Elemental Diffusion between Sm0.5Sr0.5CoO3-delta Cathode and La0.9Sr0.1Ga0.8Mg0.2O3-delta Electrolyte

The effect of elemental diffusion from strontium-doped samarium cobaltite (SSC) cathode to lanthanum strontium magnesium gallium oxide (LSGM) electrolyte was investigated by electrochemical impedance spectroscopy (EIS) combined with X-ray diffraction (XRD). The XRD results showed that LaSrGa3O7 and LaSrGaO4 appeared at the interface between LSGM and SSC after sintering at high temperature. When the sintering temperature reached 1373 K, the high electronic conduction of the La-Sr-Co-O compound was formed. The decrease of open-circuit voltage and oxygen ion transfer number, and the increase of electronic conduction of LSGM electrolyte are the results of the cobalt diffusion from electrode to the LSGM film. The EIS results indicate that the electronic conduction of LSGM increases and the oxygen ion transfer number and open-circuit voltage decrease with increasing cathode sintering temperature, which arc caused by the formation of LaSrGa3O7 and LaSrGaO4 at the interface of LSGM and SSC.