Banca de QUALIFICAÇÃO: GRAZIELE LOPES DE SOUZA
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.DISCENTE : GRAZIELE LOPES DE SOUZA
DATA : 21/12/2016
HORA: 10:00
LOCAL: Sala de Aula PPGCEM
TÍTULO:
Synthesis of alternative oxides for solid oxide fuel cells of intermediate temperature
PALAVRAS-CHAVES:
- Electrolyte, cathode, lanthanum silicate, lanthanum nickelate, solid oxide fuel cell.
PÁGINAS: 63
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
RESUMO:
This work reports the synthesis of lanthanum silicate powders of composition La10Si6O27 and lanthanum nickelate (La2NiO4) to be used as electrolyte and cathode materials, respectively, in solid oxide fuel cells. The lanthanum silicate was obtained from a novel chemical route combining sol-gel and co-precipitation methods. The synthetic procedure proposed in this paper to obtain the electrolyte material is advantageous in reducing the power consumption and processing time, key elements to reduce the total manufacturing cost. As-prepared lanthanum silicate powders were calcined between 500 and 900 °C and characterized by X-ray diffraction with Rietveld refinement of the diffraction data, and scanning electron microscopy. The structural characterization indicated the formation of single-phase material after calcination at 900 ° C. The effect of sintering temperature, varied between 1400 to 1450 ° C, on the electrical properties were investigated by impedance spectroscopy between 400 and 800 ° C in air atmosphere. The lanthanum silicate electrolyte sintered at 1450 showed total electrical conductivity of 2.12x10-3 S.cm-1 at 700 ° C, in line with literature values for samples sintered at 1500 °C. The lanthanum nickelate was prepared by the method citrate and calcined at 1250 °C. The electrochemical performance as a cathode material was evaluated in a symmetric cell configuration (cathode/substrate/cathode) using the impedance spectroscopy technique. Cathodes of lanthanum nickelate obtained by screen printing and sintered at 1300 ° C for 4 h exhibited an area specific resistance (ASR) of 2.85 ohm.cm2 at 800 °C in oxygen atmosphere.
MEMBROS DA BANCA:
Interno - 1298936 - ANTONIO EDUARDO MARTINELLI
Interno - 1300987 - CARLOS ALBERTO PASKOCIMAS
Presidente - 1350249 - RUBENS MARIBONDO DO NASCIMENTO