Preparation method of single-crystal Bi2Te3 thermoelectric material

Abstract

The invention provides a preparation method of a single-crystal Bi2Te3 thermoelectric material and belongs to the technical field of energy source materials. The preparation method comprises the following steps: taking Bi2Te3 powder which is pre-synthesized through a mechanical alloying method as a raw material, keeping pressure under 2MPa for 0.5 to 1.5min in batches and pressing the raw materials into sheets; putting the sheets into a sharp-bottom quartz tube and sealing the tube in vacuum; then putting the quartz tube into a vertical furnace in a manner of putting the sharp bottom of the quartz tube downward; raising the temperature to 600 to 750 DEG C at the speed of 5 to 30 DEG C / h and carrying out heat insulation for 10 to 30h; then slowly cooling to 380 to 550 DEG C at the speed of1 to 3 DEG C / h; then cooling to 30 DEG C at the speed of 10 to 50 DEG C / h, so as to obtain a single-crystal Bi2Te3 block body. The single-crystal Bi2Te3 block body thermoelectric material has an in-plane power factor of 2 to 5mWm<-1>K<-2> and an inter-plane power factor of 0.6 to 2mWm<-1>K<-2>. The mechanical alloying method and a temperature gradient curing method are combined to prepare the single-crystal Bi2Te3 block body thermoelectric material; the preparation method has the characteristics of simple process, simplicity in operation, low requirements on equipment and a preparation environment, low sintering temperature and the like, and the thermoelectric performance of a Bi2Te3 block body is improved. The prepared single-crystal Bi2Te3 thermoelectric material can be widely applied inthe fields of temperature difference power generation, thermoelectric refrigeration and the like.

Description

technical field [0001] The invention belongs to the technical field of energy materials, in particular to a single crystal Bi 2 Te 3 Preparation methods of thermoelectric materials. Background technique [0002] Thermoelectric materials can realize mutual conversion of thermal energy and electrical energy through Seebeck effect and Peltier effect, and realize thermoelectric power generation and thermoelectric refrigeration. Thermoelectric devices composed of N-type and P-type thermoelectric materials have the advantages of small size, no noise, no moving parts, no pollution, high reliability and long life. They are used in industrial waste heat utilization, fluorine-free refrigeration, aerospace, high-performance reception It has broad application prospects in the fields of devices and sensors. The thermoelectric properties of materials can be measured by the dimensionless thermoelectric figure of merit ZT = α 2 σT / κ, where α is the Seebeck coefficient, σ is the electric...

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Problems solved by technology

[0004] So far, polycrystalline Bi has been pre-synthesized by mechanical alloying 2 Te 3 Powder, combined with the temperature gradient solidification method described in the present invention at 600-750 ° C to prepare single crystal Bi with good crystallinity and compact structure 2 Te 3 Bulk thermoelectric materials have not been reported

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