A long cycle life high stability super capacitor for building and a preparation method thereof

Abstract

This invention relates to the field of capacitor technology, specifically disclosing a long-cycle-life, high-stability supercapacitor for buildings and its preparation method. The supercapacitor includes an electrode assembly, an inorganic salt aqueous electrolyte, and a waterproof and shock-resistant encapsulation shell. The electrode assembly includes a positive electrode, a negative electrode, and a separator. Both the positive and negative electrodes are dry-type self-supporting electrodes, and the separator is disposed between the positive and negative electrodes. The dry-type self-supporting electrode includes a dry-type self-supporting electrode film, a metal current collector, and a high-temperature varistor conductive adhesive layer disposed between the dry-type self-supporting electrode film and the metal current collector. A neutral inorganic salt aqueous electrolyte is used in conjunction with activated carbon active material to achieve purely physical double-layer energy storage without the generation of chemical reaction byproducts. A stable three-dimensional electrode skeleton structure is constructed through fibrosis treatment of a surface-modified polymer binder. The electrode film has a room temperature tensile strength ≥2.5 MPa, an elongation at break ≥15%, and a tensile strength retention rate ≥85% after 1000 cycles at temperatures ranging from -40℃ to 85℃.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, specifically to a long-cycle-life, high-stability supercapacitor for building applications and its preparation method. Summary of the Invention

[0002] To address the shortcomings of existing technologies, this invention provides a long-cycle-life, high-stability supercapacitor for buildings and its fabrication method, thus solving the problems mentioned in the background technology.

[0003] To achieve the above objectives, the present invention provides the following technical solution: a long cycle life and high stability supercapacitor for building applications, comprising an electrode assembly, an inorganic salt aqueous electrolyte, and a waterproof and shockproof encapsulation shell; The electrode assembly includes a positive electrode, a negative electrode, and a separator. The positive electrode and the negative electrode are both dry-type self-supporting electrodes, and the separator is disposed between the positive electrode and the negative electrode. The dry self-supporting electrode includes a dry self-supporting electrode film, a metal current collector, and a high-temperature varistor conductive adhesive layer disposed between the dry self-supporting electrode film and the metal current collector. The dry self-supporting electrode membrane is formed by combining activated carbon active material and surface modified polymer binder after fiberization treatment, and the dry self-supporting electrode membrane contains composite conductive agent added in stages and gradients. The high-temperature pressure-sensitive conductive adhesive layer is composed of a pressure-sensitive polymer adhesive matrix with temperature response characteristics and a composite conductive filler. The pressure-sensitive polymer adhesive matrix is ​​configured to be non-sticky at room temperature (25°C), have storage stability of ≥6 months, and soften and produce pressure-sensitive adhesion when heated to 80~160°C. Under heating and pressurization conditions, the high-strength interfacial composite between the dry self-supporting electrode film and the metal current collector is achieved. The inorganic salt aqueous electrolyte is a neutral inorganic salt water system, which is matched with the activated carbon active material to achieve pure physical double-layer energy storage. The supercapacitor has a cycle life of ≥100,000 cycles and a capacity decay rate of ≤10%, which is suitable for the energy storage needs of buildings with a design life of more than 50 years.

[0004] Preferably, the surface-modified polymeric binder is obtained by modifying at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polymethyl vinyl carbonate (PMVC) with surface functional groups and synergistically modifying it with conductive polymers. The surface functional group modification is achieved by grafting at least one polar functional group selected from carboxyl, hydroxyl, and sulfonic acid groups onto the polymer adhesive molecular chain, with a grafting rate of 2% to 15%. The conductive polymer synergistic modification involves compounding at least one conductive polymer, either polyaniline (PANI) or polypyrrole (PPy), into the modified polymer binder, wherein the mass of the conductive polymer accounts for 3% to 20% of the total mass of the modified polymer binder. In the dry self-supporting electrode film, the mass percentages of each component are as follows: 80%~95% activated carbon active material, 3%~12% surface-modified polymer binder, and 2%~8% composite conductive agent.

[0005] Preferably, the degree of fibrosis of the dry self-supporting electrode film is measured by a fibrosis index. Quantitative characterization, the fibrosis index The value is determined by both the process parameters and material properties during the fiberization process, and satisfies the following calculation formula: ; In the formula: The fiberization index is a dimensionless index used to characterize the degree of fiberization in modified polymer adhesives, with a value ranging from 0.50 to 0.95. Shear rate during the fiberization stage, in units of The value range is 50~500 ; The total time for fiber shearing treatment, in units of ; It is a time index, dimensionless, with a value range of 0.5 to 1.5, and corresponds one-to-one with the types of modified polymer adhesives; These are equipment constants related to the mixing equipment, dimensionless, and obtained in advance from the structural parameters of the internal mixer / mixing equipment; Modified polymer binders at fiberization treatment temperature The apparent viscosity is given below, in units of , The value range is 80~200℃; The fiber index Porosity of dry self-supporting electrode films Satisfying the linear correlation formula enables precise and controllable porosity: ; In the formula: The basic porosity of the unfiberized mixture. The porosity attenuation coefficient is dimensionless; the porosity of the electrode film... Ultimately, the concentration is controlled at 35%~65% to meet the requirements of rapid wetting and ion transport in inorganic salt aqueous electrolytes.

[0006] Preferably, the intrinsic in-plane conductivity of the dry self-supporting electrode film is... ,tensile strength Both are related to the fibrosis index There is a quantitative correlation, enabling synergistic regulation of the degree of fibrosis and electrode performance; The intrinsic surface conductivity The correlation formula is ; In the formula: The intrinsic in-plane conductivity of the independent electrode film without current collector recombination at 25℃ is given in units of... The four-probe method was used for testing, and the value was ≥0.5. ; The basic electrical conductivity of the unfiberized mixed powder is expressed in units of... ; This is the conductivity enhancement factor, in units of... The value ranges from 0.1 to 2.0. The electrode film exhibits a conductivity fluctuation rate of ≤15% within the entire building temperature range of -40℃ to 85℃, and a conductivity retention rate of ≥90% after 100,000 cycles. The tensile strength The correlation formula is: ; In the formula: Tensile strength at room temperature, in units of The tensile test was conducted using a universal tensile tester, and the value was ≥2.5. ; Fiberization Index The basic tensile strength at that time, in units of ; The fiber reinforcement factor is expressed in units of 1000 ppm. The value ranges from 1.0 to 8.0. ; To enhance the index, it is dimensionless and ranges from 1.2 to 2.5; the elongation at break of the electrode film is ≥15%, and the tensile strength retention rate is ≥85% after 1000 cycles at temperatures from -40℃ to 85℃.

