A BTO@rGO hybrid filler and its application in a sliding triboelectric nanogenerator

Abstract

This invention provides a BTO@rGO hybrid filler and its application in a sliding triboelectric nanogenerator, belonging to the field of micro-generator technology. The invention also provides a method for preparing the BTO@rGO hybrid filler, including using a chemical synthesis method to connect BTO and rGO, two fillers with different functions, into a structurally stable hybrid through covalent bonding between amino and carboxyl groups. Furthermore, the invention describes using the hybrid filler to prepare a reinforced polyimide composite film, and applying the composite film in a sliding triboelectric nanogenerator. The BTO@rGO hybrid filler-reinforced polyimide composite film prepared by this invention possesses both excellent electrostatic properties and wear resistance, and can be widely used in STENG's tribological layer materials, having significant engineering application value in fields such as self-powered sensors and wearable electronic devices.

Description

Technical Field

[0001] This invention belongs to the field of micro generator technology, and specifically relates to a BTO@rGO hybrid filler and its application in a sliding triboelectric nanogenerator. Background Technology

[0002] Triboelectric nanogenerators (STENGs), as a novel energy harvesting technology, can convert mechanical energy, which is widely present in the environment, into electrical energy, and have broad application prospects in fields such as self-powered sensors and wearable electronic devices. The triboelectric layer material is the core component of STENGs, and its electrical properties and wear resistance directly determine the device's output power, operational stability, and lifespan.

[0003] Polyimide is widely used as the negative friction layer material for STENGs due to its excellent heat resistance, mechanical properties, and chemical stability. However, pure polyimide has the following prominent problems in practical applications: 1) Insufficient charging performance: the low surface charge density of pure polyimide limits the charging output of STENGs; 2) Severe wear problem: pure polyimide experiences severe wear during long-term friction, reducing the effective contact area and increasing charge neutralization caused by the transfer film, further reducing the charging output.

[0004] In existing technologies, fillers (such as barium titanate, carbon nanotubes, and reduced graphene oxide) are typically added to the polyimide matrix to improve its electrostatic or wear resistance properties. However, current methods often focus on optimizing a single property, either solely on improving electrostatic or wear resistance, lacking designs that can simultaneously achieve synergistic optimization of both electrostatic and wear-reduction properties. Furthermore, when multiple fillers are simply mixed physically, there is a lack of effective bonding between them, leading to phase separation and hindering the realization of synergistic effects.

[0005] To improve the bonding of various fillers, existing research often employs covalent bonding to construct hybrid fillers. Among these, barium titanate@carbon nanotubes (BTO@CNT) has attracted some attention as a typical inorganic-carbon-based hybrid filler. Previous studies have confirmed that BTO@CNT can synergistically leverage the high dielectric properties of BTO and the conductivity of CNT to improve the dielectric properties of the polymer matrix. However, current research on BTO@CNT mainly focuses on dielectric performance characterization and has not yet been practically applied to the friction layer of triboelectric nanogenerators (STENGs). Although it is theoretically possible that it can enhance charging performance, existing work lacks a systematic study of the charging and wear behavior in STENGs. CNTs, being one-dimensional tubular structures, are prone to stress concentration under cyclic sliding, leading to fracture or detachment, which may affect wear reduction and thus reduce the improvement in charging performance. In contrast, reduced graphene oxide (rGO), with its two-dimensional sheet structure, is superior to CNT in constructing robust hybrid interfaces and dispersing contact stress. By covalently connecting BTO and rGO, it is easier to simultaneously optimize charging and wear resistance. However, there are currently no reports on the application of this covalently bonded BTO@rGO hybrid filler in STENG friction layers.

[0006] Therefore, developing a novel hybrid filler that enhances both charge generation and wear resistance through covalent bonding and applying it to STENGs is of significant scientific and engineering value for the practical application of high-charge, long-life STENGs. Summary of the Invention

[0007] This invention provides a barium titanate-reduced graphene oxide (BTO@rGO) hybrid filler, formed by covalent bonding between amino-modified barium titanate (BTO) and carboxylated reduced graphene oxide (rGO). The hybrid filler is uniformly dispersed in a polyimide matrix for use in STENG friction layer materials. Simultaneously, a barium titanate-carbon nanotube (BTO@CNT) hybrid system is used as a comparative material to verify the performance advantages of this invention.

