JP5626073B2 - Negative electrode material for non-aqueous electrolyte secondary battery and method for producing the same, negative electrode and non-aqueous secondary battery - Google Patents

Description

  The present invention relates to a negative electrode material for a non-aqueous electrolyte secondary battery, a negative electrode for a non-aqueous electrolyte secondary battery using the negative electrode material, and a non-aqueous electrolyte secondary battery using the negative electrode for the non-aqueous electrolyte secondary battery.

  In recent years, with the miniaturization of electronic devices, high-capacity secondary batteries have become necessary. In particular, non-aqueous solvent type lithium secondary batteries having higher energy density are attracting attention as compared with nickel / cadmium and nickel / hydrogen batteries. Conventionally, a high capacity of a lithium secondary battery has been widely studied. However, in recent years, the performance required for the battery has been advanced, and a further increase in capacity is required.

  As a negative electrode material for a lithium secondary battery, graphite and the like have been studied so far. Graphite has been used because of its excellent cycle characteristics, small electrode expansion, and low cost. However, the negative electrode material made of graphite has a limit of theoretical capacity of 372 mAh / g, and further increase in capacity cannot be expected. Therefore, in recent years, studies have been made on alloy-based negative electrodes such as Si, Sn, and Al that form an alloy with lithium having a large theoretical capacity instead of the graphite negative electrode. In particular, since Si has a high capacity, many attempts have been made to apply it as a negative electrode. However, the Si-based negative electrode has a drawback that it has a large volume expansion upon reaction with lithium, Si is pulverized, is easily peeled off from the current collector, is highly reactive with the electrolyte, and has poor cycle characteristics. For this reason, the realization of the negative electrode with small electrode expansion | swelling which was excellent in cycling characteristics, the reactivity with electrolyte solution was suppressed, utilizing the high capacity | capacitance of an alloy type negative electrode is calculated | required.

In Patent Document 1, when amorphous Si particles are used, the inside of the particles becomes homogeneous, the chemical reaction associated with charging / discharging occurs uniformly, and even when the charging / discharging reaction proceeds, non-homogenization is unlikely to occur. And the exfoliation from the current collector are suppressed, and obtaining a negative electrode material having excellent cycle characteristics is described.
Patent Document 2 describes that a lithium secondary battery having high capacity and excellent cycle characteristics can be obtained by heating silicon oxide powder in nitrogen gas and partially nitriding it to obtain SiNxOy powder. .

In Patent Document 3, by using a thin film electrode formed by depositing Si or the like on a copper foil substrate by vapor deposition or sputtering, the electrical resistance is low, the current collecting property is high, and the charge / discharge characteristics are excellent with high voltage and high capacity. Obtaining a lithium secondary battery is described.
Patent Document 4 includes a compound having a phase in which element Z is present in a non-equilibrium state in Si in a composition represented by at least powdered SiZxMy having on the particle surface. It is at least one, and the element M is described as obtaining a negative electrode material characterized in that it is one or more elements selected from elements other than Si and element Z.

JP 2008-123814 A JP 2002-356314 A Japanese Patent Laid-Open No. 11-135115 International Publication No. 2006/123601

  However, according to the study by the present inventors, utilization of a Si-based negative electrode material having a high capacity is desired along with an increase in the necessity for further increasing the capacity of batteries in recent years. There is a problem like this. The irreversible capacity accompanying the reaction with the electrolytic solution increases, consuming lithium in the positive electrode active material, and as a result, the battery capacity decreases. The pulverization of Si deteriorates due to expansion / contraction due to insertion / extraction of lithium and peeling from the current collector. During the cycle, a new surface is generated along with the Si pulverization, whereby the reaction with the electrolytic solution proceeds, the amount of the active material that can be charged and discharged is reduced, and the cycle characteristics are deteriorated. Then, electrode expansion due to insertion of lithium accumulates during the cycle, leading to an increase in battery volume, that is, a decrease in battery capacity per volume.

Therefore, in further increasing the capacity of the lithium secondary battery, not only the capacity is increased by using the Si-based active material, but also the reaction with the electrolyte is suppressed, and the charge and discharge efficiency is improved in the initial stage and in the cycle. There is a strong demand to improve cycle characteristics and suppress an increase in electrode expansion after cycling.
However, since the amorphous Si particles disclosed in Patent Document 1 are Si-Si bonds, the volume expansion of Si accompanying charge / discharge is large, and it is difficult to sufficiently suppress active material cracking and pulverization. And the reactivity with the electrolyte on the surface still exists and is insufficient to improve the cycle characteristics.

In Patent Document 2, partially nitrided silicon oxide powder SiNxOy is obtained using SiOZ as a raw material, but the content of oxygen capable of reacting with Li is large, the initial charge / discharge efficiency is lowered, and the battery capacity cannot be increased. There are challenges.
In Patent Document 3, Si is deposited by a vapor deposition method or a sputtering method to suppress the disconnection of the conductive path with the current collector and improve the charge / discharge characteristics. However, the reactivity of Si with the electrolytic solution is improved. Is not suppressed, the cycle characteristics are insufficient, and there is a problem in productivity because the film is formed by a sputtering method having a low film formation rate.

  In Patent Document 4, although the composition range represented by SiZxMy is widely described as 0.05 <x <0.91, the substantial range of x is 0.18 or more, and the average particle size The importance of the compositional selectivity is not stated, and according to the study by the inventors, the negative electrode material obtained by the production method disclosed in Patent Document 4 is insufficient in battery characteristics. It was necessary to optimize the average particle size and the composition ratio by devising the manufacturing method.

  Accordingly, the present invention has been made in view of such background art, and has a high discharge capacity, high charge / discharge efficiency in the initial stage and in the cycle, excellent cycle characteristics, and non-aqueous water in which electrode expansion after the cycle is suppressed. It aims at providing the negative electrode material for nonaqueous electrolyte secondary batteries and the negative electrode for nonaqueous electrolyte secondary batteries which can provide an electrolyte secondary battery, and the nonaqueous electrolyte secondary battery using these.

  As a result of intensive studies to solve the above problems, the inventors of the present invention, among non-aqueous electrolyte secondary battery negative electrode materials containing Si, particularly include a non-aqueous electrolyte containing a compound SiZxMy (particles) that satisfies the following conditions. Succeeded in producing a secondary battery negative electrode material (particles), and by using it, the discharge capacity is high, the initial and cycle charge / discharge efficiency is high, the cycle characteristics are excellent, and the electrode expansion after cycle is The present inventors have found that a suppressed lithium ion secondary battery can be obtained and have reached the present invention.

That is, the gist of the present invention resides in a negative electrode material for a non-aqueous electrolyte secondary battery containing a compound SiZxMy composed of Si, element Z and element M satisfying the following conditions (1) to ( 7 ).
(1) The element Z is at least one of C and N.
(2) The range of x is 0.01 ≦ x ≦ 0.18.
(3) Element M is one or more elements selected from elements other than Si and element Z.
(4) The range of y is 0.01 ≦ y ≦ 0.35.
(5) The average particle diameter (D50) is 50 nm or more and 20 μm or less.
(6) An amorphous structure. (7) The half width of the Si (111) surface measured by X-ray diffraction is 6 degrees or more.

  The negative electrode material (particle) for a non-aqueous electrolyte secondary battery according to the present invention suppresses expansion of the negative electrode material, and thereby has an effect of suppressing breakage of the conductive path due to active material cracking due to expansion and contraction and crack generation in the electrode. is there. At the same time, the element Z composed of C and / or N is distributed in a specific amount of Si in the Si having high reactivity with the electrolytic solution to have a specific average particle diameter, thereby effectively reducing the activity of Si, Providing high-performance nonaqueous electrolyte secondary batteries that suppress liquid reactivity, have high discharge capacity, high initial and cycle charge / discharge efficiency, excellent cycle characteristics, and suppressed electrode expansion after cycling can do. Moreover, the negative electrode for nonaqueous electrolyte secondary batteries and the nonaqueous electrolyte secondary battery of this invention can be used suitably in various fields, such as an electronic device to which a nonaqueous electrolyte secondary battery is applied.

It shows TEM images of SiC _0.12 O _0.15 particles (bright field) It shows TEM images of SiC _0.12 O _0.15 particles (dark field)

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.
[1] Anode material for nonaqueous electrolyte secondary battery The anode material for a nonaqueous electrolyte secondary battery of the present invention contains a compound SiZxMy composed of Si, element Z, and element M satisfying the following conditions (1) to (6). This is a negative electrode material for a non-aqueous electrolyte secondary battery. (1) The element Z is at least one of C and N.
(2) The range of x is 0.01 ≦ x ≦ 0.18.
(3) Element M is one or more elements selected from elements other than Si and element Z.
(4) The range of y is 0.01 ≦ y ≦ 0.35.
(5) The average particle diameter (D50) is 50 nm or more and 20 μm or less.
(6) An amorphous structure.

Hereinafter, the powdered negative electrode material containing the compound SiZxMy of the present invention may be referred to as “negative electrode material particles of the present invention”. A negative electrode is obtained by using the negative electrode material particles of the present invention as a negative electrode active material and providing a current collector with a layer containing the negative electrode active material.
Such negative electrode material particles of the present invention are extremely useful as a negative electrode active material in non-aqueous electrolyte secondary batteries such as positive and negative electrodes capable of inserting and extracting lithium ions, and lithium secondary batteries equipped with an electrolyte. For example, the non-aqueous electrolyte 2 is composed of a negative electrode material particle of the present invention as a negative electrode active material and a combination of a metal chalcogenide-based positive electrode for a lithium secondary battery that is normally used and an organic electrolyte mainly composed of a carbonate-based solvent. The secondary battery has a large capacity, a small irreversible capacity observed in the initial cycle, excellent cycle characteristics, suppression of electrode expansion after cycling, and high battery storage and reliability when left at high temperatures. It is extremely excellent in efficient discharge characteristics and discharge characteristics at low temperatures.

