Citrate–hydrothermal synthesis, structure and electrochemical performance of La0.6Sr0.4Co0.2Fe0.8O3−δ cathodes for IT-SOFCs

• Autor(a) principal: Garcia, Laurênia Martins Pereira
• Data de Publicação: 2013
• Outros Autores: Macedo, Daniel Araújo de, Souza, Graziele L., Motta, Fabiana Villela da, Paskocimas, Carlos Alberto, Nascimento, Rubens Maribondo do
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/45596; http://dx.doi.org/10.1016/j.ceramint.2013.04.019
• topic: Citrate–hydrothermal method; LSCF; Microstructure; Praseodymium oxide; Impedance spectroscopy

La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) powders were synthesized by a combination of citrate and hydrothermal methods. The thermal decomposition behavior of the as-prepared powder was carried out by simultaneous thermogravimetry–differential thermal analysis. The calcined powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size distribution (PSD). Screen-printed LSCF/CGO/LSCF symmetrical cells were sintered between 1150 and 1200 °C and studied by impedance spectroscopy in order to assess the cathode kinetics for the oxygen reduction reaction. Rietveld refinement of XRD data showed the formation of a single perovskite LSCF phase with crystallite size of 53 nm at 900 °C. The best area specific resistance (ASR) value, measured in static air, was found to be 0.34 Ω cm2 at 750 °C, demonstrating that the novel citrate–hydrothermal method is an effective way to prepare cathode materials for SOFC. Cathode performance can be further enhanced by additional surface modification through impregnation with Pr-containing solution, reaching 0.17 Ω cm2 at 750 °C. Furthermore, the activation energy of the PrOx-impregnated cathode is 83.4 kJ/mol, i.e., much lower than 123.8 kJ/mol, the best value determined for PrOx-free cathodes