JP2015162295A - Silicon oxycarbide ceramic, method for manufacturing the same, silicon oxycarbide composite material, and nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon oxycarbide ceramic which exhibits a superior discharge capacity and cycle characteristics when used as a negative electrode active material for nonaqueous electrolyte secondary batteries.SOLUTION: A method for manufacturing a silicon oxycarbide ceramic comprises: preparing a mixture solution by mixing a silicon-containing organic compound in a dispersion prepared by dispersing a carbon-containing compound in a solvent; subjecting the mixture solution to a polymerization process at a temperature between T-10(°C) and T(°C) where T(°C) represents the boiling point of the mixture solution; primarily calcining the resultant product at a temperature of more than 200°C and 800°C or less, thereby pulverizing and classifying the calcined product to prepare primarily calcined powder; and secondarily calcining the primarily calcined powder under a temperature condition of more than 800°C and 1200°C or less.

Description

  The present invention relates to a silicon oxycarbide ceramic, a manufacturing method thereof, a silicon oxycarbide composite material, and a nonaqueous electrolyte secondary battery.

Lithium secondary batteries are high-power, high-capacity secondary batteries that are often used for portable devices such as mobile phones, personal computers, PDAs (personal information terminals), standby power supplies, and drive power supplies for vehicles. Demand is expected to be even higher.
In these applications, there is a strong demand for smaller size, lighter weight, and higher capacity, and in order to meet those demands, various parts and materials of secondary batteries are actively being improved. The development of negative electrode active materials is becoming increasingly important.

Currently, carbon (graphite) is the mainstream of the negative electrode active material, and a discharge capacity of about 350 to 360 mAh / g and a value close to the theoretical capacity of graphite (372 mAh / g) have been put into practical use. It is impossible to exceed the theoretical capacity of graphite.
Metallic silicon, on the other hand, is expected to be a negative electrode active material that can be substituted for graphite because its theoretical capacity is an extremely large 4200 mAh / g. There was a technical problem.

  Therefore, for the purpose of improving the cycle characteristics of the battery while increasing the discharge capacity, it has been proposed to make silicon finer, nanowired, hollowed, etc., and to mix graphite powder with silicon powder (for example, non- Patent Document 1, Non-Patent Document 2, Patent Document 1 and the like), and a negative electrode active material for a non-aqueous electrolyte secondary battery are required to exhibit even better performance.

Journal of power source, 195 (2010) p.1720-1725. Dalton trans, (2008) p.5424-5431

Japanese Patent No. 3268770

  Under such circumstances, silicon oxycarbide (SiOC) ceramics, which is a silicon compound, has been studied as a negative electrode active material for nonaqueous electrolyte secondary batteries. However, the discharge capacity is low and practically sufficient performance is achieved. Discharge capacity when used as a negative electrode active material for non-aqueous electrolyte secondary batteries because it is difficult to put into practical use due to the fact that it cannot be demonstrated or because the raw material, catalyst or manufacturing method is special and the manufacturing cost is high. In addition, silicon oxycarbide ceramics that are excellent in cycle characteristics (cycle retention rate) and that can be industrially mass-produced simply and at low cost have been demanded.

  Accordingly, the present invention provides silicon oxycarbide ceramics that exhibit excellent discharge capacity and cycle characteristics (cycle retention rate) when used as a negative electrode active material for a non-aqueous electrolyte secondary battery. Provided is a method capable of industrially mass-producing ceramics easily and at low cost, and further provides a silicon oxycarbide ceramic composite material using the silicon oxycarbide ceramic and a nonaqueous electrolyte using the silicon oxycarbide ceramic as a negative electrode active material The object is to provide a secondary battery.

As a result of intensive studies by the present inventors, a silicon-containing organic compound is mixed with a dispersion in which a carbon-containing compound is dispersed in a solvent to prepare a mixture, and then the boiling point of the mixture is T _b (° C.). In addition, after the polymerization treatment was performed at a temperature between T _b −10 (° C.) and T _b (° C.), the obtained product was subjected to primary firing at a temperature exceeding 200 ° C. and not more than 800 ° C. Classifying the primary fired powder to produce silicon oxycarbide ceramic by subjecting the primary fired powder to secondary firing under a temperature condition of 800 ° C. to 1200 ° C. The present inventors have found that the problem can be solved, and have completed the present invention based on this finding.

