All-organic composite material and preparation method and application thereof

Abstract

The application belongs to the field of thin film capacitors and related dielectric materials, and specifically discloses a kind of all-organic composite material and its preparation method and application, according to mass fraction, the all-organic composite material includes: 98.00wt%~99.75 wt% fluorene polyester and 0.25wt%~2.00 wt% hexacyanohexaazaphenanthrene.The preparation method includes: fluorene polyester and hexacyanohexaazaphenanthrene are added to organic solvent respectively, after being fully stirred and dissolved, ultrasonic mixing is obtained to obtain a uniform mixed solution;The mixed solution is uniformly coated on the substrate, heated, vacuum annealed and peeled off to obtain a fluorene polyester / hexacyanohexaazaphenanthrene composite film.The application improves the charge and discharge efficiency and discharge energy density of the polymer under high temperature and high electric field, solves the technical problems of high leakage loss and low charge and discharge efficiency of the existing polymer film, and is easy to realize large-scale industrial production.

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 gToo small, the charge captured at high temperature is easy to jump over the band gap, migrate even transfer to the polymer matrix in the filler, resulting in a decrease in breakdown strength, and high temperature energy storage performance is not ideal.

[0006] Therefore, it is urgent to develop a new functional filler with high E a and wide E g and excellent thermal stability, simple and environmentally friendly preparation process, to improve the capacitive energy storage performance of the composite system under high temperature and high electric field, which is a technical problem to be solved in the art. SUMMARY

[0007] In view of the above defects or improvement needs of the prior art, the present application provides a kind of all-organic composite material and its preparation method and application, its purpose is to improve the high temperature dielectric energy storage performance of composite dielectric energy storage material.

[0008] To achieve the above-mentioned purpose, according to the first aspect of the present application, an all-organic composite material is provided, which comprises, by mass fraction: 98.00wt% to 99.75wt% fluorene polyester, and 0.25wt% to 2.00wt% hexacyanohexaazaphenanthrene.

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

[0010] As a further preferred, the average molecular weight of the fluorene polyester is 5000 to 20000.

[0011] According to the second aspect of the present application, a preparation method of the above-mentioned all-organic composite material is provided, comprising the following steps:

[0012] (1) by mass fraction, the fluorene polyester and hexacyanohexaazaphenanthrene are respectively added to the organic solvent and stirred to dissolve, and then mixed to obtain a mixed solution;

[0013] (2) the mixed solution is uniformly coated on the substrate, then dried, and the composite film obtained by drying is vacuum annealed;

[0014] (3) the composite film after vacuum annealing is peeled off from the substrate, and then dried to obtain the fluorene polyester / hexacyanohexaazaphenanthrene all-organic composite material.

[0015] As a further preferred, the drying in step (2) is specifically: first preheated at 30 to 50 o C for 20 to 60 min, and then dried at 60 to 80 oC for 8-12 h to remove the solvent, and then baked at 110-125 o C for 1-2 h, and finally baked at 180-200 o C for 12-24 h; the vacuum annealing temperature is 120-200 o C, and the time is 12-24 h. o C for 8-12 h.

[0016] As a further preferred, the ratio of the sum of the mass of the fluorene polyester and hexacyanohexaazatriphenylene (HAT-CN) to the volume of the organic solvent in step (1) is 20-40 mg·mL -1 .

[0017] As a further preferred, the temperature is 35-60 o C during the stirring and dissolving in step (1), 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.

[0018] As a further preferred, the organic solvent in step (1) is one or a combination of the following: dimethylformamide, methylpyrrolidone.

[0019] As a further preferred, the peeling method in step (3) is that the composite film after vacuum annealing is soaked in deionized water to peel the composite film from the substrate, and then the composite film is taken out and dried to remove water, and the temperature for drying to remove water is 30-50 o C, and the time is 1-5 h.

[0020] According to a third aspect of the present application, a thin film capacitor is provided, which uses the above-mentioned all-organic composite material as its polymer dielectric material.

[0021] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0022] 1. The FPE / HAT-CN all-organic composite material of the present application, by introducing hexacyanohexaazatriphenylene (HAT-CN) with high E a and wide E g energy levels into fluorene polyester (FPE), builds a synergistic system of "precise charge capture-stable binding-enhanced dielectric performance", which helps to improve the high-temperature capacitive energy storage performance. The high E a energy level of HAT-CN is conducive to building deep energy level traps (such asFigure 2 and Figure 3 As 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.

