A method for preparing a composite electrode based on binder fibrillation and electrodeposition

Abstract

The application belongs to the technical field of electrode preparation, and discloses a composite electrode preparation method based on binder fibrillation and electrodeposition, wherein the composite electrode preparation method comprises: in-situ fibrillation of a binder and uniform wrapping of an active material and a conductive agent, to obtain a self-supporting electrode with the active material wrapped by the filamentous binder; the thickness of the self-supporting electrode is controlled according to the unit area loading requirement of the active material; a closely combined metal current collector is grown on the obtained self-supporting electrode by electrochemical deposition, to obtain a composite electrode; the current and time during electrochemical deposition are set according to the mass proportion requirement of the metal current collector in the composite electrode. The technical scheme can prepare a composite electrode with controllable mass proportion and area of the metal current collector, and can improve the effective loading of the active material and the interface bonding force between the active material and the metal current collector.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrode preparation, and particularly relates to a composite electrode preparation method based on binder fibrillation and electrodeposition. BACKGROUND

[0002] With the increasing demand for high-performance energy storage devices, the research and development of electrode preparation technology have become a hot spot in the fields of material science and energy. Explanatorily, electrodes are the core components of electrochemical energy storage devices (such as lithium-ion batteries and supercapacitors) and electronic devices, and their performance directly affects the performance indicators of the devices, such as energy density, power density, cycle life, and safety.

[0003] At present, the existing electrode preparation processes mainly include wet electrode preparation processes and dry electrode preparation processes. In the wet electrode preparation process, a large amount of organic solvents, such as N-methyl pyrrolidone (NMP), need to be used, which are toxic and expensive, increasing the production cost and environmental burden. In the drying process, problems such as delamination and cracking are prone to occur, leading to the decrease of the mechanical properties and electrochemical properties of the electrode. The wet process is complex and has low efficiency, and it is difficult to prepare thick electrodes, which limits the improvement of energy density. The metal current collector (such as aluminum foil, copper foil, and nickel foam) also has many problems in terms of weight, cost, and interfacial adhesion. In the dry electrode preparation process, the active material, conductive agent, and binder are mixed under solvent-free conditions, and the self-supporting is formed by the fibrillation of the binder, and then the self-supporting is combined with the current collector. The process does not need to use organic solvents, reduces energy consumption and environmental pollution, can prepare thick electrodes, and improves the energy density and mechanical strength. However, there is still a problem of insufficient interfacial adhesion between the active material and the metal current collector, which affects the service life and reliability of the electrode.

[0004] In summary, in the existing electrode preparation processes, there are still problems of low loading of active material, low effective mass ratio, and insufficient interfacial adhesion between the active material and the metal current collector, which limits the improvement of electrode performance and affects the commercialization process of new technologies. SUMMARY

[0005] The present application aims to provide a composite electrode preparation method based on binder fibrillation and electrodeposition to solve one or more of the above technical problems. The technical solution disclosed in the present application has the characteristics of being able to prepare a composite electrode with controllable mass ratio and area of the metal current collector, improving the effective loading of the active material and the interfacial adhesion between the active material and the metal current collector, and the prepared electrode has a long service life and high reliability.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The application discloses a composite electrode preparation method based on binder fibrillation and electrodeposition.

[0008] The binder is fibrillated in situ and uniformly wrapped around the active material and the conductive agent to prepare a self-supporting electrode with the active material wrapped by the filamentous binder; wherein the thickness of the self-supporting electrode is controlled according to the unit area loading requirement of the active material;

[0009] A closely combined metal current collector is grown on the prepared self-supporting electrode by electrochemical deposition to prepare a composite electrode; wherein the current and time during the electrochemical deposition are set according to the mass proportion requirement of the metal current collector in the composite electrode.

[0010] The application further improves that the step of fibrillating the binder in situ and uniformly wrapping the active material and the conductive agent to prepare the self-supporting electrode with the active material wrapped by the filamentous binder comprises:

[0011] The active material, the binder and the conductive agent are selected according to requirements and are ultrasonically dispersed and constant-temperature dried in a culture dish according to the required mass ratio;

[0012] After drying, a proper amount of anhydrous ethanol is added, the mixture on the culture dish is gathered into a whole, and the whole after uniform mixing is rolled by a rolling machine to form the self-supporting electrode with a certain thickness and controllable loading.

