阅读说明：本技术 类金刚石结构热电材料及其制备方法 (Thermoelectric material with diamond-like structure and preparation method thereof ) 是由 杨波 于 2020-07-27 设计创作，主要内容包括：本申请涉及热电材料领域,公开了一种类金刚石结构热电材料及其制备方法所述类金刚石结构热电材料的化学式为Mn<Sub>2-x</Sub>Ag<Sub>x</Sub>Cu<Sub>3</Sub>In<Sub>3</Sub>Te<Sub>8</Sub>,其中(0＜x≤0.075)。本申请基于类金刚石结构热电材料Mn<Sub>2</Sub>Cu<Sub>3</Sub>In<Sub>3</Sub>Te<Sub>8</Sub>,优化了材料的热电性能,从本征热电优值(zT)从0.36提高到0.48,提高了33％。通过用Ag原子部分替代Mn原子,增加了化合物的载流子浓度,提高电性能的同时,也维持了化合物的低热导率。进一步为Mn<Sub>2</Sub>Cu<Sub>3</Sub>In<Sub>3</Sub>Te<Sub>8</Sub>与此类材料商用提供了新的方案。(The application relates to the field of thermoelectric materials, and discloses a thermoelectric material with a diamond-like structure and a preparation method thereof, wherein the chemical formula of the thermoelectric material with the diamond-like structure is Mn 2‑x Ag x Cu 3 In 3 Te 8 Wherein (x is more than 0 and less than or equal to 0.075). The thermoelectric material Mn based on diamond-like carbon structure 2 Cu 3 In 3 Te 8 The thermoelectric performance of the material is optimized, and the intrinsic thermoelectric figure of merit (zT) is improved from 0.36 to 0.48, which is improved by 33%. By partially replacing Mn atoms with Ag atoms, the carrier concentration of the compound is increased, the electrical property is improved, and meanwhile, the low thermal conductivity of the compound is maintained. Further is Mn 2 Cu 3 In 3 Te 8 Such materials offer new solutions for commercial use.)

1. A thermoelectric material with a diamond-like structure is characterized in that the chemical formula of the thermoelectric material with the diamond-like structure is Mn_2-xAg_xCu₃In₃Te₈Wherein (x is more than 0 and less than or equal to 0.075).

2. The diamond-like structure thermoelectric material according to claim 1, wherein x is 0.075.

3. The diamond-like structure thermoelectric material according to claim 1, wherein the thermal conductivity of the diamond-like structure thermoelectric material ranges from: 0.48W m^-1k^-1～2.15W*m^-1k^-1。

4. The thermoelectric material of any one of claims 1 to 3, wherein the zT value of the Geranite thermoelectric material is in the range of 0.36 to 0.48 at 823K.

5. The thermoelectric material of claim 4, wherein the zT value of the Geigranite thermoelectric material is in the range of 0.40 to 0.48 at 823K.

6. A method for preparing a thermoelectric material with a diamond-like structure, which is characterized by comprising the following steps:

(1) weighing elementary substances with the purity of more than 99.99 percent according to the stoichiometric ratio, mixing and packaging in a vacuum quartz tube;

(2) placing the vacuum quartz tube in a muffle furnace, preserving heat for 12-48 h in a molten liquid state at 850-950 ℃, then annealing for 48-96 h at 600-700 ℃, and cooling the furnace to room temperature to obtain an ingot;

(3) grinding the cast ingot into fine powder, and then placing the fine powder into a vacuum high-temperature high-pressure graphite grinding tool for hot pressing and blocking to prepare the thermoelectric material with the diamond-like structure, wherein the chemical formula of the thermoelectric material with the diamond-like structure is Mn_2-xAg_xCu₃In₃Te₈Wherein (x is more than 0 and less than or equal to 0.075).

7. The method of claim 6, wherein a oxyhydrogen high-temperature small-gas flame gun is used for sealing, and only the sealing portion is heat-sealed.

8. The method according to claim 6, wherein the heating rate of the vacuum quartz tube placed in the muffle furnace is 1-4 ℃/min.

9. The preparation method according to claim 6, wherein in the hot pressing process, the vacuum degree is lower than 5pa, the hot pressing pressure is 50-70MPa, the hot pressing temperature is 450-.

10. The production method according to any one of claims 6 to 9, wherein after the hot-pressed bulk material is annealed, the surface is taken out and polished, and then a thermoelectric property measurement is performed.

Technical Field

The application relates to the field of thermoelectric materials, and discloses a thermoelectric material with a diamond-like structure and a preparation method thereof.

