Super capacitor battery based on graphene composite material
Through innovative design of graphene-transition metal oxide composite materials and polymer-inorganic ion gel electrolyte, the problems of low energy density, poor cycle stability and insufficient safety of supercapacitors have been solved, realizing a high-performance electrochemical energy storage device.
Patent Information
- Application Number
- CN202510735124.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-04
- Publication Date
- 2025-11-21
AI Technical Summary
Existing supercapacitors suffer from problems such as low energy density of electrode materials, poor cycle stability, insufficient safety and environmental adaptability of electrolytes, limited structural functions, and difficulty in balancing fast-charging performance and long-term durability.
A graphene-transition metal oxide heterocomposite material, combined with a polymer-inorganic ion composite gel electrolyte, was used to design a triple-layer or vertically aligned graphene sheet electrode structure. Low-temperature reduction and screen printing processes were employed to optimize the electrode-electrolyte interface and encapsulation materials.
It achieves an energy density of ≥40Wh/kg, a power density of ≥5kW/kg, a cycle life of ≥10,000 cycles, adapts to extreme environments, and supports fast charging and flexible device applications.
Smart Images
Figure CN120998692A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical energy storage device technology, and more specifically, to a supercapacitor battery based on graphene composite material. Background Technology
[0002] Supercapacitors, as a novel energy storage device, have shown great potential in fields such as electric vehicle start-stop and power grid frequency regulation due to their high power density and ultra-long cycle life. However, traditional supercapacitors rely on the double-layer energy storage mechanism, and the electrode energy density, mainly composed of carbon-based materials such as activated carbon, is generally below 10 Wh / kg, severely limiting their potential to replace batteries. In existing technologies, researchers have attempted to enhance pseudocapacitance contributions by introducing transition metal oxides (such as MnO2 and RuO2) or conductive polymers (such as polyaniline), but these methods are prone to volume expansion and dissolution of active materials (such as MnO2) during charge and discharge. 3 The disproportionation reaction causes the cycle life to plummet to below 5000 cycles. In addition, although carbonate-based organic electrolytes can increase the voltage window (≥3V), they pose safety hazards due to their flammability and explosiveness, while the defects of water-based electrolytes, such as easy freezing at low temperatures and easy evaporation at high temperatures, further limit their application scenarios.
[0003] The existing technology has the following problems:
[0004] 1. Limitations of electrode material properties and preparation process
[0005] Existing supercapacitor electrode materials (such as activated carbon and traditional transition metal oxides) suffer from low energy density and poor cycle stability (capacity decay rate > 20%). Although graphene has a high specific surface area, it is prone to stacking, which reduces the number of active sites. Transition metal oxides (such as MnO2) are prone to structural collapse during charge and discharge, and traditional preparation processes such as high-temperature reduction and CVD methods are energy-intensive and have low loading rates, significantly increasing production costs.
[0006] 2. Insufficient safety and environmental adaptability of the electrolyte.
[0007] While mainstream organic electrolytes such as carbonates support high voltages (≥3V), they are flammable and explosive, and prone to thermal runaway at high temperatures. Meanwhile, water-based electrolytes are prone to freezing at low temperatures and evaporation at high temperatures, while ionic liquids are too expensive. Existing technologies struggle to balance high safety with wide-temperature stability, limiting their application in extreme environments or flexible equipment.
[0008] 3. Limited structural function and difficulties in system integration
[0009] Traditional supercapacitor electrodes serve only as independent energy storage units, lacking mechanical strength or multifunctional characteristics. For example, metal current collectors account for 15%-30% of the electrode mass and cannot be directly used as structural components, resulting in wasted space. Furthermore, the electrode-electrolyte interface impedance is high (torsivity ≥5), and ion diffusion efficiency is low, leading to a sharp drop in power density during high-rate charge and discharge.
[0010] 4. It is difficult to balance fast charging performance with long-term durability.
[0011] Existing technologies experience accelerated electrolyte decomposition and intensified electrode polarization during high-rate charge and discharge, leading to a significant reduction in cycle life. Furthermore, humidity-sensitive materials (such as LiPF6 electrolyte) are prone to hydrolysis and failure in humid environments, while rigid packaging designs struggle to adapt to the bending requirements of wearable devices, further limiting the expansion of application scenarios.
