Proton conducting Zn-doped BaZr0.1Ce0.7Y0.1Zn0.1O3−δ electrolyte with enhanced ionic conductivity for durable CH4 fueled solid oxide fuel cells

BaCeO 3 -based proton conductors exhibit high ionic conductivity but suffer from poor chemical stability and high sintering temperatures, limiting their application in protonic ceramic fuel cells (PCFCs). This study demonstrates that Zn doping in BaZr 0.1 Ce 0.7 Y 0.2 O 3−δ (BZCY) enhances both chemical stability and ionic conductivity. BaZr 0.1 Ce 0.7 Y 0.1 Zn 0.1 O 3−δ (BZCYZn) achieves higher proton conductivities of 0.022 S cm −1 in humid H 2 and 0.019 S cm −1 in CH 4 at 750 °C, surpassing those of BZCY. Zn doping improves conductivity in both the bulk and grain boundaries. An anode-supported single cell using BZCYZn as the electrolyte delivers peak power densities of 1324.63 mW cm −2 in H 2 and 647.49 mW cm −2 in CH 4 , significantly outperforming BZCY. The electrochemical performance and mass transport properties of BZCYZn are further analyzed using distribution of relaxation times (DRT) analysis.