A sodium niobate-based lead-free ceramic dielectric material, a preparation method and application thereof

Abstract

The application relates to a sodium niobate-based lead-free ceramic dielectric material and a preparation method and application thereof, the chemical composition of the material is (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)‑xCaHfO3+0.01‑0.2wt%MnCO3, wherein x=0‑0.08, and the preparation method comprises the following steps: S1, selecting raw materials; S2, uniformly ball-milling; S3, calcining; S4, adding MnCO3 and secondarily ball-milling, and then drying, screening, S5, uniformly mixing with an organic solvent, an emulsifier, a plasticizer, a binder and a dispersant; S6, preparing a ceramic film through a flow casting process, and then carrying out isostatic pressing treatment; S7, carrying out glue removal treatment and heat preservation, and then sintering to obtain the sodium niobate-based ceramic dielectric material. Compared with the prior art, the application has the advantages of high breakdown electric field strength, slender hysteresis loop, excellent energy storage characteristics, and great practical value for realizing lead-free, miniaturization and integration of electronic components.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dielectric materials, and particularly relates to a sodium niobate-based lead-free ceramic dielectric material and a preparation method and application thereof. BACKGROUND

[0002] Energy is the material basis for the survival and development of human society. With the comprehensive development of social modernization, its demand is increasing day by day, and how to efficiently use energy has become the focus of attention of countries all over the world. The high-speed development of electronic components miniaturization and integration puts forward higher requirements for the performance of materials. Ceramic dielectric capacitors are widely used in important fields such as aerospace, medical devices, automotive electronics, and laser weapons due to their fast charge and discharge speed, high power density, long cycle life, wide use temperature range, and good safety. Lead-based antiferromagnetic materials occupy a dominant position in the ceramic dielectric capacitor market due to their excellent energy storage characteristics and discharge characteristics, but the harm of lead elements to the environment and health makes the development of environmentally friendly lead-free dielectric energy storage materials imminent.

[0003] Barium titanate, sodium bismuth titanate, strontium titanate, potassium sodium niobate, silver niobate, and sodium niobate are the main research categories of lead-free energy storage ceramic systems. Among them, sodium niobate-based ceramics, as an important member of lead-free antiferromagnetic systems, have the characteristics of small theoretical density, high polarization strength and Curie temperature, and rich phase structure, and have attracted widespread attention in the field of dielectric energy storage. However, the antiferromagnetic phase of sodium niobate-based ceramics is easily transformed into a metastable ferroelectric phase under the induction of a high electric field, thereby exhibiting a square saturation electric hysteresis loop with ferroelectric characteristics, resulting in large leakage and loss at high fields, which makes it difficult to obtain a high breakdown field and is not conducive to obtaining high energy storage density. Therefore, various methods have been used to reduce the leakage and loss of sodium niobate-based ceramics and further improve their energy storage density. Patent (application number CN202211407274) dopes an appropriate amount of Ba(Fe 0.5 Nb 0.5 )O3 into the NaNbO3 matrix to obtain an energy storage density of 0.97~4 J / cm 3 at room temperature, and the energy storage efficiency is 55.8~82.4%. So far, the energy storage density and energy storage efficiency of sodium niobate-based lead-free energy storage ceramics are 5 J / cm 3 and below 85%, respectively, and it is difficult to simultaneously obtain sodium niobate-based ceramics with high energy storage density, high energy storage efficiency, and low loss, which limits the application of this system in the field of dielectric energy storage. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a sodium niobate-based lead-free ceramic dielectric material and a preparation method and application thereof.

[0005] The material can significantly improve the energy storage density and energy storage efficiency of lead-free energy storage ceramics, and its breakdown field. The ceramic obtained by the application has high breakdown field strength, excellent energy storage characteristics, simple preparation process, good ceramic sample uniformity, high reliability, lead-free and pollution-free, which is conducive to promoting the development needs of the next generation of electronic components.

[0006] The object of the application can be achieved by the following technical solutions:

[0007] The application first introduces a certain amount of CaHfO3 component into the NaNbO3-Sr 0.7 Bi 0.2 TiO3 binary system, and adds an appropriate amount of MnCO3 to reduce the leakage of the prepared NaNbO3-Sr 0.7 Bi 0.2 TiO3-CaHfO3 material, thereby improving its insulation. While maintaining the high saturation polarization strength of sodium niobate, the leakage is significantly reduced, the remanent polarization is reduced, and the breakdown field strength is improved, so that the energy storage density of the sodium niobate-based lead-free ceramic medium is greatly improved, which has great practical application value.

[0008] The first aspect of the application provides a sodium niobate-based lead-free ceramic medium material, and the chemical composition of the ceramic medium material is (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)-xCaHfO3+0.01-0.2wt%MnCO3, wherein x=0-0.08.

[0009] As a preferred mode of the application, the mass fraction of MnCO3 is 0.1%.

[0010] The second aspect of the application provides a preparation method of a sodium niobate-based lead-free ceramic medium material, comprising the following steps:

[0011] S1: selecting Bi2O3, SrCO3, CaCO3, HfO2, TiO2, Na2CO3, Nb2O5 and MnCO3 as raw materials;

[0012] S2: according to the stoichiometric ratio of (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)-xCaHfO3 and uniformly mixed by one-time ball milling, wherein x=0-0.08;

[0013] S3: calcining the raw materials of the ingredients in S2 to obtain a pre-synthesized ceramic powder;

[0014] S4: adding MnCO3 to the pre-synthesized ceramic powder obtained in S3 and secondary ball milling, and then drying and sieving through a 200-mesh screen to obtain the raw material powder of the sodium niobate-based lead-free ceramic dielectric material;

[0015] It should be noted that the drying in S4 is a common operation in the art, such as drying at 100°C.

[0016] S5: adding an organic solvent, an emulsifier, a plasticizer, a binder and a dispersant to the raw material powder of the sodium niobate-based lead-free ceramic dielectric material obtained in S4 and mixing uniformly to obtain a slurry of the sodium niobate-based lead-free ceramic dielectric material;

[0017] S6: preparing a ceramic film of the corresponding components by a tape casting process from the slurry of the sodium niobate-based lead-free ceramic dielectric material obtained in S5, and then cutting and performing isostatic pressing to obtain a green body of the sodium niobate-based lead-free ceramic dielectric material;

[0018] It should be noted that the tape casting process in S6 is a common operation in the art.

[0019] S7: performing degreasing treatment and heat preservation on the green body of the sodium niobate-based ceramic dielectric material obtained in S6, and then sintering to obtain the sodium niobate-based ceramic dielectric material.

