Graphdiyne-doped BiSbTe-based thermoelectric material and preparation method and application thereof

Abstract

The invention relates to the technical field of thermoelectric materials, and discloses a graphdiyne-doped BiSbTe-based thermoelectric material and a preparation method and application thereof.The preparation method comprises the steps that (Bi, Sb) 2Te3 powder and graphdiyne powder are mixed and sintered, and the graphdiyne-doped BiSbTe-based thermoelectric material is obtained. Benefited from collaborative optimization of electroacoustic transport, the graphdiyne-doped BiSbTe-based thermoelectric material provided by the invention shows thermoelectric performance far superior to that of a contrast sample (an undoped material) in a wide temperature range of 300K to 500K. The thermoelectric figure of merit (ZT value) is obviously improved, the highest ZT value can reach 1.1 or above, and the excellent room-temperature and near-room-temperature thermoelectric conversion efficiency is shown.

Description

Technical Field

[0001] This invention relates to the field of thermoelectric materials technology, and in particular to a graphdiyne-doped BiSbTe-based thermoelectric material, its preparation method, and its application. Background Technology

[0002] Thermoelectric materials are functional materials capable of converting heat energy into electrical energy and vice versa, with broad application prospects in fields such as solid-state refrigeration, waste heat power generation, and precise temperature control. Their performance is determined by the dimensionless thermoelectric figure of merit ZT: ZT = S 2 σT / (κ L +κe), where S is the Seebeck coefficient, σ is the conductivity, T is the absolute temperature, and κe is the electrical conductivity. L Phokon thermal conductivity is the lattice (phonon) thermal conductivity, while κe is the carrier thermal conductivity (proportional to electrical conductivity). Therefore, ideal high-performance thermoelectric materials need to simultaneously possess high electrical conductivity (low resistance), high Seebeck coefficient (large thermoelectric potential), and low thermal conductivity (good thermal insulation performance). How to synergistically regulate the thermal and electrical transport properties to improve the thermoelectric figure of merit is a key issue that materials researchers cannot avoid.

[0003] Bi₂Te₃-based materials are the best-performing thermoelectric materials near room temperature to date. Among them, the p-type (Bi,Sb)₂Te₃ solid solution formed by adjusting the Bi and Sb ratio (i.e., BiSbTe-based thermoelectric materials, such as Bi…) 0.4 Sb 1.6 Te3 is the core of research and application. However, the ZT value of traditional (Bi,Sb)2Te3 materials (BST) remains limited, mainly due to the strong coupling relationship between electrical and thermal properties: reducing the lattice thermal conductivity (κ) through nanostructuring, introducing defects, etc. L At the same time, it often severely scatters charge carriers, leading to a significant decrease in conductivity (σ), thus failing to effectively improve the overall ZT value.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a graphdiyne-doped BiSbTe-based thermoelectric material, its preparation method and application, aiming to solve the problem of reduced carrier mobility caused by strong electroacoustic transport coupling in BiSbTe-based thermoelectric materials.

[0006] In a first aspect, the present invention provides a method for preparing a graphdiyne-doped BiSbTe-based thermoelectric material, the method comprising the following steps: (Bi,Sb)2Te3 powder was mixed with graphyne powder and sintered to obtain the graphyne-doped BiSbTe-based thermoelectric material.

[0007] Preferably, the mass ratio of (Bi,Sb)2Te3 powder to graphyne powder is 100:(0.1-1).

[0008] Preferably, the particle size of the (Bi,Sb)2Te3 powder is 0.1-10 micrometers, and the particle size of the graphyne powder is 0.1-10 micrometers.

[0009] Preferably, the preparation of the (Bi,Sb)₂Te₃ powder includes the following steps: Bi powder, Sb powder and Te powder are placed in a ball mill and a process control agent is added for ball milling to obtain the (Bi,Sb)2Te3 powder. Alternatively, Bi powder, Sb powder, and Te powder can be used as raw materials to prepare (Bi,Sb)2Te3 polycrystalline bulk material using a melt-quenching method. The (Bi,Sb)2Te3 polycrystalline bulk material can then be placed in a ball mill with a process control agent added for ball milling to obtain the (Bi,Sb)2Te3 powder.

