A coated carbon-based composite material, and a method of making and use thereof

Abstract

The application provides a coated carbon-based composite material and a preparation method and application thereof, and comprises the following steps: S1, pyrolysis carbonization of a hard carbon precursor, crushing, and sieving to obtain primary particles; S2, mixing the primary particles obtained in S1 with a conductive agent and performing coating modification, carbonization, and sieving to obtain a coated carbon-based composite material. The obtained material has high conductivity, excellent rate performance and first discharge efficiency as a sodium battery negative electrode material, and the material preparation method is simple and easy to scale up.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of sodium ion battery negative electrode materials, and particularly relates to a coated carbon-based composite material and a preparation method and application thereof. BACKGROUND

[0002] High-performance secondary batteries are the most efficient and most convenient energy storage and conversion devices, which are crucial for establishing a clean energy system and realizing large-scale energy storage. Secondary batteries represented by lithium ion batteries have become the most promising energy storage technology due to their high energy density, high energy conversion efficiency, long cycle life and other advantages. However, with the continuous growth of electric vehicles and consumer electronics, the scarcity and uneven spatial distribution of lithium resources limit the application of lithium ion batteries in large-scale energy storage. Sodium ion batteries are considered to be a beneficial supplement to lithium ion batteries due to their abundant resources, wide distribution and low cost, and are one of the ideal devices for large-scale energy storage. The research and development of sodium ion battery technology have important strategic significance, and have attracted widespread attention from research groups around the world in recent years.

[0003] CN110752368B discloses a preparation method and application of a sodium ion battery negative electrode material, which directly uses a two-step carbonization method to prepare a carbon material, but the conductivity and initial discharge efficiency of the material are poor; CN109742383B obtains a resin-based hard carbon material through hydrothermal and carbonization methods, which exhibits good charge and discharge capacity as a sodium ion battery negative electrode material, but the hydrothermal method is difficult to scale up for mass production; CN115084531B and CN107507964A disclose a coating method of carbon material, but the coating method is single and does not involve a conductive agent, resulting in low conductivity and poor performance of the material. SUMMARY

[0004] In view of the problems in the prior art, the application provides a coated carbon-based composite material and a preparation method and application thereof. The obtained material has high conductivity, excellent rate performance and initial discharge efficiency as a sodium battery negative electrode material, and the material preparation method is simple and easy to scale up.

[0005] The application is achieved by the following technical solutions:

[0006] A preparation method of a coated carbon-based composite material, comprising the following steps: S1, pyrolytic carbonization of a hard carbon precursor, crushing, and sieving to obtain primary particles; S2, mixing the primary particles obtained in S1 with a conductive agent and performing coating modification, carbonization, and sieving to obtain a coated carbon-based composite material.

[0007] Preferably, in S1, the hard carbon precursor is biomass and / or a high molecular compound; the biomass is one or a combination of at least two of glucose, sucrose, starch, cellulose, lignin, wood chips, bamboo chips, coconut shells and nut shells; the high molecular compound is one or a combination of at least two of epoxy resin, phenolic resin, furfural resin and urea-formaldehyde resin.

[0008] Preferably, in S1, the pyrolysis carbonization is performed in an inert atmosphere at a temperature of 400-1000℃ for 1-10h.

[0009] Preferably, in S2, the coating modification adopts any one of gas phase coating, liquid phase coating or solid phase coating.

[0010] Further, the step of the gas phase coating is: mixing the primary particles obtained in S1 with a conductive agent and a binder into a solvent to obtain a mixed slurry, drying, primary carbonization to obtain secondary particles; transferring the secondary particles to a gas phase deposition furnace, heating to a coating temperature in an inert atmosphere, introducing a coating gas source to perform gas phase coating; the primary carbonization is performed in an inert atmosphere at a temperature of 400-1000℃ for 1-10h; the coating temperature is 700-900℃, and the coating time is 1-4h; the coating gas source is any one or a combination of at least two of methane, ethane, acetylene, propylene, acetone, benzene, toluene and xylene.

