JP6264925B2 - Carbon material, negative electrode for non-aqueous secondary battery, non-aqueous secondary battery, and method for producing carbon material - Google Patents

Description

  The present invention relates to a carbon material, a negative electrode for a non-aqueous secondary battery using the carbon material, a non-aqueous secondary battery including the negative electrode for the non-aqueous secondary battery, and a method for producing the carbon material. is there.

  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. Conventionally, high capacity of lithium ion secondary batteries has been widely studied, but in recent years, the demand for higher performance of lithium ion secondary batteries has been increasing. Therefore, there is a demand to achieve a long life.

  For lithium ion secondary batteries, it is known to use a carbon material such as graphite as the negative electrode active material. Among them, graphite having a high degree of graphitization, when used as an active material for a negative electrode for a lithium ion secondary battery, has a capacity close to 372 mAh / g, which is the theoretical capacity for lithium occlusion of graphite. Since it is excellent also in the property, it is known that it is preferable as an active material for negative electrodes. On the other hand, when the active material layer containing the negative electrode material is densified to increase the capacity, the destruction / deformation of the material increases the irreversible capacity of charge / discharge during the initial cycle, decreases the large current charge / discharge characteristics, reduces the cycle characteristics. There was a problem of decline.

  In addition, when the carbon material as described above is used as an active material for a negative electrode of a lithium ion secondary battery, usually, the surface of the carbon material is combined with a polymer compound used for a binder or the like and a non-aqueous electrolyte solution. A protective coating called SEI (Solid Electrolyte Interface) is formed by the reaction. It is known that SEI prevents contact between the carbon material and the electrolytic solution, suppresses decomposition of the electrolytic solution by the active carbon material, and maintains the chemical stability of the negative electrode surface.

  However, in a lithium ion secondary battery using a carbon material as an active material for a negative electrode, the charge / discharge irreversible capacity during the initial cycle increases due to the generation of SEI film and the generation of gas as a side reaction product. There was a problem that the capacity could not be increased. In addition, the formation of a stable SEI film increases the interfacial resistance of the negative electrode, which reduces the input / output characteristics of the battery.

  In order to solve the above problem, for example, in Patent Document 1, spheroidized natural graphite is produced by performing spheronization treatment (mechanical energy treatment) using natural graphite, and the spheroidized natural graphite is used as a core. A technique for forming graphite and coating amorphous carbon on the surface thereof has been developed. However, the spheroidized natural graphite disclosed in Patent Document 1 has a high capacity and good rapid charge / discharge characteristics, but excessive decomposition of the electrolyte occurs. Therefore, the initial irreversible capacity and charge / discharge cycle characteristics are low. Insufficient amount of side reaction product gas was generated, and further improvement was necessary.

  On the other hand, as a technique for suppressing excessive decomposition of an electrolytic solution, a method of coating a carbon material, which is an active material for a negative electrode, with a polymer or the like is known. For example, Patent Document 2 discloses carbon for the purpose of suppressing decomposition of a nonaqueous electrolytic solution and deposition of the decomposition product on the surface of the negative electrode and improving initial charge / discharge efficiency and charge / discharge cycle characteristics. A method of providing a coating layer made of an ion conductive polymer such as polyethylene oxide or a water-soluble polymer such as polyvinyl alcohol on the surface of the material is disclosed.

Further, for the purpose of improving the initial charge and discharge efficiency by suppressing the decomposition of the non-aqueous electrolyte, Patent Document 3 discloses that an aliphatic amino group having good adhesion to the surface of a carbon material such as polyallylamine as a carbon material. The method of attaching an organic polymer having a side chain to a side chain is disclosed in Patent Document 4 in which a water-soluble polymer is applied to spheroidized natural graphite having a surface oxygen functional group to improve adhesion to the water-soluble polymer. A method of attaching is disclosed. In Patent Document 5, for the purpose of improving initial efficiency and input / output characteristics, a polymer material (C-1) having high solubility in an electrolytic solution is attached to pores of 1 μm or less and further dissolved in an electrolytic solution. A method of attaching a polymer material (C-2) having a low property to a place different from C-1 is disclosed.

Japanese Patent No. 3534391 JP-A-11-129992 JP 2002-117851 A JP 2011-198710 A Japanese Patent No. 4967268

However, according to the study by the present inventors, the spheroidized natural graphite disclosed in Patent Document 1 has a high capacity and good rapid charge / discharge characteristics, but excessive decomposition of the nonaqueous electrolyte occurs. Therefore, the initial charge / discharge efficiency and charge / discharge cycle characteristics are insufficient, and the amount of side reaction product gas generated is large, and further improvement is required.
In addition, when the carbon material is coated with an ion conductive polymer or a water-soluble polymer disclosed in Patent Document 2, the adhesion to the carbon material is insufficient and the electrolyte solution is swellable. When such a carbon material is used as the negative electrode active material, initial charge / discharge efficiency, charge / discharge cycle characteristics, and stability are still insufficient.

  In the carbon material in which the polymer disclosed in Patent Document 3 and Patent Document 4 is attached to the carbon material, the initial charge / discharge efficiency and stability are improved by improving the adhesion between the polymer and the carbon material. Since the insertion and desorption sites of Li ions are excessively covered and the ionic conductivity of the polymer used is insufficient, it has been clarified that the low-temperature input / output characteristics are insufficient.

  In the technique described in Patent Document 5, by adding a polymer material (C-1) having high solubility in an electrolyte solution to pores of 1 μm or less, negative electrode interface resistance is reduced and input / output characteristics are improved. Although a certain effect was obtained, only the relatively large pores with a pore size of 1 μm are of interest, and attention is paid to pores in the mesopore region of about several nm corresponding to the Li ion insertion / desorption sites. As a result, the input / output characteristics were still insufficient. Furthermore, since C-1 has solubility in an electrolytic solution, the electrolytic solution comes into contact with the graphite surface, and initial charge / discharge efficiency, storage characteristics, and charge / discharge cycle characteristics are insufficient.

  The present invention has been made in view of the background art, and the problem is that the initial charge and discharge efficiency is sufficiently high, and has excellent input / output characteristics and high-temperature storage characteristics, during initial cycles and during high-temperature storage. The object is to provide a carbon material capable of obtaining a non-aqueous secondary battery with less gas generation, and as a result, to provide a high-performance non-aqueous secondary battery.

As a result of intensive studies to solve the above problems, the present inventors have occluded lithium ions.
A mesopore of 2 nm or more and 4 nm or less in a carbon material for a nonaqueous secondary battery negative electrode containing a releasable carbon material (A) (hereinafter also referred to as “carbon material (A)”) and an organic compound (B). The specific organic compound (B) is attached so that the ratio (SAa / SAb) of the surface area derived from the surface area (SAa) and the surface area derived from the mesopore diameter of 4 nm to 35 nm (SAa / SAb) falls within a specific low value range. Therefore, it is possible to obtain a non-aqueous secondary battery negative electrode material having high charge / discharge efficiency at the initial cycle, excellent input / output characteristics, high temperature storage characteristics, and low gas generation during the initial cycle and high temperature storage. As a result, the present invention has been completed.

The reason why the carbon material according to the present invention has the above effect is considered as follows.
That is, among the pores existing on the surface of the carbon material (A), the mesopores of 2 nm or more and 4 nm or less greatly contribute to the insertion / desorption reaction of Li ions in charge / discharge, and at the same time, to the decomposition reaction of the electrolytic solution. The contribution is also considered to be large. By selectively protecting the surface of the mesopores of 2 nm or more and 4 nm or less with the organic compound (B) (“SAa / SAb” is in a specific low value range), the decomposition reaction of the electrolytic solution can be effectively performed. It is considered that the effects of suppressing and improving the initial charge / discharge efficiency and reducing the gas generation could be remarkably exhibited.

Furthermore, the desolvation of lithium ions solvated with the electrolytic solution is promoted, and the reductive decomposition of the electrolytic solution is suppressed, thereby further improving the effect of improving the initial charge / discharge efficiency. On the surface of the mesopores of 2 nm or more and 4 nm or less It is considered that good low temperature input / output characteristics could be obtained by promoting lithium ion diffusion in the formed protective coating.
That is, the gist of the present invention is as follows.
<1> A carbon material (C) containing a carbon material (A) and an organic compound (B), and a mesopore surface area ratio (SAa / SAb) represented by the following formula (1) is 0.63 or less. A carbon material (C) for a non-aqueous secondary battery, characterized in that:

Formula (1) SAa / SAb = Mesopore surface area of 2 nm or more and 4 nm or less obtained by nitrogen adsorption method / Mesopore surface area of 4 nm or more and 35 nm or less obtained by nitrogen adsorption method <2> Mesopores of 35 nm or less obtained by nitrogen adsorption method The carbon material (C) for nonaqueous secondary batteries according to <1>, wherein the pore volume is 0.007 ml / g or more.
<3> The carbon material (C) for nonaqueous secondary batteries according to <1> or <2>, wherein the carbon material (A) is spheroidized natural graphite.
<4> The mesopore volume of 35 nm or less determined by the nitrogen adsorption method of the carbon material (A) is 0.007 ml / g or more, and any one of <1> to <3> The carbon material for nonaqueous secondary batteries as described (C).
<5> The non-aqueous secondary according to any one of <1> to <4>, wherein the organic compound (B) has a basic group and a group having a lithium ion coordination property. Carbon material for battery (C).
<6> The carbon material for nonaqueous secondary batteries (C) according to <5>, wherein the organic compound (B) has a π-conjugated structure.
<7> A carbon material (A) capable of occluding and releasing lithium ions and a carbon material for a non-aqueous secondary battery negative electrode containing an organic compound (B),
Step (1): Step of mixing carbon material (A) and organic compound (B) in a solvent Step (2): A step of stirring and drying the mixture obtained in Step (1) The manufacturing method of the carbon material (C) for non-aqueous secondary batteries.
<8> The carbon material (C) for a non-aqueous secondary battery according to <7>, wherein the organic compound (B) has a basic group and a group having a lithium ion coordination property. Method.
<9> In the step (2), using a stirrer having a stirring blade in a fixed container, the stirring blade is stirred and mixed at a peripheral speed of 0.01 m / s to 40 m / s. The method for producing a carbon material for a nonaqueous secondary battery (C) according to <7> or <8>, wherein the carbon material (C) is dried.
<10> A current collector and an active material layer formed on the current collector, wherein the active material layer is a non-aqueous secondary material according to any one of <1> to <6> A negative electrode for a non-aqueous secondary battery, comprising a carbon material (C) for a battery.
<11> A nonaqueous secondary battery comprising a positive electrode and a negative electrode capable of inserting and extracting lithium ions, and an electrolyte, wherein the negative electrode is the negative electrode for a nonaqueous secondary battery according to <10>. Next battery.

  By using the carbon material of the present invention as a negative electrode active material for a non-aqueous secondary battery, a non-aqueous secondary battery having a high capacity, excellent cycle retention, high-temperature storage characteristics, and low gas generation amount can be obtained. Can be provided.

  Hereinafter, the contents of the present invention will be described in detail. The description of the invention constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these forms unless it exceeds the gist.

<Carbon material (A)>
The carbon material (A) of the present invention is not particularly limited as long as it is a carbon material capable of occluding and releasing lithium ions, and examples thereof include graphite, amorphous carbon, and a carbonaceous material having a low graphitization degree. Among them, graphite is readily available commercially, theoretically has a high charge / discharge capacity of 372 mAh / g, and even at a higher current density than when other negative electrode active materials are used. This is preferable because the effect of improving the charge / discharge characteristics is great. As graphite, those having few impurities are preferable, and they can be used after being subjected to various known purification treatments, if necessary. Examples of the type of graphite include natural graphite and artificial graphite, and natural graphite is more preferable.

Further, a carbonaceous material such as amorphous carbon or graphitized material may be used. In this invention, these can be used individually or in combination of 2 or more types.
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 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.
Examples of natural graphite include highly purified flaky graphite and spheroidized graphite. Among these, natural graphite subjected to spheroidizing treatment is more preferable from the viewpoint of particle filling properties and charge / discharge load characteristics.

As an apparatus used for the spheronization treatment, for example, an apparatus that repeatedly gives mechanical effects such as compression, friction, shearing force, etc. including the interaction of graphite carbonaceous particles, 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 action such as impact compression, friction, shearing force, etc. is applied to the carbon material introduced inside. An apparatus that provides a surface treatment is preferable. Moreover, it is preferable to have a mechanism that repeatedly gives mechanical action by circulating graphite.

As a preferable apparatus for giving a mechanical action to the carbon material, for example, a hybridization system (manufactured by Nara Machinery Co., Ltd.), a kryptron (manufactured by Earth Technica), a CF mill (manufactured by Ube Industries), a mechano-fusion system (Hosokawa Micron) And theta composer (manufactured by Deoksugaku Kosakusha). Among these, a hybridization system manufactured by Nara Machinery Co., Ltd. is preferable.

When processing using the apparatus, for example, the peripheral speed of the rotating rotor is preferably 30 to 100 m / sec, more preferably 40 to 100 m / sec, and particularly preferably 50 to 100 m / sec. Further, the treatment that gives a mechanical action to the carbon material can be performed simply by passing graphite. However, it is preferable that the graphite is circulated or retained in the apparatus for 30 seconds or more, and is preferably treated for 1 minute or more in the apparatus. More preferably, the treatment is performed by circulation or retention.
Examples of the amorphous carbon include particles obtained by baking a bulk mesophase and particles obtained by infusibilizing and baking a carbon precursor.

  Examples of the carbonaceous material having a low graphitization degree include those obtained by firing an organic material at a temperature of usually less than 2500 ° C. Organic substances include coal-based heavy oil such as coal tar pitch and dry distillation liquefied oil; straight-run heavy oil such as atmospheric residual oil and vacuum residual oil; ethylene tar produced as a by-product 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.

Depending on the degree of graphitization of the carbonaceous material, the firing temperature can be 600 ° C or higher, preferably 900 ° C or higher, more preferably 950 ° C or higher, and lower than 2500 ° C. Preferably it is 2000 degrees C or less, More preferably, it is the range of 1400 degrees C or less.
At the time of baking, 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.

As the carbon material (A), particles obtained by coating the above natural graphite or artificial graphite with amorphous carbon and / or a graphite material having a low degree of graphitization can also be used. Moreover, an oxide and other metals may be included. Other metals include metals that can be alloyed with Li, such as Sn, Si, Al, Bi.
The carbon material which comprises a carbon material (A) can also be used in combination with 1 type, or 2 or more types of another carbon material.

<Physical properties of carbon material (A)>
-Mesopore volume, mesopore surface area In the carbon material of the present invention, the mesopore volume and the mesopore surface area are measured by the BJH method analysis using the adsorption isotherm measured by the nitrogen adsorption method, And the mesopore surface area. The mesopore surface area by BJH method area analysis was calculated by accumulating the side area assuming that the mesopore was cylindrical.

-Mesopore volume in the range of 35 nm or less The mesopore volume in the range of 35 nm or less is preferably 0.001 mL / g or more, more preferably 0.007 mL / g or more, still more preferably 0.008 mL / g or more, particularly preferably Is not less than 0.009 mL / g, most preferably not less than 0.01 mL / g, preferably not more than 0.1 mL / g, more preferably not more than 0.05 mL / g, still more preferably 0.8. It is 02 mL / g or less.

  If it is within the above range, the gap that allows the nonaqueous electrolyte to enter can be adjusted appropriately, so that lithium ions can be smoothly inserted and desorbed when rapidly charged and discharged, and the low-temperature input / output characteristics are improved. In addition, the deterioration of cycle characteristics due to precipitation of lithium metal can be further suppressed. Furthermore, excessive decomposition of the electrolytic solution can be suppressed, and a decrease in initial efficiency and an increase in the amount of gas generated can be further suppressed.

