All-organic composite material as well as preparation method and application thereof

Abstract

The invention belongs to the field of thin film capacitors and related dielectric materials, and particularly discloses an all-organic composite material as well as a preparation method and application thereof, and the all-organic composite material comprises the following components in percentage by mass: 98.00 wt%-99.75 wt% of fluorene polyester and 0.25 wt%-2.00 wt% of hexacyanohexaazabenzophenanthrene. The preparation method comprises the following steps: respectively adding fluorene polyester and hexacyanohexaazabenzophenanthrene into an organic solvent, fully stirring and dissolving, and ultrasonically mixing to obtain a uniformly mixed solution; uniformly coating a substrate with the mixed solution, heating, carrying out vacuum annealing, and stripping to obtain the fluorene polyester / hexacyanohexaazabenzophenanthrene composite film. According to the invention, the charge-discharge efficiency and discharge energy density of the polymer under high temperature and high electric field are improved, the technical problems of high leakage loss and low charge-discharge efficiency of the existing polymer film are solved, and large-scale industrial production is easy to realize.

Description

Technical Field

[0001] This invention belongs to the field of thin-film capacitors and related dielectric materials, and more specifically, relates to an all-organic composite material, its preparation method and application. Background Technology

[0002] Polymer dielectric materials are key materials for film capacitors. However, fields such as hybrid electric vehicles, aerospace, and underground oil and gas exploration place higher demands on the high-temperature resistance of film capacitors. For example, the ambient temperature of capacitors in hybrid electric vehicle inverters is 140–150°C. o C, underground oil and gas exploration equipment even reaches 200 o Temperatures above 30°C are therefore urgently needed for dielectric materials with high-temperature capacitive energy storage capabilities.

[0003] Currently, commercially available biaxially oriented polypropylene (BOPP) films, which are polymer dielectric materials, can only achieve a dielectric strength of 10⁵. o Operating below C, it is difficult to meet high-temperature requirements. It has a high glass transition temperature ( T g Fluorene polymers, due to their excellent thermal stability, have become a hot topic in current research on high-temperature polymer dielectric materials. Among them, fluorene polyester (FPE) stands out for its high thermal stability of up to 320°C. o C T g The stable low dielectric loss at high temperatures has attracted widespread attention in engineering applications such as electrical insulation and energy storage. However, under the combined effects of high temperature and strong electric field, the conjugated structure in FPE molecules can cause a significant increase in leakage current, resulting in a sharp drop in charge and discharge efficiency, thus limiting its application potential in high-temperature dielectric energy storage.

[0004] Polymer blending is a current approach to modifying FPE, with the FPE / polyarylether urea (PEEU) system being a representative example (patent CN120157928A). Its core modification mechanism is clear: the flexible segments of PEEU are inserted into the conjugated backbone of FPE, forcibly distorting the arrangement of FPE molecular chains through steric hindrance, thus disrupting the "conjugated channels" upon which charge migration depends—essentially a passive, "blocking" control strategy. This approach has two inherent drawbacks: First, it only slows down the charge movement rate, completely failing to change the core property of FPE—its tendency to easily generate free charges under high temperatures and electric fields due to its conjugated structure. This causes the captured free charges to accumulate continuously at the FPE / PEEU blend interface under high-temperature conditions, leading to a sharp drop in high-temperature cyclic charge-discharge efficiency and interfacial polarization relaxation, making stability difficult to guarantee. Secondly, there is an irreconcilable contradiction between improving the energy storage performance of high-temperature capacitors and the stability of the system: the modification effect of this blend system strongly depends on the high addition amount of PEEU (up to 30 wt%), while the flexible chain of PEEU and the rigid structure of FPE are inherently in conflict. The high addition amount will significantly weaken the high-temperature mechanical properties of FPE and cannot meet the load-bearing requirements of high-temperature equipment.

[0005] By incorporating wide bandwidth ( E g Inorganic nanoparticles or high electron affinity E a Molecular semiconductors can suppress the conductivity of materials, thereby improving dielectric energy storage performance at high temperatures. However, wide... E g Inorganic nanoparticles such as BN and Al2O3 E a The charge is very small and cannot be effectively captured. At high temperatures, the charge easily bypasses the filler, and voids and cracks easily form at the inorganic-organic interface, further creating "conductive channels," ultimately leading to increased leakage current and decreased charge-discharge efficiency. This method is essentially no different from polymer blending; both involve "passive barrier" rather than "active charge handling." E a Molecular semiconductors such as 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetra(4-hexylphenyl)-dithiopheno[2,3-d:2',3'-d']-s-indan[1,2-b:5,6-b']dithiophene (ITIC), fullerene phenyl C71-butyrate methyl ester, propyl C61-butyrate octyl ester, 6,6-phenyl-C61-butyrate methyl ester (PCBM), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanodimethyl-p-benzoquinone (F4-TCNQ), 4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA), etc. E gIf the band gap is too small, the trapped charge at high temperatures is prone to jump across the band gap, migrate within the filler, or even transfer to the polymer matrix, resulting in a decrease in breakdown strength and unsatisfactory high-temperature energy storage performance.

