Ion thermoelectric device and preparation method thereof

Abstract

The invention discloses an ion thermoelectric device and a preparation method thereof, the ion thermoelectric device comprises a two-dimensional ion thermoelectric device or an integrated three-dimensional ion thermoelectric device, and the two-dimensional ion thermoelectric device comprises an ion thermoelectric gel material, a supporting material and a packaging material which are electrically connected in series. The ion thermoelectric gel materials which are electrically connected in series are arranged on the supporting material, and the two-dimensional ion thermoelectric device can achieve high-voltage output. The integrated three-dimensional ion thermoelectric device comprises an ion thermoelectric conversion module formed by an ion thermoelectric gel material, the ion thermoelectric conversion module comprises a cold end and a hot end which can form temperature difference, and the direction of heat flow in the ion thermoelectric conversion module is perpendicular to the plane where the hot end senses. The integrated three-dimensional ion thermoelectric device can effectively expand the temperature difference between the cold end and the hot end and capture heat flow in the vertical direction, and has high thermoelectric conversion efficiency. The ion thermoelectric device has huge application potential in the fields of waste heat recovery, wearable equipment, health detection and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermoelectric devices, and particularly relates to an ionic thermoelectric device and a preparation method thereof. Background Art

[0002] Thermoelectric generator devices (TEGs) are power supply devices that utilize the Seebeck effect to achieve energy conversion. Under a temperature gradient, the carriers in the device will migrate from the hot end to the cold end, thereby generating a potential difference between the cold end and the hot end. Thermoelectric generator devices mainly rely on thermoelectric materials. However, currently, such materials generally have the defect of low conductivity. In the process of designing the structure of TEGs devices, a large number of thermoelectric legs are usually integrated as two-dimensional planar devices to increase the Seebeck voltage of the device. However, the low bulk conductivity of thermoelectric materials still limits the thermoelectric conversion efficiency of two-dimensional planar devices.

[0003] In addition, TEGs based on highly flexible thermoelectric materials have received attention in the field of wearable electronic devices due to their excellent flexibility and stretchability, and can be attached to the human skin to achieve thermoelectric conversion. Wearable electronic devices can realize the real-time collection of human health data and motion data, etc., providing information support for human health monitoring and motion detection. Wearable electronic devices usually use high-performance micro-batteries for power supply, but the batteries need to be replaced frequently and have a limited lifespan, which cannot meet the real-time acquisition of human data. TEGs can recover the heat generated by the human body and convert it into electrical energy, avoiding the trouble of frequently replacing traditional batteries, improving the convenience of the device, and providing a solution for solving the continuous and stable power supply of wearable electronic devices.

[0004] In addition, currently commonly used thermoelectric generator devices obtain ductility by encapsulating thermoelectric arms in a stretchable elastic matrix. However, the stretching and extension directions of such devices are often limited by the matrix material, and they have poor stability on complex human surfaces and are even less adaptable to the irregular heat source surfaces under the movement state of human skin. At the same time, such devices are usually in-plane structures, and the heat flow direction in the device is perpendicular to the actual temperature gradient direction.

[0005] In the process of implementing the present invention, the inventors found that there are at least the following problems in the prior art: currently, the thermoelectric conversion efficiency of two-dimensional ionic thermoelectric material device structures is low, and they cannot capture the vertical heat flow of the human body. The preparation process of multi-level three-dimensional ionic thermoelectric devices after designing the device structure is cumbersome, costly, the device weight increases significantly, the stability is poor, and it is not conducive to the application of wearable devices. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an ionic thermoelectric device and a preparation method thereof in view of the deficiencies of the above-mentioned prior art. The ionic thermoelectric device includes a two-dimensional ionic thermoelectric device or an integrated three-dimensional ionic thermoelectric device. The two-dimensional ionic thermoelectric device overcomes the low conductivity problem existing in current thermoelectric devices and has a high thermoelectric conversion efficiency. The integrated three-dimensional ionic thermoelectric device has the characteristics of stable thermoelectric performance, reliable service, low contact resistance, simple assembly steps, and light weight and portability.

[0007] The present invention has the following advantages compared with the prior art:

[0008] 1. The two-dimensional ionic thermoelectric device of the present invention uses an electrically connected ionic thermoelectric gel material with a high ionic migration rate and transmission efficiency as the thermoelectric conversion body, overcomes the low conductivity problem existing in current thermoelectric devices, has a high thermoelectric conversion efficiency, and can drive an external load to operate at a temperature difference of 12K, realizing stable thermoelectric conversion under a small temperature difference.

