JP6561790B2 - Non-aqueous secondary battery carbon material and non-aqueous secondary battery - Google Patents

Description

  The present invention relates to a carbon material for a non-aqueous secondary battery and a non-aqueous secondary battery using the carbon material.

  In recent years, demand for high-capacity secondary batteries has increased with the downsizing of electronic devices. In particular, lithium ion secondary batteries having higher energy density and excellent large current charge / discharge characteristics have attracted attention as compared to nickel / cadmium batteries and nickel / hydrogen batteries. Although higher capacity of lithium ion secondary batteries has been widely studied, there is an increasing demand for higher performance of lithium ion secondary batteries, especially in applications such as for automobiles. It is required to achieve input / output and long life.

  As for the lithium ion secondary battery, a carbon material such as graphite is used as the negative electrode active material. Among them, graphite having a high degree of graphitization has a capacity close to 372 mAh / g, which is the theoretical capacity of graphite lithium storage. It is known that it is preferable as an active material for a negative electrode of a lithium ion secondary battery. On the other hand, when the active material layer containing these carbon materials is densified to increase the capacity, the charge / discharge irreversible capacity increases during the initial cycle in the lithium ion secondary battery due to the destruction and deformation of the material, and the input / output There were problems such as deterioration of characteristics and cycle characteristics.

  In order to solve the above problem, for example, in Patent Document 1, spheroidized natural graphite is produced by subjecting scaly natural graphite to mechanical energy treatment, and spheroidized natural graphite is used as nuclear graphite on its surface. A technique for improving fillability and high-speed charge / discharge characteristics by coating amorphous carbon is disclosed.

Patent Document 2 discloses a carbon material obtained by burning spherical natural graphite at 650 ° C. in an air atmosphere using a muffle furnace to remove fine particles on the particle surface.
Patent Document 3 discloses a carbon material in which spherical natural graphite is fed into a circulating ultrasonic homogenizer and subjected to ultrasonic irradiation to increase the amount of micropores.
Patent Document 4 discloses a carbon material having a particle number frequency of 40 to 85% with a particle size of 5 μm or less measured after applying ultrasonic irradiation for 10 minutes.

Japanese Patent No. 3534391 JP 2010-251126 A JP 2012-84520 A JP 2011-86617 A

According to the study by the present inventors, the carbon materials disclosed in Patent Documents 2 and 3 still contain fine powder in which the raw scaly graphite was destroyed during the spheronization treatment, and into the fine powder mother particles. Due to the weak binding power of these materials, there is a risk that a large amount of fine powder may be generated if a physical impact is applied when producing a negative electrode using these carbon materials. It has been found that there is a concern that input / output after the initial cycle and after the cycle cannot be sufficiently obtained.
Specifically, in the carbon material described in Patent Document 2, only the fine powder on the surface of the spheroidized natural graphite that can come into contact with the atmosphere is removed, and the fine powder generated when a physical impact is applied is difficult to remove. . The treatment applied to the carbon material described in Patent Document 3 is a treatment that can remove only fine powder that increases the amount of fine pores, and it is difficult to remove fine powder that is generated when a physical impact is applied.
The carbon material described in Patent Document 4 is generated when a physical impact is applied since the frequency of the number of particles having a particle size of 5 μm or less measured after applying ultrasonic irradiation for 10 minutes is 40 to 85%. It can be said that it is a carbon material with a large amount of fine powder.

  The present invention has been made in view of such a technical background, and an object of the present invention is to provide a carbon material for a non-aqueous secondary battery in which generation of fine powder is small due to strong particle strength even when a physical impact is applied. Therefore, it is an object of the present invention to provide a non-aqueous secondary battery, particularly a lithium ion secondary battery, which has excellent input / output characteristics and excellent cycle characteristics by using this as a negative electrode active material.

As a result of intensive studies to solve the above problems, the present inventors,
A carbon material for non-aqueous secondary batteries formed from a plurality of graphite particles capable of inserting and extracting lithium ions,
After irradiating the carbon material with 28 kHz ultrasonic waves at an output of 60 W for 5 minutes, Q _5min (%) which is the number frequency (%) of the particle diameter of 5 μm or less measured by a flow type particle image analyzer,
After irradiating a carbon material with 28 kHz ultrasonic waves at an output of 60 W for 1 minute, D50 (μm), which is a volume-based median diameter measured by a laser diffraction / scattering method,
Formula (1): Q _5min (%) / D50 (μm) ≦ 3.5
By using a carbon material characterized by satisfying the above as a negative electrode active material, it has been found that a non-aqueous secondary battery having excellent input / output characteristics and excellent cycle characteristics can be provided, and the present invention has been completed. It was.

That is, the gist of the present invention is as follows.
The present invention 1 is a carbon material for a non-aqueous secondary battery formed of a plurality of graphite particles capable of inserting and extracting lithium ions,
After irradiating the carbon material with 28 kHz ultrasonic waves at an output of 60 W for 5 minutes, Q _5min (%) which is the number frequency (%) of the particle diameter of 5 μm or less measured by a flow type particle image analyzer,
After irradiating a carbon material with 28 kHz ultrasonic waves at an output of 60 W for 1 minute, D50 (μm), which is a volume-based median diameter measured by a laser diffraction / scattering method,
Formula (1): Q _5min (%) / D50 (μm) ≦ 3.5
It is related with the carbon material characterized by satisfying.
The present invention 2 relates to a carbon material for a non-aqueous secondary battery of the present invention 1 having a Q _5min (%) of 40% or less.
In the present invention 3, the carbon material is heated from room temperature to 1000 ° C., and the total amount of desorbed CO and desorbed CO ₂ measured by a pyrolysis mass spectrometer (TPD-MS) is 125 μmol / g or less. The present invention relates to a carbon material for a non-aqueous secondary battery according to the first or second aspect.
Invention 4 is any one of Inventions 1 to 3, wherein the carbon material is heated from room temperature to 1000 ° C., and the amount of desorbed CO measured by a pyrolysis mass spectrometer (TPD-MS) is 100 μmol / g or less. The non-aqueous secondary battery carbon material.
Invention 5 is any one of Inventions 1 to 4, wherein the carbon material is heated from room temperature to 1000 ° C., and the amount of desorbed CO ₂ measured by a pyrolysis mass spectrometer (TPD-MS) is 25 μmol / g or less. The present invention relates to a carbon material for such a non-aqueous secondary battery.
This invention 6 relates to the carbon material for non-aqueous secondary batteries in any one of this invention 1-5 whose tap density is 0.7 g / cm < ³ > or more and 1.3 g / cm < ³ > or less.
This invention 7 relates to the carbon material for non-aqueous secondary batteries in any one of this invention 1-6 whose average circularity is 0.86 or more.
The present invention 8, BET specific surface area of ^2m 2 / g or more and ^{30 m} 2 / g or less, for any of the non-aqueous secondary battery carbon material of the present invention 1-7.
This invention 9 relates to the carbon material for non-aqueous secondary batteries of any one of this invention 1-8 whose volume-based median diameter (D50) is 1 micrometer or more and 50 micrometers or less.
The present invention 10 relates to the carbon material for a non-aqueous secondary battery according to any one of the present inventions 1 to 9, wherein Lc by an X-ray wide angle diffraction method is 90 nm or more and d002 is 0.337 nm or less.
This invention 11 relates to the carbon material for non-aqueous secondary batteries in any one of this invention 1-10 in which a graphite particle contains natural graphite.
The present invention 12 relates to a composite carbon material for a non-aqueous secondary battery, wherein the carbon material according to any one of the present inventions 1 to 11 is combined with a carbonaceous material.
This invention 13 is a lithium ion secondary battery provided with the positive electrode and negative electrode which can occlude / release lithium ion, and an electrolyte, Comprising: A negative electrode is charcoal for nonaqueous secondary batteries in any one of this invention 1-11. The present invention relates to a nonaqueous secondary battery comprising the material or the composite carbon material for a nonaqueous secondary battery of the twelfth aspect of the present invention.

The reason why the carbon material of the present invention can be used as a negative electrode active material to provide a non-aqueous secondary battery, particularly a lithium ion secondary battery, which has excellent input / output characteristics and excellent cycle characteristics, is as follows. Conceivable.
When forming an electrode plate using a carbon material as a negative electrode active material, usually (A) a step of preparing a slurry by kneading a carbon material and a binder, (B) applying and drying the obtained slurry to a current collector In addition, a step of increasing the density by applying pressure with a roll press or the like is employed. In the step of preparing the slurry (A), it is necessary to sufficiently knead the carbon material and the binder in order to adhere the binder to the particle surface of the carbon material. During kneading, a mechanical load is applied to the carbon material. Even in the step (B) of increasing the density, a mechanical load is applied to the carbon material. When fine powder is generated due to destruction of the carbon material due to these loads, even if the fine powder is apparently in contact with the base material of the carbon material after the electrode plate is formed, initial conditioning is required when used as a negative electrode for a non-aqueous secondary battery. By being easily separated from the carbon material base particles during charging / discharging, (b) increase in resistance between particles due to disconnection of the conductive path (reduction of electrical conductivity) and (b) increase in contact area with the electrolyte It is estimated that this leads to an increase in resistance due to an increase in side reaction (film formation) and a decrease in input / output characteristics.
In addition, when a non-aqueous secondary battery is charged, ions such as lithium are inserted into the carbon material particles that are the negative electrode active material, and the particles expand, and conversely, when discharged, the carbon material particles shrink from the carbon material particles, and the carbon material particles contract. . The non-aqueous secondary battery is a rechargeable / dischargeable battery. However, when charging / discharging is repeated, the expansion and contraction of the carbon material particles are repeated. During the expansion and contraction of the carbon material particles, if the fine powder is separated from the carbon material particles and is isolated, it is assumed that the carbon material particles do not contribute to charge / discharge and cause a decrease in battery capacity. The fine powder that is separated and isolated tends to increase as charge and discharge are repeated, and it is estimated that the cycle characteristics are deteriorated as a result.

The carbon material for a non-aqueous secondary battery of the present invention is obtained by irradiating a carbon material with 28 kHz ultrasonic waves at an output of 60 W for 5 minutes, and then measuring the number of particles having a particle diameter of 5 μm or less (%) measured by a flow type particle image analyzer. _Q5min (%), and D50 (μm), which is a volume-based median diameter measured by a laser diffraction / scattering method after irradiating a carbon material with 28 kHz ultrasonic waves at an output of 60 W for 1 minute, (1): Q _{5 min} (%) / D50 (μm) ≦ 3.5 is satisfied, but this is because the carbon material has high particle strength and is subjected to a mechanical load such as physical impact. Shows that the generation of fine powder is small. Therefore, it can be said that there is little generation | occurrence | production of a fine powder in the process of preparing the said slurry of (A), and the process of increasing the density of (B). Therefore, by using the carbon material of the present invention as a negative electrode active material, a non-aqueous secondary battery (particularly a lithium ion secondary battery) that suppresses a decrease in electrical conductivity, suppresses an increase in side reactions, and has excellent input / output characteristics. Battery). Furthermore, since the carbon material of the present invention has a high particle strength, there are few fine powders to be separated and isolated during repeated charge and discharge, and as a result, it is difficult to cause a reduction in electrical conductivity, so that a non-aqueous secondary battery having excellent cycle characteristics ( A lithium ion secondary battery).

  The carbon material for a non-aqueous secondary battery of the present invention has high particle strength even when a physical impact is applied, so that the generation of fine powder is small, and by using this as a negative electrode active material, the input / output characteristics are excellent, and the cycle It is possible to provide a non-aqueous secondary battery excellent in characteristics, particularly a lithium secondary battery.

It is a schematic diagram of a carbon material formed from a plurality of graphite particles (corresponding to a case where it is confirmed that the carbon material is composed of graphite particles having a plurality of boundary lines in observation with a scanning electron microscope). It is a schematic diagram of a carbon material formed from a plurality of graphite particles (corresponding to the case where it is confirmed by a polarizing microscope observation that it is composed of graphite particles having a plurality of different crystal orientations).

  The contents of the present invention will be described in detail below, but the present invention is not limited to these forms unless it exceeds the gist.

The carbon material for a non-aqueous secondary battery of the present invention is a carbon material for a non-aqueous secondary battery formed of a plurality of graphite particles capable of occluding and releasing lithium ions. After being irradiated for 5 minutes at an output of 60 W, Q _{5 min} (%), which is the number frequency (%) of particles having a particle diameter of 5 μm or less as measured by a flow particle image analyzer, and an ultrasonic wave of 28 kHz on a carbon material. Is irradiated with an output of 60 W for 1 minute, and D50 (μm), which is a volume-based median diameter measured by a laser diffraction / scattering method,
Formula (1): Q _5min (%) / D50 (μm) ≦ 3.5
It is characterized by satisfying.

