Method for preparing BaTiO3 / KNbO3 / PI high-temperature-resistant flexible nano composite film based on in-situ polymerization method
The BaTiO3/KNbO3/PI nanocomposite film was prepared by in-situ polymerization, which solved the problems of low breakdown field strength and low energy density of nanocomposite energy storage materials in high temperature environments in the existing technology, achieved efficient charge separation and transport, and improved the energy storage performance and high temperature resistance of the composite film.
Patent Information
- Application Number
- CN202510893094.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-09-26
AI Technical Summary
Existing organic/inorganic nanocomposite energy storage materials have problems such as low breakdown field strength, low energy density, and slow charging and discharging efficiency under high power, high current and ultra-high temperature environments. The introduction of inorganic fillers leads to a decrease in breakdown field strength and an increase in leakage conductivity.
BaTiO3/KNbO3/PI nanocomposite films were prepared by in situ polymerization, and BaTiO3/KNbO3 composites with heteroepitaxial interfaces were prepared by solvothermal method. BaTiO3/KNbO3 composite fillers were used to construct pn heterojunctions to disperse the electrical tree breakdown paths and capture charge carriers.
It improves the breakdown field strength, enhances the separation and transport of charge carriers, suppresses leakage conduction, improves energy storage performance and high temperature resistance, and is suitable for electronic equipment.
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Figure CN120699298A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of nanocomposite materials, and in particular relates to a method for preparing a BaTiO3 / KNbO3 / PI high-temperature resistant flexible nanocomposite film based on an in-situ polymerization method. Background Art
[0002] Dielectric capacitors are widely used in electronic devices and power systems due to their fast charge and discharge rates and high power density. They play an irreplaceable role in aerospace, hybrid vehicles, wind power generation and other fields. However, in practical applications, dielectric capacitors often encounter harsh environments such as high power, high current and ultra-high temperature. In recent years, the organic polymer polyimide (PI) has been widely used due to its high glass transition temperature (T g ) and has received significant attention. In addition, the E b An order of magnitude higher than traditional materials. However, this performance is often hindered by low dielectric constant and limited polarization value, which limits its U e The introduction of inorganic ceramic fillers with high dielectric constant is one of the most effective strategies to solve this problem.
[0003] Currently, the development of organic / inorganic nanocomposite energy storage materials is attracting increasing attention from researchers. However, the research on organic / inorganic nanocomposite energy storage materials still faces some technical bottlenecks. For example, due to the agglomeration or uneven dispersion of inorganic fillers, the introduction of inorganic ceramic fillers often leads to a decrease in breakdown field strength and an increase in leakage conductivity. In addition, the large difference in dielectric constant between organic polymers and inorganic fillers can also lead to an increase in local polarization in the composite material, resulting in a decrease in the performance of the inorganic / organic nanocomposite. Summary of the Invention
[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for preparing a high-temperature resistant and flexible nano-composite film of barium titanate / potassium niobate / polyimide (BaTiO3 / KNbO3 / PI) based on an in-situ polymerization method. The nano-composite film uses a BaTiO3 / KNbO3 nano-composite with a two-dimensional lamellae morphology and a zero-dimensional granular morphology as a filler. The two-dimensional morphology can well disperse the breakdown path of electrical dendrites. In addition, the pn heterojunction constructed by the BaTiO3 / KNbO3 composite filler effectively captures the transport of charge carriers, thereby solving the problems of low breakdown field strength, low energy density, and slow charge and discharge efficiency existing in the existing process.