[0010] Preferably, the ball milling parameters are: ball-to-material ratio of (10-30):1, rotation speed of 300-500 rpm, and ball milling time of 2-10 hours.

[0011] Preferably, the process control agent includes one or more of stearic acid, anhydrous ethanol, and isopropanol.

[0012] Preferably, the step of mixing (Bi,Sb)₂Te₃ powder with graphyne powder specifically includes: Graphdiyne powder was dissolved in an organic solvent and subjected to a first ultrasonic treatment to obtain a graphdiyne suspension. The (Bi,Sb)2Te3 powder was mixed evenly with the graphdiyne suspension and subjected to a second ultrasonic treatment to obtain a mixed solution. The mixed solution is subjected to supercritical CO2 drying or heating treatment to obtain composite powder, thus completing the step of mixing (Bi,Sb)2Te3 powder with graphyne powder. Alternatively, (Bi,Sb)₂Te₃ powder and graphyne powder can be placed in a mixer and dry-mixed using a ball mill or V-type mixer to complete the mixing of (Bi,Sb)₂Te₃ powder and graphyne powder.

[0013] Preferably, the process parameters for the first ultrasonic treatment are: ultrasonic frequency greater than or equal to 40 kHz, ultrasonic treatment for 30-60 minutes in an ice bath environment and at full power. The process parameters for the second ultrasonic treatment are: magnetic stirring for more than 8 hours, ultrasonic frequency greater than or equal to 40 kHz, and ultrasonic treatment for 10-20 minutes under full power conditions.

[0014] Preferably, the sintering process includes one of spark plasma sintering, flash sintering, Joule heating, and hot pressing sintering.

[0015] Preferably, the sintering process is spark plasma sintering.

[0016] Preferably, the parameters for the spark plasma sintering are: sintering at 380℃-450℃ for 3-10 minutes under a pressure of 40-80 MPa.

[0017] In a second aspect, the present invention provides a graphdiyne-doped BiSbTe-based thermoelectric material prepared by the above-described preparation method.

[0018] A third aspect of the present invention provides the application of the above-described graphyne-doped BiSbTe-based thermoelectric material in solid-state refrigeration, waste heat power generation, and precise temperature control.

[0019] The present invention has the following beneficial effects: This invention proposes a graphdiyne-doped BiSbTe-based thermoelectric material, its preparation method, and its applications. The preparation method includes the following steps: mixing (Bi,Sb)₂Te₃ powder with graphdiyne powder and sintering to obtain the graphdiyne-doped BiSbTe-based thermoelectric material. The beneficial effects of this preparation method include at least the following aspects: 1. Achieving synergistic regulation of electro-acoustic transport: By introducing a unique additive (graphdiyne powder), this invention successfully achieves synergistic optimization and effective decoupling of electron and phonon transport in BiSbTe-based thermoelectric materials, overcoming the problem of mutual constraints between electrical and thermal properties in traditional thermoelectric materials. 2. High thermoelectric performance and low thermal conductivity: Based on the above synergistic regulation, this invention can significantly enhance phonon scattering and substantially reduce lattice thermal conductivity while maintaining the excellent electrical properties of BiSbTe-based thermoelectric materials, such as high carrier mobility and high conductivity, thereby fundamentally optimizing the thermoelectric quality factor of BiSbTe-based thermoelectric materials. 3. Achieving a Breakthrough ZT Value: Thanks to the synergistic optimization of electroacoustic transport, the graphdiyne-doped BiSbTe-based thermoelectric material provided by this invention exhibits thermoelectric performance far exceeding that of the comparative sample (undoped material) over a wide temperature range of 300K to 500K. Its thermoelectric figure of merit (ZT value) is significantly improved, with the highest ZT value reaching over 1.1, demonstrating excellent room temperature and near-room temperature thermoelectric conversion efficiency. Attached Figure Description

[0020] Figure 1 SEM morphology images: (left) Undoped BST (Bi0.4 Sb 1.6 Te3); (middle) Graphdiyne-doped BST (GDY@Bi 0.4 Sb 1.6 Te3); (right) XRD pattern; Figure 2 The results of thermoelectric performance tests are shown in the graphs: (a) electrical conductivity, (b) lattice thermal conductivity, (c) Seebeck coefficient S and (d) ZT as a function of temperature. Detailed Implementation

