CN115818617A

CN115818617A - Sodium ion battery negative electrode active material prepared from high-sulfur coke, and preparation method and application thereof

Info

Publication number: CN115818617A
Application number: CN202211501892.4A
Authority: CN
Inventors: 文康; 周进辉; 罗顺; 蒋凯
Original assignee: Hunan Chenyu Fuji New Energy Technology Co ltd
Current assignee: Hunan Chenyu Fuji New Energy Technology Co ltd
Priority date: 2022-11-28
Filing date: 2022-11-28
Publication date: 2023-03-21

Abstract

The invention belongs to the technical field of negative electrode materials of sodium ion secondary batteries, and particularly relates to a method for preparing a negative electrode active material of a sodium ion battery by using high-sulfur coke, wherein the high-sulfur coke and a transition metal salt are subjected to ammoniation roasting in an ammonia-containing atmosphere in advance, then are calcined under negative pressure, and are washed and dried to prepare the high-sulfur-based negative electrode active material; the sulfur content in the high sulfur coke is greater than or equal to 3wt.%; the temperature in the ammoniation roasting stage is 500-700 ℃; the calcining temperature is 800-1200 ℃. The invention also relates to a material prepared by the preparation method and application of the material in a sodium ion battery. The preparation method can solve the problems in the preparation of the sodium electric cathode by using the high-sulfur coke, and can obtain better sodium electric performance.

Description

Sodium ion battery negative electrode active material prepared from high-sulfur coke, and preparation method and application thereof

Technical Field

The invention belongs to the technical field of electrode materials of sodium-ion batteries, and particularly relates to the field of negative electrode active materials of sodium-ion batteries.

Background

The lithium ion battery has the advantages of small pollution, good cycle performance, high energy density and the like, and is widely applied to the fields of 3C consumer electronics, electric automobiles and the like. But due to rapid increase in demand of lithium ion batteries, shortage of lithium resources, battery safety problems, etc., people are prompted to find and develop new rechargeable batteries. Sodium has the advantages of low price, large resource quantity and the like, and is considered by scientists to be one of the most potential novel energy storage battery systems capable of replacing lithium ion batteries. The cathode material is an important component of the sodium ion battery, and the performance of the cathode material has important influence on the overall performance of the battery, such as energy density, power density, cycle life and the like. Graphite is a common negative electrode material for current commercial lithium ion batteries, but sodium ions cannot be reversibly embedded between graphite layers because the radius of the sodium ions is larger than that of the lithium ions, so that the graphite negative electrode suitable for the lithium ion battery cannot be suitable for a sodium ion battery system. The non-graphitized carbon material has received extensive attention from researchers due to the advantages of large carbon layer spacing, abundant sodium storage active sites and the like. However, the non-graphitized carbon material has low electronic conductivity, which greatly limits the dynamic performance of the non-graphitized carbon material applied in a sodium ion battery system.

Petroleum coke is a widely used raw material of an artificial graphite cathode material for a lithium ion battery, in particular low-sulfur petroleum coke, and the consumption of the low-sulfur petroleum coke is increased and the cost is increased due to the expansion of the application market of the lithium ion battery at present. The low-cost high-sulfur petroleum coke cannot realize high value-added application.

Therefore, it is urgently needed to develop a new negative electrode material based on low-cost high-sulfur petroleum coke and a preparation method thereof, and to realize a new process for preparing a high-performance carbon negative electrode material for a sodium-ion battery under a low energy consumption condition.

Disclosure of Invention

In view of the defects of the prior art, the first object of the present invention is to provide a method for preparing a sodium ion battery negative active material (also referred to as an active material for short in the present invention) by using high-sulfur coke, and the method is used for preparing a sodium ion battery negative active material with high electrochemical performance based on high-sulfur coke.

The second purpose of the invention is to provide the active material prepared by the preparation method and the application thereof in a sodium-ion battery.

The third purpose of the invention is to provide a sodium-ion battery containing the active material, a positive electrode thereof and a positive electrode material.

