Friction medium material, method of making and use thereof, and tribo-nanogenerators

Abstract

This invention relates to the field of friction materials, and discloses a friction medium material, its preparation method and application, and a triboelectric nanogenerator. The friction medium material is a film material comprising a continuous phase of at least one polymer and at least one filler dispersed in the continuous phase; in the friction medium material, the volume percentage of the filler is 0.01-4.5 vol%. The friction medium material prepared by this invention has a high dielectric constant and a low leakage current. When this friction medium material with a small amount of filler is applied to a nanogenerator, the resulting triboelectric nanogenerator exhibits excellent surface charge density.

Description

Technical Field

[0001] This invention relates to the field of friction materials, specifically to a friction medium material, its preparation method and application, and a triboelectric nanogenerator. Background Technology

[0002] Triboelectric nanogenerators (TENGs) can effectively convert various forms of low-frequency mechanical energy into electrical energy. They have advantages such as high cost-effectiveness, simple manufacturing, flexibility, diverse structural designs, rich material selection, and environmental friendliness, showing great potential in fields such as the Internet of Things, artificial intelligence, and wearable electronics.

[0003] Currently, one of the key problems with TENGs is the low current density and low power density caused by the low surface charge density. Typically, TENGs are composed of triboelectric materials and electrode materials, and the surface charge density is mainly limited by four factors: the charge density of the triboelectric material during initial charging, the charge density during air breakdown, the charge density during the breakdown of the triboelectric layer, and the contact efficiency.

[0004] For triboelectric materials, current methods mainly focus on improving their electrostatic properties through material selection, surface modification, internal filling, and increasing the effective contact area. Charge excitation technology is also employed to overcome the limitations of these electrostatic properties. Commonly used triboelectric materials include FEP, PVC, PTFE, and PVDF, all of which have dielectric constants less than 15 (1 kHz), resulting in low charge density and poor performance in TENG.

[0005] Therefore, there is an urgent need for a type of triboelectric medium material with a high dielectric constant to solve the problem of low surface charge density of TENG. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of low dielectric constant in existing triboelectric materials, and to provide a triboelectric material, its preparation method and application. This triboelectric material has the characteristics of high dielectric constant, low leakage current density and low material thickness. When applied to triboelectric nanogenerators, it can improve the surface charge density of the generator.

[0007] To achieve the above objectives, the first aspect of the present invention provides a friction medium material, wherein the friction medium material is a film material comprising a continuous phase of at least one polymer and at least one filler dispersed in the continuous phase;

[0008] In the friction medium material, the filler has a volume percentage of 0.01-4.5 vol%.

[0009] A second aspect of the present invention provides a method for preparing a friction medium material, comprising the following steps:

[0010] (1) Mix at least one polymer, at least one filler and a solvent to obtain a mixed solution;

[0011] (2) The mixed solution is coated on the substrate, dried, and peeled off to obtain the friction medium material;

[0012] The amount of filler added is 0.01-4.5 vol% of the total volume of the polymer and filler.

[0013] A third aspect of the present invention provides an application of the above-mentioned friction medium material in a triboelectric nanogenerator.

[0014] A fourth aspect of the present invention provides a triboelectric nanogenerator, wherein the generator comprises the aforementioned triboelectric medium material;

[0015] Preferably, at a frequency of 1.4 Hz, the surface charge density of the triboelectric nanogenerator is greater than or equal to 4 mC / m. -2 Preferably greater than or equal to 5mC m -2 More preferably, greater than or equal to 6mC m -2 .

[0016] Through the above technical solutions, the friction medium material, its preparation method, its application, and the triboelectric nanogenerator provided by this invention achieve the following beneficial effects:

[0017] The friction medium material provided by this invention uses at least one polymer as the continuous phase and a small amount of filler dispersed in the continuous phase, thereby improving the dielectric constant of the friction medium material and reducing leakage current. When this friction medium material with a small amount of filler is applied to a nanogenerator, the resulting triboelectric nanogenerator has excellent surface charge density.

[0018] In the preparation method of the friction medium material provided by the present invention, a small amount of filler is added to make the material have a high dielectric constant, and when used as a friction layer of a nanogenerator, it can improve the surface charge density.

[0019] Furthermore, when the friction medium material provided by this invention is applied to a triboelectric nanogenerator, the resulting triboelectric nanogenerator exhibits excellent surface charge density, meeting the material requirements for high-performance triboelectric nanogenerators. Attached Figure Description

[0020] Figure 1 This is a simplified structural diagram of a triboelectric nanogenerator, including a second triboelectric layer (1), a first triboelectric layer (2), a conductive layer (3), and a load (4).

[0021] Figure 2This is a graph showing the dielectric constant of the 1 vol% BTO particles / P(VDF-TrFE-CFE) triboelectric medium material in Example 1 at different frequencies.

[0022] Figure 3 This is a surface charge density diagram (operating frequency 1.4 Hz) of the 1 vol% BTO particles / P (VDF-TrFE-CFE) friction medium material used in Example 1 as the friction layer.

[0023] Figure 4 This is a cross-sectional SEM image of the friction medium material P(VDF-TrFE-CFE) in Comparative Example 1.

[0024] Figure 5 This is a diagram showing the dielectric constant of the triboelectric medium material P(VDF-TrFE-CFE) in Comparative Example 1 at different frequencies.