[Compound SiZxMy]
The compound SiZxMy in the present invention is a particle and is not particularly limited as long as the following conditions (1) to (6) are satisfied.
(1) The element Z is at least one of C and N.
(2) The range of x is 0.01 ≦ x ≦ 0.18.
(3) Element M is one or more elements selected from elements other than Si and element Z.
(4) The range of y is 0.01 ≦ y ≦ 0.35.
(5) The average particle diameter (D50) is 50 nm or more and 20 μm or less.
(6) An amorphous structure.

<Element Z of Compound SiZxMy>
The element Z in the compound SiZxMy is at least one of C and N, preferably C.
The reason why C and N elements are used for the element Z is that by introducing a Si-Z bond stronger than the Si-Si bond, the volume expansion of the active material associated with charging / discharging is suppressed, and the active material cracking and conductivity associated therewith are suppressed. It is possible to suppress the path cut. At the same time, the C and N elements are elements that can form SiaZp (where a and p are integers) that exist in equilibrium with a composition closest to Si and have a higher melting point than Si. Since the melting point compound is generally a stable compound having a negative free energy for generation and having a higher melting point than Si, the activity on the surface of the Si anode material particles can be effectively reduced if the melting point is higher than that of Si. This is because the reactivity with the liquid is suppressed.

<Element M of Compound SiZxMy>
The element M of the compound SiZxMy is one or more elements selected from elements other than Si and the element Z, and is preferably Group 4, Group 5, Group 6, Group 8, Group 9, Group 10 of the periodic table , 11 or 13 and 16 or more elements, more preferably Ti, Zr, V, Cr, W, B, O elements, more preferably Si- They are Ti, Zr, W, and O elements in that they have stronger Si-M bonds than Si bonds. Among these, the O element is particularly preferable in that it is easily incorporated into the present compound during the production process of SiZxMy.

<Composition of Compound SiZxMy>
In the compound SiZxMy, x of SiZxMy is 0.01 ≦ x ≦ 0.18, preferably 0.02 or more, more preferably 0.03 or more, still more preferably 0.04 or more, and particularly preferably 0.05 or more. It is. Moreover, Preferably it is 0.17 or less, More preferably, it is 0.16 or less, More preferably, it is 0.15 or less.

On the other hand, the range of y is 0.01 ≦ y ≦ 0.35, preferably 0.02 or more, more preferably 0.03 or more, still more preferably 0.04 or more, and particularly preferably 0.05 or more. . Further, it is preferably 0.34 or less, more preferably 0.33 or less, still more preferably 0.32 or less, and particularly preferably 0.31 or less.
When the content of x and / or y with respect to Si increases, the discharge capacity decreases. On the other hand, when the content of x and / or y falls below the above range, the electrode layer containing particles of the negative electrode material particles of the present invention. In some cases, the expansion becomes large, the conductive path is broken, the effect of lowering the surface activity is small, the reactivity with the electrolytic solution cannot be suppressed, and preferable cycle characteristics are difficult to obtain.

In the compound SiZxMy, x + y is usually 0.02 or more, preferably 0.04 or more, more preferably 0.06 or more, still more preferably 0.08 or more, and particularly preferably 0.1 or more. Moreover, it is preferably 0.52 or less, more preferably 0.50 or less, still more preferably 0.48 or less, and particularly preferably 0.46 or less. When x + y is too large, the capacity decreases, and when x + y is too small, an amorphous structure is not formed. Therefore, there is a tendency that deterioration due to volume expansion associated with charge / discharge is difficult to prevent.

The x and y composition of the compound SiZxMy is obtained by measuring the ratio (mass%) of Si, Z and M in the sample by the following elemental analysis method, converting the value to atomic%, and further setting Si to 1. The x and y compositions are determined by converting the Z and M atomic concentration ratios of
[Elemental analysis measurement method]
In the Si analysis, after the raw material is dissolved in an alkali, the acid-dissolved solution is measured by ICP-AES. Oxygen analysis is oxygen nitrogen analyzer, ON analyzer (impulse furnace heating extraction under inert gas atmosphere-IR, TCD detection), LECO oxygen nitrogen analyzer TC600), carbon analysis is carbon sulfur analyzer CS analyzer ( It can be measured using a high frequency furnace combustion-IR detection method, carbon sulfur analyzer CS600 manufactured by LECO.

[Structure of Compound SiZxMy]
The structure of the compound SiZxMy of the present invention is a SiZxMy composition in which elements Z and M are dispersed in Si powder particles, and is in an amorphous state in which a crystalline domain cannot be confirmed by transmission electron microscope (TEM) observation, that is, non-crystalline. It can be confirmed that a crystalline structure exists (see FIGS. 1 and 2).

<Amorphous state of compound SiZxMy>
The amorphous state of the compound SiZxMy is determined by the following X-ray diffraction measurement method, and can also be defined as follows.
In the fine particles represented by SiZxMy, the half width of the Si (111) plane measured by X-ray diffraction is usually 6 degrees or more, preferably 6.2 degrees or more, more preferably 6.4 degrees or more, and further Preferably it is 6.6 degrees or more, and particularly preferably 6.8 degrees or more. If the full width at half maximum is too small, it means that the crystallinity is high, and it tends to be difficult to avoid cycle deterioration associated with volume expansion during charge / discharge. Moreover, it is usually 20 degrees or less.

The crystallite size is a value calculated based on Scherrer's equation using the half width. Being amorphous means that the crystallite size has a smaller value. The crystallite size is usually 1.36 nm or less, preferably 1.32 nm or less, more preferably 1.28 or less, still more preferably 1.24 or less, and particularly preferably 1.20 or less. Moreover, it can define as follows also by a Raman spectroscopy measurement method. In fine particles represented by SiZxMy, Raman shift is measured by Raman spectroscopy is in the range of ^{250cm -1 ~500cm} -1.

[X-ray diffraction measurement method]
The half width of the Si (111) plane of the compound SiZxMy in the X-ray diffraction measurement is set, for example, by setting the compound SiZxMy of the present invention on the irradiated surface, and using, for example, an X-ray diffractometer (“X'PertPro MPD” manufactured by PANalytical) Measured. As measurement conditions, measurement is performed in a range of 2θ = 5 to 70 degrees with a concentrated optical system. Background correction is performed by a curve fitting method. After background correction, curve fitting is performed on a peak corresponding to the Si (111) plane with 2θ of 28.4 degrees, the half width of the peak is obtained, and the value after correction by an external standard is calculated as the compound SiZxMy. The full width at half maximum.
The definition of the half width used here is as follows.

The peak intensity corresponding to the Si (111) plane with 2θ of 28.4 degrees is measured, and the peak width corresponding to half of the peak intensity is assumed to be before the half-value width W correction. As an external standard, the half-value width W standard of the Si (111) plane (2θ = 28.4 degrees) of single crystal silicon is measured, and the half-value width W (SiZxMy) of SiZxMy = W before correction−W standard.
[Raman spectroscopy]
Using a Raman spectroscope (for example, Thermo Fisher Scientific's Nicolet Almega XR), the compound SiZxMy of the present invention is set in a measurement cell, and measurement is performed by irradiating laser light with an excitation wavelength of 532 nm (resolution 10 cm ⁻¹ ). Perform background correction of the measured Raman spectrum. In the background correction, the peak start points are connected by a straight line, the background is obtained, and the value is subtracted from the peak intensity.

<Distribution state of elements Z and M in the compound SiZxMy>
The element Z in the compound SiZxMy of the present invention exists at a level of 5 nm or less, such as atoms, molecules, or clusters, and the distribution state of the elements Z and M is preferably uniform in SiZxMy. . When the distribution of the element Z in the SiZxMy layer on the surface of the compound SiZxMy of the present invention is non-uniform and the element Z is present locally, it is difficult to reduce the volume expansion of the compound SiZxMy of the present invention. Moreover, since the activity of the negative electrode material cannot be lowered uniformly, the reactivity with the electrolytic solution cannot be suppressed, and it may be difficult to obtain preferable cycle characteristics. The dispersion state can be confirmed by TEM measurement or the like as shown in the examples described later.

<Average particle diameter (D50)>
As the volume-based average particle diameter (D50), the volume-based average particle diameter (D50) is measured with a laser diffraction particle size distribution analyzer (for example, “LA-920” manufactured by Horiba, Ltd.) using ion-exchanged water as a dispersion medium. A value obtained by measuring can be used. In Examples described later, the volume-based average particle diameter (D50) is obtained by this method.

  The average particle diameter (D50) of the compound SiZxMy of the present invention is 50 nm or more, preferably 80 nm or more, and 20 μm or less, preferably 18 μm or less. If the average particle size (D50) of the compound SiZxMy is below this range, the particle size is too small. Is difficult to remove, and the cycle characteristics may deteriorate. On the other hand, if it exceeds this range, active material cracking due to volume expansion is prominent, and the conductive path is broken. Further, when the negative electrode active material layer is produced on the current collector by coating as described later, the electrode layer tends to become uneven.

[Production method]
The compound SiZxMy of this invention can be manufactured with the manufacturing method etc. which are mentioned below.
<Raw material>
Of the raw materials of the compound SiZxMy, for example, crystalline Si, polycrystalline Si, amorphous Si, silicon compounds (silicon nitride, silicon carbide, etc.), etc. can be used. Preferred are crystalline Si, polycrystalline Si, and amorphous Si, and these are 1600-2.
Since it has a vapor pressure at 500 ° C., it is preferable as a raw material.

