Composite electrode preparation method based on binder fibrillation and electrodeposition

Abstract

The invention belongs to the technical field of electrode preparation, and discloses a composite electrode preparation method based on binder fibrillation and electrodeposition. The preparation method of the composite electrode comprises the following steps: carrying out in-situ fibrosis on a binder, and uniformly wrapping an active material and a conductive agent, so as to prepare a self-supporting electrode with the active material wound and wrapped by the filamentous binder; wherein the thickness of the self-supporting electrode is controlled according to the unit area load demand of the active material; an electrochemical deposition mode is adopted, a tightly combined metal current collector grows on the prepared self-supporting electrode, and a composite electrode is prepared; wherein the current and time during electrochemical deposition are set according to the mass ratio requirement of the metal current collector in the composite electrode. According to the technical scheme, the composite electrode with the controllable mass ratio and area of the metal current collector can be prepared, and the effective loading capacity of the active material and the interface bonding force between the active material and the metal current collector can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrode preparation, and particularly relates to a method for preparing a composite electrode based on binder fibrillation and electrodeposition. Background Art

[0002] With the increasing demand for high-performance energy storage devices, the research and development of electrode preparation technology have become a hot topic in the fields of materials science and energy; explanatorily, the electrode is the core component of electrochemical energy storage devices (such as lithium-ion batteries, supercapacitors) and electronic devices, and its performance directly affects performance indicators such as the energy density, power density, cycle life, and safety of the devices.

[0003] Currently, 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-methylpyrrolidone (NMP), etc., are required, which are toxic and expensive, increasing the production cost and environmental burden; problems such as delamination and cracking are likely to occur during the drying process, resulting in a decline in 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, restricting the improvement of energy density; metal current collectors (such as aluminum foil, copper foil, nickel foam, etc.) also have many problems in terms of weight, cost, interfacial adhesion, etc. In the dry electrode preparation process, the active material, conductive agent, and binder are mixed under solvent-free conditions, and self-support is formed by the fibrillation of the binder, and then it is compounded with the current collector. It does not require the use of organic solvents, reducing energy consumption and environmental pollution, and can prepare thick electrodes, improving energy density and mechanical strength, but there is still a problem of insufficient interfacial binding force between the active material and the current collector, affecting the service life and reliability of the electrode.

[0004] In summary, in the existing electrode preparation processes, there are still problems such as a low loading of the active material, a low effective mass ratio, and insufficient interfacial binding force between the active material and the metal current collector, restricting the improvement of electrode performance and also affecting the commercialization process of new technologies. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a composite electrode based on binder fibrillation and electrodeposition to solve one or more of the above-mentioned technical problems. The characteristics of the technical solution disclosed by the present invention are that it can prepare a composite electrode with a controllable mass ratio and area of the metal current collector, can improve the effective loading of the active material and the interfacial binding force 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 object, the present invention adopts the following technical solutions: A method for preparing a composite electrode based on binder fibrillation and electrodeposition, disclosed by the present invention, comprises the following steps: Fibrillate the binder in situ and uniformly wrap the active material and the conductive agent to prepare a self-supporting electrode with filamentous binder winding and wrapping the active material; wherein, control the thickness of the self-supporting electrode according to the loading requirement per unit area of the active material; Adopt an electrochemical deposition method to grow a tightly bonded metal current collector on the prepared self-supporting electrode to prepare a composite electrode; wherein, set the current and time during electrochemical deposition according to the mass ratio requirement of the metal current collector in the composite electrode.

[0007] A further improvement of the present invention lies in that the step of fibrillating the binder in situ and uniformly wrapping the active material and the conductive agent to prepare a self-supporting electrode with filamentous binder winding and wrapping the active material comprises: Select the active material, binder and conductive agent according to requirements, and ultrasonically disperse and dry at a constant temperature in a petri dish according to the required mass ratio; After drying, add an appropriate amount of absolute ethanol, agglomerate the mixture on the petri dish into a whole, and roll the uniformly mixed whole through a roll press to form a self-supporting electrode with a certain thickness and controllable loading.

