Dilatometer studies on LAMOX based electrolyte materials for solid oxide fuel cells

The present study deals with the citrate complexion synthesis of LAMOX-based Solid Oxide Fuel Cell (SOFC) electrolyte materials (La1.8Dy0.2Mo2-xWxO9 (x = 0, 0.1, 0.2, 0.5, and 1), La1.8Dy0.2Mo2-xGaxO9 (x = 0.1 and 0.2), and La1.8Dy0.2Mo2-xVxO9 (x = 0.025, 0.05, 0.1, and 0.2)) and their characterization to understand the sintering behaviour and phase stability. From the dilatometer studies, the linear shrinkage and shrinkage rate of the LDMW (x = 0, and 0.1) showed better shrinkage than LM and LDM. Gallium addition (LDMG) and Vanadium addition (LDMV) showed a negative impact on shrinkage behaviour. In the temperature range of 500-580 degrees C, the abrupt change in shrinkage rate showed the transition of phase from alpha to beta for the LM. The modification of LM to LDM, LDMW, and LDMV suppressed the formation of the alpha phase. During thermal expansion behaviour study in the temperature range of 100-500 degrees C and 550-800 degrees C, the LM sintered pellet showed the coefficient of thermal expansion (CTE) values of 13.3 x 10(-6)/degrees C and 21.6 x 10(-6)/degrees C respectively. The LDM and LDMW sintered pellets showed the CTE values in the range of 14-15 x 10-6/degrees C and 16-19 x 10-6/degrees C, respectively. The relative density of the sintered pellets (1100 degrees C/5 h in air) (LM, LDM, LDMW, and LDMG (x = 0.1)) is found to be >90%. It provides the suitability of these materials for further investigation as electrolytes of SOFCs/SOECs.