Preparation method and application of BaZrO3 material with adjustable piezoelectric property
By mixing BaZrO3 powder with a reducing agent and then subjecting it to heat treatment, the distribution of oxygen vacancies can be controlled, thus solving the problem of regulating the piezoelectric properties of BaZrO3. This enables precise control of lead-free piezoelectric materials and expands their applications in medical devices, energy harvesting, and piezoelectric catalysis.
Patent Information
- Application Number
- CN202511801473.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-02-10
AI Technical Summary
Existing technologies make it difficult to easily and efficiently control the piezoelectric properties of barium zirconate (BaZrO3), and traditional methods may lead to excessive accumulation of oxygen vacancies, which can damage the crystal structure and limit its application in lead-free piezoelectric materials.
By mixing BaZrO3 powder with a reducing agent and then subjecting it to heat treatment, the generation and distribution of oxygen vacancies can be controlled, the crystal symmetry can be broken, and a built-in electric field can be introduced, thereby achieving precise control of piezoelectric properties.
The piezoelectric properties of BaZrO3 material can be controlled and adjusted, making it suitable for lead-free piezoelectric elements, replacing traditional lead-containing materials, and applicable to medical devices, energy harvesting devices, and piezoelectric catalysis.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of inorganic functional material preparation technology, specifically relating to a barium zirconate (BaZrO3) material with tunable piezoelectric properties and its preparation method, as well as the application of this material in energy harvesting, medical devices and piezoelectric catalysis. Background Technology
[0002] Piezoelectric materials are functional materials capable of converting mechanical energy into electrical energy, and they have wide applications in sensors, actuators, energy harvesting devices, and catalysis. Traditional piezoelectric materials, such as lead zirconate titanate (PZT) series, while possessing excellent piezoelectric properties, contain biotoxic lead, making them absolutely prohibited in implantable or close-contact medical devices and contradicting current green and environmentally friendly development trends. Therefore, the development of high-performance lead-free piezoelectric materials has become a research hotspot in this field.
[0003] Barium zirconate (BaZrO3), a typical perovskite-type lead-free material, has attracted attention due to its excellent chemical and thermal stability. However, its crystal structure exhibits a highly symmetrical cubic phase at room temperature. This centrosymmetric crystal structure means that it does not possess piezoelectric effects on a macroscopic scale, which greatly limits its application in the piezoelectric field.
[0004] Currently, researchers are attempting to control the crystal structure and properties of BaZrO3 by elemental doping (such as Ti, Sn, etc.) or by preparing non-stoichiometric BaZrO3. However, these methods have some limitations, such as a limited range of dopant element types and concentrations, complex processes, and the potential introduction of unwanted defects that adversely affect the intrinsic properties of the material. Therefore, developing a simple, efficient, and precisely controllable method for preparing BaZrO3 piezoelectric materials is crucial for expanding its application in lead-free piezoelectric systems.
[0005] Although the creation of oxygen defects or vacancies has been reported to break crystal symmetry and induce local piezoelectric polarization, its practical application in BaZrO3 remains challenging and lacks significant advancements. First, the controllable introduction of oxygen vacancies is difficult; common methods such as hydrogen reduction involve harsh reaction conditions that can lead to excessive accumulation of oxygen vacancies, forming extended defects and even disrupting the perovskite framework structure, thus hindering piezoelectric control. Second, a simple and reproducible method is lacking for precisely controlling the piezoelectric properties of BaZrO3, making it difficult to systematically study its influencing factors and identify the optimal performance point. Therefore, developing a simple, efficient, and reproducible technique to activate the piezoelectric activity of BaZrO3 and effectively control its piezoelectric properties is of significant practical importance. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a simple process for preparing BaZrO3 materials with precisely controllable piezoelectric properties, as well as its applications.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A method for preparing BaZrO3 material with tunable piezoelectric properties includes the following steps:
[0009] (1) Preparation of precursor colloid: Soluble zirconium salt and barium salt are dissolved in solvent at a molar ratio of 1:1 to form a precursor mixed solution. Then, the mixed solution is added dropwise to an alkaline solution and stirred continuously to form a uniform colloid.