[0005] In order to achieve the above technical purpose, the inventors conducted a lot of basic experimental research and first used titanium dioxide (TiO2), barium hydroxide octahydrate (Ba(OH) 2·BaTiO₃ / KNbO₃ composites with heteroepitaxial interfaces were successfully prepared via a solvothermal method using 8H₂O), niobium pentoxide (Nb₂O₅), and potassium hydroxide (KOH) as raw materials. Subsequently, flexible BaTiO₃ / KNbO₃ / PI nanocomposite films were prepared by in situ polymerization using 4,4'-diaminodiphenyl ether (ODA) and pyromellitic dianhydride (PMDA) as diamine and dianhydride monomers, respectively, and N,N-dimethylacetamide (DMAc) as the reaction solvent. Furthermore, by optimizing the effects of raw material ratios, reaction time, and solid content on the composite and film, methods for preparing BaTiO₃ / KNbO₃ composites with heteroepitaxial interfaces and flexible BaTiO₃ / KNbO₃ / PI nanocomposite films were developed.
[0006] Specifically, the technical solution for achieving the purpose of the present invention is as follows: a method for preparing a BaTiO3 / KNbO3 / PI high-temperature resistant flexible nanocomposite film based on an in-situ polymerization method, the method comprising the following steps:
[0007] (1) Preparation of BaTiO3 / KNbO3 composite by solvent thermal method: TiO2, Ba(OH) 2· 8H2O, Nb2O5, and KOH were placed in a polytetrafluoroethylene-lined reactor, and isopropanol was added as the reaction solvent. After stirring for 0.5-2 hours, the mixture was transferred to a homogeneous reactor and subjected to a solvothermal reaction at 190-210°C for 8-16 hours. After cooling to room temperature, the product was washed several times with deionized water, 3%-5% acetic acid, and anhydrous ethanol. The resulting product was dried in a drying oven at 55-65°C for 8-16 hours to obtain a BaTiO3 / KNbO3 complex with a heteroepitaxial interface.
[0008] (2) Preparation of BaTiO3 / KNbO3 / PI flexible nanocomposite film by in situ polymerization: ODA was dissolved in DMAc solvent to obtain ODA-DMAc solution; PMDA and the BaTiO3 / KNbO3 complex obtained in step (1) were added to DMAc solvent and stirred to obtain BaTiO3 / KNbO3-PMDA-DMAc solution; the ODA-DMAc solution was uniformly transferred to the BaTiO3 / KNbO3-PMDA-DMAc solution in 3-6 times within 1 h, and ultrasonicated and stirred alternately for a total of 18-30 h in an ice-water bath to obtain a viscous BaTiO3 / KNbO3 / polyamic acid (PAA) slurry. After removing bubbles from the slurry, the slurry was poured onto a glass substrate and evenly coated with a scraper. It was then dried to remove the solvent and transferred to a muffle furnace for heat treatment at 90-110 ℃, 190-210 ℃ and 290-310 ℃, respectively. ℃ for 0.8-1.2 h to completely convert PAA into PI; after cooling naturally to room temperature, the film was taken out of the furnace and immersed in deionized water, and then peeled off to obtain the BaTiO3 / KNbO3 / PI flexible nanocomposite film.
[0009] Further preferably, in the method for preparing BaTiO3 / KNbO3 / PI high temperature resistant flexible nanocomposite film based on in situ polymerization as described above, in step (1), Ba(OH) 2· The molar ratio of 8H2O and TiO2 = 1.28:1.
[0010] Further preferably, in the method for preparing the high-temperature-resistant flexible BaTiO3 / KNbO3 / PI nanocomposite film based on the in-situ polymerization method as described above, the solvent thermal reaction temperature in step (1) is 200°C.
[0011] Further preferably, in the method for preparing the BaTiO3 / KNbO3 / PI high temperature resistant flexible nanocomposite film based on the in situ polymerization method as described above, the solvent thermal reaction time in step (1) is 11-13 h.
[0012] Further preferably, in the method for preparing the BaTiO3 / KNbO3 / PI high temperature resistant flexible nanocomposite film based on the in situ polymerization method as described above, the molar ratio of ODA and PMDA when mixed in step (2) is 1: (1.02-1.05).
[0013] Further preferably, in the method for preparing the BaTiO3 / KNbO3 / PI high temperature resistant flexible nanocomposite film based on the in situ polymerization method as described above, the ratio of the amount of PMDA in step (2) to the BaTiO3 / KNbO3 composite obtained in step (1) is 1:1.
