Effect of O2 concentration on performance of solid oxide fuel cells with V2O5 or Cu added (LaSr)(CoFe)O3–(Ce,Gd)O2−x cathode with and without NO

A solid oxide fuel cell unit is constructed with Ni-(Ce,Gd)O2−x (GDC) as the anode, yttria-stabilized zirconia as the electrolyte, and V2O5 or Cu added (LaSr)(CoFe)O3–GDC as the cathode. The effect of the O2 concentration on the open circuit voltage (OCV) is studied and a mass-transfer limited OCV is observed. The power density with Cu addition can be much higher than that with V2O5 addition but the effect of the O2 concentration with Cu addition is larger than that with V2O5 addition. Without the presence of NO, both the power density and the OCV decrease with decreasing O2 concentration. The OCV variation can be substantial with the variation of the flow rate, the O2 concentration and the NO concentration. The presence of CO2 can increase the OCV while that of NO can decrease the OCV; however, a synergistic effect can occur on the OCV when NO is present at a very low O2 concentration which results in a sudden drop of the OCV.