Preparation of polymer conductive binder and application of polymer conductive binder in lithium ion battery

Abstract

The invention discloses preparation of a polymer conductive binder and application of the polymer conductive binder in a lithium ion battery, and belongs to the field of lithium ion batteries. A main chain of the high-molecular conductive binder is of a conjugated structure, and a side chain or the main chain contains functional groups such as lithium phenolate, lithium carboxylate, furanone and lactone; the preparation method comprises the following steps: carrying out heat treatment on a specific polymeric monomer and an initiator in an inert atmosphere and a solvent in the presence of a lithium source, and carrying out post-treatment to obtain a target product. The polymer conductive binder can effectively fill pores of active substances, buffer volume expansion and prevent the active substances from falling off. The polymer conductive binder has higher intrinsic conductivity (greater than or equal to 102S / cm), stronger electrode bonding strength (greater than or equal to 1.5 N / cm) and considerable lithium ion storage capacity (specific capacity greater than or equal to 200mAh / g), can remarkably improve the capacity and cycling stability of the battery, and has a wide market application prospect.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery materials, specifically relating to the preparation of a polymer conductive binder and its application in lithium-ion batteries. Background Technology

[0002] With the continuous development of society, environmental pollution and global warming have become increasingly prominent issues. Against this backdrop, optimizing the energy structure and increasing the proportion of non-fossil energy use have become research hotspots, and establishing large-scale, efficient electrochemical energy storage systems is one of the keys to fully utilizing renewable energy. Therefore, developing low-cost, green, environmentally friendly, safe, and reliable electrochemical energy storage technologies has become an important research goal in the energy field. With the widespread adoption of portable electronic products, the extensive use of electric vehicles, and the rapid development of smart grids, the application of lithium-ion batteries is becoming increasingly widespread, driving the accelerated adjustment of the energy structure. Developing rechargeable batteries with higher energy density, greater environmental friendliness, longer cycle life, and greater safety has become a primary issue that urgently needs to be addressed in the current energy storage research field, bearing the important responsibility of promoting energy transformation and contributing to sustainable development.

[0003] In the complex system of lithium-ion batteries, the binder, as an indispensable part of the electrode material, although its proportion is small, is crucial. It tightly connects the electrode active material and conductive agent and firmly adheres them to the current collector, preventing the active material from falling off during charging and discharging and maintaining the integrity of the electrode. A good binder can uniformly disperse the active material and conductive agent, build an effective electron and ion transport network, reduce electrode impedance, promote electron conduction in the electrode material and lithium ion migration between the electrode and the electrolyte, thereby improving the battery's charge and discharge efficiency and rate performance. During charging and discharging, especially when using high-specific-capacity positive and negative electrode active materials (such as silicon-based negative electrodes), the electrode material undergoes significant volume changes. The binder, with its flexibility and elasticity, can buffer the stress generated by these volume changes, reduce electrode material pulverization and detachment, extend the battery's cycle life, and thus maintain the battery's electrochemical activity. At the same time, the binder can enhance the mechanical strength of the electrode, enabling it to withstand the processing during battery manufacturing and the external forces such as vibration and compression in actual use, ensuring the battery's reliability and safety.

[0004] Initially, polyvinylidene fluoride (PVDF) was the first commercially available binder for lithium-ion batteries due to its excellent chemical stability, high mechanical strength, and wide electrochemical stability window. However, with the continuous expansion of lithium-ion battery applications, the performance requirements for binders have become increasingly stringent. Traditional binders have gradually revealed some shortcomings, such as environmentally unfriendly preparation processes, insufficient bonding performance with certain novel electrode materials, and inability to meet the buffering requirements of volume changes during charge and discharge for high-capacity electrode materials. To overcome the limitations of traditional binders, researchers began developing new types. Water-based binders emerged, such as sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polyacrylic acid (PAA). Water-based binders use water as a solvent, offering advantages such as environmental friendliness and low cost, and exhibiting superior properties compared to PVDF binders in certain aspects. For example, CMC can form hydrogen bonds with the hydroxyl groups on the surface of silicon-based anode materials, enhancing the bonding effect and improving the cycle stability of silicon-based anodes; SBR has good flexibility, effectively buffering the volume changes of electrode materials.

