阅读说明：本技术 一种N型TiS2基热电材料及其制备方法 (N-type TiS 2-based thermoelectric material and preparation method thereof ) 是由 朱华锋 马志乐 于 2020-03-30 设计创作，主要内容包括：本发明公开了一种N型TiS2基热电材料及其制备方法,本发明的方法包括先制备TiS2粉末,再将InSb纳米粉末通过行星式球磨的方法与TiS2粉末充分混合,最后通过热压烧结制备得到热电材料,通过调节复合物热电材料中各组分的百分含量,并结合调控各个工序中的参数,实现了TiS2和InSb的有效复合。通过该方法优化了N型TiS2基热电材料的低温性能,特别是降低了热导率、提高了功率因子和ZT值。本发明与现有的技术相比的优点在于：本发明的方法具有原料丰富、价格优廉、环境友好、工艺简便、易于规模规模化生产和实用性强。(The invention discloses an N-type TiS 2-based thermoelectric material and a preparation method thereof, the method comprises the steps of firstly preparing TiS2 powder, then fully mixing InSb nano powder with TiS2 powder by a planetary ball milling method, finally preparing the thermoelectric material by hot-pressing sintering, and realizing the effective compounding of TiS2 and InSb by adjusting the percentage content of each component in the compound thermoelectric material and combining and regulating parameters in each process. The method optimizes the low-temperature performance of the N-type TiS 2-based thermoelectric material, particularly reduces the thermal conductivity and improves the power factor and ZT value. Compared with the prior art, the invention has the advantages that: the method has the advantages of rich raw materials, low price, environmental friendliness, simple and convenient process, easy large-scale production and strong practicability.)

1. An N-type TiS 2-based thermoelectric material, which is characterized in that: the N-type TiS 2-based thermoelectric material contains a TiS2 matrix and InSb, the total mass of the N-type TiS 2-based thermoelectric material is 100%, wherein the mass fraction of the InSb is 0-20% and is not 0%, the mass fraction of the TiS2 matrix is 80-100% and is not 100%, the mass fraction of the InSb is 2.5-15%, and the mass fraction of the TiS2 matrix is 85-97.5%.

2. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 1, wherein the method comprises the following steps: the method comprises the following steps:

(1) preparing TiS2 powder;

(2) uniformly mixing the nano InSb powder with the TiS2 powder prepared in the step (1) to obtain mixed powder, and carrying out nano treatment on the mixed powder by a mechanical alloying method to obtain nano composite powder;

(3) and (3) carrying out hot-pressing sintering on the nano composite powder obtained in the step (2) to obtain the N-type TiS 2-based thermoelectric material.

3. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 2, wherein the method comprises the following steps: the method for preparing TiS2 powder in step (1) is as follows: mixing the Ti simple substance and the S simple substance according to the molar ratio of 1:2, sealing the mixed powder into a vacuum quartz tube, putting the vacuum quartz tube into a tube furnace for smelting, and grinding the smelted product to obtain TiS2 powder.

4. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 3, wherein the method comprises the following steps: the purity of the Ti simple substance and the purity of the S simple substance are both more than 99.9 percent, and the Ti simple substance and the S simple substance are powdery raw materials.

5. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 3 or 4, wherein: in the method for preparing the TiS2 powder in the step (1), the smelting temperature is 500-800 ℃, in the method for preparing the TiS2 powder in the step (1), the heating rate of heating to the smelting temperature is 1-10 ℃/min, in the method for preparing the TiS2 powder in the step (1), the smelting time is 72-240 h, and in the method for preparing the TiS2 powder in the step (1), the grinding time is 1-5 h.

6. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 5, wherein the method comprises the following steps: the smelting temperature is 660 ℃, the temperature rise rate of the smelting temperature is 5 ℃/min, and the smelting time is 168 h.

7. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 2, wherein the method comprises the following steps: the purity of the InSb powder in the step (2) is more than 99.9 percent, the mechanical alloying method in the step (2) is planetary ball milling, and the ball milling time of the planetary ball milling is 1-100 h.

8. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 7, wherein the method comprises the following steps: the device adopted by the planetary ball milling is a four-station planetary ball mill, and the ball milling time of the planetary ball mill is 10-40 h.

9. The method for preparing the N-type TiS 2-based thermoelectric material as claimed in claim 2, wherein the method comprises the following steps: the sintering method in the step (3) is a hot-pressing sintering method, the sintering temperature in the sintering process in the step (3) is 200-500 ℃, the heating rate in the sintering temperature process is 2-15 ℃/min, the sintering time is 30-120 min, the sintering vacuum degree is 1-5 Pa, and the sintering pressure is 100-600 MPa.

