Non-fluorine positive electrode binder for lithium ion battery and positive electrode plate

Abstract

Provided are a non-fluorine positive electrode binder for a lithium ion battery and a positive electrode plate, belonging to the technical field of lithium ion batteries. The technical problem solved is to provide a non-fluorine positive electrode binder for a lithium ion battery with good toughness. The non-fluorine positive electrode binder for a lithium ion battery comprises component A and component B, wherein component A is polyurea or polythiourea, component B is a polyacrylonitrile-based binder, and based on the total weight of component A and component B being 100%, the weight proportion of component A is 10-50%. The non-fluorine positive electrode binder for a lithium ion battery uses a polyacrylonitrile-based binder as the main component and polyurea or polythiourea as a flexible additive component, and is a fluorine-free solvent-based positive electrode binder that is safe and environmentally friendly. The binder has good adhesion and high flexibility, can overcome the deficiency of insufficient flexibility of existing PAN binders, and provides a new option for positive electrode binders of lithium ion batteries.

Description

A non-fluorinated positive electrode binder for lithium-ion batteries and a positive electrode sheet

[0001] Cross-reference to related applications

[0002] This application claims the benefit and priority of Chinese patent application CN2025103731134, filed on March 27, 2025, which is incorporated herein by reference and for all other purposes. Technical Field

[0003] This invention relates to a non-fluorinated positive electrode binder and a positive electrode sheet for lithium-ion batteries, belonging to the field of lithium-ion battery technology. Background Technology

[0004] Currently, commercially available lithium-ion batteries mostly use oil-based PVDF as a binder in their cathodes. PVDF preparation conditions are stringent, and its monomers, as fluorinated compounds, are strictly controlled. The fluorine atoms in its molecular structure have high electronegativity, making them prone to reacting with positively charged substances, such as metal ions, thus introducing metallic impurities into biomass. Furthermore, fluorinated polymers are difficult to degrade in the environment, can migrate long distances through soil, water, and air, accumulate in organisms, and can build up in terrestrial and aquatic ecosystems, causing negative environmental impacts. Therefore, there is a need to develop new fluorine-free lithium-ion cathode binders.

[0005] Chinese invention patent application number 201610677774 discloses an acrylonitrile copolymer adhesive using NMP as a solvent, comprising the following structural units by weight percentage: 78-95% acrylonitrile units, 1-10% acrylate units, 2-15% acrylamide units, and 2-8% acrylate units. This adhesive, with PAN as its main component, exhibits stronger polarity and higher adhesion to substrates and active materials compared to PVDF, along with better electrolyte resistance and superior kinetic properties, while also reducing material costs. However, the flexibility of this adhesive at room temperature does not fully meet the requirements for electrical processing performance, leading to material shedding and cracking during electrode processing, necessitating further improvement in flexibility.

[0006] Summary of the Invention

[0007] To address the above deficiencies, the technical problem solved by this invention is to provide a non-fluorinated cathode binder for lithium-ion batteries with good toughness.

[0008] The present invention relates to a non-fluorinated positive electrode binder for lithium-ion batteries, comprising component A and component B, wherein component A is polyurea or polythiourea, and component B is a polyacrylonitrile binder. Based on the total weight of components A and B being 100%, the weight percentage of component A is 10-50%.

[0009] In one specific embodiment, the weight percentage of component A is 15-45%.

[0010] In one specific embodiment, the number average molecular weight of component A is 12,000 to 200,000, and the number average molecular weight of component B is 200,000 to 3,000,000.

[0011] The structural formula of component A is one of the following structures:

[0012]

[0013] Formula I;

[0014] Wherein, X is selected from S or O, n is 2 to 2000, R1 and R2 are independently alkyl or aryl, R3 is aryl, and R4 is aryl. That is, component A of the present invention can be a straight-chain structure or a branched-chain structure.

[0015] In one embodiment of the present invention, component A is polymerized from an amine compound and a thiocarbonyl / carbonyl monomer.

[0016] The amine compound has one or two of the following structures: ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;

[0017] Where n1 is an integer from 1 to 10; n2 is an integer from 1 to 10; n3 is an integer from 1 to 10; n4 is an integer from 2 to 68; n5 is an integer from 5 to 88; n6 is an integer from 1 to 20; n7 is an integer from 1 to 20; n8 is an integer from 1 to 20; m2 is an integer from 9 to 39; m1 and m3 are integers greater than 0 and 3≤m1+m3≤6.

