DANIEL ZANETTI DE FLORIO
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Artigo IPEN-doc 23095 Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells2017 - NOBREGA, SHAYENNE D. da; MONTEIRO, NATALIA K.; TABUTI, FRANCISCO; FLORIO, DANIEL Z. de; FONSECA, FABIO C.Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium- doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs.Artigo IPEN-doc 23078 Proton and cesium conductivity in perfluorosulfonate ionomers at low and high relative humidity2017 - MATOS, BRUNO R.; SILVA, JAQUELINE S. da; SANTIAGO, ELISABETH I.; PARRA, DUCLERC F.; CARASTAN, DANILO J.; FLORIO, DANIEL Z. de; ANDRADA, HEBER E.; CARRERAS, ALEJO C.; FONSECA, FABIO C.Nafion exhibits one of the highest proton conductivity at room temperature and it is the standard electrolyte of proton exchange membrane fuel cells (PEMFC). However, the temperature dependence of ionic conductivity of Nation is highly dependent on the measuring conditions and it is still a matter of debate. In the present study, detailed dielectric spectroscopy (DS) measurements in both dry (under N2 flow) and water-saturated conditions were carried out in a broad range of temperature and frequency. Such DS results were correlated to differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) data taken in similar conditions. The main results revealed that in samples conditioned in N2 flow (RH ~0%) the transport of both proton and cesiumions is coordinated with the dynamics of Nafion relaxations. In hydrated Nafion (proton form), conductivity measurements at different frequencies revealed two regimes: one at high-frequency, in which the Vogel-Tamman- Fulcher (VTF) law indicates a close relation between the polymer glass transition temperature Tg; and, a second one at low frequency, bearing great similarity to the transport observed in nearly dry samples. The reported experimental results contribute to disentangle the intricate transport properties of Nafion.Artigo IPEN-doc 22866 Fabricação e testes de célula a combustível de óxido sólido suportada no anodo2006 - FLORIO, D.Z. de; FONSECA, F.C.; FRANÇA, Y.V.; BERTON, M.A.C.; GARCIA, C.M.; MUCCILLO, E.N.S.; MUCCILLO, R.A fabricação e os testes de células unitárias de óxido sólido suportadas no anodo são descritos. As células unitárias foram fabricadas por técnicas de baixo custo e foi dada ênfase ao uso de materiais disponíveis no Brasil. O projeto consistiu na preparação dos materiais componentes -anodo, eletrólito e catodo- e na construção de uma câmara porta-amostra estanque para medidas de propriedades eletroquímicas das células unitárias. Células cerâmicas suportadas no anodo do tipo: anodo (ZrO2:Y2O3 + NiO) / eletrólito (ZrO2:Y2O3) / catodo (La0.65Sr0.35MnO3 + ZrO2:Y2O3), foram preparadas pelo método de recobrimento de barbotina (slurry coating) e testadas entre 600º C e 800ºC após redução in situ do anodo. Os principais resultados mostram que o método de deposição resultou em célula unitária com boa reprodutibilidade e desempenho razoável, indicando que este método pode ser desenvolvido para fabricação de células de óxidos sólidos.Resumo IPEN-doc 22919 Preparação de compósitos cerâmicos para aplicação no ânodo de células a combustível de óxidos sólidos2016 - BEZERRA, MATHEUS E.O.; FLORIO, DANIEL Z. de; FONSECA, FABIO C.