BaCo_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ)离子-电子混合导体电导性能研究  

Research on conductivity properties of BaCo_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ) mixed ionic-electronic conductor

作　　者：袁强[1] 甄强[1,2] 李榕[2] 谭威[2] 

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]上海大学纳米科学与技术研究中心,上海200444

出　　处：《功能材料》2014年第7期7051-7056,共6页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(51072112;51311130110);上海市高校青年教师培养计划资助项目(B.37-0407-12008);攀枝花市科技局产业推进资助项目(2012CY-S-18);上海大学创新基金资助项目(sdcx2012033;sdcx2012062)

摘　　要：用四电极法研究了 BaCo0．7 Fe0．2 Nb0．1 O 3-δ（BCFN）离子-电子混合导体的总电导率随温度的变化规律；通过阻塞电极法测量了 BaCo0．7 Fe0．2 Nb0．1 O 3-δ氧离子电导率随温度的变化规律；通过计算得到了电子电导率随温度的变化规律.研究结果表明,在温度低于550℃以下时,电子电导起了决定作用,随着温度的升高总电导率和电子电导率均呈现出显著增加的趋势,表现为 P 型半导体特征；当温度在550~650℃时,由于晶格氧的脱附,消耗了自由电子,导致电子电导率略有下降,使得总电导率表现出类似的变化规律,通过计算得到在550℃以下 BCFN 混合导体的电子电导的表观活化能为0．30 eV；当温度高于650℃以上时,由于氧空位增加导致氧离子电导率随温度升高迅速增大,使得总电导率又呈现增加的趋势,计算得到氧离子迁移活化能为1．18 eV；O 2-TPD 研究结果证明了在550~650℃时存在明显的晶格氧的脱附峰,晶格氧的脱附显著影响了 BCFN 混合导体电子电导率和总电导率.当温度低于650℃以下时,电子的迁移数接近100％,当温度高于650℃以上时,氧离子的迁移数迅速增大,900℃氧离子迁移数可达到8．97％.In this paper,the rules of conductivity of BaCo0.7 Fe0.2 Nb0.1 O 3 -δ（BCFN）ionic-electric mixed conductor changing with temperature was studied by the four-probe method;the ionic conductivity of BCFN changing with temperature was obtained by the electrode-blocking method and then calculated the electric conductivity.As our results revealed,the electric carriers play an dominant effect in the conductor and electronic transport number was near 100% when the temperature was below 550 ℃.The whole conductivity and electric conductivity in-crease rapidly with the evaluating temperature,which exhibits a characteristic of P-type semi-conductor with the apparent electric activation energy of 0.30 eV.When the temperature is at the range of 550-650 ℃,the elec-tric conductivity decreases because of electric carrier consumption resulting from the lattice oxygen desorption. Since the oxygen vacancy increases when the temperature was above 650 ℃,the ionic conductivity and oxide-ionic transport number increase rapidly with rising temperature and enhance the whole conductivity as well.The oxide-ionic transport number was up to 8.97% at 900 ℃.The calculated migration activation energy of oxygen vacancy here was 1.18 eV.Moreover,the desorption peak observed in the O 2 -TPD experiment at the range of 550-650 ℃ provides a powerful proof of the lattice oxygen desorption,which make a remarkable effect on the ionic conductivity and whole conductivity of BCFN.

关 键 词：BaCo0 7Fe0 2Nb0 1O3-δ 总电导率 离子电导率 电子电导率 

分 类 号：TQ132.35[化学工程—无机化工]