JPH1087311A - Fine graphite particles, their production and lithium battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain fine graphite particles for a lithium battery free from mechanical damage on the surface layers and having low surface activity to various org. solvents, high stability and an isotropic shape by carrying out vapor growth in a reaction chamber at a specified temp. or below by Boudouard reaction or reverse reaction of water gas. SOLUTION: Vapor growth is carried out in a reaction chamber 1 at <=700 deg.C by Boudouard reaction represented by the formula 2CO→CO2 +C (deposition) or reverse reaction of water gas represented by the formula H2 +CO→H2 +C (deposition) to obtain the objective fine graphite particles having <=10μm average particle diameter, an isotropic shape, <=30mJ/m<2> heat of immersion in hexane at 25 deg.C, <=30mJ/m<2> heat of immersion in benzene at 25 deg.C and low surface activity. It is preferable that the graphitization reaction is accelerated by disposing a transition metallic material 2 in the reaction chamber 1 or allowing vapor of an alkali metallic carbonate to coexist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to graphite fine particles suitable for use in lithium ion batteries and the like, a method for producing the same, and a lithium battery using the same.

[0002]

2. Description of the Related Art Conventionally, in the production of graphite, it has been necessary to raise the temperature to about 2600 ° C. even if a graphitizable material is used. For example, Lonza's artificial graphite (model name, KS-6) is manufactured in the above temperature range and has a size of about 6 μm in average particle size. According to this, the bottom surface (C-plane) is a flaky particle with a large development, and the columnar surface (edge surface) is not so developed.

Accordingly, a molded body using the flaky particles is easily oriented by the pressure during molding, and the direction in which the pressure is applied is perpendicular to the bottom surface. In addition, considering the case of using for a lithium battery, lithium atoms repeatedly enter and exit from the column surface side, so that the flaky feature where the column surface has not developed is very disadvantageous. That is, although the particles as a whole have the ability to allow lithium to enter and exit, it must be said that the entrance of lithium atoms is extremely narrow because lithium atoms can enter and exit only from the pillar surface. Therefore, there is a problem that not only the number of lithium atoms that can enter and exit per time is restricted, but also that the lithium atoms need to diffuse inside the particles, which causes a time delay.

[0004] In addition, if lithium atoms (dead lithium atoms) which cannot be emitted due to some reason near the entrance of lithium atoms are generated, there is a problem that the discharge capacity is immediately reduced.

[0005] Therefore, in order to avoid such inconveniences, it is necessary to have isotropic particle diameters in which the area ratio between the columnar surface and the bottom surface is substantially equal.

On the other hand, in an industrial method for producing fine graphite by washing and pulverizing natural graphite while removing impurities, it is possible to surely obtain particles having an isotropic particle diameter of about 10 μm or less. However, as clarified by the present inventors from the measurement of the immersion heat of the organic solvent, the surface of the graphite particles by this industrial method is considerably damaged by the grinding, and is far from the ideal graphite structure. Separated. In other words, the surface of the graphite particles is turned into hard carbon (hardly graphitized carbon) (published by the Society of Thermometry in October 1995).

Therefore, when graphite particles obtained by the above-mentioned industrial method are used for a negative electrode of a lithium battery, characteristics exceeding the ideal capacity (372 mAh / g) of graphite may be obtained. Limited and does not last long. That is, since the graphite structure near where lithium atoms can enter and exit is disordered, dead lithium atoms are likely to be generated, and there is no possibility that the disorder of the structure will be restored to its original state even after repeated charge and discharge cycles. There's a problem.

[0008] The surface state of the graphite structure is disordered.
Since it has a very high activity with respect to various organic solvents, it easily causes various interactions with an organic solvent used for an electrolyte for a lithium battery, and causes a problem of compatibility with the electrolyte solvent.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has no mechanical damage to its surface layer, and has a high surface area for various organic solvents used in lithium batteries. The present invention provides graphite particles having low activity and high stability, and further has an isotropic shape with an average particle diameter of about 10 μm or less, and a method for producing the same. And a lithium battery having high resistance to charge / discharge cycles.

[0010]

The invention according to claim 1 is
At 700 ° C. or lower, a reaction represented by the following formula (1) or (2), 2CO → CO ₂ + C (precipitation)... (1) H ₂ + CO → H ₂ O + C (precipitation). Graphite fine particles having an average particle diameter of 10 μm or less and having an isotropic shape.

