CN116936800A

CN116936800A - Asphalt-based hard carbon negative electrode material and preparation method and application thereof

Info

Publication number: CN116936800A
Application number: CN202311125604.4A
Authority: CN
Inventors: 张劲斌; 顾凯; 朱周生; 钱佳丽; 王首亮
Original assignee: Ningbo Shanshan New Material Tech Co ltd
Current assignee: Ningbo Shanshan New Material Tech Co ltd
Priority date: 2023-09-01
Filing date: 2023-09-01
Publication date: 2023-10-24

Abstract

The invention discloses an asphalt-based hard carbon anode material, and a preparation method and application thereof. Which comprises the following steps: s1, carrying out an oxidative crosslinking reaction on a premix of coal tar pitch and an alkali metal reagent to obtain a first product; s2, mixing and kneading the first product with a binder, and performing compression molding to obtain a second product; s3, dehydrating and carbonizing the second product. In the invention, firstly, under the condition of the existence of alkali metal reagent, coal pitch is subjected to etching uniform oxidation crosslinking, and then under the existence of binder, kneading, compression molding, dehydration treatment and carbonization treatment are carried out, so that the solidification of a carbon material structure is realized, and the pitch-based hard carbon anode material is prepared. The pitch-based hard carbon negative electrode material has large graphite layer spacing of 0.38-0.42nm and high compaction density, not only can improve the uniform distribution of sodium in a carbon material, but also can improve the sodium storage capacity of the hard carbon material so as to improve the first discharge specific capacity and the first coulombic efficiency of a sodium ion battery.

Description

Asphalt-based hard carbon negative electrode material and preparation method and application thereof

Technical Field

The invention relates to the field of sodium ion battery material preparation, in particular to an asphalt-based hard carbon anode material, and a preparation method and application thereof.

Background

The sodium ion battery has the outstanding advantages of high energy density, long cycle life, safety, no pollution and the like as a green environment-friendly energy storage device, and has more application in new energy and energy storage as a supplement of lithium battery. With the rapid development of new energy automobiles, the demand of lithium ion batteries is rapidly increased, so that the lithium price is increased, and the development of new energy industries is greatly influenced. Under the background, sodium is attracting much attention due to the characteristics of large reserves, wide sources, low price, and similar working principles to lithium ion batteries.

The negative electrode as a key component of sodium electricity has an important influence on its performance. The negative electrode for a sodium ion battery generally includes a metal oxide, an organic material, a carbon material, and the like. The carbon materials in the materials become the first choice of the cathode materials due to the characteristics of low price, wide sources and good conductivity. Among them, hard carbon is most common among carbon-based anode materials. The hard carbon precursor mainly comprises biomass, resins, polymer precursors and the like, and the performances of different materials are greatly different: the stability of biomass material sources has a great influence on hard carbon performance; the resin has good performance when preparing hard carbon, but high cost, and the economy restricts the development of the hard carbon resin; while coal pitch performance is inferior to hard carbon performance of other materials, sources and economics are far superior to other precursor materials. Therefore, coal pitch has large-scale industrialization potential as a hard carbon precursor material.

Chinese patent document CN115259135 a discloses a method for preparing a hard carbon negative electrode material by a pitch-based oxidation method, which obtains pitch-based hard carbon by melting, air oxidation, pulverization, carbonization. Although the synthesis process is simple and convenient, has excellent process controllability and low production cost, and is easy to realize large-scale production, the oxidation efficiency of air or oxygen is low, meanwhile, the problem of uneven oxidation is easy to generate, and meanwhile, the problem of low initial efficiency when the synthesis process is used for sodium ion batteries cannot be solved.

Chinese patent document CN 115611264A discloses a pitch-based hard carbon negative electrode material, a preparation method and a sodium ion battery, wherein the preparation of sodium-electricity hard carbon is realized through two steps of pre-oxidation and high-temperature carbonization. Although the method has simple flow and is easy for industrial production, the oxidant adopted by the hard carbon prepared by the method can easily introduce impurities into the hard carbon, and meanwhile, the problem of low initial efficiency of the hard carbon applied to sodium ion batteries cannot be solved.

Chinese patent CN 109037603B discloses a novel method for preparing a pitch-based spherical porous doped modified hard carbon negative electrode material, which obtains a hard carbon material by cross-linking oxidation, spray granulation, carbonization, and coated graphitization. Although the hard carbon obtained by the method has good performance, the whole process is complex, and particularly, the problems of incomplete and uneven crosslinking and oxidization exist in the crosslinking and oxidization link due to the higher viscosity of asphalt.