[0005] In recent years, with the increasing demands on lithium-ion battery performance, such as higher energy density, longer cycle life, and better rate performance, novel lithium-ion battery structures have emerged, posing even more stringent challenges to binder performance. This has prompted researchers to develop binders with special functions, such as conductive binders, self-healing binders, and smart responsive binders, to meet the performance requirements of lithium-ion batteries in different application scenarios. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this invention provides a method for preparing a polymeric conductive binder and its application in lithium-ion batteries. This binder also possesses lithium-ion battery activity, effectively improving the specific capacity of the positive electrode.

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

[0008] This invention relates to a polymeric conductive adhesive, the main chain of which is a polymeric carbon chain conjugated with phenol and acetylene, containing functional groups of phenolic and carboxylate negatively charged groups, and may also contain furanone groups. The paired cation X is at least one of hydrogen, lithium, sodium, potassium, and ammonium salts. Its structural diagram is shown below:

[0009] .

[0010] The conductivity of the polymer conductive adhesive is ≥10 S / cm.

[0011] Furthermore, the structure of the polymer conductive adhesive is preferably as follows:

[0012] or .

[0013] The value of n ranges from 300 to 3000.

[0014] That is, its main chain is a polyphenolic acetylenic carbon chain, containing functional groups of lithium phenolate and lithium carboxylate, and it is also allowed to contain furanone groups and protons, and has the performance of an organic cathode lithium-ion battery.

[0015] The preparation method of the polymer conductive adhesive of the present invention includes the following steps:

[0016] Step 1: Mix monomer A and initiator B in a certain proportion in the reactor, and add solvent to dissolve them;

[0017] Step 2: Under an inert atmosphere, add a cyclizing agent to the system from Step 1 and carry out a heat treatment reaction under controlled conditions;

[0018] Step 3: Wash, purify and dry the reaction product, or disperse it in a liquid.

[0019] The polymer monomer A is at least one of benzodione difuran and 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid), and its structure is shown below:

[0020]

[0021] The initiator B is tetramethyl-1,4-benzoquinone. The molar ratio of the polymer monomer A to the initiator B is 1:0.1~20.

[0022] The cyclizing agent is at least one selected from carbonates, hydroxides, ammonia, and organometallic compounds, with the metal component being at least one selected from lithium, sodium, and potassium. The molar ratio of the polymer monomer A to the cyclizing agent is 1:1.5~20.

[0023] Furthermore, the cyclizing agent is preferably a lithium-ionizing agent. The lithium-ionizing agent includes at least one or more of lithium hydroxide, lithium carbonate, lithium methoxide, lithium tert-butoxide, lithium hydride, or diisopropylaminolithium.

[0024] The inert atmosphere is at least one of nitrogen, argon, and helium.

[0025] The solvent is one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, acetonitrile, and methanol.

[0026] The heating rate of the heat treatment is 2~10℃ / min, the temperature is 20~200℃, and the time is 0.1~72h.

[0027] The present invention provides a polymeric conductive adhesive prepared by the aforementioned preparation method.

[0028] The polymeric conductive adhesive possesses at least two of the following properties:

[0029] 1) Lithium-ion cathode, discharge voltage 3.6V-1.6V, specific capacity approximately 200 mAh / g;

[0030] 2) Conductivity ≥ 10 2 S / cm;

[0031] 3) The bonding strength with the current collector (such as aluminum foil) is ≥1.5 N / cm.

[0032] The present invention also provides the application of the aforementioned polymeric conductive binder in lithium-ion batteries.

[0033] When this binder is used in lithium-ion batteries, the binder, active material, conductive agent, and solvent are mixed to obtain a positive electrode slurry. The positive electrode material is then coated onto a positive electrode foil material and dried to obtain the lithium-ion battery positive electrode material. The drying temperature is between 80-150℃.

[0034] The active material comprises lithium-rich manganese-based cathode material, lithium iron phosphate, or NCM811; the conductive agent comprises Ketjen black, Super P, carbon nanotubes, or acetylene black; the solvent comprises at least one of N-methylpyrrolidone, water, ethanol, and isopropanol; the mass ratio of active material, conductive agent, and binder is 6~9:0~4:1.

