JP2002042788A - Lithium secondary battery and manufacturing method for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium secondary battery with excellent charging/ discharging cycle characteristics and having high capacity. SOLUTION: This lithium secondary battery is provided with a negative electrode, a positive electrode and a nonaqueous electrolyte. The negative electrode contains a silicon material for storing and discharging lithium ions, a carbon material, and a compound having boron atoms and silicon atoms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery and a method for manufacturing the same, and more particularly, to a lithium secondary battery having a high capacity and good charge / discharge cycle characteristics by improving a negative electrode and a method for manufacturing the same. It is about the method.

[0002]

2. Description of the Related Art For lithium secondary batteries, improvement of charge / discharge cycle characteristics has been a major research topic. As a solution to this problem, a battery using a carbon material that stores and releases lithium ions in a negative electrode has been proposed and put into practical use. Although this battery is excellent in charge / discharge cycle characteristics, it has not been able to realize a higher capacity than the alloy negative electrode.

Under such circumstances, it has been proposed to use, for the negative electrode, a silicon material which electrochemically alloys with lithium at the time of charging (JP-A-10-255768).
No.). This silicon material has a feature that a higher capacity can be realized than a carbon material.

[0004]

However, since the silicon material has a large volume change (expansion and shrinkage due to occlusion and release of lithium ions) due to charge and discharge, the silicon material itself is pulverized when charge and discharge are repeated. Problem. When the powder is pulverized in this manner, the structure for storing and releasing lithium ions is destroyed, so that the amount of storage and release of the entire negative electrode is reduced. Further, since fine gaps are generated in the negative electrode along with the pulverization, electrons cannot move smoothly, and the deterioration of the current collection rate becomes remarkable in combination with the low electron conductivity of the silicon material itself. Therefore, a secondary battery having sufficient cycle characteristics cannot be configured.

The present invention has been made in view of the above, and an object of the present invention is to provide a high-capacity lithium secondary battery having excellent charge / discharge cycle characteristics and a method for manufacturing the same.

[0006]

Means for Solving the Problems To solve the above problems, the invention according to claim 1 is a lithium secondary battery comprising a negative electrode, a positive electrode, and a non-aqueous electrolyte, wherein the negative electrode comprises: It is characterized by containing a silicon material capable of inserting and extracting lithium ions, a carbon material, and a compound having a boron atom and a silicon atom.

The present inventors have repeated experimental studies on silicon materials capable of increasing the capacity, with a focus on improving the cycle characteristics. As a result, they have found that the use of a silicon material, a carbon material, and a compound having a boron atom and a silicon atom can improve the cycle characteristics without significantly impairing the high capacity of the silicon material, and reached the present invention.
The reason why the cycle characteristics can be improved in this way is not necessarily clear, but is considered to be due to the following reason. That is, a compound having a boron atom and a silicon atom does not occlude and release lithium ions and hardly changes in volume during charge and discharge, and a carbon material occludes and releases lithium ions and has good electron conductivity. By making these exist together with the silicon material in the negative electrode,
It is considered that the pulverization itself is suppressed, and even if the pulverization proceeds, the carbon material does not cause a large decrease in the current collection rate.

[0008] Here, "containing a silicon material capable of inserting and extracting lithium ions, a carbon material, and a compound having a boron atom and a silicon atom" means that the silicon material or the like is present in the negative electrode. It is used in the sense that it can exist in any form such as a mixture, a sintered body, a solid solution, etc., as long as it can be confirmed by X-rays or the like.

According to a second aspect of the present invention, in the first aspect, the compound having a boron atom and a silicon atom is SiB ₆ .

According to the above configuration, since the pulverization of the silicon material is reliably suppressed, a high capacity lithium secondary battery having excellent cycle characteristics can be obtained.

According to a third aspect of the present invention, in the first or second aspect, the silicon material, the carbon material, and the compound having a boron atom and a silicon atom are in a state in which respective powder particles are uniformly dispersed. It is characterized by being present in.

With the above structure, the powder particles of the compound and the powder particles of the carbon material are present in a uniformly dispersed state around the powder particles of the silicon material, which greatly expand and contract upon charge and discharge. A high capacity lithium secondary battery having improved cycle characteristics.