[0021] This invention provides a graphdiyne-doped BiSbTe-based thermoelectric material, its preparation method, and its applications. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] The ZT value of traditional (Bi,Sb)₂Te₃ materials remains limited, primarily due to the strong coupling between electrical and thermal properties. To overcome this bottleneck, existing technologies mainly focus on optimizing (Bi,Sb)₂Te₃ materials in the following aspects: Microstructure control: Nanoscale (Bi,Sb)₂Te₃ powders are prepared using methods such as ball milling and hydrothermal methods, followed by rapid densification using techniques such as spark plasma sintering (SPS) to retain the nanostructure in the bulk material. These nanograin boundaries can effectively scatter mid- and long-wavelength phonons, reducing the lattice thermal conductivity κ. L Band engineering: By introducing specific doping elements (such as Cu, Ag, I, Se, etc.), the carrier concentration and band structure are adjusted to improve the power factor (PF = S²σ). Composite low-dimensional carbon materials: In recent years, research has attempted to composite carbon nanotubes (CNTs) or graphene with a (Bi,Sb)₂Te₃ matrix. These carbon materials can theoretically form conductive networks and act as additional phonon scattering centers.

[0024] Despite some progress in existing technologies, significant shortcomings remain: 1. Limited and unsynergistic performance improvements: Simple microstructural manipulation, while reducing thermal conductivity, often compromises electrical performance. Furthermore, band engineering has a saturation limit for improving the power factor. 2. Interface problems in carbon material composites: Traditional carbon nanotubes or graphene exhibit poor interfacial bonding with the (Bi,Sb)₂Te₃ matrix, easily introducing high-energy barriers and leading to a significant decrease in carrier mobility. Moreover, the inert surfaces of these carbon materials struggle to achieve effective chemical interactions with the (Bi,Sb)₂Te₃ matrix, failing to maximize their phonon scattering capability. 3. Difficulty in achieving synergistic decoupling of "electron transport-phonon transport": Existing methods struggle to find an additive that can selectively and strongly scatter phonons (reducing κ) L Furthermore, it is harmless or even beneficial to carrier transport (maintaining or increasing σ). This is precisely the key scientific issue limiting further breakthroughs in the ZT value of (Bi,Sb)₂Te₃ materials.

[0025] Therefore, there is still a need in the field for a new material design and preparation method that can effectively decouple electroacoustic transmission and synergistically optimize electrical and thermal properties, thereby significantly improving the thermoelectric figure of merit of BiSbTe-based thermoelectric materials.

[0026] Based on this, embodiments of the present invention provide a method for preparing a graphdiyne-doped BiSbTe-based thermoelectric material, the preparation method comprising the following steps: (Bi,Sb)2Te3 powder was mixed with graphyne powder and sintered to obtain the graphyne-doped BiSbTe-based thermoelectric material.

