Hard carbon material, preparation method thereof and sodium ion battery
A high-efficiency hard carbon material was prepared by a three-stage sintering process using biomass materials and sorbic acid-modified composites. This solved the problems of low efficiency and low capacity of sodium-ion battery anode materials, and enabled sodium-ion batteries with high capacity and good cycle performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUIZHOU WEIFANG ENERGY NEW MATERIAL TECH CO LTD
- Filing Date
- 2024-04-01
- Publication Date
- 2026-05-29
AI Technical Summary
The existing anode material for sodium-ion batteries, hard carbon, suffers from low initial coulombic efficiency and low specific capacity, making it difficult to meet the requirements for commercial applications.
Using biomass materials as raw materials, hard carbon materials are prepared through three sintering processes and sorbic acid modification, forming a carbon coating layer with a microporous polyacrylic acid structure, thereby improving the electrochemical performance of the materials.
The prepared hard carbon material exhibits excellent initial coulombic efficiency and cycling performance, with a capacity as high as 354.34 mAh/g and a capacity retention of 90.63% after 200 cycles.
Smart Images
Figure CN118183700B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery materials technology, and in particular to a hard carbon material, its preparation method, and a sodium-ion battery. Background Technology
[0002] With the widespread application of electric vehicles and various electronic appliances, the energy storage lithium-ion batteries used in them have also developed rapidly. However, the excessive demand for lithium resources has highlighted supply bottlenecks, and the uneven distribution of lithium resources has limited the further development of lithium-ion batteries. Therefore, new energy storage devices have been gradually developed. Among them, sodium-ion batteries, due to their sodium element being in the same group as lithium and having similar chemical properties, coupled with the abundance of sodium on Earth, its wide distribution, and ease of extraction, have made sodium-ion batteries the best alternative to lithium-ion batteries.
[0003] While sodium-ion batteries offer advantages such as low cost and high safety, developing batteries with higher specific capacity and better electrochemical performance remains a pressing issue. In sodium-ion batteries, the anode material is crucial for their application in energy storage systems. Hard carbon materials, with their larger interlayer spacing than graphite, facilitate the storage and intercalation / deintercalation of sodium ions, maintaining good stability during this process, making them suitable as anode materials for sodium-ion batteries. However, they still face challenges such as low initial coulombic efficiency and low specific capacity, hindering the commercialization of sodium-ion batteries. Summary of the Invention
[0004] Based on this, the purpose of this application is to provide a hard carbon material, its preparation method, and a sodium-ion battery. By using sorbic acid for modification and composite, a low-cost, high-capacity sodium-ion battery anode material is prepared, providing a new approach and effective measure for the large-scale production of sodium-ion batteries in the energy storage field.
[0005] To achieve the above objectives, the technical solution of this application is as follows:
[0006] This application provides a method for preparing hard carbon material, including:
[0007] The biomass material is first sintered and pulverized to obtain the first precursor.
[0008] The first precursor is subjected to a second sintering to obtain a second precursor;
[0009] The second precursor was mixed with sorbic acid to obtain the third precursor;
[0010] The third precursor is subjected to a third sintering process to obtain the hard carbon material.
[0011] Preferably, the biomass material includes at least one of potato starch, cork, corn starch, mung bean starch, coconut shell, peanut shell, lignin, and sawdust.
[0012] Preferably, the first sintering includes: raising the temperature to 180℃-260℃ in an air atmosphere and holding it at that temperature for 2h-24h.
[0013] Preferably, the second sintering includes: raising the temperature to 500℃-900℃ in a protective gas atmosphere and holding it at that temperature for 1h-6h.
[0014] More preferably, the protective gas includes at least one of nitrogen, argon, helium, and neon.
[0015] Preferably, the mixing of the second precursor with sorbic acid includes: dissolving the sorbic acid in ethanol, then adding the second precursor and ultrasonically stirring and dispersing for 2-48 hours, filtering, and drying at a temperature of 60℃-120℃.
[0016] Preferably, the third sintering includes: raising the temperature to 800℃-1500℃ in a protective gas atmosphere and holding it at that temperature for 4h-20h.
[0017] Preferably, after pulverization, the first precursor obtained has a mesh size of 80-2000 mesh.
[0018] This application provides a hard carbon material, which is prepared using the above-described method for preparing hard carbon materials.
[0019] This application also provides a sodium-ion battery comprising the aforementioned hard carbon material.
[0020] The beneficial effects of this application are:
[0021] In the preparation method of hard carbon material of this application, sorbic acid is used as a raw material for modification and composite by biomass material, followed by three sintering processes to prepare sorbic acid-modified hard carbon material. This preparation method is simple to operate, has almost no environmental pollution, and can be carried out on a large scale.
