Tungsten-doped ZrNiSn thermoelectric composite material, preparation method and application thereof
By introducing tungsten nanoparticles into the ZrNiSn matrix, band alignment and energy filtering barriers are formed, and high-performance, low-cost tungsten-doped ZrNiSn thermoelectric composite materials are prepared. This solves the problems of high thermal conductivity and high cost of ZrNiSn thermoelectric materials and achieves a high-efficiency improvement in thermoelectric performance.
Patent Information
- Application Number
- CN202511586627.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-02
- Publication Date
- 2026-03-13
AI Technical Summary
Existing ZrNiSn thermoelectric materials suffer from performance degradation due to high thermal conductivity and narrow bandgap, and the high cost of Hf limits its large-scale application.
Tungsten nanoparticles were introduced into the ZrNiSn matrix to form band alignment through the energy filtering effect, which promoted carrier injection and established an energy filtering barrier. Tungsten-doped ZrNiSn thermoelectric composite materials were prepared by combining the discharge plasma sintering technology.
It significantly improves the power factor and dimensionless figure of merit of thermoelectric materials, reduces raw material costs, and provides an economically feasible solution for large-scale applications.
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Figure CN121665895A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of thermoelectric materials technology, and in particular to a tungsten-doped ZrNiSn thermoelectric composite material, its preparation method, and its application. Background Technology
[0002] Thermoelectric (TE) devices, as an all-solid-state energy conversion solution, have significant application value in waste heat recovery and precision thermal management, covering fields such as consumer electronics, communications, biomedicine, and automotive technology. The performance of thermoelectric materials is typically characterized by the dimensionless figure of merit zT;
[0003]
[0004] Where T is the absolute temperature, S is the Seebeck coefficient, σ is the electrical conductivity, and κ is the total thermal conductivity. The total thermal conductivity (κ) is derived from the electronic thermal conductivity (κ). e ) and lattice thermal conductivity (κ) L Thermoelectric materials consist of two parts. There are two main methods to optimize their performance: reducing lattice thermal conductivity (κ). L Both increasing the thermoelectric power factor (PF=S²σ) and improving the thermoelectric power factor (PF=S²σ) are important, but these two factors often have a mutually restrictive relationship. Semi-Hessler compounds, due to their excellent mechanical strength and oxidation resistance, have become the preferred system for medium- and high-temperature thermoelectric materials. Among them, n-type ZrNiSn (space group F...) 3m) has significant potential, but its simple cubic lattice leads to high thermal conductivity ( The narrow bandgap (0.4~0.5 eV) induces high-temperature bipolar conduction, which in turn degrades the Seebeck coefficient (S).
[0005] Currently, the most effective strategy is to introduce Hf at the Zr site for isoelectronic substitution. The significant mass and size mismatch between Zr and Hf can simultaneously induce mass fluctuations and strain field scattering, resulting in a substantial reduction in thermal conductivity (κ). However, Hf is expensive, costing as much as $4220 / kg, accounting for a significant portion of the price of typical formulations (Hf...). 0.75 Zr 0.25 NiSn 0.99 Sb 0.01 The cost of raw materials accounts for 99% of the cost, which severely restricts large-scale application. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the present invention aims to provide a tungsten-doped ZrNiSn thermoelectric composite material, its preparation method, and its application. By combining tungsten modulation doping with the energy filtering effect, the bottleneck of PF-zT coupling optimization in semi-Hessler materials is overcome, significantly improving the PF and zT values of the thermoelectric material while reducing raw material costs, thus providing a solution for the large-scale application of thermoelectric materials.
[0007] This invention provides a tungsten-doped ZrNiSn thermoelectric composite material, which uses ZrNiSn as the matrix, mixes ZrNiSn powder with W nanoparticles uniformly, and then rapidly densifies to obtain the ZrNiSn-W thermoelectric composite material.
[0008] In the preferred embodiment, the doping amount of W nanoparticles is 1~5wt%.
[0009] This invention also provides a method for preparing a tungsten-doped ZrNiSn thermoelectric composite material, comprising the following steps:
[0010] S1. Zr ingots, Ni ingots, and Sn wires are induction melted under argon protection according to the stoichiometric ratio to obtain ingots;
[0011] S2. The obtained ingot is crushed and mechanically ground under argon protection to mechanically alloy it, thus obtaining ZrNiSn powder.
[0012] S3. The obtained ZrNiSn powder is mixed evenly with W nanoparticles, and the mixed powder is sintered by spark plasma to obtain a completely dense bulk, namely the tungsten-doped ZrNiSn thermoelectric composite material.
[0013] In step S1, the melting time is 2~30 minutes.
[0014] In step S1, the ingot is rotated and remelted 2 to 4 times to ensure uniformity.
