An ion thermogel device, its preparation method and application

Abstract

This invention belongs to the field of thermoelectric materials technology, specifically disclosing an ion thermoelectric gel device, its preparation method, and its application. The ion thermoelectric gel device includes at least one device; the device includes a first electrode, an ion thermoelectric gel unit, and a second electrode arranged in series; the first electrode and / or the second electrode includes a substrate layer and a conductive layer stacked together; the substrate layer is made of an elastic polymer material; the conductive layer is made of conductive particles and conductive nanowires; the conductive particles coat the surface of the conductive nanowires, and the materials of the conductive particles and the conductive nanowires are each independently selected from at least one of gold, silver, platinum, and copper. This device exhibits excellent ion thermoelectric potential and high normalized power density, effectively solving the long-standing core bottleneck of insufficient output power in this field.

Description

Technical Field

[0001] This invention belongs to the field of thermoelectric materials technology, and specifically relates to an ion thermoelectric gel device, its preparation method and application. Background Technology

[0002] To meet the self-powered needs of wearable electronics and IoT sensors for efficiently harvesting low-grade heat from the environment and human body, ionothermal gel devices are considered a promising solution due to their excellent ionothermal potential and biocompatibility. However, their practical application is still hampered by the lack of fully flexible and stretchable devices, making it difficult to form stable contact with dynamically bending human skin surfaces, leading to a decline in thermoelectric performance. A key bottleneck exists at the structural level: although the gel itself possesses excellent flexibility, the stretchability of traditional electrode materials (such as rigid metals, brittle carbon composites, and conductive polymers) is severely insufficient, unable to adapt to continuous deformation, limiting the mechanical durability and energy output stability of the device in real-world wearable environments. Although some studies have developed several stretchable electrode fabrication processes by combining conductive nanomaterials (such as carbon nanotubes, metal nanowires, and conductive polymers) with elastic substrates, the overall thermoelectric conversion capability of the device is fundamentally limited by the gel system itself. Specifically, the scarcity of widely used redox couples restricts further performance improvement and application expansion, necessitating the development of novel redox material systems with efficient thermoelectric response and stability. Summary of the Invention

[0003] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide an ion thermoelectric gel device.

[0004] The second objective of this invention is to provide a method for preparing an ion thermoelectric gel device.

[0005] A third objective of this invention is to provide a product containing the above-mentioned ion thermoelectric gel device.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A first aspect of the present invention provides an ion thermoelectric gel device, comprising at least one device; said device includes a first electrode, an ion thermoelectric gel unit, and a second electrode arranged in series. The first electrode and / or the second electrode include a substrate layer and a conductive layer stacked together; the substrate layer is made of an elastic polymer material; The conductive layer is made of conductive particles and conductive nanowires; the conductive particles coat the surface of the conductive nanowires, and the materials of the conductive particles and the conductive nanowires are each independently selected from at least one of gold, silver, platinum, and copper.

[0007] In some embodiments of the present invention, a core-shell structure is formed between the conductive particles and the conductive nanowires, with the conductive particles forming the shell and the conductive nanowires forming the core.

[0008] In some embodiments of the present invention, the at least one device is connected in series.

[0009] In some embodiments of the present invention, the ion thermoelectric gel unit includes an n-type ion thermoelectric gel, a p-type ion thermoelectric gel, or an np-type ion thermoelectric gel. The np-type ion thermoelectric gel includes an n-type ion thermoelectric gel and a p-type ion thermoelectric gel arranged in series.

[0010] In some embodiments of the present invention, the p-type ion thermoelectric gel comprises a first gel matrix, an inorganic two-dimensional nanomaterial, a first metal salt, and water; the inorganic two-dimensional nanomaterial, the first metal salt, and water are all distributed in the first gel matrix.

[0011] In some embodiments of the present invention, the n-type ion thermoelectric gel comprises a second gel matrix, a second metal salt, a redox couple, and water; the redox couple, the second metal salt, and water are all distributed in the second gel matrix.

[0012] In this invention, the first gel matrix and the second gel matrix can be the same or different.

[0013] In some embodiments of the present invention, the first metal salt and the second metal salt are not the same.

[0014] In some embodiments of the present invention, the first metal salt is selected from at least one of inorganic metal salts and organic metal salts.

[0015] In some embodiments of the present invention, the first metal salt is selected from Na. 42 [Mo VI 72 Mo V 60 O 372 (CH3COO) 30 (H2O) 72 ]、K 42 [Mo VI 72 Mo V 60 O 372 (CH3COO) 30 (H2O) 72 ]、 (NH4) 80 [Mo V 180 Mo VI 80(OH) 60 O 700 ] At least one of 240H2O. In the first metal salt of the present invention, Mo... VI This refers to a molybdenum atom with a valence state of +6; Mo V It refers to a molybdenum atom with a valence of +5.

[0016] In some embodiments of the present invention, the second metal salt is selected from at least one of inorganic metal salts and organic metal salts.

[0017] In some embodiments of the present invention, the second metal salt is selected from at least one of sodium sulfate, sodium carbonate, potassium carbonate, potassium chloride, sodium nitrate, potassium sulfate, sodium chloride, and potassium nitrate.

[0018] In this invention, a redox couple refers to a pair consisting of the same element in a higher oxidation state (oxidized form) and a lower oxidation state (reduced form), usually represented as oxidized form / reduced form (e.g., Fe). 3+ / Fe 2+ I - / I3 - This pair of substances interconverts through the gain and loss of electrons, constituting a half-reaction.

