Performance Optimization Of Lanthanum-Strontium-Manganese-Based Cathode For Intermediate Temperature Solid Oxide Fuel Cells

The solid oxide fuel cell?SOFC?is a device that can generate electricity from fuel with the highest efficiency.However,conventional SOFCs cannot be commercialized due to problems such as high operating temperatures?1000??,which can cause high costs and severe performance degradation after a period of battery operation.To solve these problems,the operating temperature can be reduced.However,the decrease in temperature will cause the polarization resistance of the battery cathode to increase significantly,which severely limits its output performance.Therefore,reducing the polarization loss of the cathode to improve the performance of the cathode has become one of the current research hotspots.The lanthanum strontium manganese(La_1-xSr_xMnO₃,LSM)cathode material formed by doping perovskite lanthanum manganate with strontium can only achieve high catalytic activity,high electronic conductivity and good chemical stability.The intermediate temperature solid oxide fuel cell?IT-SOFC?will greatly limit the application of LSM,which is due to the low oxygen ion conductivity and high activation energy of the reaction at medium temperature?600-800??.This article is based on the current hotspots on SOFC.Under the condition of intermediate temperature,based on the idea of increasing the ionic conductivity of LSM and reducing its polarization resistance,improving the existing cathode material LSM,combining the composite electrolyte material SDC-CuO and LSM,the composite cathode material LSM/SDC-CuO was prepared and corresponding single cells.The research work of this paper is as follows:?1?The purpose of this article is to improve the ionic conductivity of the electrolyte material SDC and reduce the sintering temperature of the SDC.The use of the transition metal oxide CuO can reduce the sintering temperature of the SDC and clean the grain boundary impurities of the SDC.The glycine-nitrate method was used to prepare the electrolyte material SDC and the composite electrolyte material SDC-k mol%CuO?k=0.5,1,2,3?,and the density and impedance spectra of the above samples were tested and compared.It was found that the sintering degree of SDC-0.5 mol%CuO sintered at 1000?for 5 h is similar to that of SDC sintered at 1250?and above for 10 h,and SDC-CuO with 0.5 mol%CuO content has the lowest resistance.It shows that the addition of CuO can effectively enhance the sintering and grain boundary conduction of SDC,and the effect is best when the CuO content is 0.5 mol%.?2?In this paper,SDC and SDC-0.5mol%CuO were compounded into LSM according to the above conclusions,and LSM,LSM/SDC and LSM/SDC-CuO were used as cathodes to prepare single cells.The XRD and SEM of the material and the AC impedance spectrum and electrochemical performance of the SOFC were characterized.The results showed that the polarization resistances of SOFCs based on LSM,LSM/SDC,and LSM/SDC-CuO cathodes were 0.55?cm²,0.19?cm²,and 0.10?cm²,respectively.At 800?,the maximum output power densities of SOFC based on LSM,LSM/SDC and LSM/SDC-CuO cathodes were132.1 mW cm^-2,162.4 mW cm^-22 and 212.5 mW cm^-2.Therefore,the good chemical properties of SOFC based on LSM/SDC-CuO indicate that the performance of cathode materials can be significantly improved by compounding SDC-CuO materials in LSM cathodes,which has a good development prospect.