[0018] The sulfur carbonyl / carbonyl monomer is any one of the following monomers:

[0019] ; ; ; ; ; ; ; ; ; ; ; ; ; S+ S+ S+ S+ S+ .

[0020] In one specific embodiment, the molar ratio of the amine compound to the thiocarbonyl / carbonyl monomer is 1:1 to 5.

[0021] In one specific embodiment, the monomers of component B include the following monomers in parts by weight: 78-95 parts of acrylonitrile, 1-10 parts of acrylate monomers, and 2-15 parts of acrylamide monomers.

[0022] In one specific embodiment, the acrylate monomer is CH2=CR 1 -COOR 2 , where R 1 For -H or -CH3, R 2 The acrylamide monomer is alkyl or cycloalkyl; the acrylamide monomer is CH2=CR 3 CONHR4 , where R 3 For -H or -CH3, R 4 It can be -H, alkyl, cycloalkyl or aromatic.

[0023] In one specific embodiment, the acrylate monomer is at least one of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, and 2-ethylhexyl methacrylate; and the acrylamide monomer is at least one of acrylamide, N-methylacrylamide, N-ethylacrylamide, N-butylacrylamide, and 2-methylacrylamide.

[0024] The present invention also provides a positive electrode sheet for a lithium-ion battery.

[0025] The present invention relates to a lithium-ion battery positive electrode sheet, comprising a positive electrode material and an adhesive, wherein the adhesive is the non-fluorinated positive electrode binder for lithium-ion batteries described in this invention.

[0026] Commonly used cathode materials in this field are applicable to this invention. The cathode material includes a cathode active material, which can be one or more of lithium cobalt oxide (LCO), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel cobalt manganese oxide (NCM), or lithium nickel cobalt aluminum oxide (NCA). Furthermore, sodium-ion battery cathode materials and solid-state cathode materials are also applicable to this invention.

[0027] In one specific embodiment, the amount of adhesive used accounts for 0.5 to 3 wt% of the total solid content, preferably 1 wt% of the total solid content. The total solid content referred to in this invention is the content of solids other than solvents in the positive electrode slurry, generally including the total content of positive electrode active material, conductive agent, adhesive, etc.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention relates to a non-fluorinated positive electrode binder for lithium-ion batteries. It uses polyacrylonitrile-based binders as the main component and polyurea or polythiourea as flexible additives. It is a fluorine-free, solvent-based positive electrode binder, making it safe and environmentally friendly. This binder exhibits excellent adhesion and high flexibility, overcoming the shortcomings of existing PAN binders in terms of insufficient flexibility, thus providing a new option for lithium-ion battery positive electrode binders. Detailed Implementation

[0030] The present invention relates to a non-fluorinated positive electrode binder for lithium-ion batteries, comprising component A and component B, wherein component A is polyurea or polythiourea, and component B is a polyacrylonitrile binder. Based on the total weight of components A and B being 100%, the weight percentage of component A is 10-50%.

[0031] This invention relates to a non-fluorinated positive electrode binder for lithium-ion batteries, which uses polyacrylonitrile binders as the main component and polyurea or polythiourea as flexible additives to obtain a solvent-based positive electrode binder. This binder has good adhesion and high flexibility, and can overcome the shortcomings of insufficient flexibility in existing PAN binders.

[0032] In one specific embodiment, the weight percentage of component A is 15-45%.

[0033] In one specific embodiment, the number average molecular weight of component A is 12,000 to 200,000, and the number average molecular weight of component B is 200,000 to 3,000,000.

[0034] The structural formula of component A is one of the following structures:

[0035]

[0036] Formula I;

[0037] Wherein, X is selected from S or O, n is 2 to 2000, R1 and R2 are independently alkyl or aryl, R3 is aryl, and R4 is aryl. That is, component A of the present invention can be a straight-chain structure or a branched-chain structure.

[0038] In one embodiment of the present invention, component A is polymerized from an amine compound and a thiocarbonyl / carbonyl monomer.

