Research On The Preparation And Performance Of Cathode Supported Solid Oxide Fuel Cell

Solid oxide fuel cell?SOFC?is energy conversion devices that convert the chemical energy of fuels directly into electrical energy through electrochemical reactions.This kind of conversion mode has many advantages such as high efficiency,low emission and strong adaptability of fuel,so it has been widely concerned by the society.But traditional SOFC needs to run at high temperature?800-1000??to ensure that the cell has sufficient power density.High temperature operation of SOFC,however,increases cost and delays its commercialization.How to realize the SOFC running at lower temperature is a challenge for researchers.This paper mainly focuses on the selection of cell materials and preparation methods to achieve a lower temperature.?1?A site deficient LSM95 cathode powder was synthesized by using solid reaction process,through XRD characterization,to determine the LSM95 have stable perovskite structure,and have good chemical compatibility with SSZ electrolyte at as high temperature as 1250?.After measurements of thermal expansion coefficient,we confirmed that the 3YSZ,LSM95 and SSZ in 25-800?has good thermal compatibility.The superior conductivity of LSM95 and SSZ was confirmed by measuring the conductivity of the materials.By measuring the porosity and conductivity of 3YSZ-LSM95 composite cathode material,the mass ratio of 3YSZ and LSM95 powder was determined to be 5:5.The amount of carbonized starch is10%wt..?2?NiO-SSZ|SSZ|LSM95-3YSZ single cells of electrolyte supported type were prepared with dry pressing method,the power density of them between 600-800?was 22.07?32.45?56.13?87.01 and 125.12mW/cm²,respectively.Cathode supported NiO-SSZ|SSZ|LSM95-3YSZ single cells were prepared by tape casting and co-sintering,the power density of the cells between 600-800?,was 7.16?13.49?23.12?35.64 and 49.76 mW/cm²,respectively.The power density data of these tape casting cells are not satisfactory,from the literature we get to know that adding a transition layer between the active cathode and the electrolyte layer can effectively improve the power density of cells.So the next step is to add a transition layer,and then study the performance of the cells.?3?Because the performance of cathode supported cell NiO-SSZ|SSZ|LSM95by tape casting is not satisfactory,the structure was optimized by adding a transitional layer between the support layer and the electrolyte layer and getting the three layer structure of cathode supported SSZ|SSZ-LSM95|LSM95-3YSZ half cells.Then NiO-SSZ and NiO-CGO composite anodes were prepared on the three-layer structure with screen printing method.Using H₂ as fuel,the power density of the cells was tested between 700-900?,those with the composite anode of NiO-SSZ showed 63.27?83.23?115.32?135.71and 162.58 mW/cm²,respectively,while those with NiO-CGO as composite anode showed 36.69?50.59?63.69?75.36 and 86.73mW/cm²,respectively.Comparing with the performance of cathode supported cell NiO-SSZ|SSZ|LSM95-3YSZ,the performance of the cells with the addition of transition layer is significantly increased,indicating the necessity of adding the transition lay to the cathode supported SOFCs.?4?LSCrM anode powder was synthesized by sol-gel method.Its crystal structure was characterized by XRD.The cathode-supported SSZ|LSM95-3YSZ double layer structures were prepared by tape casting,and the LSCrM-CeO₂ anode was prepared by dip coating method.The effects of different dip coating amount on the performance of cells were studied.The performance of the cells showed no significant attenuation,indicating that the cell had no carbon deposition in the methane atmosphere.From the SEM diagram of the cell after the test,it could be seen that there were almost no carbon particles on the surface of the anode,which further confirmed that the LSCrM-CeO₂ anode material had certain anti-carbon deposition ability.Then CH₄ as fuel,this paper discusses the LSCrM-CeO₂ carbon deposition resistance of the anode materials,the power density between 600-800?,respectively1.68?4.70?12.40?28.08 and 54.78mW/cm².By small current density of 46.50mA/cm²discharging test,power density before and after test is respectively 54.78 and 68.2mW/cm².This paper has 60 pictures,11 tables and 113 references.