[0013] The application further improves that the active material is a mixture of one or more of carbon-based materials, metal materials and conductive polymer materials.

[0014] The application further improves that the binder is a mixture of one or more of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene-ethylene copolymer, polyacrylic acid, polyimide and modified cellulose-based materials.

[0015] The application further improves that the conductive agent is a mixture of one or more of carbon-based conductive agents, metal-based conductive agents and composite conductive agents.

[0016] The application further improves that the material of the metal current collector is nickel, cobalt, aluminum or copper.

[0017] The application further improves that the step of growing the closely combined metal current collector on the prepared self-supporting electrode by electrochemical deposition to prepare the composite electrode comprises:

[0018] The electro-deposition solution is prepared; wherein the electro-deposition solution contains a deposition layer metal salt, a pH buffer and a surfactant;

[0019] The prepared self-supporting electrode is connected to the cathode of a direct current power supply, and the deposited metal sheet is connected to the anode of the direct current power supply.

[0020] The self-supporting electrode and the deposited metal sheet are placed in the prepared electrodeposition solution to perform electrochemical deposition of the metal current collector, so as to obtain a composite electrode with a metal current collector with a tightly combined interface and a controllable mass ratio.

[0021] Further improvement of the present application is that the deposited metal salt is a mixture of one or more of the following: a sulfate salt, a nitrate salt and a chloride salt of the deposited metal.

[0022] Further improvement of the present application is that the pH buffer is boric acid, formic acid, sodium citrate or sodium fluoroborate.

[0023] Further improvement of the present application is that the surfactant is a mixture of one or more of the following: sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and cetyltrimethylammonium bromide.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] In the technical scheme provided by the embodiments of the present application, the technical means of fibrillation of the binder combined with electrochemical deposition is used to realize the preparation of a composite electrode with a controllable mass ratio and area of the metal current collector, and the interface bonding force is improved, so that the prepared electrode has a long service life and high reliability. Specifically, in the present application, the thickness of the self-supporting electrode is adjusted to control the active material loading per unit area, and the electrode loading can also be changed according to actual needs. In addition, the present application uses the technical means of electrochemical deposition to prepare the metal current collector. Compared with the existing coating and pressing processes, the problem of insufficient interface bonding force between the active material and the current collector is greatly solved, which is conducive to the full play of the electrode performance. In the present application, the metal mass and area controllable loading are realized by setting the electrodeposition current and time, which can control the mass of the metal current collector, reduce the mass ratio of the metal current collector in the entire composite electrode, improve the energy density of the device, and have practical significance for industrial production.

[0026] Further specifically, the preparation process of the self-supporting electrode prepared by the present application is simple and easy to operate, only anhydrous ethanol is used, and no additional organic solvent is needed, which improves the efficiency and reduces the cost, and can effectively reduce the pollution and harm in the electrode preparation process. BRIEF DESCRIPTION OF DRAWINGS

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic flowchart of a method for preparing a composite electrode based on binder fibrillation and electrodeposition, as described in an embodiment of the present invention.

[0029] Figure 2 This is an optical image of the self-supporting electrode prepared in Example 1 of the present invention.

[0030] Figure 3 This is a scanning electron microscope image of the self-supporting electrode prepared in Example 1 of the present invention.

[0031] Figure 4 These are optical images of composite electrodes with different areas of metallic nickel electrodeposited in embodiments of the present invention.

[0032] Figure 5 This is a schematic diagram of the cyclic voltammetry curve of an alkaline (6M KOH) symmetrical supercapacitor assembled from a self-supporting electrode, a conventional foamed nickel current collector electrode, and an electrodeposited metallic nickel composite electrode prepared in Example 1 of this invention; wherein, the current density on the vertical axis is calculated based on the total mass of the positive and negative electrodes, including the mass of their respective positive and negative electrode active materials and the current collector matrix.

