Complex-phase high-voltage energy storage dielectric film, capacitor and preparation method thereof

Abstract

The invention provides a complex-phase high-voltage energy storage dielectric film, a capacitor and a preparation method of the complex-phase high-voltage energy storage dielectric film, the chemical formula of the complex-phase high-voltage energy storage dielectric film material is Bi (4-x) AxTi (3-x) BxO12, A is a + 3-valent rare earth element ion, B is a + 4-valent ion, x represents the doping amount of the A ion or the B ion, x is equal to 0.5-1, and the complex-phase high-voltage energy storage dielectric film material has a part of pyrochlore phase. By forming part of the pyrochlore phase with higher dielectric constant, the energy storage density of the film material and the compression strength of the film material are improved; by accurately controlling the sintering temperature and the material composition, the dielectric loss of the thin film material is effectively reduced, and the energy conversion efficiency is improved; the P-E linetype of the thin film material is optimized, the polarization response is more uniform and stable, and the working stability and reliability of the complex-phase high-voltage energy storage dielectric capacitor can be improved; the preparation process is simple, the production cost can be reduced, the production efficiency can be improved, and the process of converting a new material from a laboratory to the market can be accelerated.

Description

Technical Field

[0001] The present invention relates to the field of ceramic materials, and in particular to a multi-phase high-voltage energy storage dielectric film, a capacitor and a preparation method thereof. Background Art

[0002] With the development of modern power electronics, the requirements for the energy storage density and compressive strength of dielectric ceramic materials are increasing. In particular, in fields such as pulsed power systems, power regulation equipment, and new energy storage technologies, dielectric ceramic materials with high energy storage density and high compressive strength have become key technical requirements.

[0003] Currently, one of the methods to improve the energy storage density and compressive strength of dielectric ceramics is to construct glass ceramics. Glass ceramics are made by mixing ceramic materials with glass phases and taking advantage of the low melting point characteristics of the glass phase to achieve sintering at a lower temperature, thereby improving the density and overall performance of the material. At the same time, because glass has an amorphous structure, it can often improve the breakdown strength. This method can effectively improve the energy storage density of the material, but it also brings some problems. The main problem is that the amorphous structure of the glass phase leads to its relatively low dielectric constant. The dielectric constant is a physical quantity that measures the ability of a material to store electrical energy. A low dielectric constant means that the material stores less electrical energy under the same electric field. In addition, the presence of the glass phase may increase the dielectric loss of the material, affecting its stability and service life under high-frequency electric fields.

[0004] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art.

[0005] In view of the above, there is an urgent need to provide a high-polarization antiferroelectric ceramic material, a capacitor and a preparation method thereof to solve the above problems. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a multiphase high-voltage energy storage dielectric film, a capacitor and a preparation method thereof, which are used to solve the problem in the prior art of improving the dielectric constant of the material and reducing dielectric loss while maintaining high energy storage density and withstand voltage strength.

[0007] To achieve the above-mentioned and other related purposes, the present invention provides a multiphase high-voltage energy storage dielectric film, the chemical formula of the multiphase high-voltage energy storage dielectric film material is Bi (4-x) A x Ti (3-x) B x O 12, wherein A is a +3-valent rare earth element ion, B is a +4-valent ion, x represents the doping amount of A ion or B ion, x=0.5~1, and the multiphase high-voltage energy storage dielectric thin film material has a partial pyrochlore phase.

[0008] Optionally, element A is any one of lanthanum, neodymium or samarium; element B is any one of zirconium, hafnium or tin.

[0009] Optionally, the multi-phase high-voltage energy storage dielectric film is grown on a single crystal substrate deposited with a metal seed layer.

[0010] Optionally, the film thickness of the multi-phase high-voltage energy storage dielectric film ranges from 300 nm to 800 nm.

[0011] The present invention also provides a method for preparing a multiphase high-voltage energy storage dielectric film, which is used to prepare any of the multiphase high-voltage energy storage dielectric films described above. The method for preparing the multiphase high-voltage energy storage dielectric film comprises:

[0012] S1: Preparation of chemical composition Bi4Ti3O 12 a first precursor solution;

[0013] S2: preparing a second precursor solution comprising source A and source B;

[0014] S3: mixing the first precursor solution and the second precursor solution and aging the mixture to form a mixed precursor solution;

[0015] S4: depositing the mixed precursor solution on a substrate to form the multi-phase high-voltage energy storage dielectric film.

[0016] Optionally, the molar concentrations of the first precursor solution and the second precursor solution are the same, and the molar concentration range is 0.1M to 0.4M.

