A method for producing single-granular negative electrode materials from medium-sulfur coke

Abstract

The invention belongs to the technical field of batteries, and discloses a production method for a single-particle negative electrode material produced from medium-sulfur coke. The steps of producing the single-particle negative electrode material from the medium-sulfur coke are as follows: S1, calcination: heating and calcining the medium-sulfur coke; the invention provides a production method for a single-particle negative electrode material produced from medium-sulfur coke, by heating and calcining the medium-sulfur coke, cooling the calcined medium-sulfur coke, crushing and screening the crushed medium-sulfur coke to obtain medium-sulfur coke powder, and obtaining a single-particle negative electrode material, thereby improving the production efficiency of product graphitization and ensuring the production quality of the product, so that the product has a higher charge and discharge capacity and charge and discharge efficiency, optimizing the electrical properties of the graphite negative electrode material, and screening the medium-sulfur coke negative electrode material to make it in a loose state, avoiding the agglomeration of powder particles, ensuring that the particle size meets the production needs, and optimizing the particle size range distribution of the powder particles, so that the particle size processing is more reasonable and efficient, and the work efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular is a method for producing single-time particle negative electrode materials from medium-sulfur coke. Background Art

[0002] The vacuum residue of petroleum is cracked and coked at 500-550℃ in a coking unit to produce black solid coke. Medium-sulfur coke can be divided into high-sulfur coke (sulfur content higher than 4%), medium-sulfur coke (sulfur content 2% to 4%) and low-sulfur coke (sulfur content lower than 2%) according to the sulfur content. As a new generation of chemical storage batteries, lithium-ion batteries have high operating voltage, large volume and energy density, stable charge and discharge voltage platform, long service life, low temperature resistance, and are environmentally friendly. They have been widely used in laptops, communication tools, electric vehicles and other fields.

[0003] At present, the negative electrode material of lithium-ion batteries usually uses graphite as raw material. Graphite includes natural graphite materials and artificial graphite materials. Natural graphite mainly exists in associated graphite deposits. Although my country's natural graphite reserves and output are both ranked first in the world, natural graphite is a non-renewable mineral resource. Moreover, natural graphite mainly exists in associated graphite deposits. It needs to be mined, selected, purified, shaped and graded, etc. It is greatly affected by natural deposits, cost control and product quality. Therefore, low-cost, high-performance artificial graphite is a new source of graphite negative electrode materials for lithium batteries. Summary of the invention

[0004] In order to solve the problems raised in the above-mentioned background technology, the present invention provides a production method of single-granular negative electrode material from medium-sulfur coke, by heating and calcining the medium-sulfur coke, cooling the calcined medium-sulfur coke, crushing and screening the crushed medium-sulfur coke to obtain medium-sulfur coke powder, stirring and mixing the medium-sulfur coke powder with a binding material, and heating the mixture to obtain a negative electrode material, heating the negative electrode material to a temperature of 400-600°C for a constant temperature, and maintaining it for 5 hours to obtain a single-granular negative electrode material, thereby improving the production efficiency of product graphitization and ensuring the production quality of the product, so that the product has higher charge and discharge capacity and charge and discharge efficiency, optimizing the electrical properties of the graphite negative electrode material, making the particle size processing more reasonable and efficient, and achieving the advantage of improving work efficiency.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for producing a single particle negative electrode material from medium-sulfur coke, wherein the steps of producing a single particle negative electrode material from medium-sulfur coke are as follows:

[0006] S1. Calcination: heating and calcining the medium-sulfur coke;

[0007] S2. Crushing: The calcined medium-sulfur coke is cooled and crushed and sieved;

[0008] S3, stirring and mixing: stirring and mixing the medium-sulfur coke powder and the binding material, and heating the mixture to obtain a negative electrode material;

[0009] S4, heating: heating and cooling the negative electrode material;

[0010] S5. Graphite treatment: obtaining a single-particle negative electrode material.

[0011] Preferably, the medium-sulfur coke is calcined at a temperature of 200°C / min, and the temperature is controlled at 1500°C-1600°C for 2 hours.

[0012] Preferably, the medium-sulfur coke is crushed by a jaw crusher, and the crushed medium-sulfur coke is pulverized and sieved, and the pulverized particles of the medium-sulfur coke are 50 um.

[0013] Preferably, the binder material in S3 is asphalt.

