Radial wedge-shaped mesoporous carbon sphere negative electrode material and preparation method and application thereof

Abstract

The invention provides a radial wedge-shaped mesoporous carbon sphere negative electrode material as well as a preparation method and application thereof, and belongs to the technical field of energy storage materials. The preparation method of the radial wedge-shaped mesoporous carbon sphere negative electrode material comprises the following steps: mixing and stirring phloroglucinol, a nonionic surfactant, mesitylene, ethidene diamine and a solvent, and sequentially centrifuging, drying and carbonizing to obtain the radial wedge-shaped mesoporous carbon sphere negative electrode material. The radial wedge-shaped mesoporous carbon sphere negative electrode material prepared by the invention has a radial mesoporous morphology, and is beneficial to improving the diffusion rate of ions and electrons and buffering volume expansion caused by Na < + > storage.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage materials, and in particular to a radial wedge-shaped mesoporous carbon sphere negative electrode material and a preparation method and application thereof. Background Art

[0002] Secondary batteries that can store green renewable energy (such as solar energy, wind energy and hydropower) have become an effective strategy. As the most widely used type of secondary battery, lithium-ion batteries (LIBs) are limited by the limited reserves, uneven distribution and high cost of lithium resources, making it difficult to fully meet the needs of the energy storage market and large-scale power grids. In view of the similarity between sodium and lithium in chemical properties, coupled with the advantages of abundant sodium resources, easy extraction and processing, and low cost, sodium-ion batteries (SIBs) are increasingly regarded as an ideal alternative technology for LIBs. To date, a variety of compounds, including layered transition metal oxides, polyanionic compounds, Prussian blue analogs and organic compounds, have been verified to have the potential to be used as SIB positive electrode materials. However, in the existing technology, there is still a lack of suitable negative electrode materials that can match these positive electrode materials. In addition, due to the sodium ion (Na + ) has a radius (0.102nm) smaller than that of lithium ions (Li + ) has a larger radius (0.076nm), which leads to the challenges of slow Na+ diffusion kinetics and large volume change in the negative electrode material during sodium storage, making the commercial negative electrode materials (such as graphite and silicon) widely used in lithium-ion batteries unsuitable for SIB. Therefore, it is urgent to develop a high-performance SIB negative electrode material.

[0003] Carbon materials, with their low cost, good conductivity and high stability, are widely considered to be one of the most promising negative electrode material options in sodium-ion batteries (SIBs). Among the many carbon materials, mesoporous carbon shows significant development potential due to its high rate performance and long cycle life in SIB negative electrode applications. Existing studies have pointed out that the sodium storage capacity can be effectively improved by adjusting the morphology, structure and chemical composition of mesoporous carbon. This strategy not only optimizes the structural properties of the material, but also enhances its performance in electrochemical energy storage systems, providing an important material basis for the advancement of SIB technology.

[0004] In the prior art, the common methods for adjusting the morphology of mesoporous carbon include hard template method (such as SiO 2 , MgO), physical activation (such as CO 2 , CO) and chemical activation methods (such as KOH, H 3 PO 4). The hard template method can accurately control the structure and morphology of mesoporous carbon, but its high cost, complex process and the uniformity of product shape and size limit its wide application. Although the physical activation method is less corrosive to the equipment, the resulting carbon structure is mainly microporous. In contrast, although the traditional chemical activation method can effectively generate mesoporous carbon with a hierarchical mesoporous structure, this method may corrode production equipment and pollute the environment. In view of this, the development of a simple and effective new method to adjust the morphological structure of mesoporous carbon has become an important direction of current research. The solvent-induced self-assembly method is based on the self-assembly process between the precursor material and the triblock copolymer, in which the template can be easily removed during the carbonization process. This method simplifies the synthesis steps and effectively avoids the complexity of template removal in the hard template method. This technology not only improves the convenience of operation, but also reduces the technical difficulty of production, providing a more efficient and lower-cost solution for the preparation of mesoporous carbon materials. However, there are few literatures on the preparation of SIB mesoporous carbon anodes by solvent-induced self-assembly.

