Preparation method and application of ultralow-temperature-resistant flexible rollable integrated thermoelectric device

Abstract

The invention relates to the technical field of thermoelectric energy conversion, and discloses a preparation method and application of an ultralow-temperature-resistant flexible rollable integrated thermoelectric device, and the preparation method comprises the steps: employing a floating catalyst chemical vapor deposition method to prepare a carbon nanotube CNTas-syn thin film, carrying out the purification, chlorosulfonic acid treatment and heat treatment of the carbon nanotube CNTas-syn thin film, and obtaining the ultralow-temperature-resistant flexible rollable integrated thermoelectric device. And carrying out patterning treatment on the p-type dedoped carbon nanotube CNTde-doped thin film through an n-type dopant, and carrying out cutting and packaging on the p-type dedoped carbon nanotube CNTde-doped thin film so as to obtain the monolithic integrated thermoelectric device. An integrated thermoelectric device, a heat storage tank and a self-adaptive circuit are integrated to construct a miniature thermoelectric power station, the miniature thermoelectric power station is connected with a boosting module in series to increase output voltage, and the miniature thermoelectric power station can supply power to small electronic equipment such as a timer, a light-emitting diode and global positioning system equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermoelectric energy conversion, and specifically relates to a preparation method and application of an ultra-low temperature resistant flexible rollable integrated thermoelectric device. Background Art

[0002] Thermoelectric generators (TEGs) have shown great potential for waste heat recovery due to their ability to directly convert heat into electricity through an all-solid-state structure [Chem. Rev. 120, 7399-7515 (2020); Adv. Energy Mater. 11, 2100920 (2021)]. The operation of TEGs is independent of light conditions, unlike photovoltaic devices, which rely on solar radiation [Joule 3, 2679-2686 (2019)]. This makes TEGs particularly suitable for extreme environments such as the polar night in the Arctic and Antarctic, deep space exploration [CEAS Space J. 13, 325-340 (2021)], and industrial applications such as liquefied natural gas (LNG) cooling energy recovery [Energy Proc. 105, 1932-1935 (2017)]. Thermoelectric generators have no moving parts and no liquid fluids, which further improves their reliability, reduces maintenance requirements, and enables their deployment in remote or harsh environments.

[0003] However, thermoelectric generators face two key challenges for widespread application in low-temperature environments. First, the thermoelectric performance of traditional materials drops sharply at low temperatures. Due to the suppression of carrier mobility and the enhancement of carrier freezing effects [J. Appl. Phys. 61, 1905-1909 (1987); Eng. Proc. 6, 86 (2021)], the power factor of thermoelectric materials often decreases significantly [Adv. Electron. Mater. 8, 2101125 (2022)], making thermoelectric generators inefficient in low-temperature applications. Second, at the connection between the module and the electrode, the thermal expansion mismatch between different materials will cause interface reliability issues, resulting in mechanical delamination and accelerated increase in contact resistance, which will ultimately damage the long-term performance and structural integrity of the device.

[0004] Recent advances in carbon nanotube (CNT) films and fibers have resulted in power factors (PF) approaching the theoretical power factor of a single isolated CNT [Nat. Commun. 11, 5948 (2020)]. Compared to conventional π-type thermoelectric generators, integrated thermoelectric generator designs that integrate pn modules onto a monolithic CNT film can further enhance mechanical strength and reduce internal resistance [Small 19, 2304266 (2023)]. In particular, the thermal expansion coefficient of CNTs is only one-tenth that of conventional inorganic thermoelectric materials, making them ideal materials for thermoelectric energy harvesting under extreme temperature differences.

[0005] Current low-temperature thermoelectric generators (<300 K) rely on rigid, heavy inorganic materials (e.g., bismuth telluride, which has a density of approximately 7.8 g cm -3 ) [Nano Energy 126, 109651 (2024); Energy. Convers. Manage. 62, 47-50 (2012)], while existing flexible thermoelectric materials have poor thermoelectric performance at low temperatures [Adv. Funct. Mater. 32,2111435 (2022)]. This gap highlights the urgent need to develop lightweight, flexible thermoelectric materials with high power factors, strong durability, and structural stability at low temperatures. Such materials not only increase power output density but also enable thermoelectric generators to operate reliably in environments as low as 100°C, a primary prerequisite for their applications in the Arctic and Antarctic polar night, deep space exploration, and liquefied natural gas cold energy recovery. Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a preparation method and application of an ultra-low temperature resistant flexible rollable integrated thermoelectric device, so as to obtain a lightweight flexible thermoelectric material with strong durability and structural stability at low temperatures.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for preparing a flexible, rollable, integrated thermoelectric device that is resistant to ultra-low temperatures, comprising the following steps: S1, preparation of carbon nanotubes (CNTs) using floating catalyst chemical vapor deposition as-syn film; S2, carbon nanotubes CNT as-syn The film was purified, treated with chlorosulfonic acid and heat treated to obtain p-type dedoped carbon nanotubes CNT de-doped film; S3, dedoping the p-type carbon nanotubes CNT de-dopedThe film is patterned with n-type dopants, cut and packaged to obtain an ultra-low temperature resistant, flexible and rollable integrated thermoelectric device.

