Research On The Anode And Electrolyte Material Of IT-SOFC

Solid oxide fuel cell(SOFC) is an all solid-state energy conversion device operated at high temperatures with the advantage of high efficiency,little pollution.It has been considered as the "green power technology" in the 21^st century.However,at present,there are so many basic problems about SOFC not solved,such as the material and fabrication of SOFC.Combining the status and trend of R&D in the field of SOFC and the conditions in our laboratory,this paper consist of several parts as following:A anode-supported SOFC operated at intermediate temperature(600-800℃) has been made.The preparation methode of anode material NiO-CGO and the structure of electrolyte have been improved.The main work and conclusions of this paper are as follows:(1) The electrolyte and cathode material,Ce_0.85Gd_0.15O_2-a and Ba_0.5Sr_0.sCo0.5Fe_0.2O_3-a are prepared by citric acid sol-gel.The X-ray diffraction is used to study the structural property. Ni-CGO/CGO/BSCF anode-supported PEN for solid oxide fuel cell is fabricated.Anode substrate with thin film CGO electrolyte and BSCF cathode are fabricated by dry-pressing process,slurry coating process,respectively.Heat and inner press are the main factors of anode substrate warp and crack.When the cell is tested with hydrogen at the anode and air at the cathode in the temperature range of 600-800℃,it yield open-voltages(OCVs)of 0.78-0.85V,the peak power density of 118.46mW/cm²,the peak current density of 487.17mA/cm².(2) NiO/CGO cermet anode material is prepared by coating precipitation method.The X-ray diffraction is also used to study the structural property.The TEM and EDX are used to observe the micro-structure of the anode grain.The effect of the pH to the preparation has been studied.SOFC anode formed a continuous network structure with this NiO coated by CGO material.This means that the CGO coating layer on the NiO surface using the coating precipitation method efficiently prevent the sinter and agglomeration of Ni.When the cell is tested in the temperature range of 600-800℃,the peak power density reach 129.74mW/cm², the peak current density reach 551.28mA/cm²,which are higher than the cell with normal anode.(3) In this paper,a new methode to fabricate the cell is proposed.We attempt to improve the tradition methode by inserting a new BCY layer next to the CGO layer.The BCY is chosen as the intermediate layer material due to high reduction resistance.The thickness of the CGO and BCY are about 25μm and 20μm,respectively.When the cell is tested in the temperature range of 600-800℃,it yield open-voltages(OCVs)of 0.83-0.94V,which are higher than the OCVs of 0.78-0.85V obtained for a single-layered CGO electrolyte cell under the same conditions.