10. The method for removing the N-type TiS 2-based thermoelectric material as claimed in claim 9, wherein the method comprises the following steps: in the step (3), the sintering temperature in the sintering process is 300 ℃, the heating rate in the sintering temperature process is 5 ℃/min, the sintering time is 60min, and the sintering pressure is 300 MPa.

Technical Field

The invention relates to the technical field of thermoelectric materials, in particular to an N-type TiS 2-based thermoelectric material and a preparation method thereof.

Background

The thermoelectric device for thermoelectric power generation can directly convert heat energy into electric energy without moving parts and working media, does not discharge any toxic and harmful substances and greenhouse gases, and is a typical green energy technology. The device can utilize geothermal heat and a large amount of waste heat discharged by power plants, boilers and the like to generate power, thereby saving a large amount of energy. When the waste heat discharged by the automobile is used for generating electricity, the waste heat can be recycled, a large amount of energy can be saved, and the environmental pollution can be reduced.

The key core of the thermoelectric device is the thermoelectric material for manufacturing the device, and the achievement of the thermoelectric material with high performance is the premise for developing the high-efficiency thermoelectric device. The performance of a thermoelectric material is characterized by a dimensionless parameter, ZT, where T is the absolute temperature and Z is called the thermoelectric figure of merit (figure of merit) which is related to the physical performance parameter of the material by:

ZT＝S2σT/κ

in the formula, σ is electric conductivity, S is thermoelectric potential (Seebeck coefficient), and κ ═ κ c + κ L (κ c is thermal conductance contributed by carriers, and κ L is thermal conductance of crystal lattices or phonons) is total thermal conductivity of the material.

Therefore, the search for new thermoelectric materials that effectively improve ZT values has been a research goal in the field of thermoelectric technology.

TiS2 has been widely studied as an electrode material of a lithium ion battery, and has been found to have important research value as a low-temperature thermoelectric material with great potential in recent years, for example, Guilmeau et al have studied the high-temperature thermoelectric performance of Cu-doped TiS2 (appl.Phys. L ett.111, 133903(2017)), and Zhou et al have also obtained higher thermoelectric performance in a TiS2 matrix film material, and the power factor PF-2.167 muW/cm. K2(ACS appl.Mater. interfacial 9,49, 42430-42437 (2017)) has obtained less research on the low-temperature performance of a bulk TiS2 thermoelectric material, so a key technology is urgently needed to improve the low-temperature thermoelectric performance of the material system.

Disclosure of Invention

The invention aims to overcome the technical defects and provides an N-type TiS 2-based thermoelectric material and a preparation method thereof.

In order to solve the problems, the technical scheme of the invention is as follows: an N-type TiS 2-based thermoelectric material comprises a TiS2 matrix and InSb, wherein the total mass of the N-type TiS 2-based thermoelectric material is 100%, the mass fraction of the InSb is 0-20% and does not contain 0%, the mass fraction of the TiS2 matrix is 80-100% and does not contain 100%, the mass fraction of the InSb is 2.5-15%, and the mass fraction of the TiS2 matrix is 85-97.5%.

A preparation method of an N-type TiS 2-based thermoelectric material comprises the following steps:

(1) preparing TiS2 powder;

(2) uniformly mixing the nano InSb powder with the TiS2 powder prepared in the step (1) to obtain mixed powder, and carrying out nano treatment on the mixed powder by a mechanical alloying method to obtain nano composite powder;

(3) and (3) carrying out hot-pressing sintering on the nano composite powder obtained in the step (2) to obtain the N-type TiS 2-based thermoelectric material.

As a modification, the method for preparing TiS2 powder in step (1) is as follows: mixing the Ti simple substance and the S simple substance according to the molar ratio of 1:2, sealing the mixed powder into a vacuum quartz tube, putting the vacuum quartz tube into a tube furnace for smelting, and grinding the smelted product to obtain TiS2 powder.

As an improvement, the purities of the Ti simple substance and the S simple substance are both more than 99.9%, and the Ti simple substance and the S simple substance are powdery raw materials.

As an improvement, in the method for preparing the TiS2 powder in the step (1), the smelting temperature is 500-800 ℃, in the method for preparing the TiS2 powder in the step (1), the heating rate of heating to the smelting temperature is 1-10 ℃/min, in the method for preparing the TiS2 powder in the step (1), the smelting time is 72-240 h, and in the method for preparing the TiS2 powder in the step (1), the grinding time is 1-5 h.

