JPH10334915A - Electrode for nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode having a high electrode filling property of a material and a high energy density and superior in quick charging/discharging property by using carbon or graphite grains applied with a dynamic energy process, so that the apparent density ratio and median diameter ratio between before and after the process are in the specific ranges. SOLUTION: A dynamic energy process is applied to carbon or graphite grains so that the apparent density ratio between before and after the process becomes 1.1 or above, and the median diameter ratio between before and after the process becomes 1 or below. The dynamic energy process is specifically pulverization, roundness is introduced to the grain shape, and the filling property of the carbon or graphite grains is increased. The apparent density ratio between before and after the process = tap density after the process/tap density before the process, and this is to become the index of sphericity. The median diameter ratio between before and after the process = median diameter after the process/median diameter before the process, and it is the median diameter ratio of the volume reference grain size distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrode for a non-aqueous secondary battery using graphite particles. More specifically, the present invention relates to a non-aqueous secondary battery electrode having a high capacity and good rapid charge / discharge properties.

[0002]

2. Description of the Related Art In recent years, high-capacity secondary batteries 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. However, during repeated charging and discharging, lithium precipitated in a resinous (dendrite) form, penetrated through the separator, reached the positive electrode, and short-circuited both electrodes. It turned out that there was a possibility. Therefore, attention has been paid to a carbon-based material that can prevent the generation of dendrite instead 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 strengths and make up 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, graphite materials that are highly crystalline and commercially available generally have a flake-like, scale-like, or plate-like particle shape. When these graphitic particles are made into an electrode through the above-mentioned electrode plate manufacturing process, the electrode plate density increases in accordance with the degree of compression, but on the other hand, the particle gap is not sufficiently secured, so that the movement of lithium ions is hindered, There is a problem that the rapid charge / discharge property of the battery is reduced. Further, when the plate-like graphite particles are molded as an electrode, the plate surface of the powder is arranged with a high probability in parallel with the electrode plate surface due to the effect of the slurry application step and the electrode compression step. . 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, there is a problem in that the free flow of the electrolyte solution outside the electrode is hindered, so that the movement of lithium ions is hindered.

On the other hand, graphitized mesocarbon microbeads having a spherical shape have been proposed and already commercialized as a negative electrode material for securing a void necessary for the movement of lithium ions in an electrode plate. If the morphology 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 The moving speed is well maintained. Furthermore, the void remaining inside the electrode is derived from its particle shape,
Since the electrode is connected to the outside of the electrode, the movement of lithium ions is relatively free, and the electrode structure has a structure capable of coping with rapid charge and discharge. However, it is widely known that mesocarbon microbeads have a low electric capacity limit of 300 mAh / g due to a low macroscopic ordered structure, and are inferior to scaly, scaly, and 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. JP-A-8-180873 is an invention in which the ratio of scale-like particles to particles that are relatively non-scale-like is specified, and JP-A-8-83610 contradicts that scale-like particles are preferred. Practical batteries are required to have electrodes having both high electric capacity and rapid charge / discharge properties, and it is desired to improve the rapid charge / discharge properties of flaky, scaly, and plate-like graphite materials. Therefore, an object of the present invention is to provide an electrode for a non-aqueous secondary battery, which has a high electrode filling property of a material, a high energy density, and an excellent rapid charge / discharge property.

[0008]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors to achieve the above object, the shape and filling property of the graphite material are important for improving the performance of the electrode. There is a high capacity, rapid charge / discharge, and cycle characteristics combined by using spheroidized graphite and carbonaceous particles obtained by processing a graphite material having a high electrochemical capacity into a spherical shape, They have come to the knowledge that excellent electrodes can be obtained.

The electrode for a non-aqueous secondary battery of the present invention has been completed based on such findings, and has an apparent density ratio of 1.1 or more before and after treatment and a median diameter ratio before and after treatment. It is characterized by using carbonaceous or graphitic particles which have been subjected to mechanical energy treatment so as to be 1 or less. Also, the interlayer distance (d
002) is 0.34 nm or less, the crystallite size (Lc) is 30 nm or more, and the true density is 2.25 g / cc or more.

The treated graphite particles have a median diameter of 5 to 50 μm and a BET specific surface area of 25 m
² / g or less. Also,
Carbonaceous or graphitic particles that had been subjected to mechanical energy treatment so that the apparent density ratio before and after treatment was 1.1 or more and the median diameter ratio before and after treatment was 1 or less were mixed with an organic compound serving as a carbon precursor. The method is characterized in that a multi-layer structure carbon material obtained by carbonizing the organic compound is used later.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The carbonaceous or graphitic particles in the present invention are carbonaceous powders that are natural or artificial graphite particles or graphite precursors. The carbonaceous and graphitic powders before these treatments have an interlayer distance (d002) of 0.340 nm or less and a crystallite size (L
c) is preferably 30 nm or more, and the true density is 2.25 g / cc or more. Further, the interlayer distance (d002) is set to 0.
337 nm or less is more preferable, and 0.336 nm or less is most preferable. Crystallite size (Lc) is 50 nm
The above is more preferable, and the one with 100 nm or more is most preferable. The crystallinity of carbonaceous or graphitic particles is
The carbonaceous or graphitic particles used in the present invention, which can also be determined by electrochemical capacity using lithium ions, have a charge / discharge rate of 0.2 mA / cm ² , and have a half-cell capacity, It is preferably at least 330 mAh / g, more preferably at least 350 mAh / g. That is, a highly crystalline carbon material having a carbon hexagonal network structure developed to some extent. When metal ions are intercalated, the composition is expressed as C ₆ Li, and accommodates 1 atom of lithium for 6 atoms of carbon. It is particularly preferred that the material be capable of forming the stage 1 structure.

When the crystallinity of the carbonaceous or graphitic particles before the treatment is not so high, a heat treatment for increasing the crystallinity can be performed again after the mechanical energy treatment. When mechanical energy treatment is performed in a state where crystallinity is low, plane orientation is not advanced to a high degree, and disorder is remaining in the structure, the crushed surface is relatively isotropic due to its structure, and it is rounded It becomes easier to obtain processed products.

