KR101357116B1 - Pitch manufactured from petroleum products and high yield method for manufacturing the same, and high performance carbon anode materials using the same - Google Patents

Abstract

The present invention relates to a method for producing a carbon anode material, the method comprising oxidizing a pitch and carbonizing the oxidized pitch under an inert gas. The method of making the pitch includes heat treating petrochemical by-products under high temperature and high pressure, and adding a high acidity catalyst material during the heat treatment.
The present invention differs from the conventional technology in that it adds a material for improving yield and performance in the middle of the high temperature and high pressure heat treatment, and the intermediate additive acts as a catalyst in the production of the pitch, and the yield is improved, and furthermore, the pitch is used. The battery efficiency and capacity of the battery thus produced are also improved.

Description

PITCH MANUFACTURED FROM PETROLEUM PRODUCTS AND HIGH YIELD METHOD FOR MANUFACTURING THE SAME, AND HIGH PERFORMANCE CARBON ANODE MATERIALS USING THE SAME}

The present invention relates to a method for producing a high performance carbon negative electrode material and a lithium secondary battery comprising a negative electrode material produced by the method.

Lithium secondary batteries with high energy density are currently being used as power supplies for mobile phones, laptops, hybrid cars, and the like.

In particular, the main components of these products include the anode, the cathode, the electrolyte, etc., the double cathode material generally occupies about 10% of the price composition, and currently commercially available cathode materials such as graphite-based negative electrode materials such as natural graphite, artificial graphite And low-temperature fired carbon such as soft carbon and hard carbon. In particular, the low-temperature treated carbon material (soft carbon) is an anode active material that is attracting attention as a negative electrode material applied to medium and large-sized batteries in which high output and low cost characteristics are more important than conventional hard carbon materials because of its low price, excellent charge and discharge speed, and excellent initial efficiency. to be.

Graphite carbon and hard carbon or soft carbon are mixed and used in the negative electrode material of currently commercially available medium and large lithium secondary batteries.

As such, the low-temperature fired anode carbon is usually made of pitch using petroleum-based and coal-based organic materials and carbonized after the pitch is manufactured, or carbonized to produce a cathode material, so that the price is relatively low, but the reversible capacity is 300 mAh /. It has the disadvantage of being smaller than g and having low yield in pitch production.

In order to solve this problem, composites such as Si, SiOx, Sn, SnOx, which are metals exhibiting high capacity after pitch production, are formed (Korean Patent No. 10-0646547), or graphite and the metal oxides are used together when pitch is manufactured. The method of manufacturing the pitch was put in (Korean Patent No. 10-1085048).

However, the negative electrode material manufactured using the pitch material manufactured through the patent invention has problems such as the price increase due to the administration of the composite, the cycle stability due to the metal and the metal oxide, and the productivity decrease due to the complicated manufacturing process. There is a problem of deterioration in safety during battery production.

Accordingly, the present inventors have diligently researched to overcome these problems, and have succeeded in developing a method of manufacturing a carbon anode material having high capacity, initial efficiency, and productivity while using petrochemical by-products. That is, an object of the present invention is to provide a high-performance low-temperature calcined carbon anode material, a method of manufacturing the same, and a lithium secondary battery using the same.

The present invention relates to a method for producing a pitch for a negative electrode material comprising the step of heat treating a petrochemical by-product under high temperature and high pressure and adding a high acidity catalyst material during the heat treatment.

The present invention also relates to a high performance carbon negative electrode material using a pitch produced by such a method and a method for producing the same.

The present invention also relates to a lithium secondary battery comprising a high performance carbon anode material produced by such a method.

Due to the manufacturing method of the present invention, the yield and productivity of the pitch are increased, and the capacity and efficiency of the negative electrode material and the secondary battery manufactured therefrom are also improved.

1 is an electron micrograph of a carbon material obtained through Example 2. FIG.
Figure 2 is a charge and discharge graph of the battery prepared in Example 6.
3 is a charge and discharge graph of the battery prepared in Comparative Example 2.
Figure 4 shows the results of performing Raman analysis on the carbon material obtained through Comparative Example 1 and Example 2.

The present invention relates to a method for producing a pitch for a negative electrode material comprising the step of heat treating a petrochemical by-product under high temperature and high pressure and adding a high acidity catalyst material during the heat treatment. By adding a high acidity catalyst material it is possible to improve the yield and performance during pitch heat treatment.

