A flexible, lightweight thermoelectric material resistant to strong ultraviolet radiation at ultra-low temperatures and its preparation method

Abstract

This invention discloses a flexible, lightweight thermoelectric material resistant to strong ultraviolet radiation at ultra-low temperatures and its preparation method. Macroscopic carbon nanotube films are synthesized using a floating catalyst chemical vapor deposition method. The macroscopic carbon nanotube films are then subjected to heat treatment, hydrochloric acid treatment, and chlorosulfonic acid treatment to obtain the flexible, lightweight thermoelectric material resistant to strong ultraviolet radiation at ultra-low temperatures. The carbon nanotube films prepared by this invention, after treatment with hydrochloric acid and chlorosulfonic acid, maintain a thermoelectric power factor of 7.3 mW / m² at 100 K. ‑1 K ‑2 The treated carbon nanotube film maintained high stability for over 108 hours under ultraviolet radiation at 254 / 365 nm. Assembling the treated carbon nanotube film into a single-legged thermoelectric generator demonstrated its thermoelectric conversion capability at ultra-low temperatures, achieving a weight-to-weight power density of 5730 μW / g. ‑1 .

Description

Technical Field

[0001] This invention belongs to the field of thermoelectric energy conversion technology, and relates to a flexible and lightweight thermoelectric material with ultra-low temperature resistance to strong ultraviolet radiation and its preparation method. Background Technology

[0002] Developing new renewable energy sources and improving energy efficiency have become important directions for technological development today. In extreme environments and special applications, such as Arctic / Antarctic expeditions or deep space exploration under conditions of ultra-low temperature and strong ultraviolet radiation, reliable power sources are in high demand [Nat. Mater. 17, 846-850 (2018); Adv. Mater. 36, 2400020 (2024)]. High-performance thermoelectric power generation devices can achieve direct energy conversion between thermal and electrical energy through an all-solid-state structure. The power generation device has a simple structure, does not require liquid flow or moving parts, is noiseless, can work for a long time, and has no emissions or pollution, making it highly reliable in these applications [Adv. Energy Mater. 11, 2100920 (2021); Nat. Mater. 21, 503-513 (2022)]. In addition, unlike photovoltaic devices [Nat. Nanotechnol. 9, 126-130 (2014); Adv. Mater. 30, 1707-271 (2018); Science 360, 904-907 (2018)], thermoelectric power generation can operate in the absence of light, thus expanding its application in dark environments such as the Arctic / Antarctic polar night and deep space conditions.

[0003] Traditional thermoelectric devices are mostly made of inorganic materials. Although these materials have high thermoelectric performance, they usually suffer from problems such as high cost, weight, material toxicity, and poor environmental stability [Nano Energy 121,109213(2024); Joule 3,53-80(2019)], such as tellurium and bismuth [Nat. Commun. 14,4932(2023); J. Mater. Chem. C 11,4056-4069(2023); Nano Energy 126,109651(2024)]. Organic thermoelectric materials are flexible and lightweight, but their performance is not as good as that of inorganic materials, and their operating temperature is usually limited to around 300K or slightly higher [Nat. Commun. 9,3817(2018); Nano Energy 80,105488(2021)]. Therefore, exploring flexible, lightweight, and high-power-factor thermoelectric materials has become a research hotspot in the field of thermoelectrics [Science 377, 854-858 (2022); Adv. Mater. 31, 1807916 (2019); Adv. Energy Mater. 10, 1902842 (2020)], and the preparation of materials that can be used in extreme environments such as low temperature and ultraviolet radiation remains challenging [Adv. Funct. Mater. 31, 2104071 (2021)].

