Modulation of dual ion conductivity in composite electrolyte and its impact on the performance of single chamber solid oxide fuel cell

Designing dual oxideand proton-ion-conducting composite electrolytes with enhanced total ionic conductivity is essential for improving the performance of solid oxide fuel cells (SOFCs). Here, we report the impact of relative concentrations between proton and oxygen ion conducting electrolytes on the structure and electrical properties. Barium zirconate (BYZ) and samarium doped ceria (SDC) electrolytes prepared by combustion and co-precipitation method, respectively, were mixed in different ratios (0, 25, 50, 75, and 100 wt%) and sintered at 1400 degrees C for 6 h. X-ray diffraction studies indicate the co-existence of the perovskite and fluorite structures without the formation additional phases upon sintering. The electrochemical impedance spectra recorded under both reducing and oxidizing conditions demonstrate a reduction in grain boundary resistance of SDC with the increase in BYZ concentration. The composite with 75 % SDC and 25 % BYZ (S75B25) exhibits better conductivity in oxidizing and reducing environments with a maximum power density of 28 mW/cm(2) under single-chamber SOFC conditions. The analysis of Wagner polarization results indicates an ionic transport mechanism in S75B25. Our results demonstrate the significance of dual-ion conducting composite electrolytes on improving the performance of single-chamber SOFCs.