[0008] To achieve the above objectives, the present invention provides a method for preparing BTO@rGO hybrid filler, comprising the following steps:

[0009] Preparation of S1, barium titanate aminoide (BTO)

[0010] S11. Disperse BTO in an aqueous solution of hydrogen peroxide, ultrasonically disperse, and then heat continuously to evaporate the water. Dry the resulting particles to obtain hydroxylated BTO.

[0011] S12. Hydroxylated BTO and 3-aminopropyltriethoxysilane are thoroughly stirred and ultrasonically mixed in ethanol, then heated and stirred until the solution evaporates. The resulting particles are dried and ground to obtain aminolated BTO.

[0012] Preferably, in S11, the mass ratio of BTO to hydrogen peroxide is 1:10, the ultrasonic dispersion time is 1~3h, and the heating and evaporation temperature is 150~180℃.

[0013] Preferably, in S12, the mass ratio of hydroxylated BTO to 3-aminopropyltriethoxysilane is 1:3, the ultrasonic mixing time is 1~2h, and the heating and stirring temperature is 200~250℃.

[0014] Preparation of S2, BTO@rGO hybrid filler

[0015] S21. Carboxylated reduced graphene oxide (rGO) is prepared by concentrated sulfuric acid oxidation or obtained through procurement;

[0016] S22. The aminoated BTO prepared in S1 and the carboxylated rGO prepared in S21 are dispersed in an aqueous ethanol solution, ultrasonically treated, heated and stirred until the solvent evaporates, and then dried and ground to obtain the BTO@rGO hybrid filler.

[0017] Preferably, in S22, the mass ratio of the aminoated BTO to the carboxylated rGO is (0.5~15):1, the ultrasonic stirring time is 1~3h, and the heating and evaporation temperature is 150~180℃.

[0018] The present invention also provides the application of the BTO@rGO hybrid filler in a sliding triboelectric nanogenerator, including using the BTO@rGO hybrid filler to prepare a reinforced polyimide composite film, and then using the composite film as a negative friction layer material for the sliding triboelectric nanogenerator.

[0019] Preferably, the BTO@rGO hybrid filler-reinforced polyimide composite film is prepared by the following steps:

[0020] J1. Preparation of suspension

[0021] The BTO@rGO hybrid filler prepared in S2 was dispersed in anhydrous ethanol, and then added to a polyamic acid solution and mixed evenly to obtain a suspension.

[0022] Preferably, the mass ratio of the BTO@rGO hybrid filler to polyamic acid is 1:180, the amount of anhydrous ethanol is 3-5 mL, and the mixing time is 1-2 h.

[0023] J2, Spin Coating

[0024] The silicon substrate is placed on the rotating platform of the spin coater, and the suspension prepared by J1 is poured onto the center of the silicon substrate for spin coating, so that the suspension is evenly covered on the surface of the silicon substrate.

[0025] Preferably, the spin coating parameters are as follows: spin coating at 100 rpm for 90 s, spin coating at 150 rpm for 100 s, and spin coating at 200 rpm for 120 s.

[0026] J3, Gradient Curing

[0027] The spin-coated silicon substrate is placed on a heating stage and a gradient temperature curing process is used to fully thermally imidize the polyamic acid to form a stable polyimide cross-linked network structure.

[0028] Preferably, the curing temperature and time parameters are as follows: curing at 50°C for 30 min, curing at 80°C for 25 min, curing at 125°C for 25 min, curing at 160°C for 30 min, curing at 180°C for 20 min, curing at 200°C for 20 min, curing at 220°C for 20 min, and curing at 250°C for 20 min.

[0029] J4, Remove film

[0030] After curing, allow the film to cool naturally to room temperature. Use a tool to cut open the edges of the film to release internal stress, and slowly peel off the film to obtain a BTO@rGO hybrid filler-reinforced polyimide composite film.

