Catalytic graphite material and its manufacturing method and use

Abstract

This application provides a catalytic graphite material, as well as a manufacturing method and use thereof. The catalytic graphite material includes sheet graphite and hollow spherical graphite particles, and the catalytic graphite material has a 3R phase. The catalytic graphite material has high purity, a high degree of graphitization, and the 3R phase. The presence of the 3R phase provides more intercalation sites for lithium ions. When used as an anode material for lithium ion batteries, the catalytic graphite material exhibits high capacity, high initial efficiency, and low expansion, significantly improving the electrochemical performance of lithium ion batteries, such as capacity and initial efficiency.

Description

[Technical Field]

[0001] This application is in the field of battery technology and relates to catalytic graphite materials and their methods of manufacture and use. [Background technology]

[0002] Anode materials are the core material of lithium-ion batteries, and graphite anode materials are currently the mainstream anode material and the anode material with the largest production and sales volume. Currently, there are increasing demands for high-performance anode material manufacturing technologies and low-energy consumption, low-cost manufacturing processes. Biomass has notable characteristics, such as a wide range of raw material sources, ecological safety, and pollution-free production. Converting biomass into graphite anode materials as a carbon absorption method not only achieves carbon storage but also reduces dependence on fossil fuels such as coal and oil. Therefore, producing graphite anode materials for energy storage from biomass has significant economic, ecological, and social benefits.

[0003] For example, patent application publication number CN107406259A discloses a method for producing graphite from biomass, which involves hydrothermal reaction of biomass with a transition metal salt catalyst in a high-temperature, high-pressure reactor, dispersing the catalyst to obtain catalyst-loaded hydrothermal carbon, filtering and drying the hydrothermal carbon, graphitizing the hydrothermal carbon using an electromagnetic radiation generator, and finally removing impurities by acid washing, washing with water, and drying to obtain the product. However, the high-temperature, high-pressure method for obtaining hydrothermal carbon and the specialized graphitization equipment limit the mass production and low-cost production of this product.

[0004] Patent application publication number CN102502598A discloses a method for catalytic graphitization of wood powder, using nanometal or metal oxide as a catalyst, uniformly mixing the catalyst with wood powder, and then heat-treating the mixture at 900-1600°C to obtain catalytic graphite material. Because the wood powder is not pretreated in this disclosed method, the space utilization rate of the heat-treatment carbonization equipment is very limited, resulting in low production efficiency and high overall energy consumption. Furthermore, because a large amount of the catalyst contained in the synthesized catalytic graphite is not removed, the catalytic graphite material contains a large amount of magnetic material, making it unusable for lithium-ion batteries.

[0005] Patent application CN109301225A discloses a graphite anode material with a double gradient structure of graphitization degree and pore size, and its manufacture and use. The method requires first obtaining a porous carbon material from anthracite, biochar, petroleum coke, or pitch coke as a carbon source, and the specific surface area of ​​the carbon material must be between 100 and 2000 m. 2 The porous carbon material is immersed in a catalyst solution containing a water-insoluble or water-soluble metal salt, a nanometal, and a water-soluble non-metal salt, with a concentration of 0.01g / g, and the solution is placed in a sealed container, evacuated, and then dried to load the catalyst into the pores of the porous carbon material. This is followed by two-stage electroforging, during which the main components added are pitch and resin, which are amorphous carbon sources, ultimately forming a radially gradient structure. This disclosed method, which involves the activation pore formation process to obtain a porous carbon material, results in the loss of a large amount of carbon element, which not only increases production costs but also reduces the yield of the final graphite material.

[0006] As can be seen, the catalytic graphite materials disclosed in the prior art leave room for improvement in terms of their performance in lithium-ion batteries and lack high purity. For example, silicon impurities contained in biomass or coal-based raw materials typically exist as silicon dioxide and silicates, and remain after catalytic reactions. If not removed, their mass ratio affects the overall gram capacity of the catalytic graphite, thereby reducing the capacity of lithium-ion batteries. Furthermore, the prior art primarily focuses on the conversion rate and graphitization degree of the catalyzed graphite, but does not particularly focus on or ignore the graphite structure necessary for high-performance anode materials in lithium-ion batteries. As a result, the key process of catalyst synthesis is not optimized to meet the graphite structural characteristics required for low expansion, high capacity, and high initial efficiency when used as anode materials in lithium-ion batteries. At the same time, in the production of catalytic graphite, carbon materials must first be activated to convert them into porous carbon materials to facilitate immersion in the catalyst solution before loading them with the catalyst. This activation process not only results in the loss of a large amount of carbon material, but also increases production costs by reducing the yield of the final graphite material. Furthermore, the prior art biomass processing involves high-temperature, high-pressure hydrothermal reactions, and catalytic conversion involves heating with electromagnetic radiation generators, which limits the mass production and low-cost production of the product.

[0007] Based on the above considerations, there is a need to provide a catalytic graphite material that exhibits the advantages of high capacity, high initial efficiency, and low expansion when applied as an anode material in lithium ion batteries. Summary of the Invention [Problem to be solved by the invention]

[0008] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0009] The present application aims to provide a catalytic graphite material with high purity, high degree of graphitization, and 3R phase, as well as a manufacturing method and use thereof. When used as an anode material for lithium-ion batteries, the catalytic graphite material exhibits high capacity, high initial efficiency, and low expansion, significantly improving the electrochemical performance of lithium-ion batteries, such as capacity and initial efficiency. [Means for solving the problem]

[0010] To achieve this object, the present application provides the following technical solutions.

[0011] In a first aspect, the present application provides a catalytic graphite material comprising sheet graphite and hollow spherical graphite particles and having a 3R phase.

[0012] The catalytic graphite material according to the present application has a 3R phase (rhombohedral phase), and the 3R structure of graphite is closely related to the electrochemical property of high capacity of graphite anode materials. The presence of the 3R phase provides more intercalation sites for lithium ions, so the catalytic graphite material has superior electrochemical performance to artificial graphite and natural graphite. At the same time, the present application also includes sheet graphite and hollow spherical graphite, where the sheet graphite has different orientations and forms a pore structure by bending and folding, etc., and when combined with hollow graphite particles, it can provide space for the expansion of the graphite material. The catalytic graphite material has a small specific surface area and low orientation, so the product performance is characterized by a higher initial coulomb and low expansion than catalytic graphite in the prior art.

[0013] In one embodiment, the catalytic graphite material further comprises particle agglomerates and amorphous particles.

[0014] The catalytic graphite material according to the present invention includes lamellar graphite, hollow spherical graphite, particle aggregates, and amorphous particles. The various graphite forms reduce the degree of anisotropy of the catalytic graphite material, thereby exhibiting the advantage of low expansion when applied to the negative electrode material of lithium-ion batteries.

