A benzoate coprecipitation route for synthesizing nanocrystalline GDC powder with lowered sintering temperature
| Autor: | Bahman Amini Horri, Robert C. T. Slade, Nasrin Ghaemi |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
010302 applied physics
Materials science Coprecipitation Process Chemistry and Technology Sintering 02 engineering and technology Electrolyte Conductivity 021001 nanoscience & nanotechnology 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Dielectric spectroscopy law.invention chemistry.chemical_compound chemistry law 0103 physical sciences Materials Chemistry Ceramics and Composites Calcination Ammonium benzoate 0210 nano-technology Thermal analysis Nuclear chemistry |
| Zdroj: | Ceramics International. 47:20009-20018 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2021.04.011 |
| Popis: | Electrolyte powders with low sintering temperature and high-ionic conductivity can considerably facilitate the fabrication and performance of solid oxide fuel cells (SOFCs). Gadolinia-doped ceria (GDC) is a promising electrolyte for developing intermediate- and low-temperature (IT and LT) SOFCs. However, the conventional sintering temperature for GDC is usually above 1200 °C unless additives are used. In this work, a nanocrystalline powder of GDC, (10 mol% Gd dopant, Gd0.1Ce0.9O1.95) with low-sintering temperature has been synthesized using ammonium benzoate as a novel, environmentally friendly and cost-effective precursor/precipitant. The synthesized benzoate powders (termed washed- and non-washed samples) were calcined at a relatively low temperature of 500 °C for 6 h. Physicochemical characteristics were determined using thermal analysis (TG/DTA), Raman spectroscopy, FT-IR, SEM/EDX, XRD, nitrogen absorptiometry, and dilatometry. Dilatometry showed that the newly synthesized GDC samples (washed and non-washed routes) start to shrink at temperatures of 500 and 600 °C (respectively), reaching their maximum sintering rate at 650 and 750 °C. Sintering of pelletized electrolyte substrates at the sintering onset temperature for commercial GDC powder (950 °C) for 6 h, showed densification of washed- and non-washed samples, obtaining 97.48 and 98.43% respectively, relative to theoretical density. The electrochemical impedance spectroscopy (EIS) analysis for the electrolyte pellets sintered at 950 °C showed a total electrical conductivity of 3.83 × 10−2 and 5.90 × 10−2 S cm−1 (under air atmosphere at 750 °C) for washed- and non-washed samples, respectively. This is the first report of a GDC synthesis, where a considerable improvement in sinterability and electrical conductivity of the product GDC is observed at 950 °C without additives addition. |
| Databáze: | OpenAIRE |
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