A deionized water-based slurry, its preparation method and application

Abstract

The application provides a deionized water-based slurry and a preparation method and application thereof, and the deionized water-based slurry is prepared by the following method: in a preparation environment at 0-15 DEG C, deionized water is used as a solvent, and a slurry containing active substances, conductive agents and water-based binders is obtained by mixing and stirring; 1.5+ / -0.2wt% propylene glycol is added as an antifreeze agent in the obtained slurry, and 1.0+ / -0.2wt% glycerol is added as a humectant; 3.0+ / -0.5wt% modified polyvinylpyrrolidone is continuously added as a dispersant, ultrasonic treatment is carried out for 25+ / -5 minutes, the particle size of the active substances is controlled to be 17+ / -5 mu m in D50 and 24+ / -5 mu m in D90; through "water-based solvent-composite additive synergistic regulation" and "humidity-temperature precise coupling", the low-temperature preparation bottleneck is broken, and the application is suitable for the industrialized production scene of supercapacitors which has the needs of environmental protection and low-temperature preparation stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical energy storage device preparation, and particularly relates to a deionized water-based slurry, a preparation method and application thereof. BACKGROUND

[0002] In the preparation of a traditional supercapacitor electrode, the water-solvent process cannot be continuously produced under a low-temperature environment (< 15 DEG C) because the slurry viscosity is too large or the soft glue scratch defect occurs. Therefore, the water-solvent process is usually carried out under a normal temperature environment. However, the use of an oily solvent such as N-methyl pyrrolidone can alleviate the low-temperature viscosity problem, but has defects of high VOC emission and high recovery cost.

[0003] Therefore, if the existing water-based slurry (using deionized water as a solvent) is applied under a low-temperature preparation environment (< 15 DEG C), the following technical bottlenecks need to be overcome:

[0004] 1. Solvent icing and viscosity rising: the freezing point of deionized water is 0 DEG C, and the slurry is prone to icing under low temperature, which leads to the loss of flowability of the slurry. Even if the icing is not complete, the viscosity of the slurry will also increase sharply to > 5000 mPa s, which causes defects such as coating breakage and scratches;

[0005] 2. Active material agglomeration: under low temperature, the molecular thermal motion is weakened, and the hydrophilic groups on the surface of the active material in the deionized water system are prone to form hydrogen bonds, which leads to irreversible agglomeration (D50 >= 50 mu m), a loss of specific surface area of more than 30%, and a significant decline in electrochemical performance;

[0006] 3. Poor compatibility between the binder and the substrate: the traditional water-based binder (such as pure CMC) is prone to solidification and brittleness under low temperature, and the adhesion to the aluminum foil substrate is reduced to < 20 gf / mm, which leads to the peeling of the electrode during the cycle process;

[0007] 4. High humidity sensitivity: the deionized water-based slurry is significantly responsive to the environmental humidity, and the humidity fluctuation (RH < 25% or > 60%) under low temperature will lead to the rapid dehydration and caking of the slurry or excessive moisture absorption and dilution, and the rheological property is deteriorated (yield stress > 60 Pa). However, the existing process does not establish a low-temperature-humidity coordinated control strategy for the deionized water solvent, and the preparation stability is poor.

[0008] In addition, the existing technology mainly focuses on the addition of a single antifreeze agent, and does not solve the coordination problem of "antifreeze-dispersion-adhesion-humidity adaptation", which is difficult to meet the electrode preparation requirements under low temperature environment using deionized water as a solvent. Therefore, it is necessary to optimize the existing water-based slurry. SUMMARY

[0009] The technical problem to be solved by the present application is to provide a deionized water-based slurry.

[0010] Another technical problem to be solved by the present application is to provide the preparation method of the deionized water-based slurry.

[0011] Another technical problem to be solved by the present application is to provide the application of the deionized water-based slurry.