[0025] Figure 6 This is a surface charge density diagram of the P(VDF-TrFE-CFE) friction medium material used as the friction layer in Comparative Example 1 (operating frequency 1.4Hz). Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] The first aspect of the present invention provides a friction medium material, wherein the friction medium material is a film material comprising a continuous phase of at least one polymer and at least one filler dispersed in the continuous phase;

[0028] In the friction medium material, the filler has a volume percentage of 0.01-4.5 vol%.

[0029] In this invention, the friction medium material uses at least one polymer as the continuous phase and a small amount of filler dispersed in the continuous phase, which can improve the dielectric constant of the friction medium material; when this friction medium material with a small amount of filler is applied to a nanogenerator, the obtained triboelectric nanogenerator has excellent surface charge density.

[0030] Furthermore, in the friction medium material, the filler has a volume percentage of 0.01-3 vol%.

[0031] Furthermore, in the friction medium material, the filler has a volume percentage of 0.1-2 vol%.

[0032] According to the present invention, the packing material is selected from at least one of zero-dimensional packing material, one-dimensional packing material and two-dimensional packing material.

[0033] Furthermore, the packing material is a combination of one-dimensional and two-dimensional packing materials.

[0034] In this invention, when the above-mentioned combined filler is used, it can be uniformly dispersed in the polymer, and at a certain content, the two types of fillers can effectively suppress leakage current, improve the dielectric constant of the friction medium material, and thus improve the surface charge density of the triboelectric nanogenerator.

[0035] According to the present invention, the volume percentage of the one-dimensional packing is 1-70 vol% relative to the total volume of the one-dimensional packing and the two-dimensional packing;

[0036] According to the present invention, the filler is a ceramic material.

[0037] According to the present invention, the average particle size of the zero-dimensional filler is 1-300 nm.

[0038] In this invention, when the zero-dimensional filler meets the above-mentioned particle size requirements, it can be uniformly dispersed in the polymer, thereby increasing the dielectric constant of the friction medium material and increasing the surface charge density of the triboelectric nanogenerator.

[0039] Furthermore, the average particle size of the zero-dimensional filler is 5-200 nm.

[0040] Furthermore, the average particle size of the zero-dimensional filler is 10-100 nm.

[0041] According to the present invention, the zero-dimensional filler is at least one of barium titanate particles, lead titanate particles, lead zirconate titanate particles, calcium copper titanate particles, and strontium titanate particles.

[0042] According to the present invention, the one-dimensional filler has an average length of 1-7 μm and an average diameter of 50-700 nm.

[0043] In this invention, when the morphology of the one-dimensional filler meets the above-mentioned limitations, the interfacial polarization between the filler and the polymer is stronger, thereby increasing the dielectric constant of the triboelectric medium material. Moreover, within the volume percentage range of the filler defined in this invention, the leakage current of the triboelectric medium material can be reduced, thereby increasing the surface charge density of the triboelectric nanogenerator.

[0044] Furthermore, the one-dimensional filler has an average length of 1-5 μm and an average diameter of 50-500 nm.

[0045] Furthermore, the one-dimensional filler has an average length of 2-3 μm and an average diameter of 60-200 nm.

[0046] According to the present invention, the one-dimensional filler is at least one of lead zirconate titanate fiber, calcium copper titanate fiber, barium titanate fiber, and strontium titanate fiber.

[0047] According to the present invention, the average length of the two-dimensional filler is 1-7 μm and the average thickness of the two-dimensional filler is 1-700 nm.

[0048] In this invention, when the morphology of the two-dimensional filler meets the above-mentioned limitations, the interfacial polarization between the filler and the polymer is stronger, thereby increasing the dielectric constant of the triboelectric medium material. Moreover, within the volume percentage range of the filler defined in this invention, the leakage current of the triboelectric medium material can be reduced, thereby increasing the surface charge density of the triboelectric nanogenerator.

[0049] Furthermore, the average length of the two-dimensional filler is 1-5 μm, and the average thickness of the two-dimensional filler is 1-500 nm.

[0050] Furthermore, the average length of the two-dimensional filler is 2-3 μm, and the average thickness of the two-dimensional filler is 50-200 nm.

[0051] According to the present invention, the two-dimensional filler is at least one of strontium titanate nanosheets, barium titanate nanosheets, and lead zirconate titanate nanosheets.

[0052] According to the present invention, the dielectric constant of the polymer is ≥10 at 1 kHz and a thickness of 8±2 μm.

[0053] According to the present invention, the polymer is selected from at least one of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)), poly(vinylidene fluoride-trifluoroethylene-trifluorochloroethylene) (P(VDF-TrFE-CTFE)) and poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene-fluorinated alkyne) (P(VDF-TrFE-CFE-FA)).

[0054] In this invention, when the continuous phase of the friction medium material is selected from the above-mentioned polymer, the dielectric constant of the friction medium material is higher, and the surface charge density of the triboelectric nanogenerator is higher.

[0055] Furthermore, the polymer is a combination of poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) and poly(vinylidene fluoride-trifluoroethylene-trifluorochloroethylene) (P(VDF-TrFE-CTFE)).

[0056] According to the present invention, the mass ratio of poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) to poly(vinylidene fluoride-trifluoroethylene-trifluorochloroethylene) is 1:0.1-9.