As the raw material for the element Z, the raw materials for the C and N elements can be used separately or simultaneously. For example, the raw material for element C is natural graphite, artificial graphite, amorphous carbon, coke, carbide or the like. Among these, it is preferable to use a material having high purity and low cost, such as natural graphite and coke.
Examples of the N element material include nitrides. When the raw material is a gas, a gas containing C (CH ₄ , C ₂ H ₆ , C ₃ H _8, etc.) is used as the C element raw material, and a N containing gas (NH ₃ ) is used as the N element raw material. , N ₂ etc.) can be used. Among these, those that are relatively inexpensive are preferable, and in the case of C, CH ₄ , and in the case of N, N ₂ .

In addition, as a raw material of these elements M, it is preferable to use, for example, a powder, a granule, a pellet, a lump, a plate, or the like, or a gas made of the M raw material as long as it is solid. Specifically, H ₂ O, O _2, CO, and CO ₂ that are inexpensive and can be easily introduced are preferable, and CO and CO ₂ are more preferable.
Examples of the raw material for the solid element M include SiO, SiO ₂ , Si—Ti alloy, Si—Zr alloy, and Si—W alloy. Among these, SiO and SiO ₂ are preferable. Since these have a vapor pressure at 1600-2300 ° C., they are suitable as raw materials.

A single compound (or element) combining Si and element Z may be used as a raw material, or a plurality of compounds. Of these, silicon nitride and silicon carbide are preferred. A single compound combining Si, element Z, and element M may be used, or a plurality of compounds may be used.
<Process>
Although there is no restriction | limiting in particular in manufacturing the compound SiZxMy of this invention, The following manufacturing processes are preferable.

As an example, there is a method in which a Si raw material is melted under vacuum, evaporated and vaporized, and rapidly cooled and condensed in an opposing cooling unit.
Specifically, it is the following process.
Step (1) The Si raw material is melted under vacuum.
Step (2) The molten Si raw material is evaporated and vaporized.
Step (3) While introducing the element M, the vaporized Si raw material is rapidly cooled and condensed in the opposing cooling section.
Step (4) The compound SiZxMy attached to the opposing cooling part is made into particles.

· Step vacuum for (1) is usually ^5x10 -2 torr or less, preferably ^8x10 -2 torr or less, more preferably ^1x10 -3 torr or less. When the degree of vacuum is too low, plasma is generated and vapor deposition performed in the step (2) tends to be impossible.
The melting temperature is usually 1430 ° C. or higher, preferably 1440 ° C. or higher, more preferably 1450 ° C. or higher, and still more preferably 1460 ° C. or higher. Moreover, it is 1500 degrees C or less normally, Preferably it is 1490 degrees C or less, More preferably, it is 1480 degrees C or less. When the temperature is too low, Si is not melted, and when the temperature is too high, there is a tendency to evaporate.

At this time, it is preferable to introduce the element Z before the material is melted. Specifically, a method of mixing the element Z simultaneously with the Si raw material, and a method such as using a graphite crucible used when melting the Si raw material as a C element source in addition to the method of mixing as a raw material if it is a C element It introduces using.
-About a process (2) A vacuum degree is 5x10 ^<-2 > torr or less normally, Preferably it is 8x10 ^<-2 > torr or less, More preferably, it is ^{1x10 < -3} > torr or less. If the degree of vacuum is too low, plasma tends to be generated and vapor deposition tends to be impossible. The temperature for evaporating and vaporizing the molten Si raw material is usually 1500 ° C. or higher, preferably 1520 ° C. or higher, more preferably 1540 ° C. As mentioned above, More preferably, it is 1560 degreeC or more. Moreover, it is 3000 degrees C or less normally, Preferably it is 2900 degrees C or less, More preferably, it is 2800 degrees C or less. If the temperature is too low, the vaporization rate of Si tends to be insufficient, and if the temperature is too high, the vaporized Si raw material is solidified at a high rate and composition control tends to be difficult.

-Step (3) The cooling rate at the time of rapidly cooling and condensing the Si raw material is usually 500 ° C / second or more, preferably 600 ° C / second or more, more preferably 700 ° C / second or more, and further preferably 800 ° C / second. As described above, it is particularly preferably 1000 ° C./second or more. If the rapid cooling rate is too slow, crystallization proceeds and it tends to be difficult to prevent cycle deterioration associated with charge and discharge.

Further, as an atmosphere gas when rapidly cooling condense the vaporized Si _material, H 2 _O, it is preferable that O 2, CO or CO ₂ gas is included. One or more of these may be used simultaneously.
This is because when the atmosphere gas contains H ₂ O, O ₂ , CO, or CO ₂ gas, the oxygen content can be controlled when the M raw material of the SiZxMy composition is oxygen. . Of these, CO and / or CO ₂ gas is preferable.

  The amount of gas to be introduced is usually 1 SCCM or more, preferably 2 SCCM or more, more preferably 3 SCCM or more, still more preferably 4 SCCM or more, and particularly preferably 5 SCCM or more. Further, it is preferably 500 SCCM or less, more preferably 400 SCCM or less, still more preferably 300 SCCM or less, and particularly preferably 200 SCCM or less. If the amount of gas is too small, it becomes difficult to incorporate the element M into the SiZxMy compound. On the other hand, if the amount of gas is too large, a large amount of M component will be contained, and the battery capacity tends to decrease.

In addition to the above, examples of a method of rapidly solidifying after melting using a raw material containing Si and the element Z include a method of further pulverizing after forming a plate material, a wire rod or a powder.
Examples of the method for producing a plate material by rapid solidification include a roll method (roll spinning method, twin roll spinning method), a direct casting and rolling method, and a melt drag method. Moreover, as a method for producing a wire by rapid solidification, a spinning method in a rotating liquid can be used. Furthermore, examples of the method for producing a powder by rapid solidification include a centrifugal spray method, a rotating liquid spray method, a rotating electrode method, a gas spray splat method, a melt extraction method, a melt spinning method, and the like.

Examples of the material of the opposing cooling part include copper and stainless steel, among which copper is preferable in terms of cooling rate.
The compound SiZxMy obtained in the step (3) shows the shape of a flake / powder.
The steps (1) to (3) described above are important steps for producing a compound SiZxMy having a specific amorphous structure.

-About a process (4) If the compound SiZxMy adhering to the opposing cooling part can be grind | pulverized to the said average particle diameter (D50), there will be no restriction | limiting in particular about the grinding | pulverization conditions and the apparatus used for a grinding | pulverization.
For example, jaw crusher, impact crusher, cone crusher and the like are mentioned as the coarse pulverizer, roll crusher and hammer mill are mentioned as the intermediate pulverizer, and ball mill, vibration mill, pin mill, Examples thereof include a stirring mill and a jet mill.

Among these, ball mills, vibration mills, and the like are preferable from the viewpoint of processing speed because the grinding time is short.
The grinding speed varies depending on the type and size of the apparatus. For example, in the case of a ball mill, the grinding speed is usually 50 rpm or more, preferably 100 rpm or more, more preferably 150 rpm or more, and further preferably 200 rpm or more. Moreover, it is 2500 or less normally, Preferably it is 2300 or less, More preferably, it is 2000 or less. If the speed is too high, control of the particle size tends to be difficult, and if the speed is too low, the processing speed tends to be slow.

The grinding time is usually 30 seconds or longer, preferably 1 minute or longer, more preferably 1 minute 30 seconds or longer, and still more preferably 2 minutes or longer. Moreover, it is usually 3 hours or less, preferably 2.5 hours or less, more preferably 2 hours or less. If the pulverization time is too short, the particle size control tends to be difficult, and if the pulverization time is too long, the productivity tends to decrease.
In the case of a vibration mill, the grinding speed is usually 50 rpm or more, preferably 100 rpm or more, more preferably 150 rpm or more, and still more preferably 200 rpm or more. Moreover, it is 2500 rpm or less normally, Preferably it is 2300 rpm or less, More preferably, it is 2000 rpm or less. If the speed is too high, control of the particle size tends to be difficult, and if the speed is too low, the processing speed tends to be slow.

The grinding time is usually 30 seconds or longer, preferably 1 minute or longer, more preferably 1 minute 30 seconds or longer, and further preferably 2 minutes or longer. Moreover, it is usually 3 hours or less, preferably 2.5 hours or less, more preferably 2 hours or less. If the pulverization time is too short, the particle size control tends to be difficult, and if the pulverization time is too long, the productivity tends to decrease.
Moreover, you may perform a classification process as needed.

As conditions for the classification treatment, the opening is usually 53 μm or less, preferably 45 μm or less, more preferably 38 μm or less so as to achieve the above particle diameter.
There are no particular restrictions on the equipment used for classification, but for example, when dry sieving: rotary sieving, oscillating sieving, rotating sieving, vibrating sieving, etc. can be used. : Gravity classifier, inertial classifier, centrifugal classifier (classifier, cyclone, etc.) can be used. For wet sieving: mechanical wet classifier, hydraulic classifier, settling classifier, A centrifugal wet classifier or the like can be used.

[Negative electrode material for non-aqueous electrolyte secondary battery]
The negative electrode material for a non-aqueous electrolyte secondary battery of the present invention only needs to contain at least the above-described compound SiZxMy, and one or two or more kinds may be mixed with another one or two or more kinds of carbon materials. .
When a carbon material is mixed with the compound SiZxMy described above, the mixing ratio of the compound SiZxMy to the total amount of the compound SiZxMy and the carbon material is not particularly limited, but is usually 10% by mass or more, preferably 20% by mass or more, and usually 95%. It is the mass% or less, Preferably it is the range of 90 mass% or less. When the mixing ratio of the compound SiZxMy is less than the above range, the effect of the compound SiZxMy tends to hardly appear. On the other hand, if it exceeds the above range, the characteristics of the carbon material tend to hardly appear.