The highly crystalline carbon material having a developed carbon hexagonal network structure includes a highly oriented graphite in which hexagonal mesh planes are largely grown in a plane orientation, and an isotropic material in which highly oriented graphite particles are aggregated in the same direction. High-density graphite. As highly oriented graphite,
Natural graphite produced from Sri Lanka or Madakascal, so-called quiche graphite precipitated as supersaturated carbon from molten iron, and artificial graphite having a high degree of graphitization are preferably used.

[0014] Natural graphite is described in a book published in 1974 from the Industrial Technology Center Co., Ltd., in the section on graphite in "Pulverized Particle Process Technology", and in "HAND" published by Noyes Publications.
According to “BOOKOF CARBON, GRAPHITE, DIAMOND AND FULLERENES”, depending on its properties, flake graphite (Flake Glaphi
te), scaly graphite (Crystalline (Vein) Glaphite) and soil graphite (Amorphousu Glaphite). The degree of graphitization is
Scaly graphite is the highest at 100%, followed by 9% of scaly graphite.
9.9% and soil graphite is as low as 28%. The quality of natural graphite is determined by the major production areas and veins, and flaky graphite (FlakeGlaphite) is produced in Madagascar, China, Brazil, Ukraine, Canada, etc., and flaky graphite (Crysta
lline (Vein) Glaphite) mainly comes from Sri Lanka.
Soil graphite is mainly produced in the Korean Peninsula, China, Mexico, etc. Among these natural graphites, those that are finally used as fillers in the present invention include soil graphite, which generally has a small particle size and a low purity. Is preferably selected from flaky graphite and flaky graphite.

[0015] Artificial graphite is produced by heating petroleum coke or coal pitch coke at a temperature of 1500 to 3000 ° C in a non-oxidizing atmosphere. Any material that exhibits high electrochemical capacity can be used. As the size of the particles before the treatment, the median diameter is 10 μm or more,
It is preferably at least 15 μm, more preferably at least 20 μm, even more preferably at least 30 μm.

Although there is no particular upper limit on the size of the particles before the treatment, the median diameter is preferably 1 mm or less, more preferably 500 μm or less, still more preferably 250 μm or less.
Particularly preferably, it is 200 μm or less. 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. As an index for quantitatively discussing the filling structure, an apparent density or a filling ratio is used. The apparent density indicates the mass per unit filling volume, and is also called bulk density.

Apparent density = mass of filled powder / filled volume of powder In the present invention, mechanical energy treatment is performed so that the apparent density ratio before and after treatment is 1.1 or more and the median diameter ratio before and after treatment is 1 or less. I do. As described above, the improvement of the filling property of the carbonaceous or graphitic particles by adding the mechanical energy is considered to be due to the fact that the carbonaceous or graphitic particles having a high filling property are introduced with roundness in the particle shape. Because.

In the present invention, the apparent density ratio before and after the treatment is the tap density ratio before and after the treatment, where the tap density before the treatment is the denominator and the tap density after the treatment is the numerator. Various expressions have been proposed as expressions representing tap filling behavior. As an example, the following equation: ρ−ρ _{n =} A · ex
p (−kn) can be mentioned. Here, ρ is the apparent density at the end of filling, ρn is the apparent density at the time of filling n times, and k and A are constants. The apparent density (tap density) of the present invention is the apparent density (ρ ₁₀₀₀ ) at the time of filling the 20 cc cell 1000 times with taps, and the final apparent density ρ.
Refers to what is considered.

The median diameter ratio before and after the treatment is defined as the median diameter of the volume-based particle size distribution using the median diameter before the treatment as a denominator and the median diameter after the treatment as a numerator, as measured by a laser type particle size distribution analyzer. It is a diameter ratio. The measurement principle of the laser type particle size measurement is that particles having anisotropic shape are averaged isotropically, and a particle size distribution substantially converted into a sphere can be obtained.

It is known that in order to enhance the filling property of powder particles, it is better to fill smaller particles so as to inscribe the voids formed between the particles. Therefore, it is conceivable to reduce the particle size by performing a treatment such as pulverization on the carbonaceous or graphitic particles, but probably because of the crystal structure of the carbonaceous or graphitic particles or the carbonaceous powder after the pulverization treatment. Fillability is reduced. 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. In other words, factors that affect the filling factor are the particle size ratio and the composition ratio, that is, the particle size distribution is important.

However, these studies were performed on a group of model spherical particles, and the carbonaceous or graphitic particles before treatment handled in the present invention were flake-like, scale-like, plate-like, Even if an attempt is made to increase the filling rate by simply controlling the particle size distribution only by classification or the like, it is not possible to produce such a high filling state. In general, if the particle size distribution shifts toward the small particle size as a whole, it can be expected that the coordination number increases, the porosity decreases, and as a result, the packing property improves. However, real scales, scales,
When the relationship between the particle size and the filling property of the plate-like carbonaceous or graphitic particles is arranged, the filling property tends to deteriorate as the particle diameter decreases. That is, the smaller the particle size, the lower the filling property. In other words, the coordination number did not increase as expected. This is because fine particles in the form of protrusions, which can be called `` saddle '', `` peeling off '', and `` bending '', are connected to the surface of the carbonaceous or graphitic particles with a certain degree of strength, and these are connected to adjacent particles. It is considered that the number of contact points of the above has been significantly reduced.

According to the study of the present inventors, it is found that the apparent density (tap density) of a carbon or graphite particle having a substantially equal true density and a substantially equal median diameter is higher as the shape is spherical. Has been confirmed. That is,
It is important that the shape of the particles be rounded and close to spherical. If the particle shape approaches a spherical shape, the filling property of the powder is also greatly improved. In the shape analysis, SEM observation in the state of the particles or the cross section of the molded body, images of thousands of particles dispersed in the liquid were taken one by one using a CCD camera, and the average shape parameters were obtained. Flow type particle image analysis that can be calculated, sedimentation velocity in liquid, BE
The T specific surface area, the sphere-converted specific surface area calculated from the particle size distribution, the ratio of both specific surface areas, and the like were used.

