Stabilities and electrical conductivities of electrode materials for use in H2S-containing gases

Stabilities and conductivities of sulfides and lithiated sulfides derived from La0.9Sr0.1Ga0.8Cr0.2O3, LaCr0.9Ti0.1O3, Y0.9Ca0.1FeO3, and SrCo0.8Fe0.2O3 are studied in a gas mixture of 96% H-2 and 4% H2S at 900 degreesC using X-ray diffraction, microscopy, and impedance spectroscopy. Results indicate that the sulfide and lithiated sulfide derived from Yi(0.9)Ca(0.1)FeO(3) exhibit not only high stability but also high electrical conductivity, implying that they are viable candidate electrode materials for H2S polishing and for solid oxide fuel cells using H2S-containing fuels. In contrast, the lithiated sulfides derived from La0.9Sr0.1Ga0.8Cr0.2O3 and LaCr0.9 Ti0.1O3 exhibit relatively low electrical conductivity, although their chemical and thermal stability appeal. to be very good. On the other hand, the lithiated sulfides derived from SrCo0.8Fe0.2O3 show inadequate chemical stability under the testing conditions even though the electrical conductivity appears to be good.