[0008] A further improvement of the present invention is that, in S1, the specific method for preparing the carbon nanotube CNTas-syn film by the floating catalyst chemical vapor deposition method is: Mixing the carbon source, the catalyst and the accelerator uniformly to obtain a precursor solution; The precursor solution is fed into the high temperature zone of a horizontal tube furnace by nitrogen gas to obtain carbon nanotube aerogel; Pressurize carbon nanotube aerogel to obtain carbon nanotubes CNT as-syn film.

[0009] A further improvement of the present invention is that the temperature of the high temperature zone of the horizontal tube furnace is 1500°C.

[0010] A further improvement of the present invention is that the carbon source is a mixture of methanol and n-hexane, the catalyst is ferrocene, and the promoter is thiophene.

[0011] A further improvement of the present invention is that the volume ratio of methanol to n-hexane is (3.5-4.5): (0.5-1.5), and the concentration of ferrocene is 0.02 g mL -1 , the concentration of thiophene is 0.003mL mL -1 .

[0012] A further improvement of the present invention is that the carbon nanotubes CNT as-syn The film was purified, treated with chlorosulfonic acid and heat treated to obtain p-type dedoped carbon nanotubes CNT de-doped The specific method of film is: Annealing and hydrochloric acid treatment were used to treat carbon nanotubes CNT as-syn The film is purified, wherein the annealing treatment is carried out in a horizontal high-temperature tube furnace, nitrogen is introduced into the horizontal high-temperature tube furnace as a protective gas, the temperature is controlled at 1000°C, and the time is 16-32 hours; then, it is soaked in concentrated hydrochloric acid with a concentration of 36%-38% for 1.5-2.5 hours, and then repeatedly washed with deionized water, and finally dried in air for 1-2 hours to obtain a purified carbon nanotube film; The purified carbon nanotube film is immersed in chlorosulfonic acid for treatment for 8-12 hours at a temperature of 150-210°C to obtain dense acid-doped carbon nanotubes CNT acid-doped film; Acid doping of carbon nanotubes (CNTs) acid-dopedThe film was placed in a horizontal high-temperature tube furnace for heat treatment, nitrogen was introduced as a protective gas, the heat treatment temperature was set to 100-1000 ° C, the heat treatment time was 15-120 min, and p-type dedoped carbon nanotubes CNT were obtained. de-doped film.

[0013] A further improvement of the present invention is that the n-type dopant is added to the organic solvent, wherein the mass ratio of the n-type dopant to the organic solvent is 1-9:100, to obtain an n-type dopant solution, and the n-type dopant solution is drop-coated onto the p-type dedoped carbon nanotubes CNT de-doped The film is treated and dried to make the p-type dedoped carbon nanotubes CNT de-doped The film transforms into n-type carbon nanotubes (CNTs) n-doped film.

[0014] A further improvement of the present invention is that the n-type dopant is polyethyleneimine (PEI), the organic solvent is dimethyl sulfoxide (DMSO), and the mass ratio of the n-type dopant to the organic solvent is 1-9:100.

[0015] In a second aspect, the present invention also provides a micro thermoelectric power station, comprising a plurality of ultra-low temperature resistant flexible rollable integrated thermoelectric devices as described in any one of claims 1 to 8, wherein the plurality of integrated thermoelectric devices are connected in series and integrated with a heat storage tank and an adaptive circuit.