In the present invention, for the above reasons, the apparent 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. The apparent density ratio before and after the treatment is 1.1 or more, preferably 1.3 or more, more preferably 1.4 or more, and still more preferably 1.7 or more.

The apparent density after the treatment is 0.5 g / cc.
The value is preferably not less than 2.0 and not more than 2.0, but the preferable value varies depending on the median diameter. Assuming that the median diameter is B μm, when B is 40 or less, the measured apparent density is preferably larger than the A value with respect to the A value defined by the following equation.

A = −0.012 + 3.29 × 10 ⁻² × B
When −5.41 × 10 ⁻⁴ × B ² B is 40 or more, the apparent density is 0.6 g / cc.
The above are preferred. In particular, in the entire median diameter region, it is more preferably 0.65 g / cc or more,
It is particularly preferred that it be 0.7 g / cc or more. The apparent density here has a slightly different absolute value depending on the measurement method, but is obtained by the tap method and is based on Kawakita's formula.

In the present invention, the mechanical energy treatment is to reduce the particle size so that the median diameter ratio of the powder particles before and after the treatment becomes 1 or less and to control the shape at the same time. Among the engineering unit operations that can be used for particle design such as mixing, granulation, surface modification, and reaction, the operations belong to the pulverization process. Grinding 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 process is classified according to the type of force applied to the substance and the processing mode. Here, the types of forces are a smashing force (impact force), a crushing force (compression force), a crushing force (milling force), and a shaving force (shearing force).
It is roughly divided into four. On the other hand, treatment forms are 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. Pulverization is a treatment in which the types of forces applied to these objects to be crushed and the processing forms are combined in various ratios.

In order to carry out the pulverization, a chemical reaction such as blasting or volume expansion may be used. However, it is usually general to use a mechanical device such as a pulverizer. These pulverization processes classified according to a combination of a method of applying a force and a processing mode are properly used according to the purpose of the process. The pulverization treatment used in the present invention is preferably a treatment in which the proportion of the surface treatment is finally high, regardless of the presence or absence of volume pulverization during the pulverization. In other words, in the initial stage of the pulverization process, the median diameter decreases, but after that stage has progressed to some extent, the rate of change in the particle diameter decreases, and conversely, the surface pulverization proceeds, and from the surface of the workpiece, A process in which the pulverization proceeds so that the corner can be removed is preferable. Alternatively, a process is preferred in which weak surface pulverization proceeds, the particle shape changes while the particle size remains substantially constant, and a rounded powder is obtained.

According to the study of the present inventors, when volume pulverization is actively performed, the filling property is not improved, and the particle shape is only reduced in particle size, and no large change in shape can be observed. Was. This is presumably because the carbonaceous or graphitic particles used in the present invention have a flaky, scaly, or plate-like form. Industrially available graphite materials are polycrystalline. However, the microcrystals in the material are likely to be aligned in a specific direction and therefore have considerable anisotropy in various properties. The mechanical strength is also one of the properties in which anisotropy appears, and carbonaceous or graphitic particles having a flake-like, scale-like, or plate-like morphology have a property of being easily cleaved parallel to the bottom surface. Therefore, in the process of actively performing volume pulverization, in order to reduce the particle diameter while accompanied by cleavage,
It is difficult to introduce roundness into the particle shape.

The median diameter ratio before and after the treatment is preferably 1 or less. When granulation occurs, the median diameter ratio becomes 1 or more, and the apparent density also increases. But,
It is fully expected that the granulated powder will return to the original state before the treatment in the final molding process, which is not preferable. In order to remove the corners of carbonaceous or graphitic particles and introduce roundness into the particle shape, it is important that surface grinding is performed. It is important to determine the grinding capacity. The former is to select the type of device according to the type of crushing force applied to the object to be crushed, and the latter is to utilize the limit of crushing force (crushing limit) that exists for each device model.

Regarding the selection of the type of the device, it has been clarified by the inventors that the type of the device in which the pulverization proceeds by the shearing force is effective. As a device for advancing the surface pulverization, first, a device using a pulverizing medium such as a ball mill, a vibration mill, and a medium stirring mill is preferable. In these models, it is considered that the grinding is performed at the center of the grinding force and the shearing force, so that the corner can be ground. Wet grinding is also preferred, as is dry grinding. Examples of specific device names include a vibration mill and a ball mill manufactured by Chuo Kakoki Co., Ltd., a mechano mill manufactured by Okada Seiko Co., Ltd., and a dry / wet type manufactured by Kurimoto Iron Works Co., Ltd. And a medium stirring mill. Next, as a device capable of performing surface pulverization, as a processed material passes between a rotating container and a taper attached to the inside of the container, a compressive force caused by a speed difference between the rotating container and the taper is generated. A model in which a shear force is applied to the processed material is preferred. These devices are originally devices for compounding two or more kinds of powders and performing surface modification of the powders. However, since they are devices to which a shear force is strongly applied, the filling property of the powders is high. It is considered that the particles could be improved, that is, the particles could be rounded. As an example of specific equipment names, Theta Composer manufactured by Tokuju Kosakusho Co., Ltd., Hosokawa Micron Corporation
And a mechanofusion system manufactured by the company.