[0010] (2) Hydrothermal synthesis: The colloid obtained in step (1) is transferred to a hydrothermal reactor and subjected to a hydrothermal reaction at a certain temperature. After the reaction is completed, it is naturally cooled to room temperature. The obtained product is filtered, washed and dried to obtain pure phase BaZrO3 powder.
[0011] (3) Reduction treatment: The BaZrO3 powder obtained in step (2) is ground and mixed with the reducing agent at a certain mass ratio to ensure full contact between the two; then the uniformly mixed powder is heat-treated under an inert atmosphere for 0.5 to 10 hours; after the reaction is completed, the product is cooled to room temperature, washed and dried to obtain the piezoelectrically adjustable BaZrO3 material.
[0012] Preferably, in step (1), the zirconium salt is at least one of ZrCl4, ZrOCl2·8H2O, Zr(SO4)2·4H2O, and Zr(NO3)4; the barium salt is at least one of BaCl2, Ba(CH3COO)2, Ba(ClO3)2, Ba(OH)2·8H2O, Ba(NO3)2, and BaCO3; the alkaline solution is sodium hydroxide, potassium hydroxide, or an ammonia solution, and the concentration of the alkaline solution is 1-6 mol / L; the mixing process is carried out at room temperature, and the mixture is stirred for 10-60 minutes after mixing to form the colloid.
[0013] Preferably, in step (2), the temperature of the hydrothermal reaction is 120-240℃ and the reaction time is 6-48 hours; the washing liquid used for washing is one or more of deionized water, ethanol or dilute acid solution; the drying temperature is 60-100℃ and the drying time is 8-24 hours.
[0014] Preferably, in step (3), the reducing agent is at least one of NaBH4, NaBH3CN, NaBH(OCOCH3)3 or KBH4; the mass ratio of BaZrO3 powder to reducing agent is 1:0.01 to 1:5; the inert atmosphere is argon or nitrogen; the heat treatment temperature is 400-900℃ and the time is 0.5-10 hours.
[0015] Compared with the prior art, the core innovation of this invention lies in:
[0016] The high symmetry of the original BaZrO3 crystal structure was cleverly broken through subsequent reducing agent heat treatment steps. The reducing agent reacts with ions on or near the surface of BaZrO3, potentially generating defects such as oxygen vacancies, leading to lattice distortion and inducing a built-in electric field, thus endowing the originally piezoelectric BaZrO3 with piezoelectric properties. By precisely controlling the mass ratio of BaZrO3 to reducing agent, as well as the heat treatment temperature and time, the concentration and distribution of defects can be controlled, thereby achieving precise and continuous control over the piezoelectric properties of BaZrO3 materials.
[0017] This invention also protects the application of BaZrO3 materials with tunable piezoelectric properties prepared by the above method. The materials can be used for:
[0018] Implantable or close-contact medical devices: As biocompatible lead-free piezoelectric elements, they are used to fabricate implantable sensors, drug-controlled release micropumps, or tissue engineering scaffolds, etc.
[0019] Mechanical energy harvesting devices: convert vibrations, noise, or pressure signals from the environment into electrical energy to power micro- and nano-electronic devices (such as IoT sensor nodes).
[0020] In the field of piezoelectric catalysis, piezoelectric effects are used to drive catalytic reactions under the action of sound waves or mechanical vibrations, such as in the synthesis of ammonia (N2 fixation), water splitting to produce hydrogen, and degradation of organic pollutants, as highly efficient catalysts.
[0021] The beneficial effects of this invention:
[0022] Compared with existing technologies, the present invention provides a method for preparing BaZrO3 materials with tunable piezoelectric properties and its applications, which have the following significant advantages:
[0023] 1. The BaZrO3 material with adjustable piezoelectric properties described in this invention can replace traditional lead-containing piezoelectric materials due to its lead-free piezoelectric characteristics, and can prevent the biotoxicity of lead in implantable or close-contact medical devices.
