A　composite　of　a　perovsldte　oxide　proton　conductor　(BaCe0.7Zr0.1Y0.2O3-delta,　BCZ10Y20)　and　alkali　carbonates　(2Li(2)CO(3):1Na(2)CO(3),　LNC)　is　investigated　with　respect　to　its　morphology,　conductivity　and　fuel　cell　performance.　The　morphology　shows　that　the　presence　of　carbonate　phase　improves　the　densification　of　oxide　matrix.　The　conductivity　is　measured　by　AC　impedance　in　air,　nitrogen,　wet　nitrogen,　hydrogen,　and　wet　hydrogen,　respectively.　A　sharp　increase　of　the　conductivity　at　certain　temperature　is　seen,　which　relates　to　the　superionic　phase　transition　at　the　interface　phases　between　oxide　and　carbonates.　Single　cell　with　the　composite　electrolyte　is　fabricated　by　dry-pressing　technique,　using　nickel　oxide　as　anode　and　lithiated　nickel　oxide　as　cathode,　respectively.　The　cell　shows　a　maximum　power　density　of　957　mW　cm(-2)　at　600　degrees　C　with　hydrogen　as　the　fuel　and　oxygen　as　the　oxidant.　The　remarkable　proton　conductivity　and　excellent　cell　performance　make　this　kind　of　composite　material　a　good　candidate　electrolyte　for　low　temperature　solid　oxide　fuel　cells　(SOFCs).　Copyright　(C)　2014,　Hydrogen　Energy　Publications,　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.