[0033] Figure 6 This is a schematic diagram comparing the specific capacitance and current density of an alkaline (6M KOH) symmetrical supercapacitor assembled from a self-supporting electrode, a conventional foamed nickel current collector electrode, and an electrodeposited metallic nickel composite electrode prepared in Example 1 of this invention; wherein, the horizontal axis current density and specific capacitance are calculated based on the total mass of the positive and negative electrodes, including the mass of their respective positive and negative electrode active materials and current collector matrix.

[0034] Figure 7 This is a schematic diagram of the electrochemical impedance of an alkaline (6M KOH) symmetric supercapacitor assembled from a self-supporting electrode, a conventional foamed nickel current collector electrode, and an electrodeposited metallic nickel composite electrode prepared in Example 1 of this invention.

[0035] Figure 8 This is a schematic diagram of the constant current charge-discharge curves of the alkaline (6M KOH) symmetrical supercapacitor assembled with a self-supporting electrode prepared in Example 1 of the present invention under different current densities.

[0036] Figure 9This is a schematic diagram of the constant current charge-discharge curves of an alkaline (6M KOH) symmetrical supercapacitor assembled with a conventional nickel foam current collector electrode under different current densities.

[0037] Figure 10 This is a schematic diagram of the constant current charge-discharge curves of the alkaline (6MKOH) symmetrical supercapacitor assembled by the electrodeposited nickel composite electrode prepared in Example 1 of the present invention under different current densities. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention; obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0039] Based on the technical solutions disclosed in the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0040] Please see Figure 1 This invention provides a method for preparing a composite electrode based on binder fibrillation and electrodeposition. Specifically, it is a method for preparing a composite electrode that achieves controllable metal current collector mass ratio and area based on binder fibrillation and electrodeposition, comprising the following steps:

[0041] Step 1: The binder is in-situ fiberized and uniformly coated with active material and conductive agent to prepare a self-supporting electrode with active material wrapped by filamentous binder; wherein, the thickness of the self-supporting electrode is controlled according to the unit area loading requirement of active material; explanatoryly, the areal density of the self-supporting electrode can be effectively controlled by the thickness during rolling in a roll press.

[0042] Step 2: Using electrochemical deposition, a tightly bonded metal current collector is grown on the self-supporting electrode obtained in Step 1 to prepare a composite electrode; wherein, the current and time during electrochemical deposition are set according to the required mass ratio of the metal current collector in the composite electrode; interpretably, the metal mass density of electrochemical deposition can be controlled by deposition current and time.

[0043] In one embodiment of the present application, the step 1 performs in-situ fiberization of the binder and uniformly wraps the active material and the conductive agent to prepare a self-supporting electrode with the active material wrapped by the filamentous binder, and the step can specifically include:

[0044] The active material, the binder and the conductive agent are ultrasonically dispersed in a petri dish according to the required mass ratio, and dried on a constant temperature platform;

[0045] After drying, a proper amount of alcohol is added, and the mixture on the petri dish is gathered into a whole body using a micro-spatula, and the uniformly mixed whole body is rolled by a rolling machine to form a self-supporting electrode with a certain thickness and a controllable loading capacity.

[0046] In one embodiment of the present application, the step 2 performs the growth of a closely combined metal current collector on the self-supporting electrode prepared in the step 1 by electrochemical deposition to prepare a composite electrode, and the step can include:

[0047] The electro-deposition solution is prepared, wherein the electro-deposition solution contains a deposition layer metal salt, a pH buffer and a surfactant;

[0048] The flexible self-supporting electrode prepared in the step 1 is connected to the cathode of a direct current power supply, and the deposition layer metal sheet is connected to the anode of the direct current power supply; the self-supporting electrode and the deposition layer metal sheet are placed in the electro-deposition solution prepared above to perform electrochemical deposition of the metal current collector, thereby obtaining a composite electrode with a closely combined metal current collector and a controllable mass of the metal current collector.