[0012] To solve the above technical problems, the technical scheme of the present application is:

[0013] A preparation method of a deionized water-based slurry, the specific steps are as follows:

[0014] (1) In a preparation environment of 0-15℃, a slurry containing active material, conductive agent and water-based binder is obtained by mixing and stirring with deionized water as solvent, wherein the active material is activated carbon with specific surface area ≥ 1500 m 2 / g; the conductive agent is one or a combination of conductive carbon black (Super P, Ketjenblack), carbon nanotube (CNT) and graphene; the water-based binder is a compounded system of sodium carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), and the mass ratio of sodium carboxymethyl cellulose (CMC) to styrene-butadiene rubber (SBR) is 2:1, so as to avoid the solidification and brittleness of the binder at low temperature;

[0015] (2) 1.5±0.2wt% propylene glycol is added to the slurry obtained in step (1) as an antifreeze agent to reduce the freezing point of the slurry to below -25℃ to prevent low-temperature solidification, and 1.0±0.2wt% glycerol is added as a humectant to maintain the water content of the slurry stable (fluctuation rate <8%) through hydrogen bonding;

[0016] (3) 3.0±0.5wt% modified polyvinylpyrrolidone (m-PVP, molecular weight 40,000-60,000 Da, grafted with carboxyl / hydroxyl hydrophilic groups) is added to the slurry obtained in step (2) as a dispersant, and the active material particle size is controlled to D50 of 17±5μm and D90 of 24±5μm after ultrasonic treatment for 25±5 minutes, and the agglomeration is inhibited by the dual action of steric hindrance and hydrophilic adsorption.

[0017] Preferably, the preparation method of the deionized water-based slurry comprises the following steps in step (1):

[0018] 1) The activated carbon and the conductive agent are added to a stirring tank, and the dry powder mixture is obtained by closed stirring;

[0019] 2) Deionized water is added to the dry powder mixture, and the slurry first initial semi-finished product is obtained after stirring;

[0020] 3) Deionized water is added to the dry powder mixture, and the slurry second initial semi-finished product is obtained after stirring and increasing high-speed dispersion;

[0021] 4) After 2-5 times to the slurry secondary initial semi-finished product into deionized water, uniform stirring, get slurry final semi-finished product;

[0022] 5) To the slurry final semi-finished product into water-based binder emulsion, uniform stirring 1min-15min, get active substance, conductive agent and water-based binder slurry as the final slurry product.

[0023] Preferably, the above preparation method of deionized water-based slurry, the relative humidity in steps (1)-(3) is 35%-45%, which can balance the moisture absorption and water loss rate of the deionized water-based slurry, and avoid rheological property mutation.

[0024] Preferably, the above preparation method of deionized water-based slurry, the preparation environment in step (1) is 5-10℃.

[0025] Preferably, the above preparation method of deionized water-based slurry, the modified polyvinylpyrrolidone in step (3) is polyvinylpyrrolidone-carboxyl block copolymer (PVP-COOH).

[0026] The above preparation method of deionized water-based slurry, based on deionized water as the core solvent, through "water-based solvent-composite additive synergistic regulation" and "humidity-temperature precise coupling", the prepared deionized water-based slurry:

[0027] (I) Deionized water-based slurry formula design

[0028] 1. Solvent system optimization: deionized water (degassing treatment) as the only solvent, instead of traditional oil-based solvent, realize VOC zero emission; by adding 1.5±0.2wt% propylene glycol (freezing point-59℃) as an antifreeze, the slurry freezing point is reduced to below-25℃, ensuring no icing or viscosity rising phenomenon under 0-15℃ preparation environment; at the same time, 1.0±0.2wt% glycerol is compounded, using the hydrogen bond interaction between glycerol and water molecules, slowing down the water evaporation rate, maintaining the slurry water content stable (fluctuation rate<8%), avoiding viscosity rising at low temperature.

[0029] 2. Modified dispersant design: using modified PVP (m-PVP) with grafted carboxyl / hydroxyl as dispersant, compared with traditional unmodified dispersant, its hydrophilic group can be adsorbed with the surface hydroxyl group of active substance, weaken the hydrogen bond interaction, combined with the steric hindrance effect of long chain molecules, the active substance particle size is stable controlled at 17±3μm (D50), 24±4μm (D90), specific surface area loss<5%, solving the problem of low temperature agglomeration.

[0030] 3. Water-based binder compounding: CMC and SBR are selected for compounding at a mass ratio of 2:1. CMC provides excellent hydrophilicity and dispersibility, and SBR (glass transition temperature Tg=-50℃) improves the low-temperature flexibility of the binder to avoid low-temperature curing brittleness. At the same time, the aluminum foil substrate is pretreated with a silane coupling agent (KH-550) to enhance the chemical bonding between the binder and the substrate, and the adhesion is increased to ≥80 gf / mm, solving the problem of electrode layer peeling.