The high-sulfur coke has high sulfur content and mainly exists in the phase form of organic sulfur, the difficulty of treating and recycling harmful sulfur in the high-sulfur coke is high, and the conventional low-sulfur coke negative electrode preparation process is difficult to transfer to the preparation of a high-sulfur coke-based negative electrode. In addition, due to the presence of high organic sulfur in the high sulfur coke, it is difficult to construct microscopic pores, interlayer structures, active sites, and conductive networks that are adapted for sodium ion intercalation-deintercalation. Aiming at the problems that the high-sulfur coke is difficult to match with the use requirement of sodium ions, the sodium electrical property of the prepared material is not ideal and the like, the invention provides the following solutions:

a method for preparing a sodium ion battery cathode active material from high-sulfur coke comprises the steps of carrying out ammoniation roasting on the high-sulfur coke and transition metal salt in an ammonia-containing atmosphere in advance, then carrying out roasting under negative pressure, and then washing and drying to prepare the high-sulfur-based cathode active material;

the sulfur content in the high sulfur coke is greater than or equal to 3wt.%;

the temperature in the ammoniation roasting stage is 500-700 ℃; the calcining temperature is 800-1500 ℃.

Aiming at the problem that the high-sulfur coke is difficult to prepare the negative active material of the sodium ion battery, the invention innovatively carries out catalytic gas-solid conversion on the high-sulfur coke and transition metal salt in the atmosphere containing ammonia gas, and further cooperates with the combined control of ammoniation roasting temperature and negative pressure roasting process and parameters, so that the synergy can be realized, the effective conversion of harmful sulfur in the high-sulfur coke can be effectively regulated and controlled, the sulfur conversion behavior can be facilitated to construct a micro-pore structure, an interlayer and an active site matched with sodium ions, a local graphite conductive network is favorable for improving the embedding-de-embedding, storage and transmission capacity of the sodium ions, and the electrochemical performance of the sodium ion battery is further improved.

In the invention, the high-sulfur coke is a byproduct obtained by treating residual oil through a coking process in the crude oil refining process.

In the present invention, the particle size of the high-sulfur coke is not particularly limited, and for example, the D50 particle size thereof is controlled to 4 to 12 μm;

preferably, the sulfur content in the high sulfur coke is 3.5 to 8wt.%, and further preferably 4.5 to 6.5wt.% in view of the production performance and effect.

In the invention, the high-sulfur coke is subjected to gas-solid ammoniation roasting under the assistance of the transition metal salt, so that the sulfur conversion behavior of the high-sulfur coke can be synergistically regulated and controlled, and in addition, the interlayer and active sites matched with the sodium ions can be unexpectedly constructed by matching with the joint control of temperature, thereby being beneficial to improving the performance of the sodium ion battery.

Preferably, the transition metal salt is at least one of iron salt, cobalt salt, nickel salt and manganese salt;

preferably, the transition metal salt is at least one of chloride, nitrate, sulfate and organic acid salt of transition metal, and further preferably one or more of nickel oxalate, cobalt oxalate, iron oxalate, nickel nitrate, cobalt nitrate and ferric chloride;

further preferably, the transition metal salt is a metal salt of cobalt and nickel; more preferably a complex salt of nickel and cobalt, such as a mixture of nickel oxalate and cobalt nitrate. In the invention, the ammoniation roasting-negative pressure roasting treatment is carried out under the assistance of the preferable Co-Ni composite salt, which is beneficial to further improving the performance of the high-sulfur sodium pyro-based electric negative electrode material in a synergistic way.

Preferably, the weight ratio of the high-sulfur coke to the transition metal salt is 100:2 to 20, more preferably 100.

In the present invention, the high sulfur coke and the transition metal salt may be mixed in a solid phase or a liquid phase.

