Preparation method of polycrystalline, micron-thick barium titanate ceramic film with folding lossless performance and film

Abstract

The present invention relates to the technical field of piezoelectric films, and specifically to a method for preparing a polycrystalline, micron-thick barium titanate ceramic film with fold-free lossless properties and the film itself. First, a barium titanate precursor sol is prepared, in which the weight percentage of the barium source is 9 wt% to 12 wt%; then, the sol is electrospun onto a spinning template with a topological structure to obtain a barium titanate precursor film with a spinning thickness of 3μm to 10μm; finally, the film is calcined at a temperature range of 600°C to 650°C for 8 hours to obtain a barium titanate ceramic film. This application ensures smooth spinning by adjusting the weight percentage of the barium source and adjusting the spinning thickness to achieve micron-thick spinning. The applicant found that the film has self-supporting properties within the spinning thickness range of 3μm to 10μm, and the topological structure spinning template can give the film superelasticity and fold-free lossless properties. Finally, the film is ensured to have good flexibility and piezoelectric properties by setting the calcination parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric films, and in particular to a preparation method and film of a polycrystalline barium titanate ceramic film with micron-level thickness and fold-lossless performance. Background Art

[0002] Piezoelectric films have attracted considerable attention due to their excellent electromechanical effect, which generates surface charges when subjected to mechanical stress. Given this property, if piezoelectric films could be made flexible, stretchable, wearable, and portable, they could be used to fabricate intelligent devices with unique functions when subjected to applied mechanical forces, such as bending and stretching. These devices include piezoelectric tactile sensors, piezoelectric nanogenerators (PENGs), wearable or implantable devices (such as antibacterial scaffolds for bone regeneration), and mechanical energy harvesters. The development of flexible piezoelectric films is particularly valuable for potential innovative applications in municipal engineering, such as directional droplet transport, hydromechanical energy generators, and novel catalytic degradation of pollutants.

[0003] Barium titanate ceramic films are currently a hot topic of research due to their excellent piezoelectric properties. However, existing technologies have not been able to produce polycrystalline, micron-thick, superelastic, and fold-proof barium titanate ceramic films. Polycrystalline, micron-thick, superelastic, and fold-proof barium titanate ceramic films offer broader application prospects. Summary of the Invention

[0004] In order to solve the technical problem that it is impossible to produce a barium titanate ceramic film that is polycrystalline, micron-sized, superelastic, and has fold-proof properties in the prior art, the present invention provides a method for preparing a polycrystalline, micron-sized, and fold-proof barium titanate ceramic film and a barium titanate ceramic film by improving the preparation process and process parameters. The details are as follows:

[0005] In a first aspect, the present invention provides a method for preparing a barium titanate ceramic film, the method comprising the following steps:

[0006] S100, preparing a barium titanate precursor sol: dissolving 9 wt% to 12 wt% of a barium source, a titanium source, and a thickening cross-linking agent in a solvent, and stirring to obtain a barium titanate precursor sol;

[0007] S200, electrospinning the barium titanate precursor sol: electrospinning the barium titanate precursor sol onto a spinning template with a topological structure, with a spinning thickness of 3 μm to 10 μm, to obtain a barium titanate precursor film;

[0008] S300, calcining the barium titanate precursor film to obtain a barium titanate ceramic film: the calcination temperature is maintained in the range of 600° C. to 650° C., and the calcination time is 8 hours.

[0009] Furthermore, in step S300, the temperature is raised from room temperature to 600°C-650°C at a heating rate of 2°C / min in an air atmosphere and maintained in this temperature range for calcination for 8 hours, and then the temperature is lowered to room temperature at a cooling rate of 5°C / min.

[0010] Furthermore, in step S100, first, the thickening cross-linking agent is dissolved in the solvent at 25° C. and stirred until dissolved; then, the barium source is added while stirring and continued to be stirred until dissolved; then, the titanium source is added dropwise while stirring; finally, the solution is continued to be stirred to obtain a barium titanate precursor sol.