That is, the present invention
(1) Silicon oxycarbide ceramics,
A silicon-containing organic compound is mixed with a dispersion obtained by dispersing a carbon-containing compound in a solvent to prepare a mixed solution,
Next, when the boiling point of the liquid mixture is T _b (° C.), after performing the polymerization treatment at a temperature between T _b −10 (° C.) and T _b (° C.),
The obtained product is subjected to primary firing at a temperature exceeding 200 ° C. and not more than 800 ° C., and pulverized and classified to produce a primary fired powder,
Silicon oxycarbide ceramics, wherein the primary fired powder is subjected to secondary firing under a temperature condition of more than 800 ° C. and 1200 ° C. or less,
(2) A method for producing silicon oxycarbide ceramics,
A silicon-containing organic compound is mixed with a dispersion obtained by dispersing a carbon-containing compound in a solvent to prepare a mixed solution,
Then the boiling point of the mixture is taken as T _b, after polymerization treatment at a temperature between T from T b _-10 ° C. _b,
The obtained product is subjected to primary firing at a temperature exceeding 200 ° C. and not more than 800 ° C., and pulverized and classified to produce a primary fired powder,
A method for producing silicon oxycarbide ceramics, wherein the primary firing powder is subjected to secondary firing under a temperature condition of more than 800 ° C. and 1200 ° C. or less,
(3) The method for producing silicon oxycarbide ceramics according to (2), wherein the carbon-containing compound is a phenol resin having two or more OH groups,
(4) The method for producing silicon oxycarbide ceramics according to (2) or (3), wherein the solvent is an oxygen-containing organic compound,
(5) The method for producing silicon oxycarbide ceramics according to any one of (2) to (4), wherein the silicon-containing organic compound is an alkoxysilane compound having two or more alkoxy groups,
(6) A carbon coating containing silicon oxycarbide ceramics on the surface of silicon oxycarbide ceramics according to (1) above or silicon oxycarbide ceramics obtained by the production method according to any of (2) to (5) above A silicon oxycarbide ceramic composite material, characterized in that
(7) A silicon oxycarbide ceramic described in (1) above or a silicon oxycarbide ceramic obtained by the manufacturing method described in any of (2) to (5) above is included as a negative electrode active material. A water electrolyte secondary battery is provided.
Hereinafter, silicon oxycarbide ceramics will be appropriately referred to as SiOC ceramics, and silicon oxycarbide ceramic composite materials will be appropriately referred to as SiOC ceramic composite materials.

  According to the present invention, when used as a negative electrode active material for a non-aqueous electrolyte secondary battery, silicon oxycarbide ceramics exhibiting excellent discharge capacity and cycle characteristics (cycle retention rate) can be provided, and Provided is a method capable of industrially mass-producing carbide ceramics easily and at low cost, and further provides a silicon oxycarbide ceramic composite material using the silicon oxycarbide ceramic and a non-aqueous solution using the silicon oxycarbide ceramic as a negative electrode active material. An electrolyte secondary battery can be provided.

It is sectional drawing for demonstrating the structure of the battery produced in the Example of this invention.

  First, the SiOC ceramic of the present invention will be described.

The SiOC ceramic of the present invention is
A silicon-containing organic compound is mixed with a dispersion obtained by dispersing a carbon-containing compound in a solvent to prepare a mixed solution,
Next, when the boiling point of the liquid mixture is T _b (° C.), after performing the polymerization treatment at a temperature between T _b −10 (° C.) and T _b (° C.),
The obtained product is subjected to primary firing at a temperature exceeding 200 ° C. and not more than 800 ° C., and pulverized and classified to produce a primary fired powder,
The primary fired powder is obtained by secondary firing under a temperature condition of more than 800 ° C. and 1200 ° C. or less.

  The SiOC ceramic of the present invention is defined by its production method, and the details of the production method are as described in the description of the invention of the production method of the SiOC ceramic of the present invention described later.

SiOC ceramics of the present invention, the tap density when the average particle diameter _{D 50} was 1000 times tapping when it is 5~30μm ^is, preferably has a 0.80g / cm ³ ~1.50g / cm 3 , preferably it has a ^{0.85g / cm 3 ~1.50g / cm 3} , it is more preferable at ^{0.90g / cm 3 ~1.50g / cm 3} .

When the tap density is less than 0.80 g / cm ³ , the battery capacity per unit volume (electrode density) decreases, and when it exceeds 1.50 g / cm ³ , the cycle characteristics deteriorate.
The SiOC ceramic of the present invention exhibits excellent battery capacity and excellent cycle characteristics when used as a negative electrode active material of a non-aqueous electrolyte secondary battery because the tap density is within the above range. To extend the life of the battery.
The tap density can be easily controlled within a desired range by appropriately adjusting the particle size, for example.

In addition, in this application document, the tap density when tapping 1000 times means a value measured according to JIS Z2512: 2012, specifically, a tap density measuring device tap manufactured by Seishin Corporation. It means the density when tapping 1000 times using a denser (KYT-5000k).
The measurement method of the average particle diameter D ₅₀ are as described below.

SiOC ceramics of the present invention is preferably one has a BET specific surface area of 0.5m ² / g~50m ² / ^g, more preferably those which are ^{1m 2 / g~45m 2 / g,} 3m 2 / g~40m More preferred is ² / g.