[0031] (II) Low-temperature preparation process parameter control

[0032] 1. Temperature window definition: 0-15℃ is defined as the preparation temperature range, preferably 5-10℃; Gradient experiment verification: 0℃, slurry viscosity 1410±50 mPa·s, 5℃, 1340±50 mPa·s, 7℃, 1230±50 mPa·s, 10℃, 1320±50 mPa·s, 15℃, 1460±50 mPa·s; The slurry viscosity in the range of 5-10℃ is stable at 1400-1500 mPa·s, and the coating thickness deviation is <±3μm, which is the optimal preparation temperature window.

[0033] 2. Humidity synergistic control: The relative humidity of the preparation environment is controlled at 20%-60%, preferably 35%-45%; When RH<30%, the water content of the slurry decreases by more than 10% within 1 hour, and the viscosity rises to 1700 mPa·s; When RH>55%, the slurry absorbs moisture, resulting in a decrease in solid content, and the electrode porosity after coating is more than 60%; The interval of 35%-45% can balance the moisture absorption and water loss rate, ensuring that the slurry yield stress is ≤32 Pa and the thixotropic index is ≥1.5.

[0034] 3. Gradient drying process: In view of the problem of easy cracking of deionized water-based slurry at low temperature, a gradient drying of 60℃ (30 minutes)→90℃ (30 minutes) is designed; Slowly remove the surface moisture at low temperature to avoid surface crust; Deeply remove the internal moisture at high temperature to ensure that the electrode moisture content is <1%, compared with the traditional constant temperature drying, the cracking rate is reduced from 15% to <1%.

[0035] A deionized water-based slurry is prepared by the above method.

[0036] The performance verification method of the above deionized water-based slurry is as follows:

[0037] (1) Slurry performance monitoring: Real-time test slurry viscosity (every 30 minutes), particle size distribution (laser particle size analyzer), yield stress and thixotropic index (rheometer) during preparation to ensure that the parameters meet the standards;

[0038] (2) Micro and environmental characterization: After preparation, the electrode morphology is observed by scanning electron microscopy (SEM), the porosity is tested by mercury intrusion method (50±2%), and the binder coverage is analyzed by EDS mapping (≥96%); Gas chromatography-mass spectrometry (GC-MS) is used to test the VOC emission (<1g / m²);

[0039] (3) Electrochemical test: three-electrode system (electrolyte 1M TEABF4 / AN), test specific capacity at 25°C (0.5A / g), internal resistance at -20°C (1kHz) and 5000 cycle stability (1A / g), to ensure the reliability of electrode performance.

[0040] The above deionized water-based slurry is applied in the preparation of supercapacitor electrodes.

[0041] Preferably, the above application, the specific method for preparing supercapacitor electrodes in low temperature environment is as follows:

[0042] (1) The prepared slurry is uniformly coated on the current collector, and the coated semi-finished electrode is obtained after high temperature baking, and the current collector is copper foil or aluminum foil;

[0043] (2) The coated semi-finished electrode is pressed into an electrode semi-finished product, and the pressing method is rolling;

[0044] (3) The pressed semi-finished product is cut to the required width to complete the preparation of the supercapacitor electrode.

[0045] Preferably, the above application, the copper foil or aluminum foil can be surface coated with carbon foil or non-carbon foil or etched foil.

[0046] Preferably, the above application, the rolling method is hot rolling or cold pressing.

[0047] Beneficial effects:

[0048] The preparation method of the deionized water-based slurry solves the problems of poor environmental friendliness of traditional oily solvents and easy agglomeration of water-based slurry in low temperature preparation scene, innovatively uses deionized water as the core solvent, and breaks through the low temperature preparation bottleneck through "water-based solvent-composite additive synergistic regulation" and "humidity-temperature precise coupling", solves the technical pain points of slurry rheological degradation, soft glue scratch defects and other supercapacitor electrode manufacturing in low temperature, and prepares the deionized water-based slurry suitable for the industrial production scene of supercapacitors with demand for environmental friendliness and low temperature preparation stability, which can meet the technical requirements of new energy, special equipment and other fields for high-performance electrodes, and is suitable for batch production.