[0020] Further, in S2, S4 and S5, the specific conditions of the primary ball milling are as follows: using anhydrous ethanol and ZrO2 balls as the ball milling medium, the mass ratio of ZrO2 balls, anhydrous ethanol and the raw material is (2.5-3.0):(1.2-1.5):1, the ball milling speed is 400-450 r / min, and the ball milling time is 12-15 h.

[0021] The specific conditions of the secondary ball milling are as follows: using anhydrous ethanol and ZrO2 balls as the ball milling medium, the mass ratio of ZrO2 balls, anhydrous ethanol and the raw material is (2.5-3.0):(1.2-1.5):1, the ball milling speed is 400-450 r / min, and the ball milling time is 12-15 h.

[0022] As a preferred mode of the present application, the specific conditions of the primary ball milling are as follows: using anhydrous ethanol and ZrO2 balls as the ball milling medium, the mass ratio of ZrO2 balls, anhydrous ethanol and the raw material is 3.0:1.2:1, the ball milling speed is 400 r / min, and the ball milling time is 12 h.

[0023] The specific conditions of the secondary ball milling are as follows: using anhydrous ethanol and ZrO2 balls as the ball milling medium, the mass ratio of ZrO2 balls, anhydrous ethanol and the raw material is 3.0:1.5:1, the ball milling speed is 400 r / min, and the ball milling time is 12 h.

[0024] Further, in S3, the specific conditions of calcination are: 700-950℃ calcination for 3-8h under a closed condition.

[0025] As a preferred mode of the present application, in S3, the specific conditions of calcination are: 800-850℃ calcination for 4-6h under a closed condition, more preferably, 850℃ calcination for 4h under a closed condition.

[0026] Further, in S4, the amount of MnCO3 added is 0.01-0.2% of the sum of the mass of the raw materials after batching in S2 and the amount of MnCO3.

[0027] As a preferred mode of the present application, in S4, the amount of MnCO3 added is 0.1wt% of the raw materials after batching in S2.

[0028] Further, in S5, the organic solvent is a mixture of anhydrous ethanol and butanone, wherein the amount of anhydrous ethanol added is 45-60% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material, and the amount of butanone added is 90-110% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0029] The emulsifier is glyceryl trioleate, and the amount of glyceryl trioleate added is 2.5-3.5% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0030] The plasticizer is dibutyl phthalate, and the amount of dibutyl phthalate added is 2.5-3.5% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0031] The binder is polyvinyl butyral, and the amount of polyvinyl butyral added is 8-14% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0032] The dispersant is polyethylene glycol, and the amount of polyethylene glycol added is 2.5-3.5% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0033] As a preferred mode of the present application, in S5, the amount of anhydrous ethanol added is 50% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material, and the amount of butanone added is 90% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0034] The amount of glyceryl trioleate added is 3% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0035] The amount of dibutyl phthalate added is 3% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0036] The adding amount of the polyvinyl butyral is 9.5% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material;

[0037] The adding amount of the polyethylene glycol is 3% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material.

[0038] Further, in S6, the specific conditions of the isostatic pressing treatment are: temperature 50-100℃, and the pressing pressures are 50 MPa, 100 MPa, 150 MPa and 200 MPa respectively.

[0039] As a preferred mode of the present application, in S6, the specific conditions of the isostatic pressing treatment are: temperature 75℃, and the pressing pressures are 50 MPa, 100 MPa, 150 MPa and 200 MPa respectively.

[0040] Further, in S7, the glue removal treatment is carried out at 500-700℃, and the holding time is 6-12h.

[0041] As a preferred mode of the present application, in S7, the glue removal treatment is carried out at 550-600℃, and the holding time is 8-12h, and more preferably, the glue removal treatment is carried out at 600℃, and the holding time is 12h.

[0042] Further, in S7, the sintering conditions are: under a closed condition, the temperature is raised from room temperature to 1000-1350℃ at a temperature raising rate of 3-4℃ / min and is held for 1-4h, and then is naturally cooled to room temperature along with the furnace.

[0043] As a preferred mode of the present application, in S7, the sintering conditions are: under a closed condition, the temperature is raised from room temperature to 1200-1270℃ at a temperature raising rate of 3-4℃ / min and is held for 2-3h, and then is naturally cooled to room temperature along with the furnace, and more preferably, under a closed condition, the temperature is raised from room temperature to 1250℃ at a temperature raising rate of 4℃ / min and is held for 2h.

[0044] The third aspect of the present application provides an application of the sodium niobate-based lead-free ceramic dielectric material, which is used as an energy storage material in the fields of laser, radar, mobile communication or aerospace.

[0045] Compared with the prior art, the present application has the following beneficial effects:

[0046] (1) The sodium niobate-based lead-free ceramic dielectric material prepared by the present application has high breakdown field strength, slender hysteresis loop and excellent energy storage characteristics, and has great practical value for realizing the lead-free, miniaturization and integration of electronic components.

[0047] (2) The present application can improve the energy storage characteristics of the sodium niobate-based lead-free ceramic dielectric material by adding the polyvinyl butyral, the polyethylene glycol or the polyvinyl alcohol. 0.7 Bi0.2 Introducing a certain amount of CaHfO3 into the TiO3 binary system and adding an appropriate amount of MnCO3 to reduce the yield of the prepared NaNbO3-Sr 0.7 Bi 0.2 The TiO3-CaHfO3 material exhibits improved leakage conductivity, thereby enhancing its insulation. While maintaining the high saturation polarization of sodium niobate, it significantly reduces leakage conductivity, decreases residual polarization, and increases the breakdown electric field, resulting in a substantial increase in the energy storage density of sodium niobate-based lead-free ceramic dielectrics. Furthermore, the sodium niobate-based lead-free high energy storage density and efficiency ceramic prepared in this invention utilizes a tape casting process that facilitates large-scale industrial production. This is of great significance for replacing lead-based energy storage ceramic dielectrics and is expected to find widespread application in numerous fields such as lasers, radar, mobile communications, and aerospace. Attached Figure Description

[0048] Figure 1 The hysteresis loop is the sodium niobate-based lead-free ceramic dielectric material prepared in Example 1.

[0049] Figure 2 The hysteresis loop is the sodium niobate-based lead-free ceramic dielectric material prepared in Example 2.

[0050] Figure 3 The hysteresis loop is the sodium niobate-based lead-free ceramic dielectric material prepared in Example 3.

