Synthesis And Characterization Of Ce_0.8Sm_0.2O_2-δ Electrolyte Powders

Nowadays, improving energy effeiency is important to decrease the pollution from fossli fuels comsumption. Solid oxide fuel cells (SOFC), which convert chemical energy of fuels to electricity directly, can improve energy efficiency greatly. SOFC is also a kind of environment friendly energy conversion device because of the products of reaction are carbon dioxide and water. Electrolyte is the core part of SOFC, the function of it is not only as a block layer to separate cathode from anode, but as a carrier to transfer oxygen ions from cathode to anode. Electrolyte layer is the dominant part of SOFC’s internal resistance because of its low ionic conductivity, and thin film is a direct and effective way to figure out it. Therefore, it’s important to research SDC powder in order to achieve the electrolyte layer’s thin and densification.Ce0.8Sm0.2O2-δ (SDC) is one of SOFC’s electrolyte materials because of its high oxygen ionic conductivity. This paper research content, including SDC powders synthesized by solid-phase reaction and nitrate combustion methods, and powders synthesized by solid-phase reaction will be dealed with wet ball-milling in order to get good sintering performance. Different chemical dispersants and ultrasonic impact on powders granulometric analysis, and study the thermal dynamic of different methods preparation SDC, nickel based and copper based anode powders, in order to prepared good properties of single cell. Detailed research contents and conclusions are as follows:1、Solid oxide fuel cell and its key materials research were reviewed.2、Influence of disperants and ultrasonic dispersion for CeO2ceramic powders in granulometric analysis. Experimental research the effects of different chemical dispersants added and ultrasonic dispersion for CeO2powders granulometric analysis, and the dispersion mechanism were discussed. Results show that with ammonium carbonate and detergent as dispersants can better disperse CeO2powder in water, and ultrasonic treatment can further improve the effect of dispersion.3、Apply research of high sinterability SDC powders synthesised by wet ball-milling. We study medium, speed, ball size and ball-milling time impacts on particle size and its distribution of SDC powders synthesized by solid-phase reaction. SDC dense electrolyte preparation by ball-milling SDC powders with the optimal process. Results show that with φ=2mm Z1O2grinding ball, ball-milling speed more than300r/min, adding ethanol grinding aid as medium, achieve the minimum size of SDC powders in1hour, D50is about1.19μm. With the500r/min ball milling speed for2hours, the preparation of the SDC layer through1400℃sintering of5hours, the preparation of SDC electrolyte layer maximum relative density, about94.7%. Ball-milling can effectively reduce particle size and distribution in order to improve sintering process. But longer time of ball-milling will hampering the SDC densification sintering process by ZrO2grinding balls wastage.4、Property research of SDC powders synthesised by nitrate combustion. We study adding combustion adjuvants impact on SDC powders phase state, powder fluffy and SDC layer density. Results show that methylcellulose as the combustion adjuvant, can better realize the SDC powders into phase, powders lowest apparent density of0.13g/cm3, the relative density of SDC decreases with the increase of adding amount of methylcellulose, can achieve maximum density at1300℃sintering temperature, about89.2%. Experimental research show that with small molecular ethylene glycol as combustion adjuvant has good effect on SDC powders, can achieve maximum density at1300℃sintering temperature, about91.3%, powders lowest apparent density of0.063g/cm3.5、Sintering dynamics research of SDC electrolyte and SDC/NiO(CuO) anode. Study the effect of the thermal dynamic process of solid state phase method and nitrate combustion method for the preparation of SDC-NiO and SDC-CuO powders, and the effect of adding starch pore-forming for thermal dynamic process, lays a foundation for preparation good physical properties of anode-electrolyte half cell structure and single cell.