[0004] With the development of nanotechnology, low-dimensional nanostructured materials such as carbon nanotubes (CNTs) can simultaneously achieve high power factors, lightweight, and flexibility [Adv. Funct. Mater. 32, 2203080 (2022); Nat. Commun. 12, 4931 (2021); Nat. Commun. 14, 380 (2023)]. Due to the narrow carrier distribution caused by quantum confinement, significant progress has been made in improving the thermoelectric power factor of one-dimensional / two-dimensional nanomaterials. Large power factors have been achieved in some studies; for example, the power factor of monolayer graphene is 36.6 mW / m². -1 K -2 [P.Natl.Acad.Sci.113,14272-14276(2016)], the power factor of a single CNT is 100mW / m. -1 K -2 [Jpn.J.Appl.Phys.58,075003(2019)]. However, these high power factors remain difficult to achieve in macroscopic materials, with only a few research groups successfully realizing macroscopic CNT thin films at 1 mW / m². -1 K -2 -9.3mW m -1 K -2High power factor within the range [Adv. Funct. Mater. 32, 2203080 (2022); Small 19, 2304266 (2023); Nat. Commun. 14, 380 (2023); Nat. Commun. 15, 5617 (2024)]. Furthermore, research on materials resistant to low temperatures and strong ultraviolet radiation remains lacking [Adv. Funct. Mater. 32, 2203080 (2022); Small 19, 2304266 (2023); Nat. Commun. 14, 380 (2023); Nat. Commun. 15, 5617 (2024)]. When the temperature drops to 175 K, flexible and lightweight (density ≤ 2.50 g cm⁻¹) -3 The power factor of thermoelectric materials is less than 90 μW / m. -1 K -2 [Adv.Funct.Mater.32,2111435(2022)]. Therefore, it is crucial to develop flexible, lightweight, and high-power-factor thermoelectric materials, and thermoelectric power generation devices that can be used in extreme environments such as low temperatures. Summary of the Invention

[0005] To overcome the problem of low power factor in existing thermoelectric materials, the present invention aims to provide a flexible and lightweight thermoelectric material with resistance to strong ultraviolet radiation at ultra-low temperatures and a preparation method thereof.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a flexible, lightweight thermoelectric material resistant to ultra-low temperature and strong ultraviolet radiation includes the following steps:

[0008] Macroscopic carbon nanotube films were synthesized by floating catalyst chemical vapor deposition.

[0009] By heat treatment, hydrochloric acid and chlorosulfonic acid treatment of macroscopic carbon nanotube films, a flexible and lightweight thermoelectric material with ultra-low temperature resistance to strong ultraviolet radiation was obtained.

[0010] Furthermore, macroscopic carbon nanotube films are prepared through the following process:

[0011] Ferrocene and thiophene were dissolved in n-hexane and methanol to obtain a precursor solution;

[0012] The precursor solution was injected into a reactor at 1573–1773 K, and then nitrogen gas was used to send the precursor solution into the high-temperature zone of a horizontal furnace to obtain carbon nanotube aerogel.

[0013] By pressurizing carbon nanotube aerogel, macroscopic carbon nanotube films are obtained.

[0014] Furthermore, the molar ratio of ferrocene to thiophene is 5.72:1, the volume ratio of n-hexane to methanol is 1:4, and the molar ratio of ferrocene to n-hexane is 14.3 mmol:14 mL.

[0015] Furthermore, the temperature in the high-temperature zone is 1573–1773 K.

[0016] Furthermore, the pressurization pressure is 4-5 tons, and the time is 5-10 minutes.

[0017] Furthermore, the macroscopic carbon nanotube film is subjected to heat treatment, hydrochloric acid, and chlorosulfonic acid to obtain a flexible and lightweight thermoelectric material that is resistant to strong ultraviolet radiation at ultra-low temperatures, including the following steps:

[0018] Macroscopic carbon nanotube films were heated at 1173–1373 K in an inert atmosphere for 16–18 h, then soaked in hydrochloric acid and dried, followed by densification treatment with chlorosulfonic acid at 323–523 K to form CNTs. treated film;

[0019] CNT treated The thin film was dedoped under nitrogen protection to obtain a flexible and lightweight thermoelectric material that is resistant to strong ultraviolet radiation at ultra-low temperatures.

[0020] Furthermore, the hydrochloric acid concentration was 36-38%, and the soaking time was 1-4 hours.

[0021] Furthermore, the dedoping treatment is carried out at a temperature of 373K-1273K for a time of 15min-120min.

[0022] A flexible, lightweight thermoelectric material that is resistant to strong ultraviolet radiation at ultra-low temperatures.

[0023] Furthermore, in a single-leg device with a heat sink temperature of 93K and a heat source of 303K, the weight output power density of the ultra-low temperature resistant, strong ultraviolet radiation-resistant flexible, lightweight thermoelectric material reaches as high as 5730 μW g. -1 .

