Synthesis and characterization of Ca doped LaMnO3 as potential anode material for solid oxide electrolysis cells

There is a need for investigating new electrode materials for solid oxide electrolysis cells (SOEC) as conventional electrodes for solid oxide fuel cells (SOFC) have some limitations when they are used in SOEC mode. Sr substituted LaMnO3 (LSM) is reported to have some demerits when it is used as an anode material in SOEC. With the intention of finding new anode material for SOEC, a series of materials, where Sr of LSM was either partially or fully substituted by Ca, were synthesized via combustion synthesis method. The synthesized material was found to be phase pure with orthorhombic symmetry. Thermal expansion coefficients (TEC) of all the samples were found to be in the range of 11-12x10(-6) K-1. Electrical conductivity was found to increase with increasing Ca-content for the samples where Sr was fully replaced by Ca (LCM) but the same was found to decrease with increasing Ca-content for the partially Sr substituted samples (LSCM). The materials with either partial or total substitution of Sr by Ca were used as an anode material of a coupon cell and tested in SOEC mode. These anode materials were found to be better than LSM in terms of hydrogen production. Also, LCM and YSZ did not react with each other even after a prolonged annealing of 100 h at 1000 degrees C.