-Mesopore surface area (SAa) in the range of 2 nm to 4 nm, mesopore surface area (SAb) in the range of 4 nm to 35 nm, mesopore surface area ratio (SAa / SAb)
Mesopore surface area in the range of 2nm~4nm (SAa) is preferably 0.1 m ² / g or more, more preferably 0.5 m ² / g or more, more preferably ^{1 m} 2 / g or more, particularly preferably ^2m 2 / g or more, most preferably 2.2 m ² / g or more, preferably 10 m ² / g or less, more preferably 5 m ² / g or less, still more preferably 4 m ² / g or less, particularly preferably Is 3 m ² / g or less.

Mesopore surface area in the range of 4nm~35nm (SAb) is preferably 0.1 m ² / g or more, more preferably 0.5 m ² / g or more, more preferably ^{1 m} 2 / g or more, particularly preferably ^2m 2 / g or more, most preferably 2.4 m ² / g or more, preferably 10 m ² / g or less, more preferably 5 m ² / g or less, still more preferably 4 m ² / g or less, particularly preferably. Is 3 m ² / g or less.

The mesopore surface area ratio (SAa / SAb) is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more, particularly preferably 0.7 or more, and most preferably 0.8. In addition, it is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.2 or less, and particularly preferably 1 or less.
The mesopore surface area (SAa) in the range of 2 nm to 4 nm correlates with the amount of the active end face from which Li ions can be inserted and desorbed, and it is considered that the decomposition reaction activity of the electrolyte is higher. On the other hand, it is considered that the mesopore surface area (SAb) in the range of 4 nm to 35 nm correlates with the amount of the basal plane having a small contribution to the insertion / desorption of Li ions.

  When the mesopore surface area (SAa) in the range of 2 nm to 4 nm is within the above range, the insertion / desorption site of the Li ion of the carbon material is not reduced so much, so the Li ion can be smoothly inserted into the carbon material. -Since desorption can be performed, there is a tendency that deterioration in low-temperature input / output characteristics can be further suppressed. Moreover, since excessive decomposition | disassembly of electrolyte solution can be suppressed, the fall of initial efficiency and the increase in the amount of gas generation can be suppressed more.

  In addition, when the mesopore surface area (SAb) in the range of 4 nm to 35 nm is within the above range, the graphite crystallite is not so small, and at the same time, the mesopore surface area (SAa) in the range of 2 nm to 4 nm is significantly reduced. Therefore, it is possible to further suppress the capacity reduction and the low temperature input / output characteristics. Furthermore, since excessive decomposition of the electrolytic solution can be suppressed, a decrease in initial efficiency and an increase in the amount of gas generated can be further suppressed.

  When the mesopore surface area ratio (SAa / SAb) is within the above range, the ratio of Li ion insertion / desorption sites in the carbon material is unlikely to be low, and the smooth insertion of Li ions into the carbon material is possible. Since desorption is possible, a decrease in low-temperature input / output characteristics can be further suppressed. Moreover, since excessive decomposition | disassembly of electrolyte solution can be suppressed, the fall of initial efficiency and the increase in the amount of gas generation can be suppressed more.

-Surface functional group amount O / C value An X-ray photoelectron spectrometer (for example, ESCA manufactured by ULVAC-PHI) is used as an X-ray photoelectron spectroscopy measurement (XPS), and the surface of the object to be measured (here, graphite material) is flat. The sample is placed on the sample stage, and the spectrum of C1s (280 to 300 eV) and O1s (525 to 545 eV) is measured by multiplex measurement using the Kα ray of aluminum as an X-ray source. The obtained C1s peak top is corrected to be 284.3 eV, the peak areas of the C1s and O1s spectra are obtained, and the device sensitivity coefficient is multiplied to calculate the surface atomic concentrations of C and O, respectively. The obtained atomic concentration ratio O / C of O and C (O atomic concentration / C atomic concentration) is defined as the surface functional group amount O / C value of the carbon material.
The O / C value obtained from XPS is preferably 0.8 or more, more preferably 1 or more, still more preferably 1.5 or more, particularly preferably 2 or more, preferably 8 or less, more preferably 4 or less, still more preferably Is 3.5 or less, particularly preferably 3 or less.

-Volume-based average particle size (average particle size d50)
The volume-based average particle diameter (also referred to as “average particle diameter d50”) of the carbon material of the present invention is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and particularly preferably 15 μm or more. The average particle diameter d50 is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 35 μm or less, and particularly preferably 31 μm or less. If the average particle size d50 is too small, the non-aqueous secondary battery obtained using the carbon material tends to increase the irreversible capacity and cause a loss of initial battery capacity. On the other hand, if the average particle size d50 is too large, slurry coating may occur. May cause inconveniences such as line drawing, deterioration of high current density charge / discharge characteristics, and deterioration of low temperature input / output characteristics.

  In this specification, the average particle size d50 is obtained by adding 10 mL of a 0.2 mass% aqueous solution of polyoxyethylene sorbitan monolaurate (for example, Tween 20 (registered trademark)) as a surfactant to a carbon material. 0.01 g was suspended, and this was introduced as a measurement sample into a commercially available laser diffraction / scattering particle size distribution measurement device (for example, LA-920 manufactured by HORIBA), and the measurement sample was irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute. After that, the volume is defined as a volume-based median diameter measured by the measuring device.

-Circularity The carbon material of the present invention has a circularity of 0.88 or more, preferably 0.90 or more, more preferably 0.91 or more. The circularity is preferably 1 or less, more preferably 0.98 or less, and still more preferably 0.97 or less. When the circularity is within the above range, the high current density charge / discharge characteristics of the non-aqueous secondary battery tend to be suppressed. 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)
As the circularity value, for example, a flow type particle image analyzer (for example, FPIA manufactured by Sysmex Industrial Co., Ltd.) is used, and about 0.2 g of a sample (carbon material) is added to polyoxyethylene (20) sorbitan as a surfactant. After dispersing in a 0.2% by weight monolaurate aqueous solution (about 50 mL) and irradiating the dispersion with an ultrasonic wave of 28 kHz for 1 minute at an output of 60 W, the detection range is specified as 0.6 to 400 μm, and the particle size is The value measured for particles in the range of 1.5-40 μm is used.

  A method for improving the degree of circularity is not particularly limited, but a spheroidized sphere is preferable because the shape of the interparticle voids when the negative electrode is formed is preferable. Examples of spheroidizing treatment include a method of mechanically approaching a sphere by applying a shearing force and a compressive force, and a mechanical / physical treatment in which a plurality of carbon material fine particles are granulated by the adhesive force of the binder or the particles themselves. Methods and the like.

-Tap density The tap density of the carbon material of the present invention is preferably 0.7 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, still more preferably 0.85 g / cm ³ or more, particularly preferably 0.9 g. / Cm ³ or more, most preferably 0.95 g / cm ³ or more, preferably 1.3 g / cm ³ or less, more preferably 1.2 g / cm ³ or less, still more preferably 1.1 g / cm ^3. It is as follows.

When the tap density is within the above range, the processability such as streaking during the production of the electrode plate is good, and the high-speed charge / discharge characteristics are excellent. In addition, since the carbon density in the particles is difficult to increase, the rolling property is good and the high-density negative electrode sheet tends to be easily formed.
The tap density was filled into the cell by dropping the carbon material of the present invention through a sieve having a mesh size of 300 μm into a cylindrical tap cell having a diameter of 1.6 cm and a volume capacity of 20 cm ³ using a powder density measuring device. After that, a tap having a stroke length of 10 mm is performed 1000 times and defined as the density obtained from the volume at that time and the mass of the sample.

-X-ray parameter The d value (interlayer distance) of the lattice plane (002 plane) of the carbon material of the present invention determined by X-ray diffraction by the Gakushin method is preferably 0.335 nm or more and less than 0.340 nm. Here, the d value is more preferably 0.339 nm or less, and still more preferably 0.337 nm or less. When the d002 value is within the above range, the initial irreversible capacity tends to suppress an increase because the crystallinity of graphite is high. Here, 0.335 nm is a theoretical value of graphite.
The crystallite size (Lc) of the carbon material determined by X-ray diffraction by the Gakushin method is preferably 1.5 nm or more, more preferably 3.0 nm or more. Within the above range, the crystallinity is not too low, and the reversible capacity is difficult to decrease when a non-aqueous secondary battery is obtained. The lower limit of Lc is the theoretical value of graphite.

-Ash content The ash content contained in the carbon material of the present invention 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 of the carbon material. It is. Moreover, it is preferable that the minimum of ash content is 1 ppm or more.
When the ash content is within the above range, when a non-aqueous secondary battery is used, deterioration of battery performance due to the reaction between the carbon material and the electrolyte during charge / discharge can be suppressed to a negligible level. 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.

・ BET specific surface area (SA)
The specific surface area (SA) measured by the BET method of the carbon material of the present invention is preferably 3 m ² / g or more, more preferably 4 m ² / g or more, still more preferably 4.5 m ² / g or more, and particularly preferably 5 .1 m ² / g or more. Moreover, Preferably it is 11 m < ² > / g or less, More preferably, it is 9 m < ² > / g or less, More preferably, it is 8 m < ² > / g or less.

When the specific surface area is within the above range, it is possible to sufficiently secure the portion where Li enters and exits, so the high speed charge / discharge characteristics output characteristics are excellent, and the activity of the active material against the electrolytic solution can be moderately suppressed. However, the high-capacity battery tends to be manufactured.
In addition, when a negative electrode is formed using a carbon material, an increase in reactivity with the electrolytic solution can be suppressed and gas generation can be suppressed, so that a preferable nonaqueous secondary battery can be provided.

The BET specific surface area was measured using a surface area meter (for example, a specific surface area measuring device “Gemini 2360” manufactured by Shimadzu Corp.), preliminarily dried at 100 ° C. for 3 hours in a nitrogen stream on a carbon material sample, and then liquid nitrogen. It is defined as a value measured by a nitrogen adsorption BET 6-point method using a gas flow method using a nitrogen-helium mixed gas that is cooled to a temperature and adjusted accurately so that the relative pressure value of nitrogen with respect to atmospheric pressure is 0.3.

-Pore volume in the range of 10 nm to 1000 nm In the carbon material of the present invention, the pore volume in the range of 10 nm to 1000 nm is a value measured using a mercury intrusion method (mercury porosimetry), preferably 0.05 mL. / G or more, more preferably 0.07 mL / g or more, further preferably 0.1 mL / g or more, preferably 0.3 mL / g or less, more preferably 0.28 mL / g or less, Preferably it is 0.25 mL / g or less.

  When the pore volume in the range of 10 nm to 1000 nm is within the above range, it is difficult to reduce voids into which the non-aqueous electrolyte can enter, and lithium ion insertion / desorption is not in time when rapid charge / discharge is performed. The tendency for lithium metal to precipitate and the cycle characteristics to deteriorate can be further avoided. Furthermore, the tendency that the binder becomes difficult to be absorbed in the gap during the electrode plate production and the electrode plate strength and the initial efficiency are reduced accordingly can be avoided.

The total pore volume of the carbon material of the present invention is preferably 0.1 mL / g or more, more preferably 0.2 mL / g or more, still more preferably 0.25 mL / g or more, and particularly preferably 0.5 mL / g. g or more. The total pore volume is preferably 10 mL / g or less, more preferably 5 mL / g or less, still more preferably 2 mL / g or less, and particularly preferably 1 mL / g or less.
When the total pore volume is within the above range, it is not necessary to make the amount of the binder excessive when forming the electrode plate, and it is easy to obtain the effect of dispersing the thickener or the binder when forming the electrode plate.

The average pore diameter of the carbon material of the present invention is preferably 0.03 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more, and particularly preferably 0.5 μm or more. The average pore diameter is preferably 80 μm or less, more preferably 50 μm or less, and still more preferably 20 μm or less.
When the average pore diameter is within the above range, it is not necessary to make the amount of the binder excessive when forming the electrode plate, and it tends to avoid deterioration of the high current density charge / discharge characteristics of the battery.

As the mercury porosimetry apparatus, a mercury porosimeter (Autopore 9520: manufactured by Micromeritex Corporation) can be used. A sample (carbon material) is weighed to a value of about 0.2 g, enclosed in a powder cell, and pretreated by degassing at room temperature and under vacuum (50 μmHg or less) for 10 minutes.
Subsequently, the pressure is reduced to 4 psia (about 28 kPa), mercury is introduced into the cell, the pressure is increased stepwise from 4 psia (about 28 kPa) to 40000 psia (about 280 MPa), and then the pressure is reduced to 25 psia (about 170 kPa).

The number of steps at the time of pressure increase is 80 points or more, and the mercury intrusion amount is measured after an equilibration time of 10 seconds in each step. The pore distribution is calculated from the mercury intrusion curve thus obtained using the Washburn equation.
Note that the surface tension (γ) of mercury is calculated as 485 dyne / cm and the contact angle (ψ) is 140 °. The average pore diameter is defined as the pore diameter when the cumulative pore volume is 50%.

True density The true density of the carbon material of the present invention is preferably 1.9 g / cm ³ or more, more preferably 2 g / cm 2.
cm ³ or more, more preferably 2.1 g / cm ³ or more, particularly preferably 2.2 g / cm ³ or more, the upper limit is 2.26 g / cm ^3. The upper limit is the theoretical value of graphite. When the true density is within the above range, the crystallinity of the carbon is not too low, and an increase in the initial irreversible capacity in the case of a non-aqueous secondary battery tends to be suppressed.

Aspect ratio The aspect ratio of the carbon material of the present invention in a powder state is theoretically 1 or more, preferably 1.1 or more, more preferably 1.2 or more. The aspect ratio is preferably 10 or less, more preferably 8 or less, and still more preferably 5 or less.
When the aspect ratio is within the above range, streaking of the slurry containing the carbon material (negative electrode forming material) hardly occurs at the time of forming the electrode plate, and a uniform coated surface is obtained, and high current density charge / discharge of the non-aqueous secondary battery is obtained. There is a tendency to avoid deterioration of characteristics.

  The aspect ratio is expressed as A / B when the longest diameter A of the carbon material particles when observed three-dimensionally and the shortest diameter B among the diameters orthogonal to the carbon material particles. The carbon material particles are observed with a scanning electron microscope capable of magnifying observation. Arbitrary 50 carbon material particles fixed to the end face of a metal having a thickness of 50 microns or less are selected, and the stage on which the sample is fixed is rotated and tilted to measure A and B, and A / B Find the average value of.

・ Maximum particle size dmax
The maximum particle diameter dmax of the carbon material of the present invention is preferably 200 μm or less, more preferably 150 μm or less, still more preferably 120 μm or less, particularly preferably 100 μm or less, and most preferably 80 μm or less. When dmax is within the above range, the occurrence of process inconveniences such as line drawing tends to be suppressed.
The maximum particle size is defined as the value of the largest particle size at which particles are measured in the particle size distribution obtained when measuring the average particle size d50.

-Raman R value The value of the Raman R value of the carbon material of the present invention is preferably 0.1 or more, more preferably 0.15 or more, and still more preferably 0.2 or more. The Raman R value is preferably 0.6 or less, more preferably 0.5 or less, and still more preferably 0.4 or less.
Incidentally, 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, the intensity Defined as the ratio (I _B / I _A ).
Incidentally, the scope of 1580～1620Cm ^-1 A "1580cm around ^-1" in the present specification, "1360cm around ^-1" refers to the range of 1350 ^-1.

When the Raman R value is within the above range, the crystallinity of the carbon material particle surface is unlikely to be high, and when the density is increased, the crystal is difficult to be oriented in a direction parallel to the negative electrode plate, and a tendency to avoid deterioration of load characteristics is avoided. It is in. Furthermore, the crystal on the particle surface is not easily disturbed, and the increase in reactivity with the electrolyte solution of the negative electrode is suppressed, and the decrease in charge / discharge efficiency of the nonaqueous secondary battery and the increase in gas generation 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)

DBP oil absorption The DBP (dibutyl phthalate) oil absorption of the carbon material of the present invention is preferably 65 ml / 100 g or less, more preferably 62 ml / 1 BR> O 0 g or less, more preferably 60 ml / 100 g or less, particularly preferably 57 ml. / 100g or less. The DBP oil absorption is preferably 30 ml / 100 g or more, more preferably 40 ml / 100 g or more.