[0014] Further preferably, in the method for preparing the BaTiO3 / KNbO3 / PI high temperature resistant flexible nanocomposite film based on the in situ polymerization method as described above, in step (2), the alternating ultrasound and stirring are performed for a total of 22-26 hours.
[0015] Further preferably, in the method for preparing the BaTiO3 / KNbO3 / PI high temperature resistant flexible nanocomposite film based on the in situ polymerization method as described above, the heat treatment temperature in the muffle furnace in step (2) is 100°C, 200°C and 300°C for 1 h each.
[0016] Compared with the existing methods, the process for preparing BaTiO3 / KNbO3 / PI high temperature resistant flexible nanocomposite film based on in situ polymerization provided by the present invention has the following advantages and significant progress:
[0017] (1) TiO2, Ba(OH) 2· 8H2O, Nb2O5 and KOH were successfully used to prepare BaTiO3 / KNbO3 composites with heteroepitaxial interfaces via a solvothermal method, providing an alternative inorganic filler for the preparation of PI-based nanocomposite films.
[0018] (2) Through TiO2, Ba(OH) 2· The BaTiO3 / KNbO3 complex is directly prepared by a one-step hydrothermal reaction of the four raw materials 8H2O, Nb2O5 and KOH, which shortens the secondary hydrothermal process and greatly simplifies the preparation process of the BaTiO3 / KNbO3 complex.
[0019] (3) The flaky and granular morphologies of the prepared BaTiO3 / KNbO3 composites increased the specific surface area of the inorganic filler, effectively preventing the growth of electrical dendrites and improving the breakdown field strength of the BT / KN / PI composite film. In addition, the heterostructured BT / KN effectively promoted the separation of charge carriers through the pn heterojunction, inhibited the transport of charges, and improved the energy storage performance of the BT / KN / PI composite film.
[0020] (4) This process avoids the need for multi-step preparation of inorganic fillers and composite films and post-processing, and effectively reduces the leakage conduction of the composite film through morphology control and the construction of heterogeneous structures. The selection of PI also increases the temperature tolerance of the composite film, improving the overall energy storage performance. It also has certain piezoelectricity and can be used as an electronic component to power small light bulbs. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 :TiO2、Ba(OH) 2·(a) XRD pattern and (b) Raman spectrum of the sample obtained after 8H2O, Nb2O5 and KOH were uniformly mixed and reacted at 200 ℃ for 12 h;
[0022] Figure 2 :TiO2、Ba(OH) 2· (a) TEM image, (b) HRTEM image and (c) SAED spectrum of the sample obtained after 8H2O, Nb2O5 and KOH were uniformly mixed and reacted at 200 ℃ for 12 h;
[0023] Figure 3 : (a) XRD patterns and (b) FT-IR spectra of BaTiO3 / KNbO3 / PI nanocomposite films with different BaTiO3 / KNbO3 addition amounts;
[0024] Figure 4 : DE Loops curves of BaTiO3 / KNbO3 / PI nanocomposite films with different BaTiO3 / KNbO3 addition amounts at (a) room temperature, (b) 150 ℃ and (c) 200 ℃;
[0025] Figure 5 : (a) open circuit voltage and (b) short circuit current of BaTiO3 / KNbO3 / PI nanocomposite films with different BaTiO3 / KNbO3 addition amounts under an applied pressure of 9 N;
[0026] Figure 6 : Actual photo of BaTiO3 / KNbO3 / PI nanocomposite film lighting a small light bulb. DETAILED DESCRIPTION
[0027] The present invention will be further described in detail below by specific examples. However, it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. In addition, where specific technical operating steps or conditions are not indicated in the examples, they are all performed according to the technology or conditions described in the literature in this area or according to the product specifications. Reagents or instruments used that do not indicate the manufacturer are all conventional products that can be obtained commercially.