[0022] The hard carbon material of this application can be used as a negative electrode material for sodium-ion batteries, exhibiting good initial coulombic efficiency and cycle performance.
[0023] The sodium-ion battery of this application uses the aforementioned hard carbon material as the negative electrode, achieving a capacity of up to 354.34 mAh / g, an initial efficiency of 89.00%, and a capacity retention rate of up to 90.63% after 200 cycles at room temperature of 0.2C (1C = 300 mAh / g). Attached Figure Description
[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.
[0025] Figure 1 The image shows the performance of the hard carbon anode material prepared in Example 1 after 200 cycles.
[0026] Figure 2 The diagram shows the first-cycle charge-discharge performance of the hard carbon anode material prepared in Example 1. Detailed Implementation
[0027] As used in this article:
[0028] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus. The conjunction "composed of" excludes any unnamed elements, steps, or components.
[0029] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.
[0030] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.
[0031] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.
[0032] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).
[0033] This application provides a method for preparing hard carbon material, including:
[0034] S1. The biomass material is first sintered and pulverized to obtain the first precursor;
[0035] S2. The first precursor is subjected to a second sintering to obtain a second precursor;
[0036] S3. Mix the second precursor with sorbic acid to obtain the third precursor;
[0037] S4. The third precursor is subjected to a third sintering to obtain the hard carbon material.
[0038] In one embodiment of this application, the biomass material in S1 includes at least one of potato starch, cork, corn starch, mung bean starch, coconut shell, peanut shell, lignin, and sawdust.
[0039] In one embodiment of this application, the first sintering in S1 includes: raising the temperature to 180°C-260°C in an air atmosphere; typically, but not limitingly, the first sintering temperature can be, for example, 180°C, 200°C, 220°C, 240°C, 260°C, or any value between 180°C and 260°C; holding at this temperature for 2 hours to 24 hours; typically, but not limitingly, the first sintering time can be, for example, 2 hours, 6 hours, 10 hours, 12 hours, 18 hours, 24 hours, or any value between 2 hours and 24 hours. Preferably, the first sintering temperature in S1 is 220°C-240°C, and the sintering time is 4 hours to 6 hours.
[0040] In one embodiment of this application, the second sintering in step S2 includes: raising the temperature to 500°C-900°C in a protective gas atmosphere; typically, but not limitingly, the second sintering temperature can be, for example, 500°C, 600°C, 700°C, 800°C, 900°C, or any value between 500°C and 900°C; holding at this temperature for 1 hour to 6 hours; typically, but not limitingly, the second sintering time can be, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or any value between 1 hour and 6 hours. Preferably, the second sintering temperature in step S2 is 500°C-510°C, and the sintering time is 1 hour to 2 hours.
[0041] More preferably, the protective gas includes at least one of nitrogen, argon, helium, and neon.
[0042] It should be noted that the primary purpose of this application in performing a first sintering of the biomass material under an oxygen-containing atmosphere is to introduce oxygen molecules into the material, allowing them to fully react and form oxygen-containing functional groups as active sites. Simultaneously, some oxygen reacts with some carbon to generate CO and CO2, creating pores on the material's surface and interior. These pores facilitate the storage of sodium ions, thereby improving the material's electrochemical performance. The sintering and carbonization of the first precursor in this application removes tar from the first precursor, preventing subsequent tar from affecting the performance of the resulting hard carbon material.
[0043] In one embodiment of this application, mixing the second precursor with sorbic acid in S3 includes: dissolving sorbic acid in ethanol, adding the second precursor to the solution, ultrasonically stirring and dispersing for 2-48 hours, filtering, and then drying at 60°C-120°C to obtain the third precursor. Typically, but not limitingly, the ultrasonic stirring time can be 2 hours, 10 hours, 20 hours, 30 hours, 40 hours, 48 hours, or any combination thereof. More preferably, the ultrasonic stirring time is 4-8 hours.
[0044] In one embodiment of this application, the third sintering in S4 includes: raising the temperature to 800°C-1500°C in a protective gas atmosphere; typically, but not limitingly, the temperature of the third sintering can be, for example, 800°C, 1000°C, 1200°C, 1400°C, 1500°C, or any value between 800°C and 1500°C; holding at this temperature for 4 hours to 20 hours; typically, but not limitingly, the time of the third sintering can be, for example, 4 hours, 8 hours, 12 hours, 16 hours, 20 hours, or any value between 4 hours and 20 hours. Preferably, the temperature of the third sintering is 1300°C-1350°C, and the carbonization time is 14 hours to 16 hours.