If the DBP oil absorption amount is within the above range, it means that the progress of spheroidization of the carbon material is sufficient, and there is a tendency that streaking is difficult to occur during the application of the slurry containing the carbon material. However, since the pore structure exists, the reaction surface tends to be prevented from lowering.
The DBP oil absorption amount is defined as a measured value when 40 g of a measurement material (carbon material) is added, a dropping speed is 4 ml / min, a rotation speed is 125 rpm, and a set torque is 500 N · m, in accordance with JIS K6217. For the measurement, for example, Absorbometer E type manufactured by Brabender can be used.

・ Average particle diameter d10
The particle size (d10) corresponding to 10% cumulative from the small particle side of the particle size measured on a volume basis of the carbon material of the present invention is preferably 30 μm or less, more preferably 20 μm or less, still more preferably 17 μm or less, preferably It is 1 μm or more, more preferably 5 μm or more, further preferably 10 μm or more, particularly preferably 11 μm or more, and most preferably 13 μm or more.

When d10 is within the above range, the tendency of the particles to agglomerate does not become too strong, and it is possible to avoid the occurrence of process inconveniences such as an increase in slurry viscosity, a decrease in electrode strength and a decrease in initial charge / discharge efficiency in nonaqueous secondary batteries. In addition, the high current density charge / discharge characteristics and the low temperature input / output characteristics tend to be avoided.
d10 is defined as a value obtained by integrating 10% from a particle size having a small particle frequency% in the particle size distribution obtained when measuring the average particle size d50.

・ Average particle size d90
The particle size (d90) corresponding to 90% of the particle size measured on the volume basis of the carbon material of the present invention is preferably 100 μm or less, more preferably 70 μm or less, still more preferably 60 μm or less, and even more. The thickness is preferably 50 μm or less, particularly preferably 45 μm or less, most preferably 42 μm or less, preferably 20 μm or more, more preferably 26 μm or more, still more preferably 30 μm or more, and particularly preferably 34 μm or more.

When d90 is within the above range, it is possible to avoid a decrease in electrode strength and a decrease in initial charge / discharge efficiency in a non-aqueous secondary battery, generation of process inconveniences such as striation during application of slurry, and high current density charge / discharge characteristics. There is a tendency to avoid the decrease in the temperature and the low-temperature input / output characteristics.
d90 is defined as a value in which the frequency% of particles is 90% integrated from a small particle size in the particle size distribution obtained when measuring the average particle size d50.

<Organic compound (B)>
As the organic compound (B) of the present invention, those having at least a basic group or a group having a lithium ion coordinating group are preferable in order to highly selectively modify a mesopore of 2 nm or more and 4 nm or less. . Thereby, the desolvation of lithium ions solvated with the electrolytic solution is promoted, and the reductive decomposition of the electrolytic solution is suppressed, thereby further improving the effect of improving the initial charge / discharge efficiency, and the surface of the mesopores of 2 nm or more and 4 nm or less It is believed that good low-temperature input / output characteristics can be obtained by promoting the diffusion of lithium ions in the protective film formed on the substrate.

Further, the organic compound (B) may be a single compound or two or more kinds of compounds may be mixed.
The organic compound (B) of the present invention more preferably has a π-conjugated structure. Also,
The organic compound (B) of the present invention preferably has at least one structure (S) selected from the group consisting of a graft structure, a star structure, and a three-dimensional network structure.

  The organic compound (B) is non-aqueous electrolytic because the resistance of the negative electrode active material for the negative electrode of the non-aqueous secondary battery of the present invention to the electrolytic solution is improved and the coating of the negative electrode active material (A) layer is difficult to elute into the electrolytic solution. What is hardly soluble in a liquid is more preferable. In addition, when it is immersed for 24 hours in the solvent which mixed the organic compound (B) with ethyl carbonate and ethyl methyl carbonate by the volume ratio of 3: 7 when it is hardly soluble in a non-aqueous electrolyte, the dry weight reduction rate before and behind immersion Means 10% by mass or less.

  The organic compound that is hardly soluble in the non-aqueous electrolyte preferably has an ionic group. An ionic group is a group that can generate an anion or a cation in water. Examples of the group that can generate an anion include a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, and these groups. Salt. Examples of the salt include lithium salt, sodium salt, potassium salt and the like. Examples of the group capable of generating a cation include a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, and salts thereof. Examples of the salt include acetate, hydrochloride, sulfate, amide sulfate, ammonium salt and the like. Among these, from the viewpoint of initial irreversible capacity in the case of a non-aqueous secondary battery, a sulfonic acid group and its lithium salt or sodium salt, and a primary amino group are preferable.

  The electrical conductivity of the organic compound (B) at 25 ° C. is preferably 0.1 S / cm or less, more preferably 0.01 S / cm or less, and still more preferably 0.001 S / cm or less. Moreover, it is usually larger than 0 S / cm. The surface of the organic compound (B) contained in the carbon material (C) for non-aqueous secondary batteries because the organic compound (B) is a low conductivity material having an electrical conductivity at 25 ° C. of 0.1 S / cm or less. It is possible to suppress the electrolytic solution from being reduced and decomposed. When the electrical conductivity is too large, an excessive decomposition reaction of the electrolytic solution occurs, which may lead to a decrease in initial charge / discharge efficiency, an increase in gas generation, and a decrease in cycle characteristics.

For example, the electrical conductivity is obtained by film formation on a glass substrate by spin coater film formation or drop cast film formation, and the film thickness is multiplied by the surface resistance measured by the four-terminal method. It can be calculated from the reciprocal of the obtained value. The film thickness can be measured with a KLA step, surface roughness and fine shape measuring device, Tencor α-step type, and the surface resistance value by a four-terminal method can be measured with a Loresta GP MCP-T610 type manufactured by Mitsubishi Chemical Analytech.

In the case of a single compound, the organic compound (B) is composed of a single molecule having both a basic group and a group having a lithium ion coordination property in the molecule, preferably a base in the molecule. And a single molecule having a ionic conjugated structure and a lithium ion coordination group.
The molecule has at least one structure (S) selected from the group consisting of a graft structure, a star structure, and a three-dimensional network structure.

The organic compound (B) preferably takes the structure (S) by combining two or more organic compounds. Here, as an example of compounding, gelation can be mentioned.
The single compound includes a compound having a basic group (hereinafter sometimes referred to as an organic compound (B1)) and a compound having a lithium ion coordinating group (hereinafter referred to as an organic compound (B2)). A reaction product (hereinafter sometimes referred to as a reaction product (B1-B2)), and preferably an organic compound (B1), an organic compound (B2), and A reaction product with a compound having a π-conjugated structure (hereinafter may be referred to as an organic compound (B3)) (hereinafter may be referred to as a reaction product (B1-B2-B3)).

The single compound described above may be a low molecular compound or a high molecular compound. However, from the viewpoint of effectively suppressing gas generation, the single compound is referred to as a high molecular compound (polymer (b ′)). It is preferable that
The weight average molecular weight when the organic compound (B) is the polymer (b ′) is not particularly limited, but is preferably 500 or more, more preferably 1000 or more, still more preferably 2000 or more, and particularly preferably 2500 or more. On the other hand, the weight average molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 300,000 or less, and particularly preferably 200,000 or less.

  In the present specification, the weight average molecular weight is a weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as the solvent, or the solvent is aqueous or N, N-dimethylformamide. It is a weight average molecular weight in terms of standard polyethylene glycol measured by GPC of (DMF) or dimethyl sulfoxide (DMSO).

  Further, when two or more kinds of compounds are mixed as the organic compound (B), the organic compound (B) is 1) a mixture containing the organic compound (B1) and the organic compound (B2); 2) the organic compound ( B1), mixture containing organic compound (B2) and organic compound (B3); 3) mixture containing reaction product (B1-B2) and organic compound (B3); 4) organic compound (B1) and organic compound (B3) reaction product (hereinafter sometimes referred to as reaction product (B1-B3)) and organic compound (B2); 5) organic compound (B2) and organic compound (B3) ) And a reaction product (hereinafter also referred to as reaction product (B2-B3)) and organic compound (B1); 6) reaction product (B1-B3) and reaction product A mixture containing (B2-B3); ) Mixture containing reaction product (B1-B2) and reaction product (B2-B3); 8) Mixture containing reaction product (B1-B2) and reaction product (B1-B3); 9) Reaction Mixture containing product (B1-B2) and organic compound (B1); 10) Mixture containing reaction product (B1-B2) and organic compound (B2); 11) Reaction product (B1-B2) A mixture containing the organic compound (B1) and the organic compound (B2); 12) In any one of the above 9) to 11), a mixture further containing the organic compound (B3);

In the specification of the present application, the mixture of the organic compound (B1) and the organic compound (B2) includes the organic compound (B1) and the organic compound (B2), respectively, in the non-aqueous secondary battery negative electrode active material. It is not always necessary to be mixed in the production process of the non-aqueous secondary battery negative electrode active material.
Even when the mixture is used as the main organic compound (B), the organic compounds in the mixture may react with each other in producing the active material of the present invention. In that case, the content ratio of the mixture of the organic compound and the reaction product in the organic compound (B) is preferably a mixture with respect to the total amount of the organic compound (B) (content relative to the active material (A)). It is 50 mass% or more, More preferably, it is 80 mass% or more, More preferably, it is 90 mass% or more, Most preferably, it is 99 mass% or more.

The same applies when the organic compound (B3) and / or various reaction products are mixed.
For example, when the reaction product (B1-B2) of the organic compound (B1) and the organic compound (B2) is used, the reaction product (B1-B2) is converted into the active material (A), the organic compound (B1), and the organic compound. After attaching (B2), a heating operation may be performed to react the organic compound (B1) and the organic compound (B2). Alternatively, the organic compound (B1) and the organic compound (B2) may be reacted to obtain a reaction product (B1-B2), which may then be attached to the active material (A).

The former is preferred from the viewpoints of adhesion to the active material (A) and suppression of surface activity.
The reaction temperature for obtaining the reaction product (B1-B2) can be 30 to 200 ° C. As the organic compound (B2) used in this temperature range, one having an epoxy group or a glycidyl group at the terminal is preferable. This epoxy group or glycidyl group corresponds to R ¹ and R ² in the following formula (1).

  The form of the organic compound (B) is preferably composed of a mixture or reaction product containing the organic compound (B1) and the organic compound (B2), and the organic compound (B1), the organic compound (B2), and the organic compound It is more preferable that it is comprised from the mixture or reaction product containing a compound (B3) from the reason which can ensure high adsorptivity to the active material (A) surface, lithium ion conductivity, and productivity.

Specifically, a mixture of the organic compound (B1), the organic compound (B2), and the organic compound (B3) is most preferable, and then the reaction product (B1-B2-B3) or the reaction product (B1-B2) And a mixture of organic compound (B3) are preferred, then a mixture of organic compound (B1) and organic compound (B2) is preferred, and then reaction product (B1-B2) is preferred.
In the case of the polymer (b) in which two or more kinds of compounds are mixed as the organic compound (B), the organic compound (B1) having a basic group corresponds to the polymer (b1) and has a lithium ion coordination property. The organic compound (B2) having a group having the group corresponds to the polymer (b2). The polymer (b1) and the polymer (b2) will be described later.

(1. Basic group)
The basic group in the organic compound (B) of the present invention acts on the functional group on the surface of the active material (A) and suppresses the activity on the surface of the active material (A). In addition, since the organic compound (B) has a basic group, the adsorptivity between the surface of the active material (A) and the organic compound (B) can be improved, so that the organic compound is formed on the active material (A). Since (B) can exist stably and elution can be suppressed, the effect which was excellent in the storage characteristic and cycling characteristics is shown.

  Moreover, since the adsorptivity with the mesopore surface in the range of 2 nm to 4 nm can be effectively improved, the mesopore surface in the range of 2 nm to 4 nm having a higher decomposition reaction activity with the electrolytic solution is effectively obtained. Can be protected. For this reason, the mesopore surface area (SAa) in the range of 2 nm to 4 nm can be efficiently reduced, and the mesopore surface area ratio (SAa / SAb) of the carbon material (C) for a non-aqueous secondary battery described later is specified. It is possible to be in the range. As a result, contact with the electrolytic solution can be effectively prevented, so that the decomposition reaction of the electrolytic solution can be effectively suppressed, and an excellent effect in improving initial efficiency and reducing the amount of gas generated is exhibited.

The basic group in the organic compound (B) of the present invention is defined as a group that donates an electron pair, and is not particularly limited as long as it satisfies this definition. For example, a primary amino group, Secondary amino group, tertiary amino group, and quaternary ammonium group may be mentioned.
Among these, a primary amino group, a secondary amino group, and a tertiary amino group are preferable, and a primary amino group and a secondary amino group are particularly preferable in terms of high adhesiveness or reactivity with the active material surface functional group.

The basic group in the organic compound (B) of the present invention is defined as a group that donates an electron pair, and is not particularly limited as long as it satisfies this definition. For example, a primary amino group, Secondary amino group, tertiary amino group, and quaternary ammonium group may be mentioned.
Hereinafter, the organic compound (B1) having a basic group will be described.
For example, examples of the organic compound (B1) include those having a unit derived from an ethylenically unsaturated group-containing amine. Specifically, what has a unit represented by following formula (2) or (3) is mentioned.

(In the formula ^(2), R 3 ~R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, ^{R 6} is absent atom single bond or a 1 to 6 carbon atoms An alkylene group, and R ⁷ and R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)

In (Equation ^{(3), R} 9 ~R ¹² are each independently hydrogen atom or an alkyl group having 1 to 6 carbon ^{atoms, R 13} and ^{R 14} are each independently, 1 to 6 carbon atoms R ¹⁵ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
The alkyl group having 1 to 6 carbon atoms in the formulas (2) and (3) may be linear or branched. For example, methyl, ethyl, propyl, isopropyl, butyl Group, isobutyl group, tert-butyl group, pentyl group, hexyl group, and the like, and a methyl group is preferable.

The alkylene group having 1 to 6 carbon atoms in the formulas (2) and (3) may be linear or branched, and examples thereof include a methylene group and an ethylene group, preferably methylene. It is a group.
In the formula (2), R ^{3 to} R ⁵ are each independently preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, and R ⁶ is preferably a single bond or a methylene group in which no atom exists. R ⁷ and R ⁸ are each independently preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

Among them, R ^{3 to} R ⁵ are all hydrogen atoms, R ⁶ is a single bond or a methylene group in which no atom is present, and R ⁷ and R ⁸ are hydrogen atoms, and the unit represented by the formula (2) Is more preferable. In the case where R ⁷ and R ⁸ are hydrogen atoms and the organic compound (B1) has a primary amino group, it is preferable because adhesion or reactivity with the surface of the active material (A) is high.
In the formula (3), R ^{9 to} R ¹² are each independently preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, R ¹³ and R ¹⁴ are preferably a methylene group, ¹⁵ is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

Among these, a unit represented by the formula (3), in which R ^{3 to} R ⁶ are all hydrogen atoms, R ¹³ and R ¹⁴ are methylene groups, and R ¹⁵ is a hydrogen atom, is more preferable. In the case where R ¹⁵ is a hydrogen atom and the organic compound (B1) has a secondary amino group, it is preferable because of high adhesiveness or reactivity with the active material surface.
The organic compound (B1) only needs to contain either the unit of formula (2) or the unit of formula (3), and may contain both of the units of formula (2) and formula (3).