The pulverization limit refers to a region of a particle diameter, and is a lowermost limit region as a particle diameter at which volume pulverization proceeds. That is, it is a particle diameter region where the particle diameter is reduced, the collision probability is reduced, and the particle's own weight is also reduced, so that a large stress is not generated even when the particles collide, and the volume pulverization does not progress. In this region, the surface pulverization is performed instead of the volume pulverization, and the filling property of the powder after the treatment improves only the filling property without largely changing the median diameter. To utilize this pulverization limit, a single pulverization process can be performed, but it is preferable that the pulverized material that has passed through the processing device is again fed into the processing device. Further, a device having a built-in classification mechanism is also preferable. It is more preferable to connect the classifying mechanism to the pulverization processing apparatus and circulate the processed material, since the pulverization is performed a plurality of times. The number of repetitions is 1
Or more times, more preferably 3 times or more, particularly preferably 4 times or more. A high-speed rotary mill is essentially a mechanical pulverizer that performs volume pulverization by combining impact force, compression force, and shear force. Preferred apparatus conditions are conditions that suppress the impact force and increase the shearing force, but by repeating the processing, the particle diameter region of the processed product reaches the apparatus-specific pulverization limit, and surface pulverization is mainly performed. become. Alternatively, the same effect can be reliably obtained even when the processing is performed for a long time using a batch-type processing apparatus, and this is further preferable.

As a result of diligent studies, the present inventors can proceed with surface pulverization even with a processing apparatus designed to promote volume pulverization as long as the pulverization limit is utilized. It has been found that it is possible to obtain treated products with improved filling properties. As such a process, it is preferable to use a high-speed rotary mill composed of a rotor that rotates at a high speed and a stator provided around the rotor. It is more preferable to operate the rotor at a low rotation speed so that a large impact force is not applied. Further, it is preferable that a plate-shaped blade is attached to the rotor for use, and a certain gap or more is provided in the gap between the rotor and the stator so that impact pulverization hardly occurs. As an example of a specific device name, a fine mill manufactured by Nippon Pneumatic Industries Co., Ltd., a turbo mill manufactured by Turbo Kogyo Co., Ltd., or the like may be used.

However, if the concept of the pulverization limit is used, the surface pulverization progresses, and a processed product having rounded corners and improved filling properties cannot be obtained with any type of apparatus. According to the Graphite section of the “Granular Particle Process Technology Collection” published by the Industrial Technology Center in 1974, graphite can easily be flattened if it is processed by a friction pulverization type. It is described that if energy-type pulverization is performed, friction between particles may increase, or particles having rounded shapes with sharp corners may be obtained. However, as a result of studies by the inventors, a fluid energy type pulverizer could not obtain a powder having enhanced filling properties in a target particle diameter range of 10 to 50 μm. This is considered to be because the pulverizing power was too strong because the fluid energy type pulverizer employs the principle of pulverizing particles in a gas stream close to the speed of sound.

As a result of further studies by the present inventors, a mixing device having a specific structure is suitable as a surface pulverizing device as a device capable of continuously applying a shearing force to an object to be processed. I found something. As a mixing device having a specific structure, a processing chamber in which a plurality of plow-shaped or saw-tooth-shaped paddles fixed to the shaft and a plurality of puddles are arranged in different phases is provided. The wall is formed in a cylindrical shape along the outermost line of rotation of the paddle to minimize the gap, multiple paddles are arranged in the axial direction of the shaft, and the screw type disintegrator that rotates at high speed on the inner wall of the device A mixing device having a structure in which one or a plurality of crushing blades are provided in one or more stages can be given. The workpiece is subjected to a shearing force by the screw type crusher and, at the same time, receives a compressive force to the wall surface by the rotation of the paddle. The structure that applies the shearing force and the compressive force has a structure that matches the surface crushing mechanism that the present inventors consider preferable, despite being originally a mixer. As an example of a specific device name, a Reedige mixer manufactured by Matsuzaka Giken Co., Ltd., a Plowshare mixer manufactured by Taiheiyo Kiko Co., Ltd., and the like are exemplified.

When the true density of the carbonaceous powder before the treatment is less than 2.25 and the crystallinity is not so high, it is preferable to perform a heat treatment for increasing the crystallinity again after the above-mentioned mechanical energy treatment. Heat treatment is preferably 2000 ° C or higher,
More preferably 2500 ° C. or higher, most preferably 280 ° C.
It is better to carry out at 0 ° C. or higher. The median diameter of the carbonaceous or graphitic particles after the treatment of the present invention is 5 to 50 μm, preferably 10 to 50 μm, and more preferably 10 to 35 μm.
m, particularly preferably in the range of 15 to 25 μm.
The amount of fine powder of 10 μm or less is 25% by volume-based particle size distribution.
%, Preferably 17% or less, more preferably 14% or less, even more preferably 12% or less.
The BET specific surface area of the graphite particles after the treatment is 0.5 m ²
/ G or more and 25.0 m ² / g or less, preferably 2.
0 m ² / g or more and 10.0 m ² / g or less, more preferably 3.0 m ² / g or more and 7.0 m ² / g or less, still more preferably 3.5 m ² / g or more and 5.0 m ² / g or less. . As a method of achieving both the particle diameter and the BET specific surface area, there is a control of the specific surface area by a classification operation. By performing the fine powder removal by the classification operation, the specific surface area can be effectively reduced. Further, in a Raman spectrum analysis using an argon ion laser beam, the peak PA (peak intensity IA) and 1350 to 1
In the range of 370 cm ^-1 , the intensity ratio R = IB / IA of the peak PB (peak intensity IB) is 0.0 or more and 0.5 or less and 158.
The half width of the peak in the range of 0 to 1620 cm-1 is 26 cm.
It is preferably -1 or less. Further, the intensity ratio R of the Raman spectrum is more preferably 0.4 or less, most preferably 0.3 or less. Half width is more preferably 25 cm-1 or less of the peak in the range of 1580~1620cm ^-1, 24cm ^-1
The following are most preferred. In addition, the average circularity for all particles (the ratio of the perimeter of a circle corresponding to the particle area as a numerator and the perimeter of the captured particle projection image as a denominator is 1 as the particle image is closer to a perfect circle, The smaller the particle image is, the smaller the value is when the particle image is elongated or uneven) is preferably 0.940 or more. Further, based on the particle size distribution based on the circle equivalent diameter, a 15 μm limited average circularity of 0.85, which is limited to target only particles having a median diameter of 15 μm or more, is 0.85.
What is 0 or more is more preferable. The equivalent circle 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 carbon material having a multilayer structure in the present invention is obtained by mixing the carbonaceous or graphitic particles after the treatment with an organic compound to be carbonized in a firing step, and then firing the organic compound. As organic compounds to be mixed with carbonaceous or graphitic particles, first, as organic substances that progress carbonization in the liquid phase, coal tar pitch from soft pitch to hard pitch, coal-based heavy oil such as coal liquefied oil, asphaltene Ethylene tar pitch obtained by heat-treating petroleum heavy oils such as naphtha tar and other cracked heavy oils that are by-produced during thermal cracking of direct current heavy oils such as naphtha and naphtha, and cracked heavy oils , FCC decant oil, heat-treated pitch such as Ashland pitch and the like can be used. Further, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl alcohol and other vinyl polymers and 3-methylphenol formaldehyde resin,
Substituted phenolic resins such as 3,5-dimethylphenol formaldehyde resin; aromatic hydrocarbons such as acenaphthylene, decacyclene and anthracene; nitrogen ring compounds such as phenazine and acridine; and sulfur ring compounds such as thiophene. Examples of the organic substance that progresses 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, furfuryl alcohol resin, and phenol-formaldehyde. Examples thereof include thermosetting resins such as resins and imide resins, and thermosetting resin raw materials such as furfuryl alcohol. These organic substances can be used by adhering to the surface of the powder particles by appropriately dissolving and diluting the organic substance by selecting a solvent as necessary.

