Method for preparing sodium-ion battery hard carbon negative electrode material from sulfur-doped modified bamboo-based biomass and application of sodium-ion battery hard carbon negative electrode material
By preparing hard carbon anode materials for sodium-ion batteries through sulfur-doped modification of bamboo-based biomass, the problems of uneven microstructure and poor electrochemical performance in existing technologies have been solved, achieving high-efficiency electrochemical performance and stable cycle performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF CHEM IND OF FOREST PROD CHINESE ACAD OF FORESTRY
- Filing Date
- 2025-12-11
- Publication Date
- 2026-05-01
AI Technical Summary
Existing biomass hard carbon materials in sodium-ion batteries suffer from problems such as uneven microstructure, low conductivity, difficulty in sodium ion intercalation, poor cycle stability, and differences in electrochemical reaction rates, resulting in low reversible capacity and poor rate performance.
A method for preparing hard carbon anode materials for sodium-ion batteries using sulfur-doped modified bamboo-based biomass includes steps such as pulverization, drying, mixing, low-temperature carbonization, and high-temperature carbonization. By controlling parameters such as powder particle size, type and proportion of sulfur source, and carbonization temperature, hard carbon materials with excellent electrochemical performance are prepared.
High specific energy and energy density of bamboo-based biomass hard carbon materials were achieved, with good electrochemical performance, an initial coulombic efficiency of about 65%, an initial discharge specific capacity of over 350 mAh/g, and stable cycle performance.
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Figure CN121948416A_ABST
Abstract
Description
A method and application for preparing hard carbon anode materials for sodium-ion batteries using sulfur-doped modified bamboo-based biomass. Technical Field
[0001] This invention belongs to the field of sodium-ion battery anode material preparation technology, specifically relating to a method and application for preparing hard carbon anode materials for sodium-ion batteries using sulfur-doped modified bamboo-based biomass. Background Technology
[0002] Sodium-ion batteries are particularly suitable for energy storage scenarios that do not require high energy density but need to be deployed on a large scale due to their abundant resources, low cost and high safety. They have good development prospects in the field of stationary energy storage.
[0003] Because sodium ions have a larger ionic radius than lithium ions, graphite anode materials, widely used in lithium-ion batteries, are difficult to apply in sodium-ion batteries. Hard carbon, with its high reversible specific capacity, excellent cycle performance, and low sodium storage potential, is currently the best choice for anode materials in the commercial application of sodium-ion batteries and is expected to be the first to be industrialized.
[0004] Compared to resin-based and petroleum-based precursors, biomass-based precursors are lower in cost, offering a significant cost advantage. Furthermore, biomass materials are renewable, abundant, inexpensive, and environmentally friendly. China boasts some of the world's largest bamboo reserves, which are widely distributed. Bamboo processing is relatively simple, significantly reducing the cost of hard carbon anode materials. Moreover, bamboo-based biomass hard carbon exhibits high specific energy and energy density.
[0005] However, the application of biomass hard carbon in sodium-ion batteries currently suffers from problems such as uneven microstructure, low conductivity, difficulty in sodium ion intercalation, poor cycle stability, and differences in electrochemical reaction rates between the surface and bulk phases, resulting in low reversible capacity and poor rate performance of the battery. Summary of the Invention
[0006] The first technical problem to be solved by this invention is to provide a method for preparing hard carbon anode materials for sodium-ion batteries using sulfur-doped modified bamboo-based biomass. This method is simple, environmentally friendly, and the prepared hard carbon has good electrochemical performance and low cost, enabling the high-value utilization of bamboo processing residues. The second technical problem to be solved by this invention is to provide a method for preparing hard carbon anode materials for sodium-ion batteries using sulfur-doped modified bamboo-based biomass, which has good electrochemical performance. The third technical problem to be solved by this invention is to provide the application of this hard carbon anode material for sodium-ion batteries in sodium-ion battery anodes.
[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0008] A method for preparing hard carbon anode materials for sodium-ion batteries from sulfur-doped modified bamboo-based biomass includes the following steps:
[0009] 1) The bamboo processing residue was crushed into powder and dried to constant weight to obtain the first precursor;
[0010] 2) The first precursor obtained in step 1) is mixed and impregnated with a sulfur source, filtered, and dried to obtain the second precursor;
[0011] 3) The second precursor obtained in step 2) is placed in a muffle furnace and carbonized at low temperature in an air atmosphere. After cooling, the third precursor is obtained.
