A method for preparing a dry electrode sheet

Abstract

The present application relates to the technical field of lithium battery, and specifically relates to a preparation method of dry-process pole piece. The method comprises the following steps: step 1: sputtering a layer of binder on a conductive mesh to obtain a conductive bonding mesh; step 2: mixing, rolling and pressing an active material, a conductive agent and a binder to obtain a dry-process self-supporting film; and step 3: simultaneously unwinding a current collector, the conductive bonding mesh and the dry-process self-supporting film, and roll-pressing the three to obtain a dry-process pole piece. The method can better increase the adhesion between the self-supporting film and the current collector, solve the problem of insufficient fibrillation of the adhesive and pole piece material loss during processing, increase the connection area of the conductive network of the dry-process pole piece, improve the conductivity, increase the adhesion of the dry-process pole piece, prolong the cycle life of the battery, and solve the problems of pole piece material loss and pole piece breakage under high curling rate.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically a method for preparing dry electrode sheets. Background Technology

[0002] With the continuous development and widespread application of lithium-ion battery technology, increasingly higher requirements are being placed on the performance and safety of lithium-ion batteries. As a crucial component within the battery, the electrode sheet's manufacturing method and quality directly affect the overall performance and lifespan of the battery.

[0003] In existing technologies, after dry powdering, the active layer is typically formed through a pre-pressing and secondary die-casting process, followed by direct lamination with the current collector to produce a dry-processed electrode. However, this process presents numerous challenges and problems. In dry processes, the fibrillation effect of the binder is crucial for constructing a self-supporting membrane. If the fibrillation effect of the binder is not fully realized, the electrode will be prone to shedding during subsequent processing, thus affecting the overall quality and performance of the electrode.

[0004] Furthermore, dry-process electrodes also face the challenge of insufficient compaction density during the compaction process. Insufficient compaction density leads to poor contact between particles, easily causing material loss and affecting the battery's charge / discharge performance and cycle life. More complexly, improper equipment operation during dry-process electrode fabrication can also trigger material loss. For example, improper handling during unloading, chopping, crushing, sieving, and sorting processes can lead to the loss of active material and damage to the electrode structure, resulting in material loss. Simultaneously, dry-process electrodes prepared using existing technologies exhibit poor electrical performance and are unsuitable for high-rate discharge and cycle life, which to some extent limits the application of dry-process electrodes in the field of high-performance lithium-ion batteries.

[0005] In summary, obtaining a dry electrode preparation method is of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing dry electrode sheets to solve the problems raised in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for preparing a dry electrode includes the following steps:

[0009] Step 1: Sputter a layer of adhesive onto the conductive mesh to obtain a conductive adhesive mesh;

[0010] Step 2: Mix the active material, conductive agent, and binder, and roll them to obtain a dry self-supporting membrane;

[0011] Step 3: Simultaneously unwind the current collector, conductive bonding mesh, and dry self-supporting film, and roll-press them together to obtain a dry electrode sheet.

[0012] In a more optimized manner, the dry electrode sheet structure comprises, from top to bottom, a dry self-supporting film, a conductive bonding mesh, a current collector, a conductive bonding mesh, and a dry self-supporting film; the thickness of the conductive mesh in the dry electrode sheet is 5~7µm, and the thickness of the layer formed by the adhesive is ≤1µm.

[0013] Ideally, the conductive mesh is made of at least one of metal, carbon material, or polymer material.

[0014] In a more optimized manner, the rolling of the dry self-supporting membrane includes two rolling processes: the first rolling pressure is 1 to 10 tons, and the thickness after rolling is 300 to 4000 μm; the second rolling pressure is 15 to 100 tons, and the thickness after rolling is 150 to 2000 μm.

[0015] Ideally, the pressure of the roller pressing composite is 25~40T.

[0016] In a more optimized manner, the raw materials of the dry self-supporting membrane include the following components: 94%~95% active material, 2%~3% conductive agent, and 3% binder by mass percentage.

[0017] In this application, the dry electrode is a dry positive electrode. Accordingly, the active material in the dry self-supporting membrane includes, but is not limited to, 911NCM, and the conductive agent includes, but is not limited to, conductive carbon black SP. The raw material of the binder includes one or two of polytetrafluoroethylene and polyvinylidene fluoride.

