CN113185282A - High-temperature stable sodium bismuth titanate-based energy storage capacitor material and preparation method thereof - Google Patents

Abstract

The invention discloses a high-temperature stable sodium bismuth titanate-based energy storage capacitor material and a preparation method thereof, wherein the chemical composition of the capacitor material is (1-x) (0.98(0.94 (Bi)_0.5Na_0.5)TiO₃‑0.06BaTiO₃)‑0.02Sr_0.8Na_0.4Nb₂O₆)‑xNaNbO₃Wherein x is 0.15; the preparation process of the capacitor material comprises the steps of drying the original powder, and then weighing the original powder according to the molar ratio of atoms in the molecular formula of the material; and then presintering the raw material after primary ball milling, then carrying out isostatic pressing after secondary ball milling, and finally sintering in the air atmosphere of a high-temperature furnace. The sodium bismuth titanate-based energy storage capacitor material with high temperature stability is prepared by the invention, and the energy storage density and the energy storage efficiency at room temperature are respectively 1.67J/cm³And 78%. And has good energy storage temperature stability at high temperature. Compared with the energy storage stability of the similar capacitor ceramics in the temperature range of room temperature to 160 ℃, the ceramic has obvious advantages in energy storage performance.

Description

High-temperature stable sodium bismuth titanate-based energy storage capacitor material and preparation method thereof

Technical Field

The invention relates to the technical field of capacitor materials, and is mainly applied to the field of energy storage ceramic capacitors.

Background

Energy storage materials have gained widespread attention in recent decades with ever increasing demands on energy. Ceramic-based dielectric ceramics have received attention from many researchers due to their small size, good temperature stability, good mechanical properties, fast charge and discharge rates, and high energy density. The working temperature in the fields of electronic devices close to engines in aerospace, engine sensors of automobiles and the like is higher. Therefore, in the practical application of the dielectric capacitor ceramic, in addition to the consideration of high energy storage density and efficiency, the temperature stability of the energy storage performance is another critical factor to be considered.

(Bi_0.5Na_0.5)TiO₃The material is a potential energy storage material due to high polarization intensity, but the material has large residual polarization intensity at room temperature, which causes reduction of energy storage density and energy storage efficiency. To increase (Bi)_0.5Na_0.5)TiO₃The energy storage performance of the composite material is modified by a plurality of researchers, and the addition of other perovskite structure materials is considered to be an effective mode for improving the energy storage performance. The improvement of the energy storage performance is mainly due to the enhancement of the relaxivity, and the relaxation is represented by a slender electric hysteresis loop, a large difference value between the maximum polarization intensity and the residual polarization intensity, namely delta P_max-P_r。

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a high-temperature stable sodium bismuth titanate-based energy storage capacitor material. Using tungsten bronze structure material Sr_0.8Na_0.4Nb₂O₆To (Bi)_0.5Na_0.5)TiO₃-0.06BaTiO₃The dielectric constant temperature stability of the modified ceramic is improved, but the breakdown field strength is lower. In order to improve the breakdown field strength and further improve the energy storage density, NaNbO is adopted₃For (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆) Modification was conducted to investigateIt was found that the energy storage density was increased and high temperature stability was maintained.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme: a high-temperature stable sodium bismuth titanate-based energy storage capacitor material comprises (1-x) (0.98(0.94 (Bi)) of chemical composition_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein x is 0.15; the preparation process of the capacitor material comprises the steps of drying original powder, and then weighing a proper amount of the original powder; and then presintering the raw material after primary ball milling, then carrying out isostatic pressing after secondary ball milling, and finally sintering in the air atmosphere of a high-temperature furnace. Recoverable energy storage density W of capacitor material under 70kV/cm electric field_recIs 1.67J/cm³The energy storage efficiency eta is 78%, and the change rates of the ceramic energy storage density and the efficiency are respectively less than 5.25% and 4.82% in the temperature range from room temperature to 160 ℃.

Preferably, the chemical composition formula (1-x) (0.98(0.94 (Bi) is selected according to the capacitance material_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein the molar ratio of x to atoms in 0.15 is used for calculating the needed original powder Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃The mass of Bi contained in the sample before weighing₂O₃And Na₂CO₃Drying for 2-4h at the temperature of 300-350 ℃, and obtaining TiO₂Drying for 2-4h at the temperature of 800-₃、Nb₂O₅And BaCO₃Drying at 80-120 deg.C for 12-25 h.