Background

With the rapid development of global economic science and technology, the consumption of non-renewable fossil energy is exponentially increased. Scientists predict that global petroleum resources will be exhausted in 2050, other fossil energy will be exhausted in 2100 years at the latest, and development and utilization of new energy are imminent. In addition to solar energy, wind energy, water energy and the like, the huge energy stored in the heat energy also causes great enthusiasm of scientists, such as indoor and outdoor temperature difference, waste heat of factories, tail gas emission of automobiles and the like. The heat energy and electric energy conversion function of the thermoelectric material is the most effective way to realize the utilization of heat energy. The thermoelectric material realizes heat energy and electric energy conversion through microscopic current carriers, and realizes reliable and stable heat energy conversion without transmission parts, noise and pollution. The breakthrough of thermoelectric materials will be yet another milestone for new energy utilization.

Seebeck effect found by Seebeck, a German scientist, in 1821, and Pair effect, a reverse effect of Seebeck effect found by Peltier, a French scientist, in 1834, are two fundamental theories of thermoelectric materials. The seebeck effect is an effect that a temperature difference exists at two ends of a conductor to generate voltage, and the peltier effect is a phenomenon that a conductor electrified by the conductor generates temperature difference heat. Conversion efficiency is characterized by a thermoelectric figure of merit, zT ═ S²σ T/κ, wherein S is a Seebeck coefficient. σ is the electrical conductivity, T is the absolute temperature, and κ is the total thermal conductivity. Three physical parameters S Seebeck coefficient, electric conductivity sigma and thermal conductivity kappa which determine the thermoelectric figure of merit are mutually related, and the remarkable improvement of the thermoelectric figure of merit is difficult to realize by independently regulating and controlling one parameter, which is also the main reason that the zT value of few material systems breaks through 2 so far.

In the aspect of thermal transport performance, the complex quaternary crystal structure of the diamond-like thermoelectric material has strong phonon scattering, so that the lattice thermal conductance kL is only 0.36 at 823k, and the ultra-low thermal conductivity makes the diamond-like thermoelectric material a potential thermoelectric material. On the basis of low thermal conductivity, the current carrier concentration is improved and the electric conductivity is improved by doping Ag at the Mn site, and moreover, with the increase of Ag element, the phonon scattering of the compound is enhanced by the defects in the crystal, and meanwhile, the thermal conductivity is reduced, so that the zT is improved.

Disclosure of Invention

In view of the above problems, it is an object of the present application to provide a diamond-like structure thermoelectric material and a method for preparing the same.

Wherein the chemical formula of the thermoelectric material with the diamond-like structure is Mn_2-xAg_xCu₃In₃Te₈Wherein (x is more than 0 and less than or equal to 0.075).

Optionally, x is 0.075.

Optionally, the thermal conductivity range of the diamond-like structure thermoelectric material is: 0.48W m^-1k^-1～2.15W*m^-1k^-1。

Optionally, at 823K, the zT value of the digermite thermoelectric material is in a range of 0.36-0.48.

Optionally, at 823K, the zT value of the digermite thermoelectric material is in a range of 0.40-0.48.

The application also provides a preparation method of the thermoelectric material with the diamond-like structure, which comprises the following steps:

(1) weighing elementary substances with the purity of more than 99.99 percent according to the stoichiometric ratio, mixing and packaging in a vacuum quartz tube;

(2) placing the vacuum quartz tube in a muffle furnace, preserving heat for 12-48 h in a molten liquid state at 850-950 ℃, then annealing for 48-96 h at 600-700 ℃, and cooling the furnace to room temperature to obtain an ingot;

(3) grinding the cast ingot into fine powder, and then placing the fine powder into a vacuum high-temperature high-pressure graphite grinding tool for hot pressing and blocking to prepare the thermoelectric material with the diamond-like structure, wherein the chemical formula of the thermoelectric material with the diamond-like structure is Mn_2-xAg_xCu₃In₃Te₈Wherein (x is more than 0 and less than or equal to 0.075).

Optionally, during packaging, a hydrogen-oxygen high-temperature small-gas flame gun is adopted, and only the packaging part is heated and sealed.

Optionally, the heating rate of the vacuum quartz tube placed in the muffle furnace is 1-4 ℃/min.

Optionally, in the hot pressing process, the vacuum degree is lower than 5pa, the hot pressing pressure is 50-70Mpa, the hot pressing temperature is 450-600 ℃, and the high-temperature heat preservation and pressure maintaining time is 20-30 min.

Optionally, after annealing the hot-pressed bulk material, taking out and polishing the surface, and then performing thermoelectric performance measurement.

The thermoelectric material has a chemical formula of Mn_2-xAg_xCu₃In₃Te₈. Wherein x is more than 0 and less than 0.075, and the hole concentration is increased in the ultra-low lattice thermal conductive material by a non-equivalent doping method of doping Ag at the Mn position. After Ag atoms are doped, phonon scattering is enhanced due to the increase of defects in the crystal, so that the total thermal conductance is further reduced, and the purpose of improving the thermoelectric figure of merit (zT) is achieved. Preferably, (x ═ 0.075) has a high electrical conductivity and a low electrical conductivityThermal conductivity.

Preferably, the Seebeck of the diamond-like structure thermoelectric material is between 290uV/k and 340uV/k, and preferably between 325uV/k and 340 uV/k.