Chinese patent document CN 115991467A discloses an oxidized asphalt-based hard carbon anode material for sodium ion batteries and a preparation method thereof, wherein asphalt is oxidized by adopting a fluidized bed, and the oxidation degree and uniformity are greatly improved compared with those of the traditional method, but the initial coulomb efficiency is still lower when the oxidized asphalt-based hard carbon anode material is used for sodium ion batteries.

The above problems are to be solved.

Disclosure of Invention

The invention aims to overcome the defect that the first discharge capacity or the first coulombic efficiency is low when the anode material prepared by taking coal pitch as a hard carbon precursor material in the prior art is applied to a sodium ion battery, and provides an asphalt-based hard carbon anode material, a preparation method and application thereof.

The invention solves the technical problems through the following technical proposal.

The invention provides a preparation method of an asphalt-based hard carbon anode material, which comprises the following steps:

s1, carrying out an oxidative crosslinking reaction on a premix of coal tar pitch and an alkali metal reagent to obtain a first product; wherein the mass of the alkali metal reagent is 2-40% of the mass of the coal tar pitch;

s2, mixing and kneading the first product with a binder, and performing compression molding to obtain a second product; the mass of the binder is 5% -40% of the mass of the first product;

s3, carrying out dehydration treatment and carbonization treatment on the second product to obtain the asphalt-based hard carbon anode material.

In S1, preferably, the coal pitch has a softening point of 150 ℃ to 280 ℃, for example 180 ℃.

In S1, preferably, the coal pitch has a coking value of 60% to 82%, for example 61%.

In S1, the particle size of the coal pitch is preferably 150 μm or less.

In S1, the alkali metal reagent may be an alkaline earth metal or an alkaline earth metal-containing compound, such as a hydroxide, carbonate or bicarbonate of Na metal, which is conventional in the chemical arts.

In a preferred embodiment, naOH is used as the alkali metal reagent.

In S1, preferably, the mass of the alkali metal reagent is 5% -38%, for example 5%, 10%, 15%, 20%, 25%, 30% or 35% of the mass of the coal tar pitch.

In S1, the pre-mixture is generally obtained by uniformly mixing the coal tar pitch and the alkali metal reagent.

In S1, the oxidative crosslinking reaction is generally carried out in a tube furnace.

In S1, the temperature of the oxidative crosslinking reaction is preferably 350 to 600 ℃, more preferably 400 to 550 ℃, for example 450 ℃.

In S1, the time of the oxidative crosslinking reaction is preferably 1 to 6 hours, more preferably 2 to 4 hours, for example 3 hours.

In the S1, in the oxidation crosslinking reaction process, on one hand, the effect of expanding the interlayer spacing of the carbon material is realized by utilizing the etching effect of an alkali metal reagent, and on the other hand, the uniform oxidization of coal tar pitch is realized while the etching of the alkali metal is carried out, so that the interlayer spacing of the graphite of the carbon material is expanded in situ, and the sodium storage capacity of the hard carbon material is improved; and simultaneously curing and forming the hard carbon precursor asphalt with a cross-linked structure by heat treatment. In S1, if coal tar pitch is pre-carbonized in advance and then is put into a tube furnace together with an alkali metal reagent, not only is the oxidation process deficient, but also the prepared carbon is soft carbon, and the alkali metal reagent only plays roles of etching, pore-forming and reaming, so that the capacity of the obtained product is greatly reduced.

In S1, after the oxidative crosslinking reaction, the resulting product is generally washed to neutrality and dried.

In S1, the sodium content of the first product is preferably 30ppm to 100ppm, for example 48ppm. Controlling the sodium content in the first product can avoid the excessive sodium content of the material caused by the subsequent addition of the sodium-containing binder, thereby further affecting the material performance.

In S1, the oxygen content of the first product is preferably 5.4% to 38.7%, for example 24.6%. Controlling the oxygen content in the first product can avoid the influence of the subsequent excessively high oxygen-containing functional groups on the post-reduction treatment process.

In S2, the binder is typically added in the form of a binder solution.

When the binder is added in the form of a binder solution, the concentration of the binder solution is preferably 0.1 to 1.5%, more preferably 0.2 to 1.3%, for example 0.8% or 1%.