[0008] A further improvement of the present invention lies in that the active material is a mixture of one or more of carbon-based materials, metal materials and conductive polymer materials.

[0009] A further improvement of the present invention lies in 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.

[0010] A further improvement of the present invention lies in that the conductive agent is a mixture of one or several of carbon-based conductive agents, metal-based conductive agents and composite conductive agents.

[0011] A further improvement of the present invention lies in that the material of the metal current collector is nickel, cobalt, aluminum or copper.

[0012] A further improvement of the present invention lies in that the step of adopting an electrochemical deposition method to grow a tightly bonded metal current collector on the prepared self-supporting electrode to prepare a composite electrode comprises: Prepare an electrodeposition solution; wherein, the electrodeposition solution contains a metal salt of the deposition layer, a pH buffer and a surfactant; Connect the prepared self-supporting electrode to the cathode of a DC power supply, and connect the metal sheet of the deposition layer to the anode of the DC power supply; Place the self-supporting electrode and the deposited layer metal sheet into the electroplating solution obtained by formulation, and conduct electrochemically deposition of the metal current collector to obtain a composite electrode with a metal current collector having a tightly bonded interface and a controllable mass ratio.

[0013] A further improvement of the present invention lies in that the deposited layer metal salt is a mixture of one or more of sulfates, nitrates, and chlorides of the deposited layer metal.

[0014] A further improvement of the present invention lies in that the pH buffer is boric acid, formic acid, sodium citrate, or sodium fluoroborate.

[0015] A further improvement of the present invention lies in that the surfactant is a mixture of one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and cetyltrimethylammonium bromide.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In the technical solution provided by the embodiment of the present invention, through the technical means of fibrillization of the binder combined with electrochemical deposition, the preparation of a composite electrode with a controllable mass ratio and area of the metal current collector is realized, and at the same time, the interfacial bonding force can be improved, so that the prepared electrode has a long service life and high reliability. Specifically, in the present invention, the unit area loading of the active material can be controlled by adjusting the thickness of the self-supporting electrode, and the electrode loading can also be changed according to actual needs; in addition, the present invention uses the technical means of electrochemical deposition to prepare the metal current collector. Compared with the existing processes such as coating and pressing, the problem of insufficient interfacial bonding force between the active material and the current collector is solved to a great extent, which is beneficial to the full play of the electrode performance; in the present invention, by setting the electroplating current and time for controllable loading of the metal mass and area, the mass of the metal current collector can be controlled, the mass ratio of the metal current collector in the entire composite electrode can be reduced, the energy density of the device can be increased, and it has practical significance for industrial production.

[0017] Further specifically, the preparation process of the self-supporting electrode of the present invention is simple and easy to operate, only using anhydrous ethanol without using any additional organic solvents, which improves the efficiency and reduces the cost, and can effectively reduce the pollution and harm in the electrode preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art; obviously, the drawings in the following description are some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0019] Figure 1It is a schematic flow chart of a method for preparing a composite electrode based on binder fibrillation and electrodeposition in an embodiment of the present invention; Figure 2 It is an optical picture of the self-supporting electrode prepared in Embodiment 1 of the present invention.

[0020] Figure 3 It is a scanning electron microscope image of the self-supporting electrode prepared in Embodiment 1 of the present invention.

[0021] Figure 4 It is an optical picture of a composite electrode with different areas of electrodeposited metallic nickel in an embodiment of the present invention.

[0022] Figure 5 It is a schematic cyclic voltammetry curve of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Embodiment 1, a conventional nickel foam current collector electrode, and a composite electrode with electrodeposited metallic nickel in an embodiment of the present invention; wherein, the current density on the vertical axis is calculated based on the total mass of the positive and negative electrodes, including the masses of the respective positive and negative active materials and the current collector matrix.

