Use of a block polymer as a high temperature capacitor energy storage material

Abstract

The application relates to an application of a block copolymer as a high-temperature capacitor dielectric material. The block copolymer is an A-B-A triblock structure, wherein the A chain segment is a random copolymer of styrene and alpha-methylene-gamma-butyrolactone, and the B chain segment is an ester flexible chain segment (such as butyl acrylate). The total molecular weight of the polymer is 4-200,000, and the proportion of the B chain segment is less than or equal to 25%. A nano-phase separation structure is formed through RAFT emulsion polymerization, charge migration is inhibited by utilizing an interface deep trap, and the following super-high insulation and energy storage performance at 125 DEG C is realized: the breakdown strength is greater than or equal to 600 MV / m, the dielectric loss tan delta is less than or equal to 0.008 (the frequency is 1 kHz), the energy storage density is 7.9 J / cm 3 , and the efficiency is greater than or equal to 90%. The material has high-temperature stability (10 4 cycles of capacity retention rate > 98%) and processability, and is suitable for high-temperature power system capacitors of new energy vehicles and the like.

Description

Technical Field

[0001] This invention relates to the field of high-temperature capacitor energy storage materials, and more specifically to the application of a block polymer as a high-temperature capacitor energy storage material. Background Technology

[0002] With the rapid development of modern electronic power systems towards miniaturization and high temperature (such as the operating temperature of inverters in new energy vehicles > 125℃), there is an urgent need for flexible dielectric films with high energy density and low loss characteristics. Traditional polystyrene (PSt) is widely used in the field of film capacitors due to its ultra-low loss (tanδ < 0.001) and excellent processability. However, the inherent defects of polystyrene still seriously restrict its application: due to the low dielectric constant (εᵣ) of polystyrene (εᵣ≈2.5), the energy storage density (Ud) of polystyrene films is limited to below 1.2 J / cm³. Furthermore, the carrier migration inside polystyrene materials gradually intensifies with increasing temperature, and the leakage current density surges under high temperature conditions, ultimately causing its energy storage efficiency to plummet to below 40%.

[0003] Currently, numerous modification strategies have been developed to improve the energy storage performance of polystyrene, primarily focusing on increasing the dielectric constant and breakdown strength. Doping the matrix with inorganic nanocomposites is a common and effective method to enhance the dielectric constant. Studies have shown that doping polystyrene with inorganic nanoparticles can increase εᵣ to 4.8. However, this inevitably leads to the agglomeration of large quantities of nanoparticles, resulting in severe electric field distortion within the material. This ultimately causes a dramatic increase in dielectric loss and deterioration in insulation performance, thus limiting its applications. To address the problem of surging dielectric loss, later research shifted from inorganic to organic modification. Researchers introduced polar groups (-CN / -NO2) to achieve high dielectric constants and low losses in styrene-based materials. However, an excessive number of polar groups can increase internal breakdown pathways and lead to uncontrolled leakage current and a surge in losses under high-temperature conditions. In the paper "Polymer dielectrics for high-temperature energy storage: Constructing carrier traps," Luo et al. developed a cyano-containing rigid copolymer (εᵣ~14.1). This approach effectively balanced the high dielectric constant and low loss of styrene-based materials. However, its excessive rigidity caused the film to become brittle and unusable independently. Therefore, to achieve dual regulation of energy storage performance and mechanical properties of styrene-based materials, Luo shifted the strategy to block copolymer structural design in the paper "All-organic polymer dielectrics prepared via optimization of sequential structure of polystyrene-based copolymers." Through sequential structural design of block copolymers, they developed a block copolymer material that combines rigidity and flexibility—styrene-b-11-(4'-cyano-[1,1'-biphenyl]-4-yl)oxy)undecyl methacrylate (PS-b-PCBMA). By introducing flexible segments into a rigid framework, they achieved the goal of ensuring energy storage performance while improving processability. However, the improvement in insulation and energy storage performance was limited, so it could not meet the application requirements of commercial capacitor films under high-temperature conditions.