[0015] In one embodiment, the graphitization degree of the catalyst graphite material is g, where 95% ≤ g < 100%, and it may be, for example, 95%, 96%, 97%, 98%, 99% or 99.9%, but is not limited to the recited values, and other unrecited values within the numerical range are equally applicable.

[0016] In one embodiment, the sphericity of the hollow spherical graphite particles is greater than 0.7, and may be, for example, 0.75, 0.8, 0.85, 0.9, but is not limited to the recited values, and other unrecited values within the numerical range are equally applicable.

[0017] The sphericity according to the present application is the ratio of the shortest axis to the longest axis of the particle.

[0018] In one embodiment, the outer diameter of the hollow spherical graphite particles is D, where 5 < D < 50 μm, and it may be, for example, 6 μm, 10 μm, 20 μm, 30 μm, 40 μm or 49 μm, but is not limited to the recited values, and other unrecited values within the numerical range are equally applicable, and preferably 10 < D < 30 μm.

[0019] In one embodiment, the R value of the catalyst graphite material is within the range of 0.03 to 0.4, and may be, for example, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4 or 0.5, but is not limited to the recited values, and other unrecited values within the numerical range are equally applicable, where R value = I D / I G where I D is the peak intensity value of the D peak, and I G is the peak intensity value of the G peak. The Raman shift of the D peak is around 1350 cm -1 and the Raman shift of the G peak is around 1580 cm -1 .

[0020] In one embodiment, the average R value is less than 0.25, and may be, for example, 0.24, 0.2, 0.18, 0.16, 0.14, or 0.12, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0021] In a second aspect, the present application provides a method for producing the catalytic graphite material according to the first aspect, comprising: A step (1) of pre-carbonizing a carbon source to obtain carbon powder, mixing the carbon powder with a catalyst solution, and then performing solid-liquid separation to obtain composite particles carrying a catalyst; and (2) heat-treating the composite particles described in step (1) and then post-treating them to obtain the catalytic graphite material.

[0022] In this application, a carbon source is first pre-carbonized, and the inherent pipe pores or pores formed between the polymer structure of the carbon source remain during the pre-carbonization process, and small molecules overflow during the pre-carbonization process to form fine microchannels. The pre-carbonized carbon powder is then mixed with a catalyst solution, and the catalyst solution fills the pores of the carbon powder, resulting in composite particles with a uniform catalyst loading on both the carbon surface and within the pore structure. Finally, the catalyst is removed by high-temperature heat treatment and post-treatment, resulting in a catalytic graphite material with a purity of 99.9% or more. When used as an anode material for lithium-ion batteries, the resulting catalytic graphite material exhibits high capacity, high initial efficiency, and low expansion.

[0023] In one embodiment, combining the carbon powder with the catalyst solution as described in step (1) comprises vacuum-soaking the carbon powder into the catalyst solution.

[0024] The carbon powder according to the present invention is preferably immersed in the catalytic solution under vacuum conditions, so that the catalytic solution can be fully filled into the pores of the carbon powder, which is advantageous for the efficient and high-quality conversion of the carbon material into catalytic graphite.

[0025] In one embodiment, the vacuum immersion time is 1 to 2.5 hours, for example, 1 hour, 1.5 hours, 2 hours, or 2.5 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range also apply.

[0026] In one embodiment, the mass ratio of the carbon powder to the catalyst solution in step (1) is 1:(4-7), and may be, for example, 1:4, 1:5, 1:6, or 1:7, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0027] When the amount of catalyst according to the present invention is within a reasonable range, the electrochemical performance of the catalytic graphite material can be further improved. If the amount of catalyst is too large, the difficulty of acid washing purification increases, which increases production costs, and the specific surface area of ​​the catalytic graphite is likely to be too large, resulting in poor initial coulombic efficiency of the catalytic graphite material. If the amount of catalyst is too small, the catalytic conversion effect is poor, the catalytic conversion rate is not high, and the catalytic graphite material exhibits poor capacity and initial coulombic efficiency.

[0028] In one embodiment, the mass of material A obtained after the solid-liquid separation in step (1) is 3 to 3.7 times the mass of the carbon powder, for example, 3 times, 3.2 times, 3.4 times, 3.6 times, or 3.7 times, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0029] In one embodiment, the catalyst solution described in step (1) comprises a catalyst and water mass ratio of (1-2):1, which may be, for example, 1:1, 1.5:1, or 2:1, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0030] In one embodiment, the pre-carbonization temperature in step (1) is 500 to 1200°C, and may be, for example, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, or 1200°C, and the pre-carbonization time is 1 to 6 hours, and may be, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range also apply.

[0031] In one embodiment, the pre-carbonization described in step (1) is carried out under a protective gas, and the protective gas comprises any one or a combination of at least two of nitrogen gas, argon gas, krypton gas, or helium gas.

[0032] In one embodiment, the particle size D50 of the carbon powder described in step (1) is 5 to 45 μm, and may be, for example, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, or 45 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range also apply.

[0033] In one embodiment, the method of solid-liquid separation described in step (1) comprises press filtration.

[0034] In one embodiment, the solid-liquid separation in step (1) is followed by further drying, and the drying temperature is 150 to 300°C, for example, 150°C, 200°C, 250°C, or 300°C, and the drying time is 2 to 4 hours, for example, 2 hours, 3 hours, or 4 hours. However, the drying time is not limited to the listed values, and other unlisted values ​​within the range of the value also apply.

[0035] In one embodiment, the catalyst described in step (1) comprises an inorganic salt and / or an organic salt, preferably an inorganic salt and / or an organic salt of any one or a combination of at least two of vanadium, chromium, manganese, iron, cobalt, nickel, or copper, with typical but non-limiting combinations including a combination of vanadium and chromium, and a combination of manganese and iron.

[0036] In one embodiment, the carbon source described in step (1) comprises a biomass carbon source and / or a biomass derivative.

[0037] The carbon source according to the present invention is a carbon-containing biomass raw material having pipe holes and a biomass secondary processed material capable of forming pores.

[0038] In one embodiment, the biomass carbon source comprises a combination of at least one of straw, fruit pits, wood, or bamboo, with typical but non-limiting combinations including a combination of straw and fruit pits, or a combination of wood and bamboo.

[0039] In one embodiment, the biomass secondary material comprises a combination of one or at least two of glucose, sucrose, starch, lignin, cellulose, or hemicellulose, with exemplary, but non-limiting, combinations including glucose and sucrose, and starch and lignin.

[0040] In one embodiment, the composite particles are further isostatically treated prior to the heat treatment described in step (2).

[0041] In the present invention, isostatic treatment is carried out before the heat treatment to further reduce the residual porosity, improving the contact between the catalyst and the carbon, which is beneficial for the catalytic conversion of carbon to graphite material, and also for some of the catalyst to be encased in carbon powder, which can be removed by post-treatment to form graphite hollow spheres.