[0057] According to the present invention, the weight-average molecular weight of the polymer is 450,000-550,000 g / mol.

[0058] According to the present invention, when the thickness of the friction medium material is 8±2μm, the dielectric constant at 1kHz is ≥45.

[0059] Furthermore, when the thickness of the friction medium material is 8±2μm, the dielectric constant at 1kHz is ≥50.

[0060] Furthermore, when the thickness of the friction medium material is 8±2μm, the dielectric constant at 1kHz is ≥55.

[0061] According to the present invention, the friction medium material is used in an electric field with a strength of 100 MV m. -1 The leakage current density is ≤1×10 -5 A cm -2 .

[0062] Furthermore, the friction medium material is used in an electric field with a strength of 100 MV m. -1 The leakage current density is ≤1×10 -6 Acm -2 .

[0063] Furthermore, the friction medium material is used in an electric field with a strength of 100 MV m. -1 The leakage current density is ≤1×10 -7 A cm -2 .

[0064] According to the present invention, the thickness of the friction medium material is 1-100 μm.

[0065] Furthermore, the thickness of the friction medium material is 1-50 μm.

[0066] Furthermore, the thickness of the friction medium material is 5-10 μm.

[0067] A second aspect of the present invention provides a method for preparing a friction medium material, comprising the following steps:

[0068] (1) Mix at least one polymer, at least one filler and a solvent to obtain a mixed solution;

[0069] (2) The mixed solution is coated on the substrate, dried, and peeled off to obtain the friction medium material;

[0070] The amount of filler added is 0.01-4.5 vol% of the total volume of the polymer and filler.

[0071] In the preparation method of the friction medium material provided by the present invention, a small amount of filler is added to make the friction medium material have a high dielectric constant and suppress the leakage current of the friction medium material. Therefore, when used as the friction layer of a nanogenerator, it can improve the surface charge density.

[0072] In the preparation method of the friction medium material in the second aspect of the present invention, the composition of the polymer and the filler is the same as that of the polymer and the filler described in the first aspect of the present invention. In order to avoid repetition, the present invention will not repeat the description in this second aspect, and those skilled in the art should not understand it as a limitation of the present invention.

[0073] Furthermore, the amount of filler added is 0.01-3 vol% of the total volume of the polymer and filler.

[0074] Furthermore, the amount of filler added is 0.1-2 vol% of the total volume of the polymer and filler.

[0075] According to the present invention, the ratio of the total mass of the filler and polymer to the volume of the solvent is 0.05-0.2 g / mL.

[0076] In this invention, when the amount of solvent meets the above-mentioned limitations, it is more conducive to the preparation of friction medium materials, and the filler in the mixed solution is uniformly dispersed, thereby improving the dielectric constant of the material and having a lower leakage current.

[0077] Furthermore, the ratio of the total mass of the filler and polymer to the volume of the solvent is 0.07-0.18 g / mL.

[0078] Furthermore, the ratio of the total mass of the filler and polymer to the volume of the solvent is 0.1-0.16 g / mL.

[0079] According to the present invention, the solvent is a polar solvent.

[0080] Furthermore, the solvent is selected from at least one of N,N-dimethylformamide (DMF), acetone, and N-methyl-2-pyrrolidone (NMP).

[0081] According to the present invention, the substrate is selected from glass, silicon wafer, aluminum foil, copper foil or PET film.

[0082] According to the present invention, the glass is selected from insulating glass or conductive glass.

[0083] According to the present invention, the conductive glass is ITO glass or FTO glass.

[0084] According to the present invention, the drying temperature is 40-80°C and the drying time is 5-24 hours.

[0085] In one embodiment of the present invention, the coating method includes: casting a mixed solution onto a substrate.

[0086] Furthermore, the height of the scraper used for casting is 100-1000 μm.

[0087] In this invention, the height of the scraper is the thickness of the mixed solution on the substrate, which can be understood as the wet film thickness of the friction medium material.

[0088] In another embodiment of the present invention, the coating method includes spin-coating the mixed solution onto a substrate.

[0089] Furthermore, the spin coating speed is 300-3000 rpm, and the time is 10-120 s.

[0090] A third aspect of the present invention provides an application of the above-mentioned friction medium material in a triboelectric nanogenerator.

[0091] The triboelectric material provided by this invention is applied to triboelectric nanogenerators, and the resulting triboelectric nanogenerators exhibit excellent surface charge density, meeting the material requirements for high-performance triboelectric nanogenerators.

[0092] This invention does not specifically limit the mode of triboelectric nanogenerator. The triboelectric medium material of this invention can be applied to triboelectric nanogenerators in vertical contact-separation mode, horizontal sliding mode, single electrode mode, or independent layer mode.

[0093] In this invention, the influence of the triboelectric nanogenerator mode on the surface charge density is not negligible.

[0094] A fourth aspect of the present invention provides a triboelectric nanogenerator, wherein the generator comprises the aforementioned triboelectric medium material.

[0095] Figure 1 This is a simplified structural schematic diagram of the triboelectric nanogenerator of the present invention. Figure 1 As shown, the triboelectric nanogenerator sequentially comprises a second friction layer, a first friction layer, and a conductive layer, wherein the first friction layer and the conductive layer are bonded together; the first friction layer is selected from the triboelectric medium material of the present invention, the material of the second friction layer is selected from one of copper, aluminum, silver, and gold conductive materials, and the conductive layer is selected from one of copper, aluminum, silver, and gold conductive materials. The nanogenerator also includes a load, which is connected to the first friction layer and the conductive layer through an external circuit.

