Wearable thermoelectric generator with self-healing function and preparation method thereof

Abstract

According to the wearable thermoelectric generator with the self-healing function and the preparation method of the wearable thermoelectric generator, the aluminum chloride dissolving pulp is adopted as a doping agent, and the thermoelectric performance of the two-dimensional transition metal disulfide nanosheet is improved through electronic structure regulation and control. As S atoms on the surfaces of the disulfides are negatively charged, and aluminum ions are positively charged, and the positive and negative charges attract each other, the aluminum ions bind adjacent different disulfides together, so that the disulfides have better electrical properties. Even if a small amount of aluminum chloride dissolved pulp is added, the conductivity and Seebeck coefficient can be simultaneously improved, the thermoelectric power is improved by 14 times compared with that before modification, and better stability is kept in temperature and relative humidity. And forming the modified n / p type thermoelectric material into a flexible thermoelectric device with a self-healing characteristic. The output voltage of the device reaches about 15mV by using the heat of a human body, which is obviously improved compared with that of the existing two-dimensional transition metal sulfide-based thermoelectric wearable device, and an important step is realized for the short-step practical application of the two-dimensional transition metal sulfide-based thermoelectric wearable device.

Description

Technical Field

[0001] The present invention relates to the technical field of wearable thermoelectric devices, and in particular to a wearable thermoelectric generator with a self-healing function and a preparation method thereof. Background Art

[0002] In recent years, various wearable electronic devices, such as smart watches, smart glasses and smart clothing, have become common products in daily life, and lightweight and flexible energy supply systems are the key to ensure their normal operation. Self-powered systems are environmentally friendly and can continuously convert energy, making full use of the heat energy of the human body and the environment.

[0003] Thermoelectric materials can convert thermal energy into electrical energy. Their performance is defined by the infinite dimension ZT: ZT = (α 2 σT) / κ, where α is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature, and κ is the thermal conductivity. Thermoelectric materials for human body heat conversion must meet the requirements of being close to room temperature and flexible. At present, the most commonly used thermoelectric materials are bismuth telluride-based materials and organic conductive polymers, but the former are rigid and toxic, and the latter have low thermoelectric performance.

[0004] Two-dimensional transition metal sulfides are considered to be ideal room-temperature thermoelectric materials due to their high carrier mobility and good flexibility caused by the quantum confinement effect. The thermoelectric powers of representative two-dimensional transition metal sulfide materials MoS2 and TiS2 reach 8.5 and 3.7 mW / mK respectively. 2 , which can be compared with bismuth telluride-based materials.

[0005] At present, the main methods for regulating the electronic structure of two-dimensional transition metal sulfides to improve thermoelectric performance include defect engineering, alloying and surface modification, among which surface modification has the advantages of mild process conditions, strong controllability and easy large-scale preparation. For example, Wang Yifeng et al. mixed MoS2 powder and TiS2 powder prepared by ball milling in patent authorization number CN105226180B to improve their final thermoelectric performance, but this method is only suitable for the preparation of thermoelectric materials and is difficult to be compatible with flexible wearable processes. Summary of the invention

[0006] The present invention provides a wearable thermoelectric generator with self-healing function and a preparation method thereof, the purpose of which is to solve the above-mentioned problems existing in the background technology.

[0007] In order to achieve the above-mentioned object, an embodiment of the present invention provides a wearable thermoelectric generator with self-healing function and a preparation method thereof, wherein the preparation method uses aluminum chloride slurry as a dopant, and improves the thermoelectric properties of MoS2 nanosheets and TiS2 nanosheets through electronic structure regulation. The mechanism of action is to utilize the negatively charged S atoms on the surface of MoS2 and TiS2 nanosheets, and the positively charged aluminum ions in Lewis acid solutions (such as aluminum chloride), so that the positive and negative attract each other, so that the aluminum ions bind adjacent MoS2 or TiS2 together, thereby having better electrical properties. Even if a small amount of AlCl3 slurry is added, its electrical conductivity and Seebeck coefficient are improved at the same time, the thermoelectric power is increased by 14 times compared with that before modification, and better stability is maintained at temperature and relative humidity. The modified TiS2 nanosheets are then used as n-type thermoelectric materials, and the modified MoS2 nanosheets are used as p-type thermoelectric materials to prepare flexible thermoelectric devices with self-healing properties. Using human body heat, the device achieves an output voltage of about 15mV, a significant improvement over existing two-dimensional transition metal sulfide-based thermoelectric wearable devices and an important step towards its near-practical application.

