La1-xSrxMnO3-delta, La1-xSrxCo1-yFeyO3-delta and Ba1-xSrxCo1-yFeyO3-delta: the Huey, Dewey and Louie of Solid Oxide Fuel Cell cathode materials

Perovskite materials are widely studied as cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFC) for their relevant properties regarding electrocatalytic activity or stability. Nevertheless, a material that combines both it is not yet available. Among them, La1-XSrxMnO3 (LSM), La1-xSrxCo1-yFeyO3 (LSCF), Ba1- xSrxCo1-yFeyO3 (BSCF) were deeply investigated but their properties are not completely exploited or optimized [1]. Here results about these materials are presented to show new possible routes to employ them. All the reported electrode materials are investigated using different approaches, such as infiltration and composite electrodes. The study starts from LSM - based electrodes, which show a change in kinetic mechanism under particular operating conditions. These results open new horizons about the employment of this material, up today considered not suitable for IT-SOFC temperature range. A first application, with promising results, is proposed here with a LSM infiltration in LSCF and BSCF scaffold [2]. Fig. 1a shows the decreasing in degradation rate in LSM-infiltrated BSCF electrode compared with reference one. The presence of infiltrated-phase enhance stability and electrochemical activity of electrodes. Further promising results are obtained also by mixing BSCF and LSCF powders. Three different BSCF:LSCF ratio are considered to produce three different cathodes [3]. All the new compositions show an improvement of activity for oxygen reduction reaction, with very competitive values of polarization resistance (Fig. 1b). Moreover, one of these new electrodes has also a lowering of degradation rate compared with reference materials.