Properties and performance of La_(1.6)Sr_(0.4)NiO_(4+δ)-Ce_(0.8)Sm_(0.2)O_(1.9) composite cathodes for intermediate temperature solid oxide fuel cells

摘要

La_(1.6)Sr_(0.4)NiO_(4+δ)-Ce_(0.8)Sm_(0.2)O_(1.9) composite cathodes were prepared successfully using combustion synthesis method for intermediate temperature solid oxide fuel cells. The chemical compatibility, thermal expansion behavior, electrical conductivity and electrode performance were studied. The X-ray diffraction of La_(1.6)Sr_(0.4)NiO_(4+δ)-Ce_(0.8)Sm_(0.2)O_(1.9) composite result proved a slight reaction between La_(1.6)Sr_(0.4)NiO_(4+δ) and Ce_(0.8)Sm_(0.2)O_(1.9). Both the thermal expansion coefficient and the electrical conductivity of La_(1.6)Sr_(0.4)NiO_(4+δ)-Ce_(0.8)Sm_(0.2)O_(1.9) decreased with increasing Ce_(0.8)Sm_(0.2)O_(1.9) content AC impedance spectroscopy measurements indicated that the addition of 30wt% Ce_(0.8)Sm_(0.2)O_(1.9) to La_(1.6)Sr_(0.4)NiO_(4+δ) exhibited the lowest polarization resistance (0.238 Ωcm~2) at 800 ℃ in air, which was only one fourth of the La_(1.6)Sr_(0.4)NiO_(4+δ) electrode measured at the same temperature.