[0035] This invention synthesizes a lithium-ion battery-active binder via a hydrothermal method. In this process, the monomer benzodione difuran reacts with the initiator tetramethyl-1,4-benzoquinone to form a polymer with C=O. Under the influence of lithium salt and high temperature, free hydrogen ions (H+) in the polymer... + Lithium ions (Li) are generated. + In the substitution reaction, the furan ring undergoes ring-opening (or -COOH and -OH dehydrate to form a lactone ring), and connects with -OH and -OLi. The final product contains both -OH (strongly polar, easily forms hydrogen bonds, improving the hydrophilicity or adhesion of the material) and -OLi (provides Li⁺ sites, enhancing ion transport capability); or in the polymer monomer 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid), adjacent -COOH and -OH (due to the fused ring structure, the spatial distance is relatively close) can dehydrate to form a lactone ring. Different molecules of -COOH and -OH (including phenolic hydroxyl groups) can dehydrate to form ester bonds (-COO-). Through multiple intermolecular reactions, the polymer backbone is gradually formed. At the same time, under the action of lithium salt and high temperature, the free hydrogen ions (H⁺) in the polymer... + Lithium ions (Li) are generated. +The substitution reaction forms a polymer backbone with a salt-type structure containing -OLi and -COOLi, an lactone ring, and ester bonds. This reaction allows for the control of the polymer's ionic conductivity, mechanical strength, and chemical stability. The polymer can be used to form films independently, exhibiting excellent flexibility and adhesion. Its fibrous morphology allows it to fill the pores of active materials, effectively preventing the active material from detaching due to volume expansion. It also demonstrates good adhesion to active materials, conductive agents, and current collectors.

[0036] The polymer binder prepared by this invention has good conductivity, and not only introduces lithium ions (Li... + It also provides the structural characteristics of the organic active group C=O, increasing the number of lithium ions (Li) during charging and discharging. + It can insert and extract active sites, thereby improving the capacity of lithium-ion batteries and increasing the specific capacity of lithium-rich manganese oxide cathodes. It can also serve as a polymeric binder with both conductivity and adhesion properties, providing a reliable technical path for the practical application of high-energy-density lithium-ion batteries.

[0037] The binder obtained by this invention belongs to a carbonyl polymer. Its highly conjugated molecular structure and doping effect significantly improve the intrinsic conductivity of the material, effectively solving the common problems of high solubility and poor conductivity of traditional organic molecules in electrolytes. Based on its role as a polymeric binder with both conductivity and adhesion properties and lithium-ion battery cathode activity, this lays the foundation for the preparation of batteries with higher energy / power density.

[0038] The polymer obtained by this invention is uniformly dispersed in a solvent into a black solution. By replacing the solvent, it can be directly prepared into a binder slurry. Then, active materials and conductive agents can be directly added to prepare a positive electrode slurry. Finally, it can be prepared into a positive electrode material through coating, drying and rolling processes.

[0039] In summary, this invention, through innovative molecular structure design and preparation process, has produced a novel polymer binder with higher conductivity, better thermal stability, stronger peel strength, and lithium battery cathode activity, providing important technical support for the development of high-performance, low-cost new energy storage devices. Attached Figure Description

[0040] Figure 1 The image shows the XRD pattern of the lithium battery cathode binder prepared in Example 1.

[0041] Figure 2 This is a TEM image of the lithium battery positive electrode binder prepared in Example 1.

[0042] Figure 3 The image shows the Raman diagram of the lithium-ion battery cathode binder prepared in Example 1.

[0043] Figure 4 The figure shows the solubility of the lithium battery positive electrode binder prepared in Example 1 in different solvents. Figure (b) shows the state of the sample in Figure (a) after 48 hours. The solvents are 1-propylene carbonate, 2-water, 3-dimethyl sulfoxide, 4-tetrahydrofuran, 5-N'N-dimethylformamide, and 6-diethylene glycol dimethyl ether.

[0044] Figure 5 This is a comparison of the conductivity of the lithium battery cathode binder prepared in Example 1 with that of common commercially available binders.

