中国有色金属学报
ZHONGGUO YOUSEJINSHU XUEBAO
第18卷 第11期 总第116期 2008年11月 |
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文章编号:1004-0609(2008)11-2056-06
高度织构Ni掺杂NaxCoO2氧化物的制备及其热电性能
王 蕾,王 鸣,赵栋梁
(钢铁研究总院 功能材料研究所,北京 100081)
摘 要: 采用CAC法制备具有高度结晶各向异性的Ni掺杂NaxCoO2热电氧化物。X射线衍射和场发射扫描电子显微镜测试显示样品内层状晶粒的c轴沿着施压方向取向排列,形成高度织构。Ni的掺杂使得样品晶粒尺寸明显减小。热电性质的测试表明:Ni的掺杂虽然提高声子散射,降低热导率值,但同时也加大载流子散射,提高电阻率。Seebeck系数有明显提高,最大值达到154 μV/K,显示NaxCoO2氧化物热电材料采用Co位掺杂改进性能的发展潜力。
关键字: NaxCoO2;热电性能;掺杂;Seebeck系数
Thermoelectric properties of highly textured Ni-substituted NaxCoO2 ceramics
WANG Lei, WANG Ming, ZHAO Dong-liang
(Functional Materials Research Institute, Central Iron and Steel Research Institute, Beijing 100081, China)
Abstract:Ni-substituted NaxCoO2 thermoelectric oxide ceramics with high crystallographic anisotropy were synthesized successfully by citric acid complex (CAC) process. The results of XRD, FE-SEM measurements and thermoelectric properties show that c-axis of layered grain within the sample aligns along the pressing direction and the sample is highly textured. With Ni substitution, the grain size obviously decreases. Ni substitution results in lower thermal conductivity and higher electrical resistivity. On the other hand, Ni substitution leads to the significant increase of Seebeck coefficient, and the maximum value reaches 154 μV/K. The experimental results indicate that the substitution of Co-sites can improve the thermoelectric properties of NaxCoO2.
Key words: NaxCoO2; thermoelectric properties; substitution; Seebeck coefficient