JP7052495B2 - Spherical hydrogen polysilsesquioxane fine particles and spherical silicon oxide fine particles, and a method for producing these. - Google Patents

Description

The present invention relates to spherical hydrogen polysilsesquioxane fine particles and spherical silicon oxide fine particles, and a method for producing these. Furthermore, the present invention relates to a negative electrode active material for a secondary battery, a negative electrode for a secondary battery, and a secondary battery using the spherical silicon oxide fine particles.

Various silicon-containing polymers such as polysilsesquioxane and various silicon oxides and silicon oxide structures have structures at the molecular level, nanometer scale, or micrometer scale, etc. by appropriately adjusting synthetic conditions, production conditions, and the like. Since it can control and realize various functionality, it is applied to various fields such as electronic equipment field, optical equipment field, and electricity storage technology field including batteries.

For example, Patent Document 1 describes a negative electrode active material for a lithium ion secondary battery containing a silicon oxide having a predetermined peak intensity ratio in an infrared spectroscopic spectrum. This silicon oxide is obtained by heat-treating a hydrogen polysilsesquioxane polymer under predetermined conditions, and when used as a negative electrode active material for a secondary battery, it has an excellent charge / discharge capacity in a secondary battery. It has been shown that the capacity retention rate can be demonstrated.

Further, Patent Document 2 describes an amorphous silicon oxide exhibiting a predetermined binding energy, a predetermined silicon peak, etc. in an X-ray photoelectron spectrum, and discloses a negative electrode active material containing the amorphous silicon oxide and a method for producing the same. ing. This amorphous silicon oxide is represented by SiO _X (0 <x <2). Specifically, it is a hydrogen policy obtained by subjecting a silane compound to a sol / gel reaction under an acid catalyst. It is a calcined product of lucesquioxane. Patent Document 2 suggests that excellent charge / discharge characteristics are exhibited by using such a negative electrode active material.

Further, Patent Document 3 describes the intensity of the peak A1 derived from the silanol group in the predetermined wavenumber range and the intensity of the peak A2 derived from the siloxane bond in the predetermined wavenumber range in the spectrum measured by the Fourier transform infrared spectroscope. A negative value active material for a lithium ion secondary battery represented by the general formula SiO _x (0 <X <2) is disclosed in which the value A1 / A2 of the ratio to A1 / A2 is 0.1 or less. Specifically, the negative electrode active material for a lithium ion secondary battery is manufactured as follows. First, Si powder and SiO ₂ powder are mixed, mixed, granulated and dried to obtain mixed granulation. Next, using the mixed granulation as a raw material, SiO _x (0 <X <2) is precipitated on the precipitation substrate by a predetermined device, and the precipitated SiO _x is pulverized to obtain the powder. The powder is heated and held under a predetermined atmosphere and subjected to decompression treatment to obtain a final product. The reason for adopting the SiO _x (0 <X <2) powder in which the ratio A1 / A2 of the intensity of the peak A1 to the intensity of the peak A2 is 0.1 or less in Patent Document 3 is the Si—H bond. Is to generate a silanol group and cause deterioration of the initial efficiency. Therefore, it can be said that a substance having a relatively small peak intensity derived from the silanol group is adopted in the Fourier transformed infrared spectroscopic spectrum.

Further, Patent Document 4 discloses a method for preparing microspheres of polysilsesquioxane, which is considered to be environmentally friendly. This method includes a step of hydrolyzing a trifunctional silane compound represented by R ¹ Si (OR ² ) ₃ with an acidic solution in a predetermined pH range, adjusting the pH to the alkaline side, and polycondensing the compound. Is considered. According to the disclosure of Patent Document 4, it is considered that a silane compound in which R ¹ is hydrogen is also formally included. That is, when R ¹ is hydrogen, the polysilsesquioxane synthesized from the silane compound is logically hydrogen polysilsesquioxane, but in reality, the silane compound in which R ¹ is hydrogen is used. It is considered that no example of synthesizing hydrogen polysilence sesquioxane using hydrogen polysilsesquioxane has been described.

Further, Patent Document 5 describes a phase separation inducer such as polyethylene oxide and polyvinylpyrrolidone and water addition of a silicon compound when synthesizing hydrogen polysilsesquioxane by hydrolysis and polycondensation of a silicon compound such as trimethoxysilane. It is described that a structure called a macroporous monolith having a hierarchical porous structure of mesopores and macropores was produced by adding alcohol or the like as a material for suppressing decomposition and polycondensation. According to the disclosure of Patent Document 5, the macroporous monolith is composed of macropores continuously formed by a skeleton composed of hydride silica and mesopores formed on the surface of the skeleton. Specifically, when looking at the SEM photograph, it is considered that the silica skeleton is a porous body formed in a network shape. In Patent Document 5, a separation column for chromatography, an enzyme carrier, a catalyst carrier, and the like are mentioned as applications of the macroporous monolith.

Further, Non-Patent Document 1 describes the synthesis of nanocrystalline silicon dispersed in a mesoporous silica / suboxide matrix via vesicle-like silsesquioxane, and the possibility of its electrochemical application. It is stated that it was investigated. In Non-Patent Document 1, triethoxysilane is hydrolyzed at room temperature in the presence of Pluronic® P-123 (PEO / PPO / PEO triblock copolymer) to form a thin partition of hydrogen silsesquioxane gel. The resulting nanoscale vesicles are formed and the vesicles are calcined to obtain the above matrix structure.

International Publication No. 2017/010365 Pamphlet Japanese Unexamined Patent Publication No. 2008-1718113 Japanese Unexamined Patent Publication No. 2011-108635 Chinese Patent Application Publication No. CN1080440 Japanese Unexamined Patent Publication No. 2014-148456

New Journal of Chemistry (2015), 39 (1), p621-630

The present inventors have obtained two types of polysilsesquioxane containing hydrogen polysilsesquioxane disclosed in Patent Document 1 and silicon oxides obtained by heat-treating the various polysilsesquioxane. It has been developed for use as a negative electrode active material for next batteries. While developing such various polysilsesquioxane materials, polysilsesquioxane obtained from a trifunctional organosilane compound having an organic functional group in the side chain can be hydrolyzed by a conventional method. Spherical polysilsesquioxane can be easily obtained through a polycondensation reaction, whereas hydrogen polysilsesquioxane obtained from a trifunctional silane compound having a hydrogen atom in a side chain is indefinite. It was found that it is difficult to obtain a spherical hydrogen polysilsesquioxane by a conventional method because only a form in which the fine particles of the above are aggregated can be obtained.

That is, an object of the present invention is to provide substantially spherical hydrogen polysilsesquioxane fine particles, substantially spherical silicon oxide fine particles, and a method for producing these.

In addition, in any of the above-mentioned prior art documents, an example of synthesizing spherical hydrogen polysilsesquioxane fine particles is not disclosed, and a specific method and a specific method capable of synthesizing spherical hydrogen polysilsesquioxane fine particles and No means have been suggested.

In particular, Patent Document 4 discloses a method for preparing microspheres of polysilsesquioxane. As described above, in the silane compound represented by R ¹ Si (OR ² ) ₃ as a raw material, the case where R ¹ is hydrogen is formally included, and if the silane compound is used as a raw material, hydrogen polysilsesquioki is included. Although sun can be obtained, it is considered that no example of synthesizing hydrogen polysilsesquioxane using a silane compound in which ^R1 is hydrogen is actually described. In the examples of Patent Document 4, only examples using methyltrimethoxysilane and temeramethoxysilane (tetramethyl orthosilicate) as silane compounds are described, and the synthesis methods thereof are also very general hydrolysis and polycondensation. It is considered to be based on the reaction. Patent Document 4 does not describe a specific solution for obtaining spherical hydrogen polysilsesquioxane, and does not suggest any phase separation of a solution system as adopted in the present invention.

Further, Patent Document 5 employs a configuration in which an alcohol or the like is added as a phase separation inducer such as polyethylene oxide or polyvinylpyrrolidone or a material for suppressing hydrolysis and polycondensation of a silicon compound, but the structure is produced. Is a macroporous monolith structure having a network structure with a silica skeleton, and is not intended for the synthesis of spherical hydrogen polysilcesquioxane as in the present invention.

Furthermore, in Non-Patent Document 1, triethoxysilane is hydrolyzed at room temperature in the presence of Pluronic® P-123 (PEO / PPO / PEO triblock copolymer) to form a structure of hydrogen silsesquioxane gel. However, the structure is a vesicle (follicle-like structure) and is not in the form of spherical hydrogen polysilsesquioxane fine particles as in the present invention.

In order to solve the above problems, the following are provided according to some aspects of the present invention.
[1] Hydrogen polysilsesquioxane fine particles having a volume-based cumulative 50% particle diameter D50 of less than 1 mm and a substantially spherical shape in the particle size distribution.

[2] The hydrogen polysilsesquioxane fine particles according to [1], wherein the volume-based cumulative 50% particle diameter D50 is 80 μm or less.
[3] The hydrogen polysilsesquioxane fine particles according to [1] or [2], wherein the volume-based cumulative 50% particle diameter D50 is a predetermined value in the range of 100 nm to 50 μm.
[4] The hydrogen polysilsesquioxane fine particles according to any one of [1] to [3], wherein the volume-based cumulative 50% particle diameter D50 is a predetermined value in the range of 500 nm to 10 μm.

式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４はそれぞれ独立に、水素、炭素数１～４５の置換又は非置換のアルキル、置換又は非置換のアリール、及び置換又は非置換のアリールアルキルからなる群から選択される基であり、炭素数の１～４５のアルキルにおいて、任意の水素はハロゲンで置き換えられてもよく、任意の－ＣＨ_２－は、－Ｏ－、－ＣＨ＝ＣＨ－、シクロアルキレン、シクロアルケニレン、又は－ＳｉＲ^１ _２－で置き換えられてもよく、置換又は非置換のアリールアルキル中のアルキレンにおいて、任意の水素はハロゲンで置換えられてもよく、任意の－ＣＨ_２－は、－Ｏ－、－ＣＨ＝ＣＨ－、シクロアルキレン、シクロアルケニレン、又は－ＳｉＲ^１ _２－で置き換えられてもよく、
ｎは１以上の整数を示す。 [5] The hydrogen polysilsesquioxane fine particles according to any one of [1] to [4], which contain hydrogen polysilsesquioxane represented by the following general formula (I).

In the formula, R ¹ , R ² , R ³ and R ⁴ are independently derived from hydrogen, substituted or unsubstituted alkyl having 1 to 45 carbon atoms, substituted or unsubstituted aryl, and substituted or unsubstituted aryl alkyl, respectively. A group selected from the group consisting of an alkyl having 1 to 45 carbon atoms, any hydrogen may be replaced with a halogen, and any -CH _2- is -O-, -CH = CH-,. It may be replaced with cycloalkylene, cycloalkenylene, or -SiR 12-, and in the alkylene in the substituted or unsubstituted arylalkyl, any hydrogen may be replaced with halogen, and ^any _{-CH 2-} , -O-, -CH = CH-, cycloalkylene, cycloalkenylene, or -SiR ¹² _- may be replaced.
n represents an integer of 1 or more.