According to a second aspect of the present invention, in the graphite fine particles according to the first aspect, the immersion heat of hexane and benzene is 30 mJ / m ² or less and the immersion heat of n-butanol and tertiary butanol are each 25 ° C. 60mJ / m
² or less, the immersion heat of dimethyl sulfoxide is 150 mJ /
m ² or less, and the surface immersion heat of the dotriacontan / hexane solution is 80 mJ / m ² or less, and the surface activity is low.

The invention according to claim 3 is characterized in that at 700 ° C. or less,
By the reaction represented by the following formula (1) or (2), 2CO → CO ₂ + C (deposition)... (1) H ₂ + CO → H ₂ O + C (deposition). This is a method for producing fine particles.

According to a fourth aspect of the present invention, in the method for producing fine graphite particles according to the third aspect, a material mainly composed of a transition metal material is used in the reaction chamber or a part of the reaction chamber.

The invention according to claim 5 is the invention according to claim 3 or 4.
In the method for producing graphite fine particles described above, a material having a transition metal material as a main component is arranged in a reaction chamber.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the method for producing graphite fine particles described above, the transition metal material is a porous material.

The invention according to claim 7 is the invention according to claims 3 to 6
In the method for producing graphite fine particles according to any one of the above, steam of an alkali metal carbonate coexists in the reaction chamber.

The invention according to claim 8 is the invention according to claims 3 to 6
The method for producing graphite fine particles according to any of the above, wherein the alkali metal carbonate is stored in a container communicating with the reaction chamber, and the vapor of the alkali metal carbonate generated in the container coexists in the reaction chamber. It is.

The invention according to claim 9 is the invention according to claim 7 or 8.
In the method for producing graphite particles according to the above, the alkali metal carbonate is lithium carbonate, sodium carbonate, potassium carbonate,
It is a simple substance of rubidium carbonate or cesium carbonate or a mixture having an arbitrary mixing ratio.

According to a tenth aspect of the present invention, in the method for producing graphite fine particles according to any one of the third to ninth aspects, prior to vapor phase growth, seeds of the graphite fine particles grown in advance are introduced into a reaction chamber. Things.

An eleventh aspect of the present invention is a lithium battery using the graphite fine particles according to the first or second aspect as a negative electrode.

According to a twelfth aspect of the present invention, there is provided a lithium battery using the graphite fine particles produced by the method for producing graphite fine particles according to any one of the third to tenth aspects as a negative electrode.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have found that graphite fine particles grow in a low temperature range of 700 ° C. or lower, contrary to common sense. It is generally said that soot is formed in this temperature range (New Carbon Industry, Ishikawa, Nagaoki, 198).
0, modern editorial company). Hereinafter, a reaction of depositing carbon at 700 ° C. or lower will be considered.

Reaction for producing water (2H ₂ + O ₂ → 2H
And ₂ O), and the reaction generating _{CO (2C + O 2 → 2CO} ), the free energy of the reaction intersect at around 700 ° C.. At 700 ° C. or lower, CO becomes unstable, and at 700 ° C. or higher, water becomes unstable. Therefore, the water gas reaction (C +
Regarding H ₂ O → CO + H ₂ ), at 700 ° C. or higher, a water gas generation reaction occurs, and at 700 ° C. or lower, a carbon deposition reaction occurs. Therefore, carbon deposition by the reverse reaction of the water gas reaction can occur only in a temperature range of 700 ° C. or less. Of course, there is no thermodynamic necessity that the precipitated carbon is graphite.

On the other hand, it is known that there is a reaction of depositing carbon from the thermal decomposition of carbon monoxide. The so-called Boodouard reaction, ie, 2CO →
C + CO ₂ .

The consideration of this Boudouard reaction is as follows:
It is necessary to consider the stability of CO and CO _2. However, since the stability of CO ₂ is very close to the stability of water, the stability of CO ₂ is It can be discussed by replacing with stability. That is, at 700 ° C. or higher CO is stable, CO ₂ is stable at 700 ° C. or less. Therefore, it can be said that carbon deposition due to this Boudouard reaction can only occur at 700 ° C. or lower.

