CN113072055B

CN113072055B - Carbon material and preparation method and application thereof

Info

Publication number: CN113072055B
Application number: CN202010011551.3A
Authority: CN
Inventors: 潘广宏; 梁文斌; 梁朋; 陈全彬
Original assignee: China Energy Investment Corp Ltd; National Institute of Clean and Low Carbon Energy
Current assignee: China Energy Investment Corp Ltd; National Institute of Clean and Low Carbon Energy
Priority date: 2020-01-06
Filing date: 2020-01-06
Publication date: 2023-03-31
Anticipated expiration: 2040-01-06
Also published as: CN113072055A

Abstract

The invention relates to the field of lithium ion batteries, and discloses a carbon material, and a preparation method and application thereof, wherein the ratio H/W of the peak height H and the peak width W of the 002 peak of the carbon material to the interlayer spacing d of (002) crystal face ₀₀₂ C-axis direction crystallite size L _c And a crystallite size L in the a-axis direction _a The following conditions are satisfied: (1) H/W is more than or equal to 500 and less than or equal to 3000; (2) D is not more than 0.350nm ₀₀₂ ≤0.385nm，38≤(L _a +L _c )/d ² ≤48，850≤100×(L _a +L _c ) ² /(log(d ₀₀₂ )) ¹⁰ Less than or equal to 1500. The carbon material provided by the invention has higher capacity and first coulombic efficiency, and has lower production cost.

Description

Carbon material and preparation method and application thereof

Technical Field

The invention relates to the field of lithium ion batteries, in particular to a carbon material and a preparation method and application thereof.

Background

Amorphous carbon materials are commonly used for applications as mechanical component materials, battery electrode materials, or thermally conductive materials. When the amorphous carbon is used for a secondary battery, the amorphous carbon has the advantages of high ion diffusion rate, good compatibility with electrolyte, good power characteristic, good cycle performance, good heat transfer capacity and the like, so that the amorphous carbon has wide application prospects in the fields of electric vehicles, frequency modulation and peak regulation power grids and large-scale energy storage.

CN105720233A provides a method for preparing a carbon material for a negative electrode of a lithium ion battery, which comprises the following steps: polymerizing the coal liquefaction residues; stabilizing the polymerization product, and carbonizing the stabilized product. However, the battery capacity of the lithium ion battery provided by the lithium ion battery can not meet the requirements of the fields of electric vehicles, frequency modulation and peak shaving power grids, large-scale energy storage and the like.

CN105098186A discloses a pyrolytic amorphous carbon material, a preparation method and a use thereof. The pyrolytic amorphous carbon material is granular, and the average grain diameter of the granules is 1-100 mu m; d is a radical of ₀₀₂ Value of 0.35-0.44nm, lc value between 0.5-4nm, and La value between 3-5 nm. The preparation method comprises the following steps: adding a hard carbon precursor and a soft carbon precursor into a solvent, and fully mixing to obtain slurry; drying the slurry, and then crosslinking and curing the slurry for 0.5 to 5 hours in an inert atmosphere at the temperature of between 200 and 600 ℃; then the high temperature treatment is carried out for 0.5 to 10 hours in the inert atmosphere under the condition of 1000 to 1600 ℃; after cooling, the pyrolized amorphous carbon material is obtained. The material has wide application, and is particularly suitable to be used as a negative electrode material of a sodium ion secondary battery or a lithium ion secondary battery.

However, the amorphous carbon material provided by the amorphous carbon material has low capacity, and the battery capacity of the sodium ion secondary battery or the lithium ion secondary battery provided by the amorphous carbon material cannot meet the requirements of the fields of electric vehicles, frequency modulation and peak regulation power grids, large-scale energy storage and the like.

CN1148739A discloses an amorphous carbon material, an electrode thereof and a secondary battery having such a battery. The material d ₀₀₂ :0.345-0.365nm, the ratio P of the number of carbon atoms to the total number of carbon atoms in the layered structure _S 0.54-0.85, the ratio of total nitrogen atoms to total carbon atoms in the amorphous carbon is 0.005 to 1-0.055. The amorphous carbon is heat treated in a vacuum or inert atmosphere for at least 30 minutes to provide the desired crystal structure. The carbonaceous material may take the form of a carbon fiber material, and is preferably short fibers obtained by grinding long carbon fibers. The carbon fiber is used as the carbonaceous material to prepare the amorphous carbon material, so that the production cost of the amorphous carbon material is greatly increased.