[0024] 2. The piezoelectrically tunable BaZrO3 material of the present invention introduces piezoelectric properties by creating oxygen defects in the symmetrical BaZrO3 crystal structure to break the symmetry structure.
[0025] 3. This invention can precisely control the piezoelectric properties of BaZrO3 by simply adjusting the molar ratio of the reducing agent to the BaZrO3 precursor. This method is simple, has good repeatability, and is easy to scale up. Attached Figure Description
[0026] Figure 1 Scanning electron microscope images of barium zirconate prepared in Example 1 (left) and Example 4 (right).
[0027] Figure 2 The PE hysteresis loop characterizes the precise control of the piezoelectric properties of barium zirconate. Detailed Implementation
[0028] The present invention will be further illustrated below through specific embodiments. These embodiments are merely illustrative and explanatory of the invention and should not be construed as limiting the scope of protection of the invention. All technologies implemented based on the above description of the present invention are covered within the scope of protection intended by the present invention.
[0029] Example 1:
[0030] ZrCl4 and BaCl2 were dissolved in distilled water at a molar ratio of 1:1 to form a precursor mixed solution. This mixed solution was then added dropwise to a 1 mol / L sodium hydroxide solution, and stirred continuously at room temperature for 10 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 120°C for 6 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with deionized water, and dried at 60°C for 8 hours to obtain BaZrO3 powder. The BaZrO3 powder and NaBH4 were ground and mixed at a molar ratio of 1:0.01 to ensure full contact. The homogeneous powder was then heat-treated under a nitrogen atmosphere at 400°C for 0.5 hours. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the piezoelectrically adjustable BaZrO3 material.
[0031] Example 2:
[0032] ZrOCl2·8H2O and Ba(CH3COO)2 were dissolved in distilled water at a molar ratio of 1:1 to form a precursor mixed solution. This mixed solution was then added dropwise to a 1 mol / L potassium hydroxide solution, and stirred continuously at room temperature for 60 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 240°C for 48 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with ethanol, and dried at 100°C for 24 hours to obtain BaZrO3 powder. The BaZrO3 powder was then ground and mixed with NaBH3CN at a molar ratio of 1:5 to ensure sufficient contact between the two. The homogeneous powder was then heat-treated under an argon atmosphere at a temperature of 900°C for 10 hours. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the piezoelectrically adjustable BaZrO3 material.
[0033] Example 3:
[0034] Zr(SO4)2·4H2O and Ba(ClO3)2 were dissolved in distilled water at a molar ratio of 1:1 to form a precursor mixed solution. This mixed solution was then added dropwise to a 3 mol / L ammonia solution, and stirred continuously at room temperature for 30 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 200°C for 12 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with dilute sulfuric acid, and dried at 80°C for 14 hours to obtain BaZrO3 powder. The BaZrO3 powder was then ground and mixed with NaBH(OCOCH3)3 at a molar ratio of 1:1 to ensure full contact. The homogeneous powder was then heat-treated under a nitrogen atmosphere at 500°C for 2 hours. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the piezoelectrically adjustable BaZrO3 material.
[0035] Example 4:
[0036] Zr(NO3)4 and Ba(OH)2·8H2O were dissolved in distilled water at a molar ratio of 1:1 to form a precursor mixed solution. This mixed solution was then added dropwise to a 4 mol / L potassium hydroxide solution, and stirred continuously at room temperature for 40 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 140°C for 18 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with deionized water, and dried at 80°C for 14 hours to obtain BaZrO3 powder. The BaZrO3 powder was then ground and mixed with KBH4 at a molar ratio of 1:3 to ensure full contact. The homogeneous powder was then heat-treated under a nitrogen atmosphere at 600°C for 5 hours. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the piezoelectrically adjustable BaZrO3 material.
