JP2000340232A - Carbon material for electrode and nonaqueous secondary battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon material for an electrode having a high electrode filling property, high energy density, and an excellent quick charging/discharging property. SOLUTION: In this carbon material for an electrode, a surface interval (d002) by a wide angle X-ray diffraction method (002) is less than 0.337 nm, the crystallite size (Lc) is 90 nm or larger, R value which is the ratio of the peal intensity of 1360 cm-1 versus the peak intensity at 1580 cm-1 is 0.2 or more, and a tap density is 0.75 g/cm3 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a carbon material for an electrode and a non-aqueous secondary battery using the same. More specifically,
The present invention relates to a carbon material for an electrode, preferably a carbon material for a negative electrode, which can constitute a nonaqueous secondary battery having high capacity and good rapid charge / discharge properties.

[0002]

2. Description of the Related Art In recent years, secondary batteries of high capacity have been required as electronic devices have become smaller. In particular, lithium secondary batteries, which have a higher energy density than nickel-cadmium batteries and nickel-metal hydride batteries, have attracted attention. Attempts were initially made to use lithium metal as the negative electrode material, but during repeated charging and discharging, lithium was precipitated in a resinous (dendrite) form, penetrated through the separator, reached the positive electrode, and short-circuited both electrodes. Turns out to be dangerous. Therefore, attention has been paid to a carbon-based material that can prevent the generation of dendrite in place of the metal electrode.

As a non-aqueous electrolyte secondary battery using a carbon-based material, a battery using a non-graphitizable carbon material having low crystallinity as a negative electrode material has been put on the market. Subsequently, batteries using graphites having a high degree of crystallinity were put on the market, and have reached the present. The electrical capacity of graphite is 372 mAh / g, which is theoretically the maximum, and a battery having a high charge / discharge capacity can be obtained by appropriately selecting an electrolytic solution. Further, Japanese Unexamined Patent Publication No.
The use of a carbonaceous material having a multilayer structure as disclosed in JP-A-77-77 is also being studied. This is because of the advantages of graphite with high crystallinity (high capacity and small irreversible capacity) and disadvantages (decomposes propylene carbonate-based electrolyte) and the advantage of low crystallinity carbonaceous material (excellent stability with electrolyte). ) And disadvantages (large irreversible capacity) are combined to take advantage of each other's advantages and compensate for the disadvantages.

[0004] Graphites (graphite and multilayer carbonaceous materials containing graphite) have higher crystallinity and higher true density than non-graphitizable carbon materials. Therefore, when a negative electrode is formed using these graphite carbon materials, high electrode filling properties can be obtained, and the volume energy density of the battery can be increased. When a negative electrode is composed of a graphite-based powder, a method of mixing a powder and a binder, preparing a slurry containing a dispersion medium, applying this to a metal foil as a current collector, and then drying the dispersion medium is generally used. It is used regularly. At this time, it is general to provide a step of further performing compression molding for the purpose of pressing the powder to the current collector, making the electrode plate thickness uniform, and improving the electrode plate capacity. By this compression step, the electrode density of the negative electrode is improved, and the energy density per volume of the battery is further improved.

[0005] However, general graphite materials that are highly crystalline and commercially available have a particle shape of flakes, scales, and plates. This particle shape is scaly, scaly,
The plate shape is considered to be derived from the fact that the carbon crystal network plane grows in one direction to form graphite crystalline graphite. When these graphite materials are used for a negative electrode of a non-aqueous electrolyte secondary battery, the irreversible capacity is small due to the high crystallinity, and a large discharge capacity is exhibited.
The plate-like shape has a small amount of crystal edge planes through which lithium ions can enter and exit, and a large amount of basal planes that do not participate in lithium ion entry and exit.As a result, the capacity decreases during rapid charge and discharge at high current density. Can be seen. Also,
When the graphite particles are made into an electrode through the above-mentioned electrode manufacturing process,
Although the electrode plate density increases according to the degree of compression, on the other hand, since the particle gap is not sufficiently ensured, there is a problem that the movement of lithium ions is hindered and the rapid charge / discharge performance of the battery is reduced.

Further, when the plate-like graphite particles are formed as electrodes, the plate surface of the powder has a high probability of being parallel to the electrode plate surface due to the effects of the slurry application step and the electrode plate compression step. Are arranged. Therefore, the edge surfaces of the graphite crystallites constituting the individual powder particles are formed with a relatively high probability in a positional relationship perpendicular to the electrode surfaces. When charging / discharging is performed in such an electrode plate state, lithium ions that move between the positive and negative electrodes and are inserted and desorbed into graphite need to once go around the powder surface, and the ion transfer efficiency in the electrolyte solution There was also a problem that it was extremely disadvantageous in that respect. Further, there is a problem that the voids left in the electrode after molding are closed to the outside of the electrode because the particles have a plate-like shape. That is, since free flow of the electrolyte solution outside the electrode is hindered, there is a problem that movement of lithium ions is hindered.

On the other hand, graphite of mesocarbon microbeads is used as a negative electrode material having a high ratio of crystal edge planes into and out of which lithium ions enter and having a spherical shape capable of securing voids necessary for lithium ion movement in the electrode plate. Has been proposed and already commercialized. If the ratio of the edge surface is high, the area where lithium ions can enter and exit the particles increases,
In addition, if the form is spherical, even after the above-described electrode plate compression step, the individual powder particles do not have a selective arrangement, the isotropic orientation of the edge surface is maintained, and the ion Is maintained at a good speed. Furthermore, since the voids remaining inside the electrode are connected to the outside of the electrode due to their particle shape, the movement of lithium ions is relatively free, and the electrode structure is capable of responding to rapid charging and discharging. . However, since the mesocarbon microbeads have a low crystal structure level as graphite, the electric capacity limit is 300.
It is already widely known that it is as low as mAh / g and is inferior to scaly, scaly or plate-like graphite.

In view of these problems, inventions have been made in which the shape of graphite used in non-aqueous electrolyte secondary batteries is specified. For example, Japanese Patent Application Laid-Open No. 8-180873 discloses an invention in which the ratio of flaky particles to relatively non-flaky particles is specified. On the other hand, JP-A-8-836
No. 10 describes that, on the contrary, scaly particles are preferable.

