Preparation method and application of polyurethane-based hard carbon material
By preparing phosphorus-containing polyol polyurethane-based hard carbon materials, the energy density and first coulombic efficiency problems of existing hard carbon materials in battery anode applications have been solved, thus improving the performance of sodium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2026-04-14
AI Technical Summary
Existing hard carbon materials used as battery anodes suffer from low energy density, poor initial coulombic efficiency, and poor batch stability. In particular, when phenolic resin is carbonized and used as an anode material, sodium is easily released during charging and discharging, resulting in low battery cycle life. The microstructure of biomass materials and natural materials such as asphalt is difficult to control after carbonization.
Polyurethane-based hard carbon materials were prepared using phosphorus-containing polyols as reactants and then calcined at 900℃-1400℃ to form PC bonds, thereby increasing the interlayer spacing of the carbon layers. These materials were then used as negative electrode materials in sodium-ion batteries.
A polyurethane-based hard carbon material with high carbonization yield was developed, which improved the first coulombic efficiency, energy density, and cycle capacity retention of sodium-ion batteries, significantly enhancing battery performance.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of hard carbon materials technology, and particularly relates to a method for preparing polyurethane-based hard carbon materials and their applications. Background Technology
[0002] The rapid growth in sales of new energy vehicles is inseparable from the continuous development of battery material technology, including the efficient iteration and progress of materials such as cathodes, anodes, separators, and electrolytes. Regarding battery anode materials, the research community has developed four main categories: alloy materials, metal oxide and sulfide materials, organic materials, and carbon-based materials. Among carbon-based materials, amorphous carbon materials hold the greatest promise for commercialization.
[0003] Hard carbon is the most commonly used carbon-based material, generally produced by high-temperature calcination and carbonization of biomass materials (such as coconut shells, glucose, sucrose, cellulose, and lignin), asphalt, coal, and phenolic resin. However, when phenolic resin is carbonized and used as an anode material, it suffers from low energy density and poor initial coulombic efficiency. When applied to sodium-ion batteries, it easily leads to sodium deposition during charging and discharging, resulting in low battery cycle life. Carbonized natural materials such as biomass, asphalt, and coal, when used as anode materials, generally exhibit poor batch-to-batch stability and difficulty in controlling their microstructure.
[0004] Existing technologies rarely use polyurethane as a precursor to prepare hard carbon materials, and even more so, they neglect the excellent performance of polyurethane-based hard carbon when applied to battery anode materials. There is an urgent need in this field for the development and research of artificially synthesized resin-based hard carbon with high energy density and good first coulombic efficiency. Summary of the Invention
[0005] To address the aforementioned technical problems, the present invention aims to provide a method for preparing polyurethane-based hard carbon materials and their applications. By adding phosphorus-containing polyols to the formulation to prepare solid polyurethane materials and using them as negative electrode raw materials in the battery field, the hard carbon material can achieve excellent performance in battery first coulombic efficiency, energy density, and cycle capacity retention while maintaining a high carbonization yield. It is a new material with great potential for industry development.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] In the first aspect, a method for preparing a polyurethane-based hard carbon material is provided, comprising the following steps:
[0008] Solid polyurethane material is calcined and carbonized at 900℃-1400℃ (e.g., 950℃, 1000℃, 1100℃, 1200℃, 1300℃) and then post-treated to obtain powdered polyurethane-based hard carbon material.
[0009] The solid polyurethane material is a polyurethane product obtained by reacting reaction raw materials containing isocyanate, non-phosphorus polyol, and phosphorus polyol.
[0010] The steps for preparing the solid polyurethane material described herein can be standard practice in the art. By adjusting the raw materials and formulations used in preparing the solid polyurethane material, certain structures and properties of the solid polyurethane material can be controlled.
[0011] Phosphorus-containing polyols are a class of organic compounds that simultaneously contain phosphorus and multiple hydroxyl groups. According to the preparation method provided by the present invention, in some embodiments, the phosphorus content in the phosphorus-containing polyol is 8–18 wt% (e.g., 9 wt%, 10 wt%, 12 wt%, 13 wt%, 15 wt%, 17 wt%). The hydroxyl functionality in the phosphorus-containing polyol is 1–8, for example, 1, 2, 3, 4, 5, 6, or 7.