[0007] Preferably, the composite conductive agent is composed of at least two of the following: zero-dimensional conductive carbon black (SP), one-dimensional carbon nanotubes, and two-dimensional graphene. Furthermore, the composite conductive agent is added in at least three stages during the fibrosis process, with the specific gradient rule as follows: Phase 1, Fibrinization Index When the concentration reaches 0.20~0.35, add 30%~50% of zero-dimensional conductive carbon black SP, which accounts for 30%~50% of the total mass of the composite conductive agent. Second stage, fibrosis index When the concentration reaches 0.40~0.60, add 20%~40% one-dimensional carbon nanotubes of the total mass of the composite conductive agent; The third stage, fibrosis index When the concentration reaches 0.65~0.80, add 10%~30% of two-dimensional graphene by mass of the total composite conductive agent; The composite conductive agent added in stages and gradients forms a three-dimensional continuous conductive network within the electrode film, consisting of zero-dimensional point contact, one-dimensional line connection, and two-dimensional surface conduction. This solves the problems of uneven dispersion and easy collapse of the conductive network caused by the one-time addition of conductive agent in existing technologies.

[0008] Preferably, the volume resistivity of the high-temperature varistor conductive adhesive layer is... Total interfacial resistance All meet the quantitative calculation formula, achieving a balanced control of the conductivity and adhesive performance of the adhesive layer; The volume resistivity Volume fraction of composite conductive filler Satisfying the correlation formula of seepage theory: ; In the formula: The volume resistivity of the adhesive layer, in units of The value is ≤1.0×10 -2 ; The volume resistivity of the pure pressure-sensitive polymer binder matrix is ​​expressed in units of... ; The efficiency constant for the formation of the conductive path is dimensionless and ranges from 2.0 to 6.0. The volume fraction of the composite conductive filler is dimensionless. The permeation threshold of the conductive filler is dimensionless and ranges from 0.02 to 0.08; the volume fraction of the composite conductive filler is... satisfy ; The total interface resistance The calculation formula is: ; In the formula: The total interfacial resistance of the adhesive layer, in units of ; This refers to the thickness of the adhesive layer, in units of... The value range is 2 to 10. ,and ≤1 / 8 of the thickness of the dry self-supporting electrode film; Effective bonding area, in units of ; Interface contact resistance, unit: ; through control and ,make The resistance is ≤15% of the total internal resistance of the electrode, and the interface resistance growth rate is ≤20% after 100,000 cycles, with no interface peeling phenomenon.

[0009] Preferably, the pressure-sensitive polymer adhesive matrix is ​​at least one of modified acrylate copolymer, modified polyurethane, and modified polyolefin, and its glass transition temperature is... The temperature range is -20℃ to 10℃, and the softening temperature is 70℃ to 150℃. The softening temperature is lower than the melting temperature of the modified polymer binder, so as to avoid damaging the fibrous structure of the electrode film during hot pressing. The room temperature peel strength of the high-temperature varistor conductive adhesive layer is ≤0.1. Peel strength ≥15 under 120℃ heating and pressure The pressure-sensitive polymer binder matrix, after being immersed in an inorganic salt aqueous electrolyte for 1000 hours, exhibits a mass change rate of ≤2% and shows no swelling or degradation.

[0010] Preferably, the inorganic salt aqueous electrolyte is a neutral aqueous solution of at least one selected from sodium sulfate, lithium sulfate, and potassium chloride, with a concentration of 0.5~2.0%. The pH value is 6-8; The waterproof and shockproof enclosure is made of aluminum alloy or stainless steel, with a protection level of ≥IP67 and a seismic resistance level of ≥8, making it suitable for various building service environments. The supercapacitor, after undergoing needle penetration, compression, and short circuit tests when fully charged, showed no fire or explosion, meeting the intrinsic safety requirements for building energy storage.

[0011] A method for fabricating a long-cycle-life, high-stability supercapacitor for building applications includes the following steps: Step S1: Polymer binder modification treatment, the polymer binder is modified by grafting surface functional groups and composited with conductive polymer to obtain surface modified polymer binder; Step S2: Premix preparation: Activated carbon active material and surface modified polymer binder are premixed at low temperature and low shear according to the ratio to obtain a uniform premix. Step S3: Staged fiberization and gradient conductive agent addition; high-shear fiberization treatment of the premix at elevated temperature; real-time monitoring and closed-loop control of the fiberization index. ,according to Different dimensions of composite conductive agents are added in three stages to obtain a fibrous electrode mixture; Step S4: Dry self-supporting electrode film forming. The fibrous electrode mixture is extruded, calendered in multiple passes, calendered to a fixed thickness, wound up and tested online to obtain a dry self-supporting electrode film. Step S5: Current collector pretreatment and adhesive layer coating. The surface of the metal current collector is roughened and passivated. A high-temperature pressure-sensitive conductive adhesive layer slurry is coated and dried at low temperature to obtain a current collector with an adhesive layer. Step S6: High-temperature composite of electrode film and current collector. Align and stack the electrode film with the current collector with adhesive layer, and perform segmented hot pressing composite to obtain dry electrode sheet. Step S7: Electrode assembly assembly and packaging. The positive and negative electrode sheets and the separator are stacked / wound to form an electrode assembly, which is then installed into the packaging shell and sealed by laser welding. Step S8: Electrolyte injection and formation. Inorganic salt aqueous electrolyte is injected, and after vacuum settling, staged constant current and constant voltage formation is carried out. After completion, leak detection and electrical performance testing are performed to obtain the finished supercapacitor.

[0012] Preferably, in step S2, the premixing temperature is room temperature to 60°C, and the shear rate is 10 to 50. Mixing time: 10-30 minutes; In step S3, the fibrillation index is calculated in real time using a formula. By dynamically adjusting the shear rate, temperature, and processing time through PID closed-loop control, The stability is controlled within the range of 0.50~0.95; the specific process for adding the conductive agent in stages is as follows: When the concentration reaches 0.20~0.35, add the first part of conductive carbon black and mix for 5~15 minutes; When the concentration reaches 0.40~0.60, add the second part of carbon nanotubes and mix for 8~20 minutes; When the concentration reaches 0.65~0.80, add the third part of graphene and mix for 3~10 minutes until... The target range has been achieved; In step S3, the fiberization treatment temperature is 80~200℃, and the shear rate is 50~500. Total processing time: 30-120 minutes; In step S4, the rolling process consists of 3 to 8 passes, with a rolling temperature of 60 to 150°C and an electrode film thickness of 50 to 300 mm. Thickness deviation ≤ ±3%; The segmented hot-pressing composite process in step S6 is as follows: the first stage is preheating at 60~100℃ and 0.5~2MPa for 10~30s; the second stage is hot pressing at 100~160℃ and 3~10MPa for 20~60s; and the third stage is holding pressure at 2~5MPa and cooling down to below 40℃ for 10~20s. The phased formation process in step S8 is as follows: constant current and constant voltage charging is performed in three gradient voltage stages. After each stage is completed, the battery is left to stand for 30 to 120 minutes, and then constant current discharge is performed. This charge-discharge cycle is repeated 3 to 5 times to complete the formation.