[0009]

There is a need for an electrode having both high electric capacity and excellent rapid charge / discharge properties for a practical battery. However, an electrode that sufficiently satisfies such requirements has not yet been provided. For this reason,
In particular, it is strongly desired to improve the rapid charge / discharge properties of flaky, scaly, and plate-like graphitic materials. Therefore, the present invention has been made to solve the problems of the conventional technology in response to such a conventional demand. That is, an object of the present invention is to provide a carbon material for an electrode having a high electrode filling property, a high energy density, and an excellent rapid charge / discharge property.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, in order to improve the performance of the electrode, the inside of the graphite particles must be highly crystalline. Maintain a high discharge capacity, the thickness direction of the plate-like graphite particles is relatively thick, and the part close to the particle surface, especially the basal surface is rough (the cracks and bends on the basal surface cause The use of graphite particles, which have a high percentage of edges due to the presence of particles with exposed edges, increases the amount of lithium ions that can enter and exit, and the shape of the graphite particles is more nearly spherical, making it more compact. By using a carbon material with a high carbon content, the isotropic arrangement of the particles, that is, the isotropic arrangement of the edge portion is enhanced, so that it is possible to obtain an electrode having high capacity rapid charge / discharge characteristics and excellent cycle characteristics. To get Was Tsu.

The carbon material for an electrode according to the present invention has been completed on the basis of such findings, and firstly, the (002) plane spacing (d002) is 0.1 mm by wide-angle X-ray diffraction.
Less than 337 nm, the crystallite size (Lc) is more than 90 nm, R value is the peak intensity ratio of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectrum is 0.20 or more and a tap density of 0.75g / Cm ³ or more, and secondly, the present invention provides a method of mixing a carbon material having the above characteristics with an organic compound as a carbon material for an electrode, and then carbonizing the organic compound. Third, a negative electrode containing a carbonaceous material capable of occluding and releasing lithium, a positive electrode, and a solute and an organic solvent. In a non-aqueous electrolyte secondary battery having a non-aqueous electrolyte, at least a part of the carbonaceous material has a carbonaceous material or a multilayer structure having the above characteristics. A nonaqueous secondary battery, which is a quality material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a carbon material for an electrode, a multi-layered carbon material for an electrode and a secondary battery of the present invention will be described in detail.

Carbon Material for Electrode The carbon material for electrode of the present invention is obtained by a wide-angle X-ray diffraction method.
02) plane spacing (d002) and crystallite size (L
c) and 1360 c for a peak intensity of 1580 cm ⁻¹ in the argon ion laser Raman spectrum
The R value, which is the peak intensity ratio of m- ¹ , and the tap density are within predetermined ranges. That is, the carbon material for an electrode of the present invention has a (002) plane spacing (d002) of less than 0.337 nm and a crystallite size (Lc) of 90 nm or more, as determined by the wide-angle X-ray diffraction method. The electrode carbon material for the invention, R value is the peak intensity ratio of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectrum is 0.20
Or more, preferably 0.23 or more, particularly preferably 0.2
Five or more can be selected and used. The upper limit of the R value may be 0.9 or less, preferably 0.7 or less, and particularly preferably 0.5 or less. Further, the carbon material for an electrode of the present invention is characterized in that the tap density is 0.75 g / cm ³ or more, preferably 0.80 g / cm ³ or more, and the upper limit is preferably 1.40 g / cm ^{3. 3} or less, more preferably 1.20 g / cm ³ .

The plane spacing (d002) of the (002) plane and the crystallite size (Lc) determined by the wide-angle X-ray diffraction method are values representing the crystallinity of the bulk carbon material, and the plane spacing (d002) of the (002) plane. Is smaller, and the larger the crystallite size (Lc), the higher the crystallinity of the carbon material. Further, the index in the present invention, R value is the peak intensity ratio of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectrum representing the crystallinity in the vicinity of the surface of the carbon particles (from the particle surface to 100Å position) The larger the R value, the lower the crystallinity or the more disordered the crystal state.

That is, in the present invention, the plane spacing (d002) of the (002) plane by the wide-angle X-ray diffraction method is 0.337.
nm, crystallite size (Lc) is 90 nm or more, and 1360 cm with respect to a peak intensity of 1580 cm ^-1 in an argon ion laser Raman spectrum.
^The carbon material for an electrode having an R value of 0.20 or more, which is a peak intensity ratio of ⁻¹ , has a high crystallinity of carbon particles, but the vicinity of the surface of the particles is rough and has a large amount of distortion, that is, the abundance of edge portions. Is higher. Further, a carbon material for an electrode having a tap density of 0.75 g / cm ³ or more indicates that the filling rate of the electrode is high and the particle shape is round.

In this specification, "tap density" is 1
It means the bulk density after tapping 000 times and is represented by the following equation.

## EQU1 ## Tap density = mass of powder filling / packing volume of powder

The filling structure of the powder particles depends on the size and shape of the particles, the degree of interaction between the particles, and the like.
In this specification, the tap density is used as an index for quantitatively discussing the filling structure. Various expressions have been proposed as expressions representing tap filling behavior. As an example, the following equation:

Ρ−ρ _n = A · exp (−k · n) Here, ρ is the bulk density at the end of filling, ρ _n is the bulk density at the time of filling n times, and k and A are constants. "Tap density" as used herein is 20 c
The bulk density of the 1000 taps filling of the m ³ cell (ρ
₁₀₀₀ ) as the final bulk density ρ.

Other physical properties of the carbon material for an electrode of the present invention are not particularly limited as long as these conditions are satisfied. However, preferable ranges of other physical properties are as follows. The carbon material for an electrode of the present invention has an average particle size of 2 to 2.
It is preferably in the range of 50 μm, more preferably in the range of 4-35 μm, more preferably in the range of 5-27 μm, and even more preferably in the range of 7-19 μm. In addition, in this specification, the range described by "-" shows the range including the numerical value described before and after "-".

The electrode carbon material of the present invention, the BET specific surface area is less than 18m ² / g, still more 15 m ² / g or less, and particularly preferably not more than 13m ² / g. In addition, 1580c in the argon ion laser Raman spectrum
The half-value width of the peak at m ^-1 is preferably 20 cm ^-1 or more, and the upper limit is preferably 27 cm ^-1 or less,
21 to 26 cm ^-1 can be particularly selected and used.
Further, the carbon material for an electrode of the present invention has a true density of 2.21 g.
/ Cm ³ or more, preferably 2.22 g / cm ³
More preferably, it is particularly 2.24 g / cm.
It is preferably ³ or more.

The carbon material for an electrode according to the present invention is a flow type capable of photographing thousands of particles dispersed in a liquid one by one using a CCD camera and calculating an average shape parameter thereof. In a particle image analyzer, the average circularity for all particles (the ratio of the perimeter of the circle corresponding to the particle area as the numerator and the perimeter of the imaged particle projection image as the denominator, the particle image is close to a perfect circle (The smaller the particle image becomes, the smaller the particle image becomes elongated or irregularly shaped) becomes 0.940 or more. Further, the carbon material for an electrode of the present invention has an 136 nm in the argon laser Raman spectrum.
The peak area near 0 cm ^-1 (1260-1460 cm
G value is the area ratio of the peak area in the vicinity of 1580 cm ^-1 (integrated value of 1480～1680Cm ^-1) to the integral value) of ^-1, preferably less than 3.0, more preferably 2.
It is less than 5, and the lower limit is not particularly limited, but is preferably 1.0 or more.

