Composite PbSe-based thermoelectric material doped with Sr and Na and preparation method thereof

Abstract

The invention discloses a composite PbSe-based thermoelectric material doped with Sr and Na and a preparation method thereof. The preparation method comprises the steps of firstly weighing Pb, Sr, Na and Se according to a stoichiometric ratio of Pb<0.98-x>Sr<x>Na<0.02>Se, mixing Pb, Sr, Na and Se, carrying out vacuum tube sealing smelting, and completing a phase formation stage of the phase. A sample after heat treatment is ground and put into a graphite die, and powder is manufactured into a block sample by adopting a rapid hot-pressing sintering technology, thereby being capable of acquiring a Pb<0.98-x>Sr<x>Na<0.02>Se thermoelectric material. Compared with traditional hot-pressing sintering, the preparation method disclosed by the invention has the advantages of uniform heating, high temperature rising speed, short sintering time and the like, and the sintered sample is obvious in performance variation. The thermal conductivity of the material is greatly reduced after being doped with Sr and Na, the Seebeck coefficient is increased, and a thermoelectric material with a high ZT value is acquired.

Description

technical field [0001] The invention relates to a functional composite material and a preparation method thereof, in particular to a PbSe-based thermoelectric composite material and a preparation method thereof, which are applied in the technical field of thermoelectric device material preparation. Background technique [0002] Thermoelectric material is a functional material that utilizes the movement of carriers inside a solid to realize direct mutual conversion of thermal energy and electrical energy. With the development of economy, people's demand for energy is getting higher and higher. Today, the world's energy structure is dominated by fossil energy. However, fossil energy as the main energy source is non-renewable energy. If you use a little, you will use a little less. However, due to the relationship between their own storage capacity and utilization rate, these energy sources cannot fully meet the needs of human production and life. The emergence of thermoelect...

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Problems solved by technology

[0007] Although thermoelectric devices made of thermoelectric materials have broad application prospects, the conversion efficiency of thermoelectric materials is very low, only about 10%, which is far lower than the 35% conversion efficiency of ordinary heat engines, which greatly limits the use of thermoelectric devices. application

However, theoretical calculations show that there is no upper limit to the ZT value of thermoelectric materials, and their energy conversion efficiency can be infinitely close to the Carnot cycle efficiency.

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