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.