Here, "uniformly dispersed" means that the powder particles of the compound, the powder particles of the silicon material, and the powder particles of the carbon material are present independently without sintering, solid solution, or the like. Dispersed in a substantially uniform state.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the silicon material and the compound having a boron atom and a silicon atom are integrated in a state where these two components are in direct contact with each other. Is present as two-component composite particles.

According to the above configuration, since the silicon material which deteriorates the cycle characteristics and the compound having a boron atom and a silicon atom are integrated, the pulverization is more effectively suppressed. Therefore, a lithium secondary battery having excellent cycle characteristics is obtained as compared with a case where powder particles of a silicon material or the like are uniformly dispersed.

Here, the "binary composite particles" may be in any form as long as a compound having a boron atom and a silicon atom and a silicon material are integrated without interposing a binder or the like. For example, a sintered body obtained by sintering these two components and a solid solution composed of two components are used.

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the silicon material, the carbon material, and the compound having a boron atom and a silicon atom are integrated in a state where these three components are in direct contact. It is characterized in that it exists as ternary composite particles.

According to the above configuration, since the carbon material is integrated in addition to the compound and the silicon material, the electrons can be more smoothly moved by utilizing the good electron conductivity of the carbon material. You can do it. Therefore, better current collection can be performed than when the powder particles of the silicon material or the like are uniformly dispersed or when the two-component composite particles are dispersed, and a lithium secondary battery having excellent cycle characteristics can be obtained.

Here, the "ternary composite particles" may be any compound as long as a compound having a boron atom and a silicon atom, a silicon material and a carbon material are integrated without interposing a binder or the like. It may be in the form of, for example, a sintered body obtained by sintering these three components or a solid solution composed of three components.

According to a sixth aspect of the present invention, there is provided a negative electrode, a positive electrode, and a non-aqueous electrolyte, wherein the negative electrode has a silicon material that absorbs and releases lithium ions, a carbon material, and boron and silicon atoms. A method for producing a lithium secondary battery comprising a compound and a compound, wherein the powder of the silicon material and the powder of a compound having a boron atom and a silicon atom are mixed and heat-treated, and the silicon material and the boron are mixed. A two-component composite particle producing step of producing a powder containing two-component composite particles which are integrated in a state in which the compound having atoms and silicon atoms are integrated in direct contact with each other; It is characterized by comprising a mixed powder preparation step of preparing a mixed powder by mixing powders of materials, and a negative electrode preparation step of preparing a negative electrode using the mixed powder.

According to the above configuration, a lithium secondary battery having high capacity and good cycle characteristics can be easily manufactured.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the temperature of the heat treatment in the step of preparing the two-component composite particles is lower than the melting point of the silicon material.

According to the above configuration, the negative electrode can be manufactured without melting the silicon material that stores and releases lithium ions, so that a lithium secondary battery that makes full use of the high capacity of the silicon material can be manufactured.

The invention according to claim 8 includes a negative electrode, a positive electrode, and a non-aqueous electrolyte, wherein the negative electrode has a silicon material that absorbs and releases lithium ions, a carbon material, and boron and silicon atoms. A method for producing a lithium secondary battery comprising a compound and a compound, wherein the powder of the silicon material and the powder of a compound having a boron atom and a silicon atom are mixed and heat-treated, and the silicon material and the boron are mixed. A two-component composite particle producing step of producing a powder containing two-component composite particles that are integrated in a state where the compound having atoms and silicon atoms are directly contacted, and a powder containing the two-component composite particles, A powder containing three-component composite particles obtained by mixing and heat-treating a powder of a carbon material and heat-treating the silicon material, the carbon material, and a compound having a boron atom and a silicon atom in direct contact with each other. A three-component system composite particle preparation process of manufacturing, characterized by comprising a negative electrode preparation step of producing a negative electrode by using a powder containing the three-component system composite particles.

According to the above configuration, a lithium secondary battery having high capacity and good cycle characteristics can be easily manufactured.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, the heat treatment temperature in the two-component composite particle production step and the three-component composite particle production step is lower than the melting point of the silicon material. It is characterized by temperature.

According to the above configuration, as described above,
A lithium secondary battery utilizing the high capacity of a silicon material can be manufactured.

Next, the present invention will be described.

The negative electrode used in the present invention contains a silicon material that absorbs and releases lithium ions, a carbon material, and a compound having a boron atom and a silicon atom (hereinafter referred to as “boron-based compound”).

