Strontium titanate-based capacitor dielectric material with temperature bimodal characteristics, preparation method and application thereof
By introducing the temperature bimodal characteristic into the capacitor dielectric material, the capacitor's self-sensing temperature function is realized, solving the problems of space occupation and response lag of external sensors in high power density circuits, and improving the capacitor's real-time monitoring capability and system safety.
Patent Information
- Application Number
- CN202610343395.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-20
- Publication Date
- 2026-07-10
Smart Images
Figure CN122355703A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electronic functional materials technology, and relates to capacitor dielectric materials and their preparation methods, specifically to a strontium titanate-based capacitor dielectric material with temperature bimodal characteristics, its preparation method, and its application. Background Technology
[0002] With the rapid development of power electronics technology, new energy vehicles, and aerospace, electronic circuit systems are evolving towards higher power density, miniaturization, and integration. As an indispensable energy storage and filtering component in circuits, the stability of capacitors' operating state directly affects the safety and lifespan of the entire system. However, temperature is a key factor affecting capacitor performance degradation and even thermal runaway. Therefore, real-time and accurate temperature monitoring of capacitors and their surrounding environment is particularly important.
[0003] Currently, the mainstream temperature monitoring solution involves mounting a separate thermistor (such as NTC / PTC), thermocouple, or infrared temperature sensor externally or nearby to the capacitor. This solution has significant drawbacks. In highly integrated circuit boards (PCBs) or power modules, adding an extra sensor occupies valuable layout space, hindering miniaturization. Furthermore, the physical distance and thermal resistance between the external sensor and the capacitor's internal dielectric cause the measured temperature to lag behind the actual internal temperature of the capacitor. Under rapid charging / discharging or overload conditions, it is difficult to meet the requirements of high-temperature or low-temperature applications.
[0004] Such temperature differences may cause the protection mechanism to fail, leading to safety hazards. If, without changing the basic structure and manufacturing process of the capacitor, the unique electrical response of the material itself at a specific frequency can be utilized to give it self-sensing capabilities, the aforementioned pain points of external sensors can be solved. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a strontium titanate-based capacitor dielectric material with bimodal temperature characteristics, its preparation method, and its application. By utilizing the material's characteristic that the dielectric loss exhibits a bimodal pattern with temperature at a frequency of 100 kHz, capacitors using this material as the dielectric material possess a temperature self-sensing function, enabling in-situ, accurate, and real-time monitoring of the capacitor's internal temperature, thereby improving the temperature sensing capability and system safety of high-temperature power generation devices.
[0006] This invention is achieved through the following technical solution: A strontium titanate-based capacitor dielectric material exhibits a bimodal temperature characteristic. At a frequency of 100 kHz, its dielectric loss shows a bimodal characteristic as temperature changes, with the peak values corresponding to temperatures of 70±3℃ and 302±3℃, respectively.
[0007] This invention also protects a method for preparing a strontium titanate-based capacitor dielectric material with bimodal temperature characteristics as described above, comprising the following steps: S1. Strontium carbonate and titanium dioxide are mixed in an equimolar ratio, and then ball-milled, dried, pre-calcined, ground and sieved to obtain strontium titanate powder; S2. Tin dioxide and bismuth trioxide are mixed in a molar ratio of 3:1, and then ball-milled, dried, pre-calcined, ground and sieved to obtain bismuth stannate powder. S3. Strontium titanate and bismuth stannate are mixed in a molar ratio of 0.97:0.03, and then ball-milled, dried, ground and sieved, and cold isostatically pressed into shape. S4. Sinter the formed blank at 1380~1400 ℃ and hold for 2~3 h to obtain the material.
[0008] Preferably, the ball milling in step S1 is performed using deionized water or anhydrous ethanol as the medium, at a speed of 300 r / min, for 16 to 32 h. The pre-firing is carried out in an air sintering atmosphere at a temperature of 1100~1250 ℃ for 2~5 h.
[0009] Preferably, the ball milling in step S2 is performed using deionized water or anhydrous ethanol as the medium, at a rotation speed of 300 r / min, for 10-20 h. The pre-firing is carried out in an air sintering atmosphere at a temperature of 900~1100 ℃ for 2~5 h.
[0010] Preferably, the ball milling in step S3 is performed using deionized water or anhydrous ethanol as the medium, at a rotation speed of 300 r / min, for 8 to 12 hours. Preferably, the drying process described in steps S1, S2 and S3 is carried out at a temperature of 80~120℃ for 4~12 hours.
[0011] Preferably, the grinding and sieving described in steps S1, S2 and S3 involves grinding the powder in a mortar and then sieving it through a sieve at a mesh size of 160 to 200.
[0012] The present invention also protects the application of the above-mentioned strontium titanate-based capacitor dielectric material with temperature bimodal characteristics in capacitors for high-temperature power generation devices.
