A non-layered low thermal conductivity indium selenide-based material and its preparation method and application

Abstract

The present invention relates to a non-layered low thermal conductivity indium selenide-based material, the chemical formula of which is In x Se y X z , wherein X is any one of I, Te, and La, x=1 or x=1-z, y=1 or y=1-z, and z=0.01-0.1. The method for preparing a non-layered low-thermal-conductivity indium selenide-based material provided by the present invention has abundant raw material sources, low cost, simple production process and production equipment, and good controllability and repeatability. The non-layered low-thermal-conductivity indium selenide-based material can be directly obtained by dry-milling and wet-milling the initial raw materials to obtain a powder, which is then dried and sintered without the need for steps such as melting, thereby streamlining and optimizing the preparation steps and process and saving costs.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoelectric materials, and in particular to a non-layered low thermal conductivity indium selenide-based material, a preparation method thereof, and applications thereof. Background Art

[0002] Exploring the structure and properties of new prototypes is of great interest and significance to several disciplines including materials science, chemistry and physics. Indium selenide (InSe) is a complex III-VIA semiconductor compound that usually adopts a two-dimensional (2D) layered structure, mainly including hexagonal β phase (space group P63 / mmc), ε phase (space group P Layered indium selenide has a rich variety of electrical, optical, thermal, and mechanical properties, including high carrier mobility, good chemical stability, and robust charge transfer capabilities, and can be used in transistors, thermoelectric devices, and nonlinear optical devices.

[0003] In addition, there are some unusual metastable phases in the pressure-temperature phase diagram, such as the monoclinic structure (space group P2 / m). For a long time, this phase structure could only be synthesized by pressure-induced γ-InSe phase transition under high pressures of several gigapascals. The synthesis conditions were harsh and resource-intensive. Summary of the Invention

[0004] In response to the defects in the prior art, the purpose of the present invention is to provide a non-layered low thermal conductivity indium selenide-based material and its preparation method and application. An indium selenide-based material with a monoclinic crystal structure can be obtained through simple preparation steps and processes. The obtained material has a low thermal conductivity and can be used as a thermal insulation material, a heat insulating material and a thermoelectric energy conversion material.

[0005] The first aspect of the present invention provides a non-layered low thermal conductivity indium selenide-based material, the chemical formula of which is In x Se y X z , where X is any element among I, Te, and La, x=1 or x=1-z, y=1 or y=1-z, and z=0.01~0.1.

[0006] Optionally, the non-layered low thermal conductivity indium selenide-based material has a monoclinic crystal structure.

[0007] A second aspect of the present invention provides a method for preparing the above-mentioned non-layered low thermal conductivity indium selenide-based material, comprising the following steps:

[0008] According to the chemical formula of non-layered low thermal conductivity indium selenide x Se y X zWeigh In solid powder, Se solid powder, and solid powder containing element X in a stoichiometric ratio, wherein X is any one of I, Te, and La;

[0009] The weighed In solid powder, Se solid powder, and solid powder containing element X are placed in a ball mill under an inert atmosphere and dry-milled to obtain dry ball-milled powder;

[0010] After the dry grinding is completed, a wet grinding eluent is added to the ball mill under an inert atmosphere to perform wet grinding to obtain wet ball milled powder, which is then dried and sintered to obtain a non-layered low thermal conductivity indium selenide-based material.

[0011] In one embodiment, the In solid powder is: indium powder with a purity of 99.99wt% to 99.999wt%, the Se solid powder is: selenium powder with a purity of 99.9wt% to 99.999wt%, and the solid powder containing the X element is: any one of indium iodide powder with a purity of 99wt% to 99.999wt%, tellurium powder with a purity of 99wt% to 99.99wt%, and lanthanum powder with a purity of 99wt% to 99.99wt%.

[0012] In one embodiment, the inert atmosphere is argon or nitrogen.

[0013] In one embodiment, the rotation speed of the dry ball milling is 300-500 rpm, the ball-to-material ratio of the dry ball milling is (15-30):1, and the dry ball milling time is 8-15 hours; the rotation speed of the wet ball milling is 250 rpm, and the wet ball milling time is 2-5 hours.

[0014] In one embodiment, the drying time is 12 hours, and the drying temperature is 60-90 degrees Celsius.