As the carbon material for an electrode of the present invention, a naturally occurring carbon material or an artificially produced carbon material may be used. Further, the method for producing the carbon material for an electrode of the present invention is not particularly limited. Therefore, it is also possible to select and obtain a carbon material for an electrode having the above characteristics by using a separation means such as sieving or air classification. The most preferable production method is a method for producing a carbon material for an electrode by modifying a naturally produced carbon material or an artificially produced carbon material by applying a mechanical energy treatment. Therefore, the mechanical energy processing will be described below.

The carbon material as a raw material to be subjected to the mechanical energy treatment is a natural or artificial graphite powder or a carbon powder which is a graphite precursor. These graphite powders and carbonaceous powders have a plane spacing (d002) of 0.340 nm.
And a crystallite size (Lc) of 30 nm or more and a true density of 2.25 g / cm ³ or more are preferable. Among them, those having a plane spacing (d002) of less than 0.338 nm are more preferable, and those having a plane spacing (d002) of less than 0.337 nm are still more preferable. Further, the crystallite size (Lc) is more preferably 90 nm or more, and further preferably 100 nm or more. The average particle size is preferably at least 10 μm, more preferably at least 15 μm,
Those having a size of 20 μm or more are still more preferable, and those having a size of 25 μm or more are still more preferable. The upper limit of the average particle size is preferably 1 mm or less,
m or less, more preferably 250 μm or less, and even more preferably 200 μm or less.

The graphite powder and the carbon powder can be used as raw materials regardless of whether they have high or low crystallinity. Raw materials having low crystallinity have relatively low plane orientation and are disordered in the structure. Therefore, it is easy to obtain a processed material having a relatively isotropic and rounded crushed surface by performing mechanical energy treatment. Further, the crystallinity can be increased by further performing a heat treatment after the mechanical energy treatment.

Among the carbon materials to be subjected to the mechanical energy treatment, highly-oriented graphite in which hexagonal mesh planes are largely grown in a plane orientation as highly crystalline carbon materials having a developed carbon hexagonal mesh plane structure; Examples include isotropic high-density graphite in which highly oriented graphite particles are aggregated in the same direction. As highly oriented graphite, natural graphite from Sri Lanka or Madagascar, so-called quiche graphite precipitated as supersaturated carbon from molten iron, and artificial graphite with a high degree of graphitization can be exemplified as suitable ones. .

Natural graphite is classified into flaky graphite (Flake Glaphite) and scaly graphite (Crystalline (Vein) G) depending on its properties.
laphite) and soil graphite (Amorphousu Glaphite) (graphites in the “Granular Process Technology Integration” (published in 1973 by the Industrial Technology Center) and “HANDBOOK”.
OF CARBON, GRAPHITE, DIAMOND AND FULLERENES "(Noye
s Publications)). The degree of graphitization is highest for scaly graphite at 100%, followed by scaly graphite at 99%.
Although 9% is high, soil graphite is low at 28%. Flake graphite, a natural graphite, is produced in Madagascar, China, Brazil, Ukraine, Canada, etc., and flaky graphite is mainly produced in Sri Lanka. Soil graphite is mainly produced in the Korean Peninsula, China, Mexico, etc. Among these natural graphites, soil graphite generally has a small particle size and low purity. On the other hand, flaky graphite and flaky graphite have advantages such as a low degree of graphitization and a low amount of impurities, and therefore can be preferably used in the present invention.

Artificial graphite is prepared by mixing petroleum coke or coal pitch coke in a non-oxidizing atmosphere at 1500 to 30%.
It can be produced by heating at a temperature of 00 ° C. or higher. In the present invention, any artificial graphite can be used as a raw material as long as it exhibits high orientation and high electrochemical capacity after mechanical energy treatment and heat treatment.

The mechanical energy treatment of these carbon materials is performed so that the average particle size ratio before and after the treatment becomes 1 or less. The “average particle size ratio before and after treatment” is a value obtained by dividing the average particle size after treatment by the average particle size before treatment. The average particle size here is a volume-based particle size distribution measured by a laser-type particle size distribution analyzer. When measured with a laser-type particle size distribution analyzer, particles having anisotropic shape can be averaged isotropically to obtain a particle size distribution substantially converted into a sphere.

In the mechanical energy treatment for producing the carbon material for an electrode according to the present invention, the average particle size ratio before and after the treatment is set to 1 or less. On the other hand, when granulated, the average particle diameter ratio becomes 1 or more, and the tap density also increases. The granulated powder is not preferable because it is fully expected that the powder will return to the state before the treatment in the final molding process.

In the mechanical energy treatment, the particle size is reduced so that the average particle size ratio before and after the treatment of the powder particles becomes 1 or less, and at the same time, the particle shape is controlled. Grinding,
Among the engineering unit operations that can be used for particle design such as classification, mixing, granulation, surface modification, and reaction, mechanical energy processing belongs to pulverization processing.

Pulverization refers to applying a force to a substance to reduce its size and adjust the particle size, particle size distribution, and filling properties of the substance. The pulverization treatment is classified according to the type of force applied to the substance and the treatment form. The force applied to a substance is roughly divided into four types: a breaking force (impact force), a crushing force (compression force), a crushing force (grinding force), and a shaving force (shearing force). On the other hand, the treatment mode is roughly classified into two types: volume pulverization in which cracks are generated and propagated inside the particles, and surface pulverization in which the particle surface is scraped off. Volume pulverization proceeds by impact force, compression force, and shear force, and surface pulverization proceeds by attrition force and shear force. Grinding is a process in which the types of forces applied to these substances and the processing modes are variously combined. The combination can be appropriately determined according to the processing purpose.

The pulverization may be performed by using a chemical reaction such as blasting or volume expansion, but is generally performed by using a mechanical device such as a pulverizer. The pulverization treatment used in the production of the carbon material for an electrode of the present invention is preferably such that the ratio of the surface treatment finally increases irrespective of the presence or absence of volume pulverization. This is because surface crushing of the particles is important to bevel the graphite or carbonaceous particles and introduce roundness into the particle shape. Specifically, surface treatment may be performed after volume pulverization proceeds to some extent,
Only the surface treatment may be performed without substantially proceeding the volume pulverization, or the volume pulverization and the surface treatment may be performed simultaneously. Finally, it is preferable to perform a pulverization treatment so that the surface pulverization progresses and the corners are removed from the surface of the particles.

