Preparation method of n-type bismuth telluride-based thermoelectric material

Abstract

The invention discloses a preparation method of an n-type bismuth telluride-based thermoelectric material. The preparation method comprises the following steps: weighing bismuth powder, tellurium powder and selenium powder serving as raw materials according to the stoichiometric requirements of Bi2Te3-xSex, wherein x is more than or equal to 0.1 and less than or equal to 0.7; and then carrying outself-propagating reaction, reduction annealing, plasma activated sintering and hot forging treatment to obtain the compact n-type bismuth telluride-based thermoelectric material. The Bi2Te3-xSex powder is rapidly obtained by adopting a self-propagating combustion synthesis technology, reduction annealing is carried out on the Bi2Te3-xSex powder, and step-by-step hot forging is carried out to obtain the polycrystalline block thermoelectric material with high orientation, so that the thermoelectric performance of the obtained product can be remarkably improved; and the related preparation method is simple and convenient to operate, and a brand-new thought can be provided for expanded production of the high-performance n-type Bi2Te3-xSex-based thermoelectric material.

Description

technical field [0001] The invention belongs to the technical field of inorganic functional materials, and in particular relates to a preparation method of an n-type bismuth telluride-based thermoelectric material. Background technique [0002] Bismuth telluride-based thermoelectric materials are the only thermoelectric materials that have been commercially used so far. Among them, the p-type bismuth telluride system is developing rapidly, and the highest dimensionless thermoelectric figure of merit ZT can reach 1.96. However, the development of matching n-type materials is relatively lagging behind: single crystal n-type Bi prepared by zone melting method or pulling method 2 Te 3 Based on thermoelectric materials, the dimensionless thermoelectric figure of merit ZT has been around 0.9, which is difficult to be further improved. The maximum conversion efficiency and maximum cooling temperature difference of thermoelectric power generation devices and thermoelectric refrig...

AI Technical Summary

Problems solved by technology

However, the development of matching n-type materials is relatively lagging behind: single crystal n-type Bi prepared by zone melting method or pulling method 2 Te 3 Based thermoelectric materials, the dimensionless thermoelectric figure of merit ZT has been around 0.9, and it is difficult to further improve

The maximum conversion efficiency and maximum cooling temperature difference of thermoelectric power generation devices and thermoelectric cooling devices assembled with n-type and p-type materials prepared by zone melting method still have a large gap with the efficiency of conventional heat-burning engines and compressors

In addition, the zone melting method needs to give the sample a high temperature difference and a slow-moving growth rate, which causes the entire zone melting process to take a long time and consume a lot of energy.

At the same time, the high temperature difference also leads to greater stress inside the sample, requiring long-term high-temperature annealing to stabilize the sample composition and eliminate internal stress, which further leads to lower production efficiency and high energy consumption.

[0003] Although single crystal materials have the advantages of high electrical transport properties brought about by high orientation, their thermal transport properties and mechanical processing properties are relatively poor, which leads to the sample being easily damaged during cutting, which reduces the effective utilization rate of materials and also Increased costs, while the stability of long-term service is also restricted

Polycrystalline materials prepared by powder metallurgy usually require high-temperature melting and densification processes, which consume energy and time

Although the machinability is improved, the electrical transport performance is significantly reduced due to the disrupted texture

At the same time, due to the introduction of nanostructures and foreign doping elements, the thermal stability of long-term high-temperature service is also controversial

In addition, the precursor powder prepared by powder metallurgy is easily contaminated by the cavity, and the preparation process is cumbersome. The ball mill tank needs inert gas protection, and the ball mill process is time-consuming and energy-consuming; it is not conducive to large-scale industrial production.

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