Solid Oxide Fuel Cells with Symmetrical Pt-YSZ Electrodes Prepared by YSZ Infiltration

Abstract

Platinum electrodes for high temperature electrochemical devices (solid oxide fuel cells, solid oxide electrolyzer cells and sensors) generally show limited performances due to confinement of triple phase boundaries (TPBs) to the Platinum-electrolyte interface. Performance degradation as a result of TPB length loss due to the microstructural instability of the Platinum electrodes at operational temperatures is the other major problem. Infiltration of yttrium stabilized zirconia (YSZ) into porous Platinum electrodes using polymeric metal-oxide precursor was utilized as a prospective solution to these problems. It was shown that this process formed a YSZ coating on the Platinum particle surface which led to significantly increased effective contact area between Platinum electrodes and the electrolyte, and prevented the coarsening of Platinum. Symmetrical cells with YSZ infiltrated Platinum electrodes showed polarization resistance of 0.045 Ohm.cm2 per cathode at 800°C, in air. In fuel cell operation mode, the total electrode polarization resistance (anode + cathode) was 0.35 Ohm.cm2 at 800°C and 0.130 Ohm.cm2 at 900°C. Power densities of 0.45 Watt/cm2 and 0.9 Watt/cm2 at 800°C and 900°C were obtained respectively. No degradation of the cell was observed for the duration of measurement (248 hours).