[0016] A further improvement of the present invention is that the number of the integrated thermoelectric devices is 15, and each monolithic integrated thermoelectric device has 6 pairs of thermoelectric legs, forming a total of 90 pairs of pn module pairs; The 15 integrated thermoelectric devices are plastic-sealed using a polyethylene terephthalate (PET) / polyimide (PI) substrate and then rolled together with a microporous foam film.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing ultra-low temperature-resistant, flexible, and rollable integrated thermoelectric devices. This method produces heat-treated carbon nanotube films with adjustable doping levels. These films exhibit excellent thermoelectric performance over a wide temperature range. This carbon nanotube film exhibits a record-breaking p-type power factor of 10.5 mW m at room temperature. -1 K -2 , it can still maintain 8.3mW m in low temperature environment (-173℃) -1 K -2levels. Even in liquid nitrogen, they exhibit excellent mechanical flexibility and robustness. Their practicality has been demonstrated by fabricating a rollable, integrated, monolithic thermoelectric device. This invention establishes a scalable model for flexible energy harvesting, combining high-performance materials engineering (through doping optimization and structural design) with sustainable applications to fully utilize industrial waste heat and cryogenic temperature differences.

[0018] Furthermore, the monolithic thermoelectric device uses selective PEI doping technology to make 6 pn modules. After being encapsulated with a low thermal conductivity polyethylene terephthalate PET / polyimide PI substrate, this compact thermoelectric generator can achieve considerable output power in both planar and curled states, at near room temperature and low temperature environments.

[0019] The present invention also provides a micro thermoelectric power station. By integrating an integrated thermoelectric device with a heat storage tank and an adaptive circuit, a micro thermoelectric power station is constructed. This power station uses hot water (86°C) or liquid nitrogen (-196°C) as a heat source, can generate an output voltage of 0.22-1.4V and a power of 4.3-175μW, and can operate continuously for more than 2.5 hours. By increasing the output voltage in series with a boost module, it can power small electronic devices such as timers, light-emitting diodes (LEDs) and global positioning system (GPS) devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the drawings are merely schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the various components of the present invention.

[0021] Figure 1 Schematic diagram of the preparation of carbon nanotube films by FCCVD, as well as purification and acid treatment; Figure 2 CNT as-syn Thin films and CNTs acid-doped SEM morphology of the film; Figure 3 CNT as-syn Thin films and CNTs acid-doped Conductivity, Seebeck coefficient and power factor of thin films; Figure 4 To obtain CNTs by heat treatment in a horizontal tube furnace de-doped Schematic diagram of the film; Figure 5 Preparation of CNTs for Example 1 de-dope Changes in the conductivity and Seebeck coefficient of the film in the temperature range of 100-368K; Figure 6 n-type dopant for CNT de-doped The film is selectively processed and cut to obtain an integrated monolithic thermoelectric device with 6 pn modules; Figure 7 The team used polyethylene terephthalate (PET) and polyimide (PI) films to encapsulate a carbon nanotube film cut into six pairs of pn modules, resulting in a planar, monolithic thermoelectric device. The team also demonstrated that multiple flexible devices connected in series can be rolled up. Figure 8 Schematic diagram of thermoelectric generator using microporous foam film rolled together to form a device; Figure 9(a) shows the temporal variation of the output voltage of the wound integrated thermoelectric generator and the temporal variation of the voltage on the hot and cold sides of the thermoelectric generator when the cup is filled with hot water or liquid nitrogen. Figure 9(b) shows the temporal variation of the output voltage of the wound integrated thermoelectric generator and the temporal variation of the temperature of the hot and cold sides of the thermoelectric generator when the cup is filled with hot water or liquid nitrogen. Figure 10 The micro-thermoelectric power station was successfully driven by a voltage amplifier at a temperature difference of about 220K, with low-power electronic devices including a digital timer and a light-emitting diode. Figure 11 To demonstrate a promising approach to powering a miniature Global Positioning System (GPS) locator (heat source temperature of 90.5°C) in a simulated polar environment (ambient temperature of -32.0°C) with hot water in a cup (temperature difference ∆T = 122.5 Kelvin). DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings.

