Lanthanum manganite LaMnO

In addition to noble metals, conducting perovskite family oxides are the preferred cathode materials. Lanthanum manganite (LaMnOs), which, when substituted with low valence elements, such as Ca or Sr, has a superior p-type electronic conduction due to the formation of large amount of Mn" ". Moreover, doped LaMnOa possesses adequate electrocatalytic activity for oxygen reduction, a reasonable thermal expansion match to YSZ, and stability in the SOFC cathode operating environment. Under the cathode operation conditions, doped LaMnOa has oxygen excess, or precisely speaking, has cation vacancies, and the oxide ion conductivity is relatively low in Sr doped LaMnOa (LSM), of the order of 10 S/ cm at 800 °C. 

The first peak of the lanthanum manganite sample bulk reduction at 350 °C (Fig. 38) corresponds to reduction of Mn" cations into Mn state without destruction of perovskite lattice. The second TPR peak corresponds to the LaMnOs perovskite reduction into a mixture... 

Perovskite-type Sr-doped LaMnOs (Lanthanum Strontimn Manganites- LSM) has particularly attracted substantial interest as a promising material for cathode in SOFCs. This material has good properties such as chemical and thermal stability, and high catalytic activity for oxygen reduction. Additionally, it has a thermal expansion coefficient similar to that of a solid electrolyte (YSZ), and high electronic conductivity [2]. 

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