[0049] The experimental data show that in the preparation environment of relative humidity (RH)=40%, temperature 5-10℃, adding 1.5±0.2wt% propylene glycol (antifreeze), 1.0±0.2wt% glycerol (moisturizing agent) and 3.0±0.5wt% modified polyvinylpyrrolidone (m-PVP, molecular weight 40,000-60,000Da, grafted with hydrophilic groups) to the deionized water-based slurry, after ultrasonic treatment for 25±5 minutes, the viscosity of the prepared electrode slurry is 500-1500mPa·s, the fineness reaches below 20μm, there is no volatile organic compound (VOC) emission, and it is suitable for low-temperature green preparation of supercapacitors in the fields of new energy vehicles, aerospace and the like. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The correlation curve of slurry viscosity and electrode specific capacity under different humidity is shown, the horizontal coordinate is relative humidity (%), the left vertical coordinate is viscosity (mPa·s), and the right vertical coordinate is specific capacity (F / g); it is verified that the viscosity is the lowest and the specific capacity is the highest when RH=40%, verifying the key role of humidity control;

[0051] Figure 2 The electrode cycle stability curve (0-5000 times) is shown, the horizontal coordinate is cycle number, and the vertical coordinate is capacity retention rate (%); the retention rate of the experimental group 2 (RH=40%, 5-10℃) is 95% after 5000 cycles, which is much higher than that of the control group;

[0052] Figure 3 The preparation temperature and slurry viscosity, coating defect rate relationship diagram is shown, the horizontal coordinate is temperature (℃), the left vertical coordinate is viscosity (mPa·s), and the right vertical coordinate is defect rate (%); both of them are at the optimal level in the interval of 5-10℃;

[0053] Figure 4 The SEM image of the electrode of the experimental group 2 (scale 10μm / 50μm) is shown, wherein (a) is the scale 10μm, (b) is the scale 50μm, showing uniform pores, no agglomeration and cracks, and excellent microstructure. DETAILED DESCRIPTION

[0054] The preparation method of the supercapacitor electrode in the low-temperature environment described in the application will be described in detail below in combination with examples and drawings.

[0055] In the following examples, the modified polyvinylpyrrolidone (m-PVP) is a commercially available polyvinylpyrrolidone-carboxyl block copolymer (PVP-COOH). The silane modified aluminum foil is obtained by soaking and drying the aluminum foil in a silane treatment agent. Both are well-known techniques in the art.

[0056] Example 1

[0057] Effect of humidity on the performance of deionized water-based slurry and electrode

[0058] 1. Slurry preparation conditions and preparation method

[0059] Preparation temperature: 10°C (constant);

[0060] Solvent: deionized water (degassed, dissolved oxygen 0.4 mg / L);

[0061] Additives: propylene glycol 1.5 wt%, glycerol 1.0 wt%, m-PVP 3.0 wt% (molecular weight 50,000 Da, carboxyl grafting rate 15%);

[0062] Active material: activated carbon (specific surface area 2200 m² / g);

[0063] Conductive agent: conductive carbon black (Super P)

[0064] Aqueous binder: CMC / SBR (2:1), substrate: silane-modified aluminum foil (20 μm);

[0065] Ultrasonic treatment: 300W digital ultrasonic instrument, 25 minutes;

[0066] Drying process: 60°C→90°C, each for 30 minutes.

[0067] The experimental method is as follows:

[0068] (1) In a 10°C preparation environment, deionized water is used as a solvent to prepare a slurry containing active material, conductive agent and aqueous binder:

[0069] 1-1) Add activated carbon and conductive agent to a stirring tank, stir in a closed state to obtain a dry powder mixture;

[0070] 1-2) Add deionized water to the dry powder mixture, stir to obtain a slurry first initial semi-finished product;

[0071] 1-3) Add deionized water to the dry powder mixture, stir and increase high-speed dispersion to obtain a slurry second initial semi-finished product;

[0072] 1-4) Add deionized water to the slurry second initial semi-finished product for 3 more times, and uniformly stir to obtain a slurry final semi-finished product;

[0073] 1-5) Add an aqueous binder emulsion to the slurry final semi-finished product, uniformly stir for 10 min to obtain a slurry containing active material, conductive agent and aqueous binder as a final slurry finished product;

[0074] (2) Add propylene glycol as an anti-freezing agent to the slurry obtained in step (1) to reduce the freezing point of the slurry to below -25°C to prevent low-temperature solidification, and add glycerol as a humectant to maintain the water content of the slurry stable (fluctuation rate < 8%) through hydrogen bonding;

[0075] (3) Add modified polyvinylpyrrolidone (m-PVP) as a dispersant to the slurry obtained in step (2), and treat it with ultrasound for 25 minutes to control the particle size of the active substance to D50 of 17±5 μm and D90 of 24±5 μm, and use the dual action of steric hindrance and hydrophilic adsorption to inhibit agglomeration.