[0023] The present invention provides a method for preparing an ultra-low temperature resistant flexible rollable integrated thermoelectric device, comprising the following steps: S1, preparation of carbon nanotubes (CNTs) using floating catalyst chemical vapor deposition as-syn film: First, methanol and n-hexane were mixed in a volume ratio of (3.5-4.5): (0.5-1.5), and then the concentration was 0.02g mL -1 The concentration of ferrocene was 0.003 mL mL -1 Thiophene is added to a mixed solution of methanol and n-hexane, wherein n-hexane serves as a carbon source, ferrocene is a catalyst, thiophene plays a promoting role, and methanol prevents the generation of a large amount of amorphous carbon. The prepared solution is then ultrasonically treated for 30-45 minutes until uniformly mixed to obtain a precursor solution. Aerogels composed of carbon nanotubes were continuously prepared using a horizontal high-temperature tube furnace: the furnace tube of the horizontal high-temperature tube furnace was a quartz tube with an inner diameter of 60 mm and a furnace temperature of 1500°C. The prepared precursor solution was injected into the furnace along with nitrogen gas, and the reaction liquid flow rate was controlled at 0.5-2.0 mL min -1 , the carrier gas flow rate is controlled at 0.5-1.5L min -1 A cylindrical tube containing gas is formed in the furnace chamber and is ejected from the furnace tube along with the gas. By optimizing the process, carbon nanotube aerogel can be blown out of the furnace tube continuously. A roller with a diameter of 10 cm and a length of 80 cm is used to collect carbon nanotube aerogel. First, sulfuric acid paper is laid on the roller, and ethanol solution is sprayed on the sulfuric acid paper. Then, the cylindrical carbon nanotube aerogel floating in the air is pulled onto the rotating roller, and with the help of alcohol, it is wound and shrunk into a narrower strip. During this process, the roller makes reciprocating motion along its length so that the cylindrical carbon nanotube aerogel can be evenly wound onto the roller, and overlapped with each other through alcohol shrinkage to form a uniform film. The capillary action of alcohol induces the self-assembly orientation of carbon nanotubes. The carbon nanotube film is removed from the roller, and then the carbon nanotube film is rolled with a roller press at a force of 4 tons for 5 minutes to make the surface of the carbon nanotube film smooth, thus obtaining carbon nanotubes CNT as-syn film.

[0024] S2, carbon nanotubes CNT as-syn The film was purified, treated with chlorosulfonic acid and heat treated to obtain p-type dedoped carbon nanotubes CNT de-doped film: The CNT prepared by S1 as-syn The film was purified and acid treated. as-syn The film undergoes a purification process, including annealing and hydrochloric acid treatment, to remove amorphous carbon and iron impurities. The annealing process is carried out in a horizontal high-temperature tube furnace with nitrogen as a protective gas at a temperature of 1000°C for 16-32 hours. The film is then soaked in 36%-38% concentrated hydrochloric acid for 1.5-2.5 hours, then repeatedly washed with deionized water, and finally dried in air for 1-2 hours to obtain the purified carbon nanotube film. The purified carbon nanotube film is immersed in chlorosulfonic acid for treatment for 8-12 hours at a temperature of 150-210°C to obtain dense acid-doped carbon nanotubes CNT acid-doped film; Acid doping of carbon nanotubes (CNTs) acid-dopedThe film was placed in a horizontal high-temperature tube furnace for heat treatment, nitrogen was introduced as a protective gas, the heat treatment temperature was set to 100-1000 ° C, the heat treatment time was 15-120 min, and p-type dedoped carbon nanotubes CNT were obtained. de-doped film.

[0025] S3, dedoping the p-type carbon nanotubes CNT de-doped The film is patterned with n-type dopants, cut, and packaged to produce an ultra-low temperature-resistant, flexible, rollable, integrated thermoelectric device: The n-type dopant polyethyleneimine PEI is added to the organic solvent DMSO, and the mass ratio of the n-type dopant to the organic solvent is 1-9:100 to obtain an n-type dopant solution. The n-type dopant solution is drop-coated on the p-type dedoped carbon nanotube CNT using a micropipette. de-doped The film is treated and then dried at normal pressure on a hot plate at 100°C for 15-90 minutes. The dopant molecules are deposited on the surface of the carbon nanotube film to obtain n-type carbon nanotubes CNT n-doped The film enables the subsequent preparation of an integrated jointless thermoelectric device on a carbon nanotube film; On a sheet of p-type dedoped carbon nanotubes CNT de-doped The film is patterned with an n-type dopant solution, and then cut and sealed to obtain an ultra-low temperature resistant, flexible, and rollable integrated thermoelectric device.

[0026] like Figure 4 As shown, the monolithic, integrated thermoelectric device has six pairs of pn legs, each 35 mm long and 5 mm wide. PEI solution is added dropwise to the series-connected thermoelectric legs for doping. Residual liquid is removed with filter paper, and the device is then dried on a hot plate at 100°C. Subsequently, the device is encapsulated with polyethylene terephthalate film and polyimide film, resulting in a planar, monolithic, integrated thermoelectric device.