As a reaction other than the above, a direct reduction reaction of CO _{2 with} H ₂ is not conceivable, but usually, a water-gas shift reaction H ₂ + CO ₂ → H ₂ O + CO occurs first, and CO is produced. Generate. This water-gas shift reaction is not the final reaction for depositing carbon, but it can be said that it is a reaction that cannot be ignored depending on the starting gas composition.

The reduction reaction of CH ₄ with CO (CH
4 + 2CO → 3C + 2H ₂ O) is not inconceivable, but its equilibrium constant is very small and it can be concluded that no carbon is produced.

From the above considerations, the carbon deposition reaction at a temperature of 700 ° C. or less is the reverse reaction of the water gas and the Boudouard.
It can be said that there are two possibilities depending on the reaction. 600 ° C
, The equilibrium constant Kp for both reactions was 3.94, respectively.
(= PH2O / PCOPH2) and 12.4 (= PCO
2 / PCO ² ). Both of these reactions reduce the gas volume during carbon deposition (2 → 1 mol),
The higher the pressure at the start, the better the carbon deposition reaction proceeds, and the higher the carbon yield. Also, the methanation reaction (CO + 3H ₂ → CH ₄ + H ₂ O) may occur as a side reaction depending on the composition of the starting gas. But its speed is not so great.

Although it has been stated earlier that the carbon to be deposited is not necessarily graphite, it is known that the stable range of graphite ranges from a reduced pressure to a pressure of about 1000 atm until around 2000 ° C. (Crystal Growth Handbook, Kyoritsu Shuppan, 1995, p. 340). Therefore, it is considered that the deposited carbon can continue to grow as graphite as long as there is some driving force for graphitization.

The driving force for graphitization confirmed by the inventors is that transition metals such as nickel, iron, cobalt and chromium coexist during the reaction.

The transition metal material coexisting in the reaction chamber or the reaction chamber where graphite grows promotes the water-gas shift reaction. Further, a transition metal material that easily generates a compound carbonyl with CO such as nickel or iron has an effect on promoting the reaction.

In order to further exert the effect of the transition metal material, it is effective to partially use a porous body having a large surface area.

The coexistence of alkali metal carbonate vapor in the reaction chamber can further promote the graphitization reaction.

Further, by providing a vessel communicating with the reaction chamber and storing the alkali metal carbonate in this vessel, the temperature of the vessel is controlled separately, and the vapor pressure of the alkali metal carbonate is increased, whereby the graphite is further increased. Can be promoted.

The alkali metal carbonate is preferably lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate alone or a mixture having an arbitrary mixing ratio.

In addition, since the growth of graphite is continued, if a so-called seed of graphite is put in the reaction chamber in advance in the early stage of growth, the growth will continue on it.
Advantageously and with good reproducibility, graphite fine particles of uniform quality can be produced.

Under the above conditions with the driving force for graphitization, at 700 ° C. or lower, a reaction according to the following formula (1) or (2), 2CO → CO ₂ + C (precipitation) (1) H ₂ + CO → H ₂ O + C (precipitation) (2) The graphite fine particles can be vapor-phase grown to produce graphite fine particles.

As described above, isotropic graphite fine particles having an average particle diameter of 10 μm or less are obtained by the reaction at 700 ° C. or less, and when used as a negative electrode material of a lithium battery,
The entrance of lithium atoms can be widened, lithium atoms can be easily diffused, and a decrease in discharge capacity can be reduced.

Needless to say, the graphite fine particles are not subjected to mechanical damage such as pulverization. Therefore, it has a large resistance to charge / discharge cycles.

At 25 ° C., the immersion heat of hexane and benzene is 30 mJ / m ² or less, and the immersion heat of n-butanol and tertiary butanol is 60 mJ / m ² , which cannot be obtained by the conventional KS-6. ² or less, the immersion heat of dimethyl sulfoxide is 150 mJ / m ² or less, and the immersion heat of the dotriacontan / hexane solution is 80 mJ / m ^2.
Graphite fine particles having the following heat values and low surface activity are obtained, and when applied as a negative electrode material of a lithium battery, a decrease in discharge capacity can be reduced.

The graphite fine particles obtained as described above are molded under pressure, and the molded graphite particles are used as a negative electrode, and EC / DME / 1 mol LiCl is used as an electrolyte.
Assemble a bipolar cell using O ₄ and Li-Al (20 wt%) as a counter electrode.