As an improvement, the smelting temperature is 660 ℃, the temperature rise rate of the smelting temperature is 5 ℃/min, and the smelting time is 168 h.

As an improvement, the purity of the InSb powder in the step (2) is more than 99.9 percent, the mechanical alloying method in the step (2) is planetary ball milling, and the ball milling time of the planetary ball milling is 1-100 h.

As an improvement, the device adopted by the planetary ball milling is a four-station planetary ball mill, and the ball milling time of the planetary ball milling is 10-40 h.

As an improvement, the sintering method in the step (3) is a hot-pressing sintering method, the sintering temperature in the sintering process of the step (3) is 200-500 ℃, the heating rate in the sintering temperature process is 2-15 ℃/min, the sintering time is 30-120 min, the sintering vacuum degree is 1-5 Pa, and the sintering pressure is 100-600 MPa.

As an improvement, in the step (3), the sintering temperature in the sintering process is 300 ℃, the heating rate in the sintering temperature process is 5 ℃/min, the sintering time is 60min, and the sintering pressure is 300 MPa.

Compared with the prior art, the invention has the advantages that:

(1) according to the method, the TiS2 powder is prepared, mixed with the InSb powder, and subjected to nanocrystallization through mechanical alloying, the nanocrystallized composite powder is sintered, parameter control in each process and the addition amount of InSb are adjusted, effective compounding of TiS2 and InSb is realized, and the N-type TiS 2-based thermoelectric material with excellent performance is prepared.

(2) The N-type TiS 2-based composite thermoelectric material has low thermal conductivity, high thermoelectromotive rate (Seebeck coefficient), high power factor PF and thermoelectricity figure of merit ZT value, the lattice thermal conductivity is reduced by 60 percent near room temperature, the lattice thermal conductivity reaches 1.28W/m.K, the power factor PF is increased by 2.9 times, the lattice thermal conductivity reaches 31.20 mu W/cm.K 2, the thermal property and the electrical property are optimized, the thermal property and the electrical property are excellent, and the application prospect is wide.

Drawings

FIG. 1 is a graph comparing the change curve of the electrical conductivity with the temperature of an N-type TiS 2-based thermoelectric material prepared in examples 1-5.

FIG. 2 is a graph comparing the thermoelectric voltage variation with temperature of an N-type TiS 2-based thermoelectric material prepared in examples 1-5.

FIG. 3 is a graph comparing the thermal conductivity of an N-type TiS 2-based thermoelectric material prepared in examples 1-5 with the temperature variation curve.

FIG. 4 is a graph comparing thermoelectric figure of merit ZT versus temperature curves of N-type TiS 2-based thermoelectric materials prepared in examples 1-5.

FIG. 5 is a graph comparing thermoelectric figure of merit ZT of the N-type TiS 2-based thermoelectric materials prepared in examples 1-5 with temperature.

Detailed Description

The present invention is further described below by way of specific examples, but the present invention is not limited to only the following examples. Variations, combinations, or substitutions of the invention, which are within the scope of the invention or the spirit, scope of the invention, will be apparent to those of skill in the art and are within the scope of the invention.

An N-type TiS 2-based thermoelectric material and a preparation method thereof, wherein the N-type TiS 2-based thermoelectric material contains a TiS2 matrix and InSb, the total mass of the N-type TiS 2-based thermoelectric material is 100%, wherein the mass fraction of the InSb is 0% -20% and is not 0%, the mass fraction of the TiS2 matrix is 80% -100% and is not 100%, the mass fraction of the InSb is 2.5% -15%, and the mass fraction of the TiS2 matrix is 85% -97.5%.

A preparation method of an N-type TiS 2-based thermoelectric material comprises the following steps:

(1) preparing TiS2 powder;

(2) uniformly mixing the nano InSb powder with the TiS2 powder prepared in the step (1) to obtain mixed powder, and carrying out nano treatment on the mixed powder by a mechanical alloying method to obtain nano composite powder;

(3) and (3) carrying out hot-pressing sintering on the nano composite powder obtained in the step (2) to obtain the N-type TiS 2-based thermoelectric material.

The method for preparing TiS2 powder in step (1) is as follows: mixing the Ti simple substance and the S simple substance according to the molar ratio of 1:2, sealing the mixed powder into a vacuum quartz tube, putting the vacuum quartz tube into a tube furnace for smelting, and grinding the smelted product to obtain TiS2 powder.

The mass fraction of InSb in a particular embodiment may be determined by requirements such as: 0.5%, 1%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 7.5%, 8%, 9%, 10%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or the like.