The apparatus for performing the mechanical energy processing is selected from those capable of performing the above-described preferable processing. Examinations by the present inventors have revealed that a device that repeatedly applies mechanical effects such as compression, friction, and shear force to particles, mainly by impact force, including particle interaction, is effective. Specifically, the casing has a rotor with a large number of blades installed inside, and the rotor rotates at a high speed, so that the carbon material introduced into the casing can be subjected to mechanical compression, friction, shear, etc. It is preferable to use a device that performs a surface treatment while imparting an effective action and performing volume pulverization. Further, it is more preferable to have a mechanism for repeatedly giving a mechanical action by circulating or convection the carbon material.

As an example of such a preferred device,
A hybridization system manufactured by Nara Machinery Co., Ltd. can be mentioned. When processing is performed using this apparatus, the peripheral speed of the rotating rotor is set to 30 to 100 m /
It is preferably set to seconds, more preferably from 40 to 100 m / sec, and even more preferably from 50 to 100 m / sec. In addition, the treatment can be carried out by simply passing the carbon material. However, the treatment is preferably carried out by circulating or staying in the apparatus for 30 seconds or more, and is preferably carried out by circulating or staying in the apparatus for 1 minute or more. More preferred.

The true density of the carbonaceous powder used as the raw material is 2.25.
When the crystallinity is not so high and the crystallinity is not so high, it is preferable to perform a heat treatment for further increasing the crystallinity after performing the mechanical energy treatment. The heat treatment is preferably performed at 2000 ° C. or higher, more preferably at 2500 ° C. or higher, and still more preferably at 2800 ° C. or higher. By performing such a mechanical energy treatment, the graphitic particles or the carbonaceous particles become coarse only in the vicinity of the surface of the particles while maintaining high crystallinity as a whole, and are distorted and particles having exposed edge surfaces. Become. This increases the surface through which lithium ions can enter and exit, and has a high capacity even at a high current density.

As an index of the crystallinity of the particles and the roughness of the particle surface, that is, the abundance of the edge surface of the crystal, the (002) plane spacing (d002), the crystallite size (Lc), it can be used an R value which is the peak intensity ratio of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectrum. Generally, the carbon material has a plane spacing (d) of (002) plane.
The smaller the value of (002) and the larger the crystallite size (Lc), the smaller the R value. That is, the entire graphite or carbonaceous particles are in substantially the same crystalline state. On the other hand, the carbon material for an electrode of the present invention has a small value of the spacing (d002) of the (002) plane and a large crystallite size (Lc), but has a large R value. That is, the crystallinity of the carbon material bulk is high, but the crystallinity in the vicinity of the surface of the carbon particles (up to about 100 ° from the particle surface) is disordered, indicating that the edge surface is exposed more. This mechanical energy treatment also introduces roundness into the particles,
The filling property of these particles can be improved.

It is known that in order to enhance the filling property of powder particles, it is better to fill smaller particles that can enter the voids formed between the particles. For this reason, it is conceivable that the carbonaceous or graphitic particles may be subjected to a treatment such as pulverization to reduce the particle size, thereby improving the filling property. On the contrary, the filling property is reduced. It is considered that this is because the particle shape becomes more irregular when crushed.

On the other hand, as the number of particles (coordination number n) in contact with one particle (particle of interest) in the powder particle group increases, the proportion of the voids in the packed bed decreases. That is,
As factors affecting the packing ratio, the particle size ratio and the composition ratio, that is, the particle size distribution are important. However, this study was carried out with a model spherical particle group, and the carbonaceous or graphitic particles before treatment handled in the present invention are flaky, scaly, plate-like, Even if an attempt is made to increase the filling rate by controlling the particle size distribution only by pulverization, classification, and the like, it is not possible to produce such a high filling state.

In general, flaky, scaly, and plate-like carbonaceous or graphitic particles tend to have poorer filling properties as the particle size decreases. This is because the particles become more irregular due to the pulverization, and the surface of the particles is increased in the form of protrusions such as "scratch" and "peeling off" and "bends". It is considered that the resistance between adjacent particles is increased due to the irregular particles being attached with a certain strength or the like, thereby deteriorating the filling property.
These irregularities are reduced, and if the particle shape approaches a spherical shape, the decrease in the packing property is reduced even if the particle size is reduced, and theoretically, the same degree of carbon particles in both large particle size carbon powder and small particle size carbon It should indicate tap density.

Investigations by the present inventors have confirmed that, for carbonaceous or graphitic particles having substantially the same true density and substantially the same average particle size, the more spherical the shape, the higher the tap density. I have. That is, it is important that the shape of the particles be rounded and approximate to a spherical shape. If the particle shape approaches a spherical shape, the filling property of the powder is also greatly improved. In the present invention, for the above reason, the tap density of the powder is used as an index of the degree of spheroidization. When the filling property of the granular material after the treatment is higher than that before the treatment, it can be considered that the particles are spheroidized by the treatment method used. Further, in the method of the present invention, the tap density of the carbon material obtained when the treatment is performed while greatly reducing the particle size is higher than the tap density of the carbon material having the same particle size obtained by general pulverization. If so, it can be considered as a result of spheroidization.

In the present invention, it is also possible to use carbonaceous or graphitic particles which have been subjected to mechanical energy treatment and then classified to remove fine powder and / or coarse components. A known method can be used for classification. By performing the above process, R value is the peak intensity ratio of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectrum is 0.0
A raw graphite powder having a (002) plane spacing (d002) of less than 0.337 nm and a crystallite size (Lc) of 90 nm or more by wide-angle X-ray diffraction at 1 to 0.25 is subjected to mechanical energy treatment. the by performing an argon ion laser R value is the peak intensity ratio of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the Raman spectrum is more than 1.5 times the R value of the graphite powder before treatment, preferably at least 2-fold The upper limit is not particularly limited, but usually 10 times or less, preferably 7 times or less can be employed, and the (002) plane spacing (d002) by the wide-angle X-ray diffraction method is 0.337 n.
m, the crystallite size (Lc) is 90 nm or more,
Further, a carbon material for an electrode, which is a treated graphite powder having a tap density of 0.75 g / cm ³ or more, can be provided.

The multi-layered carbon material for an electrode of the present invention is obtained by mixing an organic compound to be carbonized in a firing step with the carbon material for an electrode of the present invention having the above-mentioned properties. It can be prepared by carbonizing an organic compound. The type of the organic compound mixed with the electrode carbon material is not particularly limited as long as it can be carbonized by firing.
Therefore, an organic compound that progresses carbonization in a liquid phase or an organic compound that progresses carbonization in a solid phase may be used. The organic compound to be mixed with the electrode carbon material may be a single organic compound or a mixture of a plurality of types of organic compounds.

