Lithium-carbon composite material as well as preparation method and application thereof

Abstract

The invention discloses a lithium-carbon composite material as well as a preparation method and application thereof, and relates to the technical field of lithium batteries. According to the preparation method, an inert material is taken as an anode, a porous carbon material is taken as a cathode, composite chlorine salt is taken as an electrolyte, high-temperature molten salt electrolysis is carried out under the conditions that the temperature is 380-450 DEG C and the current density is 1.0-1.5 A / cm < 2 >, and the lithium-carbon composite material is prepared above the cathode. Preparation equipment is simple to build, the production process is short, one-step synthesis is achieved through a fused salt electrolysis method, and the good industrial popularization potential is achieved; in the preparation process, when lithium is generated in pores of the carbon material, tiny carbon particles generated by erosion and metal lithium are combined and wrapped in situ and float on the surface of the electrolyte to generate the lithium-carbon material, the atomic-level mixing ensures the uniformity of carbon in lithium, agglomeration is avoided, and the electrochemical performance of the material is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and more specifically, to a lithium-carbon composite material, its preparation method, and its application. Background Technology

[0002] Lithium metal, as a promising next-generation anode material, has long been a research focus in the field of lithium batteries. However, in practical applications, its development is constrained by multiple factors: uncontrollable lithium dendrite growth, the formation and accumulation of inactive lithium, significant volume expansion effects, and unstable solid electrolyte interphase (SEI) films, which seriously hinder the commercialization of lithium metal.

[0003] To address the inherent defects of pure lithium metal, researchers have focused on composite strategies, combining lithium metal with other functional materials to obtain composite anode materials that possess both high energy density and excellent cycle stability. Among these, carbon materials have attracted significant attention due to their wide availability, low cost, and tunable structure, making their composite study with lithium metal particularly noteworthy. Lithium-carbon composite materials can effectively mitigate electrode volume changes during cycling and significantly suppress lithium dendrite growth, exhibiting superior overall performance.

[0004] Currently, there are various methods for preparing lithium-carbon composite materials, mainly including: melt impregnation method—heating metallic lithium to 200-300℃ under an inert atmosphere to form a lithium liquid, which is then composited with a porous carbon matrix. This method is simple but requires strict environmental control; vapor deposition method—heating lithium to a high temperature in a vacuum reaction chamber to generate lithium vapor, which is then condensed on the surface of a preheated carbon matrix to form a core-shell structure. This method requires sophisticated equipment and is expensive; chemical lithiation method—directly synthesizing lithium through the redox reaction of lithium reagents with carbon materials. It has the advantages of simple operation and mild reaction conditions, but the purity of the product is difficult to control; in addition, there is mechanical ball milling method—using high-energy mechanical force to drive the interfacial composite of lithium powder and carbon materials. Although it has the potential for industrial production, it may damage the original structure of the material.

[0005] Therefore, it is particularly important to find a lithium-carbon composite material with simple equipment and process, and good product uniformity and consistency.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a lithium-carbon composite material, its preparation method, and its application, in order to solve the above-mentioned technical problems.

[0008] This invention is implemented as follows: In a first aspect, embodiments of the present invention provide a method for preparing a lithium-carbon composite material, comprising the following steps: Using an inert material as the anode, porous carbon material as the cathode, and a composite chloride salt as the electrolyte, the experiment was conducted at a temperature of 380℃-450℃ and a current density of 1.0 A / cm². 2 -1.5A / cm 2 Under certain conditions, an electrolytic process was carried out to obtain a lithium-carbon composite material; The porous carbon material has a carbon particle size of 0.5 μm-10 μm and a bulk density of 0.8 g / cm³. 3 -1.7g / cm 3 ; Complex chloride salts include lithium chloride and potassium chloride, wherein the mass percentage of lithium chloride is 45%-55%.

[0009] Secondly, embodiments of the present invention provide a lithium-carbon composite material, prepared by the aforementioned preparation method, wherein the carbon content is 5 wt.%-35 wt.%.

[0010] Thirdly, embodiments of the present invention provide a lithium battery, including a lithium-carbon composite material prepared by the aforementioned preparation method or a lithium-carbon composite material prepared by the aforementioned method.