[0024] Compared with the prior art, the present invention has significant beneficial effects:

[0025] In this invention, a flexible, lightweight thermoelectric material with ultra-low temperature resistance to strong ultraviolet radiation is obtained by heat treatment, hydrochloric acid, and chlorosulfonic acid on a macroscopic carbon nanotube film. The material exhibits 7.3 mW / m² at 100 K. -1 K -2 The high thermoelectric power factor is among the highest of the most advanced p-type flexible thermoelectric materials at ultra-low temperatures. The ZT value of this invention after acid treatment is almost independent of temperature, approaching the ZT values ​​of some inorganic materials at ultra-low temperatures, such as CePd. 2.95(at 150K ~0.17) and Ce(Ni) 0.8 Cu 0.2 Al3 (0.04 at 150 K). The flexible and lightweight thermoelectric material exhibits excellent flexibility at ultra-low temperatures; the film can still fluctuate in liquid nitrogen when tweezers are swung. The conductivity and Seebeck coefficient can be recovered after rapid heating in the range of 77–300 K. After 108 h of irradiation with 254 / 365 nm UV light, the conductivity and Seebeck coefficient of the carbon nanotube film remain unchanged. In a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the carbon nanotube film reaches as high as 5730 μW g. -1 It exhibits excellent thermoelectric conversion capabilities. The results show that carbon nanotube films have potential applications under ultra-low temperature and strong ultraviolet radiation conditions, such as Arctic / Antarctic exploration or deep space exploration. Attached Figure Description

[0026] Figure 1 A schematic diagram illustrating the mechanism for preparing carbon nanotube films with resistance to strong ultraviolet radiation at ultra-low temperatures.

[0027] Figure 2 A schematic diagram illustrating the synthesis of carbon nanotube thin films.

[0028] Figure 3 CNTs prepared in Example 1 as-syn SEM images of the thin film, where (a) is the morphology at low magnification, (b) is the morphology at high magnification, (c) is the cross-section at low magnification, and (d) is the cross-section at high magnification.

[0029] Figure 4 CNTs prepared in Example 1 treated SEM images of the thin film, where (a) is the morphology at low magnification, (b) is the morphology at high magnification, (c) is the cross-section at low magnification, and (d) is the cross-section at high magnification.

[0030] Figure 5 CNTs prepared in Example 1 treated-H / 30 SEM images of the thin film, where (a) is the morphology at low magnification, (b) is the morphology at high magnification, (c) is the cross-section at low magnification, and (d) is the cross-section at high magnification.

[0031] Figure 6 CNTs prepared in Example 1 treated-H / 30 Curves showing the changes in thin film conductivity and Seebeck coefficient with temperature.

[0032] Figure 7 CNTs prepared in Example 1 treated-H / 30 The changes in thin-film resistance and Seebeck coefficient with liquid nitrogen immersion time.

[0033] Figure 8 CNTs prepared in Example 1 treated-H / 30 A schematic diagram of the thin film bending experiment in liquid nitrogen and a graph showing the changes in resistance and Seebeck coefficient with the number of bending cycles. In the graph, (a) is the bending experiment diagram and (b) is the change curve.

[0034] Figure 9 CNTs prepared in Example 1 treated-H / 30 The experimental diagram of the thin film under ultraviolet light irradiation and the curves showing the changes in resistance and Seebeck coefficient with ultraviolet light irradiation are shown. In the figure, (a) is the experimental diagram of ultraviolet light irradiation and (b) is the curve.

[0035] Figure 10 CNTs prepared in Example 1 treated-H / 30 A schematic diagram of thin film output performance test and a comparison diagram of the surface output power density and weight output power density of the thermoelectric device under different temperature differences with the macroscopic flexible thermoelectric device in the literature. Among them, (a) is the output performance test diagram and (b) is the comparison diagram of the surface output power density and weight output power density of the thermoelectric device.

[0036] Figure 11 CNTs prepared in Example 1 treated-H / 30 A comparison of the overall performance of the thin film and the p-type thermoelectric film reported in the literature. Detailed Implementation

[0037] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0038] See Figure 1 and Figure 2 This invention discloses a method for preparing a flexible, lightweight thermoelectric material resistant to strong ultraviolet radiation at ultra-low temperatures. The method involves synthesizing a highly conductive macroscopic carbon nanotube film using floating catalyst chemical vapor deposition (FCCVD), followed by high-temperature treatment with hydrochloric acid and chlorosulfonic acid (CSA). The specific steps include:

[0039] (1) Carbon nanotube aerogels were synthesized in a horizontal furnace using nitrogen as the carrier gas at a flow rate of 0.5 L / min to 1 L / min. Ferrocene and thiophene were dissolved in n-hexane and methanol and treated with ultrasound for 30 min to prepare a precursor solution. The precursor solution was injected into a reactor (a horizontal furnace at 1573–1773 K) at a rate of 0.5–3 mL / min. Then, nitrogen gas at a flow rate of 0.5–15 L / min carried the precursor solution into the high-temperature zone of the horizontal furnace at a temperature of 1573–1773 K to obtain carbon nanotube aerogels. Finally, the carbon nanotube aerogels were discharged from the reactor into the air by nitrogen gas and collected by a drum. The molar ratio of ferrocene to thiophene was 5.72:1, the volume ratio of n-hexane to methanol was 1:4, and the molar ratio of ferrocene to n-hexane was 14.3 mmol:14 mL.