[0027] The present invention also provides a micro-thermoelectric power station composed of 15 monolithic, integrated thermoelectric devices connected in series. These thermoelectric generators contain 90 pairs of pn modules, which are wrapped together with a microporous foam film. A 2L thermos cup serves as the phase change heat reservoir. This micro-thermoelectric power station increases its output voltage by connecting a boost module in series. It can power small electronic devices such as timers, light-emitting diodes (LEDs), and GPS devices.

[0028] The following are specific examples.

[0029] Example 1 Step S1, preparation of precursor solution: first, methanol and n-hexane were mixed at a volume ratio of 4:1, and then the concentration was 0.02g mL-1 The concentration of ferrocene was 0.003 mL mL -1 Thiophene is added to a mixed solution of methanol and n-hexane, and then the prepared solution is ultrasonically treated for 30 minutes until it is uniformly mixed to obtain a precursor solution; Preparation of carbon nanotube aerogel: The precursor solution was fed into the high temperature zone of a horizontal tube furnace using nitrogen. The horizontal high temperature tube furnace was a quartz tube with an inner diameter of 60 mm and a furnace temperature of 1500 °C. The prepared precursor solution was injected into the furnace along with the nitrogen. The reaction liquid flow rate was controlled at 0.8 mL min -1 , the carrier gas flow rate is controlled at 1 L min -1 , a cylindrical tube of carbon nanotubes containing gas is formed in the furnace chamber and is expelled from the furnace tube along with the gas; A roller with a diameter of 10 cm and a length of 80 cm is used to collect carbon nanotube aerogel. First, sulfuric acid paper is laid on the roller, and ethanol solution is sprayed on the sulfuric acid paper. Then, the cylindrical carbon nanotube aerogel floating in the air is pulled onto the rotating roller, and with the help of alcohol, it is wound and shrunk into a narrower strip. During this process, the roller makes reciprocating motion along its length so that the cylindrical carbon nanotube aerogel can be evenly wound onto the roller, and overlapped with each other through alcohol shrinkage to form a uniform film. The capillary action of alcohol induces the self-assembly orientation of carbon nanotubes. The carbon nanotube film is removed from the roller, and then rolled on the carbon nanotube film with a force of 4 tons for 5 minutes to make the surface of the carbon nanotube film smooth, thus obtaining carbon nanotubes CNT. as-syn The mechanism diagram of the carbon nanotube film prepared in this embodiment and the schematic diagram of purification and acid treatment are shown in FIG. Figure 1 shown.

[0030] Step S2, the carbon nanotubes CNT prepared in step S1 as-syn The film was purified and acid treated: First, the CNT as-syn The film undergoes purification treatment, which involves two steps: annealing and hydrochloric acid treatment to remove amorphous carbon and iron impurities. The annealing step is performed in a horizontal high-temperature tube furnace, protected by nitrogen, at 1000°C for 16 hours. The film is then immersed in 37% concentrated hydrochloric acid for 2 hours, washed repeatedly with deionized water, and finally dried in air to obtain the purified carbon nanotube film. The purified carbon nanotube film was immersed in chlorosulfonic acid for 12 hours at a temperature of 210°C to obtain dense acid-doped carbon nanotubes (CNTs). acid-doped film; Acid doping of carbon nanotubes (CNTs) acid-dopedThe film was placed in a horizontal high-temperature tube furnace for heat treatment, nitrogen was introduced as a protective gas, the heat treatment temperature was set to 500 ° C, the heat treatment time was 30 min, and p-type dedoped carbon nanotubes CNT were obtained. de-doped Thin film, conductivity 3.1MS m -1 , the Seebeck coefficient is 61μV K -1 .

[0031] Step S3, adding n-type dopant PEI to DMSO solvent, wherein the mass ratio of PEI to DMSO is 3:100, to obtain n-type dopant solution, and applying the n-type dopant solution to the p-type dedoped carbon nanotube CNT using a micropipette. de-doped The film was treated and then dried at normal pressure on a hot plate at 100°C for 30 minutes. The dopant molecules were deposited on the surface of the carbon nanotube film to obtain n-type carbon nanotubes CNT. n-doped film; On a p-type CNT de-doped The film is patterned with an n-type dopant solution, and then a monolithic integrated thermoelectric device is obtained by cutting and plastic packaging.