Petrochemical by-products are by-products from the process of producing petrochemicals. Specifically, by-products generated during terephthalic acid, phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, trimellitic acid, methacrylic acid or nitrotoluene Say Petrochemical by-products include, but are not limited to, compounds having a carbonyl group (C═O), compounds having a sulfuric acid group (-SOx) by sulfation, or compounds having a nitric acid group (-NOx) by nitrification, and the like. More specifically, the petrochemical by-products include benzoic acid, para-toluic acid, styrene oxide, 1,2-epoxy-phenoxypropane, glycidyl-2-methylphenyl ether, (2,3-epoxypropyl) benzene, 1- Phenylpropylene oxide, steelbene oxide, 2- (or 3- or 4-) halo (e.g. chloro, fluorine, bromo, or iodo) stilbene oxide, benzyl glycidyl ether, C1-10 straight chain Or branched chain alkyl (eg methyl, ethyl, propyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, etc.) phenyl glycidyl ether, 4-halo (eg chloro, fluoro Bromo, or iodo) phenyl glycidyl ether. In particular, in the present invention, pyrolysis fuel oil (PFO), heavy crude, extra heavy crude, vacuum residue, atmospheric residue, oil sand bitumen, or these 2 It may be a mixture of the above.

Unlike the conventional manufacturing method, the pitch is different from that of adding a high acidity catalyst material for improving yield and performance in the middle of high temperature and high pressure heat treatment.

Typically, the pitch is a process in which a low molecular weight material is converted into a high molecular weight material. To increase the speed of the process, catalysts such as HF, F ₂ , HBr, Br ₂ , and BF ₃ are used. These catalysts oxidize low-molecular-weight materials to form a reaction acid point to promote the polymerization reaction, but these catalysts are highly reactive and have toxic characteristics. According to the present invention, the polymerization reaction is initiated by adding and reacting a substance having various acidic points (high acidity) in the middle of the pitching reaction, or by administering and reacting a gas that promotes oxidation and dispersion. In the step it is added to promote this material to increase the yield and improve the productivity.

The pitch of the present invention includes the step of heat-treating the petrochemical by-products under high temperature and high pressure, the temperature of the heat treatment step is preferably 200 to 500 ℃, the pressure is preferably 2 to 50 atm.

Zeolite, silica, alumina, and the like are preferably added to the material in the middle of the pitch production, and the gas administered to promote oxidation and dispersion may be air, oxygen, nitrogen, carbon monoxide, steam, or the like. desirable.

The weight ratio of the petrochemical by-product of the material added in the middle of the pitch production is preferably 0.001 to 0.1. If the weight ratio is less than 0.001, there may be a problem that the content is so small that the effect on the change of properties is insignificant. If the weight ratio is more than 0.1, there may be a problem that serious disadvantages such as capacity decrease may occur due to the increased amount. have. The high acidity catalyst material is preferably added 1 hour to 5 hours after the heat treatment.

The gas to be administered to promote the oxidation and dispersion is preferably from 1 to 100 as a volume ratio to the total reactor size. If the volume ratio is less than 1, there may be a problem that the content is too small to have a small effect on the change of properties, and if the volume ratio exceeds 100, there may be a problem that serious disadvantages such as deterioration of pitch may be caused due to the increased amount. Can be.

The pitch produced through the manufacturing step of the pitch has a softening point of 70 to 300 ℃ and when heat-treated immediately there is a problem that the particles are formed into a single mass (monolith) through the molten state. Since the lithium secondary battery negative electrode material preferably has a particle size of several μm, the pitch prepared for this purpose is pulverized and then oxidized. Through this process, functional groups including oxygen are formed on the surface of the pitch, and the shape of the particles is maintained even when carbonized at a high temperature.

The present invention also relates to a method for producing a carbon negative electrode material comprising the step of oxidizing a pitch produced by the above method and carbonizing the oxidized pitch in an inert gas, and a high performance carbon negative electrode material produced therefrom.

After crushing or classifying the prepared pitch, the step of oxidizing may be oxidized while injecting oxygen or air at a temperature of 100 to 400 ° C. for 30 minutes to 5 hours after classifying and classifying the prepared pitch.

Carbonizing the oxidized pitch may be carbonized for 30 minutes to 10 hours at a temperature of 500 to 3000 ℃. In this carbonization process, the pitch components take the form of carbon to form a carbon anode material.