[0042] In one embodiment, the pressure increase rate of the isostatic treatment is 5 to 100 MPa / min, and may be, for example, 5 MPa / min, 10 MPa / min, 20 MPa / min, 40 MPa / min, 60 MPa / min, 80 MPa / min, or 100 MPa / min, and the pressure is 200 to 400 MPa, and may be, for example, 200 MPa, 300 MPa, or 400 MPa, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0043] In one embodiment, the pressure retention time of the isostatic treatment is 10 to 120 min, and may be, for example, 10 min, 30 min, 50 min, 70 min, 90 min, 110 min, or 120 min, the pressure reduction rate is 5 to 100 MPa / min, and may be, for example, 5 MPa / min, 10 MPa / min, 20 MPa / min, 40 MPa / min, 60 MPa / min, 80 MPa / min, or 100 MPa / min, and the pressure may be 200 to 400 MPa, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0044] In one embodiment, the number of times of the isostatic pressure treatment is two or more, for example, two, three, four, or five times, but is not limited to the recited numbers, and other unrecited integer numbers within the numerical range also apply.

[0045] In the isostatic treatment of the present invention, within a certain pressure range, the higher the peak pressure of the isostatic pressure, the more favorable it is for the catalytic conversion of carbon to graphite. The pressure causes some of the catalyst to be tightly wrapped in carbon powder. During the catalytic conversion process, this carbon is converted to graphite on the catalyst surface, and graphite hollow spheres are obtained after the catalyst is removed. However, if the pressure is too high and exceeds the pressure-bearing capacity of the carbon powder or catalyst, the pressurized material will begin to crack, expand, and pulverize, which is detrimental to the catalytic effect. Furthermore, within the appropriate pressure range, slow pressure increase, extended pressure dwell time, slow pressure release, and multiple isostatic pressure processes are all favorable for the subsequent catalytic conversion of carbon to graphite.

[0046] In one embodiment, the temperature of the heat treatment described in step (2) is 1300 to 1900°C, for example, 1300°C, 1500°C, 1700°C, or 1900°C, and the time is 1 to 5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range also apply.

[0047] In one embodiment, the post-treatment described in step (2) comprises pickling, water washing and drying, performed in sequence.

[0048] In one embodiment, the pickling solution used for the pickling contains hydrochloric acid and / or hydrofluoric acid.

[0049] In one embodiment, the concentration of the hydrochloric acid is 0.8 to 1.2 mol / L, and may be, for example, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, or 1.2 mol / L, and the concentration of the hydrofluoric acid is 0.3 to 0.7 mol / L, and may be, for example, 0.3 mol / L, 0.5 mol / L, or 0.7 mol / L, but is not limited to these numerical values, and other unrecited numerical values ​​within the numerical ranges also apply.

[0050] In one embodiment, the drying temperature is 150 to 300°C, for example, 150°C, 200°C, 250°C, or 300°C, and the drying time is 0.5 to 3 hours, for example, 0.5 hours, 1 hour, 2 hours, or 3 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range also apply.

[0051] As a preferred technical solution of the manufacturing method according to the present application, the manufacturing method comprises: Step (1) of pre-carbonizing a carbon source under a protective gas at a temperature of 500 to 1200°C for 1 to 6 hours to obtain carbon powder having a particle size D50 of 5 to 45 μm, then immersing the carbon powder in a catalyst solution under vacuum for 1 to 2.5 hours, and then press-filtering the filtered cake, and drying the filtered cake at 150 to 300°C for 2 to 4 hours to obtain composite particles carrying a catalyst, wherein the mass ratio of the carbon powder to the catalyst solution is 1:(4 to 7); and step (2) of pressurizing the composite particles described in step (1) to 200 to 400 MPa at a pressure increase rate of 5 to 100 MPa / min, subjecting them to isostatic pressure treatment for 10 to 120 minutes, and releasing the pressure at a pressure decrease rate of 5 to 100 MPa / min to obtain a hydrostatic material, which is then heat-treated at a temperature of 1300 to 1900°C for 1 to 5 hours, and then sequentially pickling, rinsing with water, and drying to obtain the catalytic graphite material.

[0052] In a third aspect, the present application provides a lithium ion battery comprising the catalytic graphite material according to the first aspect. [Effects of the Invention]

[0053] Compared with the prior art, the present application has the following beneficial effects:

[0054] The catalytic graphite material of the present application has a 3R phase and includes sheet graphite and hollow spherical graphite. The combination of sheet graphite and hollow graphite provides the catalytic graphite material with superior electrochemical performance compared to artificial graphite, natural graphite, and conventional catalytic graphite materials. Therefore, when the catalytic graphite material of the present application is used as an anode material for lithium-ion batteries, it exhibits advantages such as high capacity, high initial efficiency, and low expansion. At the same time, the present application improves the manufacturing method by densifying the catalyst and carbon powder to obtain higher-quality biomass graphite, thereby achieving true carbon recycling and carbon fixation effects in the new energy field.

[0055] Other aspects will become apparent upon reading and understanding the drawings and detailed description. [Brief explanation of the drawings]

[0056] The drawings are used to provide a further understanding of the technical solutions of the present specification, constitute a part of the specification, and are used to interpret the technical solutions of the specification together with the embodiments of the present application, but are not intended to limit the technical solutions of the specification.