[0006] Therefore, the development of high-quality products is essential. E a Hekuan E g Furthermore, the development of novel functional fillers with excellent thermal stability and simple and environmentally friendly preparation processes to improve the capacitive energy storage performance of composite systems under high temperature and high electric field conditions has become a pressing technical problem to be solved in this field. Summary of the Invention

[0007] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides an all-organic composite material, its preparation method and application, the purpose of which is to improve the high-temperature dielectric energy storage performance of composite dielectric energy storage materials.

[0008] To achieve the above objectives, according to a first aspect of the present invention, an all-organic composite material is provided, comprising, by mass fraction: 98.00 wt% to 99.75 wt% fluorene polyester and 0.25 wt% to 2.00 wt% hexacyanohexaazabenzophenanthrene.

[0009] As a further preferred embodiment, the all-organic composite material comprises, by mass fraction: 99.00 wt% to 99.75 wt% fluorene polyester and 0.25 wt% to 1.00 wt% hexacyanohexaazabenzophenanthrene.

[0010] As a further preferred embodiment, the fluorene polyester has an average molecular weight of 5,000 to 20,000.

[0011] According to a second aspect of the present invention, a method for preparing the above-mentioned all-organic composite material is provided, comprising the following steps: (1) Fluorene polyester and hexacyanohexaazabenzophenanthrene were added to an organic solvent by mass fraction and stirred to dissolve, and then mixed to obtain a mixed solution; (2) The mixed solution is uniformly coated on the substrate and then dried. The resulting composite film is then vacuum annealed. (3) The composite film after vacuum annealing is peeled off from the substrate and then dried to obtain fluorene polyester / hexacyanohexaazabenzophenanthrene all-organic composite material.

[0012] As a further preferred embodiment, the drying in step (2) specifically involves: first drying at 30-50°C. o Preheat at C for 20–60 minutes, then at 60–80 degrees Celsius. o Dry at C for 8–12 h to remove solvent, then dry at 110–125 °C. o C and 135~155o Dry at C for 1-2 hours, and finally dry at 180-200°C. o Dry at C for 12–24 h; vacuum annealing temperature is 120–200 °C. o C, the time is 12 to 24 hours.

[0013] As a further preferred embodiment, in step (1), the ratio of the sum of the masses of fluorene polyester and hexacyanohexaazabenzophenanthrene to the volume of the organic solvent is 20–40 mg·mL. -1 .

[0014] As a further preferred embodiment, the temperature during stirring and dissolving in step (1) is 35–60 °C. o C, stirring time 8–12 h; the mixed solution is obtained by ultrasonic mixing at a temperature of 30–50 °C. o C, the ultrasound time is 30-60 min, and the ultrasound power is 100-350 W.

[0015] As a further preferred embodiment, the organic solvent in step (1) is dimethylformamide, One or a combination of two of methylpyrrolidones.

[0016] As a further preferred embodiment, the peeling method in step (3) is as follows: the composite film after vacuum annealing is immersed in deionized water to peel the composite film off from the substrate, and then the composite film is taken out and dried to remove water. The drying temperature is 30-50°C. o C, time is 1 to 5 hours.

[0017] According to a third aspect of the present invention, a thin-film capacitor is provided, which uses the above-mentioned all-organic composite material as its polymer dielectric material.

[0018] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. The FPE / HAT-CN all-organic composite material of the present invention, by introducing into fluorene polyester (FPE) a composite material with high... E a Hekuan E g The hexacyanohexaazabenzophenanthrene (HAT-CN) constructs a synergistic system of "precise charge capture - stable binding - improved dielectric properties," which helps to improve the energy storage performance of high-temperature capacitors. E a HAT-CN is advantageous for constructing deep-level traps inside FPE (such as...). Figure 2 and Figure 3As shown in the figure, the high electric field suppresses conductivity loss because the local state density in the polymer is high. After electron injection, they are bound to different local state energy levels. The conductivity mainly originates from the jumping migration of electrons between local states. E a HAT-CN can form deep traps, effectively hindering the migration of electrons between local states, ultimately suppressing conductivity losses under high temperature and high electric field conditions. Simultaneously, HAT-CN exhibits wide... E g This significantly reduces the mobility of trapped charges, meaning that trapped charges cannot participate in electrical conduction, thus eliminating the risk of leakage at its source. This "active capture and stable binding" mechanism can be effectively combined with polymer blending or the addition of high-concentration polymers. E g Inorganic nanoparticles / high E a This is fundamentally different from the passive logic of "blocking without processing" small molecules. Furthermore, the large number of highly polar cyano groups on HAT-CN helps to improve the dielectric constant of the composite film.