[0076] 2. Test results, see Table 1, Table 2.

[0077] 2.1 Slurry basic performance:

[0078] Table 1

[0079]

[0080] From Figure 1 and Table 1, it can be seen that the deionized water-based slurry has stable performance, optimal slurry viscosity, yield stress ≤ 32 Pa, and thixotropic index ≥ 1.5 under RH = 35% to 45% relative humidity, which is consistent with the designed process window.

[0081] 2.2 Electrode performance:

[0082] Table 2

[0083]

[0084] From Figure 2 and Table 2, it can be seen that the deionized water-based slurry manufactured under RH = 35% to 45% relative humidity is used for electrode manufacturing, and the manufactured electrode is tested, and the specific capacity (0.5 A / g) and 5000 cycle stability (1 A / g) are optimal. As shown in Figure 4 , under a microscope, the manufactured electrode has uniform pores, no agglomeration and cracks, and excellent microstructure.

[0085] Example 2

[0086] Effect of temperature on the preparation process

[0087] Under RH = 40%, other parameters (deionized water solvent, propylene glycol 1.5 wt%, m-PVP 3.0 wt%) are fixed, and the preparation temperature is adjusted (see Table 3), and the slurry performance is monitored.

[0088] Table 3

[0089]

[0090] From Figure 3As can be seen from Table 3, under the temperature condition of 5-10°C, the deionized water-based slurry has stable performance and optimal coating effect, which is consistent with the designed process window.

[0091] Example 3

[0092] A deionized water-based slurry is prepared by the following method:

[0093] Preparation temperature: 10°C (constant);

[0094] Ambient humidity: RH = 40%;

[0095] Solvent: deionized water;

[0096] Additives: propylene glycol 1.5wt%, glycerol 1.0wt%, m-PVP 3.0wt% (molecular weight 50,000 Da, carboxyl grafting rate 15%);

[0097] Active material: activated carbon (specific surface area 2200 m² / g);

[0098] Conductive agent: conductive carbon black (Super P);

[0099] Water-based binder: CMC / SBR (2:1), substrate: silane-modified aluminum foil (20μm);

[0100] Ultrasonic treatment: 300W digital ultrasonic instrument, 25 minutes;

[0101] Drying process: gradient drying 60°C→90°C, each for 30 minutes.

[0102] The specific steps are as follows:

[0103] (1) In a 10°C preparation environment, deionized water is used as a solvent to prepare a slurry containing active material, conductive agent and water-based binder:

[0104] 1-1) Add activated carbon and conductive agent to a stirring tank, stir in a closed state to obtain a dry powder mixture;

[0105] 1-2) Add deionized water to the dry powder mixture, stir, and obtain a slurry first initial semi-finished product;

[0106] 1-3) Add deionized water to the dry powder mixture, stir and increase high-speed dispersion to obtain a slurry second initial semi-finished product;

[0107] 1-4) Add deionized water to the slurry second initial semi-finished product for 3 more times, and uniformly stir to obtain a slurry final semi-finished product;

[0108] 1-5) adding water-based binder emulsion into the slurry final semi-product, after uniform stirring for 10 min, obtaining the slurry containing active substance, conductive agent and water-based binder as the final slurry product;

[0109] (2) adding propylene glycol into the slurry obtained in step (1), while adding glycerol;

[0110] (3) adding modified polyvinylpyrrolidone (m-PVP) into the slurry obtained in step (2), and treating by ultrasonic for 25 min.