Preferably, the high-sulfur coke and the transition metal salt are subjected to liquid phase compounding under negative pressure, and then subjected to spray drying or evaporation treatment to prepare the compound. The research of the invention finds that the synergistic effect of ammoniation roasting and negative pressure roasting can be further improved unexpectedly by adopting the negative pressure liquid phase treatment and matching with the spraying treatment, the sodium ion adaptation effect can be further improved synergistically, and the sodium electrical property of the material can be further improved.

Preferably, the solvent of the liquid phase compounding stage is, for example, water, a mixed solvent of water and an organic solvent, and the organic solvent is a solvent miscible with water. In the liquid phase combination stage, the concentration of the transition metal salt is not particularly limited, and may be, for example, 0.1 to 3M.

Preferably, the ammonia-containing atmosphere is a mixed gas of ammonia and ammonia-protective gas;

preferably, the volume content of ammonia in the ammonia-containing atmosphere is 5 to 20%, preferably 10 to 15% by volume.

More preferably, the ammonia-containing atmosphere further contains hydrogen, and the volume content of hydrogen is preferably 2 to 10%, and still more preferably 3 to 6% by volume.

Preferably, the temperature in the ammoniation roasting stage is 600-650 ℃;

preferably, the ammoniation roasting stage is carried out at atmospheric pressure;

preferably, the time for ammoniation roasting is 2-6 h.

In the invention, under the ammoniation roasting, the subsequent negative pressure roasting process and the temperature combined control are further matched, the conversion behavior of sulfur in the high-sulfur coke can be effectively utilized, the interlayer and active site adapted to sodium ions can be further constructed, and the electrochemical performance of the sodium ion battery is improved.

Preferably, the negative pressure is 20 to 500Pa;

preferably, the temperature of calcination is 900 to 1100 ℃;

preferably, the calcination time is 2 to 4 hours;

preferably, the washing process comprises an acid washing, water washing process.

The invention discloses a preferable high-sulfur petroleum coke-based carbon negative electrode material of a sodium ion battery and a preparation method thereof, and the preferable high-sulfur petroleum coke-based carbon negative electrode material comprises the following steps:

step (1): mixing high-sulfur petroleum coke and transition metal salt in certain proportion;

step (2): placing the dried mixture obtained in the step (1) in an atmosphere furnace for secondary heat treatment, and introducing ammonia-containing gas into the atmosphere furnace; wherein, the temperature of the first stage heat treatment is 500-700 ℃, and the condition of normal pressure is adopted; the second stage of heat treatment is carried out under the condition of negative pressure, and the heat preservation temperature is 800-1200 ℃;

and (3): and (3) carrying out acid washing, water washing and drying on the product prepared in the step (2) to prepare the high-performance carbon negative electrode material for the sodium-ion battery. The acid washing is to stir the powder obtained by the heat treatment in hydrochloric acid, nitric acid, sulfuric acid and other acids, wherein the concentration of the acid solution is 0.2-2M, and the liquid-solid ratio (ml/g) is 2-5: 1, the reaction temperature is 20-60 ℃, the reaction time is 1-3 h, and the obtained powder is washed and dried conventionally after the reaction is finished.

The preparation method is beneficial to constructing the storage site and the transmission network which are adapted to the sodium ions, is beneficial to the embedding and the de-embedding of the sodium ions, and can improve the specific capacity, the rate capability and the cycling stability when the preparation method is applied to the sodium ion battery.

The invention also provides the active material prepared by the preparation method.

According to the method, special microscopic physical and chemical structural characteristics can be constructed, and the control of the method can realize synergy, improve the adaptation effect of the prepared material on sodium ions, and contribute to improving the electrochemical performance of the sodium ion battery, such as the capacity, the multiplying power and the cycling stability which are excellent unexpectedly.

The invention also provides application of the active material prepared by the preparation method, and the sodium-ion battery, the cathode thereof and the cathode material thereof are prepared by using the active material as the active material based on a conventional method.

The composite material is preferably used as a negative active material and is used for being compounded with a conductive agent and a binder to prepare a negative material. The conductive agent and the binder are all materials known in the industry.