[0011] Furthermore, in step S200 , the positive voltage of the electrospinning is +16 kV, the negative voltage is −4 kV, and the injection speed of the barium titanate precursor sol is 0.75 ml / h.

[0012] Furthermore, in step S100 , after the barium titanate precursor sol is prepared, ultrasonic treatment is performed on the sol.

[0013] Furthermore, the molar ratio of the barium source to the titanium source in the barium titanate precursor sol obtained in step S100 is 1:1.

[0014] Furthermore, the barium source is barium acetate, and the titanium source is tetrabutyl titanate.

[0015] Furthermore, in step S100, the solvent includes acetic acid, ethanol and deionized water, and the mass ratio of acetic acid, ethanol and deionized water is 4:5:1.

[0016] Furthermore, in step S100, the thickening cross-linking agent is polyvinyl pyrrolidone, and its weight percentage is 5 wt%.

[0017] In a second aspect, the present application provides a barium titanate ceramic film, which is prepared by the above-mentioned preparation method of the barium titanate ceramic film.

[0018] The beneficial effects of the present invention are as follows: the preparation method provided by the present application includes three steps: the first step is to prepare a barium titanate precursor sol, in which the weight percentage of the barium source is 9 wt%~12 wt%; the second step is to electrospin the sol onto a spinning template with a topological structure and the spinning thickness is 3μm~10μm to obtain a barium titanate precursor film; the third step is to calcine the barium titanate precursor film at a temperature range of 600℃~650℃ for 8h to obtain a barium titanate ceramic film. The present application ensures the smooth spinning by adjusting the weight percentage of the barium source, and realizes large-scale spinning, i.e., micron-level spinning, by coordinating the spinning thickness. The applicant found that the barium titanate ceramic film prepared with a spinning thickness in the range of 3μm~10μm is self-supporting, and the topological structure spinning template can give the film superelasticity and fold-proof properties. Finally, the film is ensured to have good flexibility and piezoelectric properties by setting the calcination parameters. Experiments have shown that the barium titanate ceramic film prepared by this application has the properties of large scale, polycrystalline, superelasticity and no damage when folded, and no creases are produced after being folded hundreds of times. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the method of this application;

[0020] Figure 2 This is an expanded image of a barium titanate ceramic film with an inner thickness of 3 μm and an outer thickness of 20 μm, with a gradient thickness change from the inner side to the outer side;

[0021] Figure 3 yes Figure 2 The morphology of the film after being folded along the dotted line;

[0022] Figure 4 (a) is a SEM image of the first barium titanate ceramic film;

[0023] Figure 4 (b) is a TEM image of the first barium titanate ceramic film;

[0024] Figure 4 (c) is the SAED spectrum of the first barium titanate ceramic film;

[0025] Figure 4 (d) is the HRTEM spectrum of the first barium titanate ceramic film;

[0026] FIG4( e ) is a diagram showing the bending angle of the first barium titanate ceramic film;

[0027] FIG4( f ) is a graph showing the piezoelectric properties of the first barium titanate ceramic film;

[0028] Figure 5 (a) is a SEM image of the second barium titanate ceramic film;

[0029] Figure 5(b) is a TEM image of the second barium titanate ceramic film;

[0030] Figure 5 (c) is the SAED spectrum of the second barium titanate ceramic film;

[0031] Figure 5 (d) is the HRTEM spectrum of the second barium titanate ceramic film;

[0032] FIG5( e ) is a diagram showing the bending angle of the second barium titanate ceramic film;

[0033] FIG5( f ) is a graph showing the piezoelectric properties of the second barium titanate ceramic film;

[0034] Figure 6 (a) is a SEM image of the third barium titanate ceramic film;

[0035] Figure 6(b) is the TEM spectrum of the third barium titanate ceramic film;

[0036] Figure 6 (c) is the SAED spectrum of the third barium titanate ceramic film;

[0037] Figure 6 (d) is the HRTEM spectrum of the third barium titanate ceramic film;

[0038] FIG6 (e) is a bending angle diagram of the third barium titanate ceramic film;

[0039] FIG6( f ) is a graph showing the piezoelectric properties of the third barium titanate ceramic film;