[0057] [Figure 1] FIG. 2 is an SEM image of carbon powder according to Example 1 of the present application. [Figure 2] FIG. 2 is an SEM image of a composite particle according to Example 1 of the present application. [Figure 3] FIG. 2 is an SEM image of a cross section of a composite particle according to Example 1 of the present application. [Figure 4] FIG. 1 is a mapping diagram of C in a composite particle according to Example 1 of the present application. [Figure 5]FIG. 1 is a mapping diagram of Ni in composite particles according to Example 1 of the present application. [Figure 6] FIG. 1 is an XRD diagram of the catalytic graphite material according to Example 1 of the present application, with 2θ in the range of 20 to 80°. [Figure 7] FIG. 1 is an XRD diagram of the catalytic graphite material according to Example 1 of the present application, in which 2θ is in the range of 40 to 48°. [Figure 8] FIG. 1 is an XRD diagram of the catalytic graphite material according to Example 1 of the present application, with 2θ in the range of 52 to 80°. [Figure 9] 1 shows 2D Raman imaging by laser Raman spectroscopic area scanning and corresponding optical diagrams of a catalytic graphite material according to Example 1 of the present application. [Figure 10] FIG. 2 is an SEM image of sheet graphite in the catalytic graphite material according to Example 1 of the present application. [Figure 11] FIG. 2 is an SEM image of hollow spherical graphite particles in the catalytic graphite material according to Example 1 of the present application. [Figure 12] FIG. 2 is an SEM image of particle aggregates in the catalytic graphite material according to Example 1 of the present application. [Figure 13] FIG. 2 is an SEM image of amorphous particles in the catalytic graphite material according to Example 1 of the present application. [Figure 14] FIG. 2 is an SEM image of hollow spherical graphite particles after fracture in the catalytic graphite material according to Example 1 of the present application. [Figure 15] FIG. 1 is a cross-sectional view of a catalytic graphite material according to Example 1 of the present application. [Figure 16] 1 is a charge / discharge graph of a battery made from the catalytic graphite material according to Example 1 of the present application. [Figure 17] 10 is a charge / discharge graph of a battery made from the catalytic graphite material according to Example 5 of the present application. [Figure 18] 10 is a charge / discharge graph of a battery made from the catalytic graphite material according to Example 7 of the present application. [Figure 19] FIG. 2 is a cross-sectional SEM image of an artificial graphite material according to Comparative Example 2 of the present application. [Figure 20] FIG. 2 is an XRD diagram of the artificial graphite material according to Comparative Example 2 of the present application, in which 2θ is in the range of 20 to 80°. [Figure 21]FIG. 2 is an XRD diagram of the artificial graphite material according to Comparative Example 2 of the present application, in which 2θ is in the range of 40 to 48°. [Figure 22] FIG. 2 is an XRD diagram of the artificial graphite material according to Comparative Example 2 of the present application, in which 2θ is in the range of 52 to 80°. [Figure 23] FIG. 2 is an SEM image of a 500 μm scale of a sheet-shaped graphite material according to Comparative Example 3 of the present application. [Figure 24] FIG. 2 is an SEM image of a sheet-shaped graphite material according to Comparative Example 3 of the present application, at a scale of 20 μm. [Figure 25] FIG. 2 is an XRD diagram of the sheet-shaped graphite material according to Comparative Example 3 of the present application, in which 2θ is in the range of 20 to 80°. [Figure 26] FIG. 2 is an XRD diagram of the sheet-shaped graphite material according to Comparative Example 3 of the present application, in which 2θ is in the range of 40 to 48°. [Figure 27] FIG. 2 is an XRD diagram of the sheet-shaped graphite material according to Comparative Example 3 of the present application, in which 2θ is in the range of 52 to 80°. [Figure 28] FIG. 1 is an XRD diagram of the catalytic graphite material according to Example 1 of the present application and the sheet-like graphite material according to Comparative Example 3, with 2θ in the range of 12 to 32°. [Figure 29] FIG. 2 is an SEM image of a spherical natural graphite material according to Comparative Example 4 of the present application. [Figure 30] FIG. 2 is a cross-sectional SEM image of a spherical natural graphite material according to Comparative Example 4 of the present application. [Figure 31] FIG. 2 shows Raman 2D imaging by laser Raman spectroscopic area scanning and the corresponding optical diagram of a spherical natural graphite material according to Comparative Example 4 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0058] The technical solution of the present application will be further described below through specific embodiments, which are merely for those skilled in the art to understand the present application and should not be regarded as specific limitations on the present application. [Example]

[0059] This example provided a catalytic graphite material having a 3R phase and including sheet graphite, hollow spherical graphite particles, particle agglomerates, and amorphous particles.

[0060] The method for producing the catalytic graphite material includes the following steps:

[0061] (1) Corn straw was pre-carbonized under nitrogen gas at 900°C for 1 hour and crushed to obtain carbon powder with a particle size D50 of 45 μm. The carbon powder was then vacuum-immersed in a catalyst solution for 1 hour, and then press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighing revealed that the mass of Material A was 3.7 times the mass of the carbon powder, i.e., the mass ratio of carbon powder to catalyst solution was 1:2.7. The mixture was then dried at 300°C for 2 hours to obtain composite particles carrying the catalyst.

[0062] The mass ratio of the carbon powder to the catalyst solution is 1:5, and the catalyst solution contains nickel chloride and water in a mass ratio of 1.8:1.

[0063] (2) The composite particles from step (1) were subjected to isostatic pressure treatment at a pressure increase rate of 5 MPa / min to 350 MPa for 120 minutes, and then the pressure was released at a pressure decrease rate of 5 MPa / min to obtain a hydrostatic material. The hydrostatic material was then heat-treated at a temperature of 1900°C for 1 hour. After that, it was pickled with a mixture of 1 mol / L hydrochloric acid and 0.5 mol / L hydrofluoric acid, filtered, and washed with water. Finally, it was dried at 200°C for 2 hours to obtain the catalytic graphite material.

[0064] The SEM image of the carbon powder of this example is shown in Figure 1, the SEM image of the composite particle is shown in Figure 2, the SEM image of the cross section of the composite particle is shown in Figure 3, the mapping image of C in the composite particle is shown in Figure 4, and the mapping image of Ni is shown in Figure 5. The XRD patterns of the catalytic graphite material within the 2θ range of 20 to 80° are shown in FIG. 6, the XRD patterns within the 2θ range of 40 to 48° are shown in FIG. 7, and the XRD patterns within the 2θ range of 52 to 80° are shown in FIG. 8. Raman 2D imaging by laser Raman spectroscopic area scanning and the corresponding optical diagram are shown in FIG. 9. An SEM image of sheet graphite in the catalytic graphite material is shown in FIG. 10. An SEM image of hollow spherical graphite particles is shown in FIG. 11. An SEM image of particle aggregates is shown in FIG. 12. An SEM image of amorphous particles is shown in FIG. 13. An SEM image of hollow spherical graphite particles after rupture is shown in FIG. 14. A cross-sectional morphology diagram of the catalytic graphite material is shown in FIG. 15. A charge / discharge graph of the catalytic graphite material after being used in a battery is shown in FIG. 16. An XRD pattern within the 2θ range of 12 to 32° is shown in FIG. 28. [Example]

[0065] This example provided a catalytic graphite material having a 3R phase and including sheet graphite, hollow spherical graphite particles, particle agglomerates, and amorphous particles.

[0066] The method for producing the catalytic graphite material includes the following steps:

[0067] (1) Soybean straw was pre-carbonized under nitrogen gas at 1200°C for 2 hours and crushed to obtain carbon powder with a particle size D50 of 37 μm. The carbon powder was then vacuum-immersed in a catalyst solution for 1.5 hours and then press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighing revealed that the mass of Material A was 3.3 times the mass of the carbon powder, i.e., the mass ratio of carbon powder to catalyst solution was 1:2.3. The mixture was then dried at 250°C for 2.5 hours to obtain composite particles carrying the catalyst.

[0068] The mass ratio of the carbon powder to the catalyst solution is 1:5, and the catalyst solution contains cobalt chloride and water in a mass ratio of 1:1.