[0015] In step S2, a SPEX ball mill is used for high-energy ball milling for 2 to 6 hours, and the grinding media is stainless steel grinding balls.
[0016] In step S3, the particle size of W nanoparticles is 40~100 nm.
[0017] In step S3, ZrNiSn powder and W nanoparticles are mixed evenly using a SPEX ball mill.
[0018] In step S3, spark plasma sintering (SPS) is performed, specifically by applying a pressure of 60-100 MPa at 800-1000°C for 1-10 minutes.
[0019] The present invention also provides a single-coupled device, wherein the N-type leg of the device is made of the aforementioned ZrNiSn-W thermoelectric composite material, and the P-type leg is made of... Material.
[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:
[0021] This invention introduces a tungsten nanoprecipitate phase into a ZrNiSn matrix for the first time, which can form band alignment at the W / ZrNiSn hetero interface, promote carrier injection, and establish an energy filtering barrier to preferentially transport high-energy electrons. This strategy enables the peak power factor (PF) of the tungsten-doped ZrNiSn thermoelectric composite material to reach [value missing]. (910 K), zT value reaches 0.76.
[0022] The present invention chooses tungsten doping because of its extremely high melting point (3422°C), which can suppress grain coarsening of the ZrNiSn matrix during SPS sintering at 900°C, thereby retaining stable nanoscale inclusions.
[0023] This invention eliminates the hafnium element, providing a scalable and low-cost solution for the large-scale application of semi-Hessler thermoelectric materials, reducing raw material costs by more than 95%, and providing an economical solution for the large-scale deployment of thermoelectric materials.
[0024] Based on this N-type material and P-type The constructed single-coupled device achieved a conversion efficiency (η) of 5.2% and [missing value] at a temperature difference of 307 K. Power density. Attached Figure Description
[0025] Figure 1 The XRD patterns of the synthesized ZrNiSn-W thermoelectric composite materials (doped at 0, 1wt%, 3wt%, and 5wt%) are shown.
[0026] Figure 2 The HAADF-STEM spectrum of ZrNiSn-3%W prepared in Example 1.
[0027] Figure 3 for Figure 2 The corresponding Fast Fourier Transform and EDS mapping spectrum.
[0028] Figure 4 The conductivity (σ) spectrum of the synthesized ZrNiSn-W sample is shown.
[0029] Figure 5 The Seebeck coefficient (S) of the synthesized ZrNiSn-W sample varies with temperature.
[0030] Figure 6 The thermoelectric properties of the synthesized ZrNiSn-W sample: power factor (PF).
[0031] Figure 7 The thermoelectric properties of the synthesized ZrNiSn-W sample: lattice thermal conductivity (κ) L ).
[0032] Figure 8 The thermoelectric properties of the synthesized ZrNiSn-W sample: dimensionless figure of merit zT.
[0033] Figure 9 The graphs show the conversion efficiency and power density of the single-couple device constructed in Example 4 at different temperatures. Detailed Implementation
[0034] The specific embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The raw materials used in the implementation of the present invention are as follows:
[0035] Zirconium ingots (99.9% purity, Alfa Aesar, USA); Nickel ingots (99.995% purity, Alfa Aesar, USA); Tin wire (99.95% purity, Alfa Aesar, USA); Tungsten nanoparticles (99.7% purity, Sky Spring Nanomaterials, USA).
[0036] The present invention will be further described below with reference to specific embodiments and accompanying drawings:
[0037] Comparative Example 1
[0038] S1. According to the stoichiometric ratio, Zr ingot, Ni ingot and Sn wire are induction melted for 5 minutes under argon protection to obtain an ingot. The ingot is flipped and remelted three times to ensure the uniformity of composition.
[0039] S2. After crushing the obtained ingot, transfer it to a stainless steel ball mill jar (model 8000D, SPEX SamplePrep, Metuchen, NJ) and mechanically grind it for 4 hours under argon protection to mechanically alloy it and obtain ZrNiSn powder.
[0040] S3. The obtained ZrNiSn powder was sintered by spark plasma sintering (SPS, model Dr. Sinter-625V, Fuji, Japan) at 900°C and 80 MPa for 5 min to obtain ZrNiSn thermoelectric material.
[0041] Example 1
[0042] A method for preparing a tungsten-doped ZrNiSn thermoelectric composite material includes the following steps:
[0043] S1. According to the stoichiometric ratio, Zr ingot, Ni ingot and Sn wire are induction melted for 5 minutes under argon protection to obtain an ingot. The ingot is flipped and remelted three times to ensure the uniformity of composition.