[0011] The present invention has the following beneficial effects: The method for preparing lithium-carbon composite materials provided in this invention features simple equipment setup, a short production process, and one-step synthesis via molten salt electrolysis, making it easy for large-scale industrial application. Lithium is generated at the cathode of the carbon material, rather than through simple mixing. During the preparation process, while lithium is generated in the pores of the carbon material, tiny carbon particles produced by erosion combine and encapsulate with metallic lithium in situ, floating on the electrolyte surface to form lithium-carbon material. This "atomic-level" mixing ensures that lithium is highly uniformly dispersed in the carbon-based material, avoiding agglomeration and greatly improving the electrochemical performance of the material. By precisely controlling parameters such as current density, volume density, temperature, and porous carbon material, the kinetics of the metallic lithium crystallization process can be regulated, thereby controlling the microstructure of the product. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 The lithium-carbon composite material prepared in Example 1; Figure 2 The image shows the SEM morphology of the lithium-carbon composite material prepared in Example 1. Figure 3Impedance spectrum of a symmetrical battery before cycling; Figure 4 The impedance spectrum of a symmetrical battery after 100 cycles. Figure 5 This is a symmetrical battery cycle curve. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0015] This invention employs a high-temperature molten salt electrolysis method to prepare lithium-carbon composite materials. The equipment and process used are simple, and the resulting lithium-carbon composite materials exhibit good uniformity and consistency. The specific implementation process is as follows: In a first aspect, embodiments of the present invention provide a method for preparing a lithium-carbon composite material, comprising the following steps: Using an inert material as the anode, porous carbon material as the cathode, and a composite chloride salt as the electrolyte, the experiment was conducted at a temperature of 380℃-450℃ and a current density of 1.0 A / cm². 2 -1.5A / cm 2 Under certain conditions, an electrolytic process was carried out to obtain a lithium-carbon composite material; The porous carbon material has a carbon particle size of 0.5 μm-10 μm and a bulk density of 0.8 g / cm³. 3 -1.7g / cm 3 ; Complex chloride salts include lithium chloride and potassium chloride, wherein the mass percentage of lithium chloride is 45%-55%.

[0016] It should be noted that the electrolytic treatment of this invention is essentially a high-temperature molten salt electrolysis method. The principle of preparing lithium-carbon composite materials is as follows: molten chloride salt is used as the electrolyte, and it is brought to a molten state at high temperature to form an ionic conductor. Under the action of an electric field, lithium ions in the molten salt rapidly migrate to the cathode and undergo a reduction reaction: Li + + e - →Li. The nascent lithium atoms are extremely active and will immediately intercalate, alloy, or chemically react with carbon cathode materials, forming in-situ compact lithium-carbon complexes (such as LiC6) that aggregate on the surface.

[0017] Generally, the higher the electrolysis temperature, the longer the electrolysis time, the higher the voltage, and the lower the cathode resistivity during electrolysis, the greater the lithium metal production and the higher the lithium content in the lithium-carbon material. However, excessively high temperatures can lead to the volatilization and melting of lithium metal, resulting in greater burn-off and a decrease in the amount of lithium metal. Excessive voltage and current density can cause more impurities to precipitate and enter the lithium-carbon material.

[0018] For example, the temperature can be selected from any one of 380°C, 390°C, 400°C, 420°C, 430°C, and 450°C, or other values ​​within the range of 380°C to 450°C; the current density can be selected from 1.0 A / cm². 2 1.1A / cm 2 1.2A / cm 2 1.3A / cm 2 1.4A / cm 2 and 1.5A / cm 2 Any one of them, or 1.0 A / cm 2 -1.5A / cm 2 Other values ​​within the range.

[0019] The equipment for preparing lithium-carbon composite materials according to this invention is simple to set up, the production process is short, and it is synthesized in one step by molten salt electrolysis, which is easy to promote on a large scale in industrial applications.

[0020] Furthermore, in the compound chloride salt lithium chloride and potassium chloride, the mass ratio of lithium chloride to potassium chloride is 1:1.

[0021] In an optional embodiment, the porous carbon material is selected from at least one of carbon nanotubes, graphene, biochar, and anthracite.

[0022] It should be noted that the interconnected hierarchical channels of porous carbon materials provide a rapid diffusion path for electrolyte ions, ensuring efficient electron transport inside the electrode, reducing ohmic polarization, and thus improving power density and energy efficiency.

