On the copper doping of La0.8Sr0.2MnO3 (LSM) cathode for IT-SOFCs

• Main Authors: Feng-Nien Yen, 嚴豐年
• Other Authors: Jing-Chie Lin
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/8wtf2n

碩士 === 國立中央大學 === 材料科學與工程研究所 === 107 === In this study, the nanostructured perovskite La0.8Sr0.2MnO3 (LSM) and La0.8Sr0.2Mn1-xCuxO3 (note as x=0.1; LSC1M, 0.2; LSC2M, 0.3; LSC3M) prepared by the glycine-nitrate combustion synthesis method were considered as a potential candidate for use as cathode in solid oxide fuel cells (SOFC) operated at intermediate-temperature. In the present work, combustion synthesis method was investigated by adjusting the pH of LSM nitrate solution (pH=2, 3, 4, 5) and ratio between glycine and nitrate (G/N= 0.75, 1.00, 1.25). The crystal structure and morphology of the powders after calcining were analyzed and also its thermal properties and electrochemical characteristic were discussed. The optimal combustion synthesis parameters (pH and G/N) were used to synthesize the LSCxM. Then the crystal structure and electrochemical properties were investigated. Finally, the feasibility for using as cathode in P-SOFC though combining LSM as cathode backbone and doping Cu to replace Mn. The results of LSM analysis showed that LSM1.00/3, LSM1.00/4, LSM1.25/3 and LSM1.25/4 were the optimal parameters for combustion synthesis whose crystal structure and morphology were the most suitable as cathode for SOFC. Among all, LSM1.25/4 was analyzed that its average particle size around 30nm. For the measurement of thermal expansion coefficient (TMA), the coefficient of LSM1.25/4 was about 14.36 × 10-6 K-1 which was the closest to that of electrolyte BCZY. In the results of four-probe DC conductivity measurement, LSM1.25/4 had the highest conductivity near 495.38 S/cm.The performance test results show that the highest power density is 41.8 mW/cm2 at 800 °C, and the experiment of doping copper into LSM found that the conductivity analysis has the highest conductivity increase in LSC2M, from 495.38 S/cm improved to 858.26 S/cm. The performance test showed that the LSM4/1.25 doped 0.2 copper-substituted manganese had a 60% improvement in efficiency, and the operating temperature was increased from 22.33 mW/cm2 to 37.20 mW/cm2 at 700 °C. The resistance Rp drops by 4.55 Ωcm2.