[0017] Optionally, in step S1, the specific steps of preparing the first precursor solution include:

[0018] S11: dissolving bismuth nitrate in a solvent, heating at a temperature range of 60° C. to 150° C. for 0.5 to 3 hours, and then cooling to room temperature;

[0019] S12: Tetrabutyl titanate and a complexing agent are introduced into the bismuth nitrate solution in step S11, and the mixed solution is continuously stirred for 1 h to 3 h under ambient conditions to obtain a clear and transparent first precursor solution.

[0020] Optionally, in step S2, the specific steps of preparing the second precursor solution include:

[0021] S21: dissolving equal amounts of one source A and one source B in a solvent at a temperature range of 60° C. to 150° C. for 0.5 to 3 hours;

[0022] S22: continuously stirring the mixed solution obtained in step S21 for 1 h to 3 h to obtain a second precursor solution.

[0023] Optionally, the source A is acetic acid A or nitric acid A, and the source B is any one of tin acetate, hafnium 2,4-pentanedioate or zirconium n-propoxide.

[0024] Optionally, in step S21 , 5% to 15% excess of the B source is added to compensate for volatilization during the heat treatment process.

[0025] Optionally, in step S3, the mixed precursor solution is aged for a period of 4 to 6 days.

[0026] Optionally, in step S4, the specific steps of depositing the mixed precursor solution include:

[0027] S41: providing a single crystal substrate with a metal seed layer;

[0028] S42: Depositing the mixed precursor solution on the single crystal substrate away from the metal seed layer by spin coating, with a rotation speed ranging from 3000 rpm to 6000 rpm and a rotation time ranging from 10 s to 60 s;

[0029] S43: baking the thin film deposited in step S42, wherein the baking temperature ranges from 100° C. to 300° C., and the baking time ranges from 0.5 min to 5 min;

[0030] S44: pyrolyzing the film in step S43, wherein the pyrolysis temperature ranges from 350° C. to 500° C., and the pyrolysis time ranges from 0.5 min to 5 min;

[0031] S45: crystallizing the thin film in step S44, wherein the crystallization temperature ranges from 550° C. to 800° C., and the crystallization time ranges from 3 min to 30 min.

[0032] Optionally, in step S45, the crystallization temperature is regulated by the doping amount, T=(540+125*x)±20, where T is the crystallization temperature and x is the doping amount.

[0033] Optionally, the method for preparing the multiphase high-voltage energy storage dielectric film comprises repeating step S4 until the film thickness of the multiphase high-voltage energy storage dielectric film reaches 300 nm to 800 nm.

[0034] Optionally, the relationship between the film thickness of the multiphase high-voltage energy storage dielectric film and the molar concentration of the first precursor or the second precursor is t=c*2000, where t is the film thickness and c is the molar concentration of the first precursor or the second precursor.

[0035] The present invention also provides a multi-phase high-voltage energy storage dielectric capacitor, which includes a multi-phase high-voltage energy storage dielectric film layer and an electrode layer on its surface. The multi-phase high-voltage energy storage dielectric film layer is any one of the multi-phase high-voltage energy storage dielectric films described above.

[0036] Optionally, the electrode layer has a diameter ranging from 50 μm to 500 μm and a thickness ranging from 10 nm to 200 nm.

[0037] The present invention also provides a method for preparing a multi-phase high-voltage energy storage dielectric capacitor, the method comprising:

[0038] S5: depositing metal on the surface of the multi-phase high-voltage energy storage dielectric film through a mask with a preset shape to form the multi-phase high-voltage energy storage dielectric capacitor.

[0039] As described above, the multi-phase high-voltage energy storage dielectric film, capacitor and preparation method thereof of the present invention have the following beneficial effects:

[0040] The multiphase high-voltage energy storage dielectric film, capacitor and preparation method thereof of the present invention form a partial pyrochlore phase with a higher dielectric constant, so that the multiphase high-voltage energy storage dielectric film can store more electrical energy under the same electric field, thereby improving the energy storage density of the film material; by precisely controlling the sintering temperature and material composition, the dielectric loss of the film material is effectively reduced, and the energy conversion efficiency is improved; the introduction of the pyrochlore phase improves the compressive strength of the film material, because the pyrochlore phase has a higher breakdown field strength, so that the film material can operate at a higher voltage without breakdown; the PE linear shape of the film material is optimized, and the polarization response is more uniform and stable, which helps to improve the working stability and reliability of the multiphase high-voltage energy storage dielectric capacitor; the preparation process of the multiphase high-voltage energy storage dielectric film and capacitor is simple, which can reduce production costs, improve production efficiency, and also help to accelerate the transformation process of new materials from the laboratory to the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Shown is a schematic flow chart of the method for preparing the multi-phase high-voltage energy storage dielectric film of the present invention.

[0042] Figure 2 Shown is a schematic diagram of a specific process for preparing the first precursor solution of the present invention.

[0043] Figure 3 Shown is a schematic diagram of a specific process for preparing the second precursor solution of the present invention.