In the present invention, usually, a mixture of such carbonaceous or graphitic particles and an organic compound is heated to obtain an intermediate substance, which is then carbonized, fired and pulverized, so that the surface of the powdery particles is finally obtained. A carbonaceous powder having a multilayer structure in which the surface layer of the carbonaceous material is formed is obtained. The proportion of the carbonaceous material derived from the organic compound in the carbonaceous powder having the multilayer structure is 50% by weight.
0.1 wt% or less, preferably 25 wt% or less.
5% by weight or more, more preferably 15% by weight or less 1% by weight
As described above, the content is particularly preferably adjusted to 10% by weight or less and 2% by weight or more.

On the other hand, the production process for obtaining such a multi-layer carbonaceous material according to the present invention is divided into the following four processes. First step: a step of mixing a carbonaceous or graphitic particle and an organic compound with a solvent, if necessary, using various commercially available mixers and kneaders to obtain a mixture. Second step: a step of heating the mixture while stirring, if 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 ° C. or more and 3000 ° C. or less in an atmosphere of an inert gas such as a nitrogen gas, a carbon dioxide gas and an argon gas, or a non-oxidizing atmosphere to obtain a carbonized material. .

Fourth step: a step of subjecting the carbonized substance to powder processing such as pulverization, crushing, and classification as required. Among these steps, the second step and the fourth step
The step can be omitted in some cases, and the fourth step is the third step.
It may be performed before the process.

The heat treatment conditions in the third step include:
Thermal history temperature conditions are important. The lower limit of the temperature is slightly different depending on the kind of the organic compound and its heat history, but it is usually 50.
0 ° C. or higher, preferably 700 ° C. or higher, more preferably 9 ° C.
It is 00 ° C or higher. On the other hand, the upper limit temperature can be raised to a temperature that does not basically have a structural order exceeding the crystal structure of the carbonaceous or graphitic particles. Therefore, the upper limit temperature of the heat treatment is usually 3000 ° C. or less, preferably 2800 ° C.
C. or lower, more preferably 2500 C. or lower, particularly preferably 1500 C. or lower. Under such heat treatment conditions, the rate of temperature rise, 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 reactor used in this step may be a batch type or a continuous type,
One or more groups may be used.

The multilayer carbon material of the present invention has a volume-based
A dian diameter of 5 to 70 μm, preferably 10 to 40 μm,
Particularly preferably, it is 15 to 30 μm. According to the present invention
Specific surface of multi-layered carbon material measured using BET method
The product is preferably 1 to 10 m^Two/ G, more preferably 1 to
4m^Two/ G, particularly preferably 1-3 m^Two/ G range
Preferably, the carbonaceous material having a multilayer structure of the present invention
Has a wavelength of 5145 cm^-1Argon ion laser light
Raman spectrum analysis using CuKα radiation as the source
In the diffractogram of X-ray wide-angle diffraction, carbon
Does not exceed the crystallinity of the graphitic particles.
 The spectra and peaks are as follows unless otherwise specified.
It is a Raman spectrum according to conditions. That is, 158
0-1620cm^-1PA (peak intensity I
A) and 1350-1370 cm ^-1Peak P in the range
B (peak intensity IB). As specific numbers,
Preferably 0.01 or more, 1.0 or less, more preferably
0.05 or more, 0.8 or less, more preferably 0.1 or less
Above, it is 0.6 or less. Also, the apparent density is
More improved than the more used nuclear graphite material, but 0.7
It is desirable to control to a range of -1.2 g / cc. all
The average circularity for particles was 0.94 before the multilayer structure was formed.
Those which are larger than 0 are preferred. Furthermore, the circle equivalent diameter
Particles having a median diameter of 15 μm or more
15μm limited average with restriction to target only
The degree of circularity is also greater than 0.850 before the multilayer structure
Is more preferred. Multi-layer structuring is the core dynamic energy
Further improve the apparent density of the processed material
This has the effect of introducing further roundness into the shape.