In a further preferable application, the negative electrode material is arranged on the surface of a negative electrode current collector and used for preparing a negative electrode. The negative electrode may be formed by applying the negative electrode material of the present invention to a current collector by a conventional method, for example, by a coating method. The current collector is any material known in the industry.

In a further preferred application, the negative electrode, the positive electrode, the separator and the electrolyte are assembled into a sodium ion secondary battery.

A sodium ion battery comprises the high-sulfur petroleum coke-based carbon negative electrode active material prepared by the preparation method.

In the sodium ion battery of the present invention, the processes and components other than the active material prepared by the method of the present invention may be conventional.

The technical scheme of the invention has the beneficial effects that:

(1) The invention innovatively carries out catalytic gas-solid conversion on the high-sulfur coke and the transition metal salt in the atmosphere containing ammonia gas, and further cooperates with the combined control of the ammoniation roasting temperature and the negative pressure roasting process and parameters, so that the synergy can be realized, the effective conversion of harmful sulfur in the high-sulfur coke can be effectively regulated and controlled, the sulfur conversion behavior can be facilitated to construct a micro-pore structure, an interlayer and an active site matched with sodium ions, a local graphite conductive network is favorable for improving the embedding-deinsertion, storage and transmission capability of the sodium ions, and the electrochemical performance of the sodium ion battery is further improved.

(2) Under the combined innovation of transition metal assisted ammoniation roasting-negative pressure roasting, the combination of Co-Ni compound, negative pressure liquid phase compound and ammoniation roasting process of hydrogen-ammonia-containing compound atmosphere is further matched, so that the synergy can be further realized, the problem that the high-sulfur coke is difficult to prepare the cathode with sodium electricity adaptation can be further solved, and better sodium electricity performance can be obtained.

(3) The method has the advantages of simple process, easy realization, cheap and easily obtained raw materials, simple preparation flow and environment-friendly process.

Drawings

FIG. 1 is an SEM photograph of the final carbon material of example 1;

FIG. 2 is a TEM image of the final carbon material obtained in example 1.

Detailed Description

The specific procedures of the present invention are illustrated below by way of examples, it being understood that these examples are intended to illustrate the invention and are not intended to limit the scope of the invention in any way. Various procedures and methods not described in detail herein are conventional methods well known in the art.

Example 1

Crushing and screening high-sulfur petroleum coke (with the sulfur content of 5.8 wt.%), and taking 100g of powder with the median particle size of 5.6 microns; weighing 10g of cobalt nitrate, placing the two kinds of powder into a mixer, uniformly mixing, and then placing the mixture into an atmosphere furnace for ammoniation heat treatment and negative pressure heat treatment, wherein the steps are as follows:

ammoniation heat treatment: firstly, introducing mixed gas of 10% ammonia gas and 90% argon gas into a furnace, heating to 600 ℃ at the speed of 5 ℃/min (marked as T1), and preserving heat for 3 hours at the temperature;

negative pressure heat treatment: heating to 800 deg.C (labeled T2) at 5 deg.C/min, vacuumizing to make the vacuum degree of the system 100Pa (labeled P), maintaining the temperature for 3 hr, cooling to room temperature, and taking out the heat-treated powder.

Preparing a hydrochloric acid solution with the concentration of 1M, placing the powder subjected to heat treatment in the hydrochloric acid solution, stirring and reacting for 1 hour at the temperature of 40 ℃, filtering, washing with water until the powder is neutral, and drying to obtain the active material.

The physical and chemical results of the material are as follows: the specific surface area is 8.6m ² The fixed carbon content was 99.98%.

Slurry coating of an active material, conductive carbon black and Sodium Alginate (SA) in a mass ratio of 90 ₆ The electrochemical performance of the CR2025 button cell was measured at room temperature in a voltage range of 0.01 to 3.0V using EC/DEC (volume ratio 1) as an electrolyte and glass fiber as a separator, and the charge-discharge test current density was 0.1C (1c = 300ma/g). The first reversible capacity was recorded as 357mAh/g, the first coulombic efficiency as 88.2%, and the capacity retention after 500 cycles was 89.2%. The reversible specific capacity of the material is 259mAh/g after rapid charge and discharge under the 2C condition.