[0023] Figure 6 It is a schematic comparison diagram of the relationship between the specific capacitance and the current density of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Embodiment 1, a conventional nickel foam current collector electrode, and a composite electrode with electrodeposited metallic nickel in an embodiment of the present invention; wherein, the current density and the specific capacitance on the horizontal axis are calculated based on the total mass of the positive and negative electrodes, including the masses of the respective positive and negative active materials and the current collector matrix.

[0024] Figure 7 It is an electrochemical impedance schematic diagram of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Embodiment 1, a conventional nickel foam current collector electrode, and a composite electrode with electrodeposited metallic nickel in an embodiment of the present invention.

[0025] Figure 8 It is a schematic diagram of the constant current charge-discharge curves at different current densities of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Embodiment 1 in an embodiment of the present invention.

[0026] Figure 9 It is a schematic diagram of the constant current charge-discharge curves at different current densities of an alkaline (6M KOH) symmetric supercapacitor assembled with a conventional nickel foam current collector electrode.

[0027] Figure 10 It is a schematic diagram of the constant current charge-discharge curves at different current densities of an alkaline (6M KOH) symmetric supercapacitor assembled with the composite electrode with electrodeposited metallic nickel prepared in Embodiment 1 in an embodiment of the present invention. Detailed implementation manners

[0028] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments of the technical solutions are part of the embodiments of the present invention, rather than all of the embodiments.

[0029] Based on the technical solutions disclosed in the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that comprises a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0030] Please refer to Figure 1 , a method for preparing a composite electrode based on binder fibrillation and electrodeposition provided by an embodiment of the present invention is specifically a method for preparing a composite electrode based on binder fibrillation and electrodeposition to control the mass ratio and area of a metal current collector, and includes the following steps: Step 1: In-situ fibrillate the binder and uniformly wrap the active material and the conductive agent to prepare a self-supporting electrode with a filamentous binder wound around and wrapping the active material; wherein, the thickness of the self-supporting electrode is controlled according to the unit area loading requirement of the active material; explanatorily, the areal density of the self-supporting electrode can be effectively controlled by the thickness during rolling with a roller press; Step 2: Adopt an electrochemical deposition method to grow a tightly bonded metal current collector on the self-supporting electrode prepared in Step 1 to prepare a composite electrode; wherein, the current and time during electrochemical deposition are set according to the mass ratio requirement of the metal current collector in the composite electrode; explanatorily, the mass density of the electrochemically deposited metal can be controlled by the deposition current and time.

[0031] In a specific embodiment of the present invention, the steps of Step 1 for in-situ fibrillating the binder and uniformly wrapping the active material and the conductive agent to prepare a self-supporting electrode with a filamentous binder wound around and wrapping the active material may specifically include: Disperse the active material, binder, and conductive agent in a petri dish by ultrasonic wave according to the required mass ratio as needed, and dry it on a constant temperature platform; After drying, add an appropriate amount of alcohol, use a micro spatula to gather the mixture on the petri dish into a whole, and roll the uniformly mixed whole through a roller press to form a self-supporting electrode with a certain thickness and controllable loading.

[0032] In a specific embodiment of the present invention, step 2 is performed by electrochemically depositing a tightly bound metal current collector on the self-supporting electrode prepared in step 1. The steps for preparing the composite electrode may include: Preparing an electroplating solution; wherein, the electroplating solution contains a metal salt of the deposition layer, a pH buffer, and a surfactant; Connect the flexible self-supporting electrode prepared in step 1 to the cathode of a DC power supply, and connect the metal sheet of the deposition layer to the anode of the DC power supply; place the self-supporting electrode and the metal sheet of the deposition layer into the above-prepared electroplating solution, and perform electrochemical deposition of the metal current collector to obtain a composite electrode with tight binding and controllable mass of the metal current collector.

