High-performance supercapacitor electrode plate, preparation method and supercapacitor

Abstract

The invention discloses a high-performance supercapacitor electrode plate and a preparation method thereof, and a supercapacitor. The electrode plate comprises an electrode plate current collector; the surface of the electrode plate current collector is coated with an active substance coating; the active material coating comprises active carbon, a binder and a conductive agent; a layer of nano material is deposited on the surface of the active substance coating; the activated carbon is pretreated activated carbon powder; the pretreated activated carbon powder is obtained by acidizing the activated carbon powder before pretreatment. According to the high-performance supercapacitor electrode plate, the preparation method and the supercapacitor, the design is scientific, the electrode plate has the advantages of being high in specific surface area utilization rate, good in conductivity, high in mechanical strength and the like, the capacitance of the supercapacitor can be remarkably improved, the rate performance and cycling stability of the electrode plate are guaranteed, and the service life of the supercapacitor is prolonged. And the overall service life of the super capacitor is prolonged, and great practical significance is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of supercapacitors, and particularly to a high-performance supercapacitor electrode sheet, a preparation method thereof, and a supercapacitor. Background Art

[0002] As a new type of energy storage device, supercapacitors have the advantages of high power density, long cycle life, fast charge and discharge speed, etc., and have broad application prospects in the fields of electric vehicles, smart grids, consumer electronics, etc. Electrode materials are one of the key factors determining the performance of supercapacitors. Activated carbon has become the first choice for supercapacitor electrode materials due to its large specific surface area, good electrical conductivity, high chemical stability, etc.

[0003] However, the traditional preparation method of activated carbon electrode sheets has the following deficiencies:

[0004] 1. Low utilization rate of specific surface area: There are a large number of micropores inside activated carbon, and it is difficult for the electrolyte to infiltrate, resulting in a low utilization rate of the specific surface area and restricting the improvement of the capacitance of supercapacitors;

[0005] 2. Poor electrical conductivity: The contact resistance between activated carbon particles is large, affecting the rate performance and cycle stability of the electrode sheet;

[0006] 3. Low mechanical strength: The electrode sheets prepared by traditional methods have low mechanical strength and are prone to falling off, affecting the overall service life of supercapacitors.

[0007] Therefore, there is an urgent need to develop a technology that can solve the above technical problems. Summary of the Invention

[0008] The purpose of the present invention is to provide a high-performance supercapacitor electrode sheet, a preparation method thereof, and a supercapacitor for the technical defects existing in the prior art.

[0009] To this end, the present invention provides a high-performance supercapacitor electrode sheet, including an electrode sheet current collector;

[0010] The surface of the electrode sheet current collector is coated with an active material coating;

[0011] The active material coating includes: activated carbon, a binder, and a conductive agent;

[0012] A layer of nanomaterial is deposited on the surface of the active material coating;

[0013] The activated carbon is pretreated activated carbon powder;

[0014] The pretreated activated carbon powder is the activated carbon powder obtained after acid treatment of the activated carbon powder before pretreatment;

[0015] The mass ratio among the activated carbon powder, conductive agent, and binder before pretreatment is (20 - 60):(1 - 3):(1 - 5).

[0016] In addition, the present invention provides a supercapacitor, which includes the high-performance supercapacitor electrode sheet as described above.

[0017] Furthermore, the present invention provides a method for preparing the high-performance supercapacitor electrode sheet as described above, which includes the following steps:

[0018] Step S1, pretreatment of activated carbon;

[0019] Specifically: subject the activated carbon powder to acid treatment to obtain the pretreated activated carbon powder;

[0020] Step S2, addition of conductive agent and binder;

[0021] Specifically: mix the pretreated activated carbon powder with the conductive agent and binder, add a solvent and stir evenly to prepare an electrode sheet slurry;

[0022] Step S3, preparation of electrode sheet blank;

[0023] Specifically: evenly coat the electrode sheet slurry prepared in Step S2 on the electrode sheet current collector, and then through the processes of drying and pressing, prepare an electrode sheet blank;

[0024] Step S4, activation treatment of electrode sheet blank;

[0025] Specifically: subject the electrode sheet blank to high-temperature heat treatment under the protection of an inert gas;

[0026] Step S5, modify the surface of the electrode sheet blank to obtain a finished electrode sheet;

[0027] Specifically: for the electrode sheet blank after activation treatment, deposit a layer of nanomaterial on the surface of the electrode sheet blank by chemical vapor deposition or electrochemical deposition to obtain a finished electrode sheet.

