A high carbonization rate resin material and its preparation method and application

Abstract

The present invention discloses a high-carbonization resin material, its preparation method, and application. The present invention uses a reaction precursor containing a nitronaphthalene group and a reaction monomer containing an aminophenyl ether group as reaction raw materials to form a three-dimensional cross-linked network. Its carbonization rate can reach more than 85%, which is significantly higher than that of traditional resin materials. Through the synergistic effect of nitrogen doping and 3-aminopropyltriethoxysilane coupling agent grafting, a three-dimensional conductive network structure is constructed. When applied to silicon-carbon negative electrode materials, it can effectively suppress the peeling of silicon particles during the cycle process. It can be used as a high-temperature resistant resin. At the same time, a stable, high-quality compound film can be formed by various liquid-phase film-forming methods.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a high carbonization rate resin material, a preparation method and application thereof. Background Art

[0002] In recent years, the application of silicon-carbon anode materials in power batteries has grown rapidly, with annual production exceeding 1,000 tons and expected to gradually reach 10,000 tons. Although silicon-carbon materials are relatively unsuitable for use in prismatic battery structures, their application rate has increased significantly in large cylindrical battery designs. Furthermore, the use of silicon-carbon-based materials in the consumer electronics market, particularly in power tools and smart wearable devices, has also been steadily increasing.

[0003] Currently, the main problems facing silicon-carbon negative electrode materials are low initial efficiency and high cost. The efficiency of silicon-carbon materials is low when they are not pre-lithiated, and their initial efficiency needs to be increased to about 90% through pre-lithiation or pre-magnesiation, but this will increase the price of the material. In addition, the volume expansion problem of silicon-carbon materials is prominent. Although it can be optimized and controlled by refining the particle size to below 100 nanometers, because they are similar in capacity to silicon-oxygen materials and both require carbon coating, the key difference between the two is mainly reflected in the material doping ratio and adaptability to different battery forms.

[0004] Currently, the use of porous carbon-coated silicon is considered a promising technology for future power batteries. The porous carbon's pores enhance the uniformity and expansion resistance of nano-silicon, reducing costs and eliminating the need for pre-lithiation treatment. It can effectively reduce powder particle size and adjust size distribution, helping to alleviate stress and deformation caused by the silicon during lithium ion insertion and extraction.

[0005] CN118782747A discloses a metal nitride and porous carbon coated silicon negative electrode material, preparation method and application, which relates to the field of lithium ion battery technology. The preparation method includes the following steps: (1) mixing nano silicon particles, polymer compound carbon source, metal compound, nitrogen source and dispersant into slurry; (2) grinding the slurry for the first time, drying and removing the dispersant; grinding for the second time to obtain a precursor; (3) carbonizing the precursor at high temperature under a protective gas atmosphere to obtain a metal nitride and porous carbon coated silicon negative electrode material. The metal nitride and porous carbon coated silicon negative electrode material integrates metal nitride nanoparticles and graphitized porous carbon into silicon nanoparticles, improves the conductive properties of the silicon negative electrode material, and has lower activation energy, higher conductivity and greater Li + Diffusion coefficient.

[0006] The core-shell structure and yolk-shell structure of silicon-carbon negative electrode materials, by precisely controlling the thickness of the carbon layer (5-10nm) and the pore distribution (20-50nm pore size accounts for >80%), can not only reserve buffer space for the expansion of silicon particles, but also form a continuous conductive network (conductivity >100 S / cm), significantly improving the lithium ion diffusion rate and reducing electrode polarization. The selection of porous carbon precursors can achieve uniform dispersion of silicon particles through hierarchical pore structure and surface functional group modification, and enhance the interfacial bonding force through CO-Si covalent bonds, thereby increasing the cycle life from 100 times of traditional silicon negative electrodes to more than 500 times. Therefore, high carbonization rate resin materials can be used as porous carbon precursors for new silicon-carbon negative electrode packaging materials, which is crucial to the performance optimization of silicon-carbon negative electrode materials and can greatly improve their performance and efficiency. Summary of the Invention

[0007] The present invention addresses the problems of low carbon content, insufficient thermal stability and mechanical stability in silicon-carbon negative electrode coating materials, and provides a resin material with a high carbonization rate. The material has high stability, cross-linking degree and solvent resistance, and exhibits good film-forming properties after liquid phase film formation. It is expected to be applied to high-temperature resistant resins, silicon-carbon negative electrode packaging materials, silicon-carbon negative electrode precursors and other fields.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] A high carbonization rate resin material having a structure as shown in formula (I):

[0010] (I)

[0011] Wherein, x:y is (0.5-1):(2-4); R1 and R2 in the biphenyl unit are independently selected from hydrogen or any halogen element group containing fluorine, chlorine, bromine, iodine, astatine, and thiophene.

