Performance evaluation of microtubular solid oxide fuel cell prototypes at a laboratory scale and identification of requirements for gas sensors
2 Posgrado en Energía y Medio Ambiente; Universidad Autónoma Metropolitana Unidad Iztapalapa, Av. San Rafael Atlixco 186, Colonia Vicentina, Mexico City
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Solid Oxide Fuel Cells (SOFC´s) are devices for the chemical to electrical energies conversion. Traditional SOFC´s have been applied in stationary power generation systems based on their high efficiencies (~ 60%) and high operating temperatures (~ 1000 °C). They present the flexibility to be operated with a variety of fuels (e.g. hydrogen, alcohols, methane). Among the different architectures that they can present, microtubular SOFC´s have lower operating temperatures, higher tolerance to thermal cycles, faster start-up capacity and higher volumetric power densities, compared to conventional tubular SOFC´s. The present contribution includes results of the performance evaluation of microtubular SOFC´s. Prototypes were fabricated based on a dip coating technique; a cermet of Ni-Ce0.8Gd0.2O2-x was used as the anode, Ce0.8Gd0.2O2-x as the electrolyte, and La0.8Sr0.2Co0.2Fe0.8O3 as the cathode. The performance of the cells was evaluated based on the polarization curves obtained by linear sweep voltammetry measurements in the 500-600 °C range, using hydrogen as a fuel. Electrical Impedance Spectroscopy measurements were also performed. Failure of the cells can be predicted from electrical measurements and could be related to formation of fractures in the cells or the cement sealant. During the evaluation, safety relies on gas sensors to detect fuel leaks.