[0028] As can be seen from the technical solutions provided by the present invention above, compared with the prior art, the present invention provides a high-performance supercapacitor electrode sheet, a preparation method thereof, and a supercapacitor. Its design is scientific. The electrode sheet of the present invention has the advantages of high specific surface area utilization rate, good conductivity, high mechanical strength, etc., which is conducive to significantly improving the capacitance of the supercapacitor, ensuring the rate performance and cycle stability of the electrode sheet, extending the overall service life of the supercapacitor, and has great practical significance. Description of the Drawings

[0029] Figure 1 is a flowchart of a conventional electrode sheet manufacturing process in the prior art;

[0030] Figure 2 It is the working flowchart of a preparation method for a high-performance supercapacitor electrode sheet provided by the present invention;

[0031] Figure 3 It is a schematic diagram for comparing the specific surface area test of the electrode sheets prepared in Example 1 and Example 2 of the method of the present invention with the electrode sheet prepared in Comparative Example 1 using the traditional method;

[0032] Figure 4 It is a schematic diagram for comparing the electrochemical performance test of the electrode sheets prepared in Example 1 and Example 2 of the method of the invention with the electrode sheet prepared in Comparative Example 1 using the traditional method;

[0033] Figure 5 It is a schematic diagram for comparing the cycle stability test of the electrode sheets prepared in Example 1 and Example 2 of the method of the invention with the electrode sheet prepared in Comparative Example 1 using the traditional method. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0036] In the description of this patent, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "connection", "setting" should be understood in a broad sense. For example, it can be fixedly connected and set, or detachably connected and set, or integrally connected and set. For those of ordinary skill in the art, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0037] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0038] A high-performance supercapacitor electrode sheet provided by the present invention includes: an electrode sheet current collector;

[0039] The surface of the electrode sheet current collector (such as the upper and lower surfaces) is coated with an active material coating;

[0040] The active material coating contains: activated carbon, binder, and conductive agent;

[0041] A layer of nanomaterial is deposited on the surface of the active material coating.

[0042] In the present invention, specifically, the electrode sheet current collector is aluminum foil or copper foil.

[0043] In the present invention, specifically, the activated carbon is specifically pretreated activated carbon powder (as the electrode active material);

[0044] The pretreated activated carbon powder is obtained by acidifying the activated carbon powder before pretreatment (i.e., the non-acidified activated carbon powder).

[0045] Specifically, the mass ratio among the activated carbon powder before pretreatment, the conductive agent, and the binder is (20 - 60):(1 - 3):(1 - 5);

[0046] Specifically, the mass ratio among the activated carbon powder before pretreatment, the conductive agent, and the binder is preferably 40:2:1.

[0047] Specifically, further, acidifying the activated carbon powder before pretreatment (i.e., the non-acidified activated carbon powder) to obtain the pretreated activated carbon powder specifically includes the following steps:

[0048] The first step, acid solution preparation: Select nitric acid, sulfuric acid, or hydrochloric acid to prepare an acid solution with a concentration of 1 - 6 mol / L;

[0049] The second step, acidification treatment: Add the activated carbon powder to the acid solution, and the mass ratio of the activated carbon powder to the acid solution is 1:10 - 1:20, then stir at 50 - 100 °C for 2 - 12 hours to make the surface of the activated carbon powder fully react with the acid, remove the surface impurities of the activated carbon powder, and form a mixed solution;

[0050] The third step, washing and drying: Wash the mixed solution in the second step repeatedly with deionized water to make it change from acidic to neutral, then dry it at 80 - 120 °C for standby to obtain the dried activated carbon powder, that is, obtain the pretreated activated carbon powder.

[0051] It should be noted that for the high-performance supercapacitor electrode sheet of the present invention, the activated carbon powder contained in the active material coating thereon is the activated carbon powder after acid treatment. Acid treatment of the activated carbon powder can effectively remove surface impurities, improve its surface activity, increase its specific surface area and porosity, thereby improving the specific capacitance of the electrode sheet.

[0052] In the present invention, specifically, the nanomaterials deposited on the surface of the active material coating are nanomaterials including silicon dioxide, titanium dioxide or carbon nanotubes. For example, it may specifically include: silicon dioxide nanoparticles, titanium dioxide nanoparticles, carbon nanotube nanoparticles, metal oxide (such as manganese dioxide) nanoparticles or conductive polymer (such as polyaniline) nanofibers.