[0051] Figure 4 The hysteresis loop is shown for the sodium niobate-based lead-free ceramic dielectric material prepared in Example 4.

[0052] Figure 5 The hysteresis loop is shown for the sodium niobate-based lead-free ceramic dielectric material prepared in Example 5.

[0053] Figure 6 The energy storage characteristics (total energy storage density W) of the sodium niobate-based lead-free ceramic dielectric material prepared in Example 1 are shown. tot The available energy storage density W rec Energy loss density W loss The curves showing the variation of energy storage efficiency η with electric field intensity.

[0054] Figure 7 The energy storage characteristics (total energy storage density W) of the sodium niobate-based lead-free ceramic dielectric material prepared in Example 2 are shown. tot The available energy storage density W rec Energy loss density W loss The curves showing the variation of energy storage efficiency η with electric field intensity.

[0055] Figure 8 The energy storage characteristics (total energy storage density W) of the sodium niobate-based lead-free ceramic dielectric material prepared in Example 3 are shown.tot the available energy storage density W rec the energy loss density W loss and the energy storage efficiency η) as a function of the electric field intensity.

[0056] Figure 9 The energy storage properties (total energy storage density W tot the available energy storage density W rec the energy loss density W loss and the energy storage efficiency η) as a function of the electric field intensity for the sodium niobate-based lead-free ceramic dielectric material prepared in Example 4.

[0057] Figure 10 The energy storage properties (total energy storage density W tot the available energy storage density W rec the energy loss density W loss and the energy storage efficiency η) as a function of the electric field intensity for the sodium niobate-based lead-free ceramic dielectric material prepared in Example 5. DETAILED DESCRIPTION

[0058] The present application will be described in detail below with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical solution of the present application, and gives a detailed implementation method and specific operation process, but the protection scope of the present application is not limited to the following examples.

[0059] Example 1

[0060] The present embodiment provides a sodium niobate-based lead-free ceramic dielectric material and a preparation method thereof, wherein the ceramic chemical composition is (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)-xCaHfO3+0.1wt%MnCO3, wherein x = 0.

[0061] The specific preparation method is as follows:

[0062] (1) Select Bi2O3, SrCO3, CaCO3, HfO2, TiO2, Na2CO3, Nb2O5 and MnCO3 with a purity greater than 98% as raw materials for the sodium niobate-based lead-free ceramic dielectric material;

[0063] (2) According to the chemical formula (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2TiO3)-xCaHfO3 (wherein x = 0) are weighed and mixed uniformly by a primary ball milling process to obtain the initial raw material powder; wherein ZrO2 balls and anhydrous ethanol are used as the ball milling medium, the mass ratio of ZrO2 balls to the raw material is 3:1, the mass ratio of anhydrous ethanol to the raw material is 1.2:1, the rotation speed of the ball mill is 400 r / min, and the ball milling time is 12 h.

[0064] (3) The dried raw material powder is calcined at 850°C for 4 h under a sealed condition to obtain a pre-synthesized ceramic powder;

[0065] (4) 0.1 wt% MnCO3 is added to the pre-synthesized ceramic powder and secondary ball milling is performed, and the slurry after ball milling is dried at 100°C; wherein ZrO2 balls and anhydrous ethanol are used as the ball milling medium, the mass ratio of ZrO2 balls to the raw material is 3.0:1, the mass ratio of anhydrous ethanol to the raw material is 1.5:1, the rotation speed of the ball mill is 400 r / min, and the ball milling time is 12 h;

[0066] (5) The raw material powder after drying in step (4) is sieved through a 200-mesh sieve to obtain the raw material powder of the sodium niobate-based lead-free ceramic dielectric material;

[0067] (6) The obtained raw material powder is mixed with an organic solvent, an emulsifier, a plasticizer, a binder and a dispersant to obtain a slurry of the sodium niobate-based lead-free ceramic dielectric material. The organic solvent is a mixture of anhydrous ethanol and butanone; the emulsifier is glyceryl trioleate; the plasticizer is dibutyl phthalate; the binder is polyvinyl butyral; and the dispersant is polyethylene glycol. The amount of anhydrous ethanol added is 50% of the mass of the raw material powder; the amount of butanone added is 90% of the mass of the raw material powder; the amount of glyceryl trioleate added is 3% of the mass of the raw material powder; the amount of polyvinyl butyral added is 9.5% of the mass of the raw material powder; the amount of polyethylene glycol added is 3% of the mass of the raw material powder; and the amount of dibutyl phthalate added is 3% of the mass of the raw material powder;

[0068] (7) The obtained ceramic slurry is prepared into a ceramic film through a tape casting process, and then cut into a square piece of 10 mm x 10 mm, and then pressed at 75°C with a pressure of 50 MPa, 100 MPa, 150 MPa and 200 MPa in sequence to obtain a green body of the sodium niobate-based lead-free ceramic dielectric material;

[0069] (8) The obtained ceramic green body is subjected to a degassing treatment at 600°C for 12 h, and then the degassed ceramic green body is heated to 1250°C at a heating rate of 4°C / min under a sealed condition and held for 2 h, and finally cooled to room temperature in the furnace to obtain the sodium niobate-based lead-free ceramic dielectric material.

[0070] The obtained sodium niobate-based lead-free ceramic dielectric material is plated with gold electrode on both sides by ion sputtering method, and the electric hysteresis loop of the material is tested at room temperature and 10 Hz by using a ferroelectric test system (Precision Premier II, USA), and the energy storage characteristics can be calculated by the following formula:

[0071] (1)

[0072] (2)

[0073] (3)

[0074] In the formula, Wtot represents the total energy storage density, Wrec represents the releasable energy density, and Wloss represents the energy loss density. P is the polarization strength, P max is the maximum polarization strength, and P r is the remanent polarization strength. Figure 1 The electric hysteresis loop of the sodium niobate-based lead-free ceramic dielectric material prepared in Example 1 is measured at room temperature and 10 Hz. As can be seen from the figure, the electric hysteresis loop of the sodium niobate-based lead-free ceramic dielectric material prepared in the application is slender, the breakdown electric field strength is high, and the maximum electric field strength can reach 650 kV / cm. The energy storage characteristics (total energy storage density W tot , available energy storage density W rec , energy loss density W loss and energy storage efficiency η) calculated based on the electric hysteresis loop under different electric field strengths change with the electric field strength curve as Figure 6 shown. As can be seen from the figure, W tot and W rec increase rapidly with the increase of the electric field strength, and W loss increases slowly with the increase of the electric field strength. In the electric field strength range of 95-650 kV / cm, η is stable at about 75%. When the electric field strength reaches 650 kV / cm, W tot = 9.45 J / cm 3 , W rec = 7.88 J / cm 3 , W loss = 1.57 J / cm 3 , and the corresponding η is 83.39%.