[0045] Figure 6 The figures show the contact angles between the lithium-ion battery cathode binder and PVDF prepared in Example 1 and H2O and LiPF6 DMC-EC. Figures a and b show the contact angles between the binder and H2O and LiPF6 DMC-EC; figures c and d show the contact angles between PVDF and H2O and LiPF6 DMC-EC.

[0046] Figure 7 This demonstrates the flexibility properties of the lithium-ion battery cathode binder prepared in Example 1.

[0047] Figure 8 The charge-discharge curves of the lithium battery positive electrode binder prepared in Example 8 are shown for direct application to the lithium battery positive electrode.

[0048] Figure 9 The peel strength of the lithium battery positive electrode binder prepared in Example 8 is used in lithium batteries.

[0049] Figure 10 The graph shows the cycle performance of the lithium-ion battery positive electrode binder prepared in Example 8 when applied to a lithium-ion battery.

[0050] Figure 11 Impedance diagram of the lithium battery positive electrode binder prepared in Example 8 applied to a lithium-ion battery.

[0051] Figure 12 This is a comparison chart showing the specific capacity of the lithium-ion battery cathode binder prepared in Example 8 applied to lithium-rich manganese-based cathode materials. Detailed Implementation

[0052] The purpose of this invention is to provide a method for preparing a lithium-ion battery-active binder:

[0053] 1. Mix 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) with a lithiation reagent and stir at room temperature to generate a lithiation product. Mix the obtained lithiation product with tetramethyl-1,4-benzoquinone to obtain a mixed material. Dissolve the mixed material in a solvent to obtain a solution.

[0054] 2. Mix benzodione difuran, tetramethyl-1,4-benzoquinone and lithium reagent to obtain a mixed material, and dissolve the mixed material in a solvent to obtain a solution.

[0055] The solution was heat-treated under a protective atmosphere to obtain the lithium battery positive electrode binder.

[0056] In this invention, the molar ratio of benzodione difuran, 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) and tetramethyl-1,4-benzoquinone is 1:0.1~20, more preferably 1:1~2.

[0057] In this invention, the lithiumizing agent includes at least one or more of lithium hydroxide, lithium carbonate, lithium tert-butoxide (lithium methoxide), lithium hydride, or diisopropylaminolithium; the molar ratio of benzo[a]dione difuran, 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) to the lithiumizing agent is 1:1.5~20, more preferably 1:1.5~4. The solvent includes one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, and acetonitrile. The amount of solvent used is not specifically limited and can be adjusted according to actual conditions.

[0058] In this invention, the protective atmosphere includes at least one of nitrogen, argon, and helium; the heating rate of the heat treatment is 2~10℃ / min, the temperature is 20~200℃, and the time is 0.1~72h.

[0059] This invention provides a lithium-ion battery-active binder prepared by the aforementioned method.

[0060] The present invention also provides the application of the lithium-ion battery-active binder in lithium-ion batteries.

[0061] In this invention, when a lithium-ion battery active binder is used in a lithium-ion battery, it is preferable to mix the binder, active material, conductive agent and solvent to obtain a positive electrode slurry, and then coat the positive electrode slurry onto a positive electrode foil to obtain a positive electrode material for an ion battery.

[0062] The active material preferably includes lithium-rich manganese-based cathode material, lithium iron phosphate, and NCM811; the conductive agent preferably includes Ketjen Black, Super P, carbon nanotubes, and acetylene black; the solvent preferably includes at least one selected from N-methylpyrrolidone, water, ethanol, and isopropanol. The preferred ratio of conductive agent, active material, and binder is 0~4:6~9:1, more preferably 0~2:7~9:1; the amount of solvent is not particularly limited and can be adjusted according to actual conditions, and the preferred ratio of binder to solvent is 100mg:400μL.

[0063] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0064] Example 1:

[0065] Under a nitrogen atmosphere, benzodione difuran was dissolved in dimethyl sulfoxide at a concentration of 30 mg / mL to obtain a clear and transparent solution. Tetramethyl-1,4-benzoquinone was added, with a molar ratio of tetramethyl-1,4-benzoquinone to benzodione difuran of 1:1. Lithium carbonate was added as a lithiation agent, with a molar ratio of lithium carbonate to benzodione difuran of 1:1.5. The mixture was then reacted in an oven at 100°C for 1 hour to obtain a blue-green solution, which is the lithium-ion battery positive electrode binder.