[0031] This invention utilizes a chemical synthesis method to link two fillers with different functions, BTO and rGO, into a structurally stable hybrid, BTO@rGO, through covalent bonding between amino and carboxyl groups. This hybrid filler simultaneously improves both electrogenic properties and wear resistance through the following synergistic mechanism:

[0032] (1) Mechanism for enhanced charging performance: In the BTO@rGO hybrid, the high dielectric constant of BTO enhances the interfacial polarization effect, effectively increasing the surface charge density. The oxygen-containing functional groups and structural defects of rGO provide sufficient active sites for electron capture, and its sheet-like structure increases the exposure rate of active sites. Combined with the uniform loading structure of BTO particles on the rGO sheets, site shielding caused by particle agglomeration is further avoided, maximizing charge capture and adsorption. At the same time, the excellent conductivity of rGO allows it to exist as a microcapacitor, significantly improving the charge storage capacity of the film. In addition, the introduction of rGO reduces wear and the resulting transfer film, thereby reducing the charge neutralization phenomenon caused by the transfer film, weakening the decay of charging performance, and reducing surface wear damage, maintaining a good charge generation interface, thus achieving a significant improvement in charging performance.

[0033] In contrast, in the BTO@CNT hybrid, the tubular morphology of CNTs results in a relatively weak exposure rate of surface defects and an effective binding force for charges. Furthermore, their extremely large aspect ratio makes them prone to tangling and forming conductive pathways that lead to charge dissipation and hinder the improvement of charging performance.

[0034] (2) Mechanism for improving wear resistance: The presence of hard BTO particles in the BTO@rGO hybrid can effectively bear the friction load and inhibit micro-cutting and plastic deformation of the matrix. The flake-like rGO exposed on the surface is easy to spread and form a lubrication transfer film, which effectively reduces wear. At the same time, the hybrid uniformly distributed in the polyimide can block the crack propagation path, reduce the generation of wear debris, and reduce material wear.

[0035] In contrast, the tubular structure of CNTs in BTO@CNT hybrids has a weaker bond with the polymer, making them prone to breakage or detachment during friction. This weakens the material's wear resistance and may form abrasive particles that participate in the wear process, further reducing wear resistance.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. Stable Filler Structure: Through the covalent bonding of amino and carboxyl groups, spherical BTO and plate-like rGO form a stable chemical bond, constructing a structurally stable hybrid filler. This method effectively avoids defects such as phase separation and agglomeration that easily occur in traditional physical mixing systems, ensuring uniform dispersion of each functional component within the composite material and achieving synergistic effects. Compared to BTO@CNT hybrid fillers, tubular CNTs have a smaller specific surface area, weaker compatibility with spherical BTO particles, and relatively insufficient overall structural stability.

[0038] 2. Synergistic Improvement of Electrostatics and Wear Resistance: Under the same test conditions, the introduction of BTO@rGO hybrid filler significantly improved the electrostatics and wear resistance of STENG. The open-circuit voltage of the BTO@rGO hybrid filler reached 34.61V, which was 124.30% and 40.98% higher than that of the unfilled and BTO@CNT reinforced cases, respectively. The wear mass was only 0.266mg, which was 53.66% and 18.65% lower than that of the unfilled and BTO@CNT reinforced cases, respectively.

[0039] 3. Broad application prospects: The BTO@rGO hybrid filler-reinforced polyimide composite film prepared by this invention has both excellent electrostatic properties and wear resistance, and can be widely used in STENG's friction layer materials. It has important engineering application value in fields such as self-powered sensors and wearable electronic devices. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 The diagram shows the hybridization reaction process of amino-modified BTO and carboxylated rGO in the preparation of the BTO@rGO hybrid in Example 1.

[0042] Figure 2 (a) shows the SEM images of the BTO@rGO hybrids prepared in Examples 1-2. Figure 2 (b) is a SEM image of the BTO@CNT hybrid prepared in Comparative Example 2;

[0043] Figure 3 This is a flowchart illustrating the preparation process of the BTO@rGO-doped polyimide composite film in Example 1.

[0044] Figure 4 The figures show the performance test results of STENG after filling-free, BTO@rGO filling and BTO@CNT doping, where (a) is the stable open circuit voltage and (b) is the wear quality. Detailed Implementation

[0045] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0046] The carboxylated rGO in Example 1 was purchased from KERI Nano (Guangdong) Co., Ltd.; the carboxylated CNT in Comparative Example 2 was purchased from Shenzhen Guoheng Qihang Technology Co., Ltd.