[0015] In one embodiment, the sintering temperature is 200-400 degrees Celsius, the sintering pressure is 30-70 MPa, and the sintering time is 5-20 minutes.

[0016] In one embodiment, the sintering method is spark plasma sintering or hot pressing sintering.

[0017] The third aspect of the present invention provides the use of the above-mentioned non-layered low thermal conductivity indium selenide-based material in thermal insulation materials, heat insulating materials and thermoelectric energy conversion materials.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The preparation method of the non-layered low thermal conductivity indium selenide-based material provided by the present invention has abundant raw material sources, low cost, simple production process and production equipment, and good controllability and repeatability. The initial raw materials are sequentially dry-milled and wet-milled to obtain powder, and then dried and sintered to directly obtain the non-layered low thermal conductivity indium selenide-based material without the need for steps such as melting, thereby streamlining and optimizing the preparation steps and process and saving costs.

[0020] The non-layered low thermal conductivity indium selenide-based material provided by the present invention has a special monoclinic crystal structure and low thermal conductivity. The room temperature thermal conductivity is 0.6 W / mK and the maximum thermal conductivity is 0.82 W / mK (99K), which is lower than the existing binary selenide thermoelectric materials.

[0021] The non-layered low thermal conductivity indium selenide-based material provided by the present invention can reduce the thermal conductivity of the material by doping with iodine, tellurium, and lanthanum elements, thereby further improving the thermoelectric performance of the corresponding material. The non-layered low thermal conductivity indium selenide-based material provided by the present invention has uniform element distribution and stable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0023] Figure 1 This is a schematic flow chart of a method for preparing a non-layered low thermal conductivity indium selenide-based material according to the present invention;

[0024] Figure 2 The dry powder (InSe), bulk material (InSe) obtained in Comparative Example 1 and the non-layered low thermal conductivity indium selenide-based material (InSe) obtained in Examples 1-3 are 0.99 I 0.01 ,InSe 0.9 Te 0.1 ,In 0.99 SeLa 0.01 )’s XRD spectrum;

[0025] Figure 3 The non-layered low thermal conductivity indium selenide-based material (InSe 0.99 I 0.01 ,InSe 0.9 Te 0.1 ,In 0.99 SeLa 0.01 ) and the element distribution energy spectrum of the bulk material (InSe) obtained in Comparative Example 1;

[0026] Figure 4 is the thermal conductivity of the bulk material (InSe) obtained in Comparative Example 1 and other binary selenide thermoelectric materials;

[0027] Figure 5 The non-layered low thermal conductivity indium selenide-based material (InSe 0.99 I 0.01 ,InSe 0.9 Te 0.1 ,In 0.99 SeLa 0.01 ) and the thermal conductivity of the bulk material (InSe) obtained in Comparative Example 1. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0029] The present invention provides a non-layered low thermal conductivity indium selenide-based material and its preparation method and application. The chemical formula of the material is In x Se y X z , where X is any element among I, Te, and La, x = 1 or x = 1-z, y = 1 or y = 1-z, and z = 0.01-0.1. Non-layered specifically refers to InSe-based materials with a monoclinic crystal structure. This InSe-based material has low thermal conductivity and has broad application prospects in thermoelectric materials and thermal insulation.

[0030] Next, the preparation method of the above-mentioned indium selenide-based material is described:

[0031] like Figure 1 As shown, the preparation method of the non-layered low thermal conductivity indium selenide-based material provided by the present invention is: according to the chemical formula In x Se y X z In solid powder, Se solid powder, and solid powder containing element X are weighed in a stoichiometric ratio, wherein X is any one of I, Te, and La; the weighed In solid powder, Se solid powder, and solid powder containing element X are placed in a ball mill under an inert atmosphere and dry-milled to obtain dry ball-milled powder; after the dry milling is completed, a wet milling eluent is added to the ball mill under an inert atmosphere and wet-milled to obtain a wet ball-milled powder, which is then dried and sintered to obtain a non-layered low thermal conductivity indium selenide-based material.