[0053] Based on the high-performance supercapacitor electrode sheet provided by the above-mentioned present invention, the present invention also provides a supercapacitor, which includes a high-performance supercapacitor electrode sheet as described above.

[0054] See Figures 2 to 5 , in order to prepare the high-performance supercapacitor electrode sheet provided by the above-mentioned present invention, the present invention also provides a preparation method of the high-performance supercapacitor electrode sheet, including the following steps:

[0055] Step S1, activated carbon pretreatment;

[0056] Specifically: Acidify the activated carbon powder to obtain the pretreated activated carbon powder;

[0057] Step S2, addition of conductive agent and binder;

[0058] Specifically: Mix the pretreated activated carbon powder with the conductive agent and the binder, add a solvent and stir evenly to prepare an electrode sheet slurry;

[0059] Step S3, preparation of electrode sheet blank;

[0060] Specifically: Uniformly coat the electrode sheet slurry prepared in Step S2 on the electrode sheet current collector, and then through the drying and pressing processes, prepare an electrode sheet blank;

[0061] Step S4, activation treatment of the electrode sheet blank;

[0062] Specifically: Heat-treat the electrode sheet blank at a high temperature (such as 300 - 600 °C) under the protection of an inert gas;

[0063] Step S5, modify the surface of the electrode sheet blank to obtain a finished electrode sheet;

[0064] Specifically: for the activated electrode blank, a layer of nanomaterials is modified (i.e., deposited) on the surface of the electrode blank by chemical vapor deposition or electrochemical deposition to obtain the finished electrode sheet.

[0065] In the present invention, the high-performance supercapacitor electrode sheet includes a positive electrode sheet and / or a negative electrode sheet, which can be a positive electrode sheet or a negative electrode sheet.

[0066] For the present invention, in step S1, it should be noted that acidifying the activated carbon powder can effectively remove the surface impurities, improve its surface activity, increase its specific surface area and porosity, thereby improving the specific capacitance of the electrode sheet.

[0067] For the present invention, specifically, in step S1, the activated carbon powder (i.e., the activated carbon powder before treatment, that is, the non-acidified activated carbon powder) is acidified to obtain the pretreated activated carbon powder, which specifically includes the following steps:

[0068] Step S101, preparation of acid solution: Select nitric acid, sulfuric acid or hydrochloric acid to prepare an acid solution with a concentration of 1-6 mol / L;

[0069] Step S102, acidification treatment: Add the activated carbon powder to the acid solution, and the mass ratio of the activated carbon powder to the acid solution is 1:10-1:20. Then stir at 50-100 °C for 2-12 hours to make the surface of the activated carbon powder fully react with the acid, remove the surface impurities of the activated carbon powder, and form a mixed solution;

[0070] Step S103, washing and drying: Wash the mixed solution in step S102 repeatedly with deionized water to make it change from acidic to neutral, and then dry it at 80-120 °C for standby to obtain the dried activated carbon powder, that is, the pretreated activated carbon powder.

[0071] For the present invention, specifically, in step S2, the conductive agent is carbon nanotubes or graphene;

[0072] The binder is polyvinylidene fluoride or sodium carboxymethyl cellulose;

[0073] The solvent is N-methylpyrrolidone or deionized water.

[0074] For the present invention, specifically, in step S2, the pretreated activated carbon powder is the activated carbon powder obtained after acidifying the activated carbon powder before pretreatment.

[0075] For the present invention, in step S2, the mass ratio among the activated carbon powder before pretreatment, the conductive agent and the binder is (20-60):(1-3):(1-5);

[0076] In specific implementation, the mass ratio among the activated carbon powder, conductive agent and binder before pretreatment is preferably 40:2:1.

[0077] In step S2, in specific implementation, the solid content of the electrode sheet slurry is 20-50%.

[0078] For the present invention, in specific implementation, in step S3, the current collector of the electrode sheet is aluminum foil or copper foil.

[0079] For the present invention, in step S4, it should be noted that the activation treatment of the green electrode sheet has the following specific functions: heat-treating the green electrode sheet under the protection of an inert gas at a high temperature (such as 300-600 °C) to remove residual solvents and improve the conductivity and mechanical strength of the electrode sheet.