As the silicon material, lithium ions are used.
It is not particularly limited as long as it absorbs and releases and has silicon atoms.
However, among them, silicon alone, silicon-lithium alloy (composition formula
Li _XSi; X is more than 0 and not more than 4).
These have a large lithium ion occlusion and release amount,
This is because a high capacity lithium secondary battery is obtained. Above silicon
-For lithium alloys, lithium metal and silicon
Mix in a non-oxidizing atmosphere, and then cool and cool.
It can be obtained by a method of solidifying or the like.

Specific examples of the carbon material include graphite materials such as natural graphite and artificial graphite, as well as carbon black, acetylene black and carbon fiber. Among them, a graphitic material is preferred. This is because the graphitic material has good electron conductivity, so that even if the silicon material is finely divided by repeated charge and discharge, the current collection rate is not significantly deteriorated. Further, since relatively more lithium ions are absorbed and released than other carbon materials, the capacity density of the negative electrode as a whole does not significantly decrease.

The content of the carbon material is preferably at least 5% by mass, more preferably 10 to 60% by mass, based on the total amount of the silicon material and the boron compound. This is because if the amount of the carbon material is too small, the silicon material and the boron-based material tend to have poor electron conductivity, so that electrons tend not to move smoothly.

Specific examples of the boron compound include, for example, SiB ₆ and SiB ₄ . Above all, SiB ₆ is preferable because it can effectively suppress the pulverization of the silicon material due to charge and discharge.

The content ratio (X / Y) of the boron compound (X) and the silicon material (Y) is expressed as follows:
The range of / 95 to 50/50 is preferred. This is because if the amount of the boron-based compound is too large, the amount of the silicon material that occludes and releases lithium ions relatively decreases, and as a result, the capacity of the entire negative electrode decreases. Conversely, when the amount of the boron-based compound is too small, the cycle characteristics are not improved.

The negative electrode used in the present invention can be produced by using the above-mentioned silicon material, carbon material and boron-based compound by, for example, the following three methods.

As a first method, a powder of a boron-based compound, a powder of a silicon material, and a powder of a carbon material are mixed, and then other components such as a binder are added and further mixed. A method of applying to the surface of an electric conductor and drying it is exemplified. According to this method, a negative electrode in which three-component powder particles are uniformly dispersed can be obtained.

As the second method, the following method can be mentioned. That is, first, after mixing the boron-based compound powder and the silicon material powder, a molding step such as pressure molding is performed as necessary. Next, heat treatment is performed, and the powder containing the two-component composite particles formed by integrating the boron-based compound and the silicon material in direct contact with each other is produced by pulverization and sizing. Subsequently, a powder of a carbon material is added to this powder and mixed. Then, after adding other components such as a binder to the obtained mixed powder and mixing, the mixture is applied to the surface of the negative electrode current collector and dried. Thus, a negative electrode can be manufactured.
According to this method, two-component composite particles formed by sintering powder particles of a silicon material and powder particles of a boron-based compound, or two-component composite particles formed by solid-solution of a silicon material and a boron-based compound are used. The resulting negative electrode can be obtained.

Here, the temperature of the heat treatment is preferably lower than the melting point of the silicon material. When heat treatment is performed at such a temperature, the silicon material does not melt, so that the structure for storing and releasing lithium ions is almost completely maintained, and a high-capacity lithium secondary battery can be obtained. In the case where silicon alone is used as the silicon material, the melting point of silicon alone, ie, 1
The heat treatment is preferably performed at a temperature of less than 414 ° C, and more preferably 300 ° C or more and less than 1414 ° C. If the temperature is lower than 300 ° C., it tends to be impossible to integrate. More preferably, the temperature is in the range of 800 to 1300 ° C from the viewpoint of obtaining composite particles integrated in a good state.

The third method is as follows. That is, first, similarly to the second method, after mixing the boron-based compound powder and the silicon material powder,
A molding step such as pressure molding is performed as necessary. Subsequently, heat treatment is performed, and the powder containing the two-component composite particles obtained by integrating the boron-based compound and the silicon material in direct contact with each other is produced by pulverization and sizing. Next, with this powder,
After mixing with the powder of the carbon material and performing a molding step such as pressure molding as necessary, heat treatment is performed, and further crushing and sizing is performed, so that the boron compound, the silicon material and the carbon material are in direct contact with each other. In this state, a powder containing the three-component composite particles that are integrated is produced. Then, after adding other components such as a binder to the obtained powder and mixing, the mixture is applied to the surface of the negative electrode current collector and dried. Thus, a negative electrode can be manufactured. According to this method, ternary composite particles obtained by sintering boron-based compound powder particles, silicon material powder particles, and carbon material powder particles, or boron-based compound, silicon material, and silicon material are solidified. A negative electrode containing the ternary composite particles dissolved can be obtained.