When the binder is added in the form of a binder solution, the viscosity of the binder solution is preferably 400 to 5000 mPa-s (25 ℃), for example 2890 mPa-s.

In S2, the binder may be of a kind conventional in the art, preferably one or more of carboxymethyl cellulose, starch and sodium lignin sulfonate. Wherein the degree of substitution of the carboxymethyl cellulose is preferably 0.4 to 0.9, for example 0.6 to 0.8.

The pH of the carboxymethyl cellulose is preferably from 6 to 8, for example 7.8.

In S2, preferably, the mass of the binder is 5% -35% of the mass of the first product. For example, the binder mass is 5%, 15%, 25%, 35% or 40% of the first product mass.

In S2, the kneading is generally performed in a kneader conventional in the art.

In S2, the kneading time is preferably 10min-80min, more preferably 20min-60min, for example 20min, 25min, 30min, 40min, 45min or 50min.

In S2, the pressure of the compression molding is preferably 30MPa to 120MPa, more preferably 60MPa to 100MPa, for example 60MPa, 70MPa, 80MPa, 90MPa or 100MPa.

In S3, the dehydration treatment and the carbonization treatment are generally performed in a tube furnace.

In S3, the dehydration treatment and the carbonization treatment are preferably performed under an inert atmosphere and H ₂ And the mixture is carried out under the condition of mixed gas. Wherein the inert atmosphere and H ₂ In the mixed gas, H ₂ Preferably 2% -20%, e.g. 2%, 5%, 8%, 10%, 15% or 18%, by volume, the percentages being H ₂ The volume percentage of the mixed gas is calculated.

In S3, the rate of heating to the dehydration treatment temperature is preferably 0.5 ℃/min to 5 ℃/min, for example 2 ℃/min.

In S3, the dehydration time during the dehydration treatment is preferably 1 to 3 hours, for example 1 hour.

In S3, the dehydration temperature during the dehydration treatment is preferably 100 to 240 ℃, for example 200 ℃.

In S3, the rate of heating to the carbonization treatment temperature is preferably 5-10 ℃/min.

In S3, the carbonization time is preferably 1 to 5 hours, more preferably 2 to 4 hours, for example 3 hours, during the carbonization treatment.

In S3, the carbonization temperature is preferably 900-1290 ℃, more preferably 950-1250 ℃.

In S3, the dehydration treatment and the carbonization treatment preferably include the steps of: in inert atmosphere and H ₂ Under the mixed gas, the second product is subjected to heat preservation and dehydration treatment at 100-240 ℃, and then is directly heated to 900-1290 ℃ for carbonization treatment.

Wherein the inert atmosphere and H ₂ In the mixed gas, H ₂ Preferably 2% -20%, e.g. 2%, 5%, 8%, 10%, 15% or 18%, by volume, the percentages being H ₂ The volume percentage of the mixed gas is calculated.

In S3, the sodium content of the carbonized product is preferably regulated.

Wherein, the method for regulating and controlling the sodium content of the product can be conventional in the field, and is generally washing. The temperature of the washing is preferably 30-80 ℃, more preferably 40-60 ℃, for example 60 ℃. The washing time is preferably 1 to 24 hours, more preferably 3 to 18 hours, for example 6 hours.

In S3, the Na content of the pitch-based hard carbon anode material is preferably 60 to 300ppm, for example 180ppm.

In S3, the asphalt-based hard carbon anode material is also subjected to ball milling and screening.

The invention also provides the asphalt-based hard carbon anode material prepared by the preparation method.

In the invention, the D50 of the pitch-based hard carbon anode material can be 13+/-2 m ² /g。

In the invention, the compaction density of the asphalt-based hard carbon anode material can be 1.08-1.22g/cm ² 。

In the invention, the first discharge specific capacity of the asphalt-based hard carbon anode material can be 402-414mAh/g.

In the invention, the first coulomb efficiency of the asphalt-based hard carbon anode material can be 91.5% -94%.

In the invention, the graphite interlayer spacing of the pitch-based hard carbon anode material can be 0.38-0.42nm.

In the invention, the BET of the pitch-based hard carbon anode material can be 2.9-6.3m ² /g。

The invention also provides application of the asphalt-based hard carbon anode material in the field of sodium ion batteries.

On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.