Disclosure of Invention

The invention aims to solve the problems of high preparation cost and low capacity and first coulombic efficiency of a carbon material for a battery in the prior art, and provides a carbon material, and preparation and application thereof.

In order to achieve the above object, a first aspect of the present invention provides a carbon material, wherein a ratio H/W of a peak height H to a peak width W of a 002 peak of the carbon material, and an interlayer spacing d of (002) crystal planes ₀₀₂ C-axis direction crystallite size L _c And a crystallite size L in the a-axis direction _a The following conditions are satisfied:

(1)500≤H/W≤3000；

(2)0.350nm≤d ₀₀₂ ≤0.385nm，38≤(L _a +L _c )/d ² ≤48，850≤100×(L _a +L _c ) ² /(log(d ₀₀₂ )) ¹⁰ ≤1500。

preferably, the carbon material 002 peak has a ratio H/W of peak height H to peak width W and an interlayer spacing d of (002) crystal face ₀₀₂ C-axis direction crystallite size L _c And a crystallite size L in the a-axis direction _a The following conditions are satisfied: (1) 550 is less than or equal to H/W is less than or equal to 2600; (2) D is not more than 0.350nm ₀₀₂ ≤0.380nm，37≤(L _a +L _c )/d ² ≤47，900≤100×(L _a +L _c ) ² /(log(d ₀₀₂ )) ¹⁰ ≤1400。

In a second aspect, the present invention provides a method of making a carbon material according to the present invention, comprising the steps of:

(1) Mixing a carbon precursor with a stabilizer solution to obtain a carbon precursor mixture;

(2) Under an oxidizing atmosphere, extruding and granulating the carbon precursor mixture to obtain carbon precursor particles;

(3) And carbonizing the carbon precursor particles under the inert gas or vacuum condition to obtain the carbon material.

Preferably, in the step (1), the stabilizer solution is at least one selected from the group consisting of a stearate solution, an epoxy compound solution and a polyol solution.

More preferably, the stabilizer is selected from at least one of a sodium stearate solution, a butyl epoxystearate solution, and a pentaerythritol solution.

Preferably, the mass concentration of the stabilizer solution is 0.1 to 50%, preferably 0.5 to 20%.

Preferably, the carbon precursor is subjected to pulverization and/or ball milling.

Preferably, the carbon precursor is a mixture of pitch and coal.

Preferably, the carbon precursor is selected from at least one of mesophase pitch, coal pitch and petroleum pitch; the coal is selected from at least one of anthracite, bituminous coal and lignite.

More preferably, the weight ratio of bitumen to coal is (1-100): (100-1), preferably (1-10): 10-1), more preferably (1-3): (3-1).

Preferably, the bitumen has a softening point of from 70 to 400 ℃, preferably from 75 to 320 ℃.

Preferably, the weight ratio of the carbon precursor to the stabilizer solution is 100:1-50, preferably 100:1-30.

Preferably, in the step (2), the oxidizing atmosphere is air and/or oxygen.

Preferably, the extrusion temperature is 60 to 400 ℃, preferably 70 to 350 ℃. .

Preferably, in the step (3), the conditions of the carbonization treatment include: the carbonization temperature is 1000-1800 ℃, preferably 1000-1700 ℃, and the carbonization time is 1-24h, preferably 2-20h.

Preferably, the carbon precursor is pre-carbonized before or after the stabilizer solution is added to the carbon precursor.

Preferably, the conditions of the pre-carbonization treatment include: 300-800 ℃, preferably 400-700 ℃, and the pre-carbonization time is 1-10h, preferably 2-6h.

In a third aspect, the invention provides a carbon material produced by the method of the invention.

In a fourth aspect, the invention provides a use of the carbon material of the invention in a battery anode.

Preferably, the battery is a lithium ion battery and/or a sodium ion battery.