[0069] (2) The composite particles from step (1) were subjected to isostatic pressure treatment at a pressure increase rate of 50 MPa / min to 400 MPa for 120 minutes, and then the pressure was released at a pressure decrease rate of 50 MPa / min to obtain a hydrostatic material. The hydrostatic material was then heat-treated at a temperature of 1700°C for 3 hours. After that, it was pickled with a mixture of 0.8 mol / L hydrochloric acid and 0.7 mol / L hydrofluoric acid, filtered, and washed with water. Finally, it was dried at 250°C for 1 hour to obtain the catalytic graphite material. [Example]

[0070] This example provided a catalytic graphite material having a 3R phase and including sheet graphite, hollow spherical graphite particles, particle agglomerates, and amorphous particles.

[0071] The method for producing the catalytic graphite material includes the following steps:

[0072] (1) Coconut shells were pre-carbonized under nitrogen gas at 800°C for 2 hours and crushed to obtain carbon powder with a particle size D50 of 25 μm. The carbon powder was then vacuum-immersed in a catalyst solution for 2 hours, and then press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighing revealed that the mass of material A was three times the mass of the carbon powder, i.e., the mass ratio of carbon powder to catalyst solution was 1:2.0. The material was then dried at 150°C for 4 hours to obtain composite particles carrying the catalyst.

[0073] The mass ratio of the carbon powder to the catalyst solution is 1:6, and the catalyst solution contains iron chloride and water in a mass ratio of 1:1.

[0074] (2) The composite particles from step (1) were subjected to isostatic pressure treatment for 60 minutes, increasing the pressure to 200 MPa at a pressure increase rate of 10 MPa / min, and then releasing the pressure at a pressure decrease rate of 5 MPa / min, to obtain a hydrostatic material. The hydrostatic material was then heat-treated at a temperature of 1300°C for 4 hours. After that, it was pickled with a mixture of 1 mol / L hydrochloric acid and 0.5 mol / L hydrofluoric acid, filtered, and washed with water. Finally, it was dried at 300°C for 0.5 hours, and the catalytic graphite material was obtained. [Example]

[0075] This example provided a catalytic graphite material having a 3R phase and including sheet graphite, hollow spherical graphite particles, particle agglomerates, and amorphous particles.

[0076] The method for producing the catalytic graphite material includes the following steps:

[0077] (1) Zelkova was pre-carbonized under argon gas at 600°C for 3 hours and crushed to obtain carbon powder with a particle size D50 of 20 μm. The carbon powder was then vacuum-immersed in a catalyst solution for 2 hours and then press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighing revealed that the mass of Material A was 3.2 times the mass of the carbon powder, i.e., the mass ratio of carbon powder to catalyst solution was 1:2.2. The mixture was then dried at 150°C for 4 hours to obtain composite particles carrying the catalyst.

[0078] The mass ratio of the carbon powder to the catalyst solution is 1:4, and the catalyst solution contains iron nitrate and water in a mass ratio of 1.5:1.

[0079] (2) The composite particles from step (1) were subjected to isostatic pressure treatment, increasing the pressure to 250 MPa at a rate of 50 MPa / min for 10 minutes, and then releasing the pressure at a rate of 50 MPa / min to obtain a hydrostatic material. The hydrostatic material was then heat-treated at 1500°C for 3 hours. After that, it was pickled with a mixture of 1.2 mol / L hydrochloric acid and 0.3 mol / L hydrofluoric acid, filtered, and washed with water. Finally, it was dried at 150°C for 3 hours to obtain the catalytic graphite material. [Example]

[0080] This example provided a catalytic graphite material having a 3R phase and including sheet graphite, hollow spherical graphite particles, particle agglomerates, and amorphous particles.

[0081] The method for producing the catalytic graphite material includes the following steps:

[0082] (1) Poplar wood was pre-carbonized under nitrogen gas at 700°C for 3 hours and crushed to obtain carbon powder with a particle size D50 of 9 μm. The carbon powder was then vacuum-immersed in a catalyst solution for 2.5 hours, after which it was press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighing revealed that the mass of Material A was 3.4 times the mass of the carbon powder, i.e., the mass ratio of carbon powder to catalyst solution was 1:2.4. The mixture was then dried at 150°C for 4 hours to obtain composite particles carrying the catalyst.

[0083] The mass ratio of the carbon powder to the catalyst solution is 1:7, and the catalyst solution contains cobalt sulfate and water in a mass ratio of 1:1.

[0084] (2) The composite particles from step (1) were subjected to isostatic pressure treatment for 30 minutes, increasing the pressure to 250 MPa at a pressure increase rate of 20 MPa / min, and then releasing the pressure at a pressure decrease rate of 20 MPa / min, to obtain a hydrostatic material. The hydrostatic material was then heat-treated at a temperature of 1300°C for 4 hours. After that, it was pickled with a mixture of 1 mol / L hydrochloric acid and 0.5 mol / L hydrofluoric acid, filtered, and washed with water. Finally, it was dried at 150°C for 3 hours, and the catalytic graphite material was obtained.

[0085] FIG. 17 shows a charge / discharge graph of a battery made from the catalytic graphite material according to this example. [Example]

[0086] This example provided a catalytic graphite material having a 3R phase and including sheet graphite, hollow spherical graphite particles, particle agglomerates, and amorphous particles.

[0087] The method for producing the catalytic graphite material includes the following steps:

[0088] (1) Bamboo was pre-carbonized under nitrogen gas at 700°C for 4 hours and crushed to obtain carbon powder with a particle size D50 of 43 μm. The carbon powder was then vacuum-immersed in a catalyst solution for 1 hour and then press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighing revealed that the mass of Material A was 3.1 times the mass of the carbon powder, i.e., the mass ratio of carbon powder to catalyst solution was 1:2.1. The mixture was then dried at 200°C for 3 hours to obtain composite particles carrying the catalyst.

[0089] The mass ratio of the carbon powder to the catalyst solution is 1:5, and the catalyst solution contains cobalt chloride, nickel chloride and water in a mass ratio of 1:1:1.

[0090] (2) The composite particles from step (1) were subjected to isostatic pressure treatment at a pressure increase rate of 100 MPa / min to 400 MPa for 60 minutes, and then the pressure was released at a pressure decrease rate of 100 MPa / min to obtain a hydrostatic material. The hydrostatic material was then heat-treated at a temperature of 1700°C for 5 hours. After that, it was pickled with a mixture of 1 mol / L hydrochloric acid and 0.5 mol / L hydrofluoric acid, filtered, and washed with water. Finally, it was dried at 150°C for 3 hours to obtain the catalytic graphite material. [Example]

[0091] This example provided a catalytic graphite material having a 3R phase and including sheet graphite, hollow spherical graphite particles, particle agglomerates, and amorphous particles.