[0019] In some embodiments of the present invention, the material of the redox couple is selected from at least one of K3Fe(CN)6 / K4Fe(CN)6, Na3Fe(CN)6 / Na4Fe(CN)6, Na2SO4 / Na2SO3, K2SO4 / K2SO3, KI / I3, and NaI / I3.

[0020] In some embodiments of the present invention, the material of the redox couple is selected from at least one of KI / I3 and NaI / I3.

[0021] In some embodiments of the present invention, the material of the redox couple is selected from KI / I3; the molar ratio of KI to I3 in the KI / I3 is 1:(0.3-1).

[0022] In some embodiments of the present invention, the material of the redox couple is selected from NaI / I3; the molar ratio of NaI to I3 in NaI / I3 is 1:(0.3-1).

[0023] In some embodiments of the present invention, the inorganic two-dimensional nanomaterial is an MXene material. In some embodiments of the present invention, the MXene material includes at least one of titanium-based MXene, vanadium-based MXene, and molybdenum-based MXene.

[0024] In some embodiments of the present invention, the titanium-based MXene comprises Ti3C2T x T x This refers to -OH, -F, or -O, etc.

[0025] In some embodiments of the present invention, the material of the first gel matrix includes at least one selected from gelatin, polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, polyethylene glycol, and polyacrylamide.

[0026] In some embodiments of the present invention, the material of the second gel matrix includes at least one selected from gelatin, polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, polyethylene glycol, and polyacrylamide.

[0027] In some embodiments of the present invention, the concentration of the first metal salt in the p-type ion thermogel is less than the concentration of the second metal salt in the n-type ion thermogel.

[0028] In some embodiments of the present invention, the molar concentration of the first metal salt in the p-type ion thermogel is 0.0002~0.0006 mol / L; in some embodiments of the present invention, the molar concentration of the first metal salt in the p-type ion thermogel is 0.0003~0.0005 mol / L; in some embodiments of the present invention, the molar concentration of the first metal salt in the p-type ion thermogel is 0.000421 mol / L.

[0029] In some embodiments of the present invention, the molar concentration of the second metal salt in the n-type ion thermogel is (0.1~1) mol / L; in some embodiments of the present invention, the molar concentration of the second metal salt in the n-type ion thermogel is (0.1~0.5) mol / L; in some embodiments of the present invention, the molar concentration of the second metal salt in the n-type ion thermogel is (0.2~0.4) mol / L.

[0030] In some embodiments of the present invention, the mass-to-volume ratio of water in the first gel matrix and the p-type ionic thermoelectric gel is 1 g:(2-20) mL; in some embodiments of the present invention, the mass-to-volume ratio of water in the first gel matrix and the p-type ionic thermoelectric gel is 1 g:(2-10) mL.

[0031] In some embodiments of the present invention, the inorganic two-dimensional nanomaterial has a mass concentration of 1~2 g / L in the p-type ion thermoelectric gel.

[0032] In some embodiments of the present invention, the molar concentration of the redox couple in the n-type ionic thermoelectric gel is 3-8 mmol / L; in some embodiments of the present invention, the molar concentration of the redox couple in the n-type ionic thermoelectric gel is 4-6 mmol / L; in some embodiments of the present invention, the molar concentration of the redox couple in the n-type ionic thermoelectric gel is 5 mmol / L.

[0033] In some embodiments of the present invention, the mass-to-volume ratio of the second gel matrix to the water in the n-type ion thermoelectric gel is 1 g:(1-5) mL.

[0034] In some embodiments of the present invention, the elastic polymer material is selected from at least one of polyurethane, polydopamine-modified polydimethylsiloxane, gelatin, and polyvinyl alcohol hydrogel.

[0035] In some embodiments of the present invention, the first electrode or the second electrode is conductive graphite paper; the conductive graphite paper includes graphite paper and a conductive material layer selected from at least one of gold, silver, platinum and copper disposed on the surface of the graphite paper.

[0036] In some embodiments of the present invention, the conductive layer is composed of conductive particles and conductive nanowires; the conductive particles coat the surface of the conductive nanowires; and the substrate layer is made of an elastic polymer material. The present invention uses a novel electrode with a core-shell structured conductive layer and a flexible substrate layer to replace the traditional rigid electrode, achieving a good balance between conductivity, tensile strength, and stability. The flexible device constructed based on this exhibits excellent mechanical durability; after undergoing 50% tensile deformation, the thermoelectric potential of the material decreases from 31.2 mV·K. -1 A slight decrease of 30.3 mV·K -1 The temperature drop was only about 2.88%, demonstrating excellent mechanical deformation stability and thermoelectric robustness. This characteristic of maintaining almost constant thermoelectric parameters under significant strain indicates that its structure possesses excellent flexibility and thermoelectric compatibility, showing outstanding application potential in stretchable thermoelectric devices and flexible self-powered systems. Ultimately, the device integrating multiple np-type ion thermoelectric gels achieved an open-circuit voltage of nearly 4 V and an output power of nearly 100 microwatts at a temperature difference of 10 K. Its excellent overall performance lays a solid technical foundation for developing a new generation of self-powered wearable devices adapted to complex deformation environments.

[0037] In some embodiments of the present invention, the material of the conductive layer is at least one of gold-coated copper nanowires, platinum-coated silver nanowires, and silver-coated copper nanowires.

[0038] In some embodiments of the present invention, the ion thermogel device can operate stably in a temperature range of 10-80 °C; in some embodiments of the present invention, the ion thermogel device can operate stably in a temperature range of 15-60 °C; in some embodiments of the present invention, the ion thermogel device can operate stably in a temperature range of 20-40 °C.