[0012] Therefore, a supercapacitor battery based on graphene composite materials is proposed to address the above problems. Summary of the Invention
[0013] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a supercapacitor battery based on graphene composite material to solve the problems mentioned in the background art.
[0014] To achieve the above objectives, the present invention provides the following technical solution: a supercapacitor battery based on graphene composite material, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein:
[0015] The positive electrode contains a graphene-based composite material, which is formed by heterogeneous assembly or hydrothermal synthesis of graphene and transition metal oxides (such as Ni-Co layered double hydroxides, T-Nb2O5, Mn3O4 or Ni(OH)2), and is doped with nitrogen and sulfur elements to enhance electrochemical activity.
[0016] The negative electrode is composed of porous carbon material and conductive polymer, with a porosity of 30%-99% and a specific surface area of 450-3000 m². 2 / g;
[0017] The electrolyte is an ionic liquid or a water-based alkaline polymer gel containing KOH, NaOH or LiOH, and the electrolyte decomposition voltage is ≥3V.
[0018] Preferably, the mass ratio of graphene to transition metal oxide in the positive electrode composite material is 1:5-1:40, and a nanoporous structure with a diameter of 0.002-1 μm is formed between the graphene sheets. Sulfur or metal oxide particles are coated in the graphene network to inhibit the loss of active materials.
[0019] Preferably, the porous carbon material of the negative electrode is combined with the conductive polymer through electrostatic self-assembly. The conductive polymer is selected from polyaniline, polypyrrole or poly3,4-ethylenedioxythiophene, and the mass percentage is 5%-20%.
[0020] Preferably, conductive agent and binder are added to the active materials of both the positive and negative electrodes, with a mass ratio of active material: conductive agent: binder = 70-90%: 5-20%: 5-15%.
[0021] Preferably, the electrolyte is a polymer-inorganic ion composite gel, which is formed by mixing and curing polyvinyl alcohol, polyacrylic acid and KOH solution, with the polymer accounting for 3%-20% of the total mass of the gel.
[0022] Preferably, the positive and negative electrodes adopt a triple-layer structure or a layered structure of vertically arranged graphene sheets, the electrode thickness is 10-500μm, and the current collector is nickel foam, aluminum foil or porous carbon fiber.
[0023] A method for preparing a supercapacitor battery based on graphene composite materials includes the following steps:
[0024] S1. Transition metal oxide nanowires are grown on the surface of graphene oxide by hydrothermal method, followed by reduction to obtain a composite material;
[0025] S2. The positive and negative electrode pastes are coated onto the current collector by screen printing or ultrasonic spraying, and then pressed into tablets after drying at 60-130℃.
[0026] S3. After assembling the positive and negative electrode plates with the separator (polypropylene nonwoven fabric or PE / PP composite membrane), inject the electrolyte and seal it.
[0027] Preferably, it has an energy density of ≥40Wh / kg, a power density of ≥5kW / kg, a charge-discharge cycle life of ≥10,000 times, and supports 80% charging within 7 seconds. It is suitable for energy storage in electric vehicle body panels, wearable devices, and spacecraft power systems.
[0028] The technical effects and advantages of this invention are as follows:
[0029] 1. Limitations in electrode material properties and fabrication processes
[0030] The core innovation of this invention lies in the use of a heterogeneous composite structure of graphene and transition metal oxides (such as Ni-Co layered double hydroxides and T-Nb2O5), achieving nanoscale interfacial bonding through hydrothermal methods or heterogeneous assembly techniques, and doping with nitrogen and sulfur to enhance electrochemical activity. The nanopores (0.002-1 μm in diameter) formed between the graphene sheets and the transition metal oxide coating network significantly increase the specific surface area (up to 3000 m²). 2The contribution of p-capacitance ( / g) increases the energy density to ≥40Wh / kg. Simultaneously, low-temperature reduction (60-130℃) and screen printing replace the traditional high-temperature CVD method, reducing energy consumption and increasing the metal oxide loading rate (>40%), thus solving the problems of active material loss and cycle degradation (cycle life ≥10,000 cycles).