[0092] The method for producing the catalytic graphite material includes the following steps:

[0093] (1) Lignin was pre-carbonized under argon gas at 500°C for 6 hours and crushed to obtain carbon powder with a particle size D50 of 5 μm. The carbon powder was then vacuum-immersed in a catalyst solution for 2 hours, and then press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighing revealed that the mass of material A was 3.4 times the mass of the carbon powder, i.e., the mass ratio of carbon powder to catalyst solution was 1:2.4. The mixture was then dried at 200°C for 4 hours to obtain composite particles carrying the catalyst.

[0094] The mass ratio of the carbon powder to the catalyst solution was 1:5, and the catalyst solution contained cobalt chloride, nickel chloride, iron chloride and water in a mass ratio of 0.6:0.6:0.6:1.

[0095] (2) The composite particles from step (1) were pressurized to 350 MPa at a pressure increase rate of 5 MPa / min and subjected to isostatic pressure treatment for 120 minutes. The pressure was then released at a pressure decrease rate of 5 MPa / min, and the isostatic treatment was repeated once more to obtain a hydrostatic material. The hydrostatic material was then heat-treated at a temperature of 1900°C for 2 hours. After that, it was pickled with a mixture of 1 mol / L hydrochloric acid and 0.5 mol / L hydrofluoric acid, filtered, and washed with water. Finally, it was dried at 150°C for 3 hours to obtain the catalytic graphite material.

[0096] FIG. 18 shows a charge / discharge graph of a battery made from the catalytic graphite material according to this example. [Example]

[0097] This example provides a catalytic graphite material, which is similar to that of Example 1, except that in the preparation method, the vacuum immersion in step (1) is replaced by mechanical stirring, thereby changing the applicability of the resulting catalytic graphite material.

[0098] Specifically, the mechanical stirring included the following steps: the carbon powder and catalyst solution were stirred at a stirring speed of 60 rpm for 1 hour, and then press-filtered. Material A containing the catalyst solution was obtained by press-filtering, and weighed to find that the mass of Material A was 2.6 times the mass of the carbon powder, i.e., the mass ratio of the carbon powder to the catalyst solution was 1:1.6. [Example]

[0099] This example provides a catalytic graphite material, which is the same as that of Example 1, except that in the manufacturing method, the heat treatment temperature in step (2) is set to 1100°C, thereby changing the adaptability of the resulting catalytic graphite material. [Example]

[0100] This example provides a catalytic graphite material, which is the same as that of Example 1, except that the temperature of the heat treatment in step (2) in the preparation method is 2100°C, and the adaptability of the obtained catalytic graphite material is changed. [Example]

[0101] This example provides a catalytic graphite material, which is similar to Example 1, except that in the preparation method, pickling is not performed in step (2), and the adaptability of the obtained catalytic graphite material is changed. [Example]

[0102] This example provides a catalytic graphite material, which is similar to Example 1, except that the isostatic treatment in step (2) of the preparation method is omitted, thereby changing the applicability of the resulting catalytic graphite material. [Example]

[0103] This example provides a catalytic graphite material, which is the same as that in Example 1, except that in the preparation method, the pressure is increased to 100 MPa in step (2), thereby changing the applicability of the resulting catalytic graphite material. [Example]

[0104] This example provides a catalytic graphite material, which is the same as that in Example 1, except that the pressure in step (2) of the preparation method is increased to 500 MPa, thereby changing the applicability of the resulting catalytic graphite material. [Example]

[0105] This example provides a catalytic graphite material, which is similar to Example 1, except that the pre-carbonization step (1) in the preparation method is omitted, thereby changing the applicability of the resulting catalytic graphite material.

[0106] This comparative example provides a carbon material, which is the same as Example 1, except that nickel chloride is not added in the preparation process, which changes the adaptability of the resulting carbon material.

[0107] In this comparative example, an artificial graphite material was provided, and the manufacturing method of the artificial graphite material includes the following steps:

[0108] (1) Soot-based needle raw coke was crushed into coke dust with a particle size D50 of 10 μm.

[0109] (2) The coke dust from step (1) was graphitized in a graphitization furnace, the graphitization temperature was 3000°C, the time was 10 hours, and the material was cooled to room temperature to obtain an artificial graphite material.

[0110] The cross-sectional SEM image of the artificial graphite material according to this comparative example is shown in Figure 19, the XRD pattern within the 2θ range of 20 to 80° is shown in Figure 20, the XRD pattern within the 2θ range of 40 to 48° is shown in Figure 21, and the XRD pattern within the 2θ range of 52 to 80° is shown in Figure 22. Comparative Example 3

[0111] In this comparative example, a sheet-shaped natural graphite material was provided. The method for producing the natural graphite material included the following steps:

[0112] (1)-195 Sheet natural graphite was purified by a mixed acid solution prepared by mixing aqua regia and 5 mol / L hydrofluoric acid solution in a mass ratio of 2:1.

[0113] (2) The acid-washed sheet-shaped natural graphite was washed with water and dried at a drying temperature of 300°C for 0.5 hours to obtain the sheet-shaped natural graphite material.

[0114] The sheet-form graphite material has an SEM image at a 500 μm scale shown in FIG. 23, an SEM image at a 20 μm scale shown in FIG. 24, an XRD image within the 20 to 80° range shown in FIG. 25, an XRD image within the 40 to 48° range shown in FIG. 26, an XRD image within the 52 to 80° range shown in FIG. 27, and an XRD image within the 2θ range of 12 to 32° shown in FIG. 28. Comparative Example 4

[0115] In this comparative example, a spherical natural graphite material was provided. The method for producing the spherical natural graphite material includes the following steps:

[0116] (1) The -195 sheet-like natural graphite after flotation was crushed to a size of 16 μm in Dv50, and then subjected to a spheroidizing treatment in a spheroidizing machine to obtain spherical natural graphite.

[0117] (2) The spherical natural graphite was purified with a mixed acid. The mixed acid solution was prepared by mixing aqua regia and a 5 mol / L hydrofluoric acid solution in a mass ratio of 2:1.

[0118] (3) The spherical natural graphite purified by acid washing was washed with water and dried at a drying temperature of 300°C for 0.5 hours to obtain the spherical natural graphite material.

[0119] The spherical natural graphite material is shown in an SEM image in FIG. 29, a cross-sectional SEM image in FIG. 30, and a Raman 2D imaging by laser Raman spectroscopy area scanning and a corresponding optical diagram in FIG.

[0120] Tests were carried out on the materials obtained in the above examples and comparative examples. The tests included the following:

[0121] (1) XRD spectrum scanning was performed on the sample. The X-ray diffraction instrument used a copper target with a wavelength of 0.154056 nm and a scanning speed of approximately 4° / min. Spectral information was acquired using analysis software such as HighScore Plus and Jade. The graphite orientation was determined by the ratio of the peak intensities of the (004) peak at around 54.5° and the (110) peak at around 77.7°. The graphite orientation was determined by the ratio of the peak intensities of the (004) peak at around 54.5° and the (110) peak at around 77.7°. 004 / I 110 is.

