石墨烯复合β-Zn4Sb3材料的热电性质

Investigation on the thermoelectric properties of β-Zn4Sb3/graphene composites

将不同比例的石墨烯粉末和β-Zn4 Sb3粉末混合,通过热压法制备出复合材料样品,并对其结构和热电性质进行检测.X射线衍射结果表明,样品的主要成分仍然是β-Zn4 Sb3相,晶粒尺寸随石墨烯浓度的增加略有减小.这说明石墨烯浓度在5.0%以内时对样品的物相形成没有明显影响.另外,复合石墨烯后样品的Seebeck系数变化不大,但电导率降低、热导率略有增大,从而使热电优值有所降低,主要是由于石墨烯的掺入在样品中引入了电子补偿效应,使原来受主能级上的空穴减少,进而降低了样品中的载流子浓度,同时也改变了β-Zn4 Sb3中Zn原子无序结构.

β-Zn4Sb3/graphene composite material was prepared by mixing graphene powder and β-Zn4Sb3 powder through hot pressing,and its structure and thermoelectric properties were checked.The results of X-ray diffraction show that the main component of the composite samples is still β-Zn4Sb3 phase,and that the average grain size decreases slightly with the increase of graphene concentration,indicating that there is no significant effect on the phase formation of the composite sample when the graphene concentration is within 5.0%.In addition,the Seebeck coefficient of the composites containing graphene varies only slightly,but the electrical conductivity decreases and the thermal conductivity increases,which contributes to the lowering of the ZT value.The main reason might be the reduction of hole concentration due to the electron compensation effect accompanied by the incorporation of graphene,thereby reducing the sample carrier concentration,and the changes to the Zn atom disorder of β-Zn4Sb3 as well.