[0044] Figure 4 Shown is a schematic diagram of a specific process for preparing a mixed precursor solution of the present invention.

[0045] Figure 5 Shown is a schematic flow chart of the preparation method of the multi-phase high-voltage energy storage dielectric capacitor of the present invention.

[0046] Figure 6 Shown are the X-ray diffraction patterns of Comparative Examples 1 to 2 and Examples 1 to 3 of the present invention. DETAILED DESCRIPTION

[0047] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0048] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional views showing the device structures will not be partially enlarged according to the general scale, and the schematic views are only examples and should not limit the scope of protection of the present invention.

[0049] For ease of description, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one structure or feature shown in the drawings to other structures or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. As used herein, "between" is inclusive of both endpoints.

[0050] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where an additional feature is formed between the first and second features, such that the first and second features may not be in direct contact.

[0051] See also Figures 1 to 6It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0052] In conjunction with the questions mentioned in the background technology, how to improve the dielectric constant of the material and reduce dielectric loss while maintaining high energy storage density and compressive strength has become an important direction of research in dielectric ceramic materials. In particular, the introduction of a second phase with low loss, high breakdown field strength and relatively high dielectric constant is considered to be an effective way to solve this problem. The introduction of the second phase can be achieved in a variety of ways, such as by chemical doping, physical mixing or utilizing annealing temperature to cause it to form spontaneously. These methods can improve the dielectric properties of the material without sacrificing its compressive strength and energy storage density, thereby meeting the needs of modern power electronic equipment for high-performance dielectric ceramic materials. However, the introduction of the second phase also brings new challenges, such as compatibility issues, interface stability and the complexity of the preparation process.

[0053] Example 1

[0054] This embodiment provides a multi-phase high-voltage energy storage dielectric film. The chemical formula of the multi-phase high-voltage energy storage dielectric film material is Bi (4-x) A x Ti (3-x) B x O 12 , wherein A is a +3-valent rare earth element ion, B is a +4-valent ion, x represents the doping amount of A ion or B ion, x=0.5~1, the value of x includes the endpoint values ​​at both ends, and the multiphase high-voltage energy storage dielectric thin film material has a partial pyrochlore phase.

[0055] The dielectric constant of the pyrochlore phase is approximately 80 to 100. In this embodiment, by forming a portion of the pyrochlore phase with a higher dielectric constant, the multiphase high-voltage energy storage dielectric film can store more electrical energy under the same electric field, thereby improving the energy storage density of the film material; by precisely controlling the sintering temperature and material composition, the dielectric loss of the film material is effectively reduced and the energy conversion efficiency is improved; the introduction of the pyrochlore phase improves the compressive strength of the film material, because the pyrochlore phase has a higher breakdown field strength, allowing the film material to operate at a higher voltage without breakdown; the PE linear shape of the film material is optimized, and the polarization response is more uniform and stable.

[0056] The addition of A ions to the multiphase high-voltage energy storage dielectric film in this embodiment primarily alters the polarization direction, preventing in-plane polarization from causing weak out-of-plane signals and increasing the system's relaxivity. The addition of B ions primarily enhances relaxivity and increases the likelihood of pyrochlore phase formation. In a preferred embodiment, the A element is any one of lanthanum (La), neodymium (Nd), or samarium (Sm); and the B element is any one of zirconium (Zr), hafnium (Hf), or tin (Sn).

[0057] To facilitate the formation of a multi-phase high-voltage energy storage dielectric thin film material, in one practical example, the multi-phase high-voltage energy storage dielectric thin film is grown on a single crystal substrate deposited with a metal seed layer. Specifically, the single crystal substrate is a Pt / Si single crystal substrate, meaning that a Pt seed layer is deposited on one surface of the Si substrate, and the multi-phase high-voltage energy storage dielectric thin film is formed on the other surface.

[0058] In a specific example that can be implemented, the film thickness of the multi-phase high-voltage energy storage dielectric film ranges from 300 nm to 800 nm. The film thickness can be set according to actual needs and is not specifically limited here.

[0059] Example 2

[0060] like Figure 1 As shown, this embodiment provides a method for preparing a multiphase high-voltage energy storage dielectric film, which is used to prepare the multiphase high-voltage energy storage dielectric film described in any one of the first embodiments. The method for preparing the multiphase high-voltage energy storage dielectric film includes:

[0061] S1: Preparation of chemical composition Bi4Ti3O 12 a first precursor solution;

[0062] S2: preparing a second precursor solution comprising source A and source B;

[0063] S3: aging the first precursor solution and the second precursor solution and then mixing them to form a mixed precursor solution;

[0064] S4: depositing the mixed precursor solution on the substrate to form a multiphase high-voltage energy storage dielectric film.