[0033] In a further preferred technical solution of the embodiment of the present invention, the active material includes one or a mixture of several of carbon-based materials, metal materials, conductive polymers and other materials. Further, the binder is one or a mixture of several of binders such as polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene-ethylene copolymer, polyacrylic acid, polyimide, modified cellulose-based, etc. Further, the conductive agent is one or a mixture of several of conductive agents such as carbon-based conductive agents, metal-based conductive agents, composite conductive agents, etc. The metal current collector obtained by electrochemical deposition is nickel, cobalt, aluminum, copper, etc.

[0034] In a further preferred technical solution of the embodiment of the present invention, the metal salt of the deposition layer in the electroplating solution is one or a mixture of sulfates, nitrates or chlorides of the metal of the deposition layer. The pH buffer is boric acid, formic acid, sodium citrate or sodium fluoroborate; the surfactant is one or a mixture of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, cetyltrimethylammonium bromide.

[0035] In the technical solution specifically disclosed in the embodiments of the present invention, during the preparation of the self-supporting electrode, the binder fibrillation technology is adopted. This technology makes the electrode preparation process simple and easy to operate, greatly improving the production efficiency. During the entire preparation process, only anhydrous ethanol is used as the solvent, avoiding the use of additional organic solvents. This not only reduces the production cost but also effectively reduces the environmental pollution and harm during the electrode preparation process, conforming to the green and environmental protection production concept. In addition, by adjusting the calendering thickness of the calender, the loading of the active material per unit area can be accurately controlled. This characteristic enables the loading of the electrode to be flexibly adjusted according to actual needs, meeting the requirements of different application scenarios. Furthermore, the present invention adopts the electrochemical deposition technology to prepare the metal current collector. This technology greatly solves the problem of insufficient binding 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 ratio of the current collector in the entire composite electrode. This improvement significantly increases the energy density of the device, making the electrode exhibit more excellent performance in energy storage and conversion.

[0036] The technical solution proposed in the embodiments of the present invention 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 all make this technical solution have a wide application prospect in industrial production.

[0037] In summary, the technical solution provided by the embodiments of the present invention realizes the efficient, environmental protection, and controllable preparation of the composite electrode through the technical means of binder fibrillation combined with electrochemical deposition. This technical solution not only improves the performance and energy density of the electrode but also provides strong technical support for industrial production.

[0038] In the embodiments of the present invention, the following specific examples are used for experimental verification: Example 1: The preparation method of the embodiments of the present invention includes the following processes: Step 1, weigh 850 mg of activated carbon, 50 mg of polytetrafluoroethylene, and 100 mg of acetylene black, add an appropriate amount of alcohol, ultrasonically disperse them in a petri dish, and dry them on a constant temperature heating table at 80 °C; then drop an appropriate amount of alcohol, use a scraper to gather the mixture on the petri dish into a whole, and calender the whole after uniform mixing into a mass through a calender with adjusted thickness to form a self-supporting electrode with uniform thickness.

[0039] Step 2, weigh 12 g of NiSO 4 ·6H 2 O, 2 g of H 3 BO 3 and 0.005 g of C 12 H25 SO 4 Na is added to 50 mL of deionized water and fully dissolved to prepare a homogeneous and transparent electrodeposition solution; the self-supporting electrode prepared in step 1 is connected to the cathode of a DC power supply, and a nickel sheet is connected to the anode, and they are immersed in the prepared electrodeposition solution. Set the electrodeposition current to 50 mA·cm -1 , and the time to 5 min, then a composite electrode of the self-supporting electrode and metallic nickel is obtained.

[0040] In specific embodiments of the present invention, based on the property that the binder forms a microfiber network structure under high shear force, electrode materials (such as active materials, conductive agents, etc.) are tightly bonded together to form a self-supporting electrode with controllable loading; on this basis, using electrochemical deposition technology to deposit a metal current collector, adjusting the current density, electrolyte composition, deposition time, etc., can precisely control the thickness and uniformity of the deposited layer metal, realizing the tight combination of the electrode material and the current collector, and at the same time being able to reduce the mass ratio of the current collector. Summarizing, the preparation method disclosed in the embodiments of the present invention is more convenient and simple to operate and has lower cost and harm compared with the existing electrode preparation methods, showing a wider practical application value. In an exemplary technical solution, the electrodeposition current can be adjusted between 10 and 100 mA·cm -1 , and the time can be adjusted between 1 and 20 min.