By the technical scheme, the carbon material, the preparation method and the application thereof provided by the invention have the following beneficial effects:

(1) The battery using the amorphous carbon material as the cathode has higher capacity and first coulombic efficiency, and particularly, the capacity of the battery can reach 0.1C 300mAh/g, and the first coulombic efficiency can reach 86.8%

(2) The raw materials for preparing the carbon material are low in price, the preparation process is simple, and the cost is obviously reduced.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For numerical ranges, each range between its endpoints and individual point values, and each individual point value can be combined with each other to give one or more new numerical ranges, and such numerical ranges should be construed as specifically disclosed herein.

The first aspect of the present invention provides a carbon material wherein the ratio H/W of the peak height H to the peak width W of the 002 peak in the carbon material, and the interlayer spacing d of the (002) crystal plane ₀₀₂ C-axis direction crystallite size L _c And a crystallite size L in the a-axis direction _a The following conditions are satisfied:

(1)500≤H/W≤3000；

in the present invention, the carbon material has a peak height H and a slit width W of the 002 peak and an interlayer distance d of the (002) crystal face ₀₀₂ C-axis direction crystallite size L _c Measured by X-ray diffraction (XRD); crystallite dimension L in a-axis direction _a Measured by raman spectroscopy.

In the present invention, the carbon material having the characteristics of the present invention is suitably used in the fields of machine part materials, battery electrode materials, electrically conductive materials or thermally conductive materials, and the like

Further, when the ratio H/W of the peak height H to the peak width W of the 002 peak of the carbon material is H/W, the interlayer spacing d of the (002) crystal face ₀₀₂ C-axis direction crystallite size L _c And a crystallite size L in the a-axis direction _a The following conditions are satisfied: (1) 550 is less than or equal to H/W is less than or equal to 2600; (2) D is not more than 0.350nm ₀₀₂ ≤0.380nm，37≤(L _a +L _c )/d ² ≤47，900≤100×(L _a +L _c ) ² /(log(d ₀₀₂ )) ¹⁰ When the carbon material is less than or equal to 1400 ℃, the battery using the carbon material as the negative electrode hasImproved capacity and first coulombic efficiency.

(2) Extruding and granulating the carbon precursor mixture in an oxidizing atmosphere to obtain carbon precursor particles;

According to the invention, the carbon precursor is mixed with the stabilizer solution, and the stabilizer can improve the thermal stability of the precursor, so that the extrusion process is easier to operate, the composite uniformity of the carbon precursor, especially the asphalt and the coal, is increased, and the prepared carbon material generates a synergistic effect in the carbonization process to form a special nano microcrystalline structure, so that the provided carbon material has excellent electrochemical performance.

According to the present invention, the stabilizer solution is selected from at least one of a stearate solution, an epoxy compound solution, and a polyol solution.

Preferably, the stabilizer is selected from at least one of a sodium stearate solution, a butyl epoxystearate solution, and a pentaerythritol solution.

In the present invention, the stabilizer solution is a liquid stabilizer or a solution of a solid stabilizer in a solvent.

The solvent may be a solvent that is conventional in the art, and specifically, the solvent is at least one selected from ethanol, methanol, xylene, and water.

According to the invention, the mass concentration of the stabilizer solution is 0.1 to 50%, preferably 0.5 to 20%.

According to the invention, the carbon precursor is a mixture of pitch and coal.

In the invention, the mixture of the asphalt and the coal is used as the carbon precursor, and the asphalt and the coal have wide sources and low price, so the cost for preparing the carbon material is greatly reduced. Meanwhile, the asphalt and the coal can generate a synergistic effect after being compounded, and the performance is better.

According to the present invention, the carbon precursor is selected from at least one of mesophase pitch, coal pitch and petroleum pitch; the coal is selected from at least one of anthracite, bituminous coal and lignite.

According to the invention, the weight ratio of the bitumen to the coal is (1-100): (100-1), preferably (1-10): 10-1), more preferably (1-3): (3-1).

In the invention, the inventor discovers that the carbon material prepared by mixing the asphalt and the coal by adopting the weight ratio defined by the invention and the method defined by the invention for the mixed carbon precursor has excellent capacity and efficiency, and the cost of the preparation process is lowest.

According to the invention, the bitumen has a softening point of 70 to 400 ℃, preferably 75 to 320 ℃.

According to the invention, the weight ratio of the carbon precursor to the stabilizer solution is 100:1-50, preferably 100:1-30.

