Study On The Fabrication Of YSZ Nanoparticle Modified SOFC Anode

Solid oxide fuel cell (SOFC) is one kind of solid-state energy conversiondevice that can convert fuel’s chemical energy to electrical energy directly.SOFC possesses several advantages, such as environmental friendly, highconversion efficiency and fuel versatility, which has great potential forcommercial applications. At present, to achieve the intermediate or lowtemperature SOFC is the research tendency. Optimizing the electrodemicrostructure and obtaining thin electrolyte can reduce the SOFC operatingtemperature effectively. Nano-materials offer an option to ameliorate themicrostructure of components and improve the performance of SOFC. In thisdissertation, in order to optimize the microstructure of anode support and extendthe length of three phase boundary, nano-YSZ particle infiltration layer wasprepared between the anode substrate and electrolyte.The NiO/YSZ anode support was prepared by dry pressing method. Throughthe study of the content and choice of binder and pore former, the optimumproportion of PVB binder and spherical graphite pore former were determined.Then the pre-sintering temperature was investigated as well. The result suggestedthe anode support has the best microstructure with the addition of4wt%PVB,25wt%spherical graphite and pre-sintered for2h at1100℃. It was utilized asthe substrate for further study.Nano-YSZ particle infiltration layers were prepared on the anode support byslurry spin coating method. The microstructure of nano-YSZ infiltration layerswere studied with the influence of the solvent of slurry, the content of nano-YSZand EC dispersant and spin coating cycles. It was found that the thickness ofnano-YSZ infiltration layer can reach23.2μm after spin coated three cycles withterpineol solvent,5.35wt%nano-YSZ particles, no EC dispersant. The influenceof sintering temperature to the growth of nano-particles was also studied. Inorder to avoid serious sintering of nano-particles, the sintering temperatureshould be no higher than1300℃.In order to minimize the influence of electrolyte’s sintering densification of nano-particles, Bi2O3was added as sintering aid to reduce the sinteringtemperature. By studying the electrolyte density with Bi2O3amount and sinteringtemperature, the Bi2O3amount and sintering temperature were optimized. Then adense YSZ/Bi2O3layer was prepared by slurry spin coating. Dense electrolytelayer with a thickness of23.6μm was obtained under the following parameters:the content of Bi2O3and YSZ mixed powder is30wt%, the spin coating speed is3000r/min, the spin coating time was30s, repeating the spin coating process for3cycles.