KR100732458B1 - A fabrication method of carbonaceous anodic materials - Google Patents

Abstract

The present invention relates to a method for producing a carbonaceous electrode material, and an object thereof is to provide a method for producing a spherical carbonaceous electrode material having a uniform particle size distribution and a high packing density at low cost in high yield. To this end, in the present invention, the mixture of the graphite powder and the solid-state thermosetting resin powder or the solid-state pitch powder is put into a surface grinder capable of rotating at high speed, and then rotated to generate spherical particles, and the spherical particles are separated from the mixture. And sequentially firing the separated spherical particles to prepare a spherical carbonaceous electrode material.

Electrode material, graphite powder, thermosetting resin powder, pitch powder,

Description

A fabrication method of carbonaceous anodic materials

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a carbonaceous electrode material, and more particularly, an electrode material of a lithium ion battery (LIB), and a double layer capacitor (DLC). It is related with the method of manufacturing spherical carbonaceous electrode material used as electrode material of DLC) at low cost, and with high yield.

In general, materials used as electrode materials for LIB and DLC include natural graphite powder and synthetic spherical particles, called MCMB (Meso Carbon Micro Beads, hereinafter referred to as MCMB), or modified materials thereof. Fine fiber powder, high temperature treatment of acicular coke, etc. may be used.

However, these materials have a limitation in that charge / discharge capacities of 350 mAh / g or more cannot be obtained, and thus, various modifications have recently been made to increase the charge / discharge capacities.

In particular, the electrode material has a very important factor in filling density during electrode production. Therefore, the uniformity of particle size distribution is recognized as a very important management factor. Since a large amount of fine powder of 5 μm or less is generated, the production yield is lowered and the filling density during electrode manufacturing is reduced. There is a problem such as a rise in manufacturing price.

In addition, carbon materials used as electrode materials for LIB, Lithium polymer Battery (LPB) and Electric Double Layer Capacitor (EDLC) have a constant particle size distribution and contain 50% or more of carbon elements. It must be chemically stable. In other words, the chemical instability of the carbonaceous electrode material directly affects the characteristics of the product when used as an electrode material of the battery, and thus it is impossible to maintain the stable quality of the product. Should be low.

In addition, as for the carbonaceous electrode material, the physical properties such as particle size distribution, packing density, crystallinity, and surface properties of the carbonaceous electrode material are important factors, and these physical properties vary depending on the raw material and manufacturing conditions of the electrode material.

In general, the carbonaceous electrode material has a smaller and more uniform particle size. However, when the carbonaceous electrode material is too small or too large, the carbonaceous electrode material is not suitable because the characteristics of the electrode material deteriorate.

Currently known methods for producing carbonaceous electrode materials include: purifying raw material pitch, heat treatment in an inert atmosphere to form globules, and then performing solvent extraction using heavy oil (Japanese Patent 7-145387), raw material After the pitch is reacted by blowing air at low temperature in one step, heat treatment is carried out in an inert atmosphere in two steps to form globules, which are extracted and separated using a solvent (Japanese Patent 93-234584). After dissolving in, in one step, a strong stirring is performed in the reaction system in which the surfactant is present, the solution is added to prepare an emulsion solution, and in the second step, the method is separated by using a spray dryer (Korean Patent No. 56299), aggregate Anisotropic mesophase pitch in the state is melted by heating using an isotropic pitch as a dispersion medium, and then liquid crystallization is induced by using the difference in the interfacial tension between the two materials. Method (Korean Patent 97-42167), the heat treatment obtained by heat treatment by adding a zirconium compound or a boron compound in the process of the second heat treatment of the isotropic pitch and the thermosetting resin mixture at low temperature to produce a predetermined particle size by grinding Method (Korean Patent 98-56679), thermosetting resin or a mixture with coal tar and the method of pulverizing and carbonized to produce carbon particles (Korean Patent 98-54700) and the like.

However, the above methods can produce a spherical body of a certain standard, but there is a problem that can not suppress the generation of fine particles of less than 5 ㎛ occurring during the normal grinding process, the fracture surface of the particles are present at an acute angle There is a problem that the filling density is lowered.

