Abstract
Herein, the spinel oxide CuBi 2 O 4 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). CuBi 2 O 4 (CBO) crystallizes in tetragonal structure and is chemically compatible with Ce 0.9 Gd 0.1 O 1.9 (GDC) electrolyte at 800 °C. Electrical conductivity relaxation is conducted to assess the oxygen surface exchange coefficient k chem and oxygen bulk diffusion coefficient D chem of CBO material. It is found that CBO exhibits better oxygen transport properties than the traditional La 0.8 Sr 0.2 MnO 3 (LSM) and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-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 ( R P ) values, e.g., 0.58 Ωcm 2 at 700 °C in air. The introducing GDC to form a composite cathode with CBO further reduces the R P to 0.39 Ωcm 2 . 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. • CuBi2O4 exhibits fast surface oxygen exchange and bulk diffusion properties. • CuBi2O4 forms good contact with GDC electrolyte at low sintering temperatures. • CuBi2O4 cathode shows improved electrochemical performance below 700 °C.
Published Version
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