The graphite fine particles have an average particle diameter of 10 μm or less, areotropically shaped, are not mechanically damaged, and have a low surface activity. Thus, a lithium battery having low resistance and high resistance to charge / discharge cycles can be obtained.

[0043]

Embodiments will be described below. FIG. 1 is a schematic sectional view of the reaction furnace used in the present embodiment. In the figure, reference numeral 1 denotes a reaction chamber 1, which is formed of a metal material having a transition metal at least partially, such as stainless steel 3 or iron made of a surface coated with a transition metal material 2. 5 is a heater insulated by an alumina insulating plate 4, 6 is a heat insulating material, and the reaction chamber 1 is maintained at a predetermined temperature by a temperature controller (not shown). Reference numeral 7 denotes an inlet of the source gas, and 8 denotes an outlet. The source gas is introduced into the reaction chamber 1 from the inlet 7 and discharged from the outlet 8. Further, the reaction chamber 1 is configured so that a porous body 9 made of transition metals can be arranged. In the following comparative examples, the reaction chamber 1 is formed of alumina.

Embodiments 1 and 2 Table 1 shows the reaction conditions of the present example together with comparative examples, and Table 2 shows the results of outlet gas composition analysis after the reaction. The source gas is H
₂ / CO ₂ , pressure was 1 atm, temperature was 600 to 650 ° C., and a non-humidified dry gas was used.

[0045]

[Table 1]

[0046]

[Table 2]

Carbon deposition was observed under the reaction conditions in which a nickel porous material coexisted. Considering the role of the nickel porous body, as shown in Table 2, the nickel porous body was
It can be seen that the gas shift reaction is promoted.

As shown in Table 2, the water-gas shift reaction rate was almost 1 in Examples 1 and 2 where carbon was deposited.
Although it was close to 00%, it was 50% or less in Comparative Examples 1 and 2 where only carbon deposition was observed. Therefore, it cannot be denied that the water-gas shift reaction rate greatly contributes to carbon deposition. Source gas is H ₂ / CO ₂
Therefore, this water-gas shift reaction generates CO, which is the main role of carbon deposition.

X-ray diffraction of the grown carbon was performed and its crystal structure was confirmed. As shown in FIG. 2, a clear graphite structure was shown. In particular, the characteristic features of this carbon are (002) and (004) as in a normal graphite structure.
In addition to the strong diffraction from the surface, (101) and (10
2) Diffraction from the surface is also strong. The strong diffraction from the oblique surface indicates that the sample has a size sufficient to generate sufficient diffraction intensity, which means that the sample is isotropic (spherical). KS-6 mentioned earlier
Has a plate-like shape, and the diffraction from the (004) plane is weak, and the diffraction from the (101) plane is hardly visible.

The SEM photograph shows that the grown carbon had a spherical shape with an average particle diameter of 0.1 to 0.3 μm, and no mechanical damage was observed. When the BET surface area was measured, it showed a considerably high value of 80 m ² / g. For reference, the BET surface area of KS-6 was 20 m ² / g, which is four times higher than that.

The graphite particles were subjected to immersion heat measurement using ten kinds of organic solvents using a twin calorimeter, and the results shown in Table 3 were obtained. The measured values of KS-6 shown for comparison are also shown, but the graphite fine particles showed a small immersion heat per surface area that cannot be obtained with KS-6. That is, the surface is not very active. This is favorable as a negative electrode material for a lithium battery. This is because if the activity is high, the initial charge capacity is increased, but the discharge capacity is drastically reduced. As a result, the amount of lithium to be stored is also increased. However, since the activity is low, the decrease in the discharge capacity can be reduced.

[0052]

[Table 3]

Embodiments 3 to 5 The source gas is a mixed gas of H ₂ and CO ₂ as in Examples 1 and 2, and the temperature is 50
The pressure was set to 0 to 550 ° C. and the pressure was set to 1 to 5 atm, and a nickel porous body was provided. The reaction conditions and results are shown in Table 4. Deposition of carbon was observed under any of the reaction conditions, but the deposition amount was larger at 5 atm than at 1 atm.
In Example 5 in which carbonate vapor was coexisted, the deposition amount was much larger.

[0054]

[Table 4]

FIG. 3 shows the result of X-ray diffraction of the graphite fine particles obtained in Example 5, which shows that there is no great difference from the samples of Examples 1 and 2.

