Solid State Ionics, Vol.181, No.29-30, 1366-1371, 2010
Preparation and evaluation of new composites as anodes for intermediate-temperature solid oxide fuel cells
Composites, which consist of Sr-doped LaCrO3, CeO2, and NiO, were prepared according to a general formula (La0.7Sr0.3)(1-x)CexCr1-xNixO3-delta (x = 0-0.6) and were assessed as anodes for intermediate-temperature solid oxide fuel cells (ITSOFCs) in terms of phase structure, electrical conductivity, thermal expansion coefficient, and fuel cell performance. Results showed, for x>0.2, CeO2 and NiO precipitated after being calcined at 800-1450 degrees C and dispersed on a doped LaCrO3 support. At 800 degrees C, the electrical conductivities of the composites (for x = 0.2, 0.4 and 0.6) in a humidified 3% H2O hydrogen atmosphere were 0.72, 1.22 and 4.89 Scm(-1), respectively. The average values of the thermal expansion coefficients of the composites (in a temperature range of 30-800 degrees C) were 11 x 10(-6) (x = 0.2) and 11.5 x 10(-6) K-1 (x = 0.6). SOFCs with different anodes were characterized by current-voltage measurements and electrochemical impedance spectroscopy. The peak power density of a single cell with different composite anodes increased with increasing x. At 800 degrees C, the maximum power density was 81.5 mW cm(-2), and the area specific resistances of the single cells under open circuit condition were 3.1 (x = 0.2) and 1.6 Omega cm(-2) (x = 0.6) using humidified (3% H2O) hydrogen as fuel and ambient air as oxidant. (C) 2010 Elsevier B.V. All rights reserved.