[0096] In this invention, the materials of the second friction layer and the conductive layer can be the same or different.

[0097] In this invention, the first and second friction layers of the triboelectric nanogenerator undergo longitudinal periodic contact and separation under the action of external force (e.g., Figure 1 (The direction of movement of the first friction layer is indicated by the middle arrow). Electrons can move between the conductive layer and the second friction layer through the external circuit, thereby generating current in the external circuit. When the friction medium material of the present invention is used as the first friction layer, due to the high dielectric constant and low leakage current, the surface charge density of the generator can be increased, which is more conducive to generating current in the external circuit, improving the ability of the triboelectric nanogenerator to output electrical energy, and realizing the purpose of converting mechanical energy into electrical energy by the triboelectric nanogenerator.

[0098] In this invention, the area of ​​the friction medium material in the nanogenerator is not specifically limited and can be adjusted according to actual needs. For example, the area of ​​the friction medium material in the nanogenerator can be 1 cm². 2 -100 cm 2 .

[0099] According to the present invention, at a frequency of 1.4 Hz, the surface charge density of the triboelectric nanogenerator is greater than or equal to 4 mC / m. -2 .

[0100] Furthermore, at a frequency of 1.4 Hz, the surface charge density of the triboelectric nanogenerator is greater than or equal to 5 mCm. -2 .

[0101] Furthermore, at a frequency of 1.4 Hz, the surface charge density of the triboelectric nanogenerator is greater than or equal to 6 mC / m. -2 .

[0102] The present invention will be described in detail below through embodiments.

[0103] The dielectric constant of the friction medium material is calculated after the capacitance is measured by an inductance-capacitance-resistance meter (LCR meter). The test frequency is 1kHz.

[0104] The leakage current density of the triboelectric material was measured using a ferroelectric testing system (Radiant Technologies) with an electric field strength of 100 MV m. -1 .

[0105] The surface charge density of the triboelectric nanogenerator was directly measured using an electrometer (Keithley 6514). The operating frequency of the triboelectric nanogenerator was 1.4 Hz during the test.

[0106] The volume percentage of filler is calculated from the density and mass of the filler and polymer.

[0107] P(VDF-TrFE-CFE) is a commercially available product from Piezotech under the brand name RT-FS, with a weight-average molecular weight of 500,000 g / mol and a density of 1.8 g / m³. 3 .

[0108] P(VDF-TrFE-CTFE) is a commercially available product from Piezotech under the brand name RT-TS, with a molecular weight of 500,000 g / mol and a density of 1.8 g / m³. 3 .

[0109] Barium titanate (BTO) particles are a commercially available product from Aladdin Company, brand name B118840, with an average particle size of 100 nm and a density of 6.017 g / cm³. 3 .

[0110] Barium titanate fiber (BTO fiber) has an average length of 5 μm, an average diameter of 300 nm, and a density of 6.017 g / cm³. 3 The BTO fiber was prepared by electrospinning. Specifically, barium acetate (1.27 g) was dissolved in a mixed solution of acetic acid (10 mL) and anhydrous ethanol (10 mL), and tetrabutyl titanate (1.7 g) was added dropwise in the appropriate stoichiometric ratio, followed by stirring to obtain a homogeneous precursor solution. A certain amount of polyvinylpyrrolidone (PVP) was added at a ratio of 0.06 g / mL to adjust the viscosity of the precursor solution. After electrospinning under an electric field of 1 kV / cm, the fiber was calcined at 550℃ for 2 hours to obtain the BTO fiber.

[0111] Barium titanate nanosheets (BTO nanosheets) were prepared by the molten salt method, with an average diameter of 1 μm, an average thickness of 300 nm, and a density of 6.017 g / cm³. 3 The specific method is as follows: First, Bi₂O₃ and TiO₂ are used as reactants and mixed in a stoichiometric ratio of 2:3. Then, an equal mass of NaCl-KCl mixed salt (molar ratio of 1:1) is added. After mixing thoroughly, the mixture is reacted at 850℃ for 2 hours to synthesize two-dimensional Bi₄Ti₃O₃. 12 Flakes. Then synthesize Bi4Ti3O. 12 Using the nanosheet as a template, weigh BaCO3 at a molar ratio of 1:10 and add an equal mass of NaCl-KCl mixed salt (molar ratio 1:1). After mixing thoroughly, react at 1000℃ for 2 hours. After cleaning, the target BTO nanosheets can be obtained.

[0112] Lead zirconate titanate fiber (PZT fiber) has an average length of 3 μm, an average diameter of 300 nm, and a density of 7.5 g / m³. 3The PZT fiber was prepared by electrospinning. The specific method was as follows: A Zr / Ti stoichiometric ratio of 52 / 48 was used. First, a certain amount of lead acetate trihydrate was weighed and dissolved in glacial acetic acid (2 mL). Then, corresponding amounts of zirconium nitrate pentahydrate, tetrabutyl titanate, 2 mL of acetylacetone, and 8 mL of ethylene glycol methyl ether were added sequentially. After stirring until a clear, orange-red liquid was obtained, PVP was added at a ratio of 0.06 g / mL to adjust the solution viscosity. After electrospinning under an electric field of 1 kV / cm, the solution was calcined at 650℃ for 2 hours to obtain the PZT fiber.