The preparation method for preparing the high-temperature stable sodium bismuth titanate-based energy storage capacitor material comprises the following steps:

step 1: weighing original powder;

step 2: performing primary ball milling, and presintering at 800-900 ℃ after ball milling;

the step 2 specifically comprises the following steps: the weighed Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃Placing the mixture in a nylon ball milling tank, taking absolute ethyl alcohol as a grinding medium, and adopting a planetary ball mill at the rotation speed of 250-260rpm for 24-28 h; then drying the mixture in an oven at the temperature of 80-100 ℃ for 12-15h, and then pre-pressing and forming; then heating to 800-900 ℃ at the heating rate of 3-5 ℃/min in a high-temperature muffle furnace for pre-sintering, wherein the heat preservation time is 2-4 h; finally, the temperature is reduced to 300 ℃ at the cooling rate of 8-10 ℃/min, and finally the temperature is cooled to the room temperature along with the furnace.

And step 3: then, performing secondary ball milling on the pre-sintered powder, and then forming under the isostatic pressure of 150-200 MPa;

step 3, grinding the powder pre-burned in the step 2 in an agate grinding bowl; then placing the mixture into a nylon ball milling tank for secondary ball milling, wherein the grinding medium is absolute ethyl alcohol, the rotating speed is 250-260rpm, and the ball milling time is 24-28 h; then, the mixture is pressed and molded by adopting a cold isostatic pressing process, the molding pressure is 150-200MPa, and the pressure maintaining time is 5-7 min.

And 4, step 4: sintering in the air atmosphere of a high-temperature furnace, wherein the heating rate is 3-5 ℃/min, the sintering temperature is 1125-plus 1175 ℃, the heat preservation time is 2-4h, then the temperature is reduced to 250-plus 300 ℃ at the cooling rate of 8-10 ℃/min, and finally the temperature is cooled to the room temperature along with the furnace.

(III) advantageous effects

The invention provides a high-temperature stable sodium bismuth titanate-based energy storage capacitor material. The method has the following beneficial effects:

the sodium bismuth titanate-based energy storage capacitor material with high temperature stability is prepared by the invention, and the energy storage density and the energy storage efficiency at room temperature are respectively 1.67J/cm³And 78%. And has good energy storage temperature stability at high temperature. Compared with the energy storage stability of the similar capacitor ceramics in the temperature range from room temperature to 160 ℃, the ceramic energy storage performance has obvious advantages, the change rate of the energy storage density is less than 5.25%, and the change rate of the energy storage efficiency is less than 4.82%. The source of the raw materials for preparation is wide, and the prepared ceramic is compact,The crystal grain size is uniform, the dielectric property is excellent, the preparation process is simple, the cost is low, and the repeatability is good.

Drawings

FIG. 1: XRD patterns of the ceramic dielectric materials prepared in example 1 of the present invention and comparative examples 1, 2, and 3.

FIG. 2: SEM scanning electron micrographs of the surface microstructures of the ceramic dielectric materials prepared in example 1 of the present invention and comparative examples 1, 2, and 3.

FIG. 3: the dielectric constant and loss of the ceramic dielectric materials prepared in example 1 of the present invention and comparative examples 1, 2 and 3 are plotted as a function of temperature.

FIG. 4: the change graphs of the hysteresis loop and the energy storage density of the ceramic dielectric materials prepared in the example 1 and the comparative examples 1, 2 and 3 of the invention under different electric fields.

FIG. 5: the P-I-E curve chart of the ceramic dielectric materials prepared in the embodiment 1 and the comparative examples 1, 2 and 3 of the invention at normal temperature.

FIG. 6: P-E diagram of ceramic dielectric materials prepared in example 1 and comparative examples 1, 2 and 3 of the invention in the temperature range from room temperature to 180 DEG C

FIG. 7: graph of variation trend of energy storage density and energy storage efficiency of ceramic dielectric materials prepared in example 1 and comparative examples 1, 2 and 3 of the invention in a temperature range from room temperature to 180 DEG C

FIG. 8: the ceramic dielectric material ceramics prepared in the embodiment 1 and the comparative examples 1, 2 and 3 of the invention have (a) discharge current change curves along with time under different electric fields in an over-damping state; (b) energy storage density W under different electric fields_dA graph of time; (c) curve of discharge current with temperature and (d) energy storage density at temperature W_dA graph of time;

FIG. 9: the ceramic dielectric materials prepared in the embodiment 1 and the comparative examples 1, 2 and 3 of the invention have (a) discharge current waveform graphs with time under the underdamped state in different electric fields; (b) current density C_DAnd power density P_DA trend graph of values with electric field variation; (c) time-varying waveform of discharge current at different temperatures and (d) current density C_DAnd power density P_DThe values are plotted against the temperature.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