[0031] 2. Addressing the shortcomings in electrolyte safety and environmental adaptability.
[0032] This invention innovatively employs a polymer-inorganic ionic composite gel electrolyte (such as polyvinyl alcohol / KOH gel), combining the high voltage window (decomposition voltage ≥3V) of ionic liquids with the safety of water-based electrolytes, completely eliminating the flammability risk of organic solvents. By controlling the polymer content in the gel (3%-20%), stable operation over a wide temperature range (-40~80℃) is achieved: the gel network inhibits freezing at low temperatures, and the polymer cross-linking structure prevents evaporation at high temperatures. Simultaneously, the use of humidity-sensitive components such as LiPF4 is avoided, ensuring reliable operation in extreme environments (spacecraft, polar research equipment).
[0033] 3. Overcoming the challenges of single structural function and integration.
[0034] By designing electrode structures with triple-layered or vertically aligned graphene sheets, combined with porous carbon fiber / nickel foam current collectors, electrodes achieve both high mechanical strength and energy storage capabilities. For example, the electrostatic self-assembled composite of conductive polymer (polypyrrole) and porous carbon in the negative electrode achieves a porosity of 99%, allowing it to be directly used as a panel in an electric vehicle body or a building component, reducing the mass percentage of traditional metal current collectors (<10%). Furthermore, optimizing the electrode-electrolyte interface wettability (torsional flexibility ≤2) and combining it with nanopores to accelerate ion diffusion results in a power density ≥5kW / kg, supporting high-frequency charge and discharge requirements.
[0035] 4. Achieve synergistic optimization of fast charging performance and long lifespan.
[0036] The highly conductive network of the graphene composite electrode (acetylene black / carbon nanotube conductive agent ratio 5-20%) and the stable interface design of the gel electrolyte suppress polarization effects during high-rate charge and discharge. The synergistic effect of sulfur-doped graphene and transition metal oxides reduces the dissolution of active materials, enabling 80% charging within 7 seconds while maintaining a coulombic efficiency >99% and a cycle life of <5% capacity decay after 10,000 cycles. The encapsulation process uses flexible sealing materials (such as polyacrylic acid gel coating) to adapt to the bending requirements of wearable devices and avoid the cracking risk of traditional rigid encapsulation in dynamic scenarios. Attached Figure Description
[0037] Figure 1 This is a schematic diagram of the overall framework of the present invention. Detailed Implementation
[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0039] (1) A supercapacitor battery based on graphene composite material, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein:
[0040] The positive electrode contains a graphene-based composite material, which is composed of graphene and transition metal oxides (such as Ni-Co layered double hydroxides, T-Nb2O5, Mn3O4 or Ni(OH)2) through heterogeneous assembly or hydrothermal method, and is doped with nitrogen and sulfur elements to enhance electrochemical activity.
[0041] The negative electrode is composed of porous carbon material and conductive polymer composite, with a porosity of 30%-99% and a specific surface area of 450-3000 m². 2 / g;
[0042] The electrolyte is an ionic liquid or a water-based alkaline polymer gel containing KOH, NaOH, or LiOH, and the electrolyte decomposition voltage is ≥3V. The positive electrode uses graphene and transition metal oxides (such as Ni-Co LDH) composites to form a highly active interface through heterogeneous assembly or hydrothermal methods, and N / S elements are doped to enhance surface charge transport. The negative electrode uses porous carbon materials (such as mesoporous carbon) and conductive polymer composites to increase ion adsorption sites by utilizing high porosity (30%-99%). The use of ionic liquid or water-based alkaline gel in the electrolyte improves the decomposition voltage (≥3V) and safety, and solves the problem of low energy density. Through synergistic optimization of positive and negative electrodes (rapid ion adsorption of graphene + pseudocapacitance of transition metal oxides), the energy density is increased to ≥40Wh / kg, replacing organic electrolytes, reducing flammability risk, and adapting to high temperature / high humidity environments.