As an organic compound which promotes carbonization in a liquid phase, coal tar pitch from soft pitch to hard pitch,
Coal-based heavy oil such as coal liquefied oil, DC-based heavy oil such as asphaltenes, petroleum-based heavy oil such as naphthatar-derived cracked heavy oil, etc., which is by-produced during thermal cracking of crude oil and naphtha, cracked heavy Heat-treated pitches such as ethylene tar pitch, FCC decant oil, and ashland pitch obtained by heat-treating the oil can be used. Furthermore, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral,
Vinyl-based polymers such as polyvinyl alcohol and substituted phenol resins such as 3-methylphenol formaldehyde resin and 3,5-dimethylphenol formaldehyde resin, aromatic hydrocarbons such as acenaphthylene, decacyclene and anthracene, and nitrogen ring compounds such as phenazine and acridine And substances such as sulfur ring compounds such as thiophene.

Examples of the organic compound that promotes carbonization in the solid phase include natural polymers such as cellulose, chain vinyl resins such as polyvinylidene chloride and polyacrylonitrile, aromatic polymers such as polyphenylene, and furfuryl alcohol resin. , Phenol-formaldehyde resin,
Examples thereof include thermosetting resins such as imide resins and thermosetting resin raw materials such as furfuryl alcohol. In addition, these organic compounds can be used by adhering to the surface of the powder particles by appropriately dissolving and diluting a solvent as necessary, if necessary. As a method for producing the multilayered carbon material for an electrode of the present invention from these organic compounds and the carbon material for an electrode, a typical production method comprising the following steps can be exemplified.

(First step) A step of mixing a carbon material for an electrode and an organic compound together with a solvent, if necessary, using various commercially available mixers, kneaders and the like to obtain a mixture. (Second step) (Step to be carried out as necessary) A step of heating the mixture as it is or while stirring as necessary to obtain an intermediate substance from which the solvent has been removed. (Third step) a step of heating the mixture or the intermediate substance to 500 to 3000 ° C. in an inert gas atmosphere such as nitrogen gas, carbon dioxide gas, argon gas or the like or a non-oxidizing atmosphere to obtain a carbonized substance. (Fourth step) (Steps to be performed as necessary) Steps of powder processing such as pulverization, crushing, and classification of the carbonized material.

In the mixing in the first step, a solvent may or may not be used. When a solvent is used, the type and amount thereof are not particularly limited, but a solvent that dissolves the organic compound used or reduces the viscosity is preferable. The temperature at the time of mixing is also not particularly limited, but is, for example, from room temperature to 300 ° C. or lower, preferably from room temperature to 200 ° C.
C. or lower, more preferably room temperature to 100 C. or lower. In the first step, by mixing the organic compound and the electrode carbon material, the organic compound can be attached to the surfaces of the powder particles of the electrode carbon material. The heating temperature in the second step is usually 300 ° C. or higher, preferably 400 ° C.
The above is more preferably 500 ° C. or higher, and the upper limit is not particularly limited, but 3000 ° C. or lower, preferably 2800 ° C.
The temperature is more preferably 2500 ° C. or lower, particularly preferably 1500 ° C. or lower. Although the second step can be omitted, the third step is usually performed after the second step is performed to obtain an intermediate substance.

In the heat treatment of the third step, the heat history temperature condition is important. The lower limit temperature is slightly different depending on the kind of organic compound and heat history, but is usually 500 ° C. or higher, preferably 700 ° C. or higher, more preferably 900 ° C. or higher. The upper limit temperature is usually 3000 ° C. or lower, preferably 280 ° C.
The temperature is 0 ° C. or lower, more preferably 2500 ° C. or lower, particularly preferably 1500 ° C. or lower. The heating rate, cooling rate, heat treatment time, and the like can be arbitrarily set according to the purpose. After the heat treatment in a relatively low temperature range, the temperature can be raised to a predetermined temperature. The fourth step is a step in which powder processing is performed by performing pulverization, crushing, spheroidization and the like as necessary, but can be omitted. Further, the fourth step can be performed before the third step, or both before and after the third step. The reactor used in these steps may be a batch type or a continuous type. In addition, one group or a plurality of groups may be used.

In the multilayer carbon material for an electrode of the present invention,
The ratio of carbonaceous matter derived from organic compounds (hereinafter referred to as “coverage”)
Is usually 0.1 to 50% by weight, preferably 0.5 to 2% by weight.
5% by weight, more preferably 1 to 15% by weight, even more preferably
Or 2 to 10% by weight. Also book
The multilayered carbon material for an electrode of the present invention has a volume-based average particle size.
2 to 70 μm, preferably 4 to 40 μm, more preferably
Is 5 to 35 μm, more preferably 7 to 30 μm.
You. The specific surface area measured using the BET method is, for example, 0.1
-10m ^Two/ G, preferably 1 to 10 m^Two/ G, more preferred
Or 1-7m^Two/ G, particularly preferably 1-4 m^Two/ G
is there. Further, the multilayered carbon material for an electrode of the present invention has C
In the diffractogram of X-ray wide angle diffraction using uKα ray as a source,
Exceeds the crystallinity of nucleated carbonaceous or graphitic particles
Preferably not.

The multi-layered carbon material for an electrode of the present invention was analyzed by Raman spectrum analysis using an argon ion laser beam having a wavelength of 5145 cm ⁻¹ , at 1580 to 1620 cm 2.
^-1 peak PB in the range of 1350-1370 cm ^-1 with respect to peak PA (peak intensity IA) appearing in the range of ^-1
The R value represented by the ratio “IB / IA” of (peak intensity IB) is preferably 0.1 to 0.7, more preferably 0.20 to 0.7, and particularly preferably 0.25 to 0.6. It is. The tap density is 0.70 to 1.40 g / cm.
³ , preferably 0.75 to 1.40 g / cm ³ , more preferably 0.85 to 1.40 g / cm ³ . With the multilayer structure, the tap density of the electrode carbon material may be further improved, and the shape may have an effect of further introducing roundness. The carbon material for an electrode of the present invention has a rough particle surface,
When used for the multi-layer structure carbon material for an electrode of the present invention, an effect of increasing the binding property with the coated carbonaceous material can be expected.

Electrode An electrode can be manufactured using the carbon material for an electrode or the multilayered carbon material for an electrode of the present invention. In particular, the multi-layered carbon material for an electrode of the present invention can be very preferably used for manufacturing an electrode. The production method is not particularly limited, and it can be produced according to a generally used method. As a typical method, a binder or a solvent is added to a carbon material for an electrode or a multilayer structure carbon material for an electrode to form a slurry, and the obtained slurry is applied to a metal current collector substrate such as a copper foil. A method of applying and drying can be given. In addition, by applying and drying the carbon material for electrode or multi-layer structure carbon material for electrode by roll press, compression molding machine, etc., the packing density of the electrode plate is improved and the amount of electrode per unit volume is increased. Can be done. Further, the carbon material for an electrode or the multilayered carbon material for an electrode can be formed into an electrode shape by a method such as compression molding.