Furthermore, the organic compound (B1) may contain units other than the units of the formulas (2) and (3), and is derived from, for example, maleic acid, acrylamide, sulfur dioxide, vinyl sulfonic acid, or styrene. Units.
The organic compound (B1) may be a low molecular compound or a high molecular compound as long as it has a basic group. From the viewpoint of effectively suppressing gas generation, the high molecular compound is used. The polymer (b1) is preferred.
When the organic compound (B1) is a low molecular compound, a compound composed of vinylamine, allylamine or a derivative thereof is preferable.

  Examples of vinylamine, allylamine and derivatives thereof include vinylamine, N-alkyl-substituted vinylamine (N-methylvinylamine etc.), N, N-dialkyl-substituted vinylamine (N, N-dimethylvinylamine etc.), divinylamine, N -Alkyl-substituted divinylamine (N-methyldivinylamine etc.), allylamine, N-alkyl-substituted allylamine (N-methylallylamine etc.), N, N-dialkyl-substituted allylamine (N, N-dimethylallylamine etc.), diallylamine, N- Examples thereof include alkyl-substituted diallylamine (N-methyldiallylamine and the like), dimers or trimers thereof.

The organic compound (B1) may be in the form of a salt such as acetate, hydrochloride, sulfate, amide sulfate, or ammonium salt. Further, the amine moiety may be modified such as partially ureated.
As an embodiment when the organic compound (B1) is the polymer (b1), the weight average molecular weight can be used as an index.

The weight average molecular weight of the polymer (b1) is not particularly limited, but is preferably 500 or more, more preferably 1000 or more, still more preferably 2000 or more, and particularly preferably 2500 or more. On the other hand, the weight average molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 300,000 or less, and particularly preferably 200,000 or less.
The polymer (b1) is preferably at least one of an amine homopolymer and a copolymer containing an ethylenically unsaturated group. Specifically, it is preferably at least one of homopolymers and copolymers of vinylamine, allylamine or derivatives thereof.

  As the polymer (b1), a homopolymer of any of the above vinylamines, allylamines or derivatives thereof, a copolymer of any two or more of the above vinylamines, allylamines or derivatives thereof, or the above vinylamines, allylamines or derivatives thereof Any one or more of these and one or more copolymers of other components can be used.

Furthermore, maleic acid, acrylamide, sulfur dioxide, etc. may be used as other components. Examples of the copolymer containing other components include diallylamine-maleic acid copolymer.
The polymer (b1) is preferably vinylamine, allylamine, N-alkyl-substituted allylamine (N-methylallylamine, etc.), N, N-dialkyl-substituted allylamine (N, N-dimethylallylamine, etc.) from the viewpoint of initial charge / discharge efficiency. Or diallylamine homolimer or copolymer, more preferably polyvinylamine, polyallylamine, poly-N-methylallylamine, poly-N, N-dimethylallylamine, polydiallylamine, poly-N-methyldiallylamine, most preferably Polyvinylamine or polyallylamine.

(2. Lithium ion coordination group)
A group having a preferable lithium ion coordinating property in the present invention (hereinafter sometimes simply referred to as “lithium ion coordinating group”) is defined as a group having a non-conjugated electron pair, Although not particularly limited to the following description, selected from the group consisting of oxyalkylene group, sulfonyl group, sulfo group, boron-containing functional group, carbonyl group, carbonate group, phosphorus-containing functional group, amide group, and ester group It is preferable that it is at least one kind.

Of these, more preferred examples of the oxyalkylene group include an oxymethylene group, an oxyethylene group, and an oxypropylene group.
These lithium ion coordinating groups can be expected to promote desolvation from the solvent with respect to lithium ions solvated with the electrolyte. Thereby, reductive decomposition of the electrolytic solution is suppressed, and the initial charge / discharge efficiency can be improved. In addition, the lithium ion coordinating group promotes the diffusion of lithium ions in the coating film of the active material (A) on which the coating film is formed. Therefore, it is possible to reduce the negative electrode resistance and obtain a favorable low-temperature input / output. is there.

Hereinafter, the organic compound (B2) having a lithium ion coordination group will be described.
The organic compound (B2) may be a low molecular compound or a high molecular compound as long as it has a lithium ion coordinating group, but from the viewpoint of effectively suppressing gas generation, The polymer (b2) which is a polymer compound is preferable.
The organic compound (B2) can be used singly or in combination of two or more as long as it is an organic compound having a lithium ion coordination group.

  The content of the organic compound (B2) with respect to the organic compound (B1) in the non-aqueous secondary battery negative electrode active material of the present invention is such that a sufficient amount of the organic compound (B1) acts on the active material (A), and From the point which can suppress negative electrode resistance increase, Preferably they are 1 mass% or more and 300 mass% or less, More preferably, they are 2 mass% or more and 150 mass% or less, More preferably, they are 3 mass% or more and 100 mass% or less. Yes, particularly preferably 4% by mass or more and 50% by mass or less, and most preferably 5% by mass or more and 40% by mass or less.

  When the organic compound (B2) is a low molecular weight compound, ethylene glycol, diethylene glycol, triethylene glycol, succinic acid, succinic anhydride, sultone, taurine, monosaccharide, oligosaccharide, cyclodextrin, crown ether, benzenesulfonic acid and their Salts, naphthalenesulfonic acid and salts thereof, acetic acid and salts thereof, benzoic acid and salts thereof, amino acids and salts thereof, boric acid and salts thereof, lactic acid and salts thereof, dibutyl carbonate and the like. Among them, succinic acid, succinic anhydride, sultone, taurine, monosaccharide, oligosaccharide, cyclodextrin, benzenesulfonic acid and salts thereof, naphthalenesulfonic acid and salts thereof, acetic acid and Their salts, benzoic acid and their salts, amino acids and their salts, boric acid and their salts, dibutyl carbonate are preferred.

  The polymer (b2), which is a preferred embodiment when the organic compound (B2) in the present invention is a polymer compound, is represented by the following formula (1).

(In the formula, R ¹ and R ² are each independently a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, a glycidyl group or an epoxy group. AO is an oxyalkylene group having 2 to 5 carbon atoms. And n is an integer from 1 to 50.)
In addition, a glycidyl group is a functional group represented by following formula (4), and an epoxy group is a functional group represented by following formula (5).

The alkyl group in the above formula (1) may be linear or branched, and examples thereof include an alkyl group having 1 to 20 carbon atoms, from the viewpoint of suppressing increase in negative electrode resistance. Preferably, it is a C1-C15 alkyl group, Most preferably, it is a C1-C10 alkyl group.
Examples of the aryl group in the above formula (1) include an unsubstituted or alkyl group-substituted phenyl group. From the viewpoint of easy availability of the material, the unsubstituted or alkyl group having 1 to 4 carbon atoms is preferable. And is particularly preferably an unsubstituted phenyl group.

Examples of the aralkyl group in the above formula (1) include an unsubstituted or alkyl-substituted benzyl group. From the viewpoint of easy availability of the material, an unsubstituted or alkyl group having 1 to 4 carbon atoms is preferable. And particularly preferably an unsubstituted benzyl group.
R ¹ and R ² in the above formula (1) are preferably a hydrogen atom, an alkyl group, an epoxy group, or a glycidyl group, more preferably an alkyl group, an epoxy group, or a glycidyl group from the viewpoint of initial charge / discharge efficiency. More preferred is a glycidyl group.
AO in the above formula (1) is an oxyalkylene group having 2 to 5 carbon atoms, and is preferably an oxyethylene group or an oxypropylene group from the viewpoint of suppressing an increase in negative electrode resistance.

As a preferable combination of R ¹ and R ² and AO, R ¹ and R ² are each independently a hydrogen atom, an alkyl group, an epoxy group, or a glycidyl group, and AO is an oxyalkylene group having 2 to 5 carbon atoms. Is preferred. More preferably, R ¹ and R ² are each independently an alkyl group, an epoxy group, or a glycidyl group, and AO is an oxyalkylene group having 2 to 5 carbon atoms. More preferably, R ¹ and R ² are each independently an alkyl group, an epoxy group, or a glycidyl group, and AO is an oxyethylene group or an oxypropylene group. Most preferably, R ¹ and R ² are both glycidyl groups, and AO is a combination of oxyethylene groups or oxypropylene groups.

In the above formula (1), n represents the number of oxyalkylene groups, and is preferably an integer of 1 to 25 from the viewpoint of suppressing increase in negative electrode resistance.
Specific examples of the polymer (b2) include polyoxyethylene glycol diglycidyl ether, polyoxypropylene glycol diglycidyl ether, butoxypolyethylene glycol glycidyl ether and the like.

The weight average molecular weight of the polymer (b2) is not particularly limited, but is preferably 50 or more, more preferably 150 or more, still more preferably 300 or more, and particularly preferably 350 or more. On the other hand, the weight average molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 10,000 or less, and particularly preferably 5000 or less.
Further, in the active material of the present invention, the organic compound (B1) + (B2) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and preferably based on the active material (A). Is contained in a proportion of 10% by mass or less, more preferably 5% by mass or less, still more preferably 1% or less, particularly preferably 0.5% or less, and most preferably 0.4% or less. When it is within the above range, the active material (A) can be effectively coated, and the effects of improving initial efficiency and suppressing generated gas are increased. Moreover, the increase in the interface resistance between the active material (A) and the coating layer can be suppressed, and the deterioration of the low temperature input / output characteristics can be avoided.

(3. π-conjugated structure)
The organic compound (B) of the present invention may further contain an organic compound (B3) having a π-conjugated structure from the viewpoint of effectively suppressing gas generation and suppressing an increase in negative electrode resistance. preferable. This π-conjugated structure selectively covers the surface of the active material (A) by acting with the π-plane structure portion of the active material (A), thereby effectively suppressing the generation of gas and negative electrode resistance. It is considered possible to suppress the rise in
In the present specification, the compound having the π-conjugated structure is an unsaturated cyclic compound having a structure in which atoms having π electrons are arranged in a ring, satisfying the Hückel rule, and the π electrons are not on the ring. It is localized and the ring has a planar structure.

  Examples of such a π-conjugated structure include furan, pyrrole, imidazole, thiophene, phosphole, pyrazole, oxazole, isoxazole, and thiazole, which are monocyclic five-membered rings; benzene, pyridine, pyrazine, which are monocyclic six-membered rings, Pyrimidine, pyridazine, triazine; bicyclic 5-membered ring + 6-membered ring benzofuran, isobenzofuran, indole, isoindole, benzothiophene, benzophosphole, benzimidazole, purine, indazole, benzoxazole, benzoisoxazole, benzothiazole A bicyclic 6-membered ring + a 6-membered naphthalene, quinoline, isoquinoline, quinoxaline, quinazoline, cinnoline; a ring having a skeleton such as polycyclic anthracene, pyrene;

Among these, at least one selected from the group consisting of a benzene ring, a condensed aromatic ring, and an aromatic heterocycle is preferable from the viewpoint of suppressing gas generation when a non-aqueous secondary battery is used. As the condensed aromatic ring, a naphthalene ring is preferable.
Hereinafter, the organic compound (B3) having a π-conjugated structure will be described.
The organic compound (B3) may be a low molecular compound or a high molecular compound as long as it has a π-conjugated structure, but from the viewpoint of effectively suppressing gas generation, the high molecular compound (Hereinafter sometimes referred to as polymer (b3)).

In the active material of the present invention, the organic compound (B3) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and preferably 9.99% by mass with respect to the active material (A). Hereinafter, it is more preferably contained at a ratio of 5% by mass or less. If it is less than 0.01% by mass, it may be difficult to effectively coat the active material (A). On the other hand, if it is 10% by mass or more, the interface resistance between the active material (A) and the coating layer will increase, resulting in a low temperature. Input / output characteristics may deteriorate.

As the organic compound (B3) described above, a commercially available one may be used, or it can be synthesized by a known method. In addition, in this invention, it can be used individually by 1 type or in combination of 2 or more types.
When the organic compound (B3) is a low molecular weight compound, examples of the organic compound (B3) include naphthalene sulfonic acid, lithium naphthalene sulfonate, sodium naphthalene sulfonate, benzene sulfonic acid, sodium benzene sulfonate, anthracene sulfonic acid, and anthracene sulfone. Examples include sodium acid.

When the organic compound (B3) is a polymer (b3) which is a polymer compound, the polymer (b3) has an ionic group and an aromatic ring.
Examples of the monomer from which the structural unit constituting the polymer (b3) is derived include a monomer having an ionic group and an aromatic ring. The polymer (b3) may be a copolymer of a monomer having an ionic group and not having an aromatic ring and a monomer having an aromatic ring and not having an ionic group.

Examples of the monomer having an ionic group and an aromatic ring include styrene sulfonic acid, lithium styrene sulfonate, sodium styrene sulfonate, vinyl benzoate and vinyl benzoate salts.
Examples of the monomer having an ionic group and not having an aromatic ring include vinyl sulfonic acid, lithium vinyl sulfonate, sodium vinyl sulfonate, acrylic acid, sodium acrylate, lithium acrylate, methacrylic acid, and methacrylic acid. Examples include sodium and lithium methacrylate.

Examples of the monomer having an aromatic ring and not having an ionic group include styrene, benzyl acrylate, benzyl methacrylate and the like.
Specific examples of the polymer containing a structural unit derived from such a monomer include a styrene-vinyl sulfonic acid copolymer, a styrene-vinyl sulfonic acid sodium copolymer, a styrene-vinyl sulfonic acid lithium copolymer, and polystyrene. Sulfonic acid, lithium polystyrene sulfonate, sodium polystyrene sulfonate, styrene-styrene sulfonic acid copolymer, styrene-lithium sulfonic acid lithium copolymer, styrene-sodium styrene sulfonate copolymer, polyvinyl benzoic acid, lithium polyvinyl benzoate , Polyvinyl sodium benzoate, styrene-vinyl benzoic acid copolymer, styrene-vinyl benzoic acid lithium copolymer, styrene-vinyl benzoic acid sodium copolymer, and the like.

  Among them, from the viewpoint of effectively suppressing gas generation, polystyrene sulfonic acid, lithium polystyrene sulfonate, sodium polystyrene sulfonate, styrene-styrene sulfonic acid copolymer, styrene-lithium sulfonic acid lithium copolymer, styrene-styrene Sodium sulfonate copolymer, polyvinyl benzoic acid, polyvinyl benzoate lithium, polyvinyl benzoate sodium, styrene-vinyl benzoate copolymer, styrene-vinyl benzoate lithium copolymer and styrene-vinyl benzoate sodium copolymer preferable.

  Further, polystyrene sulfonic acid, lithium polystyrene sulfonate, sodium polystyrene sulfonate, styrene-lithium lithium sulfonate copolymer and styrene-sodium styrene sulfonate copolymer are more preferable, and lithium polystyrene sulfonate, sodium polystyrene sulfonate, styrene. -Particularly preferred are lithium styrene sulfonate copolymers and styrene-sodium styrene sulfonate copolymers.

The weight average molecular weight of the polymer (b3) is not particularly limited, but is preferably 200 or more, more preferably 1000 or more, still more preferably 2000 or more, and particularly preferably 2500 or more. On the other hand, the weight average molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 300,000 or less, and particularly preferably 200,000 or less.

(4. Structure (S))
The organic compound (B) of the present invention has at least one structure (S) selected from the group consisting of a graft structure, a star structure, and a three-dimensional network structure. It is preferable that this structure (S) is formed when the compound containing the organic compound (B1) and the organic compound (B2) takes a crosslinked structure. Examples of the cross-linking method include chemical cross-linking, physical cross-linking, and ion complex cross-linking. BR> 驍, and chemical cross-linking is more preferable from the viewpoint of high stability.