The purity of the Ti simple substance and the purity of the S simple substance are both more than 99.9 percent, and the Ti simple substance and the S simple substance are powdery raw materials.

In the method for preparing the TiS2 powder in the step (1), the smelting temperature is 500-800 ℃, in the method for preparing the TiS2 powder in the step (1), the heating rate of heating to the smelting temperature is 1-10 ℃/min, in the method for preparing the TiS2 powder in the step (1), the smelting time is 72-240 h, and in the method for preparing the TiS2 powder in the step (1), the grinding time is 1-5 h.

In the method for preparing TiS2 powder in the step (1) in the specific embodiment, the melting temperature may be 500 ℃, 540 ℃, 580 ℃, 620 ℃, 660 ℃, 700 ℃, 740 ℃, 780 ℃, or 800 ℃ or the like, and 660 ℃ is adopted in this embodiment.

In the method for preparing TiS2 powder in step (1) above in the specific embodiment, the heating rate of heating to the melting temperature may be 1 ℃/min, 2 ℃/min, 3 ℃/min, 4 ℃/min, 5 ℃/min, 6 ℃/min, 7 ℃/min, 8 ℃/min, 9 ℃/min or 10 ℃/min, etc., and the preferred scheme adopted in this embodiment is 5 ℃/min.

In the method for preparing TiS2 powder in the step (1) in the specific embodiment, the smelting time may be 72h, 84h, 96h, 108h, 120h, 132h, 144h, 156h, 168h, 180h, 192h, 204h, 216h, 228h or 240h, etc., and the preferred scheme adopted in this embodiment is 168 h.

In the method for preparing TiS2 powder described in the above step (1), the milling time may be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, or the like.

The purity of the InSb powder in the step (2) is more than 99.9 percent, the mechanical alloying method in the step (2) is planetary ball milling, and the ball milling time of the planetary ball milling is 1-100 h.

The device adopted by the planetary ball milling is a four-station planetary ball mill, and the ball milling time of the planetary ball mill is 10-40 h.

In specific embodiments, the ball milling time of the planetary ball mill may be 1h, 1.5h, 2h, 2.5h, 3h, 4h, 4.5h, 5.5h, 6.5h, 8h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 70h, 75h, 80h, 90h or 100h, etc., and preferably ranges from 10h to 40 h.

The sintering method in the step (3) is a hot-pressing sintering method, the sintering temperature in the sintering process in the step (3) is 200-500 ℃, the heating rate in the sintering temperature process is 2-15 ℃/min, the sintering time is 30-120 min, the sintering vacuum degree is 1-5 Pa, and the sintering pressure is 100-600 MPa.

In the sintering process in the step (3) in the specific embodiment, the sintering temperature may be 200 ℃, 220 ℃, 230 ℃, 250 ℃, 265 ℃, 275 ℃, 285 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃, 410 ℃, 420 ℃, 430 ℃, 440 ℃, 450 ℃, 460 ℃, 470 ℃, 480 ℃, 490 ℃ or 500 ℃ or the like, preferably the range is 250 ℃ to 360 ℃, more preferably 300 ℃, and when the sintering temperature is lower than 250 ℃, the obtained product has low density and poor thermoelectric performance; when the sintering temperature is higher than 500 ℃, TiS2 can be softened, the preparation of the sample is affected, and the preparation of the sample is even failed.

In the specific embodiment, in the sintering process in the step (3), the heating rate of heating to the sintering temperature is2 ℃/min, 4 ℃/min, 6 ℃/min, 8 ℃/min, 10 ℃/min, 11 ℃/min, 12.5 ℃/min, 14.5 ℃/min or 15 ℃/min, and the like, and in the embodiment, the preferred scheme is 5 ℃/min.

In the sintering process in the step (3) in the specific embodiment, the sintering time may be 30min, 40min, 50min, 60min, 70min, 85min, 100min, 110min, or 120min, and the preferred scheme in this embodiment is 60 min.

In the sintering process in the step (3), the vacuum degree of sintering may be 1Pa, 1.5Pa, 2Pa, 3Pa, 4Pa, 4.5Pa, 5Pa, or the like.

In the specific embodiment, in the sintering process in the step (3), the sintering pressure may be 100MPa, 150MPa, 180MPa, 195MPa, 200MPa, 250MPa, 300MPa, 350MPa, 400MPa, 450MPa, 500MPa, 600MPa, or the like, and in the embodiment, 300MPa is used as a preferred embodiment.