Preparation Of Zirconia Film With Low Cost And Their Application In Fuel Cells

Solid oxide fuel cells (SOFCs) are solid-state electrochemical device that convert the chemical energy of reaction directly into electrical energy. It possesses several distinct advantages, such as environmental friendship, higher conversion efficiency and broad adaptive fuels, which is a new green energy developed in the world for 21 century. In SOFCs, the polarization of anode and cathode parts is smaller, and the loss of the polarization mainly is due to the ohm loss of electrolyte. In order to enhance the current density and output power density, it is essential to reduce the thickness of the electrolytes. One of the effective ways for lowing internal resistance of cell is that the electrolyte is fabricated into membranes in structure. Therefore, some membrane-forming technologies have been developed to prepare the electrolyte films, such as electrochemical vapor deposition (EVD), plasma spraying, spray pyrolysis and sol-gel. Some of the technologies are not suitable for preparing the electrolyte films on a large scale and their extended application in the SOFC is limited due to either complicated equipment or expensive costs. So, simplifying the processes of preparation and reducing the fabrication cost for the electrolyte films have become a major issue. In the present paper, a series of ceramic powder processing methods were investigating for preparing the YSZ (Yttria stabilized Zirconia) electrolyte film on NiO/YSZ substrate with low cost. The properties of SOFCs with thin-film were studied.Firstly the performances of anode substrate-Ni/YSZ cermet were investigated. Theresults showed that the specific surface area of YSZ powder could be changed by pre-calcining at different temperature. Accordingly, the performances of Ni/YSZ cermet might be changed too. The value of total shrinkage of Ni/YSZ cermet doping with YSZ pre-calcined at 900℃ for 2h (NZM900) is closer to that of YSZ electrolyte. NZM900 also has more proper porosity of open holes and higher conductivity. The results of single fuel cell indicate that the performances of anode with raw YSZ powder (NZM) are the best, but the performances of NZM900 are closer to it. NZM900 is a perfect anode substrate for the appliance of SOFCs operating at intermediate temperature.In this thesis, a gravity deposition method (GD) was investigated based on the mechanism of YSZ particles' spontaneity depositing onto supporter to form electrolyte film in the meta-stable YSZ/ isopropanol suspension system. The technical condition of preparing YSZ thin-film on NiO/YSZ anode substrate using GD method was investigated. The best condition of preparing YSZ suspend used in gravity deposition is: the solvent is isopropanol,...