[0037] Example 5:
[0038] ZrCl4 and Ba(NO3)2 were dissolved in distilled water at a molar ratio of 1:1 to form a precursor mixed solution. This mixed solution was then added dropwise to a 5 mol / L sodium hydroxide solution, and stirred continuously at room temperature for 50 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 240°C for 48 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with deionized water, and dried at 80°C for 20 hours to obtain BaZrO3 powder. The BaZrO3 powder was then ground and mixed with NaBH3CN at a molar ratio of 1:0.1 to ensure sufficient contact between the two. The homogeneous powder was then heat-treated under a nitrogen atmosphere at 900°C for 6 hours. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the piezoelectrically adjustable BaZrO3 material.
[0039] Example 6:
[0040] Zr(NO3)4 and BaCO3 were dissolved in distilled water at a molar ratio of 1:1 to form a precursor mixture solution. This mixture solution was then added dropwise to a 4 mol / L potassium hydroxide solution, and stirred continuously at room temperature for 20 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 240°C for 6 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with ethanol, and dried at 60°C for 8 hours to obtain BaZrO3 powder. The BaZrO3 powder was then ground and mixed with NaBH4 at a molar ratio of 1:0.5 to ensure sufficient contact between the two. The homogeneous powder was then heat-treated under an argon atmosphere at a temperature of 400°C for 3 hours. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the piezoelectrically adjustable BaZrO3 material.
[0041] Comparative Example 1:
[0042] ZrCl4 and BaCl2 were dissolved in distilled water at a molar ratio of 1:1 to form a precursor mixed solution. This mixed solution was then added dropwise to a 1 mol / L sodium hydroxide solution, and stirred continuously at room temperature for 10 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 120°C for 6 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with deionized water, and dried at 60°C for 8 hours to obtain BaZrO3 powder. The BaZrO3 powder was then heat-treated under a nitrogen atmosphere at 400°C for 0.5 hours. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the BaZrO3 material.
[0043] In Comparative Example 1, the preparation of the precursor colloid and the hydrothermal synthesis steps were exactly the same as in Example 1, except that the reducing agent heat treatment step (3) was omitted, and the resulting BaZrO3 powder was directly tested for performance. X-ray diffraction characterization showed that its crystal structure was a highly symmetrical cubic phase, and its piezoelectric coefficient (d...) was... 33 The test results were close to zero, and the hydrogen production rate in the piezoelectric catalytic water splitting experiment was extremely low, comparable to the background noise level. Comparative Example 1 directly demonstrates that without the reduction treatment of this invention, the traditional BaZrO3 material has no piezoelectric activity, thus highlighting the indispensability of the steps in this invention.
[0044] Comparative Example 2:
[0045] ZrOCl2·8H2O and Ba(CH3COO)2 were dissolved in distilled water to form a precursor mixed solution. This mixed solution was then added dropwise to a 1 mol / L potassium hydroxide solution, and stirred continuously at room temperature for 60 minutes to form a homogeneous colloid. The resulting colloid was transferred to a hydrothermal reactor and hydrothermally reacted at 240°C for 48 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered, washed with ethanol, and dried at 100°C for 24 hours to obtain BaZrO3 powder. The BaZrO3 powder was then placed in a tube furnace and reduced at 500°C for 2 hours under a pure hydrogen atmosphere. After the reaction, the product was cooled to room temperature, washed, and dried to obtain the BaZrO3 material.
[0046] Comparative Example 2 prepared BaZrO3 powder in the same way as Example 2. In the reduction process, Comparative Example 2 directly placed barium zirconate in a tube furnace and carried out the reduction treatment at 500°C for 2 hours under a pure hydrogen atmosphere.
[0047] XRD patterns indicate that the phase shown in Comparative Example 2 is impure, with some BaZrO3 being over-reduced to metallic barium and zirconium oxide. The piezoelectric coefficient (d...) 33 The performance degradation was lower than that of Example 2 of this invention. In the piezoelectric catalytic stability test, the performance degradation was faster. This demonstrates that the traditional hydrogen reduction method is a violent reaction, difficult to control precisely, and easily damages the main structure. In contrast, the reduction method of this invention is milder, more controllable, and has superior performance.