[0113] Strontium titanate nanosheets (STO nanosheets) were synthesized via the molten salt method, with an average diameter of 1 μm, an average thickness of 300 nm, and a density of 4.81 g / m³. 3 The specific method is as follows: First, SrCO3 and TiO2 are used as reactants and mixed in a stoichiometric ratio of 3:2. An equal mass of NaCl-KCl mixed salt (molar ratio 1:1) is added, and the mixture is stirred thoroughly at 1300℃ for 6 hours to synthesize a two-dimensional Sr3Ti2O7 precursor. Then, using the synthesized Sr3Ti2O7 as a template, TiO2 is weighed in a molar ratio of 1:1, and an equal mass of NaCl-KCl mixed salt (molar ratio 1:1) is added. After stirring thoroughly, the mixture is stirred at 1200℃ for 4 hours. After cleaning, the target synthesized STO nanosheets are obtained.

[0114] Calcium copper titanate (CCTO) fiber was prepared by electrospinning according to Example 1 of CN105803579A. Its average length was 3 μm, average diameter was 250 nm, and density was 6.45 g / m³. 3 .

[0115] Example 1

[0116] Weigh 0.02 g of BTO particles and 0.6 g of P(VDF-TrFE-CFE) and dissolve them in 4 mL of DMF solvent. The amount of filler added is 1 vol% of the total volume of the polymer and filler. After stirring evenly, place the mixture on a silicon wafer and adjust the doctor blade height to 200 μm to cast a film. Place it in a drying oven at 70 °C for 10 h, and peel off the film to obtain a 1 vol% BTO particle / P(VDF-TrFE-CFE) triboelectric material with a thickness of 8 μm and a dielectric constant of 56 (1 kHz). Figure 2 As shown. The leakage current density is 5 × 10⁻⁶. -8 A cm -2 (100MV m -1 ).

[0117] By using a friction medium material as a friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 6 mC / m² was achieved. -2The result is as follows Figure 3 As shown.

[0118] Example 2

[0119] Weigh 0.07 g of PZT fiber and 0.56 g of P(VDF-TrFE-CTFE) and dissolve them in 4 mL of DMF solvent, stirring until homogeneous. The filler added is 3 vol% of the total volume of the polymer and filler. Place the mixed solution on an ITO glass plate and spin-coat at 800 rpm for 30 s. Dry it in a 40°C oven for 7 h, then peel off the film to obtain a 3 vol% PZT fiber / P(VDF-TrFE-CTFE) triboelectric medium material with a thickness of approximately 20 μm. When the thickness of this triboelectric medium material is 20 μm, its dielectric constant is 62 (1 kHz) and its leakage current density is 4.1 × 10⁻⁶. -7 A cm -2 (100MV m -1 ).

[0120] A friction medium material is used as the friction layer in a TENG (Transient Induction Heat Pump) for horizontal sliding mode. Its surface charge density reaches 4.3 mC / m. -2 .

[0121] Example 3

[0122] 0.08 g of BTO particles and 0.6 g of P(VDF-TrFE-CFE) were weighed and dissolved in 4 mL of DMF solvent. The amount of filler added was 4 vol% of the total volume of the polymer and filler. After stirring evenly, the mixture was placed on a silicon wafer, and the doctor blade height was adjusted to 200 μm to cast a film. The film was dried in a drying oven at 70 °C for 10 h. The film was then peeled off to obtain a 4 vol% BTO particle / P(VDF-TrFE-CFE) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 63 (1 kHz), and a leakage current density of 7 × 10⁻⁶. -7 A cm -2 (100MV m -1 ).

[0123] By using a friction medium material as a friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 4 mC / m² was achieved. -2 .

[0124] Example 4

[0125] 0.01 g of BTO fiber, 0.01 g of BTO nanosheets, and 0.6 g of P(VDF-TrFE-CFE) were weighed and dissolved in 4 mL of DMF solvent. The filler was added at 1 vol% of the total volume of the polymer and filler, with a volume ratio of BTO fiber to BTO nanosheets of 1:1. After stirring evenly, the mixture was placed on a silicon wafer, and the doctor blade height was adjusted to 200 μm to cast a film. The film was then dried in a 70°C oven for 10 h. The film was then peeled off to obtain a 1 vol% BTO fiber / nanosheet / P(VDF-TrFE-CFE) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 58 (1 kHz), and a leakage current density of 1.5 × 10⁻⁶. -8 A cm -2 (100MVm -1 ).

[0126] By using a friction medium material as the friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 6.3 mC / m² was achieved. -2 .

[0127] Example 5

[0128] 0.01 g of BTO fiber, 0.01 g of BTO nanosheets, 0.3 g of P(VDF-TrFE-CFE), and 0.3 g of P(VDF-TrFE-CTFE) were weighed and dissolved in 4 mL of DMF solvent. The filler was added at 1 vol% of the total volume of the polymer and filler, with a volume ratio of BTO fiber to BTO nanosheets of 1:1. After stirring evenly, the mixture was placed on a silicon wafer, and the doctor blade height was adjusted to 200 μm to cast a film. The film was dried in a 70℃ drying oven for 10 h. The film was then peeled off to obtain a 1 vol% BTO fiber / nanosheet / P(VDF-TrFE-CFE) / P(VDF-TrFE-CTFE) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 59 (1 kHz), and a leakage current density of 1 × 10⁻⁶. -8 A cm -2 (100MV m -1 ).