The carbon material is not particularly limited, and a material selected from natural graphite, artificial graphite, amorphous-coated graphite, and amorphous carbon is used. Any one of these materials may be used alone, or two or more of these materials may be used in any combination and composition.
As natural graphite, for example, highly purified flaky graphite or spheroidized graphite can be used. The volume-based average particle diameter of natural graphite is usually 3 μm or more, preferably 5 μm or more, and usually 40 μm or less, preferably 30 μm or less. The BET specific surface area of natural graphite is usually 1 m ² / g or more, preferably 1.5 m ² / g or more, and usually 10 m ² / g or less, preferably 8 m ² / g or less.

Examples of the artificial graphite include particles obtained by graphitizing a carbon material. For example, particles obtained by firing and graphitizing a single graphite precursor particle while it is powdered can be used.
As amorphous-coated graphite, for example, natural graphite or artificial graphite coated with an amorphous precursor pair and fired, or natural graphite or artificial graphite coated with amorphous by CVD can be used.

As the amorphous carbon, for example, particles obtained by baking resin, particles obtained by baking tar pitch, particles obtained by baking bulk mesophase, particles obtained by infusibilizing a graphitizable binder and baking can be used. .
The apparatus used for mixing the compound SiZxMy and the carbon material is not particularly limited. For example, in the case of a rotary mixer: a cylindrical mixer, a twin cylinder mixer, a double cone mixer, a regular cubic type. For mixers, vertical mixers, fixed mixers: spiral mixers, ribbon mixers, Muller mixers, Helical Flight mixers, Pugmill mixers, fluidized mixers, ball mills, vibrating ball mills Jet mills, hybridizers, mechano-fusions, and the like can be used.

[Negative electrode for non-aqueous electrolyte secondary battery]
The negative electrode for a non-aqueous electrolyte secondary battery of the present invention uses the negative electrode material particles of the present invention as a negative electrode active material. Generally, the negative electrode material particle layer of the present invention is electrically conductive on a current collector. Is provided so as to be secured.
Such a negative electrode of the present invention is extremely useful as a negative electrode in a non-aqueous electrolyte secondary battery such as a positive electrode and a negative electrode capable of inserting and extracting lithium ions, and a lithium secondary battery equipped with an electrolyte. For example, a non-aqueous electrolyte secondary battery using the negative electrode of the present invention and combining a metal chalcogenide-based positive electrode for a lithium secondary battery that is normally used and an organic electrolyte mainly composed of a carbonate-based solvent has a capacity. Large, low irreversible capacity observed in the initial cycle, excellent cycle characteristics, suppressed electrode expansion after cycling, high battery storage and reliability when left at high temperature, high efficiency discharge characteristics and low temperature It has excellent discharge characteristics.

[Current collector]
As the current collector, for example, a metal cylinder, a metal coil, a metal plate, a metal foil film, a carbon plate, a carbon thin film, a carbon cylinder, or the like is used. Among these, a metal foil film is particularly preferable because it is currently used in industrialized products. The metal thin film may be used in a suitable mesh shape.
The thickness of the metal foil film is not particularly limited, but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less, more preferably 20 μm or less. In the case of a metal foil film thinner than the above range, the strength required as a current collector may be insufficient.

Specific examples of the metal used for the current collector include copper, nickel, stainless steel, iron, titanium, and aluminum. Among these, Preferably copper and nickel are mentioned, More preferably, copper is mentioned. This is because it is easy to bind the negative electrode active material and it is industrially easy to process the shape and size.
[Negative electrode properties]
<Filling density>
The packing density of the negative electrode is not particularly limited, but is usually 0.5 g / cm ³ or more, preferably 0.6 g / cm ³ or more, and usually 2.5 g / cm ³ or less, preferably 2.3 g / cm ³ or less. is there. When the packing density of the negative electrode is below this range, it may be difficult to obtain a high-capacity battery. On the other hand, if it exceeds this range, the amount of pores in the electrode may be reduced, and it may be difficult to obtain preferable battery characteristics.

In addition, as the packing density of the negative electrode, a value obtained by dividing the negative electrode weight excluding the current collector by the negative electrode area and the negative electrode thickness can be used.
<Porosity>
The porosity of the negative electrode is not particularly limited, but is usually 10% or more, preferably 20% or more, and usually 50% or less, preferably 40% or less. When the porosity of the negative electrode is less than this range, there are few pores in the negative electrode, and the electrolyte does not easily penetrate, and it may be difficult to obtain preferable battery characteristics. On the other hand, if it exceeds this range, there may be many pores in the negative electrode and the electrode strength becomes too weak, making it difficult to obtain favorable battery characteristics.

As the porosity of the negative electrode, a percentage of a value obtained by dividing the total pore volume obtained by measuring the pore distribution with a mercury porosimeter of the negative electrode by the apparent volume of the negative electrode active material layer excluding the current collector. Can be used.
[Negative Electrode Structure and Manufacturing Method]
The structure of the negative electrode and the manufacturing method thereof are not particularly limited. For example, the structure of the negative electrode is A: a negative electrode material particle of the present invention, a conductive agent used as necessary, and a binding and thickening effect. Structure B in which an organic substance (hereinafter referred to as “binder”) is applied on a current collector: Particles in which the negative electrode material particles of the present invention are combined with a conductive material, and a binder is applied on the current collector Structure C: Structure in which the negative electrode material particles of the present invention are integrally sintered with the current collector by the sintering agent. Structure D: The negative electrode material particles of the present invention are integrated with the current collector by bonding with the low melting point metal. Structure E: A structure in which the negative electrode material particles of the present invention are integrated with a current collector without a binder component. Below, the structure of the negative electrode of AE and its manufacturing method are demonstrated.
A: Structure in which negative electrode material particles, a conductive agent used as necessary, and a binder are applied on a current collector. This structure is bonded to the negative electrode material particles of the present invention and the negative electrode material A and / or the conductive agent. A negative electrode material particle (also referred to as negative electrode active material) layer containing an agent is formed on a current collector.

<Conductive agent>
The negative electrode active material layer may include a conductive agent. The conductive agent may be any electronic conductive material that does not cause a chemical change at the charge / discharge potential of the negative electrode active material to be used. For example, carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black, conductive fibers such as carbon fiber, vapor grown carbon fiber (VGCF), carbon nanofiber and metal fiber Further, metal powders such as carbon fluoride and copper can be contained alone or as a mixture thereof. Of these conductive agents, acetylene black and VGCF are particularly preferable. These may be used alone or in combination of two or more.

Although the addition amount of a electrically conductive agent is not specifically limited, 1-30 weight% is preferable with respect to a negative electrode active material, and 1-15 weight% is especially preferable.
<Binder>
As the binder, a polymer that is stable against a liquid solvent described later is preferable. For example, polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, polyimide, polyamideimide, polyacrylic acid, polyacrylonitrile, cellulose and other polymer polymers, styrene / butadiene rubber, isoprene rubber, butadiene rubber or ethylene / propylene rubber Heat of rubber-like polymers such as styrene / butadiene / styrene block copolymer, hydrogenated product thereof, styrene / ethylene / butadiene / styrene copolymer, styrene / isoprene / styrene block copolymer and hydrogenated product thereof Soft elastomeric polymers such as plastic elastomeric polymers, syndiotactic 1,2-polybutadiene, ethylene / vinyl acetate copolymers, or propylene / α-olefin (2 to 12 carbon atoms) copolymers, polyfluorinated Vinylidene, Li polytetrafluoroethylene, or fluorinated polymer of the polytetrafluoroethylene-ethylene copolymer, such as an alkali metal ion (especially lithium ion) polymer composition having ion conductivity and the like. These may be used alone or in combination of two or more. A copolymer may also be used.

  Examples of the polymer composition having ion conductivity include polyether polymer compounds such as polyethylene oxide and polypropylene oxide, cross-linked polymers of polyether compounds, polyepoxychlorohydrin, polyphosphazene, and polysiloxane. , A polymer in which a lithium salt or an alkali metal salt mainly composed of lithium is combined with a polymer compound such as polyvinylpyrrolidone, polyvinylidene carbonate, or polyacrylonitrile, or propylene carbonate, ethylene carbonate, γ-butyrolactone, etc. A polymer containing an organic compound having a high dielectric constant or ion-dipole interaction force can be used.

Specifically, resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, polyimide, polyamideimide, polyacrylic acid, or cellulose and its derivatives (for example, carboxymethylcellulose), styrene / butadiene rubber Rubber polymers such as isoprene rubber, butadiene rubber, or ethylene / propylene rubber, fluorine polymers such as polyvinylidene fluoride, polytetrafluoroethylene, or polytetrafluoroethylene / ethylene copolymer, polyethylene oxide, polypropylene oxide Polyether polymer compounds such as polyether polymers and crosslinked polymers of polyether compounds, preferably polyethylene, polypropylene, polyimide, styrene-butadiene rubber, polyvinylidene fluoride, Li polytetrafluoroethylene, or polyethylene oxide and the like, more preferably, polyethylene, styrene-butadiene, polyvinylidene fluoride, or polytetrafluoroethylene. These are currently used industrially and are suitable because they are easy to handle. In the case of a thermosetting resin, a resin precursor may be used.

The negative electrode of this structure is a thin coating of a negative electrode material particle of the present invention, a negative electrode material A and / or a conductive agent, and a slurry in which a binder is dispersed during dispersion on a current collector substrate. Followed by a pressing step of compacting to a predetermined thickness and density. Furthermore, in the case of a thermosetting resin, a step of curing at a predetermined curing temperature in an Ar, N ₂ , and air atmosphere is added, which may be before pressing or after pressing.

  An aqueous solvent or an organic solvent is used as a dispersion medium for preparing a negative electrode active material slurry when a negative electrode active material, a conductive agent and a binder used as necessary are mixed and applied onto a current collector. As the aqueous solvent, water is usually used, and additives such as alcohols such as ethanol and cyclic amides such as N-methylpyrrolidone may be added to water up to about 30% by weight or less. it can.