[0012] In some implementations, the phosphorus-containing polyol may be Clariant Exolit OP550.
[0013] In some embodiments, the amount of the phosphorus-containing polyol is 10 to 25 wt% of the amount of the non-phosphorus-containing polyol (e.g., 12 wt%, 14 wt%, 15 wt%, 16 wt%, 18 wt%, 20 wt%, 22 wt%, 24 wt%).
[0014] In some embodiments, the non-phosphorus polyol is selected from at least one of polyether polyols and polyester polyols.
[0015] The polyether polyol may be, for example, a vegetable oil-based polyether polyol with a molecular weight of 350-6000, or a petroleum-based polyether polyol with a molecular weight of 600-5000.
[0016] The polyester polyol may be, for example, a vegetable oil-based polyester polyol with a molecular weight of 600-4000, or a petroleum-based polyester polyol with a molecular weight of 600-8000.
[0017] In some embodiments, the isocyanate is selected from at least one of aliphatic diisocyanates with NCO functionality ≥2, aromatic diisocyanates and their derivatives, and polymethylene polyphenyl polyisocyanates.
[0018] In some embodiments, the amount of isocyanate used is 100-200 wt% of the amount of non-phosphorus polyol used, for example, 110 wt%, 120 wt%, 140 wt%, 150 wt%, 160 wt%, 180 wt%.
[0019] According to the preparation method provided by the present invention, in some embodiments, the reaction raw materials of the solid polyurethane material further include a catalyst.
[0020] In some embodiments, the catalyst is selected from amine catalysts and / or organometallic catalysts. In this document, amine catalysts and organometallic catalysts can be selected from commonly used catalyst types in the art, and are not limited herein.
[0021] In some embodiments, the catalyst is used in an amount of 1 to 5 wt% of the amount of the non-phosphorus polyol (e.g., 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%).
[0022] According to the preparation method provided by the present invention, in some embodiments, the reaction raw materials of the solid polyurethane material further include a chain extender.
[0023] In some embodiments, the chain extender is an alcoholic amine compound, preferably triethanolamine.
[0024] In some embodiments, the chain extender is used in an amount of 4 to 8 wt% of the amount of the non-phosphorus polyol (e.g., 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%).
[0025] In some embodiments, the solid polyurethane material is selected from block polyurethane, powdered polyurethane, or mixtures thereof.
[0026] In some implementations, the roasting and carbonization time is 1-4 hours (e.g., 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours).
[0027] The equipment used for roasting and carbonization can be a conventional choice in the field, such as a tube furnace or a box furnace.
[0028] According to the preparation method provided by the present invention, in some embodiments, the post-processing is to crush the product obtained after calcination and carbonization (using crushing equipment); the average particle size of the crushed powdered polyurethane-based hard carbon material is 5-10 micrometers (e.g., 6 micrometers, 8 micrometers, 9 micrometers).
[0029] The crushing equipment can be a conventional choice in the art, such as a crusher, ball mill, double roller mill, mechanical mill, air jet mill, or sand mill.
[0030] In the second aspect, an application of a polyurethane-based hard carbon material prepared by the method described above is provided in the fields of battery materials and porous carbon materials.
[0031] According to the application provided by the present invention, in some embodiments, the application includes preparing a sodium-ion battery using the polyurethane-based hard carbon material as a negative electrode raw material. The specific operating steps and process conditions for the application are conventional practices in the art and will not be elaborated here.
[0032] Compared with the prior art, the beneficial effects of the technical solution of the present invention are at least as follows:
[0033] (1) This invention uses solid polyurethane as a precursor to prepare hard carbon materials through carbonization, which expands the application field of polyurethane materials; at the same time, it also tailors a preparation scheme for polyurethane-based hard carbon materials, making them applicable in the field of battery materials; applying polyurethane-based hard carbon materials to battery anodes is a new type of hard carbon material with high carbonization yield, and sodium-ion batteries assembled from this anode have good first coulombic efficiency, energy density and other performance, and have great potential for industry development.