[0027] The core of the technical solution described above in this invention lies in the innovative introduction of graphodyne with a unique two-dimensional structure as an additive. Utilizing its multifaceted intrinsic properties, synergistic optimization and decoupled control are achieved from both electrical and thermal transport dimensions. The specific working principle is explained as follows: 1. Electrical Transport Optimization Principle: Electrically, the unique two-dimensional in-plane sp and sp² hybridization of graphodyne forms a highly conjugated system capable of forming extensive and close interfacial contact with the (Bi,Sb)₂Te₃ matrix material. This interface not only provides good physical contact, but more importantly, the Fermi level of graphodyne has a suitable energy level matching relationship with the valence band top of the (Bi,Sb)₂Te₃ matrix. This energy level matching effectively reduces the potential barrier for carrier (hole) transport at the interface, providing an efficient channel for holes to cross between the two phases. Therefore, in the graphyne-doped BiSbTe-based thermoelectric material of this invention, the introduction of graphyne not only does not significantly negatively impact conductivity due to the introduction of the second phase, but may even maintain or slightly improve the conductivity of the (Bi,Sb)₂Te₃ matrix material by optimizing interfacial transport characteristics, thus preserving excellent fundamental electrical properties. 2. Thermal transport suppression (reduction of lattice thermal conductivity) principle: In terms of thermal properties, this invention utilizes the multi-scale structural characteristics of graphyne to construct an efficient phonon scattering network, specifically reducing the lattice thermal conductivity of the material. ① Two-dimensional planar scattering: The two-dimensional sheets of graphyne dispersed in the (Bi,Sb)₂Te₃ matrix constitute nanoscale barriers to phonon propagation paths, effectively scattering medium and long-wavelength phonons. ② Pore and interface scattering: The inherently porous structure uniformly distributed on the graphyne plane, and the numerous heterogeneous interfaces between graphyne and the (Bi,Sb)₂Te₃ matrix, can scatter higher-frequency phonons with shorter wavelengths. ③ Weak bonding enhances scattering: Crucially, the weak bonding that may form at the interface significantly reduces the group velocity of phonons and induces strong anharmonic scattering. This is essential for scattering low-frequency phonons with extremely long mean free paths, which are difficult to effectively interact with by traditional nanoscale second phases. Through the combined effects of the two-dimensional sheets, porous structure, heterojunction, and weak bonding, this embodiment of the invention achieves multi-level, efficient scattering of phonons across the entire wavelength range (especially low-frequency phonons), thereby significantly reducing the lattice thermal conductivity of the composite material.

[0028] In summary, the introduction of graphdiene optimizes carrier transport and preserves electrical conductivity through its energy level structure and conjugation properties. Furthermore, its multi-scale geometry and interfacial characteristics significantly enhance phonon scattering and reduce thermal conductivity. These two aspects work together to successfully achieve decoupled control of the three key parameters—Seebeck coefficient, electrical conductivity, and thermal conductivity—ultimately resulting in a synergistic and substantial improvement in the thermoelectric figure of merit (ZT value) of the material in the 300–500 K temperature range.

[0029] In some embodiments, the graphyne powder is nitrogen-doped graphyne powder.

[0030] The technical principle of doping graphyne with nitrogen atoms is as follows: 1. Electronic structure regulation: The introduction of nitrogen atoms can form effective n-type doping on the carbon framework of graphyne, increasing the carrier concentration of the material by providing additional valence electrons, thereby helping to improve the electrical conductivity of the composite material. Simultaneously, the incorporation of nitrogen atoms can regulate and potentially reduce the band gap of intrinsic graphyne, optimizing its Seebeck coefficient, which is beneficial for obtaining a higher power factor. 2. Phonon transport suppression: The difference in mass and bond strength between nitrogen atoms and carbon atoms introduces point defects and lattice distortion in the graphyne lattice. Furthermore, nitrogen doping sites may form weak bonds with metal atoms (such as Bi and Sb) in the BiSbTe matrix. These factors can effectively scatter mid- and high-frequency phonons, significantly enhancing the interfacial phonon scattering effect, thereby helping to reduce the overall lattice thermal conductivity of the composite material.

[0031] In summary, the synergistic effect of nitrogen doping aims to simultaneously optimize electron transport performance and suppress phonon transport, ultimately achieving a synergistic improvement in the thermoelectric figure of merit of composite materials.

[0032] In some embodiments, copper and / or manganese dioxide are added to the mixed powder obtained by mixing (Bi,Sb)₂Te₃ powder and graphyne powder. By doping with metals or metal oxides, the carrier concentration, band structure, phonon scattering centers, etc. of the matrix are adjusted, thereby optimizing its electrical and thermal properties.

[0033] In some embodiments, the mass ratio of (Bi,Sb)₂Te₃ powder to graphyne powder is 100:(0.1-1). The mass ratio of (Bi,Sb)₂Te₃ powder to graphyne powder can be 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, or 100:1.

[0034] If too little graphite diyne powder is added, it is impossible to adjust and optimize the electrical and thermal properties; if too much graphite diyne powder is added, excessive impurities and defects will be introduced, which will reduce the mechanical properties and thermal stability of the sintered bulk.

[0035] In some preferred embodiments, the mass ratio of the (Bi,Sb)2Te3 powder to the graphylene powder is 100:(0.3-0.6).