[0012] 4) Grind the third precursor obtained in step 3) and then sieve it;
[0013] 5) The third precursor powder after sieving in step 4) is subjected to high-temperature carbonization in an inert atmosphere to obtain hard carbon material;
[0014] 6) The hard carbon material obtained in step 5) is washed with a solution, filtered, and dried to obtain sulfur-doped modified biomass bamboo-based hard carbon material.
[0015] Furthermore, in step 1), the particle size of the pulverized powder is 50~320 mesh.
[0016] Furthermore, in step 2), the sulfur source is selected from one or more of thiourea, sublimed urea, and anhydrous sodium sulfite.
[0017] Furthermore, in step 2), the mass ratio of the first precursor to the sulfur source is 1:0.2~0.5.
[0018] Furthermore, in step 3), the heating rate for medium-low temperature pre-carbonization is 3~5 ℃ / min, the temperature is 250~400 ℃, and the holding time is 1~2 h.
[0019] Furthermore, in step 4), the rotational speed of the ball mill is 800~1200 r / min, and the ball milling time is 1~5 min.
[0020] Further, in step 5), the inert gas is nitrogen or argon; the heating rate for high-temperature carbonization is 3~5 ℃ / min, the high-temperature carbonization temperature is 1000~1600 ℃, and the holding time is 2 h.
[0021] Further, in step 6), the washing solution is a 0.1 mol / L HCl aqueous solution. The solution is boiled for washing, then washed with distilled water until neutral, and dried in an oven at 80 °C for 12 h until constant weight.
[0022] Furthermore, the sodium-ion battery hard carbon anode material prepared by the sulfur-doped modified bamboo-based biomass method is described above.
[0023] Furthermore, the application of the aforementioned hard carbon anode material for sodium-ion batteries in the anode of sodium-ion batteries.
[0024] Compared with the prior art, the present invention has the following advantages:
[0025] (1) The raw materials required by this invention are widely distributed, easy to obtain, and have outstanding sustainability advantages such as renewability.
[0026] (2) In this invention, S has a large covalent radius, which can significantly expand the carbon interlayer spacing, which is beneficial for the insertion, extraction and diffusion of sodium ions. At the same time, the addition of active CS bonds provides additional sulfur-based redox active sites.
[0027] (3) Compared with the prior art, the bamboo-based biomass hard carbon material of the present invention has good electrochemical performance. When used as the negative electrode of sodium-ion battery and assembled into a button half cell, it has an initial coulombic efficiency of about 65% and a reversible specific capacity of more than 350 mAh / g. Attached Figure Description
[0028] Figure 1 shows TEM images of Embodiment 1 and Comparative Example 1 of this application; wherein, Figure a is a TEM image of Comparative Example 1 and Figure b is a TEM image of Embodiment 1.
[0029] Figure 2 shows the XRD patterns of Comparative Example 1 and Examples 1, 3, and 4 of this application;
[0030] Figure 3 shows the first-cycle charge-discharge performance of the hard carbon anode materials prepared in Examples 1, 3, 4 and Comparative Example 1 of this application;
[0031] Figure 4 shows the CV performance of the hard carbon anode materials prepared in Examples 1, 3, 4 and Comparative Example 1 of this application;
[0032] Figure 5 is a rate-of-capacity diagram of the hard carbon anode material prepared in Example 1 of this application;
[0033] Figure 6 shows the hard carbon anode material prepared in Example 1 of this application after 100 cycles at a current of 0.05 CA / g. Detailed Implementation
[0034] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.
[0035] The following examples illustrate the preparation method of bamboo processing residues: 10g of bamboo scraps are crushed in a pulverizer and passed through a 200-mesh sieve. The HCl solution is prepared as follows: Approximately 8.3 ml of concentrated hydrochloric acid is added to a beaker, followed by 500 ml of deionized water. The mixture is stirred until homogeneous and cooled, then diluted to a 1000 ml volumetric flask.
[0036] In the following examples, thiourea was purchased from Aladdin Reagent Network; anhydrous sodium sulfite was purchased from Sinopharm Reagent Network; and sublimed sulfur was purchased from Tuyi Medical Device Specialty Store.
[0037] Example 1
[0038] A method for preparing hard carbon anode materials for ion batteries from sulfur-doped modified bamboo-based biomass includes the following steps:
[0039] (1) Take 10 g of bamboo processing residue, crush it into 200 mesh powder, and dry it in an oven at 80 ℃ until constant weight to obtain the first precursor.