The electrode for a non-aqueous secondary battery of the present invention is prepared by adding a binder, a solvent and the like to the treated carbonaceous or graphitic particles to form a slurry, and forming a metal current collector such as a copper foil. The slurry is applied to the substrate and dried to form an electrode. Further, the electrode material can be directly formed into an electrode shape by a method such as roll molding or compression molding. Examples of the binder that can be used for the above-mentioned purposes include, but are not limited to, solvents, polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, resin polymers such as cellulose, styrene / butadiene rubber, isoprene rubber, butadiene rubber, and ethylene.・ Rubber-like polymer such as propylene rubber, styrene / butadiene / styrene block copolymer, hydrogenated product thereof, styrene / ethylene / butadiene / styrene copolymer, styrene / isoprene / styrene block copolymer, hydrogenated Elastomer-like polymers such as products, soft resin-like polymers such as syndiotactic 12-polybutadiene, ethylene-vinyl acetate copolymer, propylene-a-olefin (C2-12) copolymer, polyfluorinated Vinylidene, polytetrafluoroethylene, polythene Fluorine polymers such as La-ethylene copolymer, an alkali metal ion, the polymeric composition may be mentioned in particular has an ionic conductivity of lithium ions. Examples of the polymer having ion conductivity include polyether-based polymer compounds such as polyethylene oxide and polypropylene oxide, crosslinked polymers of polyether compounds, polyepichlorohydrin, polyphosphazene, polysiloxane, polyvinylpyrrolidone, and polyvinylidene carbonate. , A polymer compound such as polyacrylonitrile, and a complex of lithium salt, or an alkali metal salt mainly composed of lithium, or an organic compound having a high dielectric constant such as propylene carbonate, ethylene carbonate, g-butyrolactone And a low viscosity organic compound such as a linear carbonate. The ionic conductivity of such an ionic conductive polymer composition at room temperature is preferably 10 ⁻⁵ S / cm or more, more preferably 10 ⁻³ S / cm.
/ Cm or more.

The carbonaceous material used in the present invention and the above-mentioned binder may be mixed in various forms.
That is, 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 binder layer is attached to the surface of the carbonaceous material particles are exemplified. The mixing ratio of the carbonaceous material and the binder is preferably 0.1 to 30% by weight, more preferably 0.5 to 10% by weight, based on the carbonaceous material. If the binder is added in an amount larger than this, the internal resistance of the electrode increases, which is not preferable. If the amount is smaller than this, the binding property between the current collector and the carbonaceous powder is poor.

At this time, by setting the density of the active material layer on the electrode formed by a method such as roll forming or compression forming (hereinafter referred to as electrode density) to be larger than 1.2 and 1.6 or less,
More preferably, when the ratio is 1.3 or more and 1.5 or less, the capacity per unit volume of the battery can be maximized without impairing high-efficiency discharge and low-temperature characteristics.
A battery formed by combining the negative electrode prepared in this manner with a metal chalcogenide-based positive electrode for a lithium ion battery and an organic electrolyte mainly containing a carbonate-based solvent has a large capacity and is irreversible observed in the initial cycle. The battery has a small capacity, high storage stability and high reliability of the battery when left at high temperatures, and extremely excellent high-efficiency discharge characteristics and low-temperature discharge characteristics. However, there are no restrictions on the selection of members necessary for the battery configuration such as the positive electrode and the electrolyte.

[0046]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention. (Measurement method) (1) Volume-based average particle size About 1 cc of a 2 vol% aqueous solution of polyoxyethylene (20) sorbitan monolaurate was used as a surfactant, and this was mixed with carbonaceous powder in advance, and then ion-exchanged water was used. Was used as a dispersion medium, and the volume-based average particle diameter (median diameter) was measured with a laser diffraction particle size distribution analyzer “LA-700” manufactured by Horiba, Ltd.

(2) Apparent Density (Tap Density) A powder density measuring device “Tap Denser KYT-3000” manufactured by Seishin Enterprise Co., Ltd. was used. The powder was dropped into a 20 cc tapping cell, and after the cell was completely filled, tapping with a stroke length of 10 mm was performed 1,000 times, and the apparent density at that time was measured. (3) Measurement of BET specific surface area Using AMS-8000 manufactured by Okura Riken Co., Ltd., it was heated to 350 ° C. as preliminary drying, nitrogen gas was flowed for 15 minutes, and then measured by the BET one-point method by nitrogen gas adsorption.

(4) Measurement of True Density Using a 0.1% aqueous solution of a surfactant, the true density was measured by a liquid phase replacement method using a pycnometer. (5) X-ray diffraction X-ray standard high-purity silicon powder of about 15% is added to and mixed with the sample, packed in a sample cell, and a CuKα ray monochromatized with a graphite monochromator is used as a radiation source, and a reflection type diffract is used. The wide-angle X-ray diffraction curve was measured by a meter method, and the interlayer distance (d002) and the crystallite size (Lc) were determined by the Gakushin method.

(6) Raman Measurement Using NR-1800 manufactured by JASCO Corporation, wavelength: 514.5 n
In Raman spectrum analysis using an argon ion laser beam of m, the intensity of the peak PA around the 1580 cm ^-1 IA, the intensity of the peak PB in the range of 1360 cm ^-1 I
B is measured, and the ratio of its intensities R = IB / IA and 1580c
The half width of the peak near m ^-1 was measured. In preparing the sample, the cell was filled in a powder state by natural fall, and the measurement was performed by rotating the cell in a plane perpendicular to the laser light while irradiating the sample surface in the cell with the laser light.

(7) Measurement of circularity Flow particle image analyzer “FPIA-” manufactured by Toa Medical Electronics Co., Ltd.
Using "1000", the particle size distribution was measured by the equivalent circle diameter and the circularity was calculated. Ion exchange water is used as the dispersion medium, and polyoxyethylene (20) is used as the surfactant.
Sorbitan monolaurate was used. First, after calculating the average circularity for all the particles, based on the particle size distribution based on the equivalent circle diameter, a restriction is applied so that only particles having a median diameter of 15 μm or more are targeted, and the 15 μm limited average circularity is calculated. Was. The equivalent circle diameter is the diameter of a circle (equivalent circle) having the same projected area as the captured particle image, and the circularity is defined as the circumference of the equivalent circle as a numerator and the periphery of the captured particle projection image. This is the ratio with the length as the denominator.