In the present invention, the ratio of Q _5min (%), which is the frequency of the number of particles having a particle diameter of 5 μm or less after 5 minutes of ultrasonic irradiation, to D50 (μm), which is a volume-based median diameter, is defined by Equation (1). Satisfying the range indicates that the particle strength of the carbon material is strong, and even when a physical impact is applied, the generation of fine powder is small. Therefore, when the electrode plate is formed using the carbon material of the present invention as a negative electrode active material, there is little generation of fine powder. A non-aqueous secondary battery excellent in cycle characteristics, particularly a lithium ion secondary battery can be provided.

The method for measuring the frequency (%) of the number of particles having a particle diameter of 5 μm or less and the volume-based median diameter after ultrasonic irradiation in this specification is as follows.
<Number of particles having a particle size of 5 μm or less after ultrasonic irradiation (%)>
The frequency (%) of the number of particles having a particle diameter of 5 μm or less after ultrasonic irradiation is obtained by mixing 0.2 g of a sample with 50 ml of a dispersion medium and introducing it into a flow type particle image analyzer (for example, FPIA-2000 manufactured by Sysmex Industrial) After irradiating a 28 kHz ultrasonic wave with an output of 60 W for a predetermined time, the number of particles was measured with a detection range of 0.6 to 400 μm, and the ratio of the number of particles having a particle size of 5 μm or less to the whole was obtained. . In the present specification, the particle diameter of 5μm or less of particles number frequency (%), the case where the irradiation time of ultrasonic waves 5 minutes _Q 5min (%), in the case of 1 minute _Q 1min (%), when the 10-minute _Is expressed as Q _{10 min} (%).
The dispersion medium is not particularly limited as long as it can uniformly disperse the sample in the liquid. For example, alcohols such as ethanol and butanol, and water can be used. A dispersant solution containing a dispersant can also be used, and examples thereof include a 0.2% by volume aqueous solution of polyoxyethylene sorbitan monolaurate (registered trademark Tween 20), which is a surfactant.

<Volume-based median diameter (μm)>
The volume-based median diameter (μm) is obtained by mixing 0.01 g of a sample with 10 ml of a dispersion medium and introducing the mixture into a laser diffraction / scattering type particle size distribution analyzer (for example, LA-920 manufactured by HORIBA), and outputs an ultrasonic wave of 28 kHz at 60 W. And then measured as a volume-based median diameter in the apparatus. In this specification, the volume-based median diameter in a general sense is represented as d50, and the volume-based median diameter in the context of the carbon material of the present invention is represented as D50.
The dispersion medium is not particularly limited as long as it can uniformly disperse the sample in the liquid. For example, ethanol, butanol alcohols, and water can be used. A dispersant solution containing a dispersant can also be used, and examples thereof include a 0.2% by volume aqueous solution of polyoxyethylene sorbitan monolaurate (registered trademark Tween 20), which is a surfactant.

<Ratio of the number of particles having a particle diameter of 5 μm or less (%) / volume-based median diameter D50 (μm)>
In the present invention, for the carbon material of the present invention, Q _5min (%), which is the number frequency (%) of particles having a particle diameter of 5 μm or less after being irradiated with ultrasonic waves of 28 kHz for 5 minutes at an output of 60 W, and volume-based median The ratio of the diameter D50 (μm) (Q _5min / D50) is 3.5 or less, preferably 3.0 or less, more preferably 2.5 or less. On the other hand, the lower limit is not particularly limited, but can be 0.1 or more.
If it is in the above range, the generation of fine powder during electrode plate formation can be further suppressed, resistance increase due to side reactions with conductive paths and electrolytes is unlikely to occur, and non-aqueous secondary batteries excellent in input / output characteristics, particularly A non-aqueous secondary battery that can provide a lithium-ion secondary battery and that is excellent in cycle characteristics because the conductive path is not easily cut off due to separation and isolation of fine particles even during the expansion and contraction of carbon material particles during repeated charging and discharging. In particular, a lithium ion secondary battery can be provided.

Further, the ratio (Q _1min / D50) between Q _1min (%) and D50 (μm), which is the frequency (%) of the number of particles having a particle size of 5 μm or less after irradiation with 28 kHz ultrasonic waves at 60 W for 1 minute, is particularly Although not limited, it is preferably 2.4 or less, more preferably 2.0 or less, still more preferably 1.8 or less, and particularly preferably 1.5 or less. On the other hand, the lower limit is not particularly limited, but can be 0.1 or more.
Within the above range, in non-aqueous secondary batteries using the carbon material of the present invention as a negative electrode active material, in particular, lithium ion secondary batteries, it is difficult to cause disconnection of conductive paths due to separation and separation of fine powder during charge and discharge, and excellent Cycle characteristics can be easily provided.

Further, the ratio (Q _10min / D50) between Q _10min and D50 (μm), which is the number frequency (%) of particles having a particle size of 5 μm or less after irradiation with 28 kHz ultrasonic waves at 60 W for 10 minutes, is not particularly limited. However, it is preferably 4.0 or less, more preferably 3.5 or less, still more preferably 3.3 or less, and particularly preferably 3.0 or less. On the other hand, the lower limit is not particularly limited, but can be 0.1 or more.
Within the above range, in a non-aqueous secondary battery using the carbon material of the present invention as a negative electrode active material, in particular, a lithium ion secondary battery, a conductive path due to fine powder separation and isolation such as fine powder separation and isolation during charge and discharge. Cutting is difficult to occur, and excellent cycle characteristics can be easily provided.

<Graphite particles>
The carbon material of the present invention is formed from a plurality of graphite particles. Here, the graphite particles include natural graphite particles, artificial graphite particles and the like. Natural graphite particles and artificial graphite particles are easily available commercially, theoretically have a high charge / discharge capacity of 372 mAh / g, and are higher than those using other negative electrode active materials. This is preferable because the effect of improving charge / discharge characteristics at current density is great. The graphite particles preferably have few impurities, and can be used after being subjected to various known purification treatments, if necessary. Of the above, natural graphite particles are more preferable from the viewpoint of good charge / discharge characteristics at high capacity and high current density.

In the carbon material of the present invention, being formed from a plurality of graphite particles may be a combination of the graphite particles (natural graphite particles, artificial graphite particles), or a combination of two or more of the single graphite particles. There may be. Here, in the present invention, the carbon material is “formed from a plurality of graphite particles” means that the carbon material for a non-aqueous secondary battery or the cross section of the electrode containing the carbon material is scanned with a scanning electron microscope and / or polarized light. It is defined as a case where at least one of the following is confirmed in a cross section of carbon material particles having a size of about 10 to several tens of μm when observed with a microscope.
-When it is confirmed by scanning electron microscope observation that it is composed of graphite particles having a plurality of boundary lines (Fig. 1).
-When it is confirmed in the polarizing microscope observation that it is composed of graphite particles having a plurality of different crystal orientations (FIG. 2).

  Natural graphite is classified into flake graphite (Flake Graphite), scale graphite (Crystal Line Graphite), bulk graphite (Vein Graphite), and soil graphite (Amorphous Graphite). (See Graphite section of Industrial Technology Center Co., Ltd., published in 1974, and “HANDBOOK OF CARBON, GRAPHITE, DIAMOND AND FULLERENES” (issued by Noyes Publications)). The degree of graphitization is the highest at 100% for scaly graphite and massive graphite, followed by scaly graphite at 99.9%, which is suitable in the present invention. Among them, those having few impurities are preferable, and can be used after performing various known purification treatments as necessary.

  Natural graphite is produced in Madagascar, China, Brazil, Ukraine, Canada, etc., and scaly graphite is produced mainly in Sri Lanka. The main producers of soil graphite are the Korean Peninsula, China and Mexico. Among natural graphites, for example, scaly, scaly or massive natural graphite, highly purified scaly graphite and the like can be mentioned.

As artificial graphite, for example, coal tar pitch, coal heavy oil, atmospheric residue, petroleum heavy oil, aromatic hydrocarbon, nitrogen-containing cyclic compound, sulfur-containing cyclic compound, polyphenylene, polyvinyl chloride, polyvinyl Examples thereof include those obtained by baking and graphitizing organic substances such as alcohol, polyacrylonitrile, polyvinyl butyral, natural polymer, polyphenylene sulfide, polyphenylene oxide, furfuryl alcohol resin, phenol-formaldehyde resin, and imide resin.
The firing temperature can be in the range of 2500 ° C. or more and 3200 ° C. or less, and a silicon-containing compound, a boron-containing compound, or the like can be used as a graphitization catalyst during firing.

  The carbon material of the present invention can contain amorphous carbon, other metals and oxides thereof as long as the effects of the present invention are not impaired, and the carbon material of the present invention is formed from a plurality of natural graphite and artificial graphite. May be included. Examples of other metals include metals that can be alloyed with Li, such as Sn, Si, Al, and Bi.

The amorphous carbon can be obtained by firing an organic substance at a temperature usually less than 2500 ° C. The firing temperature is preferably 600 ° C. or higher, more preferably 900 ° C. or higher, still more preferably 950 ° C. or higher, preferably 2000 ° C. or lower, more preferably 1400 ° C. or lower. Further, at the time of firing, acids such as phosphoric acid, boric acid and hydrochloric acid, alkalis such as sodium hydroxide and the like can be mixed with the organic matter.
Examples of organic substances include coal heavy oils such as coal tar pitch and dry distillation liquefied oil; straight heavy oils such as atmospheric residual oil and vacuum residual oil; ethylene tar by-produced during thermal decomposition of crude oil, naphtha, etc. Heavy oils such as cracked heavy oils; aromatic hydrocarbons such as acenaphthylene, decacyclene and anthracene; nitrogen-containing cyclic compounds such as phenazine and acridine; sulfur-containing cyclic compounds such as thiophene; and aliphatic cyclics such as adamantane Compounds: Polyphenylene such as biphenyl and terphenyl, polyvinyl esters such as polyvinyl chloride, polyvinyl acetate, and polyvinyl butyral, and thermoplastic polymers such as polyvinyl alcohol.

<Method for producing carbon material for non-aqueous secondary battery>
The carbon material for a non-aqueous secondary battery of the present invention has a volume-based Q _5min (%) which is a particle number frequency (%) of a particle size of 5 μm or less after irradiating an ultrasonic wave of 28 kHz at an output of 60 W for 5 minutes. If the ratio (Q _5min / D50) of D50 (μm), which is the median diameter, satisfies the range defined by the formula (1), the manufacturing method is not particularly limited.
For example, it can be spheroidized graphite (hereinafter referred to as spheroidized graphite) using scaly graphite as a raw material. Here, the spheronization treatment is a treatment for obtaining a carbon material by repeatedly applying a mechanical action so that fine powder generated during the treatment adheres to and / or is included in the mother particles.
Hereinafter, the description will be divided into the first to third steps. Although scaly graphite will be described as a raw material, the raw material can be appropriately changed depending on the type of graphite particles.
(1st process) The process of adjusting the particle size of the scaly graphite which is a raw material;
(Second step) A step of spheroidizing the flaky graphite obtained in the first step;
(Third step) A step of subjecting the spheroidized graphite obtained in the second step to a high-purity treatment as necessary.

(1st process) The process of adjusting the particle size of the flaky graphite which is a raw material The 1st process is a process of adjusting the particle size of the flaky graphite which is a raw material. For the adjustment of the particle size, the volume-based median diameter (d50) of the scaly graphite obtained in the first step is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and preferably 200 μm or less. It can be carried out so that the thickness is preferably 100 μm or less, more preferably 50 μm or less, very preferably 35 μm or less, particularly preferably 20 μm or less, and most preferably 10 μm or less. If the volume-based median diameter (d50) of the scaly graphite obtained in the first step is within the above range, the spheroidization treatment in the second step is easy to proceed, and the increase in irreversible capacity and cycle characteristics in the nonaqueous secondary battery. Can be prevented.

Examples of a method for adjusting the volume-based median diameter (d50) of the scaly graphite obtained in the first step to the above range include a method of pulverizing and / or classifying natural graphite.
The apparatus used for the pulverization is not particularly limited. For example, the coarse pulverizer includes a shearing mill, a jaw crusher, an impact crusher, a cone crusher, and the like, and the intermediate pulverizer includes a roll crusher, a hammer mill, and the like. Examples of the fine pulverizer include a mechanical pulverizer, an airflow pulverizer, and a swirl flow pulverizer. Specific examples include a ball mill, a vibration mill, a pin mill, a stirring mill, a jet mill, a cyclone mill, and a turbo mill.
The apparatus used for the classification process is not particularly limited. For example, in the case of dry sieving, a rotary sieve, a swaying sieve, a rotating sieve, a vibrating sieve, etc. can be used. Can use gravity classifiers, inertial force classifiers, centrifugal classifiers (classifiers, cyclones, etc.), wet sieving, mechanical wet classifiers, hydraulic classifiers, settling classifiers, A centrifugal wet classifier or the like can be used.