[0075] Example 2

[0076] The present embodiment provides a sodium niobate-based lead-free ceramic dielectric material and a preparation method thereof, wherein the chemical composition of the ceramic is (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2TiO3)-xCaHfO3+0.1wt%MnCO3, where x = 0.02. The specific preparation steps are as follows:

[0077] (1) Select Bi2O3, SrCO3, CaCO3, HfO2, TiO2, Na2CO3, Nb2O5 and MnCO3 with a purity greater than 98% as raw materials for sodium niobate-based lead-free ceramic dielectric materials;

[0078] (2) According to the chemical formula (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 The raw materials (TiO3)-xCaHfO3 (where x = 0.02) were weighed and mixed uniformly through a single ball milling process to obtain the initial raw material powder. During ball milling, anhydrous ethanol and ZrO2 balls were used as the ball milling media. The mass ratio of ZrO2 balls to raw materials was 3:1, and the mass ratio of anhydrous ethanol to raw materials was 1.2:1. The ball mill speed was 400 r / min, and the ball milling time was 12 h.

[0079] (3) The dried raw material powder was calcined at 850°C for 4 hours under sealed conditions to obtain pre-synthesized ceramic powder;

[0080] (4) Add 0.1 wt% MnCO3 to the pre-synthesized ceramic powder and perform secondary ball milling. Dry the slurry after ball milling at 100℃. During ball milling, anhydrous ethanol and ZrO2 balls are used as the ball milling media. The mass ratio of ZrO2 balls to raw materials is 3.0:1, the mass ratio of anhydrous ethanol to raw materials is 1.5:1, the speed of the ball mill is 400 r / min, and the ball milling time is 12h.

[0081] (5) Pass the dried raw material powder from step (4) through a 200-mesh sieve to obtain the raw material powder for sodium niobate-based lead-free ceramic media material;

[0082] (6) The obtained raw material powder is mixed evenly with organic solvent, emulsifier, plasticizer, binder and dispersant to obtain a slurry of sodium niobate-based lead-free ceramic dielectric material. The organic solvent is a mixture of anhydrous ethanol and methyl ethyl ketone (MEK); the emulsifier is triolein; the plasticizer is dibutyl phthalate; the binder is polyvinyl butyral; and the dispersant is polyethylene glycol. The amount of anhydrous ethanol added is 50% of the raw material powder mass; the amount of MEK added is 90% of the raw material powder mass; the amount of triolein added is 3% of the raw material powder mass; the amount of polyvinyl butyral added is 9.5% of the raw material powder mass; the amount of polyethylene glycol added is 3% of the raw material powder mass; and the amount of dibutyl phthalate added is 3% of the raw material powder mass.

[0083] (7) The obtained ceramic slurry is prepared into a ceramic membrane by a tape casting process, and then cut into a square piece of 10 mm x 10 mm, and then pressed at 75℃ by using pressures of 50 MPa, 100 MPa, 150 MPa and 200 MPa in sequence to obtain a sodium niobate-based lead-free ceramic green body;

[0084] (8) The obtained ceramic green body is subjected to a degassing treatment at 600℃ for 12 h, and then the degassed ceramic green body is heated to 1270℃ at a heating rate of 3℃ / min under a closed condition and kept for 2 h, and finally cooled to room temperature in the furnace to obtain a sodium niobate-based lead-free ceramic dielectric material.

[0085] The obtained sodium niobate-based lead-free ceramic dielectric material is plated with a gold electrode by an ion sputtering method, and an electric hysteresis loop of the material is tested at room temperature and 10 Hz by using a ferroelectric test system (Precision Premier II, USA), and the energy storage characteristics can be calculated by the following formula:

[0086] (1)

[0087] (2)

[0088] (3)

[0089] In the formula, W tot represents the total energy storage density, W rec represents the releasable energy density, W loss represents the energy loss density. P is the polarization strength, P max is the maximum polarization strength, P r is the remanent polarization strength. Figure 2 The electric hysteresis loop of the sodium niobate-based lead-free high-energy storage density and energy storage efficiency ceramic prepared in Example 2 is measured at room temperature and 10 Hz. As can be seen from the figure, the electric hysteresis loop of the sodium niobate-based ceramic dielectric material prepared in the application is slender, the breakdown electric field strength is high, and the maximum electric field strength can reach 800 kV / cm. The energy storage characteristics (total energy storage density W tot , available energy storage density W rec , energy loss density W loss and energy storage efficiency η) calculated based on the electric hysteresis loop under different electric field strengths change with the electric field strength as shown in Figure 7 . As can be seen from the figure, W tot and W rec increase rapidly with the increase of the electric field strength, and W lossthen increases slowly with the increase of the electric field intensity. In the electric field intensity range of 100-800 kV / cm, η is stable around 80%. When the electric field intensity reaches 800 kV / cm, W tot = 8.88 J / cm 3 , W rec = 7.37 J / cm 3 , W loss = 1.52 J / cm 3 , and the corresponding η is 82.94%.

[0090] Example 3

[0091] The present example provides a sodium niobate-based lead-free ceramic dielectric material and a preparation method thereof, wherein the chemical composition of the ceramic is (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)-xCaHfO3+0.1 wt% MnCO3, wherein x = 0.04. The specific preparation steps are as follows:

[0092] (1) Select Bi2O3, SrCO3, CaCO3, HfO2, TiO2, Na2CO3, Nb2O5 and MnCO3 with a purity greater than 98% as raw materials for the sodium niobate-based lead-free ceramic dielectric material;

[0093] (2) Weigh the raw materials according to the chemical formula (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)-xCaHfO3 (wherein x = 0.04), and mix them uniformly through a one-time ball milling process to obtain the initial raw material powder; wherein anhydrous ethanol and ZrO2 balls are used as the ball milling medium during ball milling, the mass ratio of ZrO2 balls to raw materials is 3:1, the mass ratio of anhydrous ethanol to raw materials is 1.2:1, the rotation speed of the ball mill is 400 r / min, and the ball milling time is 12 h.