[0040] (2) The carbon nanotube aerogel prepared in step (1) was collected using a 10cm diameter winding cylinder, which was wrapped with sulfate paper. During the preparation process, the winding speed was adjusted to 1–5 mm / s. A certain amount of methanol was sprayed during collection. After 30 minutes of collection, the film was peeled off the cylinder. Then, it was compressed for 5–10 minutes using a tablet press (MSK-2150, China) with a force of 4–5 tons to make the film surface smooth and dense, thus preparing CNTs. as-syn membrane;

[0041] (3) Remove the CNT from step (2) as-syn The thin film was placed in a tube furnace and heated at 1173–1373 K in an inert atmosphere for 16–18 h, followed by immersion in concentrated hydrochloric acid for 1–4 h. The film treated with concentrated hydrochloric acid (36–38% by mass) for 1–4 h was then immersed three times in deionized water and dried in air at room temperature. After drying, the film was immersed in CSA at 323–523 K to densify it, forming CNTs. treated film;

[0042] (4) Remove the CNT from step (3) treated The thin film is heated under nitrogen protection at a nitrogen flow rate of 0.01 L / min to optimize the acid doping level under different operating conditions. Specifically, doping is performed at different temperatures of 373 K-1273 K for 15 min-120 min. Preferably, acid doping is performed at (373 K, 573 K, 773 K, 973 K and 1273 K, with a dedoping time of 30 min) and (dedoping temperature of 773 K, with dedoping times of 15 min, 30 min, 60 min and 120 min) to obtain the optimized CNT thin film, which is the flexible lightweight thermoelectric material, and forms a single-leg thermoelectric power generation device.

[0043] During the testing of the thermoelectric power generation device, the cold junction temperature was adjusted by liquid nitrogen, and the hot junction temperature was controlled at around 303K by a heating element. The output voltage was obtained using a Keithley 2400 multimeter.

[0044] (5) Performance Testing: Seebeck coefficient and conductivity were measured using commercial equipment (NETZSCH SBA-458, Germany). Conductivity was determined using the four-probe method. Seebeck coefficient and conductivity were obtained simultaneously using a bidirectional heating test method. Thermal conductivity was measured using a commercial instrument (VTET-01). Three or more samples were tested for each data point. Two different types of ultraviolet light with wavelengths of 254 nm and 365 nm were used to simulate ultraviolet light irradiation in outer space or at high altitudes.

[0045] Scanning electron microscope (SEM) images were obtained using a FEIQUANTA 250FEG from the USA.

[0046] Transmission electron microscopy (TEM) images were obtained using a JEOL 2010D microscope from Japan, with an accelerating voltage of 200 kV.

[0047] Thermogravimetric analysis (TGA) of carbon nanotube films was performed in air using a Q600 synchronous thermal analyzer from the United States at a heating rate of 10 °C / min.

[0048] X-ray photoelectron spectroscopy was performed by ThermoFisher Scientific ESCALAB Xi+ in the United States.

[0049] Raman spectra were recorded using a ThermoFisher Raman spectrometer (USA) with an excitation wavelength of 514 nm. Conductivity was obtained using the four-probe method.

[0050] The following are specific examples.

[0051] Example 1

[0052] (1) Carbon nanotube aerogels were synthesized in a horizontal furnace using nitrogen as the carrier gas at a flow rate of 0.5 L / min. Ferrocene and thiophene were dissolved in a mixture of hexane and methanol to prepare a precursor solution. The molar ratio of ferrocene to thiophene was 5.72:1, the volume ratio of hexane to methanol was 1:4, and the molar ratio of ferrocene to hexane was 14.3 mmol:14 mL. The solution was ultrasonically treated for 30 min. The precursor solution was then injected into a reactor (a horizontal furnace at 1673 K) at a rate of 1.5 mL / min, and then carried into the high-temperature zone of the horizontal furnace by nitrogen at a flow rate of 5 L / min. Finally, the carbon nanotube aerogels were discharged from the reactor into the air by nitrogen and collected by a drum.