  The scale-like graphite obtained in the first step preferably has the following physical properties as conditions other than the above conditions. The ash content in the scaly graphite is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.1% by mass or less with respect to the total mass. Moreover, it is preferable that the minimum of ash content is 1 ppm or more.

  If it is in the said range, when it is set as a lithium secondary battery, the deterioration of the battery performance by reaction with the carbon material and electrolyte solution at the time of charging / discharging can be suppressed to such an extent that it can be disregarded. Further, since a great amount of time, energy, and equipment for preventing contamination are not required for producing the carbon material, an increase in cost can be suppressed.

  The aspect ratio of the flaky graphite is usually 3 or more, preferably 5 or more, more preferably 10 or more, still more preferably 15 or more, and usually 1000 or less, preferably 500 or less, more preferably 100 or less, still more preferably. Is 50 or less. If it exists in the said range, since the contact area is moderate when it pressurizes from one direction, a strong granulated body can be formed.

  The interplanar spacing (d002) of the 002 plane of the scaly graphite by the X-ray wide angle diffraction method is usually 0.337 nm or less, preferably 0.336 nm or less, and the crystallite size Lc is usually 90 nm or more, preferably 95 nm or more. The face spacing (d002) and the crystallite size (Lc) are values indicating the crystallinity of the negative electrode material bulk. The smaller the (002) face spacing (d002) value, the larger the crystallite size. A larger (Lc) indicates a negative electrode material with higher crystallinity, and the amount of lithium entering the graphite layer approaches the theoretical value, so the capacity increases. When the crystallinity is low, excellent battery characteristics (high capacity and low irreversible capacity) when high crystalline graphite is used for the electrode are not exhibited. It is particularly preferable that the above-mentioned ranges are combined for the interplanar spacing (d002) and the crystallite size (Lc). X-ray diffraction is measured by the method described later.

The tap density of the flaky graphite is usually 0.1 g / cm ³ or more, preferably 0.15 g / cm ³ or more, more preferably 0.2 g / cm ³ or more. The tap density is measured by the method described later.

Raman R value is the ratio of the peak intensity at around 1360 cm ^-1 to the peak intensity near 1580 cm ^-1 in the argon ion laser Raman spectrum of the flake graphite is usually 0.05 or more, and usually 0.9 or less, preferably Is 0.7 or less, more preferably 0.5 or less. The R value is measured by the method described later.

The specific surface area of the scaly graphite by the BET method is usually 0.3 m ² / g or more, preferably 0.5 m ² / g or more, more preferably 1 m ² / g or more, and usually 30 m ² / g or less. Preferably it is 20 m < ² > / g or less, More preferably, it is 15 m < ² > / g or less. The specific surface area by the BET method is measured by the method described later.

(2nd process) The process of spheroidizing a flaky graphite The 2nd process is a process of performing a spheroidizing process by giving a mechanical action to the flaky graphite obtained at the 1st process. In addition to the scaly graphite obtained in the first step, further scaly graphite, scaly graphite, and ground graphite fine powder can be used in combination.

  As an apparatus used for the spheroidization process, for example, an apparatus that repeatedly gives mechanical action such as compression, friction, shearing force, etc. including interaction of particles to be processed, mainly to impact force, to the particles can be used.

  Specifically, it has a rotor with a large number of blades installed inside the casing, and when the rotor rotates at high speed, mechanical properties such as impact compression, friction, and shear force are applied to the flake graphite introduced inside. An apparatus that provides an action and performs surface treatment is preferable. Further, an apparatus having a mechanism that repeatedly gives mechanical action by circulating particles to be treated is preferable. As a method of circulating the particles to be treated, even a method in which mechanical treatment is repeatedly performed by circulating particles to be treated by one device having a circulation mechanism, several to several tens of devices are connected in series. In addition, a method may be used in which the processing target particles are continuously processed to give repeated processing. Preferable devices that give mechanical action include, for example, a hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron, kryptron orb (manufactured by Earth Technica), CF mill (manufactured by Ube Industries), jet mill, mechanofusion. Examples thereof include a system, a faculty, an ACM pulperizer, an inomizer (manufactured by Hosokawa Micron Co.), and a theta composer (manufactured by Deoksugaku Kogyo Co., Ltd.).

When processing using the above apparatus, for example, the peripheral speed of the rotating rotor can be 30 m / second or more, preferably 50 m / second or more, more preferably 60 m / second or more, and even more preferably 70 m / second. In addition, it can be set to 100 m / second or less. If it is the said range, since it can spheroidize more efficiently and a fine powder can adhere to a mother particle and / or be included in a mother particle, it is preferable.
In addition, the treatment that gives mechanical action to the flake graphite can be performed simply by passing the flake graphite, but the treatment is performed by circulating or staying in the apparatus for 30 seconds or more after the flake graphite is introduced into the apparatus. More preferably, the treatment is performed by circulating or staying in the apparatus for 1 minute or longer, more preferably for 3 minutes or longer, particularly preferably for 5 minutes or longer.

Here, the particle strength is obtained by preparing the spheroidized graphite by spheronizing the fine powder produced by the destruction of the scaly graphite during the spheroidizing process while adhering to the mother particle and / or enclosing it in the mother particle. Even if a physical impact is applied, the amount of fine powder generated can be reduced. In order to attach the fine powder generated during the spheroidizing treatment to the mother particle and / or to enclose it in the mother particle, the binding force between the mother particle and the mother particle, between the mother particle and the fine particle, or between the mother particle and the fine particle is increased. It is preferable. For example, when spheroidizing treatment is performed by repeatedly applying mechanical actions such as compression, friction, shearing force, etc., including the interaction of particles to be processed, mainly on impact force, to flaky graphite, graphite and atmospheric oxygen Reacts to generate CO ₂ and CO. As a result of intensive studies, the present inventors have made spheroidizing treatment under conditions where the amount of generated CO ₂ and CO is in a specific range, so that the particle size is between mother particles and mother particles, between mother particles and fine particles, and between fine particles and fine particles. It has been found that the binding force can be increased, and the carbon material for non-aqueous secondary batteries of the present invention has been obtained.

Specifically, in the spheronization treatment, treatment under conditions where the amount of CO generated from 1 kg of scaly graphite is 5 mmol or less is preferable, more preferably 4 mmol or less, and even more preferably 3 mmol or less. Although a minimum is not specifically limited, For example, it can be 0.05 mmol or more. Further, the treatment under the condition that the amount of CO ₂ generated from 1 kg of scaly graphite is 9 mmol or less is preferable, more preferably 8 mmol or less, and still more preferably 7 mmol or less. Although a minimum is not specifically limited, For example, it can be set as 0.1 mmol or more. Further, the treatment under the condition that the total amount of CO and CO ₂ generated from 1 kg of scaly graphite is 14 mmol or less is preferable, more preferably 12 mmol or less, and still more preferably 10 mmol or less. Although a minimum is not specifically limited, For example, it can be set to 0.15 mmol or more. By processing within the above range, the amount of graphite functional groups such as hydroxy group (—OH), carboxyl group (—C═O (—OH)), carbonyl group (═C═O), quinone group, etc. of the scaly graphite particles Therefore, the hindering of binding between the mother particles and the mother particles, between the mother particles and the fine particles, and between the fine particles and the fine particles can be reduced, and a carbon material having a high particle strength can be obtained. As a result, it is considered that the generation of fine powder can be suppressed even when a physical impact is applied to the carbon material of the present invention.

In the above range, as a method of controlling the amount of CO ₂ and CO generated in the spheronization treatment, a method of reducing the oxygen concentration by placing the inside of the device to which mechanical action is applied in an inert gas atmosphere such as nitrogen or under reduced pressure A method of treating flaky graphite so that it does not come into direct contact with oxygen; by mixing an auxiliary agent that reacts more easily with oxygen than flaky graphite, oxygen is preferentially reacted with the auxiliary agent, and the reaction between flaky graphite and oxygen In the case where the natural graphite as a raw material has come into contact with oxygen, there is a method of performing a baking treatment in an inert atmosphere and deoxidizing it. These methods may be appropriately combined.
Among these, it is not necessary to use a method of treating scaly graphite so that it does not come into direct contact with oxygen, there is no concern about suffocation due to nitrogen, and there is no need to make the device an expensive closed structure that can withstand decompression It is preferable because a step of removing the auxiliary agent to be used is unnecessary and it is not necessary to provide ancillary facilities such as a firing facility for performing deoxygenation.

Examples of the method for treating the flaky graphite so as not to directly contact oxygen include a method for spheroidizing the flaky graphite in the presence of a granulating agent that satisfies the following conditions 1) and 2).
1) It is a liquid during the step of spheroidizing the flaky graphite;
2) When the granulating agent does not contain an organic solvent or contains an organic solvent, at least one of the organic solvents does not have a flash point or has a flash point of 5 ° C. or higher. .

By having a granulating agent that satisfies the above requirements, a film of liquid can be formed on the surface of the flaky graphite, and contact between the flaky graphite and oxygen can be suppressed.
The granulating agent used in the embodiment of the present invention does not contain an organic solvent, or when it contains an organic solvent, at least one of the organic solvents does not have a flash point or has a flash point. Is 5 ° C. or higher. As a result, when flaky graphite is spheroidized, it is possible to prevent the danger of ignition, fire, and explosion of organic compounds induced by impact or heat generation, so that stable and efficient production can be carried out. I can do it.

Examples of granulating agents include, for example, coal tar, petroleum heavy oil, paraffinic oil such as liquid paraffin, synthetic oil such as olefinic oil, naphthenic oil and aromatic oil, vegetable oil and animal fat, and the like. An organic compound such as a resin binder solution in which a resin binder is dissolved in an organic solvent having a flash point of 5 ° C or higher, preferably 21 ° C or higher, an aqueous solvent such as water, And mixtures thereof.
Organic solvents with a flash point of 5 ° C or higher include alkylbenzenes such as xylene, isopropylbenzene, ethylbenzene, and propylbenzene; Hydrogens, aliphatic hydrocarbons such as octane, nonane, decane, ketones such as methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, esters such as propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, methanol, ethanol, Propanol, butanol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene Recall, alcohols such as glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, methoxypropanol, methoxypropyl-2-acetate, Methoxymethylbutanol, methoxybutyl acetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, triethylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol monophenyl ether Glycol derivatives such as ter, ethers such as 1,4-dioxane, nitrogen-containing compounds such as dimethylformamide, pyridine, 2-pyrrolidone and N-methyl-2-pyrrolidone, sulfur-containing compounds such as dimethyl sulfoxide, dichloromethane, Examples include halogen-containing compounds such as chloroform, carbon tetrachloride, dichloroethane, trichloroethane, and chlorobenzene, and mixtures thereof. For example, those having a low flash point such as toluene are not included. These organic solvents can be used alone as a granulating agent. In the present specification, the flash point can be measured by a known method.

  A well-known thing can be used as a resin binder. For example, cellulose-based resin binders such as ethyl cellulose, methyl cellulose, and salts thereof, acrylic resin binders such as polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, polyacrylic acid, and salts thereof, polymethyl methacrylate, Methacrylic resin binders such as polyethyl methacrylate and polybutyl methacrylate, and phenol resin binders can be used. Among these, coal tar, petroleum heavy oil, paraffinic oil such as liquid paraffin, and aromatic oil are preferable because they can produce a carbon material having a high degree of sphericity (roundness) and a small amount of fine powder.

  The granulating agent is preferably a granulating agent that can be efficiently removed by heat treatment and does not adversely affect battery characteristics such as capacity, output characteristics, storage / cycle characteristics, and the like. Specifically, when heated to 700 ° C. in an inert atmosphere, the weight loss is usually 50% or more, preferably 80% or more, more preferably 95% or more, still more preferably 99% or more, and particularly preferably 99.9% or more. Can be selected as appropriate.

  As a method of mixing the flaky graphite and the granulating agent, for example, a method of mixing the flaky graphite and the granulating agent using a mixer or a kneader, or an organic compound dissolved in a low viscosity diluent solvent (organic solvent). Examples thereof include a method of removing the dilution solvent (organic solvent) after mixing the granulating agent and the flaky graphite. Further, when spheroidizing graphite, the step of mixing the flaky graphite and the granulating agent and the step of spheroidizing are performed simultaneously by introducing the granulating agent and the flaky graphite into the spheronizing device. A method is also mentioned.