[0094] (3) The dried raw material powder is calcined at 850°C for 4 h under airtight conditions to obtain a pre-synthesized ceramic powder;

[0095] (4) Add 0.1 wt% MnCO3 to the pre-synthesized ceramic powder and perform secondary ball milling, and dry the slurry after ball milling at 100°C; wherein anhydrous ethanol and ZrO2 balls are used as the ball milling medium during ball milling, the mass ratio of ZrO2 balls to raw materials is 3.0:1, the mass ratio of anhydrous ethanol to raw materials is 1.5:1, the rotation speed of the ball mill is 400 r / min, and the ball milling time is 12 h;

[0096] (5) The raw material powder after drying in step (4) is passed through a 200 mesh sieve to obtain a raw material powder of the sodium niobate-based lead-free high energy storage density and energy storage efficiency ceramic dielectric material;

[0097] (6) The obtained raw material powder is mixed with an organic solvent, an emulsifier, a plasticizer, a binder and a dispersant to obtain a slurry of the sodium niobate-based lead-free ceramic dielectric material. The organic solvent is a mixture of anhydrous ethanol and butanone; the emulsifier is glyceryl trioleate; the plasticizer is dibutyl phthalate; the binder is polyvinyl butyral; and the dispersant is polyethylene glycol. The anhydrous ethanol is added in an amount of 50% of the mass of the raw material powder; the butanone is added in an amount of 90% of the mass of the raw material powder; the glyceryl trioleate is added in an amount of 3% of the mass of the raw material powder; the polyvinyl butyral is added in an amount of 9.5% of the mass of the raw material powder; the polyethylene glycol is added in an amount of 3% of the mass of the raw material powder; and the dibutyl phthalate is added in an amount of 3% of the mass of the raw material powder;

[0098] (7) The obtained ceramic slurry is prepared into a ceramic film by a tape casting process, and then cut into a square piece of 10 mm x 10 mm, and then pressed at a pressure of 50 MPa, 100 MPa, 150 MPa and 200 MPa in turn at 75°C to obtain a sodium niobate-based lead-free high energy storage density and energy storage efficiency ceramic green body.

[0099] (8) The obtained ceramic green body is subjected to a degassing treatment at 600°C for 12 h, and then the degassed ceramic green body is heated to 1270°C at a heating rate of 3°C / min under a closed condition and kept for 2 h, and finally cooled to room temperature in the furnace to obtain a sodium niobate-based lead-free high energy storage density and energy storage efficiency ceramic.

[0100] The obtained sodium niobate-based lead-free ceramic is plated with gold electrodes by ion sputtering method, and the electric hysteresis loop of the material is tested at room temperature and 10 Hz by using a ferroelectric test system (Precision Premier II, USA), and the energy storage characteristics can be calculated by the following formula:

[0101] (1)

[0102] (2)

[0103] (3)

[0104] In the formula, W tot represents the total energy storage density, W rec represents the releasable energy density, and W loss represents the energy loss density. P is the polarization strength, P max is the maximum polarization strength, and P r is the remanent polarization strength.Figure 3 The figure shows the hysteresis loop of the sodium niobate-based lead-free ceramic dielectric material prepared in Example 3, measured at room temperature and 10 Hz. As can be seen from the figure, the hysteresis loop of the sodium niobate-based lead-free ceramic dielectric material prepared in this invention is slender, with a high breakdown electric field strength, reaching a maximum electric field strength of 830 kV / cm. The energy storage characteristics (total energy storage density W) are calculated based on the hysteresis loops under different electric field strengths. tot The available energy storage density W rec Energy loss density W loss The curves showing the variation of energy storage efficiency η with electric field intensity are as follows: Figure 8 As shown in the figure. From the figure, we can see that W tot and W rec W increases rapidly with increasing electric field strength. loss It increases slowly with increasing electric field strength. Within the electric field strength range of 100–830 kV / cm, η stabilizes around 85%. When the electric field strength reaches 830 kV / cm, W… tot =11.32J / cm 3 W rec = 9.38 J / cm 3 W loss = 1.94 J / cm 3 The corresponding η is 82.87%.

[0105] Example 4

[0106] This embodiment provides a sodium niobate-based lead-free ceramic dielectric material and its preparation method, wherein the chemical composition of the ceramic is (1-x)(0.85NaNbO3-0.15Sr). 0.7 Bi 0.2 TiO3)-xCaHfO3+0.1wt%MnCO3, where x = 0.06. The specific preparation steps are as follows:

[0107] (1) Select Bi2O3, SrCO3, CaCO3, HfO2, TiO2, Na2CO3, Nb2O5 and MnCO3 with a purity greater than 98% as raw materials for sodium niobate-based lead-free ceramic dielectric materials;

[0108] (2) According to the chemical formula (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2TiO3)-xCaHfO3 (wherein x = 0.06) are weighed and mixed uniformly by a primary ball milling process to obtain the initial raw material powder; wherein ZrO2 balls and anhydrous ethanol are used as the ball milling medium, the mass ratio of ZrO2 balls to the raw material is 3:1, the mass ratio of anhydrous ethanol to the raw material is 1.2:1, the rotation speed of the ball mill is 400 r / min, and the ball milling time is 12 h.

[0109] (3) The dried raw material powder is calcined at 850℃ for 4 h under a sealed condition to obtain a pre-synthesized ceramic powder;

[0110] (4) 0.1 wt% MnCO3 is added to the pre-synthesized ceramic powder and secondary ball milling is performed, and the slurry after ball milling is dried at 100℃; wherein ZrO2 balls and anhydrous ethanol are used as the ball milling medium, the mass ratio of ZrO2 balls to the raw material is 3.0:1, the mass ratio of anhydrous ethanol to the raw material is 1.5:1, the rotation speed of the ball mill is 400 r / min, and the ball milling time is 12 h;

[0111] (5) The raw material powder after drying in step (4) is sieved through a 200 mesh sieve to obtain the raw material powder of the sodium niobate-based lead-free high energy storage density and energy storage efficiency ceramic dielectric material;

[0112] (6) The obtained raw material powder is mixed with an organic solvent, an emulsifier, a plasticizer, a binder and a dispersant to obtain a slurry of the sodium niobate-based lead-free ceramic dielectric material. The organic solvent is a mixture of anhydrous ethanol and butanone; the emulsifier is glyceryl trioleate; the plasticizer is dibutyl phthalate; the binder is polyvinyl butyral; and the dispersant is polyethylene glycol. The amount of anhydrous ethanol added is 50% of the mass of the raw material powder; the amount of butanone added is 90% of the mass of the raw material powder; the amount of glyceryl trioleate added is 3% of the mass of the raw material powder; the amount of polyvinyl butyral added is 9.5% of the mass of the raw material powder; the amount of polyethylene glycol added is 3% of the mass of the raw material powder; and the amount of dibutyl phthalate added is 3% of the mass of the raw material powder;

[0113] (7) The obtained ceramic slurry is prepared into a ceramic film by a tape casting process, and then cut into a square piece of 10 mm x 10 mm, and then pressed at a pressure of 50 MPa, 100 MPa, 150 MPa and 200 MPa in turn at 75℃ to obtain a sodium niobate-based lead-free ceramic green body;

[0114] (8) The obtained ceramic green body is subjected to a degassing treatment at 600℃ for 12 h, and then the degassed ceramic green body is heated to 1270℃ at a heating rate of 3℃ / min under a sealed condition and held for 2 h, and finally cooled to room temperature in the furnace to obtain a sodium niobate-based lead-free high energy storage density and energy storage efficiency ceramic.