In this specification, the graft structure refers to a molecule having a structure having one or several types of blocks in which side chains in the molecule are bonded to the main chain.
Further, in this specification, the star structure refers to a molecule in which a plurality of linear molecular chains emerge from an atom that is one branch point in the molecule.
In this specification, the three-dimensional network structure refers to a molecule that is highly branched in one molecule and has many closed paths (loops). Among these structures (S), a three-dimensional network structure is preferable.
The structure (S) can be confirmed by measuring small-angle X-ray scattering, viscoelasticity measurement, and insoluble matter by a good solvent.

<Carbon material (C)>
The carbon material (C) of the present invention is not particularly limited as long as it contains the carbon material (A) and the organic compound (B) described above and the mesopore surface area ratio (SAa / SAb) is 0.63 or less.
The compound (B) is preferably a mixture and / or reaction product of an organic compound (B1) having at least a basic group and an organic compound (B2) containing a group having a lithium ion coordination property, and further a π-conjugated structure The organic compound (B3) having other and other components may be mixed and / or reacted.
Moreover, in this specification, "it contains a carbon material (A) and an organic compound (B)" means the state in which the carbon material (A) and the organic compound (B) are mixed, on the surface of the carbon material (A). A state in which the organic compound (B) is attached, a state in which the organic compound (B) is attached in the pores of the carbon material (A), and the like, in a state of the carbon material (A) and the organic compound (B). It does not depend on the relationship.

  The state of the carbon material (A) and the organic compound (B) is, for example, a technique such as field emission scanning electron microscope-energy dispersive X-ray (SEM-EDX) analysis, X-ray photoelectron spectroscopy (XPS) analysis, etc. It can confirm by observing the particle | grain cross section of the active material for nonaqueous secondary battery negative electrodes using. These confirmation methods may be performed at the time when the non-aqueous secondary battery negative electrode active material is manufactured, or as a negative electrode or non-aqueous secondary battery including the non-aqueous secondary battery negative electrode active material according to the present invention. You may carry out about the manufactured product.

<Physical properties of carbon material (C)>
-Mesopore volume, mesopore surface area In the carbon material of the present invention, the mesopore volume and the mesopore surface area are measured by the BJH method analysis using the adsorption isotherm measured by the nitrogen adsorption method, And the mesopore surface area. The mesopore surface area by BJH method area analysis was calculated by accumulating the side area assuming that the mesopore was cylindrical.

-Mesopore volume in the range of 35 nm or less The mesopore volume in the range of 35 nm or less is preferably 0.001 mL / g or more, more preferably 0.005 mL / g or more, still more preferably 0.007 mL / g or more, Preferably it is 0.1 mL / g or less, More preferably, it is 0.05 mL / g or less, More preferably, it is 0.02 mL / g or less, Most preferably, it is 0.01 mL / g or less.

  If it is within the above range, the gap that allows the nonaqueous electrolyte to enter can be adjusted appropriately, so that lithium ions can be smoothly inserted and desorbed when rapidly charged and discharged, and the low-temperature input / output characteristics are improved. In addition, the deterioration of cycle characteristics due to precipitation of lithium metal can be further suppressed. Furthermore, excessive decomposition of the electrolytic solution can be suppressed, and a decrease in initial efficiency and an increase in the amount of gas generated can be further suppressed.

-Mesopore surface area (SAa) in the range of 2 nm to 4 nm, mesopore surface area (SAb) in the range of 4 nm to 35 nm, mesopore surface area ratio (SAa / SAb)
Mesopore surface area in the range of 2nm~4nm (SAa) is preferably 0.1 m ² / g or more, more preferably 0.5 m ² / g or more, further preferably 0.7 m ² / g or more, Preferably it is 8 m < ² > / g or less, More preferably, it is 4 m < ² > / g or less, More preferably, it is 2 m < ² > / g or less, Most preferably, it is 1.5 m < ² > / g or less.

The mesopore surface area (SAb) in the range of 4 nm to 35 nm is preferably 0.1 m ² / g or more, more preferably 0.5 m ² / g or more, still more preferably 1 m ² / g or more, particularly preferably 1.3 m. ² / g or more, preferably 8 m ² / g or less, more preferably 4 m ² / g or less, still more preferably 3 m ² / g or less, and particularly preferably 2.5 m ² / g or less.

The mesopore surface area ratio (SAa / SAb) is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.2 or more, and usually 0.63 or less, preferably 0.6 or less. , More preferably 0.5 or less, particularly preferably 0.45 or less.
The mesopore surface area (SAa) in the range of 2 nm to 4 nm correlates with the amount of the active end face from which Li ions can be inserted and desorbed, and it is considered that the decomposition reaction activity of the electrolyte is higher. On the other hand, it is considered that the mesopore surface area (SAb) in the range of 4 nm to 35 nm correlates with the amount of the basal plane having a small contribution to the insertion / desorption of Li ions.

  When the mesopore surface area (SAa) in the range of 2 nm to 4 nm is within the above range, the insertion / desorption site of the Li ion of the carbon material is not reduced so much, so the Li ion can be smoothly inserted into the carbon material. -Since desorption can be performed, there is a tendency that deterioration in low-temperature input / output characteristics can be further suppressed. Moreover, since excessive decomposition | disassembly of electrolyte solution can be suppressed, the fall of initial efficiency and the increase in the amount of gas generation can be suppressed more.

  In addition, when the mesopore surface area (SAb) in the range of 4 nm to 35 nm is within the above range, the graphite crystallite is not so small, and at the same time, the mesopore surface area (SAa) in the range of 2 nm to 4 nm is significantly reduced. Therefore, it is possible to further suppress the capacity reduction and the low temperature input / output characteristics. Furthermore, since excessive decomposition of the electrolytic solution can be suppressed, a decrease in initial efficiency and an increase in the amount of gas generated can be further suppressed.

That the mesopore surface area ratio (SAa / SAb) exceeds 0.63 indicates that the decomposition reaction activity of the electrolytic solution becomes excessively high. There is a tendency to increase the generation amount. Therefore, it is important that it is 0.63 or less.
And when it is in the above preferred range, the insertion / desorption site of the Li ion of the carbon material is not reduced so much, and the smooth insertion / desorption of the Li ion to the carbon material can be performed. There is a tendency that deterioration of input / output characteristics can be further suppressed. Moreover, since excessive decomposition | disassembly of electrolyte solution can be suppressed, the fall of initial efficiency and the increase in the amount of gas generation can be suppressed more.

-Volume-based average particle size (average particle size d50)
The volume-based average particle diameter (also referred to as “average particle diameter d50”) of the carbon material of the present invention is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and particularly preferably 15 μm or more. The average particle diameter d50 is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 35 μm or less, and particularly preferably 31 μm or less. When the average particle diameter d50 is within the above range, there is a tendency to suppress an increase in the irreversible capacity of the nonaqueous secondary battery obtained by using the carbon material, loss of the initial battery capacity, Generation of process inconvenience, deterioration of high current density charge / discharge characteristics, and deterioration of low temperature input / output characteristics can also be suppressed.

  In this specification, the average particle size d50 is obtained by adding 10 mL of a 0.2 mass% aqueous solution of polyoxyethylene sorbitan monolaurate (for example, Tween 20 (registered trademark)) as a surfactant to a carbon material. 0.01 g was suspended, and this was introduced as a measurement sample into a commercially available laser diffraction / scattering particle size distribution measurement device (for example, LA-920 manufactured by HORIBA), and the measurement sample was irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute. After that, the volume is defined as a volume-based median diameter measured by the measuring device.

-Circularity The carbon material of the present invention has a circularity of 0.88 or more, preferably 0.90 or more, more preferably 0.91 or more. The circularity is preferably 1 or less, more preferably 0.98 or less, and still more preferably 0.97 or less. There exists a tendency which can suppress the fall of the high current density charge / discharge characteristic of a non-aqueous secondary battery as circularity is in the said range. 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)
As the circularity value, for example, a flow type particle image analyzer (for example, FPIA manufactured by Sysmex Industrial Co., Ltd.) is used, and about 0.2 g of a sample (carbon material) is added to polyoxyethylene (20) sorbitan as a surfactant. After dispersing in a 0.2% by weight monolaurate aqueous solution (about 50 mL) and irradiating the dispersion with an ultrasonic wave of 28 kHz for 1 minute at an output of 60 W, the detection range is specified as 0.6 to 400 μm, and the particle size is The value measured for particles in the range of 1.5-40 μm is used.

  A method for improving the degree of circularity is not particularly limited, but a spheroidized sphere is preferable because the shape of the interparticle voids when the negative electrode is formed is preferable. Examples of spheroidizing treatment include a method of mechanically approaching a sphere by applying a shearing force and a compressive force, and a mechanical / physical treatment in which a plurality of carbon material fine particles are granulated by the adhesive force of the binder or the particles themselves Methods and the like.

-Tap density The tap density of the carbon material of the present invention is preferably 0.7 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, still more preferably 0.85 g / cm ³ or more, particularly preferably 0.9 g. / Cm ³ or more, most preferably 0.95 g / cm ³ or more, preferably 1.3 g / cm ³ or less, more preferably 1.2 g / cm ³ or less, still more preferably 1.1 g / cm ^3. It is as follows.

When the tap density is within the above range, the processability such as streaking during the production of the electrode plate is good, and the high-speed charge / discharge characteristics are excellent. In addition, since the carbon density in the particles is difficult to increase, the rolling property is good and the high-density negative electrode sheet tends to be easily formed.
The tap density was filled into the cell by dropping the carbon material of the present invention through a sieve having a mesh size of 300 μm into a cylindrical tap cell having a diameter of 1.6 cm and a volume capacity of 20 cm ³ using a powder density measuring device. After that, a tap having a stroke length of 10 mm is performed 1000 times and defined as the density obtained from the volume at that time and the mass of the sample.

-X-ray parameter The d value (interlayer distance) of the lattice plane (002 plane) obtained by X-ray diffraction according to the Gakushin method of the carbon material of the present invention is preferably 0.335 nm or more and less than 0.340 nm. More preferably, it is 0.339 nm or less, More preferably, it is 0.337 nm or less. When the d002 value is within the above range, the initial irreversible capacity tends to suppress an increase because the crystallinity of graphite is high. Here, 0.335 nm is a theoretical value of graphite.
The crystallite size (Lc) of the carbon material determined by X-ray diffraction by the Gakushin method is preferably 1.5 nm or more, more preferably 3.0 nm or more. Within this range, the particles are not too low in crystallinity, and a reduction in reversible capacity can be suppressed when a non-aqueous secondary battery is formed. The lower limit of Lc is the theoretical value of graphite.

-Ash content The ash content contained in the carbon material of the present invention 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 of the carbon material. It is. Moreover, it is preferable that the minimum of ash content is 1 ppm or more.
When the ash content is within the above range, when a non-aqueous secondary battery is used, deterioration of battery performance due to the reaction between the carbon material and the electrolyte during charge / discharge can be suppressed to a negligible level. 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.

・ BET specific surface area (SA)
Measured specific surface area by the BET method of the carbon material of the present invention (SA) is preferably ^{1 m} 2 / g or more, more preferably ^2m 2 / g or more, more preferably ^3m 2 / g or more, particularly preferably ^4m 2 / g or more. Moreover, it is preferably 11 m ² / g or less, more preferably 9 m ² / g or less, further preferably 8 m ² / g or less, particularly preferably 7 m ² / g or less, and most preferably 6.5 m ² / g or less.

When the specific surface area is within the above range, it is possible to sufficiently secure the portion where Li enters and exits, so the high speed charge / discharge characteristics output characteristics are excellent, and the activity of the active material against the electrolytic solution can be moderately suppressed. However, the high-capacity battery tends to be manufactured.
In addition, when a negative electrode is formed using a carbon material, an increase in reactivity with the electrolytic solution can be suppressed and gas generation can be suppressed, so that a preferable nonaqueous secondary battery can be provided.

  The BET specific surface area was measured using a surface area meter (for example, a specific surface area measuring device “Gemini 2360” manufactured by Shimadzu Corp.), preliminarily dried at 100 ° C. for 3 hours in a nitrogen stream on a carbon material sample, and then liquid nitrogen. It is defined as a value measured by a nitrogen adsorption BET 6-point method using a gas flow method using a nitrogen-helium mixed gas that is cooled to a temperature and adjusted accurately so that the relative pressure value of nitrogen with respect to atmospheric pressure is 0.3.

-Pore volume in the range of 10 nm to 1000 nm In the carbon material of the present invention, the pore volume in the range of 10 nm to 1000 nm is a value measured using a mercury intrusion method (mercury porosimetry), preferably 0.01 mL. / G or more, more preferably 0.03 mL / g or more, still more preferably 0.05 mL / g or more, preferably 0.3 mL / g or less, more preferably 0.25 mL / g or less, Preferably it is 0.2 mL / g or less.

  If the pore volume in the range of 10 nm to 1000 nm is less than the above range, voids into which the non-aqueous electrolyte can enter are less likely to be reduced. There is a possibility of further avoiding the tendency of the lithium metal to be deposited and the cycle characteristics to be deteriorated due to the lack of time. On the other hand, if it exceeds the above range, the binder is less likely to be absorbed in the gap during electrode plate production, and accordingly, the tendency of the electrode plate strength and initial efficiency to decrease can be further avoided.

The total pore volume of the carbon material of the present invention is preferably 0.1 mL / g or more, more preferably 0.2 mL / g or more, still more preferably 0.25 mL / g or more, and particularly preferably 0.5 mL / g. g or more. The total pore volume is preferably 10 mL / g or less, more preferably 5 mL / g or less, still more preferably 2 mL / g or less, and particularly preferably 1 mL / g or less.
When the total pore volume is within the above range, it is not necessary to make the amount of the binder excessive when forming the electrode plate, and it is easy to obtain the effect of dispersing the thickener or the binder when forming the electrode plate.

The average pore diameter of the carbon material of the present invention is preferably 0.03 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more, and particularly preferably 0.5 μm or more. The average pore diameter is preferably 80 μm or less, more preferably 50 μm or less, and still more preferably 20 μm or less.
When the average pore diameter is within the above range, it is not necessary to make the amount of the binder excessive when forming the electrode plate, and it tends to avoid deterioration of the high current density charge / discharge characteristics of the battery.

As the mercury porosimetry apparatus, a mercury porosimeter (Autopore 9520: manufactured by Micromeritex Corporation) can be used. A sample (carbon material) is weighed to a value of about 0.2 g, enclosed in a powder cell, and pretreated by degassing at room temperature and under vacuum (50 μmHg or less) for 10 minutes.
Subsequently, the pressure is reduced to 4 psia (about 28 kPa), mercury is introduced into the cell, the pressure is increased stepwise from 4 psia (about 28 kPa) to 40000 psia (about 280 MPa), and then the pressure is reduced to 25 psia (about 170 kPa).

The number of steps at the time of pressure increase is 80 points or more, and the mercury intrusion amount is measured after an equilibration time of 10 seconds in each step. The pore distribution is calculated from the mercury intrusion curve thus obtained using the Washburn equation.
Note that the surface tension (γ) of mercury is calculated as 485 dyne / cm and the contact angle (ψ) is 140 °. The average pore diameter is defined as the pore diameter when the cumulative pore volume is 50%.

True density The true density of the carbon material of the present invention is preferably 1.9 g / cm ³ or more, more preferably 2 g / cm 2.
cm ³ or more, more preferably 2.1 g / cm ³ or more, particularly preferably 2.2 g / cm ³ or more, the upper limit is 2.26 g / cm ^3. The upper limit is the theoretical value of graphite. Within this range, the crystallinity of carbon is not too low, and an increase in the initial irreversible capacity in the case of a non-aqueous secondary battery can be suppressed.

Aspect ratio The aspect ratio of the carbon material of the present invention in a powder state is theoretically 1 or more, preferably 1.1 or more, more preferably 1.2 or more. The aspect ratio is preferably 10 or less, more preferably 8 or less, still more preferably 5 or less, and particularly preferably 3 or less.
When the aspect ratio is within the above range, streaking of the slurry containing the carbon material (negative electrode forming material) hardly occurs at the time of forming the electrode plate, and a uniform coated surface is obtained, and high current density charge / discharge of the non-aqueous secondary battery is obtained. There is a tendency to avoid deterioration of characteristics.