[0009] 2. The present invention creatively provides an integrated three-dimensional ionic thermoelectric device, which is formed into a three-dimensional structure based on the plasticity of the ionic thermoelectric gel material itself, does not rely on other substrates, has voltage stability under strain conditions, is conducive to capturing the heat flow in the out-of-plane direction on the surface of a shaped heat source, and overcomes the defect of mismatched heat flow directions in current thermoelectric devices. In the three-dimensional ionic thermoelectric device, both ends are integrally formed with connecting electrodes, without additional electrodes, avoiding the influence of the connection between the electrodes and the thermoelectric material on the contact resistance and weight of the thermoelectric device, and having the characteristics of stable thermoelectric performance, reliable service, low contact resistance, simple assembly steps, and light weight and portability.

[0010] 3. Preferably, the ionic thermoelectric gel materials in the two-dimensional ionic thermoelectric device and the integrated three-dimensional ionic thermoelectric device are both ionic thermoelectric gel materials obtained by impregnating a bacterial cellulose matrix obtained by freeze-drying and wet spinning into an ion source solution. This ionic thermoelectric gel material uses the rich hydroxyl groups and porous network structure of bacterial cellulose to increase the interaction between hydrogen bonds and ions, and has the characteristics of high liquid content, not easy to leak, large migration difference between anions and cations, high Seebeck coefficient, high ion diffusion flux, and high ionic conductivity.

[0011] The following further describes the technical solutions of the present invention in detail with reference to the drawings and embodiments. Description of the Drawings

[0012] Figure 1 It is the appearance diagram of the ionic thermoelectric gel fiber in Step 1 of Example 1;

[0013] Figure 2 It is the structural schematic diagram of the two-dimensional ionic thermoelectric device in Example 1;

[0014] Figure 3Schematic diagram of the connection relationship between the fiber segment of the two-dimensional ion thermoelectric device and the connecting electrode in Example 1;

[0015] Figure 4 Schematic diagram of the physical demonstration of driving an LCD by the two-dimensional ion thermoelectric device in Example 1;

[0016] Figure 5 Morphology diagram of the helical fiber in Example 2;

[0017] Figure 6 Schematic diagram of the structure of the integrated three-dimensional ion thermoelectric device in Example 2;

[0018] Figure 7 Schematic diagram of the variation of the open-circuit voltage of the integrated three-dimensional ion thermoelectric device with the temperature difference in Example 2;

[0019] Figure 8 Schematic diagram of the physical demonstration of the thermoelectric conversion of the integrated three-dimensional ion thermoelectric device using the out-of-plane temperature difference in Example 2.

[0020] Explanation of reference numerals:

[0021] 1 - Free end of the first helical segment; 2 - End of the first helical segment; 3 - End of the second helical segment;

[0022] 4 - Free end of the second helical segment; 5 - Plane sensed by the hot end. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0024] In the following description, the term "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: the situation of A existing alone, B existing alone, and A and B existing simultaneously. Wherein A and B may be singular or plural.

[0025] In the following description, terms such as "include", "comprise", "have", and "contain" are all open-ended terms, that is, they are intended to include but not limited to.

[0026] Those skilled in the art should understand that in the following description of the embodiments of the present application, the sequence numbers do not mean the order of execution, and some or all of the steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0027] Those skilled in the art should understand that the numerical ranges in the embodiments of the present application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Intermediate values within any stated value or range of values, as well as each smaller range between any other stated value or intermediate value within the stated range, are also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise specified, the technical / scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0029] In some embodiments, a two-dimensional ion thermoelectric device is provided, including an ion thermoelectric gel material, a support material, and a packaging material connected in electrical series. The ion thermoelectric gel material connected in electrical series is disposed on the support material, and the packaging material covers the ion thermoelectric gel material connected in electrical series.

[0030] The two-dimensional ion thermoelectric device uses the ion thermoelectric gel material connected in electrical series as the thermoelectric conversion body, overcomes the existing low-conductance problem, makes full use of the high electrical conductivity characteristic of the ion thermoelectric gel material itself, can drive an external load to operate at a temperature difference of 12K, and realizes stable thermoelectric conversion under a small temperature difference.