[0049] In a further preferred technical solution of the embodiment of the present application, the active material includes one or a mixture of several of carbon-based materials, metal materials, conductive polymers and the like. Further, the binder is one or a mixture of several of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene-ethylene copolymer, polyacrylic acid, polyimide, modified cellulose-based binder and the like. Further, the conductive agent is one or a mixture of several of carbon-based conductive agent, metal-based conductive agent, composite conductive agent and the like. The metal current collector obtained by electrochemical deposition is nickel, cobalt, aluminum or copper and the like.

[0050] In a further preferred technical solution of the embodiment of the present application, the deposition layer metal salt in the electro-deposition solution is one or a mixture of several of sulfate, nitrate or chloride of the deposition layer metal. The pH buffer is boric acid, formic acid, sodium citrate or sodium fluoroborate; and the surfactant is a mixture of one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, cetyltrimethylammonium bromide and the like.

[0051] In the specific disclosed technical solutions of the embodiment of the present application, in the process of preparing the self-supporting electrode, the binder fibrillation technology is adopted, which makes the preparation process of the electrode simple and easy to operate, greatly improving the production efficiency. Only anhydrous ethanol is used as the solvent in the entire preparation process, avoiding the use of additional organic solvents, which not only reduces the production cost, but also effectively reduces the environmental pollution and harm in the electrode preparation process, in line with the green and environmentally friendly production concept. In addition, by adjusting the calendering thickness of the rolling machine, the loading of the active material on the unit area can be accurately controlled. This feature allows the loading of the electrode to be flexibly adjusted according to actual needs, meeting the needs of different application scenarios. Furthermore, the present application uses electrochemical deposition technology to prepare the metal current collector, which greatly solves the problem of insufficient bonding force between the active material and the current collector in the traditional method, ensuring the full play of the electrode performance. The electrochemical deposition technology also allows precise control of the quality of the current collector, thereby reducing the mass fraction of the current collector in the entire composite electrode. This improvement significantly improves the energy density of the device, making the electrode exhibit more excellent performance in energy storage and conversion.

[0052] The technical solution proposed by the embodiment of the present application not only has theoretical innovation, but also has strong practical industrial production significance. The simple preparation process, low-cost production method and controllable electrode performance make this technical solution have a wide application prospect in industrial production.

[0053] In summary, the technical solution provided by the embodiment of the present application realizes efficient, environmentally friendly and controllable preparation of the composite electrode through the combination of binder fibrillation and electrochemical deposition technology. This technical solution not only improves the performance and energy density of the electrode, but also provides strong technical support for industrial production.

[0054] In the embodiment of the present application, the following specific examples are used for test verification:

[0055] Example 1:

[0056] The preparation method of the embodiment of the present application includes the following processes:

[0057] Step 1, weigh 850mg of activated carbon, 50mg of polytetrafluoroethylene, 100mg of acetylene black, and add an appropriate amount of alcohol to ultrasonically disperse in a culture dish, and dry on a 80℃ constant temperature heating table; then drop an appropriate amount of alcohol, and use a spatula to gather the mixture on the culture dish into a whole, and pass the whole after uniform mixing into a lump through a rolling machine with adjusted thickness to form a self-supporting electrode with uniform thickness.

[0058] Step 2, weigh 12g of NiSO4·6H2O, 2g of H3BO3 and 0.005g of C 12 H 25SO4Na was added into 50 mL deionized water and dissolved to prepare a uniform and transparent electrodeposition solution; the self-supporting electrode prepared in step 1 was connected to the cathode of a direct current power supply, a nickel sheet was connected to the anode, and the electrode was immersed in the prepared electrodeposition solution; an electrodeposition current of 50 mA·cm -1 was set, and the time was 5 min, thereby obtaining a self-supporting electrode and a composite electrode of metal nickel.