  The amount of the granulating agent added is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, still more preferably 3 parts by mass or more, and still more preferably 6 parts by mass or more with respect to 100 parts by mass of the flake graphite. More preferably, it is 10 parts by mass or more, particularly preferably 12 parts by mass or more, most preferably 15 parts by mass or more, preferably 1000 parts by mass or less, more preferably 100 parts by mass or less, still more preferably 80 parts by mass or less. Particularly preferably, it is 50 parts by mass or less, and most preferably 20 parts by mass or less. Within the above range, problems such as a decrease in spheroidization due to a decrease in adhesion between particles and a decrease in productivity due to adhesion of flake graphite to the apparatus are less likely to occur.

(3rd process) The process of highly purifying the obtained spheroidized graphite as needed The 3rd process is a process of highly purifying the obtained spheroidized graphite as needed. Examples of the purification treatment include acid treatment containing any one of hydrofluoric acid, nitric acid, and hydrochloric acid. Such an acid treatment is preferable because impurities such as metals, metal compounds, and inorganic compounds in the carbon material can be removed without introducing a sulfate that can be a highly active sulfur source into the system.

  For the acid treatment, an acid containing any one of hydrofluoric acid, nitric acid and hydrochloric acid may be used. Other acids such as inorganic acids such as bromic acid, boric acid or iodic acid, or citric acid, formic acid, acetic acid, An acid in which an organic acid such as acid, trichloroacetic acid or trifluoroacetic acid is appropriately mixed can also be used. Concentrated hydrofluoric acid, concentrated nitric acid and concentrated hydrochloric acid are preferable, and concentrated nitric acid and concentrated hydrochloric acid are more preferable. In addition, although you may use a sulfuric acid in an acid treatment, when using, it shall use by the quantity and density | concentration of the grade which does not impair the effect and physical property of this invention. When a plurality of acids are used, for example, a combination of hydrofluoric acid, nitric acid, and hydrochloric acid is preferable because the impurities can be efficiently removed.

<Carbonaceous composite carbon material>
Furthermore, the carbon material of the present invention can be combined with a carbonaceous material to obtain a composite carbon material for the purpose of suppressing side reactions with the electrolyte and further improving rapid charge / discharge characteristics, if necessary. Hereinafter, a composite carbon material obtained by combining a carbonaceous material with the carbon material of the present invention is also referred to as a “carbonaceous material composite carbon material”.

  An example of the treatment for compounding the carbonaceous material is a treatment for uniformly covering the carbon material of the present invention with an organic compound. Specifically, the carbon material of the present invention and an organic compound are mixed and heated in a non-oxidizing atmosphere, preferably under a flow of nitrogen, argon, carbon dioxide, etc., to carbonize or graphitize the organic compound. Is mentioned.

Organic compounds include various soft or hard coal tar pitches, heavy carbon oils such as coal liquefied oil, heavy petroleum oils such as crude oil at normal pressure or reduced pressure distillation residue, and a secondary product of ethylene production by naphtha cracking. Degradable heavy oil that is a living organism can be used.
Furthermore, heat treatment pitches such as ethylene tar pitch, FCC decant oil, and Ashland pitch obtained by heat-treating cracked heavy oil can be mentioned. Vinyl polymers such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, and polyvinyl alcohol, substituted phenol resins such as 3-methylphenol formaldehyde resin and 3,5-dimethylphenol formaldehyde resin, and aromatic carbonization such as acenaphthylene, decacyclene, and anthracene Examples thereof include nitrogen ring compounds such as hydrogen, phenazine and acridine, and sulfur ring compounds such as thiophene.

  Organic compounds that promote 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 resins, and phenol-formaldehyde resins. And thermosetting resin raw materials such as thermosetting resins such as imide resins and furfuryl alcohol. Of these, petroleum heavy oil is preferred.

  The heating temperature (firing temperature) can be appropriately selected depending on the organic compound used for the preparation of the mixture, but is normally 800 ° C or higher, preferably 900 ° C or higher, more preferably 950 ° C or higher and fully carbonized. Or graphitize. The upper limit of the heating temperature is a temperature at which the carbide of the organic compound does not reach a crystal structure equivalent to that of the scaly graphite in the mixture, and is usually 3500 ° C. at the highest. The upper limit of the heating temperature is preferably stopped at 3000 ° C, more preferably 2000 ° C, still more preferably 1500 ° C.

  After performing the above-mentioned treatment, a carbonaceous material composite carbon material can be obtained by performing crushing and / or grinding treatment. Although the shape of the carbonaceous material composite carbon material is arbitrary, the average particle size can be 2 to 50 μm, preferably 5 to 35 μm, and more preferably 8 to 30 μm. Crushing and / or pulverization and / or classification is performed as necessary so that the average particle diameter is in the above range.

  As long as the effects of the present invention are not impaired, addition of other steps and / or control conditions not described may be added.

  The content of the carbonaceous material in the carbonaceous material composite carbon material can be 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass with respect to the carbon material of the present invention. More preferably, it is 1.5% by mass or more, and can be 20% by mass or less, preferably 15% by mass or less, more preferably 10% by mass or less.

  The content of the carbonaceous material in the carbonaceous material composite carbon material can be calculated from the sample mass before and after firing the carbonaceous material composite carbon material as shown in the following formula. In the calculation, it is assumed that there is no mass change before and after firing the carbon material.

Content of carbonaceous material (mass%) = [(w2-w1) / w1] × 100
(W1 is the mass (kg) of the carbon material, and w2 is the mass (kg) of the carbonaceous composite carbon material)

<Mixed carbon material>
The carbon material of the present invention is a carbon material different from the carbon material of the present invention for the purpose of improving the orientation of the electrode plate, the permeability of the electrolytic solution, the conductive path, etc., and improving the cycle characteristics, plate swelling, etc. Can be mixed. Hereinafter, the carbon material obtained by mixing the carbon material of the present invention with a carbon material different from the carbon material of the present invention is also referred to as “mixed carbon material”.

  Examples of the carbon material different from the carbon material of the present invention include natural graphite, artificial graphite, coated graphite obtained by coating a carbon material with a carbonaceous material, amorphous carbon, and a carbon material containing metal particles or a metal compound. . These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and compositions.

As natural graphite, what has the following characteristics can be used, for example.
The volume-based median diameter of natural graphite is usually 5 μm or more, preferably 8 μm or more, more preferably 10 μm or more, further preferably 12 μm or more, and usually 60 μm or less, preferably 40 μm or less, more preferably 30 μm or less. is there. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.
The BET specific surface area of natural graphite is usually 1 m ² / g or more, preferably 2 m ² / g or more, and usually 30 m ² / g or less, preferably 15 m ² / g or less. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.
The tap density of natural graphite is usually 0.6 g / cm ³ or more, preferably 0.7 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, still more preferably 0.85 g / cm ³ or more, Moreover, it is 1.3 g / cm < ³ > or less normally, Preferably it is 1.2 g / cm < ³ > or less, More preferably, it is 1.1 g / cm < ³ > or less. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.

Examples of the artificial graphite include particles obtained by graphitizing a carbon material. For example, a single graphite precursor particle is baked while powdered, graphitized particles, and a plurality of graphite precursor particles are formed, Granulated particles that have been calcined, graphitized, and crushed can be used.
The volume-based median diameter of artificial graphite is usually 5 μm or more, preferably 10 μm or more, and is usually 60 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If it is the said range, since suppression of an electrode plate swelling and process property become favorable, it is preferable.
The artificial graphite has a BET specific surface area of usually 0.5 m ² / g or more, preferably 1.0 m ² / g or more, and usually 8 m ² / g or less, preferably 6 m ² / g or less, more preferably 4 m. ² / g or less. If it is the said range, since suppression of an electrode plate swelling and process property become favorable, it is preferable.
The tap density of the artificial graphite is usually 0.6 g / cm ³ or more, preferably 0.7 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, still more preferably 0.85 g / cm ³ or more, Usually, it is 1.5 g / cm ³ or less, preferably 1.4 g / cm ³ or less, more preferably 1.3 g / cm ³ or less. If it is the said range, since suppression of an electrode plate swelling and process property become favorable, it is preferable.

  Examples of coated graphite obtained by coating a carbon material with a carbonaceous material include, for example, particles obtained by coating, firing and / or graphitizing natural graphite or artificial graphite with the organic compound that is the precursor of the above-described carbonaceous material, natural graphite and / or artificial graphite. Examples include particles obtained by coating graphite with a carbonaceous material by chemical vapor deposition (CVD).

The volume-based median diameter of the coated graphite is usually 5 μm or more, preferably 8 μm or more, more preferably 10 μm or more, further preferably 12 μm or more, and usually 60 μm or less, preferably 40 μm or less, more preferably 30 μm or less. is there. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.
BET specific surface area of the coated graphite is usually ^{1 m} 2 / g or more, preferably ^2m 2 / g or more, more preferably 2.5 m ² / g or more and usually ^{20 m} 2 / g or less, preferably ^{10 m} 2 / g or less, more preferably 8 m ² / g or less, still more preferably 5 m ² / g or less. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.
The tap density of the coated graphite is usually 0.6 g / cm ³ or more, preferably 0.7 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, still more preferably 0.85 g / cm ³ or more, Moreover, it is 1.3 g / cm < ³ > or less normally, Preferably it is 1.2 g / cm < ³ > or less, More preferably, it is 1.1 g / cm < ³ > or less. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.

Examples of the amorphous carbon include particles obtained by firing a bulk mesophase, and particles obtained by infusibilizing an easily graphitizable organic compound and firing.
The volume-based median diameter of amorphous carbon is usually 5 μm or more, preferably 12 μm or more, and is usually 60 μm or less, preferably 40 μm or less. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.
The BET specific surface area of the amorphous carbon is usually 1 m ² / g or more, preferably 2 m ² / g or more, more preferably 2.5 m ² / g or more, and usually 8 m ² / g or less, preferably 6 m. ² / g or less, and more preferably not more than ^4m 2 / g. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.
The tap density of the amorphous carbon is usually 0.6 g / cm ³ or more, preferably 0.7 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, and further preferably 0.85 g / cm ³ or more. In addition, it is usually 1.3 g / cm ³ or less, preferably 1.2 g / cm ³ or less, more preferably 1.1 g / cm ³ or less. If it is the said range, since a high-speed charge / discharge characteristic and process property become favorable, it is preferable.

  Examples of carbon materials containing metal particles and / or metal compounds include Fe, Co, W, As, Sb, Bi, Pb, Ni, Ag, Si, Sn, Al, Zr, Cr, P, S, V. , Mn, Nb, Mo, Cu, Zn, Ge, In, Ti, etc., and / or a material obtained by combining a compound thereof and / or a compound thereof with graphite. Two or more metals may be used, and an alloy composed of two or more metals may be used. The metal particles may be alloy particles formed of two or more metal elements.

Among them, a metal selected from the group consisting of Si, Sn, As, Sb, Al, Zn, and W and / or a compound thereof is preferable, and Si and SiOx are more preferable. The general formula SiOx is obtained using silicon dioxide (SiO ₂ ) and metal silicon (Si) as raw materials, and the value of x is usually 0 <x <2, preferably 0.2 or more, more preferably 0.8. It is 4 or more, more preferably 0.6 or more, preferably 1.8 or less, more preferably 1.6 or less, and still more preferably 1.4 or less. If it is the said range, it will become high capacity | capacitance and it will become possible to reduce the irreversible capacity | capacitance by the coupling | bonding of Li and oxygen.

The volume-based median diameter of the metal particles is usually 0.005 μm or more, preferably 0.01 μm or more, more preferably 0.02 μm or more, still more preferably 0.03 μm or more, from the viewpoint of cycle life. It is 10 μm or less, preferably 9 μm or less, more preferably 8 μm or less. Within the above range, volume expansion associated with charge / discharge is reduced, and good cycle characteristics can be obtained while maintaining charge / discharge capacity.
BET specific surface area of the metal particles is usually 0.5 m ² / g or more, preferably ^{1 m} 2 / g or more and usually 120 m ² / g or less, preferably 100 m ² / g or less. If it is the said range, since the charging / discharging efficiency and discharge capacity of a battery are high, in and out of lithium in high speed charging / discharging is quick, it is preferable since it is excellent in a rate characteristic.