[0115] The obtained sodium niobate-based lead-free ceramic dielectric material was plated with gold electrodes by ion sputtering method. The electric hysteresis loop of the material was tested at room temperature and 10 Hz using a ferroelectric test system (Precision Premier II, USA), and the energy storage properties can be calculated by the following formula:

[0116] (1)

[0117] (2)

[0118] (3)

[0119] In the formula, W tot represents the total energy storage density, W rec represents the available energy density, and W loss represents the energy loss density. P is the polarization intensity, P max is the maximum polarization intensity, and P r is the remanent polarization intensity. Figure 4 The electric hysteresis loop of the sodium niobate-based lead-free high-energy storage density and energy storage efficiency ceramic prepared in Example 4 was measured at room temperature and 10 Hz. As can be seen from the figure, the electric hysteresis loop of the sodium niobate-based lead-free ceramic dielectric material prepared in the present application is slender, and the breakdown electric field strength is high, and the maximum electric field strength can reach 800 kV / cm. The energy storage properties (total energy storage density W tot , available energy density W rec , energy loss density W loss and energy storage efficiency η) calculated based on the electric hysteresis loop at different electric field strengths change with the electric field strength curve as shown in Figure 9 From the figure, it can be found that W tot and W rec increase rapidly with the increase of the electric field strength, and W loss increases slowly with the increase of the electric field strength. In the electric field strength range of 100-910 kV / cm, η is stable at about 90%. When the electric field strength reaches 910 kV / cm, W tot = 10.93 J / cm 3 , W rec = 9.70 J / cm 3 , W loss = 1.23 J / cm 3 , and the corresponding η is 88.76%.

[0120] Example 5

[0121] The embodiment provides a sodium niobate-based lead-free ceramic dielectric material and a preparation method thereof, wherein the chemical composition of the ceramic is (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)-xCaHfO3+0.1 wt%MnCO3, wherein x = 0.08. The specific preparation steps are as follows:

[0122] (1) Bi2O3, SrCO3, CaCO3, HfO2, TiO2, Na2CO3, Nb2O5 and MnCO3 with a purity greater than 98% are selected as raw materials of the sodium niobate-based lead-free ceramic dielectric material;

[0123] (2) the raw materials are weighed according to the chemical formula (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 TiO3)-xCaHfO3 (wherein x = 0.08), and the raw materials are uniformly mixed through a one-time ball milling process to obtain initial raw material powder; wherein, when ball milling, anhydrous ethanol and ZrO2 balls are used as the ball milling medium, the mass ratio of the ZrO2 balls to the raw materials is 3:1, the mass ratio of the anhydrous ethanol to the raw materials is 1.2:1, the rotating speed of the ball mill is 400 r / min, and the ball milling time is 12h.

[0124] (3) the dried raw material powder is calcined at 850 DEG C for 4h under a closed condition to obtain pre-synthesized ceramic powder;

[0125] (4) 0.1 wt% MnCO3 is added to the pre-synthesized ceramic powder, and secondary ball milling is performed, and the slurry after ball milling is dried at 100 DEG C; wherein, when ball milling, anhydrous ethanol and ZrO2 balls are used as the ball milling medium, the mass ratio of the ZrO2 balls to the raw materials is 3.0:1, the mass ratio of the anhydrous ethanol to the raw materials is 1.5:1, the rotating speed of the ball mill is 400 r / min, and the ball milling time is 12h;

[0126] (5) the raw material powder of the sodium niobate-based lead-free ceramic dielectric material is obtained by screening the raw material powder after drying in step (4) through a 200-mesh screen;

[0127] (6) The obtained raw material powder is mixed with organic solvent, emulsifier, plasticizer, binder and dispersant respectively to obtain the slurry of sodium niobate-based lead-free ceramic dielectric material. The organic solvent is a mixture of anhydrous ethanol and butanone; the emulsifier is glyceryl trioleate; the plasticizer is dibutyl phthalate; the binder is polyvinyl butyral; and the dispersant is polyethylene glycol. The anhydrous ethanol is added in an amount of 50% of the mass of the raw material powder; the butanone is added in an amount of 90% of the mass of the raw material powder; the glyceryl trioleate is added in an amount of 3% of the mass of the raw material powder; the polyvinyl butyral is added in an amount of 9.5% of the mass of the raw material powder; the polyethylene glycol is added in an amount of 3% of the mass of the raw material powder; and the dibutyl phthalate is added in an amount of 3% of the mass of the raw material powder;

[0128] (7) The obtained ceramic slurry is prepared into a ceramic film through a flow casting process, and then cut into a square piece with a size of 10 mm x 10 mm, and then pressed at a pressure of 50 MPa, 100 MPa, 150 MPa and 200 MPa in sequence at 75°C to obtain a green body of the sodium niobate-based lead-free ceramic dielectric material.

[0129] (8) The obtained ceramic dielectric material green body is subjected to degassing treatment at 600°C for 12 h, and then the degassed ceramic green body is heated to 1270°C at a heating rate of 3°C / min under a closed condition and kept for 2 h, and finally cooled to room temperature in the furnace to obtain the sodium niobate-based lead-free ceramic dielectric material.