[0011] Further, the step of the liquid phase coating is: mixing the primary particles obtained in S1 with a conductive agent and a binder into a solvent to obtain a mixed slurry, spray granulating the mixed slurry under the protection of an inert atmosphere, and performing primary carbonization; the primary carbonization is performed in an inert atmosphere at a temperature of 400-1000℃ for 1-10h.

[0012] Further, the step of the solid phase coating is: fusing the primary particles obtained in S1 with a conductive agent and a solid phase coating carbon source, crushing, and sieving; the solid phase coating carbon source is any one or a combination of at least two of pitch, sugar, organic acid and high molecular compound.

[0013] Preferably, in S2, the carbonization is performed in an inert atmosphere at a temperature of 700-1500℃ for 1-10h.

[0014] The coating type carbon-based composite material obtained by the preparation method.

[0015] The coating type carbon-based composite material as a negative electrode material in a secondary battery.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] The biomass or high polymer resin hard carbon precursor is carbonized to obtain a closed microporous carbon structure with a large amount of sodium storage platform capacity; by adding a conductive agent and surface coating modification, the conductivity, morphology and specific surface area of the material are improved, and the reversible specific capacity and initial discharge efficiency of the material as a sodium battery negative electrode material are improved. The prepared coated carbon-based composite material has outstanding performance, can replace the existing sodium ion battery carbon-based negative electrode material, and is simple to prepare and easy to popularize in the field of sodium ion batteries.

[0018] The biomass or high polymer compound is used as a hard carbon precursor, and the prepared material has higher sodium battery specific capacity, and the raw material is easy to obtain. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The Raman spectrum of the coated carbon-based composite material prepared by taking biomass as a carbon source in Example 1.

[0020] Figure 2 The X-ray diffraction spectrum of the coated carbon-based composite material prepared by taking biomass as a carbon source in Example 1. DETAILED DESCRIPTION

[0021] In order to further understand the present application, the present application will be described below in conjunction with examples, which are only further explanations of the features and advantages of the present application, and are not used to limit the claims of the present application.

[0022] The hard carbon precursor is carbonized, crushed, and sieved, and then mixed with a conductive agent and a binder for secondary carbonization, and finally coated and modified and carbonized to form a high-conductivity coated carbon-based composite material, which can be used as a sodium ion battery negative electrode material.

[0023] The present application is a preparation method of a coated carbon-based composite material, comprising the following steps:

[0024] Step 1, pyrolysis carbonization of the hard carbon precursor in an inert atmosphere, crushing, and sieving to obtain primary particles;

[0025] Step 2, mixing the primary particles obtained in step 1 with a conductive agent and a binder into a solvent to obtain a mixed slurry, drying, and carbonizing to obtain secondary particles;

[0026] Step 3, coating modification, carbonization, crushing, and sieving of the secondary particles obtained in step 2 to obtain a coated carbon-based composite material.

[0027] In step 1, the hard carbon precursor is biomass and / or a high molecular compound; the biomass is one or a combination of at least two of glucose, sucrose, starch, cellulose, lignin, wood chips, bamboo chips, coconut shells, and nut shells; the high molecular compound is one or a combination of at least two of epoxy resin, phenolic resin, furfural resin, and urea-formaldehyde resin. The pyrolysis carbonization process is carried out in an inert atmosphere, at a temperature of 400-1000°C, further preferably 600-800°C; the pyrolysis carbonization time is 1-10h, further preferably 2-4h; the inert atmosphere is any one or a combination of at least two of nitrogen, argon, helium, and neon.

[0028] In step 2, the conductive agent is any one or a combination of at least two of carbon black, Ketjen black, acetylene black, Super-P, carbon nanotubes, carbon nanofibers, and graphene; the binder is any one or a combination of at least two of pitch, furfural resin, phenolic resin, epoxy resin, polyvinyl alcohol, and polyacrylonitrile; the solvent is any one or a combination of at least two of an alcohol solvent, a ketone solvent, and an ether solvent. The carbonization process is carried out in an inert atmosphere, at a temperature of 400-1000°C, further preferably 600-800°C; the carbonization time is 1-10h, further preferably 2-4h; the inert atmosphere is any one or a combination of at least two of nitrogen, argon, helium, and neon.