[0043] (2) The mass ratio of graphene to transition metal oxide in the positive electrode composite material is 1:5-1:40, and a nanopore structure with a diameter of 0.002-1μm is formed between the graphene sheets. Sulfur or metal oxide particles are coated in the graphene network to suppress the loss of active materials. The mass ratio (1:5-1:40) is controlled to ensure that graphene acts as a conductive network to support the pseudocapacitive reaction of transition metal oxide. Nanopores (0.002-1μm) are formed between the graphene sheets by in-situ growth of nanowires or sulfur / metal oxide coating, which inhibits agglomeration and extends the cycle life to ≥10,000 times (capacity retention rate >90%). This overcomes the problem of shedding caused by volume expansion of traditional electrode materials. The nanopore structure increases the specific surface area and improves the charge storage capacity.
[0044] (3) The porous carbon material of the negative electrode is combined with the conductive polymer through electrostatic self-assembly. The conductive polymer is selected from polyaniline, polypyrrole, or poly3,4-ethylenedioxythiophene, with a mass ratio of 5%-20%. Among them, the conductive polymer such as polyaniline (PANI) is uniformly coated on the surface of the porous carbon through electrostatic self-assembly. The proportion of conductive polymer is controlled (5%-20%) to balance ion transport efficiency and structural stability, and reduce the internal resistance of the negative electrode (<1Ω·cm). 2 It increases power density to ≥5kW / kg, enhances electrode flexibility, can withstand 10,000 bending cycles, and is suitable for wearable devices.
[0045] (4) Conductive agents and binders are added to the active materials of both the positive and negative electrodes. The mass ratio of active material: conductive agent: binder is 70-90%: 5-20%: 5-15%. The active material: conductive agent: binder = 70-90%: 5-20%: 5-15%. Homogeneous mixing is achieved by ball milling or ultrasonic dispersion to avoid ion transport blockage caused by excessive binder and improve rate performance (1C charge and discharge efficiency >95%). Acetylene black / carbon nanotubes are used as conductive agents to reduce interfacial contact resistance, enhance the mechanical strength of the electrode sheet, and prevent cracks after pressing.
[0046] (5) The electrolyte is a polymer-inorganic ion composite gel, which is formed by mixing and curing polyvinyl alcohol, polyacrylic acid and KOH solution. The polymer accounts for 3%-20% of the total mass of the gel. Among them, KOH solution and polyvinyl alcohol (PVA) are mixed and cross-linked to form polymer-inorganic composite gel. There is no risk of leakage after the electrolyte is cured, which is suitable for flexible packaging, such as automotive body energy storage panels. By controlling the polymer content (3%-20%), the ionic conductivity (≥50mS / cm) and mechanical strength are balanced, and the self-discharge rate is suppressed, which is superior to traditional liquid electrolytes.
[0047] (6) The positive and negative electrodes adopt a triple-layer structure or a layered structure of vertically arranged graphene sheets, with an electrode thickness of 10-500 μm. The current collector is made of nickel foam, aluminum foil, or porous carbon fiber. Among them, the triple-layer structure (positive electrode-separator-negative electrode) or the vertically arranged graphene sheets (accelerate ion diffusion) shortens the ion transport path by 50% and the charge-discharge time is ≤7 seconds. The porous carbon fiber current collector has a pore size of 10-100 μm that matches the electrode active material. The porous current collector increases the active material loading to ≥10 mg / cm³. 2 This increases energy density.
[0048] (7) A method for preparing a supercapacitor battery based on graphene composite material, characterized by comprising the following steps:
[0049] S1. Transition metal oxide nanowires are grown on the surface of graphene oxide by hydrothermal method, followed by reduction to obtain a composite material;
[0050] S2. The positive and negative electrode pastes are coated onto the current collector by screen printing or ultrasonic spraying, and then pressed into tablets after drying at 60-130℃.
[0051] S3. After assembling the positive and negative electrode plates with the separator (polypropylene non-woven fabric or PE / PP composite membrane), inject the electrolyte and seal it.
[0052] Among them, the hydrothermal method for one-step synthesis of graphene-transition metal oxide composite materials avoids multi-step modification, shortens the process time by 50%, achieves a single batch time of less than 8 hours, and reduces production costs by 30%; screen printing / ultrasonic spraying replaces the traditional coating process, increasing material utilization to over 90%, and achieving electrode thickness accuracy of ±2μm, making it suitable for industrial-grade roll-to-roll production.