[0018] In the optimized scheme, the active material is 94-95% 911NCM, the conductive agent is 2-3% conductive carbon black SP, and the binder is 2% PTFE (polytetrafluoroethylene) and 1% PVDF (polyvinylidene fluoride).

[0019] Additionally, it should be noted that the methods for dry electrode sheets in this application are applicable to the preparation of dry negative electrode sheets; correspondingly, when used for dry negative electrode sheets, the optimal active material in the raw materials of the dry self-supporting membrane is SiC (C: 90%, Si: 10%).

[0020] In a further embodiment, the adhesive is further modified and optimized, specifically as follows: the preparation method of the adhesive is:

[0021] Step 1: Under a nitrogen atmosphere, polytetrafluoroethylene and sodium naphthalene activation solution are added to dimethylformamide and reacted at 20~30℃ for 3~10 minutes. After washing and filtration, pretreated polytetrafluoroethylene is obtained.

[0022] Step 2: Add pretreated polytetrafluoroethylene, acrylic acid, acrylamide, (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, hydroxyethyl acrylate, ammonium persulfate, and allyltrimethoxysilane to a deionized water-acetone mixed solvent, react at 50-70°C for 4-5 hours, then cool to 20-30°C and stir for 1-2 hours, wash and filter to obtain modified polytetrafluoroethylene;

[0023] Step 3: Mix modified polytetrafluoroethylene, oxalic acid, phenol and formaldehyde and react at 60~95℃ for 3~4 hours, cool down to 35~45℃, then dry at 80~130℃ for 1~2 hours, add 8~12wt% hexamethylenetetramine, pulverize and grind to obtain composite polytetrafluoroethylene powder.

[0024] Step 4: Mix the composite polytetrafluoroethylene powder, polyvinylidene fluoride, and carboxymethyl cellulose evenly to obtain the binder.

[0025] In a more optimized manner, the raw materials for the modified polytetrafluoroethylene, by mass parts, include 4-5 parts pretreated polytetrafluoroethylene, 4-5 parts acrylic acid, 2-3 parts acrylamide, 6-8 parts (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, 3-4 parts hydroxyethyl acrylate, 0.2-0.5 parts ammonium persulfate, 4-5 parts allyltrimethoxysilane, and 45-55 parts deionized water-acetone mixed solvent; wherein the mass ratio of deionized water to acetone in the raw materials of the deionized water-acetone mixed solvent is 2-2.5:1.

[0026] The raw materials for the composite polytetrafluoroethylene powder, by mass percentage, include 5-6 parts modified polytetrafluoroethylene, 0.2-0.4 parts oxalic acid, 4-5 parts phenol, 7-8 parts formaldehyde, and 0.5-1 parts 8-12 wt% hexamethylenetetramine.

[0027] In a more optimized manner, the mass ratio of composite polytetrafluoroethylene powder, polyvinylidene fluoride, and carboxymethyl cellulose in the raw materials of the adhesive is 1.7~2.3:1:1.

[0028] The process involves first activating polytetrafluoroethylene (PTFE), then grafting it with acrylic acid, acrylamide, (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, hydroxyethyl acrylate, and allyltrimethoxysilane under initiator conditions. Subsequently, the carboxyl and hydroxyl groups on the surface of the grafted modified PTFE undergo esterification to participate in the synthesis of phenolic resin, forming a three-dimensional network structure. This promotes fibrillation and improves the overall bonding performance, thermal stability, heat resistance, and mechanical properties of the binder. It can also more effectively guide the uniform distribution of active materials in the electrode, thereby solving the problem of material shedding during electrode processing, further reducing the internal resistance of the battery, and improving electrical performance and cycle stability.