[0080] For the present invention, in specific implementation, in step S4, heat-treating the green electrode sheet under the protection of an inert gas at a high temperature (such as 300-600 °C) specifically includes the following steps:

[0081] Step S401, equipment preparation: Place the prepared electrode sheet into a tube furnace to ensure that the electrode sheet is evenly distributed in the furnace chamber of the tube furnace;

[0082] Step S402, inert gas protection: Introduce an inert gas into the furnace chamber of the tube furnace to remove the air in the furnace chamber of the tube furnace and prevent the electrode sheet from oxidizing at high temperature;

[0083] In step S402, in specific implementation, the inert gas is preferably argon or nitrogen.

[0084] Step S403, perform a heating operation: At a heating rate of 5-10 °C / min, raise the temperature in the furnace chamber of the tube furnace to 300-600 °C and keep it warm for 1-5 hours;

[0085] Step S404, perform a cooling operation: Naturally cool the temperature in the furnace chamber of the tube furnace to room temperature, and then take out the green electrode sheet from the furnace chamber of the tube furnace.

[0086] In step S402, in specific implementation, the room temperature specifically corresponds to a temperature range of 15-25 °C.

[0087] For the present invention, in step S5, it should be noted that modifying the surface of the green electrode sheet specifically means: Using methods such as chemical vapor deposition and electrochemical deposition to modify a layer of nanomaterials (such as metal oxides or conductive polymers, etc.) on the surface of the green electrode sheet to further improve the specific surface area and electrochemical performance of the electrode sheet.

[0088] For the present invention, in terms of specific implementation, in step S5, for the activated electrode sheet blank, a layer of nanomaterials is modified on the surface of the electrode sheet blank by chemical vapor deposition to obtain a finished electrode sheet, which specifically includes the following steps:

[0089] Step S511, equipment preparation: Place the electrode sheet blank into the chemical vapor deposition equipment to ensure the cleanliness of the electrode sheet surface;

[0090] Step S512, reaction gas: Select a metal organic compound (such as tetraethoxysilane, tetrabutyl titanate, etc.) or a carbon source gas (such as methane, ethylene, etc.) as the reaction gas;

[0091] Step S513, perform reaction operation: Set the working parameters of the chemical vapor deposition equipment so that the electrode sheet blank and the reaction gas carry out a chemical reaction at a temperature of 300 - 800 °C and a pressure of 1 - 10 kPa, and the reaction time is 1 - 5 hours;

[0092] Step S514, form a deposition layer: Through chemical reaction, a corresponding layer of nanomaterials (such as silicon dioxide, titanium dioxide, or carbon nanotubes, etc.) is deposited on the surface of the electrode sheet blank to obtain a finished electrode sheet.

[0093] In step S512, the reaction gas is tetraethoxysilane, tetrabutyl titanate, methane, or ethylene.

[0094] Specifically in the present invention, when the reaction gas in step S512 selects tetraethoxysilane, a corresponding layer of nanomaterials deposited on the surface of the electrode sheet blank through step S514 is silicon dioxide nanoparticles.

[0095] Specifically in the present invention, when the reaction gas in step S512 selects tetrabutyl titanate, a corresponding layer of nanomaterials deposited on the surface of the electrode sheet blank through step S514 is titanium dioxide nanoparticles.

[0096] Specifically in the present invention, when the reaction gas in step S512 selects methane or ethylene, a corresponding layer of nanomaterials deposited on the surface of the electrode sheet blank through step S514 is carbon nanotube nanoparticles.

[0097] It should be noted that the chemical vapor deposition equipment is a mature and well-known device in the prior art, and will not be elaborated here.

[0098] For the present invention, in terms of specific implementation, in step S5, for the activated electrode sheet blank, a layer of nanomaterials is modified on the surface of the electrode sheet blank by electrochemical deposition to obtain a finished electrode sheet, which is based on an electrochemical workstation for electro-deposition, and specifically includes the following steps:

[0099] Step S521, electrolyte preparation: Select an electrolyte containing ions of the material to be deposited (such as metal ions, polymer monomers, etc.);

[0100] In step S521, specifically, the ions of the material to be deposited include metal ions or polymer monomers;

[0101] Among them, metal ions include at least one of copper ions (Cu 2+ ), manganese ions (Mn 2+ ), and nickel ions (Ni 2+ ), and are not limited to these metal ions;

[0102] Polymer monomers include polypyrrole (PPy) and / or polyaniline (PAn), and are not limited to these two polymer monomers.

[0103] Furthermore, in the electrolyte, when the ions of the material to be deposited include metal ions, the concentration of the metal ions is between 0.01 M and 1 M (mol / L);

[0104] Furthermore, in the electrolyte, when the ions of the material to be deposited include polymer monomers, the concentration of the polymer monomers is between 0.001 M and 0.1 M (mol / L).