  The aspect ratio is expressed as A / B when the longest diameter A of the carbon material particles when observed three-dimensionally and the shortest diameter B among the diameters orthogonal to the carbon material particles. The carbon material particles are observed with a scanning electron microscope capable of magnifying observation. Arbitrary 50 carbon material particles fixed to the end face of a metal having a thickness of 50 microns or less are selected, and the stage on which the sample is fixed is rotated and tilted to measure A and B, and A / B Find the average value of.

・ Maximum particle size dmax
The maximum particle diameter dmax of the carbon material of the present invention is preferably 200 μm or less, more preferably 150 μm or less, still more preferably 120 μm or less, particularly preferably 100 μm or less, and most preferably 80 μm or less. When dmax is within the above range, the occurrence of process inconveniences such as line drawing tends to be suppressed.
The maximum particle size is defined as the value of the largest particle size at which particles are measured in the particle size distribution obtained when measuring the average particle size d50.

-Raman R value The value of the Raman R value of the carbon material of the present invention is preferably 0.1 or more, more preferably 0.15 or more, and still more preferably 0.2 or more. The Raman R value is preferably 0.6 or less, more preferably 0.5 or less, and still more preferably 0.4 or less.
Incidentally, 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, the intensity Defined as the ratio (I _B / I _A ).
Incidentally, the scope of 1580～1620Cm ^-1 A "1580cm around ^-1" in the present specification, "1360cm around ^-1" refers to the range of 1350 ^-1.

When the Raman R value is within the above range, the crystallinity of the carbon material particle surface is unlikely to be high, and when the density is increased, the crystal is difficult to be oriented in a direction parallel to the negative electrode plate, and a tendency to avoid deterioration of load characteristics is avoided. It is in. Furthermore, the crystal on the particle surface is not easily disturbed, and the increase in reactivity with the electrolyte solution of the negative electrode is suppressed, and the decrease in charge / discharge efficiency of the nonaqueous secondary battery and the increase in gas generation 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)

DBP oil absorption The amount of DBP (dibutyl phthalate) oil absorption of the carbon material of the present invention is preferably 65 ml / 100 g or less, more preferably 62 ml / 100 g or less, still more preferably 60 ml / 100 g or less, particularly preferably 57 ml / 100 g or less. It is. The DBP oil absorption is preferably 30 ml / 100 g or more, more preferably 40 ml / 100 g or more.

If the DBP oil absorption amount is within the above range, it means that the progress of spheroidization of the carbon material is sufficient, and there is a tendency that streaking is difficult to occur during the application of the slurry containing the carbon material. However, since the pore structure exists, the reaction surface tends to be prevented from lowering.
The DBP oil absorption amount is defined as a measured value when 40 g of a measurement material (carbon material) is added, a dropping speed is 4 ml / min, a rotation speed is 125 rpm, and a set torque is 500 N · m, in accordance with JIS K6217. For the measurement, for example, Absorbometer E type manufactured by Brabender can be used.

・ Average particle diameter d10
The particle size (d10) corresponding to 10% cumulative from the small particle side of the particle size measured on a volume basis of the carbon material of the present invention is preferably 30 μm or less, more preferably 20 μm or less, still more preferably 17 μm or less, preferably It is 1 μm or more, more preferably 5 μm or more, further preferably 10 μm or more, particularly preferably 11 μm or more, and most preferably 13 μm or more.

When d10 is within the above range, the tendency of the particles to agglomerate does not become too strong, and it is possible to avoid the occurrence of process inconveniences such as an increase in slurry viscosity, a decrease in electrode strength and a decrease in initial charge / discharge efficiency in nonaqueous secondary batteries. In addition, the high current density charge / discharge characteristics and the low temperature input / output characteristics tend to be avoided.
d10 is defined as a value obtained by integrating 10% from a particle size having a small particle frequency% in the particle size distribution obtained when measuring the average particle size d50.

・ Average particle size d90
The particle size (d90) corresponding to 90% of the particle size measured on the volume basis of the carbon material of the present invention is preferably 100 μm or less, more preferably 70 μm or less, still more preferably 60 μm or less, and even more. The thickness is preferably 50 μm or less, particularly preferably 45 μm or less, most preferably 42 μm or less, preferably 20 μm or more, more preferably 26 μm or more, still more preferably 30 μm or more, and particularly preferably 34 μm or more.

When d90 is within the above range, it is possible to avoid a decrease in electrode strength and a decrease in initial charge / discharge efficiency in a non-aqueous secondary battery, generation of process inconveniences such as striation during application of slurry, and high current density charge / discharge characteristics. There is a tendency to avoid the decrease in the temperature and the low-temperature input / output characteristics.
d90 is defined as a value in which the frequency% of particles is 90% integrated from a small particle size in the particle size distribution obtained when measuring the average particle size d50.

-Elution of organic compound (B) The elution of organic compound (B) in the non-aqueous secondary battery negative electrode active material of the present invention is a carbon material at room temperature (25 ° C) in a non-aqueous solvent containing no salt. Can be evaluated by measuring the elution amount of the organic compound (B) into the solution.
The amount of elution can be preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less of the total amount of the organic compound (B) contained in the non-aqueous secondary battery negative electrode active material. It is at most 5% by mass, particularly preferably at most 5% by mass.

When it is within the above range, the organic compound (B) is hardly peeled off during high-temperature storage or charge / discharge cycles, and deterioration of storage characteristics and charge / discharge cycle characteristics can be effectively suppressed.
The non-aqueous solvent used in the elution evaluation can be appropriately selected from known non-aqueous solvents as the solvent for the non-aqueous electrolyte solution. 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.

A non-aqueous solvent may be individual or may use 2 or more types together. In the case of a mixed solvent, a combination of a mixed solvent containing a cyclic carbonate and a chain carbonate is preferable, and among them, the cyclic carbonate is more preferably ethylene carbonate.
As a method for quantifying the elution amount of the organic compound (B), after immersing the non-aqueous secondary battery negative electrode active material in the non-aqueous solvent component, the supernatant is recovered and dried to drive off the solvent, and the NMR or GPC 100 The method of calculating by the ratio of the peak intensity of the eluted component to the peak intensity in the case of% elution is mentioned.

<Method for producing carbon material (C)>
The active material for a nonaqueous secondary battery negative electrode according to the present invention can be produced, for example, by the following method.
The organic compound (B1) and the organic compound (B2) are added to an organic solvent, water, or a mixed solvent thereof in 1) the mixing step, and the solution (D) is mixed with the carbon material (A). ) A non-aqueous secondary battery negative electrode active material in which the carbon material (A) contains the organic compound (B) can be obtained by drying by heating or / and reducing pressure in the drying step.

For example, the solution of the organic compound (B1) and the solution of the organic compound (B2) may be prepared separately, or the organic compound (B1) and the organic compound (B2) are added to the same solvent to obtain a solution. May be prepared. From the viewpoint of the initial charge / discharge efficiency of the lithium ion secondary battery, it is preferable to separately prepare a solution of the organic compound (B1) and a solution of the organic compound (B2).
The solvent to be used is not particularly limited as long as the organic compound (B1) and the organic compound (B2) are dissolved or dispersed, but preferably water, ethyl methyl ketone, toluene, acetone, methyl isobutyl ketone, ethanol, methanol, and the like. Is mentioned. Among these, water, ethyl methyl ketone, acetone, methyl isobutyl ketone, ethanol, and methanol are more preferable because of cost and ease of drying.

Step (1): Mixing Step The method for mixing the carbon material (A) and the organic compound (B) is not particularly limited, but the carbon material (A) is used from the viewpoint of suppressing the initial gas amount and the storage gas amount. It is desirable that the organic compound (B) can be uniformly coated on the surface.
As a mixing method, there are a method of stirring using a stirring blade in a fixed container, a method of rotating and mixing powder by rotating the container itself, and a method of mixing by fluidizing with an air flow. Can be mentioned. Among these, a method of stirring using a stirring blade in a fixed container from the viewpoint of mixing uniformity is preferable. The fixed container at that time is an inverted conical type, a vertical cylinder type, a horizontal cylinder type, a U type. Although a trough is mentioned, it is preferably a horizontal cylinder type from the viewpoint of in-machine adhesion and uniform mixing.

If the shape of the stirring blade is a horizontal axis method, it is a ribbon type, a screw type, a single-axis paddle type, a double-axis paddle type, a squid type, a saddle type, and if it is a vertical axis type, a ribbon type, a screw type, There are a planetary type, a conical screw type, and a lower high-speed rotating blade, but from the viewpoint of uniform mixing, a horizontal axis type saddle type is preferable.
For example, it is preferable to use a mixer having a horizontal axis type vertical stirring blade in a horizontally placed cylindrical container.

The peripheral speed of the stirring blade is preferably 0.1 m / s or more, more preferably 1 m / s or more, still more preferably 2 m / s or more, particularly preferably 3 m / s or more from the viewpoint of mixing uniformity. Yes, preferably 100 m / s or less, more preferably 80 m / s or less, and even more preferably 50 m / s or less.
The treatment time is preferably 0.5 min or more, more preferably 1 min or more, further preferably 5 min or more, preferably 5 hr or less, more preferably 1 hr or less, still more preferably 2
0 min or less. When the processing time is within the above range, it is possible to mix more uniformly while maintaining the processing capability.

The mixing temperature is preferably 1 ° C or higher, more preferably 10 ° C or higher, preferably 100 ° C or lower, more preferably 60 ° C or lower. When the mixing temperature is within the above range, an increase in the viscosity of the organic compound (B) can be suppressed, and more uniform mixing can be achieved. Moreover, the cost for temperature control can also be suppressed.
When the solution of the organic compound (B1) and the solution of the organic compound (B2) are separately prepared, these solutions and the carbon material (A) may be mixed at the same time. After these solutions are mixed, the carbon material ( A) may be mixed, or the carbon material (A) may be mixed with either the organic compound (B1) solution or the organic compound (B2) solution, and then the other solution may be added.

  In order to improve the uniform mixing property, when the state after mixing the solution of the organic compound (B1) and the solution of the organic compound (B2) is a high-viscosity state, solid, or gel, the carbon material ( When mixing A), it is preferable to dilute the organic compound (B) in advance with a solvent from the viewpoint of uniform mixing. More preferably, after diluting organic compound (B2) with a solvent, it is mixed with organic compound (B1) and then mixed with carbon material (A). The time from mixing the solution of the organic compound (B1) and the solution of the organic compound (B2) to mixing with the carbon material (A) is preferably within 1 hr, but preferably within 20 min from the viewpoint of tact time. is there.

The ratio of the solution obtained by diluting the organic compound (B) to the carbon material (A) is preferably 1% by mass or more, more preferably 5% by mass or more, preferably 100% by mass or less, more preferably 30% by mass or less. Good to do. By setting it within the above range, the ratio can be uniformly mixed, and the drying time in the subsequent process can be shortened.
Further, it is preferable to add a solution of the organic compound (B1) and a solution of the organic compound (B2) when preparing the slurry in which the carbon material (A) is dispersed. This can also be achieved by improving the initial charge / discharge efficiency and suppressing gas generation by drying the organic compound (B1) and the organic compound (B2) solvent after applying the negative electrode active material for the negative electrode to the negative electrode plate. This is because the manufacturing process can be simplified.

The slurry in which the carbon material (A) is dispersed is a step of applying the non-aqueous secondary battery negative electrode active material according to the present invention to the negative electrode surface in order to produce a negative electrode for a non-aqueous secondary battery. It is one of the modes used in the above.
Above all, from the viewpoint of initial charge / discharge efficiency, a solution of the organic compound (B1) and a solution of the organic compound (B2) are separately prepared, and these solutions and the carbon material (A) are mixed simultaneously to disperse the active material (A). It is preferable to prepare a slurry. In addition, from the point that the surface of the carbon material (A) can be uniformly coated, after the solution of the organic compound (B1), the solution of the organic compound (B2), and the carbon material (A) are mixed at the same time, More preferably, the organic compound (B3) is mixed after drying.

The concentration of the organic compound (B1) or the organic compound (B2) in the solvent when mixed with the carbon material (A) is preferably 0.01% by mass or more and 70% by mass or less, respectively. Within this range, it can be expected that the organic compound (B1) and the organic compound (B2) are uniformly present on the surface of the carbon material (A) in the non-aqueous secondary battery negative electrode active material, which is effective. Is obtained.
The concentration of the organic compound (B1) or organic compound (B2) in the solution is preferably 0.03% by mass or more, more preferably 0.05% by mass or more, and preferably 60% by mass. Or less, more preferably 40% by mass or less.

However, the above solution concentration is the concentration of the solution when contacting the carbon material (A), and the organic compound (B1) solution and the organic compound (B2) solution are mixed simultaneously with the carbon material (A). In the case of mixing the carbon material (A) after mixing these solutions, the concentration is about the organic compound (B) which is the sum of the organic compound (B1) and the organic compound (B2). When the other solution is added after mixing the carbon material (A) with either the organic compound (B1) solution or the organic compound (B2) solution, the organic compound (B1) solution, the organic compound (B2) solution, The concentration of each of the solutions.
Moreover, the addition amount of the organic compound (B1) and the organic compound (B2) can be appropriately adjusted, and the blending amount is set so as to be a preferable content in the above-described active material for a non-aqueous secondary battery negative electrode of the present invention. It is preferable to adjust.

Step (2): Drying Step When the organic compound (B1) and / or the organic compound (B2) solution is dried by heating, the temperature is not higher than the decomposition temperature of the organic compound (B1) and the organic compound (B2). It is more preferable that the temperature be equal to or higher than the boiling point of the solvent. Preferably they are 50 degreeC or more and 300 degrees C or less. If it is this range, drying efficiency is sufficient, the fall of the battery performance by solvent remaining is avoided, decomposition | disassembly prevention of an organic compound (B1) and an organic compound (B2), carbon material (A), and an organic compound It is possible to easily prevent the effect from being reduced due to weak interaction with (B1) and the organic compound (B2).

The temperature is preferably 250 ° C. or lower, and preferably 100 ° C. or higher.
When drying the solution of the organic compound (B1) and / or organic compound (B2) under reduced pressure, the pressure is usually 0 MPa or less and −0.2 MPa or more in gauge pressure notation (difference from atmospheric pressure). If it is this range, it can dry comparatively efficiently. The pressure is preferably −0.03 MPa or less, and preferably −0.15 MPa or more.

In the drying step, there is no particular limitation as a method for drying the mixture of the carbon material (A) and the organic compound (B), but it is desirable that the coating can be uniformly performed from the viewpoint of suppressing the initial gas amount and the storage gas amount. . By making it uniform, the organic compound (B) can be efficiently adsorbed on the surface of a specific mesopore, and an effect of suppressing gas generation is easily obtained.
Examples of the heat transfer method include a convection heat transfer method in which hot air is directly applied and drying, and a conduction heat transfer method in which heat is transferred from a heat medium through a conductive heating plate, but a conduction heat transfer method is preferable from the viewpoint of yield.

  The moving form of the object to be dried includes stationary drying in which the object to be dried is allowed to dry, hot air conveyance drying in which the object to be dried is dispersed or sprayed with hot air in the hot air, and agitation drying in which drying is performed while stirring. In that case, it is preferable to carry out stirring drying from a viewpoint of drying particles uniformly. Moreover, even if it implements a drying process with the same installation as a mixing process, and it is a separate installation, it is sufficient if the mixing uniformity and the drying capability are hold | maintained.

  As a method of stirring and drying, a method of drying the mixture while stirring with a stirring blade in a fixed container, a method of drying while rotating the powder by rotating the container itself, From the viewpoint of uniformity and yield, a method of drying the mixture while stirring with a stirring blade in a fixed vessel is preferable. It is preferable to use this method.