[0008] An embodiment of the present invention provides a wearable thermoelectric generator with a self-healing function, comprising a substrate and a p / n type thermoelectric unit composited on the substrate; the p / n type thermoelectric unit comprises one or more groups of p / n type thermoelectric thin film materials connected in series and in parallel;

[0009] There are gaps between the groups of the plurality of series-parallel p / n-type thermoelectric thin film materials; the p-type thermoelectric thin film materials and the n-type thermoelectric thin film materials are alternately arranged; the p-type thermoelectric thin film materials and the n-type thermoelectric thin film materials are connected by conductive materials;

[0010] The substrate comprises a flexible substrate film layer; the substrate is made of at least one of polydimethylsiloxane, styrene-based thermoplastic elastomer and polyimide;

[0011] The p / n type thermoelectric unit adopts a thin film material made of two-dimensional transition metal disulfide nanosheets doped with Lewis acid solution;

[0012] The two-dimensional transition metal disulfide nanosheets include at least one of MoS2, TiS2, WS2, MoSe2, and WSe2;

[0013] The Lewis acid solution includes at least one of aluminum trichloride, boron trifluoride, sulfur trioxide, and ferric bromide.

[0014] Preferably, the p / n type thermoelectric unit adopts a thin film material made of two-dimensional TiS2 nanosheets and MoS2 nanosheets doped with Lewis acid solution.

[0015] Preferably, the p / n type thermoelectric unit adopts a thin film material made of two-dimensional TiS2 nanosheets and MoS2 nanosheets doped with AlCl3 solution.

[0016] Preferably, the concentration of the Lewis acid solution is 1 mmol / L.

[0017] Preferably, the dimensions of the p / n type thermoelectric unit are: 2 cm in length and 0.5 cm in width; and the spacing between the p / n type thermoelectric units is 0.1-1 cm.

[0018] Preferably, the doping process adopts a lithium intercalation stripping method or an ultrasonic dispersion method.

[0019] Preferably, the nanosheet has a diameter of 1.5 cm.

[0020] Preferably, the conductive material includes at least one of silver paste, silver wire, liquid metal, graphene, carbon nanotube and copper nanowire.

[0021] Preferably, the substrate has a thickness of several micrometers.

[0022] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned wearable thermoelectric generator with self-healing function, comprising the following steps:

[0023] S1: Preparation of mold: According to the size and spacing of the thermoelectric unit, the flexible substrate is processed into the required shape and size through mechanical processing;

[0024] S2: Preparation of flexible substrate: fully mix the substrate and curing agent in a mass ratio of 10:1 and pour into the mold in step S1, cure at 65°C for 4 hours, and cut into suitable sizes after cooling;

[0025] S3: Preparation of p / n type thermoelectric thin film material: preparing a two-dimensional transition metal disulfide nanosheet dispersion by lithium intercalation stripping method, and then doping the two-dimensional transition metal disulfide nanosheet dispersion with Lewis acid solution to prepare a p / n type thermoelectric thin film material;

[0026] S4: Attach the p / n type thermoelectric thin film material to the flexible substrate and arrange them crosswise in sequence, and then connect them with conductive materials to form electrodes, so that each thermoelectric unit forms a series-parallel structure.