[0039] The amine compound has one or two of the following structures: ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;

[0040] Where n1 is an integer from 1 to 10; n2 is an integer from 1 to 10; n3 is an integer from 1 to 10; n4 is an integer from 2 to 68; n5 is an integer from 5 to 88; n6 is an integer from 1 to 20; n7 is an integer from 1 to 20; n8 is an integer from 1 to 20; m2 is an integer from 9 to 39; m1 and m3 are integers greater than 0 and 3≤m1+m3≤6.

[0041] The sulfur carbonyl / carbonyl monomer is any one of the following monomers:

[0042] ; ; ; ; ; ;; ; ; ; ; ; ; ; S+ S+ S+ S+ S+ .

[0043] Among them, S+ For elemental S and Similarly, for mixtures of S+ For S and A mixture; S+ For S and A mixture of these substances... When these mixtures react, they can generate thiocarbonyl groups.

[0044] In one specific embodiment, the molar ratio of the amine compound to the thiocarbonyl / carbonyl monomer is 1:1 to 5.

[0045] Component A can be prepared using conventional methods in the art. In a specific embodiment of the present invention, it is prepared using the following method:

[0046] The amine compound and the thiocarbonyl / carbonyl monomer are added to the solvent and mixed. The mixture is stirred for 10–30 h to obtain the product. The product is then purified and dried to obtain the final product.

[0047] Component B is a commonly used PAN-based adhesive. In one specific embodiment, the monomers of component B include the following monomers in parts by weight: 78-95 parts acrylonitrile, 1-10 parts acrylate monomers, and 2-15 parts acrylamide monomers.

[0048] In one specific embodiment, the acrylate monomer is CH2=CR 1 -COOR 2 , where R 1 For -H or -CH3, R 2 The acrylamide monomer is alkyl or cycloalkyl; the acrylamide monomer is CH2=CR 3 CONHR 4 , where R 3 For -H or -CH3, R 4 It can be -H, alkyl, cycloalkyl or aromatic.

[0049] In one specific embodiment, the acrylate monomer is at least one of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, and 2-ethylhexyl methacrylate; and the acrylamide monomer is at least one of acrylamide, N-methylacrylamide, N-ethylacrylamide, N-butylacrylamide, and 2-methylacrylamide.

[0050] The present invention relates to a lithium-ion battery positive electrode sheet, comprising a positive electrode material and an adhesive, wherein the adhesive is the non-fluorinated positive electrode binder for lithium-ion batteries described in this invention.

[0051] Commonly used cathode materials in this field are applicable to this invention. The cathode material includes a cathode active material, which can be one or more of lithium cobalt oxide (LCO), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel cobalt manganese oxide (NCM), or lithium nickel cobalt aluminum oxide (NCA). Furthermore, sodium-ion battery cathode materials and solid-state cathode materials are also applicable to this invention.

[0052] In one specific embodiment, the amount of adhesive used accounts for 0.5 to 3 wt% of the total solid content, preferably 1 wt% of the total solid content. The total solid content referred to in this invention is the content of solids other than solvents in the positive electrode slurry, generally including the total content of positive electrode active material, conductive agent, adhesive, etc.

[0053] The specific embodiments of the present invention will be further described below with reference to examples, but the present invention is not limited to the scope of the embodiments described herein.

[0054] Example 1

[0055] 0.105 mol of amine compound (N,N-dimethylformamide) was added to a 50 mL solution (0.105 mol) of 1,1′-thiocarbonyldiimidazole, and the mixture was stirred at 25 °C for 24 hours. 100 mL of chloroform was added to the solution, and the diluted mixture was then poured into 1.5 L of diethyl ether to obtain a precipitate. The precipitate was dissolved in 50 mL of chloroform, and the mixture was then subjected to two reprecipitation processes with chloroform / methanol. The insoluble fraction was collected by centrifugation, and the precipitate was dried in a vacuum oven at 140 °C for 12 hours to obtain polythiourea.

[0056] The amine compounds used are n2=2.

[0057] The number-average molecular weight of this polythiourea is 12,500.