Here, the respective temperatures of the heat treatment are as follows:
For the same reason as in the second method, a temperature lower than the melting point of the silicon material is preferable in any case.

The non-aqueous electrolyte used in the present invention contains water.
There is no particular limitation as long as it is not liquid, solid, gel
Any form may be used. As a specific example,
Tylene carbonate, propylene carbonate, butylene
Cyclic carbonates such as carbonates and dimethyl carbonate
Carbonate, methyl ethyl carbonate, diethyl carbonate
Mixed solvents with chain carbonates such as
Carbonate, 1,2-dimethoxyethane, 1,2-
Solvents such as mixed solvents with ether solvents such as diethoxyethane
LiPF in various non-aqueous solvents₆, LiBF_Four, LiC
F_ThreeSO_Three, LiN (CF_ThreeSO_Two)_Two, LiN (C_Two
F_FiveSO_Two)_Two, LiN (CF_ThreeSO_Two) (C_FourF₉S
O_Two), LiC (CF_ThreeSO_Two)_Three, LiC (C_TwoF_Five
SO_Two)_Three Or a solution containing two or more of these
Is raised. In addition, polyethylene oxide, polyac
Electrolyte was retained in polymer skeleton such as rilonitrile
Structured gel electrolyte, LiI, Li_ThreeSuch as N
An inorganic solid electrolyte can also be used.

The positive electrode used in the present invention is not particularly limited as long as it contains a positive electrode active material, and various conventionally known positive electrodes can be used. Specific examples of the positive electrode active material include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ ,
LiMnO ₂ , LiCo _0.5 Ni _0.5 O ₂ , LiNi _0.7
Examples thereof include a transition metal oxide having Li such as Co _0.2 Mn _0.1 O ₂ and a metal oxide having no Li such as MnO ₂ .

The shape of the lithium secondary battery of the present invention is not particularly limited as long as it includes the above-described negative electrode, positive electrode, and non-aqueous electrolyte. Can be taken.

[0044]

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

Example 1 FIG. 1 is a schematic diagram showing an outline of a triode type glass cell for evaluating the charge / discharge cycle characteristics of a lithium secondary battery of the present invention. A working electrode 2 and a counter electrode 3 are installed in a glass container 1 of this triode glass cell in a state where the working electrode 2 and a counter electrode 3 face each other via a polypropylene separator (not shown). Has been immersed. The reference electrode 5 is provided in the glass tube 6 connected to the lower right wall of the container 1, and the container 1 and the glass tube 6 communicate with each other through the communication tube 7. Note that reference numeral 8
Is a lid for sealing the container 1. Hereinafter, the content of each member will be described.

(Preparation of working electrode) First, Si powder (average particle size: 10 μm) and SiB ₆ powder (average particle size: 20 μm)
And artificial graphite powder (average particle size: 20 μm) with 10:
Negative electrode powder a1 was prepared by weighing to a mass ratio of 1:11 and mixing in a mortar. Then, 90 parts by mass (hereinafter abbreviated as “parts”) of the negative electrode powder a1 and 1 part of a fluororesin (polytetrafluoroethylene) as a binder were added.
0 parts was mixed to prepare a negative electrode material. Then, this negative electrode material was applied to the surface of a current collector made of copper to prepare a working electrode.

(Preparation of Counter Electrode) A lithium foil was pressed against a copper foil to prepare a counter electrode.

(Preparation of Reference Electrode)
That is, a lithium foil was pressed against a copper foil to produce a reference electrode.

(Preparation of Non-Aqueous Electrolyte) Lithium is added to an equal volume mixed solvent of ethylene carbonate and diethyl carbonate.
The PF ₆ was prepared 1 mol / liter and dissolved to non-aqueous electrolyte solution.

