K掺杂Ca3Co4O9的微波合成和热电性能研究  

Thermoelectric properties of K-doped Ca3Co4O9 prepared by microwave synthesis

作　　者：郭娟 张锦榜 郭倩 刘青松 郜超军 Guo Juan;Zhang Jinbang;Guo Qian;Liu Qingsong;Gao Chaojun(Key Laboratory of Material Physics of Ministry of Education,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]郑州大学物理工程学院,材料物理教育部重点实验室,郑州450001

出　　处：《河南师范大学学报（自然科学版）》2019年第4期42-49,共8页Journal of Henan Normal University(Natural Science Edition)

基　　金：国家自然科学基金(51302249)

摘　　要：以K2CO3,CaCO3和Co2O3为原料,利用微波方法合成了系列样品Ca3-xKxCo4O9(x≤0.30).随着K掺杂量的增加,晶格单斜应力在0≤x<0.10范围增加较快,而在0.10≤x≤0.30范围内变化不大.样品中空位型缺陷浓度随x先增加后减小,在x=0.10时,达到最大值.K掺杂样品的电导率随x增加而逐渐增加,Seebeck系数随x变化不大.样品的热导率在x=0.10时达到最低,其热电优值ZT也明显高于其他样品.在晶格应力、空位缺陷以及晶界三者的协同作用下,当T=873 K时,Ca2.90K0.10Co4O9的ZT可达到0.20.这一结果比溶胶凝胶法制备的样品ZT高约43%.The K-doped calcium cobalt oxides Ca3-xKxCo4O9(x≤0.30) have been synthesized by a microwave method from mixtures of K2CO3,CaCO3 and Co2O3. With the increase of x, the monoclinic strain of lattice firstly rises rapidly to 0≤x<0.10, then changes little to 0.10≤x≤0.30. The vacancy-type defect concentration in samples increases firstly and then decreases with increasing x, which reaches its maximum value as x=0.10. The conductivity of K-doped samples rises gradually with x. The K content has little effect on the Seebeck coefficient of samples. The thermal conductivity of sample with x=0.10 is the lowest among all samples. The thermoelectric figure of merit ZT value of this sample is higher than that of other samples. Benefiting from the synergetic effect of lattice strain, vacancy-type defect and grain boundary, the ZT value of sample Ca2.90K0.10Co4O9 is 0.20 at T=873 K, which is about 43% higher than that of sample prepared by sol-gel method.

关 键 词：钙钴氧化物 K掺杂 微波合成 热电性能 

分 类 号：O482[理学—固体物理]