Self-Assembled Triple (H+/O2-/e-) Conducting Nanocomposite of Ba-Co-Ce-Y-O into an Electrolyte for Semiconductor Ionic Fuel Cells

Triple (H+/O2-/e(-)) conducting oxides (TCOs) have been extensively investigated as the most promising cathode materials for solid oxide fuel cells (SOFCs) because of their excellent catalytic activity for oxygen reduction reaction (ORR) and fast proton transport. However, here we report a stable twin-perovskite nanocomposite Ba-Co-Ce-Y-O (BCCY) with triple conducting properties as a conducting accelerator in semiconductor ionic fuel cells (SIFCs) electrolytes. Self-assembled BCCY nanocomposite is prepared through a complexing sol-gel process. The composite consists of a cubic perovskite (Pm-3m) phase of BaCo0.9Ce0.01Y0.09O3-delta and a rhombohedral perovskite (R-3c) phase of BaCe0.78Y0.22O3-delta. A new semiconducting-ionic conducting composite electrolyte is prepared for SIFCs by the combination of BCCY and CeO2 (BCCY-CeO2). The fuel cell with the prepared electrolyte (400 mu m in thickness) can deliver a remarkable peak power density of 1140 mW center dot cm(-2) with a high open circuit voltage (OCV) of 1.15 V at 550 degrees C. The interface band energy alignment is employed to explain the suppression of electronic conduction in the electrolyte. The hybrid H+/O2- ions transport along the surfaces or grain boundaries is identified as a new way of ion conduction. The comprehensive analysis of the electrochemical properties indicates that BCCY can be applied in electrolyte, and has shown tremendous potential to improve ionic conductivity and electrochemical performance.

Automated summary

A stable twin-perovskite nanocomposite BCCY with triple conducting properties has been developed as a conducting accelerator in semiconductor ionic fuel cells (SIFCs) electrolytes. The BCCY-based composite electrolyte shows improved ionic conductivity and electrochemical performance in fuel cells, with a remarkable peak power density and high open circuit voltage at 550 degrees Celsius.