[0027] Preferably, step S3 specifically includes the following process:

[0028] Step 1: Prepare TiS2 nanosheet dispersion using lithium intercalation stripping method:

[0029] Take TiS2 powder, n-butyl lithium solution and n-hexane solution and stir them continuously under nitrogen environment to fully mix them to complete the lithium intercalation process to synthesize Li x TiS2; the precipitate in the above solution is filtered and washed with n-hexane several times to remove excess n-butyl lithium, and then the precipitate is placed in deionized water for stripping, and combined with ultrasonic assisted stripping, the ultrasonic power is 200W, and the time is 5 minutes. After the stripping is completed, the obtained solution is centrifuged at a speed of 10,000 rpm for several times to remove Li atoms and unstripped materials, and a high-quality ultrathin TiS2 nanosheet dispersion can be obtained.

[0030] Step 2: Prepare MoS2 nanosheet dispersion using lithium intercalation stripping method:

[0031] (1) MoS2 powder and n-butyl lithium solution are added to n-hexane and stirred at room temperature in a nitrogen environment in a glove box to fully mix;

[0032] (2) The obtained mixed dispersion was placed in a centrifuge and centrifuged at 10,000 rpm for 10 minutes, the precipitate after centrifugation was collected, and the precipitate was dispersed in n-hexane and centrifuged at 10,000 rpm for 10 minutes and the precipitate was collected. This operation was repeated 3 times to remove excess n-butyl lithium.

[0033] (3) adding the washed precipitate into deionized water, placing it into a cell crusher and ultrasonically exfoliating it at room temperature and 600 W power for 60 minutes to obtain a MoS2 nanosheet dispersion;

[0034] (4) The obtained MoS2 nanosheet dispersion was placed in a centrifuge again and centrifuged at 10,000 rpm for 5 minutes to remove the unpeeled MoS2 precipitate. The operation was repeated 3 times to obtain a well-dispersed MoS2 nanosheet dispersion.

[0035] Step 3: Preparation of AlCl3-doped TiS2 nanosheets and AlCl3-doped MoS2 nanosheets assembled thermoelectric thin films:

[0036] The TiS2 or MoS2 nanosheet dispersion and a certain volume of AlCl3 solution are uniformly added to the filtration device at the same time (the two solutions cannot be mixed in advance, otherwise the nanosheets will agglomerate) for vacuum filtration. After completion, the obtained film is vacuum dried at room temperature to remove residual moisture to complete the preparation.

[0037] Preferably, step S4 specifically includes the following process:

[0038] The AlCl3-modified TiS2 nanosheet assembly film and the modified MoS2 nanosheet assembly film are attached face to face on the PDMS substrate, and the PDMS film is torn off after drying. At this time, the thermoelectric film has been transferred to the PDMS. Then, arrays of AlCl3-modified TiS2 nanosheet assembly films and modified MoS2 nanosheet assembly films are attached to the PDMS substrate and arranged crosswise in sequence, and connected to each other with silver glue and silver wires.

[0039] The above scheme of the present invention has the following beneficial effects:

[0040] 1. The present invention uses a surface modification method to regulate the electronic structure of TiS2 nanosheets using a small amount of AlCl3 solution. By regulating the amount of AlCl3 solution, the conductivity and Seebeck coefficient can be simultaneously improved. This phenomenon breaks through the problem of mutual restriction between conductivity and Seebeck coefficient in traditional thermoelectric materials.

[0041] 2. The present invention improves the environmental adaptability and stability of the material. Through surface modification, TiS2 film and MoS2 film show remarkable performance stability under different temperature and relative humidity conditions, which significantly expands the application scope of these materials in complex environments.

[0042] 3. The flexible thermoelectric device designed and prepared by the present invention exhibits self-healing properties. When the device breaks after being stretched, the removal of external force can restore it to its original shape and regenerate thermoelectric voltage. In addition, after the device is repeatedly bent 1,000 times, the power output only decays by about 12%, showing excellent mechanical stability, meeting the requirements of wearable devices for flexibility and durability.