An XRD (model: XRD-7000, CuK alpha, lambda is 0.15406nm, Shimadzu, Japan) tester is adopted to test the phase structure of the prepared ceramic; the surface appearance of the ceramic is characterized by adopting SEM (model: JEOL, JSM-6700F, Japan) (before appearance characterization, samples are polished and then are subjected to hot corrosion treatment for 30 minutes at the temperature of 100 ℃ lower than the sintering temperature); the dielectric constant and dielectric loss of the ceramics at room temperature to 400 ℃ were measured using a dielectric tester (model E4980A, Agilent, American) with a hot stage attached, at test frequencies of 1kHz, 5kHz, 10kHz, 100kHz and 1 MHz. The hysteresis loop was tested by a ferroelectrics (model: 1000aixACCT, Germany) at a frequency of 1Hz and at a temperature ranging from room temperature to 180 ℃.

Example 1

1) Firstly Bi is added₂O₃And Na₂CO₃Drying at 300 deg.C for 2 hr to obtain TiO₂Drying at 800 deg.C for 2h with SrCO₃、Nb₂O₅And BaCO₃Drying at 100 deg.C for 12 h. Then according to (1-x) (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein x is 0.15 molar ratio of metal atoms to calculate the substrate raw material Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃The mass of the steel is accurately weighed;

2) the weighed Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃Placing the mixture into a nylon ball milling tank, taking absolute ethyl alcohol as a grinding medium, wherein the rotating speed of an adopted planetary ball mill is 250rpm, and the ball milling time is 24 hours; then placing the mixture in an oven at 80 ℃ for 12h for drying, and then pre-pressing and forming; then, heating to 800 ℃ in a high-temperature muffle furnace at the heating rate of 5 ℃/min for presintering, wherein the heat preservation time is 2 hours; finally, the temperature is reduced to 300 ℃ at the cooling rate of 10 ℃/min, and finally, the temperature is cooled to room temperature along with the furnace.

3) Grinding the powder subjected to pre-sintering in the step (2) in an agate grinding bowl; then placing the mixture into a nylon ball milling tank for secondary ball milling, wherein the grinding medium is absolute ethyl alcohol, the rotating speed is 250rpm, and the ball milling time is 24 hours; then, pressing and forming by adopting a cold isostatic pressing process, wherein the forming pressure is 200MPa, and the pressure maintaining time is 5 min; and after forming, placing the ceramic material in a high-temperature furnace, raising the temperature to 1150 ℃ at the temperature raising rate of 5 ℃/min, preserving the heat for 2h, then reducing the temperature to 300 ℃ at the temperature lowering rate of 10 ℃/min, and finally cooling the ceramic material to room temperature along with the furnace to obtain the capacitor ceramic material a.

Comparative example 1:

1) firstly Bi is added₂O₃And Na₂CO₃Drying at 300 deg.C for 2 hr to obtain TiO₂Drying at 800 deg.C for 2h with SrCO₃、Nb₂O₅And BaCO₃Drying at 100 deg.C for 12 h. Then according to (1-x) (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein x is 0.20 molar ratio of metal atoms in the matrix raw material Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃The mass of the steel is accurately weighed;

2) the weighed Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃Placing the mixture into a nylon ball milling tank, taking absolute ethyl alcohol as a grinding medium, wherein the rotating speed of an adopted planetary ball mill is 250rpm, and the ball milling time is 24 hours; then placing the mixture in an oven at 80 DEG CDrying for 12h, and then pre-pressing and forming; then, heating to 800 ℃ in a high-temperature muffle furnace at the heating rate of 5 ℃/min for presintering, wherein the heat preservation time is 2 hours; finally, the temperature is reduced to 300 ℃ at the cooling rate of 10 ℃/min, and finally, the temperature is cooled to room temperature along with the furnace.

3) Grinding the powder subjected to pre-sintering in the step (2) in an agate grinding bowl; then placing the mixture into a nylon ball milling tank for secondary ball milling, wherein the grinding medium is absolute ethyl alcohol, the rotating speed is 250rpm, and the ball milling time is 24 hours; then, pressing and forming by adopting a cold isostatic pressing process, wherein the forming pressure is 200MPa, and the pressure maintaining time is 5 min; and (3) after molding, placing the ceramic material in a high-temperature furnace, heating to 1150 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, then reducing the temperature to 300 ℃ at the cooling rate of 10 ℃/min, and finally cooling to room temperature along with the furnace to obtain the capacitor ceramic material b.