[0004] In summary, how to simultaneously achieve high-temperature usability (operating temperature > 125℃), excellent energy storage performance (energy storage efficiency > 90%, energy storage density > 5 J / cm3), and good processing performance of materials remains a core scientific bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] This invention relates to the application of block copolymers in dielectric materials for high-temperature capacitors. The block copolymer is an ABA triblock structure, with segment A being a St-co-MeMBL random copolymer and segment B being a BA homopolymer. It is formed into a 20-50 nm nanoscale phase-separated structure through RAFT reversible addition-fragmentation chain transfer emulsion polymerization. This structure suppresses charge migration through deep interfacial traps, achieving ultra-high breakdown strength (≥600 MV / m) and ultra-low loss (tanδ≤0.008@1kHz). At 125℃, the energy storage density reaches 6.17 J / cm³ (90% efficiency), and the capacity retention after 10⁴ cycles is >98%.

[0006] An application of a block polymer as a high-temperature capacitor energy storage material, with an operating temperature up to 125℃, a breakdown strength ≥600 MV / m, an energy storage efficiency ≥90%, and an energy storage density ≥7 J / cm3;

[0007] The block polymer has the general structural formula ABA;

[0008] Segment A is a random copolymer of styrene and another monomer, wherein the monomer is selected from one of α-methylene-γ-valerolactone, methyl methacrylate, vinylpyrrolidone, hydroxyethyl methacrylate, glycidyl methacrylate, methyl methacrylate-acrylonitrile, and hydroxyethyl acrylate.

[0009] Segment B is selected from one of the following: butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl acrylate, dodecyl acrylate, and cyclohexyl acrylate.

[0010] Preferably, the total molecular weight of the block polymer is 160,000, the number average molecular weight of segment A is 60,000 to 65,000, and the molecular weight of segment B is 30,000 to 40,000.

[0011] Preferably, in the block polymer, the weight percentage of MeMBL in segment A is ≤50% and the weight percentage of segment B is ≤25%.

[0012] More preferably, A is a random copolymer of styrene and α-methylene-γ-valerol, and B is one of butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl acrylate, dodecyl acrylate, and cyclohexyl acrylate.

[0013] More preferably, the block polymer is a poly(styrene-co-α-methylene-γ-butyrolactone-b-butyl acrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer, a poly(styrene-co-α-methylene-γ-butyrolactone-b-ethyl acrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer, a poly(styrene-co-α-methylene-γ-butyrolactone-b-butyl methacrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer, or a poly(styrene-co-α-methylene-γ-butyrolactone-b-hydroxyethyl methacrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer.

[0014] Further preferred, the total molecular weight of the block polymer is 160,000, the number average molecular weight of the A segment is 60,000 and 65,000, and the molecular weight of the B segment is 30,000 and 40,000.

[0015] More preferably, the weight percentage of the B segment is ≥18%.

[0016] The experimental data show that the optimal block polymer is poly(styrene-co-α-methylene-γ-butyrolactone-b-butyl acrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer, in which the ratio of St to MeMBL in segment A is 5:5, the mass percentage of butyl acrylate in segment B is 25%, and the total molecular weight is 160,000.

[0017] Using N,N-dimethylformamide (DMF) as a solvent, the block copolymer and DMF were prepared into a homogeneous solution at a solid-liquid ratio of 1:3. After evaporation at 100°C, a novel high-temperature capacitor energy storage film was obtained.

[0018] The surface morphology of the film was observed, and the thickness of the film was measured using a thickness gauge. The standard was that there were no bubbles, the thickness was uniform, and the surface was smooth. A new type of high-temperature capacitor energy storage film that meets the requirements was obtained.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The block polymer of the present invention has excellent insulation properties and advantages such as high energy storage density, wide operating frequency range, wide operating temperature range, and easy processing and manufacturing.