[0036] In some embodiments, the particle size of the (Bi,Sb)₂Te₃ powder is 0.1-10 micrometers, and the particle size of the graphyne powder is 0.1-10 micrometers.

[0037] If the grain size of (Bi,Sb)₂Te₃ powder is too small, although it greatly reduces thermal conductivity, it will severely impair electrical conductivity; if the grain size is too large, it can maintain high electrical conductivity, but cannot effectively reduce thermal conductivity, thus limiting the improvement of ZT value. Graphdiyne powder and BST powder have similar particle sizes, which facilitates their uniform mixing.

[0038] In some preferred embodiments, the particle size of the (Bi,Sb)₂Te₃ powder is 0.5-5 micrometers, and the particle size of the graphyne powder is 0.5-5 micrometers.

[0039] In some embodiments, the preparation of the (Bi,Sb)₂Te₃ powder includes the following steps: Bi powder, Sb powder and Te powder are placed in a ball mill and a process control agent is added for ball milling to obtain the (Bi,Sb)2Te3 powder. Alternatively, Bi powder, Sb powder, and Te powder can be used as raw materials to prepare (Bi,Sb)2Te3 polycrystalline bulk material using a melt-quenching method. The (Bi,Sb)2Te3 polycrystalline bulk material can then be placed in a ball mill with a process control agent added for ball milling to obtain the (Bi,Sb)2Te3 powder.

[0040] In some embodiments, the ball milling parameters are: a ball-to-material ratio of (10-30):1, a rotation speed of 300-500 rpm, and a milling time of 2-10 hours. In other embodiments, the ball milling parameters are: a ball-to-material ratio of 10:1, 15:1, 20:1, 25:1, or 30:1; a rotation speed of 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm; and a milling time of 2 hours, 3 hours, 4 hours, 5 hours, 7 hours, or 10 hours.

[0041] In some preferred embodiments, the ball milling parameters are: a ball-to-material ratio of 20:1, a rotation speed of 400 rpm, and a ball milling time of 5 hours.

[0042] In some embodiments, the process control agent includes one or more of stearic acid, anhydrous ethanol, and isopropanol.

[0043] In some embodiments, the step of mixing (Bi,Sb)₂Te₃ powder with graphyne powder specifically includes: Graphdiyne powder was dissolved in an organic solvent and subjected to a first ultrasonic treatment to obtain a graphdiyne suspension. The (Bi,Sb)2Te3 powder was mixed evenly with the graphdiyne suspension and subjected to a second ultrasonic treatment to obtain a mixed solution. The mixed solution is subjected to supercritical CO2 drying or heating treatment to obtain composite powder, thus completing the step of mixing (Bi,Sb)2Te3 powder with graphyne powder. Alternatively, (Bi,Sb)₂Te₃ powder and graphyne powder can be placed in a mixer and dry-mixed using a ball mill or V-type mixer to complete the mixing of (Bi,Sb)₂Te₃ powder and graphyne powder.

[0044] In some embodiments, the process parameters of the first ultrasonic treatment are: ultrasonic frequency greater than or equal to 40 kHz, ultrasonic treatment for 30-60 minutes in an ice bath environment and at full power to ensure that the graphite diyne sheets are fully peeled off and dispersed. The process parameters for the second ultrasonic treatment are: magnetic stirring for more than 8 hours, ultrasonic frequency greater than or equal to 40 kHz, and ultrasonic treatment for 10-20 minutes under full power conditions to ensure uniform mixing of graphdiene and BST powder.

[0045] In some preferred embodiments, the process parameters of the first ultrasonic treatment are: ultrasonic frequency of 40 kHz, ultrasonic treatment for 60 minutes in an ice bath environment and at full power to ensure that the graphite diyne sheets are fully peeled and dispersed. The process parameters for the second ultrasonic treatment are: magnetic stirring for 12 hours, ultrasonic power of 40 kHz, and ultrasonic treatment for 15 minutes under full power conditions to ensure uniform mixing of graphdiene and BST powder.

[0046] In some embodiments, the sintering process is selected from one of spark plasma sintering, flash sintering, Joule heating, and hot pressing sintering.