[0040] (2) Add 5 g of thiourea and 100 mL of water to the first precursor obtained in step (1), mix and soak for 24 h, filter, and dry in an oven at 80 ℃ for 12 h to obtain the second precursor.
[0041] (3) The precursor obtained in step (2) is placed in a muffle furnace and heated to 400 ℃ in an air atmosphere at a heating rate of 5 ℃ / min. The temperature is held for 1 h and then naturally cooled to room temperature to obtain the third precursor.
[0042] (4) The third precursor obtained in step (3) is placed in a ball mill at 1200 r / min and ball-milled for 3 min, and then sieved.
[0043] (5) The third precursor powder after sieving in step (4) is subjected to high-temperature carbonization. Under an argon atmosphere, it is heated to 1200 ℃ at a heating rate of 5 ℃ / min and held for 2 h to obtain hard carbon material.
[0044] (6) The hard carbon material obtained in step (5) is stirred, boiled and washed in 0.1 mol / L HCl solution, then washed with deionized water until neutral, and dried in an oven at 80 ℃ for 12 h to obtain the sodium-ion battery hard carbon anode material, denoted as HC-S-0.5.
[0045] Example 2
[0046] The difference from Example 1 is that in step (2), 5 g of thiourea is replaced with 10 g of thiourea to obtain a sodium-ion battery hard carbon anode material, denoted as HC-S-1.
[0047] Example 3
[0048] The difference from Example 1 is that in step (2), 5 g of thiourea is replaced with 8 g of thiourea to obtain a sodium-ion battery hard carbon anode material, denoted as HC-S-0.8.
[0049] Example 4
[0050] The difference from Example 1 is that in step (2), 5 g of thiourea is replaced with 2 g of thiourea to obtain a sodium-ion battery hard carbon anode material, denoted as HC-S-0.2.
[0051] Example 5
[0052] The difference from Example 1 is that in step (2), the first precursor obtained in step (1) is mixed with 2 g of sublimed sulfur in a ball mill at 400 rpm for 1 h to obtain the second precursor. The resulting sodium-ion battery hard carbon anode material is denoted as HC-sublimed sulfur-0.2.
[0053] Example 6
[0054] The difference from Example 1 is that in step (2), 5 g of thiourea is replaced with 2 g of anhydrous sodium sulfite to obtain a hard carbon anode material for sodium-ion batteries, denoted as HC-anhydrous sodium sulfite-0.2.
[0055] Example 7
[0056] The difference from Example 1 is that in step (1), the 200-mesh bamboo processing residue powder is replaced with 50-mesh powder. A hard carbon anode material for sodium-ion batteries is obtained.
[0057] Example 8
[0058] The difference from Example 1 is that in step (1), the 200-mesh bamboo processing residue powder is replaced with 50-100 mesh powder. A hard carbon anode material for sodium-ion batteries is obtained.
[0059] Example 9
[0060] The difference from Example 1 is that in step (1), the 200-mesh bamboo processing residue powder is replaced with 300-mesh powder. A hard carbon anode material for sodium-ion batteries is obtained.
[0061] Example 10
[0062] The difference from Example 1 is that in step (5), the high-temperature carbonization temperature of 1200 ℃ is replaced with 1000 ℃. A hard carbon anode material for sodium-ion batteries is obtained.
[0063] Example 11
[0064] The difference from Example 1 is that in step (5), the high-temperature carbonization temperature of 1200 ℃ is changed to 1400 ℃. A hard carbon anode material for sodium-ion batteries is obtained.
[0065] Example 12
[0066] The difference from Example 1 is that in step (5), the high-temperature carbonization temperature of 1200 ℃ is changed to 1600 ℃. A hard carbon anode material for sodium-ion batteries is obtained.
[0067] Comparative Example 1
[0068] (1) Take 10 g of bamboo processing residue, crush it into 200 mesh powder, and dry it in an oven at 80 ℃ for 12 h to obtain the first precursor.
[0069] (2) The first precursor obtained in step (1) is placed in a muffle furnace and heated to 400 ℃ in an air atmosphere at a heating rate of 5 ℃ / min. The temperature is held for 1 h and then naturally cooled to room temperature to obtain the second precursor.
[0070] (3) The second precursor obtained in step (2) is placed in a ball mill at 1200 r / min and ball-milled for 3 min, and then sieved.
[0071] (4) The second precursor powder after sieving in step (3) is subjected to high-temperature carbonization. Under an argon atmosphere, it is heated to 1200 ℃ at a heating rate of 5 ℃ / min and held for 2 h to obtain hard carbon material.