[0045] Understandably, mixing the second precursor with an organic acid solution like sorbic acid allows the organic acid to effectively penetrate the porous structure of the second precursor. The modification principle using organic acids is as follows: the introduction of the two -COOH groups in the organic acid promotes the C+O=CO / CO2 reaction, thereby promoting micropore formation. This reacts with the CH groups and impurity groups on the hard carbon surface, forming a carbon coating layer with a polyacrylic acid microporous structure. This coating has an activating effect, preventing direct contact between the electrolyte and the hard carbon material itself, thus improving initial coulombic efficiency and cycle stability, and preventing structural damage. It should also be noted that the carbon chain of the organic acid used should not be too long; excessively long carbon chains will affect the oxygen content of the organic acid, thereby reducing micropore formation.
[0046] The modified third precursor is sintered and carbonized to further maintain the structural stability of the hard carbon material in order to obtain higher capacity and first coulomb efficiency.
[0047] In some embodiments of this application, the solvent required to dissolve sorbic acid in S3 includes at least one of water, ethanol, propanol, diethyl ether, ethyl acetate, glycerol, and acetone; the concentration of the solution after sorbic acid dissolution is 0.05 mol / L to 5 mol / L; typically, but not limitingly, the solution concentration can be 0.05 mol / L, 0.5 mol / L, 1 mol / L, 3 mol / L, 5 mol / L, or any combination thereof, and more preferably 1 mol / L to 1.5 mol / L.
[0048] In one embodiment of this application, after pulverization in S1, the first precursor is sieved to obtain a mesh size of 80-2000 mesh. Preferably, the first precursor is sieved through a 300-600 mesh screen.
[0049] In some embodiments of this application, a hard carbon material is also provided, which is prepared by the above-described method for preparing hard carbon materials.
[0050] The hard carbon material of this application is modified with organic acid. The coating layer on the surface of the hard carbon material effectively reduces the specific surface area of the HC material, thereby shortening the migration distance of sodium ions and making the deintercalation and intercalation of sodium ions more efficient.
[0051] Some embodiments of this application also provide a sodium-ion battery comprising the aforementioned hard carbon material.
[0052] The hard carbon material prepared by the method of this application can be used as a negative electrode material for sodium-ion batteries, which is beneficial to improving the capacity, initial coulombic efficiency and cycle performance of sodium-ion batteries; the specific capacity of the battery can reach more than 354.34 mAh / g, and the capacity retention rate after 200 cycles can reach 90.63%, thus improving the performance of the battery.
[0053] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.
[0054] Example 1
[0055] This embodiment provides a hard carbon material, the preparation method of which includes:
[0056] (1) Potato starch is first sintered in air (sintering temperature is 220℃, heat preservation for 6h), and then crushed and sieved to obtain porous particles, which are the first precursors.
[0057] (2) The first precursor was subjected to a second sintering under nitrogen protection (sintering temperature of 500℃, holding for 2h) to obtain a black powder, which is the second precursor.
[0058] (3) The second precursor was added to a sorbic acid-ethanol mixed solution, ultrasonically dispersed for 4 hours, then filtered and dried at 100°C to obtain the third precursor.
[0059] (4) The third precursor is subjected to a third sintering under nitrogen protection (sintering temperature is 1350℃, holding time is 14h) to obtain hard carbon material.
[0060] Example 2
[0061] This embodiment provides a hard carbon material, the preparation method of which includes:
[0062] (1) The cork is sintered in air for the first time (sintering temperature is 200℃, heat preservation for 20h), and then crushed and sieved to obtain porous particles, which are the first precursors.
[0063] (2) The first precursor was subjected to a second sintering under nitrogen protection (sintering temperature of 600℃, holding for 3h) to obtain a black powder, which is the second precursor.
[0064] (3) The second precursor was added to a sorbic acid-ethanol mixed solution, ultrasonically dispersed for 5 hours, then filtered and dried at 100°C to obtain the third precursor.
[0065] (4) The third precursor is subjected to a third sintering under nitrogen protection (sintering temperature is 800℃, holding time is 20h) to obtain hard carbon material.
[0066] Example 3
[0067] This embodiment provides a hard carbon material, the preparation method of which includes:
[0068] (1) The coconut shell is sintered in air for the first time (sintering temperature is 260℃, heat preservation for 12h), and then crushed and sieved to obtain porous particles, which are the first precursors.
[0069] (2) The first precursor was subjected to a second sintering under nitrogen protection (sintering temperature of 900℃, holding for 1h) to obtain a black powder, which is the second precursor.
[0070] (3) The second precursor was added to a sorbic acid-ethanol mixed solution, ultrasonically dispersed for 8 hours, then filtered and dried at 100°C to obtain the third precursor.
[0071] (4) The third precursor is subjected to a third sintering under nitrogen protection (sintering temperature is 1500℃, holding time is 10h) to obtain hard carbon material.