[0013] This invention provides a long-cycle-life, high-stability supercapacitor for building applications and its preparation method, which has the following beneficial effects: 1. This invention uses a neutral inorganic salt aqueous solution electrolyte matched with activated carbon active material to achieve purely physical double-layer energy storage without the generation of chemical reaction byproducts. Through the fibrous treatment of surface-modified polymer binder, a stable three-dimensional electrode skeleton structure is constructed. The electrode film has a room temperature tensile strength ≥2.5MPa, an elongation at break ≥15%, and a tensile strength retention rate ≥85% after 1000 cycles at temperatures ranging from -40℃ to 85℃. At the same time, an innovative high-temperature pressure-sensitive conductive adhesive layer is used to achieve high-strength interfacial composite between the electrode film and the current collector. After 100,000 cycles, the interfacial resistance growth rate is ≤20%, with no interfacial delamination. The final supercapacitor has a cycle life ≥100,000 cycles and a capacity decay rate ≤10%, fully meeting the design service life requirements of buildings for more than 50 years.

[0014] 2. This invention completely eliminates safety hazards at the system level by using a neutral inorganic salt aqueous solution electrolyte with no risk of combustion or explosion to replace the traditional organic electrolyte; the matching waterproof and shockproof encapsulation shell has a protection rating of ≥IP67 and a seismic resistance rating of ≥8. After undergoing extreme tests such as needle penetration, compression, and short circuit in a fully charged state, the supercapacitor shows no signs of fire or explosion, meeting the intrinsic safety standards for building energy storage.

[0015] 3. By adding zero-dimensional conductive carbon black, one-dimensional carbon nanotubes, and two-dimensional graphene in stages and gradients, a three-dimensional continuous conductive network with zero-dimensional point contact, one-dimensional line connection, and two-dimensional surface conduction is formed within the electrode film. The intrinsic in-plane conductivity of the electrode film is ≥0.5 S / cm. Within the entire building temperature range of -40℃ to 85℃, the conductivity fluctuation of the electrode film is ≤15%, and the conductivity retention rate is ≥90% after 100,000 cycles, enabling stable operation in buildings in various climatic regions of my country.

[0016] 3. This invention introduces the fibrosis index (FI) as a core control parameter in electrode preparation for the first time, establishing a quantitative correlation formula between FI and electrode film porosity, conductivity, and tensile strength. Through PID closed-loop control, the shear rate, temperature, and processing time are dynamically adjusted to achieve precise and controllable electrode performance. The segmented hot-pressing composite process and the staged formation process are simple and easy to operate, compatible with existing building material production lines, and significantly reduce the cost of large-scale production.

[0017] 4. The electrode preparation process adopts a completely dry method, which does not use organic solvents at all, thus avoiding the emission of toxic and harmful substances and the cost of environmental treatment; the electrode material is mainly inexpensive and readily available activated carbon, without the need to use scarce metals such as lithium, cobalt, and nickel. The preparation process is green and low-carbon, which meets the development requirements of green building.

[0018] 5. The supercapacitor of this invention can efficiently store redundant power generated during peak periods of building-integrated photovoltaic (BIPV) systems and release it during peak electricity demand periods, effectively mitigating peak-valley electricity price differences and reducing daily electricity costs for buildings. Simultaneously, its ultra-long cycle life avoids multiple replacements throughout its lifespan, significantly reducing equipment replacement and maintenance costs. Large-scale deployment of the supercapacitors of this invention on the building side can effectively mitigate peak-valley loads on the power grid, reduce power supply pressure during peak load periods, lower infrastructure investment for grid expansion and upgrades, and improve the overall operating efficiency of the power grid. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the process for preparing a long-cycle-life, high-stability supercapacitor for building applications according to the present invention. Figure 2 Illustration of conductive modification of adhesive; Figure 3 The graph shows the correlation between the fibrillation index (FI) and the electrode membrane performance. Figure 4 Schematic diagram of a phased gradient addition process for composite conductive agents; Figure 5 This is a characteristic curve of the high-temperature varistor conductive adhesive layer; Figure 6 This is a parameter curve diagram for the segmented hot-pressing composite process; Figure 7 This is a comparison chart of the cycle life performance of supercapacitors. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] The overall fabrication process of the supercapacitor described in this invention is as follows: Figure 1 As shown, the process mainly includes eight core steps: modification of polymer binders, preparation of premixes, staged fiberization and addition of gradient conductive agents, dry self-supporting electrode film forming, current collector pretreatment and adhesive layer coating, high-temperature composite of electrode film and current collector, electrode assembly and packaging, and electrolyte injection and formation.

[0022] This invention discloses a building-side supercapacitor with long cycle life and high stability, aiming to solve the technical problems of existing supercapacitors, such as short cycle life, poor stability, and insufficient safety, which prevent them from being suitable for the design service life of buildings exceeding 50 years. This supercapacitor employs a purely physical double-layer energy storage mechanism, achieving ultra-long cycle life and high environmental adaptability through dry self-supporting electrode technology, high-temperature varistor conductive bonding technology, and gradient conductive network construction technology. It also possesses advantages such as intrinsic safety, environmental friendliness, and low cost, making it particularly suitable for building-side energy storage scenarios such as building-integrated photovoltaic energy storage, emergency power supplies, and grid peak shaving.

[0023] The long cycle life and high stability building supercapacitor of the present invention is mainly composed of three parts: electrode assembly, inorganic salt aqueous electrolyte, and waterproof and shockproof encapsulation shell.

[0024] The electrode assembly includes a positive electrode, a negative electrode, and a separator. The positive and negative electrodes employ identical dry-process self-supporting electrode structures. The separator is positioned between the positive and negative electrodes to prevent direct contact and short circuits while allowing ions in the electrolyte to pass freely. The separator can be made of polypropylene (PP), polyethylene (PE), or a composite separator thereof, with a thickness of 10–30 μm and a porosity of 40%–60%.

[0025] The dry self-supporting electrode comprises a dry self-supporting electrode film, a metal current collector, and a high-temperature varistor conductive adhesive layer disposed between the dry self-supporting electrode film and the metal current collector. The metal current collector can be made of aluminum foil, copper foil, or stainless steel foil, with a thickness of 8~20μm, and its surface is roughened and passivated to improve the adhesion with the adhesive layer.

[0026] The inorganic salt aqueous electrolyte is a neutral inorganic salt water system, which, when matched with activated carbon active material, achieves pure physical double-layer energy storage without the generation of chemical reaction byproducts, fundamentally avoiding the risk of combustion and explosion and the corrosiveness of traditional organic electrolytes.