[0019] In summary, this invention effectively improves the high-temperature dielectric energy storage performance of composite thin films, achieving the desired effect at 150°C. o C maintains a discharge energy density of ≥90% ( U 90 The value is 7.31 J·cm. -3 In 200 o C U 90 It is 5.16 J·cm -3 ; far exceeding polymer FPE (150 o C U 90 It is 1.33 J·cm -3 200 o C U 90 It is 0.98 J·cm -3 Furthermore, composite films can be applied at 200... o C@400 MV·m -1 It maintains essentially unchanged performance after 100,000 charge-discharge cycles, demonstrating excellent stability.

[0020] 2. This invention designs the mass fractions of FPE and HAT-CN in the composite material. Based on the charge trapping mechanism of HAT-CN and the characteristics of the FPE matrix, the optimal proportion of HAT-CN is determined to be 0.25–2 wt%. Specifically, HAT-CN needs to be uniformly dispersed to form a "molecular-level trap network" to achieve precise charge trapping. The effectiveness depends on the dispersion state rather than simply the amount added. When HAT-CN is below 0.25 wt%, the trap density is insufficient, and it cannot effectively trap the free charges of FPE at high temperatures, resulting in poor leakage current suppression and difficulty in meeting high-temperature energy storage requirements. Above 2 wt%, HAT-CN molecules are prone to agglomeration due to π-π stacking, which not only damages the FPE structure leading to a decrease in breakdown strength but also forms charge migration channels, increasing high-temperature dielectric loss. Within the 0.25–2 wt% range, HAT-CN can be uniformly dispersed in FPE, achieving both high-temperature dielectric loss and effective charge trapping. E a With width E g It features efficient charge capture to enhance energy storage performance, and can also enhance the high-temperature mechanical stability of FPE with a rigid nitrogen-based framework, thus achieving synergistic optimization of "charge regulation-energy storage performance-mechanical performance".

[0021] 3. This invention uses a solution casting method to prepare FPE / HAT-CN all-organic composite films. The preparation process of HAT-CN is low in toxicity, making the entire preparation process simple, environmentally friendly, efficient, and easy to industrialize. It has important application value in aerospace, oil extraction, and hybrid vehicles. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the molecular structure of FPE and HAT-CN in an embodiment of the present invention.

[0023] Figure 2 This is a diagram illustrating the mechanism of trap formation inside the polymer material in an embodiment of the present invention.

[0024] Figure 3 This is a diagram of deep traps formed inside the polymer material in an embodiment of the present invention.

[0025] Figure 4 For embodiments of the present invention, HAT-CN and other molecular semiconductors E a and E g Comparison chart.

[0026] Figure 5 This is a thermal stability diagram of HAT-CN according to an embodiment of the present invention.

[0027] Figure 6 Examples 1-4 and Comparative Examples 1-3 of the present invention were prepared at 25-200°C. oThe temperature-dependent dielectric diagram of C, where the frequency is fixed at 1000 Hz.

[0028] Figure 7 Examples 1-4 and Comparative Examples 1-3 of the present invention were prepared at 200°C. o C, dielectric spectrum with a frequency of 100 to 1 MHz.

[0029] Figure 8 Examples 1-4 and Comparative Examples 1-3 of the present invention were carried out at 150°C. o Energy storage performance diagram of C.

[0030] Figure 9 Examples 1-4 and Comparative Examples 1-3 of the present invention were prepared at 200°C. o Energy storage performance diagram of C.

[0031] Figure 10 Examples 1-4 and Comparative Examples 1-3 of the present invention were prepared at 150°C. o Weibull distribution diagram of DC breakdown field strength of C.

[0032] Figure 11 Examples 1-4 and Comparative Examples 1-3 of the present invention were prepared at 200°C. o Weibull distribution diagram of DC breakdown field strength of C.

[0033] Figure 12 For Embodiment 2 and Comparative Example 1 of the present invention, at 200 o Comparison chart of C's loop performance.