[0122] (2) The morphology of the samples was observed using a scanning electron microscope.

[0123] (3) The sample was measured using a laser Raman spectrometer, with the basic principle of Raman detection being to avoid damaging or burning the sample. Here, the laser wavelength was 532 nm. A selected area of ​​the sample was scanned using the Raman surface scanning function, which is Raman 2D imaging. This area actually consisted of 400 single-point Raman spectra. The R values ​​of the 400 single-point laser Raman spectra were calculated using the device's built-in function, and a color cloud map of the distribution of the R values ​​of the measurement area was obtained. A color bar on the right side of the cloud map showed the R values ​​represented by different colors in the cloud map, and the average value and standard deviation were calculated. The above R=I D / I G and I D is the peak intensity value of the D peak, and I G is the peak intensity value of the G peak, and the Raman shift of the D peak is 1350 cm -1 The Raman shift of the G peak is around 1580 cm -1 It's nearby.

[0124] (4) The samples were cut with an argon ion beam and polished to prepare specimens, and the cross-sectional structure of the samples was observed using a scanning electron microscope.

[0125] (5) The graphitization degree of the samples was measured according to the method described in GB / T 24533-2019.

[0126] (6) The initial coulombic efficiency and initial lithium release / intercalation capacity of the sample were measured as follows. A slurry was prepared using a mass ratio of graphite anode material: CMC: SP: SBR = 93.5:1.5:2:3, then coated, dried, and roll-pressed to obtain anode pieces. CR2430-type button half cells were then fabricated, with a counter electrode consisting of a metallic lithium sheet. The initial lithium insertion capacity, lithium release capacity, and initial coulombic efficiency of the graphite anode material were tested. The button half cells were discharged at 0.1 C to 0.005 V, allowed to stand for 10 min, discharged at 0.01 C to 0.005 V, allowed to stand for 10 min, and then charged at 0.1 C to 2 V. The initial lithium insertion capacity and lithium release capacity were obtained in this manner. The ratio of the initial lithium release capacity to the lithium insertion capacity was the initial coulombic efficiency.

[0127] (7) The specific surface area of ​​the samples was measured according to the specifications of GB / T 19587.

[0128] (8) The true density of the samples was measured according to the method described in GB / T 24533-2019.

[0129] (9) The ash content of the samples was measured according to the method described in YS / T 63.19-2012.

[0130] Measured I 004 / I 110 , graphitization degree, R value, initial lithium release capacity, initial coulombic efficiency, BET, true density and ash content are shown in the table below. [Table 1]

[0131] From Table 1 and the drawings, the following can be seen:

[0132] (1) Figure 1 reveals the characteristic structure of the biocarbon and its natural channels. Figure 2 reveals that the catalyst was uniformly dispersed on the surface and in the channels of the biocarbon. Figure 5 reveals that the catalyst was uniformly dispersed in the pores inside the biocarbon. Figures 6-8 show that a clear 3R phase was present near 43.3° and 46.1°. The orientation obtained from the peak intensity ratio of (004) to (110) was 1.77. The low orientation is due to the overall low orientation of the graphite sheet layer during sample measurement, resulting from the presence of graphite spheres, clusters agglomerated from small particles, and amorphous graphite particles in the catalytic graphite. Figure 9 shows the distribution of the R values, with a low overall R value, a high graphite conversion rate, and a uniform structure. Figures 10-13 show that some particles have a sheet-like morphology similar to that of natural graphite sheets, and there are also spherical graphite particles, clusters agglomerated from small particles, and other amorphous-shaped particles. Figure 14 demonstrates that the hollow spherical graphite particles have a non-solid structure. Figure 15 shows that the graphite spheres have a hollow structure, and the catalytic graphite also contains pores formed by different orientations, curvatures, and rearrangements of the graphite sheet layers. Figure 19 shows that the interior of the artificial graphite material particles is dense. Figures 20-22 show that the artificial graphite material does not have a 3R phase near 43.3° and 46.1°, and the orientation obtained from the ratio of the (004) to (110) peak intensities is 9.48. Figures 25-27 show that the sheet graphite material has a 3R phase near 43.3° and 46.1°, and the orientation obtained from the ratio of the (004) to (110) peak intensities is 139.5. Figure 28 shows that the peak intensity of the (002) peak near 26.4° for the sheet graphite is significantly higher than that for the catalytic graphite material. As can be seen from FIG. 31, the R values ​​in the R value distribution in the figure are all large, and are clearly larger than the measurement results for the catalytic graphite material.

[0133] (2) The catalytic graphite material of the present invention has a 3R phase, which provides more intercalation sites for lithium ions. As can be seen from Examples 1 to 7, increasing the catalyst ratio and heat treatment temperature is beneficial for improving the capacity, initial efficiency, and degree of graphitization of the catalytic graphite material. As can be seen from the SEM morphology image of the carbon powder in Example 1, biocarbon has a distinct natural channel and pore structure, which provides favorable conditions for uniform catalyst dispersion. Furthermore, the catalytic graphite material of the present invention has a low degree of orientation, which tends to cause isotropic expansion during the charge and discharge process, resulting in low expansion characteristics. As can be seen from Examples 1 and 8, the vacuum immersion process is advantageous for immersing the catalyst solution into the pores of the carbon material, thereby contributing to high-efficiency and high-quality conversion of the carbon material to catalytic graphite.

[0134] (3) As can be seen from Examples 1 and 9-10, if the heat treatment temperature is too low, the catalyst cannot effectively convert the carbon material into catalytic graphite, resulting in a low true density, a high specific surface area, and low capacity and initial efficiency of the catalytic graphite anode material. Similarly, if the heat treatment temperature is too high, the performance of the material is also affected. As can be seen from Examples 1 and 11, without acid washing, the presence of impurities resulted in a high ash content, a high true density, and a low capacity. As can be seen from Examples 1 and 12-14, the isostatic treatment and the pressure of the isostatic treatment affect the performance of the material. By performing isostatic treatment within a reasonable pressure range, some of the catalyst is tightly wrapped in carbon powder. During the catalytic conversion process, this carbon is converted to graphite on the catalyst surface. After removing the catalyst by acid washing, graphite hollow spheres can be obtained. As can be seen from Examples 1 and 15, without pre-carbonization, the carbon material shrinks significantly during the catalytic heat treatment process, and the volatile content is high, resulting in poor catalytic effect, specifically, a large surface area, a low capacity, and a low initial efficiency. In addition, the space utilization rate of the heat treatment device is very limited, resulting in low production efficiency and high overall energy consumption.