[0058] The preparation method of polyacrylonitrile adhesives is as follows:

[0059] 900 parts of distilled water were added to a reaction vessel, stirring was started, and high-purity nitrogen was purged for 1 hour to remove oxygen. Then, 4 parts of methyl acrylate, 12 parts of acrylamide, and 84 parts of acrylonitrile were added. The mixture was heated to 60°C under an inert atmosphere and held at that temperature. Then, 5 parts of a 20% ammonium persulfate initiator solution were added to initiate the reaction, which was stopped after 4 hours. The adhesive was obtained after filtration, drying, pulverizing, and sieving. The number average molecular weight of the adhesive was 1245560.

[0060] The polythiourea was blended with a polyacrylonitrile binder at a mass ratio of 10:90 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0061] Example 2

[0062] Polythiourea was prepared using the method described in Example 1, wherein the amine compound used was... The number-average molecular weight of this polythiourea is 16,500.

[0063] The preparation method of the polyacrylonitrile adhesive is the same as that in Example 1.

[0064] The polythiourea was blended with a polyacrylonitrile binder at a mass ratio of 20:80 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0065] Example 3

[0066] Polythiourea was prepared using the method described in Example 1, and the thiourea polymer used was...

[0067] The preparation method of polyacrylonitrile adhesives is as follows:

[0068] 900 parts of distilled water were added to a reaction vessel, stirring was started, and high-purity nitrogen was purged for 1 hour to remove oxygen. Then, 4 parts of methyl acrylate, 5 parts of acrylamide, and 91 parts of acrylonitrile were added. The mixture was heated to 60°C under an inert atmosphere and held at that temperature. Then, 5 parts of a 20% ammonium persulfate initiator solution were added to initiate the reaction, which was stopped after 4 hours. The adhesive was obtained after filtration, drying, pulverizing, and sieving. The number average molecular weight of the adhesive was 1,685,750.

[0069] The polythiourea was blended with a polyacrylonitrile binder at a mass ratio of 15:85 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0070] Example 4

[0071] Polythiourea was prepared using the method described in Example 1, wherein the amine compound used was... and The molar ratio of the two amine compounds is 9:1, and the number-average molecular weight of the polythiourea is 19,800.

[0072] The preparation method of the polyacrylonitrile adhesive is the same as that in Example 1.

[0073] The polythiourea was blended with a polyacrylonitrile binder at a mass ratio of 35:65 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0074] Example 5

[0075] 1,1′-carbonyldiimidazole (1 mmol) was added to a 15 mL solution of an amine compound (1 mmol) in N-methylpyrrolidone, and the mixture was stirred at 60 °C for 24 hours. The mixture was cooled to room temperature and poured into acetone (1 L). The precipitate was separated by filtration and washed with excess methanol. The precipitate was dried in a vacuum oven at 140 °C for 12 hours to obtain polyurea.

[0076] The amine compounds used are .

[0077] The number-average molecular weight of this polyurea is 13,500.

[0078] The preparation method of polyacrylonitrile adhesives is as follows:

[0079] 900 parts of distilled water were added to a reaction vessel, stirring was started, and high-purity nitrogen was purged for 1 hour to remove oxygen. Then, 4 parts of butyl acrylate, 12 parts of acrylamide, and 84 parts of acrylonitrile were added. The mixture was heated to 60°C under an inert atmosphere and held at that temperature. Then, 5 parts of a 20% ammonium persulfate initiator solution were added to initiate the reaction, which was stopped after 4 hours. The adhesive was obtained after filtration, drying, pulverizing, and sieving. The number average molecular weight of the adhesive was 891,350.

[0080] The polyurea was blended with a polyacrylonitrile binder at a mass ratio of 15:85 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0081] Example 6

[0082] Polyurea was prepared using the method described in Example 5, wherein the amine compound used was... n2=3.

[0083] The number-average molecular weight of this polyurea is 26,500.

[0084] The preparation method of the polyacrylonitrile adhesive is the same as that in Example 1.

[0085] The polyurea was blended with a polyacrylonitrile binder at a mass ratio of 35:65 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0086] Example 7

[0087] Polythiourea was prepared using the method described in Example 5, wherein the amine compound used was... The number-average molecular weight of this polyurea is 22,500.

[0088] The preparation method of the polyacrylonitrile adhesive is the same as that in Example 1.