The present invention has been proposed to solve the above problems, and an object thereof is to provide a method for producing a spherical carbonaceous electrode material having a uniform particle size distribution and a high packing density at a high yield at a low cost.

In order to achieve the above object, in the present invention, a mixture of graphite powder, a solid thermosetting resin powder or a solid pitch powder is introduced into a surface grinder capable of rotating at high speed, and then rotated to generate spherical particles. A spherical carbonaceous electrode material is prepared by sequentially separating the particles from the mixture and firing the separated spherical particles.

At this time, it is preferable to mix the solid-state thermosetting resin powder or the solid-state pitch powder in 60 weight% or less with respect to the whole mixture.

In addition, when rotating in the surface polishing machine, it is preferable to rotate at a speed of 10,000 rpm or more.

When baking, it is preferable to set it as the temperature of 800 degreeC-1,200 degreeC.

Hereinafter, the carbonaceous electrode material manufacturing method according to the present invention will be described in detail.

Thermosetting resins and pitch low-temperature sintered materials are used to replace materials used as electrode materials for conventional LIBs and DLCs. Despite their low efficiency, these materials have the potential to replace natural graphite or MCMB due to their high charge and discharge characteristics. It is attracting attention as a material that is present, and research on the development of many plastic products using them as a raw material has been conducted.

Thermosetting resin refers to a type of resin which is gradually solidified after melting by heating. Thermosetting resin is present in liquid and solid phase at room temperature, and the liquid resin is cured and cured gradually by heating. The solid resin is characterized by being melted once by heating and then cured.                     

Meanwhile, heavy oil is a generic term for coal tar, which is a viscous black liquid substance generated during coal distillation, and residue oil generated during refinery. The heavy oil is a black soft pitch through a predetermined heat treatment process. Or to form a hard pitch material. Heavy oils have a unique odor, and coal tar is generally more aromatic than petroleum refining oil and has a high carbon yield. These heavy streams exist in liquid phase at room temperature, and by distilling them, a solid phase pitch is obtained as the final company.

This solid phase pitch represents thermoplastic, and when subjected to heat treatment at a constant temperature for a certain time, the solid phase is completely converted into a solid phase, thereby converting it into an insoluble material. Pitches represent an anisotropic liquid crystal state which is an intermediate phase in the process of being converted into a solid phase, and are used as a carbonaceous electrode material for batteries by separating such liquid crystals using a solvent.

In the present invention, in order to produce electrode materials for LIB, LPB and EDLC, first, a solid graphite powder having a particle size of 5 μm or less and a solid thermosetting resin powder or a solid pitch powder are mixed to prepare a mixture.

In this case, as graphite powder, natural graphite or artificial graphite powder may be used. Since the production yield of the spherical particles is proportional to the input amount of the solid phase thermosetting resin powder or the solid phase pitch powder, which is low specific gravity powder, the higher the dosage of the low specific gravity powder in order to increase the production efficiency, the more advantageous the spheroidization efficiency at 60 wt% It is preferable to mix so that the content of the low specific gravity powder in the mixture will be 60% or less.                     

Next, the mixture is introduced into a high-speed granulator capable of high speed rotation and rotated at a speed of 15,000 rpm or more to form spherical particles through a spheroidization treatment to induce surface spheroidization through friction between powders.

As the granulator for spheroidizing the mixture, any one can be used as long as it can rotate at a high speed and have a polishing function of the surface portion rather than crushing the particles, but it is preferable to use a surface polishing machine having a rotation speed of 10,000 rpm or more.

The crushed powder not only has a low filling density but also a relatively high specific surface area, which increases the amount of binder and electrolyte used in electrode production, as well as decreases the charge / discharge characteristics per unit weight. In the case of producing spherical particles, there is an advantage that the electrode material having excellent performance can be manufactured in high yield.

Next, a spherical particle having a desired particle size, for example, 10 µm or more is separated from the mixture in which the spheroidization treatment is completed, and then the separated spherical particles are fired at a predetermined temperature for a predetermined time.