[0105] In step S521, specifically, for the electrolyte, the solvent it has can be selected from water or organic solvents. Organic solvents include, for example, at least one of ethanol, acetone, and N,N-dimethylformamide (DMF), and are not limited to these organic solvents.

[0106] In step S521, for the electrolyte, the electrolyte it has can be selected from sodium sulfate (Na2SO4), sodium chloride (NaCl), potassium sulfate (K2SO4), potassium chloride (KCl), etc., that is, it can include at least one of sodium sulfate (Na2SO4), sodium chloride (NaCl), potassium sulfate (K2SO4), and potassium chloride (KCl). For example, regarding the electrochemical deposition of manganese ions, the electrolyte composition may be MnSO4 (concentration 0.1 M), Na2SO4 0.5 (concentration M), and the solvent is water.

[0107] Step S522, electrode setting: Use the blank electrode sheet as the working electrode, a platinum sheet as the counter electrode, and the reference electrode can be selected from a saturated calomel electrode, a silver electrode, or a silver chloride electrode;

[0108] Step S523, deposition conditions: Immerse the working electrode, counter electrode, and reference electrode into the electrolyte, and then use an electrochemical workstation to perform electro-deposition operations on the working electrode. Specifically, it is required to perform electrochemical deposition at a voltage of 1 - 5 V and a current density of 1 - 10 mA / cm 2 for a deposition time of 10 - 60 minutes;

[0109] Step S524, forming a deposition layer: Through the electro-deposition operation in step S523, a layer of nanomaterials (such as metal oxides, conductive polymers, etc.) is deposited on the surface of the blank electrode sheet serving as the working electrode.

[0110] Specifically, in the present invention, when the ions of the material to be deposited in step S521 are metal ions (for example, Mn 2+ ), a corresponding layer of nanomaterials deposited on the surface of the blank electrode sheet through step S524 is metal oxide (such as manganese dioxide) nanoparticles.

[0111] Specifically, in the present invention, when the ions of the material to be deposited in step S521 are polymer monomers (for example, aniline monomer), a corresponding layer of nanomaterials deposited on the surface of the blank electrode sheet through step S524 is conductive polymer (such as polyaniline) nanofibers.

[0112] It should be noted that the electrochemical workstation is a mature and well-known device in the prior art, and will not be elaborated here.

[0113] In order to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described below through specific embodiments.

[0114] Example 1

[0115] First step, add 10 g of activated carbon powder into 100 mL of 6 mol / L nitric acid solution, stir at 80 °C for 6 hours, then wash with deionized water until neutral, and dry for later use;

[0116] Second step, mix the pretreated activated carbon powder (as the electrode active material) with 0.5 g of carbon nanotubes (as the conductive agent) and 0.5 g of polyvinylidene fluoride (as the binder), add 20 mL of N-methylpyrrolidone (as the solvent), stir evenly to make a slurry;

[0117] Third step, evenly coat the slurry on the aluminum foil serving as the electrode sheet current collector, dry at 80 °C, and then press into a sheet to make a blank electrode sheet;

[0118] Fourth step, heat-treat the blank electrode sheet at 500 °C for 2 hours under argon protection;

[0119] Fifth step, use chemical vapor deposition to modify a layer of manganese dioxide nanoparticles on the surface of the blank electrode sheet to obtain a finished electrode sheet.

[0120] Example 2

[0121] First step: Add 10 g of activated carbon powder into 100 mL of 6 mol / L nitric acid solution, stir at 80 °C for 6 hours, then wash with deionized water until neutral, and dry for standby.

[0122] Second step: Mix the pretreated activated carbon powder (as the electrode active material) with 0.5 g of graphene (as the conductive agent) and 0.5 g of sodium carboxymethyl cellulose (as the binder), add 20 mL of deionized water (as the solvent), stir evenly to make a slurry.

[0123] Third step: Coat the slurry evenly on the copper foil serving as the electrode sheet current collector, dry at 80 °C, and then press into a sheet to make a blank electrode sheet.

[0124] Fourth step: Heat-treat the blank electrode sheet at 500 °C for 2 hours under argon protection.

[0125] Fifth step: Modify a layer of polyaniline nanofibers on the surface of the blank electrode sheet by electrochemical deposition method to obtain the finished electrode sheet.