[0048] Comparative Example 3:
[0049] Lead acetate, zirconium oxychloride, and tetrabutyl titanate were dissolved in methanol in a molar ratio of 1:1:2 to form a homogeneous mixed solution. This mixed solution was then added dropwise to a 1 mol / L potassium hydroxide solution, and the mixture was stirred continuously at room temperature for 60 minutes to form a homogeneous colloid. The resulting gel was subjected to a hydrothermal reaction at 300°C for 12 hours. After the reaction was completed, the gel was allowed to cool naturally to room temperature. The resulting product was filtered, washed with ethanol, and calcined at 600°C for 6 hours to obtain PbZrO3 powder.
[0050] Compared with Comparative Examples 1-6, the lead zirconate material prepared in Comparative Example 3 contains lead, which is biotoxic, and therefore cannot be used in invasive or contact medical applications where safety requirements are extremely high, such as ultrasound probes, implantable pressure sensors, targeted drug release and treatment.
Claims
1. A method for preparing a BaZrO3 material with tunable piezoelectric properties, characterized in that, Its preparation method includes the following steps: (1) Preparation of precursor colloid: Soluble zirconium salt and barium salt are dissolved in solvent at a molar ratio of 1:1 to form a precursor mixed solution. Then, the mixed solution is added dropwise to an alkaline solution and stirred continuously to form a uniform colloid. (2) Hydrothermal synthesis: The colloid obtained in step (1) is transferred to a hydrothermal reactor and hydrothermal reaction is carried out at a certain temperature. After the reaction is completed, it is naturally cooled to room temperature. The obtained product is filtered, washed and dried to obtain BaZrO3 powder. (3) Reduction treatment: The BaZrO3 powder obtained in step (2) is ground and mixed with the reducing agent at a certain molar ratio to ensure full contact between the two; then the uniformly mixed powder is heat-treated under an inert atmosphere; after the reaction is completed, the product is cooled to room temperature, washed and dried to obtain the BaZrO3 material with adjustable piezoelectric properties.
2. The preparation method according to claim 1, characterized in that, The zirconium salt mentioned in step (1) is at least one of ZrCl4, ZrOCl2·8H2O, Zr(SO4)2·4H2O and Zr(NO3)4; the barium salt is at least one of BaCl2, Ba(CH3COO)2, Ba(ClO3)2, Ba(OH)2·8H2O, Ba(NO3)2 and BaCO3; the alkaline solution is sodium hydroxide, potassium hydroxide or ammonia solution, preferably, the concentration of the alkaline solution is 1-6 mol / L.
3. The preparation method according to claim 1, characterized in that, In step (1), the mixing process is carried out at room temperature, and the mixture is stirred for 10-60 minutes after mixing to form the colloid.
4. The preparation method according to claim 1, characterized in that, In step (2), the temperature of the hydrothermal reaction is 120-240℃ and the reaction time is 6-48 hours.
5. The preparation method according to claim 1, characterized in that, In step (2), the washing liquid used for washing is one or more of deionized water, ethanol or dilute acid solution; the drying temperature is 60-100℃ and the drying time is 8-24 hours.
6. The preparation method according to claim 1, characterized in that, In step (3), the reducing agent is at least one of NaBH4, NaBH3CN, NaBH(OCOCH3)3 or KBH4; the mass ratio of BaZrO3 powder to reducing agent is 1:0.01 to 1:
5.
7. The preparation method according to claim 1, characterized in that, In step (3), the inert atmosphere is nitrogen or argon.
8. The preparation method according to claim 1, characterized in that, In step (3), the heat treatment temperature is 400-900℃ and the time is 0.5-10 hours.
9. A BaZrO3 material with tunable piezoelectric properties, characterized in that, It is prepared by the method according to any one of claims 1 to 8.
10. The application of a BaZrO3 material with tunable piezoelectric properties as described in claim 9 in the preparation of piezoelectric devices or piezoelectric catalysts.
11. The application according to claim 10, characterized in that, The piezoelectric device is an implantable medical device, a close-contact medical device, or a mechanical energy harvesting device; the piezoelectric catalysis field is the field of ammonia synthesis, water splitting to produce hydrogen, or degradation of organic pollutants.