Research On Fabrication Of Impregnation Anode And Performance For Intermediate Temperature Solid Oxide Fuel Cell

The performance of Solid Oxide Fuel Cell is closely related to the microstructure of the anode,optimization of the microstructure of the anode can improve the performance of the cell. Ion impregnation method is one of the important method which used to prepare nano-structured high–performance SOFC.In this study,we prepared an anode of Solid Oxide Fuel Cell by ion impregnation.In order to meet needs of preparation of big plate single cell which used graphite as pore-maker,first,we used different methods to modify graphite to improve its wettability and to increase the surface oxygen groups,and then to improve the dispersion of graphite in the water systems;then,we used YSZ powder and pore-maker(nitrification graphite)as raw materials to prepare a high porosity YSZ layer / YSZ dense layer complex matrix as the impregnated carriers,then impregnated the carriers in the nickel nitrate saturated solution and the propionic acid -nickel complex solution,respectively. After repeated dipping,drying and calcining,we obtained the half-cell with nickel catalyst,coating the cathode on the half-cell to get the single cell. The crystalline phase and microstructure of anode were characterized by XRD and SEM,the NiO crystal in the anode were both nano-crystal,but the NiO crystal which impregnated in the propionic acid-nickel complex solution is obviously smaller than those impregnated in the nickel nitrate saturated solution;By adding the propionic acid,can increase the content of the nickel in the solution to enhance the impregnation rate ,it also can reduce the size of NiO crystal and inhibit the NiO aggregation to increase the length of the three-phase reaction zone in anode;with the increase of propionic acid and nitric acid molar ratio (R),the size of the NiO crystal showed a descreasing trend,the range of the NiO crystal was 20nm 40nm,when the R value is 1.5,the size of NiO crystal of 20nm;at 750℃,the maximum power density of single cell which prepared by impregnated in propionic acid -nickel complex solution(1.135W/cm²)is higher than it prepared by impregnated in the nickel nitrate saturated solution(0.719W/cm²).A YSZ porous layer / YSZ dense layer complex matrix which has good mechanical properties and high porosity is the key to prepare SOFC anode by ions impregnation,and it is the first problem to slove,if we want to do the next experiments. Therefore,in this work,we studied on preparing the YSZ porous layer / YSZ dense complex matrix.We studied on sintering the dense layer and porous layer,and the particle sizes of the graphite and the type of the binder impacting on composite matrix,and then determined the best combination.The experimental results shown that D50=90nm YSZ powder and nitrification graphite powder which was modified in dilute nitric acid under the microwave conditions in accordance with the mass ratio of 10:7,and PVA as binder to prepare YSZ porous layer / YSZ dense layer complex matrix,it had good mechanical properties and the porosity of porous layer is 50vol.%.In addition,in this study,we discussed the different preparation methods on the anode and the content of the nitrification graphite and the amount of catalytic active components by impregnation impacted on electrical properties of single cell. The experimental results showed that the anode which used the complex matrix with 70wt.% nitrification graphite content as a carrier,and NiO-impregnated amount was 50wt.%,operated temperature at 750℃in the H₂ environment,the corresponding single cell has the highest power density.