[0021] The block polymer of the present invention can be prepared in a controllable manner, and the molecular chain structure can be arbitrarily adjusted within a certain range to adapt to the requirements of different working conditions.

[0022] The block polymer of this invention exhibits excellent high-temperature performance and good energy storage stability, and can maintain excellent performance under long-term use. Attached Figure Description

[0023] Figure 1 The Wei-bull distribution diagrams are for the high-temperature capacitor energy storage films prepared in comparative examples 1-6.

[0024] Figure 2 Dielectric spectrum of the high-temperature capacitor energy storage film prepared in Examples 1-6 as a comparative example;

[0025] Figure 3 The energy storage performance curves of the high-temperature capacitor energy storage films prepared in Comparative Examples 1-6 are shown.

[0026] Figure 4 Performance statistics of the high-temperature capacitor energy storage films prepared in comparative examples 1-6. Detailed Implementation

[0027] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0028] Example 1: Poly(styrene-co-α-methylene-γ-valerol-b-butyl acrylate-b-styrene-co-α-methylene-γ-valerol) triblock copolymer (St:MeMBL=5:5)

[0029] This embodiment uses the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization method to prepare materials. The specific steps are as follows:

[0030] (1) 50g of ultrapure water, 0.1g of amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent, 1.3071g of styrene and 1.4072g of α-methylene-γ-valerolactone-b-butyl acrylate (MeMBL) were added to a beaker for pre-swelling. After emulsification, the mixture was added to a reaction apparatus, stirred and mixed, and nitrogen was purged to remove oxygen. The mixture was heated to 80°C, and 0.0024g of water-soluble initiator (potassium persulfate, KPS) was added. After initiating polymerization for 1 hour, 0.035g of 10% sodium hydroxide (NaOH) solution was added, and the temperature was raised to 90°C. The first stage of synthesis was completed when the conversion rate reached more than 90%. After the temperature dropped to room temperature, 1.2g of butyl acrylate monomer was slowly added. After pre-swelling for 1 hour, the temperature was raised to 70°C and polymerization continued until the conversion rate reached more than 90%, thus completing the second stage of synthesis. Slowly add 1.3071g St and 1.4072g MeMBL, heat to 90℃, continue polymerization until the conversion rate reaches 90%, and terminate the reaction to obtain the emulsion product.

[0031] (2) Cool the emulsion to room temperature and stir with 3 wt% hydrochloric acid (HCl) solution to break the emulsion. After breaking the emulsion, wash with deionized water until neutral. Place the solid obtained from breaking the emulsion in a fume hood for 48 hours and then place it in a vacuum oven and dry it at 70°C for 24 hours to remove residual moisture and unreacted monomers, to obtain the crude product;

[0032] The block copolymer prepared in this embodiment has a mass ratio of St to MeMBL of 5:5, a molecular weight of butyl acrylate of 30,000, and a total molecular weight of 160,000.

[0033] The solid product prepared above was dissolved in DMF solution at a solid-liquid ratio of 1:3, stirred to obtain a uniform solution, poured into a polytetrafluoroethylene petri dish, and coated into a film using a 30 μm thick doctor blade at a speed of 2 mm / s. The film was heated to 100 °C and then placed in a 40 °C vacuum oven for 24 hours to evaporate, thus obtaining a novel high-temperature capacitor energy storage film.

[0034] Example 2: Poly(styrene-co-α-methylene-γ-valerol-b-butyl acrylate-b-styrene-co-α-methylene-γ-valerol) triblock copolymer (St:MeMBL=6:4)

[0035] This embodiment uses the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization method to prepare materials. The specific steps are as follows:

[0036] (1) 50g of ultrapure water, 0.1g of amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent, 1.58g of styrene, and 1.134g of α-methylene-γ-valerol-b-butyl acrylate (MeMBL) were added to a beaker for pre-swelling. After uniform emulsification, the mixture was added to the reaction apparatus, stirred, and purged with nitrogen to remove oxygen. The mixture was heated to 80°C, and 0.0024g of water-soluble initiator (potassium persulfate, KPS) was added. After initiating polymerization for 1 hour, 0.035g of 10% NaOH solution was added, and the temperature was raised to 90°C. The first stage of synthesis was completed when the conversion rate reached over 90%. After the temperature dropped to room temperature, 1.2g of butyl acrylate monomer was slowly added. After pre-swelling for 1 hour, the temperature was raised to 70°C to continue polymerization until the conversion rate reached over 90%, thus completing the second stage of synthesis. Slowly add 1.58g St and 1.134g MeMBL, heat to 90℃, continue polymerization until the conversion rate reaches 90%, and terminate the reaction to obtain the emulsion product.

[0037] (2) Cool the emulsion to room temperature and stir with 3 wt% HCl solution to break the emulsion. After breaking the emulsion, wash with deionized water until neutral. Place the solid obtained from breaking the emulsion in a fume hood for 48 hours and then place it in a vacuum oven and dry it at 70°C for 24 hours to remove residual moisture and unreacted monomers, to obtain the crude product;

[0038] The block copolymer prepared in this embodiment has a mass ratio of St to MeMBL of 6:4, a molecular weight of butyl acrylate of 30,000, and a total molecular weight of 160,000.

[0039] The solid product prepared above was dissolved in DMF solution at a solid-liquid ratio of 1:3, stirred to obtain a uniform solution, poured into a polytetrafluoroethylene petri dish, and coated into a film using a 30 μm thick doctor blade at a speed of 2 mm / s. The film was heated to 100 °C and then placed in a 40 °C vacuum oven for 24 hours to evaporate, thus obtaining a novel high-temperature capacitor energy storage film.

[0040] Example 3: Poly(styrene-co-α-methylene-γ-valerol-b-butyl acrylate-b-styrene-co-α-methylene-γ-valerol) triblock copolymer (St:MeMBL=7:3)

[0041] This embodiment uses the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization method to prepare materials. The specific steps are as follows:

[0042] (1) 50g of ultrapure water, 0.1g of amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent, 1.8572g of styrene and 0.8568g of α-methylene-γ-valerolactone-b-butyl acrylate (MeMBL) were added to a beaker for pre-swelling. After uniform emulsification, the mixture was added to the reaction apparatus, stirred and mixed, nitrogen was purged to remove oxygen, and the temperature was raised to 80℃. 0.0024g of water-soluble initiator (potassium persulfate, KPS) was added. After initiating polymerization for 1 hour, 0.035g of 10% NaOH solution was added, and the temperature was raised to 90℃. The first stage of synthesis was completed when the conversion rate reached more than 90%. After the temperature dropped to room temperature, 1.2g of monomer butyl acrylate was slowly added. After pre-swelling for 1 hour, the temperature was raised to 70℃ and polymerization continued until the conversion rate reached more than 90%, completing the second stage of synthesis. Slowly add 1.8572g St and 0.8568g MeMBL, heat to 90℃, continue polymerization until the conversion rate reaches 90%, and terminate the reaction to obtain the emulsion product.

[0043] (2) Cool the emulsion to room temperature and stir with 3 wt% HCl solution to break the emulsion. After breaking the emulsion, wash with deionized water until neutral. Place the solid obtained from breaking the emulsion in a fume hood for 48 hours and then place it in a vacuum oven and dry it at 70°C for 24 hours to remove residual moisture and unreacted monomers, to obtain the crude product;

[0044] The block copolymer prepared in this embodiment has a mass ratio of St to MeMBL of 7:3, a molecular weight of butyl acrylate of 30,000, and a total molecular weight of 160,000.

[0045] The solid product prepared above was dissolved in DMF solution at a solid-liquid ratio of 1:3, stirred to obtain a uniform solution, poured into a polytetrafluoroethylene petri dish, and coated into a film using a 30 μm thick doctor blade at a speed of 2 mm / s. The film was heated to 100 °C and then placed in a 40 °C vacuum oven for 24 hours to evaporate, thus obtaining a novel high-temperature capacitor energy storage film.