[0053] (2) The carbon nanotube aerogel prepared in step (1) was collected using a 10cm diameter winding cylinder, which was wrapped with sulfate paper. During the preparation process, the winding speed was adjusted to 3mm / s. A certain amount of methanol was sprayed during collection. After 30 minutes of collection, the film was peeled off the cylinder. Then, it was compressed for 5 minutes using a tablet press (MSK-2150, China) with a force of 4 tons to make the film surface smooth and dense, thus preparing CNTs. as-syn membrane;

[0054] (3) Remove the CNT from step (2) as-syn The thin film was placed in a tube furnace and heated at 1273 K in an inert atmosphere for 16 hours, followed by treatment with concentrated hydrochloric acid for 2 hours. The hydrochloric acid-treated film was then immersed in deionized water approximately three times and dried in air at room temperature. After drying, the film was densified using CSA at 423 K to form CNTs. treated film;

[0055] (4) Remove the CNT from step (3) treated The thin film was heated under nitrogen protection at a flow rate of 0.01 L / min at 973 K for CNTs. treated The film was heated for 30 minutes to obtain CNTs. treated-H / 30 Thin film refers to a flexible, lightweight thermoelectric material that is resistant to ultra-low temperatures and strong ultraviolet radiation.

[0056] (5) Performance testing: using CNT treated-H / 30 A single-legged thermoelectric power generation device composed of thin films showed no change in conductivity and Seebeck coefficient after 108 hours of irradiation with 254 / 365 nm ultraviolet light. Under a single-legged device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated carbon nanotube film was 5730 μW g. -1 .

[0057] See Figure 3 From (a) to (d), we can see that CNT as-syn The surface of the thin film is porous, with a diameter of several hundred nanometers.

[0058] The thickness is approximately 1.3 μm.

[0059] See Figure 4 From (a) to (d), we can see that CNT treated The film thickness is approximately 250 nm. (Compared to CNTs) as-syn Compared to thin film surfaces, CNTs treated The film surface is smoother and denser.

[0060] See Figure 5 From (a) to (d), we can see that CNT treated-H / 30With unheated CNTs treated Compared to thin films, the surface becomes porous and contains pores. (CNT) treated-H / 30 The film thickness also increased slightly from around 250 nm to about 300 nm, which also led to the CNT... treated The density of the film is 2.01 g / cm³. -3 Decreased to 1.16g cm -3 .

[0061] See Figure 6 It can be seen that when the temperature decreases from 300K to 100K, CNT treated-H / 30 The thin film conductivity increases, while the Seebeck coefficient decreases. At a low temperature of 100 K, the treated CNTs... treated The thin film can achieve 7.3 mW / m -1 K -2 High power factor.

[0062] See Figure 7 It can be seen that CNT treated-H / 30 When the film is stored in liquid nitrogen for about 4 hours, its conductivity and Seebeck coefficient remain almost unchanged.

[0063] See Figure 8 From (a) and (b), we can see that CNT treated-H / 30 The film can be bent freely; the sample was bent nearly 180° at a bending curvature of 3 mm in diameter. (CNT) treated-H / 30 The film exhibits excellent bending stability at ultra-low temperatures. After 1000 bends, the resistivity and Seebeck coefficient show no significant decrease or fluctuation compared to their original values.

[0064] See Figure 9 From (a) and (b), we can see that CNT treated-H / 30 After 108 hours of UV irradiation, the conductivity and Seebeck coefficient of the film remained stable. These results indicate that CNTs... treated-H / 30 The film has good UV resistance.

[0065] See Figure 10 In (a) and (b), it can be seen that the CNT has a width of 5mm and a length of 40mm. treated-H / 30 The maximum output power density of the single-leg thermoelectric device, normalized by weight and area, is 5730 μW g. -1 and 1140W m -2 .

[0066] See Figure 11 It can be seen that CNT treated-H / 30The thin film not only exhibits high thermoelectric properties at ultra-low temperatures but also possesses excellent flexibility, good mechanical strength, and low density, making it a high-performance, multifunctional, and lightweight thin film. Furthermore, the treated CNTs... treated-H / 30 The membrane also features strong water resistance, rapid temperature change resistance, and resistance to long-term ultraviolet radiation.

[0067] The results showed that CNT treated-H / 30 Thin films are ideal materials for manufacturing highly integrated thermoelectric power generation devices and have potential applications in extreme environments such as Arctic / Antarctic exploration or deep space exploration.

[0068] Example 2

[0069] (1) The preparation was the same as in Example 1. Except that the ultrasonically treated precursor liquid was injected into the reactor, the reactor temperature was changed from 1673K to 1773K.

[0070] (2) The preparation is consistent with that in Example 1.

[0071] (3) The preparation is consistent with that in Example 1.

