Fabrication And Performance Of Sulfur Tolerant IT-SOFC Based On Composite Anode Support

Solid Oxide Fuel Cells (SOFCs) is an all solid state energy conversion that can transform chemical energy of fuels directly into electrical energy by electrochemical reaction. As a new energy transforming technology, it has the advantages of high energy conversion efficiency, environmentally friendly, Nonnoblemetal catalysts, fuel adaptability, etc. In respect of sustainable development and environmental protection, seeking new energy solutions is imperative, and fuel cell technology is extremely promising, therefore, it has attracted many people's attention and research. After about three decades of rapid development, solid oxide fuel cell technology has begun to move toward marketization and industrialization. In order to reduce the cost of manufacture and use, an important issue for the recent developments of solid oxide fuel cell technology is fabrication of thinner electrolyte membrane to achieve low operatingtemperature. At the same time, developing new type anode materials which are good at redox cycle, wide fuel adaptability and excellent electrical conductivity had been proved to be beneficial to the practical application of IT-SOFC. The main research of this thesis lies in fabrication of the bilayer made up of porous YSZ substrate supported dense 10Sc1CeSZ electrolyte thin film andpreparationof sulfur tolerant anode by impregnation. On this basis, the preparation of the intermeddle temperature SOFC(IT-SOFC), and the characterization and evaluation of single cell performance are carried out at last. The specific tasks are as follows:Chapter 1outlines fuel cells technology, a brief introduction of the SOFC working principle, classification, the key materials performance requirements, as well as the SOFC technology research, development status and trends, Finally, proposes the main research objective of this paper.Chapter 2 analyzes the characteristics of frequently-used SOFC materials (electrolyte, anode, cathode), and synthesizes 10Sc1CeSZ, CGO, LSC powders.Chapter 3 introduces the fabrication of bilayer, YSZ green tape was prepared by tape-casting technique, 10Sc1CeSZ electrolyte was deposited on it by screen printing. The bilayer of porous YSZ substrate supported dense 10Sc1CeSZ electrolyte thin film was successfully obtained after the co-sintering process. Then, CGO and LSC films were deposited on the surface of the 10Sc1CeSZ successively by screen printing method. The chapter also discusses the common defects occurring during the fabrication of single cell using tape-casting, screen printing and co-sintering methods and puts forward the possible solution.Chapter 4 analyses the necessity of developing novel SOFC anode materials. V₂O₅-CuO-YSZ and V₂O₅-LaCrO₃-YSZ composite anodes were acquired by impregnation. Microstructures analysis of composite anodes were made by SEM, andkey issues in impregnation method were discussed.Chapter 5 tests the single cell performance, At 800°C, using humidified pure H2 and syngas(40%H2, 60%CO)containing 5200ppmv H2S as fuels, the open cell voltage (OCV) of single cell with V2O5-CuO-YSZ composite anode were 1.06 V and 1.05 V, respectively, and the maximum power densities were nearly same with the value of 37 mW/cm2; the open cell voltage (OCV) of single cell with V2O5-LaCrO₃-YSZ composite anode were 1.08 V and 1.07 V, respectively, and the maximum power densities were 41 mW/cm2 and 35 mW/cm2. The testing results demonstrated that the cells with the impregnated VOx-Cu/ VOx-LaCrO₃ had stable performance fed by H2S containing-syngas.Chapter 6 outlines the current research on A-sitedopedperovskite SrTiO₃ as a new kind of materials in SOFC anode. LST(La0.2Sr0.7O₃)has been proved to be a promising SOFC anode material, which possess high electronic conductive and good redox cycle ability. LST/10Sc1CeSZ bilayer was manufactured by using LST instead of YSZ as as support, a preliminary exploration on preparation of a single cell is carried out.Chapter 7 summarizes the initial results obtained by the present thesis work, proposes problems found in the premier experiment process and the corresponding measures for improvement, and finally put forward direction for future research prospects.