[0040] Figure 7 (a) is a SEM image of the fourth barium titanate ceramic film;

[0041] Figure 7(b) is a TEM image of the fourth barium titanate ceramic film;

[0042] Figure 7 (c) is the SAED spectrum of the fourth barium titanate ceramic film;

[0043] Figure 7 (d) is the HRTEM spectrum of the fourth barium titanate ceramic film;

[0044] FIG7( e ) is a diagram showing the bending angle of the fourth barium titanate ceramic film;

[0045] FIG7( f ) is a graph showing the piezoelectric properties of the fourth barium titanate ceramic film;

[0046] Figure 8 is the XRD comparison diagram of the first, second, third and fourth barium titanate ceramic films;

[0047] Figure 9 This is the morphology of the second type of barium titanate ceramic film in the prior art after being folded 180° 20 times;

[0048] Figure 10 This is the morphology of the third barium titanate ceramic film after being folded 180° 200 times. DETAILED DESCRIPTION

[0049] The following further describes the specific embodiments of the present invention in conjunction with the accompanying drawings to provide a deeper understanding of the concept of the present invention, the technical problems solved, the technical features constituting the technical solutions, and the technical effects brought about. However, it should be noted that the description of these embodiments is illustrative only and does not constitute a specific limitation of the present invention.

[0050] In order to facilitate understanding of the inventive concept of this application, it is now introduced as follows:

[0051] Piezoelectric film is a thin film that generates an electrical charge on its surface when subjected to mechanical stress. This property makes it suitable for applications such as pressure sensors, piezoelectric nanogenerators, wearable devices, implantable devices, and mechanical energy harvesting. Since piezoelectric film only generates an electrical charge when subjected to mechanical stress, making it more flexible is crucial.

[0052] In the prior art, materials for piezoelectric films usually include piezoelectric organic polymers, piezoelectric ceramics, or composite materials composed of a blend of piezoelectric organic polymers and piezoelectric ceramics. Among them, piezoelectric organic polymers have flexibility and processability, such as polyvinylidene fluoride (PVDF) and polyamide 11 (PA-11), but their piezoelectric coefficient, electron mobility, and electromechanical coupling constant are low. Composite materials composed of a blend of piezoelectric organic polymers and piezoelectric ceramics are an effective way to improve piezoelectric and dielectric properties, but poor dispersibility between the two components, interface pore defects, and cracks will limit the piezoelectric performance. In comparison, pure phase piezoelectric ceramics have the best piezoelectric properties, but pure phase piezoelectric ceramics are hard and brittle, which limits their application. Therefore, how to improve the high elasticity and high flexibility of piezoelectric ceramics is a technical problem that needs to be solved at present. In order to solve this technical problem, there are the following two methods in the prior art:

[0053] Approach 1: Utilizing low-dimensional nanostructures, such as 1D nanowires or nanorods and 2D nanoplates and / or nanosheets, promises to address the brittleness of piezoelectric ceramics. On the one hand, the vibrational energies of Ti-O, Zr-O, and Si-O bonds in inorganic crystals are much lower than those of C-C, C-O, and C-H bonds in organic polymers. As the diameter of inorganic crystals decreases from micrometers to nanometers, scale effects impart unique mechanical properties to the material. For example, diamond nanoneedles avoid internal defects, enhance smoothness, and exhibit exceptionally large elastic deformation. Similarly, as the diameter of one-dimensional structures like fibers decreases from micrometers to nanometers, the resulting size reduction imparts unique mechanical, thermal, and electrical properties to nanofibers. Studies have shown that further reduction in size at the nanoscale leads to a shift from hard and brittle (greater than 100 nanometers) to elastic and flexible (a few nanometers). On the other hand, the ionic or covalent bonds in ceramics possess significantly greater interaction strength than those in shape memory alloys, but lack sufficient slip systems, leading to dislocation motion under deformation and brittle fracture. The phase transition of low-dimensional nanoceramics provides tolerance for atomic displacement in the coexisting phase, triggering additional strain that exceeds the elastic limit of the crystalline material and has the ability to recover. In addition, due to the limited size of nanomaterials, the specific surface area is higher than that of bulk materials, and the defect density is significantly reduced. The reason is that grain boundaries, dislocations and defects lead to the brittleness of ceramics. Therefore, reducing defects can avoid stress concentration and inhibit the formation of cracks inside ceramics. Studies have shown that the use of piezoelectric zinc oxide nanowire (NW) arrays to convert nanoscale mechanical energy into electrical energy can achieve mutual conversion between thin films and nanowires, but due to the limitations of material form, the application range of nanowires is very limited.