[0032] In some embodiments, the In solid powder is: indium powder with a purity of 99.99wt% to 99.999wt%, the Se solid powder is: selenium powder with a purity of 99.9wt% to 99.999wt%, and the solid powder containing the X element is: any one of indium iodide powder with a purity of 99wt% to 99.999wt%, tellurium powder with a purity of 99wt% to 99.99wt%, and lanthanum powder with a purity of 99wt% to 99.99wt%.

[0033] In some embodiments, the inert atmosphere is argon, nitrogen, or a binary mixed gas of argon or nitrogen containing a small amount of hydrogen.

[0034] In some embodiments, the rotation speed of dry ball milling is 300-500 rpm, the ball-to-material ratio of dry ball milling is (15-30):1, and the dry ball milling time is 8-15 hours; the rotation speed of wet ball milling is 250 rpm, and the wet ball milling time is 2-5 hours.

[0035] In some embodiments, the eluent selected in the preparation method is intended to remove the powder after dry ball milling. Therefore, the eluent must not react chemically with the indium selenide-based material. Ethanol is an option. Furthermore, the amount of eluent used is sufficient to remove the powder after dry ball milling, typically ranging from 30 to 60 ml.

[0036] In some embodiments, the drying time is 12 hours and the drying temperature is 60-90 degrees Celsius.

[0037] In some embodiments, the sintering method is spark plasma sintering or hot pressing sintering, the sintering temperature is 200-400 degrees Celsius, the sintering pressure is 30-70 MPa, and the sintering time is 5-20 minutes.

[0038] The present invention will be further explained in detail below in conjunction with the embodiments:

[0039] Example 1

[0040] This embodiment provides a non-layered low thermal conductivity indium selenide-based material with a chemical formula of InSe 0.99 I 0.01 .

[0041] The chemical formula in this embodiment is InSe 0.99 I 0.01 The preparation method of the non-layered low thermal conductivity indium selenide-based material is as follows:

[0042] Indium powder with a purity of 99.99-99.999wt%, selenium powder with a purity of 99.9-99.999wt%, and indium iodide (InI3) powder with a molar ratio of 2.99:2.97:0.01 were weighed. The powders and stainless steel balls were then placed in a stainless steel ball mill in a nitrogen-filled glove box, achieving a ball-to-material ratio of 15:1. Dry milling was then performed at 450 rpm for 10 hours. Under a protective atmosphere, 30 ml of ethanol was added to the mill, and wet milling was continued at 250 rpm for 2 hours. The resulting suspension was transferred to a glass Petri dish using a pipette and dried in an oven for at least 12 hours to obtain a dry powder.

[0043] The obtained dry powder was subjected to spark plasma sintering at a sintering temperature of 400 degrees Celsius, a pressure of 50 MPa, and a sintering time of 5 minutes, and finally a dense bulk material (non-layered low thermal conductivity indium selenide-based material) was obtained.

[0044] The XRD spectrum of the bulk material (non-layered low thermal conductivity indium selenide-based material) obtained in this embodiment is as follows: Figure 2 shown.

[0045] Example 2

[0046] This embodiment provides a non-layered low thermal conductivity indium selenide-based material with a chemical formula of InSe 0.9 T e0.1 .

[0047] The chemical formula in this embodiment is InSe 0.9 T e0.1 The preparation method of the non-layered low thermal conductivity indium selenide-based material is as follows:

[0048] Indium powder with a purity of 99.99-99.999wt%, selenium powder with a purity of 99.9-99.999wt%, and tellurium powder with a molar ratio of 1:0.9:0.1 were weighed. The powders and stainless steel balls were then placed in a stainless steel ball mill in a nitrogen-filled glove box, with a ball-to-material ratio of 20:1. Dry milling was then performed at 450 rpm for 15 hours. Under a protective atmosphere, 60 ml of ethanol was added to the mill, and wet milling was continued at 250 rpm for 5 hours. The resulting suspension was transferred to a glass Petri dish using a pipette and dried in an oven for at least 12 hours to obtain a dry powder.

[0049] The obtained dry powder was subjected to spark plasma sintering at a sintering temperature of 300 degrees Celsius, a pressure of 50 MPa, and a sintering time of 5 minutes, and finally a dense bulk material (non-layered low thermal conductivity indium selenide-based material) was obtained.