[0065] The following combination Figures 1 to 4 , specifically describe the preparation method of multiphase high-voltage energy storage dielectric film.

[0066] like Figure 1 and Figure 2 As shown, in an practicable example, in step S1, the steps of preparing the first precursor solution include:

[0067] S11: dissolving bismuth nitrate (Bi(NO3)3) in a solvent, heating at a temperature range of 60°C to 150°C for 0.5h to 3h, and then cooling to room temperature;

[0068] S12: Tetrabutyl titanate (C 16 H 36 O4Ti) and a complexing agent are introduced into the bismuth nitrate solution in step S11, and the mixed solution is continuously stirred for 1 hour to 3 hours under ambient conditions to obtain a clear and transparent first precursor solution.

[0069] Specifically, bismuth nitrate (Bi(NO3)3) is heated and dissolved in a volatile solvent. The specific dissolution temperature and time can be set according to actual needs, as long as it can be dissolved in the solvent. The complexing agent in step S12 is preferably acetylacetone (C5H8O2). The specific stirring time of the mixed solution at room temperature can be set according to actual needs, as long as the mixed solution can be fully mixed and a clear and transparent first precursor solution can be obtained.

[0070] Furthermore, the molar concentration of the first precursor solution ranges from 0.1M to 0.4M.

[0071] like Figure 1 and Figure 3 As shown, in an practicable example, in step S2, the steps of preparing the second precursor solution include:

[0072] S21: dissolving equal amounts of one source A and one source B in a solvent at a temperature ranging from 60° C. to 150° C. for 0.5 h to 3 h;

[0073] S22: continuously stirring the mixed solution obtained in step S21 for 1 h to 3 h to obtain a second precursor solution.

[0074] Furthermore, the source A is acetic acid A or nitric acid A, and the source B is tin acetate, hafnium 2,4-pentanedioate or zirconium n-propoxide (C 12 H 28 The A source is any one of lanthanum (La), neodymium (Nd) or samarium (Sm). Preferably, the A source can be any one of lanthanum acetate, neodymium acetate, samarium acetate, lanthanum nitrate, neodymium nitrate, and samarium nitrate.

[0075] The molar concentration of the second precursor solution ranges from 0.1M to 0.4M. It should be noted that the molar concentration of the second precursor solution should be the same as the molar concentration of the first precursor solution.

[0076] Furthermore, in step S21, 5% to 15% excess B source is added to compensate for volatilization during the heat treatment process, that is, to avoid poor pyrochlore phase formation due to lack of B source in the subsequently formed multi-phase high-voltage energy storage dielectric film.

[0077] In a specific example that can be implemented, in step S3, the aging time of the mixed precursor solution ranges from 4 days to 6 days, so that the two precursor solutions are fully mixed and reacted to obtain the preset required mixed precursor solution.

[0078] like Figure 1 and Figure 4 As shown, in an implementable specific example, in step S4, the specific steps of depositing the mixed precursor solution include:

[0079] S41: providing a single crystal substrate with a metal seed layer;

[0080] S42: using a spin coating method, depositing the mixed precursor solution on the single crystal substrate away from the metal seed layer, with a rotation speed ranging from 3000 rpm to 6000 rpm and a rotation time ranging from 10 s to 60 s;

[0081] S43: baking the thin film deposited in step S42, with the baking temperature ranging from 100° C. to 300° C. and the baking time ranging from 0.5 min to 5 min;

[0082] S44: Pyrolyzing the film in step S43 at a temperature ranging from 350° C. to 500° C. for a time ranging from 0.5 min to 5 min;

[0083] S45: crystallizing the thin film in step S44, with a crystallization temperature ranging from 550° C. to 800° C. and a crystallization time ranging from 3 min to 30 min.

[0084] It should be noted that the specific deposition parameters, temperature ranges and time ranges for baking, pyrolysis and crystallization can be set according to actual conditions and are not limited here.

[0085] Furthermore, in step S45, the crystallization temperature can be controlled by the doping amount, T = (540 + 125 * x) ± 20, where T is the crystallization temperature and x is the doping amount. The higher the doping amount x, the higher the required crystallization temperature.

[0086] In a specific example that can be implemented, a method for preparing a multiphase high-voltage energy storage dielectric film is as follows: step S4 is repeated until the film thickness of the multiphase high-voltage energy storage dielectric film reaches 300nm to 800nm, that is, the preset required thickness of the multiphase high-voltage energy storage dielectric film.

[0087] Preferably, when the precursor solution is spin-coated multiple times by spin coating, step S43 is first performed to complete baking after each layer is spin-coated, and then step S44 is performed to complete pyrolysis. After all layers are spin-coated, step S44 is performed to complete crystallization.