[0072] Comparative Example 1
[0073] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 1. The difference is that the second precursor material in step (3) is directly subjected to a third sintering under nitrogen protection (sintering temperature is 800℃, holding for 4h) to obtain the hard carbon material, without the addition of sorbic acid for modification.
[0074] Comparative Example 2
[0075] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 2. The difference is that the second precursor material in step (3) is directly subjected to a third sintering under nitrogen protection (sintering temperature is 1200℃, holding for 20h) to obtain the hard carbon material, without the addition of sorbic acid for modification.
[0076] Comparative Example 3
[0077] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 1. The difference is that the second precursor material in step (3) is added to D-malic acid ethanol solution for modification treatment, ultrasonically dispersed, filtered and dried to obtain the third precursor, and then step (4) is carried out.
[0078] Comparative Example 4
[0079] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 2. The difference is that the second precursor material in step (3) is added to D-malic acid ethanol solution for modification treatment, ultrasonically dispersed, filtered and dried to obtain the third precursor, and then step (4) is carried out.
[0080] Comparative Example 5
[0081] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 1. The difference is that the second precursor material in step (3) is added to a tannic acid aqueous solution for modification treatment, ultrasonically dispersed, filtered and dried to obtain the third precursor, and then step (4) is carried out.
[0082] Comparative Example 6
[0083] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 2. The difference is that the second precursor material in step (3) is added to a tannic acid aqueous solution for modification treatment, ultrasonically dispersed, filtered and dried to obtain the third precursor, and then step (4) is carried out.
[0084] Comparative Example 7
[0085] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 1. The difference is that the second precursor material in step (3) is added to an acetic acid solution for modification treatment, ultrasonically dispersed, filtered and dried to obtain the third precursor, and then step (4) is carried out.
[0086] Comparative Example 8
[0087] This comparative example provides a hard carbon material, which is prepared in the same way as in Example 1. The difference is that the second precursor material in step (3) is added to an oxalic acid solution for modification treatment, ultrasonically dispersed, filtered and dried to obtain the third precursor, and then step (4) is carried out.
[0088] The hard carbon materials prepared in the above embodiments and comparative examples were used as negative electrode active materials to form negative electrode sheets, and sodium sheets were used as positive electrode sheets to assemble coin cells. Charge-discharge cycle tests were conducted at 20℃-25℃, within a voltage range of 0.01V-2V, and at a current density of 0.2C (1C=300mAh / g), and the test results are shown in Table 1. Figure 1 and Figure 2 Performance graphs of the coin cell assembled with the hard carbon anode material in Example 1 after 200 cycles and the first charge-discharge performance graph are given respectively.
[0089] Table 1 Test results for each embodiment and comparative example
[0090]
[0091] As shown in Table 1, the electrochemical performance of the hard carbon materials obtained by modifying the second precursor with other organic acids (such as D-malic acid, tannic acid, oxalic acid, acetic acid, etc.) is not as good as that of the hard carbon materials obtained by modifying with sorbic acid.
[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
[0093] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the embodiments claimed above can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
Claims
1. A method for preparing a hard carbon material, characterized in that, include: The biomass material is first sintered and pulverized to obtain the first precursor. The first precursor is subjected to a second sintering to obtain a second precursor; The second precursor was mixed with sorbic acid to obtain the third precursor; The third precursor is subjected to a third sintering to obtain the hard carbon material; The biomass material includes at least one of potato starch, cork, corn starch, mung bean starch, coconut shell, peanut shell, lignin, and sawdust. The first sintering includes: raising the temperature to 180℃-260℃ in an air atmosphere and holding it at that temperature for 2h-24h; The second sintering process includes: raising the temperature to 500℃-900℃ in a protective gas atmosphere and holding it at that temperature for 1h-6h; The third sintering process includes: raising the temperature to 800℃-1500℃ in a protective gas atmosphere and holding it at that temperature for 4h-20h.
2. The method for preparing hard carbon material as described in claim 1, characterized in that, The protective gas includes at least one of nitrogen, argon, helium, and neon.
3. The method for preparing hard carbon material as described in claim 1, characterized in that, The mixing of the second precursor with sorbic acid includes: dissolving the sorbic acid in ethanol, then adding the second precursor and ultrasonically stirring and dispersing for 2-48 hours, filtering, and drying at a temperature of 60℃-120℃.
4. The method for preparing hard carbon material according to any one of claims 1-3, characterized in that, After pulverization, the first precursor obtained has a mesh size of 80-2000 mesh.
5. A hard carbon material, characterized in that, It is prepared by the method for preparing hard carbon material according to any one of claims 1-4.
6. A sodium-ion battery, characterized in that, Includes the hard carbon material as described in claim 5.