[0005] Therefore, it is of great significance to study a low-cost and simple process-based solvent-induced self-assembly method and radial wedge-shaped mesoporous carbon sphere negative electrode material with complex shapes and sizes, and its application in sodium batteries. Summary of the invention

[0006] The purpose of the present invention is to provide a radial wedge-shaped mesoporous carbon sphere negative electrode material and a preparation method and application thereof, so as to solve the above-mentioned technical problems.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a radial wedge-shaped mesoporous carbon sphere negative electrode material, comprising the following steps:

[0009] Phloroglucinol, a nonionic surfactant, mesitylene, ethylenediamine and a solvent are mixed, and then the mixture is centrifuged, dried, preheated and carbonized in sequence to obtain a radial wedge-shaped mesoporous carbon sphere negative electrode material;

[0010] The nonionic surfactant is a polyoxyethylene-polyoxypropylene copolymer.

[0011] Furthermore, the usage ratio of phloroglucinol, nonionic surfactant, mesitylene, ethylenediamine and solvent is 0.4-0.6 g: 0.5-1.5 g: 1.5-2.5 mL: 200-300 μL: 100-300 mL.

[0012] Furthermore, the polyoxyethylene-polyoxypropylene copolymer comprises bleoxamer F127 and / or bleoxamer P123, and the mass ratio of bleoxamer F127 to bleoxamer P123 is 1-3:1-3.

[0013] Furthermore, the mixing is carried out under stirring, the stirring speed is 500 to 800 rpm, and the stirring time is 18 to 24 hours;

[0014] The drying is freeze drying, the freeze drying temperature is -65 to -48°C, and the freeze drying time is 18 to 24 hours.

[0015] Furthermore, the solvent comprises ethanol and / or water, and the volume ratio of the ethanol to water is 1-2:1-2.

[0016] Furthermore, the preheating temperature is 180-350° C., the heating rate to the preheating temperature after drying is 1-3° C. / min, and the preheating time is 90-120 min.

[0017] Furthermore, the carbonization temperature is 600-800° C., the heating rate to the carbonization temperature is 1-2° C. / min, and the carbonization time is 1-2 h.

[0018] Furthermore, the preheating and carbonization are independently performed under a protective atmosphere, the protective atmosphere independently contains nitrogen, argon or helium, and the flow rate of the protective atmosphere is independently 50 to 120 mL / min.

[0019] The invention also provides a radial wedge-shaped mesoporous carbon sphere negative electrode material.

[0020] The present invention also provides an application of a radial wedge-shaped mesoporous carbon sphere negative electrode material in a sodium ion battery.

[0021] Beneficial effects of the present invention:

[0022] (1) The present invention adopts a liquid-liquid synthesis strategy of solvent-induced self-assembly to successfully prepare a carbon sphere negative electrode material with a unique radial wedge-shaped mesoporous structure. This preparation process is simple and effectively overcomes many inherent defects of the traditional hard template method and physical and chemical activation methods. In addition, the present invention uses phloroglucinol, F127, P123, mesitylene and ethylenediamine as raw materials, and selects water and ethanol as solvents. These raw materials are low-cost, easy to obtain and non-toxic, thereby ensuring the economy and environmental friendliness of the synthesis process;

[0023] (2) The radial wedge-shaped mesoporous carbon sphere negative electrode material prepared by the present invention has a radial mesoporous morphology. This structure significantly improves the diffusion rate of ions and electrons and effectively buffers the sodium ion (Na +) volume expansion caused during storage. In addition, the micropores on the mesoporous pore walls can significantly increase the specific surface area and defect number of carbon materials and widen the carbon layer spacing, thereby promoting the transport kinetics and diffusion rate of sodium ions. The presence of high mesoporous content is not only conducive to the transport of sodium ions, but also increases the contact area between the electrode and the electrolyte, thereby improving the electrochemical performance.