[0012] The weight average molecular weight of the high carbonization rate resin material is 10,000-50,000.

[0013] The high carbonization rate resin material has a silicon content of 5%-15%, a carbon content of 60%-90%, and a hydrogen content of 2%-10% by mass.

[0014] The present invention also provides a method for preparing the resin material with a high carbonization rate, comprising the steps of:

[0015] Step 1: Under the protection of an inert gas, a precursor containing a nitronaphthalene group, a reactive monomer containing an aminophenyl ether group, a crosslinking agent containing a biphenyl group, and an initiator are mixed in a solvent to react to obtain a prepolymer;

[0016] Step 2: grafting the prepolymer and 3-aminopropyltriethoxysilane in a solvent, and separating and purifying the product to obtain the resin material with a high carbon yield.

[0017] The precursor containing the nitronaphthalene group includes one or more of 1,5-dinitronaphthalene and 1,6-dinitronaphthalene;

[0018] The reactive monomer containing an aminophenyl ether group includes 4,4'-diaminodiphenyl ether;

[0019] The cross-linking agent containing a biphenyl group includes one or more of 4,4'-dibromobiphenyl, 4,4'-diaminooctafluorobiphenyl, 3-amino-4'-fluorobiphenyl, and 4-bromo-4'-iodobiphenyl.

[0020] The initiator includes one or more of palladium-carbon catalyst, Speier catalyst, Custer catalyst, sodium trimethylsiliconate, potassium trimethylsiliconate, sodium phenyldimethylsiliconate, potassium phenyldimethylsiliconate, tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide, benzyltributylammonium hydroxide, tetrahexylammonium hydroxide, sulfuric acid, hydrochloric acid, nitric acid, perchloric acid, and trifluoromethanesulfonic acid. The mass of the initiator input is 0.01%-1% of the total mass of all reaction monomers.

[0021] The solvent includes dipentane, hexane, heptane, octane, benzene, toluene, xylene, acetone, methanol, ethanol, butanol, ethylene glycol butyl ether, diethylene glycol butyl ether, triethylene glycol butyl ether, tetraethylene glycol butyl ether, ethylene glycol hexyl ether, diethylene glycol hexyl ether, diethylene glycol-2-ethylhexyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, 2-methoxyethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate One or more of esters, propylene glycol ethyl ether acetate, propylene glycol-1,2-dimethyl ether, propylene glycol diacetate, methyl methoxy acetate, dimethyl ketone, cyclohexanone, diisobutyl ketone, ethyl acetate, butyl acetate, 2-methylpropyl acetate, 3-methylbutyl acetate, ethyl lactate, methyl 3-methoxypropionate, cyclopentyl methyl ether, 4-hydroxy-4-methyl-2-pentanone, 3,5,5-trimethyl-1-hexanol, diethyl ether, dibutyl ether, tetrahydrofuran, dichloromethane, chloroform, and carbon tetrachloride.

[0022] In step 1, the reaction temperature is 90-150° C., and the reaction time is 12-72 h.

[0023] In step 2, the grafting reaction temperature is 60-100° C., and the reaction time is 2-10 h.

[0024] The molar ratio of the precursor containing nitronaphthalene groups, the reactive monomer containing aminophenyl ether groups, and the cross-linking agent containing biphenyl groups is (0.5-1): (1-2.5): (1-2.5).

[0025] The high carbonization rate resin material of the present invention has excellent high-temperature stability and good film-forming properties, and can be used as a high-temperature resistant resin, a silicon-carbon negative electrode wrapping material, or a silicon-carbon negative electrode precursor.

[0026] The present invention also provides a high carbonization rate resin film, comprising the high carbonization rate resin.