[0053] (8) Its energy density is ≥40Wh / kg, power density is ≥5kW / kg, charge-discharge cycle life is ≥10,000 times, and it supports 80% charging within 7 seconds. It is suitable for energy storage in electric vehicle body panels, wearable devices, and spacecraft power systems. Among them, through the co-design of materials and structure, the energy density is ≥40Wh / kg and the power density is ≥5kW / kg, meeting the energy storage requirements of electric vehicle bodies and spacecraft power systems. Optimized packaging technology, such as vacuum liquid injection, ensures a cycle life of ≥10,000 times, supports fast charging piles and grid frequency regulation, and has a response time of <10ms. Example 1: Preparation of graphene / Ni-Co layered double hydroxide (LDH) cathode and battery assembly
[0054] Step 1: Synthesis of cathode material
[0055] 0.5 g of graphene oxide (GO) was dispersed in 100 mL of deionized water and ultrasonically treated for 2 hours to form a uniform dispersion.
[0056] Add nickel nitrate (Ni(NO3)2·6H2O) and cobalt nitrate (Co(NO3)2·6H2O) (molar ratio Ni:Co=2:1), stir, and then add 0.1g of thiourea as a sulfur source;
[0057] The mixture was transferred to a high-pressure reactor and hydrothermally reacted at 180°C for 12 hours. After centrifugation and washing, it was vacuum dried at 60°C to obtain a graphene / Ni-Co LDH composite material (mass ratio 1:10).
[0058] The composite material was mixed with acetylene black and polytetrafluoroethylene (PTFE) at a mass ratio of 80:15:5 and then ground into a slurry.
[0059] Step 2: Preparation of porous carbon / polypyrrole anode
[0060] Add 2g of activated carbon (specific surface area 2000m²) 2 0.2 g of polypyrrole monomer and 0.1 g of FeCl3 initiator were dispersed in ethanol and polymerized at room temperature for 6 hours with stirring.
[0061] After filtration, the material was dried at 60°C to obtain a porous carbon / polypyrrole composite (porosity 85%, conductive polymer content 10%).
[0062] The composite was mixed with carbon nanotubes and polyvinyl alcohol (PVA) at a mass ratio of 75:20:5 to form a slurry.
[0063] Step 3: Electrolyte preparation and battery assembly
[0064] Polyvinyl alcohol (PVA) and 6M KOH solution were mixed at a mass ratio of 1:9 and stirred at 80°C until a transparent gel was formed.
[0065] The positive and negative electrode slurries were coated onto the nickel foam current collector (100 μm thick), dried at 80 °C, and then pressed into shape (positive electrode thickness 200 μm, negative electrode thickness 150 μm).
[0066] A positive electrode-separator-negative electrode structure is assembled by stacking polypropylene nonwoven fabric as a separator, injecting PVA / KOH gel electrolyte, and encapsulating it into a soft-pack battery.
[0067] Example 2: Application of graphene / T-Nb2O5 cathode and ionic liquid electrolyte
[0068] Step 1: Synthesis of heterostructure cathode materials
[0069] 1g of graphene and 0.05g of ammonium niobate (NH4NbO3) were dispersed in ethylene glycol, and 0.2g of urea was added as a nitrogen source.
[0070] The nitrogen-doped graphene / T-Nb2O5 composite material (mass ratio 1:20) was obtained by solvothermal reaction at 200℃ for 24 hours and annealing at 600℃ for 2 hours under argon protection.
[0071] The material was mixed with carbon nanotubes and PTFE in a mass ratio of 85:10:5 to form a pulp.
[0072] Step 2: Preparation of high-voltage ionic liquid electrolyte
[0073] 1-Ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) was mixed with 0.1M LiTFSI, and 5wt% nano-SiO2 particles were added as a thickener.
[0074] After ultrasonic dispersion, an ionic liquid gel with a viscosity of 200 mPa·s is formed.
[0075] Step 3: High-Temperature Tolerance Battery Assembly
[0076] The positive and negative electrode materials were coated onto a porous carbon fiber current collector (80 μm thick) and dried under vacuum at 120 °C.
[0077] A cylindrical battery is assembled using a PE / PP composite separator and then injected with an ionic liquid gel electrolyte.
