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Facile synthesis of samarium and cerium doped double perovskite cobaltite with enhanced dielectric response
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作者 Yasir Abbas M.Kamran M.Anis-ur-Rehman 《Journal of Rare Earths》 SCIE EI CAS CSCD 2024年第7期1317-1327,I0005,共12页
The investigation of Sm-Ce doping on structure,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm_(x)CexCoO_(6)(x=0.000,0.025,0.050,0.075)(BCSCCO)are presented.All the specimens were synthesized by a facile synth... The investigation of Sm-Ce doping on structure,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm_(x)CexCoO_(6)(x=0.000,0.025,0.050,0.075)(BCSCCO)are presented.All the specimens were synthesized by a facile synthesis technique named the co-precipitation route.X-ray diffraction(XRD)reveals that BCSCCO crystallizes into one phase with space group P21/m.The crystallite size,dislocation density,lattice parameters,lattice strain,unit cell volume,and bulk density were determined using XRD data.The structural properties of Bi_(2)Ca_(2)CoO_(6)were examined using calculations based on the density functional theory.Theoretical and experimental values discrepancy is less than 1%.A scanning electron microscope was used for performing a microstructural analysis.The SEM images demonstrate the homogeneous distribution of grains with a range of sizes(0.054-0.090μm).The alternating current(ac)conductivity,dielectric permittivity,and tangent loss were also studied as a function of frequency(20 Hz-3 MHz)at different temperatures(100-500℃).All synthesized samples were examined using non-linear Debye's function to determine their spreading factor and relaxation time.The specimen with the lowest crystallite size(∼23 nm)exhibits a high dielectric permittivity(∼3.80×10^(6)).The conduction mechanism was examined in the studied samples with the use of Jonscher's power law.The power law indicates that the BCSCCO(x=0.000,0.025)follows correlated barrier hopping,whereas the x=0.050 and 0.075 compositions follow non-overlapping polaron tunneling.The studied specimen Bi_(2)Ca_(1.9)0Sm_(0.05)0Ce_(0.05)_(0)CoO_(6)with the highest density(∼5.65 g/cm^(3))displays a high electrical conductivity(∼46.1 S/cm).These findings correspond to those published for ceramics made from calcium cobaltite using solid-state reactions(5.0-26.0 S/cm). 展开更多
关键词 Bismuth calcium samarium cerium cobaltite (BCSCCO) Spreading factor Conduction mechanism Rare earths
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缓冲溶液法制备钴酸锶钐阴极材料及其性能 被引量:4
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作者 程继贵 石平 +2 位作者 仲洪海 王步美 孟广耀 《硅酸盐学报》 EI CAS CSCD 北大核心 2006年第2期255-260,共6页
以硝酸盐为前驱体,NH3·H2O-NH4HCO3为沉淀剂,用缓冲溶液法制得了Sm1-xSrCoO3复合沉淀物,将其在800~1000℃不同温度煅烧5h。用x射线衍射、透射电镜对煅烧产物的相组成和微观形貌进行了测定。所制备的(Sm1-xSr2CoO3)粉体模压... 以硝酸盐为前驱体,NH3·H2O-NH4HCO3为沉淀剂,用缓冲溶液法制得了Sm1-xSrCoO3复合沉淀物,将其在800~1000℃不同温度煅烧5h。用x射线衍射、透射电镜对煅烧产物的相组成和微观形貌进行了测定。所制备的(Sm1-xSr2CoO3)粉体模压成形后,在1000~1200℃进行烧结。用Archimedes排水法测定了烧结体的密度和孔隙率。用扫描电镜对烧结体的微观结构进行了观测。用直流四端子法测定了烧结样品的电导率。实验结果表明:缓冲溶液法所获得的沉淀物在800℃煅烧形成了具有钙钛矿结构的Sm1-xSrxCoO3粉体,其粒度均匀细小,形状规则。在一定的烧结温度,Sm1-xSrxCoO3烧结体具有多孔结构。随着烧结温度的增加,烧结体密度增大,孔隙率和孔径减小。Sr的掺入,使Sm1-xSrxCoO3烧结体的电导率明显高于未掺杂的SmCoO3。在500~800℃,Sm1-xSrxCoO3材料的电导率随温度的增高而降低。在500℃,样品Sm0.6Sro4CoO3的电导率可达2700S·cm^-1。 展开更多
关键词 缓冲溶液法 钴酸锶钐纳米粉体 孔隙率 电导率 阴极材料
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钐锶钴阴极/镧锶镓镁电解质界面的元素扩散
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作者 洪博 张云 +1 位作者 涂宝峰 程谟杰 《催化学报》 SCIE CAS CSCD 北大核心 2009年第9期919-925,共7页
采用X射线衍射、扫描电镜及电化学方法考察了固体氧化物燃料电池钐锶钴(Sm0.5Sr0.5CoO3-δ,SSC)阴极烧结温度和时间对镧锶镓镁(La0.9Sr0.1Ga0.8Mg0.2O3-δ,LSGM)电解质的导电行为和电解质/阴极界面电化学性质的影响.结果表明,当SSC阴极... 采用X射线衍射、扫描电镜及电化学方法考察了固体氧化物燃料电池钐锶钴(Sm0.5Sr0.5CoO3-δ,SSC)阴极烧结温度和时间对镧锶镓镁(La0.9Sr0.1Ga0.8Mg0.2O3-δ,LSGM)电解质的导电行为和电解质/阴极界面电化学性质的影响.结果表明,当SSC阴极的烧结温度由1173K升高到1323K时,LSGM/SSC界面形成了LaSrGaO4和LaSrGa3O7杂相;当烧结温度升高到1373K时,还形成了高电子电导率的La-Sr-Co-O复合化合物.Co元素的扩散导致LSGM电解质电子电导率升高,氧离子迁移数和电池开路电压降低.延长SSC阴极烧结时间,LSGM电解质的欧姆电阻增大,电解质氧离子迁移数和电池的开路电压降低,这是由于延长SSC烧结时间加剧了LSGM/SSC界面上高阻抗相LaSrGaO4和LaSrGa3O7的生成.阴极中大量Co元素的扩散改变了LSGM电解质内部组成与结构. 展开更多
关键词 固体氧化物燃料电池 镧锶镓镁 钐锶钴 电化学阻抗谱
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