  The apparatus used for preparing the mixed carbon material is not particularly limited. For example, in the case of a rotary mixer, a cylindrical mixer, a twin cylindrical mixer, a double cone mixer, a regular cubic mixer, In the case of a stationary mixer, a spiral mixer, a ribbon mixer, a Muller mixer, a Helical Flyt mixer, a Pugmill mixer, a fluidized mixer, etc. .

<Physical properties of carbon materials for non-aqueous secondary batteries>
-Number of particles with a particle size of 5 μm or less (%)
With respect to the carbon material of the present invention, Q _5min (%), which is the frequency of the number of particles having a particle diameter of 5 μm or less when irradiated with ultrasonic waves of 28 kHz for 5 minutes at an output of 60 W, is preferably 40% or less, more preferably 35% or less. More preferably, it is 30% or less.
In the carbon material of the present invention, Q _1min (%), which is the frequency of the number of particles having a particle diameter of 5 μm or less when irradiated with an ultrasonic wave of 28 kHz for 1 minute at an output of 60 W, is preferably 30% or less, more preferably 27 % Or less, more preferably 23% or less.
Further, with respect to the carbon material of the present invention, the Q _10min (%), which is the frequency of the number of particles having a particle diameter of 5 μm or less when irradiated with 28 kHz ultrasonic waves at 60 W for 10 minutes, is preferably 60% or less, more preferably It is 50% or less, more preferably 45% or less, and most preferably 40% or less.
If it is the said range, at the time of slurry kneading | mixing, electrode rolling, charging / discharging, etc., it will become difficult to produce collapse of carbon material and fine powder peeling, and there exists a tendency for low-temperature input / output characteristics and cycling characteristics to become favorable.

-Volume-based median diameter (μm)
With respect to the carbon material of the present invention, the volume-based median diameter D50 (μm) is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 8 μm or more, and preferably 50 μm or less, more preferably 30 μm. Hereinafter, it is more preferably 25 μm or less.
If it is the said range, the irreversible capacity | capacitance of the nonaqueous secondary battery obtained using the carbon material of this invention will not increase easily, and it will become easy to avoid the loss of an initial stage battery capacity. In addition, it is possible to avoid the occurrence of process inconveniences such as streaking in slurry application, deterioration of high current density charge / discharge characteristics, and deterioration of low temperature input / output characteristics.

-Total amount of desorbed CO and desorbed CO ₂ from room temperature to 1000 ° C by pyrolysis mass spectrometer (TPD-MS) For the carbon material of the present invention, the temperature was raised from room temperature to 1000 ° C, and the pyrolysis mass The total of the amount of desorbed CO and the amount of desorbed CO ₂ measured by an analyzer (TPD-MS) is preferably 125 μmol / g or less, more preferably 100 μmol / g or less, and even more preferably 75 μmol / g or less. On the other hand, the lower limit is not particularly limited, but can be 1 μmol / g or more. In this specification, room temperature means 20-25 degreeC.

-Desorption CO amount from room temperature to 1000 ° C by pyrolysis mass spectrometer (TPD-MS) About the carbon material of the present invention, the temperature was raised from room temperature to 1000 ° C and measured by pyrolysis mass spectrometer (TPD-MS) The amount of desorbed CO is preferably 100 μmol / g or less, more preferably 80 μmol / g or less, and still more preferably 60 μmol / g or less. On the other hand, the lower limit is not particularly limited, but can be 1 μmol / g or more.

-Desorption CO ₂ amount from room temperature to 1000 ° C by pyrolysis mass spectrometer (TPD-MS) About the carbon material of the present invention, the temperature was raised from room temperature to 1000 ° C, and by pyrolysis mass spectrometer (TPD-MS) The measured amount of desorbed CO ₂ is preferably 25 μmol / g or less, more preferably 20 μmol / g or less, and still more preferably 15 μmol / g or less. On the other hand, the lower limit is not particularly limited, but can be 1 μmol / g or more.

  If it is the said range, graphite functional group amounts, such as a hydroxyl group (-OH), a carboxyl group (-C = O (-OH)), a carbonyl group (= C = O), a quinone group, of the graphite particle | grains of carbon material will be sufficient. A carbon material having a high particle strength can be obtained with a small amount of hindering of binding between the mother particles and the mother particles, between the mother particles and the fine particles, and between the fine particles and the fine particles due to these functional groups. As a result, it is considered that the generation of fine powder can be suppressed even when a physical impact is applied to the carbon material of the present invention. Moreover, since there are few functional groups, when using as a negative electrode of a battery, the side reaction with an electrolyte solution is hard to occur, and the effect of reducing the amount of gas generated in the battery can be expected.

-Tap density The tap density of the carbon material of the present invention is preferably 0.7 g / cm ³ or more, more preferably 0.85 g / cm ³ or more, still more preferably 0.90 g / cm ³ or more, and particularly preferably 0.8. It is 95 g / cm ³ or more, preferably 1.3 g / cm ³ or less, more preferably 1.2 g / cm ³ or less. If it is the said range, process characteristics, such as a stripe drawing at the time of electrode plate preparation, will become favorable and it will be excellent in a high-speed charge / discharge characteristic. In addition, since the carbon density in the particles is difficult to increase, the rolling property is good, and a high-density negative electrode sheet tends to be easily formed.

The tap density is measured by using a powder density measuring device to drop the sample through a sieve having an opening of 300 μm onto a cylindrical tap cell having a diameter of 1.6 cm and a volume capacity of 20 cm ^3. The volume when a tap with a length of 10 mm is performed 1000 times is measured, and the density is determined from this volume and the mass of the sample.

-Average circularity The average circularity of the carbon material of the present invention is preferably 0.86 or more, more preferably 0.88 or more, still more preferably 0.90 or more, and can be 1 or less, Preferably it is 0.99 or less, More preferably, it is 0.98 or less. The circularity is defined by the following formula, and when the circularity is 1, a theoretical sphere is obtained.

Circularity = (perimeter of equivalent circle having the same area as the particle projection shape) / (actual circumference of particle projection shape)

  If it is the said range, it exists in the tendency which can suppress the fall of the high current density charge / discharge characteristic of a non-aqueous secondary battery. Within the above range, when used in a lithium ion secondary battery, the degree of flexion of lithium ion diffusion decreases, the electrolyte solution in the interparticle voids moves smoothly, and the carbon materials can be in proper contact with each other. Therefore, there is a tendency to exhibit good rapid charge / discharge characteristics and cycle characteristics.

  The average circularity is determined by suspending 0.2 g of a sample in 50 ml of a 0.2% by mass aqueous solution of polyoxyethylene sorbitan monolaurate (registered trademark Tween 20), for example, a flow particle image analyzer (for example, Sysmex Industrial). FPIA), 28 kHz ultrasonic wave was irradiated for 1 minute at an output of 60 W, the detection range was specified as 0.6 to 400 μm, and the values measured for particles with a particle size in the range of 1.5 to 40 μm Is used. The ratio of the circumference of a circle (equivalent circle) having the same area as the measured particle projection shape as the numerator and the circumference of the measured particle projection shape as the denominator is obtained, and the average is calculated to obtain the average circularity.

・ BET specific surface area (SA)
The BET specific surface area (SA) measured by the BET method of the carbon material of the present invention is preferably 2 m ² / g or more, more preferably 3 m ² / g or more, still more preferably 4 m ² / g or more, and particularly preferably 5 m ^2. / M or more, preferably 30 m ² / g or less, more preferably 25 m ² / g or less, still more preferably 20 m ² / g or less, and particularly preferably 18 m ² / g or less.

  If it is in the above range, when used in a lithium ion secondary battery, it is possible to secure a sufficient area for lithium to enter and exit, so it has excellent high-speed charge / discharge characteristics and output characteristics, and moderately suppresses the activity of the active material against the electrolyte. Therefore, the initial irreversible capacity does not increase, and a high capacity battery tends to be manufactured. In addition, when a negative electrode is formed using the carbon material of the present invention, an increase in reactivity with the electrolyte can be suppressed, and gas generation can be suppressed, so that a preferable non-aqueous secondary battery is provided. Can do.

  The BET specific surface area is measured using a surface area meter (for example, a specific surface area measuring device “Gemini 2360” manufactured by Shimadzu Corporation), and after preliminary preliminary drying at 100 ° C. for 3 hours in a nitrogen stream on the sample, up to the liquid nitrogen temperature. Cooling and using a nitrogen helium mixed gas that is accurately adjusted so that the relative pressure value of nitrogen with respect to atmospheric pressure is 0.3, a value measured by a nitrogen adsorption BET 6-point method using a gas flow method is used.

-X-ray parameter About the carbon material of this invention, d value (interlayer distance) of the lattice plane (002 plane) calculated | required by the X-ray diffraction by the Gakushin method is preferably 0.337 nm or less, More preferably, it is 0.8. 336 nm or less, usually 0.335 nm or more. If it is the said range, since the crystallinity of graphite is high, it exists in the tendency for the increase in an initial irreversible capacity | capacitance to be suppressed. Note that 0.335 nm is a theoretical value of graphite.

  About the carbon material of this invention, the crystallite size (Lc) calculated | required by the X-ray diffraction by the Gakushin method becomes like this. Preferably it is 90 nm or more, More preferably, it is 100 nm or more. If it is the said range, it will become the particle | grains whose crystallinity is not too low, and when it is set as a non-aqueous secondary battery, a reversible capacity | capacitance becomes difficult to reduce. Note that Lc of 100 nm or more means an upper limit measurement value of graphite in the Gakushin method.

  X-ray diffraction is measured by the following method. X-ray standard high-purity silicon powder of about 15% by mass of the total amount is added to the sample to make a mixture, and CuKα ray monochromatized with a graphite monochromator is used as a radiation source, and wide-angle X-ray diffraction is performed by a reflective diffractometer method. Measure the curve. Thereafter, the interplanar spacing (d002) and the crystallite size (Lc) are obtained using the Gakushin method.

-Raman R value The Raman R value of the carbon material of the present invention is not particularly limited, but is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.15 or more, and particularly preferably 0.2 or more. Moreover, it is preferably 0.8 or less, more preferably 0.6 or less, and still more preferably 0.4 or less. In this specification, the Raman R value is measured and the intensity _{I A} of the peak _{P A} in the vicinity of 1580 cm ^-1 in the Raman spectrum obtained by Raman spectroscopy, the intensity _{I B} of a peak _{P B} in the vicinity of 1360 cm ^-1, It is defined as that calculated as the intensity ratio (I _B / I _A ). Here, the range of 1580～1620Cm ^-1 A "1580cm around ^-1", the "1360cm around ^-1" refers to the range of 1350 ^-1.

  Within the above range, the crystallinity of the carbon material particle surface is unlikely to be high, and when the density is increased, it becomes difficult for crystals to be oriented in a direction parallel to the negative electrode plate, thereby tending to avoid deterioration of load characteristics. Further, the crystal on the particle surface is not easily disturbed, and the increase in reactivity with the electrolyte of the negative electrode is suppressed, and the decrease in charge / discharge efficiency and increase in gas generation of the nonaqueous secondary battery tend to be avoided.

  The Raman spectrum can be measured with a Raman spectrometer. Specifically, the sample particles are naturally dropped into the measurement cell to fill the sample, and the measurement cell is rotated in a plane perpendicular to the laser beam while irradiating the measurement cell with an argon ion laser beam. Measure. The measurement conditions are as follows.

Argon ion laser light wavelength: 514.5 nm
Laser power on sample: 25 mW
Resolution: 4cm ^-1
Measurement range: 1100 cm ^{−1 to} 1730 cm ⁻¹
Peak intensity measurement, peak half-width measurement: background processing, smoothing processing (convolution 5 points by simple averaging)

-True density Although the true density of the carbon material of this invention is not specifically limited, Preferably it is 2.24 g / cm < ³ > or more, More preferably, it is 2.25 g / cm < ³ > or more, and an upper limit is 2.26 g / cm < ³ >. is there. The upper limit of 2.26 g / cm ³ is the theoretical value of graphite. If it is in the said range, the crystallinity of carbon is not too low, and when it is set as a non-aqueous secondary battery, it exists in the tendency which can suppress the increase in the initial irreversible capacity | capacitance.

-Surface functional group amount O / C value (%)
With respect to the carbon material of the present invention, the O / C value obtained by X-ray photoelectron spectroscopy measurement (XPS) is not particularly limited, but is preferably 0 or more, more preferably 0.1 or more, still more preferably 0.2 or more. Also, it is preferably 4 or less, more preferably 3 or less, and still more preferably 2.5 or less. If it is the said range, the desolvation reactivity of Li ion and electrolyte solution solvent in a negative electrode active material surface will be accelerated | stimulated, rapid charge / discharge characteristics will become favorable, the reactivity with electrolyte solution will be suppressed, and charge / discharge efficiency will become favorable. Tend.