[0039] In some embodiments of the present invention, when the ion thermoelectric gel device is in operation, the temperature difference between the p-type ion thermoelectric gel and the n-type ion thermoelectric gel is 1~20K.

[0040] In some embodiments of the present invention, the p-type ion thermoelectric gel is prepared by mixing and reacting raw materials including materials for preparing a first gel matrix, a first metal salt, inorganic two-dimensional nanomaterials, and water, followed by heating and reaction; the materials for preparing the first gel matrix include polymeric monomers, initiators, and crosslinking agents.

[0041] In some embodiments of the present invention, the polymeric monomers in the material used to prepare the first gel matrix include at least one of acrylic acid, methacrylic acid, acrylamide, vinyl alcohol, and ethylene glycol.

[0042] In some embodiments of the present invention, the initiator in the material used to prepare the first gel matrix includes at least one of ammonium persulfate, potassium persulfate, 2-hydroxy-2-methylphenylacetone, and azobisisobutyronitrile.

[0043] In some embodiments of the present invention, the crosslinking agent in the material used to prepare the first gel matrix is ​​selected from at least one of N,N'-methylenebisacrylamide, polyethylene glycol diacrylate, dicumyl peroxide, and benzoyl peroxide.

[0044] In some embodiments of the present invention, the heating reaction temperature is 40~70°C when preparing p-type ion thermoelectric gel.

[0045] In some embodiments of the present invention, the n-type ionic thermoelectric gel is prepared by mixing and reacting raw materials including materials for preparing a second gel matrix, a second metal salt, redox pairs, and water, followed by heating and reaction; the materials for preparing the second gel matrix include polymeric monomers, initiators, and photoinitiators.

[0046] In some embodiments of the present invention, the polymeric monomers in the material used to prepare the second gel matrix include at least one of acrylic acid, methacrylic acid, acrylamide, vinyl alcohol, and ethylene glycol.

[0047] In some embodiments of the present invention, the initiator in the material used to prepare the second gel matrix includes at least one of ammonium persulfate, potassium persulfate, 2-hydroxy-2-methylphenylacetone, and azobisisobutyronitrile.

[0048] In some embodiments of the present invention, the photoinitiator in the material used to prepare the second gel matrix is ​​selected from 2-hydroxy-2-methylphenylacetone.

[0049] In some embodiments of the present invention, the mixing reaction is carried out under ultraviolet light initiation when preparing the n-type ion thermoelectric gel.

[0050] In some embodiments of the present invention, the heating reaction temperature is 40~70°C when preparing the n-type ion thermoelectric gel.

[0051] The second aspect of the present invention provides a method for preparing the ion thermoelectric gel device described in the first aspect of the present invention, comprising the following steps: The first electrode, the ion thermoelectric gel unit, and the second electrode are connected in series to form the electrode.

[0052] In some embodiments of the present invention, the fabrication method further includes the step of connecting the at least one device in series. In some embodiments of the present invention, the fabrication method further includes the step of connecting the at least one device in series using a first electrode or a second electrode.

[0053] In some embodiments of the present invention, the at least one np-type ion thermoelectric gel is connected in series via copper conductive adhesive.

[0054] A third aspect of the present invention provides a product comprising the ion thermoelectric gel device described in the first aspect of the present invention; the product comprising a thermoelectric generator, a sensor, a battery, or a wearable device.

[0055] The beneficial effects of this invention are as follows: Both the first and second gel matrices in the ion thermoelectric gel device of this invention are flexible, possessing excellent toughness and capable of withstanding stretching, bending, and torsion deformations without breaking, thus constructing an ion thermoelectric gel system with excellent deformation adaptability. This gel material maintains good thermoelectric conversion performance while exhibiting outstanding tensile flexibility and mechanical stability, enabling it to adapt to complex curved surfaces and dynamic deformation requirements. It is suitable for developing next-generation flexible ion thermoelectric conversion devices and wearable thermoelectric power generation devices.

[0056] This invention innovatively introduces a class of metal-oxygen clusters with high charge density and multi-electron transfer properties as the first metal salt, and combines this with the interface modulation and mechanical enhancement effects of inorganic two-dimensional nanomaterials to construct a high-performance ternary composite gel. This material exhibits a high performance of up to 30 mV·K. -1The above ion thermoelectric potential is as high as 3.5 mW·m -2 ·K -2 The normalized power density mentioned above is more than 80% higher than that of traditional systems, effectively solving the core bottleneck of insufficient output power that has long existed in this field. Attached Figure Description

[0057] Figure 1 Na {Mo} in the embodiments of the present invention 132 XRD test image of}.

[0058] Figure 2 This is a flowchart illustrating the preparation process of the flexible, stretchable p-type ionic thermogel in Example 1.

[0059] Figure 3 The image shows the plasticized physical specimen of the flexible stretchable p-type thermoelectric gel in Example 1 during stretching, bending, and torsion tests.

[0060] Figure 4 The temperature difference-voltage relationship curves of the flexible stretchable p-type thermoelectric gels in Examples 1 to 3 are test graphs.

[0061] Figure 5 The normalized power density test graphs are for the flexible and stretchable p-type ion thermoelectric gel devices of Examples 1-2.

[0062] Figure 6 The temperature difference-voltage relationship curve is a test graph of the n-type ion thermoelectric gel unit in Example 4.

[0063] Figure 7 The graph shows the power voltage-current density and power density-current density curves of the n-type ion thermoelectric gel unit in Example 4 under no tensile strain.

[0064] Figure 8 The graph shows the power voltage-current density and power density-current density curves of the n-type ion thermoelectric gel unit in Example 4 under 25% tensile strain.