[0024] (3) The radial wedge-shaped mesoporous carbon sphere negative electrode material synthesized in the present invention proves that the solvent-induced self-assembly strategy can not only design and construct advanced electrode materials in SIB systems, but also has helpful and guiding significance for other energy storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a SEM image of the through-type mesoporous carbon active negative electrode material obtained in Example 1;

[0026] Figure 2 This is the SEM image of the negative electrode material obtained in Comparative Example 2;

[0027] Figure 3 This is the SEM image of the negative electrode material obtained in Comparative Example 3;

[0028] Figure 4 This is the SEM image of the negative electrode material obtained in Comparative Example 4;

[0029] Figure 5 TEM image of the negative electrode material obtained in Comparative Example 5;

[0030] Figure 6 is the X-ray diffraction pattern of the negative electrode material obtained in Example 1;

[0031] Figure 7 This is the BET diagram of the negative electrode material obtained in Example 1;

[0032] Figure 8 The charge and discharge curve of the negative electrode material obtained in Example 1 applied to a sodium ion battery;

[0033] Fig. 9 The charge and discharge working spectrum of the negative electrode material obtained in Example 1 applied to a sodium ion battery;

[0034] Fig.10 The charge and discharge working spectrum of the negative electrode material obtained in Example 1 applied to a sodium ion battery;

[0035] Fig.11 The charge and discharge working spectrum of the negative electrode materials obtained in Comparative Examples 1 to 3 applied to sodium ion batteries;

[0036] Fig.12 The charge and discharge working spectrum of the negative electrode materials obtained in Comparative Examples 1 to 3 applied to sodium ion batteries;

[0037] Fig.13 This is a cyclic voltammetry curve of the negative electrode material obtained in Example 1 applied to a sodium ion battery at 0.2 mV / s. DETAILED DESCRIPTION

[0038] The present invention provides a method for preparing a radial wedge-shaped mesoporous carbon sphere negative electrode material, comprising the following steps:

[0039] Phloroglucinol, a nonionic surfactant, mesitylene, ethylenediamine and a solvent are mixed, and then the mixture is centrifuged, dried, preheated and carbonized in sequence to obtain a radial wedge-shaped mesoporous carbon sphere negative electrode material;

[0040] The nonionic surfactant is a polyoxyethylene-polyoxypropylene copolymer.

[0041] In the present invention, the dosage ratio of the phloroglucinol, nonionic surfactant, mesitylene, ethylenediamine and solvent is 0.4-0.6g: 0.5-1.5g: 1.5-2.5mL: 200-300μL: 100-300mL, preferably 0.4-0.6g: 0.8-1.2g: 1.7-2.4mL: 200-250μL: 100-300mL, and further preferably 0.5g: 0.8-1.0g: 2.0-2.2mL: 275-285μL: 200-240mL.

[0042] In the present invention, the phloroglucinol provides a carbon source for the preparation of radial wedge-shaped mesoporous negative electrode materials;

[0043] The nonionic surfactant and mesitylene provide templates for the preparation of radial wedge-shaped mesoporous negative electrode materials;

[0044] The ethylenediamine is a polymerization initiator of the radial wedge-shaped mesoporous negative electrode material.

[0045] In the present invention, the polyoxyethylene-polyoxypropylene copolymer comprises bleoxamer F127 and / or bleoxamer P123, and the mass ratio of bleoxamer F127 to bleoxamer P123 is 1-3:1-3, preferably 1:3 or 3:1 or 1:1.

[0046] In the present invention, the bleoxamer F127 and bleoxamer P123 are both from Aladdin Biochemical Technology Co., Ltd.

[0047] In the present invention, F127 and P123 are dissolved in a solvent (ethanol and water) to form a spherical micelle template, mesitylene interacts with the hydrophobic segment of the micelle, and phloroglucinol interacts with the hydrophilic segment to form a preliminary self-assembled network structure. Then, under the initiation of ethylenediamine, phloroglucinol undergoes condensation polymerization to form a spherical precursor. Under the action of solvent extraction, mesitylene is removed. During the preheating process, F127 and P123 decompose to form CO and CO 2 When the temperature gradually rises to the carbonization temperature, the phloroglucinol polymer decomposes and carbonizes to form CO 2 , CO, H 2 O and carbon materials. The generated gases can etch the carbon materials together, that is, the secondary activation and pore-forming process. After removing impurities from the pyrolysis products, radial wedge-shaped mesoporous carbon spheres were obtained.

