新型混合离子-电子导体Sm_(0.9)Ca_(0.1)Al_(1-x)Mn_xO_(3-δ)的制备及其电性能研究  

Preparation and electrical properties of the novel mixed ionic-electronic conductors Sm_(0.9)Ca_(0.1)Al_(1-x)Mn_xO_(3-δ)

作　　者：向军[1,2] 卫婷[1] 彭田贵[1] 张誉[1] 娄可行[1] 沈湘黔[2] 

机构地区：[1]江苏科技大学数理学院,镇江212003 [2]江苏大学材料科学与工程学院,镇江212013

出　　处：《物理学报》2009年第5期3402-3408,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50674048);江苏省高校自然科学研究计划项目(批准号:2008SL061J)资助的课题~~

摘　　要：采用有机凝胶法结合固相烧结技术制备了单相的Sm0.9Ca0.1Al1-xMnxO3-δ(SCAM,x=0.1—0.5)新型混合离子-电子导体.通过TG-DTA,XRD和直流四引线法研究了凝胶前驱体的热分解和相转化过程、烧结体的结构、相稳定性、导电性能及其电输运机理.结果表明,凝胶前驱体在900℃焙烧5h可以形成完全晶化的四方钙钛矿相纳米粉体,SCAM陶瓷样品在还原气氛下的相稳定性随Mn含量的升高而降低.经高温烧结制得的SCAM陶瓷的总电导率取决于p型电导,其值随Mn含量和温度的升高而增大,导电行为符合p型小极化子跳跃机理.随烧结温度的升高或保温时间的延长,SCAM9155的电导率和相对密度先增大后减小,1600℃烧结10h的SCAM9155样品具有最高的电导率和相对密度(98.2%),该样品在空气和5%H2/Ar气氛中850℃时的电导率分别为7.30和1.91S/cm,活化能分别为0.273和0.371eV.具有较高电导率的Ca,Mn掺杂的SmAlO3有望成为一种新型的SOFC阳极材料.The novel mixed ionic-electronic conductors Sin0.9 Ca0.1 Al1-x Mnx O3 （ SCAM, x = 0.1-0.5） were prepared by the organic gel method combined with solid state sintering technology. The thermal decomposition and phase inversion process of the gel precursors, crystal strucutres and phase stability of the sinters were studied by using thermogravimetric and differential thermal analysis （TG-DTA） and X-ray diffraction. The electrical conductivities of sintered ceramics in beth air and 5% H2/Ar were measured by the direct current four-wire method. The experimental results show that the well-crystallized nanopowders with tetragonal perovskite structure can be obtained after calcining the gel precursors at 900℃ for 5 h, the phase stability of SCAM ceramics decreases with increasing Mn content under reduction atmosphere. The electrical conductivity of SCAM ceramics is dominated by p-type electronic conduction and increases with Mn content and temperature. The mechanism of electronic transport is the hopping of p-type small polaron. With increasing calcination temperature and prolonging holding time, beth the electrical conductivity and relative density of SCAM9155 become large initially and then decrease. The SCAM9155 sample sintered at 1600 ℃ for 10h has the highest relative density of 98.2% and electrical conductivity reaching 7.30 S/cm in air and 1.91 S/cm in 5% H2/Ar at 850℃ . The apparent activation energies for SCAM9155 in air and in 5 % H2/Ar were calculated to be 0.273 and 0.371 eV, respectively. The Ca- and Mn-substituted SmAlO3 with relatively high conductivity may be used as a potential anode material for solid oxide full cells （SOFCs）.

关 键 词：混合离子-电子导体 SmAlO3 有机凝胶法 电导率 

分 类 号：TM911.4[电气工程—电力电子与电力传动]