[0029] In the previous method, fibrillation reduced the adhesion between the binder and the active material in the dry-process self-supporting membrane, leading to active material detachment and significantly increasing the battery's internal resistance, thus drastically reducing battery performance. In this new method, a binder is obtained by mixing composite polytetrafluoroethylene powder with polyvinylidene fluoride (PVDF) and carboxymethyl cellulose (CMC) at a smaller particle size. PVDF and CMC are non-fibrillated materials, which significantly improve the bonding force between the binder and the active material, thereby reducing active material detachment. The smaller particle size of the binder not only enhances adhesion but also promotes the uniform distribution of the active material in the electrode film. This uniform distribution not only improves the battery's energy density but also results in more stable and reliable performance during charge and discharge.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] (1) This scheme improves the self-generated cohesion and adhesion of dry electrode sheets.

[0032] (2) This scheme improves the curling rate and folding resistance of dry electrode sheets.

[0033] (3) This solution improves the battery’s electrical performance (internal resistance, rate capability, cycle life).

[0034] (4) This solution solves the process problems of strip breakage and material loss in dry electrode sheets.

[0035] (5) The scheme introduces a composite polytetrafluoroethylene powder binder to form a three-dimensional network structure, which enhances the fibrillation effect, thereby improving the overall bonding performance, thermal stability, heat resistance and mechanical properties of the binder. It solves the problem of material shedding, further reduces the battery internal resistance, and improves electrical performance and cycle stability. Furthermore, when mixed with non-fibrillated materials at a small particle size, it significantly improves the bonding force between the binder and the active material, and reduces the shedding of the active material. Attached Figure Description

[0036] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0037] Figure 1 This is a roadmap for a dry electrode preparation method. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] It should be noted that the following parts are by weight. There are no special restrictions on the purchasers of the raw materials involved in this invention. Exemplary examples include: sodium naphthalene activation solution purchased from Fangzhou (Fogang) Chemical Materials Co., Ltd.; acrylic acid purchased from Shandong Langcheng Chemical Co., Ltd.; and polytetrafluoroethylene purchased from Wuhan Haorong Biotechnology Co., Ltd.

[0040] In the following embodiments, the dry electrode sheet structure includes, from top to bottom, a dry self-supporting film, a conductive bonding mesh, a current collector, a conductive bonding mesh, and a dry self-supporting film.

[0041] Example 1: A method for preparing a dry electrode sheet, comprising the following steps:

[0042] Step 1: Sputter a layer of adhesive onto a conductive mesh to obtain a conductive adhesive mesh; wherein the material of the conductive mesh is aluminum, the thickness of the conductive mesh is 5µm, and the thickness of the adhesive layer is 1µm;

[0043] Step 2: Mix 94% active material (911NCM), 3% conductive agent (conductive carbon black SP), and 3% binder by weight percentage; perform the first rolling at a rolling pressure of 5.5 tons, the thickness after the first rolling is 1900 μm, and then perform the second rolling at a rolling pressure of 57.5 tons, the thickness after the second rolling is 1075 μm, to obtain a dry self-supporting membrane;

[0044] Step 3: Unwind the current collector, conductive bonding mesh, and dry self-supporting film simultaneously, and roll-press them together under a pressure of 33T to obtain the dry positive electrode sheet;

[0045] In this embodiment, the adhesive used in steps 1 and 2 is 2% PTFE and 1% PVDF.

[0046] Example 2: A method for preparing a dry electrode sheet, comprising the following steps:

[0047] Step 1: Sputter a layer of adhesive onto a conductive mesh to obtain a conductive adhesive mesh; wherein the material of the conductive mesh is aluminum, the thickness of the conductive mesh is 5µm, and the thickness of the adhesive layer is 1µm;

[0048] Step 2: Mix 94% active material (911NCM), 3% conductive agent (conductive carbon black SP), and 3% binder by weight percentage; perform the first rolling at a rolling pressure of 5.5 tons, the thickness after the first rolling is 1900 μm, and then perform the second rolling at a rolling pressure of 57.5 tons, the thickness after the second rolling is 1075 μm, to obtain a dry self-supporting membrane;

[0049] Step 3: Unwind the current collector, conductive bonding mesh, and dry self-supporting film simultaneously, and roll-press them together under a pressure of 33T to obtain the dry positive electrode sheet;