The reagents and materials used in the present invention are commercially available.

The invention has the positive progress effects that:

in the invention, firstly, under the condition of the existence of alkali metal reagent, coal pitch is subjected to etching uniform oxidation crosslinking, and then under the existence of binder, kneading, compression molding, dehydration treatment and carbonization treatment are carried out, so that the solidification of a carbon material structure is realized, and the pitch-based hard carbon anode material is prepared. The pitch-based hard carbon negative electrode material has large graphite layer spacing of 0.38-0.42nm and high compaction density, not only can improve the uniform distribution of sodium in a carbon material, but also can improve the sodium storage capacity of the hard carbon material so as to improve the first discharge specific capacity and the first coulombic efficiency of a sodium ion battery.

Drawings

Fig. 1 is a charge-discharge curve of a sodium ion battery prepared from the hard carbon negative electrode material obtained in example 2.

Detailed Description

The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.

In the following examples, the raw materials were as follows:

coal pitch was purchased from Hebei Weixiang chemical technology Co., ltd, and had a softening point of 180℃and a coking value of 61%. The fused salt is NaOH and is purchased from Tianjin chemical reagent Co., ltd, and the purity is more than or equal to 98%. Carboxymethyl cellulose is purchased from Shandong Fanglite composite material Co., ltd, has a substitution degree of 0.6-0.8 and a pH value of 7.8.

Example 1

S1, crushing coal tar pitch to be less than 150 mu m, and uniformly mixing the coal tar pitch with molten salt to obtain a premix, wherein the adding proportion of the molten salt is 20% of the mass of the coal tar pitch;

under inert atmosphere, putting the raw materials into a tube furnace, heating to 450 ℃, and preserving heat for 3 hours to perform oxidation crosslinking reaction; after molten salt treatment, washing to neutrality and drying to obtain a first product (sodium content 48ppm, oxygen content 24.6%);

s2, preparing a carboxymethyl cellulose solution with the concentration of 1% (the viscosity is 2890 mPa.s), adding the first product and the carboxymethyl cellulose solution (the dosage of the carboxymethyl cellulose is 15 percent, and the percentages are the percentages of the mass of the binder and the mass of the first product) into a kneader, and kneading for 60 minutes. After the kneading treatment is finished, molding according to the pressure of 80MPa to obtain a second product;

s3, loading the second product into a tube furnace, heating to 200 ℃ at a heating rate of 2 ℃/min under the conditions of inert atmosphere and H2 mixed gas (80% of nitrogen and 20% of hydrogen), preserving heat for 1H, dehydrating, directly heating to 1250 ℃ at a heating rate of 10 ℃/min after dehydrating, preserving heat for 3H, and carbonizing;

and washing the obtained carbide at the washing temperature of 60 ℃ for 6 hours to obtain a third product, wherein the sodium content of the third product is 180ppm.

Examination of molten salt addition amount of examples (2-1) to (2-5)

Examples (2-1) -examples (2-5) differ from example 1 only in that the molten salt ratio in step S1 was adjusted to 5% -40%, and the rest of the preparation process was the same as that of example 1.

TABLE 1

Examples	Molten salt addition ratio
		Example 2-1	5％
Example 2-2	10％
		Examples 2 to 3	30％
Examples 2 to 4	40％

EXAMPLE (3-1) -EXAMPLE (3-4) examination of carboxymethyl cellulose concentration

Examples (3-1) -examples (3-4) differ from example 1 only in that the amount of carboxymethyl cellulose used in S2 was adjusted to 0.2% -1.3%, and the rest of the preparation process was the same as that of example 1.

TABLE 2

EXAMPLE (4-1) -EXAMPLE (4-3) examination of the amount of carboxymethylcellulose added

Examples (4-1) - (4-3) differ from example 1 only in that the ratio of carboxymethyl cellulose added in S2 was adjusted to 5% -40%, and the rest of the preparation process was the same as that of example 1.

Examples	Carboxymethyl cellulose addition ratio
		Example 4-1	5％
Example 4-2	25％
		Examples 4 to 3	40％

Examination of the molding pressure of examples (5-1) -example (5-4)

Examples (5-1) -example (5-4) were different from example 1 only in that the molding pressure in S2 was adjusted to 60-100MPa, and the remaining production processes were the same as in example 1.