[0072] (4) The preparation is consistent with that in Example 1.

[0073] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 5510 μW g. -1 .

[0074] Example 3

[0075] (1) The preparation was the same as in Example 1. Except that the ultrasonically treated precursor liquid was injected into the reactor, the reactor temperature was changed from 1673K to 1573K.

[0076] (2) The preparation is consistent with that in Example 1.

[0077] (3) The preparation is consistent with that in Example 1.

[0078] (4) The preparation is consistent with that in Example 1.

[0079] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4530 μW g. -1 .

[0080] Example 4

[0081] (1) The preparation is consistent with that in Example 1.

[0082] (2) The preparation is consistent with that in Example 1.

[0083] (3) The preparation is consistent with that in Example 1.

[0084] (4) The preparation was consistent with Example 1, except that CNTs were prepared at 973K. treated The film was heat-treated at 1173K.

[0085] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4930 μW g. -1 .

[0086] Example 5

[0087] (1) The preparation is consistent with that in Example 1.

[0088] (2) The preparation is consistent with that in Example 1.

[0089] (3) The preparation is consistent with that in Example 1.

[0090] (4) The preparation method was consistent with Example 1. CNTs were prepared at 973K. treated The film was heat-treated at 373K.

[0091] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4280 μW g. -1 .

[0092] Example 6

[0093] (1) The preparation is consistent with that in Example 1.

[0094] (2) The preparation is consistent with that in Example 1.

[0095] (3) The preparation is consistent with that in Example 1.

[0096] (4) The preparation was consistent with Example 1, except that CNTs were prepared at 973K. treated The heating treatment of the film was changed from 30 minutes to 10 minutes.

[0097] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 3380 μW g. -1 .

[0098] Example 7

[0099] (1) The preparation is consistent with that in Example 1.

[0100] (2) The preparation is consistent with that in Example 1.

[0101] (3) The preparation is consistent with that in Example 1.

[0102] (4) The preparation was consistent with Example 1, except that CNTs were prepared at 973K. treated The heating treatment of the film was changed from 30 minutes to 60 minutes.

[0103] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4820 μW g. -1 .

[0104] Example 8

[0105] (1) The preparation was the same as in Example 1, except that the injection rate of the ultrasonically treated precursor into the reactor was changed from 1.5 ml / min to 0.5 ml / min.

[0106] (2) The preparation is consistent with that in Example 1.

[0107] (3) The preparation is consistent with that in Example 1.

[0108] (4) The preparation is consistent with that in Example 1.

[0109] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 5540 μW g. -1 .

[0110] Example 9

[0111] (1) The preparation was the same as in Example 1, except that the injection rate of the ultrasonically treated precursor into the reactor was changed from 1.5 ml / min to 3 ml / min.

[0112] (2) The preparation is consistent with that in Example 1.

[0113] (3) The preparation is consistent with that in Example 1.

[0114] (4) The preparation is consistent with that in Example 1.

[0115] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4820 μW g. -1 .

[0116] Example 10

[0117] (1) The preparation is consistent with that in Example 1.

[0118] (2) The preparation is consistent with that in Example 1.

[0119] (3) The preparation method is consistent with Example 1, except that the prepared CNTs are... as-syn The membrane heating was changed from 1273 K in an inert atmosphere in a tube furnace to 1173 K.

[0120] (4) The preparation is consistent with that in Example 1.

[0121] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 3680 μW g. -1 .

[0122] Example 11

[0123] (1) The preparation is consistent with that in Example 1.

[0124] (2) The preparation is consistent with that in Example 1.

[0125] (3) The preparation method is consistent with Example 1, except that the prepared CNTs are... as-syn The membrane was heated at 1373 K instead of 1273 K in an inert atmosphere in a tube furnace.

[0126] (4) The preparation is consistent with that in Example 1.

[0127] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4930 μW g. -1 .

[0128] Example 12

[0129] (1) The preparation is consistent with that in Example 1.

[0130] (2) The preparation is consistent with that in Example 1.

[0131] (3) The preparation method is the same as in Example 1, except that the treatment with concentrated hydrochloric acid for 2 hours is changed to 1 hour.

[0132] (4) The preparation is consistent with that in Example 1.

[0133] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4435 μW g. -1 .

[0134] Example 13

[0135] (1) The preparation is consistent with that in Example 1.

[0136] (2) The preparation is consistent with that in Example 1.

[0137] (3) The preparation method is the same as in Example 1, except that the treatment with concentrated hydrochloric acid for 2 hours is changed to 4 hours.