[0089] The polyurea was blended with a polyacrylonitrile binder at a mass ratio of 25:75 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0090] Comparative Example 1

[0091] Polyacrylonitrile binders are used as the positive electrode binders for lithium-ion batteries.

[0092] The preparation method of polyacrylonitrile adhesives is as follows:

[0093] 900 parts of distilled water were added to a reaction vessel, stirring was started, and high-purity nitrogen was purged for 1 hour to remove oxygen. Then, 4 parts of methyl acrylate, 12 parts of acrylamide, and 84 parts of acrylonitrile were added. The mixture was heated to 60°C under an inert atmosphere and held at that temperature. Then, 5 parts of a 20% ammonium persulfate initiator solution were added to initiate the reaction, which was stopped after 4 hours. The adhesive was obtained after filtration, drying, pulverizing, and sieving. The number average molecular weight of the adhesive was 1245560.

[0094] Comparative Example 2

[0095] Commercially available PVDF is used as the binder for the positive electrode of lithium-ion batteries.

[0096] Comparative Example 3

[0097] The polythiourea prepared in Example 1 was blended with a polyacrylonitrile binder at a mass ratio of 55:45 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0098] Comparative Example 4

[0099] The polyurea prepared in Example 6 was blended with a polyacrylonitrile binder at a mass ratio of 55:45 to obtain a non-fluorinated positive electrode binder for lithium-ion batteries.

[0100] Performance testing:

[0101] The binder used in the examples and comparative examples was used to prepare the positive electrode slurry. The specific preparation method is as follows:

[0102] The obtained binder was dissolved in NMP, and then added to conductive carbon black and lithium cobalt oxide in a ratio of 98%:1%:1%. The mixture was stirred at high speed for 4 hours. The resulting slurry was then coated onto aluminum foil using a battery coating machine and dried at 110 °C. The dried electrode sheets were then rolled to achieve an areal density of 240–280 g / m³. 2 The compacted density is 4.2 g / cm³. 3.

[0103] Film tensile test method:

[0104] Lay the PET film flat on a clean glass plate, and drop a suitable amount of ethanol between the PET film and the glass plate to facilitate a tight adhesion. Using a disposable dropper, take 20 mL of the test adhesive solution (after centrifugation and defoaming) and drop it onto the flat PET film. Adjust the thickness of the adjustable scraper according to the solid content of the adhesive solution to control the thickness of the dried adhesive solution to 0.03 ± 0.005 mm. Scrape the adhesive solution onto the PET film to form a uniform thickness film. Then transfer the sample to a forced-air oven at 110℃ and bake for 60 min (the glass plate must be placed horizontally; otherwise, the adhesive solution will flow during baking, causing uneven sample thickness). Take a uniformly thick film from the dried adhesive film and accurately cut it into strips 100 mm long and 10 mm wide using a double-edged blade. The initial gauge length for the test is 50 mm, the tensile speed is 200 mm / min, and the number of tests is greater than or equal to 3. The ambient temperature is 10–38℃, and the humidity is 25–30% RH.

[0105] Adhesion strength test method:

[0106] Peel strength was measured using a 180° high-precision micromechanical peel strength tester (Shenzhen Kaiqiangli Co., Ltd., China) at a constant displacement rate of 20.0 mm / min, using 25 mm tape (adhered to the active material side). The load and displacement used to peel the active material from the current collector were continuously recorded. National Standard: GB / T2790-1995. Ambient humidity ≤30% RH.

[0107] Solid content test method (instrument model: METTLER TOLEDO, LHS120-A, Mettler Todov Instruments (Shanghai) Co., Ltd.):

[0108] Turn on the power of the rapid drying moisture analyzer and preheat for 1 hour. After calibrating the instrument, select the sample (heated to 150℃), peel it, and press the start button to begin heating the drying pan. After heating stops, wait for the moisture analyzer to cool down until the temperature display on the screen changes to the mass display before performing the moisture content analysis at the required temperature. Use a syringe to draw approximately 2.5 g of sample onto the weighing pan and use a PTFE scraper to level the sample. Close the top cover and wait for the reading to stabilize before pressing the "Start" button to begin the test. When the sample reaches a constant weight at 150℃ (remaining constant for 70 s), the moisture analyzer will automatically stop heating and emit a beep. Record the test data.