[0066] Example 2:

[0067] Under a nitrogen atmosphere, benzodione difuran was dissolved in N,N-dimethylformamide at a concentration of 30 mg / mL to obtain a clear and transparent solution. Tetramethyl-1,4-benzoquinone was added, with a molar ratio of tetramethyl-1,4-benzoquinone to benzodione difuran of 1:1.5. Lithium carbonate was added as a lithiation agent, with a molar ratio of lithium carbonate to benzodione difuran of 1:1.5. The mixture was then reacted in an oven at 100°C for 1 hour to obtain a blue-green solution, which is the lithium-ion battery positive electrode binder.

[0068] Example 3:

[0069] Under a nitrogen atmosphere, benzodione difuran was dissolved in N-methylpyrrolidone at a concentration of 15 mg / mL to obtain a clear, transparent solution. Tetramethyl-1,4-benzoquinone was added, with a molar ratio of tetramethyl-1,4-benzoquinone to benzodione difuran of 1:1. Lithium carbonate was added as a lithiation agent, with a molar ratio of lithium carbonate to benzodione difuran of 1:1.5. The mixture was then reacted in an oven at 100°C for 1 hour to obtain a blue-green solution, which is the lithium-ion battery positive electrode binder.

[0070] Example 4:

[0071] Benzodicarbonamide was dissolved in N,N-dimethylacetamide at a concentration of 15 mg / mL under an argon atmosphere to obtain a clear and transparent solution. Tetramethyl-1,4-benzoquinone was added, with a molar ratio of tetramethyl-1,4-benzoquinone to benzodicarbonamide of 1:1.5. Lithium carbonate was added as a lithiation agent, with a molar ratio of lithium carbonate to benzodicarbonamide of 1:2. The mixture was then reacted in an oven at 100°C for 1 hour to obtain a blue-green solution, which is the lithium-ion battery positive electrode binder.

[0072] Example 5:

[0073] Benzodicarbonamide was dissolved in dimethyl sulfoxide at a concentration of 30 mg / mL under an argon atmosphere to obtain a clear and transparent solution. Tetramethyl-1,4-benzoquinone was added, with a molar ratio of tetramethyl-1,4-benzoquinone to benzodicarbonamide of 1:1.5. Lithium hydroxide was added as a lithiation agent, with a molar ratio of lithium hydroxide to benzodicarbonamide of 1:2. The mixture was then placed in an oven at 120°C for 1 hour to obtain a blue-green solution, which is the lithium-ion battery positive electrode binder.

[0074] Example 6:

[0075] Benzodicarbonamide was dissolved in dimethyl sulfoxide at a concentration of 30 mg / mL under an argon atmosphere to obtain a clear and transparent solution. Tetramethyl-1,4-benzoquinone was added, with a molar ratio of tetramethyl-1,4-benzoquinone to benzodicarbonamide of 1:1.5. Lithium methoxide was added as a lithiation agent, with a molar ratio of lithium methoxide to benzodicarbonamide of 1:2. The mixture was reacted in an oven at 100°C for 2 hours to obtain a blue-green solution, which is the lithium-ion battery positive electrode binder.

[0076] Example 7:

[0077] Lithium hydroxide was used as the lithiation reagent and mixed with 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) in methanol, wherein the molar ratio of 2,5-dihydroxyterephthalic acid to lithium hydroxide was 1:1.5. The mixture was stirred at room temperature for 2 hours, and the lithiation product was obtained by rotary evaporation. The lithiation product was dissolved in dimethyl sulfoxide at a concentration of 30 mg / mL under a nitrogen atmosphere, and tetramethyl-1,4-benzoquinone was added, wherein the molar ratio of tetramethyl-1,4-benzoquinone to the lithiation product was 1:1.5. The mixture was placed in an oven and reacted at 100°C for 1.5 hours, and then the temperature was increased to 150°C and reacted for 3 hours to obtain a blue-green solution, which is the lithium battery positive electrode binder.