[0059] In the specific embodiments of the present application, based on the property that the binder can form a micro-fiber network structure under the action of high shear force, the electrode material (such as active material, conductive agent, etc.) is tightly bonded together to form a self-supporting electrode with controllable loading; on this basis, the metal current collector is deposited by using the electrochemical deposition technology, and the thickness and uniformity of the deposited layer of metal can be accurately controlled by adjusting the current density, electrolyte composition and deposition time, thereby realizing the tight combination of the electrode material and the current collector, and reducing the mass ratio of the current collector. In summary, the preparation method disclosed in the embodiments of the present application is more convenient and simple to operate, has lower cost and hazard, and has a wider practical application value. In the exemplary technical solutions, the electrodeposition current can be adjusted between 10 to 100 mA·cm -1 , and the time can be adjusted between 1 to 20 min.

[0060] Please refer to Figures 2 to 10 for a detailed analysis and description of the embodiments of the present application.

[0061] Figure 2 is an optical picture of the self-supporting electrode prepared in Example 1 of the present application, and it can be observed that the surface of the self-supporting electrode is smooth and flat, which meets the basic requirements of the electrode application, thereby proving the feasibility of preparing the self-supporting electrode with the assistance of anhydrous ethanol.

[0062] Figure 3 is a scanning electron microscope picture of the self-supporting electrode prepared in Example 1 of the present application, and it can be seen from the picture that the filamentous binder wraps the solid substances such as active materials, thereby proving that the binder can indeed be in situ fiberized by calendering with the assistance of anhydrous ethanol.

[0063] Figure 4 is an optical picture of the composite electrode of electrodeposited metal nickel with different areas in the embodiments of the present application, and it can be proved from the picture that the electrodeposition can accurately realize the controllable area of the current collector.

[0064] Figure 5 is a cyclic voltammogram of the alkaline (6M KOH) symmetrical supercapacitor assembled by the self-supporting electrode prepared in Example 1, the conventional foam nickel current collector electrode and the composite electrode of electrodeposited metal nickel in the embodiments of the present application; wherein the current density of the vertical axis is calculated based on the total mass of the positive and negative electrodes, including the mass of the active materials and the current collector substrate of the positive and negative electrodes; from the picture, it can be seen that the self-supporting electrode prepared in Example 1 has a good electrochemical performance, which is close to that of the composite electrode of electrodeposited metal nickel.Figure 5 It can be seen that the cyclic voltammogram of the symmetric supercapacitor assembled by the composite electrode is close to a rectangle, indicating that the electrode mainly exhibits a capacitive behavior in the charging and discharging process, and reflecting that the electrode material has good electrochemical reversibility and fast ion adsorption and desorption capacity; the area surrounded by the curve is proportional to the electrode capacitance, and it can be concluded that the composite electrode based on the fibrillation of the binder and the electrodeposition is obviously better than the conventional foam nickel current collector electrode under the same conditions, and slightly better than the self-supporting electrode without the electrodeposition of the current collector, thereby proving the necessity of the current collector and the advantages of the electrode preparation method.

[0065] Figure 6 In the embodiment of the present application, the specific capacitance and current density relationship of the alkaline (6M KOH) symmetric supercapacitors assembled by the self-supporting electrode prepared in Example 1, the conventional foam nickel current collector electrode and the composite electrode of the electrodeposited metal nickel are compared; wherein the horizontal axis current density and the vertical axis specific capacitance are calculated based on the total mass of the positive and negative electrodes, including the mass of the respective positive and negative active materials and the current collector substrate. It can be seen from Figure 6 that the composite electrode based on the fibrillation of the binder and the electrodeposition has a specific capacitance of 40.7 F g -1 at 0.1 A g -1 of the total mass of the positive and negative electrodes, and a specific capacitance of 21 F g -1 at 3 A g -1 of the total mass of the positive and negative electrodes, which is obviously better than the conventional foam nickel current collector electrode under the same conditions, and slightly better than the self-supporting electrode without the electrodeposition of the current collector, thereby proving the necessity of the current collector and the advantages of the electrode preparation method.

[0066] Figure 7 In the embodiment of the present application, the electrochemical impedance diagram of the alkaline (6M KOH) symmetric supercapacitors assembled by the self-supporting electrode prepared in Example 1, the conventional foam nickel current collector electrode and the composite electrode of the electrodeposited metal nickel is shown. It can be seen that the ohmic resistance and the interface transfer resistance of the composite electrode based on the fibrillation of the binder and the electrodeposition are smaller, which corresponds to the excellent electrochemical performance.

