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CN-122011633-A - Preparation method of giant dielectric constant ceramic/PVDF composite material

CN122011633ACN 122011633 ACN122011633 ACN 122011633ACN-122011633-A

Abstract

A preparation method of a giant dielectric constant ceramic/PVDF composite material comprises the steps of preparing CCTO powder by a solid phase method or a sol-gel method, coating and modifying SiO 2 by a st-Baer method, and compounding with PVDF matrix by solution casting to prepare a thick film by different volume fractions (0.5% -4%). Experimental results show that the composite material effectively combines the high dielectric property of CCTO and the excellent mechanical property of PVDF, has optimal comprehensive performance when the volume fraction of CCTO is 2%, has the energy storage density of 4.39J/cm 3 when SiO 2 is not coated, is improved to 5.91J/cm 3 after SiO 2 is coated, has the advantages of high dielectric constant and low dielectric loss, effectively solves the problem of insufficient energy storage performance of a single material, and provides practical reference for development of the field of dielectric energy storage.

Inventors

  • ZHAO XINXIN
  • WANG BO
  • XU CONGZHE
  • WANG HAOKUN
  • ZHANG YIRUI
  • YAO JINGYI
  • ZHANG JIE

Assignees

  • 陕西科技大学

Dates

Publication Date
20260512
Application Date
20260206

Claims (8)

  1. 1. A giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material is characterized in that PVDF is used as a polymer matrix, siO 2 is used for coating and modifying CaCu 3 Ti 4 O 12 (CCTO) as a filler, and the volume fraction of the CCTO is 0.5% -4%.
  2. 2. A method for preparing a giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material, which is characterized by comprising the following steps: (1) Preparing pure-phase CCTO powder by a sol-gel method, and coating and modifying the CCTO powder by a st ber method with SiO 2 to obtain CCTO@SiO 2 filler with excellent dispersibility and interface compatibility; (2) Weighing PVDF and N, N-Dimethylformamide (DMF) according to a proportion, stirring until PVDF is completely dissolved, adding CCTO@Si 2 filler with different volume fractions, stirring, performing ultrasonic dispersion treatment, and standing to obtain uniform composite slurry; (3) The composite slurry is made into thick film by solution casting method, and the high performance ceramic/PVDF composite material with giant dielectric constant, low dielectric loss, high breakdown field strength and high energy storage density is finally obtained by drying, vacuum heating, ice water annealing and stripping processes.
  3. 3. The preparation method of the giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material according to claim 2, wherein the specific process for preparing the CCTO powder by the sol-gel method in the step (1) comprises the steps of preparing solution A by Ti (OC 4 H 9 ) 4 、C 2 H 5 OH、CH 3 COOH, preparing solution B by Cu(NO 3 ) 2 ·H 2 O、Ca(NO 3 ) 3 ·4H 2 O、H2O、C 2 H 5 OH, dripping the solution B at the rate of 1 drop/2 seconds, stirring, aging 24-48 and h to obtain gel, drying and grinding at 60-90 ℃, and calcining at 750-950 ℃ to obtain the nano-scale CCTO powder at 10-15 h.
  4. 4. The preparation method of the giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material according to claim 2, wherein the specific process of SiO 2 coating modification in the step (1) comprises the steps of dispersing 300-400 mesh CCTO powder in a mixed solution of isopropanol and deionized water, adding 30% ammonium hydroxide to adjust the pH value, dropwise adding tetraethyl orthosilicate (TEOS) at the rate of 0.5-3 mu l/min, performing ultrasonic dispersion of 0.5-5 min and stirring of 1-5 min once every dropwise adding, aging 5-10 h, centrifuging, washing until the pH= 7,80-120 ℃ and drying to obtain CCTO@SiO 2 filler.
  5. 5. The method for preparing a giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material according to claim 2, wherein the preparation parameters of the composite slurry in the step (2) are that 0.5-2 g PVDF is dissolved in 5-20 ml DMF, stirred for 4 hours until the composite slurry is completely dissolved, added with 0.5-4% by volume of CCTO@SiO 2 filler, stirred for 30-60 min, then dispersed for 30-60 min by ultrasonic wave, and the process is repeated for 3-6 times, and standing for 10-15 h to eliminate bubbles.
  6. 6. The preparation method of the giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material according to claim 2, wherein the preparation process parameters of the thick film in the step (3) are that after the film is formed by adopting a tape casting method, the thick film is dried in an airless oven at 80-120 ℃, and then is placed into a vacuum drying oven at 180-240 ℃ for vacuum heating for 5-10 min, and is taken out, then is placed into ice water for annealing, and is peeled off to obtain the CCTO/PVDF composite thick film.
  7. 7. The method for preparing a giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material according to claim 2, wherein when the CCTO volume fraction is 2%, the composite material has optimal comprehensive performance, the energy storage density reaches 4.39J/cm 3 when SiO 2 is not coated, the energy storage density is increased to 5.91J/cm 3 after SiO 2 coating, the dielectric constant reaches 17 at maximum at room temperature of 50Hz, and the dielectric loss is maintained at a lower level.
  8. 8. The ceramic/PVDF composite material prepared by the preparation method of the giant dielectric constant ceramic/polyvinylidene fluoride (PVDF) composite material according to any one of claims 2-7 is characterized in that the core performance bright point is giant dielectric constant, low dielectric loss, high breakdown field intensity and high energy storage density, which are coordinated to reach standards, can meet the development requirements of miniaturization, light weight and high energy storage of electronic equipment, and provides a high-performance material solution for the field of dielectric energy storage.