The carbon anode material prepared by the above step has a particle size of 0.1 to 200 ㎛, the surface area of 0.1 to 100 m ² / g, the Raman analysis results in the intensity ratio of D band and G band is 0.5 to 1.2, When applied, the charge and discharge capacity will be at least 400 mAh / g or more.

In addition, the present invention relates to a lithium secondary battery comprising a carbon anode material prepared through the above steps.

The carbon anode material prepared by the above step is mixed with polyvinylidene fluoride (PVDF) as a binder and carbon black as a conductive material, coated with an aluminum current collector, and then dried and roll pressed to prepare an electrode. It can be used for the lithium secondary battery.

Hereinafter, the present invention will be described in more detail with reference to Preparation Examples and Examples, but the following Preparation Examples and Examples are only intended to illustrate the present invention and should not be construed as limiting the present invention.

compare Manufacturing example  One : Pitch  Produce

PFO (Il Industry) containing about 20% by weight of naphthalene was heat-treated at a temperature of 350 ° C. and 7 atmospheres of pressure to prepare a pitch.

Manufacturing example  1: zeolite addition Pitch  Produce

500 g of PFO (Il Industry) containing about 10% by weight of naphthalene was heat-treated at a temperature of 300 ° C. and a pressure of 5 atm, and 2 hours after the start of the heat treatment, 1 g of zeolite ZSM5 was added thereto, followed by sufficient mixing, followed by reaction. .

Manufacturing example  2: alumina addition Pitch  Produce

500 g of PFO (Il Industry) containing about 10% by weight of naphthalene was heat-treated at a temperature of 300 ° C. and a pressure of 5 atm, and 2 hours after the start of the heat treatment, 1 g of alumina material was added thereto, sufficiently mixed, and reacted to prepare a pitch.

Manufacturing example  3: oxygen administration Pitch  Produce

PFO (Il Industry) 500 g was heat-treated at a temperature of 300 ° C. and a pressure of 5 atm, and 1 hour after the start of the heat treatment, oxygen was administered for 10 minutes, followed by reaction.

Manufacturing example  4: nitrogen administration Pitch  Produce

500 g of PFO (Il Industry) was heat-treated at a temperature of 300 ° C. and a pressure of 5 atm, and 1 hour after the start of the heat treatment, nitrogen was administered for 10 minutes, followed by reaction.

The yields of the pitches prepared in Comparative Preparation Example 1 and Preparation Examples 1 to 4 are shown in Table 1.

Addition / dosage material during heat treatment Pitch Yield (%) Comparative Production Example 1 none 25 Production Example 1 Zeolite 28 Production Example 2 Alumina 27 Production Example 3 Oxygen 28 Production Example 4 nitrogen 30

Comparative Example  1: Preparation of Carbon Cathode Materials

The pitch prepared by the method of Comparative Preparation Example 1 was oxidized at 250 ° C. under air, and carbonized under nitrogen gas at 700 ° C. for 1 hour to prepare a carbon anode material.

Example  1: Preparation of Carbon Cathode Materials

The pitch prepared by the method of Preparation Example 1 was oxidized at 250 ° C. under air, and carbonized under nitrogen gas at 1000 ° C. for 1 hour to prepare a carbon anode material.

Example  2 to 4: Preparation of Carbon Cathode Materials

In the same manner as in Example 1, the pitch prepared by the method of Preparation Examples 2 to 4 was respectively oxidized and carbonized to prepare a carbon anode material. An electron micrograph of the carbon material obtained through Example 2 is shown in FIG. 1.

Comparative Example  2: manufacture of lithium secondary battery

A carbon anode material prepared by the method of Comparative Example 1, a polyvinylidene fluoride (PVDF), a binder, and carbon black (commercial name: super p), a conductive material, were mixed in a ratio of 90: 5: 5, and the aluminum was mixed. After coating with a current collector, it was dried and roll pressed (roll press) to produce a coin cell using an electrode prepared. The electrolyte used here was 1M LiPF ₆ EC / DMC. A charge and discharge graph of the manufactured battery is shown in FIG. 3. That is, FIG. 3 is a result of evaluating the characteristics of the lithium secondary battery negative electrode material by using a carbon material obtained through Comparative Example 1, and manufacturing a coin cell in Comparative Example 2. Referring to Figure 3 it can be seen that the initial efficiency is 50%, the initial discharge capacity is as small as 250 mAh / g.