Separation of spherical particles can be carried out using a common specific gravity separation method. It bakes at the temperature of 800 degreeC-1,200 degreeC.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

Examples 1-5

In Examples 1 to 5, the natural graphite powder and the solid thermosetting resin powder or the solid pitch powder, which are low specific gravity powders, were mixed under the conditions shown in Table 1 below, and then charged into a high-speed surface polishing machine equipped with an agitator, and the raw materials were sufficiently mixed. Spherical particles were prepared by rotating at a speed of 15,000 rpm for 30 minutes to be assembled. At this time, since the internal temperature of the surface polisher may be increased, the internal temperature of the surface polisher was maintained below 100 ° C. through cooling, and the target was prepared by separating particles using specific gravity separation. The resulting spherical particle generation rate is shown in Table 1 below.

division Raw material (wt%) Treatment condition (rpm- ℃ -min.) Spherical Particle Formation (wt%) Low specific gravity powder Graphite Powder Revolutions Internal temperature time Example 1 60 (resin powder) 40 15,000 100 30 70 Example 2 50 (resin powder) 50 15,000 100 30 80 Example 3 60 (pitch powder) 40 15,000 100 30 85 Example 4 50 (pitch powder) 50 15,000 100 30 88 Example 5 40 (pitch powder) 60 15,000 100 30 90

As shown in Table 1, when the carbonaceous electrode material was prepared according to Examples 1 to 5 of the present invention, the spherical particle generation rate was very high as 70 wt% or more, and the pitch powder was used as the low specific gravity powder. Compared with the case of using the powder was confirmed to show a higher production rate.

Comparative Examples 1 to 3

In Comparative Examples 1 to 3, 70% by weight or 80% by weight of the solid-state thermosetting resin powder, which is a low specific gravity powder, was mixed with graphite powder, and then charged into a high-speed surface polishing machine equipped with an agitator, and the raw materials were sufficiently mixed. The spherical particles were prepared by rotating at a speed of 15,000 rpm or 5000 rpm for 30 minutes to be assembled. At this time, since the internal temperature of the surface polishing machine may be increased, the temperature inside the surface polishing machine was maintained below 100 ° C. through cooling, etc., and the target product was prepared by separating particles using specific gravity separation. The resulting spherical particle generation rate is shown in Table 2 below.

division Raw material (wt%) Treatment condition (rpm- ℃ -min.) Spherical Particle Formation (wt%) Low specific gravity powder Graphite powder Revolutions Internal temperature time Comparative Example 1 70 (resin powder) 30 15,000 100 30 40 Comparative Example 2 80 (resin powder) 20 15,000 100 30 33 Comparative Example 3 70 (resin powder) 30 5,000 100 30 17

As shown in Table 2, in Comparative Examples 1 to 3 having a resin content of 70% by weight or more, the spheroidization was not sufficiently achieved, resulting in low spheroidal particle generation. The production rate was 17% lower.

As described above, when the carbonaceous electrode material is manufactured according to the present invention, there is an effect of producing a spherical carbonaceous electrode material having a uniform particle size distribution and a high packing density at low cost with high yield.

In addition, there is an effect that can adjust the production rate of the spherical particles according to the type of material, the mixing ratio and the number of revolutions.

Claims (4)

Injecting a mixture of the graphite powder, the solid state thermosetting resin powder, or the solid state pitch powder into a surface grinder capable of rotating at high speed, thereby rotating, thereby producing spherical particles; Separating the spherical particles from the mixture; Carbonaceous electrode material manufacturing method comprising the step of firing the separated spherical particles. The method of claim 1, A method of producing a carbonaceous electrode material, characterized in that the solid phase thermosetting resin powder or the solid phase pitch powder is mixed at 60 wt% or less with respect to the whole mixture. The method of claim 2, The rotation is a carbonaceous electrode material manufacturing method characterized in that performed at a speed of 10,000 rpm or more. The method according to any one of claims 1 to 3, The firing is a carbonaceous electrode material manufacturing method, characterized in that carried out at a temperature of 800 ℃ to 1,200 ℃.