LAUSR

Abstract Herein, the spinel oxide CuBi2O4 is prepared by solid-state reaction method and characterized for the first time as a cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). CuBi2O4 (CBO) crystallizes in tetragonal structure and is chemically compatible with Ce0.9Gd0.1O1.9 (GDC) electrolyte at 800 °C. Electrical conductivity relaxation is conducted to assess the oxygen surface exchange coefficient kchem and oxygen bulk diffusion coefficient Dchem of CBO material. It is found that CBO exhibits better oxygen transport properties than the traditional La0.8Sr0.2MnO3 (LSM) and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes. The electrochemical activity of CBO-based cathode is investigated by impedance spectroscopy on the symmetric cell with GDC electrolyte. The CBO cathode forms good contact with the GDC electrolyte and displays low polarization resistance (RP) values, e.g., 0.58 Ωcm2 at 700 °C in air. The introducing GDC to form a composite cathode with CBO further reduces the RP to 0.39 Ωcm2. An anode-supported single cell with the CBO-GDC cathode exhibits a peak power density of 507 mWcm−2 at 750 °C, suggesting the viability of CBO oxide as a cathode material for IT-SOFC.