[0048] In the present invention, the mixing is performed under stirring, the stirring speed is 500-800 rpm, preferably 600-700 rpm, more preferably 650 rpm; the stirring time is 18-24 h, preferably 20-22 h, more preferably 21 h.

[0049] In the present invention, the drying is freeze drying, the freeze drying temperature is -65 to -48°C, preferably -60 to -50°C, and more preferably -55°C; the freeze drying time is 18 to 24h, preferably 20 to 22h, and more preferably 21h.

[0050] In the present invention, the solvent comprises ethanol and / or water, preferably ethanol and water, and the volume ratio of ethanol to water is 1-2:1-2, preferably 1:1.

[0051] In the present invention, the preheating temperature is 180-350°C, preferably 200-320°C, and more preferably 250-300°C; the heating rate to the preheating temperature after drying is 1-3°C / min, preferably 2°C / min; the preheating time is 90-120min, preferably 100-110min.

[0052] In the present invention, the carbonization temperature is 600-800°C, preferably 650-750°C, and more preferably 700°C; the heating rate to the carbonization temperature is 1-2°C / min, preferably 2°C / min; the carbonization time is 1-2h, preferably 2h.

[0053] The preheating and carbonization are independently carried out under a protective atmosphere, and the protective atmosphere independently contains nitrogen, argon or helium, preferably nitrogen; the flow rate of the protective atmosphere is independently 50-120 mL / min, preferably 60-110 mL / min, and more preferably 80-100 mL / min.

[0054] In the present invention, after the carbonization is completed, the carbonization product is further subjected to post-treatment; the post-treatment comprises the following steps: removing impurities, separating, washing and drying the carbonization product in sequence;

[0055] The separation is preferably centrifugal separation;

[0056] The washing is preferably carried out by washing with anhydrous ethanol and deionized water in sequence, and the number of washings is preferably 2 to 3 times;

[0057] The drying temperature is preferably 70-120° C., more preferably 80-110° C., and more preferably 90-100° C.; the drying time is preferably 15-27 h, more preferably 18-25 h, and more preferably 20-22 h.

[0058] The invention also provides a radial wedge-shaped mesoporous carbon sphere negative electrode material.

[0059] The present invention also provides an application of a radial wedge-shaped mesoporous carbon sphere negative electrode material in a sodium ion battery.

[0060] In the present invention, the preparation of the sodium ion battery comprises the following steps:

[0061] The radial wedge-shaped mesoporous carbon sphere negative electrode material, the conductive agent, the binder and N-methylpyrrolidone are mixed to obtain a mixture, and the obtained mixture is evenly dropped onto a copper foil and dried to form a negative electrode sheet; in a glove box filled with argon, the negative electrode sheet, the glass fiber separator and the sodium metal disc are assembled into a sodium ion battery.

[0062] In the present invention, the conductive agent is preferably a conductive agent Super-P, and the binder is preferably polyvinylidene fluoride;

[0063] The mass ratio of the radial wedge-shaped mesoporous carbon sphere negative electrode material, the conductive agent and the binder is preferably 7-8.5:0.5-2:1, and more preferably 7.5-8.0:1.5:1; the volume ratio of the N-methylpyrrolidone and the binder is preferably 1:1.3-2, and more preferably 1:1.5-1.7, and more preferably 1:1.6; the drying temperature is preferably 60-110°C, and more preferably 85-95°C, and more preferably 88-90°C.

[0064] In the present invention, in the sodium ion battery, the solute of the electrolyte is preferably sodium hexafluorophosphate, the solvent of the electrolyte is preferably ethylene carbonate and diethyl carbonate, and the concentration of the electrolyte is preferably 1 to 1.3M, and more preferably 1.1 to 1.2M.