[0043] 4. Different from traditional doping, defect engineering and other technologies, the present invention adopts surface modification technology with mild reaction conditions, strong controllability and suitable for large-scale preparation, providing an economical and efficient solution for the practical application of high-performance thermoelectric materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 Schematic diagram of the preparation process of two-dimensional transition metal disulfide nanosheets according to an embodiment of the present invention;

[0046] Figure 2 is a scanning electron microscope photograph of a two-dimensional TiS2 nanosheet prepared in an embodiment of the present invention;

[0047] Figure 3 is a scanning electron microscope photograph of a two-dimensional MoS2 nanosheet prepared in an embodiment of the present invention;

[0048] Figure 4 It is a schematic diagram of the process of preparing a two-dimensional transition metal disulfide flexible thermoelectric film according to an embodiment of the present invention;

[0049] Figure 5 This is a thermoelectric performance diagram of the n-type two-dimensional TiS2 nanosheet thermoelectric film prepared in an embodiment of the present invention, from left to right are the conductivity, Seebeck coefficient and power factor of different AlCl3 doping amounts;

[0050] Figure 6 This is a thermoelectric performance diagram of a p-type two-dimensional MoS2 nanosheet thermoelectric film prepared in an embodiment of the present invention, from left to right, the conductivity, Seebeck coefficient and power factor of different AlCl3 doping amounts;

[0051] Figure 7 It is a schematic diagram of transferring a two-dimensional transition metal disulfide flexible thermoelectric film prepared by filtration to a flexible stretchable PDMS substrate in an embodiment of the present invention;

[0052] Figure 8 is a photograph of a thermoelectric power generation device composed of a piece of n-type two-dimensional TiS2 nanosheet thermoelectric film and a piece of p-type two-dimensional MoS2 nanosheet thermoelectric film connected in series in an embodiment of the present invention;

[0053] Fig. 9 The thermoelectric power generation device of the embodiment of the present invention is composed of a plurality of n-type two-dimensional TiS2 nanosheet thermoelectric films and a plurality of p-type two-dimensional MoS2 nanosheet thermoelectric films connected in series;

[0054] Fig.10 This is a performance demonstration diagram of the thermoelectric power generation device of an embodiment of the present invention that is stretchable and can self-heal and restore. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0056] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0057] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0058] In view of the existing problems, the present invention provides a wearable thermoelectric generator with a self-healing function, comprising a substrate and a p / n type thermoelectric unit composited on the substrate; the p / n type thermoelectric unit comprises one or more groups of p / n type thermoelectric thin film materials connected in series and in parallel;

[0059] There are gaps between the groups of the plurality of series-parallel p / n-type thermoelectric thin film materials; the p-type thermoelectric thin film materials and the n-type thermoelectric thin film materials are alternately arranged; the p-type thermoelectric thin film materials and the n-type thermoelectric thin film materials are connected by conductive materials;

[0060] The substrate comprises a flexible substrate film layer; the substrate is made of at least one of polydimethylsiloxane, styrene-based thermoplastic elastomer and polyimide;

[0061] The p / n type thermoelectric unit adopts a thin film material made of two-dimensional transition metal disulfide nanosheets doped with Lewis acid solution;

[0062] The two-dimensional transition metal disulfide nanosheets include at least one of MoS2, TiS2, WS2, MoSe2, and WSe2;

[0063] The Lewis acid solution includes at least one of aluminum trichloride, boron trifluoride, sulfur trioxide, and ferric bromide.

[0064] Preferably, the p / n type thermoelectric unit adopts a thin film material made of two-dimensional TiS2 nanosheets and MoS2 nanosheets doped with Lewis acid solution.

[0065] Preferably, the p / n type thermoelectric unit adopts a thin film material made of two-dimensional TiS2 nanosheets and MoS2 nanosheets doped with AlCl3 solution.