[0023] In this invention, porous carbon material is used as the cathode. After lithium is generated at the cathode, it immediately intercalates, alloys, or chemically reacts with the porous carbon material of the cathode, forming a tightly aggregated lithium-carbon composite (such as LiC6) on the surface in situ. In addition, some tiny carbon particles generated by erosion at the cathode combine and encapsulate metallic lithium in situ, and float on the electrolyte surface to form lithium-carbon material. This is not a simple mixing. This "atomic-level" mixing ensures that lithium can be highly uniformly dispersed in the carbon-based material, avoiding agglomeration and greatly improving the electrochemical performance of the material.

[0024] In an optional embodiment, the carbon particle size of the porous carbon material is 1μm-5μm.

[0025] It should be noted that large-particle-size porous carbon materials serve as the main framework to ensure overall density and conductivity, while small-particle-size porous carbon materials fill the gaps between the large-particle-size materials, providing more nucleation sites and improving interfacial contact. The large specific surface area of ​​the small-particle-size materials also means a larger contact area with the electrolyte, which is beneficial for in-situ bonding and encapsulation with lithium generated at the cathode.

[0026] In an optional embodiment, the bulk density of the porous carbon material is 1.0 g / cm³. 3 -1.5 g / cm 3 .

[0027] It should be noted that bulk density and porosity are usually inversely related. Low bulk density generally means high porosity.

[0028] If the bulk density is too high, the electrode is robust and durable, but the electrolyte is difficult to wet, limiting the effective electrochemical reaction area. The reaction mainly concentrates on the electrode surface, resulting in low internal utilization and a limited overall reaction rate (current), thus reducing the yield.

[0029] If the bulk density is too low, it provides a large number of active sites for electrochemical reactions, allowing operation at lower macroscopic current densities, thereby improving reaction efficiency and rate. Porous structures facilitate electrolyte permeation and reactant / product transport, which helps maintain stable reaction interface concentrations. However, electrodes are prone to cracking and pulverization under fluid erosion, gas escape, or thermal stress, leading to shortened electrode life and product contamination. Furthermore, complex pore structures elongate and distort current paths, increasing the overall "effective resistance."

[0030] For example, the bulk density of the porous carbon material is 1.0 g / cm³. 3 1.05g / cm 3 1.2g / cm 3 1.3g / cm 3 and 1.5g / cm 3 Any one of them, or 1.0 g / cm 3 -1.5g / cm 3 Other values ​​within the range.

[0031] It should be noted that by precisely controlling parameters such as voltage, temperature, and porous carbon materials, this invention can regulate the kinetics of the lithium metal crystallization process, thereby achieving control over the product morphology.

[0032] In an optional embodiment, the inert material is selected from at least one of platinum, graphite, and nickel alloys.

[0033] It should be noted that the inert materials selected in the embodiments of the present invention can coexist safely with high-temperature, highly reactive molten chloride salts without significant chemical reactions or physical corrosion, thereby ensuring the purity, controllability and safety of the process.

[0034] In an optional implementation, the electrolysis treatment time is 1-3 hours.

[0035] The electrolysis time can be adjusted reasonably according to the actual amount of material being processed. For example, the time can be selected from any one of 1h, 1.5h, 2h, 2.5h and 3h, or other values ​​within the range of 1h-3h.

[0036] In an optional embodiment, the cathode product is further cleaned with an organic solvent after the electrolytic treatment; The organic solvent is selected from at least one of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

[0037] It should be noted that organic solvent cleaning is mainly used to remove electrolyte ions from the product and improve the purity of the lithium-carbon composite material.

[0038] Specifically, after the electrolysis process, the product generated at the cathode is cooled, and the substance formed on its surface is collected. This substance is then washed in an organic solvent to obtain the lithium-carbon composite material. The collection method is not particularly limited and can be chosen according to actual needs, such as mechanical tapping or peeling off the component.

[0039] In an optional implementation, the temperature is 410°C-430°C.

[0040] It is important to note that the temperature of the electrolytic treatment, i.e., the temperature of the molten electrolytic salt, must be higher than its melting point. This is because only when chloride salts are molten do they possess ionic conductivity, allowing the electrochemical reaction to proceed smoothly. Higher temperatures result in faster ion movement, reducing concentration polarization, increasing current efficiency, and lowering electrolyte resistance, thereby reducing cell voltage and saving energy. However, excessively high temperatures significantly increase energy consumption and cause more severe chemical and physical corrosion to the electrolytic cell lining (refractory material) and electrodes, requiring higher standards and increasing costs.