Examples of the binder that can be used in the production of the electrode include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, and cellulose, styrene-butadiene rubber, and isoprene rubber that are stable to solvents. , Butadiene rubber, ethylene
Rubbery polymers such as propylene rubber, styrene / butadiene / styrene block copolymers, hydrogenated products thereof, styrene / ethylene / butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers, hydrogenated products thereof Soft resinous polymers such as thermoplastic elastomeric polymers such as syndiotactic 1,2-polybutadiene, ethylene / vinyl acetate copolymer, propylene / α-olefin (2 to 12 carbon atoms) copolymer, and polyolefin. Fluorinated polymers such as vinylidene fluoride, vinylidene fluoride / hexachloropropylene copolymer, polytetrafluoroethylene, polytetrafluoroethylene / ethylene copolymer, and a polymer composition having lithium ion ionic conductivity Things are also mentioned.

Examples of the polymer having ion conductivity include polyether polymer compounds such as polyethylene oxide and polypropylene oxide, crosslinked polymers of polyether compounds, polyepichlorohydrin, polyphosphazene, polysiloxane, polyvinylpyrrolidone, and polyvinylidene. Carbonates, polyacrylonitrile and other high molecular compounds, lithium salts, or a composite system of lithium-based alkali metal salts, or organic compounds having a high dielectric constant such as propylene carbonate, ethylene carbonate, γ-butyrolactone And a low viscosity organic compound such as a linear carbonate. The ionic conductivity of such an ion-conductive polymer composition at room temperature is preferably 10 ^-5 s / cm or more, more preferably 10 ^-3 s / cm or more.

Various forms can be adopted as a mixed form of the electrode carbon material or the multilayer carbon material for the electrode and the binder. For example, a form in which both particles are mixed, a form in which a fibrous binder is entangled with the carbonaceous material particles, or a form in which a layer of the binder is attached to the surface of the carbonaceous material particles, and the like. it can. The mixing ratio of the two is preferably set to 0.1 to 30% by weight of the binder with respect to the electrode carbon material or the multi-layer structure carbon material for the electrode.
More preferably, the content is 10 to 10% by weight. When the binder is added in an amount of 30% by weight or more, the internal resistance of the electrode increases. On the other hand, in the case of 0.1% by weight or less, the binding property between the current collector and the carbon material for the electrode or the multilayer structure carbon material for the electrode is poor. There is a tendency.

The electrode made of the carbon material for an electrode or the multi-layered carbon material for an electrode of the present invention has a density of an active material layer on the electrode which has been compacted by roll pressing or compression molding (hereinafter referred to as electrode density). ) From 0.5 to 1.7 g / c
m ³ , preferably 0.7 to 1.6 g / cm ³ , and more preferably 0.7 to 1.55 g / cm ³ , the capacity per unit volume of the battery without impairing high-efficiency discharge and low-temperature characteristics. Can be extracted to the maximum. At this time, the carbon material for an electrode or the multilayered carbon material for an electrode of the present invention has a high charge / discharge capacity due to the high crystallinity inside the particles, and the surface of the particles is rough, that is, from the surface of the particles to the edge. Part is exposed, or the particle shape such that the abundance of the edge part increases (pulverized in the direction perpendicular to the plane of the plate-like particle and the thickness direction in the particle becomes relatively thick,
That is, the area of the carbon material for the electrode or the carbon material particles for the multilayer structure carbon material for the electrode is increased by doping or undoping lithium ions into the carbon material particle for the electrode or the carbon material particle for the electrode. In addition, since the tap density is high, that is, the carbon material is nearly spherical, the voids in the electrode are less likely to be closed, so that diffusion of lithium ions can be performed more smoothly.

Secondary Battery The carbon material for an electrode and the multilayered carbon material for an electrode of the present invention are useful as an electrode of a battery. In particular, it is extremely useful as a negative electrode material for non-aqueous secondary batteries such as lithium secondary batteries. For example, a non-aqueous secondary battery configured by combining an organic electrolyte mainly composed of a metal chalcogenide-based positive electrode and a carbonate-based solvent for a lithium ion battery and a negative electrode manufactured according to the above method has a large capacity. , The irreversible capacity observed in the initial cycle is small, the rapid charge and discharge capacity is high, and the cycle characteristics are excellent,
The battery has high storage stability and high reliability when left at high temperatures, and is extremely excellent in high-efficiency discharge characteristics and low-temperature discharge characteristics. There is no particular limitation on the selection of members necessary for the battery configuration, such as the positive electrode and the electrolyte, which constitute such a non-aqueous secondary battery. In the following, the materials and the like of the members constituting the non-aqueous secondary battery are exemplified, but the materials that can be used are not limited to these specific examples.

The positive electrode constituting the non-aqueous secondary battery of the present invention includes, for example, a lithium transition metal composite oxide material such as lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide; Oxide materials; materials that can occlude and release lithium, such as carbonaceous materials such as fluorinated graphite, can be used. Specifically, LiFeO ₂ , LiCoO ₂ , LiNiO ₂ , LiM
n ₂ O ₄ and their non-stoichiometric compounds, MnO ₂ , Ti
S ₂ , FeS ₂ , Nb ₃ S ₄ , Mo ₃ S ₄ , CoS ₂ , V
₂ O ₅ , P ₂ O ₅ , CrO ₃ , V ₃ O ₃ , TeO ₂ , GeO _{2 and the} like can be used. The method for manufacturing the positive electrode is not particularly limited, and the positive electrode can be manufactured by the same method as the above-described method for manufacturing the electrode.

For the positive electrode current collector used in the present invention, it is preferable to use a valve metal or an alloy thereof which forms a passive film on the surface by anodic oxidation in an electrolytic solution. Examples of the valve metal include metals belonging to groups IIIa, IVa, and Va (groups 3B, 4B, and 5B) and alloys thereof. Specifically, Al, Ti, Zr, Hf, Nb, Ta and alloys containing these metals can be exemplified.
l, Ti, Ta and alloys containing these metals can be preferably used. In particular, Al and its alloys are desirable because of their light weight and high energy density.

As the electrolytic solution used in the non-aqueous secondary battery of the present invention, a solution obtained by dissolving a solute (electrolyte) in a non-aqueous solvent can be used. As the solute, an alkali metal salt, a quaternary ammonium salt, or the like can be used. Specifically, LiClO ₄ , LiPF ₆ , LiBF ₄ , LiC
F ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF
₂ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), L
It is preferable to use one or more compounds selected from the group consisting of iC (CF ₃ SO ₂ ) ₃ .