[0066] Preferably, the concentration of the Lewis acid solution is 1 mmol / L.

[0067] Preferably, the dimensions of the p / n type thermoelectric unit are: 2 cm in length and 0.5 cm in width; and the spacing between the p / n type thermoelectric units is 0.1-1 cm.

[0068] Preferably, the doping process adopts a lithium intercalation stripping method or an ultrasonic dispersion method.

[0069] Preferably, the nanosheet has a diameter of 1.5 cm.

[0070] Preferably, the conductive material includes at least one of silver paste, silver wire, liquid metal, graphene, carbon nanotube and copper nanowire.

[0071] Preferably, the substrate has a thickness of several micrometers.

[0072] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned wearable thermoelectric generator with self-healing function, comprising the following steps:

[0073] S1: Preparation of mold: According to the size and spacing of the thermoelectric unit, the flexible substrate is processed into the required shape and size through mechanical processing;

[0074] S2: Preparation of flexible substrate: fully mix the substrate and curing agent in a mass ratio of 10:1, pour into the mold in step S1, cure at 65°C for 4 hours, and cut into suitable sizes after cooling;

[0075] S3: Preparation of p / n type thermoelectric thin film material: preparing a two-dimensional transition metal disulfide nanosheet dispersion by lithium intercalation stripping method, and then doping the two-dimensional transition metal disulfide nanosheet dispersion with Lewis acid solution to prepare a p / n type thermoelectric thin film material;

[0076] S4: Attach the p / n type thermoelectric thin film material to the flexible substrate and arrange them crosswise in sequence, and then connect them with conductive materials to form electrodes, so that each thermoelectric unit forms a series-parallel structure.

[0077] Preferably, step S3 specifically includes the following process:

[0078] Step 1: Prepare TiS2 nanosheet dispersion using lithium intercalation stripping method:

[0079] Take TiS2 powder, n-butyl lithium solution and n-hexane solution and stir them continuously under nitrogen environment to fully mix them to complete the lithium intercalation process to synthesize Li x TiS2; the precipitate in the above solution is filtered and washed with n-hexane several times to remove excess n-butyl lithium, and then the precipitate is placed in deionized water for stripping, and combined with ultrasonic assisted stripping, the ultrasonic power is 200W, and the time is 5 minutes. After the stripping is completed, the obtained solution is centrifuged at a speed of 10,000 rpm for several times to remove Li atoms and unstripped materials, and a high-quality ultrathin TiS2 nanosheet dispersion can be obtained.

[0080] Step 2: Prepare MoS2 nanosheet dispersion using lithium intercalation stripping method:

[0081] (1) MoS2 powder and n-butyl lithium solution are added to n-hexane and stirred at room temperature in a nitrogen environment in a glove box to fully mix;

[0082] (2) The obtained mixed dispersion was placed in a centrifuge and centrifuged at 10,000 rpm for 10 minutes, the precipitate after centrifugation was collected, and the precipitate was dispersed in n-hexane and centrifuged at 10,000 rpm for 10 minutes and the precipitate was collected. This operation was repeated 3 times to remove excess n-butyl lithium.

[0083] (3) adding the washed precipitate into deionized water, placing it into a cell crusher and ultrasonically exfoliating it at room temperature and 600 W power for 60 minutes to obtain a MoS2 nanosheet dispersion;

[0084] (4) The obtained MoS2 nanosheet dispersion was placed in a centrifuge again and centrifuged at 10,000 rpm for 5 minutes to remove the unpeeled MoS2 precipitate. The operation was repeated 3 times to obtain a well-dispersed MoS2 nanosheet dispersion.