[0065] Figure 9 The graph shows the power voltage-current density and power density-current density curves of the n-type ion thermoelectric gel unit in Example 4 under 50% tensile strain.

[0066] Figure 10 The voltage-time variation curve is shown in Example 6 when the wearable device collects human thermal energy.

[0067] Figure 11 This is a graph showing the voltage and temperature difference of the thermoelectric power generation module in Example 7 as a function of time.

[0068] Figure 12This is a test graph showing the voltage-current density and power-current density curves of the thermoelectric power generation module in Example 7. Detailed Implementation

[0069] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0070] The raw material information used in the following examples and comparative examples is as follows: Acrylic acid (AA, >99%) and N,N,N',N'-tetraethylethylenediamine (BIS) were purchased from Macklin, Energy Chemicals. Potassium persulfate (KPS) was purchased from Aladdin Co. Ti3C2T X Mxene nanosheets were purchased from Foshan Xinxi Technology Co., Ltd. Graphite paper (GP, 0.1 mm thick) was purchased from Spring Ltd. Ultrapure water was used as the solvent, and the resistivity was 18 MΩ·cm.

[0071] Na {Mo 132 It is prepared by a method including the following steps: 0.176 g of sodium molybdate and 0.1 g of sodium acetate were dissolved in 15 mL of ultrapure water. 200 μL of 1 mol / L sulfuric acid solution (using ultrapure water as solvent) was added, and the mixture was stirred for 0.5 h until the solution turned blue. The solution was then transferred to a polytetrafluoroethylene-lined reactor and heated to 147 °C with continuous stirring for 4 days. The resulting cooled solution was placed in a 15 mL beaker, kept open, and stored for approximately 15 days. Blackish-red crystals were obtained, which were washed with ethanol to obtain Na. 42 [Mo VI 72 Mo V 60 O 372 (CH3COO) 30 (H2O) 72 ], recorded as Na {Mo 132}

[0072] Na {Mo} was tested using an X-ray diffractometer 132 The X-ray diffraction pattern of} is as follows: Figure 1 As shown, by Figure 1 It can be seen that the present invention has successfully synthesized Na{Mo 132The compound has the molecular formula Na. 42 [Mo VI 72 Mo V 60 O 372 (CH3COO) 30 (H2O) 72 ].

[0073] Example 1 This example provides a flexible and stretchable p-type ion thermoelectric gel device, including a first electrode, a p-type ion thermoelectric gel unit, and a second electrode connected in series. Both the first and second electrodes are AgNWs@Au / PDMS electrodes. The AgNWs@Au / PDMS electrode consists of a polydopamine-modified PDMS thin film layer and a mixed conductive layer loaded on the polydopamine-modified PDMS thin film layer. The mixed conductive layer consists of silver nanowires and gold particles, with the gold particles coating the surface of the silver nanowires.

[0074] p-type ionothermal gel units include a gel matrix and Na·Mo distributed within the gel matrix. 132} and Ti3C2T x Na·{Mo 132 The concentration of Ti3C2T in the gel matrix was 0.000421 mol / L. x The concentration in the gel matrix is ​​1.5 g / L, and the gel matrix contains polyacrylic acid and water.

[0075] Reference Figure 2 The fabrication process flow diagram in the image illustrates a method for fabricating a flexible and stretchable p-type ion thermoelectric gel device. The specific steps are as follows: (1) Measure 2 mL of acrylic acid, 0.04 g of N,N'-methylenebisacrylamide (MBAA), and 0.015 g of Na·{Mo 132 (its final concentration in the p-type ion thermogel unit was 0.000421 mol / L), and 0.015 g Ti3C2T x (The final concentration of the substance in the p-type ionic thermoelectric gel unit is 1.5 g / L) and 0.15 g of potassium persulfate were added to 8 mL of ultrapure water, and then 0.05 mL of BIS was added to the above solution to obtain a mixture; then, the mixture was placed in an oven at 333 K for 30 minutes to polymerize and form a p-type ionic thermoelectric gel unit. (2) First, the prepared polydimethylsiloxane (PDMS) film (approximately 94 μm thick) was immersed in a polydopamine solution for surface modification; then, silver nanowires with a concentration of 2.0 mg / mL were spin-coated onto the modified PDMS film to form a conductive network; finally, a gold layer was sputtered onto the surface of the silver nanowire / PDMS electrode using an evaporation coating device to obtain the AgNWs@Au / PDMS electrode.

[0076] (3) An Ecoflex silicone elastomer substrate with a thickness of 2 mm and a pre-defined hollow structure was prepared using a mold forming method. A p-type ion thermogel unit with dimensions of 1 cm × 1 cm × 0.2 cm was precisely embedded into the hollow area of ​​the substrate. A first electrode | p-type ion thermogel unit | second electrode was formed by assembling AgNWs@Au / PDMS flexible electrode with the p-type ion thermogel unit. Finally, the assembled ion thermogel device was encapsulated using an Ecoflex film prepared by a spinometer (Beijing Zhongke Saide, KW-4A).

[0077] The flexible, stretchable p-type ionotropic thermogel prepared in this example was subjected to tensile, bending, and torsion tests, specifically as follows: Figure 3 As shown, where, Figure 3 (a) in the figure represents the initial state of the flexible and stretchable p-type ionic thermogel; Figure 3 (b) in the figure represents the stretched state (50%) of the flexible stretchable p-type ion thermoelectric gel. Figure 3 (c) in the figure represents the bending state of the flexible and stretchable p-type ionic thermogel; Figure 3 In the figure, (d) represents the tortuous state of the flexible, stretchable p-type ionothermal gel; from Figure 3 It can be seen that the flexible stretchable p-type ionic thermoelectric gel in this example did not break under stretching, bending and twisting conditions, and no obvious cracks or delamination were observed. This shows that the flexible stretchable p-type ionic thermoelectric gel of the present invention has excellent flexibility.