[0054] The second approach, using single-crystal thin films to enhance the flexibility of piezoelectric ceramics, is currently employed by most research, and has already successfully produced superelastic and ultraflexible ferroelectric films. Single-crystal thin films significantly enhance the performance of piezoelectric ceramics, but because most ferroelectric materials, such as barium titanate, are polycrystalline, this approach lacks widespread applicability. Furthermore, as the thickness of single-crystal thin films increases, achieving a small radius of curvature becomes difficult.

[0055] Both of the above methods have limitations when used and cannot produce micron-thick barium titanate ceramic films that are polycrystalline, superelastic, and fold-lossless.

[0056] To this end, this application provides a method for preparing a barium titanate ceramic thin film, comprising three steps: preparing a barium titanate precursor sol, spinning, and calcining. This method involves spinning the sol onto a topologically structured spinning template and adjusting parameters such as the weight percentage of the titanium source, spinning thickness, and calcining temperature to produce a micron-thick barium titanate ceramic film that exhibits the excellent properties of polycrystalline, superelasticity, and fold-proof properties.

[0057] Please combine Figure 1 As shown, the steps of this method are detailed as follows:

[0058] Step S100: First, prepare a barium titanate precursor sol: dissolve 9wt% to 12wt% of a barium source, a titanium source, and a thickening crosslinking agent in a solvent and stir to obtain a barium titanate precursor sol. In one embodiment of the present application, first, dissolve the thickening crosslinking agent in the solvent at 25°C and stir until dissolved; then, add the barium source while stirring and continue stirring until dissolved; then, add the titanium source dropwise while stirring; finally, continue stirring the solution until it reaches a certain viscosity to obtain a barium titanate precursor sol.

[0059] The barium titanate precursor sol includes a barium source, a titanium source and a thickening cross-linking agent.

[0060] The barium source can be selected from one or more of barium carbonate, barium acetate, barium sulfate, barium nitrate, barium chloride, barium hydroxide, and barium oxide. The titanium source can be selected from one or more of titanium dioxide colloid, titanium trichloride, titanium tetrachloride, titanium oxysulfate, titanium acetylacetonate, isopropyl titanate, tetrabutyl titanate, and tetraethyl titanate. The thickening and bonding agent can be selected from one or more of polyvinyl alcohol, polyvinylidene fluoride, polyethylene oxide, polyvinyl acetate, polyvinyl butyral, and polyvinyl pyrrolidone. In one embodiment of the present application, the barium source is barium acetate, the titanium source is tetrabutyl titanate, and the thickening and bonding agent is polyvinyl pyrrolidone, and its weight percentage is 5 wt%.

[0061] Optional solvents include acetic acid-ethanol-deionized water solvent system, acetic acid-DMF-deionized water solvent system, acetic acid-DMF-acetylacetone, etc. In one embodiment of the present application, an acetic acid-ethanol-deionized water solvent system is selected, and the mass ratio of acetic acid, ethanol, and deionized water is 4:5:1.

[0062] If the weight percentage of the barium source is too low, it is not suitable for spinning treatment. If it is too high, it will make solution preparation difficult. The weight percentage of the barium source in this application is in the range of 9wt%~12wt%, which is conducive to solution preparation and suitable for spinning treatment.

[0063] Preferably, after the barium titanate precursor sol is prepared, the isotitanate precursor sol is subjected to ultrasonic treatment to make the system components of the sol more uniformly dispersed and more conducive to spinning. The ultrasonic treatment time is 0.5 h.