  As the organic solvent, usually, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and aromatic hydrocarbons such as anisole, toluene and xylene And alcohols such as butanol and cyclohexanol. Among them, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide are preferable.

  A negative electrode active material, a binder, and a conductive agent blended as necessary are mixed with these solvents to prepare a negative electrode active material slurry, and this is applied to the negative electrode current collector substrate so as to have a predetermined thickness. Thus, a negative electrode active material layer is formed. The upper limit of the concentration of the negative electrode active material in the negative electrode active material slurry is usually 60% by weight or less, preferably 50% by weight or less, and the lower limit is usually 10% by weight or more. It is preferably 15% by weight or more. When the concentration of the negative electrode active material exceeds the upper limit, the negative electrode active material in the negative electrode active material slurry tends to aggregate, and when the concentration is lower than the lower limit, the negative electrode active material tends to settle during storage of the negative electrode active material slurry.

The upper limit of the concentration of the binder in the negative electrode active material slurry is usually 30% by weight or less, preferably 20% by weight or less, and the lower limit is usually 1% by weight or more, preferably 2% or more. When the concentration of the binder exceeds the upper limit, the internal resistance of the negative electrode obtained increases, and when the concentration is lower than the lower limit, the binding property of the negative electrode active material layer may be inferior.
B: Structure in which a negative electrode active material is combined with a conductive material, and a binder is applied on a current collector. This structure is bound to a composite of negative electrode material particles and a conductive material of the present invention. An active material layer containing an agent is formed on a current collector and is usually a slurry in which composite particles and a binder are dispersed in water or an organic solvent similar to that in (A) above. Are formed by a thin coating and drying process on a current collector substrate, followed by a pressing process for compacting to a predetermined thickness and density. Also in this case, like A, a conductive agent may be added.

<Conductive substance>
As the conductive substance, conductive oxides and metals such as carbon, graphite, carbon black, copper, aluminum, and tin are used. Examples of the oxide include In2O3, ZnO, SnO2, and SiOx, the carbon includes CVD carbon, and the graphite includes natural graphite, artificial graphite, VGCF, carbon nanofiber, and the like. For example, natural graphite (flaky graphite, spheroidized graphite, etc.), artificial graphite (mesocarbon microbeads, etc.), amorphous carbon obtained by firing pitch or resin, graphite and amorphous carbon are combined Multiphase structural materials. As a method for coating the surface of the negative electrode material particles, heat treatment (pyrolysis), mechanochemical treatment such as a ball mill, or the like is used.

<Composite particle>
The composite particles can be obtained by mixing and compositing the negative electrode material particles of the present invention and a conductive material by a mechanochemical method, a CVD method, a firing method with a carbon precursor, or the like.
As a method for mixing and compounding by the mechanochemical method, for example, an apparatus such as a ball mill, a vibration mill, a planetary ball mill, a mechanofusion (manufactured by Hosokawa Micron), a hybridizer, and Micros (manufactured by Nara Machinery Co., Ltd.) can be used.

Examples of the CVD method include a method in which a hydrocarbon-based gas is used as a raw material, and film-like and / or fibrous pyrolytic carbon (graphite) is formed on the surface of the negative electrode material particles and combined. Note that a catalyst such as Ni may be previously supported on the surface of the negative electrode material particles before the CVD treatment.
As a method of firing with a carbon precursor, a carbon precursor using negative electrode material particles, a conductive material, petroleum pitch, coal pitch, coal tar pitch, resins such as polyvinyl alcohol, phenol resin, and cellulose as raw materials. The method of compounding by mixing and baking by the temperature of about 600-1300 degreeC is mentioned.

As the structure of the composite particles, for example, a structure in which fine particles of negative electrode material particles are embedded in a matrix of a conductive material, a structure in which the surface of the negative electrode material particles is covered with a conductive material, or a negative electrode material Examples include a structure in which a fibrous conductive material is generated on the surface of the particles.
If the content of the conductive material in the composite particles is too large, the amount of the negative electrode active material may decrease and the discharge capacity may be reduced. If the content is too small, the effect of improving the conductivity by combining the conductive materials appears. Since it may be difficult, the content of the negative electrode material particles of the present invention in the composite particles is usually 50% by weight or more, particularly 70% by weight or more, and usually 99% by weight or less, particularly 97% by weight or less. It is preferable.

<Fibrous pyrolytic carbon>
As the fibrous pyrolytic carbon, vapor-phase film-grown growth carbon fiber (VGCF), carbon nanofiber (CNF), carbon nanotube (CNT), or the like can be used. The structure of CNF includes herringbon, platelet, tubular type, etc., and the structure of CNT includes single layer (SWNT), multilayer (MWNT) and the like.

The BET specific surface area of the fibrous pyrolytic carbon is not particularly limited, but is usually 300 m ² / g or less, preferably 200 m ² / g or less, more preferably 100 m ² / g or less. If the value of the BET specific surface area exceeds this upper limit, the fibrous pyrolytic carbon reacts with the electrolytic solution when used as a negative electrode, the initial charge / discharge efficiency decreases, and a preferable battery may not be obtained. Further, the BET specific surface area of the fibrous pyrolytic carbon is usually about 10 m ² / g or more. As a method for measuring the BET specific surface area, the above-described method can be used.

The crystallite plane interval d002 of the fibrous pyrolytic carbon of VCGF or CNF is not particularly limited, but is usually 0.350 nm or less, preferably 0.342 nm or less, and more preferably 0.338 nm or less. If d002 exceeds this upper limit, the fibrous pyrolytic carbon reacts with the electrolyte when used as a negative electrode, the initial charge / discharge efficiency decreases, and a preferred battery may not be obtained. Moreover, d002 of fibrous pyrolytic carbon is 0.3345 nm or more on the measurement principle. As the X-ray diffraction measurement method for obtaining the crystallite plane distance d002, the above-described method can be used.
C: Structure in which the negative electrode active material is integrally sintered with the current collector by the sintering agent. This structure forms the active material layer containing the negative electrode material particles and the sintering agent of the present invention on the current collector. Normally, a negative electrode active material and a sinterable material dispersed and mixed are thinly applied (or molded) and dried onto a current collector substrate, and then pressed to a predetermined thickness and density. It is manufactured by sintering through a heat treatment process.

<Sintering agent>
As the sintering agent, precursors such as oxides, carbides and nitrides, and carbon precursors are used. For example, as an oxide precursor, an organic zirconium compound, an organic titanium compound, or the like is used, and as a carbon precursor, coal pitch, petroleum pitch, or coal tar pitch is heat-treated (oxidized) to adjust a softening point and a volatile content. Product (TGP3500, manufactured by Osaka Chemical Industry Co., Ltd.).

If the amount of the sintering agent used is too large, the amount of the negative electrode active material decreases, and the discharge capacity may be reduced.If the amount is too small, the binding force between the negative electrode active materials or between the negative electrode active material and the current collector decreases, Since the strength of the negative electrode is insufficient and the negative electrode active material may be peeled off, the negative electrode material particles of the present invention are usually 3% by weight or more, preferably 5% by weight or more, usually 50% by weight or less, preferably 30% by weight or less.
D: Structure in which the negative electrode active material is integrated with the current collector by bonding to the low melting point metal This structure forms an active material layer in which the negative electrode material particles of the present invention and the low melting point metal are bonded on the current collector Usually, a negative electrode active material and a low melting point metal dispersed and mixed are thinly coated (or molded) on a current collector substrate, dried, and then pressed to a predetermined thickness / density, Manufactured by a heat treatment process.

<Low melting point metal>
For the low melting point metal, solder, solder or the like is used. For example, examples of the solder include Sn—Pb alloy, low melting point solder added with Bi—In, Ag, Sb, and Cu added solder. If the amount of the low melting point metal used is too large, the amount of the negative electrode active material is decreased, and the discharge capacity may be reduced.If the amount is too small, the binding force between the negative electrode active materials or between the negative electrode active material and the current collector is reduced. Since the strength of the negative electrode is insufficient and the negative electrode active material may be peeled off, the negative electrode material particles of the present invention are usually 5% by weight or more, preferably 10% by weight or more, usually 60% by weight or less, preferably 40% by weight or less.
E: Structure in which the negative electrode active material is integrated with the current collector without the binder component This structure is formed by forming the negative electrode material particles of the present invention on the current collector as the active material layer without the binder component. The negative electrode active material is manufactured by a method in which the negative electrode active material is integrated with the current collector without a binder component by, for example, room temperature impact solidification in which the negative electrode active material collides at high speed under vacuum. More specifically, a method of directly depositing the negative electrode material particles of the present invention on a current collector by an aerosol deposition method can be mentioned.

[3] Non-aqueous electrolyte secondary battery The non-aqueous electrolyte secondary battery of the present invention includes a positive electrode and a negative electrode capable of inserting and extracting lithium ions, and a non-aqueous electrolyte secondary battery including an electrolyte. Is used. There is no particular limitation on the selection of members other than the negative electrode necessary for the battery configuration such as the positive electrode and the electrolyte constituting the nonaqueous electrolyte secondary battery of the present invention. In the following, materials of members other than the negative electrode constituting the nonaqueous electrolyte secondary battery of the present invention will be exemplified, but usable materials are not limited to these specific examples.

[Positive electrode]
The positive electrode is formed by forming a positive electrode active material and an active material layer containing an organic substance (binder) having a binding and thickening effect on a current collector substrate. Usually, the positive electrode active material and the binder are used. Is formed by a thin coating and drying process on a current collector substrate, followed by a pressing process for compacting to a predetermined thickness and density.