[0041] Please refer to Figures 2 to 10 for a detailed analysis and description of the embodiments of the present invention.

[0042] Figure 2 is an optical picture of the self-supporting electrode prepared in Example 1 of the present invention. It can be observed that the surface of the self-supporting electrode is flat and smooth, meeting the basic requirements for electrode applications, proving the feasibility of preparing the self-supporting electrode with the assistance of anhydrous ethanol.

[0043] Figure 3 is a scanning electron microscope image of the self-supporting electrode prepared in Example 1 of the present invention. It can be seen from the picture that the filamentous binder wraps around solid substances such as active substances, proving that the binder can indeed be rolled to achieve in-situ fibrillation with the assistance of anhydrous ethanol.

[0044] Figure 4 are optical pictures of the composite electrodes with different areas of electrodeposited metallic nickel in the embodiments of the present invention. It can be proved from the pictures that electrodeposition can accurately achieve controllable current collector area.

[0045] Figure 5This is a schematic diagram of the cyclic voltammetry curve of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Example 1, the conventional nickel foam current collector electrode, and the composite electrode of electrodeposited metallic nickel in the embodiments of the present invention. Among them, the current density on the vertical axis is calculated based on the total mass of the positive and negative electrodes, including the masses of the respective positive and negative active materials and the current collector substrate; from Figure 5 It can be seen that the cyclic voltammetry curve of the symmetric supercapacitor assembled with the composite electrode is close to a rectangle, indicating that the electrode mainly exhibits capacitive behavior during the charge and discharge process, and reflects that the electrode material has good electrochemical reversibility and fast ion adsorption and desorption capabilities; the area enclosed by the curve is proportional to the electrode capacitance, and it can be concluded that the composite electrode based on binder fibrillation and electrodeposition is significantly superior to the conventional nickel foam current collector electrode under the same conditions, and slightly superior to the self-supporting electrode without electrodeposited current collector, thus proving the necessity of the existence of the current collector and the advantages of this electrode preparation method.

[0046] Figure 6 This is a comparative schematic diagram of the relationship between the specific capacitance and the current density of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Example 1, the conventional nickel foam current collector electrode, and the composite electrode of electrodeposited metallic nickel in the embodiments of the present invention. Among them, the current density on the horizontal axis and the specific capacitance on the vertical axis are calculated based on the total mass of the positive and negative electrodes, including the masses of the respective positive and negative active materials and the current collector substrate. From Figure 6 It can be seen that the composite electrode based on binder fibrillation and electrodeposition exhibits a specific capacitance of 40.7 F g -1 at a current density of 0.1 A g -1 based on the total mass of the positive and negative electrodes, and exhibits a specific capacitance of 21 F g -1 at a current density of 3 A g -1 , which is significantly superior to the conventional nickel foam current collector electrode under the same conditions, and slightly superior to the self-supporting electrode without electrodeposited current collector, thus proving the necessity of the existence of the current collector and the advantages of this electrode preparation method.

[0047] Figure 7 This is an electrochemical impedance schematic diagram of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Example 1 in the embodiments of the present invention. It is observed that the composite electrode based on binder fibrillation and electrodeposition has a small ohmic resistance and interfacial transfer impedance, corresponding to its excellent electrochemical performance.

[0048] Figure 8 This is a schematic diagram of the galvanostatic charge and discharge curves of an alkaline (6M KOH) symmetric supercapacitor assembled with the self-supporting electrode prepared in Example 1 at different current densities in the embodiments of the present invention. Compared with Figure 10In comparison, at the same current density, the charge-discharge time is slightly shortened, and the rate performance is slightly lower than that of the composite electrode based on binder fibrillation and electrodeposition, thus proving the necessity of the current collector and the advantages of this electrode preparation method.