式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４はそれぞれ独立に、水素、炭素数１～４５の置換又は非置換のアルキル、置換又は非置換のアリール、及び置換又は非置換のアリールアルキルからなる群から選択される基であり、炭素数の１～４５のアルキルにおいて、任意の水素はハロゲンで置き換えられてもよく、任意の－ＣＨ_２－は、－Ｏ－、－ＣＨ＝ＣＨ－、シクロアルキレン、シクロアルケニレン、又は－ＳｉＲ^１ _２－で置き換えられてもよく、置換又は非置換のアリールアルキル中のアルキレンにおいて、任意の水素はハロゲンで置換えられてもよく、任意の－ＣＨ_２－は、－Ｏ－、－ＣＨ＝ＣＨ－、シクロアルキレン、シクロアルケニレン、又は－ＳｉＲ^１ _２－で置き換えられてもよく、
ｎは１以上の整数を示す。 [6] The hydrogen polysilsesquioxane fine particles according to any one of [1] to [5], which contain hydrogen polysilsesquioxane represented by the following general formula (II):

In the formula, R ¹ , R ² , R ³ and R ⁴ are independently derived from hydrogen, substituted or unsubstituted alkyl having 1 to 45 carbon atoms, substituted or unsubstituted aryl, and substituted or unsubstituted aryl alkyl, respectively. A group selected from the group consisting of an alkyl having 1 to 45 carbon atoms, any hydrogen may be replaced with a halogen, and any -CH _2- is -O-, -CH = CH-,. It may be replaced with cycloalkylene, cycloalkenylene, or -SiR 12-, and in the alkylene in the substituted or unsubstituted arylalkyl, any hydrogen may be replaced with halogen, and ^any _{-CH 2-} , -O-, -CH = CH-, cycloalkylene, cycloalkenylene, or -SiR ¹² _- may be replaced.
n represents an integer of 1 or more.

[7] The hydrogen polysil according to any one of [1] to [6], which comprises a hydrogen polysil sesquioxane represented by any one of the following general formulas (III) to (V). Sesquioxane fine particles:

[8] The method for producing hydrogen polysilsesquioxane fine particles according to any one of [1] to [7], which comprises the following step (p):
(P) In a solution system in which a silicon compound represented by the following general formula (VI) is present, the silicon compound is hydrolyzed and polycondensed, and at the same time, phase separation of the solution system is promoted to promote the phase separation of the solution system. Producing oxane fine particles,
HSi (R) ₃ ... (VI)
(In the formula, R is a hydrolyzable functional group, and R may be the same as or different from each other).

[9] In the general formula (VI), R is a halogen, hydrogen, substituted or unsubstituted alkoxy having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy having 6 to 20 carbon atoms, and 7 to 30 carbon atoms. Substituentally substituted or unsubstituted alkoxy having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy having 6 to 20 carbon atoms, and 7 to 30 carbon atoms, which are groups selected from the substituted or unsubstituted arylalkoxy of. The method according to [8], wherein in the substituted or unsubstituted arylalkoxy, any hydrogen may be substituted with a halogen, and R may be the same as or different from each other.

[10] The method according to [8] or [9], wherein the solution system contains a phase separation inducer that promotes phase separation of the solution system.
[11] The method according to [10], wherein the phase separation inducer is a hydrogen-bonding substance.
[12] The method according to [10] or [11], wherein the phase separation inducer is a water-soluble polymer.
[13] The method according to any one of [10] to [12], wherein the phase separation inducer is polyacrylic acid or a salt thereof.

[14] The method according to any one of [10] to [13], wherein the solution system further contains a substance that suppresses hydrolysis and polycondensation of the silicon compound.
[15] The method according to [14], wherein the substance that suppresses hydrolysis and polycondensation of the silicon compound is a polar solvent.
[16] The polar solvent is at least one selected from the group consisting of alcohol, acetone, acetonitrile, N-methyl-2-pyrrolidone, N, N-dimethylformamide, and dimethyl sulfoxide, according to [15]. the method of.
[17] The method according to [15], wherein the polar solvent is alcohol.

[18] The method according to any one of [10] to [17], wherein the step (p) is carried out by adding the silicon compound to a solution containing at least a phase separation inducer and water in advance. Method.
[19] The method according to [18], wherein the solution containing at least the phase separation inducer and water in advance further comprises a catalyst for promoting hydrolysis and polycondensation of the silicon compound.

[20] The method according to [18] or [19], further comprising the following step (p') prior to step (p):
(P') To prepare a solution containing at least the phase separation inducer and water in advance.
[21] The silicon compound is a compound selected from trihalogenated silane, dihalogenated silane, trialkoxysilane, dialkoxysilane, aryloxysilane, aryloxysilane, and aryloxyalkoxysilane. [8] The method according to any one of [20].

[22] The method according to any one of [8] to [21], wherein the silicon compound is trihalogenated silane or trialkoxysilane.
[23] The method according to any one of [8] to [22], further comprising the following step (q).
(Q) Washing and / or drying the hydrogen polysilsesquioxane fine particles produced in step (p) with a predetermined solvent.

[24] A method for producing silicon oxide fine particles, which comprises the following step (r):
(R) The silicon oxide fine particles are produced by heat-treating the hydrogen polysilsesquioxane fine particles according to any one of [1] to [8] in a non-oxidizing gas atmosphere, wherein the silicon oxide fine particles are produced. It is assumed that the silicon compound fine particles have a volume-based cumulative 50% particle diameter D50 of less than 1 mm and a substantially spherical shape in the particle size distribution.
[25] The method according to [24], wherein the silicon oxide fine particles have an elemental composition represented by the general formula SiOxHy (1 <x <1.8, 0.01 <y <0.4).
[26] The method according to [24] or [25], wherein the non-oxidizing gas atmosphere is an inert gas.

[27] The method according to any one of [24] to [26], wherein the hydrogen polysilsesquioxane fine particles are heat-treated at a predetermined temperature in the range of 600 ° C. to 900 ° C. in the step (r). ..
[28] The method according to any one of [24] to [27], further comprising the following step (p) before the step (r):
(P) In a solution system containing a silicon compound represented by the following general formula (VI), the silicon compound is hydrolyzed and polycondensed, and phase separation of the solution system is promoted to obtain the hydrogen polysilsesquioxane fine particles. To generate,
HSi (R) ₃ ... (VI)
(In the formula, R is a hydrolyzable functional group, and R may be the same as or different from each other).

[29] Silicon oxide fine particles satisfying the following conditions (x), (y) and (z):
(X) 50% cumulative mass in the particle size distribution Particle size distribution diameter D50 is in the range of nanometers or micrometers;
(Y) Being substantially spherical; and (z) having an elemental composition represented by the general formula SiOxHy (1 <x <1.8, 0.01 <y <0.4).

[30] The silicon oxide fine particles according to [29], wherein the 50% cumulative mass particle size distribution diameter D50 is 80 μm or less.
[31] The water silicon oxide fine particles according to [29] or [30], wherein the 50% cumulative mass particle size distribution diameter D50 is a predetermined value in the range of 100 nm to 50 μm.
[32] The silicon oxide fine particles according to any one of [29] to [31], wherein the 50% cumulative mass particle size distribution diameter D50 is a predetermined value in the range of 500 nm to 10 μm.

[33] A negative electrode active material for a secondary battery, which comprises the silicon oxide fine particles according to any one of [29] to [32].
[34] A negative electrode for a secondary battery, which comprises the negative electrode active material for a secondary battery according to [33].
[35] A secondary battery comprising the negative electrode for the secondary battery according to [34].
[36] The secondary battery according to [35], which is a lithium ion secondary battery.

According to the present invention, it is possible to provide substantially spherical hydrogen polysilsesquioxane fine particles and substantially spherical silicon oxide fine particles. In addition, according to the present invention, the particle size can be controlled in a smaller range. Furthermore, according to the present invention, it is possible to secure a high electrode density in the secondary battery, and as a result, it is possible to realize a high capacity.

It is a figure which shows the SEM photograph of the hydrogen polysilsesquioxane and the silicon oxide obtained in Example 1. FIG. It is a figure which shows the SEM photograph of the hydrogen polysilsesquioxane obtained in Example 2. FIG. It is a figure which shows the SEM photograph of the hydrogen polysilsesquioxane obtained in the comparative example 1. FIG. It is a figure which shows the photograph of the hydrogen polysilsesquioxane and the silicon oxide obtained in the comparative example 2, and the SEM photograph of the silicon oxide. It is a figure which shows the result of having measured the particle size distribution about the silicon oxide obtained in Example 1 and Comparative Example 1, respectively. It is a figure which shows the result of the cycle test about the lithium ion secondary battery produced in Example 1 and Comparative Example 1, respectively. This is a configuration example of a coin-type lithium-ion battery.

<Hydrogen polysilsesquioxane fine particles>
The hydrogen polysilsesquioxane fine particles according to the present invention are characterized in that the 50% cumulative mass particle size distribution diameter D50 in the particle size distribution is less than 1 mm and is substantially spherical.

In the present invention, the "50% cumulative mass particle size distribution diameter D50 in the particle size distribution" may be interpreted as known to those skilled in the art, and specifically, a particle size distribution measuring device based on a laser diffraction / scattering method (a particle size distribution measuring device). It refers to the volume average particle diameter at which the cumulative distribution value is 50% in the volume-based particle size distribution acquired by the laser diffraction type particle size distribution measuring device).
The present invention requires that the 50% cumulative mass particle size distribution diameter D50 be less than 1 mm. In the present invention, the 50% cumulative mass particle size distribution diameter D50 may be appropriately adjusted within the range of less than 1 mm so as to exhibit various desired physical properties and functions, but more specifically, it is in the range of nanometers or micrometers. Can be mentioned. In particular, when hydrogen polysilsesquioxane fine particles are converted into silicon oxide by heat treatment and the silicon oxide is used as a negative electrode active material for a secondary battery, the 50% cumulative mass particle size distribution diameter D50 is It is preferably 80 μm or less, more preferably 100 nm to 80 μm, still more preferably about 100 nm to 50 μm, and in some cases about 500 nm to 10 μm.

As described above, the hydrogen polysilsesquioxane fine particles according to the present invention are further characterized by being substantially spherical. The significance that the hydrogen polysilsesquioxane fine particles in the present invention are substantially spherical is described below.
So far, polysilsesquioxane synthesized by hydrolysis and polymerization reaction of a trifunctional organosilane compound having an organic functional group such as an alkyl group or a phenyl group in the side chain has been hydrolyzed and polymerized under predetermined conditions. There are examples of synthesizing substantially spherical polysilsesquioxane by controlling the reaction. However, conventionally, hydrogen polysilsesquioxane synthesized by hydrolysis and polymerization reaction of a trifunctional silane compound (for example, trichlorosilane, trimethoxysilane) having hydrogen in the side chain is an atypical aggregate (Fig.). Only examples of 3) and those synthesized in the form of monolith structure, vesicle structure, etc., even if they are controlled to a certain shape, have been reported (Patent Document 5 and Non-Patent Document 1), and substantially spherical fine particles. There is no example of synthesizing hydrogen polysilsesquioxane.
That is, in the present invention, the terms "substantially spherical", "substantially spherical hydrogen polysilsesquioxane fine particles" and the like refer to the hydrogen polysilsesquioxane fine particles according to the present invention in a shape from the conventional hydrogen polysilsesquioxane. It is used with the intention of distinguishing from the aspect of.
The reason why the substantially spherical hydrogen polysilsesquioxane fine particles can be synthesized in the present invention will be described later.