[0044] S2. After crushing the obtained ingot, transfer it to a stainless steel ball mill jar (model 8000D, SPEX SamplePrep, Metuchen, NJ) and mechanically grind it for 4 hours under argon protection to mechanically alloy it and obtain ZrNiSn powder.
[0045] S3. The obtained ZrNiSn powder is mixed evenly with W nanoparticles. The doping amount of W nanoparticles is 3wt%, and the particle size of W nanoparticles is 40~100 nm. The mixed powder is sintered by spark plasma sintering (SPS, model Dr. Sinter-625V, Fuji, Japan) at 900°C and 80 MPa pressure for 5 min to obtain a completely dense bulk, namely the tungsten-doped ZrNiSn thermoelectric composite material.
[0046] Example 2
[0047] By changing the doping amount of W nanoparticles to 1 wt%, and keeping the remaining preparation steps the same as in Example 1, a tungsten-doped ZrNiSn thermoelectric composite material was obtained.
[0048] Example 3
[0049] By changing the doping amount of W nanoparticles to 5wt%, and keeping the remaining preparation steps the same as in Example 1, a tungsten-doped ZrNiSn thermoelectric composite material was obtained.
[0050] Example 4
[0051] In this embodiment, the single-coupled device is fabricated based on existing technology: the N-type leg of the device uses the tungsten-doped ZrNiSn thermoelectric composite material (ZrNiSn-3%W) prepared in Example 1, and the P-type leg uses... Material.
[0052] The thermoelectric device was fabricated based on the technique reported in our previous work [W. Li, B. Poudel, A. Nozariasbmarz, R. Sriramdas, H. Zhu, HB Kang, S. Priya, Adv. Energy Mater. 2020, 10, 2001924]. First, the synthesized ZrNiSn-3%W bulk sintered body was thoroughly polished and cleaned by ultrasonic stirring to remove surface contaminants. Subsequently, a uniform nickel layer was deposited on the surface of the sintered body as a barrier layer by electroless nickel plating. Next, the coated sintered body was precisely cut into thermoelectric arms with dimensions of 1.5 mm (length) × 1.5 mm (width) × 2.3 mm (height).
[0053] The P-arm adopts the design reported by Zhang et al. The material [W. Li, J. Wang, Y. Xie, JL Gray, JJ Heremans, HB Kang, B. Poudel, ST Huxtable, S. Priya, Chem. Mater. 2019, 31, 862-872] has dimensions of 1.5 mm × 2 mm × 2.3 mm. An N-type ZrNiSn-3% W thermoelectric arm with a pre-prepared nickel barrier layer and a P-type... The thermoelectric arms are soldered to a copper substrate using tin / lead solder to assemble a single-arm / single-couple thermoelectric module.
[0054] Figure 1 The X-ray diffraction pattern of the synthesized ZrNiSn-W thermoelectric composite material confirms that the ZrNiSn-W thermoelectric composite material is a cubic half-Hessler phase (space group F). (3m, JCPDS No. 01-072-2587) After W doping, the main diffraction peak positions of ZrNiSn did not shift, indicating that the lattice parameters of the matrix remained unchanged, confirming that W did not chemically react with the ZrNiSn matrix. Simultaneously, a secondary W phase (JCPDS No. 00-004-0806) was confirmed in the diffraction pattern, and the intensity of the W peak increased with increasing W nanoparticle concentration.
[0055] Figures 2-3 The HAADF-STEM image of ZrNiSn-3%W prepared for Example 1, along with the corresponding Fast Fourier Transform and EDS mapping spectra, confirm the cubic semi-Hessler structure (space group F). The presence of 3m was consistent with the XRD results, and it was found that tungsten nanoparticles preferentially precipitated at grain boundaries; high-resolution EDS mapping further verified the uniform distribution of nano-inclusions in the matrix. Figure 3 Meanwhile, smaller tungsten nanoparticles can be observed randomly distributed within the grains. These tungsten nanoparticles are visible in the HAADF image ( Figure 2 In tungsten EDS mapping, the region with higher brightness appears as a brighter area. Figure 3 It is also clearly visible in the text.
[0056] Figure 4 The conductivity spectra of the synthesized ZrNiSn-W nanocomposites show the temperature dependence of electronic transport properties. The conductivity (σ) of each sample increases with increasing temperature, confirming its intrinsic semiconductor properties. At 300 K, the conductivity of pure ZrNiSn is 3.0 × 10⁻⁶. 4 The electrical conductivity of the 3 wt.% W composite material increased to 3.6 × 10⁻⁶. 4 The improvement was 20%, which was attributed to the introduction of additional charge carriers by the W nanoparticles.