[0023] 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.

[0024] 2. The mass fraction of FPE and HAT-CN in the composite material is designed, and the optimal proportion of HAT-CN is 0.25-2wt% based on the charge capture mechanism of HAT-CN and the characteristics of FPE matrix. Specifically, HAT-CN needs to be uniformly dispersed to form a "molecular level trap network" to achieve precise charge capture, and the effect depends on the dispersion state rather than the simple addition amount. When HAT-CN is less than 0.25wt%, the trap density is insufficient, and the free charge of FPE at high temperature cannot be effectively captured, the leakage current suppression effect is poor, and it is difficult to meet the high-temperature energy storage demand; when it is higher than 2wt%, HAT-CN molecules are easy to agglomerate due to π-π stacking, which not only destroys the FPE structure and leads to the decrease of breakdown strength, but also forms a charge migration channel, which increases the high-temperature dielectric loss. Within the range of 0.25-2wt%, HAT-CN can be uniformly dispersed in FPE, which can not only capture charges efficiently to improve the energy storage performance, but also enhance the mechanical stability of FPE at high temperature by virtue of the rigid nitrogen skeleton, realizing the synergistic optimization of "charge regulation-energy storage performance-mechanical property". E a and wide E g characteristics to capture charges efficiently to improve the energy storage performance, and enhance the mechanical stability of FPE at high temperature by virtue of the rigid nitrogen skeleton, realizing the synergistic optimization of "charge regulation-energy storage performance-mechanical property".

[0025] 3. The FPE / HAT-CN all-organic composite film is prepared by solution casting method, and the preparation process of HAT-CN is low in toxicity, so that the whole preparation process is simple, environmentally friendly and efficient, easy to industrial production, and has important application value in the fields of aerospace, oil exploitation and hybrid electric vehicles. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic diagram of the molecular structure of FPE and HAT-CN in the embodiment of the application.

[0027] Figure 2 It is a trap mechanism diagram formed inside the polymer material in the embodiment of the application.

[0028] Figure 3 It is a deep trap diagram formed inside the polymer material in the embodiment of the application.

[0029] Figure 4 It is a comparison diagram of HAT-CN and other molecular semiconductors in the embodiment of the application. E a and E g comparison diagram.

[0030] Figure 5 It is a thermal stability diagram of HAT-CN in the embodiment of the application.

[0031] Figure 6 It is a comparison diagram of 1-4 and 1-3 in the embodiment of the application at 25-200 oTemperature-dependent dielectric graph of C, in which the frequency is fixed at 1000 Hz.

[0032] Figure 7 The storage modulus of the inventive examples 1-4 and the comparative examples 1-3 at 200 o The dielectric spectrum of C at a frequency of 100-1 MHz.

[0033] Figure 8 The storage modulus of the inventive examples 1-4 and the comparative examples 1-3 at 150 o The storage modulus of C.

[0034] Figure 9 The storage modulus of the inventive examples 1-4 and the comparative examples 1-3 at 200 o The storage modulus of C.

[0035] Figure 10 The DC breakdown field strength of the inventive examples 1-4 and the comparative examples 1-3 at 150 o The Weibull distribution of the DC breakdown field strength of C.

[0036] Figure 11 The Weibull distribution of the DC breakdown field strength of the inventive examples 1-4 and the comparative examples 1-3 at 200 o The Weibull distribution of the DC breakdown field strength of C.

[0037] Figure 12 The cycle performance comparison of the inventive example 2 and the comparative example 1 at 200 o The cycle performance comparison of the inventive example 2 and the comparative example 1 at 200

[0038] Figure 13 The high-temperature mechanical storage modulus comparison of the inventive examples 1-4 and the comparative example 1 at 150 o C and 200 o C. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0040] The all-organic composite material provided by the embodiment of the present application comprises, by mass fraction: 98.00 wt% to 99.75 wt% fluorene polyester, and 0.25 wt% to 2.00 wt% hexacyanohexaazatriphenylene.

[0041] Further, the average molecular weight of the fluorene polyester is 5000-20000; preferably, the content of the fluorene polyester and hexacyanohexaazatriphenylene is 99.00-99.75 wt%, 0.25-1.00 wt%.

