Method for improving electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric material

Abstract

A method for improving the electrocaloric effect of a ferroelectric perovskite material, comprising: weighing Ba, Sr, Ca, Hf, Sn, Zr, and Ti sources and mixing same uniformly according to a stoichiometric ratio; performing pre-sintering to obtain (BaxSryCazA1-x-y-z)(Hf aSn bZrcTidB1-a-b-c-d)O3 powder; after fine grinding and mixing with a binder, granulating the mixture, followed by forming, aging, and de-plasticizing to obtain a ceramic green body; and finally performing sintering to obtain a barium titanate-based ferroelectric perovskite electrocaloric material having high electrocaloric performance. In the present invention, barium titanate ceramic is used as a matrix, and elemental precursors such as zirconium, hafnium, tin, strontium, and calcium are introduced during solid-phase synthesis, and multi-element doping is performed at both the A-site and B-site to substitute into the BaTiO3 material. After blending and high-temperature sintering, the finished product is obtained. The method features simple preparation conditions, mature processes, low costs, and high reliability. Under the induction of an electrical field, a large entropy change and strong electrocaloric effect are generated.

Description

Methods to improve the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials Technical Field

[0001] This invention relates to a technology in the field of all-solid-state refrigeration materials, specifically a method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials. Background Technology

[0002] The electrocaloric effect is an important development direction for the development of new refrigeration equipment, and doping is an effective means to improve the performance of electrocaloric materials. However, existing doping techniques, due to their small doping amounts or limited doping types, do not significantly alter the overall material structure. The electrocaloric effect is essentially the thermal effect resulting from the transition between order and disorder in the polarized structure under the influence of an electric field. Therefore, this multi-element co-doping method can significantly improve the electrocaloric effect. Summary of the Invention

[0003] This invention addresses the shortcomings of existing inorganic ferroelectric materials, which cannot achieve ultra-high electrocaloric strength under high electric fields, and the difficulty in balancing large electrocaloric effects and wide operating temperature ranges in existing inorganic electrocaloric materials. It proposes a method to improve the electrocaloric effect of ferroelectric perovskite materials. Using barium titanate ceramic as a matrix, precursors of zirconium, hafnium, tin, strontium, and calcium are introduced during solid-state synthesis. Multi-element doping is simultaneously applied to the A and B sites to replace BaTiO3 material. The resulting product is obtained by high-temperature sintering after blending. This method features simple preparation conditions, mature technology, low cost, and high reliability. Under electric field induction, it generates a large entropy change and electrocaloric effect.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials. The method involves weighing Ba, Sr, Ca, Hf, Sn, Zr, and Ti sources, mixing them uniformly according to stoichiometric ratios, and then pre-sintering to obtain (Ba... x Sr y Ca z A 1-x-y-z (Hf) a Sn b Zr c Ti d B 1-a-b-c-d O3 powder is finely ground, mixed with a binder, granulated, and then shaped, aged, and descaled to obtain a ceramic green body. Finally, it is sintered to obtain a barium titanate-based ferroelectric perovskite electric material with high electrical properties, wherein: 0.6 ≤ x < 1, 0 < y ≤ 0.4, 0 < z ≤ 0.4, 0 < a ≤ 0.3, 0 < b ≤ 0.3, 0 < c ≤ 0.3, and 0.7 ≤ d < 1.

[0006] The stoichiometric ratio mentioned above refers to the percentage of each element (Ba). x Sr y Ca z A 1-x-y-z (Hf) a Sn b Zr c Ti d B 1-a-b-c-d The chemical composition ratio of O3 materials.

[0007] The Ba source, Sr source, Ca source, Hf source, Sn source, Zr source, and Ti source are oxides containing the element or salts and hydroxides that can decompose into the desired oxide at high temperatures, such as BaO, SrO, CaO, or Ba(OH)2, Sr(OH)2, Ca(OH)2, etc.; preferably BaCO3, SrCO3, CaCO3, HfO2, SnO2, ZrO2, and TiO2.

[0008] The aforementioned pre-sintering refers to: sintering at 2–5°C for [time missing] minutes in an oxygen, air, or nitrogen atmosphere. -1 The heating rate is increased to 1100-1400℃, and the temperature is maintained for 1-6 hours, preferably 2-4 hours, followed by furnace cooling.