In the present invention, the inventors have studied and found that when the weight ratio of the stabilizer solution to the carbon precursor satisfies the range defined in the present application, the influence of the stabilizer on the capacity of the carbon material is optimized, and when the weight ratio of the stabilizer solution to the carbon precursor is too small, the stabilizer solution cannot well wet the carbon material carbon precursor, the uniformity of the carbon precursor is reduced during extrusion, and when the weight ratio of the stabilizer solution to the carbon precursor is too large, extrusion cannot be performed.

According to the invention, in step (2), the oxidizing atmosphere is air and/or oxygen.

According to the invention, the extrusion temperature is 60 to 400 ℃ and preferably 70 to 350 ℃.

In the invention, the carbon precursor particles obtained by extrusion and granulation have granular morphology, and are preferably treated by crushing and/or ball milling, and the average particle size of the carbon precursor particles obtained by granulation is 5-50 μm, preferably 6-30 μm.

According to the invention, the conditions of the carbonization treatment include: the carbonization temperature is 1000-1800 ℃, preferably 1000-1700 ℃, and the carbonization time is 1-24h, preferably 2-20h.

According to the invention, the carbon precursor is pre-carbonized before or after the stabilizer solution is added with the carbon precursor.

In the invention, the pre-carbonization treatment is carried out under the condition of inert gas or vacuum.

According to the invention, the conditions of the pre-carbonization treatment comprise: the pre-carbonization temperature is 300-800 ℃, preferably 400-700 ℃, and the pre-carbonization time is 1-10h, preferably 2-6h.

According to the invention, the battery is a lithium ion battery and/or a sodium ion battery.

The present invention will be described in detail below by way of examples. In the following examples of the present invention, the following examples,

1) Powder XRD analysis

The test was carried out using a diffractometer model D8Advance from Bruker AXS GmbH, bruker AXS, germany, with a tube voltage of 40kV, a tube current of 40mA, and a source of X-ray radiation of Cu Ka

The acquisition step is 0.02 DEG, and the acquisition 2 theta range is 10-60 deg. Calculating L according to Scherrer formula _c ，L _c ＝Kλ/B ₀₀₂ cos theta, wherein K is the Scherrer constant, lambda is the X-ray wavelength, B is the half-height width of the diffraction peak, and theta is the diffraction angle.

2) Raman spectroscopy

The test is carried out by adopting LabRAM HR-800 type Raman spectrometer of Horiba jobyvon of France, the laser wavelength is 532.06nm, the slit width is 100 μm, and the scanning range is 700-2100cm ^-1 . I from Raman Spectroscopy _G And I _D Value according to the formula L _a ＝4.4×I _G /I _D To calculate L _a 。

3) Particle size (D) ₅₀ )

The tests were carried out using a Malvern Mastersizer2000 laser particle sizer from Malvern instruments Ltd, UK.

6) Capacity of battery

The battery capacity was tested using a battery test system CT2001A battery tester from blue electronic gmbh, wuhan. A first charge-discharge capacity test was performed on a button cell including a negative electrode made of a carbon material (as a negative electrode material) of the following example and comparative example, respectively, in which the cell was charged at a constant current of 0.1C (1c = 370mah/g) to 3.0V and then discharged at a constant current of 0.1C to 0V, and the cell was measured and averaged to be a measured value.

7) First coulombic efficiency

First coulombic efficiency = first charge capacity/first discharge capacity.

The carbon content of the mesophase pitch I is 98 weight percent, the mesophase content is 80 weight percent, and the softening point is 320 ℃;

the carbon content of the mesophase pitch II is 97 wt%, the mesophase content is 70 wt%, and the softening point is 280 ℃;

the coal tar pitch has a carbon content of 93 wt% and a softening point of 160 ℃;

the petroleum asphalt has a carbon content of 90 wt% and a softening point of 100 ℃.

Anthracite, 9% by weight of volatile matter, 88% by weight of fixed carbon;

bituminous coal, 30 wt% volatiles, 65 wt% fixed carbon content;

all other raw materials are commercially available products.

Example 1

Mixing the mesophase pitch I and the anthracite coal according to the proportion of 1. Extrusion, granulation and ball milling at 330 ℃ under an air atmosphere were carried out to obtain a powder with D50=8 μm. The sample was carbonized at 1500 ℃ for 8 hours under vacuum to obtain carbon material A1.