[0031] In some embodiments, the series connection mode adopted by the ion thermoelectric gel material connected in electrical series is the planar series connection of the electrode and the ion thermoelectric gel material. The planar series connection includes double parallel series connection and Π-type series connection. The methods of planar series connection include: weaving, printing, coating, assembling, 3D printing, template method, or microfabrication technology. The assembling includes array assembling, layer-by-layer assembling, hot pressing assembling, or self-assembling. In some specific embodiments, the planar series connection form of the ion thermoelectric gel material connected in electrical series is double parallel series connection. The ion thermoelectric gel material connected in electrical series includes: a plurality of ion thermoelectric gel materials and a plurality of connecting electrodes. The plurality of ion thermoelectric gel materials are spaced apart on the support material, and a connecting electrode is connected between two adjacent ion thermoelectric gel materials. The connecting electrode intersects with the corresponding ion thermoelectric gel material, and the intersection points are on different sides. In some specific embodiments, the packaging material only covers the connection points of the ion thermoelectric gel material and the connecting electrode.

[0032] In some embodiments, the connecting electrode is one or more of a metal electrode, a conductive polymer electrode, and a carbon-based material electrode. As an electrical connection component, the connecting electrode can establish connections with multiple ion thermoelectric gel materials to form a multi-leg thermoelectric device, increasing the thermal voltage. The metal electrode can be, for example, one or more of a silver electrode, a gold electrode, a copper electrode, an aluminum electrode, and / or a titanium electrode. The conductive polymer electrode can be, for example, a polypyrrole electrode and / or a polyaniline electrode. The carbon-based material electrode can be, for example, one or more of a graphite electrode, a carbon nanotube electrode, and a graphene electrode.

[0033] In some embodiments, the supporting material can be used to support and install the ion thermoelectric gel materials connected in series electrically, and the encapsulating material can be used to encapsulate the connection part between the ion thermoelectric gel material and the electrode. In some embodiments, the supporting material is a polymer-based supporting material. The polymer-based supporting material can be one or more of a polyimide (PI) supporting material, a polypropylene (PP) supporting material, a polyethylene (PE) supporting material, a polyurethane (PU) supporting material, and a polytetrafluoroethylene (PTFE) supporting material. In some embodiments, the encapsulating material is a polymer-based encapsulating material. The polymer-based encapsulating material can be one or more of a polyimide (PI) encapsulating material, a polypropylene (PP) encapsulating material, a polyethylene (PE) encapsulating material, a polyurethane (PU) encapsulating material, and a polytetrafluoroethylene (PTFE) encapsulating material.

[0034] In some embodiments, the ion thermoelectric gel material is one or more of a polymer-based solid-state ion thermoelectric gel, an ionic liquid-based solid-state ion thermoelectric gel, a hydrogel-based solid-state ion thermoelectric gel, a sulfide / oxide-based solid-state ion thermoelectric gel, and a hybrid ion-electron conductive gel. In some preferred embodiments, the ion thermoelectric gel material is a quasi-solid-state ion thermoelectric gel. The preparation method of the quasi-solid-state ion thermoelectric gel includes impregnating a cellulose matrix obtained by freeze-drying and wet spinning into an ion source solution. The ion source solution is an ion source solution obtained by dissolving an ion source in a solvent. The ion source is one or more of an inorganic salt, an organic salt, a eutectic solvent, and a redox pair. The organic salt includes an ionic liquid and / or a polyionic liquid. In some specific embodiments, the ion source is 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium glycinate, 1-ethyl-3-methylimidazolium cyanamide, 1-ethyl-3-methylimidazolium trifluoromethanesulfinylate, sodium dicyanamide, lithium tetrafluoroborate, choline chloride / glycerol eutectic solvent, choline chloride / ethylene glycol eutectic solvent, redox pair Fe 3+ / Fe 2+ 、redox pair I 3 - / I -, redox pair Fe(CN) 6 3- / 4- and redox pair Ag + / 0 one or more of them, and the solvent is one or more of deionized water, absolute ethanol and glycerol.

[0035] Further preferably, the preparation method of the cellulose matrix includes freeze-drying and wet spinning of bacterial cellulose. Specifically, the bacterial cellulose is one or more of bacterial cellulose of the genus Acetobacter, bacterial cellulose of the genus Agrobacterium and bacterial cellulose of the genus Rhizobium; the ion source solution is a solution containing an ionic liquid, and the ionic liquid is 1-ethyl-3-methylimidazolium chloride (EMIMCl), the solvent is deionized water, and the mass ratio of the ionic liquid to deionized water is (0.4-4):1. The freeze-drying is carried out at -60 to -80 °C for 48 to 60 h, the injection speed of the wet spinning is 5 to 10 mL / h, the inner diameter of the needle used for the wet spinning is 0.16 to 1.7 mm, and the impregnation time is 3 to 30 h.