[0064] In order to ensure that the barium source and the titanium source react completely, it is preferred that the molar ratio of the barium source to the titanium source in the barium titanate precursor sol is 1:1.

[0065] Step S200, electrospinning the barium titanate precursor sol: electrospinning the barium titanate precursor sol onto a spinning template with a topological structure, with a spinning thickness of 3μm~10μm, to obtain a barium titanate precursor film. Specifically, a layer of silicone oil paper is covered on the spinning template with a topological structure, and the spinning is carried out on the silicone oil paper. The spinning template is used to influence the density of the spinning, and the barium titanate ceramic film with a topological structure obtained by calcination has better flexibility, superelasticity and fold-proof properties. The topological structure can be a circular topological structure, a square topological structure, a honeycomb topological structure, a trident topological structure, a square-trident combination topological structure, etc. The positive voltage during the electrospinning process is +16 kV, the negative voltage is -4kV, and the injection rate of the barium titanate precursor sol is 0.75ml / h.

[0066] During the experiment, the inventors found that for a micron-thick barium titanate ceramic film with a thickness between 3μm and 10μm, it can easily maintain a uniform arc, has self-supporting properties, and will not become unstable and crease. Figure 2 As shown in the figure, the thickness of the barium titanate ceramic film is 3μm on the inside and 20μm on the outside, and the thickness changes gradually from the inside to the outside. Figure 3 As shown, the inner 3μm can easily maintain a uniform arc, while when the outer 20μm is folded, creases will appear due to instability, and finally a sharp angle shape will appear. Judging from the overall bending situation, the critical position where instability and creases occur is in the middle 10μm. Therefore, the spinning thickness of this application is 3μm~10μm to ensure that the final prepared barium titanate ceramic film can maintain a uniform arc when bent and has self-supporting properties.

[0067] In step S300, the barium titanate precursor film is calcined to obtain a barium titanate ceramic film. The calcination temperature is maintained in the range of 600°C to 650°C for 8 hours. Specifically, in one embodiment of the present application, the temperature is increased from room temperature to 600°C to 650°C at a heating rate of 2°C / min in an air atmosphere and maintained in this temperature range for 8 hours. The temperature is then cooled to room temperature at a cooling rate of 5°C / min.

[0068] The inventors analyzed the wires in the barium titanate ceramic film as beams and obtained the structural flexibility equation based on the beam strain equation, maximum strain equation, elastic modulus equation and Hall-Page relationship. , where d is the grain size, D is the wire diameter, ρ is the curvature of the wire, and K is a specific constant. From this equation, it can be seen that the grain size d and the wire diameter D are the key factors affecting the flexibility of polycrystalline piezoelectric ceramics. The smaller the grain size, the better the flexibility. The better the crystallization of the barium titanate ceramic film, the better the piezoelectric performance, but the lower the flexibility of the piezoelectric film. The calcination temperature and time are key factors affecting the grain size d and filament diameter D. The applicant has found that calcining for 8 hours at a temperature between 600°C and 650°C can make the grains relatively dense but not too large, resulting in a piezoelectric film that achieves both piezoelectric performance and flexibility. This is illustrated below with experimental data:

[0069] This application conducted four control experiments. First, four identical barium titanate precursor films were prepared using steps S100 and S200 of this application. The barium source was barium acetate, the titanium source was tetrabutyl titanate; the thickening crosslinker was polyvinyl pyrrolidone, with a weight percentage of 5 wt%; the solvents included acetic acid, ethanol, and deionized water in a mass ratio of 4:5:1; the positive voltage for electrospinning was +16 kV, the negative voltage was -4 kV, the injection rate of the barium titanate precursor sol was 0.75 ml / h, and the injection and receiving distance was 21 cm; after the barium titanate precursor sol was prepared, the sol was ultrasonically treated for 0.5 h; the molar ratio of the barium source to the titanium source in the barium titanate precursor sol was 1:1; and the spinning template used was a circular topology spinning template.