[0032] Specifically, the monolithic, integrated thermoelectric device has six pairs of pn legs, each 35 mm long and 5 mm wide. PEI solution is added dropwise to the series-connected thermoelectric legs for doping. Residual liquid is removed with filter paper, and the device is then placed on a hot plate at 100°C to dry. Next, the device is encapsulated with polyethylene terephthalate film and polyimide film, resulting in a planar, monolithic, integrated thermoelectric device.

[0033] In step S4, 15 monolithic, integrated thermoelectric devices, each containing 90 pn module pairs, are connected in series. These devices are then wrapped with a microporous foam film and a 2L thermos cup is used as a phase-change heat reservoir to form a micro-thermoelectric power station. This micro-thermoelectric power station, connected in series with a boost module to increase its output voltage, can power small electronic devices such as timers, light-emitting diodes (LEDs), and GPS devices.

[0034] See also Figure 2 From (a) and (b), we can see that CNT as-syn The surface of the film is loose and porous. After purification and acid treatment, the CNT acid-doped The voids in the film are obviously reduced, indicating that the film becomes denser.

[0035] See also Figure 3 , and CNT as-syn Compared with thin films, CNT acid-doped The film conductivity increased to 11.2MS m -1, while reducing the Seebeck coefficient to 17μV K -1 The significant improvement in conductivity makes the power factor PF higher than that of the initial carbon nanotube film, reaching 3.44mW m -1 K -2 .

[0036] See also Figure 4 , CNT acid-doped The film was heat treated in a horizontal tube furnace to obtain CNT de-doped film.

[0037] See also Figure 5 , dedoped CNT de-doped The film exhibits unique low-temperature thermoelectric properties in the temperature range of 100-368K. The electrical conductivity shows a temperature dependence similar to that of metals, increasing proportionally with increasing temperature; the Seebeck coefficient shows an inversely proportional relationship with temperature, decreasing by about 20% from 298K to 100K. It is worth noting that at 100K, the CNT de-doped The film is up to 8.3mW m -1 K -2 The power factor is maintained, showing excellent low-temperature performance retention despite the trade-off between conductivity and Seebeck coefficient.

[0038] See also Figure 6 , using CNT de-doped The film is used to make a monolithic integrated thermoelectric device containing 6 pn modules. By selective composition, PEI is added to DMSO solvent (mass ratio is 3:100) as an n-type dopant to convert the p-type dedoped carbon nanotubes CNT de-doped The film transforms into n-type carbon nanotubes (CNTs) n-doped Thin film, conductivity 3.2MS m -1 , Seebeck coefficient is -38μV K -1 This resulted in n-type modules, each thermoelectric generator (TEG) module measuring 5mm in width and 35mm in length.

[0039] See also Figure 7 , using polyethylene terephthalate PET and polyimide PI to plastic-encapsulate the carbon nanotube film cut into 6 pairs of pn modules, thereby obtaining a planar structured monolithic integrated thermoelectric device, and demonstrated that multiple flexible thermoelectric devices can be rolled up after being connected in series.

[0040] See also Figure 8 , the thermoelectric device is rolled together with the microporous foam film to form a device schematic.

[0041] Figures 9(a) and 9(b) show the temporal variations in the output voltage of the coiled thermoelectric generator and the temperature variations of the hot and cold sides of the thermoelectric generator when the cup was filled with hot water or liquid nitrogen. The system generated initial voltages of 0.43 V (86°C hot water) and 1.40 V (-196°C liquid nitrogen), respectively. Both configurations experienced a rapid voltage drop during the initial temperature difference (∆T) equilibrium phase, stabilizing at sustained output voltages of 0.25 V (hot water) and 0.32 V (liquid nitrogen), respectively, over 2.5 hours of operation.

[0042] See also Figure 10 , the micro thermoelectric power station successfully drove low-power electronic devices, including a digital timer and a light-emitting diode, through a voltage amplifier at a temperature difference of about 220K.

[0043] See also Figure 11 In a simulated polar environment (ambient temperature -32.0°C), with hot water in a cup (temperature difference ∆T = 122.5 Kelvin), a promising method for powering a miniature Global Positioning System (GPS) locator (heat source temperature 90.5°C) was demonstrated. While the current solution requires additional amplification for high-power devices, these demonstrations demonstrate the system's potential for wilderness survival applications.