[0088] Furthermore, the relationship between the film thickness of the multiphase high-voltage energy storage dielectric film and the molar concentration of the first precursor or the second precursor is t=c*2000, where t is the film thickness and c is the molar concentration of the first precursor or the second precursor.

[0089] Example 3

[0090] This embodiment provides a multi-phase high-voltage energy storage dielectric capacitor, which includes a multi-phase high-voltage energy storage dielectric film layer and an electrode layer on its surface. The multi-phase high-voltage energy storage dielectric film layer is the multi-phase high-voltage energy storage dielectric film described in any one of the first embodiments.

[0091] Furthermore, the electrode layer has a diameter ranging from 50 to 500 μm and a thickness ranging from 10 to 200 nm.

[0092] It should be noted that the metal type of the electrode layer must be the same as the metal seed type on the single crystal substrate. In this embodiment, the electrode layer is a platinum (Pt) layer, located on a Si substrate away from the Pt / Si single crystal substrate and the multi-phase high-voltage energy storage dielectric film. The specific parameters of the electrode layer can be set according to actual needs and are not limited here.

[0093] Example 4

[0094] like Figure 5 As shown, this embodiment provides a method for preparing a multi-phase high-voltage energy storage dielectric capacitor, and the method for preparing the multi-phase high-voltage energy storage dielectric capacitor includes:

[0095] Step S5: depositing metal on the surface of the multi-phase high-voltage energy storage dielectric film in the first embodiment through a mask with a preset shape to form a multi-phase high-voltage energy storage dielectric capacitor.

[0096] Because the PE linear shape of the film material is optimized, the polarization response is more uniform and stable, which significantly improves the working stability and reliability of the multi-phase high-voltage energy storage dielectric capacitor; the preparation process of the multi-phase high-voltage energy storage dielectric film and capacitor is simple, which can reduce production costs, improve production efficiency, and also help accelerate the transformation of new materials from the laboratory to the market.

[0097] Comparative experiment

[0098] In order to specifically illustrate the performance of the capacitor prepared by this method, two groups of comparative examples and three groups of examples are listed below for specific description.

[0099] Comparative Example 1: Based on Bi4Ti3O 12 Film capacitors

[0100] A certain amount of bismuth nitrate (Bi(NO3)3) was dissolved in a solvent, heated at 120°C for 2 hours, and then cooled to room temperature to obtain a Bi(NO3)3 solution. 16 H 36 O4Ti) and acetylacetone (C5H8O2) were introduced into Bi(NO3)3 solution, and the mixed solution was stirred for 2 h under ambient conditions to obtain clear and transparent Bi4Ti3O 12 solution, its molar concentration is 0.3M.

[0101] Bi4Ti3O 12 The solution was spin-coated on a Pt / Si single crystal substrate until the film thickness reached 600 nm to obtain Bi4Ti3O 12 film.

[0102] Finally, metal Pt was deposited on Bi4Ti3O 12 On the surface of the film, an electrode layer with a diameter of 400 μm and a thickness of 180 nm was formed, and finally a Bi4Ti3O 12 Film capacitors.

[0103] Comparative Example 2: Capacitor based on Bi2Ti2O7 film

[0104] A certain amount of bismuth nitrate (Bi(NO3)3) was dissolved in a solvent, heated at 120°C for 2 hours, and then cooled to room temperature to obtain a Bi(NO3)3 solution. 16 H 36 O4Ti) and acetylacetone (C5H8O2) were introduced into Bi(NO3)3 solution, and the mixed solution was stirred for 2 h under ambient conditions to obtain clear and transparent Bi4Ti3O 12 solution, its molar concentration is 0.3M.

[0105] Bi4Ti3O 12 After the solution was aged for five days, Bi4Ti3O 12 The solution was spin-coated onto a Pt / Si single crystal substrate until the film thickness reached 600nm. Each layer was baked at 200°C for 3 minutes, then pyrolyzed at 450°C for 3 minutes. After all layers were spin-coated, they were crystallized at 560°C for 20 minutes to obtain the Bi2Ti2O7 thin film.

[0106] Finally, metal Pt was deposited on the surface of the Bi2Ti2O7 film to form an electrode layer with a diameter of 400μm and a thickness of 180nm, and finally a capacitor based on the Bi2Ti2O7 film was obtained.

[0107] Example 1: Based on Bi 3.5 La 0.5 Ti 2.5 Hf 0.5 O 12 Film capacitors

[0108] A certain amount of bismuth nitrate (Bi(NO3)3) was dissolved in a solvent, heated at 120°C for 2 hours, and then cooled to room temperature to obtain a Bi(NO3)3 solution. 16 H 36 O4Ti) and acetylacetone (C5H8O2) were introduced into the Bi(NO3)3 solution, and the mixed solution was continuously stirred for 2 hours under ambient conditions to obtain a clear and transparent first precursor solution with a molar concentration of 0.3M.