[0036] In some embodiments, a method for preparing a two-dimensional ion thermoelectric device is provided, including:

[0037] Providing a plurality of ion thermoelectric gel fibers;

[0038] Placing the ion thermoelectric gel fibers at intervals, connecting adjacent two ion thermoelectric gel fibers with electrodes, and fixing the connection points with silver paste to obtain an electrically connected ion thermoelectric gel material;

[0039] Assembling the electrically connected ion thermoelectric gel material, the support material and the encapsulation material to obtain a two-dimensional ion thermoelectric device.

[0040] In other embodiments, an integrated three-dimensional ion thermoelectric device is provided, including an ion thermoelectric conversion module formed by an ion thermoelectric gel material. The ion thermoelectric conversion module includes a cold end and a hot end that can form a temperature difference, and the heat flow direction in the ion thermoelectric conversion module is perpendicular to the plane sensed by the hot end and / or the plane sensed by the cold end.

[0041] The integrated three-dimensional ion thermoelectric device is formed into a three-dimensional structure based on the plasticity of the ion thermoelectric gel material itself, does not depend on other substrates, has voltage stability under strain conditions, is conducive to capturing the heat flow on the surface of a special-shaped heat source and in the out-of-plane direction, overcomes the defect of the mismatch of the heat flow direction of the current thermoelectric device, and the two ends of the three-dimensional ion thermoelectric device are integrally formed with the connecting electrodes, without additional electrodes, avoiding the influence of the connection between the electrodes and the thermoelectric material on the contact resistance and weight of the thermoelectric device, and having the characteristics of stable thermoelectric performance, reliable service, low contact resistance, simple assembly steps, and light weight and portability.

[0042] The thermoelectric conversion module is the most basic component of a thermoelectric device, having opposite ends for sensing temperature differences. One end is the cold end, and the other end is the hot end. When a certain temperature difference is maintained between the cold end and the hot end, the thermoelectric conversion module acts as a generator and transfers electricity to external devices. The direction of heat flow within the thermoelectric device is the transmission direction of heat flow between the hot end and the cold end. The plane sensed by the hot end is the temperature plane in contact with the hot end, such as the human skin when used as a wearable power supply device. At this time, the cold end contacts the air, and a temperature gradient is formed between the air and the human skin. The direction of heat flow is perpendicular to the plane where the human skin is located and is consistent with the direction of the temperature gradient.

[0043] In some embodiments, the ionic thermoelectric conversion module is formed by shaping an ionic thermoelectric gel material into a spiral shape and then partially straightening and bending it.

[0044] Preferably, both the cold end and the hot end of the three-dimensional ionic thermoelectric device are spiral structures, which can achieve sufficient thermal contact with the corresponding heat source or cold source, improving the effective temperature difference of the thermoelectric device. The ionic thermoelectric conversion module in this embodiment is formed by shaping an ionic thermoelectric gel material, and it forms the hot end, the cold end, and the connecting electrodes by itself. The preparation process is simple and the cost is low.