The stirring tank at that time includes an inverted conical type, a vertical cylinder type, a horizontal cylinder type, and a U-shaped trough. The horizontal cylinder type is preferable from the viewpoint of yield, workability, and installation space.
If the shape of the stirring blade is a horizontal axis type, it is a ribbon type, screw type, single axis paddle type, double axis paddle type, Ikari type, 鋤 BR> ^, hollow wedge type, and if it is a vertical axis type, a ribbon Examples include a mold, a screw type, a conical screw type, and a lower high-speed rotating blade, and a horizontal axis type single-axis paddle type and a saddle type are preferable.

Although the peripheral speed of the stirring blade varies depending on the stirring / drying method, it is preferably 0.01 m / s or more, more preferably 0.2 m / s or more, still more preferably 1 m / s or more, particularly preferably from the viewpoint of uniformity. It is 2 m / s or more, preferably 40 m / s or less, more preferably 20 m / s or less, and still more preferably 10 m / s or less.
In the case of the conduction heat transfer system, the heat medium includes heat medium oil, steam, and electric heater, but steam is preferred from the viewpoint of cost. In addition, the heat medium is transferred to the object to be dried through the heat transfer surface by flowing it through the stirring tank jacket, stirring blade, or stirring shaft, but from the viewpoint of heat transfer efficiency, the stirring tank jacket, stirring blade, and stirring It is preferable to flow a heating medium on all of the shafts.

  For example, a horizontal cylindrical type stirring tank that can be heated by flowing a heat medium through the stirring tank jacket and has a horizontal axis type vertical stirring blade, and two horizontal shaft type hollow wedge stirring blades that mesh with each other CD dryer that can be heated by flowing a heat medium through both the rotating shaft and the casing with a horizontal jacket (Kurimoto Tsukuko), and a horizontal cylindrical stirring tank to flow the heating medium to the stirring tank jacket and stirring blade With a horizontal axis type single-shaft paddle type stirring blade, a ribo-cone with a vertical axis type ribbon type stirring blade that can be heated by flowing a heat medium through the stirring tank jacket in an inverted conical stirring tank (Okawara) Mixon (Toyo High-Tech), which has a vertical axis type ribbon type stirring blade that can be heated by flowing a heat medium through the stirring tank jacket and the stirring blade in a vertically installed cylindrical stirring tank.

  Prior to drying, a step of filtering a solution containing the carbon material (A), the organic compound (B1) and the organic compound (B2), and a step of washing the resulting residue with water may be included. Thereby, it is possible to remove excess organic compound (B1) and organic compound (B2) not directly attached to the carbon material (A), without reducing effects such as improvement of initial efficiency and suppression of gas generation, This is preferable because the low-temperature input / output characteristics can be improved.

In addition, when the active material for a non-aqueous secondary battery negative electrode of the present invention contains other components such as the organic compound (B3), the organic solvent is the same as the organic compound (B1) and the organic compound (B2). In addition to water or a mixed solvent thereof, a solution is prepared, and the solution is mixed with the carbon material (A) and then dried by heating or / and decompression.
When other components such as the organic compound (B3) are added, a solution of the other components may be prepared separately from the solution of the organic compound (B1) or the organic compound (B2). A solution may be prepared in addition to the same solvent as the solution of B1) or organic compound (B2).

<Content of organic compound (B)>
The non-aqueous secondary battery negative electrode active material of the present invention contains a carbon material (A) and an organic compound (B), and is particularly limited as long as the mesopore surface area ratio (SAa / SAb) is 0.63 or less. However, the content of the organic compound (B) can be 0.01% by mass or more and 10% by mass or less with respect to the carbon material (A). In addition, when the organic compound (B) is a polymer (b) that is a polymer compound, the content of the polymer (b) with respect to the carbon material (A) is the same value as the value of the organic compound (B), including a preferable range. It is.

  The content of the organic compound (B) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and preferably 10% by mass or less, more preferably with respect to the carbon material (A). Is 5% by mass or less, more preferably 3% by mass or less, particularly preferably 1% by mass or less, particularly preferably 0.5% by mass or less, and most preferably 0.4% by mass or less. Within the above range, the active material (A) can be effectively coated, and the effects of improving the initial efficiency and suppressing the generated gas can be further exhibited. In addition, an increase in interface resistance between the active material (A) and the coating layer can be suppressed, and a decrease in low-temperature input / output characteristics can be suppressed.

  When the solution containing the organic compound (B) is dried at the time of production, the content of the organic compound (B) is, in principle, the amount of the organic compound (B) added at the time of production. When the organic compound (B) not attached to the raw material (A) is removed, it should be calculated from the weight loss in the TG-DTA analysis of the obtained carbon material or the amount of the organic compound (B) contained in the filtrate. Can do.

The non-aqueous secondary battery negative electrode active material according to the present invention may contain any organic compound in addition to the organic compound (B). The type of the arbitrary organic compound is not particularly limited, but is preferably a polymer from the viewpoint that the adsorption to the carbon material (A) is stably maintained, and the organic compound (B1) having a basic group Polyanionic organic compounds are particularly preferred in that the action is formed.
Although content of the said arbitrary organic compound is not specifically limited, 0.01 mass% or more and 10 mass% or less are preferable with respect to an active material (A).

<Negative electrode for non-aqueous secondary battery>
The negative electrode for a non-aqueous secondary battery of the present invention (hereinafter also referred to as “electrode sheet” as appropriate) includes a current collector and a negative electrode active material layer formed on the current collector, and the active material layer is at least It contains the carbon material of the present invention. More preferably, it contains a binder.
As the binder, one having an olefinically unsaturated bond in the molecule is used. The type is not particularly limited, and specific examples 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 such an olefinically unsaturated bond in combination with the above 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. In addition, since the negative electrode according to the present invention has high adhesive strength between the active material layer and the current collector, even when the binder content in the active material layer is reduced, the negative electrode is wound to produce a battery. It is speculated that the problem that the active material layer peels from the current collector does not occur.

As the binder having an olefinically unsaturated bond in the molecule, one having a large molecular weight or one having a large proportion of unsaturated bonds is desirable. Specifically, in the case of a binder having a high 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. Is desirable. In the case of a binder having a large ratio of unsaturated bonds, the number of moles of olefinically unsaturated bonds per gram of all binders is preferably 2.5 × 10 ⁻⁷ or more, more preferably 8 × 10 ^{−. It} is desirable that the amount is ⁷ mol or more, preferably 1 × 10 ⁻⁶ mol or less, more preferably 5 × 10 ⁻⁶ mol or less. The binder only needs to satisfy at least one of these regulations regarding molecular weight and regulations regarding the proportion of unsaturated bonds, but it is more preferable to satisfy both regulations simultaneously. When the molecular weight of the binder having an olefinically unsaturated bond is within the above range, mechanical strength and flexibility are excellent.

The binder having an olefinically unsaturated bond has an unsaturation degree of 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 that does not have an olefinically unsaturated bond can also be used in combination with the above-described binder that has an olefinically unsaturated bond as long as the effects of the present invention are not lost. 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.

By using a binder that does not have an olefinically unsaturated bond, the coatability can be improved. However, if the combined amount is too large, the strength of the active material layer is lowered.
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 mass ratio of each is preferably 90/10 or more, more preferably 95/5 or more, preferably 99.9 / 0.1 or less, more preferably 99.5 / 0.5 in terms of the dry mass ratio. The range is as follows. When the ratio of the binder is within the above range, a decrease in capacity and an increase in resistance can be suppressed, and the electrode plate strength is also excellent.

  The negative electrode of the present invention is formed by dispersing the above-described carbon material of the present invention and a binder in a dispersion medium to form a slurry, which is applied to a current collector. As the dispersion medium, an organic solvent such as alcohol or water can be used. 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 having an average particle diameter of 1 μm or less, or an alloy thereof. The addition amount of the conductive agent is preferably about 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, preferably 30 μm or less, more preferably 20 μm or less.
This slurry was applied to a width of 5 cm using a doctor blade so that the negative electrode material was 14.5 ± 0.3 mg / cm ² on a 18 μm-thick copper foil as a current collector, and air-dried at room temperature. Went. Further, after drying at 110 ° C. for 30 minutes, roll pressing was performed using a roller having a diameter of 20 cm to adjust the density of the active material layer to 1.70 ± 0.03 g / cm ³ to obtain an electrode sheet.

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, still more preferably. 75 μm 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. cm ³ or more, particularly preferably 1.7 g / cm ³ or more. Moreover, Preferably it is 1.9 g / cm < ³ > or less. When the density is within the above range, a sufficient battery capacity per unit volume can be secured, and the rate characteristics are hardly lowered.

  When producing the negative electrode for non-aqueous secondary batteries using the carbon material of the present invention described above, the method and selection of other materials are not particularly limited. Moreover, when producing a lithium ion secondary battery using this negative electrode, there is no particular limitation on the selection of members necessary for the battery configuration such as the positive electrode and the electrolytic solution constituting the lithium ion secondary battery. Hereinafter, the details of the negative electrode for lithium ion secondary battery and the lithium ion secondary battery using the carbon material of the present invention will be exemplified, but usable materials, production methods and the like are not limited to the following specific examples. Absent.

<Non-aqueous secondary battery>
The basic configuration of the non-aqueous secondary battery of the present invention, particularly the lithium ion secondary battery, is the same as that of a conventionally known lithium ion secondary battery, and usually includes a positive electrode and a negative electrode capable of inserting and extracting lithium ions, and an electrolyte. Is provided. The negative electrode of the present invention described above is used as the negative electrode.
The positive electrode is obtained by forming a positive electrode active material layer containing a positive electrode active material and a binder 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 titanium sulfide, transition metal sulfides such as NiS 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 these, 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 LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ and some of these transition metals are particularly preferable. Is a lithium transition metal composite oxide in which is substituted with another metal. These positive electrode active materials may be used alone or in combination.

  A known binder can be arbitrarily selected and used as the binder for binding the positive electrode active material. Examples include inorganic compounds such as silicate and water glass, and resins having no unsaturated bond such as Teflon (registered trademark) and polyvinylidene fluoride. Among these, a resin having no unsaturated bond is preferable. If a resin having an unsaturated bond is used as the resin for binding the positive electrode active material, the resin may 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 agent is not particularly limited as long as it can be mixed with an active material in an appropriate amount to impart conductivity, but is 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 a current collector for the positive electrode,
Aluminum, nickel, stainless steel (SUS) or the like is used, but is not limited at all.
As the electrolyte, a non-aqueous electrolyte obtained by dissolving a lithium salt in a non-aqueous solvent, or a gel, rubber, or solid sheet obtained by using an organic polymer compound or the like from the non-aqueous electrolyte is used.

  The non-aqueous solvent used in the non-aqueous electrolyte is not particularly limited, and can be appropriately selected from known non-aqueous solvents that have been conventionally proposed as solvents for non-aqueous electrolytes. 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; and cyclic esters such as γ-butyrolactone and γ-valerolactone.

  Any one of these non-aqueous solvents may be used alone, or two or more thereof may be mixed and used. In the case of a mixed solvent, a combination of a mixed solvent containing a cyclic carbonate and a chain carbonate is preferable, and the cyclic carbonate is a mixed solvent of ethylene carbonate and propylene carbonate. This is particularly preferable from the viewpoint that the impossible characteristics are improved. Among these, propylene carbonate is preferably in a range of 2% by mass to 80% by mass, more preferably in a range of 5% by mass to 70% by mass, and further in a 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 between the graphite phases. 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 in the non-aqueous electrolytic solution is not particularly limited, and can be appropriately selected from known lithium salts that can be used for this purpose. 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 Li trifluorosulfonimide ((CF ₃ SO ₂ ) ₂ NLi) Of these, LiClO ₄ , LiPF ₆ , and LiBF ₄ are preferable.

Lithium salts may be used alone or in combination of two or more. 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 above non-aqueous electrolyte and used in the form of a gel, rubber, or solid sheet, specific examples of the organic polymer compound include polyethylene oxide, polypropylene oxide, and the like. Polyether polymer compounds; Cross-linked polymers of polyether polymer compounds; Vinyl alcohol polymer compounds such as polyvinyl alcohol and polyvinyl butyral; Insolubilized vinyl alcohol polymer compounds; Polyepichlorohydrin; Polyphosphazene; Siloxane; vinyl polymer compounds such as polyvinylpyrrolidone, polyvinylidene carbonate, polyacrylonitrile; poly (ω-methoxyoligooxyethylene methacrylate), poly (ω-methoxyoligooxyethylene methacrylate-co-methyl methacrylate) Rate) and polymer copolymers such as poly (hexafluoropropylene-vinylidene fluoride).

  The non-aqueous electrolyte solution described above may further contain a film forming agent. Specific 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 And acid anhydrides such as maleic acid anhydride and succinic acid anhydride. Furthermore, an overcharge inhibitor such as diphenyl ether or cyclohexylbenzene may be added.

When the above additives are used, the content is usually 10% by mass or less, preferably 8% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less. If the content of the additive is too large, other battery characteristics such as an increase in initial irreversible capacity, low temperature characteristics, and deterioration in rate characteristics may be adversely affected.
Further, as the electrolyte, a polymer solid electrolyte which is a conductor of an alkali metal cation such as lithium ion can be used. Examples of the polymer solid electrolyte include a polymer in which a lithium salt is dissolved in the aforementioned polyether polymer compound, and a polymer 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. As a material for the separator, polyolefin such as polyethylene and polypropylene, polyethersulfone, and the like are used, and polyolefin is preferable.
The form of the nonaqueous secondary battery of the present invention is not particularly limited. Examples include a cylinder type in which a sheet electrode and a separator are spiral, 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. 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, the negative electrode is placed on the outer case, and the electrolytic solution is placed thereon. A separator is provided, and a positive electrode is placed so as to face the negative electrode, and it is caulked together with a gasket and a sealing plate to form a battery.

  EXAMPLES Next, specific embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<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 prepared using the graphite particles of the examples or comparative examples. Specifically, 50.00 ± 0.02 g of negative electrode material, 50.00 ± 0.02 g of 1 mass% carboxymethylcellulose sodium salt aqueous solution (0.500 g in terms of solid content), 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.

Using this slurry, a small die coater made by Itochu Machining was used so that the negative electrode material was 12.00 ± 0.3 mg / cm ² on a 10 μm thick copper foil as a current collector.
The electrode sheet was obtained by adjusting the density of the active material layer to 1.60 ± 0.03 g / cm ³ by roll pressing using a roller having a diameter of 20 cm.

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

<Production method of non-aqueous secondary battery (laminated battery)>
The electrode sheet produced by the above method was cut into 4 cm × 3 cm to form a negative electrode, a positive electrode made of NMC was cut out with the same area, and a separator (made of a porous polyethylene film) was placed between the negative electrode and the positive electrode for combination. 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.

<Measurement method of discharge capacity and initial efficiency>
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 sum of the difference between the charge capacity and the discharge capacity of the total two cycles was calculated as the irreversible capacity. The discharge capacity at the second cycle was defined as the discharge capacity of the material, and the discharge capacity of the material / (discharge capacity of the material + irreversible capacity) was defined as the initial efficiency.

<Initial gas volume, storage gas volume>
The laminate type battery produced by the above-mentioned method is left for 12 hours, and then charged at a current density of 0.2 CmA / cm ³ until the potential difference between both electrodes becomes 4.1 V, and then until the voltage becomes 3 V Discharge was performed at 2 CmA / cm ³ . This was repeated twice, and further charging was carried out with the same current value until the potential difference between both electrodes reached 4.2V. The amount of swelling a (mL) generated so far was measured by the immersion volume method (solvent replacement method based on Archimedes' principle). Then, it was left to stand in an 85 degreeC thermostat for 24 hours, and the amount b (mL) which swells further was calculated | required. At this time, a (mL) was set as “initial gas amount”, and b (mL) was set as “preserved gas amount”.