<Positive electrode active material>
The positive electrode active material is not particularly limited as long as it has a function capable of inserting and extracting lithium. For example, lithium transition such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, and lithium iron phosphate Metal composite oxide material; Li2MnO3-LiMO2 (M: metal such as Ni, Co, Mn) solid solution material; Transition metal oxide material such as manganese dioxide; Carbonaceous material such as fluorinated graphite can be used. Specifically, LiFeO2
LiCoO2, LiNiO2, LiMn2O4, LiFePO4 and their non-stoichiometric compounds, MnO2, TiS2, FeS2, Nb3S4, Mo3S4, CoS2, V2O5, P2O5, CrO3, V3O3, TeO2, GeO2, and the like can be used. These may be used alone or in combination of two or more.

<Conductive agent>
A positive electrode conductive agent can be used for the positive electrode active material layer. The positive electrode conductive agent may be any electron conductive material that does not cause a chemical change at the charge / discharge potential of the positive electrode active material to be used. For example, graphite such as natural graphite (flaky graphite), artificial graphite, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, carbon fiber, metal fiber, etc. Conductive fibers, metal powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and organic conductive materials such as polyphenylene derivatives Can be included alone or as a mixture thereof. Among these conductive agents, artificial graphite and acetylene black are particularly preferable. These may be used alone or in combination of two or more.

Although the addition amount of a electrically conductive agent is not specifically limited, 1-50 weight% is preferable with respect to a positive electrode active material, and 1-30 weight% is especially preferable. In the case of carbon or graphite, 2 to 15% by weight is particularly preferable.
<Binder>
There is no restriction | limiting in particular as a binder used for formation of a positive electrode active material layer, Any of a thermoplastic resin and a thermosetting resin may be sufficient. For example, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene / butadiene rubber, tetrafluoroethylene / hexafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer (FEP) , Tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / chlorotrifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer (ETFE resin) ), Polychlorotrifluoroethylene (PCTFE), vinylidene fluoride / pentafluoropropylene copolymer, propylene / tetrafluoroethylene copolymer, ethylene / chlorotri Fluoroethylene copolymer (ECTFE), vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer, vinylidene fluoride / perfluoromethyl vinyl ether / tetrafluoroethylene copolymer, ethylene / acrylic acid copolymer or (Na +) ion cross-linked body, ethylene / methacrylic acid copolymer or (Na +) ion cross-linked body of the material, ethylene / methyl acrylate copolymer or (Na +) ion cross-linked body of the material, ethylene / methyl methacrylate co-polymer Examples thereof include polymers or (Na +) ion-crosslinked products of the above materials, and these materials can be used alone or as a mixture. Among these materials, more preferable materials are polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).

<Other additives>
In addition to the conductive agent described above, the positive electrode active material layer may further contain a filler, a dispersant, an ionic conductor, a pressure enhancer, and other various additives. Any filler can be used as long as it is a fibrous material that does not cause a chemical change in the constructed battery. Usually, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used. Although the addition amount of a filler is not specifically limited, 0-30 weight% is preferable as content in an active material layer.

<Solvent>
In preparing the positive electrode active material slurry, an aqueous solvent or an organic solvent is used as a dispersion medium. As the aqueous solvent, water is usually used, and additives such as alcohols such as ethanol and cyclic amides such as N-methylpyrrolidone may be added to water up to about 30% by weight or less. it can.

  As the organic solvent, usually, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and aromatic hydrocarbons such as anisole, toluene and xylene And alcohols such as butanol and cyclohexanol. Among them, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide are preferable.

A positive electrode active material, a binder as a binder, an organic substance having a thickening effect, a positive electrode conductive agent blended as necessary, and other fillers are mixed in these solvents to prepare a positive electrode active material slurry, The positive electrode active material layer is formed by applying this to the positive electrode current collector substrate so as to have a predetermined thickness.
The upper limit of the concentration of the positive electrode active material in the positive electrode active material slurry is usually 70% by weight or less, preferably 55% by weight or less, and the lower limit is usually 30% by weight or more, preferably 40% by weight or more. When the concentration of the positive electrode active material exceeds the upper limit, the positive electrode active material in the positive electrode active material slurry tends to aggregate, and when the concentration is lower than the lower limit, the positive electrode active material may easily settle during storage of the positive electrode active material slurry.

Further, the upper limit of the concentration of the binder in the positive electrode active material slurry is usually 30% by weight or less, preferably 10% by weight or less, and the lower limit is usually 0.1% by weight or more, preferably 0.5% or more. . When the concentration of the binder exceeds this upper limit, the internal resistance of the positive electrode obtained increases, and when it falls below the lower limit, the binding property of the positive electrode active material layer may be inferior.
<Current collector>
As the positive electrode current collector, for example, it is preferable to use a valve metal or an alloy thereof that forms a passive film on the surface by anodic oxidation in an electrolytic solution. Examples of the valve metal include metals belonging to Groups 4, 5, and 13 of the periodic table and alloys thereof. Specifically, Al, Ti, Zr, Hf, Nb, Ta and alloys containing these metals can be exemplified, and Al, Ti, Ta and alloys containing these metals can be preferably used. . In particular, Al and its alloys are desirable because of their light weight and high energy density. The thickness of the positive electrode current collector is not particularly limited, but is usually about 1 to 50 μm.

[Electrolytes]
Any electrolyte such as an electrolytic solution or a solid electrolyte can be used as the electrolyte. Here, the electrolyte refers to all ionic conductors, and both the electrolytic solution and the solid electrolyte are included in the electrolyte.
As the electrolytic solution, for example, a solution obtained by dissolving a solute in a non-aqueous solvent can be used. As the solute, an alkali metal salt, a quaternary ammonium salt, or the like can be used. Specifically, LiClO ₄ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) _{3 and the} like are preferably used. One kind of these solutes may be selected and used, or two or more kinds may be mixed and used.

The content of these solutes in the electrolytic solution is preferably 0.2 mol / L or more, particularly 0.5 mol / L or more, and 2 mol / L or less, particularly 1.5 mol / L or less.
Examples of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate and ethynyl ethylene carbonate, cyclic ester compounds such as γ-butyrolactone; chain ethers such as 1,2-dimethoxyethane; crown Cyclic ethers such as ether, 2-methyltetrahydrofuran, 1,2-dimethyltetrahydrofuran, 1,3-dioxolane, and tetrahydrofuran; chain carbonates such as diethyl carbonate, ethylmethyl carbonate, and dimethyl carbonate can be used. Among these, a nonaqueous solvent containing a cyclic carbonate and a chain carbonate is preferable. One type of these solvents may be selected and used, or two or more types may be mixed and used.

The nonaqueous electrolytic solution according to the present invention may contain various auxiliary agents such as a cyclic carbonate having an unsaturated bond in the molecule, a conventionally known overcharge inhibitor, a deoxidizer, and a dehydrator.
Examples of the cyclic carbonate having an unsaturated bond in the molecule include vinylene carbonate compounds, vinyl ethylene carbonate compounds, methylene ethylene carbonate compounds, and the like.

Examples of the vinylene carbonate compounds include vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, 4,5-diethyl vinylene carbonate, fluoro vinylene carbonate, trifluoromethyl vinylene carbonate, and the like.
Examples of the vinyl ethylene carbonate compound include vinyl ethylene carbonate, 4-methyl-4-vinyl ethylene carbonate, 4-ethyl-4-vinyl ethylene carbonate, 4-n-propyl-4-vinyl ethylene carbonate, 5-methyl- Examples include 4-vinylethylene carbonate, 4,4-divinylethylene carbonate, 4,5-divinylethylene carbonate, and the like.

Examples of the methylene ethylene carbonate compound include methylene ethylene carbonate, 4,4-dimethyl-5-methylene ethylene carbonate, 4,4-diethyl-5-methylene ethylene carbonate, and the like.
Of these, vinylene carbonate and vinyl ethylene carbonate are preferable, and vinylene carbonate is particularly preferable.

These may be used individually by 1 type, or may use 2 or more types together.
When the non-aqueous electrolyte contains a cyclic carbonate compound having an unsaturated bond in the molecule, the proportion in the non-aqueous electrolyte is usually 0.01% by weight or more, preferably 0.1% by weight or more, particularly Preferably it is 0.3% by weight or more, most preferably 0.5% by weight or more, usually 8% by weight or less, preferably 4% by weight or less, particularly preferably 3% by weight or less.

By including in the electrolyte a cyclic carbonate having an unsaturated bond in the molecule, the cycle characteristics of the battery can be improved. Although the reason is not clear, it is presumed that a stable protective film can be formed on the surface of the negative electrode. However, when the content is small, this property is not sufficiently improved. However, if the content is too large, the gas generation amount tends to increase during high-temperature storage, so the content in the electrolyte is preferably in the above range.

Examples of the overcharge inhibitor include aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; -Partially fluorinated products of the aromatic compounds such as fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; fluorine-containing compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole and 2,6-difluoroanisole Anisole compounds and the like can be mentioned. These may be used alone or in combination of two or more.

The ratio of the overcharge inhibitor in the non-aqueous electrolyte is usually 0.1 to 5% by weight. By containing an overcharge preventing agent, rupture / ignition of the battery can be suppressed during overcharge or the like.
Examples of other auxiliaries include carbonate compounds such as fluoroethylene carbonate, trifluoropropylene carbonate, phenylethylene carbonate, erythritan carbonate, spirobis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, Carboxylic anhydrides such as maleic anhydride, anhydrous sheet laconic acid, anhydrous glutaconic acid, itaconic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; ethylene monkey Phyto, 1,3-propane sultone, 1,4-butane sultone, methyl methanesulfonate, busulfan, sulfolane, sulfolene, dimethyl sulfone and tetramethylthiuram mono Sulfur-containing compounds such as rufide, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1 , 3-dimethyl-2-imidazolidinone and nitrogen-containing compounds such as N-methylsuccinimide; hydrocarbon compounds such as heptane, octane and cycloheptane; fluorobenzene, difluorobenzene, hexafluorobenzene, benzotrifluoride, etc. And fluorine-containing aromatic compounds. These may be used alone or in combination of two or more.