In addition, the fact that hydrogen polysilsesquioxane is a substantially spherical fine particle can be confirmed by electron microscope observation using, for example, an SEM or a transmission electron microscope (TEM). Considering operability and acquisition of a detailed profile of hydrogen polysilsesquioxane, electron microscopic observation using an SEM is preferable. As shown in the examples of SEM photographs (FIGS. 1 and 2) of hydrogen polysilsesquioxane obtained in the following examples, in addition to being able to confirm that hydrogen polysilsesquioxane is a substantially spherical fine particle. This is because it is possible to measure a rough particle size.

The "hydrogen polysilsesquioxane" referred to in the present invention may be interpreted as generally understood by those skilled in the art, specifically [RSiO _3/2 ] _n (R is a predetermined chemical group, n is a silsesquioxane having a trifunctional siloxane structural unit (T structure) represented by an arbitrary integer of 1 or more, in which R is H (hydrogen) ([HSiO _3/2 ] _n ; ^TH _n , n is an arbitrary integer of 1 or more.)
Further, the polysilsesquioxane containing the hydrogen polysylsesquioxane of the present invention has, for example, a ladder type, a basket type (complete basket type, an incomplete basket type), a random structure type, and a combination thereof. The structure adopted in the present invention is not particularly limited and may be of any type.

More specifically, as an example of hydrogen polysilsesquioxane which is a component of the hydrogen polysilsesquioxane fine particles according to the present invention, for example, a ladder-type hydrogen polysilsesquioxane represented by the following chemical formula (I). Can be mentioned.

式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４はそれぞれ独立に、水素、炭素数１～４５の置換又は非置換のアルキル、置換又は非置換のアリール、及び置換又は非置換のアリールアルキルからなる群から選択される基であり、炭素数の１～４５のアルキル基において、任意の水素はハロゲンで置き換えられてもよく、任意の－ＣＨ_２－は、－Ｏ－、－ＣＨ＝ＣＨ－、シクロアルキレン、シクロアルケニレン、又は－ＳｉＲ^１ _２－で置き換えられてもよく、置換又は非置換のアリールアルキル中のアルキレンにおいて、任意の水素はハロゲンで置換えられてもよく、任意の－ＣＨ_２－は、－Ｏ－、－ＣＨ＝ＣＨ－、シクロアルキレン、シクロアルケニレン、又は－ＳｉＲ^１ _２－で置き換えられてもよく、
ｎは１以上の整数を示す。
本発明において、「ハロゲン」は、字義通りに理解され、フッ素、塩素、臭素、ヨウ素などを示すが、中でもフッ素または塩素が好ましい。

In the formula, R ¹ , R ² , R ³ and R ⁴ are independently derived from hydrogen, substituted or unsubstituted alkyl having 1 to 45 carbon atoms, substituted or unsubstituted aryl, and substituted or unsubstituted aryl alkyl, respectively. A group selected from the group consisting of an alkyl group having 1 to 45 carbon atoms, any hydrogen may be replaced with a halogen, and any -CH _2- is -O-, -CH = CH-. , Cycloalkylene, cycloalkenylene, or —SiR ¹² −, and in the alkylene in the substituted or unsubstituted arylalkyl, any hydrogen may be substituted with halogen, any _{−CH 2 −} . May be replaced with -O-, -CH ₌ CH-, cycloalkylene, cycloalkenylene, or -SiR ^12- .
n represents an integer of 1 or more.
In the present invention, "halogen" is literally understood and refers to fluorine, chlorine, bromine, iodine and the like, with fluorine or chlorine being preferred.

Further, examples of the ladder-type hydrogen polysilsesquioxane that can be preferably adopted as a component of the hydrogen polysilsesquioxane in the present invention include those represented by the following general formula (II).

In the formula, R ¹ , R ² , R ³ and R ⁴ are as defined in the general formula (I).

なお、化学式（ＩＩＩ）、（ＩＶ）及び（Ｖ）で表される水素ポリシルセスキオキサン構造はそれぞれ順にＴ^Ｈ _６、Ｔ^Ｈ _８、Ｔ^Ｈ _１０である。
通常、以下のシラン化合物の加水分解及び重縮合反応では、各種構造の水素ポリシルセスキオキサンが所定の収率で合成される。本発明の水素ポリシルセスキオキサン微粒子は、このように各種構造の水素ポリシルセスキオキサンの混合物から構成されるものであってもよいし、又は特定の構造の水素ポリシルセスキオキサン一種から構成されるものであってもよい。 Further, specific examples of the cage-type hydrogen polysilsesquioxane include those having a chemical structure represented by the following chemical formulas (III), (IV) and (V), respectively.

The ^hydrogen polysilsesquioxane structures represented by the chemical formulas (III), (IV) and (V) are TH ₆ , ^TH ₈ , and ^TH ₁₀ , respectively.
Usually, in the following hydrolysis and polycondensation reactions of silane compounds, hydrogen polysilsesquioxane having various structures is synthesized in a predetermined yield. The hydrogen polysilsesquioxane fine particles of the present invention may be composed of a mixture of hydrogen polysilsesquioxane having various structures as described above, or a kind of hydrogen polysilsesquioxane having a specific structure. It may be composed of.

<Manufacturing method of hydrogen polysilsesquioxane>
According to one aspect of the present invention, the above-mentioned method for producing hydrogen polysilsesquioxane fine particles is provided, and the method includes the following step (p).
(A) In a solution system containing a silicon compound represented by the following general formula (VI), the silicon compound is hydrolyzed and polycondensed, and at the same time, phase separation of the solution system is promoted to promote hydrogen polysilsesquioxane fine particles. To generate,
HSi (R) ₃ ... (VI)
In the formula, R is a hydrolyzable functional group, provided that R may be the same or different from each other.
Hereinafter, the step (p) will be described in detail.

(Silicon compound)
As described above, the silicon compound used as a raw material for the hydrogen polysilsesquioxane fine particles of the present invention is represented by the general formula (VI), has H (hydrogen) as a side chain in the central Si, and has H (hydrogen) as a side chain. Further, it is a silicon compound formed by binding three functional groups having hydrolyzability. As described above, since the silicon compound has a hydrolyzable functional group, hydrogen polysilsesquioxane is produced by hydrolyzing and polymerizing the compound as described later.

In the general formula (VI), examples of R, which is a hydrolyzable functional group, include halogen, hydrogen, substituted or unsubstituted alkoxy having 1 to 10 carbon atoms, and substituted or unsubstituted functional group having 6 to 20 carbon atoms. Examples include a group selected from aryloxy and substituted or unsubstituted arylalkoxy having 7 to 30 carbon atoms. Here, in substituted or unsubstituted alkoxy having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy having 6 to 20 carbon atoms, and substituted or unsubstituted arylalkoxy having 7 to 30 carbon atoms, any hydrogen may be used. It may be substituted with halogen, and R may be the same as or different from each other.

Further, specific examples of the silicon compound represented by the general formula (VI) include the following compounds.
Trihalogenated silanes such as trichlorosilane, trifluorosilane, tribromosilane, dichlorosilane, dihalogenated silane, trin-butoxysilane, trit-butoxysilane, trin-propoxysilane, trii-propoxysilane, din -Trialkoxysilanes such as butoxyethoxysilanes, triethoxysilanes, trimethoxysilanes and diethoxysilanes and dialkoxysilanes, as well as aryloxysilanes such as triaryloxysilanes, diaryloxysilanes and diaryloxyethoxysilanes or aryloxyalkoxy Silane.

Of these, trihalogenated silane or trialkoxysilane is preferable from the viewpoint of reaction and availability and manufacturing cost, and trihalogenated silane is particularly preferable.

These silicon compounds represented by the general formula (VI) may be used alone or in combination of two or more.

The silicon compound represented by the general formula (VI) has high hydrolyzability and condensation reactivity, and not only a hydrogen silsesquioxane polymer (HPSQ) can be easily obtained, but also heat treatment is performed in an inert gas atmosphere. Since it is easy to control the amount of Si—H bond of the silicon oxide obtained at that time, the embodiment using these silicon compounds can be particularly preferably adopted in the present invention.

(solvent)
The solvent constituting the reaction solution in the step (p) is not particularly limited as long as it promotes hydrolysis / polycondensation of the silicon compound. Specifically, water may be contained to assist the hydrolysis of the siliconized compound, but in addition to water, alcohols such as methanol, ethanol and 2-propanol, ethers such as diethyl ether, acetone, methyl ethyl ketone and the like can be contained. Examples thereof include organic solvents containing aromatic hydrocarbon solvents such as ketones, hexane, DMF, and toluene. These may be used alone or in combination of two or more.
In the present invention, as a substance that suppresses hydrolysis and polycondensation of the silicon compound, as described later, alcohols such as methanol, ethanol and 2-propanol, ethers such as diethyl ether, acetone, methyl ethyl ketone, hexane and DMF Etc. may contain organic solvents such as. In the present invention, when these substances are contained in a solution system, the substances are understood as substances that suppress the hydrolysis and polycondensation of silicon compounds, but also function as the "solvent" in the present invention. It should be understood as a substance. That is, the entire solvent including these substances may be understood as the "solvent" in the present invention.

(catalyst)
The reaction solution in the step (p) may optionally contain a catalyst that promotes hydrolysis and polycondensation of the siliconized compound. Specific examples of such a catalyst include an acidic catalyst and a basic catalyst, which may be used alone or in combination with an acidic catalyst and a basic catalyst.
As the acidic catalyst, either an organic acid or an inorganic acid can be used.
Specific examples of the organic acid include formic acid, acetic acid, propionic acid, oxalic acid, and citric acid, and examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. Among these, hydrochloric acid and acetic acid are preferably used because the hydrolysis reaction and the subsequent polycondensation reaction can be easily controlled, the cost is low, and the treatment after the reaction is easy.

Examples of the basic catalyst include basic compounds such as sodium hydroxide, calcium hydroxide, and potassium hydroxide, ammonium tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, and benzyltriethylammonium. Examples thereof include quaternary ammonium salts such as hydroxydo, ammonium fluoride, tetrabutylammonium fluoride, benzyltrimethylammonium chloride and benzyltriethylammonium chloride.

When a halogenated silane such as trichlorosilane is used as the silicon compound, an acidic aqueous solution is formed in the presence of water, and the hydrolysis and polycondensation reaction proceed without the addition of an acidic catalyst. There is no need to add separately.
Therefore, the catalyst is an optional component in step (p).