TABLE 3 Table 3

Examples	Forming pressure MPa
		Example 5-1	60
Example 5-2	70
		Examples 5 to 3	90
Examples 5 to 4	100

Examination of kneading time of examples (6-1) -example (6-3)

Examples (6-1) -example (6-3) were different from example 1 only in that the kneading time in S2 was adjusted, and the rest of the preparation process was the same as in example 1.

TABLE 4 Table 4

Example (7-1) -example (7-3) examination of Hydrogen ratio

Example (7-1) -example (7-3) was different from example 1 only in that the volume ratio of hydrogen in the mixed gas in S3 was adjusted, and the remaining production processes were the same as in example 1.

TABLE 5

Examples	Hydrogen gas flow%
		Example 7-1	2
Example 7-2	5
		Examples 7 to 3	10

Example 8

S1: molten salt treatment: crushing coal tar pitch to less than 150 mu m, mixing the coal tar pitch with molten salt, wherein the adding proportion of the molten salt is 2% of the mass of the coal tar pitch, and after the mixing is finished. Under inert atmosphere, the raw materials are put into a tube furnace, heated to 400 ℃ and kept for 2 hours. Washing to neutrality and drying after molten salt treatment to obtain a first product;

s2: and (3) forming: preparing a carboxymethyl cellulose solution with a certain concentration, adding the first product and the carboxymethyl cellulose solution with the concentration of 1.3% into a kneader, and kneading for 30min. After the kneading treatment is finished, molding according to the pressure of 60MPa to obtain a second product;

s3: high-temperature carbonization treatment: and (3) loading the obtained second product into a tube furnace, heating to 150 ℃ at a heating rate of 0.5 ℃/min under the conditions of inert atmosphere and H2 mixed gas (nitrogen gas 90% and hydrogen gas 10%), preserving heat for 1H, directly heating to 950 ℃ at a heating rate of 10 ℃/min after the heat preservation is finished, and preserving heat for 5H until carbonization is finished, thus obtaining a third product.

S4: sodium content control treatment: and (3) washing the third product to control the sodium content in the final product, wherein the washing temperature is 40 ℃ and the washing time is 3 hours.

Example 9

S1: molten salt treatment: crushing coal tar pitch to less than 150 mu m, mixing the coal tar pitch with molten salt, wherein the adding proportion of the molten salt is 40% of the mass of the coal tar pitch, and after the mixing is finished. Under inert atmosphere, the raw materials are put into a tube furnace, heated to 550 ℃ and kept for 5 hours. Washing to neutrality and drying after molten salt treatment to obtain a first product;

s2: and (3) forming: preparing a carboxymethyl cellulose solution with a certain concentration, adding the first product and the 0.2% carboxymethyl cellulose solution into a kneader, and kneading for 70min. After the kneading treatment is finished, molding according to the pressure of 100MPa to obtain a second product;

s3: high-temperature carbonization treatment: and (3) loading the obtained second product into a tube furnace, heating to 220 ℃ at a heating rate of 5 ℃/min under the conditions of inert atmosphere and H2 mixed gas (95% of nitrogen and 5% of hydrogen), preserving heat for 2 hours, directly heating to 1000 ℃ at a heating rate of 10 ℃/min after the heat preservation is finished, and preserving heat for 3 hours until carbonization is finished, thus obtaining a third product.

S4: sodium content control treatment: and (3) washing the third product to control the sodium content in the final product, wherein the washing temperature is 60 ℃ and the washing time is 18 hours.

Comparative example 1

S1: molten salt treatment: crushing coal tar pitch to less than 150 mu m, mixing the coal tar pitch with molten salt, wherein the adding proportion of the molten salt is 40% of the mass of the coal tar pitch, and after the mixing is finished. Under inert atmosphere, the raw materials are put into a tube furnace, heated to 700 ℃ and kept for 8 hours. Washing to neutrality and drying after molten salt treatment to obtain a first product;

s2: and (3) forming: preparing a carboxymethyl cellulose solution with a certain concentration, adding the first product and the carboxymethyl cellulose solution with the concentration of 0.1% into a kneader, wherein the adding ratio is 15%, and the kneading time is 70min. After the kneading treatment is finished, forming according to the pressure of 120MPa to obtain a second product;

s3: high-temperature carbonization treatment: and (3) loading the obtained second product into a tube furnace, heating to 220 ℃ at a heating rate of 2 ℃/min under the conditions of inert atmosphere and H2 mixed gas (95% of nitrogen and 5% of hydrogen), preserving heat for 2 hours, directly heating to 1000 ℃ at a heating rate of 10 ℃/min after the heat preservation is finished, and preserving heat for 3 hours until carbonization is finished, thus obtaining a third product.

