Study On Preparation Of Anode Supported Solid Oxide Fuel Cells By Slurry Spin Coating

Solid oxide fuel cell (SOFC) is an all solid-state energy conversion device thatproduces electricity by direct conversion of chemical energy from fuel. It hassubstantial potential in the commercial application with the merits of highefficiency, low pollution and fuel versertality. To achieve the intermediatetemperature range operation (600～800℃) is the current tendency for SOFCs. Toobtain high cell performance at a reduced temperature, great efforts should be madeto minimize the polarizations of a cell, including electrolyte ohmic polarization,activation polarization and concentration polarization for both cathode and anode.Firstly, the effects of pore formers on the anode performance were investigated.The pore formers play an important role in increasing the porosity in anodesupporter so as to optimize the anode structure and improve the performance of thecell. In this paper commercial NiO powder, YSZ (8mol%Y2O3-stabilized ZrO2)powders in micron range and pore formers were mixed together and dry-pressed asanode supporter. The pore formers investigated include starch, flake graphite andsphere graphite. The results suggested anode supporter with20wt.％sphere graphiteaddition is the optimized result, which could achieve33%porosity and influence thetotal sintering shrinkage of anode considerably，meet the request of SOFC anodesupporter.Secondly, anode graded functional layers (AGFLs) were prepared on anodesubstrates to increases the amount of triple phase boundarys(TPB) and theelectrochemical or catalytic activity of anode so as to reduce the anode polarizationresistance. Impregnation and slurry spin coating were used to prepare AGFLs forcomparation. Slurry spin coating is more suitble to obtain an uniform coating. Dense8mol%yttria-stabilized zirconia (YSZ) films were deposited via slurry spin coating.And the combination of anode and electrolyte were studied.Slurry spin coating was also used to prepare LSM-YSZ composite cathodes aswell, and the influence of fabrication conditions on the performance of cathodes isinvestigated. The initial parameters for slurry spin coating, such as binders’ content,slurry drops, spinning speed and sintering temperatures have direct and importanteffects on the cathode morphologies and microstructure. Explore the optimizationprocess parameters through the orthogonal experiment. The results demonstrate thatthe structure is optimized by the addition of10wt.％ethyl cellulose,3slurry drops,spin speed greater than6000r/s, sintering temperature of1000℃.Thus, the purpose of this paper is to reduce anode and cathode polarization lossthrough optimum of anode supporter’s porosity, anode gradient functional layer and cathode functional layer. What ultimately is the goal to lay a foundation for develophigh energy density SOFCs.