[0029] In step 3, the carbonization process is carried out in an inert atmosphere, at a temperature of 700-1500°C; the carbonization time is 1-10h; the inert atmosphere is any one or a combination of at least two of nitrogen, argon, helium, and neon. In step 3, the coating modification uses any one of gas-phase coating, liquid-phase coating, or solid-phase coating.

[0030] The step of gas-phase coating modification is: transferring the secondary particles obtained in step 2 to a gas-phase deposition furnace, heating to a coating temperature under an inert atmosphere, introducing a coating gas source, and maintaining at the coating temperature for a period of time; the inert atmosphere is any one or a combination of at least two of nitrogen, argon, helium, and neon; the coating temperature is 700-900°C; the coating gas source is any one or a combination of at least two of methane, ethane, acetylene, propylene, acetone, benzene, toluene, and xylene; the coating time is 1-4h.

[0031] When the coating modification method adopts liquid phase coating, the drying and carbonization steps in step 2 are not performed, and the step of the liquid phase coating modification is that the mixed slurry in step 2 is subjected to spray granulation under the protection of an inert atmosphere; the inert atmosphere is any one or a combination of at least two of nitrogen, argon, helium and neon; the rotation speed of the spray granulation equipment is 5000-25000 r / min; the temperature of the feeding port of the spray granulation equipment is 25-400 DEG C, and is further preferably 100-300 DEG C; the temperature of the discharging port of the spray granulation equipment is 15-150 DEG C, and is further preferably 60-100 DEG C; the solid content of the slurry for spray granulation is 10-80%, wherein the mass ratio of primary particles is 20-75%, the mass ratio of conductive agent is 0-5%, and the mass ratio of binder is 5-60%.

[0032] When the coating modification method adopts solid phase coating, the mixing, drying and carbonization steps in step 2 are not performed, and the step of the solid phase coating modification is that the primary particles obtained in step 1 are directly transferred into a mixing machine with conductive agent and solid phase coating carbon source to mix the materials uniformly; the solid phase coating carbon source is any one or a combination of at least two of pitch, sugar, organic acid and high molecular compound, and is further preferably any one or a combination of at least two of phenolic resin, furfural resin, epoxy resin, acrylic resin, polyvinyl alcohol and polyacrylonitrile; in the solid phase coating modification, the mixing machine includes any one of mechanical fusion machine, VC mixer, horizontal mixer and screw belt mixer; in the solid phase coating modification, the rotation speed of the mixing machine is 50-5000 r / min; and the mixing time is 1-200 min.

[0033] The application is further illustrated by the following examples.

[0034] Example 1

[0035] A preparation method of a coated carbon-based composite material, the method comprising the following steps:

[0036] The starch is carbonized at 600 DEG C for 3h under the protection of nitrogen in a sintering furnace, and then is broken, ball milled and sieved by a 325 mesh screen to obtain hard carbon primary particles;

[0037] The primary particles, Ketjen black and pitch are added into a certain amount of tetrahydrofuran according to the ratio of 85:1:14 to obtain a mixed slurry with a solid content of 10wt%, which is directly heated and dried, and then is carbonized at 700 DEG C for 3h under the protection of nitrogen in a sintering furnace, and then is broken, ball milled and sieved by a 325 mesh screen to obtain secondary particles;

[0038] The secondary particles are put into a CVD furnace, heated to 850℃ under nitrogen protection, acetylene gas is introduced into the furnace, coated for 2h, transferred to a rotary furnace, carbonized at 1300℃ under argon protection for 3h, sieved using a 325 mesh screen, to obtain a coated carbon-based composite material.

[0039] Example 2

[0040] A method for preparing a coated carbon-based composite material, the method comprising the following steps:

[0041] The starch is carbonized at 600℃ for 3h under nitrogen protection in a sintering furnace, then crushed, ball milled, and sieved using a 325 mesh screen to obtain hard carbon primary particles;

[0042] The primary particles, ketjen black, and pitch are added to a certain amount of tetrahydrofuran in a ratio of 85:1:14, mixed to obtain a mixed slurry with a solid content of 10wt%, spray granulated, the spray conditions are an inlet temperature of 350℃ and an outlet temperature of 110℃, carbonized at 600℃ for 3h under nitrogen protection, to obtain secondary particles;

[0043] The secondary particles are carbonized at 1400℃ for 2h under nitrogen protection, sieved using a 325 mesh screen, to obtain a coated carbon-based composite material.