[0067] Figure 8 In the embodiment of the present application, the constant current charge and discharge curves of the alkaline (6M KOH) symmetric supercapacitors assembled by the self-supporting electrode prepared in Example 1 under different current densities are shown. Compared with Figure 10 , the charging and discharging time is slightly shortened under the same current density, and the rate performance is slightly lower than the composite electrode based on the fibrillation of the binder and the electrodeposition, thereby proving the necessity of the current collector and the advantages of the electrode preparation method.

[0068] Figure 9are the constant current charge-discharge curves of the symmetrical supercapacitor of the alkaline (6M KOH) assembled by the conventional foamed nickel current collector electrode at different current densities. Figure 10 In contrast, the charge-discharge time is significantly shortened at the same current density, and the rate performance is significantly lower than that of the composite electrode based on the binder fibrillation and electrodeposition, thus proving the advantages of the composite electrode preparation method.

[0069] Figure 10 are the constant current charge-discharge curves of the symmetrical supercapacitor of the alkaline (6M KOH) assembled by the electrodeposited metal nickel composite electrode prepared in Example 1 at different current densities. Under the condition of constant current charge-discharge, the change of voltage with time shows a clear linear relationship, and the charge-discharge curve has a clear triangular symmetry distribution, indicating that the reaction of the composite electrode is mainly the charge transfer on the double-layer capacitor, and the electrode material has good electrochemical reversibility.

[0070] Example 2:

[0071] The preparation method of the embodiment of the application comprises the following processes:

[0072] Step 1, weigh 850 mg of activated carbon, 50 mg of polytetrafluoroethylene, 100 mg of acetylene black, and add an appropriate amount of alcohol to ultrasonically disperse in a culture dish, and dry on an 80℃ constant temperature heating table; then drop an appropriate amount of alcohol, and use a spatula to gather the mixture on the culture dish into a whole, and pass the whole after uniform mixing into a group through an adjusted thickness roll mill for calendering to form an activated carbon self-supporting electrode with uniform thickness.

[0073] Step 2, weigh 12 g of CuSO4·6H2O, 2 g of H3BO3 and 0.005 g of C 12 H 25 SO4Na into 50 mL of deionized water, and fully dissolve to prepare a uniform transparent electrodeposition solution; connect the self-supporting electrode prepared above to the cathode of a direct current power supply, connect a copper sheet to the anode, and immerse in the electrodeposition solution prepared above, set the electrodeposition current to 50 mA·cm -1 , and the time to 5 min, to obtain a composite electrode of activated carbon self-supporting electrode and metal copper.

[0074] Example 3:

[0075] The preparation method of the embodiment of the application comprises the following processes:

[0076] Step 1, take 850mg activated carbon, 50mg polytetrafluoroethylene, 100mg acetylene black, and add an appropriate amount of alcohol to ultrasonic dispersion in a culture dish, and dry on a constant temperature heating table at 80℃; then drop an appropriate amount of alcohol, and use a spatula to gather the mixture on the culture dish into a whole, and pass the whole after uniform mixing into a ball through a roll press with adjusted thickness to perform calendering, so as to form an activated carbon self-supporting electrode with uniform thickness.

[0077] Step 2, take 12g Al2(SO4)3·6H2O, 2g H3BO3 and 0.005g C 12 H 25 SO4Na into 50mL deionized water, and fully dissolve to prepare a uniform transparent electrodeposition solution; connect the self-supporting electrode prepared above to the cathode of a direct current power supply, connect an aluminum sheet to the anode, immerse in the electrodeposition solution prepared above, set the electrodeposition current to 50mA·cm -1 , and the time to 5min, so as to obtain a composite electrode of an activated carbon self-supporting electrode and metal aluminum.

