SI Longtao, LI Kang, WANG Zi’an, SUN Keqiang, GE Lin, YAO Yufan, WANG Yu
(College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China)

Abstract: BaCo_0.4Fe_0.4Zr_0.1Y_0.1O_3−δ (BCFZY) is a new type of triple-conductive cathode material with proton-oxygen ion-electron conduction for proton ceramic fuel cells (PCFC), with excellent electrocatalytic activity in low and intermediate temperature range (500–700 ℃). However, the thermal expansion coefficient of BCFZY is much larger than that of electrolytes, which seriously hindered the electrode performance in PCFC. In this study, BCFZY was introduced into BaZr_0.85Y_0.15O_3−δ  porous backbone using a precursor solution infiltration method to prepare composite cathode, with thermal expansion mismatch was effectively alleviated, so that the electrochemical performance was obviously improved. The optimum infiltrating concentration is ~46.7 wt.% and the polarization resistance of the optimized electrode is 0.20 Ω·cm² at 600 ℃, which is about 63% lower than that of the BCFZY electrode prepared by using screen-printing method. The relaxation time (DRT) distribution method was used to analyze electrochemical processes of the electrode, suggesting that the improved performance of the BCFZY electrode is mainly related to the acceleration of the charge transfer, the ion formation and the gas diffusion processes.
Key words: proton ceramic fuel cells; infiltrate; triple-conducting; electrochemical performance