[0129] By using a friction medium material as the friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 6.4 mC / m² was achieved. -2 .

[0130] Example 6

[0131] The triboelectric material was prepared according to the method of Example 5, except that the amount of filler added was 0.01 vol% of the total volume of the polymer and filler. This resulted in a triboelectric material with a thickness of approximately 8 μm, consisting of 0.01 vol% BTO fiber / nanosheet / P(VDF-TrFE-CFE) / P(VDF-TrFE-CTFE), a dielectric constant of 52 (1 kHz), and a leakage current density of 5 × 10⁻⁶. -8 A cm -2 (100MV m -1 ).

[0132] By using a friction medium material as a friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 5 mC / m² was achieved. -2 .

[0133] Example 7

[0134] The triboelectric material was prepared according to the method of Example 5, except that the amount of filler added was 4 vol% of the total volume of the polymer and filler. This resulted in a 4 vol% BTO fiber / nanosheet / P(VDF-TrFE-CFE) / P(VDF-TrFE-CTFE) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 63 (1 kHz), and a leakage current density of 6 × 10⁻⁶. -7 A cm -2 (100MVm -1 ).

[0135] By using a friction medium material as the friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 4.1 mC / m² was achieved. -2 .

[0136] Example 8

[0137] Weigh 0.02 g of BTO fiber, 0.3 g of P(VDF-TrFE-CFE), and 0.3 g of P(VDF-TrFE-CTFE) and dissolve them in 4 mL of DMF solvent. The amount of filler added is 1 vol% of the total volume of the polymer and filler. After stirring evenly, place the mixture on a silicon wafer and adjust the doctor blade height to 200 μm to cast a film. Place it in a drying oven at 70 °C for 10 h, and peel off the film to obtain a 1 vol% BTO fiber / P(VDF-TrFE-CFE) / P(VDF-TrFE-CTFE) triboelectric medium material with a thickness of about 8 μm, a dielectric constant of 58 (1 kHz), and a leakage current density of 4 × 10⁻⁶. -8 A cm -2 (100MV m -1 ).

[0138] By using a friction medium material as the friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 6.1 mC / m² was achieved. -2 .

[0139] Example 9

[0140] 0.02 g of BTO nanosheets, 0.3 g of P(VDF-TrFE-CFE) and 0.3 g of P(VDF-TrFE-CTFE) were weighed and dissolved in 4 mL of DMF solvent. The amount of filler added was 1 vol% of the total volume of the polymer and filler. After stirring evenly, the mixture was placed on a silicon wafer, and the doctor blade height was adjusted to 200 μm to cast a film. The film was dried in a drying oven at 70 °C for 10 h. The film was then peeled off to obtain a 1 vol% BTO nanosheet / P(VDF-TrFE-CFE) / P(VDF-TrFE-CTFE) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 58 (1 kHz), and a leakage current density of 3 × 10⁻⁶. -8 A cm -2 (100MV m -1 ).

[0141] By using a friction medium material as the friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 6.2 mC / m² was achieved. -2 .

[0142] Comparative Example 1

[0143] 0.75 g of P(VDF-TrFE-CFE) was dissolved in 6 mL of DMF solvent. After stirring evenly, the mixture was placed on aluminum foil, and the doctor blade height was adjusted to 200 μm for casting. The film was then dried in a 60℃ drying oven for 5 hours. The film was then peeled off to obtain a P(VDF-TrFE-CFE) friction medium material with a thickness of approximately 8 μm. The cross-sectional SEM image is shown below. Figure 4 As shown, its dielectric constant is 50 (1kHz), and the dielectric constants at different frequencies are as follows. Figure 5 As shown, the leakage current density is 9×10 -7 A cm -2 (100MV m -1 ).

[0144] P(VDF-TrFE-CFE) thin films were applied to TENGs in a vertical contact-separation mode. Using the P(VDF-TrFE-CFE) thin film as a friction layer, combined with charge excitation technology, the surface charge density reached 3.5 mC / m². -2 The result is as follows Figure 6 As shown.

[0145] Comparative Example 2

[0146] 0.303 g of STO nanosheets and 1.02 g of P(VDF-TrFE-CTFE) were weighed and dissolved in 6 mL of NMP solvent. After stirring evenly, the mixture was placed on a glass plate and spin-coated at 2000 rpm for 50 s. The mixture was then dried in a 70 °C oven for 12 h. The film was peeled off to obtain a 10 vol% STO nanosheet / P(VDF-TrFE-CTFE) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 72 (1 kHz), and a leakage current density of 1 × 10⁻⁶. -6 A cm -2 (100MV m -1 ).

[0147] TENG was performed using a single-electrode mode. A 10 vol% STO nanosheet / P(VDF-TrFE-CTFE) high-dielectric film was used as the tribological layer, achieving a surface charge density of 3.5 mC / m². -2 .