Drawings

The technical solutions of the embodiments of the present application are described in further detail below with reference to the accompanying drawings and embodiments.

FIG. 1 shows Mn prepared in example 1₂Cu₃In₃Te₈The temperature-dependent conductivity curve of (a);

FIG. 2 shows Mn prepared in example 1₂Cu₃In₃Te₈The seebeck versus temperature curve of (a);

FIG. 3 Mn prepared in example 1₂Cu₃In₃Te₈The total thermal conductance versus temperature curve;

FIG. 4 Mn prepared in example 1₂Cu₃In₃Te₈zT value versus temperature curve of (a);

FIG. 5 Mn prepared in example 2_1.95Ag_0.05Cu₃In₃Te₈The temperature-dependent conductivity curve of (a);

FIG. 6 Mn prepared in example 2_1.95Ag_0.05Cu₃In₃Te₈The seebeck versus temperature curve of (a);

FIG. 7 Mn prepared in example 2_1.95Ag_0.05Cu₃In₃Te₈The total thermal conductance versus temperature curve;

FIG. 8 Mn prepared in example 2_1.95Ag_0.05Cu₃In₃Te₈zT value versus temperature curve of (a);

FIG. 9 Mn prepared in example 1_1.925Ag_0.075Cu₃In₃Te₈The temperature-dependent conductivity curve of (a);

FIG. 10 Mn prepared in example 1_1.925Ag_0.075Cu₃In₃Te₈The seebeck versus temperature curve of (a);

FIG. 11 shows Mn prepared in example 1_1.925Ag_0.075Cu₃In₃Te₈The total thermal conductance versus temperature curve;

FIG. 12 Mn prepared in example 1_1.925Ag_0.075Cu₃In₃Te₈zT value of (a) versus temperature curve.

Detailed Description

The present application will be described in further detail with reference to the following examples, which are not intended to limit the scope of the present application.

The present application is directed to a diamond-like structure thermoelectric material and a method for preparing the same. In particular to a method for preparing a novel thermoelectric material with a P-type diamond-like structure and improving the electrothermal transport performance of the thermoelectric material.

Wherein the chemical formula of the thermoelectric material with the diamond-like structure is Mn_2-xAg_xCu₃In₃Te₈Wherein (x is more than 0 and less than or equal to 0.075).

Optionally, x is 0.075.

Optionally, the thermal conductivity range of the diamond-like structure thermoelectric material is: 0.48W m^-1k^-1～2.15W*m^-1k^-1。

Optionally, at 823K, the zT value of the digermite thermoelectric material is in a range of 0.36-0.48.

Optionally, at 823K, the zT value of the digermite thermoelectric material is in a range of 0.40-0.48.

The application also provides a preparation method of the thermoelectric material with the diamond-like structure, which comprises the following steps:

(1) weighing elementary substances with the purity of more than 99.99 percent according to the stoichiometric ratio, mixing and packaging in a vacuum quartz tube;

(2) placing the vacuum quartz tube in a muffle furnace, preserving heat for 12-48 h in a molten liquid state at 850-950 ℃, then annealing for 48-96 h at 600-700 ℃, and cooling the furnace to room temperature to obtain an ingot;

(3) grinding the cast ingot into fine powder, and then placing the fine powder into a vacuum high-temperature high-pressure graphite grinding tool for hot pressing and blocking to prepare the thermoelectric material with the diamond-like structureThe chemical formula of the thermoelectric material with the diamond-like structure is Mn_2-xAg_xCu₃In₃Te₈Wherein (x is more than 0 and less than or equal to 0.075).

Optionally, during packaging, a hydrogen-oxygen high-temperature small-gas flame gun is adopted, and only the packaging part is heated and sealed.

Optionally, the heating rate of the vacuum quartz tube placed in the muffle furnace is 1-4 ℃/min.

Optionally, in the hot pressing process, the vacuum degree is lower than 5pa, the hot pressing pressure is 50-70Mpa, the hot pressing temperature is 450-600 ℃, and the high-temperature heat preservation and pressure maintaining time is 20-30 min.

Optionally, after annealing the hot-pressed bulk material, taking out and polishing the surface, and then performing thermoelectric performance measurement.

The thermoelectric material has a chemical formula of Mn_2-xAg_xCu₃In₃Te₈. Wherein x is more than 0 and less than 0.075, and the hole concentration is increased in the ultra-low lattice thermal conductive material by a non-equivalent doping method of doping Ag at the Mn position. After Ag atoms are doped, phonon scattering is enhanced due to the increase of defects in the crystal, so that the total thermal conductance is further reduced, and the purpose of improving the thermoelectric figure of merit (zT) is achieved. Preferably, (x ═ 0.075) has a high electrical conductivity and a low thermal conductivity.

Preferably, the Seebeck of the diamond-like structure thermoelectric material is between 290uV/k and 340uV/k, and preferably between 325uV/k and 340 uV/k.

Next, the concrete preparation and examples will be explained.