[0042] Specifically, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) is a “super electron acceptor” that is synergistically enhanced by the cyano group and the azatriphenylene skeleton, and the structural formula is as shown in Figure 1 The combination of HAT-CN and FPE forms a “structure adaptation-performance complementation” synergistic effect. The rigid azatriphenylene skeleton of HAT-CN has a natural π-π interaction matching property with the conjugated main chain of FPE, which can not only provide local structural support for FPE by relying on its rigidity, but also precisely adjust the π electron distribution through the N atoms in the skeleton, maintain the large conjugated structure while moderately confine the electron cloud, and specifically inhibit the charge conduction of the FPE conjugated skeleton at high temperature, avoiding the excessive delocalization of electrons and E g small problem; at the same time, the six peripheral cyano groups form a polar interaction with the ester groups of FPE, which not only strengthens the interface combination but also produces a strong synergistic electron-withdrawing effect, significantly reduces the LUMO level and synchronously regulates the HOMO level, and finally realizes high E a and wide E g positive synergy (as shown in Figure 4 ), which provides a molecular basis for efficiently capturing the free charges excited by FPE at high temperature. In addition, HAT-CN has excellent thermal stability (as shown in Figure 5 , there is no obvious thermal weight loss at 250 o C, and the temperature at which 5% of HAT-CN is thermally decomposed (T T d5 ) reaches 450 o C; and HAT-CN can be prepared by reacting cyclohexanehexone hydrate and diaminomaleonitrile, with a yield of 81%, a low toxicity in the preparation process and a simple process. HAT-CN has high E a and wide E g characteristics, and is an ideal organic functional filler for adapting to the high-temperature capacitive energy storage of polymers, which can fully meet the energy storage performance under high-temperature working conditions and the environmental protection production demand of industrialization.

[0043] The embodiment of the present application also provides a preparation method of the above-mentioned all-organic composite material, which comprises the following steps:

[0044] (1) FPE and HAT-CN are respectively added into an organic solvent, and after being fully stirred and dissolved, they are ultrasonically mixed to obtain a uniform mixed solution;

[0045] (2) The mixed solution obtained in step (1) is uniformly coated on a substrate, and then dried, and the dried composite film is further vacuum annealed;

[0046] (3) The composite film obtained in step (2) is peeled off, and then dried, thereby obtaining an FPE / HAT-CN composite film.

[0047] Further, the ratio of the sum of the mass of FPE and HAT-CN in the mixed solution to the volume of the solvent is 20-40 mg·mL -1 .

[0048] Further, the organic solvent is dimethylformamide, methylpyrrolidone, or a combination of any two thereof.

[0049] Further, the dissolution temperature in step (1) is 35-60 o C, and the stirring time is 8-12 h. Preferably, the ultrasonic temperature is 30-50 o C, the ultrasonic time is 30-60 min, and the ultrasonic power is 100-350 W. In the ultrasonic process, the power and the time 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, and agglomeration is easily formed, which is difficult to uniformly disperse subsequently; if the power is too high, the FPE molecular chain will be broken, resulting in a decrease in the mechanical properties of the matrix.

[0050] Further, in step (2), the drying conditions are as follows: first, preheating at 30-50 o C for 20-60 min, then drying at 60-80 o C for 8-12 h to remove the solvent, then baking at 110-125 o C and 135-155 o C for 1-2 h, respectively, and finally baking at 180-200 o C for 12-24 h. The baked composite film is transferred to a vacuum oven, and baked at 120-200 o C for 12-24 h to completely remove the residual solvent in the material.

[0051] For the temperature control of the above gradient drying: if the temperature is too low in the preheating stage, the water and solvent in the film layer cannot be released slowly, and bubbles and cracking may occur during the subsequent high-temperature drying due to rapid vaporization; if the temperature is too high, the surface of the film layer will be rapidly solidified, forming micropores due to the encapsulation of internal solvents, which will destroy the continuity of the charge capture network. In the subsequent drying and annealing stages, the temperature deviation will also affect the performance, and the temperature should be controlled in the range of 60-80 o C in the C solvent removal stage to avoid a sharp increase in dielectric loss caused by residual solvents during high-temperature drying; 110-125 o C / 135-155 o C in the stress relief stage to release the residual stress in the film and avoid curling of the film after film formation; 180-200 o C in the densification stage to strengthen the interfacial bonding between HAT-CN and FPE. These process parameters and mass fraction design form an efficient synergy, systematically avoiding defect risks at each stage, and further providing reliable process guarantees for the excellent comprehensive performance of the composite material.

[0052] Further, the peeling condition in step (3) is to immerse the annealed film in deionized water, and then dry and remove water after taking out the film, and the temperature for drying and removing water is 30-50 o C, and the time is 1-5 h.