[0027] Preferably, the high carbonization rate resin film is formed by liquid phase film formation of the high carbonization rate resin, dissolving the resin in a solvent, filtering, and then forming a film by spin coating, brush coating, or standing. The resin film has good film forming properties and excellent thermal stability and mechanical stability.

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

[0029] (1) This reaction system innovatively uses a reaction precursor containing a nitronaphthalene group and a reaction monomer containing an aminophenyl ether group as reaction raw materials to form a three-dimensional cross-linked network. Its carbonization rate can reach more than 85%, which is significantly higher than that of traditional resin materials.

[0030] (2) The resin reaction system of the present invention constructs a three-dimensional conductive network structure through the synergistic effect of nitrogen doping and 3-aminopropyltriethoxysilane coupling agent grafting, which can effectively inhibit the peeling of silicon particles during the cycle when applied to silicon-carbon negative electrode materials.

[0031] (3) The high carbonization rate resin material of the present invention has good thermal stability and mechanical stability and can be used as a high-temperature resistant resin. At the same time, it can form a stable, high-quality compound film through a variety of liquid phase film forming methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The thermogravimetric analysis curves of the high carbonization rate resin materials prepared in Example 1 and Example 2 are shown.

[0033] Figure 2 This is the infrared spectrum of the high carbonization rate resin material in Example 1.

[0034] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the high carbonization rate resin material in Example 1.

[0035] Figure 4 This is an electrochemical voltammetric cycle test diagram of the high carbonization rate resin material prepared in Example 1. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art will make modifications or equivalent substitutions based on understanding the technical solution of the present invention, without departing from the spirit and scope of the technical solution of the present invention, and all should be encompassed within the protection scope of the present invention.

[0037] The raw materials used in the following specific embodiments are all purchased from the market.

[0038] Example 1

[0039] 1,5-dinitronaphthalene, ethanol solution and 5% palladium-carbon catalyst of the total weight of all reaction monomers were added to a 500 mL three-necked reactor, and the mixture was stirred and heated to 60° C. for four hours under a nitrogen atmosphere. After purification and filtration, 4,4'-dibromobiphenyl and 4,4'-diaminodiphenyl ether were added, and the mixture was stirred and heated to 120° C. under a nitrogen atmosphere. After the reaction was continued for 24 hours, the product was separated by column chromatography to obtain a prepolymer; the molar ratio of 1,5-dinitronaphthalene, 4,4'-dibromobiphenyl and 4,4'-diaminodiphenyl ether in the reaction raw materials was 0.5:1:1.

[0040] The prepolymer was added into an ethanol solution of 3-aminopropyltriethoxysilane with a mass fraction of 5% and immersed at 80°C for 6 hours. The product was separated by permeation through an analytical sieve and column chromatography to obtain a high carbonization rate resin material. The carbonization rate of the material was 87.2% and the weight-average molecular weight was 17854.

[0041] Example 2

[0042] The only difference from Example 1 is that 1,6-dinitronaphthalene is added in this Example 2, and the others are the same as Example 1. For further explanation, this Example 2 is as follows:

[0043] 1,6-dinitronaphthalene, ethanol solution and 5% palladium-carbon catalyst of the total weight of all reaction monomers were added to a 500 mL three-necked reactor, and the mixture was stirred and heated to 60° C. for four hours under a nitrogen atmosphere. After purification and filtration, 4,4'-dibromobiphenyl and 4,4'-diaminodiphenyl ether were added, and the mixture was stirred and heated to 120° C. under a nitrogen atmosphere. The reaction was continued for 24 hours, and then the prepolymer was obtained after column chromatography separation. The molar ratio of 1,6-dinitronaphthalene, 4,4'-dibromobiphenyl and 4,4'-diaminodiphenyl ether in the reaction raw materials was 0.5:1:1.

[0044] The prepolymer was added into a 5% by mass 3-aminopropyltriethoxysilane ethanol solution and immersed at 80°C for 6 hours. The product was separated by analytical sieve permeation and column chromatography to obtain a high carbonization rate resin material. The carbonization rate of the material was 83.7% and the weight-average molecular weight was 18593.