[0130] The obtained sodium niobate-based lead-free ceramic dielectric material is plated with gold electrodes by ion sputtering method, and the electric hysteresis loop of the material is tested at room temperature and 10 Hz by using a ferroelectric test system (Precision Premier II, USA), and the energy storage characteristics can be calculated by the following formula:

[0131] (1)

[0132] (2)

[0133] (3)

[0134] In the formula, W tot represents the total energy storage density, W rec represents the releasable energy density, and W loss represents the energy loss density. P is the polarization strength, P max is the maximum polarization strength, and P r is the remanent polarization strength. Figure 5The figure shows the hysteresis loop of the sodium niobate-based lead-free ceramic dielectric material prepared in Example 5, measured at room temperature and 10 Hz. As can be seen from the figure, the hysteresis loop of the sodium niobate-based lead-free ceramic dielectric material prepared in this invention is slender, with a high breakdown electric field strength, reaching a maximum electric field strength of 800 kV / cm. The energy storage characteristics (total energy storage density W) are calculated based on the hysteresis loops under different electric field strengths. tot The available energy storage density W rec Energy loss density W loss The curves showing the variation of energy storage efficiency η with electric field intensity are as follows: Figure 10 As shown in the figure. It can be seen from the figure that W tot and W rec W increases rapidly with increasing electric field strength. loss It increases slowly with increasing electric field strength. Within the electric field strength range of 100–920 kV / cm, η stabilizes around 90%. When the electric field strength reaches 920 kV / cm, W… tot =10.55J / cm 3 W rec = 9.41 J / cm 3 W loss = 1.14 J / cm 3 The corresponding η is 89.22%.

[0135] Example 6

[0136] Compared with Example 4, it is mostly the same, except that step (2) is changed to:

[0137] According to the chemical formula (1-x)(0.85NaNbO3-0.15Sr) 0.7 Bi 0.2 The raw materials (TiO3)-xCaHfO3 (where x = 0.06) were weighed and mixed uniformly through a single ball milling process to obtain the initial raw material powder. Anhydrous ethanol and ZrO2 balls were used as the ball milling media. The mass ratio of ZrO2 balls to raw materials was 2.5:1, and the mass ratio of anhydrous ethanol to raw materials was 1.5:1. The ball mill speed was 450 r / min, and the ball milling time was 15 h.

[0138] Example 7

[0139] Compared with Example 3, it is mostly the same, except that step (3) is changed to:

[0140] The dried raw material powder was calcined at 800℃ for 6 hours under sealed conditions to obtain pre-synthesized ceramic powder.

[0141] Example 8

[0142] Mostly the same as Example 3, except that step (4) is changed to:

[0143] 0.1 wt% MnCO3 was added into the pre-synthesized ceramic powder and secondary ball milling was carried out. The slurry after ball milling was dried at 100°C; wherein the ball milling was carried out using absolute ethyl alcohol and ZrO2 balls as the ball milling medium, the mass ratio of ZrO2 balls to raw materials was 2.5:1, the mass ratio of absolute ethyl alcohol to raw materials was 1.2:1, the rotation speed of the ball mill was 450 r / min, and the ball milling time was 15 h.

[0144] Example 9

[0145] Mostly the same as Example 3, except that step (6) is changed to:

[0146] The obtained raw material powder was mixed with organic solvent, emulsifier, plasticizer, binder and dispersant to obtain the slurry of the sodium niobate-based lead-free ceramic dielectric material. The organic solvent was a mixture of absolute ethyl alcohol and butanone; the emulsifier was glycerol trioleate; the plasticizer was dibutyl phthalate; the binder was polyvinyl butyral; and the dispersant was polyethylene glycol. The addition amount of absolute ethyl alcohol was 45% of the mass of the raw material powder; the addition amount of butanone was 110% of the mass of the raw material powder; the addition amount of glycerol trioleate was 2.5% of the mass of the raw material powder; the addition amount of polyvinyl butyral was 8% of the mass of the raw material powder; the addition amount of polyethylene glycol was 2.5% of the mass of the raw material powder; and the addition amount of dibutyl phthalate was 2.5% of the mass of the raw material powder.

[0147] Example 10

[0148] Mostly the same as Example 3, except that step (6) is changed to:

[0149] The obtained raw material powder was mixed with organic solvent, emulsifier, plasticizer, binder and dispersant to obtain the slurry of the sodium niobate-based lead-free ceramic dielectric material. The organic solvent was a mixture of absolute ethyl alcohol and butanone; the emulsifier was glycerol trioleate; the plasticizer was dibutyl phthalate; the binder was polyvinyl butyral; and the dispersant was polyethylene glycol. The addition amount of absolute ethyl alcohol was 60% of the mass of the raw material powder; the addition amount of butanone was 110% of the mass of the raw material powder; the addition amount of glycerol trioleate was 3.5% of the mass of the raw material powder; the addition amount of polyvinyl butyral was 14% of the mass of the raw material powder; the addition amount of polyethylene glycol was 3.5% of the mass of the raw material powder; and the addition amount of dibutyl phthalate was 3.5% of the mass of the raw material powder.

[0150] Example 11

[0151] Mostly the same as Example 3, except that step (8) is changed to:

[0152] The obtained ceramic green body was degreased at 550℃ for 6h, then the degreased ceramic green body was heated to 1200℃ at a heating rate of 3℃ / min under airtight condition and kept for 2h, and finally cooled to room temperature with the furnace to obtain a sodium niobate-based lead-free high energy storage density and energy storage efficiency ceramic.

[0153] Comparative Example 1

[0154] Most of them are the same as Example 3, except that MnCO3 is not added. In the range of 100~650kV / cm electric field intensity, η is stable around 80%. When the electric field intensity reaches 650kV / cm, W tot = 7.59 J / cm 3 , W rec = 6.07 J / cm 3 , W loss = 1.52 J / cm 3 , and the corresponding η is 79.95%.

[0155] Comparative Example 2

[0156] Most of them are the same as Example 3, except that the preparation process is changed to a solid phase reaction method. In the range of 100~500kV / cm electric field intensity, η is stable around 88%. When the electric field intensity reaches 500kV / cm, W tot = 4.33 J / cm 3 , W rec = 3.76 J / cm 3 , W loss = 0.57 J / cm 3 , and the corresponding η is 86.88%.

[0157] Comparative Example 3

[0158] Most of them are the same as Example 3, except that MnCO3 in it is replaced by MnSO4. Because MnSO4 produces more oxygen vacancies when it is heated and decomposed and volatilized, the performance of the ceramic deteriorates. In the range of 100~400kV / cm electric field intensity, η is stable around 70%. When the electric field intensity reaches 400kV / cm, W tot = 3.56 J / cm 3 , W rec = 2.41 J / cm 3 , W loss = 1.15 J / cm 3 , and the corresponding η is 67.66%.

