A STUDY ON THE LA1-XSRXMNO3 OXYGEN CATHODE

The impedance responses and current-overpotential characteristics were studied for oxygen reducing cathodes, stoichiometric La1-xSrxMnO3 (x = 0.16-0.20) in solid oxide fuel cells, under varying conditions of te mperature (700-900 degrees C) and oxygen partial pressure (1-10(-4) at m) for two distinctly different electrode morphologies (porous and den se structure). An electrode densified at the interface with the yttria -stabilized zirconia solid electrolyte was more efficient in this stud y. The reaction at the finely porous LSM proceeds via the triple phase boundary and ineffectively uses the mixed conductivity property of th e material. Reaction mechanisms for both cases (porous and dense struc ture) are discussed and compared with the literature. A new, two-layer ed cathode structure is proposed. Copyright (C) 1996 Elsevier Science Ltd.