[0050] In this embodiment, the preparation method of the adhesive in steps 1 and 2 is as follows: (1) Under a nitrogen atmosphere, polytetrafluoroethylene and sodium naphthalene activation solution are added to dimethylformamide and reacted at 25°C for 7 minutes. After washing and filtration, pretreated polytetrafluoroethylene is obtained; (2) 4.5 parts of pretreated polytetrafluoroethylene, 4.5 parts of acrylic acid, 2.5 parts of acrylamide, 7 parts of (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, 3.5 parts of hydroxyethyl acrylate, 0.3 parts of ammonium persulfate, and 4.5 parts of allyltrimethoxysilane are added to 50 parts of deionized water-acetone mixed solvent and reacted at 60°C. (2) React at ℃ for 4.5 hours, then cool down to 25℃ and stir for 1.5 hours, wash and filter to obtain modified polytetrafluoroethylene; (3) Mix 5.5 parts of modified polytetrafluoroethylene, 0.3 parts of oxalic acid, 4.5 parts of phenol and 7.5 parts of formaldehyde at 80℃ for 3.5 hours, cool down to 40℃, then dry at 100℃ for 1.5 hours, add 0.8 parts of 10wt% hexamethylenetetramine, pulverize and grind to obtain composite polytetrafluoroethylene powder; (4) Mix composite polytetrafluoroethylene powder, polyvinylidene fluoride and carboxymethyl cellulose in a mass ratio of 2:1:1 evenly to obtain binder.

[0051] Comparative Example 1: Dry electrode fabrication using existing technology, specifically:

[0052] Step 1: Mix 94% active material (911NCM), 3% conductive agent (conductive carbon black SP), and 3% binder by weight percentage; the binder is the same as that in Example 2; to obtain the raw material mixture;

[0053] Step 2: The raw material mixture is pre-compressed once at a pressure of 5.5 tons to obtain a pre-formed active layer with a thickness of 1900μm;

[0054] Step 3: The pre-formed active layer is die-cast a second time at a pressure of 57.5 tons to obtain the active layer with a thickness of 1075μm.

[0055] Step 4: Thermally combine the active layer with the current collector to obtain a dry positive electrode sheet.

[0056] Comparative Example 2: Dry electrode preparation using polytetrafluoroethylene as a binder, specifically:

[0057] Step 1: Mix 94% active material (911NCM), 3% conductive agent (conductive carbon black SP), and 3% binder by weight percentage; the binder is a single polytetrafluoroethylene; to obtain the raw material mixture;

[0058] Step 2: The raw material mixture is pre-compressed once at a pressure of 5.5 tons to obtain a pre-formed active layer with a thickness of 1900μm;

[0059] Step 3: The pre-formed active layer is die-cast a second time at a pressure of 57.5 tons to obtain the active layer with a thickness of 1075μm.

[0060] Step 4: Thermally combine the active layer with the current collector to obtain a dry positive electrode sheet.

[0061] Comparative Example 3: Based on Example 2, composite polytetrafluoroethylene powder was used as the binder, and the rest of the process remained unchanged, except that:

[0062] In this embodiment, the preparation method of the adhesive in steps 1 and 2 is as follows: (1) Under a nitrogen atmosphere, polytetrafluoroethylene and sodium naphthalene activation solution are added to dimethylformamide and reacted at 25°C for 7 minutes. After washing and filtration, pretreated polytetrafluoroethylene is obtained; (2) 4.5 parts of pretreated polytetrafluoroethylene, 4.5 parts of acrylic acid, 2.5 parts of acrylamide, 7 parts of (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, 3.5 parts of hydroxyethyl acrylate, 0.3 parts of ammonium persulfate, and 4.5 parts of allyl triacrylate are added to dimethylformamide. Methoxysilane was added to 50 parts of deionized water-acetone mixed solvent and reacted at 60°C for 4.5 hours. Then the temperature was lowered to 25°C and stirred for 1.5 hours. After washing and filtration, modified polytetrafluoroethylene was obtained. (3) 5.5 parts of modified polytetrafluoroethylene, 0.3 parts of oxalic acid, 4.5 parts of phenol and 7.5 parts of formaldehyde were mixed and reacted at 80°C for 3.5 hours. The temperature was lowered to 40°C and then dried at 100°C for 1.5 hours. 0.8 parts of 10wt% hexamethylenetetramine were added, pulverized and ground to obtain the binder.