[0126] Comparative Example 1

[0127] Prepare a supercapacitor electrode sheet by a traditional method. The specific steps are as follows: Mix the activated carbon powder with the conductive agent and the binder, add the solvent and stir evenly to make a slurry, then coat the slurry on the electrode sheet current collector, dry, and press to obtain the finished electrode sheet.

[0128] It should be noted that when preparing the supercapacitor electrode sheet by the traditional method, the conductive agent can be carbon nanotubes, carbon black or acetylene black; the binder can be acrylic PPA, sodium carboxymethyl cellulose CMC or styrene-butadiene rubber SBR; the solvent can be water, NMP or DMC.

[0129] In Comparative Example 1, the conductive agent is carbon nanotubes, the binder is acrylic PPA, and the solvent is deionized water.

[0130] In Comparative Example 1, regarding the activated carbon powder, the conductive agent and the binder, specifically, it can be: 10 g of activated carbon powder, 0.5 g of carbon nanotubes and 0.5 g of acrylic PPA, and the volume of deionized water is 20 ml.

[0131] In Comparative Example 1, the electrode sheet current collector is aluminum foil.

[0132] Regarding Comparative Example 1, as Figure 1As shown, the manufacturing process flow of the original and traditional supercapacitor electrode sheets includes processes such as adding activated carbon, conductive agent, binder, and preparing electrode sheets. Its process is relatively simple and rough. Although it may have advantages in production efficiency, there are obvious deficiencies in product quality and performance. Therefore, from the perspective of pursuing excellent performance and long-term stability, the traditional manufacturing process is not perfect and refined enough.

[0133] For the present invention, as Figure 2 shown, the manufacturing process flow of the supercapacitor electrode sheets of the present invention includes multiple steps such as activated carbon pretreatment, adding conductive agent, binder, preparing electrode sheets, activating electrode sheets, and surface modification of electrode sheets. Its process is rigorous and well-considered, fully reflecting the ultimate pursuit of product quality and performance.

[0134] The following combines specific test operations to illustrate the technical advantages of the supercapacitor electrode sheets prepared by the present invention.

[0135] 1. As Figure 3 shown, the specific description of the specific surface area test of the supercapacitor electrode sheets manufactured by the present invention and the electrodes manufactured by the original and traditional processes is as follows:

[0136] The BET method was used to test the specific surface area of the electrode sheets prepared in Example 1, Example 2, and Comparative Example 1. From Figure 3 it can be seen that the results show that the specific surface areas of the electrode sheets in Example 1 and Example 2 of the present invention are 2500 m 2 / g and 2300 m 2 / g respectively, which are significantly higher than 1800 m 2 / g of the electrode sheet in Comparative Example 1. It shows that: the specific surface area of the electrode sheets made by the supercapacitor manufacturing process of the present invention is higher than that of the electrode sheets made by the original and traditional processes.

[0137] 2. As Figure 4 shown, the specific description of the electrochemical performance test of the supercapacitor electrodes manufactured by the present invention and the traditional process is as follows:

[0138] The three-electrode system was used to test the electrochemical performance of the electrodes prepared in Example 1, Example 2, and Comparative Example 1. From Figure 4 it can be seen that the results show that at a current density of 1 A / g, the specific capacitances of the electrode sheets in Example 1 and Example 2 of the present invention are 350 F / g and 330 F / g respectively, which are significantly higher than the specific capacitance of 250 F / g of the electrode sheet in Comparative Example 1.

[0139] At a current density of 10 A / g, the specific capacitance retention rates of the electrode sheets of Example 1 and Example 2 of the present invention are 85% and 80% respectively, which are significantly higher than the specific capacitance retention rate of 60% of the electrode sheet of Comparative Example 1. It shows that the electrochemical performance of the electrode sheets made by the supercapacitor manufacturing process of the present invention is higher than that of the electrode sheets made by the original and traditional processes.

[0140] III. As Figure 5 shown, the cycle stability test of the supercapacitor electrode manufacturing process of the present invention and the electrodes manufactured by the original and traditional processes is specifically described as follows:

[0141] At a current density of 1 A / g, charge-discharge cycle tests were carried out on the electrode sheets prepared in Example 1, Example 2 and Comparative Example 1 for 5000 times. From Figure 5 it can be seen that the results show that the capacitance retention rates of the electrode sheets of Example 1 and Example 2 of the present invention are 95.2% and 90.1% respectively, which are significantly higher than the capacitance retention rate of 75.2% of the electrode sheet of Comparative Example 1. It shows that the cycle stability of the electrode sheets made by the supercapacitor manufacturing process of the present invention is higher than that of the electrode sheets made by the original and traditional processes.