[0065] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0066] Example 1

[0067] 0.5g of phloroglucinol, 0.5g of F127, 0.5g of P123, 2.1mL of mesitylene and 200μL of ethylenediamine were mixed with a solvent (100mL of water and 100mL of ethanol) at 600rpm for 24h, and the mixed product was separated into solid and liquid by centrifugation, and washed with ethanol and water for 3 times. Freeze-dried at -50℃ for 24h, and after freeze-drying, heated to 200℃ at a heating rate of 2℃ / min and kept warm for 2h in a nitrogen atmosphere with a flow rate of 80mL / min to complete preheating, and then the preheated product was heated to 800℃ at a heating rate of 2℃ / min and kept warm for 2h to obtain the carbonized product. Recorded as "PCS"

[0068] Example 2

[0069] 0.5g of phloroglucinol, 0.25g of F127, 0.75g of P123, 2.1mL of mesitylene and 200μL of ethylenediamine were mixed with a solvent (100mL of water and 100mL of ethanol) at 600rpm for 24h, and the mixed product was separated into solid and liquid by centrifugation, and washed with ethanol and water 3 times. Freeze-dried at -50℃ for 24h, and after freeze-drying, heated to 200℃ at a heating rate of 2℃ / min and kept warm for 2h in a nitrogen atmosphere with a flow rate of 80mL / min to complete preheating, and then the preheated product was heated to 800℃ at a heating rate of 2℃ / min and kept warm for 2h to obtain the carbonized product. Recorded as "PCS-2"

[0070] Example 3

[0071] 0.5g of phloroglucinol, 0.75g of F127, 0.25g of P123, 2.1mL of mesitylene and 200μL of ethylenediamine were mixed with a solvent (100mL of water and 100mL of ethanol) at 600rpm for 24h, and the mixed product was separated into solid and liquid by centrifugation, and washed with ethanol and water 3 times. Freeze-dried at -50℃ for 24h, and after freeze-drying, heated to 200℃ at a heating rate of 2℃ / min and kept warm for 2h in a nitrogen atmosphere with a flow rate of 80mL / min to complete preheating, and then the preheated product was heated to 800℃ at a heating rate of 2℃ / min and kept warm for 2h to obtain the carbonized product. Recorded as "PCS-3"

[0072] Comparative Example 1

[0073] The difference from Example 1 is that the addition of mesitylene, F127 and P123 in Example 1 is omitted, and the other steps are the same as Example 1 to obtain a negative electrode material, which is recorded as "C".

[0074] Comparative Example 2

[0075] The difference from Example 1 is that the addition of F127 and P123 in Example 1 is omitted, and the other steps are the same as Example 1 to obtain a negative electrode material, which is recorded as "CS".

[0076] Comparative Example 3

[0077] The difference from Example 1 is that the addition of mesitylene in Example 1 is omitted, and the other steps are the same as Example 1 to obtain a negative electrode material, which is recorded as "CS-2".

[0078] Characterization and performance testing:

[0079] 1. Morphology and structure: The morphology and structure of the negative electrode materials obtained in Example 1 and Comparative Examples 1 to 3 were observed by scanning electron microscopy (SEM).

[0080] 2. Morphology and structure: The morphology and structure of the negative electrode material obtained in Example 1 were observed by transmission electron microscopy (TEM).

[0081] 3. Phase composition: The phase composition of the negative electrode material obtained in Example 1 was determined by X-ray diffraction.

[0082] 4. Specific surface area and pore structure: The negative electrode material obtained in Example 1 was subjected to nitrogen adsorption and desorption at 77K to test the specific surface area and pore volume of the negative electrode material.

[0083] The SEM image of the radial wedge-shaped mesoporous carbon sphere negative electrode material obtained in Example 1 is as follows Figure 1 As shown. Figure 1 It can be seen that the negative electrode material PCS obtained in Example 1 is an ordered mesoporous structure.

[0084] The SEM image of the negative electrode material obtained in Comparative Example 1 is as follows Figure 2 As shown. Figure 2 It can be seen that the negative electrode material CS obtained in Comparative Example 1 has a non-mesoporous morphology.