Example  5: manufacturing of a lithium secondary battery

The carbon negative electrode material prepared by the method of Example 1, polyvinylidene fluoride (PVDF), a binder, and carbon black (commercial name: super p), a conductive material, were mixed in a ratio of 90: 5: 5 to aluminum. After coating with a current collector, it was dried and roll pressed (roll press) to produce a coin cell using an electrode prepared. The electrolyte used here was 1M LiPF ₆ EC / DMC.

Example  6 to 8: manufacture of a lithium secondary battery

Coin cells were prepared using the carbon anode materials prepared in the methods of Examples 2 to 4 in the same manner as in Example 5. A charge and discharge graph of the battery prepared in Example 6 is shown in FIG. 2. That is, Figure 2 is a result of evaluating the characteristics of the lithium secondary battery negative electrode material by using a carbon negative electrode material obtained in Example 2, by manufacturing a coin cell in Example 6. Referring to FIG. 2, it can be seen that the initial efficiency is 69% and the initial discharge capacity is about 479 mAh / g. This means that a very high reversible capacity was expressed even though no substance such as silicon was contained at all.

Initial efficiency and reversible capacity of the batteries prepared in Comparative Example 2 and Examples 5 to 8 are shown in Table 2.

Addition / dosage material during heat treatment Initial Efficiency (%) Reversible Capacity (mAh / g) Comparative Example 2 none 50 250 Example 5 Zeolite 65 450 Example 6 Alumina 69 479 Example 7 Oxygen 67 465 Example 8 nitrogen 65 462

Example  9: Raman analysis

Raman analysis was performed on the carbon materials obtained through Comparative Example 1 and Example 2. The Raman analyzer used here analyzes the carbon produced using Bruker's 20 mW 532 nm line laser. 4 shows the results. The peak observed at 1580 cm ^-1 is due to the G band, E2g symmetry, which is attributed to the crystalline graphite structure, and the peak observed at 1360 cm ^-1 is due to the D band, A1g symmetry, which is due to the low crystalline structure. The ratio value of peak intensity at each peak) is an important factor in determining the crystallinity of carbon. For Comparative Example 1 and Example 2 it can be seen that the ratio of the peak intensity is 1.4 and 1.0, respectively, that the carbon produced through Example 2 has a lower ratio, which means that it has a high crystallinity.

Claims (13)

Heat-treating the petrochemical by-products at a temperature of 200 to 500 ° C. and a pressure of 2 to 50 atmospheres; And
Adding and mixing a high acidity catalyst material during the heat treatment and after 1-4 hours from the start of the heat treatment
A method of manufacturing a pitch for a negative electrode material, including. The method of claim 1, wherein the petrochemical by-products are pyrolysis fuel oil (PFO), heavy crude, extra heavy crude, vacuum residue, atmospheric residue oil, oil sand Vitoman, or a mixture of two or more thereof. 2. The method of claim 1 wherein the high acidity catalyst material is zeolite, silica or alumina. The method of claim 1, further comprising administering a gas. The method of producing a pitch according to claim 4, wherein the gas is air, oxygen, nitrogen, carbon monoxide or steam. The method of claim 1, wherein the weight ratio of the high acidity catalyst material to be added is 0.001 to 0.1 relative to the petrochemical by-products. The method of claim 4, wherein the volume ratio of the gas to be administered is 1 to 100 relative to the total reactor. Oxidizing the pitch produced by the method of claim 1; And
Carbonizing the oxidized pitch under inert gas
Method for producing a carbon negative electrode material comprising a. The method of producing a carbon negative electrode material according to claim 8, wherein the oxidizing step is pulverized or classified and then oxidized. 10. The method of claim 8, wherein the carbonizing step carbonizes at a temperature of 500 to 3000 [deg.] C. for 30 minutes to 10 hours. A carbon negative electrode material produced by the method of claim 8, characterized in that the particle size is 0.1 to 200 μm and the surface area is 0.1 to 100 m ² / g. The carbon negative electrode material produced by the method of claim 8, wherein the ratio (D / IG) of the D band intensity and the G band intensity is 0.5 to 1.2 as a result of the Raman analysis. A lithium secondary battery comprising a carbon anode material produced by the method of claim 8.

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