(Conditions for hydrolysis and polycondensation reaction)
Next, the reaction conditions for hydrolysis and polycondensation in step (p) will be described.

The ratio of the silicon compound in the reaction solution is not particularly limited, but is, for example, about 0.1 part by mass to about 50 parts by mass, preferably about 0.1 part by mass with respect to 100 parts by mass of the reaction solution. From about 45 parts by mass, more preferably from about 0.5 parts by mass to about 40 parts by mass, particularly preferably from about 0.5 parts by mass to about 35 parts by mass, and in some cases from about 0.5 parts by mass to about 25 parts by mass. It is about 0.5 parts by mass to about 20 parts by mass.

The ratio of the solvent is not particularly limited as long as the hydrolysis and polycondensation reaction proceeds, but is, for example, about 100 parts by mass to about 1500 parts by mass, preferably about 150 parts by mass with respect to 100 parts by mass of the silicon compound. From about 1400 parts by mass, more preferably from about 200 parts by mass to about 1300 parts by mass, and in some cases from about 230 parts by mass to about 1200 parts by mass, and from about 250 parts by mass to about 600 parts by mass. When these ratio ranges are adopted, only water may be used as the solvent as described above, or a mixed solvent of water and other solvents (alcohol, organic solvent, etc.) may be used.

When the catalyst is added, the ratio thereof may be appropriately adjusted so as to obtain the desired hydrolysis and polycondensation reaction, and is not particularly limited, but is, for example, about 100 parts by mass of the silicon compound. From 0.02 parts by mass to about 15 parts by mass, preferably from about 0.02 parts by mass to about 10 parts by mass, more preferably from about 0.02 to about 8 parts by mass, and in some cases from about 0.04 parts to about 7 parts by mass. Parts, from about 0.08 parts by mass to about 6 parts by mass.

The pH of the reaction solution may be appropriately adjusted so that the hydrolysis and polycondensation reaction of the silicon compound proceed satisfactorily, and is not particularly limited, but is usually about 0.8 to 7, preferably about 2 to 7. The degree, depending on the case, about 3 to 7, and about 3.5 to 6 can be mentioned.
For adjusting the pH of the reaction solution, an acid or base containing the above-mentioned acidic catalyst and basic catalyst can be used.

The order of addition and the method of addition of each component are not particularly limited, but for example, the solvent and optionally the catalyst solution are put into the reaction vessel, and the atmosphere in the reaction vessel is arbitrarily changed to a predetermined gas atmosphere (for example, nitrogen). , Argon, helium, or other inert gas), then add (drop) the above silicon compound to the water in the reaction vessel under stirring, and hydrolyze the reaction solution at a predetermined reaction temperature and reaction time while stirring. And the polycondensation reaction can be carried out.

Further, the reaction temperature of hydrolysis and polycondensation is not particularly limited, but is, for example, about −20 ° C. to about 90 ° C., preferably about 0 ° C. to about 90 ° C., more preferably about 0 ° C. to about 86 ° C. ° C., from about 10 ° C. to about 85 ° C., and in some cases, normal temperature (eg room temperature; about 20 ° C. to 25 ° C.). The reaction time is also not particularly limited, but is, for example, about 0.5 hours to about 100 hours, in some cases about 0.5 hours to about 80 hours, about 0.5 hours to about 6 hours, and in some cases. About 0.5 hours to about 5 hours can be mentioned.
Furthermore, in step (p), in consideration of its productivity and production cost, it is preferable to carry out the hydrolysis and the polycondensation reaction in parallel under the same conditions in one reactor.

(Progress of phase separation of solution system)
In step (p), in order to produce substantially spherical hydrogen polysilsesquioxane fine particles according to the present invention, hydrogen polysilsesquioxane produced at the same time as hydrolysis and polycondensation of the above silicon compound is produced. It is necessary to proceed with the phase separation of the containing solution system. In other words, in the present invention, terms such as "progressing phase separation of a solution system" have a 50% cumulative mass particle size distribution diameter D50 in a predetermined range as described above, and are substantially spherical hydrogen polysilsesquioxane. The phase separation of the above solution system must be promoted to the extent and mode that causes fine particles to be generated.

So far, the present inventors have synthesized hydrogen polysilcesquioxane by dropping the above-mentioned silicon compound into a mixed solution of a predetermined acid acting as a catalyst and a solvent containing water. According to such an aspect of synthesis, hydrogen polysilsesquioxane is produced in the form of an agglomerate of amorphous fine particles. The reason is that in the case of a silicon compound having hydrogen in the side chain which is a raw material of hydrogen polysilsesquioxane, unlike a trifunctional organosilane compound, when it is dropped into the solution containing water and acid, it is immediately after that. It is presumed that agglomerate-like hydrogen polysilesquioxane products are produced due to the rapid hydrolysis and polymerization initiation.
Therefore, in the present invention, hydrogen polysilsesqui is produced in the solution system to the extent and in an embodiment that causes the hydrogen polysilsesquioxane fine particles of the present invention to be produced at the same time as the hydrolysis and polycondensation of the silicon compound in the solution system. It is adopted as a configuration to promote the phase separation between the solid phase of oxane and the liquid phase of the other solution part.

The progress of the phase separation of the solution system is not particularly limited, but a configuration using a phase separation inducer that promotes the phase separation of the solution system can be adopted.
Specific examples of the phase separation inducer include hydrogen-bonding substances. Such hydrogen-bonding substances include water-soluble polymers, water-soluble surfactants, and the like, and more specifically, the following substances can be mentioned:
Natural water-soluble polymers such as alginic acid, pectin, and dextran; cellulose-based polymers such as carboxylmethylcellulose and hydroxyethylcellulose; polyacrylic acid or salts thereof (for example, sodium polyacrylate), polyacrylamide, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, polyvinyl. Synthetic water-soluble polymers such as pyrrolidone; cationic surfactants such as alkyltrimethylammonium salts.
Of these, it is preferable to use polyacrylic acid or a salt thereof in that the phase separation of the solution system can be reliably promoted to form the spherical hydrogen polysilsesquioxane fine particles specified in the present invention.
The phase separation inducer may be used alone or in combination of two or more.

In the present invention, the phase separation inducer and the amount thereof are not particularly limited as long as they can cause phase separation of the solution system to the extent that the hydrogen polysilsesquioxane fine particles prescribed in the present invention can be produced, but the above is not particularly limited. About 1 to 600 parts by mass, preferably about 1 to 500 parts by mass, more preferably about 10 to 400 parts by mass, still more preferably about 50 to 300 parts by mass, and particularly preferably about about 1 part by mass with respect to 100 parts by mass of the silicon compound. It is 80 parts by mass to 250 parts by mass, and in some cases, about 80 to 150 parts by mass.

Further, the solution system in the present invention may optionally contain a substance that suppresses hydrolysis and polycondensation of the silicon compound. By including such a substance in the solution system, it is possible to suppress the excessive progress of hydrolysis and polycondensation reaction of the silicon compound, and it is possible to prevent hydrogen polysilsesquioxane from being formed as an amorphous agglomerate. However, the hydrogen polysilsesquioxane of the present invention is sufficient if each particle is substantially spherical, and includes a case where such substantially spherical particles are produced in a state of being aggregated to a certain extent. Therefore, in the solution system of the present invention, the substance that suppresses the hydrolysis and polycondensation of the silicon compound is an optional component.

Specific examples of the substance that suppresses hydrolysis and polycondensation of the silicon compound include a polar solvent, for example, alcohols such as methanol, ethanol and propanol (1-propanol, 2-propanol), acetone, acetonitrile and N. -Methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) can be mentioned.
As the substance that suppresses the hydrolysis and polycondensation of the silicon compound, one kind may be used alone, or two or more kinds may be used in combination.

Further, when the above-mentioned silicon compound as a raw material has an alkoxy group as a hydrolyzable functional group, a configuration in which the alkoxy group and an alcohol having a carbon number of carbons are adopted can be mentioned as a preferred embodiment. More specifically, for example, when trimethoxysilane is used as the raw material silicon compound, methanol is preferably used as the phase separation inducer, and ethanol is used when triethoxysilane is used. preferable.

In the present invention, the amount of the substance that suppresses the hydrolysis and polycondensation of the silicon compound is not particularly limited, but is 1 to 600 parts by mass, preferably 1 to 500 parts by mass with respect to 100 parts by mass of the silicon compound. Parts, more preferably 10 to 400 parts by mass, still more preferably 50 to 300 parts by mass, particularly preferably 80 parts by mass to 250 parts by mass, and in some cases 80 to 150 parts by mass.

Furthermore, in the present invention, when it is desired to generate hydrogen polysilsesquioxane fine particles having higher sphericity and to suppress the aggregation of these fine particles, hydrolysis and polymerization of the phase separation inducer and the silicon compound are performed. It is preferable to combine it with a substance that suppresses condensation. As a particularly preferable embodiment, a combination of a water-soluble polymer and an alcohol is preferable.

As a more preferable embodiment, as the silicon compound, a hydrolyzable functional group having an alkoxy group having an arbitrary carbon number is used, and i) an alcohol having the same carbon number as the alkoxy group (of the silicon compound). Substances that suppress hydrolysis and polycondensation); and / or ii) configurations using a water-soluble polymer (phase separation inducer) can be mentioned. In this case, it is particularly preferable that the amount of the alcohol and the water-soluble polymer added is in the numerical range described for the phase separation inducer and the substance that suppresses the hydrolysis and polycondensation of the silicon compound.

A particularly preferable embodiment is a solution system having the following composition.
(I) A catalyst in an amount that appropriately promotes the hydrolysis and polycondensation reaction of the silicon compound (specifically, the range of the above-mentioned various addition amounts);
(Ii) 100 to 500 parts by mass, preferably 200 to 400 parts by mass, of a solvent mainly containing water (for example, a solvent in which 90% or more is water, preferably a solvent containing only water) with respect to 100 parts by mass of the silicon compound. In some cases, 250 to 350 parts by mass; and (iii) a water-soluble polymer (phase separating agent) and an alcohol (a substance that suppresses hydrolysis and polycondensation of a silicon compound) are added to, for example, 1 part by mass with respect to 100 parts by mass of the above silicon compound. ~ 300 parts by mass, preferably 10 to 250 parts by mass, more preferably 60 to 150 parts by mass, and in some cases 80 to 150 parts by mass.

Further, the order in which each component is added / mixed is not particularly limited as long as the substantially spherical hydrogen polysilsesquioxane fine particles of the present invention can be produced, but for example, if the following procedure is adopted, it is more reliable. It is possible to produce substantially spherical hydrogen polysilsesquioxane fine particles prescribed in the present invention.
That is, in step (p), the silicon is added (for example, dropped) to a solution containing water and a phase separation inducer and optionally a substance that suppresses hydrolysis and polycondensation of the silicon compound. The compound can be hydrolyzed and polycondensed and at the same time phase separation can proceed in the solution system. In this case, the solution containing the above-mentioned phase separation inducer and optionally a substance that suppresses hydrolysis and polycondensation of the silicon compound and water may optionally contain the above-mentioned catalyst, but hydrolysis and optionally adding a catalyst are not required. A catalyst is not essential if polycondensation proceeds. For example, when trichlorosilane is adopted as the silicon compound, hydrolysis and polycondensation proceed without adding a catalyst such as an acid.
In addition, in order to generate substantially spherical hydrogen polysilsesquioxane fine particles in which a uniform reaction is generated and aggregation is reduced, it is preferable to add the silicon compound to the solution under stirring.