[0111] Example 4

[0112] Using the deionized water-based slurry described in Example 3, supercapacitor electrodes were prepared in a low-temperature environment, and the specific steps were as follows:

[0113] (1) at an ambient temperature of 10℃, the deionized water-based slurry prepared in Example 3 was uniformly coated on an etched aluminum foil, and after high-temperature baking, a semi-finished electrode with completed coating was obtained;

[0114] (2) the semi-finished electrode with completed coating was pressed into a semi-finished electrode by hot rolling;

[0115] (3) the semi-finished product after pressing was cut, and the preparation of the supercapacitor electrode was completed.

[0116] The finished supercapacitor electrode sheet was measured, and the results are shown in Table 4.

[0117] Table 4

[0118]

[0119] As can be seen from Table 4, the deionized water-based slurry has stable performance and excellent coating effect.

[0120] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and all are considered within the scope of the present application.

Claims

1. A method of preparing a deionized water-based slurry, characterized by: The specific steps are as follows: (1) In the preparation environment of 0-15℃, the slurry containing active substance, conductive agent and water-based binder is obtained by mixing and stirring with deionized water as solvent, wherein the active substance is activated carbon with specific surface area ≥ 1500m 2 / g; the conductive agent is one or more combinations of conductive carbon black, carbon nanotube and graphene; the water-based binder is a compound system of sodium carboxymethyl cellulose and butadiene styrene rubber, and the mass ratio of sodium carboxymethyl cellulose to butadiene styrene rubber is 2:1; (2) 1.5±0.2wt% propylene glycol is added to the slurry obtained in step (1) as an antifreezing agent, and 1.0±0.2wt% glycerol is added as a humectant; (3) 3.0±0.5wt% modified polyvinylpyrrolidone with grafted carboxyl / hydroxyl groups is added to the slurry obtained in step (2) as a dispersant, and ultrasonic treatment is performed for 25±5 minutes, so that the particle size of the active substance is controlled to D50 of 17±5 μm and D90 of 24±5 μm.

2. The method of claim 1, wherein: The step (1) comprises the following steps: 1) The active carbon and the conductive agent are added to a stirring tank, and stirring is performed in a closed state to obtain a dry powder mixture; 2) Deionized water is added to the dry powder mixture, and after stirring, a slurry first initial semi-product is obtained; 3) Deionized water is added to the dry powder mixture, and after stirring, high-speed dispersion is increased to obtain a slurry second initial semi-product; 4) Deionized water is further added to the slurry second initial semi-product for 2-5 times, and uniform stirring is performed to obtain a slurry final semi-product; 5) The slurry final semi-product is added with an aqueous binder emulsion, and after uniform stirring for 1-15 minutes, a slurry containing the active substance, the conductive agent and the aqueous binder is obtained as a final slurry product.

3. The method of claim 1, wherein: The relative humidity in the steps (1)-(3) is 35-45%.

4. The method of claim 1, wherein: The preparation environment in the step (1) is 5-10℃.

5. A deionized water-based slurry characterized by: is prepared by the method described in any one of claims 1-4.

6. The method for verifying the properties of the deionized water-based slurry of claim 5, characterized in that: The specific steps are as follows: (1) Slurry performance monitoring: the viscosity, particle size distribution, yield stress and thixotropic index of the slurry are tested in real time during the preparation process to ensure that the parameters meet the standards; (2) Microscopic and environmental characterization: after the preparation is completed, the electrode morphology is observed by scanning electron microscopy, the porosity is tested by mercury injection method, and the binder coverage is analyzed by EDS mapping; gas chromatography-mass spectrometry is used to test the VOC emission; (3) Electrochemical test: three-electrode system, test specific capacity at 25℃, internal resistance at -20℃ and 5000 cycle stability.

7. The application of the deionized water-based slurry of claim 5 in the preparation of a supercapacitor electrode.

8. Use according to claim 7, characterized in that: The specific method for preparing a supercapacitor electrode is as follows: (1) The prepared slurry is uniformly coated on a current collector, and after high-temperature baking, a coated semi-product electrode is obtained, wherein the current collector is a copper foil or an aluminum foil; (2) The coated semi-product electrode is pressed into an electrode semi-product, and the pressing method is rolling; (3) The pressed semi-product is cut into the required width to complete the preparation of the supercapacitor electrode.

9. Use according to claim 8, characterized in that: The surface of the copper foil or the aluminum foil is coated with a carbon foil or is a non-carbon-coated foil or an etched foil.

10. Use according to claim 8, characterized in that: The rolling method in the step (2) is hot rolling or cold rolling.

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