The ratio of these auxiliaries in the nonaqueous electrolytic solution is usually 0.1 to 5% by weight. By containing these auxiliaries, capacity maintenance characteristics and cycle characteristics after high-temperature storage can be improved.
The non-aqueous electrolytic solution may contain an organic polymer compound in the electrolytic solution, and may be a gel, rubber, or solid sheet solid electrolyte. In this case, specific examples of the organic polymer compound include polyether polymer compounds such as polyethylene oxide and polypropylene oxide; crosslinked polymers of polyether polymer compounds; vinyl alcohol polymers such as polyvinyl alcohol and polyvinyl butyral. Compound; Insolubilized product of vinyl alcohol polymer compound; Polyepoxy chlorohydrin; Polyphosphazene; Polysiloxane; Vinyl polymer compound such as polyvinyl pyrrolidone, polyvinylidene carbonate, polyacrylonitrile; Poly (ω-methoxyoligooxyethylene Methacrylate), poly (ω-methoxyoligooxyethylene methacrylate-co-methyl methacrylate), and other polymer copolymers.

[Other components]
In addition to the electrolyte, the negative electrode, and the positive electrode, an outer can, a separator, a gasket, a sealing plate, a cell case, and the like can also be used as the negative electrode for the nonaqueous electrolyte secondary battery.
The material and shape of the separator are not particularly limited. The separator is separated so that the positive electrode and the negative electrode are not in physical contact, and preferably has high ion permeability and low electrical resistance. The separator is preferably selected from materials that are stable with respect to the electrolyte and excellent in liquid retention. Specific examples include porous sheets or nonwoven fabrics made from polyolefins such as polyethylene and polypropylene.

[Shape of non-aqueous electrolyte secondary battery]
The shape of the nonaqueous electrolyte secondary battery of the present invention is not particularly limited. For example, 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 pellet electrode and a separator It can be made into the coin type etc. which laminated | stacked.

[Method for producing non-aqueous electrolyte secondary battery]
The method for producing the nonaqueous electrolyte secondary battery of the present invention having at least an electrolyte, a negative electrode, and a positive electrode is not particularly limited and can be appropriately selected from commonly employed methods.
An example of the method for producing the nonaqueous electrolyte secondary battery of the present invention is as follows: a negative electrode is placed on an outer can, an electrolytic solution and a separator are provided thereon, and a positive electrode is placed so as to face the negative electrode; A method of assembling the battery by caulking with a sealing plate is mentioned.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples, unless the summary is exceeded.
The measuring methods for physical properties in the examples are as follows.
・ Average particle size (D50)
The volume-based average particle size (D50) is obtained by dispersing 10 mg of negative electrode material particles using ion-exchanged water as a dispersion medium, and then using a laser diffraction particle size distribution meter (for example, “LA-920” manufactured by Horiba, Ltd.) The volume-based average particle diameter (D50) was measured.

-Half-value width by X-ray diffraction The half-value width of the Si (111) surface of the negative electrode material particles in the X-ray diffraction measurement was set on the irradiated surface of the negative electrode material particles of the present invention, and an X-ray diffraction apparatus ("X ' PertPro
MPD "). Measurement conditions were such that negative electrode material particles were set in a measurement cell, and measurement was performed in a range of 2θ = 5 to 70 degrees with a concentrated optical system. Background correction was performed by the curve fitting method.

After background correction, curve fitting is performed on the peak corresponding to the Si (111) plane where 2θ is 28.4 degrees, the half width of the peak is obtained, and the value after correction by the external standard is used as the negative electrode material. The half-value width of the particle was used.
-Crystallite size The crystallite size was calculated from the half-value width obtained above using the following Scherrer equation. Here, the constant K is 0.9.
Scherrer's formula
D = (Kλ) / (βcosθ)
λ is the measured X-ray wavelength (Å)
β is the full width at half maximum (rad)
θ is the Bragg angle (rad) of the diffraction line
-Composition analysis of negative electrode material particles The composition of the negative electrode material particles was obtained by dissolving the negative electrode material particles in an alkali and then measuring the acid content with ICP-AES to measure the Si content. Oxygen content is oxygen nitrogen analyzer, ON analyzer (impulse furnace heating extraction under inert gas atmosphere-IR, TCD detection), LECO oxygen nitrogen analyzer TC600), carbon content is carbon sulfur analyzer CS analysis Measured using a meter (high-frequency furnace combustion-IR detection method, carbon sulfur analyzer CS600 manufactured by LECO), respectively, measured the weight percentage (mass%) contained in the negative electrode material particles, and corrected the value to atomic% And Si
The x and y compositions were determined in terms of the atomic concentration ratio of Z and M, where 1 is 1.

[Example 1]
The Si raw material was introduced into a graphite crucible, and melted and vaporized at a vacuum degree of 3 × 10 ⁻⁵ torr and 1850 ° C. by a high frequency induction heating apparatus (SK Medical Electronics), and the evaporated Si atoms were rapidly cooled and condensed on the opposing cooling copper plate. After the copper plate was taken out, the obtained condensate was easily peeled off from the copper plate to obtain flakes / powder and about 1.2 g of flakes. The obtained flakes / powder were pulverized in an agate mortar and then classified with a planetary ball mill (Fritsch P-7 type) at 500 rpm for 3 minutes and classified with a sieve having an aperture of 38 μm to obtain negative electrode material particles.

A transmission electron microscope (TEM) photograph of the obtained negative electrode material particles is shown in FIGS. As shown in the figure, a lattice image corresponding to the crystal structure was not observed, and the structure was confirmed to be amorphous.
The volume-based average particle diameter (D50) of the negative electrode material particles was measured by a particle size distribution meter (“LA-920” manufactured by Horiba Seisakusho) according to the method described above, and it was 1.6 μm.

When the composition of the negative electrode material particles was analyzed by an element analyzer according to the above method, element C was 8.6 atomic% and element O was 11.8 atomic% in the powder. In terms of atomic concentration ratio, this was Si: C: O = 1.00: 0.11: 0.15.
It was 9.2 degree | times when quantitative determination of the half value width by the X ray diffraction of the negative electrode material particle was performed according to the said method. The crystallite size was 0.9 nm, and it was confirmed that the crystallite size was in an amorphous state without long-range order.

<Method for producing negative electrode for lithium secondary battery>
0.7 g of negative electrode material particles produced by the above method, 0.1 g of acetylene black (HS-100) as a conductive material, 1.08 g of polyamic acid NMP solution as a polyimide precursor (solid content concentration 18.6 wt%), and About 1.5 g of NMP was added and mixed. The mixture thus obtained was applied on a copper foil having a thickness of 10 μm and then pre-dried at 90 ° C. for 50 minutes. The electrode was pressed with a roll press and then heat treated under a nitrogen stream at 350 ° C. for 1 hour to cure the polyamic acid to polyimide. Further, it was punched out to a diameter of 12.5 mmφ to obtain a negative electrode for evaluation.

<Method for producing lithium secondary battery>
The obtained negative electrode was transferred to a glove box under an argon atmosphere, and 1 mol / L- using a mixed solution of fluoroethylene carbonate (FEC) / dimethyl carbonate (DMC) = 8/2 (weight ratio) as a solvent as an electrolytic solution. A coin battery (lithium secondary battery) was prepared using a LiPF6 electrolyte, a polyethylene separator as a separator, and a lithium metal counter electrode as a counter electrode.

<Evaluation of discharge capacity>
The charge / discharge conditions in the first cycle were charged to 5 mV with respect to the lithium counter electrode at a current density of 0.33 mA / cm ² and further charged to a current value of 0.07 mA at a constant voltage of 5 mV. Thereafter, lithium was doped to the lithium counter electrode to 1.5 V at a current density of 0.33 mA / cm ² . The charging conditions after the second cycle are as follows: charge to 5 mV with respect to the lithium counter electrode at a current density of 1.3 mA / cm ² , and further charge until the current value becomes 0.26 mA at a constant voltage of 5 mV. After lithium was doped, the battery was discharged to 1.5 V with respect to the lithium counter electrode at a current density of 1.3 mA / cm ² . For the discharge capacity, the value at the third cycle is adopted. When the discharge capacity per weight is used, the active material weight is obtained by subtracting the weight of the copper foil punched out in the same area from the negative electrode weight, and the cycle maintenance rate, charge The discharge efficiency was calculated according to the following.

<Evaluation of cycle characteristics (A)>
This charge / discharge cycle was repeated 40 times according to the above-described method for measuring discharge capacity, and the cycle maintenance ratio (A) was calculated as follows.
Cycle maintenance rate (A) (%)
= {Discharge capacity after 40 cycles (mAh / g) / 3 average discharge capacity after 3 cycles (mAh / g)} × 100
<Evaluation of charge / discharge efficiency during 40 cycles>
According to the measurement method of the cycle characteristic (A) described above, this charge / discharge cycle was repeated 40 times, and the charge / discharge efficiency at 40 cycles was calculated.

Charging / discharging efficiency at 40 cycles (%)
= {Discharge capacity at 40 times (mAh / g) / Charge capacity at 40 times (mAh / g)} × 100
<Measurement of electrode expansion coefficient after cycle>
After measurement of the above cycle characteristics (A) (after 20 cycles), the discharged coin cell is disassembled so as not to be short-circuited in the argon glove box, the electrode is taken out, washed with dehydrated dimethyl ether solvent, dried, The thickness (excluding copper foil) of the electrode at the time of discharge after cycling was measured by SEM observation. Based on the following formula, the electrode expansion coefficient after the cycle was obtained based on the thickness of the electrode (excluding the copper foil) before battery preparation.

