La[sub 0.8]Sr[sub 0.2]Cr[sub 0.98]V[sub 0.02]O[sub 3−δ]Ce[sub 0.9]Gd[sub 0.1]O[sub 1.95]–Ni Anodes for Solid Oxide Fuel Cells

Solid oxide fuel cells ͑SOFCs͒ were fabricated with thick Ce 0.9 Gd 0.1 O 1.95 ͑GDC͒ electrolytes, composite anodes containing La 0.8 Sr 0.2 Cr 0.98 V 0.02 O 3-␦ ͑LSCV͒, GDC, and NiO, and Au current collector grids.SOFCs with varying anode firing temperatures, GDC contents, and NiO contents were structurally evaluated and characterized by current-voltage measurements and electrochemical impedance spectroscopy in humidified hydrogen and air.With increasing anode firing temperature, particle sizes in the porous anodes increased and the area specific resistance ͑R AS ͒ increased ͑power density decreased͒.For lower firing temperatures, e.g., 1100°C, R AS decreased sharply with increasing NiO content from 0 to 5 wt %, but showed little further decrease from 5 to 20 wt % NiO.R AS values were generally higher for higher firing temperatures, e.g., 1400°C, decreasing gradually with increasing NiO content from 0 to 20 wt %.These trends were explained by an increase in Ni particle sizes with increasing firing temperature, making the Ni catalyst less effective.The anode polarization resistance at 750°C was ϳ0.8 ⍀ cm 2 at 450 mV cell voltage ͑0.1 ⍀ cm 2 at open circuit͒, for a composition of 47.5 wt % LSCV, 47.5 wt % GDC, and 5 wt % NiO.