[0078] Example 8:

[0079] Lithium hydroxide was used as the lithiation agent and mixed with 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) in a methanol / water mixed solvent (volume ratio 1:1), wherein the molar ratio of 2,5-dihydroxyterephthalic acid to lithium hydroxide was 1:2. The mixture was stirred at room temperature for 2 hours, and the lithiation product was obtained by rotary evaporation. The lithiation product was dissolved in N-methylpyrrolidone at a concentration of 30 mg / mL under a nitrogen atmosphere, and tetramethyl-1,4-benzoquinone was added, wherein the molar ratio of tetramethyl-1,4-benzoquinone to the lithiation product was 1:1. The mixture was placed in an oven and reacted at 100°C for 1.5 hours, and then the temperature was increased to 150°C and reacted for 3 hours to obtain a blue-green solution, which is the lithium battery positive electrode binder.

[0080] Example 9:

[0081] Lithium methoxide was used as the lithiation agent and mixed with 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) in a methanol / water mixed solvent (volume ratio 1:1). The molar ratio of 2,5-dihydroxyterephthalic acid to lithium hydroxide was 1:2. The mixture was stirred at room temperature for 2 hours, and the lithiation product was obtained by rotary evaporation. The lithiation product was dissolved in N-methylpyrrolidone at a concentration of 30 mg / mL under an argon atmosphere. Tetramethyl-1,4-benzoquinone was added, and the molar ratio of tetramethyl-1,4-benzoquinone to the lithiation product was 1:1.5. The mixture was placed in an oven and reacted at 100°C for 1.5 hours. Then, the temperature was increased to 150°C and reacted for 3 hours to obtain a blue-green solution, which is the lithium battery positive electrode binder.

[0082] Example 10:

[0083] Lithium carbonate was used as the lithiation agent and mixed with 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) in a methanol / water mixed solvent (volume ratio 1:1). The molar ratio of 2,5-dihydroxyterephthalic acid to lithium hydroxide was 1:3. The mixture was stirred at room temperature for 2 hours, and the lithiation product was obtained by rotary evaporation. The lithiation product was dissolved in N,N-dimethylformamide at a concentration of 30 mg / mL under an argon atmosphere. Tetramethyl-1,4-benzoquinone was added, with a molar ratio of tetramethyl-1,4-benzoquinone to the lithiation product of 1:1. The mixture was placed in an oven and reacted at 100°C for 1.5 hours. Then, the temperature was increased to 150°C and reacted for 3 hours to obtain a blue-green solution, which is the lithium battery positive electrode binder.

[0084] Example 11:

[0085] Lithium carbonate was used as the lithiation agent and mixed with 2,5-dihydroxyterephthalic acid (or 2,5-dihydroxybenzene-1,4-dicarboxylic acid) in a methanol / water mixed solvent (volume ratio 1:1). The molar ratio of 2,5-dihydroxyterephthalic acid to lithium hydroxide was 1:2. The mixture was stirred at room temperature for 2 hours, and the lithiation product was obtained by rotary evaporation. The lithiation product was dissolved in tetrahydrofuran at a concentration of 30 mg / mL under a helium atmosphere. Tetramethyl-1,4-benzoquinone was added, and the molar ratio of tetramethyl-1,4-benzoquinone to the lithiation product was 1:1.5. The mixture was placed in an oven and reacted at 100°C for 1.5 hours. Then, the temperature was increased to 150°C and reacted for 3 hours to obtain a blue-green solution, which is the lithium battery positive electrode binder.

[0086] Example 12:

[0087] The battery assembly and electrochemical performance testing methods are as follows:

[0088] (1) The CR2032 button cell was used for testing, with lithium metal as the negative electrode and Celgard2400 as the separator. The cells were assembled in an argon-protected glove box.

[0089] (2) The battery test window is 2.0-4.8 V (vs. Li + / Li), to perform constant current charge and discharge and rate performance tests, etc.

[0090] Test example:

[0091] The lithium-ion battery cathode binder prepared in Example 1 was subjected to XRD testing, and the results are as follows: Figure 1 As shown.

