Preparation And Performance Of Cobalt-based Double Perobskite Cathode Materials PBCM_x(M=Cu,Ni) For Intermediate-temperature Solid Oxide Fuel Cells

The solid oxide fuel cell?SOFC?is widely regarded as the most promising energy output device,due to the advantages of high efficiency,low pollution and high power density,have aroused wide concern.SOFC can convert chemical energy directly into electrical energy by redox reaction.Traditional SOFCs have high working temperature?¹000 ??,high operating temperature leads to degradation of SOFC,and the connection materials react and restrict the selection of materials.Therefore,reducing the operating temperature of SOFCs from 1000 ? to intermedium temperature range 600-800 ? can avoid these disadvantages,such as short life of materials,high cost and low material selection.Therefore,IT-SOFC is one of the most promising ones.In recent years,the cathode materials of IT-SOFC have been studied extensively.The cathode reaction requires high activation energy,lower operating temperature means less power for redox reaction,and lower its performance.So,many researchers are working on developing new cathode materials to improve the efficiency of the SOFC in the Intermedium temperature range.In the Intermedium temperature range,to obtain the maximum power density of the SOFC,the cathode material is the ion-electron conductor.The cathode reaction occurs at the interface of electrode electrolyte and gas.The cathodic reaction area of the pure electron conductor is limited to the surface of the electrolyte,and the broadening of the reaction area can only change the microstructure of the cathode.In contrast,a mixture of conductive material,because of its oxygen ion conduction,can spread through the entire cathode layer,so that the reaction area is expanded.The traditional high temperature cathode material was strontium lanthanum?LSM?,which was later replaced Mn by Co to make new cathode material?LSC?,and in Fe-doped?LSCF?cathode.BaCo_0.7Fe_0.2Nb_0.1O₃-_??BCFN?showed better electrochemical properties.The double perovskite oxide has attracted people's attention due to its unique structure.Double perovskite Pr BaCo₂O_5+?cathode has been proved to be a development prospect of IT-the SOFC cathode material,but its thermal expansion coefficient and electrolyte gap is big,is not conducive to the SOFC work stably for a long time,it needs to be improved.Based on PrBaCo₂O_5+?cathode materials doping transition metal Cu,Ni,to reduce the cathode materials of thermal expansion coefficient,improve cathode and electrolyte thermal matching degree,thus achieve the result that improve the performance of the SOFC.PBC_2-xC_x andPBC_2-xN_x cathode materials were made by adding a different proportion of Cu and Ni to PrBaCo₂O_5+?,and the feasibility of it as IT-SOFC cathode was further studied.1.PBC_2-xC_x?x=0.0,0.1,0.2,0.3,0.4,0.5?was prepared by EDTA-sol gel method.The XRD test results of 1000 ? sintering 10h show that all samples have formed a single phase perovskite structure.The thermal expansion coefficient of the sample is reduced with the increase of doping amount.The conductivity of PBC_1.7C_0.3 cathode was the highest in 300-800 ?.The polarization resistance of PBC_1.7C_0.3 cathode on SDC electrolyte was 0.0162?cm² at 800 ?.PBC_1.7C_0.3 as cathode,SDC as electrolyte,Ni_0.9.9 Cu_0.1-SDC as anode,the maximum output power density was531.92mW/cm².2.Using EDTA-sol gel method,PBC_2-xN_x?x=0.0,0.05,0.10,0.15,0.20?cathode material was prepared.The XRD results of 1100 ? sintering 10h indicate that all uniphase is good.With the increase of the doping amount,the thermal expansion coefficient is reduced,and the cathode conductivity is the highest when the doping quantity x=0.15.PBC_1.85 N_0.15 cathodic polarization resistance on the SDC electrolyte is 0.030?cm²,PBC_1.85N_0.15.15 is the cathode,SDC is electrolyte,Ni_0.9 Cu_0.1-SDC is the anode,the maximum output power density is 510.37m W/cm² at 800 ?.