[0045] In some embodiments, the ionic thermoelectric gel material is one or more of a polymer-based solid-state ionic thermoelectric gel, an ionic liquid-based solid-state ionic thermoelectric gel, a hydrogel-based solid-state ionic thermoelectric gel, a sulfide / oxide-based solid-state ionic thermoelectric gel, and a mixed ionic-electronic conductive gel. In some preferred embodiments, the ionic thermoelectric gel material is a quasi-solid-state ionic thermoelectric gel; the preparation method of the quasi-solid-state ionic thermoelectric gel includes impregnating a cellulose matrix obtained by freeze-drying and wet spinning into an ion source solution; the ion source solution is an ion source solution obtained by dissolving an ion source in a solvent, and the ion source is one or more of inorganic salts, organic salts, eutectic solvents, and redox couples. The organic salts include ionic liquids and / or polyionic liquids; in some specific embodiments, the ion source is 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium glycinate, 1-ethyl-3-methylimidazolium cyanamide, 1-ethyl-3-methylimidazolium trifluoromethanesulfinate, sodium dicyanamide, lithium tetrafluoroborate, choline chloride / glycerol eutectic solvent, choline chloride / ethylene glycol eutectic solvent, redox couple Fe 3+ / Fe 2+ 、redox couple I 3 - / I - 、redox couple Fe(CN) 6 3- / 4- and redox couple Ag + / 0One or more of them, and the solvent is one or more of deionized water, absolute ethanol, and glycerol. Currently, the method for preparing quasi-solid-state ion thermoelectric gels is usually to directly mix the gel matrix and the ion source and then form them to obtain quasi-solid-state ion thermoelectric gels. The morphology of the ion thermoelectric gels is a thin film or fiber. The forming includes chemical deposition or extrusion. For example, the extrusion can be electrospinning extrusion, melt extrusion, or injection molding. In some embodiments, an ion thermoelectric gel material with a fibrous morphology is obtained by impregnating a cellulose matrix obtained by freeze-drying and wet spinning into an ion source solution. During the impregnation process, the hydration interaction between ions and water molecules and the electrostatic interaction between ions and cellulose-based fibers cooperate synergistically, and the diffusion migration difference between anions and cations increases significantly, overcoming the defect of low conductivity of the ion thermoelectric gels prepared by conventional methods. The ion thermoelectric gel material obtained by the method of freeze-drying and wet spinning followed by impregnation has a significantly improved Seebeck coefficient and thermoelectric conversion efficiency.

[0046] Further preferably, the method for preparing the cellulose matrix includes freeze-drying and wet spinning of bacterial cellulose. Specifically, the bacterial cellulose is one or more of bacterial cellulose of the genus Acetobacter, bacterial cellulose of the genus Agrobacterium, and bacterial cellulose of the genus Rhizobium; the ion source solution is a solution containing an ionic liquid, and the ionic liquid is 1-ethyl-3-methylimidazolium chloride (EMIMCl), the solvent is deionized water, and the mass ratio of the ionic liquid to deionized water is (0.4 - 4):1. The freeze-drying is carried out at -60 to -80 °C for 48 to 60 h, the injection speed of the wet spinning is 5 to 10 mL / h, the inner diameter of the needle used for wet spinning is 0.16 to 1.7 mm, and the impregnation time is 3 to 30 h. The cellulose matrix is a cellulose matrix obtained by homogenizing cellulose and then freeze-drying. It has a loose texture and a porous structure inside, and the ion source is fully compatible with the cellulose matrix during the subsequent impregnation process, and the element distribution is uniform.

[0047] In some embodiments, a method for preparing an integrated three-dimensional ion thermoelectric device is provided, including:

[0048] Processing the ion thermoelectric gel fiber into a spiral shape;

[0049] Pulling open the middle section of the spiral ion thermoelectric gel fiber to obtain a shaped fiber, and the shaped fiber sequentially includes a free end of the first spiral section, an end of the first spiral section, an end of the second spiral section, and a free end of the second spiral section;

[0050] Bending the shaped fiber so that the free end of the first spiral section and the end of the second spiral section are the ends in contact with the same heat source to obtain an integrated three-dimensional ion thermoelectric device.

[0051] The processing of the ion thermoelectric gel fiber into a spiral shape is carried out by a winding process. The winding process specifically involves manually winding a rod with a preset diameter, and the preset diameter is 2.2 - 10 mm; the length of the spiral ion thermoelectric gel fiber is 6 - 10 cm, and the diameter of the spiral ring is 2.2 - 10 mm; the height difference between the cold end and the hot end is 1 - 3 cm, and the length of the spiral section corresponding to the middle section before being pulled apart is 1 / 3 - 1 / 2 of the length of the spiral ion thermoelectric gel fiber.

[0052] A series of experiments were conducted before the application of this invention. Now, some test results are listed to further describe the invention in detail. The following will be described in detail in combination with the embodiments.