[0142] From the technical solutions provided by the present invention above, compared with the prior art, the present invention provides a high-performance supercapacitor electrode sheet and a preparation method thereof, with scientific design. The electrode sheet of the present invention has the advantages of high specific surface area utilization rate, good conductivity, high mechanical strength, etc., which is beneficial to significantly improving the capacitance of the supercapacitor, ensuring the rate performance and cycle stability of the electrode sheet, and prolonging the overall service life of the supercapacitor, having great practical significance.

[0143] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can still be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A high-performance supercapacitor electrode sheet, characterized in that: including an electrode sheet current collector; The surface of the electrode sheet current collector is coated with an active material coating; An active material coating, comprising: activated carbon, a binder and a conductive agent; On the surface of the active material coating, a layer of nanomaterial is deposited; Activated carbon is pre-treated activated carbon powder; The pretreated activated carbon powder is an activated carbon powder obtained by subjecting the pretreated activated carbon powder to an acidification treatment; The mass ratio of activated carbon powder, conductive agent and binder before pretreatment is (20-60):(1-3):(1-5).

2. The high performance supercapacitor electrode sheet according to claim 1, characterized in that: The electrode sheet current collector is aluminum foil or copper foil; and / or, The mass ratio of activated carbon powder, conductive agent and binder before pretreatment is 40:2:

1.

3. The high performance supercapacitor electrode sheet according to claim 1, characterized in that: The activated carbon powder before pretreatment is subjected to acidification treatment to obtain the activated carbon powder after pretreatment, which specifically comprises the following steps: The first step is to prepare an acid solution: select nitric acid, sulfuric acid or hydrochloric acid to prepare an acid solution with a concentration of 1 to 6 mol / L; The second step is acidification treatment: adding activated carbon powder to the acid solution, the mass ratio of activated carbon powder to acid solution is 1:10-1:20, and then stirring at 50-100°C for 2-12 hours to allow the surface of the activated carbon powder to fully react with the acid, remove surface impurities of the activated carbon powder, and form a mixed solution; The third step is washing and drying: the mixed solution in the second step is repeatedly washed with deionized water to change it from acidic to neutral, and then dried at 80-120°C for use to obtain the dried activated carbon powder, that is, the pretreated activated carbon powder.

4. The high performance supercapacitor electrode sheet according to claim 1, characterized in that: The nanomaterial deposited on the surface of the active substance coating is a nanomaterial including silicon dioxide, titanium dioxide or carbon nanotubes.

5. A supercapacitor, characterized in that: The invention comprises a high performance supercapacitor electrode sheet as claimed in any one of claims 1 to 3.

6. A method for preparing a high-performance supercapacitor electrode sheet according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1, activated carbon pretreatment; Specifically, the activated carbon powder is subjected to an acidification treatment to obtain a pretreated activated carbon powder; Step S2, adding conductive agent and binder; Specifically, the pretreated activated carbon powder is mixed with a conductive agent and a binder, and a solvent is added and stirred evenly to prepare an electrode sheet slurry; Step S3, preparing electrode blanks; Specifically, the electrode sheet slurry prepared in step S2 is evenly coated on the electrode sheet current collector, and then dried and pressed to obtain an electrode sheet blank; Step S4, activation treatment of the electrode blank; Specifically, the electrode sheet blank is subjected to high temperature heat treatment under the protection of inert gas; Step S5, modifying the surface of the electrode sheet blank to obtain a finished electrode sheet; Specifically, for the electrode sheet blank that has been activated, a layer of nanomaterial is deposited on the surface of the electrode sheet blank by chemical vapor deposition or electrochemical deposition to obtain a finished electrode sheet.