[0045] Figure 1 The thermogravimetric analysis curves of the high carbonization rate resin materials prepared in Examples 1 and 2 show that both Examples 1 and 2 have high thermal decomposition temperatures of above 200°C and close to 300°C, indicating good thermal stability. 5% =253°C, T of Example 2 5% =247℃.

[0046] Figure 2 This is the infrared spectrum of the high carbonization rate resin material prepared in Example 1. It can be seen from the figure that 2964cm -1 The peak of methyl CH stretching vibration is 2874 cm -1 The NH absorption peak is at 1604 cm -1 、1496cm -1 、1450cm -1 、1407cm -1 The peak of benzene ring skeleton stretching vibration is 1080cm -1 The absorption peak is Si-O-Si, which shows that the target structure compound is synthesized.

[0047] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the high carbonization rate resin material prepared in Example 1. It can be seen from the figure that the peak at 2.05 ppm is the characteristic peak of deuterated acetone, 7.2-7.7 ppm is the characteristic peak of the hydrogen atoms in the benzene ring, the absorption peak at 1.5-3.8 ppm is the absorption peak of the hydrogen atoms in 3-aminopropyltriethoxysilane, and the absorption peak at 0.24 ppm is the characteristic peak of Si-O-Si.

[0048] Figure 4 This is an electrochemical voltammetric cycle test graph obtained by dissolving the high carbonization rate resin material prepared in Example 1 in a solvent and adding an electrolyte in a three-electrode test system. The selected voltage range is -0.4V-1.2V, and the number of test cycles is 500. It can be seen from the figure that the resin material has symmetrical redox peaks at 0.2V and 0.6V, indicating that the resin material has good reversibility in the electrochemical redox process. At the same time, after 500 cycles, the peak area loss is very small, only 10.7%, indicating that it has good cycle stability and is expected to be used in silicon-carbon negative electrode packaging materials.

[0049] Application Example 1

[0050] The high carbonization rate resin material prepared in Example 1 is filtered using a PTFE filter membrane (pore size of 0.1 μm), 0.2 g of the high carbonization rate resin is dissolved in 9.8 g of N-methylpyrrolidone solvent to obtain a high carbonization rate resin coating sample 1, and the high carbonization rate resin coating sample 1 is spin-coated to form a film.

[0051] Application Example 2

[0052] The high carbonization rate resin material prepared in Example 2 is filtered using a PTFE filter membrane (pore size of 0.1 μm), 0.2 g of the high carbonization rate resin is dissolved in 9.8 g of N-methylpyrrolidone solvent to obtain a high carbonization rate resin coating sample 2, and the high carbonization rate resin coating sample 2 is spin-coated into a film.

[0053] Organic element analysis and film-forming property characterization were performed on the above Application Examples 1 and 2, and the film thickness and the content of each element were obtained as shown in Table 1.

[0054] Table 1 Elemental analysis and film thickness of thin films of Application Example 1 and Application Example 2

[0055]

[0056] FL is the film thickness obtained after the solvent resistance test of the compound film obtained by spin coating and drying in Application Example 1 and Application Example 2 (after soaking in organic solvents of propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), and propylene glycol ethyl ether (PGEE) for 10 minutes, and then drying the surface solvent by spin coating), indicating its good film-forming performance and solvent resistance.

[0057] In summary, the present invention uses a reaction precursor containing a nitronaphthalene group and a reaction monomer containing an aminophenyl ether group as reaction raw materials to obtain a resin material with a high carbonization rate, a high degree of crosslinking, a high film-forming property and good solvent resistance. It breaks through the bottleneck of the low carbonization rate of a single component in the silicon-carbon negative electrode material and has good application prospects in many fields such as high-temperature resistant resins, silicon-carbon negative electrode packaging materials, and silicon-carbon negative electrode precursors.

[0058] The various aspects, embodiments, and features of the present invention should be considered in all respects as illustrative and not limiting, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0059] In the preparation method of the present invention, the order of the steps is not limited to the order listed. Persons skilled in the art will appreciate that variations in the order of the steps are within the scope of the present invention without inventive effort. Furthermore, two or more steps or actions may be performed simultaneously.