[0009] The binder is polyvinyl alcohol, polyethylene glycol, polystyrene, methylcellulose or a combination thereof, and its amount is 5 to 10 wt% of the ceramic powder.

[0010] The aging process refers to aging at room temperature for 22 to 48 hours, preferably 22 to 26 hours.

[0011] The aforementioned plastic removal refers to: in an oxygen or air atmosphere, at a temperature not exceeding 2°C for [time period missing] minutes. -1 The heating rate is increased to 600-800℃, and the temperature is held for 1-3 hours. The preferred temperature for discharging the plastic is 650-750℃.

[0012] The sintering mentioned refers to sintering at 2-5°C in an oxygen, air, or nitrogen atmosphere. -1 The heating rate is increased to 1300-1500℃, preferably 1300-1400℃, and held for 1-6 hours. After sintering, the furnace is cooled to room temperature.

[0013] This invention relates to the barium titanate-based ferroelectric perovskite electrocaloric material prepared by the above method, specifically (Ba 0.8 Sr 0.199 Ca 0.001 (Hf) 0.025 Sn 0.025 Zr 0.025 Ti 0.925 O3、(Ba0.8 Sr 0.2 (Hf) 0.02 Sn 0.02 Zr 0.02 Ti 0.94 O3、(Ba 0.8 Sr 0.199 Ca 0.001 (Hf) 0.03 Sn 0.03 Zr 0.03 Ti 0.91 )O3 or (Ba 0.905 Sr 0.09 Ca 0.005 (Hf) 0.0307 Sn 0.0307 Zr 0.0307 Ti 0.9079 )O3.

[0014] This invention relates to an application of the above-mentioned barium titanate-based ferroelectric perovskite electrocardiogram material, which is used to prepare the electrode layer of a solid-state refrigeration element.

[0015] The application is specifically as follows: magnetron sputtering gold plating is performed on the surface of barium titanate-based ferroelectric perovskite electrocard material, and a gold electrode layer is obtained after deposition in a vacuum at a current of 0.2~0.3 nA for 30~180 s.

[0016] This invention refines the ferroelectric domains in inorganic ferroelectric ceramics, increasing the substrate entropy that can induce the electrocaloric effect and optimizing the electrocaloric strength. Compared with existing technologies, this invention significantly improves the electrocaloric strength while refining the ferroelectric domains in inorganic ferroelectric ceramics, significantly increasing the domain wall density, improving the polarization freedom of the material, increasing the substrate entropy that can induce the electrocaloric effect, and optimizing the electrocaloric strength, especially under high electric fields. The temperature stability of the electrocaloric effect is improved. Multi-element co-doping ensures the simultaneous existence of various electric dipole moments dispersed in the material, which widens the operating temperature range of this material, enabling it to exhibit a large electrocaloric effect over a relatively wide temperature range near room temperature. Using the electrocaloric refrigeration material of this invention simplifies the design of electrocaloric refrigeration equipment and improves the cooling capacity of electrocaloric refrigerators. Attached Figure Description

[0017] Figure 1 is a scanning electron microscope image of the high-energy-performance ceramic sheet of Example 1;

[0018] Figure 2 is a schematic diagram of the dielectric temperature spectrum of the high electrocaloric performance ceramic material in Example 1;

[0019] Figure 3 is a schematic diagram of the hysteresis loop of the high-electric-calorific-performance ceramic material in Example 1;

[0020] Figure 4 shows the temperature change curve of the electrocaloric effect of the high electrocaloric performance ceramic material of Example 1 as a function of temperature.

[0021] Figure 5 is a schematic diagram of the temperature change curve of the electrocaloric effect of the high electrocaloric performance ceramic materials of Examples 1-4 as a function of electric field strength. Detailed Implementation Example

[0022] Ferroelectric ceramic materials (Ba 0.8 Sr 0.199 Ca 0.001 (Hf) 0.025 Sn 0.025 Zr 0.025 Ti 0.925 Preparation of O3:

[0023] 1) Using BaCO3, SrCO3, CaCO3, HfO2, SnO2, ZrO2, and TiO2 as raw materials, the mixture was prepared according to the stoichiometric ratios shown in the chemical formulas. Wet ball milling was used, with a mass ratio of raw materials:milling ball:ethanol = 1:(2~10):(0.7~1.2), and the mixture was mixed for 16 hours. Zirconia balls were selected as the milling balls. After drying, the mixture was pressed into blocks to obtain mixed powder blocks, which were then heated at 2℃ for 1 minute in air. -1 The temperature was increased to 1200℃ for pre-sintering, held at that temperature for 3 hours, and then cooled in the furnace. The resulting material was then pulverized and passed through a 40-mesh sieve to obtain (Ba). 0.8 Sr 0.199 Ca 0.001 (Hf) 0.025 Sn 0.025 Zr 0.025 Ti 0.925 O3 powder; then a second ball milling is performed using a stirred ball milling method to make the particle size smaller. The stirred ball milling is carried out according to the mass ratio of raw material: ball milling mill: ethanol = 1:10:2. After ball milling for 3 hours, the powder is dried and sieved.

[0024] 2) Take the (Ba) obtained in step 1) 0.8 Sr 0.199 Ca 0.001 (Hf) 0.025 Sn 0.025 Zr 0.025 Ti 0.925 O3 powder was finely ground for 3 hours using a ball milling method, with a mass ratio of raw material: ball mill: ethanol = 1:(2~10):(0.7~1.2). After drying and sieving, 9wt% polyvinyl alcohol (PVA) binder was added and granulated. Subsequently, it was pressed into shape, aged for 24 hours, and then ground again in a mortar and passed through a 40-mesh sieve. The resulting powder was pressed into round discs with a diameter of 12.7 mm and a thickness of 2 mm. Then, it was heated to 700℃ in an air atmosphere and exfoliated for 2 hours to obtain ceramic blanks.

[0025] 3) Place the ceramic green body into an alumina crucible, cover it with calcined powder of the same composition, cover the crucible, and incubate in air at 2°C for 1 minute. -1 The heating rate was increased to 1380℃, held for 2 hours, and then cooled in the furnace to obtain a barium titanate-based ferroelectric ceramic material with high electrocaloric performance.

[0026] This embodiment further utilizes the above-mentioned barium titanate-based ferroelectric ceramic material. The sintered ceramic material sample from step 3 is ground into a ceramic sheet with a thickness of 0.15 mm. After ultrasonic cleaning and drying, the upper and lower surfaces are magnetron sputtered with gold. The gold electrode layer is obtained by depositing the gold electrode layer in a vacuum for 90 s with a current of 0.25 nA.

[0027] Electrocaloric effect thermal flux tests were performed on the ceramic element, and the dielectric temperature spectrum of the ferroelectric ceramic in this embodiment was obtained as shown in Figure 2. The figure shows that this material has a high dielectric constant at room temperature and multiple dielectric peaks near room temperature, indicating its potential for electroinduced phase transition.

[0028] Figure 3 shows a schematic diagram of the hysteresis loop of the ferroelectric ceramic element prepared in this embodiment at room temperature.

[0029] Figure 4 shows the electrocaloric effect temperature curves of the ferroelectric ceramic material prepared in this embodiment under different temperatures and electric field strengths. As can be seen from the figure, this ceramic material has a wide operating temperature range.

[0030] Figure 5 shows the electrocaloric temperature change of the ceramic element prepared in this embodiment as a function of electric field strength, and a comparison with other embodiments (i.e., designs with different compositions). The figure shows that the multi-element coexisting ceramic material designed by this method exhibits high electrocaloric effect strength. Example

[0031] Ferroelectric ceramic materials (Ba 0.8 Sr 0.2 (Hf) 0.02 Sn 0.02 Zr 0.02 Ti 0.94 Preparation of O3:

[0032] 1) Using BaCO3, SrCO3, HfO2, SnO2, ZrO2, and TiO2 as raw materials, the mixture was prepared according to the stoichiometric ratios shown in the chemical formulas. Wet ball milling was used, with a mass ratio of raw materials:milling ball:ethanol = 1:(2~10):(0.7~1.2), and the mixture was mixed for 16 hours. Zirconia balls were selected as the milling balls. After drying, the mixture was pressed into blocks to obtain mixed powder blocks, and then milled at 2℃ for 1 minute in air atmosphere. -1 The temperature was increased to 1200℃ for pre-sintering, held at that temperature for 3 hours, and then cooled in the furnace. The resulting material was then pulverized and passed through a 40-mesh sieve to obtain (Ba).0.8 Sr 0.2 (Hf) 0.02 Sn 0.02 Zr 0.02 Ti 0.94 O3 powder; then a second ball milling is performed using a stirred ball milling method to make the particle size smaller. The stirred ball milling is carried out according to the mass ratio of raw material: ball milling mill: ethanol = 1:10:2. After ball milling for 3 hours, the powder is dried and sieved.