[0047] Example 1

[0048] 1. Preparation of BTO@rGO hybrid packing material

[0049] (1) Preparation of barium titanate amide (BTO)

[0050] 15g of BTO was dispersed in 450mL of 30wt% hydrogen peroxide aqueous solution, ultrasonically treated for 2h, and then continuously stirred and heated on a heating platform at 160℃. After the water evaporated, the resulting particles were placed in a drying oven and dried at 80℃ for 12h to obtain hydroxylated BTO.

[0051] Hydroxylated BTO was thoroughly stirred and ultrasonically mixed with 48 mL of 3-aminopropyltriethoxysilane in ethanol for 60 min. Then, the mixture was heated and stirred at 220 °C until the solution evaporated. The resulting particles were dried at 80 °C for 24 h and then ground in a mortar for 30 min to refine them, thus obtaining aminolated BTO.

[0052] (2) Preparation of BTO@rGO hybrid

[0053] Aminated BTO and carboxylated rGO were dispersed in ethanol at a certain mass ratio. After ultrasonic stirring for 120 min, the mixture was heated and stirred at 160 °C until the solution evaporated, causing the amino and carboxyl groups to undergo a condensation reaction to form covalent bonds. The hybridization reaction process of the above-mentioned aminated BTO and carboxylated rGO is as follows: Figure 1 As shown.

[0054] The obtained particles were dried at 80℃ for 12 h and then ground to obtain the BTO@rGO hybrid. The SEM image of the BTO@rGO hybrid when the mass ratio of BTO to rGO was 1:1 is shown below. Figure 2 As shown in (a), rGO exhibits a typical two-dimensional wrinkled sheet structure, with BTO nanoparticles uniformly attached to the surface of the rGO sheets without significant agglomeration, achieving monodisperse loading. Therefore, it can further avoid site shielding caused by particle agglomeration and maximize charge capture and adsorption.

[0055] 2. Preparation of BTO@rGO hybrid filler-reinforced polyimide composite films

[0056] Hybrid filler-reinforced polyimide composite films were prepared using a solution blending method combined with a gradient curing process. The preparation process is as follows: Figure 3 As shown.

[0057] (1) Weighing

[0058] Weigh 15g of polyamic acid solution into a disposable experimental cup, and weigh a certain mass of hybrid filler. The mass ratio of BTO@rGO hybrid filler to polyamic acid is 1:180.

[0059] (2) Preparation of suspension

[0060] The weighed filler was mixed with 3 mL of anhydrous ethanol and stirred until homogeneous. The mixture was then poured into a polyamic acid solution and stirred for 60 min. Subsequently, the mixture was treated under a pressure of -0.1 MPa for more than 60 min to remove air bubbles, resulting in a homogeneous suspension.

[0061] (3) Spin coating

[0062] The cleaned and smooth silicon substrate is placed on the rotating platform of the spin coater and fixed by vacuum adsorption. The suspension is poured into the center of the silicon substrate, and the spin coating parameters are set. Spin coating is performed sequentially at the following times and speeds: 100 rpm / 90s, 150 rpm / 100s, and 200 rpm / 120s. The spin coater is then started to ensure that the suspension is evenly covered on the surface of the silicon substrate.

[0063] (4) Gradient curing

[0064] The spin-coated silicon substrate was placed on a heating stage and cured using a gradient temperature curing process at the following times and temperatures in sequence: 50℃ / 30min, 80℃ / 25min, 125℃ / 25min, 160℃ / 30min, 180℃ / 20min, 200℃ / 20min, 220℃ / 20min, and 250℃ / 20min, to fully thermally imidize the polyamic acid and form a stable polyimide crosslinked network structure.

[0065] (5) Peel off the film

[0066] After curing, allow the film to cool naturally to room temperature. Use a tool to cut open the edges of the film to release internal stress, and slowly peel off the film to obtain a BTO@rGO hybrid filler-reinforced polyimide composite film.

[0067] Comparative Example 1

[0068] Preparation of filler-free polyimide films

[0069] Except for the absence of filler, the preparation process of the fillerless polyimide film is the same as that of the BTO@rGO hybrid filler-reinforced polyimide composite film in Example 1.

[0070] Comparative Example 2

[0071] 1. Preparation of BTO@CNT hybrid packing material

[0072] Except for replacing carboxylated rGO with carboxylated CNT, the preparation process of BTO@CNT hybrid filler is the same as that of BTO@rGO hybrid filler in Example 1.