[0078] Example 2 The flexible and stretchable p-type ion thermoelectric gel device in this example differs from that in Example 1 in that the first electrode and the second electrode are different. In this example, the first electrode is an AgNWs@Au / PDMS electrode, and the second electrode is a Gp@Au electrode, which is graphite paper with a gold-plated surface.

[0079] This example provides a method for preparing a flexible and stretchable np-type ion thermoelectric gel device, which differs from Example 1 in that: in step (3) of this example, the electrode is prepared using the following raw materials: first, the prepared PDMS film (thickness of about 94 μm) is immersed in a polydopamine solution for surface modification; then, silver nanowires with a concentration of 2.0 mg / mL are spin-coated on the modified film to form a conductive network; finally, gold layers are sputtered on the AgNWs / PDMS electrode and the Gp electrode respectively to obtain the AgNWs@Au / PDMS electrode and the Gp@Au electrode.

[0080] Example 3 The flexible and stretchable p-type ion thermoelectric gel device in this example differs from that in Example 1 in that both the first and second electrodes are electrode materials after being stretched and deformed by 50%.

[0081] This example provides a method for preparing a flexible and stretchable p-type ion thermoelectric gel device, which differs from the preparation method in Example 1 in that: the prepared PDMS film (approximately 94 μm thick) is immersed in a polydopamine solution for surface modification; subsequently, silver nanowires with a concentration of 2.0 mg / mL are spin-coated onto the modified film to form a conductive network; finally, a gold layer is sputtered onto the surface of the silver nanowire / PDMS electrode using an evaporation deposition device to obtain an AgNWs@Au / PDMS electrode, which is then stretched and deformed by 50%.

[0082] Example 4 This example provides an n-type ion thermoelectric gel device, which is formed by connecting a first electrode, an n-type ion thermoelectric gel unit, and a second electrode in series. Both the first and second electrodes are AgNWs@Au / PDMS electrodes. The AgNWs@Au / PDMS electrode consists of a polydopamine-modified PDMS thin film layer and a mixed conductive layer loaded on the polydopamine-modified PDMS thin film layer. The mixed conductive layer consists of silver nanowires and gold particles. The gold particles are coated on the surface of the silver nanowires.

[0083] n-type gel units include a gel matrix and I-type gels distributed within the gel matrix. - / I3 - Redox couple and potassium chloride; I - / I3 - Derived from potassium iodide / iodine, the gel matrix contains polymethacrylic acid and water.

[0084] Reference Figure 2 The preparation process flow diagram in the image illustrates a method for preparing a flexible and stretchable n-type ionic thermogel. The specific steps are as follows: (1) Measure 4 mL of methacrylic acid, 0.23 g of potassium chloride (with a final concentration of 0.3 mol / L in the n-type ion thermogel), and 1 g of 3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate and add them to 6 mL of ultrapure water. Add 0.2 wt.% 2-hydroxy-2-methylphenylacetone to the above solution. Pour the mixture into a mold and irradiate it under ultraviolet light for 3 hours to form a hydrogel. Subsequently, dissolve potassium iodide and iodine (with a final total concentration of 5 mmol / L in the n-type ion thermogel) in ultrapure water at a molar ratio of 2:1 to prepare I - / I3 - The hydrogel was immersed in the solution for 1 hour to obtain the thermogel, namely the n-type ionic thermogel. (2) First, the prepared polydimethylsiloxane (PDMS) film (approximately 94 μm thick) was immersed in a polydopamine solution for surface modification; then, silver nanowires with a concentration of 2.0 mg / mL were spin-coated onto the modified PDMS film to form a conductive network; finally, a gold layer was sputtered onto the surface of the silver nanowire / PDMS electrode using an evaporation coating device to obtain the AgNWs@Au / PDMS electrode.

[0085] (3) An Ecoflex silicone elastomer substrate with a thickness of 2 mm and a pre-defined hollow structure was prepared using a mold forming method. An n-type ion thermogel unit with dimensions of 1 cm × 1 cm × 0.2 cm and a p-type ion thermogel unit with dimensions of 1 cm × 1 cm × 0.2 cm were precisely embedded into the hollow area of ​​the substrate. A first electrode | n-type ion thermogel unit | second electrode was formed by assembling an AgNWs@Au / PDMS flexible electrode with the n-type ion thermogel unit. Finally, the assembled ion thermogel device was encapsulated using an Ecoflex thin film prepared by a spinometer (Beijing Zhongke Saide, KW-4A).

[0086] Example 5 This example provides an np-type ion thermoelectric gel device, which is formed by connecting a first electrode, an np-type ion thermoelectric gel unit, and a second electrode in series. Both the first and second electrodes are AgNWs@Au / PDMS electrodes. The AgNWs@Au / PDMS electrode consists of a polydopamine-modified PDMS thin film layer and a mixed conductive layer loaded on the polydopamine-modified PDMS thin film layer. The mixed conductive layer consists of silver nanowires and gold particles. The gold particles are coated on the surface of the silver nanowires.