(Preparation of Triode Glass Cell) The nonaqueous electrolyte was poured into a glass container 1 and the working electrode 2 and the counter electrode 3 were arranged so as to face each other with a polypropylene separator interposed therebetween. Established. Further, the above-mentioned reference electrode 5 was disposed in a glass tube 6. Thus, the three-electrode glass cell A1 shown in FIG. 1 was produced.

Example 2 First, Si powder and SiB ₆
The powder was weighed so as to have a mass ratio of 10: 1 and mixed in a mortar, and the mixed powder was press-molded with a mold having a diameter of 17 mm. Then, in a non-oxidizing atmosphere, 10
Baking at 00 ° C. for 24 hours, pulverizing the obtained product in a mortar, and powder containing binary composite particles (average particle size: 10 μm)
I got

Next, the powder 5 obtained as described above was prepared.
0 parts and 50 parts of artificial graphite powder were mixed to prepare a negative electrode powder a2. Then, 90 parts of the negative electrode powder a2 and 10 parts of polytetrafluoroethylene were mixed to prepare a negative electrode material. A three-electrode glass cell A2 was produced in the same manner as in Example 1 except that the negative electrode material was produced in this manner.
Was prepared.

Example 3 First, a powder containing binary composite particles was obtained in the same manner as in Example 2. Next, 50 parts of this powder and 50 parts of artificial graphite powder were mixed, and the mixed powder was pressed and molded, and then baked at 1000 ° C. for 24 hours in a non-oxidizing atmosphere. After pulverization, a powder containing ternary composite particles (average particle size of 20
μm), which was designated as negative electrode powder a3. And
90 parts of this negative electrode powder a3 and 10 parts of polytetrafluoroethylene were mixed to prepare a negative electrode material.
A triode glass cell A3 was produced in the same manner as in Example 1, except that the negative electrode material was produced in this manner.

Comparative Example 1 A powder containing binary composite particles obtained in the same manner as in Example 2 was used as a negative electrode powder b1, and 90 parts of this powder b1 and 10 parts of polytetrafluoroethylene were used. Was mixed as described above to produce a negative electrode material.
A triode glass cell B1 was produced in the same manner as in Example 1, except that the negative electrode material was produced in this manner.

Comparative Example 2 50 parts of SiB ₆ powder and 50 parts of artificial graphite powder were mixed to obtain a mixed powder, which was used as a negative electrode powder b2. Then, 90 parts of this powder b2 and 10 parts of polytetrafluoroethylene were mixed to prepare a negative electrode material. A triode glass cell B2 was produced in the same manner as in Example 1 except that the negative electrode material was produced in this manner.
Was prepared.

Comparative Example 3 50 parts of Si powder and 50 parts of artificial graphite powder were mixed to obtain a mixed powder.
It was set to 3. Then, 90 parts of this powder b3 and 10 parts of polytetrafluoroethylene were mixed to prepare a negative electrode material. A triode glass cell B3 was produced in the same manner as in Example 1, except that the negative electrode material was produced in this manner.

[Comparative Example 4] A powder consisting of artificial graphite alone was used as a negative electrode powder b4, and 90 parts of this powder b4 and 10 parts of polytetrafluoroethylene were mixed to prepare a negative electrode material. A triode glass cell B4 was produced in the same manner as in Example 1, except that the negative electrode material was produced in this manner.

Each of the tripolar glass cells produced as described above was evaluated by the following method.

(Cycle Characteristics) At 25 ° C., the battery was charged to 0 V at a current value of 0.5 mA / cm ² and then discharged to 2 V. This was defined as one cycle of charge and discharge. Then, the charge and discharge were performed for 50 cycles, and the discharge capacity per negative electrode powder was determined. The results are shown in Table 1 below and FIG.

(X-ray measurement of negative electrode powder) Negative electrode powders a1, a
X-ray measurement was performed on 2, a3, b1, b2, b3, and b4, and the confirmed substances were also shown in Table 1 below.

[0061]

[Table 1]

From the results shown in Table 1 and FIG. 2, the cells A1 and A2 using the negative electrode material containing Si, artificial graphite and SiB ₆ were obtained.
2 and A3 were found to have higher capacity and better charge / discharge cycle characteristics than the other cells B1 to B4 that did not contain at least one of the three components. It was also found that the cycle characteristics were improved in the order of cells A1, A2, and A3.