[0027] The waterproof and shockproof enclosure is made of aluminum alloy or stainless steel and is sealed by laser welding. It has a protection level of ≥IP67 and a shock resistance level of ≥8, and can adapt to the complex service environment in the construction field, including humidity, vibration, and temperature changes.

[0028] The dry-process self-supporting electrode membrane is formed by composite of activated carbon active material and surface-modified polymer binder after fibrosis treatment, and the electrode membrane contains a composite conductive agent added in stages and gradients. The mass percentages of each component are: activated carbon active material 80%~95%, surface-modified polymer binder 3%~12%, and composite conductive agent 2%~8%.

[0029] The activated carbon material can be coconut shell activated carbon, coal-based activated carbon, or pitch-based activated carbon, with a specific surface area of ​​1500~3000 m². 2 / g, the pore size distribution is mainly mesopores of 2~5nm, accounting for more than 60% of the total pore volume, which can provide sufficient double-layer energy storage sites and ensure rapid ion transport.

[0030] The surface-modified polymeric binder is obtained by surface functional group modification and synergistic modification with conductive polymers from at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polymethyl vinyl carbonate (PMVC); the surface functional group grafting and conductive polymer composite modification process of the binder is as follows: Figure 2 As shown, by introducing polar functional groups and doping conductive polymers onto the polymer backbone, the interfacial bonding force and intrinsic conductivity of the binder are simultaneously improved.

[0031] Among them, surface functional group modification involves grafting at least one polar functional group, such as carboxyl, hydroxyl, or sulfonic acid groups, onto the polymer binder molecular chain, with a grafting rate of 2% to 15%, which can improve the interfacial bonding force between the binder and activated carbon particles; conductive polymer synergistic modification involves compounding at least one conductive polymer, such as polyaniline (PANI) or polypyrrole (PPy), into the modified polymer binder, with the mass of the conductive polymer accounting for 3% to 20% of the total mass of the modified polymer binder, which can improve the conductivity of the binder itself and reduce the internal resistance of the electrode.

[0032] The degree of fiberization of the dry-process self-supporting electrode film is quantitatively characterized by the fiberization index FI. The fiberization index FI is determined by both process parameters and material property parameters during the fiberization process, and satisfies the following calculation formula: ; In the formula: The fiberization index is a dimensionless index used to characterize the degree of fiberization in modified polymer adhesives, with a value ranging from 0.50 to 0.95. Shear rate during the fiberization stage, in units of The value range is 50~500 ; The total time for fiber shearing treatment, in units of ; It is a time index, dimensionless, with a value range of 0.5 to 1.5, and corresponds one-to-one with the types of modified polymer adhesives; These are equipment constants related to the mixing equipment, dimensionless, and obtained in advance from the structural parameters of the internal mixer / mixing equipment; Modified polymer binders at fiberization treatment temperature The apparent viscosity is given below, in units of , The value range is 80~200℃.

[0033] The fibrillation index FI and the porosity of the dry self-supporting electrode film are related. Satisfying the linear correlation formula enables precise and controllable porosity: ; In the formula: The basic porosity of the unfiberized mixture; The porosity attenuation coefficient is dimensionless; the porosity of the electrode film... Ultimately, the concentration is controlled at 35%~65% to meet the requirements of rapid wetting and ion transport in inorganic salt aqueous electrolytes.

[0034] Meanwhile, the intrinsic in-plane conductivity of the dry self-supporting electrode film ,tensile strength All of these parameters are quantitatively correlated with the fibrillation index (FI), enabling synergistic regulation of the degree of fibrillation and electrode performance. Formula for intrinsic in-plane conductivity: ; In the formula: The intrinsic in-plane conductivity of the independent electrode film without current collector recombination at 25℃ is given in units of... The four-probe method was used for testing, and the value was ≥0.5. ; The basic electrical conductivity of the unfiberized mixed powder is expressed in units of... ; This is the conductivity enhancement factor, in units of... The value ranges from 0.1 to 2.0. The electrode film exhibits a conductivity fluctuation rate of ≤15% within the entire building temperature range of -40℃ to 85℃, and a conductivity retention rate of ≥90% after 100,000 cycles.

[0035] Tensile strength correlation formula: ; In the formula: Tensile strength at room temperature, in units of The tensile test was conducted using a universal tensile tester, and the value was ≥2.5. ; Fiberization Index The basic tensile strength at that time, in units of ; The fiber reinforcement factor is expressed in units of 1000 ppm. The value ranges from 1.0 to 8.0. ; To enhance the index, it is dimensionless and ranges from 1.2 to 2.5; the elongation at break of the electrode film is ≥15%, and after 1000 cycles at -40℃ to 85℃, the tensile strength retention rate is ≥85%. Fiberization index. The quantitative correlation between electrode film porosity, intrinsic in-plane conductivity, and room temperature tensile strength is as follows: Figure 3 As shown, the preferred FI value range of this invention is 0.50~0.95. Within this range, the electrode film can simultaneously meet the performance requirements of porosity 35%~65%, conductivity ≥0.5S / cm, and tensile strength ≥2.5MPa.

[0036] The composite conductive agent is composed of at least two of the following: zero-dimensional conductive carbon black (SP), one-dimensional carbon nanotubes, and two-dimensional graphene. Furthermore, the composite conductive agent is added in a gradient manner during the fibrosis process in at least three stages, with the specific gradient rule as follows: Phase 1, Fibrinization Index When the concentration reaches 0.20~0.35, add 30%~50% of zero-dimensional conductive carbon black SP, which accounts for 30%~50% of the total mass of the composite conductive agent. Second stage, fibrosis index When the concentration reaches 0.40~0.60, add 20%~40% one-dimensional carbon nanotubes of the total mass of the composite conductive agent; The third stage, fibrosis index When the concentration reaches 0.65~0.80, add 10%~30% of two-dimensional graphene by mass of the total composite conductive agent.

[0037] By adding conductive agents of different dimensions in stages and gradients, a three-dimensional continuous conductive network consisting of zero-dimensional point contact, one-dimensional line connection, and two-dimensional surface conduction can be formed within the electrode film. This effectively solves the problems of uneven dispersion and easy collapse of the conductive network caused by the one-time addition of conductive agents in existing technologies, and significantly improves the conductivity and cycle stability of the electrode. The specific process of adding composite conductive agents in stages and gradients is as follows: Figure 4 As shown, with the gradual increase in the degree of fiberization, zero-dimensional, one-dimensional, and two-dimensional conductive materials are introduced in sequence, and finally a complete three-dimensional conductive pathway is constructed on the modified binder fiber skeleton.

[0038] The high-temperature pressure-sensitive conductive adhesive layer is composed of a pressure-sensitive polymer adhesive matrix with temperature-responsive characteristics and a composite conductive filler. The pressure-sensitive polymer adhesive matrix is ​​configured to be non-sticky at room temperature (25°C), have a storage stability of ≥6 months, and soften and exhibit pressure-sensitive adhesion when heated to 80~160°C, achieving a high-strength interfacial composite between the dry self-supporting electrode film and the metal current collector under heating and pressurization conditions.

