Zirconium doping effect on the performance of proton-conducting BaZr_yCe_0.8-yY_0.2O_3-δ (0.0 ≤ y ≤ 0.8) for fuel cell applications

High-temperature proton conductors are promising electrolytes for protonic solid oxide fuel cells (H⁺-SOFCs). In this study, the relationship between the Zr doping content and structure, chemical stability, carbon dioxide resistivity, sinterability and electrochemical properties of BaZr_yCe_0.8-yY_0.2O_3-δ (BZCYy), 0.0 ≤ y ≤ 0.8, are studied systemically using XRD, CO₂-TPD, SEM, EIS and I-V polarization characterizations. Zr doping suppresses carbonate formation, CO₂-TPD demonstrates that the formative rate of carbonate over BZCYy are 7.50 × 10^-6 and 8.70 × 10^-7 mol m^-2 min^-1 at y = 0.0 and 0.4, respectively. Investigation of sinterability shows that the anode-supported configuration helps the sintering of the thin-film electrolyte. Peak power densities of 220 and 84 mW cm^-2 are obtained at 750 and 450 °C, respectively, with BZCY0.4 electrolyte. Due to the favorable chemical stability against CO₂ and good sintering in the thin-film configuration, BZCY0.4 is a potential electrolyte material for H⁺-SOFCs.