As described above, in the method for producing hydrogen polysilsesquioxane fine particles of the present invention, a solution containing a phase separation inducer prepared in advance and a substance optionally suppressing the hydrolysis and polycondensation of a silicon compound and water is used. Since the embodiment of adding the silicon compound can be adopted, the production method comprises a phase separation inducer, optionally a substance that suppresses hydrolysis and polycondensation of the silicon compound, and water before the step (p). And optionally, pre-preparing a solution containing the catalyst (step (p')) may be included.

According to the embodiment in which the reaction system and the reaction procedure as described above are adopted, substantially spherical hydrogen polysilsesquioxane fine particles can be reliably generated in a state where aggregation is relatively suppressed.

The method for producing hydrogen polysilsesquioxane fine particles of the present invention may further optionally include at least one of the following steps.
(A) After synthesizing predetermined spherical hydrogen polysilsesquioxane fine particles through hydrolysis and polycondensation and phase separation of a solution system, optional filtration separation (for example, pressure filtration), solid-liquid separation, and solvent distillation are performed. The liquid fraction is separated and removed by a method such as separation, centrifugation or tilting, and the solid fraction is obtained as hydrogen polysilsesquioxane fine particles. As such a method for separating a solid content and a liquid, various general-purpose techniques are known to those skilled in the art, and they can be appropriately used.
(B) Further, the obtained solid fraction is washed with water or an organic solvent, and the organic solvent is distilled off, dried (dried under reduced pressure and / or dried by heating) or the like.

<Silicon oxide fine particles and their manufacturing method>
As yet another aspect, the present invention includes silicon oxide fine particles obtained by heat-treating the above-mentioned spherical hydrogen polysilcesquioxane fine particles, and a method for producing the same.
More specifically, the method for producing silicon oxide fine particles according to the present invention includes the following step (r).
(R) Silicon oxide fine particles are produced by heat-treating the above-mentioned hydrogen polysilsesquioxane fine particles in a non-oxidizing gas atmosphere, except that the silicon compound fine particles are 50% cumulative particles based on the volume in the particle size distribution. It is assumed that the diameter D50 is less than 1 mm and is substantially spherical.

The "non-oxidizing gas atmosphere" in the present invention includes an inert gas atmosphere, a reducing atmosphere, and a mixed atmosphere in which these atmospheres are used in combination. Examples of the inert gas atmosphere include inert gases such as nitrogen, argon, and helium, and these inert gases may be used alone or in combination of two or more. In addition, the inert gas may be any commonly used gas, but a high-purity standard gas is preferable. The reducing atmosphere includes an atmosphere containing a reducing gas such as hydrogen. For example, a mixed gas atmosphere of 2% by volume or more of hydrogen gas and an inert gas can be mentioned. In addition, the hydrogen gas atmosphere itself may be used as the reducing atmosphere in some cases.

Further, the heat treatment temperature is not particularly limited, and examples thereof include 400 ° C. to 2500 ° C., and in some cases, 500 ° C. to 2000 ° C. However, especially when the produced silicon oxide is used as a negative electrode active material for a secondary battery, it is necessary to leave an appropriate amount of Si—H bonds from the viewpoint of exhibiting both high capacity and good cycle characteristics. Become. The heat treatment temperature at which such an appropriate amount of Si—H bond remains is, for example, 600 ° C. to 1500 ° C. or higher, preferably 600 ° C. to 900 ° C., more preferably 650 ° C. to 850 ° C., and more preferably 759 ° C. to 850 ° C. Is.
In addition, when the gas is supplied into the heat treatment furnace, the flow rate may be appropriately adjusted according to the specifications of the heat treatment furnace to be adopted, and is not particularly limited. Examples of the gas flow rate include about 20 to 800 mL / min, and in some cases, about 30 to 700 mL / min and about 40 to 600 mL / min.

Further, the heat treatment time is usually about 30 minutes to 30 hours, preferably about 1 to 24 hours, more preferably about 1 to 16 hours, and in some cases about 1 to 12 hours, about 1 to 10 hours.

The heat treatment furnace that can be adopted in the present invention may be appropriately selected according to the intended purpose and is not particularly limited. For example, various heat treatment furnaces such as vacuum purge type tube furnace, rotary kiln type, roller herskin type, batch kiln type, pusher kiln type, mesh belt kiln type, carbon furnace, tunnel kiln type, shuttle kiln type, trolley elevating kiln type, etc. Can be mentioned. These heat treatment furnaces may be used alone or in combination of two or more. When two or more types are combined, the heat treatment furnaces may be connected in series or in parallel.

Further, the method for producing silicon oxide fine particles according to the present invention may appropriately include the above-mentioned steps that may be included in the method for producing hydrogen polysilsesquioxane fine particles according to the present invention prior to the step (r). It should be noted that well, the configuration of the method for producing silicon oxide fine particles including those steps is also an embodiment clearly disclosed herein.

Further, the silicon oxide fine particles provided by one aspect of the present invention satisfy the following conditions (x), (y) and (z).
(X) 50% cumulative mass in the particle size distribution Particle size distribution diameter D50 is in the range of nanometers or micrometers;
(Y) Being substantially spherical; and (z) having an elemental composition represented by the general formula SiOxHy (1 <x <1.8, 0.01 <y <0.4).

Here, with respect to the condition (x), the 50% cumulative mass particle size distribution diameter D50 corresponds to the above-mentioned D50 of the spherical hydrogen polysilsesquioxane fine particles, preferably 80 μm or less, more preferably 100 nm to 80 μm. Even more preferably, it is about 100 nm to 50 μm, and in some cases, about 500 nm to 10 μm.
Regarding the condition (y), as described for the hydrogen polysilsesquioxane fine particles, it can be confirmed that the silicon oxide fine particles are substantially spherical by microscopic observation (for example, electron microscopic observation using SEM, TEM, etc.). ..

Further, regarding the range of x in the condition (z), 1.2 <x <1.8, and further 1.3 <x <1.7, for example, x = 1.5, in some cases. Further, the range of y may be in the range of 0.1 <y <0.3 depending on the case.

Further, the silicon oxide according to the present invention has a peak 1 intensity (I ₁ ) derived from the Si—H bond at 820 to 920 cm ^-1 and 1000 to 1200 cm in the spectrum measured by infrared spectroscopy (IR). It may be a silicon oxide having a peak 2 intensity (I ₂ ) ratio (I ₁ / I ₂ ) derived from the Si—O—Si bond at ^-1 in the range of 0.01 to 0.35. ..

The ratio (I ₁ / I ₂ ) of the intensity of peak 1 (I ₁ ) to the intensity of peak 2 (I ₂ ) may be in the range of 0.01 to 0.30 and further 0.03 to 0.20. May be.

When the purpose is to produce silicon compound fine particles capable of exhibiting various good battery characteristics as a negative electrode active material in a secondary battery such as a lithium ion secondary battery, it is appropriately determined with reference to the above-mentioned disclosure of Patent Document 1, for example. You can also do it. Patent Document 1 discloses preferable ranges such as x and y in the above-mentioned general formula SiOxHy and a peak intensity ratio I ₁ / I ₂ in consideration of various battery characteristics of the secondary battery. Also in the present invention, the numerical range of each of these parameters disclosed in Patent Document 1 may be adopted. More specifically, it is defined by the above various parameters by appropriately adjusting various heat treatment conditions such as heat treatment temperature and heat treatment time at the time of heat treatment of the predetermined spherical hydrogen polysilsesquioxane fine particles of the present invention as a precursor. Physical characteristics can be realized.

<Negative electrode active material for secondary batteries and its manufacturing method>
According to the present invention, a negative electrode active material for a secondary battery and a method for producing the same are also disclosed.
The negative electrode active material for a secondary battery of the present invention may be one using the above-mentioned silicon oxide fine particles alone, but is produced by the method of the negative electrode active material for a secondary battery of the present invention as follows. It may be a composition.
In addition to the steps described below, the method may further include, optionally, a step that can be included in the above-mentioned method for producing hydrogen polysilsesquioxane fine particles and the method for producing silicon oxide fine particles, and the embodiments thereof. Is also expressly disclosed herein.

Batteries are required to have a high capacity and to be charged and discharged with a large current, so that a material having a low electrical resistance of an electrode is required.
Therefore, the method for producing a negative electrode active material of the present invention may further include a step of compounding or coating a carbon-based substance with the silicon oxide fine particles. In order to composite or coat the silicon oxide fine particles with a carbon-based substance, a method of dispersing the silicon oxide fine particles and the carbon-based substance by a mechanical mixing method using a mechanofusion, a ball mill, a vibration mill, or the like is used. Can be mentioned.

Preferred examples of the carbon-based material include carbon-based materials such as graphite, carbon black, fullerene, carbon nanotubes, carbon nanoforms, pitch-based carbon fibers, polyacrylonitrile-based carbon fibers, and amorphous carbon.

In the above-mentioned arbitrary compounding or coating step, the above-mentioned silicon oxide fine particles and the carbon-based substance may be mixed at an arbitrary ratio according to an appropriate purpose and so as to obtain desired battery characteristics.

<Manufacturing method of negative electrode>
According to still another aspect of the present invention, a method for manufacturing a negative electrode for a secondary battery is also disclosed. In this method, a negative electrode is manufactured using the negative electrode active material. The specific manufacturing process is shown below. In addition, in this method, each step which can be included in the said method for producing hydrogen polysilsesquioxane fine particles, the method for producing silicon oxide fine particles, and the method for producing a negative electrode active material is optional prior to each step shown below. May be included in the specification, and those embodiments are also expressly disclosed herein.

The negative electrode for a secondary battery is manufactured by using the above-mentioned silicon oxide fine particles or a negative electrode active material containing the above-mentioned silicon oxide fine particles in which the carbon-based substance is composited or coated.
For example, the negative electrode is based on a method of molding a negative electrode mixed material containing the negative electrode active material and optionally a binder into a certain shape, or a method of applying the negative electrode mixed material to a current collector such as a copper foil. It may be manufactured. The method for molding the negative electrode is not particularly limited, and any method may be used, and various known methods may be used.

More specifically, for example, first, a composition for a secondary battery negative electrode containing the negative electrode active material and optionally various additives such as a binder and a conductive material is prepared. The prepared composition for the negative electrode of the secondary battery may be directly coated on a current collector such as a rod-shaped body, a plate-shaped body, a foil-shaped body, or a net-like body mainly made of copper, nickel, stainless steel or the like. Alternatively, the composition for the negative electrode of the secondary battery is separately cast on a support, the negative electrode active material film formed on the support is peeled off, and the peeled negative electrode active material film is laminated on the current collector. A negative electrode plate may be formed. It should be noted that the above-mentioned form is merely an example, and it is needless to say that the form of the negative electrode is not limited to these and may be provided as another form.