Further, from the cells B1 and B3, it was found that the cycle characteristics could not be improved with the combination of the boron compound and the silicon material or the combination of the carbon material and the silicon material. It is considered that this is because electron conductivity is poor without a carbon material, and pulverization of a silicon material cannot be sufficiently suppressed without a boron-based material.

[0064]

As described above, according to the present invention, it is possible to provide a lithium secondary battery having a high capacity and excellent charge / discharge cycle characteristics, which has not been achieved conventionally, using a silicon material. Therefore, the present invention can be used for electric equipment requiring high energy, which cannot be applied conventionally, and can further contribute to the reduction in size and weight of various electric equipment.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an outline of a three-electrode glass cell.

FIG. 2 is a graph showing the relationship between the discharge capacity per negative electrode powder and the number of cycles.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Working electrode 3 Counter electrode 5 Reference electrode 6 Glass tube 7 Communication tube 8 Lid

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Nori Ikukawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. F-term (reference) 5H029 AJ03 AJ05 AK02 AK03 AL11 AL12 AM03 AM04 AM05 AM07 CJ02 CJ08 CJ28 DJ08 DJ16 EJ03 HJ14 5H050 AA07 AA08 BA16 CA05 CA08 CA09 CB11 CB12 DA03 DA09 EA01 FA17 GA02 GA10 GA27 HA14

Claims (9)

[Claims] 1. A lithium secondary battery comprising a negative electrode, a positive electrode, and a non-aqueous electrolyte, wherein the negative electrode comprises a silicon material that absorbs and releases lithium ions, a carbon material, and a compound having boron atoms and silicon atoms. And a lithium secondary battery. 2. The lithium secondary battery according to claim 1, wherein the compound having a boron atom and a silicon atom is SiB ₆ . 3. The silicon material, the carbon material, the compound having a boron atom and a silicon atom, wherein the respective powder particles are present in a uniformly dispersed state.
The lithium secondary battery according to the above. 4. The two-component composite particle wherein the silicon material and the compound having a boron atom and a silicon atom are present in a state where the two components are integrated in direct contact with each other. Lithium secondary battery. 5. The compound having a silicon material, a carbon material, a boron atom and a silicon atom, which is present as ternary composite particles formed by integrating these three components in direct contact with each other. Or the lithium secondary battery according to 2. 6. A negative electrode, a positive electrode, and a non-aqueous electrolyte, wherein the negative electrode contains a silicon material capable of inserting and extracting lithium ions, a carbon material, and a compound having a boron atom and a silicon atom. A method of manufacturing a lithium secondary battery, comprising mixing a powder of the silicon material with a powder of a compound having a boron atom and a silicon atom and heat treating the mixture to obtain a compound having the silicon material and a boron atom and a silicon atom. A two-component composite particle producing step of producing a powder containing the two-component composite particles that are integrated in a state where they are in direct contact with each other; and mixing the powder containing the two-component composite particles with the carbon material powder. A mixed powder producing step of producing a mixed powder; a negative electrode producing step of producing a negative electrode using the mixed powder;
A method for manufacturing a lithium secondary battery, comprising: 7. The method for producing a lithium secondary battery according to claim 6, wherein the temperature of the heat treatment in the step of producing the two-component composite particles is lower than the melting point of the silicon material. 8. A negative electrode, a positive electrode, and a non-aqueous electrolyte, wherein the negative electrode contains a silicon material capable of inserting and extracting lithium ions, a carbon material, and a compound having a boron atom and a silicon atom. A method of manufacturing a lithium secondary battery, comprising mixing a powder of the silicon material with a powder of a compound having a boron atom and a silicon atom and heat treating the mixture to obtain a compound having the silicon material and a boron atom and a silicon atom. A two-component composite particle producing step of producing a powder containing the two-component composite particles that are integrated in a state where they are in direct contact with each other; and mixing the powder containing the two-component composite particles with the carbon material powder. Heat treatment to produce a powder containing ternary composite particles in which the silicon material, the carbon material, and the compound having boron atoms and silicon atoms are integrated in direct contact with each other. Manufacturing process and the three-component system method for producing a lithium secondary battery and the negative electrode preparation step of producing a negative electrode by using a powder containing composite particles, comprising the. 9. The method for manufacturing a lithium secondary battery according to claim 8, wherein the temperature of the heat treatment in the two-component composite particle production step and the three-component composite particle production step is lower than the melting point of the silicon material. .