Synergetic proton conduction in BaZr0.8Y0.2O3 -δ–carbonate composite electrolyte for intermediate-temperature solid oxide fuel cells

•Dense microstructure of the composite electrolyte membrane•Ionic conductivity increases with the partial pressures of H2 and H2O•Proposed a new model for synergetic proton transport

In the present study, electrical properties of a composite electrolyte composed of a BaZr0.8Y0.2O3 -δ (BZY) and a perspective of defect chemistry. A DFT first-principles calculation further confirmed that proton transfer in molten carbonates was a low-energy process.