화학공학소재연구정보센터
Journal of Power Sources, Vol.413, 334-343, 2019
Impact of silicate substrate and cosintering on cathode performance in an inert substrate-supported solid oxide fuel cell
In this study, cathode performance of cost-effective inert substrate-supported solid oxide fuel cells fabricated by a single step cosintering process is investigated. The polarization resistance of cosintered inert substrate-supported cathode symmetrical cells (ISC) is compared with the polarization resistance of electrolyte-supported symmetrical cells (ESC) prepared by post- and cosintering. ESC prepared by cosintering have similar polarization resistance than ESC prepared by post-firing due to the addition of pore formers. However, the implementation of a porous inert substrate increases the polarization resistance. Analysis of electrochemical impedance spectra could exclude a gas-phase diffusion limitation due to the porous substrate. Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) reveals an accumulation of zinc, magnesium and silicon on the inner pore surface of the cathode layer. Thermodynamic calculations confirm desorption of these elements from the silicate substrate during the cosintering. In addition, a zinc manganite spinel is detected in the cathode layer via confocal Raman spectroscopy, which indicates a reaction between the cathode material and zinc. The larger cathode polarization resistance of the inert substrate-supported cell is attributed to microstructural changes and the coverage of the cathode surface.