Comparative example 2:

1) firstly Bi is added₂O₃And Na₂CO₃Drying at 300 deg.C for 2 hr to obtain TiO₂Drying at 800 deg.C for 2h with SrCO₃、Nb₂O₅And BaCO₃Drying at 100 deg.C for 12 h. Then according to (1-x) (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein x is 0.25 molar ratio of metal atoms to calculate the substrate raw material Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃The mass of the steel is accurately weighed;

2) the weighed Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃Placing the mixture into a nylon ball milling tank, taking absolute ethyl alcohol as a grinding medium, wherein the rotating speed of an adopted planetary ball mill is 250rpm, and the ball milling time is 24 hours; then placing the mixture in an oven at 80 ℃ for 12h for drying, and then pre-pressing and forming; then, heating to 800 ℃ in a high-temperature muffle furnace at the heating rate of 5 ℃/min for presintering, wherein the heat preservation time is 2 hours; finally, the temperature is reduced to 300 ℃ at the cooling rate of 10 ℃/min, and finally, the furnace is cooledAnd then cooled to room temperature.

3) Grinding the powder subjected to pre-sintering in the step (2) in an agate grinding bowl; then placing the mixture into a nylon ball milling tank for secondary ball milling, wherein the grinding medium is absolute ethyl alcohol, the rotating speed is 250rpm, and the ball milling time is 24 hours; then, pressing and forming by adopting a cold isostatic pressing process, wherein the forming pressure is 200MPa, and the pressure maintaining time is 5 min; and (3) after molding, placing the ceramic material in a high-temperature furnace, heating to 1150 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, then reducing the temperature to 300 ℃ at the cooling rate of 10 ℃/min, and finally cooling to room temperature along with the furnace to obtain the capacitor ceramic material c.

Comparative example 3:

1) firstly Bi is added₂O₃And Na₂CO₃Drying at 300 deg.C for 2 hr to obtain TiO₂Drying at 800 deg.C for 2h with SrCO₃、Nb₂O₅And BaCO₃Drying at 100 deg.C for 12 h. Then according to (1-x) (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein the molar ratio of the metal atoms in x ═ 0.30 is used to calculate the matrix material Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃The mass of the steel is accurately weighed;

2) the weighed Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃Placing the mixture into a nylon ball milling tank, taking absolute ethyl alcohol as a grinding medium, wherein the rotating speed of an adopted planetary ball mill is 250rpm, and the ball milling time is 24 hours; then placing the mixture in an oven at 80 ℃ for 12h for drying, and then pre-pressing and forming; then, heating to 800 ℃ in a high-temperature muffle furnace at the heating rate of 5 ℃/min for presintering, wherein the heat preservation time is 2 hours; finally, the temperature is reduced to 300 ℃ at the cooling rate of 10 ℃/min, and finally, the temperature is cooled to room temperature along with the furnace.

3) Grinding the powder subjected to pre-sintering in the step (2) in an agate grinding bowl; then placing the mixture into a nylon ball milling tank for secondary ball milling, wherein the grinding medium is absolute ethyl alcohol, the rotating speed is 250rpm, and the ball milling time is 24 hours; then, pressing and forming by adopting a cold isostatic pressing process, wherein the forming pressure is 200MPa, and the pressure maintaining time is 5 min; and (3) after molding, placing the ceramic material in a high-temperature furnace, heating to 1150 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, then reducing the temperature to 300 ℃ at the cooling rate of 10 ℃/min, and finally cooling to room temperature along with the furnace to obtain the capacitor ceramic material d.

As can be seen from FIG. 1, when x is changed from 0.15 to 0.30, the XRD pattern has no impurity peaks, and the ceramic materials are all pure perovskite structures.

As can be seen from FIG. 2, the prepared ceramic is dense and has a grain size of 2 μm or less.

As can be seen from FIG. 3, when NaNbO is used₃When the content of (b) is small, that is, when x is 0.15, two dielectric peaks appear on a change curve of dielectric constant with temperature. The low-temperature dielectric peak shows the typical characteristics of a relaxor ferroelectric body at the temperature of 56-96 ℃; the dielectric peak of the high temperature section is quite different from that of the low temperature section, and the peak is weak and independent of frequency.