[0034] (2) Introducing phosphorus-containing polyols into the polyurethane crosslinking network backbone to form PC bonds, so that phosphorus elements are retained in the carbon layer body after carbonization; compared with the carbon layer spacing of pure carbon materials (e.g. 0.3386~0.3393nm), the carbon layer spacing of hard carbon obtained after introducing phosphorus elements is increased (e.g. 0.3836~0.3886nm), the number of active sites increases, the barrier for sodium ion insertion into the carbon layer is greatly reduced, the sodium storage performance of carbon materials is greatly improved, which is conducive to improving the reversible capacity and first coulombic efficiency of sodium-ion batteries. Attached Figure Description
[0035] Figure 1 A schematic photograph is shown of the polyurethane prepared by adding phosphorus-containing polyol in Example 1 before carbonization.
[0036] Figure 2 A schematic photograph is shown of the polyurethane prepared by adding phosphorus-containing polyol in Example 1 after carbonization.
[0037] Figure 3 The infrared spectrum of the polyurethane prepared by adding phosphorus-containing polyol in Example 1 is shown.
[0038] Figure 4 The infrared spectrum of the polyurethane prepared in Comparative Example 3 without the addition of phosphorus-containing polyols is shown. Detailed Implementation
[0039] To provide a detailed understanding of the technical features and content of this invention, preferred embodiments will be described in more detail below. While preferred embodiments are described in the examples, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.
[0040] Main raw material information:
[0041] Polyether polyols: R2403, Wanhua Chemical;
[0042] Polyester polyols: WHP-H6, Wanhua Chemical;
[0043] Phosphorus-containing polyols: Exolit OP550, Clariant;
[0044] Isocyanates: PM-700, Wanhua Chemical;
[0045] Additive-1: SP703 (catalyst), Wanhua Chemical;
[0046] Additive-2: 1104 (chain extender), Wanhua Chemical.
[0047] Example 1
[0048] A method for preparing polyurethane-based hard carbon material #1 includes the following steps:
[0049] (1) Polyether polyol, phosphorus-containing polyol, isocyanate, additive-1 and additive-2 are kept at 22°C for 3 hours, and then mixed in a mass ratio of 85:15:150:2:5. The mixture is stirred rapidly at a stirring speed of 3000rpm for 7s. After natural cooling, solid polyurethane material is obtained.
[0050] The changes in functional groups of the prepared solid polyurethane material after the addition of phosphorus-containing polyols were characterized using Fourier transform infrared spectroscopy (FTIR). Specifically, the solid polyurethane material sample to be tested was cut into 20×20×1mm pieces. 3 Thin slices were subjected to diffuse reflectance Fourier transform infrared spectroscopy, with a scanning range of 4000-400 cm⁻¹. -1 The test results are shown below. Figure 3 ;
[0051] (2) The solid polyurethane material obtained in step (1) is initially crushed to 100-200 micrometers in a crusher (WH101X, Wheatstone), and then placed in a box furnace (SG-XL, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences) for carbonization at a temperature of 1100℃ for 2 hours to obtain carbonized material.
[0052] (3) The carbonized material obtained in step (2) is crushed in an air jet mill to an average particle size of 5-10 micrometers to obtain polyurethane-based hard carbon material 1#.
[0053] Example 2
[0054] The process for preparing polyurethane-based hard carbon material 2# is the same as in Example 1, except that in step (1), the mass ratio of polyether polyol, phosphorus-containing polyol, isocyanate, additive-1, and additive-2 is 80:20:150:2:5, and in step (2), the carbonization temperature is 900℃ and the carbonization time is 4 hours; the remaining steps are the same as in Example 1, and polyurethane-based hard carbon material 2# is obtained.
[0055] Example 3
[0056] The process for preparing polyurethane-based hard carbon material 3# is the same as in Example 1, except that in step (1), the mass ratio of polyether polyol, phosphorus-containing polyol, isocyanate, additive-1, and additive-2 is 91:9:150:2:5, and in step (2), the carbonization temperature is 1400℃ and the carbonization time is 1 hour; the remaining steps are the same as in Example 1, and polyurethane-based hard carbon material 3# is obtained.
[0057] Example 4
[0058] The method for preparing polyurethane-based hard carbon material #4 is the same as in Example 1, except that in step (1), the polyether polyol is used. R2403 was replaced with polyester polyol. WHP-H6; the remaining steps are the same as in Example 1, to obtain polyurethane-based hard carbon material 4#.