Example 2

Mixing coal pitch and anthracite according to the proportion of 2: 1. extrusion, granulation and ball milling at 180 ℃ under air atmosphere, and then ball milling by a ball mill, resulted in a powder with D50=8 μm. Then carbonizing the mixture for 6 hours at 1600 ℃ under the vacuum condition to prepare a carbon material A2.

Example 3

Mixing petroleum asphalt and anthracite according to the proportion of 1: 1. the resulting mixture was extruded at 120 ℃ in an air atmosphere, granulated, and ball-milled by a ball mill to obtain a powder with D50=8 μm, and the sample was carbonized at 1400 ℃ for 12 hours under vacuum conditions to obtain a carbon material A3.

Example 4

Mixing the mesophase pitch II and the bituminous coal according to the proportion of 1, crushing by a small-sized crusher, and adding a stabilizer sodium stearate ethanol solution (mass concentration is 1 wt%), wherein the weight ratio of the carbon precursor to the sodium stearate ethanol solution is 20. Extrusion, granulation and ball milling at 300 ℃ under an air atmosphere gave a powder with D50=8 μm. The sample was carbonized at 1300 ℃ for 10 hours under vacuum to obtain carbon material A4.

Example 5

Mixing coal pitch and bituminous coal according to a ratio of 2 to 1, crushing the mixture by a small-sized crusher, adding a stabilizer sodium stearate ethanol solution (mass concentration is 1 wt%), wherein the weight ratio of the carbon precursor to the sodium stearate ethanol solution is 20, extruding and granulating the mixture at 170 ℃ in an air atmosphere, performing ball milling by a ball mill to obtain powder with D50=8 μm, and carbonizing the sample at 1400 ℃ for 6 hours under an inert gas to obtain a carbon material A5.

Example 6

Mixing petroleum asphalt and bituminous coal according to a ratio of 1. The sample was taken out and carbonized at 1300 ℃ for 10 hours under vacuum to obtain carbon material A6.

Example 7

A carbon material was prepared in the same manner as in example 2, except that: the weight ratio of the coal tar pitch to the anthracite is 1. Carbon material A7 was obtained.

Example 8

A carbon material was prepared in the same manner as in example 2, except that: the weight ratio of the coal tar pitch to the anthracite is 5. Carbon material A8 was obtained.

Example 9

A carbon material was prepared in the same manner as in example 1, except that: no sodium stearate in ethanol was added. Carbon material A9 was obtained.

Comparative example 1

A carbon material was prepared in the same manner as in example 1, except that: not extruded but carbonized directly. Carbon material D1 was obtained.

Comparative example 2

A carbon material was prepared in the same manner as in example 2, except that: and (3) replacing mesophase pitch II with phenolic resin to prepare a carbon material D2.

Comparative example 3

A carbon material was prepared in the same manner as in example 1, except that: anthracite was not used, only mesophase pitch I was used as the carbon precursor. Carbon material D3 was obtained.

Comparative example 4

A carbon material was prepared in the same manner as in example 1, except that: mesophase pitch I is not used, only anthracite is used as carbon precursor. Carbon material D4 was obtained.

TABLE 1 Performance parameters of carbon materials in examples 1-9 and comparative examples 1-4

As can be seen from the results in Table 1, the carbon materials A1 to A11 provided in examples 1 to 11 had a ratio H/W of the peak height H to the peak width W of the 002 peak and an interlayer spacing D of the (002) crystal plane, as compared with the carbon materials D1 to D4 provided in comparative examples 1 to 4 ₀₀₂ C-axis direction crystallite size L _c And a crystallite size L in the a-axis direction _a Satisfying the limitations of the present invention, the capacity and first coulombic efficiency of the battery using the carbon materials A1 to A9 as the negative electrode were tested to be significantly higher than those of D1 to D4.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including various technical features being combined in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A carbon material wherein the carbon material has a ratio H/W of a peak height H to a peak width W of a 002 peak and an interlayer spacing d of (002) crystal plane ₀₀₂ C-axis direction crystallite size L _c And a crystallite size L in the a-axis direction _a The following conditions are satisfied:

(1)500≤H/W≤3000；

(2)0.350nm≤d ₀₀₂ ≤0.385nm，38≤(L _a +L _c )/d ₀₀₂ ² ≤48，850≤(L _a +L _c ) ² /(lg(d ₀₀₂ )) ¹⁰ /100≤1500；

wherein the preparation method of the carbon material comprises the following steps:

(3) Carbonizing the carbon precursor particles under the inert gas or vacuum condition to obtain the carbon material;

wherein the carbon precursor is a mixture of pitch and coal;

the stabilizer solution is selected from at least one of a stearate solution, an epoxy compound solution and a polyalcohol solution.