[0050] The XRD spectrum of the non-layered low thermal conductivity indium selenide-based material obtained in this embodiment is as follows Figure 2 shown.

[0051] Example 3

[0052] This embodiment provides a non-layered low thermal conductivity indium selenide-based material, the chemical formula of which is In 0.99 SeLa 0.01 .

[0053] In this embodiment, the chemical formula is In 0.99 SeLa 0.01 The preparation method of the non-layered low thermal conductivity indium selenide-based material is as follows:

[0054] Indium powder with a purity of 99.99wt% to 99.999wt%, selenium powder with a purity of 99.9wt% to 99.999wt%, and lanthanum powder with a molar ratio of 0.99:1:0.01 were weighed. The powders and stainless steel balls were then placed in a stainless steel ball mill in a nitrogen-filled glove box, with a ball-to-material ratio of 30:1. Dry milling was then performed at 450 rpm for 10 hours. Under a protective gas atmosphere, 50 ml of ethanol was added to the mill, and wet milling was continued at 250 rpm for 3 hours. The resulting suspension was transferred to a glass Petri dish using a dropper and dried in an oven for at least 12 hours to obtain a dry powder.

[0055] The obtained dry powder was subjected to spark plasma sintering at a sintering temperature of 300 degrees Celsius, a pressure of 50 MPa, and a sintering time of 5 minutes, and finally a dense bulk material (non-layered low thermal conductivity indium selenide-based material) was obtained.

[0056] The XRD spectrum of the non-layered low thermal conductivity indium selenide-based material obtained in this embodiment is as follows Figure 2 shown.

[0057] Comparative Example 1

[0058] This comparative example provides a material with a chemical formula of InSe. The preparation method of the material with a chemical formula of InSe in this comparative example is as follows:

[0059] Indium powder with a purity of 99.99% to 99.999% by weight and selenium powder with a purity of 99.9% to 99.999% by weight were weighed in a 1:1 molar ratio. The powders and stainless steel balls were then placed in a stainless steel ball mill in a nitrogen-filled glove box, with a ball-to-material ratio of 20:1. Dry milling was then performed at 450 rpm for 12 hours. Under a protective atmosphere, 50 ml of ethanol was added to the mill, and wet milling was continued at 250 rpm for 3 hours. The resulting suspension was transferred to a glass Petri dish using a dropper and dried in an oven for at least 12 hours to obtain a dry powder.

[0060] The obtained dry powder was subjected to spark plasma sintering at a sintering temperature of 320 degrees Celsius, a pressure of 70 MPa, and a sintering time of 10 minutes to finally obtain a dense block material.

[0061] The XRD spectrum of the bulk material (InSe) obtained in this comparative example is as follows Figure 2 shown.

[0062] The XRD spectrum of the dry powder (InSe) obtained in this comparative example is as follows Figure 2 shown.

[0063] Experimental Example 1

[0064] An Oxford-EDS spectrometer was used to analyze the elemental ratios of Examples 1-3 and Comparative Example 1. During the test, an incident electron beam raster-scanned the sample surface. The spectrometer fixedly received characteristic X-ray information of certain elements. Each time a characteristic X-ray photon was collected, a bright spot was generated at the corresponding position on the screen, thereby obtaining a surface distribution map of different elements.

[0065] Figure 3 Examples 1-3 (InSe 0.99 I 0.01 ,InSe 0.9 Te 0.1 ,In 0.99 SeLa 0.01 ) and comparative example 1 (InSe) non-layered low thermal conductivity indium selenide-based materials, wherein there is no element agglomeration or enrichment, indicating that the elements of the prepared non-layered low thermal conductivity indium selenide-based materials are evenly distributed and the block quality is good.

[0066] Experimental Example 2

[0067] The thermal conductivity of a material is given by the formula It can be calculated that, where Cp is the specific heat capacity, estimated by the Dulong-Petit law; d is the material density, measured by the Archimedean principle; λ is the thermal diffusivity, measured by a laser thermal conductivity meter (LFA-457). Before measurement, the sample is polished into a thin sheet with a specification of about 6mm×6mm×1mm, sprayed with a uniform and thin layer of carbon powder on both sides, and then placed in a lithium tantalate mold. Liquid nitrogen is added and the circulating water is turned on to prevent damage to the instrument due to heat. Protective gas is continuously introduced during the test. After heating the sample to the set temperature, the system generates a laser and hits the sample. The sample gradually heats up under the action of the laser, and the temperature signal on the back is received by the temperature detector. The thickness of the sample is measured before the experiment, and combined with the detection signal recorded by the instrument, the formula is used. Calculate the thermal diffusivity.

