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Synthesis and characterization of calcium and manganese-doped rare earth oxide La_(1-x)Ca_xFe_(0.9)Mn_(0.1)O_(3-δ) for cathode material in IT-SOFC
引用本文:赵捷,李晨,孔令龙,吴雪薇,马永昌.Synthesis and characterization of calcium and manganese-doped rare earth oxide La_(1-x)Ca_xFe_(0.9)Mn_(0.1)O_(3-δ) for cathode material in IT-SOFC[J].中国稀土学报(英文版),2011,29(11):1066-1069.
作者姓名:赵捷  李晨  孔令龙  吴雪薇  马永昌
作者单位:School of Materials Science & Engineering;Tianjin University of Technology;Tianjin Key Lab for Photoelectric Materials and Devices;Key Laboratory of Display Materials and Photoelectric Devices(Tianjin University of Technology);Ministry of Education;
基金项目:Project supported by the National Natural Science Foundation of China (10704054)
摘    要:In order to develop novel cathode materials with high performance for intermediate temperature SOFC(IT-SOFC),Ca and Mn doped rare earth oxides La1-xCaxFe0.9Mn0.1O3-δ(x=0.1,0.3 and 0.5,denoted as LCFM9191,LCFM7391 and LCFM5591) were synthesized by solid state reaction(SSR) method.The formation process,phase structure and microstructure of the synthesized samples were characterized using thermogravimetry/differential scanning calorimetry(TG/DSC),X-ray diffraction(XRD) and scanning electron microscopy(SEM).The thermal expansion coefficients(TEC) of the samples were analyzed at 100-900 oC by thermal dilatometry.The electrical conductivities of the samples were measured with direct current(DC) four-terminal method from 300 to 850 oC.The results indicated that the samples(x=0.1 and 0.3) exhibited a single phase with orthorhombic and cubic perovskite structure,respectively after being sintered at 1200 oC for 3 h.The electrical conductivity of the samples increased with temperature up to a maximum value,and then decreased.The small polaron hopping was regarded as the conducting mechanism for synthesized samples at T≤600 oC.The negative temperature dependence occurring at higher temperature was due to the creation of oxygen vacancies for charge balance.LCFM7391 had higher mixed conductivity(>100 S/cm) at intermediate temperature and could meet the demand of cathode material for IT-SOFC.In addition,the average TECs of LCFM9191 and LCFM7391 were 11.9×10-6 and 13.1×10-6 K-1,respectively,which had good thermal match to the common electrolytes.

关 键 词:rare  earth  oxide  solid  state  reaction  perovskite  structure  mixed  conductivity  thermal  expansion
收稿时间:19 May 2011

Synthesis and characterization of calcium and manganese-doped rare earth oxide La_(1-x)Ca_xFe_(0.9)Mn_(0.1)O_(3-δ) for cathode material in IT-SOFC
ZHAO Jie ,LI Chen ,KONG Linglong ,WU Xuewei ,MA Yongchang ,Ministry of Education,China.Synthesis and characterization of calcium and manganese-doped rare earth oxide La_(1-x)Ca_xFe_(0.9)Mn_(0.1)O_(3-δ) for cathode material in IT-SOFC[J].Journal of Rare Earths,2011,29(11):1066-1069.
Authors:ZHAO Jie    LI Chen  KONG Linglong  WU Xuewei  MA Yongchang    Ministry of Education  China
Affiliation:ZHAO Jie 1,2,LI Chen 1,KONG Linglong 1,WU Xuewei 1,MA Yongchang 1,3(1.School of Materials Science & Engineering,Tianjin University of Technology,Tianjin 300384,China,2.Tianjin Key Lab for Photoelectric Materials and Devices,3.Key Laboratory of Display Materials and Photoelectric Devices(Tianjin University of Technology),Ministry of Education,China)
Abstract:In order to develop novel cathode materials with high performance for intermediate temperature SOFC (IT-SOFC), Ca and Mn doped rare earth oxides La1-xCaxFe0.9Mn0.1O3-δ (x=0.1, 0.3 and 0.5, denoted as LCFM9191,LCFM7391 and LCFM5591) were synthesized by solid state reaction (SSR) method. The formation process, phase structure and microstructure of the synthesized samples were characterized using thermogravimetry/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thermal expansion coefficients (TEC) of the samples were analyzed at 100–900 °C by thermal dilatometry. The electrical conductivities of the samples were measured with direct current (DC) four-terminal method from 300 to 850 °C. The results indicated that the samples (x=0.1 and 0.3) exhibited a single phase with orthorhombic and cubic perovskite structure, respectively after being sintered at 1200 °C for 3 h. The electrical conductivity of the samples increased with temperature up to a maximum value, and then decreased. The small polaron hopping was regarded as the conducting mechanism for synthesized samples at T≤600 °C. The negative temperature dependence occurring at higher temperature was due to the creation of oxygen vacancies for charge balance. LCFM7391 had higher mixed conductivity (>100 S/cm) at intermediate temperature and could meet the demand of cathode material for IT-SOFC. In addition, the average TECs of LCFM9191 and LCFM7391 were 11.9×10?6 and 13.1×10?6 K?1, respectively, which had good thermal match to the common electrolytes.
Keywords:rare earth oxide  solid state reaction  perovskite structure  mixed conductivity  thermal expansion  
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