[0078] Example 4:

[0079] The preparation method of the embodiment of the present application includes the following processes:

[0080] Step 1, take 800mg graphite, 100mg nanocellulose, 100mg super p, and add an appropriate amount of alcohol to ultrasonic dispersion in a culture dish, and dry on a constant temperature heating table at 80℃; then drop an appropriate amount of alcohol, and use a spatula to gather the mixture on the culture dish into a whole, and pass the whole after uniform mixing into a ball through a roll press with adjusted thickness to perform calendering, so as to form a self-supporting electrode with uniform thickness.

[0081] Step 2, take 12g CuSO4·6H2O, 2g H3BO3 and 0.005g C 12 H 25 SO4Na into 50mL deionized water, and fully dissolve to prepare a uniform transparent electrodeposition solution; connect the self-supporting electrode prepared above to the cathode of a direct current power supply, connect a copper sheet to the anode, immerse in the electrodeposition solution prepared above, set the electrodeposition current to 50mA·cm -1 , and the time to 3min, so as to obtain a composite electrode of a self-supporting electrode and metal copper.

[0082] Example 5:

[0083] The preparation method of the embodiment of the present application includes the following processes:

[0084] Step 1, take 800mg graphite, 100mg nanocellulose, 100mg super p, and add an appropriate amount of alcohol to ultrasonic dispersion in a petri dish, and dry on a constant temperature heating table at 80 DEG C; then drop an appropriate amount of alcohol, and use a spatula to gather the mixture on the petri dish into a whole, and pass the whole after uniform mixing into a roll mill with an adjusted thickness to perform calendering, to form a self-supporting electrode with uniform thickness.

[0085] Step 2, take 12g CuSO4·6H2O, 2g H3BO3 and 0.005g C 12 H 25 SO4Na into 50mL deionized water, and fully dissolve to prepare a uniform transparent electrodeposition solution; connect the self-supporting electrode prepared above to a cathode of a direct current power supply, connect a copper sheet to an anode, immerse in the electrodeposition solution prepared above, set an electrodeposition current of 50mA·cm -1 , and a time of 5min, to obtain a self-supporting electrode and a composite electrode of metal copper.

[0086] Example 6:

[0087] The preparation method of the embodiment of the application includes the following processes:

[0088] Step 1, take 800mg graphite, 100mg nanocellulose, 100mg super p, and add an appropriate amount of alcohol to ultrasonic dispersion in a petri dish, and dry on a constant temperature heating table at 80 DEG C; then drop an appropriate amount of alcohol, and use a spatula to gather the mixture on the petri dish into a whole, and pass the whole after uniform mixing into a roll mill with an adjusted thickness to perform calendering, to form a self-supporting electrode with uniform thickness.

[0089] Step 2, take 12g CuSO4·6H2O, 2g H3BO3 and 0.005g C 12 H 25 SO4Na into 50mL deionized water, and fully dissolve to prepare a uniform transparent electrodeposition solution. Connect the self-supporting electrode to a cathode of a direct current power supply, connect a copper sheet to an anode, immerse in the electrodeposition solution prepared above, set an electrodeposition current of 50mA·cm -1 , and a time of 7min, to obtain a self-supporting electrode and a composite electrode of metal copper.

[0090] Example 7:

[0091] The preparation method of the embodiment of the application includes the following processes:

[0092] Step 1, take 800 mg of a mixture of graphite and activated carbon, 100 mg of a mixture of ethylene-tetrafluoroethylene copolymer and polytetrafluoroethylene-ethylene copolymer, 100 mg of super p, and add an appropriate amount of alcohol to ultrasonic dispersion in a petri dish, and dry on an 80°C constant temperature heating table; then drop an appropriate amount of alcohol, and use a spatula to gather the mixture on the petri dish into a whole, and pass the whole after uniform mixing into a roll to calender, to form a self-supporting electrode with uniform thickness.

[0093] Step 2, take 12 g of CuSO4·6H2O, 2 g of H3BO3, and 0.005 g of C 12 H 25 SO4Na into 50 mL of deionized water, and dissolve to prepare a uniform transparent electrodeposition solution. Connect the above self-supporting electrode to the cathode of a direct current power supply, connect a copper sheet to the anode, and immerse in the above prepared electrodeposition solution, and set the electrodeposition current to 50 mA·cm -1 , and the time to 7 min, to obtain a self-supporting electrode and a composite electrode of metal copper.