  The O / C value obtained by X-ray photoelectron spectroscopy measurement (XPS) is measured using an X-ray photoelectron spectrometer (for example, ESCA manufactured by ULVAC-PHI), and the sample is placed on a sample stage so that the surface becomes flat. The spectrum of C1s (280-300 eV) and O1s (525-545 eV) is measured by multiplex measurement using the Kα ray of aluminum as the X-ray source, and the obtained C1s peak top is 284.3 eV, and the charge is corrected. The peak areas of the C1s and O1s spectra are obtained and further multiplied by the device sensitivity coefficient to calculate the surface atomic concentrations of C and O, respectively. The obtained O / C atomic concentration ratio O / C (O atom concentration / C atom concentration) × 100 is defined as the surface functional group amount O / C value of the carbon material.

<Negative electrode for non-aqueous secondary battery>
The present invention also relates to a negative electrode containing the above carbon material of the present invention. Regarding the negative electrode of the present invention, the basic configuration and the production method are not particularly limited. For example, the negative electrode can include a current collector and a negative electrode active material layer formed on the current collector, and the active material layer can contain at least the carbon material of the present invention. The negative electrode further preferably contains a binder.

  Examples of the binder include those having an olefinically unsaturated bond in the molecule. Examples thereof include styrene-butadiene rubber, styrene / isoprene / styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, and ethylene / propylene / diene copolymer. By using such a binder having an olefinically unsaturated bond, the swellability of the active material layer with respect to the electrolytic solution can be reduced. Of these, styrene-butadiene rubber is preferred because of its availability.

  By using a binder having an olefinically unsaturated bond in combination with the carbon material of the present invention as an active material, the strength of the negative electrode plate can be increased. When the strength of the negative electrode is high, deterioration of the negative electrode due to charge / discharge is suppressed, and the cycle life can be extended. Further, since the negative electrode containing the carbon material of the present invention has high adhesive strength between the active material layer and the current collector, the negative electrode is wound to reduce the battery even if the binder content in the active material layer is reduced. It is presumed that the problem that the active material layer peels from the current collector does not occur during the production.

The binder having an olefinically unsaturated bond is preferably one having a large molecular weight or a large proportion of unsaturated bonds. In the case of a binder having a large molecular weight, the weight average molecular weight is preferably 10,000 or more, more preferably 50,000 or more, and preferably 1,000,000 or less, more preferably 300,000 or less. In the case of a binder having a large ratio of unsaturated bonds, the number of moles of olefinically unsaturated bonds per gram of the total binder is preferably 2.5 × 10 ⁻⁷ mol or more, more preferably 8 × 10 ⁻⁷ mol or more, Further, the range is preferably 5 × 10 ⁻⁶ mol or less, more preferably 1 × 10 ⁻⁶ mol or less. As the binder, those satisfying at least one of these regulations regarding molecular weight and regulations regarding the ratio of unsaturated bonds are preferable, and those satisfying both regulations simultaneously are more preferable. When the molecular weight of the binder having an olefinically unsaturated bond is within the above range, mechanical strength and flexibility are excellent.

  The degree of unsaturation of the binder having an olefinically unsaturated bond is preferably 15% or more, more preferably 20% or more, still more preferably 40% or more, and preferably 90% or less, more preferably 80% or less. . The degree of unsaturation represents the ratio (%) of the double bond to the repeating unit of the polymer.

  In the present invention, a binder having no olefinically unsaturated bond can also be used as long as the effects of the present invention are not impaired. The binder having no olefinically unsaturated bond can be used in combination with the binder having the olefinically unsaturated bond. The mixing ratio of the binder having no olefinically unsaturated bond to the binder having an olefinically unsaturated bond is preferably 150% by mass or less, more preferably 120% by mass or less. If it is this range, application property can be improved, suppressing that the intensity | strength of an active material layer falls by using together the binder which does not have an olefinically unsaturated bond.

  Examples of the binder having no olefinic unsaturated bond include thickening polysaccharides such as methylcellulose, carboxymethylcellulose, starch, carrageenan, pullulan, guar gum, xanthan gum (xanthan gum), polyethers such as polyethylene oxide and polypropylene oxide, Vinyl alcohols such as polyvinyl alcohol and polyvinyl butyral, polyacids such as polyacrylic acid and polymethacrylic acid, or metal salts of these polymers, fluorine-containing polymers such as polyvinylidene fluoride, alkane polymers such as polyethylene and polypropylene, and these A copolymer etc. are mentioned.

  When the carbon material of the present invention is used in combination with the above-mentioned binder having an olefinically unsaturated bond, the ratio of the binder used for the active material layer can be reduced as compared with the conventional material. Specifically, the carbon material of the present invention and a binder (in some cases, it may be a mixture of a binder having an unsaturated bond and a binder having no unsaturated bond as described above). The weight ratio of each is preferably 90/10 or more, more preferably 95/5 or more, and preferably 99.9 / 0.1 or less, more preferably 99.5 / 0 in terms of dry mass ratio. .5 or less. If it is the said range, the reduction | decrease in a capacity | capacitance and resistance increase can be suppressed, and also it is excellent also in electrode plate strength.

  The negative electrode of the present invention is formed by dispersing the carbon material of the present invention and a binder in a dispersion medium to form a slurry, which is applied to a current collector. Examples of the dispersion medium include organic solvents such as alcohol, water, and the like. If necessary, a conductive agent may be added to the slurry. Examples of the conductive agent include carbon black such as acetylene black, ketjen black, and furnace black, and fine powder made of Cu, Ni, or an alloy thereof having an average particle diameter of 1 μm or less. The addition amount of the conductive agent is preferably 10% by mass or less with respect to the carbon material of the present invention.

  A conventionally well-known thing can be used as a collector which apply | coats a slurry. Specific examples include metal thin films such as rolled copper foil, electrolytic copper foil, and stainless steel foil. The thickness of the current collector is preferably 4 μm or more, more preferably 6 μm or more, and preferably 30 μm or less, more preferably 20 μm or less.

After applying the slurry on the current collector, it is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, and preferably 200 ° C. or lower, more preferably 195 ° C. or lower, in dry air or an inert atmosphere. Dry to form an active material layer.
The thickness of the active material layer obtained by applying and drying the slurry is preferably 5 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, and preferably 200 μm or less, more preferably 100 μm or less, further Preferably it is 75 micrometers or less. When the thickness of the active material layer is within the above range, it is excellent in practicality as a negative electrode in consideration of the particle size of the active material, and a sufficient Li occlusion / release function for a high-density current value can be obtained. .

The density of the carbon material in the active material layer varies depending on the application, but in an application in which capacity is important, it is preferably 1.55 g / cm ³ or more, more preferably 1.6 g / cm ³ or more, and still more preferably 1.65 g / cm. It is cm ³ or more, particularly preferably 1.7 g / cm ³ or more, and preferably 1.9 g / cm ³ or less. If it is the said range, the capacity | capacitance of the battery per unit volume can fully be ensured, and a rate characteristic will become difficult to fall.

<Non-aqueous secondary battery>
The present invention also relates to a non-aqueous secondary battery provided with the negative electrode of the present invention. With respect to the non-aqueous secondary battery of the present invention, particularly the lithium ion secondary battery, the basic configuration and manufacturing method are not particularly limited. For example, a lithium ion secondary battery can include a positive electrode and a negative electrode capable of inserting and extracting lithium ions, and an electrolyte, and the negative electrode can be used as the negative electrode of the present invention. The positive electrode can have a positive electrode active material layer containing a positive electrode active material and a binder formed on a current collector.

Examples of the positive electrode active material include metal chalcogen compounds that can occlude and release alkali metal cations such as lithium ions during charge and discharge. Examples of metal chalcogen compounds include vanadium oxide, molybdenum oxide, manganese oxide, chromium oxide, titanium oxide, tungsten oxide and other transition metal oxides, vanadium sulfide, molybdenum sulfide. , Transition metal sulfides such as CuS, transition metal sulfides such as NiPS ₃ and FePS ₃ , selenium compounds of transition metals such as VSe ₂ and NbSe ₃ , Fe _0.25 V _0. Examples thereof include composite oxides of transition metals such as ₇₅ S ₂ and Na _0.1 CrS ₂ and composite sulfides of transition metals such as LiCoS ₂ and LiNiS ₂ .

Among them, V ₂ O ₅ , V ₅ O ₁₃ , VO ₂ , Cr ₂ O ₅ , MnO ₂ , TiO ₂ , MoV ₂ O ₈ , LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , TiS ₂ , V ₂ S ₅ , Cr _0.25 V _0.75 S ₂ , Cr _0.5 V _0.5 S _{2 and the} like are preferable, and particularly preferable are LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , some of these transition metals and other It is a lithium transition metal composite oxide substituted with a metal. These positive electrode active materials may be used alone or in combination of two or more.

  The binder for binding the positive electrode active material is not particularly limited, and any known one can be selected and used. Examples thereof include inorganic compounds such as silicate and water glass, resins having no unsaturated bond such as Teflon (registered trademark) and polyvinylidene fluoride. Among them, a resin having no unsaturated bond is preferable because it is difficult to be decomposed during the oxidation reaction. The weight average molecular weight of these resins is usually 10,000 or more, preferably 100,000 or more, and usually 3 million or less, preferably 1 million or less.

  The positive electrode active material layer may contain a conductive material in order to improve the conductivity of the electrode. The conductive material is not particularly limited as long as it is capable of imparting conductivity by mixing an appropriate amount in the active material. Usually, carbon powder such as acetylene black, carbon black and graphite, various metal fibers, powder, and foil. Etc.

  The positive electrode plate is formed by slurrying a positive electrode active material or a binder with a solvent in the same manner as in the production of the negative electrode as described above, and applying and drying on a current collector. As the positive electrode current collector, aluminum, nickel, stainless steel (SUS) or the like is used, but it is not particularly limited.

  Examples of the electrolyte include a non-aqueous electrolyte obtained by dissolving a lithium salt in a non-aqueous solvent, and a non-aqueous electrolyte obtained by forming a gel, rubber, or solid sheet with an organic polymer compound.

  The non-aqueous solvent used in the non-aqueous electrolyte is not particularly limited, and any known one can be selected and used. For example, chain carbonates such as diethyl carbonate, dimethyl carbonate and ethyl methyl carbonate; cyclic carbonates such as ethylene carbonate, propylene carbonate and butylene carbonate; chain ethers such as 1,2-dimethoxyethane; tetrahydrofuran, 2-methyl Examples include cyclic ethers such as tetrahydrofuran, sulfolane and 1,3-dioxolane; chain esters such as methyl formate, methyl acetate and methyl propionate; cyclic esters such as γ-butyrolactone and γ-valerolactone.

  These non-aqueous solvents may be used alone or in combination of two or more. In the case of a mixed solvent, a combination of a cyclic carbonate and a chain carbonate is preferable. Furthermore, when the cyclic carbonate is a combination of ethylene carbonate and propylene carbonate, it is preferable in that high ionic conductivity can be exhibited even at a low temperature, and the low-temperature unchargeable characteristics are improved. Among them, propylene carbonate is preferably in the range of 2% by mass to 80% by mass, more preferably in the range of 5% by mass to 70% by mass, and further in the range of 10% by mass to 60% by mass with respect to the entire non-aqueous solvent. preferable. When the proportion of propylene carbonate is lower than the above, the ionic conductivity at low temperature decreases, and when the proportion of propylene carbonate is higher than the above, when a graphite-based electrode is used, propylene carbonate solvated with lithium ions enters the graphite layer. The co-insertion causes a delamination degradation of the graphite-based negative electrode active material, and there is a problem that a sufficient capacity cannot be obtained.

The lithium salt used for the non-aqueous electrolyte is not particularly limited, and can be appropriately selected from lithium salts known to be usable for this application. For example, halides such as LiCl and LiBr, perhalogenates such as LiClO ₄ , LiBrO ₄ and LiClO ₄ , inorganic lithium salts such as inorganic fluoride salts such as LiPF ₆ , LiBF ₄ and LiAsF ₆ , LiCF ₃ SO ₃ , Fluorine-containing organic lithium salts such as perfluoroalkanesulfonic acid salts such as LiC ₄ F ₉ SO ₃ and perfluoroalkanesulfonic acid imide salts such as lithium trifluorosulfonimide ((CF ₃ SO ₂ ) ₂ NLi) . Of these, LiClO ₄ , LiPF ₆ , and LiBF ₄ are preferable.