2. The carbon material as claimed in claim 1, wherein the carbon material 002 has a ratio H/W of peak height H to peak width W of a peak, and an interlamellar spacing d of (002) crystal planes ₀₀₂ The crystallite size Lc in the c-axis direction and the crystallite size La in the a-axis direction satisfy the following conditions:

(1)550≤H/W≤2600；(2)0.350nm≤d ₀₀₂ ≤0.380nm，37≤(La+Lc)/d ₀₀₂ ² ≤47，900≤(La+Lc) ² /(lg(d ₀₀₂ )) ¹⁰ /100≤1400。

3. a method of preparing the carbon material of claim 1 or 2, comprising the steps of:

wherein the carbon precursor is a mixture of pitch and coal;

in the step (1), the stabilizer solution is at least one selected from a stearate solution, an epoxy compound solution and a polyol solution.

4. The method according to claim 3, wherein in step (1), the stabilizer is selected from at least one of a sodium stearate solution, a butyl epoxystearate solution, and a pentaerythritol solution.

5. The method according to claim 3, wherein in the step (1), the mass concentration of the stabilizer solution is 0.1-50%.

6. The method according to claim 5, wherein in the step (1), the mass concentration of the stabilizer solution is 0.5-20%.

7. The method of claim 3, wherein in step (1), the weight ratio of the carbon precursor to the stabilizer solution is 100:1-50.

8. The method of claim 7, wherein in step (1), the weight ratio of the carbon precursor to the stabilizer solution is 100:1-30.

9. The method of any one of claims 3-8, wherein the bitumen is selected from at least one of mesophase bitumen, coal bitumen, and petroleum bitumen; the coal is selected from at least one of anthracite, bituminous coal and lignite.

10. The method of any of claims 3-8, wherein the weight ratio of bitumen to coal is (1-100): (100-1).

11. The process of claim 10, wherein the weight ratio of bitumen to coal is (1-10): 10-1).

12. The method of claim 11 wherein the weight ratio of bitumen to coal is (1-3): (3-1).

13. The process according to any one of claims 3 to 8, wherein the bitumen has a softening point of from 70 to 400 ℃.

14. The process of claim 13, wherein the asphalt has a softening point of 75-320 ℃.

15. The method according to any one of claims 3 to 8, wherein the carbon precursor is subjected to pulverization and/or ball milling.

16. The method according to any one of claims 3 to 8, wherein in step (2), the oxidizing atmosphere is air and/or oxygen.

17. The process according to any one of claims 3 to 8, wherein in step (2) the extrusion temperature is in the range of from 60 to 400 ℃.

18. The process of claim 17, wherein in step (2), the extrusion temperature is from 70 to 350 ℃.

19. The method according to any one of claims 3 to 8, wherein in step (3), the conditions of the carbonization treatment include: the carbonization temperature is 1000-1800 ℃ and the carbonization time is 1-24h.

20. The method of claim 19, wherein in step (3), the conditions of the carbonization treatment comprise: the carbonization temperature is 1000-1700 ℃, and the carbonization time is 2-20h.

21. The method of any one of claims 3-8, wherein the carbon precursor is pre-carbonized before or after the addition of the carbon precursor to the stabilizer solution.

22. The method of claim 21, wherein the conditions of the pre-carbonization treatment comprise: the pre-carbonization temperature is 300-800 ℃, and the pre-carbonization time is 1-10h.

23. The method of claim 22, wherein the conditions of the pre-carbonization treatment comprise: the pre-carbonization temperature is 400-700 ℃, and the pre-carbonization time is 2-6h.

24. A carbon material produced by the method of any one of claims 3 to 23.

25. Use of the carbon material of any one of claims 1-2 or 24 in a battery negative electrode.

26. Use according to claim 25, wherein the battery is a lithium ion battery and/or a sodium ion battery.