[0068] Reference Figure 4 As shown, the thermal conductivity of the InSe bulk sample of Comparative Example 1 is the lowest compared to other binary selenides, indicating that non-layered indium selenide-based materials, i.e., monoclinic indium selenide-based materials, perform better than other binary selenides. The thermal conductivity data of other binary selenides are from the following literature: hex-InSe, Shi H, et al. Aggregate 2021; In2Se3, Cui J, et al. J Mater Chem C 2015; In4Se3, Luu SDN, et al. ACS Appl Energy Mater 2020; SnSe, Wei TR, et al. Phys Chem Chem Phys 2015; Cu2Se, Jin Z, et al. Mater Today Phys 2021; PbSe, Zhou NN, et al. ACS ApplEnerg Mater 2021.

[0069] Reference Figure 5 As shown, the non-layered low thermal conductivity indium selenide-based materials of Examples 1, 2 and 3 synthesized by doping any one of iodine, tellurium and lanthanum can significantly reduce the value of the thermal conductivity of the material and improve the performance of the material.

[0070] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A non-layered low thermal conductivity indium selenide-based material, characterized in that: The chemical formula of the non-layered low thermal conductivity indium selenide-based material is In x Se y X z , where X is any element among I, Te, and La, x=1 or x=1-z, y=1 or y=1-z, and z=0.01~0.1; The non-layered low thermal conductivity indium selenide-based material has a monoclinic crystal structure; The method for preparing the non-layered low thermal conductivity indium selenide-based material comprises the following steps: According to the chemical formula of non-layered low thermal conductivity indium selenide x Se y X z Weigh In solid powder, Se solid powder, and solid powder containing element X in a stoichiometric ratio, wherein X is any one of I, Te, and La; The weighed In solid powder, Se solid powder, and solid powder containing element X are placed in a ball mill under an inert atmosphere and dry-milled to obtain dry ball-milled powder; After the dry grinding is completed, a wet grinding eluent is added to the ball mill under an inert atmosphere to perform wet grinding to obtain wet ball milled powder, which is then dried and sintered to obtain a non-layered low thermal conductivity indium selenide-based material.

2. The non-layered low thermal conductivity indium selenide-based material according to claim 1, characterized in that: The In solid powder is: indium powder with a purity of 99.99wt% to 99.999wt%, the Se solid powder is: selenium powder with a purity of 99.9wt% to 99.999wt%, and the solid powder containing the X element is: any one of indium iodide powder with a purity of 99wt% to 99.999wt%, tellurium powder with a purity of 99wt% to 99.99wt%, and lanthanum powder with a purity of 99wt% to 99.99wt%.

3. The non-layered low thermal conductivity indium selenide-based material according to claim 1, characterized in that: The inert atmosphere is argon or nitrogen.

4. The non-layered low thermal conductivity indium selenide-based material according to claim 1, characterized in that: The rotation speed of the dry ball mill is 300-500 rpm, the ball-to-material ratio of the dry ball mill is (15-30):1, and the dry ball milling time is 8-15 hours; the rotation speed of the wet ball mill is 250 rpm, and the wet ball milling time is 2-5 hours.

5. The non-layered low thermal conductivity indium selenide-based material according to claim 1, characterized in that: The drying time is 12 hours, and the drying temperature is 60-90 degrees Celsius.

6. The non-layered low thermal conductivity indium selenide-based material according to claim 3, characterized in that: The sintering temperature is 200-400 degrees Celsius, the sintering pressure is 30-70 MPa, and the sintering time is 5-20 minutes.

7. The non-layered low thermal conductivity indium selenide-based material according to claim 1, characterized in that: The sintering method is spark plasma sintering or hot pressing sintering.

8. Use of the non-layered low thermal conductivity indium selenide-based material according to claim 1 in thermal insulation materials, heat insulating materials and thermoelectric energy conversion materials.

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