zr0.9Y0.1O3 (-) delta. (C) 2014 Elsevier B.V. All rights reserved.