(8) Measurement of Electric Capacity by Half-Battery 8-1) Preparation of Half-Battery Polyvinylidene fluoride (PVd) was added to 5 g of an electrode material sample.
A solution obtained by adding 10% by weight of a dimethylacetamide solution of F) in terms of solid content 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. Furthermore, after pressure bonding was performed so that the electrode plate density was about 1.3 g / cc, it was punched into a disk having a diameter of 15.4 mm, and dried at 110 ° C. under reduced pressure to obtain an electrode. Thereafter, a coin cell in which the electrode and the lithium metal electrode face each other around the separator impregnated with the electrolytic solution,
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 1: 1 was used.

8-2) Measurement of Electric Capacity In the charge / discharge test, the current value at the low charge / discharge rate was set to 0.2 mA, and the current value at the high charge / discharge rate was set to 7 mA, and the charge was performed until the potential difference between both electrodes became 0 V. And discharge was performed until the voltage reached 1.5 V. The discharge capacity at the fifth cycle was used as the electric capacity for comparing the degree of crystallinity of the carbonaceous material. The ratio of the capacity at 0.2 mA as a denominator and the capacity at 0.7 mA as a numerator was used as an index of rapid charge / discharge properties. An unpressed electrode plate was used for comparison of crystallinity, and an electrode plate after press treatment was used for evaluation after mechanical energy treatment.

(Selection of raw materials before treatment) Raw materials before pulverization were selected by X-ray diffraction measurement, Raman spectroscopy, and electrochemical capacity. As a result, petroleum artificial graphite 2 with different particle size
Two kinds of natural graphite made from Sri Lanka with different species and particle sizes were selected. Table 1 lists the raw materials used in the study.

(Mechanical energy treatment) 1) Example 1 Using a research pot mill manufactured by Chuo Kakoki Co., Ltd.
A stainless steel ball having a diameter of 5 mm and a natural graphite powder A of 0.5 kg were charged into a 3.6-liter cylindrical grinding pot, and grinding treatment was performed at 80 rpm for 24 hours. Tables 2 and 3 show the results. 2) Example 2 Using a φ200 batch dry agitating mill manufactured by Kurimoto Ironworks Co., Ltd., crushing media of 2 mm diameter alumina balls and artificial graphite powder B (0.3 kg) were charged, and 480 r
The crushing treatment was performed at pm for 25 minutes. The ratio R value of Raman spectrum intensity half width of the peak around the 0.19,1580Cm ^-1 was 22.2cm ^-1. Other results are shown in Tables 2 and 3.

3) Example 3 T-400 type turbo mill (4J) manufactured by Turbo Kogyo Co., Ltd.
), Rotate the rotor at 3600 rpm,
The processed material was supplied at 150 kg / hr by a screw feeder and pulverized. The particle size of the collected pulverized material did not change significantly. In order to perform surface pulverization using the pulverization limit, the pulverized material was re-pulverized. The same processed material was processed a total of four times. Tables 2 and 3 show the results.
Shown in

4) Example 4 A natural graphite powder B of 4.0 k was prepared using a M20 type Reigeger mixer (20 liters in volume) manufactured by Matsubo Co., Ltd.
g, a paddle for stirring was rotated at 230 rpm, and a chopper for crushing was rotated at 3000 rpm, and the mixture was stirred for 150 minutes. The ratio R value of Raman spectrum intensity is 0.22, 15
The half-value width of the peak in the vicinity of 80 cm ^-1 was 21.3 cm ^-1. Other results are shown in Tables 2 and 3. 5) Example 5 Using an FKM-130D type Reedige mixer (manufactured by Matsubo Co., Ltd.) (volume of 130 liters), 50 kg of artificial graphite powder B was charged, and a paddle for stirring was set at 140 rpm.
Rotate the chopper for crushing at 3600 rpm, 30
Stirred for minutes. Raman spectrum intensity ratio R value is 0.2
The half width of the peak near 5, 1580 cm ^-1 is 21.8.
cm ^-1 . Other results are shown in Tables 2 and 3.

6) Example 6 The same apparatus conditions as in Example 5 were used and the raw materials were stirred for 60 minutes. Conclusion
Tables 2 and 3 show the results. 7) Example 7 The mixture was stirred for 150 minutes under the same apparatus conditions and raw materials as in Example 5.
Raman spectrum intensity ratio R value is 0.29, 1580c
m^-1Of the peak near is 22.4 cm ^-1So
Was. Other results are shown in Tables 2 and 3. 8) Example 8 The same equipment conditions and raw materials as in Example 5 were used to obtain Example 3.
The treatment was stirred for 90 minutes. Tables 2 and 3 show the results.
You.

9) Example 9 Using an AM-80F type mechanofusion system manufactured by Hosokawa Micron Co., Ltd. (having a grinding chamber diameter of 800 mm), 7 kg of artificial graphite powder A was charged, and the grinding chamber was rotated at 500 rpm.
m and run for 30 minutes. The ratio R value of Raman spectrum intensity half width of the peak around the 0.35,1580Cm ^-1 was 23.5cm ^-1. Other results are shown in Tables 2 and 3. 10) Example 10 Using an AM-80F mechanofusion system manufactured by Hosokawa Micron Co., Ltd. (diameter of grinding chamber: 800 mm), 7 kg of artificial graphite powder A was charged, and the grinding chamber was rotated at 500 rpm.
m and run for 30 minutes. The ratio R value of Raman spectrum intensity half width of the peak around the 0.27,1580Cm ^-1 was 22.3cm ^-1. Other results are shown in Tables 2 and 3.