The vapor of the coexisting carbonate is a mixture of lithium carbonate and potassium carbonate and has a pressure of 10 ^-5 Torr or less. For graphite, the intercalation of alkali metal is well known, and most alkali metal elements such as lithium, sodium, and potassium enter the graphite structure. The composition is represented by C ₆ M (M: alkali metal) with the alkali metal in the highest concentration. Since such C ₆ M X-ray diffraction is also performed, when the alkali metal enters the graphite structure, it can be clearly determined. However, the X-ray diffraction of the graphite sample shown in FIG.
From the results of the line diffraction, it can be determined that lithium and potassium do not enter at all. Therefore, it can be said that the vapor of the coexisting alkali metal carbonate promotes the vapor phase growth of graphite but does not change the graphite structure.

As is evident from Table 4, when the carbonate vapor coexists, the amount of precipitated carbon increases by 20 times as compared with the case where no coexistence exists. This is a great effect in practical use.

Embodiment 6 FIG. When 100% CO gas was used as a raw material gas, the temperature was maintained at 600 ° C. and the pressure was 10 atm, and the gas supply was continued for 50 hours so as to always ensure the pressure drop, and carbon deposition was observed. When X-ray diffraction was performed, a diffraction pattern that was not much different from the results of Examples 1 to 5 was obtained, and it was confirmed that the powder was definitely graphite.

The reaction chamber 1 was an iron container, and a small amount of sodium carbonate was placed on the bottom of the iron container, so that sodium carbonate vapor coexisted in the reaction chamber 1.

A small amount of the graphite sample produced in Example 1 was placed in the reaction chamber 1 in advance. Therefore, it is considered that the generated carbon was generated by using the graphite sample as a seed.

Example 7 Water gas generated at 900 ° C. was introduced into the same iron reaction chamber 1 as in Example 6,
When the supply of water gas was continued at a temperature of 3 ° C. and a pressure of 3 atm to ensure a constant pressure drop, carbon deposition was observed after 100 hours.

A mixture of rubidium carbonate and cesium carbonate was placed at the bottom of the reaction chamber 1, and the vapor was passed through the reaction chamber 1.
Coexisted within. As a result of X-ray diffraction, it was confirmed that the produced carbon sample was pure graphite as in Examples 1 to 6.

Embodiment 8 FIG. In Example 5, carbon was deposited under the same conditions as in Example 5, except that a chromium porous body was used instead of the nickel porous body. X-ray diffraction confirmed that the generated carbon was pure graphite.

Embodiment 9 FIG. FIG. 4 shows a double reactor used in the present embodiment, which is a small stainless steel vessel 1 whose temperature can be controlled independently of the stainless steel reaction chamber 1 shown in FIG.
0 is connected to the reaction chamber 1 by a communication pipe 11, and the temperature of the reaction chamber is set to 6
Sodium carbonate was put into the stainless steel container 10 at 50 ° C., and the temperature was controlled at 800 ° C., so that the vapor pressure of the coexisting carbonate was higher than 650 ° C.

A CO gas (concentration of 80% or more) is introduced into the reaction chamber 1, and the pressure is always maintained at 5 atm.
Gas introduction was continued. After 100 hours, carbon deposition was observed. X-ray diffraction confirmed that the produced carbon was pure graphite.

Embodiment 10 FIG. The graphite fine particles obtained in Examples 1 to 9 were molded under pressure, and the discharge capacity of a lithium battery using the molded graphite particles as a negative electrode was confirmed. EC / DME / 1 mol LiClO ₄ as electrolyte,
Using a Li-Al (20 wt%) as a counter electrode, assembling a bipolar cell, charging the battery at a constant current to 0 V, and discharging it to 1 V, the discharge capacity in each case was 250 mAh /
g was obtained.

[0067]

According to the first aspect of the present invention, graphite particles having an average particle diameter of 10 μm or less and having an isotropic shape are not mechanically damaged. , The entrance of lithium atoms can be widened and lithium atoms can be easily diffused,
A decrease in discharge capacity can be reduced, and furthermore, it has a large resistance to charge / discharge cycles.

According to the second aspect of the present invention, since the surface activity is low with respect to various solvents used for the lithium battery, a decrease in the discharge capacity can be reduced.