[0109] A fixed amount of lanthanum acetate (lanthanum nitrate) and an excess of 10% hafnium 2,4-pentanedioate were dissolved in a solvent at a temperature of 120° C. for 2 hours. The resulting mixed solution was stirred for 2 hours to prepare a second precursor solution having the same molar concentration of 0.3 M.

[0110] The first precursor solution and the second precursor solution are mixed and aged for 5 days to form a mixed precursor solution.

[0111] The precursor solution was spin-coated on the Pt / Si single crystal substrate multiple times at a rotation speed of 5000 r / min and a rotation time of 40s until the film thickness reached 600nm. After each layer was spin-coated, it was baked at 200℃ for 3min and then pyrolyzed at 450℃ for 3min. After all layers were spin-coated, they were crystallized at 622.5℃ for 20min to obtain Bi 3.5 La 0.5 Ti 2.5 Hf 0.5 O 12 film.

[0112] Finally, metal Pt is deposited on Bi 3.5 La 0.5 Ti 2.5 Hf 0.5 O 12 On the surface of the film, an electrode layer with a diameter of 400 μm and a thickness of 180 nm is formed, and finally a Bi-based 3.5 La 0.5 Ti 2.5 Hf 0.5 O12 Film capacitors.

[0113] Example 2: Based on Bi3NdTi2ZrO 12 Film capacitors

[0114] A certain amount of bismuth nitrate (Bi(NO3)3) was dissolved in a solvent, heated at 120°C for 2 hours, and then cooled to room temperature to obtain a Bi(NO3)3 solution. 16 H 36 O4Ti) and acetylacetone (C5H8O2) were introduced into the Bi(NO3)3 solution, and the mixed solution was continuously stirred for 2 hours under ambient conditions to obtain a clear and transparent first precursor solution with a molar concentration of 0.3M.

[0115] A certain amount of neodymium acetate (neodymium nitrate) and an excess of 10% zirconium n-propoxide were dissolved in a solvent at a temperature of 120° C. for 2 hours. The resulting mixed solution was stirred for 2 hours to prepare a second precursor solution having the same molar concentration of 0.3 M.

[0116] The first precursor solution and the second precursor solution are mixed and aged for 5 days to form a mixed precursor solution.

[0117] The mixed precursor solution was spin-coated on the Pt / Si single crystal substrate multiple times at a rotation speed of 5000 r / min and a rotation time of 40 s until the film thickness reached 600 nm. After each layer was spin-coated, it was baked at 200 ° C for 3 minutes and then pyrolyzed at 450 ° C for 3 minutes. After all layers were spin-coated, they were crystallized at 685 ° C for 20 minutes to obtain Bi3NdTi2ZrO 12 film.

[0118] Finally, metal Pt was deposited on Bi3NdTi2ZrO 12 On the surface of the film, an electrode layer with a diameter of 400 μm and a thickness of 180 nm was formed, and finally a Bi3NdTi2ZrO 12 Film capacitors.

[0119] Example 3: Based on Bi 3.25 Sm 0.75 Ti 2.25 Sn 0.75 O 12 Film capacitors

[0120] A certain amount of bismuth nitrate (Bi(NO3)3) was dissolved in a solvent, heated at 120°C for 2 hours, and then cooled to room temperature to obtain a Bi(NO3)3 solution. 16 H 36O4Ti) and acetylacetone (C5H8O2) were introduced into the Bi(NO3)3 solution, and the mixed solution was continuously stirred for 2 hours under ambient conditions to obtain a clear and transparent first precursor solution with a molar concentration of 0.3M.

[0121] A fixed amount of samarium acetate (samarium nitrate) and an excess of 10% tin acetate were dissolved in a solvent at a temperature of 120° C. for 2 hours. The resulting mixed solution was stirred for 2 hours to prepare a second precursor solution having the same molar concentration of 0.3 M.

[0122] The first precursor solution and the second precursor solution are mixed and aged for 5 days to form a mixed precursor solution.

[0123] The mixed precursor solution was spin-coated on the Pt / Si single crystal substrate multiple times at a rotation speed of 5000 r / min and a rotation time of 40s until the film thickness reached 600nm. After each layer was spin-coated, it was baked at 200℃ for 3min and then pyrolyzed at 450℃ for 3min. After all layers were spin-coated, they were crystallized at 653.75℃ for 20min to obtain Bi 3.25 Sm 0.75 Ti 2.25 Sn 0.75 O 12 film.

[0124] Finally, metal Pt is deposited on Bi 3.25 Sm 0.75 Ti 2.25 Sn 0.75 O 12 On the surface of the film, an electrode layer with a diameter of 400 μm and a thickness of 180 nm is formed, and finally a Bi-based 3.25 Sm 0.75 Ti 2.25 Sn 0.75 O 12 Film capacitors.