[0039] The pressure-sensitive polymer adhesive matrix is ​​at least one of modified acrylate copolymer, modified polyurethane, and modified polyolefin, and its glass transition temperature is... The temperature range is -20℃ to 10℃, and the softening temperature is 70℃ to 150℃. The softening temperature is lower than the melting point of the modified polymer binder, thus preventing damage to the fibrous structure of the electrode film during hot pressing. After immersion in an inorganic salt aqueous electrolyte for 1000 hours, the pressure-sensitive polymer binder matrix exhibits a mass change rate of ≤2%, with no swelling or degradation, demonstrating excellent electrolyte stability.

[0040] The composite conductive filler may be at least one of conductive carbon black, carbon nanotubes, graphene, and graphite powder, with a volume fraction of satisfy ,in The permeation threshold of the conductive filler is 0.02 to 0.08.

[0041] The volume resistivity of the high-temperature varistor conductive adhesive layer Volume fraction of composite conductive filler Satisfying the correlation formula of seepage theory: ; In the formula: The volume resistivity of the adhesive layer, in units of The value is ≤1.0×10 -2 ; The volume resistivity of the pure pressure-sensitive polymer binder matrix is ​​expressed in units of... ; The efficiency constant for the formation of the conductive path is dimensionless and ranges from 2.0 to 6.0.

[0042] The total interfacial resistance of the high-temperature varistor conductive adhesive layer The following calculation formula must be satisfied: ; In the formula: The total interfacial resistance of the adhesive layer, in units of ; This refers to the thickness of the adhesive layer, in units of... The value range is 2 to 10. ,and ≤1 / 8 of the thickness of the dry self-supporting electrode film; Effective bonding area, in units of ; Interface contact resistance, unit: .

[0043] By controlling the volume fraction of the composite conductive filler and adhesive layer thickness This can reduce the total interfacial resistance of the adhesive layer. The interface resistance is ≤15% of the total internal resistance of the electrodes, and the interface resistance growth rate after 100,000 cycles is ≤20%, with no interface peeling. The room temperature peel strength of the high-temperature varistor conductive adhesive layer is ≤0.1. Easy to transport and store; peel strength ≥15 under 120℃ heating and pressure. This ensures a strong bond between the electrode film and the current collector during long-term cycling. The temperature-peel strength and conductive permeation characteristics of the high-temperature pressure-sensitive conductive adhesive layer are as follows: Figure 5 As shown, it exhibits non-stickiness at room temperature, strong adhesion within the hot-pressing temperature range of 80~160℃, and excellent conductivity can be obtained when the volume fraction of conductive filler is controlled within the range of 0.02~0.35.

[0044] The inorganic salt aqueous electrolyte is a neutral aqueous solution of at least one of sodium sulfate, lithium sulfate, and potassium chloride, with a concentration of 0.5~2.0%. The pH value is 6-8. This electrolyte has advantages such as high conductivity, low viscosity, no risk of combustion or explosion, and no corrosiveness. When matched with activated carbon active materials, it can achieve pure physical double-layer energy storage without the generation of chemical reaction byproducts, thereby significantly improving the cycle life and safety of supercapacitors.

[0045] Specific examples of preparation methods: Example 1: This example provides a method for fabricating a long-cycle-life, high-stability supercapacitor for building applications. The specific steps are as follows: Step S1: Polymer binder modification treatment: 100g of polytetrafluoroethylene (PTFE) powder was added to an ethanol solution containing 5g of acrylic monomer and 0.5g of benzoyl peroxide initiator. The mixture was reacted at 80℃ for 4 hours under nitrogen protection to perform carboxyl grafting modification, with a grafting rate of 8%. Then, 10g of polyaniline (PANI) powder was added, and the mixture was stirred for another 2 hours to perform conductive polymer synergistic modification, resulting in a surface-modified PTFE binder.

[0046] Step S2: Premix preparation: Weigh out activated carbon active material (specific surface area 2000 m²) at a mass ratio of 90:7:3. 2 / g), the above-mentioned surface-modified PTFE binder and composite conductive agent (conductive carbon black: carbon nanotubes: graphene = 4:3.5:2.5). Activated carbon and modified PTFE binder were added to an internal mixer and subjected to a 30°C process. Premix at the shear rate for 20 min to obtain a homogeneous premix.

[0047] Step S3: Staged fiberization and gradient conductive agent addition: Heat the premix to 120°C and adjust the shear rate to 200. The material undergoes fiberization treatment. The fiberization index is calculated in real-time using the aforementioned formula. The value is dynamically adjusted through PID closed-loop control of process parameters: when When the concentration reaches 0.25, add conductive carbon black accounting for 40% of the total mass of the composite conductive agent and mix for 10 minutes. when When the concentration reaches 0.50, add carbon nanotubes accounting for 35% of the total mass of the composite conductive agent and mix for 15 minutes. when When the concentration reaches 0.70, add graphene accounting for 25% of the total mass of the composite conductive agent and mix for 5 minutes. Continue the fiberization process until the total time reaches 60 minutes, finally. The value stabilized at 0.75, resulting in a fibrous electrode mixture.

[0048] Step S4: Dry self-supporting electrode film molding: The fibrous electrode mixture was fed into a twin-screw extruder for extrusion, and then calendered in a five-pass calender at 100℃ to obtain a dry-process self-supporting electrode film with a thickness of 150 μm and a thickness deviation of ≤±2%. Testing showed that the electrode film had a porosity of 52% and an intrinsic in-plane conductivity of 0.8. The room temperature tensile strength is 3.2. The elongation at break is 18%.

[0049] Step S5: Current collector pretreatment and adhesive layer coating: A 12μm thick aluminum foil was subjected to surface roughening treatment (roughness Ra=0.8μm) and passivation treatment. A high-temperature pressure-sensitive conductive adhesive layer slurry was prepared by mixing modified acrylate copolymer and conductive carbon black at a mass ratio of 85:15 (conductive filler volume fraction). =0.15), dispersed in deionized water, with a solid content of 30%. The slurry was coated onto the surface of the pretreated aluminum foil and dried at a low temperature of 80℃ to obtain a current collector with an adhesive layer and a thickness of 5μm.

[0050] Step S6: High-temperature composite of electrode film and current collector: The dry self-supporting electrode film is aligned and stacked with the current collector with an adhesive layer, and then fed into a hot press for segmented hot pressing composite: First section: 80℃, 1 Preheat for 20 seconds; Second section: 120℃, 5 Hot pressing for 40 seconds; Third paragraph: 3 Hold the pressure and cool down to below 30℃ for 15 seconds; A dry-process electrode sheet was obtained. The interfacial peel strength of this electrode sheet was tested to be 18. The total interface resistance is 8 The temperature and pressure change curves of the segmented hot-pressing composite process are as follows: Figure 6 As shown, the three-stage gradient heating and pressurization process, followed by pressure holding and cooling, ensures the full softening and adhesion of the adhesive layer while avoiding damage to the fibrous structure of the electrode film caused by high temperature and high pressure.