[0044] These results suggest that this work establishes a scalable paradigm for flexible energy harvesting, combining high-performance materials engineering (via doping optimization and structural design) with sustainable applications that can fully exploit industrial waste heat and cryogenic temperature differences.

[0045] Example 2 The difference from Example 1 is that the heat treatment temperature in Example 2 is 500°C and the heat treatment time is 15 minutes. de-doped The film conductivity is 3.1MS m -1 , the Seebeck coefficient is 46μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.33 V (hot water at 86°C) and 1.06 V (liquid nitrogen at -196°C).

[0046] Example 3 The difference from Example 1 is that the heat treatment temperature in Example 3 is 500°C and the heat treatment time is 60 minutes. de-doped The film conductivity is 2.4MS m -1 , the Seebeck coefficient is 62μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.44 V (hot water at 86°C) and 1.43 V (liquid nitrogen at -196°C).

[0047] Example 4 The difference from Example 1 is that the heat treatment temperature in Example 4 is 500°C and the heat treatment time is 120 minutes. de-doped The film conductivity is 1.9MS m -1 , Seebeck coefficient is 65μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.46 V (86°C hot water) and 1.51 V (-196°C liquid nitrogen).

[0048] Example 5 The difference from Example 1 is that the heat treatment temperature in Example 5 is 500°C and the heat treatment time is 30 minutes. de-doped The film conductivity is 10MS m -1 , the Seebeck coefficient is 19μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.05 V (hot water at 86°C) and 0.34 V (liquid nitrogen at -196°C).

[0049] Example 6 The difference from Example 1 is that the heat treatment temperature in Example 6 is 300°C and the heat treatment time is 30 minutes. de-doped The film conductivity is 5.6MS m -1 , the Seebeck coefficient is 32μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.2 V (hot water at 86°C) and 0.7 V (liquid nitrogen at -196°C).

[0050] Example 7 The difference from Example 1 is that the heat treatment temperature in Example 7 is 700°C and the heat treatment time is 30 minutes. de-doped The film conductivity is 2.2MS m -1 , the Seebeck coefficient is 62μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.42 V (hot water at 86°C) and 1.43 V (liquid nitrogen at -196°C).

[0051] Example 8 The difference from Example 1 is that the heat treatment temperature in Example 8 is 1000°C and the heat treatment time is 30 minutes. de-doped The film conductivity is 1.7MS m -1 , the Seebeck coefficient is 66μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.46 V (86°C hot water) and 1.51 V (-196°C liquid nitrogen).

[0052] Example 9 The difference from Example 1 is that the mass ratio of PEI to DMSO in Example 9 is 1:100. n-doped The film conductivity is 3.3MS m -1 , the Seebeck coefficient is -37μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.41 V (hot water at 86°C) and 1.36 V (liquid nitrogen at -196°C).

[0053] Example 10 The difference from Example 1 is that the mass ratio of PEI to DMSO in Example 10 is 5:100. n-doped The film conductivity is 3.4MS m -1 , the Seebeck coefficient is -36μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.41 V (hot water at 86°C) and 1.34 V (liquid nitrogen at -196°C).

[0054] Example 11 The difference from Example 1 is that the mass ratio of PEI to DMSO in Example 11 is 7:100. n-doped The film conductivity is 3.7MS m -1 , Seebeck coefficient is -34μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.38 V (hot water at 86°C) and 1.26 V (liquid nitrogen at -196°C).

[0055] Example 12 The difference from Example 1 is that the mass ratio of PEI to DMSO in Example 12 is 9:100. n-doped The film conductivity is 3.8MS m -1 , the Seebeck coefficient is -31μV K -1 The micro-thermoelectric power station generated an initial voltage of 0.35 V (hot water at 86°C) and 1.16 V (liquid nitrogen at -196°C).

[0056] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an ultra-low temperature resistant flexible rollable integrated thermoelectric device, characterized in that: The following steps are involved: S1, preparation of carbon nanotubes (CNTs) using floating catalyst chemical vapor deposition as-syn film; S2, carbon nanotubes CNT as-syn The film was purified, treated with chlorosulfonic acid and heat treated to obtain p-type dedoped carbon nanotubes CNT de-doped film; S3, dedoping the p-type carbon nanotubes CNT de-doped The film is patterned with n-type dopants, cut and packaged to obtain an ultra-low temperature resistant, flexible and rollable integrated thermoelectric device.