[0125] The capacitor bank obtained from the above experiment was tested and the 2000kV cm -1 The polarization value is obtained by continuously increasing the electric field of the hysteresis loop until breakdown occurs, obtaining the breakdown electric field. The energy storage density is obtained by integrating the polarization through the hysteresis loop. The average specific parameters shown in Table 1 below can be obtained.

[0126] Table 1 Comparative experimental parameters of comparative examples and embodiments

[0127]

[0128]

[0129] From the parameter values ​​in Table 1, it can be seen that the breakdown electric field of the multi-phase high-voltage energy storage dielectric capacitor of the embodiment increases first and then decreases with the increase of the doping amount x, and reaches the maximum value of 5125kVcm when x=0.75. -1 , are greater than the single-phase Bi4Ti3O 12 The thin film capacitor has a high breakdown electric field, which allows the capacitor to remain stable under high electric fields and is less likely to experience dielectric breakdown, thereby ensuring the reliability and safety of the capacitor. The polarization value of the multi-phase high-voltage energy storage dielectric capacitor of the embodiment decreases with increasing doping amount x, but also retains a relatively high polarization value, thereby ensuring the energy storage density. The energy storage density of the multi-phase high-voltage energy storage dielectric capacitor of the embodiment increases first and then decreases with increasing doping amount x, reaching a maximum of 125 J / cm at x = 0.75. -3 , are greater than the single-phase Bi4Ti3O 12 Thin film capacitors and capacitors based on Bi2Ti2O7 thin films enable multiphase high-voltage energy storage dielectric capacitors to store more electrical energy in a smaller volume or mass, which is beneficial to improving the energy density and energy storage efficiency of the capacitor.

[0130] like Figure 6 The X-ray diffraction patterns of Comparative Examples 1-2 and Examples 1-3 are shown. It can be seen from the figure that both Comparative Example 2 and Examples 1-3 contain a pyrochlore phase. Combined with the experimental parameters in Table 1, the introduction of the pyrochlore phase improves the compressive strength of the film material (capacitor). Because the pyrochlore phase has a higher breakdown field strength, the film material (capacitor) can operate at a higher voltage without breakdown. The dielectric constant is also relatively high, and the dielectric loss is relatively small. The PE line shape of the film material (capacitor) is optimized, and the polarization response is more uniform and stable, which helps to improve the operating stability and reliability of the multi-phase high-voltage energy storage dielectric capacitor.

[0131] In summary, this embodiment provides a multi-phase high-voltage energy storage dielectric film, a capacitor and a preparation method thereof. The chemical formula of the multi-phase high-voltage energy storage dielectric film material is Bi (4-x) A x Ti (3-x) B x O 12, where A is a +3 valence rare earth element ion, B is a +4 valence ion, x represents the doping amount of A ion or B ion, and x = 0.5 to 1. The composite high-voltage energy storage dielectric film material has a partial pyrochlore phase. This embodiment forms a partial pyrochlore phase with a higher dielectric constant, so that the composite high-voltage energy storage dielectric film can store more electrical energy under the same electric field, thereby improving the energy storage density of the film material; by precisely controlling the sintering temperature and material composition, the dielectric loss of the film material is effectively reduced, and the energy conversion efficiency is improved; the introduction of the pyrochlore phase improves the compressive strength of the film material, because the pyrochlore phase has a higher breakdown field strength, allowing the film material to operate at higher voltages without breakdown; the PE linear shape of the film material is optimized, and the polarization response is more uniform and stable, which helps to improve the working stability and reliability of the composite high-voltage energy storage dielectric capacitor; the preparation process of the composite high-voltage energy storage dielectric film and capacitor is simple, which can reduce production costs, improve production efficiency, and also help to accelerate the transformation process of new materials from the laboratory to the market. Therefore, the present invention effectively overcomes the various shortcomings of the existing technology and has high industrial utilization value.

[0132] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A multiphase high-voltage energy storage dielectric film, characterized in that: The chemical formula of the multiphase high-voltage energy storage dielectric film material is Bi (4-x) A x Ti (3-x) B x O 12 , wherein A is a +3-valent rare earth element ion, B is a +4-valent ion, x represents the doping amount of A ion or B ion, x=0.5~1, and the multiphase high-voltage energy storage dielectric thin film material has a partial pyrochlore phase.

2. The multiphase high-voltage energy storage dielectric film according to claim 1, characterized in that: Element A is any one of lanthanum, neodymium or samarium; element B is any one of zirconium, hafnium or tin.

3. The multiphase high-voltage energy storage dielectric film according to claim 1, characterized in that: The multi-phase high-voltage energy storage dielectric film is grown on a single crystal substrate deposited with a metal seed layer.