[0049] Figure 9 It is a schematic diagram of the constant current charge-discharge curves of an alkaline (6M KOH) symmetric supercapacitor assembled with a conventional nickel foam current collector electrode at different current densities. Compared with Figure 10 In comparison, at the same current density, the charge-discharge time is significantly shortened, and the rate performance is significantly lower than that of the composite electrode based on binder fibrillation and electrodeposition. By this comparison, the advantages of the composite electrode preparation method are proved.

[0050] Figure 10 It is a schematic diagram of the constant current charge-discharge curves of an alkaline (6M KOH) symmetric supercapacitor assembled with the electrodeposited metal nickel composite electrode prepared in Example 1 in the embodiments of the present invention at different current densities. Under the condition of constant current charge-discharge, the change of voltage with time shows an obvious linear relationship, and the charge-discharge curves have an obvious triangular symmetry distribution, indicating that the reaction of this composite electrode is mainly the charge transfer on the electric double layer capacitor, and the electrode material has good electrochemical reversibility.

[0051] Example 2: The preparation method of the embodiment of the present invention includes the following process: Step 1: Weigh 850 mg of activated carbon, 50 mg of polytetrafluoroethylene, and 100 mg of acetylene black, add an appropriate amount of alcohol, ultrasonically disperse them in a petri dish, and dry them on a constant temperature heating table at 80 °C; then drop an appropriate amount of alcohol, use a scraper to gather the mixture on the petri dish into a whole, and roll the whole after uniform mixing into a ball through a rolling press with adjusted thickness to form an activated carbon self-supporting electrode with uniform thickness.

[0052] Step 2: Weigh 12 g of CuSO 4 ·6H 2 O, 2 g of H 3 BO 3 and 0.005 g of C 12 H 25 SO 4 Na, add them to 50 mL of deionized water, and fully dissolve them to prepare a uniform and transparent electrodeposition solution; connect the self-supporting electrode prepared above to the cathode of a DC power supply, connect a copper sheet to the anode, immerse them in the prepared electrodeposition solution, set the electrodeposition current to 50 mA·cm -1 , and the time to 5 min, then a composite electrode of an activated carbon self-supporting electrode and metallic copper can be obtained.

[0053] Example 3: The preparation method of the embodiment of the present invention includes the following process: Step 1: Weigh 850 mg of activated carbon, 50 mg of polytetrafluoroethylene, and 100 mg of acetylene black, add an appropriate amount of alcohol, ultrasonically disperse them in a petri dish, and dry them on a constant temperature heating table at 80 °C; then drop an appropriate amount of alcohol, use a scraper to gather the mixture on the petri dish into a whole, and roll and press the uniformly mixed and agglomerated whole through a roll press with adjusted thickness to form a self-supporting activated carbon electrode with uniform thickness.

[0054] Step 2: Weigh 12 g of Al 2 (SO 4 ) 3 ·6H 2 O, 2 g of H 3 BO 3 and 0.005 g of C 12 H 25 SO 4 Na, add them to 50 mL of deionized water, and fully dissolve to prepare a homogeneous and transparent electrodeposition solution; connect the self-supporting electrode prepared above to the cathode of a DC power supply, connect an aluminum sheet to the anode, immerse them in the prepared electrodeposition solution, set the electrodeposition current to 50 mA·cm -1 , and the time to 5 min to obtain a composite electrode of the self-supporting activated carbon electrode and metallic aluminum.

[0055] Example 4: The preparation method of the embodiment of the present invention includes the following process: Step 1: Weigh 800 mg of graphite, 100 mg of nanocellulose, and 100 mg of super p, add an appropriate amount of alcohol, ultrasonically disperse them in a petri dish, and dry them on a constant temperature heating table at 80 °C; then drop an appropriate amount of alcohol, use a scraper to gather the mixture on the petri dish into a whole, and roll and press the uniformly mixed and agglomerated whole through a roll press with adjusted thickness to form a self-supporting electrode with uniform thickness.