[0051] Step S7: Electrode assembly and packaging: The aforementioned dry-process electrode sheets were cut into 10cm × 10cm positive and negative electrode sheets, and alternately stacked with a polypropylene separator to form an electrode assembly. The electrode assembly was then installed in an aluminum alloy casing and sealed using laser welding technology, with a weld strength ≥ 20. .

[0052] Step S8: Electrolyte injection and formation: Inject 1 into the package housing The electrodes were subjected to a neutral sodium sulfate electrolyte (pH=7.0) and allowed to stand under vacuum for 24 hours to allow the electrolyte to fully wet the electrodes. Then, a staged constant current and constant voltage formation process was performed. Phase 1: Starting with 1 Charge the current to 0.8. Constant pressure 30 Let stand for 60 minutes , with 1 Current discharged to 0 ; Phase Two: With 1 Charge the current to 1.2. Constant pressure 30 Let stand for 60 minutes , with 1 Current discharged to 0 ; Phase Three: With 1 The current is charged to 1.6. Constant pressure 60 Let stand for 60 minutes , with 1 Current discharged to 0 ; The above charge-discharge cycle was repeated four times to complete the formation. Finally, leak detection and electrical performance testing were performed to obtain the finished supercapacitor.

[0053] Example 2, the difference between this example and Example 1 is: The polymer binder is made of polyvinylidene fluoride (PVDF) with hydroxyl groups grafted onto the surface at a grafting rate of 5%, and is composed of polypyrrole (PPy) at a content of 15%. The mass ratio of activated carbon, modified PVDF binder, and composite conductive agent is 88:9:3; The fiberization treatment temperature is 150℃, and the shear rate is 300. The total processing time was 80 minutes, and finally... The value is 0.80; The electrolyte used is 1.5 Lithium sulfate aqueous solution; The second stage of hot-pressing composite is carried out at a temperature of 130℃ and a pressure of 6. The hot pressing time is 35 minutes. .

[0054] The remaining steps are the same as in Example 1. Testing showed that the electrode film prepared in this example had a porosity of 48% and an intrinsic in-plane conductivity of 0.9. The room temperature tensile strength is 3.5. The initial capacitance of the supercapacitor is 120. The capacity decay rate after 100,000 cycles is 8.5%.

[0055] Example 3, the difference between this example and Example 1 is: The polymer binder is made of polymethyl vinyl carbonate (PMVC) with sulfonic acid groups grafted onto its surface at a grafting rate of 12%, and is composed of polyaniline and polypyrrole (mass ratio 1:1) with a total content of 5%. The mass ratio of activated carbon, modified PMVC binder, and composite conductive agent is 92:5:3; The fiberization treatment temperature is 100℃, and the shear rate is 150. The total processing time was 50 minutes, and finally... The value is 0.65; The electrolyte used is 2.0. Aqueous solution of potassium chloride; The second stage of hot-pressing composite is at a temperature of 110℃ and a pressure of 4. The hot pressing time is 45 minutes. .

[0056] The remaining steps are the same as in Example 1. Testing showed that the electrode film prepared in this example had a porosity of 56% and an intrinsic in-plane conductivity of 0.7. The room temperature tensile strength is 2.8. The initial capacitance of the supercapacitor is 115. The capacity decay rate after 100,000 cycles is 9.2%.

[0057] Performance testing and comparative analysis: To verify the technical effect of the present invention, performance tests were conducted on the supercapacitors prepared in the above embodiments and the comparative sample prepared using conventional techniques. The test results are shown in the table below: ; ; Note: Comparative Example 1 uses the traditional wet electrode process, with NMP as solvent and PVDF as binder, and the conductive agent is added in one step; Comparative Example 2 uses the dry electrode film of the present invention, but uses ordinary epoxy resin conductive adhesive as the bonding layer; Comparative Example 3 uses the dry electrode process and high temperature varistor conductive bonding layer of the present invention, but adds all composite conductive agents in one step.

[0058] The cycle life performance comparison curves of the embodiments of the present invention and the comparative sample are as follows: Figure 7 As shown, after 100,000 charge-discharge cycles, the capacity retention rate of the embodiments of the present invention is above 90%, which is far superior to the technical solutions of traditional wet electrodes, ordinary adhesive layers and one-time addition of conductive agents.

[0059] The test results show that: The supercapacitors prepared in the embodiments of the present invention have a cycle life of ≥100,000 cycles and a capacity decay rate of ≤10%, which is far superior to traditional wet electrode and ordinary adhesive layer technology, and can meet the design service life requirements of buildings of more than 50 years. The dry self-supporting electrode film of the present invention has higher tensile strength and temperature stability. After 1000 cycles at temperatures ranging from -40℃ to 85℃, the strength retention rate is ≥85%, which can adapt to the complex temperature environment in the construction field. The phased gradient addition of conductive agents significantly improves the conductivity and cycling stability of the electrodes, with conductivity retention ≥90% after 100,000 cycles; High-temperature varistor conductive adhesive layer technology effectively reduces interface resistance, and the interface resistance increases slowly during long-term cycling, with no interface peeling phenomenon. The supercapacitor of this invention, which uses a neutral inorganic salt aqueous solution as electrolyte, has passed extreme safety tests such as needle penetration and compression, without any fire or explosion, and possesses intrinsic safety.

[0060] The long-cycle-life, high-stability supercapacitor for building applications and its preparation method provided in this invention have the following beneficial effects: Ultra-long cycle life: It adopts a pure physical double-layer energy storage mechanism with no chemical reaction byproducts; a stable three-dimensional electrode skeleton structure is constructed through the fiberization treatment of surface-modified polymer adhesive, and a high-strength interface composite is achieved with a high-temperature pressure-sensitive conductive adhesive layer, so that the supercapacitor has a cycle life of ≥100,000 times and a capacity decay rate of ≤10%, which fully meets the design service life requirements of buildings of more than 50 years.

[0061] High environmental adaptability: The conductivity fluctuation rate of the electrode film is ≤15% in the entire building temperature range of -40℃ to 85℃, and the tensile strength retention rate is ≥85% after 1000 temperature cycles; the waterproof and shockproof encapsulation shell has a protection level of ≥IP67 and a seismic resistance level of ≥8, enabling it to work stably in buildings in various climate regions of my country.

[0062] Intrinsic safety: The electrolyte is a neutral inorganic salt solution with no risk of combustion or explosion, instead of the traditional organic electrolyte. The supercapacitor does not ignite or explode after undergoing extreme tests such as needle penetration, compression, and short circuit when fully charged, which meets the intrinsic safety standards for building energy storage.