[0070] Next, four identical barium titanate precursor films were calcined at 550°C, 600°C, 620°C, and 650°C for 8 hours, respectively, to obtain the first barium titanate ceramic film BTO-1 calcined at 550°C for 8 hours, the second barium titanate ceramic film BTO-2 calcined at 600°C for 8 hours, the third piezoelectric film BTO-3 calcined at 620°C for 8 hours, and the fourth piezoelectric film BTO-4 calcined at 650°C for 8 hours. During the calcination, the temperature was increased from room temperature at a heating rate of 2°C / min in an air atmosphere, and then cooled to room temperature at a cooling rate of 5°C / min after calcination for 8 hours.

[0071] The SEM image of the first barium titanate ceramic film BTO-1 is shown in Figure 4(a), the TEM image is shown in Figure 4(b), the SAED pattern is shown in Figure 4(c), the HRTEM pattern is shown in Figure 4(d), the bending angle diagram is shown in Figure 4(e), and the piezoelectric performance is shown in Figure 4(f). As shown in Figures 4(a), 4(b), 4(c), 4(d), 4(e), and 4(f), the grains of the first barium titanate ceramic film obtained by calcining at 550°C for 8 hours are very small and inconspicuous. The grains are almost invisible in the TEM image. The grain size is calculated to be 9nm using the Scherrer formula. Although it is flexible and can be bent 180°, its piezoelectric performance is the worst.

[0072] The SEM image of the second barium titanate ceramic film BTO-2 is shown in Figure 5(a), the TEM image is shown in Figure 5(b), the SAED pattern is shown in Figure 5(c), the HRTEM pattern is shown in Figure 5(d), the bending angle diagram is shown in Figure 5(e), and the piezoelectric performance is shown in Figure 5(f). As shown in Figures 5(a), 5(b), 5(c), 5(d), 5(e), and 5(f), the second barium titanate ceramic film obtained by calcining at 600°C for 8 hours has finely dispersed grains. The grain size is calculated to be 10 nm according to the Scherrer formula. Although it is flexible and can be bent at 61°, its piezoelectric performance is poor.

[0073] The SEM image of the third barium titanate ceramic film BTO-3 is shown in Figure 6(a), the TEM image is shown in Figure 6(b), the SAED pattern is shown in Figure 6(c), the HRTEM pattern is shown in Figure 6(d), the bending angle diagram is shown in Figure 6(e), and the piezoelectric properties are shown in Figure 6(f). As shown in Figures 6(a), 6(b), 6(c), 6(d), 6(e), and 6(f), the third barium titanate ceramic film obtained by calcining at 620°C for 8 hours has large and dense grains with a grain size of 30nm, good flexibility, can be bent at 43°, and has good piezoelectric properties.

[0074] The SEM image of the fourth barium titanate ceramic film BTO-4 is shown in Figure 7(a), the TEM image is shown in Figure 7(b), the SAED pattern is shown in Figure 7(c), the HRTEM pattern is shown in Figure 7(d), the bending angle diagram is shown in Figure 7(e), and the piezoelectric performance is shown in Figure 7(f). As shown in Figures 7(a), 7(b), 7(c), 7(d), 7(e), and 7(f), the fourth barium titanate ceramic film calcined at 650°C for 8 hours has full and dense grains with a grain size of 50nm. Its flexibility is poor and can only be bent at 32°, but its piezoelectric performance is the best.

[0075] The morphology and flexibility comparison table of the first to fourth barium titanate ceramic films is shown below:

[0076] serial number Calcination parameters Grain d (nm) Wire diameter D (nm) Dd3 / 2 Bending angle Flexibility Crystallinity The first barium titanate ceramic thin film Calcination at 550°C for 8h ~9 ~200 5400 180° most Sparse and hard to see Second barium titanate ceramic film Calcination at 600°C for 8h ~13 ~180 8437 61° better Small and scattered The third barium titanate ceramic film Calcination at 620°C for 8h ~30 ~160 26291 43° Fair Large and dense Fourth barium titanate ceramic film Calcination at 650°C for 8h ~50 ~150 53033 32° Worst Full and dense

[0077] The XRD comparison diagrams of the above four types of barium titanate ceramic films are as follows: Figure 8 As shown. Figure 8 It can be seen that the first barium titanate ceramic film is mainly composed of barium carbonate (BCO) with a small amount of BTO, and the BTO crystallization is poor. However, as the calcination temperature increases, the second and third barium titanate ceramic films successively show better BTO crystallization. The characteristic peak of the barium titanate ceramic film reaches its highest peak in the fourth barium titanate ceramic film, which also has the lowest BCO content. The BCO peak of the third barium titanate ceramic film is slightly more prominent than that of the fourth barium titanate ceramic film, but it also shows good BTO crystallization.