[0028] Example 1: Preparation of BaTiO3 / KNbO3 composite
[0029] Preparation of BaTiO3 / KNbO3 composite by solvothermal method: 0.2 g TiO2, 1.0 g Ba(OH) 2· 8H2O 0.4 g of Nb2O5, and 3 g of KOH were placed in a Teflon-lined reactor, and 25 mL of isopropanol was added as solvent. The mixed solution was stirred on a magnetic stirrer at 500 r / min for 1 h, then transferred to a homogeneous reactor and solvothermally reacted at 200°C for 12 h. After cooling to room temperature, the product was washed twice with deionized water, 4% acetic acid, and anhydrous ethanol. The resulting product was dried in a drying oven at 60°C for 12 h to obtain a BaTiO3 / KNbO3 composite with a heteroepitaxial interface.
[0030] Example 2: Research and Experiment on BaTiO3 / KNbO3 Composite
[0031] Through TiO2, Ba(OH) 2· 8H2O After Nb2O5 and KOH reacted at 200 ℃ for 12 h, the XRD pattern of the product was obtained. Figure 1 (a), the XRD diffraction peaks of the product are observed to be consistent with the standard cards of BaTiO3 and KNbO3 (ICDD No. 75-0213 and No. 32-0822). In addition, the BT / KN composite shows crystal planes corresponding to BT, specifically (100), (110), (111), (200), (201), (211) crystal planes corresponding to KN, that is, (110), (111), (021), (220), (221), (022) crystal planes. In the corresponding Raman spectrum. Figure 1 As shown in (b), the composite corresponds to the 186 and 253 cm -1 and 589 and 831 cm of KNbO3 -1 The changes in other peaks may be attributed to the recombination of the two phases.
[0032] Example 3: Study on the effect of reaction on the morphology of BaTiO3 / KNbO3 composite
[0033] TiO2, Ba(OH) 2· The phase structure of the product after 8H2O, Nb2O5 and KOH reacted at 200 ℃ for 12 h is as follows Figure 2 , TEM test results, such as Figure 2 (a), the presence of flakes and particles can be clearly seen. HRTEM test results are as follows Figure 2(b), the observed lattice fringe spacing is 2.35 μm and 2.83 μm, respectively, which are attributed to the (111) and (110) crystal planes of BaTiO3. In addition, lattice fringes with lattice spacing of 3.96 μm and 2.84 μm are also found, corresponding to the (001) and (200) crystal planes of KNbO3. In addition, obvious grain boundaries can be observed in the BaTiO3 / KNbO3 complex. SAED results are shown as follows Figure 2 As shown in (c), the reciprocal lattice points of BaTiO3 single crystal and the diffraction rings of KNbO3 polycrystal can be observed.
[0034] Example 4: Preparation of BaTiO3 / KNbO3 / PI nanocomposite film
[0035] BaTiO3 / KNbO3 / PI nanocomposite films were prepared by in-situ polymerization: ODA was used as the diamine monomer and PMDA as the dianhydride monomer, with a molar ratio of 1:1.05. Six portions of 1.0012 g (0.0050 mol) of ODA were weighed and dissolved in 4 mL of DMAc solvent. The mixture was stirred for 30 minutes to obtain an ODA-DMAc mixed solution. Six portions of 1.1451 g of PMDA were then weighed, and the BaTiO3 / KNbO3 composite prepared in Example 1 was weighed according to the desired amount of inorganic filler. 0g, 0.02g, 0.06g, 0.11g, 0.16g, and 0.21g of the BaTiO3 / KNbO3 complex were weighed and added to the six portions of 1.1451g (0.0053mol) of PMDA described above. The mixture was dissolved in 3.1mL of DMAc and stirred for 30 minutes to obtain a BaTiO3 / KNbO3-PMDA-DMAc mixed solution. The two solutions were thoroughly mixed by evenly transferring the ODA-DMAc solution to the BaTiO3 / KNbO3-PMDA-DMAc solution in five batches over 1 hour. Alternating ultrasonic stirring was performed in an ice-water bath at 0°C for 24 hours to obtain a viscous BaTiO3 / KNbO3 / PAA slurry, which was then placed in a vacuum drying oven for 30 minutes to remove bubbles. The BaTiO3 / KNbO3 / PAA slurry was then poured onto a glass substrate. The coating was evenly applied using a doctor blade, and the film thickness was controlled by adjusting the blade height. The film was then dried for 12 hours to remove the solvent and then transferred to a muffle furnace for heat treatment. Heating at 100°C, 200°C, and 300°C for 1 hour each completely converted PAA to PI. After cooling to room temperature, the film was removed from the furnace and immersed in deionized water. After exfoliation, a BaTiO₃ / KNbO₃ / PI flexible nanocomposite film was obtained.
