Fabrication and optimization of La0.4Sr0.6Co0.2Fe0.7Nb0.1O3-δ electrode for symmetric solid oxide fuel cell with zirconia based electrolyte

La0.4Sr0.6Co0.2Fe0.7Nb0.1O3-δ (LSCFN) was applied as both anode and cathode for symmetrical solid oxide fuel cells (SSOFCs) with zirconia based electrolyte. The cell with LSCFN electrode was fabricated by tape-casting and screen printing. Fabrication process was optimized firstly by comparing co-sintering and separate-sintering of electrode and electrolyte. To further improve the LSCFN electrode properties, oxygen ionic conductor of Gd0.1Ce0.9O2-δ (GDC) was added into the LSCFN electrode. The preferred composition of LSCFN-GDC composite electrode was found to be 1:1 in weight ratio with polarization resistance of 0.16 Ω cm2 at 800 °C. The maximum power densities of LSCFN-GDC||GDC/YSZ/GDC||LSCFN-GDC tested in H2 and CH4 with 3% H2O were 395 mW cm−2 and 124 mW cm−2 at 850 °C, respectively, which were much higher than that of LSCFN||GDC/YSZ/GDC||LSCFN cells at same condition, possibly due to the extension of the triple phase boundary induced by the addition of GDC. The cell showed reasonable stability using H2 and CH4 with 3% H2O as fuels and no significant power output degradation was observed after total 200 h operation.