A lithium salt may be used individually by 1 type, or may use 2 or more types together. The concentration of the lithium salt in the nonaqueous electrolytic solution is usually in the range of 0.5 mol / L or more and 2.0 mol / L or less.
In addition, when an organic polymer compound is included in the non-aqueous electrolyte and used in the form of a gel, rubber, or solid sheet, the organic polymer compound may be a polyether-based polymer such as polyethylene oxide or polypropylene oxide. Molecular compound; Cross-linked polymer of polyether polymer compound; Vinyl alcohol polymer compound such as polyvinyl alcohol and polyvinyl butyral; Insolubilized product of vinyl alcohol polymer compound; Polyepichlorohydrin; Polyphosphazene; Polysiloxane; , Vinyl polymer compounds such as polyvinylidene carbonate and polyacrylonitrile; poly (ω-methoxyoligooxyethylene methacrylate), poly (ω-methoxyoligooxyethylene methacrylate-co-methyl methacrylate), poly ( And polymer copolymers such as hexafluoropropylene-vinylidene fluoride).

The non-aqueous electrolyte may further contain a film forming agent. Examples of the film forming agent include carbonate compounds such as vinylene carbonate, vinyl ethyl carbonate, and methylphenyl carbonate; alken sulfides such as ethylene sulfide and propylene sulfide; sultone compounds such as 1,3-propane sultone and 1,4-butane sultone; maleic acid Acid anhydrides such as anhydride and succinic anhydride are listed. Furthermore, an overcharge inhibitor such as diphenyl ether or cyclohexylbenzene may be added.
When the additive is used, the content thereof is usually 10% by mass or less, preferably 8% by mass or less, more preferably 5% by mass or less, and further preferably 2% by mass with respect to the total mass of the non-aqueous electrolyte solution. The following ranges are preferred. If it is the said range, it can avoid affecting other battery characteristics, such as increase of initial irreversible capacity | capacitance, a low temperature characteristic, and a fall of a rate characteristic, because there is too much content of an additive.

As the electrolyte, a polymer solid electrolyte that is a conductor of an alkali metal cation such as lithium ion can also be used. Examples of the polymer solid electrolyte include those obtained by dissolving a lithium salt in the aforementioned polyether polymer compound, and polymers in which the terminal hydroxyl group of the polyether is substituted with an alkoxide.
In order to prevent a short circuit between the electrodes, a porous separator such as a porous film or a nonwoven fabric is usually interposed between the positive electrode and the negative electrode. In this case, the nonaqueous electrolytic solution is used by impregnating a porous separator. Examples of the material for the separator include polyolefins such as polyethylene and polypropylene, polyethersulfone, and the like, and polyolefin is preferable.

  The form of the non-aqueous secondary battery of the present invention is not particularly limited. For example, 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 can be given. In addition, by storing batteries of these forms in an optional outer case, the battery can be used in an arbitrary shape such as a coin shape, a cylindrical shape, or a square shape.

  The procedure for assembling the non-aqueous secondary battery of the present invention is not particularly limited, and may be assembled by an appropriate procedure according to the structure of the battery. For example, a negative electrode can be placed on an outer case, an electrolytic solution and a separator can be provided thereon, and a positive electrode can be placed so as to face the negative electrode, and can be caulked together with a gasket and a sealing plate to form a battery.

  EXAMPLES Specific examples of the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

The characteristics of the carbon materials of the examples or comparative examples were measured as follows.
<Measurement of volume-based median diameter D50>
0.01 g of sample was suspended in 10 ml of ethanol, introduced into a laser diffraction / scattering particle size distribution device (LA-920 manufactured by HORIBA), irradiated with 28 kHz ultrasonic waves at 60 W output for 1 minute, and then volume-based median The diameter D50 was measured (ultrasound intensity 4, relative refractive index 1.50). However, in Examples 3 and 4 and Comparative Examples 3 and 4, 10 ml of a 0.2 vol% aqueous solution of polyoxyethylene sorbitan monolaurate (registered trademark Tween 20) was used as a dispersion medium instead of ethanol.

<Frequency of the number of particles having a particle size of 5 μm or less>
A sample of 0.2 g was suspended in 50 ml of ethanol, introduced into a flow particle image analyzer (FPIA-2000 manufactured by Sysmex Industrial Co., Ltd.), irradiated with 28 kHz ultrasonic waves at an output of 60 W for a predetermined time, and the detection range was 0. The number of particles was measured by designating from 6 to 400 μm, and the ratio of the number of particles having a particle diameter of 5 μm or less to the whole was determined. However, in Examples 3 and 4 and Comparative Examples 3 and 4, 50 ml of a 0.2% by volume aqueous solution of polyoxyethylene sorbitan monolaurate (registered trademark Tween 20) was used as a dispersion medium instead of ethanol. When the irradiation time of ultrasonic waves is 5 minutes, the number frequency (%) of particles having a particle diameter of 5 μm or less is Q _{5 min} (%). When the number of particles is 1 minute, the frequency of particle numbers (%) having a particle diameter of 5 μm or less is Q _{1 min} (%). ) The frequency (%) of the number of particles having a particle diameter of 5 μm or less in the case of 10 minutes was expressed as Q _10min (%).

<Tap density>
The measurement was performed using a powder density measuring device (Tap Denser manufactured by Hosokawa Micron Corporation). The sample is passed through a sieve having a mesh opening of 300 μm, dropped into a cylindrical tap cell having a diameter of 1.6 cm and a volume capacity of 20 cm ³ , filled into the cell, and measuring the volume when a tap with a stroke length of 10 mm is performed 1000 times. Then, the density was obtained from the volume and the mass of the sample, and was defined as the tap density.

<Average circularity>
0.2 g of a sample was suspended in 50 ml of a 0.2 mass% aqueous solution of polyoxyethylene sorbitan monolaurate (registered trademark Tween 20) and introduced into a flow type particle image analyzer (“FPIA” manufactured by Sysmex Industrial). After irradiating a 28 kHz ultrasonic wave with an output of 60 W for 1 minute, the detection range was specified as 0.6 to 400 μm, and the values measured for particles having a particle size in the range of 1.5 to 40 μm were used. The ratio of the circumference of the circle having the same area as the measured particle projection shape (equivalent circle) as the numerator and the circumference of the measured particle projection shape as the denominator was obtained, and the average was calculated to obtain the average circularity.

<BET specific surface area>
Using a surface area meter (specific surface area measuring device “Gemini 2360” manufactured by Shimadzu Corporation), the sample was subjected to preliminary vacuum drying at 100 ° C. for 3 hours under nitrogen flow, then cooled to liquid nitrogen temperature, and nitrogen with respect to atmospheric pressure. Using a nitrogen helium mixed gas that was accurately adjusted so that the relative pressure value of the gas was 0.3, the nitrogen adsorption BET 6-point method by gas flow method was used.

<Lc and d002>
X-ray standard high-purity silicon powder is added to the sample, a 15% by mass sample is obtained, CuKα ray monochromatized with a graphite monochromator is used as a radiation source, and a wide angle X-ray diffraction curve is obtained by a reflection diffractometer method. Was measured. The interplanar spacing (d002) and crystallite size (Lc) were determined using the Gakushin method.

<Desorption CO amount and CO ₂ amount from room temperature to 1000 ° C. by pyrolysis mass spectrometer (TPD-MS)>
The sample was heat-treated at 200 ° C. for 5 hours under nitrogen flow. Thereafter, the mixture was heated from room temperature to 1000 ° C. at a heating rate of 10 ° C./min under a flow of He gas at 50 ml / min, and the amount of CO and CO ₂ generated at that time were measured using a pyrolysis mass spectrometer (TPD-MS). The amount of desorbed CO per 1 g of sample (μmol / g) and the amount of desorbed CO ₂ (μmol / g) were determined.

Production of an electrode sheet and a non-aqueous battery (laminated battery) using the carbon materials of Examples or Comparative Examples was performed as follows.
<Production of electrode sheet>
An electrode plate having an active material layer with an active material layer density of 1.60 ± 0.03 g / cm ³ was produced using the carbon material of the example or the comparative example. Specifically, 50.00 ± 0.02 g of a carbon material, 50.00 ± 0.02 g (0.500 g in terms of solid content) of a 1 mass% carboxymethylcellulose sodium salt aqueous solution, and styrene having a weight average molecular weight of 270,000 -Aqueous dispersion of butadiene rubber 1.00 ± 0.05 g (0.5 g in terms of solid content) was stirred for 5 minutes with a hybrid mixer manufactured by Keyence and defoamed for 30 seconds to obtain a slurry.

The slurry is applied to a width of 10 cm using a small die coater made by ITOCHU machining so that the carbon material adheres to 12.00 ± 0.3 mg / cm ² on a 10 μm thick copper foil as a current collector. Then, roll pressing was performed using a roller having a diameter of 20 cm to adjust the density of the active material layer to 1.60 ± 0.03 g / cm ³ to obtain an electrode sheet.

<Production method of non-aqueous secondary battery (laminated battery)>
The electrode sheet is cut into 4 cm × 3 cm to form a negative electrode, a positive electrode made of LiNi _1/3 Mn _1/3 Co _1/3 O ₂ (NMC) is cut out with the same area, and a separator (porous polyethylene) is formed between the negative electrode and the positive electrode. (Made of film) and put together. A laminate type battery was prepared by injecting 250 μl of an electrolytic solution in which LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate (volume ratio = 3: 3: 4) so as to be 1.2 mol / L. Was made.

<Preparation of non-aqueous secondary battery (2016 coin type battery)>
The electrode sheet was punched into a disk shape with a diameter of 12.5 mm, and the lithium metal foil was punched into a disk shape with a diameter of 14 mm as a counter electrode. Between the two electrodes, a separator (porous polyethylene film) impregnated with an electrolytic solution in which LiPF ₆ was dissolved at 1 mol / L in a mixed solvent of ethylene carbonate and ethyl methyl carbonate (volume ratio = 3: 7). 2016 coin type batteries were prepared.

The characteristics of the obtained laminate type battery were measured as follows.
<Initial low temperature output characteristics>
With respect to the laminate type battery, initial low-temperature output characteristics were measured by the following method.
For a laminated battery that has not undergone a charge / discharge cycle, a voltage range of 4.1 V to 3.0 V at 25 ° C., a current value of 0.2 C (the current value that discharges the rated capacity with a discharge capacity of 1 hour rate in 1 hour) 1 C. The same shall apply hereinafter. 3 cycles, voltage range 4.2 V to 3.0 V, current value 0.2 C (when charging, constant voltage charging was further performed at 4.2 V for 2.5 hours) ) Initial charge / discharge was performed for 2 cycles.
About the battery which performed this initial charging / discharging, after charging with a current value of 0.2 C to a charge rate (SOC, State Of Charge) 50%, in a low temperature environment of −30 ° C., 1/8 C, 1 / 4C, 1 / 2C, 1.5C, and 2C were discharged at a constant current for 2 seconds, and a drop in battery voltage after 2 seconds in each condition discharge was measured. Calculate the current value I that can flow for 2 seconds when the upper limit of charge voltage is 3V from the measured value, and use the formula: 3 x I (W) as the initial 2 second low temperature output characteristics of each battery. It was.
Similarly, a current value I that can flow for 10 seconds was calculated, and the calculated value was used as an initial 10-second low-temperature output characteristic.

<Low-temperature output characteristics after cycle>
About the said laminate type battery, the low-temperature output characteristic after a cycle was measured with the following method.
For a laminated battery that has not undergone a charge / discharge cycle, a voltage range of 4.1 V to 3.0 V at 25 ° C., a current value of 0.2 C for 3 cycles, a voltage range of 4.2 V to 3.0 V, a current value of 0. Charge / discharge of 300 cycles was performed at 2C (at the time of charging, constant voltage charging was further performed at 4.2 V for 2.5 hours).
The battery that was charged / discharged for 300 cycles was charged at a current value of 0.2 C up to a charge rate (SOC) of 50%, and then at 1-30 C, 1/4 C, 1 A constant current discharge was performed for 2 seconds at each current value of / 2C, 1.5C, and 2C, and a drop in battery voltage after 2 seconds in each condition discharge was measured. Calculate the current value I that can flow for 2 seconds when the upper limit of charge voltage is 3V from the measured value, and calculate the value calculated by the formula: 3 x I (W) for 2 seconds after each battery cycle. Characteristic.
Similarly, a current value I that can flow for 10 seconds was calculated, and the calculated value was defined as a low-temperature output characteristic for 10 seconds after the cycle.

