LI Zhaoqiang ^{1, 2,} PAN Zhaoxu ¹, WANG Zhenwei ¹, SUN Haibin ¹
(1. School of materials science and engineering, Shandong University of Technology, Zibo 255000, Shandong, China; 2. Non-Commissioned Officer Department, Binzhou Polytechnic, Binzhou 256600, Shandong, China)

Abstract: In order to improve the catalytic activity of La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF)-Er_0.4Bi _1.6O₃(ESB) composite cathodes during the oxygen reduction process, electroless silver plating method was applied for surface modification, thus obtaining LSCF-ESB-Ag cathodes. The introduction of Ag significantly reduced the polarization impedance, reaching the lowest value (0.03 Ω·cm² at 700 ℃) at the Ag loading of 15 wt.%, which is only 27% of that of the LSCF-ESB composite cathode (0.11 Ω·cm² at 700 ℃). According to the cathodic reaction kinetics, the modification of Ag increased the speed of oxygen surface adsorption, dissociation and charge transfer. The NiO-SDC/SDC/LSCF-ESB-Ag single cell exhibited a peak power density of 535 mW·cm⁻² at 700 ℃, when using wet hydrogen as the fuel.
Key words: solid oxide fuel cell; electroless silver plating; surface modification