[0085] The SEM image of the negative electrode material obtained in Comparative Example 2 is as follows Figure 3 As shown. Figure 3 It can be seen that the negative electrode material CS-2 obtained in Comparative Example 2 has a non-mesoporous morphology.

[0086] The SEM image of the negative electrode material obtained in Comparative Example 3 is as follows Figure 4 As shown. Figure 4 It can be seen that the negative electrode material C obtained in Comparative Example 3 has a non-mesoporous morphology.

[0087] The TEM image of the radial wedge-shaped mesoporous carbon sphere negative electrode material obtained in Example 1 is as follows Figure 1 As shown. Figure 5 It can be seen that the negative electrode material PCS obtained in Example 1 is a through-type ordered mesoporous structure.

[0088] The X-ray diffraction pattern of the negative electrode material obtained in Example 1 is as follows: Figure 6 As shown. Combined Figures 6-7 It can be seen that the negative electrode material PCS obtained in Example 1 has a through-type ordered mesoporous structure, a large interlayer spacing and a specific surface area; it can be seen that the negative electrode material obtained in Example 1 is conducive to enhancing the wettability of the electrolyte, and has the advantages of high conductivity, large carbon interlayer spacing, many active sites and good structural stability, which is conducive to the electron and Na + transmission.

[0089] Application Examples

[0090] The negative electrode material, conductive agent Super-P and polyvinylidene fluoride are mixed in a mass ratio of 7.5:1.5:1, and then added into N-methylpyrrolidone (the volume ratio of N-methylpyrrolidone to polyvinylidene fluoride is 1:1.5) and mixed. The obtained mixture is evenly dropped onto a copper foil so that the thickness of the mixture dropped on the copper foil is 200 μm. The mixture is placed in an oven and dried at 75°C to obtain a negative electrode sheet. The negative electrode sheet, glass fiber separator and sodium metal disc are assembled into a sodium ion battery in a glove box filled with argon.

[0091] The negative electrode materials obtained in Comparative Examples 1 to 3 were assembled into a sodium ion battery according to the above steps; the negative electrode materials obtained in Example 1 were assembled into a sodium ion battery according to the above steps, and recorded as "PCS-Na".

[0092] The sodium ion battery obtained above was subjected to the following performance tests.

[0093] Test method: The assembled sodium-ion battery was tested for cyclic voltammetry curve, constant current charge-discharge curve, rate performance and electrochemical impedance at room temperature using Chenhua CHI660E electrochemical workstation and Xinwei CT-4008T.

[0094] like Fig.13 As shown in the cyclic voltammetry (CV) curve of PCS negative electrode material at 0.2mV / s, the cathode peaks are located at 1.0V, 0.56V and 0.01V. In the first cycle CV curve of PCS negative electrode, the cathode peak close to 0.01V represents the underpotential deposition of Na atoms or Na+ insertion, and the remaining cathode peaks reflect the electrolyte decomposition, the formation of solid electrolyte interface (SEI) layer, and Na + At the same time, the CV curves of the PCS negative electrode in the second and third cycles almost overlap, indicating that it has a high degree of stability. In addition, the CV curve of the PCS negative electrode above 1.5V shows a rectangular feature, revealing its capacitive sodium storage behavior, including the double layer to Na + Physical adsorption of Na + reversible chemical adsorption.

[0095] like Fig. 9 As shown in the first cycle of constant current charge and discharge (GCD) curve of PCS negative electrode at a current density of 0.1A / g, its reversible capacity in ester-based electrolyte is 658.5mAh / g, and the corresponding first coulombic efficiency (ICE) is 59.2%. In addition, Fig.10 It can be seen that the specific capacity of the PCS negative electrode after 10,000 cycles at a current density of 20 A / g is 255.6 mAh / g. This excellent reversible capacity and high ICE are mainly attributed to the perforated mesoporous morphology / microstructure of the PCS negative electrode, which significantly improves the conductivity and electrolyte contact area and accelerates the Na + The transmission rate.

