Preprint article · Journal article
Gd0.2Ce0.8O1.9/Y0.16Zr0.84O1.92 nanocomposite thin films for low temperature ionic conductivity
Gd0.2Ce0.8O1.9/Y0.16Zr0.84O1.92 (GDC/YSZ) nanocomposite is synthesized by a novel hybrid chemical route, where colloidal crystalline GDC nanoparticles from continuous hydrothermal synthesis are dispersed into a metalorganic YSZ matrix precursor. The result is a mixture of metal oxides in which GDC nanoparticles are finely distributed in a continuous metalorganic polymeric matrix to be crystallized after calcination.
The GDC nanoparticles reduce the temperature necessary to obtain crystalline YSZ, which is already formed at 400 °C. The nanocomposite reveals structural stability up to 800 °C when treated in both air and reducing atmosphere, showing the onset of diffusion below 1000 °C. The diffusional processes are largely dependent on the nanometric grain size, with Zr4+ diffusing abruptly towards GDC in air at 1000 °C and GDC/YSZ interdiffusion being hindered in reducing environment despite the onset temperature of 900 °C.
The nanocomposite precursor is an inkjet-printable reactive water-based material, suitable for the deposition of thin films with a thickness below 100 nm after calcination at 750 °C. The crystal structure of the film reveals no interaction between GDC and YSZ but a microstrain (0.3% tensile strain for YSZ).
The thin film microstructure shows a compact layer with 94% density. The nanocomposite shows high oxygen ionic conductivity at low temperatures (>5⋅10-3 S⋅cm-1 at 500 °C), low activation energy (0.55 eV), and dominant oxygen ionic conductivity even in reducing conditions (pO2 <10–25 atm). We show that these properties arise from the large interface between the components of the composite, due to the embedding of the GDC nanoparticles in the YSZ matrix, while ZrO-CeO intermixing can be avoided and no n-type conductivity is observed even at low oxygen activities and high temperatures.
Language: | English |
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Year: | 2019 |
Pages: | 162-171 |
ISSN: | 00223697 and 18792553 |
Types: | Preprint article and Journal article |
DOI: | 10.1016/j.jpcs.2019.04.019 |
ORCIDs: | Gadea, Christophe , Xu, Yu , Kiebach, Ragnar , Esposito, Vincenzo and 0000-0002-6899-6348 |
Gadolinium doped ceria Ionic conductivity Nanocomposite Thin film Yttrium-stabilized zirconia