[0059] Comparative Example 1
[0060] A method for preparing phenolic resin-based hard carbon material 1'# includes the following steps:
[0061] (1) The purchased liquid phenolic resin (brand name PF-2550, Shandong Shengquan) was directly cured at 120℃ for 3 hours to obtain solid phenolic resin material.
[0062] (2) The operation of carbonizing the solid phenolic resin material obtained in step (1) is the same as step (2) in Example 1;
[0063] (3) The operation of crushing the carbonized material obtained in step (2) is the same as step (3) in Example 1; to obtain phenolic resin-based hard carbon material 1'#.
[0064] Comparative Example 2
[0065] A method for preparing biomass-based hard carbon material 2'# includes the following steps:
[0066] (1) Directly use the pre-carbonized coconut shell material (brand name YTL-IDA, Shenzhen Yituolian) obtained from procurement as a solid biomass-based material;
[0067] (2) The operation of carbonizing the solid biomass-based material obtained in step (1) is the same as step (2) in Example 1;
[0068] (3) The operation of crushing the carbonized material obtained in step (2) is the same as step (3) in Example 1; to obtain biomass-based hard carbon material 2'#.
[0069] Comparative Example 3
[0070] The process for preparing polyurethane-based hard carbon material 3'# is the same as in Example 1, except that phosphorus-containing polyols are not added in step (1), and the mass ratio of polyether polyol, isocyanate, additive-1, and additive-2 is 100:150:2:5; the FTIR test results of the sample obtained in step (1) are shown in [reference needed]. Figure 4 ;
[0071] The remaining steps are the same as in Example 1, and polyurethane-based hard carbon material 3'# is obtained.
[0072] Comparative Example 4
[0073] The process for preparing polyurethane-based hard carbon material 4'# is the same as in Example 1, except that the amount of phosphorus-containing polyol used in step (1) is 6 wt% of the amount of polyether polyol used; the remaining steps are the same as in Example 1, and polyurethane-based hard carbon material 4'# is obtained.
[0074] The properties of the hard carbon materials prepared in each embodiment and comparative example are tested as follows:
[0075] 1. Carbonization yield test:
[0076] The mass of the precursor sample before carbonization is denoted as m1, and the mass of the carbonized material after carbonization is denoted as m2. The carbonization yield (wt%) is calculated as m2 / m1 × 100%. The test results are shown in Table 1.
[0077] 2. Carbon interlayer spacing test: The test samples were tested in accordance with Appendix E of GB / T 24533-2019; the test results are shown in Table 1.
[0078] 3. Battery assembly and performance testing:
[0079] Using a sodium metal sheet as the counter electrode; the hard carbon material, binder (carboxymethyl cellulose), conductive agent (Super P), and solvent (water) prepared as described in the above embodiments and comparative examples are mixed and stirred to form a slurry (wherein, the percentage content of binder, conductive agent, and hard carbon material is 10wt%, 10wt%, and 80wt%, respectively). The resulting slurry is then coated onto a copper foil, and after drying and rolling, a negative electrode sheet is obtained.
[0080] A coin cell (CR2430 type) was assembled in an argon-protected glove box using positive electrode plates, negative electrode plates, and electrolyte. The electrolyte was a 1M NaPF6 solution dissolved in a mixture of ethylene carbonate and dimethyl carbonate (volume ratio 1:1). The assembled cell was charged and discharged at a current density of 0.1C for two cycles at a voltage of 0-1.5V. The reversible capacity, initial coulombic efficiency (during discharge), and cycle capacity retention were then measured after 500 cycles at 0.1C. The test results are shown in Table 1.
[0081] Table 1. Test results of the products obtained from each embodiment and comparative example.
[0082]
[0083] pass Figure 3 , Figure 4 It can be seen that, with Figure 4 Compared to polyurethane materials prepared without the addition of phosphorus-containing polyols, Figure 3 The polyurethane material prepared by adding phosphorus-containing polyols shown in the figure has newly formed PC bonds (731 cm). -1 The displacement indicates that phosphorus has reacted and entered the cross-linked network framework of the polyurethane. This increases the interlayer spacing of the carbon layers in the resulting hard carbon material (0.3870–0.3886 nm), increases the number of active sites, and significantly reduces the barrier for sodium ion insertion into the carbon layers. This greatly improves the sodium storage performance of the carbon material, which is beneficial for enhancing the reversible capacity and initial coulombic efficiency of the battery. In other words, the hard carbon material prepared by the technical solution of this invention has significantly improved sodium storage performance, thereby improving the reversible capacity (energy density), initial coulombic efficiency, and cycle capacity retention of the battery, while also maintaining a high carbonization yield.