Example 2

Compared with example 1, the difference is only that the type and the dosage of the transition metal salt are changed, and the experimental groups are respectively as follows:

group A: the transition metal salt is 10g of nickel oxalate;

group B: the transition metal salt is 2g of cobalt nitrate and 8g of nickel oxalate;

group C: the transition metal salt is ferric chloride, and the dosage is 10g;

group D: 2g of cobalt nitrate and 8g of nickel oxalate were dissolved in 1L of water, 100g of high-sulfur petroleum coke was dispersed in the solution, and the solution was treated under a negative pressure of 0.1atm, and then dried by spray drying to obtain a dry powder, and the same post-treatment as in example 1 was continued.

Group E: the dosage of the transition metal salt is 5g;

the battery assembly and electrochemical testing were performed using the method of example 1, with the results:

group A: the first reversible capacity of 0.1C is 361mAh/g, the first coulombic efficiency is 88.9 percent, and the capacity retention rate is 89.7 percent after 500 cycles. The reversible specific capacity is 261mAh/g when the charge and discharge are carried out rapidly under the 2C condition.

Group B: the first reversible capacity of 0.1C is 366mAh/g, the first coulombic efficiency is 91.1%, and the capacity retention rate is 90.8% after 500 circulations. The reversible specific capacity is 268mAh/g.

Group C: the first reversible capacity of 0.1C is 354mAh/g, the first coulombic efficiency is 87.5 percent, and the capacity retention rate is 88.1 percent after 500 cycles. The reversible specific capacity is 253mAh/g after rapid charge and discharge under the condition of 2C.

Group D: the first reversible capacity of 0.1C is 371mAh/g, the first coulombic efficiency is 92.3 percent, and the capacity retention rate after 500 cycles is 93.3 percent. The reversible specific capacity is 276mAh/g when the lithium ion battery is charged and discharged rapidly under the 2C condition.

Group E: the first reversible capacity of 0.1C is 358mAh/g, the first coulombic efficiency is 88.2 percent, and the capacity retention rate is 89.3 percent after 500 cycles. The reversible specific capacity is 260mAh/g when the charge and the discharge are rapidly carried out under the 2C condition.

As is clear from example 1 and groups a, B, and C, it is found that the combination of cobalt nitrate and nickel oxalate, which is preferable, can achieve further synergy and can achieve more excellent performance, and that the combination of negative pressure liquid phase combination and spray treatment, which is preferable, can further improve the sodium electric performance, as compared with group D.

Example 3

The only differences from example 1 are that the atmosphere in the ammoniation heat treatment stage (T1 soak stage) is: group A: the atmosphere of the mixed gas is ammonia-argon gas mixed gas, wherein the system content of ammonia is 15v%, and the balance is argon gas.

Group B: the atmosphere of the mixed gas is ammonia-hydrogen-argon mixed gas, wherein the system content of ammonia is 10%, the hydrogen content is 5%, and the balance is argon.

The results of the measurements carried out in example 1 were:

group A: the first reversible capacity of 0.1C is 359mAh/g, the first coulombic efficiency is 89.2 percent, and the capacity retention rate is 90.8 percent after 500 cycles. The reversible specific capacity is 265mAh/g under the condition of 2C.

Group B: the first reversible capacity of 0.1C is 365mAh/g, the first coulombic efficiency is 88.9 percent, and the capacity retention rate is 91.2 percent after 500 cycles. The reversible specific capacity is 268mAh/g.

Compared with example 1, the ammoniation treatment in the hydrogen-containing atmosphere can be unexpectedly synergistic with other steps to further synergistically improve the sodium electric properties.

Example 4

The only difference compared to example 1 is that the temperature of T1 was varied to:

group A: t1 is 500 ℃ and the holding time at this temperature is 5H.

Group B: t1 is 700 ℃ and the holding time at this temperature is 3H.