[0036] Example 5: Research and Experiment on BaTiO3 / KNbO3 / PI Nanocomposite Film
[0037] The XRD patterns of BaTiO3 / KNbO3 / PI nanocomposite films with different BaTiO3 / KNbO3 addition amounts prepared by in situ polymerization are shown in Figure 2. Figure 3 As shown in (a), an amorphous diffraction peak is observed at about 20°, which is a typical characteristic peak of polymer PI. When the BaTiO3 / KNbO3 addition amount is 0 wt%, only a single peak corresponding to PI exists. As the BaTiO3 / KNbO3 content increases, the characteristic peak of BaTiO3 / KNbO3 gradually appears and strengthens. The FT-IR spectrum of the BaTiO3 / KNbO3 / PI nanocomposite film is shown in Figure 3 (b) shows the peaks at 1714, 1776, 1498, 1373, and 725 cm -1 Symmetrical C=O stretching, asymmetric C=O stretching, CC stretching, CN stretching, and CO stretching belonging to the imide group were observed, and the vibration peaks were sharp, indicating that the polymer had a high degree of imidization.
[0038] Example 6: Experimental study on the effect of test temperature on the energy storage performance of BaTiO3 / KNbO3 / PI nanocomposite films
[0039] The results of ferroelectric tests on the composite film at room temperature, 150 ℃ and 200 ℃ are shown in Figure 2. Figure 4 As shown. When the test conditions are set to room temperature, the DE Loops curve of BaTiO3 / KNbO3 / PI nanocomposite film presents a relatively narrow shape. When the addition amount of BaTiO3 / KNbO3 is 5 wt%, the energy density (U e ) reaches a maximum value of 5.45 J / cm 3 , η can reach 85.88%. When the temperature rises to 150 ℃, the electric field distortion in the composite film under high temperature and high electric field conditions causes its hysteresis loop to become "fat". U of 5 wt% BaTiO3 / KNbO3 / PI nanocomposite film e Still can reach 4.69 J / cm 3 , η is 68.1%. When the temperature rises to 200 ℃, the leakage conduction phenomenon becomes more obvious, and the U e 2.18 J / cm 3 .
[0040] Example 7: Experimental study on the effect of applied pressure on the piezoelectric properties of BaTiO3 / KNbO3 / PI nanocomposite films
[0041] The results of the piezoelectric performance test of BaTiO3 / KNbO3 / PI flexible nanocomposite films with different BaTiO3 / KNbO3 addition amounts are shown in the figure. Figure 5 When an external pressure of 9 N is applied to the composite film, the open circuit voltage results of all composite films tested are shown in Figure 5 As shown in (a), the maximum open circuit voltage of 7 wt% BaTiO3 / KNbO3 / PI flexible nanocomposite film can reach 0.62 V. The short circuit current test results of all composite films are shown in Figure 5 As shown in (b), the maximum short-circuit current of the 7 wt% BaTiO3 / KNbO3 / PI flexible nanocomposite film can reach 24.49 nA. When an external force is applied to the composite film, four 3 V small light bulbs can be lit at the same time. The actual test results are shown in the figure below. Figure 6 shown.