<Discharge capacity>
Using the non-aqueous secondary battery (2016 coin type battery) produced by the above method, the capacity during battery charging / discharging was measured by the following measurement method.
Charge to 5 mV with respect to the lithium counter electrode at a current density of 0.05 C, and further charge to a current density of 0.005 C at a constant voltage of 5 mV. After doping lithium into the negative electrode, the current density of 0.1 C Then, the lithium counter electrode was discharged to 1.5V. Subsequently, the second charge / discharge was performed at the same current density, and the discharge capacity of the second cycle was defined as the discharge capacity of the material.

Example 1
The flaky natural graphite having a volume-based median diameter d50 of 100 μm is pulverized by a mechanical pulverizer (“Turbo Mill” manufactured by Freund Kogyo Co., Ltd.) having a pulverizing rotor and liner, and the flaky natural graphite having a volume-based median diameter d50 of 30 μm. Graphite was obtained. While using 300 g of the obtained scaly natural graphite with a hybridization system NHS-1 manufactured by Nara Machinery Co., Ltd., the fine powder produced during the spheronization treatment is attached to the base material and encapsulated in the spheroidized particles, the rotor peripheral speed is 88 m. A spheronization treatment was performed by mechanical action for 1 minute per second. Next, by adding 30 g of liquid paraffin (manufactured by Wako Pure Chemical Industries, Ltd., first grade, flash point 238 ° C.) to the spheroidized graphite, the amount of oxygen touching the graphite is reduced, and the spheronization process is further performed for 2 minutes. It was. The gas phase during the treatment was sampled and analyzed by gas chromatography. As a result, the amount of CO generated from 1 kg of scaly natural graphite was 0.3 mmol, and the amount of CO ₂ was 0.9 mmol.

The volume-based median diameter D50 (μm) of the obtained carbon material is 15.0 μm, and the number frequency (fine powder amount) Q _5min (%) of the particle diameter of 5 μm or less after 5 minutes of ultrasonic irradiation is 13. %, Q _5min (%) / D50 (μm) was 0.9.
Q _1min (%) and Q _10min (%), which are the number frequency (fine powder amount) of particles having a particle diameter of 5 μm or less after 1 minute of ultrasonic irradiation and 10 minutes after ultrasonic irradiation of the obtained carbon material, are each 5%. Q _{1 min} (%) / D50 (μm) and Q _{10 min} (%) / D50 (μm) were 0.3 and 1.8, respectively.
The obtained carbon material had an average circularity of 0.89, a tap density of 0.79 g / cm ³ , and a BET specific surface area of 12.9 m ² / g.
The obtained carbon material was embedded in a resin, a sample for cross-sectional observation was prepared, and cross-sectional observation was performed with a scanning electron microscope. As a result, the shape as shown in FIG. Was found to be formed.
The amount of desorbed CO and CO ₂ from room temperature to 1000 ° C. by pyrolysis mass spectrometry (TPD-MS) of the obtained carbon material is 9 μmol / g for desorbed CO and ₂ μmol / g for desorbed CO _2. g.
The obtained carbon material had an Lc of 100 nm or more and a d002 of 0.336 nm according to the X-ray wide angle diffraction method.
The physical properties of the obtained carbon material are shown in Tables 1-3. In addition, Table 4 shows the initial output and post-cycle output characteristics of a laminate type battery manufactured using the obtained carbon material. Furthermore, Table 4 shows the discharge capacity characteristics of the 2016 coin-type battery produced using the obtained carbon material.

(Example 2)
Scalar natural graphite and liquid paraffin are mixed before spheronization treatment so that the amount of CO generated from 1 kg of flaky natural graphite is 0.3 mmol and the amount of CO ₂ is 1.0 mmol, and the spheronization treatment is performed for 3 minutes. The same procedure as in Example 1 was performed except that the test was performed.
Q _{5 min} (%) / D50 (μm) of the obtained carbon material was 1.1.
The obtained carbon material was embedded in a resin, a sample for cross-sectional observation was prepared, and cross-sectional observation was performed with a scanning electron microscope. As a result, the shape as shown in FIG. It was found that it was formed from.
The physical properties of the obtained carbon material are shown in Tables 1-3. Table 4 shows the characteristics of the laminate type battery and the 2016 coin type battery manufactured using the obtained carbon material.

(Example 3)
Instead of liquid paraffin, ethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd., first grade, flash point 110 ° C.) so that the amount of CO generated from 1 kg of scaly natural graphite is 2.1 mmol and the amount of CO ₂ is 4.0 mmol. This was carried out in the same manner as in Example 1 except that the spheronization treatment was performed using. Furthermore, the obtained carbon material was dried at 250 ° C. under a nitrogen atmosphere.
Q _5min (%) / D50 (μm) of the obtained carbon material was 1.9.
The obtained carbon material was embedded in a resin, a sample for cross-sectional observation was prepared, and cross-sectional observation was performed with a scanning electron microscope. As a result, the shape as shown in FIG. It was found that it was formed from.
The physical properties of the obtained carbon material are shown in Tables 1-3. Table 4 shows the characteristics of the laminate type battery and the 2016 coin type battery manufactured using the obtained carbon material.

Example 4
Inside the device where the scaly graphite and ethylene glycol are mixed before spheronization treatment and mechanical action is applied so that the amount of CO generated from 1 kg of scaly natural graphite is 2.5 mmol and the amount of CO ₂ is 5.0 mmol. Was carried out in the same manner as in Example 3 except that the spheronization treatment was performed for 3 minutes.
Q _5min (%) / D50 (μm) of the obtained carbon material was 2.3.
The obtained carbon material was embedded in a resin, a sample for cross-sectional observation was prepared, and cross-sectional observation was performed with a scanning electron microscope. As a result, the shape as shown in FIG. It was found that it was formed from.
The physical properties of the obtained carbon material are shown in Tables 1-3. Table 4 shows the characteristics of the laminate type battery and the 2016 coin type battery manufactured using the obtained carbon material.

(Comparative Example 1)
The same procedure as in Example 1 was performed except that flaky natural graphite having a volume-based median diameter d50 of 30 μm used in Example 1 was spheroidized in an air atmosphere. As a result of sampling the gas phase during the treatment and analyzing by gas chromatography, the amount of CO generated from 1 kg of scaly natural graphite was 7.2 mmol, and the amount of CO ₂ was 11.2 mmol.
Resulting a volume median diameter of the carbon material D50 ([mu] m) is 14.4μm, _{Q 5min} (%) is a particle diameter of 5μm or smaller particles number frequency of ultrasound after 5 minutes (amount of fine powder) 75% , Q _5min (%) / D50 (μm) was 5.2.
The obtained carbon material was embedded in a resin, a sample for cross-sectional observation was prepared, and cross-sectional observation was performed with a scanning electron microscope. As a result, the shape as shown in FIG. It was found that it was formed from.
The physical properties of the obtained carbon material are shown in Tables 1-3. Table 4 shows the characteristics of the laminate type battery and the 2016 coin type battery manufactured using the obtained carbon material.

(Comparative Example 2)
The carbon material obtained by the spheroidizing treatment of Comparative Example 1 was dried in a nitrogen atmosphere in the same manner as in Example 3 to prepare the carbon material of Comparative Example 2.
Q _5min (%) / D50 (μm) of the obtained carbon material was 5.3.
The obtained carbon material was embedded in a resin, a sample for cross-sectional observation was prepared, and cross-sectional observation was performed with a scanning electron microscope. As a result, the shape as shown in FIG. It was found that it was formed from.
The physical properties of the obtained carbon material are shown in Tables 1-3. Table 4 shows the characteristics of the laminate type battery and the 2016 coin type battery manufactured using the obtained carbon material.

(Comparative Example 3)
For the commercially available natural graphite A subjected to spheronization treatment, D50 (μm) measured in the same manner as in Example 3 was 20.3 μm, Q _5min (%) was 76%, and Q _5min (%) / D50 (μm) was 3. .7.
Natural graphite A was embedded in a resin, a sample for cross-sectional observation was prepared, and cross-sectional observation was performed with a scanning electron microscope. As a result, a shape as shown in FIG. 1 was confirmed. It was found that it was formed.
The physical properties of natural graphite A are shown in Tables 1-3. Table 4 shows the characteristics of a laminate type battery and a 2016 coin type battery manufactured using natural graphite A.

(Comparative Example 4)
With respect to commercially available natural graphite B subjected to spheronization treatment, D50 (μm) measured in the same manner as in Comparative Example 3 was 16.0 μm, Q _5min (%) was 69%, and Q _5min (%) / D50 (μm) was 4 .3.
A natural graphite B was embedded in a resin, a sample for cross-sectional observation was prepared, and the cross-section was observed with a scanning electron microscope. As a result, the shape as shown in FIG. 1 was confirmed. It was found that it was formed.
The physical properties of natural graphite B are shown in Tables 1-3. Table 4 shows the characteristics of the laminate type battery and the 2016 coin type battery manufactured using natural graphite B.

* 11 ^* (μmol / g) is calculated by rounding off the total amount 11.3 (μmol / g) of the desorbed CO amount 9.7 (μmol / g) and the desorbed CO ₂ amount 1.6 (μmol / g). Value.

The batteries using Examples 1 to 4 which are the carbon materials of the present invention are excellent in the low temperature output characteristics at the initial stage and after the cycle. On the other hand, the carbon materials used in Comparative Examples 1 to 4 are Q _5min (%) which is the number frequency (fine powder amount) of particle diameter 5 μm or less 5 minutes after ultrasonic irradiation and D50 which is a volume-based median diameter. Since the ratio of (μm) is outside the specified range, the low-temperature input / output characteristics at the initial stage and after the cycle are low.

  By using the carbon material of the present invention as an active material for a non-aqueous secondary battery negative electrode, it is possible to provide a non-aqueous secondary battery with high capacity, excellent input / output characteristics, and cycle characteristics.

Claims (13)

A carbon material for non-aqueous secondary batteries formed from a plurality of graphite particles capable of inserting and extracting lithium ions,
After irradiating the carbon material with 28 kHz ultrasonic waves at an output of 60 W for 5 minutes, Q _5min (%) which is the number frequency (%) of the particle diameter of 5 μm or less measured by a flow type particle image analyzer,
After irradiating a carbon material with 28 kHz ultrasonic waves at an output of 60 W for 1 minute, D50 (μm), which is a volume-based median diameter measured by a laser diffraction / scattering method,
Formula (1): Q _5min (%) / D50 (μm) ≦ 3.5
A carbon material characterized by satisfying The carbon material for nonaqueous secondary batteries according to claim 1, wherein Q _5min (%) is 40% or less. The carbon material is heated from room temperature to 1000 ° C., and the total amount of desorbed CO and desorbed CO ₂ measured by a pyrolysis mass spectrometer (TPD-MS) is 125 μmol / g or less. The carbon material for non-aqueous secondary batteries described in 1.   The carbon material is heated from room temperature to 1000 ° C., and the amount of desorbed CO measured by a pyrolysis mass spectrometer (TPD-MS) is 100 μmol / g or less, according to claim 1. Carbon material for non-aqueous secondary batteries. The carbon material is heated from room temperature to 1000 ° C., and the amount of desorbed CO ₂ measured by a pyrolysis mass spectrometer (TPD-MS) is 25 μmol / g or less. Carbon material for non-aqueous secondary batteries. The carbon material for nonaqueous secondary batteries according to any one of claims 1 to 5, wherein the tap density is 0.7 g / cm ³ or more and 1.3 g / cm ³ or less.   The carbon material for nonaqueous secondary batteries according to any one of claims 1 to 6, wherein the average circularity is 0.86 or more. BET specific surface area of ^2m 2 / g or more and ^{30 m} 2 / g or less, a non-aqueous secondary battery carbon material according to any one of claims 1 to 7.   The carbon material for nonaqueous secondary batteries according to any one of claims 1 to 8, wherein a volume-based median diameter (D50) is 1 µm or more and 50 µm or less.   The carbon material for a non-aqueous secondary battery according to any one of claims 1 to 9, wherein Lc by an X-ray wide angle diffraction method is 90 nm or more and d002 is 0.337 nm or less.   The carbon material for nonaqueous secondary batteries according to claim 1, wherein the graphite particles contain natural graphite.   A composite carbon material for a non-aqueous secondary battery, wherein the carbon material according to any one of claims 1 to 11 is combined with a carbonaceous material.   It is a lithium ion secondary battery provided with the positive electrode and negative electrode which can occlude / release lithium ion, and an electrolyte, Comprising: A negative electrode is a carbon material for non-aqueous secondary batteries of any one of Claims 1-11 A nonaqueous secondary battery comprising the composite carbon material for a nonaqueous secondary battery according to claim 12.