[0046] Example 4: Poly(styrene-co-α-methylene-γ-valerol-b-butyl acrylate-b-styrene-co-α-methylene-γ-valerol) triblock copolymer (St:MeMBL=5:5)

[0047] This embodiment uses the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization method to prepare materials. The specific steps are as follows:

[0048] (1) 50g of ultrapure water, 0.1g of amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent, 1.2027g of styrene and 1.2949g of α-methylene-γ-valerolactone-b-butyl acrylate (MeMBL) were added to a beaker for pre-swelling. After uniform emulsification, the mixture was added to the reaction apparatus, stirred and mixed, and nitrogen was purged to remove oxygen. The temperature was raised to 80°C, and 0.0024g of water-soluble initiator (potassium persulfate, KPS) was added. After initiating polymerization for 1 hour, 0.035g of 10% NaOH solution was added, and the temperature was raised to 90°C. The first stage of synthesis was completed when the conversion rate reached more than 90%. After the temperature dropped to room temperature, 1.53g of monomer butyl acrylate was slowly added. After pre-swelling for 1 hour, the temperature was raised to 70°C and polymerization was continued until the conversion rate reached more than 90%, thus completing the second stage of synthesis. Slowly add 1.2027g St and 1.2949g MeMBL, heat to 90℃, continue polymerization until the conversion rate reaches 90%, and terminate the reaction to obtain the emulsion product.

[0049] (2) Cool the emulsion to room temperature and stir with 3 wt% HCl solution to break the emulsion. After breaking the emulsion, wash with deionized water until neutral. Place the solid obtained from breaking the emulsion in a fume hood for 48 hours and then place it in a vacuum oven and dry it at 70°C for 24 hours to remove residual moisture and unreacted monomers, to obtain the crude product;

[0050] The block copolymer prepared in this embodiment has a mass ratio of St to MeMBL of 5:5, a molecular weight of butyl acrylate of 40,000, and a total molecular weight of 160,000.

[0051] The solid product prepared above was dissolved in DMF solution at a solid-liquid ratio of 1:3, stirred to obtain a uniform solution, poured into a polytetrafluoroethylene petri dish, and coated into a film using a 30 μm thick doctor blade at a speed of 2 mm / s. The film was heated to 100 °C and then placed in a 40 °C vacuum oven for 24 hours to evaporate, thus obtaining a novel high-temperature capacitor energy storage film.

[0052] Example 5: Poly(styrene-co-α-methylene-γ-valerol-b-butyl acrylate-b-styrene-co-α-methylene-γ-valerol) triblock copolymer (St:MeMBL=6:4)

[0053] This embodiment uses the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization method to prepare materials. The specific steps are as follows:

[0054] (1) 50g of ultrapure water, 0.1g of amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent, 1.454g of styrene, and 1.0437g of α-methylene-γ-valerol-b-butyl acrylate (MeMBL) were added to a beaker for pre-swelling. After uniform emulsification, the mixture was added to a reaction apparatus, stirred, and purged with nitrogen to remove oxygen. The mixture was heated to 80°C, and 0.0024g of water-soluble initiator (potassium persulfate, KPS) was added. After initiating polymerization for 1 hour, 0.035g of 10% NaOH solution was added, and the temperature was raised to 90°C. The first stage of synthesis was completed when the conversion rate reached over 90%. After the temperature dropped to room temperature, 1.53g of butyl acrylate monomer was slowly added. After pre-swelling for 1 hour, the temperature was raised to 70°C to continue polymerization until the conversion rate reached over 90%, thus completing the second stage of synthesis. Slowly add 1.454g St and 1.0437g MeMBL, heat to 90℃, continue polymerization until the conversion rate reaches 90%, and terminate the reaction to obtain the emulsion product.