[0087] The np-type ion thermoelectric gel unit is composed of p-type ion thermoelectric gel and n-type ion thermoelectric gel connected in series; the p-type ion thermoelectric gel includes a gel matrix and Na·Mo distributed in the gel matrix. 132} and Ti3C2T x Na·{Mo 132 The concentration of Ti3C2T in the gel matrix was 0.000421 mol / L. x The concentration in the gel matrix is ​​1.5 g / L, and the gel matrix contains polyacrylic acid and water.

[0088] The second gel comprises a gel matrix and I distributed within the gel matrix. - / I3 - Redox couple and potassium chloride; I - / I3 - Derived from potassium iodide / iodine, the gel matrix contains polymethacrylic acid and water.

[0089] Reference Figure 2 The fabrication process flow diagram in the image illustrates a method for fabricating a flexible and stretchable NP-type ion thermoelectric gel device. The specific steps are as follows: (1) Measure 2 mL of acrylic acid, 0.04 g of N,N'-methylenebisacrylamide (MBAA), and 0.015 g of Na·{Mo 132 (its final concentration in the p-type ion thermogel unit was 0.000421 mol / L), and 0.015 g Ti3C2T x (The final concentration of the substance in the p-type ionic thermoelectric gel unit is 1.5 g / L) and 0.15 g of potassium persulfate are added to 8 mL of ultrapure water, and then 0.05 mL of BIS is added to the above solution to obtain a mixture; then, the mixture is placed in an oven at 333 K for 30 minutes to polymerize and form a p-type ionic thermoelectric gel, i.e., p-type ionic thermoelectric gel. (2) Measure 4 mL of methacrylic acid, 0.23 g of potassium chloride (with a final concentration of 0.3 mol / L in the n-type ion thermogel), and 1 g of 3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate and add them to 6 mL of ultrapure water. Add 0.2 wt.% 2-hydroxy-2-methylphenylacetone to the above solution. Pour the mixture into a mold and irradiate it under ultraviolet light for 3 hours to form a hydrogel. Subsequently, dissolve potassium iodide and iodine (with a final total concentration of 5 mmol / L in the n-type ion thermogel) in ultrapure water at a molar ratio of 2:1 to prepare I - / I3 - The solution was prepared, and the hydrogel was immersed in the solution for 1 hour to obtain the n-type ionic thermoelectric gel, i.e., the n-type ionic thermoelectric gel. (3) First, the prepared polydimethylsiloxane (PDMS) film (approximately 94 μm thick) was immersed in a polydopamine solution for surface modification; then, silver nanowires with a concentration of 2.0 mg / mL were spin-coated onto the modified PDMS film to form a conductive network; finally, a gold layer was sputtered onto the surface of the silver nanowire / PDMS electrode using an evaporation coating device to obtain the AgNWs@Au / PDMS electrode.

[0090] (4) An Ecoflex silicone elastomer substrate with a thickness of 2 mm and a pre-defined hollow structure was prepared using a mold forming method. An n-type ionothermal gel unit with dimensions of 1 cm × 1 cm × 0.2 cm and a p-type ionothermal gel unit with dimensions of 1 cm × 1 cm × 0.2 cm were precisely embedded into the hollow area of ​​the substrate. An AgNWs@Au / PDMS flexible electrode and an np-type ionothermal gel unit were assembled to form a first electrode | np-type ionothermal gel unit | second electrode, where the gel is composed of p-type and n-type ionothermal gels connected in series. Finally, the assembled ionothermal gel device was encapsulated using an Ecoflex film prepared by a spinometer (Beijing Zhongke Saide, KW-4A).

[0091] Example 6 This example provides a wearable device, which is a planar stretchable integrated wearable thermoelectric device formed by connecting eight np-type ion thermoelectric gel devices from Example 5 in series with AgNWs@Au / PDMS electrodes and seamlessly encapsulating them with Ecoflex elastomer.

[0092] Example 7 This example provides a thermoelectric power generation device, which is formed by connecting eight np-type ion thermoelectric gel devices from Example 5 in series via AgNWs@Au / PDMS electrodes.

[0093] Performance testing: When testing the open-circuit voltage of the flexible, stretchable p-type ion thermoelectric gel devices of Examples 1-3 at an initial temperature of 303 K, the hot-end temperature was consistently higher than the cold-end temperature. The cold-end temperature was kept constant at 303 K, while the hot-end temperature was set to be 2 K and 4 K higher than the cold-end temperature, respectively. The first electrode was tightly connected to the hot-end, and the second electrode was tightly connected to the cold-end. By measuring the open-circuit voltage at different temperature differences and performing linear fitting on the relationship between the open-circuit voltage and the temperature difference, the slope of the resulting straight line represents the total thermoelectric potential of the thermoelectric gel battery. The thermoelectric potential test graphs for Examples 1-3 are shown below. Figure 4As shown, the open-circuit voltage of the fabricated flexible and stretchable p-type ion thermoelectric gel device corresponds to the temperature difference. The slope of the linear fit is the corresponding thermoelectric potential, where the corresponding thermoelectric potential of Example 1 (0% strain) is 31.2 mV·K. -1 The corresponding thermoelectric potential for Example 2 (0% strain) is 26.2 mV·K. -1 The corresponding thermoelectric potential for Example 3 (50% strain) is 30.3 mV·K. -1 The experimental results above demonstrate that the gold-coated flexible electrode (AgNWs@Au / PDMS) not only solves the problem of insufficient performance of traditional flexible electrodes, but also surpasses the performance of the rigid reference electrode (Gp@Au). Data shows that AgNWs@Au / PDMS maintains a high and stable thermoelectric potential at 50% strain, proving that through optimized interfacial chemistry and mechanical structure, it significantly improves thermoelectric conversion efficiency while achieving high device stretchability, thus resolving the core contradiction in the field of flexible electronics where "flexibility" and "high performance" are mutually exclusive.