[0044] Example 3

[0045] A method for preparing a coated carbon-based composite material, the method comprising the following steps:

[0046] The starch is carbonized at 600℃ for 3h under nitrogen protection in a sintering furnace, then crushed, ball milled, and sieved using a 325 mesh screen to obtain hard carbon primary particles;

[0047] The primary particles, ketjen black, and pitch are added to a certain amount of tetrahydrofuran in a ratio of 85:1:14, mixed to obtain a mixed slurry with a solid content of 10wt%, spray granulated, the spray conditions are an inlet temperature of 350℃ and an outlet temperature of 110℃, carbonized at 600℃ for 3h under nitrogen protection, to obtain secondary particles;

[0048] The secondary particles are carbonized at 1400℃ for 2h under nitrogen protection, sieved using a 325 mesh screen, to obtain a coated carbon-based composite material.

[0049] Example 4

[0050] A method for preparing a coated carbon-based composite material, the method comprising the following steps:

[0051] The wood chips are carbonized at 700℃ for 2h under nitrogen protection in a sintering furnace, then crushed, ball milled, and sieved using a 325 mesh screen to obtain hard carbon primary particles;

[0052] The primary particles are added to a certain amount of tetrahydrofuran in a proportion of 85:1:14 with acetylene black and pitch, mixed to obtain a mixed slurry with a solid content of 10wt%, directly heated and evaporated dry, heated to 700℃ in a sintering furnace under nitrogen protection for carbonization for 3h, then broken, ball milled, and sieved with a 325 mesh sieve to obtain secondary particles;

[0053] The secondary particles are put into a CVD furnace, heated to 870℃ under nitrogen protection, acetylene gas is introduced into the furnace, coated for 2h, transferred to a rotary furnace, carbonized at 1300℃ under argon protection for 3h, and sieved with a 325 mesh sieve to obtain a coated carbon-based composite material.

[0054] Example 5

[0055] A method for preparing a coated carbon-based composite material, the method comprising the following steps:

[0056] The cellulose is heated to 600℃ in a sintering furnace under nitrogen protection for carbonization for 3h, then broken, ball milled, and sieved with a 325 mesh sieve to obtain hard carbon primary particles;

[0057] The primary particles are added to a certain amount of tetrahydrofuran in a proportion of 85:1:14 with carbon nanotubes and epoxy resin, mixed to obtain a mixed slurry with a solid content of 10wt%, spray granulated, the spray conditions are an inlet temperature of 360℃ and an outlet temperature of 115℃, carbonized at 600℃ under nitrogen protection for 3h to obtain secondary particles;

[0058] The secondary particles are carbonized at 1400℃ under nitrogen protection for 2h, and sieved with a 325 mesh sieve to obtain a coated carbon-based composite material.

[0059] Example 6

[0060] A method for preparing a coated carbon-based composite material, the method comprising the following steps:

[0061] The coconut shell is heated to 600℃ in a sintering furnace under nitrogen protection for carbonization for 3h, then broken, ball milled, and sieved with a 325 mesh sieve to obtain hard carbon primary particles;

[0062] The primary particles are added to a mechanical fusion machine in a proportion of 84:2:14 with ketchen black and phenolic resin, the rotational speed is 800r / min, the cutter gap width is 0.1cm, and the fusion time is 2h, then broken, and sieved with a 325 mesh sieve to obtain secondary particles;

[0063] The secondary particles are carbonized at 1400℃ under argon protection for 2h, and sieved with a 325 mesh sieve to obtain a coated carbon-based composite material.