[0073] Figure 2 (b) is a SEM image of the BTO@CNT hybrid, in which the mass ratio of BTO to CNT is 1:1. It can be seen that although the BTO nanoparticles are attached to the CNT surface, the composite of the two materials is achieved. However, the disordered entanglement of the CNT network not only causes uneven dispersion of the filler, but also easily forms continuous conductive paths, hindering the improvement of the charging performance.

[0074] 2. Preparation of BTO@CNT reinforced polyimide composite films

[0075] Except for replacing the BTO@rGO hybrid filler with the BTO@CNT hybrid filler, the preparation process of the BTO@CNT reinforced polyimide composite film is the same as that of the BTO@rGO reinforced polyimide composite film in Example 1.

[0076] Test case

[0077] Applications in triboelectric nanogenerators

[0078] The BTO@rGO hybrid filler-reinforced polyimide composite film prepared in the above embodiments was used as a negative friction layer material, paired with electrodes, and assembled into a STENG. Simultaneous charging and wear tests were conducted, with a normal load of 15 N, a sliding limit distance of 12.5 mm, a reciprocating sliding frequency of 6.67 Hz, and a continuous sliding duration of 60 min.

[0079] Table 1 shows the open-circuit voltage and wear mass of STENG reinforced with BTO@rGO hybrid filler under different BTO to rGO mass ratios. It can be seen that the open-circuit voltage first increases and then decreases with increasing BTO to rGO mass ratio. Examples 1-4 exhibit the highest open-circuit voltage (34.61V) at a BTO to rGO mass ratio of 10:1, while the wear mass is also relatively low at only 0.266mg.

[0080] Combining product morphology and theoretical studies, it is evident that when the mass ratio of BTO to rGO is small, the low BTO content leads to a weaker interfacial polarization effect. Although rGO provides sufficient electron-trapping active sites, the charge output remains low. As the mass ratio increases to an appropriate value (e.g., 10:1), BTO is uniformly dispersed on the surface of the rGO sheets, significantly enhancing interfacial polarization, while rGO retains effective electron-trapping capabilities. Furthermore, the uniform and stable filler structure increases material hardness, and the smooth transfer film reduces wear, resulting in a lower transfer film coverage. Consequently, charge neutralization is weakened, and the charge output reaches its maximum. When the mass ratio further increases, excessive BTO agglomerates and coats rGO, obscuring its electron-trapping active sites. Simultaneously, BTO is easily worn away during friction, forming abrasive particles, exacerbating wear. This leads to an increase in transfer film coverage, resulting in significant charge neutralization and a decrease in charge output.

[0081] Table 1. Open-circuit voltage and wear mass at different BTO to rGO mass ratios

[0082]

[0083] The BTO@rGO films from Examples 1-4 were compared with the unfilled polyimide film prepared in Comparative Example 1 and the BTO@CNT hybrid filler-reinforced polyimide composite film prepared in Comparative Example 2 as control samples for performance comparison testing. In Comparative Example 2, the mass ratio of BTO to CNT in the hybrid filler was 10:1, consistent with the mass ratio of BTO to rGO in Examples 1-4. The results show that the introduction of BTO@rGO can significantly improve the electrostatic and wear resistance properties of STENG, such as... Figure 4 As shown.

[0084] Specifically, Figure 4(a) shows the open-circuit voltage test results. It can be seen that the open-circuit voltage of the unfilled film in Comparative Example 1 is 15.43V. After introducing BTO@rGO hybrid filler, the open-circuit voltage increases to 34.61V, which is 124.30% higher than the unfilled system. After introducing BTO@CNT hybrid filler, the open-circuit voltage is 24.55V. Although it is also higher than the unfilled sample, the voltage increase is much smaller than that of the BTO@rGO system, proving that BTO@rGO has a better optimization effect on triboelectric output performance.

[0085] Figure 4 (b) shows the wear mass test results. It can be seen that the wear mass of the unfilled film is 0.574 mg. After introducing the BTO@rGO hybrid filler, the wear mass decreased to 0.266 mg, a reduction of 53.66% compared to the unfilled system. While the wear mass of the BTO@CNT hybrid filler is 0.327 mg, which is also higher than the unfilled sample, the reduction in wear is less significant than that of the BTO@rGO system, demonstrating that BTO@rGO has a superior effect on improving wear resistance.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A BTO@rGO hybrid packing material, characterized in that, It is formed by covalent bonding between barium titanate aminated (BTO) and carboxylated reduced graphene oxide (rGO).