[0034] Figure 13 Examples 1-4 of the present invention and Comparative Example 1 were respectively at 150°C o C and 200 o Comparison chart of high-temperature mechanical energy storage modulus of C. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0036] An embodiment of the present invention provides an all-organic composite material comprising, by mass fraction: 98.00 wt% to 99.75 wt% fluorene polyester, and 0.25 wt% to 2.00 wt% hexacyanohexaazabenzophenanthrene.

[0037] Furthermore, the average molecular weight of the fluorene polyester is 5000-20000; preferably, the content of fluorene polyester and hexacyanohexaazabenzophenanthrene is 99.00-99.75 wt% and 0.25-1.00 wt%, respectively.

[0038] Specifically, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene (HAT-CN) is a "super electron acceptor" enhanced by the synergistic effect of the cyano group and the aza backbone, with the structural formula as follows: Figure 1 As shown, its combination with FPE forms a synergistic effect of "structural adaptation and performance complementarity". The rigid azirmonenan backbone of HAT-CN and the conjugated backbone of FPE have a natural π-π interaction matching. HAT-CN can provide local structural support for FPE through its own rigidity, and can also precisely adjust the π electron distribution through the N atoms in the backbone. While maintaining a large conjugated structure, it moderately confines the electron cloud, specifically suppressing charge conduction of the FPE conjugated backbone at high temperatures, avoiding excessive electron delocalization caused by flexible chains in materials like PCBM. E g The issue of its small size is addressed; simultaneously, the six cyano groups on its periphery form polar interactions with the FPE ester groups, strengthening interfacial bonding and generating a strong synergistic electron-withdrawing effect, significantly lowering the LUMO energy level and simultaneously modulating the HOMO energy level, ultimately achieving high... E a With width E g Positive synergy (such as) Figure 4 As shown), this provides a molecular basis for efficiently capturing free charges excited at high temperatures by FPE. Furthermore, HAT-CN exhibits excellent thermal stability (e.g., Figure 5 As shown, 250 o No significant thermal weight loss at C), temperature at which thermal decomposition occurs by 5% ( T d5 ) up to 450 o C; Furthermore, HAT-CN can be prepared by reacting cyclohexanehexanone hydrate with diaminomaleitrile, with a yield as high as 81%, and the preparation process is low in toxicity and simple. HAT-CN also possesses high... E a Hekuan E g It possesses excellent properties, is environmentally friendly in synthesis, and exhibits superior thermal stability, making it an ideal organic functional filler for polymer high-temperature capacitor energy storage. It can fully meet the energy storage performance requirements under high-temperature conditions and the needs of industrialized environmentally friendly production.

[0039] The present invention also provides a method for preparing the above-mentioned all-organic composite material, comprising the following steps: (1) Add FPE and HAT-CN to an organic solvent respectively, stir and dissolve thoroughly, and then mix ultrasonically to obtain a homogeneous mixed solution; (2) The mixed solution obtained in step (1) is uniformly coated on the substrate and then dried. The dried composite film is then vacuum annealed. (3) Peel off the composite film obtained in step (2), and then dry it to obtain the FPE / HAT-CN composite film.

[0040] Furthermore, the ratio of the sum of the masses of FPE and HAT-CN in the mixed solution to the volume of the solvent is 20–40 mg / mL. -1 .

[0041] Furthermore, the organic solvent is dimethylformamide, Any one or a combination of two of methylpyrrolidones.

[0042] Furthermore, the dissolution temperature in step (1) is 35–60 °C. o C, stirring time 8–12 h. The preferred ultrasonic temperature is 30–50 °C. o C. The ultrasonic time is 30–60 min, and the ultrasonic power is 100–350 W. In the ultrasonic process, the power and duration determine the dispersion effect of HAT-CN: if the power is too low or the time is insufficient, it is difficult to break the π-π stacking between HAT-CN molecules, which easily leads to agglomeration and subsequent uniform dispersion; if the power is too high, it will cause the FPE molecular chain to break, resulting in a decrease in the mechanical properties of the matrix.

[0043] Furthermore, the drying conditions in step (2) are: first at 30-50 °C. o Preheat at C for 20–60 minutes, then at 60–80 degrees Celsius. o Dry at C for 8–12 h to remove solvent, then dry at 110–125 °C. o C and 135~155 o Dry at C for 1-2 hours, and finally dry at 180-200°C. o Dry at 12-24°C for 12-24 hours. Transfer the dried composite film to a vacuum oven and dry at 120-200°C. o Dry at C for 12–24 h to completely remove residual solvent from the material.