[0085] Step 3: Preparation of AlCl3-doped TiS2 nanosheets and AlCl3-doped MoS2 nanosheets assembled thermoelectric thin films:

[0086] The TiS2 or MoS2 nanosheet dispersion and a certain volume of AlCl3 solution are uniformly added to the filtration device at the same time (the two solutions cannot be mixed in advance, otherwise the nanosheets will agglomerate) for vacuum filtration. After completion, the obtained film is vacuum dried at room temperature to remove residual moisture to complete the preparation.

[0087] Preferably, step S4 specifically includes the following process:

[0088] The AlCl3-modified TiS2 nanosheet assembly film and the modified MoS2 nanosheet assembly film are attached face to face on the PDMS substrate, and the PDMS film is torn off after drying. At this time, the thermoelectric film has been transferred to the PDMS. Then, arrays of AlCl3-modified TiS2 nanosheet assembly films and modified MoS2 nanosheet assembly films are attached to the PDMS substrate and arranged crosswise in sequence, and connected to each other with silver glue and silver wires.

[0089] The following is a detailed description of the present invention through specific examples. The following curing agent uses Corning 184 curing agent.

[0090] Example

[0091] A method for preparing a wearable thermoelectric generator with self-healing function comprises the following steps:

[0092] S1: Preparation of mold: According to the size and spacing of the thermoelectric unit, the flexible substrate is processed into the required shape and size through mechanical processing;

[0093] S2: Preparation of flexible substrate: PDMS and curing agent were fully mixed in a mass ratio of 10:1 and poured into the mold in step S1, cured at 65°C for 4 hours, and cut into suitable sizes after cooling;

[0094] S3: Preparation of p / n-type thermoelectric thin film materials: Preparation of two-dimensional transition metal disulfide nanosheet dispersion by lithium intercalation exfoliation method;

[0095] S4: Attach the p / n type thermoelectric thin film material to the flexible substrate and arrange them crosswise in sequence, and then connect them with conductive materials to form electrodes, so that each thermoelectric unit forms a series-parallel structure.

[0096] Wherein, step S3 specifically includes the following process:

[0097] Step 1: Prepare TiS2 nanosheet dispersion using lithium intercalation stripping method. See the schematic diagram of the process. Figure 1 :

[0098] 0.2 g TiS2 powder, 2 mL n-butyl lithium solution and 8 mL n-hexane solution were stirred continuously for 18 hours under nitrogen environment to fully mix them and complete the lithium intercalation process to synthesize Li x TiS2. The precipitate in the above solution was filtered and washed several times with n-hexane to remove excess n-butyl lithium. The precipitate was then placed in deionized water for stripping and ultrasonic assisted stripping was performed with an ultrasonic power of 200 W for 5 minutes. After the stripping was completed, the resulting solution was centrifuged several times at 10,000 rpm to remove Li atoms and unstripped materials, and a high-quality ultrathin TiS2 nanosheet dispersion was obtained. The optical photograph of the TiS2 nanosheet is shown in Figure 2 .

[0099] Step 2: Prepare MoS2 nanosheet dispersion using lithium intercalation stripping method. See the schematic diagram of the process. Figure 1 :

[0100] (1) 0.6 g MoS2 powder and 6 mL n-butyl lithium solution were added to 24 mL n-hexane and stirred at room temperature for 48 hours in a glove box under nitrogen atmosphere;

[0101] (2) The obtained mixed dispersion was placed in a centrifuge and centrifuged at 10,000 rpm for 10 minutes, the precipitate after centrifugation was collected, and the precipitate was dispersed in n-hexane and centrifuged at 10,000 rpm for 10 minutes and the precipitate was collected. This operation was repeated 3 times to remove excess n-butyl lithium.

[0102] (3) adding the washed precipitate into 400 mL of deionized water, placing it into a cell crusher and ultrasonically exfoliating it at room temperature and 600 W power for 60 minutes to obtain a MoS2 nanosheet dispersion;

[0103] (4) The obtained dispersion was centrifuged again at 10,000 rpm for 5 minutes to remove the unpeeled MoS2 precipitate. The operation was repeated 3 times to obtain a well-dispersed MoS2 nanosheet dispersion. The optical photograph of the MoS2 nanosheet is shown in FIG. Figure 3 .

