Study of Ga Doped LSCM as an Anode for SOFC

Abstract

A phase pure La0.75Sr0.25Cr0.4Ga0.1Mn0.5O3 (LSCGM) was synthesized by the solid state reaction method. LSCGM crystallized with rhombohedral symmetry in the space group R-3c. AC impedance measurements using symmetrical cell arrangement showed that the area specific resistance (ASR) was 0.69 W cm2 at 850°C in wet 5%H2. A three-electrode arrangement with thick electrolyte was used to study the anodic characterization in isolation at various temperatures in wet hydrogen (97 vol% H2 and 3vol% H2O) and methane (97 vol% CH4 and 3 vol% H2O) over a period of 100 hr. For H2, the open circuit voltage (OCV) was found to decrease with temperature, whereas a different trend was observed in CH4. The value of anodic polarization (RP) at ~868OC was found to be 0.65 Ωcm2 and 2.0 Ωcm2 in wet hydrogen and methane respectively. At 900OC, the corresponding values were 0.45 and 1.65 Ωcm2 respectively. The microstructural study revealed a good LSCMG - YSZ interface even after 100 hr of operation.