[0109] Viscosity test method (DV2TLV, Borelfeld, USA):

[0110] Turn on the power to the thermostat bath and raise the oil temperature to 25°C, maintaining this temperature (temperature fluctuation should not exceed ±0.2°C). Pour approximately 350 g of the sample to be tested into a clean, dry measuring cup, seal it with a rubber stopper fitted with a thermometer, and then place it in the thermostat bath to heat the sample to 25°C (stirring approximately every 5 minutes to ensure uniform concentration and temperature), then maintain this temperature for 10 minutes before testing. Measure the viscosity of the sample at 25°C using a digital viscometer. Use a 64# rotor at a speed of 30 RPM. The test duration is 3 minutes, and data acquisition lasts for 2 minutes.

[0111] The test results are shown in Tables 1 and 2.

[0112] Table 1

[0113]

[0114] Table 2

[0115]

[0116] The binders used in the examples all achieved compaction densities comparable to commercial PVDF, had higher elongation at break than commercial PVDF, and exhibited superior flexibility compared to the comparative examples, while also possessing high adhesive strength. Comparative Examples 3 and 4, due to their higher content of flexible components, were prone to rebound after electrode rolling, and their compaction could not reach 4.2 g / cm³. 3 .

Claims

1. A non-fluorinated positive electrode binder for lithium-ion batteries, characterized in that: It includes component A and component B, wherein component A is polyurea or polythiourea, and component B is a polyacrylonitrile adhesive. The weight percentage of component A is 10-50% based on the total weight of components A and B as 100%.

2. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 1, characterized in that: Component A accounts for 15-45% of the total weight.

3. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 1, characterized in that: The number average molecular weight of component A is 12,000–200,000, and the number average molecular weight of component B is 200,000–3,000,000.

4. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 1, characterized in that: Component A has any of the following structural formulas:  ； ； ；  Wherein, X is selected from S or O, n is 2 to 2000, R1 and R2 are alkyl or aryl, R3 is aryl, and R4 is aryl.

5. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 4, characterized in that: Component A is polymerized from amine compounds and thiocarbonyl / carbonyl monomers; The amine compound has one or two of the following structures: ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； Where n1 is an integer from 1 to 10; n2 is an integer from 1 to 10; n3 is an integer from 1 to 10; n4 is an integer from 2 to 68; n5 is an integer from 5 to 88; n6 is an integer from 1 to 20; n7 is an integer from 1 to 20; n8 is an integer from 1 to 20; m2 is an integer from 9 to 39; m1 and m3 are integers greater than 0 and 3 ≤ m1 + m3 ≤ 6; The sulfur carbonyl / carbonyl monomer is any one of the following monomers: ； ； ； ； ； ； ； ； ； ； ； ； ； ；S+ ；S+ ；S+ ；S+ ；S+ ；S+ 。 6. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 5, characterized in that: The molar ratio of amine compounds and sulfur carbonyl / carbonyl monomers is 1:1 to 5.

7. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 1, characterized in that: The monomers in component B include the following monomers in parts by weight: 78-95 parts acrylonitrile, 1-10 parts acrylate monomers, and 2-15 parts acrylamide monomers.

8. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 7, characterized in that: The acrylate monomer is CH2=CR 1 -COOR 2 , where R 1 For -H or -CH3, R 2 The acrylamide monomer is alkyl or cycloalkyl; the acrylamide monomer is CH2=CR 3 CONHR 4 , where R 3 For -H or -CH3, R 4 It can be -H, alkyl, cycloalkyl or aromatic.

9. The non-fluorinated positive electrode binder for lithium-ion batteries according to claim 8, characterized in that: The acrylate monomers are at least one of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, and 2-ethylhexyl methacrylate; and the acrylamide monomers are at least one of acrylamide, N-methylacrylamide, N-ethylacrylamide, N-butylacrylamide, and 2-methylacrylamide.

10. A lithium-ion battery positive electrode sheet, comprising a positive electrode material and a binder, characterized in that: The adhesive is the non-fluorinated positive electrode adhesive for lithium-ion batteries according to any one of claims 1 to 9.

11. The lithium-ion battery positive electrode sheet according to claim 10, characterized in that: The amount of adhesive used accounts for 0.5 to 5 wt% of the total solids.

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