2. The method for preparing a flexible and rollable integrated thermoelectric device resistant to ultra-low temperatures according to claim 1, characterized in that: In S1, the specific method for preparing the carbon nanotube CNTas-syn film by using the floating catalyst chemical vapor deposition method is: Mixing the carbon source, the catalyst and the accelerator uniformly to obtain a precursor solution; The precursor solution is fed into the high temperature zone of a horizontal tube furnace by nitrogen gas to obtain carbon nanotube aerogel; Pressurize carbon nanotube aerogel to obtain carbon nanotubes CNT as-syn film.

3. The method for preparing a flexible and rollable integrated thermoelectric device resistant to ultra-low temperatures according to claim 2, characterized in that: The temperature of the high temperature zone of the horizontal tube furnace is 1500°C.

4. The method for preparing a flexible and rollable integrated thermoelectric device resistant to ultra-low temperatures according to claim 2, characterized in that: The carbon source is a mixture of methanol and n-hexane, the catalyst is ferrocene, and the promoter is thiophene.

5. The method for preparing a flexible and rollable integrated thermoelectric device resistant to ultra-low temperatures according to claim 4, characterized in that: The volume ratio of methanol to n-hexane is (3.5-4.5): (0.5-1.5), and the concentration of ferrocene is 0.02 g mL -1 , the concentration of thiophene is 0.003mL mL -1 .

6. The method for preparing a flexible and rollable integrated thermoelectric device resistant to ultra-low temperatures according to claim 1, characterized in that: The carbon nanotubes CNT as-syn The film was purified, treated with chlorosulfonic acid and heat treated to obtain p-type dedoped carbon nanotubes CNT de-doped The specific method of film is: Annealing and hydrochloric acid treatment were used to treat carbon nanotubes CNT as-syn The film is purified, wherein the annealing treatment is carried out in a horizontal high-temperature tube furnace, nitrogen is introduced into the horizontal high-temperature tube furnace as a protective gas, the temperature is controlled at 1000°C, and the time is 16-32 hours; then, it is soaked in concentrated hydrochloric acid with a concentration of 36%-38% for 1.5-2.5 hours, and then repeatedly washed with deionized water, and finally dried in air for 1-2 hours to obtain a purified carbon nanotube film; The purified carbon nanotube film is immersed in chlorosulfonic acid for treatment for 8-12 hours at a temperature of 150-210°C to obtain dense acid-doped carbon nanotubes CNT acid-doped film; Acid doping of carbon nanotubes (CNTs) acid-doped The film was placed in a horizontal high-temperature tube furnace for heat treatment, nitrogen was introduced as a protective gas, the heat treatment temperature was set to 100-1000 ° C, the heat treatment time was 15-120 min, and p-type dedoped carbon nanotubes CNT were obtained. de-doped film.

7. The method for preparing a flexible and rollable integrated thermoelectric device resistant to ultra-low temperatures according to claim 1, characterized in that: The n-type dopant is added to the organic solvent, wherein the mass ratio of the n-type dopant to the organic solvent is 1-9:100, to obtain an n-type dopant solution, and the n-type dopant solution is drop-coated onto the p-type dedoped carbon nanotubes CNT de-doped The film is treated and dried to make the p-type dedoped carbon nanotubes CNT de-doped The film transforms into n-type carbon nanotubes (CNTs) n-doped film.

8. The method for preparing a flexible and rollable integrated thermoelectric device resistant to ultra-low temperatures according to claim 1, characterized in that: The n-type dopant is polyethyleneimine (PEI), the organic solvent is dimethyl sulfoxide (DMSO), and the mass ratio of the n-type dopant to the organic solvent is 1-9:

100.

9. A micro thermal power station, characterized in that: The invention comprises a plurality of ultra-low temperature resistant flexible rollable integrated thermoelectric devices according to any one of claims 1 to 8, wherein the plurality of integrated thermoelectric devices are connected in series and integrated with a heat storage tank and an adaptive circuit.

10. The micro thermal power station according to claim 9, characterized in that: The number of the integrated thermoelectric devices is 15, and each monolithic integrated thermoelectric device has 6 pairs of thermoelectric legs, forming a total of 90 pairs of pn module pairs; The 15 integrated thermoelectric devices are plastic-sealed using a polyethylene terephthalate (PET) / polyimide (PI) substrate and then rolled together with a microporous foam film.

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