[0033] 2) Take the (Ba) obtained in step 1) 0.8 Sr 0.2 (Hf) 0.02 Sn 0.02 Zr 0.02 Ti 0.94 O3 powder was finely ground for 3 hours using a ball milling method, with a mass ratio of raw material: ball mill: ethanol = 1:(2~10):(0.7~1.2). After drying and sieving, 9wt% polyvinyl alcohol (PVA) binder was added and granulated. Subsequently, it was pressed into shape, aged for 24 hours, and then ground again in a mortar and passed through a 40-mesh sieve. The resulting powder was pressed into round discs with a diameter of 12.7 mm and a thickness of 2 mm. Then, it was heated to 700℃ in an air atmosphere and exfoliated for 2 hours to obtain ceramic blanks.

[0034] 3) Place the ceramic green body into an alumina crucible, cover it with calcined powder of the same composition, cover the crucible, and incubate in air at 2°C for 1 minute. -1 The heating rate was increased to 1380℃, held for 2 hours, and then cooled in the furnace to obtain a barium titanate-based ferroelectric ceramic material with high electrocaloric performance.

[0035] This embodiment further utilizes the above-mentioned barium titanate-based ferroelectric ceramic material. The sintered ceramic material sample from step 3 is ground into a ceramic sheet with a thickness of 0.15 mm. After ultrasonic cleaning and drying, the upper and lower surfaces are magnetron sputtered with gold. The gold electrode layer is obtained by depositing the gold electrode layer in a vacuum for 90 s with a current of 0.25 nA.

[0036] The test results of the temperature change due to the electrocardiogram effect in this embodiment, and the comparison with the results of other embodiments, can be seen in Figure 5. Example

[0037] Ferroelectric ceramic materials (Ba 0.8 Sr 0.199 Ca 0.001 (Hf) 0.03 Sn 0.03 Zr 0.03 Ti 0.91 Preparation of O3:

[0038] 1) Using BaCO3, SrCO3, CaCO3, HfO2, SnO2, ZrO2, and TiO2 as raw materials, the mixture was prepared according to the stoichiometric ratios shown in the chemical formulas. Wet ball milling was used, with a mass ratio of raw materials:milling ball:ethanol = 1:(2~10):(0.7~1.2), and the mixture was mixed for 16 hours. Zirconia balls were selected as the milling balls. After drying, the mixture was pressed into blocks to obtain mixed powder blocks, which were then heated at 2℃ for 1 minute in air. -1 The temperature was increased to 1200℃ for pre-sintering, held at that temperature for 3 hours, and then cooled in the furnace. The resulting material was then pulverized and passed through a 40-mesh sieve to obtain (Ba). 0.8 Sr 0.199 Ca 0.001 (Hf) 0.03 Sn 0.03 Zr 0.03 Ti 0.91 O3 powder; then a second ball milling is performed using a stirred ball milling method to make the particle size smaller. The stirred ball milling is carried out according to the mass ratio of raw material: ball milling mill: ethanol = 1:10:2. After ball milling for 3 hours, the powder is dried and sieved.

[0039] 2) Take the (Ba) obtained in step 1) 0.8 Sr 0.199 Ca 0.001 (Hf) 0.03 Sn 0.03 Zr 0.03 Ti 0.91 O3 powder was finely ground for 3 hours using a ball milling method, with a mass ratio of raw material: ball mill: ethanol = 1:(2~10):(0.7~1.2). After drying and sieving, 9wt% polyvinyl alcohol (PVA) binder was added and granulated. Subsequently, it was pressed into shape, aged for 24 hours, and then ground again in a mortar and passed through a 40-mesh sieve. The resulting powder was pressed into round discs with a diameter of 12.7 mm and a thickness of 2 mm. Then, it was heated to 700℃ in an air atmosphere and exfoliated for 2 hours to obtain ceramic blanks.

[0040] 3) Place the ceramic green body into an alumina crucible, cover it with calcined powder of the same composition, cover the crucible, and incubate in air at 2°C for 1 minute. -1 The heating rate was increased to 1380℃, held for 2 hours, and then cooled in the furnace to obtain a barium titanate-based ferroelectric ceramic material with high electrocaloric performance.

