Synthesize And Characterization Of Cathode LSMM For Intermediate Temperature Solid Oxide Fuel Cell

In order to overcome the limitations of solid oxide fuel cells (SOFC) in high temperature, the paper was focused on cathode and matched electrolyte materials for intermediate temperature SOFC. Based on different synthesis methods and B-site doping, a series of perovskite electrode and fluorite electrolyte materials were synthesized, and the properties of these materials were examined by various modern analysis methods to select proper candidates for SOFC and test their electrochemical properties for NO decomposition by SOFC.EDTA-citrate complexing method was employed to synthesize cathode material La0.7Sr0.3Mn1-xMgxO3-δ (LSMM, x= 0,0.1,0.2). The phase structure, microstructure and thermal expansion properties of the cathode material were characterized by various methods such as XRD, SEM, TG, FT-IR, and TEC test. The results showed that LSMM has trigonal perovskite structure, and their microstructures are similar. The oxygen vacancy content of the material increases with the increase of Mg content, which is benefit for oxygen reduction reaction. Compared with La0.7Sr0.3Mn03-δ(LSMO) and La0.7Sr0.3Mn0.9Mg0.1O3-δ(LSMM10), TEC for La0.7Sr0.3Mn0.8Mg0.2O3-δ(LSMM20) sample (10.6 x 10-6K-1) matches better with that of electrolyte Ce0.8Sm0.2O2-δ(SDC) (11.4× 10-6K-1), which is in accordance with the results of chemical compatibility and SEM. The electrochemical performance results showed that the oxygen reduction activity of LSMM20 is higher and it is proper to be used as cathode material.The electrolyte material SDC was respectively synthesized by EDTA-citrate complexing, co-precipitation, and GNP methods. XRD, SEM, TEM and electrochemical workstation were taken to investigate the structure, microstructure and electrochemical properties of SDC. The results showed that the crystal structures of SDC are consistent through different synthesis methods; SDC and the chosen LSMM20 have good chemical compatibility; the performance of single cell is superior when the electrolyte is synthesized by GNP method.EDTA-citrate complexing method was employed to synthesize the cathode material LSMM20, and it was used as catalyst for NO decomposition by the use of fixed bed. The results of catalysis performance test indicated that the conversion rate of the NO reaches the maximum value of about 98.6% at the operation temperature of 600 °C. Electrochemical performance of single cell was studied with configuration of Ni-SDC/SDC/LSMM. As 0.5% NO applied as the cathode gas and 10% H2 fed to the anode chamber, the cell reached a maximum power density of 13.06 mW·cm-2 at 700 °C.