[0094] The normalized power density performance of the flexible, stretchable p-type ion thermoelectric gel devices of Examples 1-2 was tested. During the test, the devices were kept at a constant temperature (T=313 K) and a constant load ( R Under conditions of 12kΩ, performing a complete charge-discharge cycle on the battery and simultaneously recording thermal conductivity, dimensions, temperature, time, and voltage and current data throughout the discharge process allows for the calculation of normalized power density and efficiency. Specific results are as follows: Figure 5 As shown. By Figure 5 It can be seen that the flexible and stretchable p-type ion thermoelectric gel device of Example 1 (i.e. Figure 5 The normalized power density of AgNWs@Au / PDMS is 3.6 mW / (m²). 2 K 2 ), the flexible stretchable p-type ion thermoelectric gel device of Example 2 (i.e. Figure 5 The normalized power density of Gp@Au is 2.2 mW / (m²). 2 K 2 The above experimental results show that the gold-coated flexible electrode system (AgNWs@Au / PDMS) used in this invention not only achieves the stretchability of the device, but also surpasses the rigid electrode (Gp@Au) in terms of power output per unit temperature difference, demonstrating the synergistic breakthrough of this device in terms of flexibility and high performance.

[0095] The flexible, stretched n-type ion thermoelectric gel from Example 4 was subjected to tensile strains of 0%, 25%, and 50%. When testing the open-circuit voltage of the thermoelectric gel battery at an initial temperature of 303 K, the hot-end temperature was consistently higher than the cold-end temperature. The cold-end temperature was kept constant at 303 K, while the hot-end temperature was set to be 2 K and 4 K higher than the cold-end temperature, respectively. The first electrode was tightly connected to the hot-end, and the second electrode was tightly connected to the cold-end. By measuring the open-circuit voltage at different temperature differences and linearly fitting the relationship between the open-circuit voltage and the temperature difference, the slope of the resulting straight line represents the measured total thermoelectric potential of the thermoelectric gel battery. Figure 6 As shown, the thermoelectric potentials corresponding to 0%, 25%, and 50% tensile strain in Example 4 are -5.7 mV·K, respectively. -1 -5.1 mV·K -1 -4.8mV·K -1 The increase in tensile strain resulted in a slight decrease in the absolute value of the thermoelectric potential of approximately 15.8%, indicating that strain gently weakens its temperature difference-potential conversion capability, but the core performance does not drop drastically. Furthermore, the negative thermoelectric potential aligns with the ion transport characteristics of n-type materials, confirming the effectiveness of its n-type design. The stable quantitative output at 25% and 50% strain demonstrates that the gel network structure did not suffer irreversible damage under stretching, the ion transport pathways remained continuous, and the interfacial bonding between the electrode and the gel did not detach due to deformation, exhibiting good flexibility and stability. Combined with its superior ion thermoelectric potential level, this gel is suitable for applications requiring small temperature difference power generation (such as using the temperature difference between the human body and the environment) in wearable devices and flexible sensors. Simultaneously, the cold end temperature T under these three stretching states... C =313K, hot end temperature T H During the thermal discharge stage at 317K (temperature difference ΔT = 4K) and a load resistance R = 12kΩ, an n-type gel battery was tested, and the time-varying voltage V(t) and current I(t) curves were obtained, as detailed below. Figures 7-9 As shown, the n-type i-TE gel battery with AgNWs@Au / PDMS as the flexible electrode exhibits a typical trend of output voltage and power density gradually increasing with current density and then orderly decreasing after reaching the peak under progressive tensile strain conditions of 0%, 25%, and even 50%. This highly consistent electrical performance evolution clearly demonstrates that even when subjected to different degrees of tensile deformation, the core electrical performance of this flexible device remains consistent, fully showcasing its excellent and reliable flexible operation stability.

[0096] An integrated, planar, stretchable, wearable thermoelectric device (i.e., the wearable device in Example 6) was constructed by sequentially connecting and integrating eight flexible, stretchable np-type ion thermoelectric gel units from Example 5 using AgNWs@Au / PDMS flexible electrodes and seamlessly encapsulating them with Ecoflex elastomer. This device was then worn directly on the wrist, and its voltage was tested under different conditions. Specific test results are as follows: Figure 10 As shown, Figure 10 The inset image shows the wearable device in its actual state when worn directly on the wrist. Under dynamic bending and skin contact, the device generates a stable output voltage close to 1 V (approximately 968 mV) utilizing only a small temperature difference of about 2–3 K between body temperature and the environment, and maintains 98% of its initial performance compared to its flat state. These experimental results demonstrate that the device not only possesses the ability to efficiently collect low-grade human body heat energy, but also exhibits excellent mechanical adaptability and output stability in real-world wearable scenarios, providing crucial validation for its potential for practical self-powered applications.