[0013] Compared with the prior art, the present invention has the following beneficial effects: The capacitors prepared using the strontium titanate-based dielectric material of this invention exhibit a bimodal intrinsic temperature characteristic of dielectric loss at 100 kHz. This eliminates the need for additional temperature sensing elements, enabling the capacitor to perform energy storage, filtering, and temperature sensing functions simultaneously. This allows for in-situ, real-time, and accurate internal temperature detection, completely eliminating the temperature measurement deviation and response lag issues of traditional external sensors. It saves layout space and meets the demands of high power density, miniaturization, and integration in electronic circuit systems. The dual temperature peaks correspond to specific temperature thresholds, enabling tiered temperature warnings across the entire operating range from normal operation to extreme high temperatures. This provides precise signals for system temperature protection mechanisms, avoiding the limitations of single monitoring. Real-time and accurate internal temperature monitoring allows the control system to promptly detect temperature anomalies and trigger protection, mitigating capacitor performance degradation and thermal runaway risks from the source, significantly improving the stability and safety of electronic system operation. The strontium titanate-based capacitor dielectric material prepared by this invention achieves a 100 kHz performance frequency that matches the operating frequency of the power electronic system of a high-temperature power generation device, without the need for adjustment devices. The temperature measurement function can be applied in industrial applications, avoiding the risk of capacitor thermal runaway and performance failure from the source, and ensuring the stable and safe operation of the high-temperature power generation device. The material of this invention does not use expensive doping elements such as rare earth elements, and the preparation process is simple, controllable, green and environmentally friendly. While achieving technological upgrading, it effectively controls production costs and lays a solid foundation for large-scale industrial application. Attached Figure Description
[0014] Figure 1 The graph shows the dielectric constant and dielectric loss of the strontium titanate-based material sintered in Example 3 as a function of frequency at 25°C. Figure 2 The graph shows the dielectric constant and dielectric loss of the strontium titanate-based material sintered in Example 3 as a function of temperature at 100 kHz. Detailed Implementation
[0015] The present invention will be further described in detail below with reference to specific embodiments.
[0016] Example 1 This embodiment provides a strontium titanate-based capacitor dielectric material with bimodal temperature characteristics, and its preparation method includes the following steps: S1. Strontium carbonate powder and titanium dioxide powder were mixed in an equimolar ratio and ball-milled for 16 h with anhydrous ethanol as the medium at a speed of 300 r / min. After ball milling, the powder was dried in an oven at 120 ℃ for 4 h. The dried powder was then placed in a muffle furnace at 1250 ℃ and kept at that temperature for 2.5 h. The sintered powder was then ground in a mortar and sieved through a 160 mesh to prepare strontium titanate powder. S2. Tin dioxide powder and bismuth trioxide powder were mixed at a molar ratio of 3:1 and ball-milled for 10 h with anhydrous ethanol as the medium at a speed of 300 r / min. After ball milling, the powder was dried in an oven at 120 ℃ for 4 h. The dried powder was then placed in a muffle furnace at 900 ℃ and kept at that temperature for 5 h. The sintered powder was then ground in a mortar and sieved through a 160 mesh to prepare bismuth stannate powder. S3. Strontium titanate powder and bismuth stannate powder were mixed at a molar ratio of 0.97:0.03 and then ball-milled for 8 h with anhydrous ethanol as the medium at a speed of 300 r / min. After ball milling, the powder was placed in an oven at 120℃ and dried for 4 h. The dried powder was then ground in a mortar and sieved through a 160-mesh sieve, and then cold isostatic pressing was performed to form the powder.
[0017] S4. After cold isostatic pressing, high-temperature sintering is carried out at a temperature of 1390 ℃ and a holding time of 2.5 h.
[0018] Example 2 This embodiment provides a strontium titanate-based capacitor dielectric material with bimodal temperature characteristics, and its preparation method includes the following steps: S1. Strontium carbonate powder and titanium dioxide powder were mixed in an equimolar ratio and ball-milled for 32 h with deionized water as the medium at a speed of 300 r / min. After ball milling, the powder was dried in an oven at 80 ℃ for 8 h. The dried powder was then placed in a muffle furnace at 1100 ℃ and held for 5 h. The sintered powder was then ground in a mortar and sieved through a 200-mesh sieve to prepare strontium titanate powder. S2. Tin dioxide powder and bismuth trioxide powder were mixed at a molar ratio of 3:1 and ball-milled for 12 h with deionized water as the medium at a speed of 300 r / min. After ball milling, the powder was dried in an oven at 100 ℃ for 8 h. The dried powder was then placed in a muffle furnace at 1000 ℃ and kept at that temperature for 2 h. The sintered powder was then ground in a mortar and sieved through a 200-mesh sieve to prepare bismuth stannate powder. S3. Strontium titanate powder and bismuth stannate powder were mixed at a molar ratio of 0.97:0.03 and then ball-milled for 12 h with deionized water as the medium at a speed of 300 r / min. After ball milling, the powder was placed in an oven and dried at 100 ℃ for 8 h. The dried powder was then ground in a mortar and sieved through a 200-mesh sieve, and then cold isostatic pressing was performed to form the powder.
[0019] S4. After cold isostatic pressing, high-temperature sintering is carried out at a temperature of 1400 ℃ and held for 3 h.