[0094] In summary, the embodiment of the present application provides a composite electrode preparation method based on binder fibrillation and electrodeposition, specifically relates to an electrode preparation method based on binder fibrillation and electrodeposition to realize controllable mass of metal current collector, mainly including two parts: through in-situ fibrillation of the binder and uniform wrapping of the active material and the conductive agent, a self-supporting electrode with active material wrapped by filamentous binder is prepared; and according to requirements, a metal current collector with close combination and controllable mass area is grown on the self-supporting electrode through electrochemical deposition. The steps for preparing the self-supporting electrode in the embodiment of the present application are simple and easy to operate, high in efficiency and low in cost, and the electrode loading can be changed according to actual requirements; the technical means of electrochemical deposition greatly solves the problem that the performance cannot be fully played due to insufficient combination force of the active material and the current collector, reduces the mass proportion of the current collector in the whole electrode, and improves the energy density of the device.

[0095] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A method for preparing a composite electrode based on binder fibrillation and electrodeposition, characterized in that, The method comprises the following steps: in-situ fiberizing the binder and uniformly wrapping the active material and the conductive agent to prepare a self-supporting electrode with the active material wrapped by the filamentous binder; growing a closely combined metal current collector on the prepared self-supporting electrode by electrochemical deposition to prepare a composite electrode; wherein the current and time during the electrochemical deposition are set according to the mass proportion of the metal current collector in the composite electrode.

2. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 1, characterized in that, The step of in-situ fiberizing the binder and uniformly wrapping the active material and the conductive agent to prepare a self-supporting electrode with the active material wrapped by the filamentous binder comprises: selecting the active material, the binder and the conductive agent according to requirements, and ultrasonically dispersing and constant-temperature drying the mixture in a culture dish according to the required mass ratio; after drying, adding an appropriate amount of anhydrous ethanol, agglomerating the mixture on the culture dish into a whole, and passing the uniformly mixed whole through a roll press to form a self-supporting electrode with a certain thickness and a controllable loading.

3. The method for preparing a binder-fibrillated and electrodeposited composite electrode according to claim 1, wherein The active material is a mixture of one or more of carbon-based materials, metal materials and conductive polymer materials.

4. The method for preparing a binder-fibrillated and electrodeposited composite electrode according to claim 1, wherein The binder is a mixture of one or more of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene-ethylene copolymer, polyacrylic acid, polyimide and modified cellulose-based materials.

5. The method of claim 1, wherein the method is characterized by, The conductive agent is a mixture of one or more of carbon-based conductive agents, metal-based conductive agents and composite conductive agents.

6. The method for preparing a binder-fibrillated and electrodeposited composite electrode according to claim 1, wherein The material of the metal current collector is nickel, cobalt, aluminum or copper.

7. The method of claim 1, wherein the method is characterized by, The step of growing a closely combined metal current collector on the prepared self-supporting electrode by electrochemical deposition to prepare a composite electrode comprises: preparing an electrodeposition solution; wherein the electrodeposition solution contains a deposition layer metal salt, a pH buffer and a surfactant; connecting the prepared self-supporting electrode to the cathode of a direct current power supply and connecting a deposition layer metal sheet to the anode of the direct current power supply; placing the self-supporting electrode and the deposition layer metal sheet into the prepared electrodeposition solution to perform electrochemical deposition of the metal current collector, thereby obtaining a composite electrode with a closely combined interface and a controllable mass proportion of the metal current collector.

8. The method for preparing a binder-fibrillated and electrodeposited composite electrode according to claim 7, wherein The deposition layer metal salt is a mixture of one or more of sulfate, nitrate and chloride of the deposition layer metal.

9. The method of claim 7, wherein the method is characterized by, The pH buffer is boric acid, formic acid, sodium citrate or sodium fluoroborate.

10. The method of claim 7, wherein the method is characterized by, The surfactant is a mixture of one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and cetyltrimethylammonium bromide.

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