As can be seen from FIG. 4, the energy storage density increases with the increase of the electric field intensity, and with the NaNbO₃The increase in content, at the same field strength, reduces the energy storage density. (1-x) (0.98(0.94 (Bi)_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaN bO₃When x is 0.15, the energy storage density value of the unit electric field under the electric field intensity E of 140kV/cm reaches 119J/(kV · m)²) This value is higher than the corresponding variation value of other BNT-based ceramics under proper electric field

As can be seen from fig. 5, the hysteresis loops at room temperature are all in a slender shape, and represent the characteristics of the hysteresis loop of typical relaxor ferroelectrics in various states. The long and thin electric hysteresis loop and no obvious current peak indicate that the NaNbO is₃Added (1-x) (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃And x is 0.15-0.30 of the ceramic in obvious passing each phase. NaNbO₃Increase in the amount of addition (x is 0.15 to x is 0.30), and energy storage density W_recFrom 1.67J/cm³Reduced to 1.42J/cm³And the energy storage efficiency η rises from 78% to 85%.

As can be seen from FIG. 6, (1-x) (0.98(0.94 (Bi)) of different composition with increasing temperature_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaN bO₃The ceramic with x being 0.15-0.30 shows a slender electric hysteresis loop and the maximum polarization intensity P_maxSlowly decreases with temperature and the remanent polarization P_rIs not sensitive to temperature.

As can be seen from FIG. 7, the change rate of the energy storage density of all the component ceramics is Δ W/W within the temperature range from room temperature to 180 deg.C_RTAre all less than 15 percent. The change rate of the energy storage efficiency is within 10 percent. Wherein the composition is (1-x) (0.98(0.94 (Bi)_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃The ceramic with x being 0.15 has better temperature stability, and the change rate of the energy storage density and the efficiency in the temperature range from room temperature to 160 ℃ is 5.25 percent and 4.82 percent respectively.

As shown in FIG. 8, (1-x) (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃X-0.15 ceramic has a fast discharge rate in an over-damped state, t_0.9Has a value of about 0.1 mus and has a good temperature stability of the storage density and the discharge rate in the temperature range of room temperature to 100 ℃.

As shown in FIG. 9, (1-x) (0.98(0.94 (Bi))_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃The ceramic with x being 0.15 has fast discharge speed in an underdamped state, discharge time of 0.26 mus and good temperature stability of current density and power density in a temperature range from room temperature to 100 ℃.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation. The use of the phrase "comprising one of the elements does not exclude the presence of other like elements in the process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (3)

1. The high-temperature stable sodium bismuth titanate-based energy storage capacitor material is characterized in that the chemical composition of the capacitor material is (1-x) (0.98(0.94 (Bi)_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein x is 0.15; the preparation process of the capacitor material comprises the steps of drying original powder, and then weighing a proper amount of the original powder; and then presintering the raw material after primary ball milling, then carrying out isostatic pressing after secondary ball milling, and finally sintering in the air atmosphere of a high-temperature furnace.

2. The high-temperature stable sodium bismuth titanate-based energy storage capacitor material as claimed in claim 1, wherein: according to the chemical composition formula (1-x) (0.98(0.94 (Bi)) of the capacitor material_0.5Na_0.5)TiO₃-0.06BaTiO₃)-0.02Sr_0.8Na_0.4Nb₂O₆)-xNaNbO₃Wherein the molar ratio of x to atoms in 0.15 is used for calculating the needed original powder Bi₂O₃、TiO₂、Na₂CO₃、Nb₂O₅、BaCO₃And SrCO₃The mass of Bi contained in the sample before weighing₂O₃And Na₂CO₃Drying for 2-4h at the temperature of 300-350 ℃, and obtaining TiO₂Drying for 2-4h at the temperature of 800-₃、Nb₂O₅And BaCO₃Drying at 80-120 deg.C for 12-15 h.

3. A method for preparing a high temperature stable sodium bismuth titanate based energy storage capacitor material according to claims 1-2, comprising the steps of:

step 1: weighing original powder;

step 2: performing primary ball milling, and presintering for 2-4h at the temperature of 800-900 ℃ after ball milling;

and step 3: then, performing secondary ball milling on the pre-sintered powder, and then forming under the isostatic pressure of 150-200 MPa;

and 4, step 4: sintering in the air atmosphere of a high-temperature furnace, wherein the heating rate is 3-5 ℃/min, the sintering temperature is 1125-plus 1175 ℃, the heat preservation time is 2-4h, then the temperature is reduced to 250-plus 300 ℃ at the cooling rate of 8-10 ℃/min, and finally the temperature is cooled to the room temperature along with the furnace.

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