American Chemical Society
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Fe-Doped Ba0.9K0.1FexCo1–xO3−δ Perovskite Cathode Material for Low-Temperature Solid Oxide Fuel Cells

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journal contribution
posted on 2023-06-19, 07:03 authored by Jiamei Liu, Yifu Jing, Decai Zhu, Yingbo Zhang, Xinfang Li, Xin Jia, Yuzhao Ouyang, Xiaowei Gao, Hongmei Luan, Ze Li, Chengjun Zhu
This study systematically investigated the effects of a single B-site dopant (Fe, x = 0–1.0) on the structure and oxygen reduction reaction of the Ba0.9K0.1CoO3−δ (BKC) material used as a cathode for low-temperature solid oxide fuel cells (LT-SOFCs). The structural, electronic, and electrocatalytic properties of the cathode materials prepared by a sol–gel method were comparatively characterized. The results indicated that cubic perovskite structure BKFxC (Fe, x = 0.5, 0.6) materials had been formed by calcination at 900 °C for 5 h. Moreover, in order to examine the electrochemical properties of BKFxC, the BKFxC cathode was constructed on the Sm0.075Nd0.075Ce0.85O2−δ (SNDC) electrolyte (BKFC/SNDC/BKFC: denoted as symmetric cells); the lowest polarization resistance (RP) was obtained for the BKF0.5C symmetric cell (1.6 Ω·cm2 at 550 °C), which demonstrated much higher electrocatalytic activity than that of a similar cell with the BKF0.6C cathode (2.87 Ω·cm2 at 550 °C). A single cell with the BKF0.5C cathode achieved a top power density of 752 mW·cm–2 at 550 °C, which is 0.35 times higher than that of the single cell with the BKF0.6C cathode (power density: 556 mW·cm–2). The corresponding total interface RP of the fuel cell was 0.303 Ω·cm2, lower than that of the doping amount of 0.6 (550 °C, 0.402 Ω·cm2). Meanwhile, O2 temperature-programmed desorption (O2-TPD) and thermogravimetric (TG) analysis were used to characterize the valence of Fe and Co changing from +4 to +3 as well as the stable structure of the material from room temperature to 600/1000 °C. As a result, a highly efficient method for the innovative BKFC cathode was developed in this work.