[0084] Compared with phenolic resin-based hard carbon materials (Comparative Example 1) and biomass-based hard carbon materials (Comparative Example 2), polyurethane-based hard carbon materials (Example 1) have a significantly higher carbonization yield. When used to prepare sodium-ion battery anodes, the resulting batteries outperform phenolic resin-based hard carbon materials and biomass-based hard carbon materials in terms of reversible capacity and cycle capacity retention. They also have a slightly better first coulombic efficiency than phenolic resin-based hard carbon materials and biomass-based hard carbon materials.
[0085] Figure 1 This diagram shows the polyurethane prepared by adding phosphorus-containing polyol in Example 1 before carbonization. Figure 2The diagram illustrates the carbonized polyurethane prepared by adding phosphorus-containing polyols in Example 1. Compared to the blank sample (Comparative Example 3, the sample without added phosphorus-containing polyols), the addition of phosphorus-containing polyols in Examples 1-4 introduced phosphorus into the polyurethane-based hard carbon material, increasing the carbon interlayer spacing by nearly 10%. This is significant for improving the sodium storage performance of the sodium-ion battery anode, thereby enhancing the battery's reversible capacity and first coulombic effect.
[0086] Although phosphorus-containing polyols were added during the preparation of polyurethane in Comparative Example 4, the amount used was not controlled within an appropriate range, which also affected the effect of increasing the carbon interlayer spacing, resulting in poor performance improvement of the battery.
[0087] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the spirit of the invention.
Claims
1. A method for preparing a polyurethane-based hard carbon material, characterized in that, Includes the following steps: Solid polyurethane material is calcined and carbonized at 900℃-1400℃ and then post-treated to obtain powdered polyurethane-based hard carbon material. The solid polyurethane material is a polyurethane product obtained by reacting reaction raw materials containing isocyanate, non-phosphorus polyol, and phosphorus polyol.
2. The preparation method according to claim 1, characterized in that, The phosphorus content in the phosphorus-containing polyol is 8-18 wt%. The amount of phosphorus-containing polyol used is 10-25 wt% of the amount of non-phosphorus-containing polyol used.
3. The preparation method according to claim 1 or 2, characterized in that, The non-phosphorus-containing polyol is selected from at least one of polyether polyol and polyester polyol; The isocyanate is selected from at least one of aliphatic diisocyanates with NCO functionality ≥2, aromatic diisocyanates and their derivatives, and polymethylene polyphenyl polyisocyanates. The amount of isocyanate used is 100-200 wt% of the amount of non-phosphorus polyol used.
4. The preparation method according to any one of claims 1-3, characterized in that, The reaction raw materials for the solid polyurethane material also include a catalyst; The catalyst is selected from amine catalysts and / or organometallic catalysts; The amount of catalyst used is 1 to 5 wt% of the amount of non-phosphorus polyol used.
5. The preparation method according to any one of claims 1-4, characterized in that, The reaction raw materials for the solid polyurethane material also include chain extenders; The chain extender is an alcoholic amine compound, preferably triethanolamine; The amount of the chain extender is 4-8 wt% of the amount of the non-phosphorus polyol.
6. The preparation method according to any one of claims 1-5, characterized in that, The solid polyurethane material is selected from block polyurethane, powdered polyurethane, or mixtures thereof.
7. The preparation method according to any one of claims 1-6, characterized in that, The roasting and carbonization time is 1-4 hours.
8. The preparation method according to any one of claims 1-7, characterized in that, The post-processing involves crushing the product obtained after calcination and carbonization; the average particle size of the crushed polyurethane-based hard carbon material is 5-10 micrometers.
9. The application of the polyurethane-based hard carbon material prepared by any one of claims 1-8 in the fields of battery materials and porous carbon materials.
10. The application according to claim 9, characterized in that, This includes using the polyurethane-based hard carbon material as a negative electrode material to prepare sodium-ion batteries.