As the binder, any one that can be used in a secondary battery is sufficient, for example, carboxymethyl cellulose, polyacrylic acid, alginic acid, glucomannan, amylose, saccharose and its derivatives and polymers, and each alkali metal salt. Other examples include polyimide resin and polyimide amide resin. These binders may be used alone or as a mixture of two or more.
Further, in addition to the binder, for example, the binding property between the current collector and the negative electrode active material is improved, the dispersibility of the unacceptable nuclear material is improved, and the conductivity of the binder itself is improved. Additives that can impart functions can also be added as needed. Specific examples of such additives include styrene-butadiene / rubber-based polymer, styrene-isoprene / rubber-based polymer, and the like.

<Secondary battery and its manufacturing method>
According to still another aspect of the present invention, a secondary battery and a method for manufacturing the secondary battery are also provided. The method includes manufacturing a secondary battery by using the negative electrode manufactured as described above.
The specific manufacturing process is shown below.
In addition to the steps shown below, the manufacturing method includes a method for manufacturing hydrogen polysilsesquioxane fine particles, a method for manufacturing silicon oxide fine particles, a method for manufacturing a negative electrode active material for a secondary battery, and a negative electrode for a secondary battery. Each step included in the production method of the above may be further included in advance, and those embodiments are also expressly disclosed in the present specification.

First, the secondary battery manufactured by the method for manufacturing the secondary battery according to the present invention may be appropriately designed in consideration of desired applications and functions, and its configuration is not particularly limited. The secondary battery can be configured by using the negative electrode according to the present invention with reference to the configuration of the existing secondary battery. In addition, the type of the secondary battery of the present invention is not particularly limited as long as the negative electrode can be applied, and examples thereof include a lithium ion secondary battery and a lithium ion polymer secondary battery. As demonstrated in the following examples, these batteries can be said to be a particularly preferable embodiment because the desired effects of the present invention can be exhibited.
Hereinafter, the manufacturing method and configuration of the lithium ion battery will be illustrated.

First, a positive electrode active material composition capable of reversibly occluding and releasing lithium ions is mixed with a positive electrode active material, a conductive auxiliary agent, a binder and a solvent to prepare a positive electrode active material composition. Similar to the negative electrode, the positive electrode active material composition is directly coated and dried on the metal current collector using various methods to prepare a positive electrode plate.
It is also possible to separately cast the positive electrode active material composition on a support, peel off the film formed on the support, and laminate the film on a metal current collector to manufacture a positive electrode. .. The method for forming the positive electrode is not particularly limited, but it can be formed by using various known methods.

As the positive electrode active material, a lithium metal composite oxide generally used in the field of the secondary battery can be used. For example, lithium cobaltate, lithium nickelate, lithium manganate with spinel structure, lithium cobalt manganate, iron phosphate with olivine structure, so-called ternary lithium metal composite oxide, nickel-based lithium metal composite oxide. And so on. Further, _V2O5 , _TiS , MoS and the like, which are compounds capable of de-inserting lithium ions, can also be used.

A conductive auxiliary agent may be added, and those generally used in lithium ion batteries can be used. It is preferably an electronically conductive material that does not decompose or deteriorate in the manufactured battery. Specific examples include carbon black (acetylene black and the like), graphite fine particles, vapor-grown carbon fibers, and a combination of two or more of these. Examples of the binder include vinylidene fluoride / propylene hexafluoride copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, ethylene polytetrafluoride and a mixture thereof, and styrene butadiene rubber. Examples include, but are not limited to, based polymers. Further, examples of the solvent include, but are not limited to, N-methylpyrrolidone, acetone, water and the like.
At this time, the contents of the positive electrode active material, the conductive auxiliary agent, the binder and the solvent are not particularly limited, but can be appropriately selected based on the amounts generally used in the lithium ion battery. ..

As the separator interposed between the positive electrode and the negative electrode, a separator generally used in a lithium ion battery may be used, but the separator is not particularly limited, and is appropriate in consideration of desired applications and functions. You can select it. Those having low resistance to ion transfer of the electrolyte or having excellent electrolytic solution impregnation ability are preferable. Specifically, it is a material selected from glass fiber, polyester, polyethylene, polypropylene, polytetrafluoroethylene, polyimide, or a compound thereof, and may be in the form of a non-woven fabric or a woven fabric.
More specifically, in the case of a lithium ion battery, a rewindable separator made of a material such as polyethylene or polypropylene is used, and in the case of a lithium ion polymer battery, a separator having an excellent ability to impregnate an organic electrolytic solution is used. It is preferable to use.

As the electrolytic solution, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, butylene carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyl tetrahydrofuran, γ-butyrolactone, dioxolan, 4 -Hexfluoride in a solvent such as methyldioxolane, N, N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, or a mixed solvent thereof. Lithium phosphorus, lithium tetrafluoride, lithium hexaantimon, lithium hexafluoride, lithium perchlorate, lithium trifluoromethanesulfonate, Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiSbF ₆ , One of the electrolytes consisting of lithium salts such as LiAlO ₄ , LiAlCl ₄ , LiN (C _x F _{2x + 1} SO ₂ ) (Cy F _{2y + 1} SO ₂ ) (where x and _y are natural numbers), LiCl, LiI, or any of them. A mixture of two or more types can be used.

In addition, various other non-aqueous electrolytes and solid electrolytes can also be used. For example, various ionic liquids to which lithium ions have been added, pseudo solid electrolytes in which ionic liquids and fine powders are mixed, lithium ion conductive solid electrolytes, and the like can be used.

Furthermore, for the purpose of improving the charge / discharge cycle characteristics, the above electrolytic solution may appropriately contain a compound that promotes stable film formation on the surface of the negative electrode active material. For example, vinylene carbonate (VC), fluorobenzene, cyclic fluorinated carbonate [fluoroethylene carbonate (FEC), trifluoropropylene carbonate (TFPC), etc.], or chain fluorinated carbonate [trifluorodimethyl carbonate (TFDMC), etc.]. Fluorinated carbonates such as trifluorodiethyl carbonate (TFDEC), trifluoroethylmethyl carbonate (TFEMC), etc.] are effective. The cyclic fluorinated carbonate and the chain fluorinated carbonate can also be used as a solvent, such as ethylene carbonate.

A separator is arranged between the positive electrode plate and the negative electrode plate as described above to form a battery structure. A lithium ion battery is completed by winding or folding the battery structure and placing it in a cylindrical battery case or a square battery case, and then injecting an electrolytic solution.

Further, after laminating the above battery structure in a bicell structure, impregnating it with an organic electrolytic solution, putting the obtained product in a pouch and sealing it, a lithium ion polymer battery is completed.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

In this example, various analyzes and evaluations were performed on the hydrogen polysilsesquioxane prepared in Examples 1 and 2 and Comparative Examples 1 and 2 and the silicon oxide obtained by heat-treating them.
The measuring device and measuring method of "elemental analysis measurement" and "evaluation of battery characteristics" in each Example and Comparative Example are as follows.

(Elemental analysis)
For elemental composition analysis, after solidifying the sample powder into pellets, the sample is irradiated with He ions accelerated to 2.3 MeV, and the energy spectrum of the backscattered particles and the energy spectrum of the forwardly scattered hydrogen atoms are analyzed. This was performed by the RBS (Razaford Back Scattering Analysis) / HFS (Hydrogen Forward Scattering Analysis) method, which gives a highly accurate composition value including hydrogen. The measuring device was a Pelletron 3SDH manufactured by National Electrostatics Corporation. Incident ion: 2.3MeVHe, RBS / HFS simultaneous measurement incident angle: 75deg. , Scattering angle: 160 deg. , Sample current: 4 nA, beam diameter: 2 mmφ.

(Measurement of particle size distribution)
The particle size distribution was measured by a laser diffraction / scattering type particle size measuring device (MT-3300EX II manufactured by Microtrac Bell), and the sample powder was dispersed in pure water by an ultrasonic homogenizer and measured by a laser diffraction method.

(BET specific surface area)
The BET specific surface area is determined by putting 1 g of the sample powder into the measurement cell, drying it at 250 ° C. for 2 hours using a mantle heater while purging with nitrogen gas, cooling it to room temperature over 1 hour, and then cooling it to room temperature, manufactured by Malvern, Nove 4200e. Measured at.

(Evaluation of battery characteristics)
The charge / discharge characteristics of a lithium ion secondary battery or the like using the negative electrode active material containing the silicon oxide of the present invention were measured as follows.
Using BTS2005W manufactured by Nagano Co., Ltd., the Li electrode is constantly charged with a current of 100 mA per 1 g of silicon oxide until it reaches 0.001 V, and then the current is maintained while maintaining the voltage of 0.001 V. Constant voltage charging was carried out until the current value was 20 mA or less per 1 g of the active material.
After a rest period of about 30 minutes, the fully charged cell was discharged at a constant current with a current of 100 mA per 1 g of the active material until the voltage reached 1.5 V.
The charge capacity was calculated from the integrated current value until the constant voltage charging was completed, and the discharge capacity was calculated from the integrated current value until the battery voltage reached 1.5 V. At the time of switching each charge / discharge, the circuit was paused for 30 minutes.

The charge / discharge cycle characteristics were also performed under the same conditions.
The charge / discharge efficiency was defined as the ratio of the discharge capacity to the charge capacity of the first charge (first cycle of charge / discharge), and the capacity retention rate was defined as the ratio of the discharge capacity to the charge capacity of the first charge / discharge cycle.

[Example 1]
(Preparation of hydrogen polysilsesquioxane (HPSQ))
In this example, first, hydrogen polysilsesquioxane was synthesized using ethanol as a substance for suppressing hydrolysis and polycondensation reaction and polyacrylic acid as a phase separation inducer. The procedure is shown below.

In a 100 mL beaker, 0.02 g of acetic acid, 15 g of pure water, 5 g of ethanol and 5 g of polyacrylic acid (average molecular weight 25,000; manufactured by Wako Pure Chemical Industries, Ltd.) are charged, and the obtained mixture is stirred to obtain polyacrylic acid. Was dissolved. 5 g of triethoxysilane was added to the obtained solution, the mixture was stirred for 1 minute, placed in an oven together with the beaker, and heated at 80 ° C. for 1 hour.
After completion of the reaction, the reaction product was filtered using a membrane filter (pore size 0.45 μm, hydrophilic) to obtain a solid. The obtained individual was washed with water and dried under reduced pressure at 80 ° C. for 10 hours to obtain a hydrogen polysilsesquioxane polymer (1).
A part of the hydrogen polysilsesquioxane (1) thus obtained was subjected to SEM observation.

