Mg_(3)X_(2)(X=Sb,Bi)基热电材料的研究进展  

Advances in Mg_(3)X_(2)(X=Sb,Bi)-Based Thermoelectric Materials

作　　者：李秀宇 宋贵宏[1] 李贵鹏 刘莹[1] 胡方[1] Li Xiuyu;Song Guihong;Li Guipeng;Liu Ying;Hu Fang(School of Material Science and Technology,Shenyang University of Technology,Shenyang 110870,China)

机构地区：[1]沈阳工业大学材料科学与工程学院,辽宁沈阳110870

出　　处：《稀有金属》2022年第12期1621-1631,共11页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51772193)资助。

摘　　要：化石燃料产生的热能一部分以废热的形式流失到环境中。常常,废热的温度较低且低温废热占比很高,有效利用中低温废热将大大提高能源的利用率。热电材料器件能够实现热能与电能相互转换。Zintl相化合物因拥有“电子晶体-声子玻璃”的复杂晶体结构特征,具有优异的热电性能。Mg_(3)X_(2)(X=Sb,Bi)作为一种Mg基Zintl相化合物,具有成本低、组成元素储量丰富且热电性能优异等特点,被认为是一种极具应用潜力的中低温热电材料。近年来,关于如何提升Mg_(3)X_(2)的热电性能成为研究的热点。首先,综述了Mg_(3)X_(2)晶体结构的特点和其热电性能具有各向异性的特征,又分别综述了掺杂的Mg_(3)Sb_(2)和Mg_(3)Bi_(2)化合物的热电性能和最新研究进展。在相同温度下,n型Mg_(3)X_(2)比p型Mg_(3)X_(2)的热电性能更高。通过不等价n型或p型元素掺杂,大部分Mg_(3)X_(2)基材料虽然Seebeck系数值有所降低,但其电导率、功率因子和优值都增加,可有效改善Mg_(3)X_(2)基材料的热电性能。通过调整Mg_(3)(Sb,Bi)_(2)固溶体中Mg_(3)Bi_(2)的含量,可调整能带电子结构和带隙,在70%含量下(Mg_(3)Bi_(1.4)Sb_(0.6)合金)可获得最大的优值ZT。基于n型Mg_(3)Bi_(1.4)Sb_(0.6)合金在低温废热有效利用率已经超过现有的n型Bi_(2)Te_(3)合金,Mg_(3)X_(2)基很有可能在未来取代n型Bi_(2)Te_(3)合金,成为新的低温热电材料。A portion of the thermal energy generated by fossil fuels is released toward the environment in the form of waste heat.In general,low temperature waste heat is more.Effective use of medium and low temperature waste heat will greatly improve energy utilization rate.Thermoelectric material devices can directly carry out the mutual conversion of thermal energy and electrical energy,which possess these characteristics of simple devices,noiseless and environment friendly.Zintl phase compounds have excellent thermoelectric properties due to the complex crystal structure characteristics of"electronic crystal-phonon glass".Namely,they have the characteristics of high conductivity of crystal and low thermal conductivity of glass.Mg-based Zintl phase compound,such as Mg_(3)X_(2)(X=Sb,Bi)has the characteristics of low cost,abundant constituent elements,and excellent thermoelectric properties.It is widely studied as a potential medium and low temperature thermoelectric material.In recent years,it has been paid more attentions how to improve the thermoelectric performance of Mg_(3)X_(2)-based materials.In this paper,the characteristics of the crystal structure of Mg_(3)X_(2)and its anisotropic thermoelectric properties were first summarized.For single crystals,the electrical transport performance of Mg_(3)X_(2)material was anisotropic,and for polycrystalline Mg_(3)X_(2)material,the thermoelectric performance was isotropic.The thermoelectric performance greatly improved along texture direction for polycrystalline Mg_(3)X_(2)material after the texturing treatment in the optimum crystal orientation.Then the thermoelectric properties and the latest advances in the doped Mg_(3)Sb_(2)and Mg_(3)Bi_(2)compounds were introduced respectively.The references showed that n-type Mg_(3)X_(2)had higher thermoelectric figure of merit compared with p-type Mg_(3)X_(2)at the same temperature.It was related to band degeneracy of Nv=6 for n-type Mg_(3)X_(2)and Nv=1 for p-type Mg_(3)X_(2).The thermoelectric properties were poor for undoped p-type M

关 键 词：热电材料 Mg_(3)X_(2)(X=Sb Bi) Zintl相 SEEBECK系数 电导率 

分 类 号：TG147[一般工业技术—材料科学与工程]