[0041] For example, the temperature can be selected from any one of 410°C, 415°C, 420°C, 425°C and 430°C, or other values ​​in the range of 410°C to 430°C.

[0042] In an optional embodiment, the electrolytic cell is made of stainless steel and the cell lining is constructed of magnesia bricks or high-alumina bricks; in other embodiments of the invention, other materials may be selected according to actual needs.

[0043] In summary, the preparation method of the lithium-carbon composite material provided in the embodiments of the present invention includes the following steps: The electrolytic cell is made of stainless steel, with an inert material as the anode and a porous carbon material as the cathode. The carbon particle size of the porous carbon material is 1μm-5μm, and the bulk density is 1.0 g / cm³. 3 -1.5 g / cm 3 After adding a certain amount of lithium chloride-potassium chloride electrolyte and heating to melt, the electrolytic cell temperature is controlled at 410℃-430℃, and the current density is 1.0A / cm³. 2 -1.5A / cm 2 After electrolysis for 1-3 hours, a lithium-carbon composite material is obtained. After being removed, it is washed with an organic solvent to remove the residual molten salt on the surface, and then dried and stored.

[0044] Secondly, embodiments of the present invention provide a lithium-carbon composite material, prepared by the aforementioned preparation method, wherein the carbon content is 5 wt.%-35 wt.%.

[0045] Thirdly, embodiments of the present invention provide a lithium battery, including a lithium-carbon composite material prepared by the aforementioned preparation method or a lithium-carbon composite material prepared by the aforementioned method.

[0046] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0047] Example 1 This embodiment provides a method for preparing lithium-carbon composite materials, including the following steps: An electrolytic cell made of stainless steel was used, with a nickel alloy electrode as the anode and graphite as the cathode. The graphite was porous graphite containing carbon nanotubes, with carbon particles of 5 μm in diameter and a bulk density of 1.3 g / cm³. 3 After adding a certain amount of composite chloride electrolyte (lithium chloride-potassium chloride in a 1:1 mass ratio) and heating to fuse it, the electrolytic cell temperature was controlled at 420℃ and the current density at 1.3 A / cm². 2 After electrolysis for 2 hours, lithium-carbon composite materials (such as...) were obtained. Figure 1 As shown in the figure, after removal, wash with the organic solvent dimethyl carbonate (DMC) to remove residual molten salt on the surface, and then dry and store.

[0048] Example 2 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The carbon particles in the carbon nanotubes have a diameter of 3 μm.

[0049] Example 3 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The carbon particles in the carbon nanotubes have a diameter of 1 μm.

[0050] Example 4 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The bulk density is 1.0 g / cm³. 3 .

[0051] Example 5 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The bulk density is 1.5 g / cm³. 3 .

[0052] Example 6 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The current density is 1.0 A / cm². 2 .

[0053] Example 7 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The current density is 1.5 A / cm². 2 .

[0054] Example 8 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The electrolysis time is 1 hour.

[0055] Example 9 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: The electrolysis time is 3 hours.

[0056] Example 10 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: Graphene is chosen as the porous carbon material.

[0057] Example 11 This embodiment provides a method for preparing lithium-carbon composite materials, with the same steps as in Example 1, except that: For porous carbon materials, biochar is the preferred choice.

[0058] Comparative Example 1 This comparative example provides a lithium metal strip material, which is prepared by rolling lithium metal to 200μm to obtain the lithium strip.

[0059] Comparative Example 2 This comparative example provides a method for preparing a lithium-carbon composite material, comprising the following steps: Lithium metal is heated to 200°C in a glove box to form liquid lithium, which is then poured onto a porous carbon matrix (carbon nanotube material) and composited with it. After cooling, a lithium-carbon composite material is obtained.

[0060] Test Example 1 This test example analyzes the carbon content. Specifically, small amounts of lithium-carbon composite materials prepared in Examples 1-11 are taken and measured using an infrared carbon-sulfur analyzer. The analysis results are shown in Table 1.