(Preparation of silicon oxide)
After 1.5 g of the above hydrogen silsesquioxane (1) is placed on an SSA-S grade alumina boat, the boat is set in a vacuum purge type tube furnace KTF43N1-VPS (manufactured by Koyo Thermo System) and heat-treated. As a condition, under an argon gas atmosphere (high-purity argon gas 99.999%), while supplying argon gas at a flow rate of 250 ml / min, the temperature is raised at a rate of 4 ° C./min, and heat treatment is performed at 800 ° C. for 1 hour. By doing so, a silicon oxide was obtained.
Next, the obtained silicon oxide was crushed and pulverized in a mortar for 5 minutes, and classified using a stainless steel sieve having an opening of 32 μm to obtain powdery granular silicon oxide (1).
A part of the silicon oxide (1) thus obtained was subjected to SEM observation and particle size distribution measurement.

(Creation of negative electrode body)
0.8 g of the silicon oxide (1) and 0.1 g of acetylene black were added to 5 g of a 2 wt% aqueous solution of carboxymethyl cellulose, mixed in a flask for 15 minutes using a stirrer, and then the solid content concentration was 15. Distilled water was added so as to be in% by weight, and the mixture was further stirred for 15 minutes to prepare a slurry-like composition. This slurry-like composition was transferred to a thin film swirl type high-speed mixer (Fillmix 40-40 type) manufactured by Plymix, and stirred and dispersed at a rotation speed of 20 m / s for 30 seconds. The slurry after the dispersion treatment was coated on a copper foil roll with a thickness of 200 μm by a doctor blade method.
After coating, it was dried on a hot plate at 80 ° C. for 90 minutes. After drying, the negative electrode sheet was pressed with a 2t small precision roll press (manufactured by Thunk Metal Co., Ltd.). After pressing, the electrodes were punched out with an electrode punching punch HSNG-EP having a diameter of 14.50 mm, and dried under reduced pressure at 80 ° C. in a glass tube oven GTO-200 (SIBATA) for 16 hours to prepare a negative electrode body.

(Manufacturing and evaluation of lithium-ion secondary batteries)
A 2032 type coin battery having the structure shown in FIG. 7 was created. Ethylene carbonate and diethyl carbonate 1: in which the negative electrode body is used as the negative electrode 1, metallic lithium is used as the counter electrode 3, a microporous polypropylene film is used as the separator 2, and LiPF ₆ is dissolved at a ratio of 1 mol / L as the electrolytic solution. 1 (Volume ratio) A mixed solvent to which 5% by weight of fluoroethylene carbonate was added was used.
Next, the battery characteristics of the lithium ion secondary battery were evaluated by the method described above.

[Example 2]
In this example, first, hydrogen polysilsesquioxane was synthesized using only polyacrylic acid as a phase separation inducer without adding a substance (ethanol) that suppresses hydrolysis and polycondensation reaction. The synthesis procedure is as follows.

In the synthesis of hydrogen polysilsesquioxane in Example 1, hydrogen polysilsesquioxane (2) was prepared in the same manner except that ethanol was not added at all and the amount of pure water was 20 g.
Next, the silicon oxide (2) was obtained by heat-treating the hydrogen polysilcesquioxane (2) in the same manner as in Example 1, and a part thereof was subjected to SEM observation.

[Comparative Example 1]
In Comparative Example 1, hydrogen polysilsesquioxane was synthesized according to a conventional method without adding a substance (ethanol) that suppresses hydrolysis and polycondensation reaction and a phase separation inducer (polyacrylic acid) at all. The synthesis procedure is as follows.

7.20 g (120.12 mmol) of acetic acid and 1188.0 g of pure water were charged in a 3 L separable flask, and 225 g (1369.66 mmol) of triethoxysilane (Tokyo Kasei) was added dropwise at 25 ° C. under stirring. After completion of the dropping, a hydrolysis reaction and a condensation reaction were carried out at 25 ° C. for 2 hours with stirring.
After the reaction time had elapsed, the reaction product was filtered through a membrane filter (pore size 0.45 μm, hydrophilic), and the solid was recovered. The obtained solid was dried under reduced pressure at 80 ° C. for 10 hours to obtain hydrogen polysilsesquioxane (3).
A part of the hydrogen polysilsesquioxane (3) thus obtained was subjected to SEM observation.

Next, the silicon oxide (3) was obtained by heat-treating the hydrogen polysilcesquioxane (3) in the same manner as in Example 1, and a part thereof was subjected to SEM observation and particle size distribution measurement.
Further, a negative electrode active material was produced by using a silicon oxide (3) according to Example 1, and a negative electrode and a lithium ion secondary battery were produced using the negative electrode active material. The battery characteristics of the produced lithium-ion secondary battery were evaluated by the above-mentioned charge / discharge cycle test.

[Comparative Example 2]
In Comparative Example 2, first, hydrogen polysilsesquioxane was synthesized by using only ethanol as a substance that suppresses hydrolysis and polycondensation reaction without adding a phase separation inducer (polyacrylic acid) at all. The synthesis procedure is as follows.

In a 100 mL beaker, 0.02 g of acetic acid, 15 g of pure water, and 5 g of ethanol were charged. 5 g of triethoxysilane was added to the obtained solution, the mixture was stirred for 1 minute, placed in an oven together with the beaker, and heated at 80 ° C. for 1 hour. The obtained jelly-like mass was further heated for 10 hours to evaporate the solvent to obtain hydrogen polysilsesquioxane (4).
The hydrogen polysilsesquioxane (4) thus obtained was coarsely pulverized in a mortar. The obtained pulverized product was heat-treated according to the procedure described in Example 1 to obtain a silicon oxide (4). The silicon oxide (4) thus obtained was subjected to the above SEM observation.
The hydrogen polysilsesquioxane (4) before the heat treatment and the silicon oxide (4) obtained by the heat treatment were observed with the naked eye, and photographs of their appearance were obtained.

[result]
(Comparison of shapes of hydrogen polysilsesquioxane and silicon oxide)
The SEM photographs of the hydrogen polysilsesquioxane (1) and the silicon oxide (1) synthesized in Example 1 are shown in FIG. In addition, an SEM photograph of the hydrogen polysilsesquioxane (2) synthesized in Example 2 is shown in FIG.
Further, an SEM photograph of the hydrogen polysilsesquioxane (3) synthesized in Comparative Example 1 is shown in FIG. 3, and the hydrogen polysilsesquioxane (4) and the silicon oxide (4) obtained in Comparative Example 2 are usually obtained. A photograph and an SEM photograph of the silicon oxide (4) are shown in FIG.

In FIG. 1, the left column is an SEM photograph of the heat-treated hydrogen polysilcesquioxane (1), and the right column is an SEM photograph of the heat-treated silicon oxide. In each row, the upper is 2,500 times and the lower is 1,000 times.
As shown in the SEM photograph in the left column of FIG. 1, the obtained hydrogen was obtained in Example 1 in which ethanol (a substance that suppresses hydrolysis and polycondensation reaction) was added in addition to polyacrylic acid (phase separation inducer). Polysilsesquioxane (1) had the morphology of spherical fine particles with high sphericity. Further, as shown in the SEM photograph in the right column of FIG. 1, the morphology of the spherical particles having high sphericity was maintained even when the silicon oxide was formed by the heat treatment.

Further, as shown in FIG. 2, also in Example 2 in which only polyacrylic acid was used as a phase separation inducer without adding a substance that suppresses hydrolysis and polycondensation reaction such as ethanol, the obtained hydrogen polysilsesqui was obtained. In oxane (2), although some particles were agglomerated with each other, the individual particles had a substantially spherical morphology.
In addition, the hydrogen polysilsesquioxane (1) of Example 1 to which ethanol was added (SEM photograph in the left column of FIG. 1) was compared with the particles of Example 2 (FIG. 2) to which ethanol was not added. There was a tendency for the aggregation of ethanol to be more suppressed.

On the other hand, in Comparative Example 1 to which no phase separation inducer such as polyacrylic acid was added, as shown in FIG. 3, the obtained silicon oxide (3) had remarkably amorphous and non-spherical fine particles. It had an aggregated morphology.

Further, as shown in FIG. 4, even in Comparative Example 2 in which ethanol was added as a substance for suppressing water decomposition and polycondensation reaction but no phase separation inducer such as polyacrylic acid was added, the spherical hydrogen polysiene was added. Lucesquioxane fine particles could not be obtained.
The photograph in the left column in FIG. 4 is a photograph of the state of hydrogen polysilcesquioxane (4) which has not been heat-treated. Hydrogen polysilsesquioxane (4) had the form of a relatively large, amorphous and lumpy transparent gel, as can be seen with the naked eye. Further, the photographs in the right column of FIG. 4 are normal photographs (upper side) and SEM photographs (lower side) of the silicon oxide (4) obtained by heat-treating the elementary polysilsesquioxane (4). As can be seen from these photographs, the silicon oxide (4) has almost the same shape as the hydrogen polysilsesquioxane (4) before the heat treatment, and is amorphous and irregular in size. It was in morphology.

As described above, when synthesizing hydrogen polysilsesquioxane by hydrolysis and polycondensation of a predetermined silicon compound, a phase separation inducer such as a water-soluble polymer such as polyacrylic acid is contained in the reaction system. This demonstrated that spherical hydrogen polysilsesquioxane can be obtained by inducing phase separation. Further, by adding a substance that suppresses hydrolysis and polycondensation reaction such as ethanol in addition to the phase separation inducer, spherical hydrogen polysilsesquioxane fine particles having higher sphericity can be obtained, and further, the particles can be obtained from each other. It was demonstrated that the aggregation of ethanol can also be suppressed.

(Particle size distribution / particle size / BET specific surface area)
Next, FIG. 5 shows the results of particle size distribution measurement for the silicon oxides (1) and (3) obtained in Example 1 and Comparative Example 1, respectively.
Further, the volume-based cumulative 50% particle diameter D50 and the BET specific surface area measured for these silicon oxides (1) and (3) are shown in Table 1 below.

As shown in FIG. 5, the particle size distribution of hydrogen polysilsesquioxane (1) of Example 1 in which polyacrylic acid was added as a phase separation inducer and ethanol was added as a substance that suppresses hydrolysis and polycondensation was phase-separated. Compared to Comparative Example 1 in which hydrogen polysilsesquioxane was synthesized under almost the same conditions except that the inducer was not contained, the peak of the particle size distribution was shifted to the smaller one.

As for the volume-based cumulative 50% particle diameter D (50), as shown in Table 1, the value of Comparative Example 1 is 10.37 μm, whereas the value of Example 1 is 3.1 μm, which is smaller. It was a value.
Further, as shown in Table 1, the BET specific surface area of the silicon oxide is 3.5 m ² / g in Comparative Example 1, whereas it is 3.1 m ² / g in Example 1, which is a relatively small value. showed that. That is, according to the silicon oxide fine particles according to the present invention, the specific surface area can be made smaller with respect to the particle size. Further, according to the silicon oxide fine particles of the present invention, the specific surface area can be made smaller than the particle size. Therefore, when the silicon oxide fine particles are used as the negative electrode active material, the cloning efficiency due to the formation of SEI The decrease can be suppressed.

As described above, the hydrogen polysilsesquioxane fine particles according to the present invention produced by adding the phase separation inducer have constant properties in terms of particle size distribution, volume-based cumulative 50% particle size, BET specific surface area, and the like. Indicated.

