Interface reactions in the NiO-SDC-LSGM system

The reactivity of NiO-SDC (samaria-doped ceria) anode material with a Sr- and Mg-doped lanthanum gallate (LSGM) electrolyte was studied by X-ray diffraction (XRD) and electrical measurements. It was found that a LaNiO3-based compound in hexagonal structure formed in binary powder mixtures of NiO and LSGM after firing at 1150 degreesC, Reaction between SDC and LSGM was also observed. Several SDC peaks merged with the adjacent LSGM peaks during firing, and a SrLaGa3O7 compound was identified as a reaction product. Reaction between LSGM and SDC could cause more than 50% loss in the ionic conductivity of LSGM-SDC electrolytes sintered at 1350 degreesC, The measured conductivity of an LSGM electrolyte with a NiO-LSGM anode prepared at 1350 degreesC was extremely low, indicating that the LaNiO3-based new phase is highly insulating. The reaction between NiO and SDC was not so obvious in comparison with NiO-LSGM and SDC-LSGM binary mixtures. (C) 2000 Elsevier Science B.V. All rights reserved.