11) Example 11 30 g of artificial graphite powder B and 1 kg of ceramic balls having a diameter of 0.5 mm were charged using an AM-20FS mechanofusion system manufactured by Hosokawa Micron Corp. (diameter of a grinding chamber of 200 mm). The grinding chamber was rotated at 450 rpm and operated for 30 minutes. Raman spectrum intensity ratio R
Value half width of a peak in the vicinity of 0.49,1580Cm ^-1 was 25.8cm ^-1. Other results are shown in Tables 2 and 3. 12) Example 12 Theta Composer (manufactured by Tokuju Corporation)
0L), 10 kg of artificial graphite B was charged, the vessel was rotated at 20 rpm, the rotor was rotated at 400 rpm, and the apparatus was operated for 30 minutes. Tables 2 and 3 show the results.

13) Example 13 4 kg of the treated product obtained in Example 2 and 1 kg of petroleum-based tar
Were mixed in a batch kneader having a sigma type blade. Subsequently, the temperature was raised to 700 ° C. in a nitrogen atmosphere,
A tar removal treatment was performed, followed by a heat treatment to 1200 ° 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, thereby finally obtaining carbonaceous material particles having a multilayer structure. Tables 4 and 5 show the results. 14) Example 14 The same treatment as in Example 13 was performed using the processed product obtained in Example 3. Tables 4 and 5 show the results.

15) Example 15 The same treatment as in Example 13 was performed using the processed product obtained in Example 4. Tables 4 and 5 show the results. 16) Example 16 3 kg of the treated product obtained in Example 5 and 7 kg of petroleum tar
Were mixed in a batch kneader having a sigma type blade. Subsequently, the temperature was raised to 700 ° C. in a nitrogen atmosphere,
A tar removal treatment was performed, followed by a heat treatment to 1200 ° 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, thereby finally obtaining carbonaceous material particles having a multilayer structure. Tables 4 and 5 show the results.

17) Comparative Example 1 KTM0Z type Kryptron manufactured by Kawasaki Heavy Industries, Ltd. was used, artificial graphite powder A was supplied at 17 kg / hr, and the rotor was rotated at 9000 rpm for operation. Table 2 shows the results
And Table 3 below. 18) Comparative Example 2 Using an FM-300S type fine mill manufactured by Nippon Pneumatic Industries, artificial graphite powder A was supplied at 40 kg / hr, and the rotor was rotated at 3000 rpm for operation.
Tables 2 and 3 show the results.

19) Comparative Example 3 T-400 type turbo mill (4J) manufactured by Turbo Kogyo Co., Ltd.
), Rotate the rotor at 3600 rpm,
The processed material was supplied at 150 kg / hr by a screw feeder and pulverized. Tables 2 and 3 show the results. 20) Comparative Example 4 Using an ACM Pulperizer Model 10 manufactured by Hosokawa Micron Corporation, artificial graphite powder B was supplied at 50 kg / hr, and the pulverizing blade was rotated at 7000 rpm to perform the treatment. Tables 2 and 3 show the results.

21) Comparative Example 5 INM-30 Inomaizer manufactured by Hosokawa Micron Corporation
And supply artificial graphite powder B at 190 kg / hr
Then, the grinding blade is rotated at 5000 rpm to perform the processing.
Was. Tables 2 and 3 show the results. 22) Comparative Example 6 Nippon Pneumatic Industries, Inc. IDS-2UR Type Impact Plate Type
30kg / hr of artificial graphite powder B using jet mill
And pulverized. Raman spectrum intensity ratio R
The value is 0.81, 1580 cm^-1Half width of the peak near
Is 28.2cm ^-1Met. Table 2 and Table 2 show other results
3 is shown. 23) Comparative Example 7 Counter Jet Mill 2 manufactured by Hosokawa Micron Corporation
Uses 00AFG (fluid bed type, pulverized by powder-powder contact)
Then, artificial graphite powder A was supplied at a rate of 75 kg / hr and pulverized.
Was. Raman spectrum intensity ratio R value is 0.67,15
80cm^-1Of the peak near is 26.5 cm^-1so
there were. Other results are shown in Tables 2 and 3.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

[Table 5]

[0070]

As described above, the battery constituted by combining the negative electrode obtained according to the present invention, the generally used metal chalcogenide-based positive electrode for a lithium ion battery, and the organic electrolyte mainly composed of a carbonate-based solvent has a large capacity. Is large,
The irreversible capacity observed in the initial cycle is small, the storage stability and reliability of the battery when left at high temperatures are high, and the discharge characteristics at high efficiency and at low temperatures can be extremely excellent.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromi Fujii 3-1-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Prefecture Inside the Tsukuba Research Laboratory, Mitsubishi Chemical Corporation (72) Inventor Takashi Kameda 8-Chome, Ami-cho, Inashiki-gun, Ibaraki Prefecture No.3-1 Inside the Tsukuba Research Laboratory, Mitsubishi Chemical Corporation

Claims (4)

[Claims] 1. An apparent density ratio before and after treatment of 1.1 or more,
An electrode for a non-aqueous secondary battery, comprising carbonaceous or graphitic particles that have been subjected to mechanical energy treatment so that the median diameter ratio before and after treatment is 1 or less. 2. The carbon or graphite particles before treatment have an interlayer distance (d002) of 0.34 nm or less, a crystallite size (Lc) of 30 nm or more, and a true density of 2.25 g / cc or more. The electrode for a non-aqueous secondary battery according to claim 1. 3. The carbonaceous or graphitic particles after treatment have a median diameter of 5 to 50 μm, a BET specific surface area of 25 m ² / g or less, and a peak intensity of 1580 cm ⁻¹ in an argon ion laser Raman spectrum. half-value width of the R value is a ratio ° over click intensity ratio is 0.5 or less and 1580 cm ^-1 peak of 1360 cm ^-1 is 26cm ^-1 or less,
3. The electrode for a non-aqueous secondary battery according to claim 1, wherein the apparent density is 0.5 g / cc or more. 4. A non-aqueous system comprising a multi-layer carbon material obtained by mixing the carbonaceous or graphitic particles according to claim 1 with an organic compound and then carbonizing the organic compound. Electrodes for secondary batteries.