[0020] Example 3 This embodiment provides a strontium titanate-based dual-temperature self-sensor material and its preparation method for high-temperature power generation devices, specifically following the steps below: S1. Strontium carbonate powder and titanium dioxide powder were mixed in an equimolar ratio and ball-milled for 20 hours with deionized water as the medium at a speed of 300 r / min. After ball milling, the powder was dried in an oven at 100 ℃ for 12 hours. The dried powder was then placed in a muffle furnace at 1180 ℃ and held for 2 hours. The sintered powder was then ground in a mortar and sieved through a 180 mesh to prepare strontium titanate powder. S2. Tin dioxide powder and bismuth trioxide powder were mixed at a molar ratio of 3:1 and ball-milled for 20 h with deionized water as the medium at a speed of 300 r / min. After ball milling, the powder was dried in an oven at 80 ℃ for 12 h. The dried powder was then placed in a muffle furnace at 1100 ℃ and kept at that temperature for 2 h. The sintered powder was then ground in a mortar and sieved through a 180 mesh to prepare bismuth stannate powder. S3. Strontium titanate powder and bismuth stannate powder were mixed at a molar ratio of 0.97:0.03 and then ball-milled for 10 h with deionized water as the medium at a speed of 300 r / min. After ball milling, the powder was placed in an oven at 80 ℃ and dried for 120 h. The dried powder was then ground in a mortar and sieved through a 180 mesh after grinding. Finally, it was formed by cold isostatic pressing.
[0021] S4. After cold isostatic pressing, high-temperature sintering is carried out at a temperature of 1380 ℃ and held for 2 h.
[0022] Figure 1 The graph shows the dielectric constant and dielectric loss of the strontium titanate-based material sintered in Example 3 as a function of frequency at 25°C; Figure 1 It can be seen that at 25℃, as the frequency increases, the dielectric constant of the material remains above 500, and the dielectric loss remains below 0.7.
[0023] Figure 2 The graph shows the dielectric constant and dielectric loss of the strontium titanate-based material sintered in Example 3 as a function of temperature at 100 kHz. Figure 2 As can be seen, at 100 kHz, the dielectric constant of the material remains above 700 as the temperature rises. In the dielectric loss diagram, two peaks appear at 70±3℃, 302±3℃, and 100 kHz. Therefore, the temperature can be sensed in situ based on the strontium titanate-based material.
[0024] It should be stated that these specific embodiments are merely illustrative explanations of the present invention and do not constitute any limitation on the scope of protection of the present invention.
Claims
1. A strontium titanate-based capacitor dielectric material with bimodal temperature characteristics, characterized in that, At a frequency of 100 kHz, its dielectric loss exhibits a bimodal characteristic as a function of temperature, with the peak values corresponding to temperatures of 70±3℃ and 302±3℃, respectively.
2. A method for preparing a strontium titanate-based capacitor dielectric material with bimodal temperature characteristics according to claim 1, characterized in that, Includes the following steps: S1. Strontium carbonate and titanium dioxide are mixed in an equimolar ratio, and then ball-milled, dried, pre-calcined, ground and sieved to obtain strontium titanate powder; S2. Tin dioxide and bismuth trioxide are mixed in a molar ratio of 3:1, and then ball-milled, dried, pre-calcined, ground and sieved to obtain bismuth stannate powder. S3. Strontium titanate and bismuth stannate are mixed in a molar ratio of 0.97:0.03, and then ball-milled, dried, ground and sieved, and cold isostatically pressed into shape. S4. Sinter the formed blank at 1380~1400℃ and hold for 2~3 h to obtain the material.
3. The method for preparing the strontium titanate-based capacitor dielectric material with bimodal temperature characteristics according to claim 2, characterized in that, The ball milling in step S1 is carried out using deionized water or anhydrous ethanol as the medium, at a rotation speed of 300 r / min, for 16~32 h. The pre-firing is carried out in an air sintering atmosphere at a temperature of 1100~1250 ℃ for 2~5 h.
4. The method for preparing the strontium titanate-based capacitor dielectric material with bimodal temperature characteristics according to claim 2, characterized in that, The ball milling in step S2 is carried out using deionized water or anhydrous ethanol as the medium, at a rotation speed of 300 r / min, for 10~20 h. The pre-firing is carried out in an air sintering atmosphere at a temperature of 900~1100 ℃ for 2~5 h.
5. The method for preparing the strontium titanate-based capacitor dielectric material with bimodal temperature characteristics according to claim 2, characterized in that, The ball milling in step S3 is performed using deionized water or anhydrous ethanol as the medium, at a rotation speed of 300 r / min, for 8-12 h.
6. The method for preparing the strontium titanate-based capacitor dielectric material with bimodal temperature characteristics according to claim 2, characterized in that, The drying process described in steps S1, S2 and S3 is carried out at a temperature of 80~120 ℃ for 4~12 h.
7. The method for preparing the strontium titanate-based capacitor dielectric material with bimodal temperature characteristics according to claim 2, characterized in that, The grinding and sieving described in steps S1, S2 and S3 involves grinding the powder in a mortar and then sieving it through a sieve at a mesh size of 160 to 200.
8. The application of a strontium titanate-based capacitor dielectric material with bimodal temperature characteristics as described in claim 1 in capacitors for high-temperature power generation devices.