[0138] (4) The preparation is consistent with that in Example 1.

[0139] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 3690 μW g. -1 .

[0140] Example 14

[0141] (1) The preparation is consistent with that in Example 1.

[0142] (2) The preparation is consistent with that in Example 1.

[0143] (3) The preparation was the same as in Example 1, except that densification at 423K was changed to 323K.

[0144] (4) The preparation is consistent with that in Example 1.

[0145] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 4670 μW g. -1 .

[0146] Example 15

[0147] (1) The preparation is consistent with that in Example 1.

[0148] (2) The preparation is consistent with that in Example 1.

[0149] (3) The preparation was the same as in Example 1, except that densification at 423K was changed to 523K.

[0150] (4) The preparation is consistent with that in Example 1.

[0151] (5) Performance Testing: After 108 hours of irradiation with 254 / 365 nm ultraviolet light, the conductivity and Seebeck coefficient of the film remained unchanged. Under a single-leg device with a heat sink temperature of 93 K and a heat source of 303 K, the weight output power density of the treated CNT film was 3895 μW g. -1 .

[0152] Example 15

[0153] (1) Carbon nanotube aerogels were synthesized in a horizontal furnace using nitrogen as the carrier gas at a flow rate of 1 L / min. Ferrocene and thiophene were dissolved in a mixture of hexane and methanol to prepare a precursor solution. The molar ratio of ferrocene to thiophene was 5.72:1, the volume ratio of hexane to methanol was 1:4, and the molar ratio of ferrocene to hexane was 14.3 mmol:14 mL. The solution was ultrasonically treated for 30 min. The precursor solution was then injected into a reactor (a horizontal furnace at 1600 K) at a rate of 1 mL / min, and then carried into the high-temperature zone of the horizontal furnace by nitrogen at a flow rate of 0.5 L / min. Finally, the carbon nanotube aerogels were discharged from the reactor into the air by nitrogen and collected by a drum.

[0154] (2) The carbon nanotube aerogel prepared in step (1) was collected using a 10cm diameter winding cylinder, which was wrapped with sulfate paper. During the preparation process, the winding speed was adjusted to 1mm / s. A certain amount of methanol was sprayed during collection. After 30 minutes of collection, the film was peeled off the cylinder. Then, it was compressed for 5 minutes using a tablet press (MSK-2150, China) with a force of 5 tons to make the film surface smooth and dense, thus preparing CNTs. as-syn membrane;

[0155] (3) Remove the CNT from step (2) as-synThe thin film was placed in a tube furnace and heated at 1210 K in an inert atmosphere for 17 h, followed by treatment with concentrated hydrochloric acid for 3 h. The hydrochloric acid-treated film was then immersed in deionized water approximately three times and dried in air at room temperature. After drying, the film was densified using CSA at 380 K to form CNTs. treated film;

[0156] (4) Remove the CNT from step (3) treated The thin film was heated under nitrogen protection at a flow rate of 0.01 L / min at 550 K for CNTs. treated The film was heated for 15 minutes to obtain the optimized CNT film, which is a flexible and lightweight thermoelectric material that is resistant to strong ultraviolet radiation at ultra-low temperatures.

[0157] Example 16

[0158] (1) Carbon nanotube aerogels were synthesized in a horizontal furnace using nitrogen as the carrier gas at a flow rate of 0.8 L / min. Ferrocene and thiophene were dissolved in a mixture of hexane and methanol to prepare a precursor solution. The molar ratio of ferrocene to thiophene was 5.72:1, the volume ratio of hexane to methanol was 1:4, and the molar ratio of ferrocene to hexane was 14.3 mmol:14 mL. The solution was ultrasonically treated for 30 min. The precursor solution was then injected into a reactor (a horizontal furnace at 1700 K) at a rate of 2 mL / min, and then carried into the high-temperature zone of the horizontal furnace by nitrogen at a flow rate of 15 L / min. Finally, the carbon nanotube aerogels were discharged from the reactor into the air by nitrogen and collected by a drum.