[0148] Comparative Example 3

[0149] 0.376 g of CCTO fiber and 2 g of P(VDF-TrFE-CFE) were weighed and dissolved in 10 mL of DMF solvent. After stirring evenly, the mixture was placed on a copper foil, and the doctor blade height was adjusted to 200 μm to cast a film. The film was then dried in an oven at 80 °C for 24 h. The film was then peeled off to obtain a 7 vol% CCTO fiber / P(VDF-TrFE-CFE) triboelectric dielectric material with a thickness of approximately 8 μm, a dielectric constant of 75 (1 kHz), and a leakage current density of 8 × 10⁻⁶. -7 A cm -2 (100MV m -1 ).

[0150] TENG employs an independent layer mode. The 7 vol% CCTO fiber / P(VDF-TrFE-CFE) high-dielectric film, used as the tribological layer, achieves a surface charge density of 3.7 mC / m². -2 .

[0151] Comparative Example 4

[0152] 0.3 g of P(VDF-TrFE) was dissolved in 6 mL of DMF solvent. After stirring until homogeneous, the mixture was placed on an FTO glass substrate, and the doctor blade height was adjusted to 200 μm for casting. The substrate was then dried in a 40°C oven for 24 h. The film was then peeled off to obtain a P(VDF-TrFE) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 30 (1 kHz), and a leakage current density of 1 × 10⁻⁶. -7 A cm -2 (100MV m-1 ).

[0153] TENG employs a vertical contact-separation mode. Using a P(VDF-TrFE) high-dielectric thin film as the tribological layer, combined with charge excitation technology, the surface charge density reaches 1.9 mC / m². -2 .

[0154] Comparative Example 5

[0155] 1.2 g of P(VDF-TrFE-CFE-FA) was dissolved in 6 mL of DMF solvent. After stirring until homogeneous, the mixture was placed on aluminum foil, and the doctor blade height was adjusted to 200 μm for casting. The film was then dried in a 50°C oven for 24 h. The film was then peeled off to obtain a P(VDF-TrFE-CFE-FA) triboelectric material with a thickness of approximately 8 μm, a dielectric constant of 45 (1 kHz), and a leakage current density of 1 × 10⁻⁶. -7 A cm -2 (100MV m -1 ).

[0156] TENG employs a vertical contact-separation mode. Using a P(VDF-TrFE-CFE-FA) high-dielectric thin film as the tribological layer, combined with charge excitation technology, a high surface charge density of 3.9 mC / m² is achieved. -2 .

[0157] Comparative Example 6

[0158] 0.3 g of P(VDF-TrFE-CFE) and 0.3 g of P(VDF-TrFE-CTFE) were weighed and dissolved in 4 mL of DMF solvent. After stirring evenly, the mixture was placed on a silicon wafer, and the doctor blade height was adjusted to 200 μm to cast a film. The film was then dried in a 70℃ drying oven for 10 h. The film was then peeled off to obtain a P(VDF-TrFE-CFE) / P(VDF-TrFE-CTFE) triboelectric dielectric material with a thickness of approximately 8 μm, a dielectric constant of 52 (1 kHz), and a leakage current density of 6 × 10⁻⁶. -7 A cm -2 (100MV m -1 ).

[0159] By using a friction medium material as the friction layer in a vertical contact-separation mode TENG, combined with charge excitation technology, a surface charge density of 3.8 mC / m² was achieved. -2 .

[0160] The results show that the triboelectric medium material of the present invention has a high dielectric constant and a low leakage current, and the obtained triboelectric nanogenerator has an excellent surface charge density. When the preferred embodiment is adopted, the surface charge density of the triboelectric nanogenerator is even better. In Example 5, the triboelectric medium material, under the synergistic effect of the filler and polymer, results in an even better surface charge density for the triboelectric nanogenerator.

[0161] Figure 2 and Figure 5 The graphs show the dielectric constants of the friction medium materials in Example 1 and Comparative Example 1 at different frequencies, respectively, illustrating that the addition of BTO particles in Example 1 gives the friction medium material a relatively high dielectric constant.

[0162] Figure 3 and Figure 6 The surface charge density diagrams (operating frequency 1.4 Hz) of the friction medium materials of Example 1 and Comparative Example 1 as the friction layer illustrate that, under the action of the friction medium material of the present invention, the surface charge density of the generator can reach 6 mC / m². -2 The control group (component 1) only reached 3.5 mC m. -2 .

[0163] Figure 4 The image shows a cross-sectional SEM image of the P(VDF-TrFE-CFE) friction medium material in Comparative Example 1. It can be seen that the P(VDF-TrFE-CFE) friction layer has porosity defects, which leads to a large leakage current (9 × 10⁻⁶) in this friction medium material. -7 A cm -2 100MV m -1 This results in TENG achieving only 3.5mC m -2 Surface charge density.

[0164] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A friction medium material, characterized in that, The friction medium material is a film material comprising a continuous phase of at least one polymer and at least one filler dispersed in the continuous phase; In the friction medium material, the filler has a volume percentage of 0.1-2 vol%. The packing material is a combination of one-dimensional and two-dimensional packing materials; The volume percentage of the one-dimensional packing relative to the total volume of the one-dimensional and two-dimensional packings is 1-70 vol%. The one-dimensional filler is at least one of lead zirconate titanate fiber, calcium copper titanate fiber, barium titanate fiber, and strontium titanate fiber. The two-dimensional filler is at least one of strontium titanate nanosheets, barium titanate nanosheets, and lead zirconate titanate nanosheets; The polymer is selected from a combination of poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) and poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene); The mass ratio of poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) to poly(vinylidene fluoride-trifluoroethylene-trifluorochloroethylene) is 1:0.1-9; the weight average molecular weight of the polymer is 450,000-550,000 g / mol.