[0014] Preferably, asphalt material is added during the stirring process of the medium-sulfur coke powder, and the ratio of the medium-sulfur coke powder to the asphalt material is 20:12. After the addition is completed, the stirring speed is controlled at 2000 rpm and the stirring is performed for 1-2 hours.

[0015] Preferably, in S4, the first heating rate is 20-30°C / min, the temperature is raised to 500°C, and maintained for 1 hour, and the second heating rate is 80-95°C / min, the temperature is raised to 1200°C, and maintained for 4-5 hours.

[0016] Preferably, the temperature of the negative electrode material is lowered to 400-600° C. after heating and maintained at a constant temperature for 5 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The invention provides a production method of single-particle negative electrode material from medium-sulfur coke, comprising the steps of heating and calcining the medium-sulfur coke, cooling the calcined medium-sulfur coke, pulverizing and screening the crushed medium-sulfur coke to obtain medium-sulfur coke powder, stirring and mixing the medium-sulfur coke powder and a bonding material, heating the mixture to obtain a negative electrode material, heating the negative electrode material to a temperature of 400-600 DEG C for constant temperature maintenance for 5 hours to obtain a single-particle negative electrode material, thereby improving the production efficiency of product graphitization and ensuring the production quality of the product, making the product have higher charge and discharge capacity and charge and discharge efficiency, optimizing the electrical properties of the graphite negative electrode material, and making the medium-sulfur coke negative electrode material in a loose state by screening treatment, avoiding the agglomeration of powder particles, ensuring that the particle size meets the production needs, and optimizing the particle size range distribution of the powder particles, making the particle size treatment more reasonable and efficient, and improving the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention; DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The present invention provides a method for producing a single-granular negative electrode material from medium-sulfur coke. The steps of producing a single-granular negative electrode material from medium-sulfur coke are as follows:

[0022] S1. Calcination: heating and calcining the medium-sulfur coke;

[0023] S2. Crushing: The calcined medium-sulfur coke is cooled and crushed and sieved;

[0024] S3, stirring and mixing: stirring and mixing the medium-sulfur coke powder and the binding material, and heating the mixture to obtain a negative electrode material;

[0025] S4, heating: heating and cooling the negative electrode material;

[0026] S5, graphite treatment: obtaining a single particle negative electrode material;

[0027] The medium-sulfur coke is heated and calcined at a temperature of 200°C / min, and the temperature is controlled to be 1500°C-1600°C, and maintained for 2 hours. The calcined medium-sulfur coke is cooled and crushed by a jaw crusher. The crushed medium-sulfur coke is pulverized and screened, and the pulverized particles are 50-60um to obtain medium-sulfur coke powder. The medium-sulfur coke powder is stirred and mixed with a bonding material, and the ratio of the medium-sulfur coke powder to the asphalt material is 20:12. After the addition is completed, the stirring speed is controlled to 2000 rpm, and the stirring is performed for 1-2 hours. The mixture is heated to obtain a negative electrode material. The negative electrode material is heated at a first heating rate of 20-30°C / min, and the temperature is raised to 500°C and maintained for 1 hour. The second heating rate is 80-95°C / min, and the temperature is raised to 1200°C and maintained for 4-5 hours. The temperature is reduced to 400-600°C for constant temperature and maintained for 5 hours to obtain a single particle negative electrode material.

[0028] After the medium-sulfur coke and asphalt coke were graphitized at 1600℃, it was found that after 50 times of repeated charge and discharge, the lithium insertion capacity of the graphitized medium-sulfur coke could be stabilized at 500mAh / g, while that of the graphitized asphalt coke was only 360mAh / g. The raw materials of the medium-sulfur coke are purified, and a wide-area intermediate phase can be formed during the coking process. In the end, the medium-sulfur coke is easier to graphitize and has a higher degree of graphitization. Graphite has good conductivity, a layered structure suitable for lithium insertion and deintercalation, and good cycle performance.

[0029] Among them, the calcination temperature of medium sulfur coke is 200℃ / min, the temperature is controlled at 1500℃-1600℃, and maintained for 2h;

[0030] Medium-sulfur coke is a black solid coke produced by cracking and coking vacuum residue of petroleum at 1500-1600℃ in a coking unit. It is generally believed to be an amorphous carbon body, or a highly aromatized high-molecular carbide containing tiny graphite crystals in the form of needles or granules.

[0031] Among them, the medium-sulfur coke is crushed by a jaw crusher, and the crushed medium-sulfur coke is pulverized and screened, and the pulverized particles of the medium-sulfur coke are 50um; the screening method is 200 mesh for screening the medium-sulfur coke.

