| In this work, the technique of electrophoretic deposition (EPD) was investigated for the fabrication of thin-layer electrolytes for intermediate-temperature solid oxide fuel cell applications. Extensive screening tests were conducted to determine the most suitable suspension for EPD, and it was found that an ethanol-based suspension containing 10 g/L YSZ electrolyte, 3.0 g/L Surfonic PE1198 dispersant, and 1.5 g/L PVB binder maximised area-specific deposit mass per deposition time. Scanning electron microscopy analysis of the sintered YSZ films indicated that dense, crack-, and pore-free electrolyte layers as thin as 4 mum could be generated that were sufficiently thin to surpass the area-specific resistance metric of B.C.H. Steele (ASR ≤ 15 O·cm 2) at an operating temperature of 700°C. A study of the kinetics of EPD was conducted to develop a simple model of deposition, such that the thickness of the electrolyte layer could be predicted as a function of the deposition time. It was found, however, that the electrolyte thickness was dependent on the resistance of the anode, which varied with the presintering temperature of the anode, and was not accounted for in the kinetic model. Open circuit voltage measurements were used to determine the functionality of the electrolyte layer, and the observed voltage of 0.98 V agreed well with the theoretical value of 1.13 V at an operating temperature of 875°C.; The phenomenon of curvature of the anode/electrolyte half-cells was also investigated. The effect of the anode presintering temperature, between 700 and 1200°C, and the sintering dwell time on half-cell curvature were investigated. It was found that the sintering dwell time had little effect on the curvature. On the other hand, the anode presintering temperature had a marked effect on the anode quality (surface composition and electrical conductivity), which affected the electrolyte deposit thickness, and subsequently the curvature. Presinter temperatures of 700 and 1200°C resulted in the minimum amount of curvature. |
