Fabrication Technics And Properties Of Solid Oxide Fuel Cell's Honeycomb Body Prepared By Tape Casting

Solid oxide fuel cell(SOFC)is an energy conversion device that produces electricity directly from fuels by electrochemical reactions.Being several advantages,such as higher energy conversion efficiency,no pollution and good fuel adaptiveness,SOFC has been received considerable interests worldwide.Recent SOFC development has been focused on lower temperature operation less than 800℃.There are three approaches for lower temperature operation:applying new materials which have high conductivity,using a thin film of electrolyte as well as applying new SOFC structure.In the new SOFC structure's research,the honeycomb is considered to be advanced.The honeycomb SOFC have a lot merits,such as high specific area and power density,no need of elevated temperature sealing and supporting element,small volume and weight.In this dissertation,the fabrication processes of SOFC's honeycomb body have been exhaustively studied.Detailed work is as following:The compact YSZ slice has been prepared by Tape casting.The factors which influence the viscosity of slurry have been studied.The technical parameters and the drying process in the tape-casting process have been studied respectively.The batching curve has been made according to the TG analysis of green tape.The results show that the slurry is suitable to tape casting when the YSZ content is 45wt.%,milled 48 hours;the smooth green tape with high density can be gained by limiting the tape velocity at 0.6mm/s and the temperature at 25℃when drying in the solvent atmosphere.The relative density of YSZ slice sintered at 1350℃for 3h with heating rate of 1℃/min is 95.2%.The porous electrode has been prepared by tape casting with the addition of amylum as poreformers.The XRD analysis show that the main phase of Ni-YSZ sintered at 1250℃,1300℃,1350℃for 3h are YSZ,Ni and NiO.The main phases of LSM-YSZ sintered at 1250℃ and 1300℃are LSM and YSZ,but the main phases sintered at 1350℃are LSM,YSZ and few La₂Zr₂O₇.The shrinkage and porosity of electrode are increased with increasing the amylum content.The pores of the electrode are distributed homogeneous and the aperture's scope is 1～10μm.The SOFC's honeycomb body has been prepared by winding,stacking and heat sealing the two dimensional slices prepared by tape casting.The heat sealing process and sintering curve have been investigated.The micro pattern,EDS,thermal shock resistance and compressive strength have been tested and analyzed.The results show that the SOFC's honeycomb body prepared by this method has regular shape,the ratio of open pores is high.The combination of the electrode and electrolyte is good.The elements of anode and cathode are diffused in the wall of hole.The honeycomb body has good thermal shock resistance.