[0044] Regarding temperature control for the aforementioned gradient drying: if the temperature is too low during the preheating stage, the moisture and solvent in the film cannot be released slowly, and rapid vaporization during subsequent high-temperature drying can easily lead to bubbles and cracking; if the temperature is too high, the film surface will solidify rapidly, encapsulating the internal solvent and forming micropores, thus disrupting the continuity of the charge trapping network. Temperature deviations during subsequent drying and annealing stages also affect performance; 60–80°C is recommended. o During the solvent removal stage (C), residual solvent should be removed to prevent a surge in dielectric loss during high-temperature drying; 110–125 o C / 135~155o C. Stress relief stage: This stage releases residual stress within the membrane, preventing film curling after formation; 180–200 o In the densification stage, the interfacial bonding between HAT-CN and FPE is strengthened. These process parameters and mass fraction design work synergistically to systematically avoid defects and risks in each stage, further providing reliable process assurance for the excellent comprehensive performance of the composite material.

[0045] Furthermore, the peeling conditions in step (3) involve immersing the annealed membrane in deionized water, removing the membrane, and drying it to remove water at a temperature of 30–50°C. o C, time is 1 to 5 hours.

[0046] In summary, this invention provides a packing material with excellent stability and high filler properties. E a and high E g Furthermore, a fluorene-polyester / hexacyanohexaazabenzophenanthrene all-organic composite material with excellent high-temperature dielectric energy storage performance can overcome the problems of easy agglomeration, weak charge trapping ability (inorganic nanoparticles), and high charge mobility under high electric fields (traditional high-temperature dielectric materials) present in existing FPE-based composite dielectric energy storage materials. E a Low E g The high leakage loss and low charge / discharge efficiency are caused by the shortcomings of molecular semiconductors, etc.