[0053] In summary, the present application provides a full-organic composite material of fluorene polyester / hexacyanohexaazatriphenylene, which has excellent stability, filler with high E a and high E g temperature dielectric energy storage performance, and can overcome the problems of high leakage loss and low charge and discharge efficiency caused by the shortcomings of easy agglomeration, weak charge capture ability (inorganic nanoparticles), and high charge mobility under high electric field (traditional high E a low E g molecular semiconductors) in existing FPE-based composite dielectric energy storage materials.

[0054] The following are specific examples:

[0055] Example 1

[0056] Taking the preparation of a FPE and HAT-CN blended dielectric energy storage polymer film (HAT-CN doping amount is 0.25 wt%) as an example, the specific preparation method is as follows:

[0057] 0.40 g of FPE powder was dissolved in 16 mL of NMP to prepare a polymer solution with a concentration of 25 mg·mL -1 , and 1.0 mg of HAT-CN powder was dissolved in 2 mL of NMP to prepare a solution with 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 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. 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 0.25 wt% was obtained. The FPE used in this embodiment was manufactured by Polyk Inc., USA.

[0058] Example 2

[0059] 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:

[0060] 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. oC 1 h, 150 o C 1 h, 200 o C 12 h process to dry the solvent. After cooling down to room temperature in the oven, the glass plate with the sample was placed in a vacuum oven, 200 o C vacuum annealing for 12 h, after cooling down to room temperature, the film was immersed in deionized water. After the film was removed, it was placed in the oven for 40 o C After drying for 3 h, the FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping amount of 0.50 wt% was obtained. The FPE used in this example was produced by polyk company, USA.

[0061] Example 3

[0062] For example, to prepare a FPE and HAT-CN blended dielectric energy storage polymer film (HAT-CN doping amount of 0.75 wt%), the specific preparation method is as follows:

[0063] 0.40 g of FPE powder was dissolved in 16 mL of NMP to prepare a polymer solution with a concentration of 25 mg·mL -1 -1, and 3.0 mg of HAT-CN powder was dissolved in 6 mL of NMP to prepare a small molecule solution with a concentration of 2 mg·mL -1 -1. Both solutions were magnetically stirred at a speed of 300 rpm·min o -1 for 8 h at 50 -1 C. After 2 h of continuous stirring, a uniform mixed solution was obtained by ultrasonicating at 100 W / 30 o C for 30 min. An appropriate amount of mixed solution was cast on a glass plate to form a film. The sample was first placed in a convection oven at 40 o C for preheating for 30 min, and the oven temperature program was adjusted to 80 o C for 8 h, 125 o C for 1 h, 150 o C for 1 h, 200 o C for 12 h process to dry the solvent. After cooling down to room temperature in the oven, the glass plate with the sample was placed in a vacuum oven, 200 o C vacuum annealing for 12 h, after cooling down to room temperature, the film was immersed in deionized water. After the film was removed, it was placed in the oven for 40 o C After drying for 3 h, the FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping amount of 0.75 wt% was obtained. The FPE used in this example was produced by polyk company, USA.

[0064] Example 4

[0065] 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:

[0066] 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 -1 After 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.

[0067] Example 5

[0068] 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:

[0069] 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 oC 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. o The 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.

[0070] Example 6

[0071] 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:

[0072] 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 C The process oven dried the solvent for 24 h. After cooling to room temperature in the oven, the glass plate with the sample was placed in a vacuum oven at 200 o C vacuum annealed for 12 h, and after cooling to room temperature, the film was immersed in deionized water. After the film was removed, it was placed in an oven at 40 o C After drying for 3 h, the FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping amount of 1.75 wt% was obtained. The FPE used in this example was produced by the polyk company in the United States.