[0060] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit its implementation. Persons skilled in the art may make various modifications, additions, or substitute similar methods for the described specific embodiments. It is not necessary and impossible to provide comprehensive examples of all implementations here. However, obvious variations or modifications arising from the essential spirit of the present invention remain within the scope of protection of the present invention, and interpreting them as any additional limitations would be contrary to the spirit of the present invention.

Claims

1. A high carbonization rate resin material, characterized in that: It has the structure shown in formula (I): （I） Wherein, x:y is (0.5-1):(2-4); R1 and R2 in the biphenyl unit are independently selected from hydrogen or any halogen element group containing fluorine, chlorine, bromine, iodine, astatine, and thiophene.

2. The high carbonization rate resin material according to claim 1, characterized in that: The weight average molecular weight of the high carbonization rate resin material is 10,000-50,000.

3. The high carbonization rate resin material according to claim 1, characterized in that: The high carbonization rate resin material has a silicon content of 5%-15%, a carbon content of 60%-90%, and a hydrogen content of 2%-10% by mass.

4. A method for preparing a high carbonization rate resin material according to any one of claims 1 to 3, characterized in that: Including steps: Step 1: Under the protection of an inert gas, a precursor containing a nitronaphthalene group, a reactive monomer containing an aminophenyl ether group, a crosslinking agent containing a biphenyl group, and an initiator are mixed in a solvent to react to obtain a prepolymer; Step 2: grafting the prepolymer and 3-aminopropyltriethoxysilane in a solvent, and separating and purifying the product to obtain the resin material with a high carbon yield.

5. The method for preparing a resin material with a high carbonization rate according to claim 4, wherein: The precursor containing the nitronaphthalene group includes one or more of 1,5-dinitronaphthalene and 1,6-dinitronaphthalene; The reactive monomer containing an aminophenyl ether group includes 4,4'-diaminodiphenyl ether; The cross-linking agent containing a biphenyl group includes one or more of 4,4'-dibromobiphenyl, 4,4'-diaminooctafluorobiphenyl, 3-amino-4'-fluorobiphenyl, and 4-bromo-4'-iodobiphenyl.

6. The method for preparing a resin material with a high carbonization rate according to claim 4, wherein: The initiator includes one or more of palladium carbon catalyst, Speier catalyst, and Custer catalyst, and the input mass of the initiator is 0.01%-1% of the total mass of all reaction monomers; The solvent includes dipentane, hexane, heptane, octane, benzene, toluene, xylene, acetone, methanol, ethanol, butanol, ethylene glycol butyl ether, diethylene glycol butyl ether, triethylene glycol butyl ether, tetraethylene glycol butyl ether, ethylene glycol hexyl ether, diethylene glycol hexyl ether, diethylene glycol-2-ethylhexyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, 2-methoxyethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate One or more of esters, propylene glycol ethyl ether acetate, propylene glycol-1,2-dimethyl ether, propylene glycol diacetate, methyl methoxy acetate, dimethyl ketone, cyclohexanone, diisobutyl ketone, ethyl acetate, butyl acetate, 2-methylpropyl acetate, 3-methylbutyl acetate, ethyl lactate, methyl 3-methoxypropionate, cyclopentyl methyl ether, 4-hydroxy-4-methyl-2-pentanone, 3,5,5-trimethyl-1-hexanol, diethyl ether, dibutyl ether, tetrahydrofuran, dichloromethane, chloroform, and carbon tetrachloride.

7. The method for preparing a resin material with a high carbonization rate according to claim 4, wherein: In step 1, the reaction temperature is 90-150° C. and the reaction time is 12-72 h; In step 2, the grafting reaction temperature is 60-100° C., and the reaction time is 2-10 h.

8. The method for preparing a resin material with a high carbonization rate according to claim 4, wherein: The molar ratio of the precursor containing nitronaphthalene groups, the reactive monomer containing aminophenyl ether groups, and the cross-linking agent containing biphenyl groups is (0.5-1): (1-2.5): (1-2.5).

9. Use of the high carbonization rate resin material according to any one of claims 1 to 3 as a high temperature resistant resin, a silicon-carbon negative electrode wrapping material, or a silicon-carbon negative electrode precursor.

10. A high carbonization rate resin film, characterized in that: The invention comprises the resin material with high carbonization rate as described in any one of claims 1 to 3.

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