[0063] Comparative Example 4: Based on Example 2, modified polytetrafluoroethylene was used instead of composite polytetrafluoroethylene powder, with the rest of the process remaining unchanged. The difference is as follows:

[0064] In this embodiment, the preparation method of the adhesive in steps 1 and 2 is as follows: (1) Under a nitrogen atmosphere, polytetrafluoroethylene and sodium naphthalene activation solution are added to dimethylformamide and reacted at 25°C for 7 minutes. After washing and filtration, pretreated polytetrafluoroethylene is obtained; (2) 4.5 parts of pretreated polytetrafluoroethylene, 4.5 parts of acrylic acid, 2.5 parts of acrylamide, 7 parts of (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, 3.5 parts of hydroxyethyl acrylate, 0.3 parts of ammonium persulfate, and 4.5 parts of allyltrimethoxysilane are added to 50 parts of deionized water-acetone mixed solvent and reacted at 60°C for 4.5 hours. Then, the temperature is lowered to 25°C and stirred for 1.5 hours. After washing and filtration, modified polytetrafluoroethylene is obtained; (3) Modified polytetrafluoroethylene, polyvinylidene fluoride, and carboxymethyl cellulose in a mass ratio of 2:1:1 are mixed evenly to obtain the adhesive.

[0065] Comparative Example 5, based on Example 2, without the addition of (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, with the remaining processes unchanged, the difference being:

[0066] In this embodiment, the preparation method of the adhesive in steps 1 and 2 is as follows: (1) Under a nitrogen atmosphere, polytetrafluoroethylene and sodium naphthalene activation solution are added to dimethylformamide and reacted at 25°C for 7 minutes. After washing and filtration, pretreated polytetrafluoroethylene is obtained; (2) 5 parts of pretreated polytetrafluoroethylene, 4.5 parts of acrylic acid, 2.5 parts of acrylamide, 3.5 parts of hydroxyethyl acrylate, 0.3 parts of ammonium persulfate, and 4.5 parts of allyltrimethoxysilane are added to 50 parts of deionized water-acetone mixed solvent and reacted at 60°C for 4.5 hours, and then cooled to Stirred at 25°C for 1.5 hours, washed and filtered to obtain modified polytetrafluoroethylene; (3) Mix 5.5 parts of modified polytetrafluoroethylene, 0.3 parts of oxalic acid, 4.5 parts of phenol and 7.5 parts of formaldehyde at 80°C for 3.5 hours, cool down to 40°C, and then dry at 100°C for 1.5 hours. Add 0.8 parts of 10wt% hexamethylenetetramine, crush and grind to obtain composite polytetrafluoroethylene powder; (4) Mix composite polytetrafluoroethylene powder, polyvinylidene fluoride and carboxymethyl cellulose in a mass ratio of 2:1:1 evenly to obtain adhesive.

[0067] Testing Experiment: The dry-process positive electrode sheets prepared in Examples 1-4 and Comparative Examples 1-5 were subjected to performance testing; wherein, 1. the dry-process positive electrode sheets were cut into qualified stacked sheets using a die-cutting device (dimensions: coating area length 200mm, width 150mm, tab length 25mm, width 50mm on the basis of the electrode sheet); 2. the negative electrode sheet was 5mm larger (width 155mm film surface); 3. after the stacking process, hot pressing and cold pressing were performed to obtain the cell (with tabs at both ends), and then it was made into a soft pack battery, and the electrical performance was tested. The test results are shown in Table 1.

