Research Of Porous Ceramic Supported Solid Oxide Fuel Cell

The solid oxide fuel cell (SOFC) is a new kind of solid-state energy conversion equipment with the merits of high efficiency and low pollution, which is received widely attentions by researchers. In this paper, the porous ceramic supported SOFC was prepared and investigated. The plaster mold slip casting technology with low cost was developed to prepare the porous ceramic tube. On these bases, the single cell and the stacks were prepared and the electrochemical properties were studied systematically, which lays a foundation for the cell stack with high performance.Partially stabilized zirconia (PSZ) porous-supported tube was fabricated via slip casting. The slurry was prepared using tapioca as porous agent, because of the larger particles of the tapioca, supporting tube was easy to produce the defects and the yield was low when fabricated support with high porosity. While the NiO was used as the pore former and prepared the slurry containing high solid content, which overcomes the disadvantage of the low yield used the tapioca. The optimal composition of the slurry was determined by the stability of the slurry. The contents of ingredients are 10g PSZ powder, 10¹2g pore former (NiO), 2.5g dispersant (Arabic gum), 20g solvent (water). The green bodies were fired at 1100°C first, the support with high mechanical strength and porosity of 30⁴0% were obtained after acid cleaning the metal Ni in the support. The support with acid cleaning the Ni has small aperture and uniform distribution, which can help gas diffusion.The anode layer (NiO/YSZ) and YSZ thin film was fabricated on the porous support via dip coating method, and the anode layer was prefired at 400°C after each dipping. The porous PSZ support tube was dip coated several times to obtain anode and electrolyte layer with ideal thickness. The thickness of anode and electrolyte film was 80μm and 20μm, respectively. The cell was fabricated using LSM dipped SDC as cathode after 1100°C sintered, and the electrochemical performance of the single cell was measured. The OCV reached 1V, and the maximum power density was 89mWcm^-2 at 700°C when the hydrogen gas flow was 100sccm. As can be seen from the SEM, the as-prepared YSZ electrolyte film was fully dense. However, the phenomenon of stratification occurred in the anode, which affected the anode microstructure and limited the cell performance.In order to improve the anode microstructure, the slurry was prepared with no pore former and dried the anode at air after each dipping. The OCV of the single cell reached 1V and 0.9V, and the maximum power density reached 345mWcm^-2 and 494mWcm^-2 at 700°C and 800°C when the gas flow was 100sccm.On the base of the single cell, the two units cell stack was fabricated on the porous support. The OCV of the stack was 1.8V with the output power 16mW. Ni particles appeared agglomeration after high temperature reduction, which impact the microstructure of the anode seriously, and limited the performance of the stack. Thus, the key of improving the performance of the stack is to improve anode treatment process and anode microstructure.