[0056] Step 2: Weigh 12 g of CuSO 4 ·6H 2 O, 2 g of H 3 BO 3 and 0.005 g of C 12 H 25 SO 4 Na, add them to 50 mL of deionized water, and fully dissolve to prepare a homogeneous and transparent electrodeposition solution; connect the self-supporting electrode prepared above to the cathode of a DC power supply, connect a copper sheet to the anode, immerse them in the prepared electrodeposition solution, set the electrodeposition current to 50 mA·cm -1 , and the time to 3 min to obtain a composite electrode of the self-supporting electrode and metallic copper.

[0057] Example 5: The preparation method of the embodiment of the present invention includes the following process: Step 1: Weigh 800 mg of graphite, 100 mg of nanocellulose, and 100 mg of super p, add an appropriate amount of alcohol, and ultrasonically disperse them in a petri dish. Dry them on a constant temperature heating table at 80 °C. Then, drop an appropriate amount of alcohol, and use a scraper to gather the mixture on the petri dish into a whole. Pass the uniformly mixed and agglomerated whole through a rolling press with adjusted thickness for rolling to form a self-supporting electrode with uniform thickness.

[0058] Step 2: Weigh 12 g of CuSO 4 ·6H 2 O, 2 g of H 3 BO 3 and 0.005 g of C 12 H 25 SO 4 Na, add them to 50 mL of deionized water, and fully dissolve to prepare a homogeneous and transparent electrodeposition solution. Connect the self-supporting electrode prepared above to the cathode of a DC power supply, connect a copper sheet to the anode, immerse them in the prepared electrodeposition solution, set the electrodeposition current to 50 mA·cm -1 , and the time to 5 min to obtain a composite electrode of the self-supporting electrode and metallic copper.

[0059] Example 6: The preparation method of the embodiment of the present invention includes the following process: Step 1: Weigh 800 mg of graphite, 100 mg of nanocellulose, and 100 mg of super p, add an appropriate amount of alcohol, and ultrasonically disperse them in a petri dish. Dry them on a constant temperature heating table at 80 °C. Then, drop an appropriate amount of alcohol, and use a scraper to gather the mixture on the petri dish into a whole. Pass the uniformly mixed and agglomerated whole through a rolling press with adjusted thickness for rolling to form a self-supporting electrode with uniform thickness.

[0060] Step 2: Weigh 12 g of CuSO 4 ·6H 2 O, 2 g of H 3 BO 3 and 0.005 g of C 12 H 25 SO 4 Na, add them to 50 mL of deionized water, and fully dissolve to prepare a homogeneous and transparent electrodeposition solution. Connect the self-supporting electrode to the cathode of a DC power supply, connect a copper sheet to the anode, immerse them in the prepared electrodeposition solution, set the electrodeposition current to 50 mA·cm -1 , and the time to 7 min to obtain a composite electrode of the self-supporting electrode and metallic copper.

[0061] Example 7: The preparation method of the embodiment of the present invention includes the following process: Step 1: Weigh 800 mg of the mixture of graphite and activated carbon, 100 mg of the mixture of ethylene-tetrafluoroethylene copolymer and polytetrafluoroethylene-ethylene copolymer, and 100 mg of super p, add an appropriate amount of alcohol, and ultrasonically disperse them in a petri dish. Then dry them on a constant temperature heating table at 80 °C. Then drop an appropriate amount of alcohol, and use a scraper to gather the mixture on the petri dish into a whole. Press the whole after uniform mixing and forming into a mass through a rolling press with adjusted thickness to form a self-supporting electrode with uniform thickness.