[0078] Figure 9 The morphology of the third barium titanate ceramic film in this application after being folded 180° 200 times is shown. Figure 10 The morphology of the random-morphology barium titanate ceramic film prepared by conventional spinning is shown after being folded 180° 20 times. Figure 9 and Figure 10 It can be seen that the barium titanate ceramic film prepared by conventional spinning showed creases and cracks after being folded 20 times, while the barium titanate ceramic film prepared by the present application still had no creases even after being folded 200 times, and even remained macroscopically traceless after being folded 400 times, showing excellent flexibility, and it bounced back to its original position after each folding and unloading of force, demonstrating super elastic performance.

[0079] The present application also provides a barium titanate ceramic film, which is prepared by the above method.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a polycrystalline, micron-thick barium titanate ceramic film with fold-proof lossless performance, characterized in that: The steps include: S100, preparing a barium titanate precursor sol: dissolving 9 wt % to 12 wt % of a barium source, a titanium source, and a thickening cross-linking agent in a solvent, and stirring to obtain a barium titanate precursor sol; S200, electrospinning the barium titanate precursor sol: electrospinning the barium titanate precursor sol onto a spinning template with a topological structure, with a spinning thickness of 3 μm to 10 μm, to obtain a barium titanate precursor film; The electrostatic spinning of the barium titanate precursor sol onto a spinning template having a topological structure refers to covering the spinning template with a layer of silicone oil paper and spinning on the silicone oil paper; S300, calcining the barium titanate precursor film to obtain a barium titanate ceramic film: the calcination temperature is maintained in the range of 620° C., and the calcination time is 8 hours.

2. The preparation method according to claim 1, wherein: In step S300 , the temperature is raised from room temperature to 620° C. at a heating rate of 2° C. / min in an air atmosphere and maintained in this temperature range for calcination for 8 hours, and then the temperature is lowered to room temperature at a cooling rate of 5° C. / min.

3. The preparation method according to claim 1, wherein: In step S100, first, a thickening crosslinking agent is dissolved in a solvent at 25°C and stirred until dissolved; then, a barium source is added while stirring and continued to be stirred until dissolved; then, a titanium source is added dropwise while stirring; finally, the solution is continued to be stirred to obtain a barium titanate precursor sol.

4. The preparation method according to claim 1, wherein: In step S200 , the positive voltage of electrospinning is +16 kV, the negative voltage is −4 kV, and the injection speed of the barium titanate precursor sol is 0.75 ml / h.

5. The method for preparing a barium titanate ceramic film according to any one of claims 1 to 4, characterized in that: In step S100, after the barium titanate precursor sol is prepared, ultrasonic treatment is performed for 0.5 h.

6. The preparation method according to any one of claims 1 to 4, characterized in that: The molar ratio of the barium source to the titanium source in the barium titanate precursor sol obtained in step S100 is 1:

1.

7. The preparation method according to any one of claims 1 to 4, characterized in that: The barium source is barium acetate, and the titanium source is tetrabutyl titanate.

8. The preparation method according to any one of claims 1 to 4, characterized in that: In step S100 , the solvent includes acetic acid, ethanol, and deionized water, and the mass ratio of acetic acid, ethanol, and deionized water is 4:5:

1.

9. The preparation method according to claim 1, wherein: In step S100, the thickening cross-linking agent is polyvinyl pyrrolidone, and its weight percentage is 5 wt%.

10. Barium titanate ceramic film, characterized in that: The barium titanate ceramic film is prepared by the preparation method according to any one of claims 1 to 9.

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