As the non-aqueous solvent, ethylene carbonate, propylene carbonate, butylene carbonate,
Cyclic carbonates such as vinylene carbonate, cyclic ester compounds such as γ-butyrolactone; chain ethers such as 1,2-dimethoxyethane; crown ethers;
Cyclic ethers such as methyltetrahydrofuran, 1,2-dimethyltetrahydrofuran, 1,3-dioxolan, and tetrahydrofuran; and linear carbonates such as diethyl carbonate, ethylmethyl carbonate, and dimethyl carbonate can be used. One solute and one solvent may be selected and used, respectively, or two or more may be used as a mixture. Among these, those in which the non-aqueous solvent contains a cyclic carbonate and a chain carbonate are preferred.

The material and shape of the separator used in the non-aqueous secondary battery of the present invention are not particularly limited. The separator separates the positive electrode and the negative electrode so that they do not come into physical contact with each other, and preferably has high ion permeability and low electric resistance. Preferably, the separator is selected from materials that are stable with respect to the electrolytic solution and have excellent liquid retention properties. Specifically, using a porous sheet or nonwoven fabric made of a polyolefin such as polyethylene or polypropylene as a raw material,
The above electrolyte can be impregnated.

The method for producing the non-aqueous electrolyte secondary battery of the present invention having at least a non-aqueous electrolyte, a negative electrode and a positive electrode is not particularly limited, and can be appropriately selected from commonly employed methods. For the non-aqueous electrolyte secondary battery of the present invention, an outer can, a separator, a gasket, a sealing plate, a cell case, and the like can be used, if necessary, in addition to the non-aqueous electrolyte, the negative electrode, and the positive electrode. The manufacturing method is, for example, placing the negative electrode on the outer can, providing an electrolytic solution and a separator thereon,
Furthermore, the positive electrode is placed so as to face the negative electrode, and the battery can be caulked together with the gasket and the sealing plate. The shape of the battery is not particularly limited, and may be a cylinder type in which a sheet electrode and a separator are spirally formed, a cylinder type having an inside-out structure in which a pellet electrode and a separator are combined, a coin type in which a pellet electrode and a separator are stacked, and the like. .

[0061]

The present invention will be described more specifically with reference to specific examples. The materials, amounts, proportions,
The operation and the like can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples described below.

Example 1 18 kinds of carbon materials for electrodes were prepared by treating a predetermined amount of graphite raw material shown in Table 1 under the processing conditions shown in Table 1. The types of graphite raw materials used as raw materials are as shown in Table 3. Table 1 shows the results of measuring the physical properties of the 18 prepared carbon materials for electrodes by the measuring method described later.

[0063]

[Table 1]

(Example 2) Carbon material 3 described in Table 2
kg and 1 kg of petroleum-based tar are transferred from Matsubo M Co., Ltd.
The mixture was charged into a 20-type Reigeger mixer (internal volume: 20 liters) and kneaded. Then, 700 under nitrogen atmosphere
After the temperature was raised to 0 ° C. to remove the tar, a heat treatment was performed by increasing the temperature to 1300 ° C. The obtained heat-treated product was pulverized with a pin mill, and subjected to a classification treatment for the purpose of removing coarse particles. Finally, 13 types of multilayered carbon materials for electrodes were prepared. Table 2 shows the results obtained by measuring the physical properties of the 13 prepared multilayer structure carbon materials for electrodes by the measurement method described below.

[0065]

[Table 2]

The details of the graphite materials used in Examples 1 and 2 are shown in Table 3 below.

[0067]

[Table 3]

The methods for measuring the physical properties of the carbon materials prepared in Examples 1 and 2 are described below. (1) X-ray diffraction X-ray standard high-purity silicon powder of about 15% is added to and mixed with the carbon material for an electrode, and the obtained mixture is packed in a sample cell.
A wide angle X-ray diffraction curve was measured by a reflection type diffractometer method using a CuKα ray monochromatized by a graphite monochromator as a radiation source, and the plane spacing (d0) was determined by the Gakushin method.
02) and crystallite size (Lc). (2) Raman analysis Raman spectrum analysis was performed using NR-1800 manufactured by JASCO Corporation. The analysis was performed by using argon ion laser light having a wavelength of 514.5 nm, setting the laser power to 30 mW, and setting the exposure time to 75 seconds. The laser power is 30 mW in the light source section, and 18 m in the measurement sample section due to laser light attenuation in the optical path between the light source and sample sections.
W. The sample was filled into the measurement cell by allowing the electrode carbon material to fall naturally, and the measurement was performed while irradiating the sample surface inside the cell with laser light and rotating the cell in a plane perpendicular to the laser light. The intensity IA of the peak PA near 1580 cm ^-1 of the obtained Raman spectrum,
Measure the intensity IB of the peak PB near 1360 cm ^-1 ,
The intensity ratio (R = IB / IA) and the half width of the peak near 1580 cm ^-1 were measured. Further, the area of the peak PA around the 1580 cm ^-1 (integrated value of 1480~1680cm ^-1) YA, (integral value of 1260~1460cm ^-1) area of the peak PB around the 1360 cm ^-1 to the YB, its The value of the area ratio G = YA / YB was measured.

[0069] (3) using the tap density powder density measuring instrument (Inc. Seishin Enterprise Co., Ltd. Tap Denser KYT-3000), using a mesh opening 300μm sieve as sieve electrode carbon material passes, 20 cm ³
After the powder was dropped into the tap cell of No. 1 to completely fill the cell, tapping with a stroke length of 10 mm was performed 1,000 times, and the tap density at that time was measured. (4) True density Using a 0.1% aqueous surfactant solution, the true density was measured by a liquid phase replacement method using a pycnometer. (5) BET specific surface area AMS-8000 manufactured by Okura Riken Co., Ltd. was heated to 350 ° C. for predrying, nitrogen gas was flowed for 15 minutes, and then measured by the BET one-point method by nitrogen gas adsorption. (6) Average particle size A 2% by volume aqueous solution (about 1 ml) of polyoxyethylene (20) sorbitan monolaurate as a surfactant is mixed with a carbon material for an electrode, and a laser diffraction particle size is obtained by using ion exchange water as a dispersion medium. Distribution meter (LA-700 manufactured by Horiba, Ltd.)
The average particle size (median diameter) on a volume basis was measured at.

(7) Average circularity Flow type particle image analyzer (FPIA- manufactured by Toa Medical Electronics Co., Ltd.)
2000) was used to measure the particle size distribution based on the circle equivalent diameter and calculate the circularity. Ion-exchanged water is used as a dispersion medium, and polyoxyethylene (2
0) Sorbitan monolaurate was used. The circle equivalent diameter is a circle (equivalent circle) having the same projected area as the captured particle image
And the degree of circularity is a ratio of the perimeter of the equivalent circle as a numerator and the perimeter of the captured particle projection image as a denominator. The circularity of all the measured particles was averaged to obtain an average circularity.

(8) Coverage of Multi-layered Carbon Material The coverage of the multi-layered carbon material was determined by the following equation.