[0073] Example 7

[0074] For example, to prepare a FPE and HAT-CN blended dielectric energy storage polymer film (HAT-CN doping amount of 2.00 wt%), the specific preparation method is as follows:

[0075] 0.40 g of FPE powder was dissolved in 16 mL of NMP to prepare a polymer solution with a concentration of 25 mg·mL -1 mg of HAT-CN powder was dissolved in 16 mL of NMP to prepare a small molecule solution with a concentration of 2 mg·mL -1 The two solutions were magnetically stirred at 300 rpm·min -1 for 8 h at 50 o C. After 2 h of continuous stirring, a uniform mixed solution was obtained by ultrasonicating at 350 W / 50 o C for 60 min. An appropriate amount of the mixed solution was cast on a glass plate to form a film. The sample was first preheated in a convection oven at 50 o C for 30 min, and the oven temperature program was adjusted to 80 o C for 8 h, 125 o C for 1 h, 150 o C for 1 h, 200 o C for 24 h. After cooling to room temperature in the oven, the glass plate with the sample was placed in a vacuum oven at 200 o C for 24 h, and after cooling to room temperature, the film was immersed in deionized water. After the film was removed, it was placed in an oven at 40 o C for 3 h, the FPE / HAT-CN composite film with a thickness of 10 μm and a HAT-CN doping amount of 2.00 wt% was obtained. The FPE used in this example was produced by the polyk company in the United States.

[0076] Comparative Example 1

[0077] FPE film, the specific preparation method is as follows:

[0078] 0.40 g of FPE powder is weighed and dissolved in 16 mL of NMP to prepare a polymer solution with a concentration of 25 mg·mL -1 After the solution is magnetically stirred at a rate of 300 rpm·min o for 8 h at 50 -1 C, an appropriate amount of solution is cast on a glass plate to lay a film. The sample is first placed in a forced air oven at 40 o C for preheating for 30 min, and the oven temperature program is adjusted to 80 o C for 8 h, 125 o C for 1 h, 150 o C for 1 h, and 200 o C for 12 h to dry the solvent. After the furnace is cooled to room temperature, the glass plate with the sample is placed in a vacuum oven, vacuum annealed at 200 o C for 12 h, and after being cooled to room temperature, the film is immersed in deionized water. After the film is removed, it is placed in an oven at 40 o C for drying for 3 h, and a FPE film with a thickness of 10 μm is obtained. The FPE used in this example is produced by polyk company of the United States.

[0079] Comparative Example 2

[0080] PI film, the specific preparation method is as follows:

[0081] 0.40 g of PI powder is weighed and dissolved in 10 mL of NMP to prepare a polymer solution with a concentration of 10 mg·mL -1 After the solution is magnetically stirred at a rate of 300 rpm·min o for 8 h at 50 -1 C, an appropriate amount of solution is cast on a glass plate to lay a film. The sample is first placed in a forced air oven at 40 o C for preheating for 30 min, and the oven temperature program is adjusted to 80 o C for 8 h, 125 o C for 1 h, 150 o C for 1 h, and 200 o C for 12 h to dry the solvent. After the furnace is cooled to room temperature, the glass plate with the sample is placed in a vacuum oven, vacuum annealed at 200 o C for 12 h, and after being cooled to room temperature, the film is immersed in deionized water. After the film is removed, it is placed in an oven at 40 o C for drying for 3 h, and a PI film with a thickness of 10 μm is obtained. The PI used in this example is produced by polyk company of the United States.

[0082] Comparative Example 3

[0083] The specific preparation method for polyetherimide (PEI) films is as follows:

[0084] 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. 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 PEI film with a thickness of 10 μm was obtained. The PEI used in this example was manufactured by Polyk Corporation, USA.

[0085] Comparison of high-temperature dielectric energy storage performance:

[0086] 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.

[0087] 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.

[0088] Figure 7 The dielectric spectra of different frequencies at 200 o C for Examples 1-4 and Comparative Examples 1-3. The dielectric constants of the thin films obtained in Examples 1-4 are all better than those of Comparative Examples 1-3, and the loss does not change significantly.

[0089] Figure 8 The energy storage performance graphs at 150 o C for Examples 1-4 and Comparative Examples 1-3. The energy storage densities of the thin films obtained in Examples 1-4 are all better than those of Comparative Examples 1-3, especially the energy storage density of Example 2 at 150 o C and 650 MV·m -1 has a discharge energy density of 7.31 J·cm -3 (-90% charge-discharge efficiency).

[0090] Figure 9 The energy storage performance graphs at 200 o C for Examples 1-4 and Comparative Examples 1-3. The energy storage densities of the thin films obtained in Examples 1-4 are all better than those of Comparative Examples 1-3, especially the energy storage density of Example 2 at 200 o C and 550 MV·m -1 has a discharge energy density of 5.16 J·cm -3 (-90% charge-discharge efficiency).