S4: sodium content control treatment: and (3) washing the third product to control the sodium content in the final product, wherein the washing temperature is 60 ℃ and the washing time is 0.5h.

Comparative example 2

S1: molten salt treatment: crushing coal pitch to less than 150 mu m, mixing the coal pitch with molten salt, wherein the adding proportion of the molten salt is 1% of the mass of the coal pitch, and after the mixing is finished. Under inert atmosphere, the raw materials are put into a tube furnace, heated to 300 ℃ and kept for 8 hours. Washing to neutrality and drying after molten salt treatment to obtain a first product;

s2: and (3) forming: preparing a carboxymethyl cellulose solution with a certain concentration, adding the first product and the carboxymethyl cellulose solution with the concentration of 1.4% into a kneader, wherein the adding proportion is 15%, and the kneading time is 10min. After the kneading treatment is finished, molding according to the pressure of 50MPa to obtain a second product;

s3: high-temperature carbonization treatment: and (3) loading the obtained second product into a tube furnace, heating to 220 ℃ at a heating rate of 6C/min under the condition of inert atmosphere and H2 mixed gas (nitrogen gas of 100%), preserving heat for 5 hours, directly heating to 1300 ℃ at a heating rate of 12 ℃/min after the heat preservation is finished, and preserving heat for 1 hour until carbonization is finished, thus obtaining a third product.

Comparative example 3

Comparative example 3 was different from example 3 only in that the amount of carboxymethylcellulose added was 50%, and other operations and conditions were the same as example 3.

Effect example 1

Hard carbon performance test method:

carrying out particle size test by using a Markov 3000 laser particle size distribution tester; testing the hard carbon compaction density by using an LD43.305 press; testing the interlayer spacing of graphite by XRD; na content was measured by XRF (X-ray fluorescence); the hard carbon specific surface area was measured using a Kang Da NOVA TOUCH in the united states; the electrochemical performance test procedure was as follows: the prepared hard carbon, conductive carbon black and PVDF are mixed according to the mass ratio of 94:4:2, dissolved in a certain amount of NMP, stirred for 30min, and then the slurry was applied to an aluminum foil (coating amount: 39 mg) and dried for 24h. After drying, the aluminum foil was cut into 12mm disks, and a 2032 type battery (electrolyte 1mol ^-1 NaFPO of (C) ₄ (wherein the NaFPO4/EC/DEC ratio is 8:1:1), the separator is Clgard 2400, the cathode is hard carbon, and the anode is sodium sheet) to form the sodium battery. After the assembled battery is kept stand for 24 hours, electrochemical performance test is carried out on a Xinwei battery tester (CT-ZWJ-4S-T-1U), and the first discharge specific capacity and coulombic efficiency test are carried out under the condition of 0.5C multiplying power.

The test results are shown in Table 6.

TABLE 6

Fig. 1 is a charge-discharge curve of a sodium ion battery prepared from the hard carbon negative electrode material obtained in example 1. As can be seen from fig. 1, the first charge capacity of the negative electrode material of example 1 was 438mAh/g, the first discharge capacity was 408mAh/g, and the irreversible capacity was 30mAh/g.

Claims

1. The preparation method of the asphalt-based hard carbon anode material is characterized by comprising the following steps of:

2. The method for preparing a pitch-based hard carbon anode material according to claim 1, wherein in S1, the mass of the alkali metal reagent is 5% -38% of the mass of the coal pitch;

and/or, in S2, the mass of the binder is 5-35% of the mass of the first product.

3. The method for preparing a pitch-based hard carbon negative electrode material according to claim 2, wherein in S1, the mass of the alkali metal reagent is 5%, 10%, 15%, 20%, 25%, 30% or 35% of the mass of the coal pitch;

and/or, in S2, the binder mass is 5%, 15%, 25% or 30% of the first product mass.