[0047] In some embodiments, the sintering process is spark plasma sintering.

[0048] Spark plasma sintering (SPS technology) generates plasma between powder particles using pulsed high current, achieving purification and activation of the particle surface. It can densify the graphyne-doped BiSbTe-based thermoelectric material powder at a low temperature and in a very short time (minutes), inhibiting excessive grain growth and protecting the graphyne (GDY) nanostructure and GDY / BST interface.

[0049] In some embodiments, the parameters for the spark plasma sintering are: sintering at 380°C-450°C for 3-10 minutes under a pressure of 40-80 MPa.

[0050] In some preferred embodiments, the parameters for the spark plasma sintering treatment are: sintering at 400°C for 5 minutes under a pressure of 50 MPa.

[0051] This invention provides a graphdiyne-doped BiSbTe-based thermoelectric material prepared by the above-described preparation method.

[0052] The embodiments of the present invention provide the application of the above-mentioned graphdiyne-doped BiSbTe-based thermoelectric material in solid-state refrigeration, waste heat power generation, and precise temperature control.

[0053] The following detailed description uses specific examples.

[0054] Example The preparation of graphdiyne-doped BiSbTe-based thermoelectric materials includes the following steps: Step 1: Bi 2-x Sb x Preparation of Te3 (x=0-2) nano- and micro-powders Bi 0.4 Sb 1.6 Taking Te3 as an example, high-purity elemental Bi powder, Sb powder, and Te powder were weighed according to stoichiometric ratio. An appropriate amount of these raw materials was placed in a ball mill jar, and 5% stearic acid was added as a process control agent. Zirconia balls with diameters of 5 mm and 10 mm were then added. Under argon protection, ball milling was performed at a ball-to-material ratio of 20:1 and a speed of 400 rpm for 5 hours. After ball milling, Bi particles with uniform particle size distribution and a size between 0.1 and 10 micrometers were obtained. 0.4 Sb 1.6 Te3 nanoparticles.

[0055] Step 2: Uniform compounding with graphdiene First, graphite yttrium powder (measured in Bi) 0.4 Sb 1.6 0.3 wt.% of Te3 nanoparticle powder was dispersed in anhydrous ethanol and subjected to ultrasonic treatment (ultrasonic bath for more than 60 minutes) to prepare a graphdiyne suspension. The Bi obtained in step one was then... 0.4 Sb 1.6 Te3 nanoparticle powder is mixed with graphylene suspension, sonicated for more than 10 minutes, and magnetically stirred for more than 5 hours. After the two are uniformly mixed, composite powder is obtained by supercritical CO2 drying system or heat treatment (less than 60°C).

[0056] Step 3: Spark Plasma Sintering (SPS) The uniformly mixed composite powder was loaded into a graphite mold and placed in an SPS sintering furnace. Under vacuum (<10 Pa) conditions, an axial pressure of 50 MPa was applied, and then the temperature was increased to 400°C at a heating rate of 100°C / min and held at that temperature and pressure for 5 minutes. The material was then cooled with the furnace to obtain the graphdiyne-doped BiSbTe-based thermoelectric material.

[0057] Performance characterization and testing The BiSbTe-based thermoelectric materials obtained in the examples were characterized as follows to verify their excellent performance: Structural characterization: X-ray diffraction was used to analyze the phases, and scanning electron microscopy / transmission electron microscopy was used to observe the microstructure, grain size, and distribution of graphyne (C).

[0058] Thermoelectric performance testing: Electrical conductivity and Seebeck coefficient: measured using a thermoelectric material performance testing system (ZEM).

[0059] Lattice thermal conductivity: κ = λρCp, where λ is the thermal diffusivity (measured by laser scintillation), ρ is the material density (Archimedes method), and Cp is the specific heat capacity (measured by DSC or theoretical value).

[0060] Calculate the ZT value: Based on the above data, calculate ZT = (S²σT) / κ.