## EQU3 ## Coverage (% by weight) = 100− (K × D) / (N
× (K + T)) × 100 In the above formula, K is the weight of the carbon material (kg), T is the weight of the petroleum tar (kg), and D is the weight (kg) of the kneaded material before the detar treatment (second step). ) And N represent the recovered amount (kg) of the heat-treated product after the heat treatment (third step).

Example 3 A semi-electric field was prepared using the prepared carbon material, and the charge and discharge properties were tested. (1) Preparation of Half Battery A 5% carbon material was added with a solution of polyvinylidene fluoride (PVdF) in dimethylacetamide at 10% by weight in terms of solid content, and the mixture was stirred to obtain a slurry. This slurry was applied on a copper foil by a doctor blade method, and pre-dried at 80 ° C. Further, after being compacted by a roll press machine so that the electrode density becomes 1.4 g / cm ³ or 1.5 g / cm ³ , it is punched into a disc having a diameter of 12.5 mm, and dried under reduced pressure at 110 ° C. And Thereafter, a coin cell in which an electrode and a lithium metal electrode were opposed to each other centering on a separator impregnated with an electrolytic solution was prepared, and a charge / discharge test was performed. As the electrolytic solution, a solution prepared by dissolving lithium perchlorate at a ratio of 1.5 mol / l in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a weight ratio of 2: 8 was used.

(2) Measurement of irreversible capacity The battery was charged to 0 V at a current density of 0.16 mA / cm ² (lithium ion doping of the electrode), and then the current density was increased to 0.
The value obtained by subtracting the first discharge capacity from the first charge capacity when discharging to 1.5 V at 33 mA / cm ² (lithium ion undoping from the electrode) was defined as the irreversible capacity. (3) discharge capacity and discharge rate property (quick discharging characteristics) of the measured current density 0.16 mA / cm charging to 0V at ² and current density 0.33 mA / cm ² 3 times the discharge to 1.5V at Repeatedly, the third discharge capacity at that time was defined as “discharge capacity”. Next, charging was performed at a current density of 0.16 mA / c.
It performed in m ² to 0V, discharging each current density 2.8m
A / cm ^2, carried out at 5.0 mA / cm ² until 1.5V, and the discharge capacity obtained capacity at each current density 2.8 mA / cm ² and 5.0 mA / cm ^2, an indication of rapid discharge characteristics And The results of these tests are summarized in Table 4 below.

[0074]

[Table 4]

Example 4 The electrode carbon material No. 1 prepared in Example 1 was used. 11 using an air classifier “MC-100” manufactured by Seishin Enterprise Co., Ltd. under the conditions of removing 25% by weight of fine powder and 22% by weight of coarse powder, respectively. Diameter = 20.8 μm, d002 = 0.
336 nm, BET specific surface area = 5.3 m ² / g, tap density = 0.82 g / cm ³ , Lc> 100 nm, true density = 2.26 g / cm ³ , Raman R value = 0.25, Raman 1580 half width = An electrode carbon material having physical properties of 22.0 cm ^-1 was obtained. Next, an experiment was carried out in the same manner as in Example 2 except that this carbon material for an electrode was used, to obtain a multilayer carbon material for an electrode having the following physical properties. Raman R value =
0.37, Raman 1580 half width = 29.5 cm ⁻¹ , tap density = 0.99 g / cm ³ , BET specific surface area = 2.
3 m ² / g, average particle size = 24.6 μm, coverage = 4.9
weight%. A half-cell was prepared in the same manner as in Example 3 except that the multilayer carbon material obtained above was used, and the charge / discharge property was tested. As a result, the electrode density = 1.5 g / c
m ³ , first irreversible capacity = 17 mAh / g, 0.33 A /
cm ³ discharge capacity = 352 mAh / g, 2.8 mA / cm ³
Rapid discharge capacity = 351 mAh / g, 5.0 mA / cm ³
The rapid discharge capacity was 334 mAh / g, indicating good characteristics.

[0076]

The battery using the carbon material for an electrode or the multilayered carbon material for an electrode of the present invention has a capacity (0.33 m).
A / cm ³ discharge capacity), the irreversible capacity observed in the initial cycle is small, and the cycle capacity retention rate is excellent. More particularly rapid charge and discharge,
(5.0 mA / cm ³ rapid discharge capacity) is greatly improved. Further, the battery has high storage stability and reliability when left at high temperatures, and has excellent discharge characteristics at low temperatures. Therefore, the carbon material for an electrode and the multi-layer structure carbon material of the present invention can be effectively used for manufacturing batteries such as lithium batteries.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G046 CA00 CA05 CA06 CA07 CB02 CB08 CB09 CC01 5H003 AA02 AA03 BA01 BB01 BB02 BB12 BC05 BD00 BD02 BD03 BD05 5H029 AJ02 AJ03 AJ04 AK03 AK05 AK06 AL06 AL07 AM01 AM02 AM03 AM07 BJ03 BJ14 CJ02 DJ16 DJ17 HJ02 HJ05 HJ07 HJ08 HJ13

Claims (9)

[Claims] 1. A (002) plane obtained by a wide-angle X-ray diffraction method
Spacing (d002) less than 0.337 nm, crystallite size
(Lc) 90 nm or more, argon ion laser llama
1580 cm in the spectrum^-1Of peak intensity
1360cm ^-1R value which is the peak intensity ratio of 0.2
0 or more and tap density 0.75 g / cm^ThreeIs over
A carbon material for an electrode, characterized in that: 2. The carbon material for an electrode according to claim 1, wherein the true density is 2.21 g / cm ³ or more. 3. The carbon material for an electrode according to claim 1, wherein the BET specific surface area is less than 18 m ² / g. 4. The carbon material for an electrode according to claim 1, wherein the average particle size is 2 to 50 μm. 5. Argon ion laser Raman spectrum
1580cm ^-1The half width of the peak is 20 cm
^-1The method according to any one of claims 1 to 4, wherein
The carbon material for an electrode according to 1. 6. A multi-layer carbon material for an electrode produced by mixing the carbon material according to claim 1 with an organic compound and then carbonizing the organic compound. 7. A non-aqueous electrolyte secondary battery comprising a negative electrode, a positive electrode, and a non-aqueous electrolyte comprising a solute and a non-aqueous solvent, comprising a carbonaceous material capable of inserting and extracting lithium. A non-aqueous secondary battery, wherein at least a part of the carbonaceous material is the carbonaceous material according to claim 1. 8. The method according to claim 1, wherein the solute is LiClO ₄ , LiPF ₆ ,
LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ ,
LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ )
_{(C 4 F 9 SO 2)} , a non-aqueous secondary battery according to claim 7 which is 1 or more compounds selected from the group consisting of _{LiC (CF 3 SO 2) 3} . 9. The non-aqueous secondary battery according to claim 7, wherein the non-aqueous solvent contains a cyclic carbonate and a chain carbonate.