[0135] (4) As can be seen from Example 1 and Comparative Example 1, without the addition of a catalyst, graphite conversion could not be achieved under high-temperature carbonization conditions, resulting in low capacity and low initial efficiency of the composite anode material, which indicates that the addition of a catalyst is a requirement for converting carbon materials into graphite materials. As can be seen from Example 1 and Comparative Example 2, the catalytic graphite has a 3R phase (rhombohedral phase), while the artificial graphite does not have a 3R phase (rhombohedral phase). The cross-sectional structure of the catalytic graphite material has a pore structure and hollow graphite spheres formed by different orientations, curvatures, and rearrangements of the graphite sheet layers. The cross-section of the artificial graphite has a dense structure, and the graphitization degree of the catalytic graphite is higher than that of the artificial graphite. As can be seen from Example 1 and Comparative Example 3, the natural graphite has a high degree of crystallinity, a more pronounced layered structure, a smaller interlayer distance, and the peak intensity of the (002) peak at about 26.4° in the XRD spectrum is clearly higher than the peak intensity of the (002) peak at about 26.4° in the XRD spectrum of the catalytic graphite. The sheet-like natural graphite in Comparative Example 3 is mainly composed of graphite particles with a sheet-like structure, and the particle morphology of the catalytic graphite contains graphite particles with a hollow spherical structure, clusters formed by agglomeration of small particles, and amorphous graphite particles in addition to some particles having a sheet-like structure similar to natural graphite, so the orientation of the catalytic graphite material is clearly lower than that of the sheet-like natural graphite material. As can be seen from Example 1 and Comparative Example 4, the cross section of spherical natural graphite has a pore structure but no hollow graphite spheres, whereas the catalytic graphite material contains graphite particles with a hollow spherical structure, and the average R value of the catalytic graphite obtained by Raman surface scanning is smaller than the average R value of the spherical natural graphite obtained by Raman surface scanning.

[0136] In summary, the present application provides a catalytic graphite material with high purity, high degree of graphitization, and 3R phase, as well as a manufacturing method and use thereof. When used as an anode material for lithium ion batteries, the catalyzed graphite material exhibits the characteristics of high capacity, high initial efficiency, and low expansion, and significantly improves the electrochemical performance of lithium ion batteries, such as the capacity and initial efficiency.

[0137] The above are merely specific embodiments of the present application, and the scope of protection of the present application is not limited thereto. It should be understood that any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application are all included in the scope of protection and disclosure of the present application.

Claims

1. A catalytic graphite material comprising sheet-like graphite and hollow spherical graphite particles and having a 3R phase.

2. the catalytic graphite material further comprises particle agglomerates and amorphous particles; The degree of graphitization of the catalytic graphite material is g, and 95%≦g<100%; The catalytic graphite material has an R value in the range of 0.03 to 0.4, where R value = I Ｄ / I Ｇ and 2. The catalytic graphite material of claim 1, wherein the hollow spherical graphite particles have an outer diameter D, where 5<D<50 μm.

3. A method for producing the catalytic graphite material according to claim 1 or 2, comprising: A step (1) of pre-carbonizing a carbon source to obtain carbon powder, mixing the carbon powder with a catalyst solution, and then performing solid-liquid separation to obtain composite particles carrying a catalyst; and (2) heat-treating the composite particles according to step (1) and then post-treating them to obtain the catalytic graphite material.

4. In step (1), mixing the carbon powder with the catalyst solution includes vacuum-immersing the carbon powder in the catalyst solution; The vacuum immersion time is 1 to 2.5 hours, The mass ratio of the carbon powder to the catalyst solution described in step (1) is 1:(4-7); The method according to claim 3, wherein the mass of material A obtained after the solid-liquid separation described in step (1) is 3 to 3.7 times the mass of the carbon powder.

5. The temperature of the preliminary carbonization described in step (1) is 500 to 1200°C, and the time is 1 to 6 hours; The preliminary carbonization in step (1) is carried out under a protective gas, and the protective gas comprises any one or a combination of at least two of nitrogen gas, argon gas, krypton gas, and helium gas; The particle size D50 of the carbon powder described in step (1) is 5 to 45 μm, The solid-liquid separation method according to step (1) includes press filtration; The method according to claim 3 or 4, wherein drying is further performed after the solid-liquid separation described in step (1), and the drying temperature is 150 to 300 ° C. and the drying time is 2 to 4 h.

6. The catalyst according to step (1) comprises an inorganic salt and / or an organic salt, and is an inorganic salt and / or an organic salt of any one or a combination of at least two of vanadium, chromium, manganese, iron, cobalt, nickel, or copper; The carbon source according to step (1) comprises a biomass carbon source and / or a biomass secondary processed material; The biomass carbon source comprises any one or a combination of at least two of straw, fruit kernel, wood, or bamboo; The manufacturing method according to any one of claims 3 to 5, wherein the biomass secondary processed material comprises any one or a combination of at least two of glucose, sucrose, starch, lignin, cellulose, or hemicellulose.

7. Prior to the heat treatment in step (2), the composite particles are further subjected to an isostatic treatment; The pressure increase rate of the isostatic pressure treatment is 5 to 100 MPa / min, and the pressure is 200 to 400 MPa; The pressure retention time of the isostatic pressure treatment is 10 to 120 min, and the pressure reduction rate is 5 to 100 MPa / min, The number of times of the isostatic pressure treatment is two or more, The method according to any one of claims 3 to 6, wherein the temperature of the heat treatment in step (2) is 1300 to 1900°C and the time is 1 to 5 hours.

8. the post-treatment in step (2) comprises pickling, water washing and drying, which are carried out in sequence; the pickling solution used in the pickling contains hydrochloric acid and / or hydrofluoric acid, The method according to any one of claims 3 to 7, wherein the drying temperature is 150 to 300°C and the drying time is 0.5 to 3 hours.

9. The manufacturing method includes: Step (1): pre-carbonizing a carbon source under a protective gas at a temperature of 500-1200°C for 1-6 hours to obtain carbon powder having a particle size D50 of 5-45 μm; then immersing the carbon powder in a catalyst solution under vacuum for 1-2.5 hours, and then press-filtering the filtered cake; drying the filtered cake at 150-300°C for 2-4 hours to obtain composite particles carrying a catalyst, wherein the mass ratio of the carbon powder to the catalyst solution is 1:(4-7); 9. The method according to claim 3, further comprising: (2) increasing the pressure of the composite particles according to step (1) to 200-400 MPa at a pressure increase rate of 5-100 MPa / min, subjecting the composite particles to isostatic pressure treatment for 10-120 minutes, and releasing the pressure at a pressure decrease rate of 5-100 MPa / min to obtain an isostatically pressurized material; and (3) heat-treating the isostatically pressurized material at a temperature of 1300-1900°C for 1-5 hours, and then sequentially pickling, washing with water, and drying to obtain the catalytic graphite material.

10. A lithium ion battery comprising the catalytic graphite material of claim 1 or 2.

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