[0072] (5) The hard carbon material obtained in step (4) is stirred, boiled and washed in 0.1 mol / L HCl solution, then washed with deionized water until neutral, and dried in an oven at 80 ℃ for 12 h to obtain the sodium-ion battery hard carbon anode material, denoted as HC.
[0073] Figure 1 shows TEM images of Comparative Example 1(a) and Example 1(b). Both images exhibit typical structural characteristics of long-range disorder and short-range order. However, their stacking density differs. Comparative Example 1(a) shows more disordered carbon structures and a relatively loose stacking structure; this structural feature is beneficial for charge storage but not for ion diffusion, while the structure of Example 1(b) is relatively dense. Furthermore, Example 1(b) contains more clearly defined closed-pore structures, indicating that it has efficient sodium ion diffusion channels.
[0074] Figure 2 shows the XRD patterns of Comparative Example 1 and Examples 1, 3, and 4. All samples exhibit two broad peaks at 24° and 43°, corresponding to the (002) and (100) crystal planes of the graphite structure. As the doping ratio of S increases, the position of the (002) peak initially shifts to the left, indicating that the interlayer spacing of the material gradually increases. When the doping ratio reaches 0.8, the position of the (002) peak remains almost unchanged, while the interlayer spacing does not change much.
[0075] The sodium-ion battery hard carbon anode materials prepared in Examples 1-13 and Comparative Example 1 were used for sodium-ion battery assembly and electrochemical testing.
[0076] Weigh out hard carbon material, acetylene black, and 5% polyvinylidene fluoride (PVDF) in a mass ratio of 7:2:1. Add an appropriate amount of N-methylpyrrolidone (NMP) and stir until a uniform slurry is formed. Use a 15 μm thick scraper to evenly coat the slurry onto the surface of copper foil. Dry in an 80 ℃ forced-air drying oven for 12 h. Cut the copper foil with active material into 14 mm circular negative electrode sheets, weigh them precisely, and transfer them to a glove box for later use.
[0077] The battery was assembled in an argon glove box with moisture and gas concentrations both less than 0.01 mg / L. A CR2032 battery case was used, with a 1 M / L NaPF6 electrolyte. A sodium metal sheet served as both the counter and reference electrode, and a glass fiber separator was employed. The battery was assembled in the following order from bottom to top: positive electrode case, working electrode, separator, sodium metal sheet, gasket, spring contact, and negative electrode case.
[0078] The electrochemical performance of the prepared sodium-ion half-cell was tested. Specifically, the initial discharge specific capacity (mAh / g) and initial charge specific capacity (mAh / g) were measured within a voltage range of 0.001–2.5 V and a current density of 0.1 C (30 mA / g), and the initial coulombic efficiency was calculated. The results are shown in Table 1 and Figures 3–6.
[0079] Table 1. Charge-discharge performance of the hard carbon materials prepared in Examples 1-13 and Comparative Example 1
[0080]
[0081] As shown in Table 1 and Figures 1-5, Example 1 was the experimental group, and Examples 2, 3, and 4 were the control groups. The effect of the proportion of thiourea added on the electrochemical performance of bamboo-based biomass hard carbon was recorded. Appropriate S doping increases the electrochemical performance of hard carbon materials, while excessive S doping leads to the formation of an unstable solid electrolyte interphase (SEI) film. The hard carbon material provided by Example 1 has the best performance. Based on an initial coulombic efficiency of about 65.9%, its initial discharge specific capacity reached 353.62 mAh / g. At the same time, the capacity remained at about 90% after 100 cycles at a current of 0.05 C. The initial coulombic efficiencies of the hard carbon materials provided by Examples 2, 3, and 4 were 60.8%, 61.4%, and 63.7%, respectively, and the initial charge specific capacities were 291.83 mAh / g, 299.78 mAh / g, and 323 mAh / g.
[0082] Example 1 was the experimental group, and Examples 7, 8, and 9 were the control groups. The effect of the particle size of bamboo processing residues on the electrochemical performance of bamboo-based biomass hard carbon was recorded. As the particle size increased, the performance of the prepared sodium-based hard carbon anode material gradually increased, and the performance change was small after exceeding 200 mesh.
[0083] Example 1 was the experimental group, and Examples 10, 11, and 12 were the control groups. The effect of temperature on the electrochemical performance of bamboo-based biomass hard carbon during high-temperature refining was recorded. The sodium-based hard carbon anode material prepared when the high-temperature refining temperature reached 1200 °C had the best performance.