[0032] Among them, the binder material in S3 is asphalt;

[0033] Asphalt is used to bind carbon aggregate and powder together and knead them to form a plastic paste. The binder asphalt has a lot of coke left after roasting and combines carbon aggregate and powder into a roasted electrode;

[0034] Different medium-sulfur cokes have great differences in composition. Medium-temperature and low-temperature medium-sulfur cokes contain high phenols. In terms of coal tar processing and utilization, except for some tar processing plants that specialize in processing low- and medium-temperature tars to produce products such as cresol, most tar processing plants only process high-temperature coal tar. High-temperature coal tar is mainly a complex mixture of aromatic hydrocarbons. Coal tar pitch for carbon industry is generally obtained by processing high-temperature coal tar, and the largest amount is binder pitch.

[0035] Wherein, asphalt material is added during the stirring process of the medium-sulfur coke powder, the ratio of the medium-sulfur coke powder to the asphalt material is 20:12, and after the addition is completed, the stirring speed is controlled at 2000 rpm for 1-2 hours;

[0036] Classification name Production process Material characteristics Performance requirements oil medium sulfur coke Delayed coking Low cost, good graphite performance, low thermal expansion coefficient Good conductivity, good thermal shock resistance, high strength coal Pitch coke Delayed coking Density is greater than medium sulfur coke Good electrical conductivity, radiation and oxidation resistance, high strength

[0037] It can be seen from the above that medium-sulfur coke has low cost, good graphite performance, and low thermal expansion coefficient, which is better than asphalt coke; high-quality medium-sulfur coke produced by delayed coking process is calcined in a rotary kiln, and the moisture and volatile matter are significantly reduced, making transportation and storage more convenient; in the graphitization process, graphitization temperature is a key factor that affects the graphitization degree of high-quality medium-sulfur coke;

[0038] Petroleum asphalt is divided into pure asphalt and blown asphalt. Pure asphalt is the residue after the liquid components are removed from crude oil by vacuum distillation; blown asphalt is a high-molecular substance formed by oxidation and polymerization of heavy crude oil after heating and blowing air into it. The latter is easier to form latex, and from the performance of the adhesive film, its heat resistance, weather resistance and impact resistance are better than pure asphalt.

[0039] Among them, in S4, the first heating rate is 20-30°C / min, the temperature is raised to 500°C, and maintained for 1 hour, and the second heating rate is 80-95°C / min, the temperature is raised to 1200°C, and maintained for 4-5 hours.

[0040] Among them, the negative electrode material is heated up and then dropped to 400-600°C for constant temperature maintenance for 5 hours.

[0041] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing single-granular negative electrode materials from medium-sulfur coke, characterized in that: The steps of producing single particle negative electrode material from medium sulfur coke are as follows: S1. Calcination: heating and calcining the medium-sulfur coke; S2. Crushing: The calcined medium-sulfur coke is cooled and crushed and sieved; S3, stirring and mixing: stirring and mixing the medium-sulfur coke powder and the binding material, and heating the mixture to obtain a negative electrode material; S4, heating: heating and cooling the negative electrode material; S5, graphite treatment: obtaining a single particle negative electrode material; The medium-sulfur coke is calcined at a temperature of 200°C / min, and the temperature is controlled at 1500°C-1600°C for 2 hours; The medium-sulfur coke is crushed by a jaw crusher, and the crushed medium-sulfur coke is crushed and sieved, and the crushed particles of the medium-sulfur coke are 50um; The temperature of the negative electrode material is then lowered to 400-600° C. for constant temperature maintenance for 5 hours.

2. The method for producing single-granular negative electrode materials from medium-sulfur coke according to claim 1, characterized in that: The binder material in S3 is asphalt.

3. The method for producing single-granular negative electrode materials from medium-sulfur coke according to claim 1, characterized in that: Asphalt material is added during the stirring process of the medium-sulfur coke powder, and the ratio of the medium-sulfur coke powder to the asphalt material is 20:

12. After the addition is completed, the stirring speed is controlled at 2000 rpm and the stirring is performed for 1-2 hours.

4. The method for producing single-granular negative electrode materials from medium-sulfur coke according to claim 1, characterized in that: In S4, the first heating rate is 20-30°C / min, the temperature is raised to 500°C, and maintained for 1 hour, and the second heating rate is 80-95°C / min, the temperature is raised to 1200°C, and maintained for 4-5 hours.

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