Group C: t1 is 650 ℃ and the incubation time at this temperature is 4H.

group A: the first reversible capacity of 0.1C is 360mAh/g, the first coulombic efficiency is 88.2%, and the capacity retention rate is 91.1% after 500 circulations. The reversible specific capacity is 265mAh/g when the lithium ion battery is charged and discharged rapidly under the 2C condition.

Group B: the first reversible capacity of 0.1C is 359mAh/g, the first coulombic efficiency is 88.6 percent, and the capacity retention rate is 90.9 percent after 500 cycles. The reversible specific capacity is 263mAh/g.

Group C: the first reversible capacity of 0.1C is 362mAh/g, the first coulombic efficiency is 88.9 percent, and the capacity retention rate is 91.3 percent after 500 cycles. The reversible specific capacity is 269mAh/g by rapid charge and discharge under the condition of 2C.

Example 5

The only difference compared to example 1 is that the temperature of T2 was varied to:

group A: t2 is 850 ℃, the holding time at the temperature is 4H, and P is 20Pa.

Group B: t2 is 1000 ℃, the holding time at this temperature is 2H, and P is 100Pa.

Group C: t2 is 900 ℃, the holding time at this temperature is 3H, and P is 50Pa.

group A: the first reversible capacity is 359mAh/g, the first coulombic efficiency is 88.7 percent, and the capacity retention rate is 89.4 percent after 500 cycles. The reversible specific capacity is 268mAh/g under the condition of 2C.

Group B: the first reversible capacity is 365mAh/g, the first coulombic efficiency is 88.8 percent, and the capacity retention rate is 90.2 percent after 500 cycles. The material is rapidly charged and discharged under the condition of 2C, and the reversible specific capacity is 267mAh/g.

Group C: the first reversible capacity is 363mAh/g, the first coulombic efficiency is 89.1%, and the capacity retention rate is 91.4% after 500 cycles. The reversible specific capacity is 266mAh/g.

Comparative example 1:

the only difference compared to comparative example 1 is that no cobalt nitrate was added and the other operations and parameters were the same as in example 1.

The results of the measurements carried out as in example 1 are: the first reversible capacity is 212mAh/g, and the capacity retention rate is 42% after 500 cycles. The reversible specific capacity is 117mAh/g when the lithium ion battery is rapidly charged and discharged under the 2C condition.

Comparative example 2

The only difference compared to comparative example 1 is that equal weight of sodium nitrate was used instead of cobalt nitrate and the other operations and parameters were the same as in example 1.

The results of the measurements carried out as in example 1 were:

the first reversible capacity is 228mAh/g, and the capacity retention rate is 47% after 500 cycles. The reversible specific capacity is 122mAh/g when the lithium ion battery is charged and discharged rapidly under the 2C condition.

Comparative example 3:

the only difference compared to comparative example 1 is that the atmosphere in the T1 heat treatment stage does not contain ammonia, but pure Ar, and the other operations and parameters are the same as those of example 1.

The results of the measurements carried out as in example 1 were: the first reversible capacity is 252mAh/g, and the capacity retention rate is 39% after 500 cycles. The reversible specific capacity is 118mAh/g.

Comparative example 4

Compared with example 1, the difference is that 100g of high-sulfur petroleum coke (same as example 1), 10g of cobalt nitrate and 5g of ammonium chloride are placed in a mixer to be uniformly mixed, then solid-solid reaction is carried out under Ar atmosphere and T1 temperature, and then subsequent negative pressure heat treatment and subsequent treatment are carried out.

The results of the measurements carried out as in example 1 were: the first reversible capacity is 287mAh/g, and the capacity retention rate is 76% after 500 cycles. The reversible specific capacity is 141mAh/g when the lithium ion battery is charged and discharged rapidly under the 2C condition.

Compared with example 1, the performance was significantly reduced without performing a continuous gas-solid transition in an ammonia-containing atmosphere.

Comparative example 5

Compared with example 1, the difference is only that the temperature of T1 is 350 ℃; the other operations and parameters were the same as in example 1.