7. The preparation method according to claim 6, characterized in that: In step S1, the activated carbon powder is subjected to an acidification treatment to obtain pretreated activated carbon powder, which specifically includes the following steps: Step S101, acid solution preparation: select nitric acid, sulfuric acid or hydrochloric acid to prepare an acid solution with a concentration of 1 to 6 mol / L; Step S102, acidification treatment: adding activated carbon powder to an acid solution, with a mass ratio of activated carbon powder to acid solution of 1:10 to 1:20, and then stirring at 50 to 100° C. for 2 to 12 hours to allow the surface of the activated carbon powder to fully react with the acid, remove surface impurities of the activated carbon powder, and form a mixed solution; Step S103, washing and drying: repeatedly washing the mixed solution in step S102 with deionized water to change it from acidic to neutral, and then drying it at 80-120° C. for standby use to obtain a dried activated carbon powder, that is, to obtain a pretreated activated carbon powder; and / or, In step S2, the conductive agent is carbon nanotubes or graphene; The binder is polyvinylidene fluoride or sodium carboxymethyl cellulose; The solvent is N-methylpyrrolidone or deionized water; and / or, In step S2, the mass ratio of the activated carbon powder, the conductive agent and the binder before pretreatment is (20-60): (1-3): (1-5); and / or, In step S2, the solid content of the electrode sheet slurry is 20-50%; and / or, In step S4, the electrode sheet blank is subjected to high temperature heat treatment under the protection of an inert gas, which specifically includes the following steps: Step S401, equipment preparation: placing the prepared electrode sheets into a tube furnace, ensuring that the electrode sheets are evenly distributed in the furnace of the tube furnace; Step S402, inert gas protection: inert gas is introduced into the furnace of the tube furnace to remove the air in the furnace of the tube furnace to prevent the electrode sheet from being oxidized at high temperature; Step S403, performing a heating operation: heating the temperature in the furnace of the tube furnace to 300-600° C. at a heating rate of 5-10° C. / min, and keeping the temperature for 1-5 hours; Step S404, performing a cooling operation: naturally cooling the temperature in the furnace of the tube furnace to room temperature, and then taking out the electrode sheet blank from the furnace of the tube furnace.

8. The preparation method according to claim 6, characterized in that: In step S5, for the electrode sheet blank that has been activated, a layer of nanomaterial is modified on the surface of the electrode sheet blank by chemical vapor deposition to obtain a finished electrode sheet, which specifically includes the following steps: Step S511, equipment preparation: placing the electrode sheet blank into the chemical vapor deposition equipment to ensure that the surface of the electrode sheet is clean; Step S512, reaction gas: selecting a metal organic compound or a carbon source gas as the reaction gas; Step S513, executing a reaction operation: setting the working parameters of the chemical vapor deposition equipment so that the electrode blank and the reaction gas undergo a chemical reaction at a temperature of 300 to 800° C. and a pressure of 1 to 10 kPa, and the reaction time is 1 to 5 hours; Step S514, forming a deposition layer: through chemical reaction, a layer of corresponding nanomaterial is deposited on the surface of the electrode sheet blank to obtain a finished electrode sheet.

9. The preparation method according to claim 6, characterized in that: In step S5, for the electrode sheet blank that has been activated, a layer of nanomaterial is modified on the surface of the electrode sheet blank by electrochemical deposition to obtain a finished electrode sheet. The electrodeposition is performed based on an electrochemical workstation, and specifically includes the following steps: Step S521, electrolyte preparation: selecting an electrolyte containing ions of the material to be deposited; Step S522, electrode setting: the electrode blank is used as the working electrode, the platinum sheet is used as the counter electrode, and the reference electrode is selected from a saturated calomel electrode, a silver electrode or a silver chloride electrode; Step S523, deposition conditions: put the working electrode, counter electrode and reference electrode into the electrolyte, and then use the electrochemical workstation to perform electrodeposition operation on the working electrode, specifically requiring a voltage of 1 to 5 V and a current of 1 to 10 mA / cm 2 Electrochemical deposition is carried out at a current density of , and the deposition time is 10-60 minutes; Step S524, forming a deposition layer: through the electrodeposition operation of step S523, a layer of nanomaterial is deposited on the surface of the electrode sheet blank serving as the working electrode.

10. The preparation method according to claim 9, characterized in that: In step S521, the material ions to be deposited include metal ions or polymer monomers; Among them, metal ions, including copper ions Cu 2+ 、Manganese ion Mn 2+ and nickel ions Ni 2+ At least one of; Polymer monomers, including polypyrrole PPy and / or polyaniline Pan; In the electrolyte, when the ions of the material to be deposited include metal ions, the concentration of the metal ions is between 0.01M and 1M; In the electrolyte, when the ions of the material to be deposited include polymer monomers, the concentration of the polymer monomers is between 0.001M and 0.1M; and / or, In step S521, the electrolyte has a solvent of water or an organic solvent, and the organic solvent includes at least one of ethanol, acetone and N,N-dimethylformamide; In step S521, the electrolyte solution has an electrolyte including at least one of sodium sulfate Na2SO4, sodium chloride NaCl, potassium sulfate K2SO4 and potassium chloride KCl.

Images