<Low temperature output characteristics>
Using the laminate type non-aqueous electrolyte secondary battery produced by the method for producing the non-aqueous electrolyte secondary battery, low temperature output characteristics were measured by the following measuring method.
For non-aqueous electrolyte secondary batteries that have not undergone charge / discharge cycles, a voltage range of 4.1 V to 3.0 V at 25 ° C., a current value of 0.2 C (the rated capacity with a discharge capacity of 1 hour rate is discharged in 1 hour) 3C for the current value to be 1C, the same applies hereinafter), voltage range of 4.2V to 3.0V, current value of 0.2C (at the time of charging 4.2V constant voltage charging for another 2.5 hours) Implementation) Initial charge and discharge was performed for 2 cycles.

  Furthermore, after charging at a current value of 0.2 C to SOC 50%, in a low temperature environment of −30 ° C., each current value of 1/8 C, 1/4 C, 1/2 C, 1.5 C, 2 C is 2 seconds. Measure the drop in battery voltage after 2 seconds of discharge under each condition, and calculate the current value I that can flow for 2 seconds when the upper limit of charge voltage is 3V. The value calculated by the formula 3 × I (W) was used as the low temperature output characteristic of each battery.

<D50>
A carbon material (0.01 g) is suspended in 10 mL of a 0.2 mass% aqueous solution of polyoxyethylene sorbitan monolaurate (for example, Tween 20 (registered trademark)), which is a surfactant, and this is a measurement sample. And introduced into a commercially available laser diffraction / scattering particle size distribution measuring apparatus (for example, LA-920 manufactured by HORIBA), and the measurement sample was irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute, and then the volume-based median diameter was measured in the measuring apparatus. As measured.

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

<Tap density>
The carbon material of the present invention was dropped into a cylindrical tap cell having a diameter of 1.6 cm and a volume capacity of 20 cm ³ using a powder density measuring instrument through a sieve having an opening of 300 μm and filled into the cell, and then the stroke length was 10 mm. Was defined as the density obtained from the volume at that time and the mass of the sample.

<Mesopore volume and mesopore surface area by nitrogen adsorption method>
After performing heat treatment under reduced pressure at 100 ° C. for 3 hours, an adsorption isotherm (adsorption gas: nitrogen) was measured at a liquid nitrogen temperature using Autosorb 3B manufactured by Canterchrome. Using the obtained adsorption isotherm, the mesopore volume and mesopore area at each pore size were determined by BJH method analysis.

As carbon material (A), d50, SA, Tap, SAa / SAb, and mesopore volumes of 35 nm or less are 17.4 μm, 6.5 m ² / g, 1.04 g / cm ³ , 0.91, and 0.01 ml, respectively. / G spheroidized natural graphite 30 kg, polyallylamine (PATO-03 made by Nittobo) as the organic compound (B1), and polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol made by NOF Corporation) as the organic compound (B2) 3 kg of an aqueous solution prepared by adjusting and mixing E-400) to a concentration of 1.5% and 0.5%, respectively, was mixed using a mixer having a horizontal cylindrical cylindrical stirring blade. The obtained sample was statically dried by convection heat transfer at 120 ° C. for 7 hours in an air atmosphere and sieved to obtain a powdery carbon material (C) for a non-aqueous secondary battery negative electrode. With the measurement method, d50, SA, Tap, SAa / SAb, mesopore volume of 35 nm or less, initial efficiency, discharge capacity, initial gas amount, storage gas amount, and low-temperature output characteristics were measured. The results are shown in Tables 1 and 2.

As carbon material (A), d50, SA, Tap, SAa / SAb, and mesopore volumes of 35 nm or less are 17.4 μm, 6.5 m ² / g, 1.04 g / cm ³ , 0.91, and 0.01 ml, respectively. / G spheroidized natural graphite 15 kg, polyallylamine (Nittobo PAA-03) as the organic compound (B1), and polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol manufactured by NOF Corporation) as the organic compound (B2) 15 kg of an aqueous solution prepared by adjusting and mixing E-400) to a concentration of 0.15% and 0.05%, respectively, was mixed with a mixer having a horizontal cylindrical cylindrical stirring blade. The obtained sample was filtered and further washed with 10 kg of pure water. Furthermore, it was statically dried by convection heat transfer in an air atmosphere at 120 ° C. for 7 hours, and sieved to obtain a powdery non-aqueous secondary battery negative electrode carbon material (C). From the amount of resin contained in the filtrate, the amount of resin attached to the non-aqueous secondary battery negative electrode carbon material (C) was calculated to be 0.15% and 0.05%, respectively. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

As carbon material (A), d50, SA, Tap, SAa / SAb, and mesopore volumes of 35 nm or less are 17.4 μm, 6.5 m ² / g, 1.04 g / cm ³ , 0.91, and 0.01 ml, respectively. / G spheroidized natural graphite 30 kg, polyallylamine (PATO-03 made by Nittobo) as the organic compound (B1), and polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol made by NOF Corporation) as the organic compound (B2) 3 kg of an aqueous solution prepared by adjusting and mixing E-400) to a concentration of 1.1% and 0.4%, respectively, was mixed using a mixer having a horizontal cylindrical cylindrical stirring blade. Further, 3 kg of an aqueous solution of sodium polystyrenesulfonate (PS-5) manufactured by Tosoh Organic Chemical Co., Ltd., adjusted to a concentration of 2.2% was added as the organic compound (B3) and mixed with a mixer. The obtained sample was statically dried by convection heat transfer at 120 ° C. for 7 hours in an air atmosphere and sieved to obtain a powdery carbon material (C) for a non-aqueous secondary battery negative electrode. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

  1.5% each of polyallylamine (PATO-03 manufactured by Nittobo) as the organic compound (B1) and polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol E-400 manufactured by NOF Corporation) as the organic compound (B2), A carbon material (C) for a nonaqueous secondary battery negative electrode was obtained in the same manner as in Example 3 except that the concentration was adjusted to 0.5% and mixed. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

As carbon material (A), d50, SA, Tap, SAa / SAb, and mesopore volumes of 35 nm or less are 17.4 μm, 6.5 m ² / g, 1.04 g / cm ³ , 0.91, and 0.01 ml, respectively. / G spheroidized natural graphite 30 kg, polyallylamine (PATO-03 made by Nittobo) as the organic compound (B1), and polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol made by NOF Corporation) as the organic compound (B2) 3 kg of an aqueous solution prepared by adjusting and mixing E-400) to a concentration of 1.5% and 0.5%, respectively, was mixed using a mixer having a horizontal cylindrical cylindrical stirring blade. Furthermore, as an organic compound (B3), 3 kg of an aqueous solution of sodium polystyrene sulfonate adjusted to a concentration of 2.2% (manufactured by Tosoh Organic Chemical Co., Ltd. (PS-5)) was added, and a horizontal cylindrical vertical shaft type vertical type was added. It mixed with the mixer which has a stirring blade. It is a horizontal cylindrical stirring tank that can be heated by flowing a heat medium through the stirring tank jacket, and is a mixer with a capacity of 130 L with a horizontal axis type vertical stirring blade, and stirred at a peripheral speed of 4.2 m / s while being 120 ° C. The mixture was dried for 90 minutes in an air atmosphere to obtain a carbon material (C) for a non-aqueous secondary battery negative electrode. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

  Polyallylamine (PAA-03 manufactured by Nittobo) as the organic compound (B1), polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol E-400 manufactured by NOF Corporation) as the organic compound (B2), and organic compound (B3) Example 2 except that 15 kg of an aqueous solution prepared by adjusting and mixing sodium polystyrenesulfonate (PS-5) manufactured by Tosoh Organic Chemical Co., Ltd. to a concentration of 0.15%, 0.05% and 0.5%, respectively, was used. Similarly, a carbon material (C) for a nonaqueous secondary battery negative electrode was obtained. From the amount of resin contained in the filtrate, the amount of resin attached to the non-aqueous secondary battery negative electrode carbon material (C) was calculated to be 0.15%, 0.05%, and 0.22%, respectively. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

  A nonaqueous secondary battery as in Example 4 except that sodium polystyrene sulfonate (manufactured by Tosoh Organic Chemical Co., Ltd. (PS-5)) was used as the organic compound (B3) after adjusting and mixing to a concentration of 5%. A carbon material for negative electrode (C) was obtained. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

[Comparative Example 1]
As carbon material (C) for non-aqueous secondary battery negative electrode, d50, SA, Tap, SAa / SAb, mesopore volume of 35 nm or less are 17.4 μm, 6.5 m ² / g, 1.04 g / cm ³ , respectively. Spherical natural graphite having 0.91 and 0.01 ml / g was used as it was. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

[Comparative Example 2]
As carbon material (A), d50, SA, Tap, SAa / SAb, and mesopore volumes of 35 nm or less are 17.4 μm, 6.5 m ² / g, 1.04 g / cm ³ , 0.91, and 0.01 ml, respectively. 1 kg of spheroidized natural graphite and 200 g of 5% polyallylamide aqueous solution as an organic compound (B) were mixed with a mixer. The obtained sample was statically dried at 120 ° C. for 7 hours in an air atmosphere and sieved to obtain a powdery non-aqueous secondary battery negative electrode carbon material (C). About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

[Comparative Example 3]
A carbon material (C) for a nonaqueous secondary battery negative electrode was obtained in the same manner as in Example 1 except that 200 g of 5% polyacrylic acid aqueous solution was changed to 400 g of 2% carboxymethylcellulose sodium salt aqueous solution. About this, the same measurement as Example 1 was performed. The results are shown in Tables 1 and 2.

As a carbon material (A), d50, SA, Tap, SAa / SAb, and mesopore volumes of 35 nm or less are 10.9 μm, 8.6 m ² / g, 0.94 g / cm ³ , 0.81, and 0.014 ml, respectively. 1 g of spheroidized natural graphite, polyallylamine (Nittobo PAA-03) as the organic compound (B1), and polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol manufactured by NOF Corporation) as the organic compound (B2) 100 g of an aqueous solution prepared by adjusting and mixing E-400) to a concentration of 1.6% and 0.5%, respectively, was mixed with a mixer. Furthermore, as an organic compound (B3), 100 g of an aqueous solution of sodium polystyrene sulfonate (PS-5) manufactured by Tosoh Organic Chemical Co., Ltd. adjusted to a concentration of 2.3% was added and mixed with a mixer. The obtained sample was statically dried at 120 ° C. for 7 hours in an air atmosphere and sieved to obtain a powdery non-aqueous secondary battery negative electrode carbon material (C). About this, the same measurement as Example 1 was performed. The results are shown in Tables 3 and 4.

As a carbon material (A), d50, SA, Tap, SAa / SAb, and mesopore volumes of 35 nm or less are 10.9 μm, 8.6 m ² / g, 0.94 g / cm ³ , 0.81, and 0.014 ml, respectively. 1 g of spheroidized natural graphite, polyallylamine (Nittobo PAA-03) as the organic compound (B1), and polyoxyethylene glycol diglycidyl ether aqueous solution (Epiol manufactured by NOF Corporation) as the organic compound (B2) E-400) and sodium polystyrene sulfonate (manufactured by Tosoh Organic Chemical Co., Ltd. (PS-5)) as the organic compound (B3) were adjusted and mixed to concentrations of 0.15%, 0.05% and 0.5%, respectively. 1 kg of the aqueous solution was mixed with a mixer. The obtained sample was filtered and further washed with 500 g of pure water. Furthermore, it stood and dried by 120 degreeC and the air atmosphere for 7 hours, the sieve process was performed, and the carbon material (C) for powdery non-aqueous secondary battery negative electrodes was obtained. From the amount of resin contained in the filtrate, the amount of resin attached to the non-aqueous secondary battery negative electrode carbon material (C) was calculated to be 0.15%, 0.05%, and 0.23%, respectively. About this, the same measurement as Example 1 was performed. The results are shown in Tables 3 and 4.

[Comparative Example 4]
As carbon material (C) for non-aqueous secondary battery negative electrode, d50, SA, Tap, SAa / SAb, mesopore volumes of 35 nm or less are 10.9 μm, 8.6 m ² / g, 0.94 g / cm ³ , respectively. Spherical natural graphite with 0.81 and 0.014 ml / g was used as it was. About this, the same measurement as Example 1 was performed. The results are shown in Tables 3 and 4.

In Examples 1 to 7, the carbon material (A) is attached with the prescribed organic compound (B), so that S
Since Aa / SAb could be within the specified range, it was possible to effectively suppress side reactions with the electrolyte, and good initial efficiency, initial / preserved gas amount, and low-temperature output characteristics were exhibited. However, in Example 7 , since the pore volume of 35 nm or less was outside the preferred range, the low-temperature output characteristics were deteriorated.

On the other hand, in Comparative Examples 1 and 5 in which the organic compound (B) was not added, the initial reaction decreased and the initial / preserved gas amount increased as the side reaction with the electrolyte proceeded excessively. Further, in Comparative Examples 2 and 3 to which an unspecified organic compound was attached, since SAa / SAb was out of the specified range, a decrease in initial efficiency and an increase in the initial / preserved gas amount were observed.

  The carbon material of the present invention provides a lithium ion secondary battery that is excellent in high capacity, high-temperature storage characteristics, input / output characteristics, and generates a small amount of gas by using it as an active material for a negative electrode of a non-aqueous secondary battery. be able to. Moreover, according to the manufacturing method of the said material, since there are few processes, it can manufacture stably and efficiently and cheaply.

Claims (10)

A carbon material for a non-aqueous secondary battery negative electrode containing a carbon material (A) capable of occluding and releasing lithium ions and an organic compound (B), wherein the mesopore surface area ratio (SAa / SAb
) Is 0.63 or less, the carbon material for non-aqueous secondary batteries (C).
(Formula 1) SAa / SAb = Mesopore surface area of 2 nm to 4 nm determined by nitrogen adsorption method / Mesopore surface area of 4 nm to 35 nm determined by nitrogen adsorption method The carbon material (C) for a non-aqueous secondary battery according to claim 1, wherein a mesopore volume of 35 nm or less determined by a nitrogen adsorption method is 0.007 ml / g or more. The carbon material (C) for a non-aqueous secondary battery according to claim 1 or 2, wherein the carbon material (A) is spheroidized natural graphite. The mesopore volume of 35 nm or less determined by the nitrogen adsorption method of the carbon material (A) is 0.007 m.
The carbon material (C) for a non-aqueous secondary battery according to any one of claims 1 to 3, wherein the carbon material (C) is 1 / g or more. The carbon material for a non-aqueous secondary battery according to any one of claims 1 to 4, wherein the organic compound (B) has a basic group and a group having a lithium ion coordination property. C). The carbon material (C) for a non-aqueous secondary battery according to claim 5, wherein the organic compound (B) has a π-conjugated structure. It is a manufacturing method of the carbon material (C) for nonaqueous system rechargeable batteries given in any 1 paragraph of Claims 1-6 ,
Step (1): Step of mixing carbon material (A) and organic compound (B) in a solvent Step (2): A step of stirring and drying the mixture obtained in Step (1) The manufacturing method of the carbon material (C) for non-aqueous secondary batteries. In the step (2), using a stirring device having a stirring blade in a fixed container, the stirring blade is dried with stirring and mixing by stirring at a peripheral speed of 0.01 m / s to 40 m / s. The manufacturing method of the carbon material (C) for non-aqueous secondary batteries of Claim 7 characterized by the above-mentioned. A carbon material for a non-aqueous secondary battery according to any one of claims 1 to 6, wherein the active material layer includes a current collector and an active material layer formed on the current collector. A negative electrode for a non-aqueous secondary battery, comprising C). A nonaqueous secondary battery comprising a positive electrode and a negative electrode capable of inserting and extracting lithium ions, and an electrolyte, wherein the negative electrode is the negative electrode for a nonaqueous secondary battery according to claim 9 .