[0159] (2) The carbon nanotube aerogel prepared in step (1) was collected using a 10cm diameter winding cylinder, which was wrapped with sulfate paper. During the preparation process, the winding speed was adjusted to 5mm / s. A certain amount of methanol was sprayed during collection. After 30 minutes of collection, the film was peeled off the cylinder. Then, it was compressed for 10 minutes using a tablet press (MSK-2150, China) with a force of 4.5 tons to make the film surface smooth and dense, thus preparing CNTs. as-syn membrane;

[0160] (3) Remove the CNT from step (2) as-syn The thin film was placed in a tube furnace and heated at 1330 K in an inert atmosphere for 18 hours, followed by treatment with concentrated hydrochloric acid for 2 hours. The hydrochloric acid-treated film was then immersed in deionized water approximately three times and dried in air at room temperature. After drying, the film was densified using CSA at 470 K to form CNTs. treated film;

[0161] (4) Remove the CNT from step (3) treatedThe thin film was heated under nitrogen protection at a flow rate of 0.01 L / min at 870 K for CNTs. treated The film was heated for 120 minutes to obtain the optimized CNT film, which is a flexible and lightweight thermoelectric material that is resistant to strong ultraviolet radiation at ultra-low temperatures.

[0162] This invention synthesizes carbon nanotube aerogels in a nitrogen atmosphere, followed by ultrasonic treatment of the precursor solution, and then heat treatment, hydrochloric acid and chlorosulfonic acid treatment to create a flexible, lightweight thermoelectric material that maintains a thermoelectric power factor of 7.3 mW / m² at 100 K. -1 K -2 The treated carbon nanotube film exhibits high stability for over 108 hours under 254 / 365 nm ultraviolet radiation, while also possessing good flexibility and mechanical strength. Assembling the treated carbon nanotube film into a single-legged thermoelectric power generation device demonstrates its thermoelectric conversion capability at ultra-low temperatures, achieving a weight-to-weight power density as high as 5730 μW / g. -1 It is highly attractive for manufacturing highly integrated systems for specialized applications such as Arctic / Antarctic expeditions or deep space exploration.

[0163] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0164] 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 the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for preparing a flexible, lightweight thermoelectric material resistant to strong ultraviolet radiation at ultra-low temperatures, characterized in that, Includes the following steps: Macroscopic carbon nanotube films were synthesized by floating catalyst chemical vapor deposition. Macroscopic carbon nanotube films were heat-treated and treated with hydrochloric acid and chlorosulfonic acid to obtain a flexible and lightweight thermoelectric material that is resistant to strong ultraviolet radiation at ultra-low temperatures. Macroscopic carbon nanotube films are prepared through the following process: Ferrocene and thiophene were dissolved in n-hexane and methanol to obtain a precursor solution; The precursor solution was injected into a reactor at 1573–1773 K, and then nitrogen gas was used to send the precursor solution into the high-temperature zone of a horizontal furnace to obtain carbon nanotube aerogel. By pressurizing carbon nanotube aerogel, macroscopic carbon nanotube films are obtained. The molar ratio of ferrocene to thiophene is 5.72:1, the volume ratio of n-hexane to methanol is 1:4, and the volume ratio of ferrocene to n-hexane is 14.3 mmol:14 mL. A flexible, lightweight thermoelectric material resistant to strong ultraviolet radiation at ultra-low temperatures is obtained by heat treatment, hydrochloric acid treatment, and chlorosulfonic acid treatment of macroscopic carbon nanotube films, including the following steps: Macroscopic carbon nanotube films were heated at 1173–1373 K in an inert atmosphere for 16–18 h, then soaked in hydrochloric acid and dried, followed by densification treatment with chlorosulfonic acid at 323–523 K to form CNTs. treated film; CNT treated Under nitrogen protection, the thin film undergoes dedoping treatment to obtain a flexible and lightweight thermoelectric material that is resistant to strong ultraviolet radiation at ultra-low temperatures. The hydrochloric acid concentration is 36-38%, and the soaking time is 1-4 hours; The dedoping treatment was carried out at a temperature of 373K-1273K for 15-120 minutes.

2. The preparation method of the ultra-low temperature resistant, high-ultraviolet radiation-resistant flexible lightweight thermoelectric material according to claim 1, characterized in that, The temperature in the high-temperature zone is 1573–1773 K.

3. The preparation method of the ultra-low temperature resistant, strong ultraviolet radiation-resistant flexible lightweight thermoelectric material according to claim 1, characterized in that, The pressurization pressure is 4-5 tons, and the time is 5-10 minutes.

4. A flexible, lightweight thermoelectric material with resistance to strong ultraviolet radiation at ultra-low temperatures, prepared by the method according to any one of claims 1-3.

5. The flexible, lightweight thermoelectric material with ultra-low temperature resistance to strong ultraviolet radiation according to claim 4, characterized in that, In a single-leg device with a heat sink temperature of 93K and a heat source of 303K, the weight output power density of the ultra-low temperature resistant, strong ultraviolet radiation-resistant flexible and lightweight thermoelectric material reaches as high as 5730 μW g. -1 .

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