[0084] Examples 1, 5, and 6 document the effects of different sulfur source treatments. Sublimated sulfur is easily volatilized during high-temperature treatment, leading to uneven distribution of sulfur in the biomass carbon matrix, forming local sulfur-rich areas or undoped areas, affecting the uniformity of the material structure and the stability of sodium storage performance. Anhydrous sodium sulfite, due to its inherent instability, cannot accurately dope sulfur into bamboo-based biomass. The initial coulombic efficiencies of the hard carbon materials provided in Examples 5 and 6 were 61.8% and 55.3%, respectively, and the initial charge specific capacities were 317.8 mAh / g and 273 mAh / g, respectively.
[0085] Example 1 and Comparative Example 1 documented the effects of sulfur doping on bamboo-based biomass hard carbon. S-doped bamboo-based biomass hard carbon significantly increased the interlayer spacing of the hard carbon while reducing the specific surface area, thus decreasing the formation of the SEI film. Simultaneously, the CS bonds provided active sites for sodium ions. The hard carbon material provided in Comparative Example 1 exhibited an initial coulombic efficiency of 62.3% and an initial charge specific capacity of 300.12 mAh / g.
[0086] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing hard carbon anode material for sodium-ion batteries from sulfur-doped modified bamboo-based biomass, characterized in that: Includes the following steps: 1) The bamboo processing residue was crushed into powder and dried to constant weight to obtain the first precursor; 2) The first precursor obtained in step 1) is mixed and impregnated with a sulfur source, filtered and dried to obtain the second precursor; 3) The second precursor obtained in step 2) is placed in a muffle furnace and carbonized at low temperature in an air atmosphere, and cooled to obtain the third precursor; 4) The third precursor obtained in step 3) is ground and then sieved; 5) The third precursor powder after sieving in step 4) is carbonized at high temperature in an inert atmosphere to obtain hard carbon material. 6) The hard carbon material obtained in step 5) is washed with a solution, filtered, and dried to obtain sulfur-doped modified biomass bamboo-based hard carbon material.
2. The method for preparing hard carbon anode material for sodium-ion batteries using sulfur-doped modified bamboo-based biomass according to claim 1, characterized in that: In step 1), the particle size of the pulverized powder is 50~320 mesh.
3. The method for preparing hard carbon anode material for sodium-ion batteries using sulfur-doped modified bamboo-based biomass according to claim 1, characterized in that: In step 2), the sulfur source is selected from one or more of thiourea, sublimed urea, and anhydrous sodium sulfite.
4. The method for preparing hard carbon anode material for sodium-ion batteries using sulfur-doped modified bamboo-based biomass according to claim 1, characterized in that: In step 2), the mass ratio of the first precursor to the sulfur source is 1:0.2~0.
5.
5. The method for preparing hard carbon anode material for sodium-ion batteries using sulfur-doped modified bamboo-based biomass according to claim 1, characterized in that: In step 3), the heating rate for medium-low temperature pre-carbonization is 3~5 ℃ / min, the temperature is 250~400 ℃, and the holding time is 1~2 h.
6. The method for preparing hard carbon anode material for sodium-ion batteries using sulfur-doped modified bamboo-based biomass according to claim 1, characterized in that: In step 4), the ball mill speed is 800~1200 r / min, and the ball milling time is 1~5 min.
7. The method for preparing hard carbon anode material for sodium-ion batteries using sulfur-doped modified bamboo-based biomass according to claim 1, characterized in that: In step 5), the inert gas is nitrogen or argon; the heating rate for high-temperature carbonization is 3~5 ℃ / min, the high-temperature carbonization temperature is 1000~1600 ℃, and the holding time is 2 h.
8. The method for preparing hard carbon anode material for sodium-ion batteries using sulfur-doped modified bamboo-based biomass according to claim 1, characterized in that: In step 6), the washing solution is a 0.1 mol / L HCl aqueous solution. The solution is boiled and washed, then washed with distilled water until neutral, and dried in an oven at 80 °C for 12 h until constant weight.
9. The sodium-ion battery hard carbon anode material prepared by the method for preparing sodium-ion battery hard carbon anode material from sulfur-doped modified bamboo-based biomass according to any one of claims 1 to 8.
10. The application of the sodium-ion battery hard carbon anode material according to claim 9 in the anode of a sodium-ion battery.