Performance of homogeneous and layered ceria/carbonate composite electrolytes

Multilayer ceramic and salt composite cells were prepared superimposing up to seven alternate layers of Ce0.9Gd0.1O1.95 (CGO) and mixtures of Na2CO3 (NC) and Li2CO3 (LC), with final sintering around 500 °C. Various other single component cells (CGO or NC + LC) and homogeneous composites (consisting of intimate mixtures of ceramics and salts) were prepared and used as reference. All these materials were characterized by X-ray diffraction, scanning electronic microscopy and impedance spectroscopy, in air.The layered cells electrical performance was studied both as series or parallel associations to try to inspect the specific electrical performance of the ceramic/salt interface. The multilayer cells resistance showed a close agreement with prediction based on classical series or parallel association models, and no sign of special contributions originated in the ceramic/salt interface. However, the electrode impedance appeared quite distinct for the various types of cells under analysis (single component, homogeneous and layered composites). This indeed suggests that interfaces play a role on the overall cell performance.

► Comparison of alkaline carbonates/ceramic composites as electrolytes.
► Manipulation and study of interfaces using layered composite cells.
► Investigation of the role of composite interfaces on ionic conductivity.
► Role of ceramic phase on electrode performance is evidenced.
► Solid/gas phase interactions influenced by the interfacial region.