Description

Preparation method of giant dielectric constant ceramic/PVDF composite material Technical Field The invention relates to the technical field of energy storage materials, and particularly discloses a preparation method of a giant dielectric constant ceramic/PVDF composite material with high dielectric constant, low dielectric loss, high breakdown field strength and high energy storage density as core performance targets, which is matched with severe application requirements of miniaturization, light weight and high energy storage of electronic equipment. Background Currently, dielectric energy storage materials are largely divided into three categories, ceramic materials, polymeric materials, and polymer matrix composites. The ceramic material has the defects of poor processability, insufficient flexibility and the like although having a high dielectric constant, and the polymer material such as polyvinylidene fluoride (PVDF) has good mechanical property and processability, but has a relatively low dielectric constant, and is difficult to meet the high energy storage requirement when being singly used. The ceramic filler is compounded with the polymer matrix, so that complementary advantages can be realized. CaCu 3Ti4O12 (CCTO) is used as a typical giant dielectric material, has a dielectric constant of up to 10 4-105 at room temperature, has stable performance in a wide temperature range, and is an ideal composite filler. However, in the process of preparing the CCTO/PVDF composite material, the problems of uneven dispersion of CCTO powder, poor compatibility with a PVDF matrix interface, high dielectric loss, insufficient breakdown field intensity and the like exist, so that the energy storage performance of the composite material is difficult to realize breakthrough improvement. Therefore, the CCTO/PVDF composite material preparation method capable of realizing the synergistic optimization of high dielectric constant, low dielectric loss, high breakdown field strength and high energy storage density is developed, and the method has important practical significance and application value. Disclosure of Invention The invention aims to provide a preparation method of a giant dielectric constant ceramic/PVDF composite material, which overcomes the defects of poor dispersion, poor interface compatibility, insufficient performance cooperativity and the like of CCTO powder in the traditional process, realizes the cooperative optimization of the composite material with high dielectric constant, low dielectric loss, high breakdown field strength and high energy storage density, and provides a high-efficiency and feasible technical scheme for preparing high-performance energy storage capacitors. In order to achieve the above purpose, the present invention adopts the following technical scheme: A giant dielectric constant ceramic/PVDF composite material is characterized in that the giant dielectric constant CCTO ceramic powder is used as a filler, PVDF is used as a polymer matrix to be compounded, the volume fraction of the CCTO ceramic powder in the composite material is 0.5% -4%, and the surface of the CCTO ceramic powder is coated and modified by SiO 2. The composite material has the high dielectric property of CCTO and the excellent mechanical property of PVDF, and has the core advantages of synchronously having high dielectric constant, low dielectric loss, high breakdown field strength and high energy storage density, and adapting to the application requirements of various high energy storage capacitors. And the preparation method of the giant dielectric constant ceramic/PVDF composite material comprises the following steps: preparing pure phase CCTO powder by adopting a sol-gel method, wherein the specific process comprises the steps of preparing solution A by Ti (OC 4H9)4、C2H5OH、CH3 COOH), preparing solution B by Cu(NO3)2·H2O、Ca(NO3)3·4H2O、H2O、C2H5OH, dripping the solution A into the solution B at a rate of 1 drop/2 seconds, stirring, ageing 24-48 and h to obtain gel, drying and grinding at 60-90 ℃, and calcining at 750-950 ℃ for 10-15 h to obtain the nano-scale CCTO powder. And 2, carrying out SiO 2 coating modification on the CCTO powder by a st method to obtain the CCTO@SiO 2 filler with excellent dispersibility and interface compatibility. The preparation method comprises the specific processes of dispersing 300-400 mesh CCTO powder in a mixed solution of isopropanol and deionized water, adding 30% ammonium hydroxide to adjust the pH value, dripping tetraethyl orthosilicate (TEOS) at the rate of 0.5-3 mu l/min, performing ultrasonic dispersion of 0.5-5 min and stirring of 1-5 min once per dripping, aging 5-10 h, centrifuging, washing with water until the pH value is= 7,80-120 ℃, and drying to obtain the CCTO@SiO 2 filler. And 3, dissolving 0.5-2 g PVDF into 5-20 ml DMF, stirring for 4 hours until the solution is completely dissolved, adding 0.5-4% of CCTO@SiO 2 filler by volume fraction, stirring for 30-6