Enhanced electrochemical performance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ cathode by Zr4+, Sm3+ and Yb3+ tri-doped BaCeO3 compositing for intermediate-temperature thin-film fuel cells

Abstract

In this study, Zr4+, Sm3+ and Yb3+ tri-doped BaCeO3 (BaCe0.7Zr0.1Sm0.1Yb0.1O3-α) was prepared using a citric acid-EDTA combined complexing sol-gel method. The influence of sintering aid (CuO) content on structure, sinter-ability and conductivity of BaCe0.7Zr0.1Sm0.1Yb0.1O3-α (BCZSY) was studied using XRD, SEM and AC impedance. XRD patterns of different sintering aid contents and temperatures showed that all samples formed a pure BaCeO3 orthorhombic phase without any impurities. The conductivity of 1500-BCZSY reached 1.8×10-2 S.cm-1 and 1.9×10-2 S.cm-1 in dry nitrogen and hydrogen atmospheres at 700 °C, respectively. The anode-supported membrane fuel cells of NiO-BCZSY | BCZSY (13 μm) | Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and NiO-BCZSY | BCZSY (15 μm) | BCZSY-BSCF were fabricated, respectively. SEM results showed that the cathode, anode-support and electrolyte had good adhesion. The polarization resistance (Rp) of BCZSY-BSCF was significantly reduced by 34%, 44% and 55% compared to BSCF at 500 °C, 550 °C and 600 °C, respectively. The maximum power density (Pmax) using BCZSY-BSCF as the cathode increased by 18%, 17% and 22% compared to BSCF at 500 °C, 550 °C and 600 °C under the condition of slightly higher electrolyte film thickness, correspondingly.