[0055] (2) Cool the emulsion to room temperature and stir with 3 wt% HCl solution to break the emulsion. After breaking the emulsion, wash with deionized water until neutral. Place the solid obtained from breaking the emulsion in a fume hood for 48 hours and then place it in a vacuum oven and dry it at 70°C for 24 hours to remove residual moisture and unreacted monomers, to obtain the crude product;

[0056] The block copolymer prepared in this embodiment has a mass ratio of St to MeMBL of 6:4, a molecular weight of butyl acrylate of 40,000, and a total molecular weight of 160,000.

[0057] The solid product prepared above was dissolved in DMF solution at a solid-liquid ratio of 1:3, stirred to obtain a uniform solution, poured into a polytetrafluoroethylene petri dish, and coated into a film using a 30 μm thick doctor blade at a speed of 2 mm / s. The film was heated to 100 °C and then placed in a 40 °C vacuum oven for 24 hours to evaporate, thus obtaining a novel high-temperature capacitor energy storage film.

[0058] Example 6: Poly(styrene-co-α-methylene-γ-valerol-b-butyl acrylate-b-styrene-co-α-methylene-γ-valerol) triblock copolymer (St:MeMBL=7:3)

[0059] This embodiment uses the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization method to prepare materials. The specific steps are as follows:

[0060] (1) 50g of ultrapure water, 0.1g of amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent, 1.7092g of styrene and 0.7886g of α-methylene-γ-valerolactone-b-butyl acrylate (MeMBL) were added to a beaker for pre-swelling. After uniform emulsification, the mixture was added to the reaction apparatus, stirred and mixed, nitrogen was purged to remove oxygen, and the temperature was raised to 80℃. 0.0024g of water-soluble initiator (potassium persulfate, KPS) was added, and after initiating polymerization for 1 hour, 0.035g of 10% NaOH solution was added, and the temperature was raised to 90℃. The first stage of synthesis was completed when the conversion rate reached more than 90%. After the temperature dropped to room temperature, 1.53g of monomer butyl acrylate was slowly added. After pre-swelling for 1 hour, the temperature was raised to 70℃ and polymerization continued until the conversion rate reached more than 90%, completing the second stage of synthesis. Slowly add 1.7092g St and 0.7886g MeMBL, heat to 90℃, continue polymerization until the conversion rate reaches 90%, and terminate the reaction to obtain the emulsion product.

[0061] (2) Cool the emulsion to room temperature and stir with 3 wt% HCl solution to break the emulsion. After breaking the emulsion, wash with deionized water until neutral. Place the solid obtained from breaking the emulsion in a fume hood for 48 hours and then place it in a vacuum oven and dry it at 70°C for 24 hours to remove residual moisture and unreacted monomers, to obtain the crude product;

[0062] The block copolymer prepared in this embodiment has a mass ratio of St to MeMBL of 7:3, a molecular weight of butyl acrylate of 40,000, and a total molecular weight of 160,000.

[0063] The solid product prepared above was dissolved in DMF solution at a solid-liquid ratio of 1:3, stirred to obtain a uniform solution, poured into a polytetrafluoroethylene petri dish, and coated into a film using a 30 μm thick doctor blade at a speed of 2 mm / s. The film was heated to 100 °C and then placed in a 40 °C vacuum oven for 24 hours to evaporate, thus obtaining a novel high-temperature capacitor energy storage film.

[0064] Comparative example: Polystyrene homopolymer

[0065] This embodiment uses the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization method to prepare materials. The specific steps are as follows:

[0066] (1) 50g of ultrapure water, 0.1g of amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent, and 6.6086g of styrene were added to a beaker for pre-swelling. After the emulsion was uniform, it was added to the reaction apparatus, stirred and mixed, nitrogen was purged to remove oxygen, and the temperature was raised to 80°C. 0.0024g of water-soluble initiator (potassium persulfate, KPS) was added. After initiating polymerization for 1 hour, 0.035g of 10% NaOH solution was added. The reaction was stopped when the conversion rate reached more than 90% to obtain the emulsion product.