[0104] Step 3: Preparation of AlCl3-doped TiS2 nanosheets and AlCl3-doped MoS2 nanosheets assembled thermoelectric thin films, the process diagram is shown in Figure 4 :

[0105] 5mL of TiS2 or MoS2 nanosheet dispersion and a certain volume of 1mmol / LAlCl3 solution are uniformly added to the filtration device at the same time (the two solutions cannot be mixed in advance, otherwise it will cause the nanosheets to agglomerate) and vacuum filtered. After completion, the obtained film is vacuum dried at room temperature to remove residual moisture and the preparation is completed. Changing the AlCl3 solution can obtain the thermoelectric properties of the thermoelectric film at different doping concentrations. The specific performance is shown in Figure 5 and Figure 6 .

[0106] Wherein, step S4 specifically includes the following process:

[0107] The thermoelectric film was transferred to the stretchable PDMS substrate as follows. The process diagram is shown in Figure 7 :

[0108] Preparation of flexible PDMS substrate: Mix PDMS and curing agent in a mass ratio of 10:1 and pour into a specific mold. Curing at 65°C for 4 hours, and cutting into appropriate size after cooling.

[0109] The AlCl3-modified TiS2 nanosheet assembled film and the modified MoS2 nanosheet assembled film are attached face to face on the PDMS substrate. After drying, the PDMS film is torn off, and the thermoelectric film has been transferred to the PDMS.

[0110] Attach the array of 0.5×2cm-sized AlCl3-modified TiS2 nanosheets and modified MoS2 nanosheets to the PDMS substrate and arrange them crosswise in sequence, and connect them with silver glue and silver wire. The upper layer of the film is encapsulated with PDMS to isolate the air, and half of it is covered with thermal insulation tape to complete the preparation of the thermoelectric wristband. Figure 8 , multiple groups of p / n type thermoelectric thin film materials are connected in series Fig. 9 .

[0111] The self-healing performance of the above thermoelectric thin film material was tested. When the device was stretched and broken, the external force could be removed to restore it to its original shape and regenerate thermoelectric voltage. In addition, after the device was repeatedly bent 1,000 times, the power output only decayed by about 12%, showing excellent mechanical stability and meeting the requirements of wearable devices for flexibility and durability. Its stretchable and self-healing performance is shown in the following figure. Fig.10 shown.

[0112] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A wearable thermoelectric generator with self-healing function, characterized in that: It comprises a substrate and a p / n type thermoelectric unit composited on the substrate; the p / n type thermoelectric unit comprises one or more groups of p / n type thermoelectric thin film materials connected in series and in parallel; There are gaps between the groups of the plurality of series-parallel p / n-type thermoelectric thin film materials; the p-type thermoelectric thin film materials and the n-type thermoelectric thin film materials are alternately arranged; the p-type thermoelectric thin film materials and the n-type thermoelectric thin film materials are connected by conductive materials; The substrate comprises a flexible substrate film layer; the substrate is made of at least one of polydimethylsiloxane, styrene-based thermoplastic elastomer and polyimide; The p / n type thermoelectric unit adopts a thin film material made of two-dimensional transition metal disulfide nanosheets doped with Lewis acid solution; The two-dimensional transition metal disulfide nanosheets include at least one of MoS2, TiS2, WS2, MoSe2, and WSe2; The Lewis acid solution includes at least one of aluminum trichloride, boron trifluoride, sulfur trioxide, and ferric bromide.

2. The wearable thermoelectric generator with self-healing function according to claim 1, characterized in that: The p / n type thermoelectric unit adopts a thin film material made of two-dimensional TiS2 nanosheets and MoS2 nanosheets doped with Lewis acid solution.