[0061] Table 1 Experimental conditions and carbon content analysis results

[0062] As can be seen from the data in Table 1, during the electrolytic preparation of lithium-carbon materials, the smaller the particle size of the porous carbon material (Examples 1-3), the lower the carbon content in the resulting lithium-carbon material. This is mainly because smaller particle size results in a larger specific surface area, providing more active sites for electrochemical reactions, and a lower current density per unit area, thus slowing down electrode corrosion. The higher the current density (see Examples 1 and 6-7), the faster the lithium-ion movement rate, the greater the lithium production, and the higher the lithium content in the lithium-carbon material, while the carbon content decreases. However, excessively high current density can lead to more impurities being deposited into the lithium-carbon material. With the increase of electrolysis time (see Examples 1 and 8-9), more lithium is deposited in the porous carbon anode material, and its carbon content decreases. The higher the bulk density (Examples 1 and 4-5), the smaller the porosity of the carbon material, the denser the electrode, the stronger the corrosion resistance, and the lower the carbon content in the lithium-carbon material. Using graphene as the cathode results in an even lower carbon content in the lithium-carbon material, mainly because its structure is more ordered and stable, exhibiting strong corrosion resistance.

[0063] Test Example 2 This test example uses Example 1 as an example to perform appearance photography and SEM morphology analysis on the prepared lithium-carbon composite material; the appearance photography of the lithium-carbon composite material is shown in […]. Figure 1 SEM morphology analysis can be found in Figure 2 .

[0064] Combination Figure 1 and Figure 2 The results show that the lithium-carbon composite material prepared by lithium metal and porous carbon materials has a uniform morphology and no agglomeration.

[0065] Test Example 3 In this test case, the products obtained in Examples 1-11 and Comparative Examples 1-2 were made into standard electrode sheets and assembled into coin cells for performance testing. The relevant data are summarized in Table 2.

[0066] The specific manufacturing method includes: the lithium-carbon composite material obtained in Example 1 and Comparative Example 2 is rolled and pressed to obtain a lithium-carbon composite material strip of a certain thickness, and then cut into electrode sheets with a diameter of 14 mm.

[0067] In addition, the lithium strip in Comparative Example 1 was made into an electrode sheet for electrochemical testing. The specific manufacturing method included cutting the lithium foil into an electrode sheet with a diameter of 14 mm.

[0068] The specific assembly steps include: in an argon glove box, assembling the coin cell in the following order: positive electrode shell, electrode plate, electrolyte, separator, electrode plate, gasket, spring plate, and negative electrode shell.

[0069] The obtained button cells were tested. The impedance test range was 0.01Hz–100kHz, the test condition was 25℃, and the current density for the cyclic test was 0.5mA / cm². 2 The deposition capacity is 0.5 mAh / cm³. 2 The relevant results can be found in [link / reference]. Figures 3-5 Among them, the impedance spectrum of the symmetrical battery before cycling is shown in Figure 3 The impedance spectrum of the symmetrical battery after 100 cycles is shown in [reference needed]. Figure 4 See the symmetrical battery cycle curve. Figure 5 .

[0070] Table 2 Performance Test Data

[0071] As can be seen from the data in Table 2: (1) Electrochemical tests were performed on the lithium-carbon materials in the entire example (1-11). Before cycling, the SEI film impedance value was basically 50Ω-65Ω, and after cycling, the SEI film impedance value was basically 20Ω-30Ω. The stable cycling time was 250 h-280 h. The main reason for the change in the proportion of lithium elements generated and the uniformity of deposition was the difference in the selection of experimental conditions (current density, temperature, electrolysis time, cathode material and various performance parameters). (2) Analysis of Examples 1-11 and Comparative Examples 1 and 2 reveals that the electrochemical data in the examples are significantly better than those in the comparative examples. This is because porous carbon material is used as the cathode, and the tiny carbon particles generated by the corrosion of lithium metal carbon material are combined and encapsulated in situ to generate highly intercalated lithium carbon material. The carbon material restricts the growth of the SEI film to a certain extent, effectively alleviates the volume change, and has better cycle stability. In contrast, no porous carbon was added to Comparative Example 1, so the growth of lithium dendrites could not be restricted. In Comparative Example 2, the lithium carbon mixture was uneven, resulting in a larger impedance.

