Ag Doped LaMnO₃ As a Novel Cathode Material for SOFC Using YSZ Electrolyte

In this work, Ag doped LaMnO3 oxide (La1-xAgxMnO3-d) was synthesized by sol-gel method and the characteristics such as the phase stability, compatibility against YSZ electrolyte, the electronic state of Mn, electrical conductivity and power generation property when used as a cathode of SOFC were investigated. The solubility limit of Ag into LaMnO3 perovskite structure was about 10% (La0.9Ag0.1MnO3-d, LAM01), and the clear reactive phase was not confirmed when LAM01 was mixed with YSZ electrolyte and sintered at 975oC for 100h. The electronic state of Mn was almost same as that of La0.9Sr0.1MnO3-d(LSM01) at room temperature. The main charge carrier of LAM01 was electron hole (h+) and its electrical conductivity was higher than that of LSM01.The power generation property of the SOFC cell using LAM01 cathode showed the similar performance of that of LSM01 cell. In addition, the deposition of Ag metal was not clearly confirmed by the various observation after the power generation test, suggesting that the excellent property of LAM was not caused by the extrusion of Ag nano catalyst from LAM oxide. This work also suggests that the material design of SOFC cell without cathode interlayer is possible by using the dopant such as Ag, which has less reactivity against YSZ electrolyte.