[0053] Embodiment 1

[0054] This embodiment provides a preparation method for a two-dimensional ion thermoelectric device, including:

[0055] Step 1: Provide ion thermoelectric gel fibers, specifically including:

[0056] Step 101: Place bacterial cellulose (BC) in a homogenizer and crush it at a rate of 72000 rpm for 10 minutes to obtain a bacterial cellulose suspension; the bacterial cellulose is acetic acid bacillus cellulose hydrogel BC, purchased from Guilin Qihong Technology, in the form of a film, the size of A4 paper, and about 3 mm thick;

[0057] Step 102: Place the bacterial cellulose suspension in a -20 °C low-temperature refrigerator for pre-cooling to obtain a pre-cooled sample. Freeze-dry the pre-cooled sample at -80 °C for 48 h to obtain a freeze-dried sample. Place the freeze-dried sample in a LiCl / DMAc mixed solvent and stir it at a speed of 1000 r / min at room temperature for 14 h to obtain a spinning dope; in the spinning dope, the mass percentage content of LiCl is 8 wt%, and the mass percentage content of DMAc is 88 wt%;

[0058] Step 103: Place the spinning dope in a syringe with a capacity of 10 mL and a needle inner diameter of 0.49 mm, and extrude it into a deionized water coagulation bath with a micro-injection pump at an injection speed of 5 mL / h, and let it stand for 20 min for solvent exchange, and dry it at room temperature to obtain bacterial cellulose fibers (BC fiber);

[0059] Step 104: At room temperature, immerse the bacterial cellulose fibers obtained in step 103 in an ion source solution with a mass percentage content of 45% for impregnation to obtain ion thermoelectric gel fibers (BC / H 2(O-EMIMCI); wherein, the ion source solution is a solution obtained by stirring and mixing ionic liquid 1-ethyl-3-methylimidazolium chloride (EMIMCl) and deionized water at room temperature, the impregnation time is 6 h, and the impregnation is static impregnation; the morphology of the ion thermoelectric gel fiber in Example 1 is as Figure 1 shown;

[0060] Step 2: Cut the ion thermoelectric gel fiber into fiber segments with a length of 2.5 - 3 cm. Using a polyimide film as a support, place the fiber segments parallel and at intervals. Lay high-purity silver wires between adjacent fiber segments, with multiple high-purity silver wires spaced apart, and fix the overlapping points with silver paste to achieve the series connection of the fiber segments. Cover the fixed points with insulating tape to obtain a two-dimensional ion thermoelectric device; wherein the number of fiber segments is 16, and the insulating tape is polytetrafluoroethylene insulating tape; the structural schematic diagram of the two-dimensional ion thermoelectric device is as Figure 2 shown, Figure 3 is the structural schematic diagram of the unencapsulated two-dimensional ion thermoelectric device, where transparent tape is used to replace the insulating tape for the purpose of showing the connection relationship between the fiber segments and the silver electrodes; the polyimide film is KAPTON polyimide film, with a thickness of 0.05 × width of 500 mm, purchased from Hudian Hardware; the polytetrafluoroethylene insulating tape is a Teflon high-temperature resistant and heat-insulating insulating tape, with a width of 13 mm × thickness of 0.18 mm, purchased from Maikaisi Mechanical and Electrical Hardware.

[0061] Example 2

[0062] This example provides an integrated three-dimensional ion thermoelectric device, including an ion thermoelectric conversion module formed by an ion thermoelectric gel material. The ion thermoelectric conversion module includes a cold end and a hot end that can form a temperature difference, and the heat flow direction in the ion thermoelectric conversion module is perpendicular to the plane sensed by the hot end and / or the plane sensed by the cold end.

[0063] This example also provides a preparation method for the above integrated three-dimensional ion thermoelectric device, including:

[0064] Step 1: Provide ion thermoelectric gel fibers, which are the same as the ion thermoelectric gel fibers in Example 1;

[0065] Step 2: Manually wind the ion thermoelectric gel fiber onto a rod to process it into a spiral fiber with a pitch of about 2.3 mm, and cut the spiral fiber to obtain a spiral fiber segment with a length of 8 cm. The diameter of the rod is 4 mm, and the diameter of the spiral ring is 4 mm;

[0066] Step 3: Select a spiral segment about 3 cm in the middle section, stretch it to reduce the curvature to obtain a shaped fiber, where the shaped fiber sequentially includes a free end 1 of the first spiral segment, a terminal 2 of the first spiral segment, a terminal 3 of the second spiral segment, and a free end 4 of the second spiral segment; the structure is as Figure 6 shown;

[0067] Step 4: Bend the shaped fiber, with the free end 1 of the first helical segment and the end 3 of the second helical segment being the end in contact with the same heat source, to obtain an integrated three-dimensional ionic thermoelectric device; the end in contact with the same heat source is the hot end or the cold end.