(Negative electrode properties and battery characteristics test)
Next, the results of the cycle test of the lithium ion secondary batteries produced in Example 1 and Comparative Example 1 are shown in FIG.
Further, Table 2 shows the properties of the negative electrodes produced in Example 1 and Comparative Example 1 and the results of the cycle test.

As shown in Table 2, the electrode densities of the negative electrodes are 0.84 g / cm ^{3 in Comparative Example 1 and 1.08 g / cm 3 in} Example 1, which are larger values in Example 1 than in Comparative Example 1. showed that. That is, it was shown that the electrode density can be increased by using the spherical silicon oxide fine particles derived from the spherical hydrogen polysilsesquioxane fine particles according to the present invention. As described above, according to the spherical silicon oxide fine particles of the present invention, the electrode density can be increased, and as a result, the capacity of the secondary battery can be increased.
Further, regarding the results of the sackle test of the produced lithium ion secondary battery, as shown in Table 2 and FIG. 6, the initial charge / discharge efficiency is 42% in Comparative Example 1, whereas the initial charge / discharge efficiency is 42% in Example 1. The discharge efficiency was 44%. Therefore, it has been clarified that a high initial capacity can be realized by using the spherical silicon oxide fine particles according to the present invention as the negative electrode active material.
Although the capacity retention rate of Example 1 was slightly inferior to that of Comparative Example 1, it was not at a level that could not withstand practical use.

As described above, according to the present invention, it has been shown that hydrogen polysilsesquioxane, which is useful for various material applications including negative electrode active materials, can be provided in the form of spherical fine particles, which has been difficult to realize so far. .. Furthermore, according to the present invention, it has been shown that it is possible to provide a negative electrode active material capable of achieving a particularly high capacity while maintaining various battery characteristics of a secondary battery.

The present invention can be applied as a negative electrode active material of a secondary battery, a negative electrode, and a secondary battery. Therefore, the present invention has high industrial applicability in the field of chemistry for manufacturing negative electrode materials, the field of electrical and electronic equipment such as secondary batteries and various electronic devices, and the field of vehicles such as hybrid automobiles.

1: Negative electrode material 2: Separator 3: Lithium counter electrode 10: Coin type lithium ion battery

Claims (36)

Consists of substantially spherical primary particles,
In the volume-based particle size distribution obtained by the laser diffraction / scattering method, the volume average particle diameter D50 at which the cumulative distribution value is 50% is less than 1 mm.
In a solution system in which a silicon compound represented by the following general formula (VI) is present, a hydrogen polysil produced by hydrolyzing and polycondensing the silicon compound and at the same time promoting phase separation of the solution system. Sesquioxane fine particles :
HSi (R) ₃ ... (VI)
(In the formula, R is a hydrolyzable functional group, and R may be the same as or different from each other.) The hydrogen polysilsesquioxane fine particles according to claim 1, wherein the volume average particle diameter D50 is 80 μm or less. The hydrogen polysilsesquioxane fine particles according to claim 1 or 2, wherein the volume average particle diameter D50 is a predetermined value in the range of 100 nm to 50 μm. The hydrogen polysilsesquioxane fine particles according to any one of claims 1 to 3, wherein the volume average particle diameter D50 is a predetermined value in the range of 500 nm to 10 μm. The hydrogen polysilsesquioxane fine particles according to any one of claims 1 to 4, which include hydrogen polysilsesquioxane represented by the following general formula (I).

In the formula, R ¹ , R ² , R ³ and R ⁴ are independently derived from hydrogen, substituted or unsubstituted alkyl having 1 to 45 carbon atoms, substituted or unsubstituted aryl, and substituted or unsubstituted aryl alkyl, respectively. A group selected from the group consisting of an alkyl having 1 to 45 carbon atoms, any hydrogen may be replaced with a halogen, and any -CH _2- is -O-, -CH = CH-,. In the alkylene in the substituted or unsubstituted arylalkyl group, any hydrogen may be replaced with a halogen, and any -CH _2- may be replaced with a cycloalkylene, ^a cycloalkenylene or -SiR _12- . , -O-, -CH = CH-, cycloalkylene, cycloalkenylene or -SiR ¹² _- may be replaced.
n represents an integer of 1 or more. The hydrogen polysilsesquioxane fine particles according to any one of claims 1 to 5, which include hydrogen polysilsesquioxane represented by the following general formula (II):

In the formula, R ¹ , R ² , R ³ and R ⁴ are independently derived from hydrogen, substituted or unsubstituted alkyl having 1 to 45 carbon atoms, substituted or unsubstituted aryl, and substituted or unsubstituted aryl alkyl, respectively. A group selected from the group consisting of an alkyl having 1 to 45 carbon atoms, any hydrogen may be replaced with a halogen, and any -CH _2- is -O-, -CH = CH-,. It may be replaced with cycloalkylene, cycloalkenylene, or -SiR 12-, and in the alkylene in the substituted or unsubstituted arylalkyl group, any hydrogen may be substituted with halogen, and ^any _{-CH 2-} May be replaced with -O-, -CH ₌ CH-, cycloalkylene, cycloalkenylene, or -SiR ^12- .
n represents an integer of 1 or more. The hydrogen polysilsesquioxane fine particles according to any one of claims 1 to 6, which include hydrogen polysilsesquioxane represented by any one of the following general formulas (III) to (V):

The method for producing hydrogen polysilsesquioxane fine particles according to any one of claims 1 to 7, which comprises the following step (p):
(P) In a solution system in which a silicon compound represented by the following general formula (VI) is present, the silicon compound is hydrolyzed and polycondensed, and at the same time, phase separation of the solution system is promoted to promote the phase separation of the solution system. Producing oxane fine particles,
HSi (R) ₃ ... (VI)
(In the formula, R is a hydrolyzable functional group, and R may be the same as or different from each other). In the general formula (VI), R is halogen, hydrogen, substituted or unsubstituted alkoxy having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy having 6 to 20 carbon atoms, and substituted or substituted with 7 to 30 carbon atoms. Substituentally substituted or unsubstituted alkoxys having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy having 6 to 20 carbon atoms, and substituted or unsubstituted groups having 7 to 30 carbon atoms, which are groups selected from unsubstituted arylalkoxys. The method of claim 8, wherein in the substituted arylalkoxy, any hydrogen may be substituted with halogen and R may be the same or different from each other. The method according to claim 8 or 9, wherein the solution system comprises a phase separation inducer that promotes phase separation of the solution system. The method according to claim 10, wherein the phase separation inducer is a hydrogen-bonding substance. The method according to claim 10 or 11, wherein the phase separation inducer is a water-soluble polymer. The method according to any one of claims 10 to 12, wherein the phase separation inducer is polyacrylic acid or a salt thereof. The method according to any one of claims 10 to 13, wherein the solution system further contains a substance that suppresses hydrolysis and polycondensation of the silicon compound. The method according to claim 14, wherein the substance that suppresses hydrolysis and polycondensation of the silicon compound is a polar solvent. 15. The method of claim 15, wherein the polar solvent is at least one selected from the group consisting of alcohol, acetone, acetonitrile, N-methyl-2-pyrrolidone, N, N-dimethylformamide, and dimethyl sulfoxide. 15. The method of claim 15, wherein the polar solvent is alcohol. The method according to any one of claims 10 to 17, wherein the step (p) is carried out by adding the silicon compound to a solution containing at least a phase separation inducer and water in advance. The method according to claim 18, wherein the solution containing at least the phase separation inducer and water in advance further comprises a catalyst for promoting hydrolysis and polycondensation of the silicon compound. 18. The method of claim 18 or 19, further comprising the following step (p') prior to step (p):
(P') To prepare a solution containing at least the phase separation inducer and water in advance. The compound according to claim 8 to 20, wherein the silicon compound is a compound selected from trihalogenated silane, dihalogenated silane, trialkoxysilane, dialkoxysilane, aryloxysilane, aryloxysilane, and aryloxyalkoxysilane. The method according to any one. The method according to any one of claims 8 to 21, wherein the silicon compound is trihalogenated silane or trialkoxysilane. The method according to any one of claims 8 to 22, further comprising the following step (q).
(Q) Washing and / or drying the hydrogen polysilsesquioxane fine particles produced in step (p) with a predetermined solvent. A method for producing silicon oxide fine particles, which comprises the following step (r):
(R) Producing silicon oxide fine particles by heat-treating the hydrogen polysilcesquioxane fine particles according to any one of claims 1 to 7 in a non-oxidizing gas atmosphere, wherein the silicon oxidation . The fine particles are composed of substantially spherical primary particles and have a volume average particle diameter D50 of less than 1 mm .
The volume average particle size D50 is assumed to be a volume average particle size having a cumulative distribution value of 50% in the volume reference particle size distribution acquired by the laser diffraction / scattering method. The method according to claim 24, wherein the silicon oxide fine particles have an elemental composition represented by the general formula SiOxHy (1 <x <1.8, 0.01 <y <0.4). The method according to claim 24 or 25, wherein the non-oxidizing gas atmosphere is an inert gas. The method according to any one of claims 24 to 26, wherein in the step (r), the hydrogen polysilsesquioxane fine particles are heat-treated at a predetermined temperature in the range of 600 ° C. to 900 ° C. The method according to any one of claims 24 to 27, further comprising the following step (p) prior to step (r):
(P) In a solution system containing a silicon compound represented by the following general formula (VI), the silicon compound is hydrolyzed and polycondensed, and phase separation of the solution system is promoted to obtain the hydrogen polysilsesquioxane fine particles. To generate,
HSi (R) ₃ ... (VI)
(In the formula, R is a hydrolyzable functional group, and R may be the same as or different from each other). It is produced by heat-treating the hydrogen polysilcesquioxane fine particles according to any one of claims 1 to 7 in a non-oxidizing gas atmosphere, and the following conditions (x), (y) and (z) are used. Silicon oxide fine particles that satisfy:
(X) The volume average particle diameter D50 at which the cumulative distribution value is 50% in the volume-based particle size distribution obtained by the laser diffraction / scattering method is in the range of nanometers or micrometers;
(Y) Consists of substantially spherical primary particles ; and (z) has an elemental composition represented by the general formula SiOxHy (1 <x <1.8, 0.01 <y <0.4). The silicon oxide fine particles according to claim 29, wherein the volume average particle diameter D50 is 80 μm or less. The silicon oxide fine particles according to claim 29 or 30, wherein the volume average particle diameter D50 is a predetermined value in the range of 100 nm to 50 μm. The silicon oxide fine particles according to any one of claims 29 to 31, wherein the volume average particle diameter D50 is a predetermined value in the range of 500 nm to 10 μm. A negative electrode active material for a secondary battery, which comprises the silicon oxide fine particles according to any one of claims 29 to 32. A negative electrode for a secondary battery, which comprises the negative electrode active material for a secondary battery according to claim 33. A secondary battery comprising the negative electrode for a secondary battery according to claim 34. The secondary battery according to claim 35, which is a lithium ion secondary battery.

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