Electrode expansion rate after cycle (times) = (electrode thickness after cycle / electrode thickness before charge / discharge)
The physical properties of the negative electrode powder used here are shown in Table 1, and the battery evaluation results are shown in Tables 2 and 3.
[Example 2]
Except for changing the degree of vacuum to 3 × 10 ⁻³ torr, the same procedure as in Example 1 was performed to obtain 2.4 g of flakes / powder.

As in Example 1, when the particle size was measured after sieving and pulverization, the average particle size (D50) was 2.4 μm.
The composition of the negative electrode material particles was analyzed in the same manner as in Example 1. As a result, element C was 12.6 atomic% and element O was 7.8 atomic% in the powder. In terms of atomic concentration ratio, Si: C: O = 1.00: 0.16: 0.10.

It was 8.5 degree | times when the half value width by the X-ray diffraction of the negative electrode material particle was quantified according to the said method. The crystallite size was 1.0 nm, and it was confirmed that the crystallite size was in an amorphous state without long-range order.
Using this negative electrode material particle, the negative electrode and coin battery were prepared and evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 3 together with the physical properties.

[Example 3]
Except for increasing the size of the graphite crucible, the same procedure as in Example 1 was performed to obtain 1.3 g of flakes / powder.
As in Example 1, when the particle size was measured after sieving and pulverization, the average particle size (D50) was 1.2 μm.

When the composition analysis of the negative electrode material particles was performed in the same manner as in Example 1, the element C was 8.8 atomic% in the powder.
Element O was 4.3 atomic%. In terms of atomic concentration ratio, Si: C: O = 1.00: 0.10: 0.05.
It was 6.9 degree | times when the half value width by the X-ray diffraction of the negative electrode material particle was quantified according to the said method. Further, the crystallite size was 1.2 nm, and it was confirmed that the crystallite size was in an amorphous state without long-range order. Preparation and evaluation were performed, and the results are shown in Tables 1 and 3 together with physical property values.

[Example 4]
Except for changing the melting and vaporizing temperature of Si to 1950 ° C., the same procedure as in Example 1 was performed to obtain 2.5 g of flakes / powder.
The obtained flakes / powder were pulverized in an agate mortar and then pulverized with a planetary ball mill for 30 minutes at 500 rpm and classified with a sieve having an aperture of 38 μm to obtain negative electrode material particles.

As in Example 1, when the average particle size (D50) was measured after sieving and pulverization, the average particle size (D50) was 0.6 μm.
When the composition analysis of the negative electrode material particles was performed in the same manner as in Example 1, element C was 13.6 atomic% and element O was 3.0 atomic% in the powder. In terms of atomic concentration ratio, Si: C: O = 1.00: 0.16: 0.04.

It was 8.2 degree | times when the half value width by the X ray diffraction of the negative electrode material particle was quantified according to the said method. The crystallite size was 1.0 nm, and it was confirmed that the crystallite size was in an amorphous state without long-range order. 0.1 g of graphite and 0.1 g of SiO were added to 0.5 g of the negative electrode material particles. The negative electrode and the coin battery were produced and evaluated in the same manner as in Example 1 except that the results were shown in Tables 1 and 3 together with the physical properties.
[Example 5]
The same procedure as in Example 1 was conducted except that a small amount of CO ₂ gas was introduced into the vacuum chamber to obtain 0.2 g of flakes / powder.

When the composition analysis of the negative electrode material particles was performed in the same manner as in Example 1, the element C was 8.8 atomic% in the powder.
The element O was 22.1 atomic%. In terms of atomic concentration ratio, Si: C: O = 1.00: 0.13: 0.32.
It was 9.9 degree | times when the half value width by the X-ray diffraction of the negative electrode material particle was quantified according to the said method. The crystallite size was 0.8 nm, and it was confirmed that the crystallite size was in an amorphous state without long-range order.

[Comparative Example 1]
With respect to the commercially available Si particles, the average particle diameter (D50) of the Si powder was measured by a particle size distribution analyzer in the same manner as in Example 1. As a result, it was 1.8 μm.
When the composition analysis of the Si powder was performed in the same manner as in Example 1, the elements C and N were not contained in the powder and were below the detection limit.

It was 0.1 degree | times when the half value width by the X ray diffraction of the negative electrode material particle was quantified according to the said method. Further, the crystallite size was 100 nm or more, and it was confirmed that the crystallite size has long-range order, that is, high crystallinity.
Using this Si powder, a negative electrode and a coin battery were produced and evaluated in the same manner as in Example 1. Moreover, SEM observation after a charge / discharge cycle was implemented similarly to Example 1, and the electrode expansion coefficient after a cycle was calculated | required. The results are shown in Table 1, Table 2 and Table 3 together with physical property values.

[Comparative Example 2]
It implemented on the conditions similar to Example 2, and obtained 1.0-g flakes and powdery material.
The obtained flakes / powder were pulverized in an agate mortar and then pulverized with a planetary ball mill, and classified with a sieve having an aperture of 38 μm to obtain negative electrode material particles.
When the particle size was measured as in Example 1, the average particle size (D50) was 22 μm.

When the composition analysis of the negative electrode material particles was performed in the same manner as in Example 1, element C was 13.6 atomic% and element O was 3.0 atomic% in the powder. In terms of atomic concentration ratio, Si: C: O = 1.00: 0.16: 0.04.
It was 8.2 degree | times when the half value width by the X ray diffraction of the negative electrode material particle was quantified according to the said method. The crystallite size was 1.0 nm, and it was confirmed that the crystallite size was in an amorphous state without long-range order. Using this Si powder, production of a negative electrode and a coin battery was performed in the same manner as in Example 1. The results are shown in Tables 1 and 3 together with the physical property values.

From Tables 1 to 3, the following can be understood.
The negative electrode material particles of Comparative Example 1 were Si powder, but the composition of C and O was outside the specified range. As a result, good cycle characteristics were not obtained, and the electrode expansion coefficient after cycling was large.
The negative electrode material particles of Comparative Example 2 are SiZxMy powder, and the composition thereof is Si: C: O = 1.00: 0.16: 0.10, which is within the specified range of the present invention, but the particle size is 22 μm. As a result, good cycle characteristics could not be obtained.

  On the other hand, as shown in Table 1, the negative electrode material particles of the present invention of Examples 1 to 5 are represented by a compound SiZxMy composed of Si, an element Z, and an element M, and the element Z includes C and / or An element composed of N and M is an element composed of O and have an amorphous structure, all satisfying the specified range of the present invention. And as shown in Table 2, the particle | grains which have the element which consists of C and / or N in Si, and the element which consists of M in O has Si-C bond, Si-O bond, Si-Si bond It was found that the expansion of the electrode after charge / discharge was suppressed because of the stronger bond.

  Further, as shown in Examples 1 to 4 and Comparative Examples 1 to 3, Comparative Example 1 in which the negative electrode material particles of Examples 1 to 4 having an amorphous structure represented by the compound SiZxMy and crystals are used. When comparing the Si particles, the capacity of the negative electrode material particles of Examples 1 to 4 was maintained sufficiently after 40 cycles, but in the case of crystalline Si particles, the cycle retention rate was 3%, and the capacity deterioration was severe. I understood it. When the negative electrode material particles as in Examples 1 to 4 are used, a high-performance battery having a high discharge capacity, high charge and discharge efficiency in the initial stage and in the cycle, excellent cycle characteristics, and suppressed electrode expansion after the cycle. It turns out that it is obtained.

  By using the carbon material of the present invention as a carbon material for a non-aqueous secondary battery, a negative electrode material for a non-aqueous secondary battery having a high capacity and good charge / discharge load characteristics can be provided. Moreover, according to the manufacturing method of the said material, since there are few processes, it can manufacture stably and efficiently and cheaply.

Claims (8)

A negative electrode material for a non-aqueous electrolyte secondary battery containing a compound SiZxMy composed of Si, element Z and element M satisfying the following conditions (1) to ( 7 ).
(1) The element Z is at least one of C and N.
(2) The range of x is 0.01 ≦ x ≦ 0.18.
(3) Element M is one or more elements selected from elements other than Si and element Z.
(4) The range of y is 0.01 ≦ y ≦ 0.35.
(5) The average particle diameter (D50) is 50 nm or more and 20 μm or less.
(6) An amorphous structure.
(7) The half width of the Si (111) surface measured by X-ray diffraction is 6 degrees or more. 2. The negative electrode material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the crystallite size of the fine particles represented by the compound SiZxMy is in the range of 0.1 nm to 5 nm. Negative electrode material for non-aqueous electrolyte secondary battery according to claim 1 or 2 Raman shift measured by Raman spectroscopy, characterized in that in the range of ^{250cm -1 ~500cm} -1. In manufacturing a negative electrode material for a non-aqueous electrolyte secondary battery containing a compound SiZxMy composed of Si, element Z and element M satisfying the following conditions (1) to (5) , the Si raw material is melted and then evaporated and vaporized. In the negative electrode material for a non-aqueous electrolyte secondary battery , the raw material to be element M is introduced when quenching and condensing in the opposing cooling section , and the rapid condensing speed is 500 ° C./second or more . Manufacturing method .
(1) The element Z is at least one of C and N.
(2) The range of x is 0.01 ≦ x ≦ 0.18.
(3) Element M is one or more elements selected from elements other than Si and element Z.
(4) The range of y is 0.01 ≦ y ≦ 0.35.
(5) The average particle diameter (D50) is 50 nm or more and 20 μm or less. The method for producing a negative electrode material for a non-aqueous electrolyte secondary battery according to claim 4 , wherein the raw material to be the element M is CO and / or CO2 gas. A negative electrode material for a non-aqueous electrolyte secondary battery obtained by the production method according to claim 4 or 5 . A current collector, provided with a negative electrode material formed on the current collector, and wherein the negative electrode material is contains a negative electrode material according to any one of claims 1 to 3 6 A negative electrode for a non-aqueous secondary battery. 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 7 .