4. The method for producing a pitch-based hard carbon anode material according to claim 1, wherein the method for producing a pitch-based hard carbon anode material satisfies one or more of the following conditions (1) to (8):

(1) in S1, the softening point of the coal tar pitch is 150-280 ℃, such as 180 ℃;

(2) in S1, the coking value of the coal tar pitch is 60% -82%, such as 61%;

(3) s1, the particle size of the coal tar pitch is below 150 mu m;

(4) in S1, the alkali metal reagent is hydroxide, carbonate or bicarbonate of Na metal;

(5) in S1, the temperature of the oxidative crosslinking reaction is 350-600deg.C, preferably 400-550deg.C, such as 450deg.C;

(6) in S1, the time of the oxidative crosslinking reaction is 1 to 6 hours, preferably 2 to 4 hours, for example 3 hours;

(7) in S1, the sodium content of the first product is 30ppm-100ppm, such as 48ppm; and, a step of, in the first embodiment,

(8) in S1, the oxygen content of the first product is 5.4% -38.7%, such as 24.6%.

5. The method for producing a pitch-based hard carbon anode material according to claim 1, wherein the method for producing a pitch-based hard carbon anode material satisfies one or more of the following conditions (1) to (4):

(1) s2, adding the binder in the form of a binder solution;

(2) in S2, the binder is one or more of carboxymethyl cellulose, starch and sodium lignin sulfonate;

(3) s2, kneading for 10-80 min; and, a step of, in the first embodiment,

(4) and S2, the compression molding pressure is 30-120 MPa.

6. The method for producing a pitch-based hard carbon anode material according to claim 5, wherein the method for producing a pitch-based hard carbon anode material satisfies one or more of the following conditions (1) to (5):

(1) in S2, when the binder is added in the form of a binder solution, the concentration of the binder solution is 0.1 to 1.5%, preferably 0.2% to 1.3%, for example 0.8% or 1%;

the viscosity of the binder solution is 400-5000 mPa-s, for example 2890 mPa-s;

(2) the degree of substitution of the carboxymethyl cellulose is 0.4 to 0.9, for example 0.6 to 0.8;

(3) the carboxymethyl cellulose has a pH of 6 to 8, for example 7.8;

(4) s2, kneading for 20-60 min, such as 20min, 25min, 30min, 40min, 45min or 50min; and, a step of, in the first embodiment,

(5) in S2, the pressure of the compression molding is 60MPa to 100MPa, for example 60MPa, 70MPa, 80MPa, 90MPa or 100MPa.

7. The method for producing a pitch-based hard carbon anode material according to claim 1, wherein the method for producing a pitch-based hard carbon anode material satisfies one or more of the following conditions (1) to (8):

(1) s3, heating to the dehydration temperature at a rate of 0.5 ℃/min-5 ℃/min;

(2) s3, in the dehydration treatment process, the dehydration time is 1-3h;

(3) s3, in the dehydration treatment process, the dehydration temperature is 100-240 ℃;

(4) s3, heating to the carbonization treatment temperature at a rate of 5-10 ℃/min;

(5) s3, in the carbonization treatment process, the carbonization time is 1-5h;

(6) s3, in the carbonization treatment process, the carbonization temperature is 900-1290 ℃;

(7) s3, the dehydration treatment and the carbonization treatment are carried out in inert atmosphere and H ₂ Under the mixed gas; and, a step of, in the first embodiment,

(8) in S3, the Na content of the asphalt-based hard carbon anode material is 60-300ppm.

8. The method for producing a pitch-based hard carbon anode material according to claim 7, wherein the method for producing a pitch-based hard carbon anode material satisfies one or more of the following conditions (1) to (6):

(1) s3, heating to the dehydration temperature at a speed of 2 ℃/min;

(2) s3, in the dehydration treatment process, the dehydration temperature is 200 ℃;

(3) s3, in the carbonization treatment process, the carbonization time is 2-4 hours, such as 3 hours;

(4) s3, in the carbonization treatment process, the carbonization temperature is 950-1250 ℃;

(5) the inert atmosphere and H ₂ In the mixed gas, H ₂ Is 2-20%, such as 2%, 5%, 8%, 10%, 15% or 18%, by volume, the percentages being H ₂ The volume percentage of the mixed gas is calculated; and, a step of, in the first embodiment,

(6) in S3, the Na content of the asphalt-based hard carbon anode material is 180ppm.

9. A pitch-based hard carbon anode material produced by the production method according to any one of claims 1 to 8.

10. Use of the pitch-based hard carbon anode material of claim 9 in the field of sodium ion batteries.