Preparation of YSZ Thin Film byElectrophoretic Deposition Method

• Main Authors: Dee-Way Yang, 楊帝威
• Other Authors: Kuan-Zong Fung
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/69308236745602796140

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 94 === Due to its efficiency, and potentially low cost, solid oxide fuel cells (SOFCs) have been one of the most important energy devices for power generation. Traditionally, it’s common to apply the thick yittria-stablized zirconia (YSZ) solid state electrolyte (about 750 μm) as the support of the cells and follow by the deposition of thin layers as the anode and cathode. The working temperature of the cell using thick electrolyte SOFCs is at about 900~1000℃ in order to obtain the higher ion conductivity. But the high working temperature would limit the limitations of the materials used for SOFCs, due to the sintering of high surface area electrodes, the interaction between electrode and electrolyte, In order to reduce the operating temperature of SOFCs, two methods may used to solve the problem: 1. Developing the electrolyte material with higher ion conductivity, to replace YSZ. 2. Reducing the ohmic resistance using thin-film electrolyte. In this study, the electrophoretic deposition (EPD) was adopted to fabricate the thin-film the electrolyte of the SOFCs. The EPD is a simple process, with low cost, few limitations of the shape, and is suitable for mass-production. In this study, the success of EPD process is highly dependent on the stability of colloidal suspension. Therefore the iodine was added to enhance the conductivity and zeta potential of suspension. Then the applied voltage and current on the morphology of deposited YSZ thin film were examined by SEM. The electrically conducting anode was used as the substrate, depositing YSZ electrolyte thin film layer. About 30 μm YSZ electrolyte was deposited on anode substrate by EPD. Following by sintering at 1400℃ for 2 hours, then, the cathode layer was applied by screen printing upon the dense electrolyte. After a single cell was assembled the polarization rests were conducted at 600, 700, 800℃. The resulting power density is 0.21, 0.65, 1.12 W/cm2, respectively. Such a high power density indicates that EPD process is a feasible and cost-effective method for the fabrication of electrode-supported thin film SOFCs.