[0047] The following are specific examples: Example 1 Taking the preparation of a FPE / HAT-CN blend dielectric energy storage polymer film (HAT-CN doping content of 0.25 wt%) as an example, the specific preparation method is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 To prepare a polymer solution, weigh 1.0 mg of HAT-CN powder and dissolve it in 2 mL of NMP to obtain a concentration of 2 mg·mL⁻¹. -1 Small molecule solutions, both solutions at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 h, a small molecule solution (HAT-CN doping amount of 0.25 wt%) was added to the polymer solution. Stirring continued for another 2 h, followed by stirring at 100 W / 30 °C. o A homogeneous mixture was obtained by sonication at C for 30 min. An appropriate amount of the mixture was then cast onto a glass plate to form a film. The sample was first placed in a forced-air oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. oKeep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by holding the sample at 200°C for 12 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping content of 0.25 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0048] Example 2 Taking the preparation of a FPE / HAT-CN blend dielectric energy storage polymer film (HAT-CN doping amount of 0.50 wt%) as an example, the specific preparation method is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 To prepare a polymer solution, weigh 2.0 mg of HAT-CN powder and dissolve it in 4 mL of NMP to obtain a concentration of 2 mg·mL⁻¹. -1 Small molecule solutions, both solutions at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 h, a small molecule solution (HAT-CN doping amount of 0.50 wt%) was measured and added to the polymer solution. Stirring continued for another 2 h, followed by stirring at 100 W / 30 °C. o A homogeneous mixture was obtained by sonication at C for 30 min. An appropriate amount of the mixture was then cast onto a glass plate to form a film. The sample was first placed in a forced-air oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by holding the sample at 200°C for 12 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping content of 0.50 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0049] Example 3 Taking the preparation of a FPE / HAT-CN blend dielectric energy storage polymer film (HAT-CN doping content of 0.75 wt%) as an example, the specific preparation method is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 To prepare a polymer solution, weigh 3.0 mg of HAT-CN powder and dissolve it in 6 mL of NMP to prepare a 2 mg / mL solution. -1 Small molecule solutions, both solutions at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 h, a small molecule solution (HAT-CN doping amount of 0.75 wt%) was added to the polymer solution. Stirring continued for another 2 h, followed by stirring at 100 W / 30 °C. o A homogeneous mixture was obtained by sonication at C for 30 min. An appropriate amount of the mixture was then cast onto a glass plate to form a film. The sample was first placed in a forced-air oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by holding the sample at 200°C for 12 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping content of 0.75 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0050] Example 4 Taking the preparation of a FPE / HAT-CN blend dielectric energy storage polymer film (HAT-CN doping content of 1.00 wt%) as an example, the specific preparation method is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 To prepare a polymer solution, weigh 4.0 mg of HAT-CN powder and dissolve it in 8 mL of NMP to prepare a 2 mg / mL solution. -1 Small molecule solutions, both solutions at 50 o C at 300 rpm·min -1After magnetic stirring at a constant rate for 8 h, a small molecule solution (HAT-CN doping amount of 1.00 wt%) was measured and added to the polymer solution. Stirring continued for another 2 h, followed by stirring at 100 W / 30 °C. o A homogeneous mixture was obtained by sonication at C for 30 min. An appropriate amount of the mixture was then cast onto a glass plate to form a film. The sample was first placed in a forced-air oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by holding the sample at 200°C for 12 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping content of 1.00 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0051] Example 5 Taking the preparation of a FPE / HAT-CN blend dielectric energy storage polymer film (HAT-CN doping content of 1.50 wt%) as an example, the specific preparation method is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 To prepare a polymer solution, weigh 6.0 mg of HAT-CN powder and dissolve it in 12 mL of NMP to obtain a concentration of 2 mg / mL. -1 Small molecule solutions, both solutions at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 h, a small molecule solution (HAT-CN doping amount of 1.50 wt%) was measured and added to the polymer solution. Stirring continued for another 2 h, followed by stirring at 150 W / 3500 ppm. o A homogeneous mixture was obtained by sonication at C for 40 min. An appropriate amount of the mixture was then cast onto a glass plate to form a film. The sample was first placed in a forced-air oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. oThe solvent was dried by maintaining a temperature of 18°C ​​for 18 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping content of 1.50 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0052] Example 6 Taking the preparation of a FPE / HAT-CN blend dielectric energy storage polymer film (HAT-CN doping content of 1.75 wt%) as an example, the specific preparation method is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 To prepare a polymer solution, weigh 7.0 mg of HAT-CN powder and dissolve it in 14 mL of NMP to obtain a concentration of 2 mg / mL. -1 Small molecule solutions, both solutions at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 h, a small molecule solution (HAT-CN doping amount of 1.75 wt%) was added to the polymer solution. Stirring continued for another 2 h, followed by stirring at 200 W / 40 °C. o A homogeneous mixture was obtained by sonication at C for 50 min. An appropriate amount of the mixture was then cast onto a glass plate to form a film. The sample was first placed in a forced-air oven at 40°C. o Preheat the oven to 80°C for 1 hour, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by maintaining a temperature of 24°C for 24 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping content of 1.75 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0053] Example 7 Taking the preparation of a FPE / HAT-CN blend dielectric energy storage polymer film (HAT-CN doping amount of 2.00 wt%) as an example, the specific preparation method is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 To prepare a polymer solution, weigh 8.0 mg of HAT-CN powder and dissolve it in 16 mL of NMP to obtain a concentration of 2 mg·mL⁻¹. -1 Small molecule solutions, both solutions at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 h, a small molecule solution (HAT-CN doping concentration of 2.00 wt%) was added to the polymer solution. Stirring continued for another 2 h, followed by stirring at 350 W / 50 °C. o A homogeneous mixture was obtained by sonication at C for 60 min. An appropriate amount of the mixture was then cast onto a glass plate to form a film. The sample was first placed in a forced-air oven at 50°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by maintaining a temperature of 24°C for 24 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 20°C for 24 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping content of 2.00 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0054] Comparative Example 1 The specific preparation method of FPE film is as follows: Weigh 0.40 g of FPE powder and dissolve it in 16 mL of NMP to prepare a solution with a concentration of 25 mg / mL. -1 The polymer solution, the solution at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 hours, a suitable amount of solution was measured and cast onto a glass plate to form a film. The sample was first placed in a forced-air drying oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by holding the sample at 200°C for 12 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. oVacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, an FPE film with a thickness of 10 μm was obtained. The FPE used in this example was manufactured by Polyk Corporation, USA.

[0055] Comparative Example 2 The specific preparation method of PI film is as follows: Weigh 0.40 g of PI powder and dissolve it in 10 mL of NMP to prepare a 10 mg·mL solution. -1 The polymer solution, the solution at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 hours, a suitable amount of solution was measured and cast onto a glass plate to form a film. The sample was first placed in a forced-air drying oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by holding the sample at 200°C for 12 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. o Vacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, a PI film with a thickness of 10 μm was obtained. The PI used in this example was manufactured by Polyk Corporation, USA.