[0057] Figure 5 The graph shows the Seebeck coefficient (S) of the synthesized ZrNiSn-W samples as a function of temperature. The Seebeck coefficient (S) of all samples is negative, which confirms their n-type conductivity. It is worth noting that at 300 K, the Seebeck coefficient (S) increases slightly with the increase of tungsten (W) content (1~5 wt.%).
[0058] Figure 6 The synergistic improvement of power factor (PF) and conductivity (σ) while maintaining a high Seebeck coefficient (S) in the synthesized ZrNiSn-W sample resulted in a significant enhancement of the power factor (PF) across the entire temperature range; the ZrNiSn-3%W composition reached 44 at 910 K. The high peak power factor highlights the potential of the ZrNiSn-W nanocomposite strategy in high power density, high-efficiency thermoelectric generator (TEG) applications.
[0059] Figure 7 The lattice thermal conductivity of the synthesized ZrNiSn-W sample is ( As can be seen from the figure, the lattice thermal conductivity of ZrNiSn-3%W is ( )lowest.
[0060] Figure 8 The dimensionless figure of merit (zT) of the synthesized ZrNiSn-W samples was obtained. All W-doped samples retained the same bipolar thermal conductivity recovery trend as the original ZrNiSn, confirming that the W particles did not chemically react with the matrix or change the electronic band structure of the host material. Finally, the introduction of 3 wt.% W nanoparticles into ZrNiSn increased the carrier concentration (nH) through charge carrier injection, and the small energy barrier formed at the same time filtered low-energy electrons, thereby simultaneously improving the conductivity (σ) and Seebeck coefficient, achieving a peak dimensionless figure of merit (zT) of 0.76 at 910 K.
[0061] like Figure 9 As shown, tests have shown that the N-type material (ZrNiSn-3%W) and the P-type material... The constructed single-coupled device achieved a conversion efficiency (η) of 5.2% and [missing value] at a temperature difference of 307 K. Power density provides a scalable and low-cost solution for the large-scale application of thermoelectric materials.
[0062] The tungsten (W)-based nanocomposite strategy can significantly reduce material costs, with a cost reduction of more than 95% compared to traditional hafnium (Hf)-containing systems, while maintaining competitive ZT values and device-level performance (see table below).
[0063]
[0064]
[0065] The above are merely preferred embodiments of the present invention, and only describe the implementation of the present invention. They are not intended to limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.
Claims
1. A tungsten-doped ZrNiSn thermoelectric composite material, characterized in that, Using ZrNiSn as the matrix, ZrNiSn powder and W nanoparticles were mixed uniformly and rapidly densified to obtain ZrNiSn-W thermoelectric composite material.
2. The tungsten-doped ZrNiSn thermoelectric composite material according to claim 1, characterized in that, The doping amount of W nanoparticles is 1~5wt%.
3. A method for preparing a tungsten-doped ZrNiSn thermoelectric composite material, characterized in that, Includes the following steps: S1. Zr ingots, Ni ingots, and Sn wires are induction melted under argon protection according to the stoichiometric ratio to obtain ingots; S2. The obtained ingot is crushed and mechanically ground under argon protection to mechanically alloy it, thus obtaining ZrNiSn powder. S3. The obtained ZrNiSn powder is mixed evenly with W nanoparticles, and the mixed powder is sintered by spark plasma to obtain a completely dense bulk, namely the tungsten-doped ZrNiSn thermoelectric composite material.
4. The method for preparing a tungsten-doped ZrNiSn thermoelectric composite material according to claim 3, characterized in that, In step S1, the melting time is 2~30 minutes.
5. The method for preparing a tungsten-doped ZrNiSn thermoelectric composite material according to claim 3, characterized in that, In step S1, the ingot is rotated and remelted 2 to 4 times to ensure uniformity.
6. The method for preparing a tungsten-doped ZrNiSn thermoelectric composite material according to claim 3, characterized in that, In step S2, a SPEX ball mill is used for high-energy ball milling for 2 to 6 hours, and the grinding media is stainless steel grinding balls.
7. The method for preparing a tungsten-doped ZrNiSn thermoelectric composite material according to claim 3, characterized in that, In step S3, the particle size of W nanoparticles is 40~100 nm.
8. The method for preparing a tungsten-doped ZrNiSn thermoelectric composite material according to claim 3, characterized in that, In step S3, ZrNiSn powder and W nanoparticles are mixed evenly using a SPEX ball mill.
9. The method for preparing a tungsten-doped ZrNiSn thermoelectric composite material according to claim 3, characterized in that, In step S3, spark plasma sintering (SPS) is performed, specifically by applying a pressure of 60-100 MPa at 800-1000°C for 1-10 minutes.
10. A single-pair device, characterized in that, The N-type leg of the device uses the ZrNiSn-W thermoelectric composite material as described in claim 1 or 2, and the P-type leg uses... Material.