[0041] This embodiment further utilizes the above-mentioned barium titanate-based ferroelectric ceramic material. The sintered ceramic material sample from step 3 is ground into a ceramic sheet with a thickness of 0.15 mm. After ultrasonic cleaning and drying, the upper and lower surfaces are magnetron sputtered with gold. The gold electrode layer is obtained by depositing the gold electrode layer in a vacuum for 90 s with a current of 0.25 nA.

[0042] The test results of the temperature change due to the electrocardiogram effect in this embodiment, and the comparison with the results of other embodiments, can be seen in Figure 5. Example

[0043] Ferroelectric ceramic materials (Ba 0.905 Sr 0.09 Ca 0.005 (Hf) 0.0307 Sn 0.0307 Zr 0.0307 Ti 0.9079 Preparation of O3:

[0044] 1) Using BaCO3, SrCO3, CaCO3, HfO2, SnO2, ZrO2, and TiO2 as raw materials, the mixture was prepared according to the stoichiometric ratios shown in the chemical formulas. Wet ball milling was used, with a mass ratio of raw materials:milling ball:ethanol = 1:(2~10):(0.7~1.2), and the mixture was mixed for 16 hours. Zirconia balls were selected as the milling balls. After drying, the mixture was pressed into blocks to obtain mixed powder blocks, which were then heated at 2℃ for 1 minute in air. -1 The temperature was increased to 1200℃ for pre-sintering, held at that temperature for 3 hours, and then cooled in the furnace. The resulting material was then pulverized and passed through a 40-mesh sieve to obtain (Ba). 0.905 Sr 0.09 Ca 0.005 (Hf) 0.0307 Sn 0.0307 Zr 0.0307 Ti 0.9079 O3 powder; then a second ball milling is performed using a stirred ball milling method to make the particle size smaller. The stirred ball milling is carried out according to the mass ratio of raw material: ball milling mill: ethanol = 1:10:2. After ball milling for 3 hours, the powder is dried and sieved.

[0045] 2) Take the (Ba) obtained in step 1) 0.905 Sr 0.09 Ca 0.005 (Hf) 0.0307 Sn 0.0307 Zr 0.0307 Ti 0.9079 O3 powder was finely ground for 3 hours using a ball milling method, with a mass ratio of raw material: ball mill: ethanol = 1:(2~10):(0.7~1.2). After drying and sieving, 9wt% polyvinyl alcohol (PVA) binder was added and granulated. Subsequently, it was pressed into shape, aged for 24 hours, and then ground again in a mortar and passed through a 40-mesh sieve. The resulting powder was pressed into round discs with a diameter of 12.7 mm and a thickness of 2 mm. Then, it was heated to 700℃ in an air atmosphere and exfoliated for 2 hours to obtain ceramic blanks.

[0046] 3) Place the ceramic green body into an alumina crucible, cover it with calcined powder of the same composition, cover the crucible, and incubate in air at 2°C for 1 minute. -1The heating rate was increased to 1380℃, held for 2 hours, and then cooled in the furnace to obtain a barium titanate-based ferroelectric ceramic material with high electrocaloric performance.

[0047] This embodiment further utilizes the above-mentioned barium titanate-based ferroelectric ceramic material. The sintered ceramic material sample from step 3 is ground into a ceramic sheet with a thickness of 0.15 mm. After ultrasonic cleaning and drying, the upper and lower surfaces are magnetron sputtered with gold. The gold electrode layer is obtained by depositing the gold electrode layer in a vacuum for 90 s with a current of 0.25 nA.

[0048] The test results of the temperature change due to the electrocardiogram effect in this embodiment, and the comparison with the results of other embodiments, can be seen in Figure 5.

[0049] Figure 5 shows the changes in electrocaloric refrigeration temperature of electrocaloric ceramics with different compositions. The preferred composition shown in Example 1 has superior electrocaloric refrigeration performance compared to Examples 2-4. This data demonstrates the important role of composition in regulating the electrocaloric refrigeration performance of ferroelectric ceramic materials, and that the preferred composition can significantly improve performance.