[0159] From the analysis of Example 3, Comparative Example 1 and Comparative Example 2, without adding manganese carbonate or using solid phase reaction method for preparation, the total energy storage density W tot , the available energy storage density W rec is obviously reduced, the energy loss density W loss is obviously increased, and the energy storage efficiency η is obviously reduced, which shows that the addition of manganese carbonate in the formula of the present application can significantly reduce the leakage, reduce the remanent polarization, increase the breakdown field strength while maintaining the high saturation polarization of sodium niobate, so that the energy storage density of sodium niobate-based lead-free ceramic dielectric is greatly improved.

[0160] The above description of the examples is for the purpose of facilitating the understanding and use of the present application by those skilled in the art. Those skilled in the art can obviously make various modifications to the examples and apply the general principles described herein to other examples without having to go through creative labor. Therefore, the present application is not limited to the above examples, and any improvements and modifications made by those skilled in the art within the scope of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. A sodium niobate-based lead-free ceramic dielectric material, characterized in that, This ceramic dielectric material was prepared by a casting process, and its chemical composition is (1-x)(0.85NaNbO3-0.15Sr). 0.7 Bi 0.2 The formula is: TiO3)-xCaHfO3+0.01-0.2wt%MnCO3, where x = 0.02~0.08, and 0.01-0.2wt%MnCO3 indicates that the MnCO3 content is 0.01-0.2wt% of the total mass of the ceramic dielectric material; the maximum breakdown field strength of the ceramic dielectric material is 800~920 kV / cm; and the total energy storage density of the ceramic dielectric material at the maximum breakdown field strength is 8.88~11.32 J / cm³. 3 .

2. A method for preparing a sodium niobate-based lead-free ceramic dielectric material as described in claim 1, characterized in that, Includes the following steps: S1: Bi2O3, SrCO3, CaCO3, HfO2, TiO2, Na2CO3, Nb2O5 and MnCO3 are selected as raw materials; S2: According to (1-x)(0.85NaNbO3-0.15Sr 0.7 Bi 0.2 The TiO3-xCaHfO3 were prepared in stoichiometric ratio and mixed uniformly by ball milling in one step, wherein x = 0.02-0.08; S3: Calcine the raw materials of the ingredients in S2 to obtain pre-synthesized ceramic powder; S4: Add MnCO3 to the pre-synthesized ceramic powder obtained in S3 and ball mill it a second time. Then dry it and pass it through a 200-mesh sieve to obtain the raw material powder of sodium niobate-based lead-free ceramic media material. S5: Add organic solvent, emulsifier, plasticizer, binder and dispersant to the raw material powder of sodium niobate-based lead-free ceramic dielectric material obtained in S4 and mix evenly to obtain a slurry of sodium niobate-based lead-free ceramic dielectric material; S6: The slurry of sodium niobate-based lead-free ceramic dielectric material obtained in S5 is used to prepare a ceramic film of the corresponding composition through a casting process. Then, it is cut and subjected to isostatic pressing to obtain a green body of sodium niobate-based lead-free ceramic dielectric material. S7: The sodium niobate-based ceramic dielectric material green body obtained in S6 is subjected to debinding treatment and heat preservation, and then sintered to obtain sodium niobate-based ceramic dielectric material.

3. The method for preparing a sodium niobate-based lead-free ceramic dielectric material according to claim 2, characterized in that, In S2 and S4, the specific conditions for one ball milling are as follows: anhydrous ethanol and ZrO2 balls are used as the ball milling media, the mass ratio of ZrO2 balls, anhydrous ethanol and raw materials is (2.5-3.0):(1.2-1.5):1, the ball milling speed is 400-450 r / min, and the ball milling time is 12-15h. The specific conditions for secondary ball milling are as follows: anhydrous ethanol and ZrO2 balls are used as the ball milling media, the mass ratio of ZrO2 balls, anhydrous ethanol and raw materials is (2.5-3.0):(1.2-1.5):1, the ball milling speed is 400-450 r / min, and the ball milling time is 12-15h.

4. The method for preparing a sodium niobate-based lead-free ceramic dielectric material according to claim 2, characterized in that, In S3, the specific calcination conditions are: calcination at 700-950℃ for 3-8 hours under sealed conditions.

5. The method for preparing a sodium niobate-based lead-free ceramic dielectric material according to claim 2, characterized in that, In S4, the amount of MnCO3 added is 0.01-0.2% of the sum of the raw material mass and the amount of MnCO3 after the ingredients in S2.

6. The method for preparing a sodium niobate-based lead-free ceramic dielectric material according to claim 2, characterized in that, In step S5, the organic solvent is a mixture of anhydrous ethanol and butanone, wherein the amount of anhydrous ethanol added is 45-60% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material; and the amount of butanone added is 90-110% of the mass of the raw material powder of the sodium niobate-based lead-free ceramic dielectric material. The emulsifier is trioleic acid glyceride, and the amount of trioleic acid glyceride added is 2.5-3.5% of the mass of the raw material powder of sodium niobate-based lead-free ceramic dielectric material; The plasticizer is dibutyl phthalate, and the amount of dibutyl phthalate added is 2.5-3.5% of the mass of the raw material powder of sodium niobate-based lead-free ceramic dielectric material; The binder is polyvinyl butyral, and the amount of polyvinyl butyral added is 8-14% of the mass of the raw material powder of sodium niobate-based lead-free ceramic dielectric material; The dispersant is polyethylene glycol, and the amount of polyethylene glycol added is 2.5-3.5% of the mass of the raw material powder of sodium niobate-based lead-free ceramic media material.

7. The method for preparing a sodium niobate-based lead-free ceramic dielectric material according to claim 2, characterized in that, In S6, the specific conditions for isostatic pressing are: temperature 50-100℃, and pressure of 50 MPa, 100 MPa, 150 MPa and 200 MPa respectively.

8. The method for preparing a sodium niobate-based lead-free ceramic dielectric material according to claim 2, characterized in that, In S7, the glue removal process is carried out at 500-700℃, and the heat preservation time is 6-14h.

9. The method for preparing a sodium niobate-based lead-free ceramic dielectric material according to claim 2, characterized in that, In S7, the sintering conditions are as follows: under sealed conditions, the temperature is increased from room temperature to 1000-1350℃ at a heating rate of 3-4℃ / min and held for 1-4 hours, and then naturally cooled to room temperature with the furnace.

10. An application of the sodium niobate-based lead-free ceramic dielectric material as described in claim 1, characterized in that, This ceramic dielectric material is used as an energy storage material in the fields of laser, radar, mobile communication, or aerospace.

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