[0068]

[0069] Results Analysis: According to the data analysis in Table 1, the dry electrode sheet prepared by this method can better increase the adhesion between the self-supporting film and the fluid; it can solve the problem of insufficient fibrillation effect of the binder and the problem of electrode shedding during processing; it can increase the connection area of ​​the conductive network of the dry electrode sheet, resulting in better conductivity; it can increase the adhesion of the dry electrode sheet, resulting in a longer battery cycle life; and it can solve the problems of electrode shedding and electrode breakage under high curling rate.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a dry electrode, characterized in that: Includes the following steps: Step 1: Sputter a layer of adhesive onto the conductive mesh to obtain a conductive adhesive mesh; Step 2: Mix the active material, conductive agent, and binder, and roll them to obtain a dry self-supporting membrane; Step 3: Simultaneously unwind the current collector, conductive bonding mesh, and dry self-supporting film, and roll-press them together to obtain a dry electrode sheet; The adhesive is prepared by: Step 1: Under a nitrogen atmosphere, polytetrafluoroethylene and sodium naphthalene activation solution are added to dimethylformamide and reacted at 20~30℃ for 3~10 minutes. After washing and filtration, pretreated polytetrafluoroethylene is obtained. Step 2: Add pretreated polytetrafluoroethylene, acrylic acid, acrylamide, (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, hydroxyethyl acrylate, ammonium persulfate, and allyltrimethoxysilane to a deionized water-acetone mixed solvent, react at 50-70°C for 4-5 hours, then cool to 20-30°C and stir for 1-2 hours, wash and filter to obtain modified polytetrafluoroethylene; Step 3: Mix modified polytetrafluoroethylene, oxalic acid, phenol and formaldehyde and react at 60~95℃ for 3~4 hours, cool down to 35~45℃, then dry at 80~130℃ for 1~2 hours, add 8~12wt% hexamethylenetetramine, pulverize and grind to obtain composite polytetrafluoroethylene powder. Step 4: Mix the composite polytetrafluoroethylene powder, polyvinylidene fluoride, and carboxymethyl cellulose evenly to obtain the binder.

2. The method for preparing a dry electrode sheet according to claim 1, characterized in that: The dry electrode sheet has a structure from top to bottom including a dry self-supporting film, a conductive bonding mesh, a current collector, a conductive bonding mesh, and a dry self-supporting film; the thickness of the conductive mesh in the dry electrode sheet is 5~7µm, and the thickness of the layer formed by the adhesive is ≤1µm.

3. The method for preparing a dry electrode sheet according to claim 1, characterized in that: The conductive mesh is made of at least one of the following materials: metal, carbon material, and polymer material.

4. The method for preparing a dry electrode sheet according to claim 1, characterized in that: The dry self-supporting membrane is rolled in two stages. The first rolling pressure is 1 to 10 tons, and the thickness after rolling is 300 to 4000 μm. The second rolling pressure is 15 to 100 tons, and the thickness after rolling is 150 to 2000 μm.

5. The method for preparing a dry electrode sheet according to claim 1, characterized in that: The pressure of the roller pressing composite is 25~40T.

6. The method for preparing a dry electrode sheet according to claim 1, characterized in that: The raw materials of the dry self-supporting membrane include the following components: 94%~95% active material, 2%~3% conductive agent, and 3% binder by mass percentage.

7. The method for preparing a dry electrode sheet according to claim 1, characterized in that: The raw materials for the adhesive include one or two of polytetrafluoroethylene and polyvinylidene fluoride.

8. The method for preparing a dry electrode sheet according to claim 1, characterized in that: The modified polytetrafluoroethylene raw materials, by mass parts, consist of 4-5 parts pretreated polytetrafluoroethylene, 4-5 parts acrylic acid, 2-3 parts acrylamide, 6-8 parts (2E)-3-(6-amino-3-pyridyl)-2-acrylic acid, 3-4 parts hydroxyethyl acrylate, 0.2-0.5 parts ammonium persulfate, 4-5 parts allyltrimethoxysilane, and 45-55 parts deionized water-acetone mixed solvent; the mass ratio of deionized water to acetone in the deionized water-acetone mixed solvent is 2-2.5:

1. The raw materials for the composite polytetrafluoroethylene powder, by mass percentage, include 5-6 parts modified polytetrafluoroethylene, 0.2-0.4 parts oxalic acid, 4-5 parts phenol, 7-8 parts formaldehyde, and 0.5-1 parts 8-12 wt% hexamethylenetetramine.

9. The method for preparing a dry electrode sheet according to claim 1, characterized in that: In the raw materials of the adhesive, the mass ratio of composite polytetrafluoroethylene powder, polyvinylidene fluoride, and carboxymethyl cellulose is 1.7~2.3:1:1.

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