Research On Fabrication Process Of Single-chamber Solid Oxide Fuel Cells

Solid Oxide Fuel Cell (SOFC) is an energy conversion device that produces electricity directly from fossil fuels by electrochemical reactions. It has advantages such as higher energy conversion efficiency, no noise and pollution. As a novel type fuel cell, Single-Chamber Solid Oxide Fuel Cell (SC-SOFC) is getting much more attention for its easy design and simple composition. So far,Much research has focused on optimizing powder synthesis method and cell fabrication to enhance the performance.We used different methods to fabricate the anode,electrolyte and cathode materials and investigated the effects of parameters on the performance of SC-SOFC.Precipitation method was used to prepare NiO powders which had good crystal, and its average particle size was 10nm. Nanometer yttria stabilized zircon (YSZ) powders were prepared by means of glycine-nitrate process (GNP). The average crystallite size of the YSZ powders was about 30nm. Strontium-doped lanthanum manganese oxide La0.7Sr0.3MnO3(LSM) powders were prepared by Sol-Gel method. The average diameter of the catalysts,observed by the Transmission Electron Microscope (TEM),was 40-80nm.Anode-supported single-chamber solid oxide fuel cell (SC-SOFC) with dense 20μm thick YSZ film as electrolyte was fabricated by slurry spin coating technique,the structure of the cell was NiO-YSZ/YSZ/LSM. The electrolyte has good gas tightness, it had tight integration with the anode and not with the cathode. We studied the impaction of the temperature on the performance of the cell. The result showed that the cathode had lower catalytic performance at higher temperature. CH4 was partial oxidized at the higher temperature, so the Open Cell Voltage (OCV) became lower.A co-pressing and direct forming process has been developed for preparing SC-SOFC, which consist of YSZ electrolyte, NiO-YSZ cermet anode, and LSM cathode. The Scanning Electron Microscopy(SEM)results show the tight integration between the cathode and electrolyte, the thickness of YSZ electrolyte film was about 50 um. The single cell was smooth without any deformation, it had good thermal stabilization. The YSZ three-dimensional framework was fabricated and it could be loaded by LSM catalyst quickly to form long Three Phase Boundary (TPB). The studies on SC-SOFC involved the dependence of the properties of single cell on temperature (T), the number of catalyst loading layers (n) and the volume ratio of CH4 and O₂ (Rmix=V(CH4)/V(O2)). At T=800℃,n=2,Rmix=2, the single cell has the best performance, the open voltage was 0.95 V, the maximum current density was 130 mA.cm^-2, the maximum power density was 30 mW.cm^-2.. Co-pressing and direct forming process has advantages such as simple device,short preparation cycle,handy operation and so on.