[0061] Experimental results: Undoped pure Bi 0.4 Sb 1.6 Bi doped with Te3 and 0.3 wt.% GDY 0.4 Sb 1.6 Te3 (GDY@Bi) 0.4 Sb 1.6 The density of Te3, measured by the Archimedes method, was 6.605 g / cm³. 3 and 6.256 g / cm 3 Since the doping concentration is very low, the effect of doping on the specific heat capacity is ignored, and the specific heat capacity Cp is adopted as the literature value of 0.19 J·g. -1 ·K -1 The relevant structural and performance characterization results are attached. Figure 1 and 2 SEM results showed that the graphyne-doped BiSbTe-based thermoelectric material had a more uniform grain size. Compared to undoped pure BiSbTe, the graphyne-doped BiSbTe-based thermoelectric material prepared in this embodiment of the invention... 0.4 Sb 1.6 Te3 material exhibits a relatively constant electrical conductivity (σ) or a slight increase near room temperature, a significant increase in Seebeck coefficient (S) and a significant decrease in lattice thermal conductivity κL, ultimately resulting in a substantial increase in ZT value throughout the entire test temperature range, with a peak ZT value greater than 1.1.

[0062] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a graphdiyne-doped BiSbTe-based thermoelectric material, characterized in that, The preparation method includes the following steps: (Bi,Sb)2Te3 powder was mixed with graphyne powder and sintered to obtain the graphyne-doped BiSbTe-based thermoelectric material.

2. The method for preparing the graphdiyne-doped BiSbTe-based thermoelectric material according to claim 1, characterized in that, The mass ratio of (Bi,Sb)2Te3 powder to graphyne powder is 100:(0.1–1).

3. The method for preparing the graphdiyne-doped BiSbTe-based thermoelectric material according to claim 2, characterized in that, The mass ratio of (Bi,Sb)2Te3 powder to graphyne powder is 100: (0.3–0.5).

4. The method for preparing the graphdiyne-doped BiSbTe-based thermoelectric material according to claim 1, characterized in that, The particle size of the (Bi,Sb)2Te3 powder is 0.1-10 micrometers, and the particle size of the graphyne powder is 0.1-10 micrometers.

5. The method for preparing the graphdiyne-doped BiSbTe-based thermoelectric material according to claim 1, characterized in that, The specific steps for mixing (Bi,Sb)₂Te₃ powder with graphyne powder are as follows: Graphdiyne powder was dissolved in an organic solvent and subjected to a first ultrasonic treatment to obtain a graphdiyne suspension. The (Bi,Sb)2Te3 powder was mixed evenly with the graphdiyne suspension and subjected to a second ultrasonic treatment to obtain a mixed solution. The mixed solution is subjected to supercritical CO2 drying or heating treatment to obtain composite powder, thus completing the step of mixing (Bi,Sb)2Te3 powder with graphyne powder. Alternatively, (Bi,Sb)₂Te₃ powder and graphyne powder can be placed in a mixer and dry-mixed using a ball mill or V-type mixer to complete the mixing of (Bi,Sb)₂Te₃ powder and graphyne powder.

6. The method for preparing the graphdiyne-doped BiSbTe-based thermoelectric material according to claim 5, characterized in that, The process parameters for the first ultrasonic treatment are: ultrasonic frequency greater than or equal to 40 kHz, ultrasonic treatment for 30-60 minutes in an ice bath environment and at full power. The process parameters for the second ultrasonic treatment are: magnetic stirring for more than 8 hours, ultrasonic frequency greater than or equal to 40 kHz, and ultrasonication for 10-20 minutes under full power conditions.

7. The method for preparing the graphdiyne-doped BiSbTe-based thermoelectric material according to claim 1, characterized in that, The sintering process includes one of the following: spark plasma sintering, flash sintering, Joule heating, and hot pressing sintering.

8. The method for preparing the graphdiyne-doped BiSbTe-based thermoelectric material according to claim 7, characterized in that, The sintering process is spark plasma sintering. The parameters for the discharge plasma sintering are: sintering at 380℃-450℃ for 3-10 minutes under a pressure of 40-80 MPa.

9. A graphdiyne-doped BiSbTe-based thermoelectric material prepared by the preparation method according to any one of claims 1-8.

10. The application of the graphdiyne-doped BiSbTe-based thermoelectric material as described in claim 9 in solid-state refrigeration, waste heat power generation, and precise temperature control.

Images