新钴基层状化合物AxCoO2的制备与热电性能研究

项目名称： 新钴基层状化合物AxCoO2的制备与热电性能研究

项目编号： No.51302291

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 刘锦峰

作者单位： 中国科学院上海硅酸盐研究所

项目金额： 24万元

中文摘要： 氧化物热电材料是热电材料高温应用中十分重要的候选材料，作为氧化物热电材料杰出代表的NaxCoO2，虽然具有优异的热电性能，但是由于含有钠而存在易潮解以及高温时钠易挥发等缺点，极大地影响了其推广和应用。大量研究表明，含有具有CdI2型晶体结构的CoO2亚层以及层状交替结构是这类钴基层状化合物具有优异热电性能的关键因素。本研究拟利用NaxCoO2能与其它阳离子盐发生离子交换反应生成新的化合物AxCoO2，而本身结构只进行局部调整即仍含有CoO2亚层且仍具有层状交替结构这一特点，结合本人前期关于离子替代产物CaxCoO2和SrxCoO2的研究结果，选择比Sr2+半径大的二价阳离子如Ba2+和Pb2+等的硝酸盐与NaxCoO2进行离子交换反应，制备新的钴基层状化合物AxCoO2，并对其热电性能进行研究，最终开发出一至两种性能优异且可靠性高的氧化物热电材料，为热电材料的高温应用提供新的重要候选材料。

中文关键词： 热电；钴基层状化合物；离子交换反应；BaxCoO2；PbxCoO2

英文摘要： Oxide thermoelectric materials are the promising candidates for thermoelectric materials application at high temperatures. Layered cobaltites NaxCoO2 was discovered to exhibit good thermoelectric properties such as a large Seebeck coefficient and a low resistivity and thermal conductivity. However, the deliquescence and high vapor pressure of sodium make it not very suitable to be used for thermoelectric devices. It's reported that CoO2 layers with the CdI2 type as well as the alternately layered structure play a very important role in the thermoelectric properties of the layered cobaltites. As a result, in this study, we try to synthesize new layered cobaltites AxCoO2 with the same structure of NaxCoO2 by the ion exchange technique from NaxCoO2 precursor, because layered cobaltites NaxCoO2 has a remarkable property, which is that the sodium ions between the CoO2 layers can be exchanged with the other cation ions. According to the results of my study about the ion exchange resultants CaxCoO2 and SrxCoO2, we will choose some cation ions such as Ba2+ and Pb2+ with the radius larger than Sr2+ to react with NaxCoO2, and prepare novel layered cobaltites AxCoO2 by the ion exchange technique, and try to search for one or two new layered cobaltites with good thermoelectric properties and high reliability for high temper

英文关键词： thermoelectric；layered cobaltites；ion exchange technique；BaxCoO2；PbxCoO2