[0064] Example 7

[0065] A preparation method of a coated carbon-based composite material, the method comprising the following steps:

[0066] The sucrose is carbonized in a sintering furnace under nitrogen protection at 500 DEG C for 3h, then broken, ball milled, and sieved with a 325 mesh screen to obtain primary particles of hard carbon;

[0067] The primary particles, graphene, and pitch are added to a certain amount of tetrahydrofuran in a ratio of 85:1:14, mixed to obtain a mixed slurry with a solid content of 10wt%, and directly heated and evaporated dry, then carbonized in a sintering furnace under nitrogen protection at 700 DEG C for 3h, then broken, ball milled, and sieved with a 325 mesh screen to obtain secondary particles;

[0068] The secondary particles are put into a CVD furnace, heated to 900 DEG C under nitrogen protection, and methane gas is introduced into the furnace for 2h, then transferred to a rotary furnace and carbonized at 1300 DEG C under argon protection for 3h, and sieved with a 325 mesh screen to obtain a coated carbon-based composite material.

[0069] Example 8

[0070] A preparation method of a coated carbon-based composite material, the method comprising the following steps:

[0071] The nut shell is carbonized in a sintering furnace under nitrogen protection at 700 DEG C for 3h, then broken, ball milled, and sieved with a 325 mesh screen to obtain primary particles of hard carbon;

[0072] The primary particles, acetylene black, and phenolic resin are added to a certain amount of tetrahydrofuran in a ratio of 86:2:12, mixed to obtain a mixed slurry with a solid content of 15wt%, spray granulated, and spray granulation conditions are an inlet temperature of 350 DEG C, an outlet temperature of 110 DEG C, and carbonization at 700 DEG C under nitrogen protection for 3h to obtain secondary particles;

[0073] The secondary particles are carbonized at 1500 DEG C under nitrogen protection for 2h, and sieved with a 325 mesh screen to obtain a coated carbon-based composite material.

[0074] Example 9

[0075] A preparation method of a coated carbon-based composite material, the method comprising the following steps:

[0076] The wood chips are carbonized in a sintering furnace under nitrogen protection at 600 DEG C for 3h, then broken, ball milled, and sieved with a 325 mesh screen to obtain primary particles of hard carbon;

[0077] The primary particles are added to a mechanical fusion machine with Super-P and phenolic resin in a ratio of 84:2:14, the rotating speed is 2000r / min, the cutter gap width is 0.1cm, and the fusion time is 1h, then the primary particles are broken and sieved with a 325 mesh screen to obtain secondary particles;

[0078] The secondary particles are carbonized at 1500℃ for 1.5h under argon protection, and sieved with a 325 mesh screen to obtain the coated carbon-based composite material.

[0079] Comparative Example 1

[0080] A method for preparing a coated carbon-based composite material, the method comprising the following steps:

[0081] The starch is carbonized at 600℃ for 3h under nitrogen protection in a sintering furnace, then broken and ball milled, and sieved with a 325 mesh screen to obtain the hard carbon primary particles;

[0082] The primary particles are added to a certain amount of tetrahydrofuran with pitch in a ratio of 85:14, mixed to obtain a mixed slurry with a solid content of 10wt%, directly heated and evaporated dry, carbonized at 700℃ for 3h under nitrogen protection in a sintering furnace, then broken and ball milled, and sieved with a 325 mesh screen to obtain secondary particles;

[0083] The secondary particles are transferred into a CVD furnace, heated to 850℃ under nitrogen protection, acetylene gas is introduced into the furnace, coated for 2h, transferred into a rotary furnace, carbonized at 1300℃ for 3h under argon protection, and sieved with a 325 mesh screen to obtain the coated carbon-based composite material.

[0084] Comparative Example 1 is compared with Example 1, no conductive agent is added, and other conditions are the same.

[0085] Comparative Example 2

[0086] A method for preparing a carbon-based composite material, the method comprising the following steps:

[0087] The cellulose is carbonized at 600℃ for 3h under nitrogen protection in a sintering furnace, then broken and ball milled, and sieved with a 325 mesh screen to obtain the hard carbon primary particles;

[0088] The primary particles are added to a certain amount of tetrahydrofuran with carbon nanotubes in a ratio of 85:1, mixed to obtain a mixed slurry with a solid content of 10wt%, spray granulated, spray conditions are an inlet temperature of 360℃ and an outlet temperature of 115℃, carbonized at 600℃ for 3h under nitrogen protection to obtain secondary particles;

[0089] The secondary particles are carbonized at 1400℃ for 2h under nitrogen protection, and sieved with a 325 mesh screen to obtain the carbon-based composite material.