[0092] The lithium-ion battery cathode binder prepared in Example 1 was subjected to TEM testing, and the results are as follows: Figure 2 As shown. (Through) Figure 2 It can be seen that the morphology of the prepared lithium battery cathode binder is nanofiber-like;

[0093] The lithium-ion battery cathode binder prepared in Example 1 was subjected to Raman testing, and the results are as follows: Figure 3 As shown. (Through) Figure 3 It can be seen that at 1500 cm -1 ~1600 cm -1 A triple peak appeared at 1721 cm⁻¹, which is a characteristic peak of aromatic ring skeletal vibration. -1 The characteristic peak of C=O appears at 1253 cm⁻¹. -1 and 3008 cm -1 The peaks at these locations represent the characteristic peaks of CC and CH, respectively.

[0094] The solubility of the lithium-ion battery cathode binder prepared in Example 1 was tested, and the results are as follows: Figure 4 As shown, Figure b represents the state of the sample in Figure a after 48 hours; the solvents are 1-propylene carbonate, 2-water, 3-dimethyl sulfoxide, 4-tetrahydrofuran, 5-N'N-dimethylformamide, and 6-diethylene glycol dimethyl ether, respectively. Figure 4 It can be seen that the lithium battery cathode binder exhibits strong solvent stability in various common solvents.

[0095] The conductivity of the lithium-ion battery cathode binder prepared in Example 1 was tested, and the results are as follows: Figure 5 As shown. (Through) Figure 5 It can be seen that the conductivity of this multifunctional adhesive is much higher than that of common commercial conductive agents.

[0096] The contact angle of the lithium battery positive electrode binder prepared in Example 1 was tested, and the results are as follows: Figure 6 As shown, figures a and b represent the contact angles between the adhesive and H2O and LiPF6DMC-EC; figures c and d represent the contact angles between PVDF and H2O and LiPF6DMC-EC. Through Figure 6It can be seen that the contact angle between this binder and both H2O and electrolyte is smaller than that of PVDF, indicating that its wettability is better than that of PVDF and is more conducive to ion transport.

[0097] The flexibility of the lithium-ion battery cathode binder prepared in Example 1 was tested, and the results are as follows: Figure 7 As shown.

[0098] The method for fabricating coin cells using the lithium-ion battery positive electrode binder obtained by this invention:

[0099] 100 mg of benzo[a]dione difuran, 114 mg of tetramethyl-1,4-benzoquinone, and 67 mg of lithium carbonate were weighed and a lithium-ion battery positive electrode binder was prepared according to the method described in the example. The solution was filtered to remove most of the solvent, and the solution was washed several times with water to exchange the remaining small amount of solvent. The resulting product was frozen and then frozen in a freeze dryer for 12 hours to obtain a film-like product of the lithium-ion battery positive electrode binder. Through five repeated experiments, the mass of the film was found to be 50 ± 1 mg. Taking the average value, i.e., 100 mg of benzo[a]dione difuran yielded 50 mg of lithium-ion battery positive electrode binder.

[0100] 400 mg of lithium-rich manganese-based cathode material and 50 mg of KB were ground and mixed in an agate mortar for 10 min. The mixture was then transferred to a small glass bottle and placed in a vacuum oven to dry at 80°C for 8 h. After the powder was dried, 50 mg of the lithium battery cathode binder slurry prepared in Example 8 was added to form a slurry with a suitable viscosity. The bottle was then sealed with sealing glue and stirred for 12 h to form a uniformly dispersed cathode slurry.

[0101] The positive electrode slurry was coated onto the carbon-coated aluminum foil using the 100 μm side of a four-sided coating apparatus, and then thoroughly dried in a vacuum oven (80 °C for 12 h).

[0102] The dried positive electrode sheet was compacted using a roller press, and the rolled positive electrode sheet was cut into 12 mm diameter round pieces using a slicer for later use. Commercial lithium sheets were used as negative electrodes, Celgard 2400 separators were used as separators, and 1 M LiPF6 (EC:DMC = 1:1) electrolyte was used as electrolyte. The cells were assembled into coin cells in a glove box and aged for 12 h to obtain coin cells.