[0072] from Figure 3 It can be observed that the impedance of Comparative Example 2 (71Ω) is significantly smaller than that of Comparative Example 1 (152Ω). This is because in the lithium-carbon composite material, lithium metal is reactive to the electrolyte and will spontaneously react to form an SEI film, while carbon material is relatively stable to the electrolyte. Therefore, carbon material can limit the growth of the SEI film to a certain extent, making the SEI film on the electrode surface thinner. The impedance of Example 1 (48Ω) is smaller than that of Comparative Example 2. This is because Example 1 uses electrolysis to allow lithium metal to combine and encapsulate tiny carbon particles in situ. This ensures that lithium can be highly uniformly dispersed in the carbon-based material, avoiding the agglomeration of lithium metal.

[0073] from Figure 4 It can be observed that the impedance of Example 1 (21Ω) is less than that of Comparative Example 1 (80Ω) and Comparative Example 2 (35Ω). The decrease in impedance of all three electrodes is due to the formation of a more stable SEI layer on the surface of the negative electrode after cycling. The highly uniformly dispersed lithium metal and carbon material in Example 1 induced Li + Uniform deposition improves Li + This increases the mobility, thereby reducing the electrode interface impedance.

[0074] from Figure 5 It can be observed that Comparative Example 1 exhibits the largest polarization overpotential and short-circuits after 140 hours of cycling. Example 1 remains stable after 140 hours of cycling, and its polarization overpotential is significantly lower than that of Comparative Examples 1 and 2. This is because the highly uniformly dispersed lithium metal and carbon material in Example 1 promotes a uniform current density distribution, reduces polarization, and allows Li... + The deposition is more uniform, and the robust carbon material can also inhibit the growth of lithium dendrites, ensuring stable battery cycling.

[0075] In summary, the lithium-carbon composite material and its preparation method provided by the embodiments of the present invention have the following characteristics: (1) Simple and efficient: The equipment is simple to set up and the production process is short. It is synthesized in one step by molten salt electrolysis, which is easy to industrialize on a large scale. (2) Good uniformity: Lithium is generated on the surface of the carbon cathode or electrolyte, rather than simply mixed. This "atomic-level" mixing ensures that lithium can be highly uniformly dispersed in the carbon-based material, avoiding agglomeration and greatly improving the electrochemical performance of the material; (3) Controllable structure: By precisely controlling parameters such as current density, volume density, temperature and porous carbon materials, the kinetics of the lithium metal crystallization process can be regulated, thereby controlling the microstructure of the product.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a lithium-carbon composite material, characterized in that, Includes the following steps: Using an inert material as the anode, porous carbon material as the cathode, and a composite chloride salt as the electrolyte, the experiment was conducted at a temperature of 380℃-450℃ and a current density of 1.0 A / cm². 2 -1.5A / cm 2 Under certain conditions, an electrolytic process was carried out to obtain a lithium-carbon composite material; The porous carbon material has a carbon particle size of 0.5 μm-10 μm and a bulk density of 0.8 g / cm³. 3 -1.7g / cm 3 ; The complex chloride salt comprises lithium chloride and potassium chloride, wherein the mass percentage of lithium chloride is 45%-55%.

2. The preparation method according to claim 1, characterized in that, The porous carbon material is selected from at least one of carbon nanotubes, graphene, biochar, and anthracite.

3. The preparation method according to claim 1, characterized in that, The carbon particle size of the porous carbon material is 1μm-5μm.

4. The preparation method according to claim 1, characterized in that, The bulk density of the porous carbon material is 1.0 g / cm³. 3 -1.5 g / cm 3 .

5. The preparation method according to claim 1, characterized in that, The inert material is selected from at least one of platinum, graphite, and nickel alloys.

6. The preparation method according to claim 1, characterized in that, The electrolysis treatment time is 1-3 hours.

7. The preparation method according to claim 1, characterized in that, The electrolytic treatment also includes cleaning the cathode products with an organic solvent; The organic solvent is selected from at least one of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

8. The preparation method according to claim 1, characterized in that, The temperature is 410℃-430℃.

9. A lithium-carbon composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-8, wherein the carbon content is 5 wt.%-35 wt.%.

10. A lithium battery, characterized in that, This includes lithium-carbon composite materials prepared by any one of the preparation methods described in claims 1-8 or lithium-carbon composite materials as described in claim 9.

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