[0063] Green and environmentally friendly: The electrode preparation process adopts a completely dry method, which does not use organic solvents at all, thus avoiding the emission of toxic and harmful substances and the cost of environmental treatment; the electrode material is mainly inexpensive and readily available activated carbon, without the need to use scarce metals such as lithium, cobalt, and nickel. The preparation process is green and low-carbon, which meets the development requirements of green building.

[0064] Low cost: The segmented hot-pressing composite process and the staged formation process are simple and easy to operate, and can be compatible with existing building material production lines, significantly reducing the cost of large-scale production; the ultra-long cycle life avoids multiple replacements throughout the entire life cycle, significantly reducing equipment replacement and maintenance costs.

[0065] High application value: The supercapacitor of this invention can efficiently store redundant power generated during peak periods of building photovoltaic systems and release it during peak electricity consumption periods, effectively easing the peak-valley electricity price difference and reducing the daily electricity cost of buildings; large-scale deployment of the supercapacitor of this invention on the building side can effectively smooth the peak-valley load of the power grid, reduce the power supply pressure during peak load periods, reduce infrastructure investment for power grid expansion and upgrades, and improve the overall operating efficiency of the power grid.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A building supercapacitor with long cycle life and high stability, characterized in that, Includes electrode components, inorganic salt aqueous electrolyte, and waterproof and shockproof encapsulation housing; The electrode assembly includes a positive electrode, a negative electrode, and a separator. The positive electrode and the negative electrode are both dry-type self-supporting electrodes, and the separator is disposed between the positive electrode and the negative electrode. The dry self-supporting electrode includes a dry self-supporting electrode film, a metal current collector, and a high-temperature varistor conductive adhesive layer disposed between the dry self-supporting electrode film and the metal current collector. The dry self-supporting electrode membrane is formed by combining activated carbon active material and surface modified polymer binder after fiberization treatment, and the dry self-supporting electrode membrane contains composite conductive agent added in stages and gradients. The high-temperature pressure-sensitive conductive adhesive layer is composed of a pressure-sensitive polymer adhesive matrix with temperature response characteristics and a composite conductive filler. The pressure-sensitive polymer adhesive matrix is ​​configured to be non-sticky at room temperature (25°C), have storage stability of ≥6 months, and soften and produce pressure-sensitive adhesion when heated to 80~160°C. Under heating and pressurization conditions, the high-strength interfacial composite between the dry self-supporting electrode film and the metal current collector is achieved. The inorganic salt aqueous electrolyte is a neutral inorganic salt water system, which is matched with the activated carbon active material to achieve pure physical double-layer energy storage. The supercapacitor has a cycle life of ≥100,000 cycles and a capacity decay rate of ≤10%, which is suitable for the energy storage needs of buildings with a design life of more than 50 years.

2. The long-cycle-life, high-stability supercapacitor for buildings according to claim 1, characterized in that, The surface-modified polymeric binder is obtained by modifying at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polymethyl vinyl carbonate (PMVC) with surface functional groups and synergistically modifying it with conductive polymers. The surface functional group modification is achieved by grafting at least one polar functional group selected from carboxyl, hydroxyl, and sulfonic acid groups onto the polymer adhesive molecular chain, with a grafting rate of 2% to 15%. The conductive polymer synergistic modification involves compounding at least one conductive polymer, either polyaniline (PANI) or polypyrrole (PPy), into the modified polymer binder, wherein the mass of the conductive polymer accounts for 3% to 20% of the total mass of the modified polymer binder. In the dry self-supporting electrode film, the mass percentages of each component are as follows: 80%~95% activated carbon active material, 3%~12% surface-modified polymer binder, and 2%~8% composite conductive agent.

3. The long-cycle-life, high-stability supercapacitor for buildings according to claim 2, characterized in that, The degree of fibrosis in the dry self-supporting electrode film is measured by the fibrosis index. Quantitative characterization, the fibrosis index The value is determined by both the process parameters and material properties during the fiberization process, and satisfies the following calculation formula: ； In the formula: The fiberization index is a dimensionless index used to characterize the degree of fiberization in modified polymer adhesives, with a value ranging from 0.50 to 0.

95. Shear rate during the fiberization stage, in units of The value range is 50~500 ; The total time for fiber shearing treatment, in units of ; It is a time index, dimensionless, with a value range of 0.5 to 1.5, and corresponds one-to-one with the types of modified polymer adhesives; These are equipment constants related to the mixing equipment, dimensionless, and obtained in advance from the structural parameters of the internal mixer / mixing equipment; Modified polymer binders at fiberization treatment temperature The apparent viscosity is given below, in units of , The value range is 80~200℃; The fiber index Porosity of dry self-supporting electrode films Satisfying the linear correlation formula enables precise and controllable porosity: ； In the formula: The basic porosity of the unfiberized mixture. The porosity attenuation coefficient is dimensionless; the porosity of the electrode film... Ultimately, the concentration is controlled at 35%~65% to meet the requirements of rapid wetting and ion transport in inorganic salt aqueous electrolytes.

4. The long-cycle-life, high-stability supercapacitor for buildings according to claim 3, characterized in that, Intrinsic in-plane conductivity of the dry self-supporting electrode film ,tensile strength Both are related to the fibrosis index There is a quantitative correlation, enabling synergistic regulation of the degree of fibrosis and electrode performance; The intrinsic surface conductivity The correlation formula is ； In the formula: The intrinsic in-plane conductivity of the independent electrode film without current collector recombination at 25℃ is given in units of... The four-probe method was used for testing, and the value was ≥0.

5. ; The basic electrical conductivity of the unfiberized mixed powder is expressed in units of... ; This is the conductivity enhancement factor, in units of... The value ranges from 0.1 to 2.

0. The electrode film exhibits a conductivity fluctuation rate of ≤15% within the entire building temperature range of -40℃ to 85℃, and a conductivity retention rate of ≥90% after 100,000 cycles. The tensile strength The correlation formula is: ； In the formula: Tensile strength at room temperature, in units of The tensile test was conducted using a universal tensile tester, and the value was ≥2.

5. ; Fiberization Index The basic tensile strength at that time, in units of ; The fiber reinforcement factor is expressed in units of 1000 ppm. The value ranges from 1.0 to 8.

0. ; To enhance the index, it is dimensionless and ranges from 1.2 to 2.5; the elongation at break of the electrode film is ≥15%, and the tensile strength retention rate is ≥85% after 1000 cycles at temperatures from -40℃ to 85℃.