Claims
1. A method for preparing a high-temperature-resistant and flexible BaTiO3 / KNbO3 / PI nanocomposite film based on an in-situ polymerization method, characterized in that: The method includes the following steps: (1) Preparation of BaTiO3 / KNbO3 composite by solvent thermal method: TiO2, Ba(OH) 2· 8H2O, Nb2O5, and KOH were placed in a polytetrafluoroethylene-lined reactor, and isopropanol was added as the reaction solvent. After stirring for 0.5-2 hours, the mixture was transferred to a homogeneous reactor and subjected to a solvothermal reaction at 190-210°C for 8-16 hours. After cooling to room temperature, the product was washed several times with deionized water, 3%-5% acetic acid, and anhydrous ethanol. The resulting product was dried in a drying oven at 55-65°C for 8-16 hours to obtain a BaTiO3 / KNbO3 complex with a heteroepitaxial interface. (2) Preparation of BaTiO3 / KNbO3 / PI flexible nanocomposite film by in situ polymerization: ODA was dissolved in DMAc solvent to obtain ODA-DMAc solution; PMDA and the BaTiO3 / KNbO3 complex obtained in step (1) were added to DMAc solvent and stirred to obtain BaTiO3 / KNbO3-PMDA-DMAc solution; the ODA-DMAc solution was uniformly transferred to the BaTiO3 / KNbO3-PMDA-DMAc solution in 3-6 times within 1 h, and ultrasonicated and stirred alternately for a total of 18-30 h in an ice-water bath to obtain a viscous BaTiO3 / KNbO3 / PAA slurry. After removing bubbles from the slurry, the slurry was poured onto a glass substrate and evenly coated with a scraper. It was then dried to remove the solvent and transferred to a muffle furnace for heat treatment at 90-110 ℃, 190-210 ℃ and 290-310 ℃, respectively. ℃ for 0.8-1.2 h to completely convert PAA into PI; after cooling naturally to room temperature, the film was taken out of the furnace and immersed in deionized water, and then peeled off to obtain the BaTiO3 / KNbO3 / PI flexible nanocomposite film.
2. The method for preparing a high temperature resistant flexible BaTiO3 / KNbO3 / PI nanocomposite film based on in situ polymerization according to claim 1, characterized in that: Ba(OH) in step (1) 2· The molar ratio of 8H2O and TiO2 = 1.28:
1.
3. The method for preparing a high temperature resistant flexible BaTiO3 / KNbO3 / PI nanocomposite film based on in situ polymerization according to claim 1, characterized in that: The solvent thermal reaction temperature in step (1) is 200 °C.
4. The method for preparing a high temperature resistant and flexible BaTiO3 / KNbO3 / PI nanocomposite film based on in situ polymerization according to claim 1, characterized in that: The solvent thermal reaction time in step (1) is 11-13 h.
5. The method for preparing a high temperature resistant and flexible BaTiO3 / KNbO3 / PI nanocomposite film based on in situ polymerization according to claim 1, characterized in that: The molar ratio of ODA and PMDA when mixed in step (2) is 1: (1.02-1.05).
6. The method for preparing a high temperature resistant and flexible BaTiO3 / KNbO3 / PI nanocomposite film based on in situ polymerization according to claim 1, characterized in that: The usage ratio of PMDA in step (2) and the BaTiO3 / KNbO3 complex obtained in step (1) is 1:
1.
7. The method for preparing a high temperature resistant and flexible BaTiO3 / KNbO3 / PI nanocomposite film based on in situ polymerization according to claim 1, characterized in that: In step (2), alternate sonication and stirring for a total of 22-26 h.
8. The method for preparing a high temperature resistant and flexible BaTiO3 / KNbO3 / PI nanocomposite film based on in situ polymerization according to claim 1, characterized in that: In step (2), the heat treatment temperature in the muffle furnace is 100°C, 200°C and 300°C for 1 hour each.