2. A method for preparing a BTO@rGO hybrid filler, characterized in that, Includes the following steps: Preparation of S1, barium titanate aminoide (BTO) S11. Disperse BTO in an aqueous solution of hydrogen peroxide, ultrasonically disperse, and then heat continuously to evaporate the water. Dry the resulting particles to obtain hydroxylated BTO. S12. Hydroxylated BTO and 3-aminopropyltriethoxysilane were thoroughly stirred and ultrasonically mixed in ethanol, then heated and stirred until the solution evaporated. The resulting particles were dried and ground to obtain aminolated BTO. Preparation of S2, BTO@rGO hybrid filler S21. Carboxylated reduced graphene oxide (rGO) is prepared by concentrated sulfuric acid oxidation or obtained through procurement; S22. The aminoated BTO prepared in S1 and the carboxylated rGO prepared in S21 are dispersed in an aqueous ethanol solution, ultrasonically treated, heated and stirred until the solvent evaporates, and then dried and ground to obtain the BTO@rGO hybrid filler.

3. The method for preparing BTO@rGO hybrid filler according to claim 2, characterized in that, In S11, the mass ratio of BTO to hydrogen peroxide is 1:10, the ultrasonic dispersion time is 1~3h, and the heating and evaporation temperature is 150~180℃; And / or, in S12, the mass ratio of the hydroxylated BTO to 3-aminopropyltriethoxysilane is 1:3, the ultrasonic mixing time is 1~2h, and the heating and stirring temperature is 200~250℃.

4. The method for preparing the BTO@rGO hybrid filler according to claim 2, characterized in that, In S22, the mass ratio of amino-modified BTO to carboxylated rGO is (0.5~15):1, the ultrasonic stirring time is 1~3h, and the heating and evaporation temperature is 150~180℃.

5. The application of the BTO@rGO hybrid filler according to claim 1 or the BTO@rGO hybrid filler prepared by the method according to any one of claims 2 to 4 in a sliding triboelectric nanogenerator.

6. The application according to claim 5, characterized in that, This includes using the BTO@rGO hybrid filler to prepare a reinforced polyimide composite film, and then using the composite film as a negative friction layer material for a sliding triboelectric nanogenerator.

7. The application according to claim 6, characterized in that, The preparation method of BTO@rGO hybrid filler reinforced polyimide composite film includes the following steps: J1. Preparation of suspension: The BTO@rGO hybrid filler is dispersed in anhydrous ethanol, and then added to polyamic acid solution and mixed evenly to obtain a suspension; J2, Spin coating: Place the silicon substrate on the rotating platform of the spin coater, pour the suspension prepared in J1 onto the center of the silicon substrate for spin coating, so that the suspension evenly covers the surface of the silicon substrate. J3. Gradient curing: The spin-coated silicon substrate is placed on a heating stage and a gradient temperature curing process is used to fully thermally imidize the polyamic acid to form a polyimide cross-linked network structure. J4. Film Removal: After curing, allow the film to cool naturally to room temperature. Use a tool to cut open the edges of the film to release internal stress and peel it off to obtain the BTO@rGO hybrid filler reinforced polyimide composite film.

8. The application according to claim 7, characterized in that, In J1, the mass ratio of the BTO@rGO hybrid filler to polyamic acid is 1:180, the amount of anhydrous ethanol is 3~5mL, and the stirring time is 1~2h.

9. The application according to claim 7, characterized in that, In J2, the spin coating parameters are as follows: spin coating at 100 rpm for 90 seconds, spin coating at 150 rpm for 100 seconds, and spin coating at 200 rpm for 120 seconds.

10. The application according to claim 7, characterized in that, In J3, the curing temperature and time parameters are as follows: curing at 50℃ for 30 min, curing at 80℃ for 25 min, curing at 125℃ for 25 min, curing at 160℃ for 30 min, curing at 180℃ for 20 min, curing at 200℃ for 20 min, curing at 220℃ for 20 min, and curing at 250℃ for 20 min.

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