[0090] The comparative example 2 is not coated compared with example 5, and other conditions are the same.

[0091] Figure 1 The Raman spectrum of the coated carbon-based composite material prepared by taking biomass as the carbon source in example 1 is shown in the figure. The D peak at 1360 cm -1 and the G peak at 1595 cm -1 can be clearly seen in the figure, which respectively correspond to the non-graphitization structure and the graphitization structure in the carbon material, and the D peak is obviously higher than the G peak, which is a typical characteristic of hard carbon material.

[0092] Figure 2 The X-ray diffraction spectrum of the coated carbon-based composite material prepared by taking biomass as the carbon source in example 1 is shown in the figure. The two relatively wide peaks at 22° and 44° in the figure respectively correspond to the (002) and (100) diffraction peaks of the carbon material, and the wide peak shape indicates that the graphitization degree of the material is low.

[0093] In order to more intuitively show the performance of the material prepared by the application, the preparation parameters and electrochemical performance of the negative electrode material prepared in the above part of the examples are listed in the following table.

[0094] Table 1 Preparation parameters and electrochemical performance of the negative electrode material prepared in part of the examples

[0095]

[0096] As can be seen from table 1, compared with the comparative example, the reversible specific capacity and the first coulombic efficiency are obviously improved due to the addition of the conductive agent in example 1. Compared with comparative example 2, the reversible specific capacity and the first coulombic efficiency are also obviously improved due to the coating in example 5. It is shown that the method of the negative electrode material of the application can improve the electrochemical performance of the negative electrode material.

Claims

1. A method for producing a coated carbon-based composite material, characterized by, The method comprises the following steps: S1, pyrolysis carbonization of hard carbon precursor, crushing, screening, to get the first particles; S2, mixing and coating modification of the first particles obtained in S1 with conductive agent, carbonization, screening, to get the coated carbon-based composite material; wherein the coating modification adopts any one of gas phase coating, liquid phase coating or solid phase coating; The step of the gas phase coating is: mixing the first particles obtained in S1 with conductive agent and binder into the solvent to get the mixed slurry, drying, primary carbonization to get the secondary particles; transferring the secondary particles to the gas phase deposition furnace, heating to the coating temperature under inert atmosphere, introducing the coating gas source, and carrying out the gas phase coating; the primary carbonization is carried out in inert atmosphere, the temperature is 400-1000℃, and the time is 1-10 h; the coating temperature is 700-900℃, and the coating time is 1-4 h; the coating gas source is any one or combination of at least two of methane, ethane, acetylene, propylene, acetone, benzene, toluene and xylene; The step of the liquid phase coating is: mixing the first particles obtained in S1 with conductive agent and binder into the solvent to get the mixed slurry, and carrying out the spray granulation of the mixed slurry under the protection of inert atmosphere; The step of the solid phase coating is: fusing, crushing and screening the first particles obtained in S1 with conductive agent and solid phase coating carbon source; the solid phase coating carbon source is any one or combination of at least two of pitch, sugar, organic acid and high molecular compound.

2. The method for producing a coated carbon-based composite material according to claim 1, characterized by, In S1, the hard carbon precursor is biomass and / or high molecular compound; the biomass is one or combination of at least two of glucose, sucrose, starch, cellulose, lignin, wood chips, bamboo chips, coconut shell and nut shell; the high molecular compound is one or combination of at least two of epoxy resin, phenol formaldehyde resin, furfural resin and urea formaldehyde resin.

3. The method for preparing a coated carbon-based composite material according to claim 1, characterized in that, In S1, the pyrolysis carbonization is carried out in inert atmosphere, the temperature is 400-1000℃, and the time is 1-10 h.

4. The method for preparing a coated carbon-based composite material according to claim 1, characterized by, In S2, the carbonization is carried out under inert atmosphere, the temperature is 700-1500℃, and the carbonization time is 1-10 h.

5. The coated carbon-based composite material obtained by the preparation method of any one of claims 1-4.

6. The application of the coated carbon-based composite material of claim 5 as negative electrode material in secondary battery.

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