[0103] The lithium-ion battery cathode binder prepared in Example 3 was directly used in the lithium-ion battery cathode without adding any additional active materials or conductive agents. Its charge-discharge curve is shown below. Figure 8 As shown. (Through) Figure 8 It can be seen that when this lithium battery cathode binder is used alone as the cathode, its capacity is 203.7 mAh / g.

[0104] The lithium-ion battery positive electrode binder obtained in Example 3 was used to fabricate electrode sheets using the above method, and the peel strength was tested. The results are as follows: Figure 9 As shown. (Through) Figure 9 It can be seen that this adhesive has stronger bonding performance compared to PVDF.

[0105] The lithium-ion battery cathode binder obtained in Example 3 was used to assemble coin cells using the above method, and cycle performance tests were conducted. The results are as follows: Figure 10 As shown. (Through) Figure 10 It can be seen that the initial capacity of this lithium-ion battery cathode binder is 393.85 mAh / g at a rate of 0.1C, exceeding the theoretical capacity of lithium-rich manganese-based cathode materials. After 100 cycles, the capacity retention is 79.6%, similar to that of commercially available PVDF binders. At a rate of 1C, the initial capacity is 291.3 mAh / g, and after 100 cycles, the capacity retention is 84%.

[0106] Impedance tests were performed on the obtained button cells, and the results are as follows: Figure 11 As shown.

[0107] The specific capacity of the obtained button cells was tested, and the results are as follows: Figure 12 As shown. (Through) Figure 12 It can be seen that in the coin cell assembled with the lithium-ion battery cathode binder prepared by this invention, the actual specific capacity of the lithium-rich manganese-based cathode material can reach, exceeding the theoretical capacity of 378 mAh / g for lithium-rich manganese-based cathode materials. Therefore, the lithium-ion battery cathode binder prepared by the method described in this invention can significantly improve the specific capacity of lithium-rich manganese-based cathode materials when applied to lithium-ion batteries.

[0108] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a polymeric conductive adhesive, characterized in that... Includes the following steps: Step 1: Mix monomer A and initiator B in a certain proportion in the reactor, and add solvent to dissolve them; Step 2: Under an inert atmosphere, add a cyclizing agent to the system from Step 1 and carry out a heat treatment reaction under controlled conditions; Step 3: Wash, purify, and dry the reaction product, or disperse it in a liquid; The polymer monomer A is at least one of benzodione difuran and 2,5-dihydroxyterephthalic acid.

2. The preparation method according to claim 1, characterized in that: The initiator B is tetramethyl-1,4-benzoquinone; the molar ratio of the polymer monomer A to the initiator B is 1:0.1~20.

3. The preparation method according to claim 1, characterized in that: The cyclizing agent is at least one of carbonate, hydroxide, ammonia, and organometallic compounds, and its metal component is at least one of lithium, sodium, and potassium; the molar ratio of the polymer monomer A to the cyclizing agent is 1:1.5~20.

4. The preparation method according to claim 1, characterized in that: The solvent is one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, acetonitrile, and methanol.

5. The preparation method according to claim 1, characterized in that: The heating rate of the heat treatment is 2~10℃ / min, the temperature is 20~200℃, and the time is 0.1~72h.

6. A polymeric conductive adhesive, prepared according to any one of the preparation methods of claims 1-5, characterized in that... Its general structural formula is shown below: 。 7. The polymeric conductive adhesive according to claim 6, characterized in that... The structure of the polymer conductive adhesive is as follows: or .

8. The application of the polymeric conductive binder as described in claim 6 or 7 in lithium-ion batteries.

9. The application according to claim 8, characterized in that: When this binder is used in lithium-ion batteries, the binder, active material, conductive agent and solvent are mixed to obtain a positive electrode slurry, the positive electrode material is coated on the positive electrode foil material, and after drying, the positive electrode material of the lithium-ion battery is obtained.

10. The application according to claim 9, characterized in that: The active material comprises lithium-rich manganese-based cathode material, lithium iron phosphate, or NCM811; the conductive agent comprises Ketjen Black, Super P, carbon nanotubes, or acetylene black; the mass ratio of active material, conductive agent, and binder is 6~9:0~4:1.

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