5. A building supercapacitor with long cycle life and high stability according to claim 4, characterized in that, The composite conductive agent is composed of at least two of the following: zero-dimensional conductive carbon black (SP), one-dimensional carbon nanotubes, and two-dimensional graphene. Furthermore, the composite conductive agent is added in a gradient manner during the fibrosis process in at least three stages, with the specific gradient rule as follows: Phase 1, Fibrinization Index When the concentration reaches 0.20~0.35, add 30%~50% of zero-dimensional conductive carbon black SP, which accounts for 30%~50% of the total mass of the composite conductive agent. Second stage, fibrosis index When the concentration reaches 0.40~0.60, add 20%~40% one-dimensional carbon nanotubes of the total mass of the composite conductive agent; The third stage, fibrosis index When the concentration reaches 0.65~0.80, add 10%~30% of two-dimensional graphene by mass of the total composite conductive agent; The composite conductive agent added in stages and gradients forms a three-dimensional continuous conductive network within the electrode film, consisting of zero-dimensional point contact, one-dimensional line connection, and two-dimensional surface conduction.

6. The long-cycle-life, high-stability supercapacitor for buildings according to claim 5, characterized in that, The volume resistivity of the high-temperature varistor conductive adhesive layer Total interfacial resistance All meet the quantitative calculation formula, achieving a balanced control of the conductivity and adhesive performance of the adhesive layer; The volume resistivity Volume fraction of composite conductive filler Satisfying the correlation formula of seepage theory: ； In the formula: The volume resistivity of the adhesive layer, in units of The value is ≤1.0×10 -2 ; The volume resistivity of the pure pressure-sensitive polymer binder matrix is ​​expressed in units of... ; The efficiency constant for the formation of the conductive path is dimensionless and ranges from 2.0 to 6.

0. The volume fraction of the composite conductive filler is dimensionless. The permeation threshold of the conductive filler is dimensionless and ranges from 0.02 to 0.08; the volume fraction of the composite conductive filler is... satisfy ; The total interface resistance The calculation formula is: ； In the formula: The total interfacial resistance of the adhesive layer, in units of ; This refers to the thickness of the adhesive layer, in units of... The value range is 2 to 10. ,and ≤1 / 8 of the thickness of the dry self-supporting electrode film; Effective bonding area, in units of ; Interface contact resistance, unit: ; through control and ,make The resistance is ≤15% of the total internal resistance of the electrode, and the interface resistance growth rate is ≤20% after 100,000 cycles, with no interface peeling phenomenon.

7. A building supercapacitor with long cycle life and high stability according to claim 6, characterized in that, The pressure-sensitive polymer adhesive matrix is ​​at least one of modified acrylate copolymer, modified polyurethane, and modified polyolefin, and its glass transition temperature is... The temperature range is -20℃ to 10℃, and the softening temperature is 70℃ to 150℃. The softening temperature is lower than the melting temperature of the modified polymer binder, so as to avoid damaging the fibrous structure of the electrode film during hot pressing. The room temperature peel strength of the high-temperature varistor conductive adhesive layer is ≤0.

1. Peel strength ≥15 under 120℃ heating and pressure The pressure-sensitive polymer binder matrix, after being immersed in an inorganic salt aqueous electrolyte for 1000 hours, exhibits a mass change rate of ≤2% and shows no swelling or degradation.

8. A building supercapacitor with long cycle life and high stability according to claim 7, characterized in that, The inorganic salt aqueous electrolyte is a neutral aqueous solution of at least one of sodium sulfate, lithium sulfate, and potassium chloride, with a concentration of 0.5~2.0%. The pH value is 6~8.

9. The method for preparing a long-cycle-life, high-stability supercapacitor for buildings according to claim 8, characterized in that, Includes the following steps: Step S1: Polymer binder modification treatment, the polymer binder is modified by grafting surface functional groups and composited with conductive polymer to obtain surface modified polymer binder; Step S2: Premix preparation: Activated carbon active material and surface modified polymer binder are premixed at low temperature and low shear according to the ratio to obtain a uniform premix. Step S3: Staged fiberization and gradient conductive agent addition; high-shear fiberization treatment of the premix at elevated temperature; real-time monitoring and closed-loop control of the fiberization index. ,according to Different dimensions of composite conductive agents are added in three stages to obtain a fibrous electrode mixture; Step S4: Dry self-supporting electrode film forming. The fibrous electrode mixture is extruded, calendered in multiple passes, calendered to a fixed thickness, wound up and tested online to obtain a dry self-supporting electrode film. Step S5: Current collector pretreatment and adhesive layer coating. The surface of the metal current collector is roughened and passivated. A high-temperature pressure-sensitive conductive adhesive layer slurry is coated and dried at low temperature to obtain a current collector with an adhesive layer. Step S6: High-temperature composite of electrode film and current collector. Align and stack the electrode film with the current collector with adhesive layer, and perform segmented hot pressing composite to obtain dry electrode sheet. Step S7: Electrode assembly assembly and packaging. The positive and negative electrode sheets and the separator are stacked / wound to form an electrode assembly, which is then installed into the packaging shell and sealed by laser welding. Step S8: Electrolyte injection and formation. Inorganic salt aqueous electrolyte is injected, and after vacuum settling, staged constant current and constant voltage formation is carried out. After completion, leak detection and electrical performance testing are performed to obtain the finished supercapacitor.

10. The method for preparing a long-cycle-life, high-stability supercapacitor for buildings according to claim 9, characterized in that, In step S2, the premixing temperature is room temperature to 60°C, and the shear rate is 10 to 50. Mixing time: 10-30 minutes; In step S3, the fibrillation index is calculated in real time using a formula. By dynamically adjusting the shear rate, temperature, and processing time through PID closed-loop control, The stability is controlled within the range of 0.50~0.95; the specific process for adding the conductive agent in stages is as follows: When the concentration reaches 0.20~0.35, add the first part of conductive carbon black and mix for 5~15 minutes; When the concentration reaches 0.40~0.60, add the second part of carbon nanotubes and mix for 8~20 minutes; When the concentration reaches 0.65~0.80, add the third part of graphene and mix for 3~10 minutes until... The target range has been achieved; In step S3, the fiberization treatment temperature is 80~200℃, and the shear rate is 50~500. Total processing time: 30-120 minutes; In step S4, the rolling process consists of 3 to 8 passes, with a rolling temperature of 60 to 150°C and an electrode film thickness of 50 to 300 mm. Thickness deviation ≤ ±3%; The segmented hot-pressing composite process in step S6 is as follows: the first stage is preheating at 60~100℃ and 0.5~2MPa for 10~30s; the second stage is hot pressing at 100~160℃ and 3~10MPa for 20~60s; and the third stage is holding pressure at 2~5MPa and cooling down to below 40℃ for 10~20s. The phased formation process in step S8 is as follows: constant current and constant voltage charging is performed in three gradient voltage stages. After each stage is completed, the battery is left to stand for 30 to 120 minutes, and then constant current discharge is performed. This charge-discharge cycle is repeated 3 to 5 times to complete the formation.

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