Electrochemical performance of silver-modified Ba0.5Sr0.3Co0.8Fe0.2O3-delta (BSCF-Ag) as oxygen reduction electrodes for a protonic intermediate-temperature solid-oxide fuel cell (SOFC-H+) with BaZr0.1Ce0.8Y0.1O3 (BZCY) electrolyte was investigated. The BSCF-Ag electrodes were prepared by impregnating the porous BSCF electrode with AgNO3 solution followed by reducing with hydrazine and then firing at 850 degrees C for 1 h. The 3 wt.% silver-modified BSCF (BSCF-3Ag) electrode showed an area specific resistance of 0.25 Omega cm(2) at 650 degrees C in dry air, compared to around 0.55 Omega cm(2) for a pure BSCF electrode. The activation energy was also reduced from 119 kJ mol(-1) for BSCF to only 84 kJ mol(-1) for BSCF-3Ag. Anode-supported SOFC-H+ with a BZCY electrolyte and a BSCF-3Ag cathode was fabricated. Peak power density up to 595 mW cm(-2) was achieved at 750 degrees C for a cell with 35 mu m thick electrolyte operating on hydrogen fuel, higher than around 485 mW cm(-2) for a similar cell with BSCF cathode. However, at reduced temperatures, water had a negative effect on the oxygen reduction over BSCF-Ag electrode, as a result, a worse cell performance was observed for the cell with BSCF-3Ag electrode than that with pure BSCF electrode at 600 degrees C. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.