According to the third, fourth and fifth aspects of the present invention, graphite fine particles having an average particle diameter of 10 μm or less and having an isotropic shape and not suffering mechanical damage can be produced.

According to the sixth aspect of the invention, the transition metal material is porous and has a wide reaction area, so that the graphitization reaction can be further promoted.

According to the seventh and ninth aspects of the present invention, the graphitization reaction can be further promoted by coexisting the vapor of the alkali metal carbonate in the reaction chamber.

According to the eighth aspect of the present invention, the vapor pressure of the alkali metal carbonate in the reaction chamber can be increased, so that the graphitization reaction can be further promoted.

According to the tenth aspect, prior to the vapor phase growth, the seeds of the graphite fine particles grown in advance are introduced into the reaction chamber, whereby the graphite fine particles are grown on the seeds. In addition, graphite particles of uniform quality can be manufactured.

According to the eleventh and twelfth aspects of the present invention, graphite fine particles having an average particle diameter of 10 μm or less, having an isotropic shape, not receiving mechanical damage, and having a low surface activity are used for a negative electrode of a lithium battery. By using the lithium battery, a lithium battery with a small decrease in discharge capacity and a high resistance to a charge / discharge cycle can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a reactor used in one embodiment of the present invention.

FIG. 2 is an X-ray diffraction result of the graphite fine particles obtained in Examples 1 and 2.

FIG. 3 is an X-ray diffraction result of the graphite fine particles obtained in Example 5.

FIG. 4 is a schematic view of a double reactor according to one embodiment of the present invention.

[Explanation of symbols]

1 reaction chamber, 2 transition metal materials, 3 stainless steel, 4
Alumina insulating plate, 5 heater, 6 heat insulating material, 7 entrance, 8 exit, 9 porous body, 10 small container, 11
Communication pipe

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01M 10/40 H01M 10/40 Z

Claims (12)

[Claims] 1. A reaction represented by the following formula (1) or (2) at 700 ° C. or lower: 2CO → CO ₂ + C (precipitation) (1) H ₂ + CO → H ₂ O + C (precipitation) (2) Characterized by having an isotropic shape with an average particle diameter of 10 μm or less. 2. At 25 ° C., the immersion heat of hexane and benzene is 30 mJ / m ² or less, the immersion heat of n-butanol and tertiary butanol is 60 mJ / m ² or less, and the immersion heat of dimethyl sulfoxide is 150 mJ / m 2. ^Two
Hereinafter, the immersion heat of the dotriacontan / hexane solution is 80
^2. The graphite fine particles according to claim 1, having a calorific value of not more than mJ / m < ² > and having a low surface activity. 3. A reaction represented by the following formula (1) or (2) at 700 ° C. or lower: 2CO → CO ₂ + C (precipitation) (1) H ₂ + CO → H ₂ O + C (precipitation) (2) A method for producing graphite fine particles, wherein the fine particles are grown in a vapor phase in a reaction chamber. 4. The method for producing graphite fine particles according to claim 3, wherein a material mainly composed of a transition metal material is used in the reaction chamber or a part of the reaction chamber. 5. The method for producing graphite fine particles according to claim 3, wherein a material mainly composed of a transition metal material is disposed in the reaction chamber. 6. The method for producing graphite fine particles according to claim 4, wherein the transition metal material is a porous material. 7. The method for producing graphite fine particles according to claim 3, wherein vapor of alkali metal carbonate coexists in the reaction chamber. 8. The method according to claim 3, wherein the alkali metal carbonate is stored in a container communicating with the reaction chamber, and the vapor of the alkali metal carbonate generated in the container coexists in the reaction chamber. 7. The method for producing graphite fine particles according to any one of 6. 9. The alkali metal carbonate is lithium carbonate,
The method for producing graphite fine particles according to claim 7 or 8, wherein the method is a simple substance of sodium carbonate, potassium carbonate, rubidium carbonate, or cesium carbonate or a mixture having an arbitrary mixing ratio. 10. The method for producing graphite fine particles according to claim 3, wherein seeds of the graphite fine particles grown in advance are introduced into the reaction chamber prior to the vapor phase growth. 11. A lithium battery using the graphite fine particles according to claim 1 for a negative electrode. 12. The graphite fine particles produced by the method for producing graphite fine particles according to any one of claims 3 to 10,
A lithium battery used as a negative electrode.