3. The wearable thermoelectric generator with self-healing function according to claim 2, characterized in that: The p / n type thermoelectric unit adopts a thin film material made of two-dimensional TiS2 nanosheets and MoS2 nanosheets doped with AlCl3 solution.

4. The wearable thermoelectric generator with self-healing function according to claim 3, characterized in that: The dimensions of the p / n type thermoelectric unit are: 2 cm in length and 0.5 cm in width; the spacing between the p / n type thermoelectric units is 0.1-1 cm.

5. The wearable thermoelectric generator with self-healing function according to claim 4, characterized in that: The concentration of the Lewis acid solution is 1 mmol / L.

6. The wearable thermoelectric generator with self-healing function according to claim 1, characterized in that: The doping process adopts a lithium intercalation stripping method or an ultrasonic dispersion method.

7. The wearable thermoelectric generator with self-healing function according to claim 1, characterized in that: The diameter of the nanosheet is 1.5 cm.

8. The wearable thermoelectric generator with self-healing function according to claim 1, characterized in that: The conductive material includes at least one of silver glue, silver wire, liquid metal, graphene, carbon nanotube and copper nanowire.

9. The method for preparing a wearable thermoelectric generator with self-healing function according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Preparation of mold: According to the size and spacing of the thermoelectric unit, the flexible substrate is processed into the required shape and size through mechanical processing; S2: Preparation of flexible substrate: The substrate and curing agent are fully mixed in a mass ratio of 10:1 and poured into the mold in step S1, cured at 65°C for 4 hours, and cut into suitable sizes after cooling; S3: Preparation of p / n type thermoelectric thin film material: preparing a two-dimensional transition metal disulfide nanosheet dispersion by lithium intercalation stripping method, and then doping the two-dimensional transition metal disulfide nanosheet dispersion with Lewis acid solution to prepare a p / n type thermoelectric thin film material; S4: Attach the p / n type thermoelectric thin film material to the flexible substrate and arrange them crosswise in sequence, and then connect them with conductive materials to form electrodes, so that each thermoelectric unit forms a series-parallel structure.

10. The preparation method according to claim 9, characterized in that: The specific process of step S3 includes the following steps: Step 1: Preparation of TiS2 nanosheet dispersion: Take TiS2 powder, n-butyl lithium solution and n-hexane solution and stir them continuously under nitrogen environment until they are fully mixed to synthesize Li x TiS2; filtering the precipitate in the above solution, washing it with n-hexane several times to remove excess n-butyl lithium, then placing the precipitate in deionized water and performing an ultrasonic-assisted stripping process with an ultrasonic power of 200 W for 5 minutes; after the stripping is completed, centrifuging the resulting solution at a speed of 10,000 rpm for several times to obtain a TiS2 nanosheet dispersion; Step 2: Preparation of MoS2 nanosheet dispersion: Take MoS2 powder and n-butyl lithium solution and add them to n-hexane, stir them at room temperature in a nitrogen environment in a glove box until they are fully mixed, place the obtained mixed dispersion in a centrifuge and centrifuge it at a speed of 10,000 rpm for 10 minutes, collect the precipitate after centrifugation, disperse the precipitate in n-hexane and centrifuge it at a speed of 10,000 rpm for 10 minutes and collect the precipitate, repeat this operation 3 times; add the washed precipitate into deionized water, put it into a cell crusher at room temperature and 600 W power for ultrasonic peeling for 60 minutes, put it into a centrifuge again and centrifuge it at 10,000 rpm for 5 minutes to remove the unpeeled MoS2 precipitate, repeat the operation 3 times to obtain a MoS2 nanosheet dispersion; Step 3: Prepare AlCl3-doped TiS2 nanosheets and AlCl3-doped MoS2 nanosheets to assemble thermoelectric thin films: The TiS2 or MoS2 nanosheet dispersion and the AlCl3 solution are uniformly added into a filtration device for vacuum filtration. After completion, the obtained film is vacuum dried at room temperature.

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