Characterization of Co-doped LSGM Electrolyte Prepared by GNP for IT-SOFC

Abstract

Co doping was used to enhance electrical conductivity of La0.8Sr0.2Ga0.8Mg0.2O2.8. The La0.8Sr0.2Ga0.8Mg0.2-xCoxO2.8 powders of two different compositions (x = 0.05 or 0.1) were synthesized using glycine nitrate process as the electrolyte material of intermediate temperature solid oxide fuel cells (IT-SOFCs). The electrical conductivity of La0.8Sr0.2Ga0.8Mg0.1Co0.1O2.8 at 800° is observed to be 0.145S/cm which is higher than that of La0.8Sr0.2Ga0.8Mg0.2O2.8 (0.127S/cm). And the linear thermal expansion coefficient was measured to be 15.2×10-6K−1 for La0.8Sr0.2Ga0.8Mg0.1Co0.1O2.8 which is very close to that of La0.6Sr0.4Co0.2Fe0.8O3-x (13.4×10-6K−1). The phase stability of La0.8Sr0.2Ga0.8Mg0.1Co0.1O2.8 in contact with La0.6Sr0.4Co0.2Fe0.8O3-x was fairly good. And the relative density values of La0.8Sr0.2Ga0.8Mg0.1Co0.1O2.8, when sintered at 1400° for 4 hours, were over 98%.