[0062] Step 2: Weigh 12 g of CuSO 4 ·6H 2 O, 2 g of H 3 BO 3 and 0.005 g of C 12 H 25 SO 4 Na, add them to 50 mL of deionized water, and fully dissolve to prepare a uniform and transparent electrodeposition solution. Connect the above self-supporting electrode to the cathode of a DC power supply, connect a copper sheet to the anode, immerse them in the prepared electrodeposition solution, set the electrodeposition current to 50 mA·cm -1 , and the time to 7 min to obtain a composite electrode of the self-supporting electrode and metallic copper.

[0063] In summary, the embodiment of the present invention provides a method for preparing a composite electrode based on binder fibrillation and electrodeposition, specifically related to an electrode preparation method based on binder fibrillation and electrodeposition to achieve controllable quality of the metal current collector, mainly including two parts: preparing a self-supporting electrode with filamentous binder winding and wrapping the active material by in-situ fibrillation of the binder and uniformly wrapping the active material and the conductive agent; growing a tightly combined and quality-area controllable metal current collector on the self-supporting electrode by electrochemical deposition according to requirements. The steps for preparing the self-supporting electrode in the embodiment of the present invention have a simple and easy-to-operate preparation process, high efficiency and low cost, and the electrode loading can be changed according to actual needs; the technical means of electrochemical deposition greatly solves the problem that the performance cannot be fully exerted due to insufficient binding force between the active material and the current collector, reduces the mass ratio of the current collector in the whole electrode, and improves the energy density of the device.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for preparing a composite electrode based on binder fibrillation and electrodeposition, characterized in that: The following steps are involved: The binder is in situ fibrillated and the active material and the conductive agent are uniformly wrapped to prepare a self-supporting electrode having the active material wrapped by the filamentous binder; wherein the thickness of the self-supporting electrode is controlled according to the load per unit area of ​​the active material; By adopting electrochemical deposition method, a tightly bonded metal current collector is grown on the prepared self-supporting electrode to prepare a composite electrode; wherein the current and time of electrochemical deposition are set according to the required mass proportion of the metal current collector in the composite electrode.

2. A method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 1, characterized in that: The step of in-situ fibrillating the binder and uniformly wrapping the active material and the conductive agent to prepare a self-supporting electrode having the active material wrapped by the filamentous binder comprises: Active materials, binders and conductive agents are selected according to requirements, and ultrasonically dispersed and dried at a constant temperature in a culture dish according to the required mass ratio; After drying, an appropriate amount of anhydrous ethanol is added to gather the mixture on the culture dish into a whole, and the uniformly mixed whole is rolled through a roller press to form a self-supporting electrode with a certain thickness and controllable load.

3. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 1, characterized in that: The active material is a mixture of one or more of a carbon-based material, a metal material and a conductive polymer material.

4. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 1, characterized in that: The binder is a mixture of one or more of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene-ethylene copolymer, polyacrylic acid, polyimide and modified cellulose.

5. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 1, characterized in that: The conductive agent is one of a carbon conductive agent, a metal conductive agent and a composite conductive agent, or a mixture of several of them.

6. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 1, characterized in that: The metal current collector is made of nickel, cobalt, aluminum or copper.

7. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 1, characterized in that: The steps of growing a tightly bonded metal current collector on the prepared self-supporting electrode by electrochemical deposition to prepare the composite electrode include: Prepare an electrodeposition solution; wherein the electrodeposition solution contains a deposition layer metal salt, a pH buffer and a surfactant; 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 a direct current power supply; The self-supporting electrode and the deposited layer metal sheet are placed in the prepared electrodeposition solution to carry out electrochemical deposition of the metal current collector to obtain a composite electrode with a metal current collector with a tightly bonded interface and controllable mass ratio.

8. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 7, characterized in that: The metal salt of the deposited layer is a mixture of one or more of sulfate, nitrate and chloride salts of the metal of the deposited layer.

9. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 7, characterized in that: The pH buffer is boric acid, formic acid, sodium citrate or sodium fluoroborate.

10. The method for preparing a composite electrode based on binder fibrillation and electrodeposition according to claim 7, characterized in that: The surfactant is a mixture of one or more of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and hexadecyltrimethylammonium bromide.

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