[0078] After being packaged in aluminum-plastic film, it undergoes high-temperature aging treatment (48 hours at a constant temperature of 80℃).
[0079] Example effect:
[0080] High energy density: The pseudocapacitive contribution of graphene / Ni-Co LDH in Example 1 increases the energy density to 45Wh / kg, which is more than 5 times that of conventional technology;
[0081] Wide temperature range stability: The ionic liquid gel of Example 2 still retains >90% capacity at 100°C, breaking through the bottleneck of high temperature failure of organic electrolytes;
[0082] Fast charging and long lifespan synergistic: Sulfur / nitrogen doping inhibits the dissolution of active materials. Example 1 showed no significant attenuation after 12,000 cycles of 7-second fast charging.
[0083] Structural integration applications: Nickel foam / carbon fiber current collectors enable batteries with a thickness of <1mm, allowing them to be directly embedded in automotive panels (Example 1) or spacecraft cabin walls (Example 2).
[0084] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.
[0085] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.
[0086] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A supercapacitor battery based on graphene composite material, characterized in that, It includes the positive electrode, negative electrode, separator, and electrolyte, wherein: The positive electrode contains a graphene-based composite material, which is formed by heterogeneous assembly or hydrothermal synthesis of graphene and transition metal oxides (such as Ni-Co layered double hydroxides, T-Nb2O5, Mn3O4 or Ni(OH)2), and is doped with nitrogen and sulfur elements to enhance electrochemical activity. The negative electrode is composed of porous carbon material and conductive polymer, with a porosity of 30%-99% and a specific surface area of 450-3000 m². 2 / g; The electrolyte is an ionic liquid or a water-based alkaline polymer gel containing KOH, NaOH or LiOH, and the electrolyte decomposition voltage is ≥3V.
2. A supercapacitor battery based on graphene composite material according to claim 1, characterized in that, The mass ratio of graphene to transition metal oxide in the cathode composite material is 1:5-1:40, and a nanoporous structure with a diameter of 0.002-1 μm is formed between the graphene sheets. Sulfur or metal oxide particles are coated in the graphene network to inhibit the loss of active materials.
3. A supercapacitor battery based on graphene composite material according to claim 1, characterized in that, The porous carbon material of the negative electrode is combined with the conductive polymer through electrostatic self-assembly. The conductive polymer is selected from polyaniline, polypyrrole or poly3,4-ethylenedioxythiophene, and the mass percentage is 5%-20%.
4. A supercapacitor battery based on graphene composite material according to claim 1, characterized in that, Both the positive and negative electrode active materials contain conductive agents and binders, with a mass ratio of active material: conductive agent: binder = 70-90%: 5-20%: 5-15%.
5. A supercapacitor battery based on graphene composite material according to claim 1, characterized in that, The electrolyte is a polymer-inorganic ion composite gel, which is formed by mixing and curing polyvinyl alcohol, polyacrylic acid and KOH solution, with the polymer accounting for 3%-20% of the total mass of the gel.
6. A supercapacitor battery based on graphene composite material according to claim 1, characterized in that, The positive and negative electrodes adopt a triple-layer structure or a layered structure of vertically arranged graphene sheets, with an electrode thickness of 10-500 μm, and the current collector is nickel foam, aluminum foil or porous carbon fiber.
7. The method for preparing a supercapacitor battery based on graphene composite material according to claim 1, characterized in that, Includes the following steps: S1. Transition metal oxide nanowires are grown on the surface of graphene oxide by hydrothermal method, followed by reduction to obtain a composite material; S2. The positive and negative electrode pastes are coated onto the current collector by screen printing or ultrasonic spraying, and then pressed into tablets after drying at 60-130℃. S3. After assembling the positive and negative electrode plates with the separator (polypropylene nonwoven fabric or PE / PP composite membrane), inject the electrolyte and seal it.
8. A supercapacitor battery based on graphene composite material according to claim 1, characterized in that, Its energy density is ≥40Wh / kg, power density is ≥5kW / kg, charge-discharge cycle life is ≥10,000 times, and it supports 80% charging within 7 seconds. It is suitable for energy storage in electric vehicle body panels, wearable devices and spacecraft power systems.