The results of the measurements carried out as in example 1 were: the first reversible capacity is 263mAh/g, and the capacity retention rate is 62% after 500 cycles. The reversible specific capacity is 123mAh/g.

Comparative example 6:

the difference from comparative example 1 is only that the T2 heat treatment process is an atmospheric process, that is, the pressure of the T2 stage holding treatment stage is 1atm, and other operations and parameters are the same as those of example 1.

The results of the measurements carried out according to example 1 are:

the first reversible capacity was recorded to be 252mAh/g, and the capacity retention after 500 cycles was 47%. The reversible specific capacity is 103mAh/g under the condition of 2C.

Claims

1. The method for preparing the sodium ion battery cathode active material by using the high-sulfur coke is characterized in that the high-sulfur coke and transition metal salt are subjected to ammoniation roasting in an ammonia-containing atmosphere in advance, then are calcined under negative pressure, and then are washed and dried to prepare the high-sulfur-based cathode active material;

the sulfur content in the high sulfur coke is greater than or equal to 3wt.%;

the temperature in the ammoniation roasting stage is 500-700 ℃; the calcining temperature is 800-1200 ℃.

2. The method for preparing the sodium-ion battery negative active material by using the high-sulfur coke as claimed in claim 1, wherein the D50 particle size of the high-sulfur coke is controlled to be 4-12 μm;

preferably, the sulfur content in the high sulfur coke is 3.5 to 8wt.%.

3. The method for preparing the negative active material of the sodium-ion battery by using the high-sulfur coke as claimed in claim 1, wherein the transition metal salt is at least one of iron salt, cobalt salt, nickel salt and manganese salt;

preferably, the transition metal salt is one or more of nickel oxalate, cobalt oxalate, ferric oxalate, nickel nitrate, cobalt nitrate and ferric chloride;

preferably, the transition metal salt is a metal salt of cobalt and nickel; more preferably a complex salt of nickel and cobalt.

4. The method for preparing the negative active material of the sodium-ion battery by using the high-sulfur coke as claimed in claim 1 or 3, wherein the weight ratio of the high-sulfur coke to the transition metal salt is 100:2 to 20;

preferably, the high-sulfur coke and the transition metal salt are subjected to liquid phase compounding under negative pressure, and then subjected to spray drying or evaporation treatment to prepare a compound, and then subjected to ammoniation roasting.

5. The method for preparing the sodium-ion battery negative electrode active material by using the high-sulfur coke as claimed in claim 1, wherein the ammonia gas-containing atmosphere is a mixed gas of ammonia gas and ammonia gas-protective gas;

preferably, in the ammonia-containing atmosphere, the volume content of ammonia is 5-20%;

more preferably, the ammonia-containing atmosphere further contains hydrogen, and the volume content of the hydrogen is preferably 2 to 10%.

6. The method for preparing the sodium-ion battery negative active material by using the high-sulfur coke as claimed in claim 1, wherein the temperature in the ammoniation roasting stage is 600-650 ℃;

preferably, the time for ammoniation roasting is 2-6 h.

7. The method for preparing the negative active material of the sodium-ion battery by using the high-sulfur coke as claimed in claim 1, wherein the negative pressure is 20 to 500Pa;

preferably, the temperature of calcination is 900 to 1100 ℃;

preferably, the calcination time is 2 to 4 hours;

8. The high-sulfur coke prepared by the preparation method of any one of claims 1 to 7 is used for preparing a negative electrode active material of a sodium ion battery.

9. The application of the high-sulfur coke prepared by the preparation method of any one of claims 1 to 7 in preparing the negative electrode active material of the sodium-ion battery is characterized in that the high-sulfur coke is used as the negative electrode active material for preparing the sodium-ion battery.

10. A sodium ion battery, characterized in that the high-sulfur coke prepared by the preparation method of any one of claims 1 to 7 is compounded in the positive electrode to prepare the negative electrode active material of the sodium ion battery.