[0067] (2) Cool the emulsion to room temperature and stir with 3 wt% HCl solution to break the emulsion. After breaking the emulsion, wash with deionized water until neutral. Place the solid obtained from breaking the emulsion in a fume hood for 48 hours and then place it in a vacuum oven and dry it at 70°C for 24 hours to remove residual moisture and unreacted monomers, to obtain the crude product;

[0068] The total molecular weight of the polystyrene homopolymer prepared in this embodiment is 160,000.

[0069] The solid product prepared above was dissolved in DMF solution at a solid-liquid ratio of 1:3, stirred to obtain a uniform solution, poured into a polytetrafluoroethylene petri dish, and coated into a film using a 30 μm thick doctor blade at a speed of 2 mm / s. The film was heated to 100 °C and then placed in a 40 °C vacuum oven for 24 hours to evaporate, thus obtaining a novel high-temperature capacitor energy storage film.

Claims

1. An application of a block copolymer as an energy storage material for high-temperature capacitors, characterized in that, The block polymer was prepared and dissolved in DMF solution at a solid-liquid ratio of 1:3 to 1:

10. The solution was stirred to obtain a uniform solution, which was then poured into a polytetrafluoroethylene petri dish. A 30 μm thick doctor blade was used to coat the film at a speed of 2 mm / s. The film was heated to 100°C and then placed in a 40°C vacuum oven for 24 hours to evaporate, resulting in a novel high-temperature capacitor energy storage film. The block polymer has the general structural formula ABA; Segment A is a random copolymer of styrene and another monomer, wherein the monomer is selected from one of α-methylene-γ-valerolactone, methyl methacrylate, vinylpyrrolidone, hydroxyethyl methacrylate, glycidyl methacrylate, methyl methacrylate-acrylonitrile, and hydroxyethyl acrylate. Segment B is selected from one or more of butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl acrylate, dodecyl acrylate, and cyclohexyl acrylate.

2. The application of the block copolymer according to claim 1 as a high-temperature capacitor energy storage material, characterized in that, The total molecular weight of the block polymer is 40,000 to 200,000, the number average molecular weight of segment A is 30,000 to 100,000, and the number average molecular weight of segment B is 10,000 to 100,000.

3. The application of the block copolymer according to claims 1 and 2 as a high-temperature capacitor energy storage material, characterized in that, In the block polymer, the weight percentage of B segments is ≤25%.

4. The application of the block copolymer according to claim 3 as a high-temperature capacitor energy storage material, characterized in that, A is a random copolymer of another monomer of styrene, and the monomer is selected from one of α-methylene-γ-valerolactone, methyl methacrylate, vinylpyrrolidone, hydroxyethyl methacrylate, glycidyl methacrylate, methyl methacrylate-acrylonitrile, and hydroxyethyl acrylate; B is ultimately selected from one of butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl acrylate, dodecyl acrylate, and cyclohexyl acrylate.

5. The application of the block polymer according to claim 4 as a high-temperature capacitor energy storage material, characterized in that, The block polymer is preferably a poly(styrene-co-α-methylene-γ-butyrolactone-b-butyl acrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer, a poly(styrene-co-α-methylene-γ-butyrolactone-b-ethyl acrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer, a poly(styrene-co-α-methylene-γ-butyrolactone-b-butyl methacrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer, or a poly(styrene-co-α-methylene-γ-butyrolactone-b-hydroxyethyl methacrylate-b-styrene-co-α-methylene-γ-butyrolactone) triblock copolymer.

6. The application of the block copolymer according to any one of claims 2 to 5, characterized in that: It can be adapted to capacitor energy storage operation at temperatures above 125℃, with dielectric loss tanδ≤0.008 (@1 kHz), breakdown strength ≥521 MV / m, energy storage density ≥6.17 J / cm³, and charge / discharge efficiency ≥90%.

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