4. The multiphase high-voltage energy storage dielectric film according to claim 1, characterized in that: The film thickness of the multi-phase high-voltage energy storage dielectric film ranges from 300 nm to 800 nm.

5. A method for preparing a multiphase high-voltage energy storage dielectric film, for preparing the multiphase high-voltage energy storage dielectric film according to any one of claims 1 to 4, characterized in that: The method for preparing the multiphase high-voltage energy storage dielectric film comprises: S1: Preparation of chemical composition Bi4Ti3O 12 a first precursor solution; S2: preparing a second precursor solution comprising source A and source B; S3: mixing the first precursor solution and the second precursor solution and aging the mixture to form a mixed precursor solution; S4: depositing the mixed precursor solution on a substrate to form the multi-phase high-voltage energy storage dielectric film.

6. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 5, characterized in that: The molar concentrations of the first precursor solution and the second precursor solution are the same, and the molar concentration range is 0.1M to 0.4M.

7. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 5, characterized in that: In step S1, the specific steps of preparing the first precursor solution include: S11: dissolving bismuth nitrate in a solvent, heating at a temperature range of 60° C. to 150° C. for 0.5 to 3 hours, and then cooling to room temperature; S12: Tetrabutyl titanate and a complexing agent are introduced into the bismuth nitrate solution in step S11, and the mixed solution is continuously stirred for 1 h to 3 h under ambient conditions to obtain a clear and transparent first precursor solution.

8. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 5, characterized in that: In step S2, the specific steps of preparing the second precursor solution include: S21: dissolving equal amounts of one source A and one source B in a solvent at a temperature range of 60° C. to 150° C. for 0.5 to 3 hours; S22: continuously stirring the mixed solution obtained in step S21 for 1 h to 3 h to obtain a second precursor solution.

9. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 8, characterized in that: The A source is acetic acid A or nitric acid A, and the B source is any one of tin acetate, hafnium 2,4-pentanedioate or zirconium n-propoxide.

10. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 8, characterized in that: In step S21 , 5% to 15% excess of the B source is added to compensate for volatilization during the heat treatment process.

11. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 5, characterized in that: In step S3, the mixed precursor solution is aged for 4 to 6 days.

12. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 5, characterized in that: In step S4, the specific steps of depositing the mixed precursor solution include: S41: providing a single crystal substrate with a metal seed layer; S42: Depositing the mixed precursor solution on the single crystal substrate away from the metal seed layer by spin coating, with a rotation speed ranging from 3000 rpm to 6000 rpm and a rotation time ranging from 10 s to 60 s; S43: baking the thin film deposited in step S42, wherein the baking temperature ranges from 100° C. to 300° C., and the baking time ranges from 0.5 min to 5 min; S44: pyrolyzing the film in step S43, wherein the pyrolysis temperature ranges from 350° C. to 500° C., and the pyrolysis time ranges from 0.5 min to 5 min; S45: crystallizing the thin film in step S44, wherein the crystallization temperature ranges from 550° C. to 800° C., and the crystallization time ranges from 3 min to 30 min.

13. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 12, characterized in that: In step S45, the crystallization temperature is regulated by the doping amount, T=(540+125*x)±20, where T is the crystallization temperature and x is the doping amount.

14. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 5, characterized in that: The method for preparing the multi-phase high-voltage energy storage dielectric film comprises repeating step S4 until the film thickness of the multi-phase high-voltage energy storage dielectric film reaches 300 nm to 800 nm.

15. The method for preparing a multiphase high-voltage energy storage dielectric film according to claim 5, characterized in that: The relationship between the film thickness of the multiphase high-voltage energy storage dielectric film and the molar concentration of the first precursor or the second precursor is t=c*2000, where t is the film thickness and c is the molar concentration of the first precursor or the second precursor.

16. A multiphase high-voltage energy storage dielectric capacitor, characterized in that: The multiphase high-voltage energy storage dielectric capacitor comprises a multiphase high-voltage energy storage dielectric film layer and an electrode layer on its surface. The multiphase high-voltage energy storage dielectric film layer is the multiphase high-voltage energy storage dielectric film according to any one of claims 1 to 4.

17. The multi-phase high-voltage energy storage dielectric capacitor according to claim 16, characterized in that: The electrode layer has a diameter ranging from 50 μm to 500 μm and a thickness ranging from 10 nm to 200 nm.

18. A method for preparing a multi-phase high-voltage energy storage dielectric capacitor, characterized in that: The preparation method of the multi-phase high-voltage energy storage dielectric capacitor comprises: S5: depositing metal on the surface of the multi-phase high-voltage energy storage dielectric film through a mask with a preset shape to form the multi-phase high-voltage energy storage dielectric capacitor.

Images