Effect of Microstructural Evolution on the Electrochemical Properties of High Performance SOFCs

Abstract

Microstructures of the component layers play a critical role in the performance of anode supported solid oxide fuel cells (SOFCs). Conventional SOFC configuration composed of laminated and cosintered NiO-YSZ (yttria stabilized zirconia) anode and YSZ electrolyte and screen printed YSZ-LSM (lanthanum-strontium manganite) was used to investigate the performance of the tailored microstructures. Identification of the polarization mechanisms in half and complete cells allowed improving the microstructural development of the electrodes. Polystyrene demonstrated striking features among the pore formers evaluated to optimize the microstructure of Ni-YSZ anodes. The effects of the composition and sintering temperature on the polarization of YSZ-LSM cathodes were investigated to optimize the cathode performance. The contribution of the electrolyte to the ohmic polarization was lowered by decreasing its thickness. Power densities over 1.75 W/cm 2 were measured at 800 o C in flowing 10% hydrogen -90% argon gas mixture on the anode side and air on the cathode side.

Effect of the anode microstructure on the enhanced performance of solid oxide fuel cells

“…Low electrical conductivity (157 S cm À1 ) of the anode of cell A gave rise to the ohmic loss and led to an increase in the total cell resistance. Further analysis of the impedance spectra showed that the previously developed cathode did not demonstrate any limitation in these cell configurations and both low and high frequency arcs are associated with the anode layer [54]. Deconvolution of the spectra also revealed that the high frequency arc (w10 kHz) corresponds to the anode activation processes which is in a good agreement with the studies reported in the literature [55e57].…”