[0068] Performance evaluation

[0069] The thermoelectric properties of the ionic thermoelectric gel fiber in Step 1 of Example 1 are shown in Table 1. The Seebeck coefficient was measured by a nanovoltmeter (Keithley 2182A), and the open-circuit voltage and the temperature gradient between two silver electrodes were collected by two T-type thermocouples connected to a Keithley 7710 multimeter respectively. The conductivity was obtained by testing with an electrochemical workstation through potentiostatic control. As can be seen from Table 1, at a test temperature of room temperature and an environmental humidity of 80RH%, the Seebeck coefficient of the ionic thermoelectric gel fiber in Step 1 of Example 1 is 27.76 mV·K -1 , and the conductivity is 198.75 mS·cm -1 , showing excellent thermoelectric properties.

[0070] Table 1 Thermoelectric properties of the ionic thermoelectric gel fiber in Step 1 of Example 1

[0071] <![CDATA[Seebeck coefficient mV·K -1 > <![CDATA[Conductivity mS·cm -1 > Ionic thermoelectric gel fiber 27.76 198.75

[0072] Place the two-dimensional ionic thermoelectric device of Example 1 on a Peltier, so that the ionic thermoelectric device is in a stable temperature difference state. Connect a small low-power LCD screen with a working voltage of 3V and a working current of 2 μA in series at both ends of the device. The connection structure diagram is as Figure 4 shown. According to Figure 4 it can be seen that when the temperature difference at both ends of the two-dimensional ionic thermoelectric device is controlled to be 12K, an image is displayed on the LCD screen, indicating that the two-dimensional ionic thermoelectric device of the present invention successfully drives the LCD screen device to operate.

[0073] The helical fiber morphology of Example 2 is as Figure 5 shown, indicating that the ionic thermoelectric fiber of this example has processability.

[0074] Taking the human skin as the hot-end sensing plane 5, the free end 1 of the first helical segment and the end 3 of the second helical segment of the integrated three-dimensional ionic thermoelectric device of Example 2 are the hot ends. Use double-sided adhesive tape to fix the hot ends on the human tissue. The part from the free end 1 of the first helical segment to the end 2 of the first helical segment (including the end 2 of the first helical segment) and the part from the end 3 of the second helical segment to the free end 4 of the second helical segment (including the free end 4 of the second helical segment) are far away from the human tissue under the support of the helical fiber body and serve as the cold ends to sense the air temperature around the human body. The part between the end 2 of the first helical segment and the end 3 of the second helical segment serves as the connection electrode. The schematic diagram is as Figure 6As shown. Based on Figure 6 It can be seen that the integrated three-dimensional ion thermoelectric device of this embodiment can be applied to the human body as a wearable device.

[0075] Place the free end 1 of the first helical section and the end 3 of the second helical section of the integrated three-dimensional ion thermoelectric device of Embodiment 2 on the Peltier, using the Peltier as the sensing plane of the hot end, control the temperature of the Peltier, so that a stable temperature difference is generated between the cold end and the hot end of the integrated three-dimensional ion thermoelectric device, and measure the open-circuit voltage at different temperature differences. The results are as Figure 7 As shown. Based on Figure 7 It can be seen that the integrated three-dimensional ion thermoelectric device of this embodiment has good thermal response behavior, and the voltage can be stably output at different temperature differences. Moreover, as the temperature difference increases, the voltage shows an approximately linear increasing trend.

[0076] Fix the end 2 of the first helical section and the free end 4 of the second helical section of the integrated three-dimensional ion thermoelectric device of Embodiment 2 on the desktop through double-sided adhesive tape as the cold end, and the rest is higher than the desktop. The desktop temperature is different from the air temperature, and a temperature difference is generated between the cold end and the hot end. The test schematic diagram is as Figure 8 As shown. Based on Figure 8 It can be seen that the temperature difference between the desktop and the air measured by the thermocouple is 6.46 K. Under this working condition, the integrated three-dimensional ion thermoelectric device generates a thermal voltage of about 338 mV, indicating that the integrated three-dimensional ion thermoelectric device of this embodiment can make full use of the temperature gradient between the desktop as the cold source and the external applied heat source to expand the temperature difference between the cold and hot ends and improve the effective temperature difference of the thermoelectric device.

Claims

1. A two-dimensional ionic thermoelectric device, characterized in that: The invention comprises an ionic thermoelectric gel material electrically connected in series, a supporting material and a packaging material. The ionic thermoelectric gel material electrically connected in series is arranged on the supporting material, and the packaging material covers the ionic thermoelectric gel material electrically connected in series.

