Fabrication Of Intermediate Temperature Solid Oxide Fuel Cells And Investigation Of The Electrode Processes

Traditional citric acid method (Pechini method) was modified and Mg0.2 O3-δ(LSGM) ultra-fine powder was synthesized by the improved citric acid method at relatively low temperature for the preparation of anode supported LSGM thin film. The effects of compositions of NiO-LSGM substrates on the electrical conductivity, the microstructure parameters of the reduced substrates were investigated. A LSGM thin film based SOFC single cell with an SDC interlayer prepared by step sintering procedures was fabricated and a relatively low output performance was achieved, hi order to prohibit the occurrence of the severe reaction between LSGM and NiO at high temperature, for the first time in the world, a SOFC with an impregnated anode, 15 um thick LSGM electrolyte and LSM-YSZ composite cathode was fabricated and tested, showing a high output performance (The maximum output power density reached to above 800 mW/cm2 at 800癈 when H2 was used as fuel and air as oxidant). The causes for the relatively low open circuit potential and the chemical compatibility of the cell materials at high temperatures were also elucidated by EDX and electrochemical methods. The electrical conductivity of SSC-SDC, SSC-LSGM composite cathode and the dependence of the electrochemical properties of Ag-SSC-SDC composite cathode upon the kind of Ag powder, the ratio of the Ag powder, temperature and environmental oxygen partial pressure were systematically studied. Following these work, a high activity cathode of 20 wt% normal Ag-SSC-SDC was developed. The effects of SrO doping level, temperature and oxygen partial pressure on the electrochemical conductivity of BSCF, the electrochemical activity of BSCF as cathode in an SOFC and related problems were discussed. The electrical conductivities of Fe, Mg, Nb, Ga doped SrTiO3 and Nb, Ga co-doped SrTiO3 were measured at various temperatures and oxygen partial pressures and the activities of these doped SrTiO3 as carbon tolerantanode materials, problems and possible routes to deal with these problems were also researched.