[0097] The flexible, stretchable np-type ion thermoelectric gel device from Example 5 was fabricated into a thermoelectric power generation device. Eight np-type ion thermoelectric gel units from Example 5 were connected in series using AgNWs@Au / PDMS flexible electrodes to construct an integrated thermoelectric power generation module (i.e., the thermoelectric power generation device in Example 7). Its open-circuit voltage was then tested, and the specific test results are as follows: Figure 11 As shown, the open-circuit voltage and maximum output power density of the thermoelectric generator were then tested when a stable temperature difference of 10K was applied between the hot and cold ends. Specifically, as shown... Figure 12 As shown in the diagram, in this module, the electrodes at both ends are in close contact with an external heat source and a cold source, respectively, forming clearly defined hot and cold ends. By precisely controlling the temperature difference between the hot and cold ends, active regulation of the thermoelectric conversion output can be achieved. Experiments showed that when the entire thermoelectric generator was placed at an ambient temperature of 313K (approximately 40℃) and a stable temperature difference of 10K was applied between the hot and cold ends, its open-circuit voltage reached 3.9V (e.g., ...). Figure 11 As shown), the maximum output power density is 205 mW / m² (e.g. Figure 12 (As shown). This result demonstrates that the thermoelectric power generation device can simultaneously provide high voltage and power output under practical temperature difference conditions, exhibiting excellent energy harvesting capabilities. Traditional electronic semiconductor thermoelectric materials require hundreds or thousands of thermoelectric units to achieve a voltage of 1 V, while the flexible stretchable np-type ion thermoelectric gel device of this invention only requires 8 pairs in series and can achieve a voltage of 3.9 V at a temperature difference of 10 K, exhibiting very high voltage and power output.

[0098] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An ion-thermoelectric gel device, characterized in that: It includes at least one device; the device includes a first electrode, an ion thermoelectric gel unit, and a second electrode arranged in series; The first electrode and / or the second electrode include a substrate layer and a conductive layer stacked together; the substrate layer is made of an elastic polymer material; The conductive layer is made of conductive particles and conductive nanowires; the conductive particles coat the surface of the conductive nanowires, and the materials of the conductive particles and the conductive nanowires are each independently selected from at least one of gold, silver, platinum, and copper.

2. The ion thermoelectric gel device according to claim 1, characterized in that: The ion thermoelectric gel unit includes n-type ion thermoelectric gel, p-type ion thermoelectric gel or np-type ion thermoelectric gel. The np-type ion thermoelectric gel includes an n-type ion thermoelectric gel and a p-type ion thermoelectric gel arranged in series.

3. The ion thermoelectric gel device according to claim 1, characterized in that: The p-type ion thermoelectric gel comprises a first gel matrix, inorganic two-dimensional nanomaterials, a first metal salt, and water; the inorganic two-dimensional nanomaterials, the first metal salt, and water are all distributed in the first gel matrix; And / or, The n-type ion thermoelectric gel comprises a second gel matrix, a second metal salt, a redox couple, and water; the redox couple, the second metal salt, and water are all distributed in the second gel matrix.

4. The ion thermoelectric gel device according to claim 3, characterized in that: The first metal salt is selected from Na 42 [Mo VI 72 Mo V 60 O 372 (CH3COO) 30 (H2O) 72 ]、K 42 [Mo VI 72 Mo V 60 O 372 (CH3COO) 30 (H2O) 72 ]、 (NH4) 80 [Mo V 180 Mo VI 80 (OH) 60 O 700 ] At least one of 240H2O; And / or, the second metal salt is selected from at least one of sodium sulfate, sodium carbonate, potassium carbonate, potassium chloride, sodium nitrate, potassium sulfate, sodium chloride, and potassium nitrate; And / or, the material of the redox couple is selected from at least one of K3Fe(CN)6 / K4Fe(CN)6, Na3Fe(CN)6 / Na4Fe(CN)6, Na2SO4 / Na2SO3, K2SO4 / K2SO3, KI / I3, and NaI / I3; And / or, the inorganic two-dimensional nanomaterial is an MXene material; And / or, the material of the first gel matrix includes at least one of gelatin, polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, polyethylene glycol, and polyacrylamide; And / or, the material of the second gel matrix includes at least one of gelatin, polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, polyethylene glycol, and polyacrylamide.

5. The ion thermoelectric gel device according to claim 3, characterized in that: The concentration of the first metal salt in the p-type ion thermoelectric gel is less than the concentration of the second metal salt in the n-type ion thermoelectric gel; preferably, the molar concentration of the first metal salt in the p-type ion thermoelectric gel is 0.0002~0.0006 mol / L. Preferably, the molar concentration of the second metal salt in the n-type ion thermoelectric gel is (0.1~1) mol / L.

6. The ion thermoelectric gel device according to claim 1, characterized in that: The mass-to-volume ratio of water in the first gel matrix and the p-type ionic thermoelectric gel is 1 g: (5-20) mL; And / or, the mass concentration of the inorganic two-dimensional nanomaterial in the p-type ion thermoelectric gel is 1~2 g / L; And / or, the molar concentration of the redox couple in the n-type ion thermoelectric gel is (3-8) mmol / L; And / or, the mass-to-volume ratio of the second gel matrix to the water in the n-type ionic thermoelectric gel is 1 g: (1-5) mL.

7. The ion thermoelectric gel device according to claim 1, characterized in that: The first electrode or the second electrode is conductive graphite paper; the conductive graphite paper includes graphite paper and a conductive material layer selected from at least one of gold, silver, platinum and copper disposed on the surface of the graphite paper.

8. The ion thermoelectric gel device according to any one of claims 1 to 7, characterized in that: The ion thermoelectric gel device can operate stably in a temperature range of 10-80 °C. And / or, when the ion thermoelectric gel device is in operation, the temperature difference between the p-type ion thermoelectric gel and the n-type ion thermoelectric gel is 1~20K.

9. A method for preparing the ion thermoelectric gel device according to any one of claims 1 to 8, characterized in that: Includes the following steps: The first electrode, the ion thermoelectric gel unit, and the second electrode are connected in series to form the electrode.

10. A product, characterized in that: The product includes the ion thermoelectric gel device according to any one of claims 1 to 8; the product includes a thermoelectric generator, a sensor, a battery, or a wearable device.

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