[0096] In summary, PCS anode exhibits excellent Na + The storage performance is mainly attributed to its through-mesoporous morphology / microstructure, which effectively promotes the + / Electron transport and Na + The mesoporous structure also provides a good storage environment for Na + In contrast, the negative electrode materials CS, CS-2 and C prepared in Comparative Examples 1 to 3 have a spherical morphology without mesopores, which limits the Na + The rapid migration of Na + The migration energy barrier reduces the diffusion capacity and electrode wettability ( Figures 11-12 ). Therefore, the electrochemical performances of the negative electrode materials prepared in Comparative Examples 1 to 3 are inferior to that of the PCS negative electrode material prepared in Example 1.

[0097] It can be seen from the above embodiments that the present invention provides a radial wedge-shaped mesoporous carbon sphere negative electrode material and its preparation method and application. The radial wedge-shaped mesoporous carbon sphere negative electrode material prepared by the present invention has a radial mesoporous morphology. This structure significantly improves the diffusion rate of ions and electrons and effectively buffers sodium ions (Na + ) volume expansion caused during storage. In addition, the micropores on the mesoporous pore walls can significantly increase the specific surface area and defect number of carbon materials and widen the carbon layer spacing, thereby promoting the transport kinetics and diffusion rate of sodium ions. The presence of high mesoporous content is not only conducive to the transport of sodium ions, but also increases the contact area between the electrode and the electrolyte, thereby improving the electrochemical performance.

[0098] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a radial wedge-shaped mesoporous carbon sphere negative electrode material, characterized in that: The following steps are involved: The phloroglucinol, nonionic surfactant, mesitylene, ethylenediamine and solvent are mixed, and then the mixture is centrifuged, dried, preheated and carbonized in sequence to obtain a radial wedge-shaped mesoporous carbon sphere negative electrode material; The nonionic surfactant is a polyoxyethylene-polyoxypropylene copolymer.

2. The method for preparing the radial wedge-shaped mesoporous carbon sphere negative electrode material according to claim 1, characterized in that: The dosage ratio of the phloroglucinol, the nonionic surfactant, mesitylene, ethylenediamine and the solvent is 0.4-0.6 g: 0.5-1.5 g: 1.5-2.5 mL: 200-300 μL: 100-300 mL.

3. The method for preparing the radial wedge-shaped mesoporous carbon sphere negative electrode material according to claim 1, characterized in that: The polyoxyethylene-polyoxypropylene copolymer comprises bleoxamer F127 and / or bleoxamer P123, and the mass ratio of bleoxamer F127 to bleoxamer P123 is 1-3:1-3.

4. The method for preparing the radial wedge-shaped mesoporous carbon sphere negative electrode material according to any one of claims 1 to 3, characterized in that: The mixing is carried out under stirring, the stirring speed is 500-800 rpm, and the stirring time is 18-24 hours; The drying is freeze drying, the freeze drying temperature is -65 to -48°C, and the freeze drying time is 18 to 24 hours.

5. The method for preparing the radial wedge-shaped mesoporous carbon sphere negative electrode material according to claim 1 or 3, characterized in that: The solvent comprises ethanol and / or water, and the volume ratio of the ethanol to water is 1-2:1-2.

6. The method for preparing the radial wedge-shaped mesoporous carbon sphere negative electrode material according to claim 5, characterized in that: The preheating temperature is 180-350° C., the heating rate to the preheating temperature after drying is 1-3° C. / min, and the preheating time is 90-120 min.

7. The method for preparing the radial wedge-shaped mesoporous carbon sphere negative electrode material according to claim 6, characterized in that: The carbonization temperature is 600-800° C., the heating rate to the carbonization temperature is 1-2° C. / min, and the carbonization time is 1-2 hours.

8. The method for preparing the radial wedge-shaped mesoporous carbon sphere negative electrode material according to claim 6 or 7, characterized in that: The preheating and carbonization are independently performed under a protective atmosphere, the protective atmosphere independently comprises nitrogen, argon or helium, and the flow rate of the protective atmosphere independently ranges from 50 to 120 mL / min.

9. The radial wedge-shaped mesoporous carbon sphere negative electrode material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the radial wedge-shaped mesoporous carbon sphere negative electrode material according to claim 9 in sodium ion batteries.

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