[0050] Compared with existing ceramic composition designs, this invention employs a multi-element co-doping material structure control method, simultaneously introducing multiple elements into the material to increase the polarization entropy of the electrocaloric ceramic, thereby improving its electrocaloric refrigeration performance. The barium titanate-based lead-free ferroelectric ceramic material provided by this invention exhibits excellent electrocaloric performance and good temperature stability. The electrocaloric strength of the optimized composition is greater than 0.5 Km MV. -1 The operating temperature range is greater than 30 K, and the optimal composition (x=0.8, y=0.199, z=0.001, a=0.025, b=0.025, c=0.025, d=0.925) has an electrical calorific value as high as 1 K m MV. -1 The operating temperature range is greater than 60 K near room temperature. At 10 MV m -1 It exhibits high electrocaloric effect and excellent temperature stability below the electric field strength.

Claims

1. A method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials, characterized in that, Ba source, Sr source, Ca source, Hf source, Sn source, Zr source, and Ti source were weighed and mixed uniformly according to stoichiometric ratio, and then pre-sintered to obtain (Ba x Sr y Ca z A 1-x-y-z (Hf) a Sn b Zr c Ti d B 1-a-b-c-d O3 powder; after fine grinding and mixing with a binder, it is granulated, then formed, aged, and descaled to obtain a ceramic green body; finally, through sintering, a barium titanate-based ferroelectric perovskite electrocaloric material with high electrocaloric performance is obtained, wherein: 0.6 ≤ x < 1, 0 <y ≤0.4、0 <z ≤0.4、0 <a ≤0.3、0 <b ≤0.3、0 <c ≤0.3、0.7 ≤d <1。 2. The method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials according to claim 1, characterized in that, The Ba source, Sr source, Ca source, Hf source, Sn source, Zr source, and Ti source are BaO, SrO, CaO, or Ba(OH)2, Sr(OH)2, and Ca(OH)2.

3. The method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials according to claim 1, characterized in that, The aforementioned pre-sintering refers to: in an oxygen, air, or nitrogen atmosphere, at a temperature of 2–5°C for [time missing] minutes. -1 The heating rate is increased to 1100-1400℃, held for 1-6 hours, and then cooled with the furnace.

4. The method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials according to claim 1, characterized in that, The binder is polyvinyl alcohol, polyethylene glycol, polystyrene, methylcellulose or a combination thereof, and its amount is 5 to 10 wt% of the ceramic powder.

5. The method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials according to claim 1, characterized in that, The aging process refers to aging at room temperature for 22 to 48 hours.

6. The method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials according to claim 1, characterized in that, The aforementioned plastic removal refers to: in an oxygen or air atmosphere, at a temperature not exceeding 2°C for [time period missing]. -1 The heating rate is increased to 600-800℃, and the temperature is maintained for 1-3 hours.

7. The method for improving the electrocaloric effect of barium titanate-based ferroelectric perovskite electrocaloric materials according to claim 1, characterized in that, The sintering mentioned refers to the process of sintering at 2-5°C in an oxygen, air, or nitrogen atmosphere. -1 The heating rate is increased to 1300-1500℃, held for 1-6 hours, and then cooled to room temperature with the furnace after sintering.

8. A barium titanate-based ferroelectric perovskite electrocardiogram material prepared by any one of claims 1-7, characterized in that, (Ba 0.8 Sr 0.199 Ca 0.001 )(Hf 0.025 Sn 0.025 Zr 0.025 Ti 0.925 )O3, (Ba 0.8 Sr 0.2 )(Hf 0.02 Sn 0.02 Zr 0.02 Ti 0.94 )O3, (Ba 0.8 Sr 0.199 Ca 0.001 )(Hf 0.03 Sn 0.03 Zr 0.03 Ti 0.91 )O3 or (Ba 0.905 Sr 0.09 Ca 0.005 )(Hf 0.0307 Sn 0.0307 Zr 0.0307 Ti 0.9079 )O3.

9. An application of a barium titanate-based ferroelectric perovskite electrocardiogram material prepared by any one of the methods described in claims 1-7 or as described in claim 8, characterized in that, It is used to prepare the electrode layer of solid-state refrigeration components.

10. The application according to claim 9, characterized in that, in The surface of the barium titanate-based ferroelectric perovskite electrocard material is magnetron sputtered with gold, and the gold electrode layer is obtained by deposition in vacuum at a current of 0.2~0.3nA for 30~180s.

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