2. The friction medium material according to claim 1, wherein, The average length of the one-dimensional packing is 1-7 μm; the average diameter of the one-dimensional packing is 50-700 nm.

3. The friction medium material according to claim 2, wherein, The average length of the one-dimensional packing is 1-5 μm; the average diameter of the one-dimensional packing is 50-500 nm.

4. The friction medium material according to claim 3, wherein, The average length of the one-dimensional packing is 2-3 μm; the average diameter of the one-dimensional packing is 60-200 nm.

5. The friction medium material according to claim 1, wherein, The average length of the two-dimensional packing is 1-7 μm; the average thickness of the two-dimensional packing is 1-700 nm.

6. The friction medium material according to claim 5, wherein, The average length of the two-dimensional filler is 1-5 μm; the average thickness of the two-dimensional filler is 1-500 nm.

7. The friction medium material according to claim 6, wherein, The average length of the two-dimensional filler is 2-3 μm; the average thickness of the two-dimensional filler is 50-200 nm.

8. The friction medium material according to any one of claims 1-7, wherein, The polymer has a dielectric constant ≥10 at 1 kHz and a thickness of 8±2 μm.

9. The friction medium material according to claim 8, wherein, When the thickness of the friction medium material is 8±2 μm, the dielectric constant at 1 kHz is ≥45.

10. The friction medium material according to claim 9, wherein, When the thickness of the friction medium material is 8±2 μm, the dielectric constant is ≥50 at 1 kHz.

11. The friction medium material according to claim 10, wherein, When the thickness of the friction medium material is 8±2 μm, the dielectric constant at 1 kHz is ≥55.

12. The friction medium material according to any one of claims 1-7, wherein, The friction medium material has a leakage current density ≤ 1 x 10 -1 A cm -5 at an electric field strength of 100 MV m -2 -1.

13. The friction medium material according to claim 12, wherein, The friction medium material is used in an electric field with a strength of 100 MV m. -1 The leakage current density is ≤1×10 -6 A cm -2 .

14. The friction medium material according to claim 13, wherein, The friction medium material is subjected to an electric field strength of 100 mV m. -1 The leakage current density is ≤1×10 -7 A cm -2 .

15. The friction medium material according to any one of claims 1-7, wherein, The thickness of the friction medium material is 1-100 μm.

16. The friction medium material according to claim 15, wherein, The thickness of the friction medium material is 1-50 μm.

17. The friction medium material according to claim 16, wherein, The thickness of the friction medium material is 5-10 μm.

18. A method for preparing a friction medium material according to any one of claims 1-17, characterized in that, Includes the following steps: (1) Mix at least one polymer, at least one filler and a solvent to obtain a mixed solution; (2) The mixed solution is coated on the substrate, dried, and peeled off to obtain the friction medium material; The amount of filler added is 0.1-2 vol of the total volume of the polymer and filler.

19. The preparation method according to claim 18, wherein, The ratio of the total mass of the filler and polymer to the volume of the solvent is 0.05-0.2 g / mL.

20. The preparation method according to claim 19, wherein, The ratio of the total mass of the filler and polymer to the volume of the solvent is 0.07-0.18 g / mL.

21. The preparation method according to claim 20, wherein, The ratio of the total mass of the filler and polymer to the volume of the solvent is 0.1-0.16 g / mL.

22. The preparation method according to claim 18, wherein, The solvent is a polar solvent.

23. The preparation method according to claim 22, wherein, The solvent is selected from at least one of N,N-dimethylformamide, acetone, and N-methyl-2-pyrrolidone.

24. The preparation method according to claim 18, wherein, The substrate is selected from glass, silicon wafer, aluminum foil, copper foil or PET film.

25. The preparation method according to claim 24, wherein, The glass is selected from insulating glass or conductive glass.

26. The preparation method according to claim 25, wherein, The conductive glass is ITO glass or FTO glass.

27. The preparation method according to claim 18, wherein the drying temperature is 40-80℃ and the drying time is 5-24 h.

28. The preparation method according to claim 18, wherein, The coating method includes: The mixed solution is cast onto a substrate; Alternatively, the mixed solution can be spin-coated onto the substrate.

29. The preparation method according to claim 28, wherein, The height of the scraper used for casting is 100-1000 μm.

30. The preparation method according to claim 28, wherein, The spin coating speed is 300-3000 rpm, and the time is 10-120 s.

31. The application of the triboelectric material according to any one of claims 1-17 in a triboelectric nanogenerator.

32. A triboelectric nanogenerator, wherein the generator comprises the triboelectric medium material according to any one of claims 1-17.

33. The triboelectric nanogenerator according to claim 32, wherein the surface charge density of the triboelectric nanogenerator is greater than or equal to 4 mC / m at a frequency of 1.4 Hz. -2 .

34. The triboelectric nanogenerator according to claim 33, wherein the surface charge density of the triboelectric nanogenerator is greater than or equal to 5 mC / m at a frequency of 1.4 Hz. -2 .

35. The triboelectric nanogenerator according to claim 34, wherein the surface charge density of the triboelectric nanogenerator is greater than or equal to 6 mC / m at a frequency of 1.4 Hz. -2 .

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