Five element n-type thermoelectric material realizing powder alloy sintering phase transformation based on crystal topology and preparation method thereof

Abstract

The invention relates to a five element n-type thermoelectric material realizing powder alloy sintering phase transformation based on crystal topology and a preparation method thereof. The chemical formula of the n-type thermoelectric material is Bi<2-x-y>Sb<x>S<y>Te<3-z>Se<z>, wherein the x is greater than or equal to 0.74 and less than or equal to 1.2, y is greater than or equal to 0.04 and lessthan or equal to 0.06, z is greater than or equal to 0.2 and less than or equal to 0.45. Compared with other n-type thermoelectric materials, the five element n-type thermoelectric material disclosedby the invention undergoes the transformation of p-type alloy to p-type powder alloy embryo material to n-type thermoelectric material in the preparation process, therefore, the finally obtained fiveelement n-type thermoelectric material has the advantages of high Seebeck coefficient, high conductivity, low thermal conductivity, high ZT value and excellent thermoelectric performance.

Description

technical field [0001] The invention relates to the field of thermoelectric materials, in particular, to a five-element system n-type thermoelectric material and a preparation method for realizing powder alloy sintering phase transition based on crystal topology. Background technique [0002] A thermoelectric material is a functional material that uses the movement of carriers inside a solid to achieve direct mutual conversion of thermal energy and electrical energy. People's understanding of thermoelectric materials has a long history. As early as the early 19th century, the German Seebeck (Seebeck) discovered that the temperature difference between the two ends of the material can generate a voltage, which is commonly referred to as the thermoelectric phenomenon. Frenchman Peltier (Peltier) found that when a current flows, the temperature difference observed near the boundary of two different conductors is abnormal. These two phenomena show that heat can be converted int...

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Problems solved by technology

Although a higher Seebeck coefficient and a lower thermal conductivity can be obtained, they all increase the resistivity to varying degrees, resulting in a lower ZT value

In addition, the nano-micronization of materials and the preparation of thin-film materials require hydrothermal reaction / solvothermal reaction equipment, melt stripping equipment, electrochemical deposition, MOCVD or molecular beam epitaxy and other equipment, and subsequent vacuum hot-press sintering or discharge plasma (SPS ) sintering and other equipment require expensive equipment investment and operating costs, and cannot be continuously and stably mass-produced. Currently, they mainly exist in laboratories and scientific research fields, and have no practical and commercial value.

[0010] The reasons for the above shortcomings mainly include the following aspects: (1) The lattice of the ternary system thermoelectric material formed by doping is relatively complete and orderly, which cannot well reduce the lattice heat conduction of the material, and at the same time, the higher carrier Concentration and mobility also increase the contribution of carriers to thermal conductivity, which still cannot solve the problem of high thermal conductivity of materials; (2) The intrinsic excitation temperature of commercial ternary thermoelectric materials prepared by doping is low, resulting in The performance decays rapidly with the increase of temperature; (3), the Seebeck coefficient, resistivity and thermal conductivity have extremely complicated connections and influences, and the current technology suitable for large-scale commercial production (ie doping three elemental solid solution) it is difficult to better control the three

[0011] (2) The p-type material and n-type material of the thermoelectric chip have poor matching

However, the matching between the commonly used n-type materials and p-type materials is not good. Often, p-type materials have better thermoelectric properties, but the corresponding n-type materials have poor thermoelectric properties, which in turn affects the performance of thermoelectric chips.

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