[0091] Figure 10 The Weibull distribution graphs of the direct current breakdown field strength at 150 o C for Examples 1-4 and Comparative Examples 1-3. The formula P ( E ) = 1-exp(-( E b / α ) β ) is used for fitting, where, P ( E ) is the cumulative probability of electrical breakdown, E b is the experimentally measured electric field strength, the parameter a is the breakdown field strength at which the cumulative breakdown probability of the sample is 62.8%, and the parameter β can be used to judge the dispersion of the data. The breakdown field strengths of the thin films obtained in Examples 1-4 are all better than those of Comparative Examples 1-3, especially the breakdown field strength of Example 2 at 150 o C is 689.61 MV·m -1 , which is much 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 ).

[0092] Figure 11 The Weibull distribution diagram of the direct current breakdown field strength of Examples 1-4 and Comparative Examples 1-3 at 200 o C is shown in FIG. 2. The breakdown field strength of the thin films obtained in Examples 1-4 is superior to that of Comparative Examples 1-3, and in particular, the breakdown field strength of Example 2 at 200 o C is 601.96 MV·m -1 , which is much 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 ).

[0093] Figure 12 The cycle performance comparison diagram of Example 2 and Comparative Example 1 at 200 o C is shown in FIG. 3. The thin film obtained in Example 2 can maintain high-temperature energy storage performance after 100,000 times of charge-discharge cycles under the condition of 200 o C / 400 MV m -1 , which is much better than that of Comparative Example 1 (which can only be cycled about 74,000 times and has unstable performance under the same condition).

[0094] Figure 13 The high-temperature mechanical energy storage modulus comparison diagram of Examples 1-4 and Comparative Example 1 at 150 o C and 200 o C is shown in FIG. 4. The breakdown field strength of the thin films obtained in Examples 1-4 is superior to that of Comparative Example 1, and in particular, the energy storage modulus of Example 4 at 150 o C is 2008.83 MPa, which is much higher than that of Comparative Example 1 (934.72 MPa), and the energy storage modulus at 200 o C is 1815.34 MPa, which is much higher than that of Comparative Example 1 (825.31 MPa).

[0095] Table 1 is the breakdown field strength and U 90 of Examples 1-4 and Comparative Examples 1-3 at 150 o C and 200 o C. The breakdown field strength of the thin films obtained in Examples 1-4 is superior to that of Comparative Examples 1-3, and in particular, the breakdown field strength of Example 2 at 150 o C is 689.61 MV·m -1 , which is much 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 ).

[0096] Table 1 Breakdown field strength and U 90

[0097]

[0098] It is readily understood by those skilled in the art that the above description is only preferred embodiments of the application and is not intended to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application should be included in the protection scope of the application.

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; the average molecular weight of the fluorene polyester is 5000 to 20000, and the molecular structure of the fluorene polyester is: The all-organic composite material is prepared by the following method: (1) by mass fraction, the fluorene polyester and the hexacyanohexaazatriphenylene are respectively added to an organic solvent to be stirred and dissolved, and then mixed to obtain a mixed solution; (2) the mixed solution is uniformly coated on a substrate, and then gradient drying is performed, 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.

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 of claim 1, wherein In step (2), the drying is specifically: first preheating at 30 to 50℃ for 20 to 60 min, then drying at 60 to 80℃ for 8 to 12 h to remove the solvent, then baking at 110 to 125℃ and 135 to 155℃ for 1 to 2 h respectively, and finally baking at 180 to 200℃ for 12 to 24 h; the vacuum annealing temperature is 120 to 200℃, and the time is 12 to 24 h.

4. The all-organic composite of claim 1, 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 .

5. The all-organic composite of claim 1, wherein In step (1), the stirring and dissolving is at a temperature of 35 to 60℃ for 8 to 12 h; the mixed solution is obtained by ultrasonic mixing, the ultrasonic temperature is 30 to 50℃, the ultrasonic time is 30 to 60 min, and the ultrasonic power is 100 to 350 W.

6. The all-organic composite of claim 1, wherein, In step (1), the organic solvent is one of N,N-dimethylformamide and N-methylpyrrolidone or a combination of the two.

7. The all-organic composite of claim 1, wherein In step (3), the peeling method is: the composite film after vacuum annealing is soaked in deionized water to make the composite film peeled off from the substrate, then the composite film is taken out and dried to remove water, the temperature for drying to remove water is 30 to 50℃, and the time is 1 to 5 h.

8. A thin film capacitor characterized by The film capacitor uses the all-organic composite material as claimed in any one of claims 1 to 7 as its polymer dielectric material.

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