[0056] Comparative Example 3 The specific preparation method for polyetherimide (PEI) films is as follows: Weigh 0.40 g of PEI powder and dissolve it in 10 mL of NMP to prepare a solution with a concentration of 10 mg / mL. -1 The polymer solution, the solution at 50 o C at 300 rpm·min -1 After magnetic stirring at a constant rate for 8 hours, a suitable amount of solution was measured and cast onto a glass plate to form a film. The sample was first placed in a forced-air drying oven at 40°C. o Preheat oven to 80°C for 30 minutes, then adjust the oven temperature program to 80°C. o Keep warm at 125°C for 8 hours. o Keep warm at 150°C for 1 hour. o Keep warm at 200°C for 1 hour. o The solvent was dried by holding the sample at 200°C for 12 hours. After cooling to room temperature in the furnace, the glass plate with the sample attached was placed in a vacuum oven at 200°C. oVacuum annealing at 1°C for 12 hours, followed by cooling to room temperature, then immersing the film in deionized water. After the film detaches, place it in an oven at 40°C. o After drying at C for 3 h, a PEI film with a thickness of 10 μm was obtained. The PEI used in this example was manufactured by Polyk Corporation, USA.

[0057] Comparison of high-temperature dielectric energy storage performance: Dielectric spectra were collected at different frequencies (from 100 Hz to 1 MHz) and temperatures using a Keysight E4980A LCR meter. The LCR meter was equipped with a heating rate of 1... o C·min -1 The oven was connected to the sample. The hysteresis loop and charge-discharge cycle performance of the sample were tested using a BoTai 610C high-voltage amplifier and a BoTai WGCM-20B ferroelectric tester. During the hysteresis loop test, the frequency was 100 Hz and the electric field strength was from 50 MV·m. -1 Start at 50 MV·m -1 The voltage is increased incrementally until it reaches the upper limit (10000 V) or the sample breaks down. The hysteresis loop is calculated by integration to obtain the discharge energy density and charge / discharge efficiency of different composite materials under different electric fields.

[0058] Figure 6 The temperature-varying dielectric spectra of Examples 1-4 and Comparative Examples 1-3 are shown. The dielectric constants (3.6-3.8) of the films obtained in Examples 1-4 are all better than those of Comparative Examples 1-3 (3.4-3.5), and the losses do not change significantly, remaining below 0.01.

[0059] Figure 7 Examples 1-4 and Comparative Examples 1-3 were tested at 200°C. o Dielectric spectra at different frequencies at time C. The dielectric constants of the films obtained in Examples 1-4 are all better than those in Comparative Examples 1-3, and the losses show no significant change.

[0060] Figure 8 Examples 1-4 and Comparative Examples 1-3 were subjected to a temperature of 150°C. o Energy storage performance diagram at C. The energy storage density of the films obtained in Examples 1-4 is better than that of Comparative Examples 1-3, especially that of Example 2 at 150. o C and 650 MV·m -1 It has 7.31 J·cm -3 The discharge energy density (charge-discharge efficiency greater than 90%).

[0061] Figure 9 Examples 1-4 and Comparative Examples 1-3 were tested at 200°C. o Energy storage performance diagram at C. The energy storage density of the films obtained in Examples 1-4 is superior to that of Comparative Examples 1-3, especially that of Example 2 at 200.o C and 550 MV·m -1 It has 5.16 J·cm -3 The discharge energy density (charge-discharge efficiency greater than 90%).

[0062] Figure 10 Examples 1-4 and Comparative Examples 1-3 were subjected to a temperature of 150°C. o Weibull distribution diagram of DC breakdown field strength at time C. Using the formula... P ( E )=1-exp(-( E b / α ) β Fitting is performed, where, P ( E ) is the cumulative probability of electrical breakdown. E b This is the experimentally measured electric field strength, and parameter α is the breakdown field strength at which the sample has a cumulative breakdown probability of 62.8%. β It can be used to determine the dispersion of data. The breakdown field strength of the films obtained in Examples 1-4 is better than that of Comparative Examples 1-3, especially that of Example 2 at 150 o The breakdown field strength at time C is 689.61 MV·m. -1 This is significantly higher than that of Comparative Example 1 (FPE, 516.41 MV·m). -1 Comparative Example 2 (PI, 480.38 MV·m) -1 ) and Comparative Example 3 (PEI, 350.71 MV·m -1 ).

[0063] Figure 11 Examples 1-4 and Comparative Examples 1-3 were tested at 200°C. o Weibull distribution diagram of DC breakdown field strength at C. The breakdown field strength of the films obtained in Examples 1-4 is better than that of Comparative Examples 1-3, especially that of Example 2 at 200. o The breakdown field strength at time C is 601.96 MV·m. -1 This is significantly higher than that of Comparative Example 1 (FPE, 491.40 MV·m). -1 Comparative Example 2 (PI, 385.45 MV·m) -1 ) and Comparative Example 3 (PEI, 257.86 MV·m -1 ).