2. The two-dimensional ionic thermoelectric device according to claim 1, characterized in that: The electrically series-connected ionic thermoelectric gel material comprises a plurality of ionic thermoelectric gel materials, the plurality of ionic thermoelectric gel materials are arranged at intervals on a support material, and a connecting electrode is connected between two adjacent ionic thermoelectric gel materials.

3. The two-dimensional ionic thermoelectric device according to claim 2, characterized in that: The connecting electrode is one or more of a metal electrode, a conductive polymer electrode and a carbon-based material electrode; and / or the ionic thermoelectric gel material is one or more of a polymer-based solid-state ionic thermoelectric gel, an ionic liquid-based solid-state ionic thermoelectric gel, a hydrogel-based solid-state ionic thermoelectric gel, a sulfide / oxide-based solid-state ionic thermoelectric gel and a hybrid ionic electronic conductive gel; and / or the supporting material is a polymer-based supporting material; and / or the packaging material is a polymer-based packaging material.

4. The two-dimensional ionic thermoelectric device according to claim 2, characterized in that: The preparation method of the ionic thermoelectric gel material comprises: immersing a cellulose matrix obtained by freeze-drying and wet spinning in an ion source solution; and / or, the preparation method of the cellulose matrix comprises freeze-drying and wet spinning bacterial cellulose, the ion source solution is an ion source solution composed of ionic liquid and deionized water; and / or, the mass ratio of ionic liquid to deionized water is (0.4-4):1; and / or, the freeze-drying temperature is -60--80°C, and the freeze-drying time is 48-60h; and / or, the feed speed of wet spinning is 5-10mL / h, and the inner diameter of the needle used for wet spinning is 0.16-1.7mm; and / or, the immersion time is 3-30h.

5. A method for preparing the two-dimensional ionic thermoelectric device as claimed in claim 1, characterized in that: include: providing a plurality of ionic thermoelectric gel fibers; The ionic thermoelectric gel fibers are placed at intervals, two adjacent ionic thermoelectric gel fibers are connected by connecting electrodes, a plurality of the connecting electrodes are spaced apart, and the connecting points are fixed by silver paste to obtain an ionic thermoelectric gel material connected in series; The ionic thermoelectric gel material, supporting material and packaging material connected in series are assembled to obtain a two-dimensional ionic thermoelectric device.

6. An integrated three-dimensional ionic thermoelectric device, characterized in that: An ionic thermoelectric conversion module formed of an ionic thermoelectric gel material includes a cold end and a hot end that can form a temperature difference, and a heat flow direction in the ionic thermoelectric conversion module is perpendicular to a sensing plane of the hot end and / or a sensing plane of the cold end.

7. The integrated three-dimensional ionic thermoelectric device according to claim 6, characterized in that: The ion thermoelectric conversion module is formed by molding the ion thermoelectric gel material into a spiral shape and then partially straightening and bending it.

8. The integrated three-dimensional ionic thermoelectric device according to claim 6, characterized in that: The preparation method of the ionic thermoelectric gel material comprises: immersing a cellulose matrix obtained by freeze-drying and wet spinning in an ion source solution; and / or, the preparation method of the cellulose matrix comprises freeze-drying and wet spinning bacterial cellulose, the ion source solution is an ion source solution composed of ionic liquid and deionized water; and / or, the mass ratio of ionic liquid to deionized water is (0.4-4):1; and / or, the freeze-drying temperature is -60--80°C, and the freeze-drying time is 48-60h; and / or, the feed speed of wet spinning is 5-10mL / h, and the inner diameter of the needle used for wet spinning is 0.16-1.7mm; and / or, the immersion time is 3-30h.

9. A method for preparing the integrated three-dimensional ionic thermoelectric device according to claim 6, characterized in that: include: Processing the ionic thermoelectric gel fiber into a spiral shape; The middle section of the spiral ion thermoelectric gel fiber is straightened to obtain a shaped fiber, wherein the shaped fiber sequentially includes a first spiral section free end, a first spiral section end, a second spiral section end, and a second spiral section free end; The plasticized fiber is bent, and the free end of the first spiral segment and the end of the second spiral segment are used as the ends in contact with the same heat source to obtain an integrated three-dimensional ionic thermoelectric device.

10. The method according to claim 9, characterized in that The pitch of the helical ion thermoelectric gel fiber is 2 to 3 mm.

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