[0064] Figure 12 Example 2 and Comparative Example 1 were compared at 200 o Comparison of cycling performance of C. The film obtained in Example 2 at 200... o C / 400 MV m -1Under the same conditions, it can maintain its high-temperature energy storage performance after 100,000 charge-discharge cycles, which is far superior to Comparative Example 1 (which can only cycle about 74,000 times under the same conditions and its performance is unstable).

[0065] Figure 13 Examples 1-4 of the present invention and Comparative Example 1 were respectively at 150°C o C and 200 o Comparison of high-temperature mechanical storage modulus of C. The breakdown field strength of the films obtained in Examples 1-4 is better than that of Comparative Example 1, especially Example 4 at 150°C. o The energy storage modulus at time C reaches 2008.83 MPa, far exceeding that of Comparative Example 1 (934.72 MPa), and is at 200 o The energy storage modulus at time C reaches 1815.34 MPa, which is much higher than that of Comparative Example 1 (825.31 MPa).

[0066] Table 1 shows the results of Examples 1-4 and Comparative Examples 1-3 at 150°C. o C and 200 o C's penetration field strength and U 90 The breakdown field strength of the films obtained in Examples 1-4 is superior to that of Comparative Examples 1-3, especially that of Example 2 at 150°C. o The breakdown field strength at time C is 689.61 MV·m. -1 This is significantly higher than that of Comparative Example 1 (FPE, 516.41 MV·m). -1 Comparative Example 2 (PI, 480.38 MV·m) -1 ) and Comparative Example 3 (PEI, 350.71 MV·m -1 ).

[0067] Table 1 Breakdown Field Strength U 90

[0068] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An all-organic composite material, characterized by, The all-organic composite material comprises, by mass fraction: 98.00 wt% to 99.75 wt% of fluorene polyester, and 0.25 wt% to 2.00 wt% of hexacyanohexaazatriphenylene.

2. The all-organic composite of claim 1, wherein, The all-organic composite material comprises, by mass fraction: 99.00 wt% to 99.75 wt% of fluorene polyester, and 0.25 wt% to 1.00 wt% of hexacyanohexaazatriphenylene.

3. The all-organic composite material according to claim 1 or 2, wherein The average molecular weight of the fluorene polyester is 5000 to 20000.

4. A process for the preparation of a wholly organic composite material as claimed in any one of claims 1 to 3, characterised in that, The method comprises the following steps: (1) by mass fraction, fluorene polyester and hexacyanohexaazatriphenylene are respectively added to an organic solvent and stirred to dissolve, and then mixed to obtain a mixed solution; (2) the mixed solution is uniformly coated on a substrate, then dried, and the dried composite film is vacuum annealed; (3) the composite film after vacuum annealing is peeled off from the substrate, and then dried to obtain the fluorene polyester / hexacyanohexaazatriphenylene all-organic composite material.

5. The production method according to claim 4, wherein The drying in step (2) is specifically: first preheating for 20-60 min at 30-50 o C, then drying for 8-12 h at 60-80 o C to remove the solvent, then baking for 1-2 h at 110-125 o C and 135-155 o C respectively, and finally baking for 12-24 h at 180-200 o C; the vacuum annealing temperature is 120-200 o C, and the time is 12-24 h.

6. The production method according to claim 4, wherein The ratio of the sum of the mass of the fluorene polyester and hexacyanohexaazatriphenylene in step (1) to the volume of the organic solvent is 20-40 mg-mL -1 .

7. The production method according to claim 4, wherein The temperature during stirring and dissolving in step (1) is 35-60 o C, and the stirring time is 8-12 h; the mixed solution is obtained by ultrasonic mixing, the ultrasonic temperature is 30-50 o C, the ultrasonic time is 30-60 min, and the ultrasonic power is 100-350 W.

8. The production method according to claim 4, wherein The organic solvent in step (1) is dimethylformamide, a combination of one or both of methylpyrrolidone.

9. The production method according to any one of claims 4 to 8, wherein The peeling method in step (3) is: after vacuum annealing, the composite film is immersed in deionized water, the composite film is peeled from the substrate, then the composite film is taken out and dried to remove water, the temperature for drying to remove water is 30-50 o C, and the time is 1-5 h.

10. A thin film capacitor characterized by The thin film capacitor adopts the all-organic composite material as claimed in any one of claims 1 to 3 as its polymer dielectric material.

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