When the BET specific surface area exceeds 50 m ² / g, the amount of the binder required at the time of producing the electrode of the secondary battery is increased and the amount of the active material in the unit electrode volume is decreased, so that the battery capacity is easily lowered. Or, by increasing the specific surface area, the surface activity of the particles is increased, and when used as a negative electrode active material for a non-aqueous electrolyte secondary battery, the electrolytic solution is decomposed and the Coulomb efficiency and cycle characteristics are likely to deteriorate. Become.
When the BET specific surface area is less than 0.5 m ² / g, it is difficult to exhibit desired characteristics when used as a negative electrode active material for a non-aqueous electrolyte secondary battery.
The BET specific surface area can be easily controlled within a desired range, for example, by adjusting the firing temperature or increasing the particle size.

  In the present application documents, the BET specific surface area means a value measured according to JIS Z8830, and specifically, a nitrogen adsorption isotherm using Shimadzu Corporation fully automatic surface area measuring device Gemini V. Means a value calculated by the BET multipoint method at 6 points in the range of relative pressure of 0.05 to 0.2.

  The SiOC ceramic of the present invention is usually particulate.

The SiOC ceramic of the present invention preferably has a 50% particle size D ₅₀ in the volume-based cumulative particle size distribution of 1 to 30 μm, more preferably 2 to 28 μm, and more preferably 3 to 25 μm. Is more preferable, and what is 5-25 micrometers is still more preferable.

When the particle diameter D ₅₀ is more than 30 μm, the electrode density is difficult to increase and the battery capacity per volume may be reduced. When the particle diameter D ₅₀ is less than 1 μm, the electrolytic solution is decomposed during charging and discharging. Side reactions such as are likely to occur.

Note that in the present application, the particle diameter _{D 50} is, JIS Z8825-1: means the value measured according to 2001, specifically, pole miniature spatula 2 cups a measurement sample, and a non-ionic 2 drops of surfactant (Triton-X) added to 50 ml of water and ultrasonically dispersed for 3 minutes were used as measurement samples, and a laser diffraction particle size distribution analyzer (SALD2000 manufactured by Shimadzu Corporation) was used. Means the value to be measured.

SiOC ceramics of the present invention has a predetermined tap density, by those having a predetermined BET specific surface area and particle diameter D _50, readily exhibits excellent discharge capacity and cycle characteristics (the cycle retention ratio) be able to.

The SiOC ceramic of the present invention preferably contains 10 to 50% Si atoms, more preferably contains 12 to 48%, more preferably contains 15 to 45%, and more preferably contains O atoms. 10 to 50%, preferably 12 to 48%, more preferably 15 to 45%, more preferably 20 to 70% carbon atoms, and preferably 22 to 69%. %, More preferably 25 to 65%.
When the SiOC ceramic of the present invention contains Si atoms, O atoms and carbon atoms in specific ratios, an excellent discharge capacity can be easily exhibited.
In the present application documents, the atomic ratio of Si atom, O atom, and carbon atom means a value specified by the method described in Solid state ionics, 225 (2012) p.522-526, specifically, This means a value calculated by identifying the carbon atom and oxygen atom amounts with the carbon analyzer (LECO, C-200) and N / O analyzer (LECO, TC-436) and setting the remaining amount as Si atoms. .

The SiOC ceramic of the present invention can be suitably produced by the method for producing the SiOC ceramic of the present invention described later.
Since the SiOC ceramic of the present invention is obtained by mixing and polymerizing a carbon-containing compound and a silicon-containing organic compound in a specific order, followed by a firing treatment, the carbon-containing compound and the silicon-containing organic compound that are raw materials As a result, when used as a negative electrode active material for non-aqueous electrolyte secondary batteries, it is considered that excellent discharge capacity and cycle characteristics (cycle retention rate) can be exhibited. It is done.

  ADVANTAGE OF THE INVENTION According to this invention, when it uses as a negative electrode active material for nonaqueous electrolyte secondary batteries, the SiOC ceramics which exhibit the outstanding discharge capacity and cycling characteristics (cycle maintenance factor) can be provided.

Next, the manufacturing method of the SiOC ceramic of this invention is demonstrated.
In the method for producing a SiOC ceramic of the present invention, a silicon-containing organic compound is mixed with a dispersion obtained by dispersing a carbon-containing compound in a solvent to prepare a mixed solution,
Then the boiling point of the mixture is taken as T _b, after polymerization treatment at a temperature between T from T b _-10 ° C. _b,
The obtained product is subjected to primary firing at a temperature exceeding 200 ° C. and not more than 800 ° C., and pulverized and classified to produce a primary fired powder,
The primary firing powder is subjected to secondary firing under a temperature condition of over 800 ° C. and 1200 ° C. or less.

  In the method for producing SiOC ceramics of the present invention, examples of the carbon-containing compound include resins having an OH group, and the resin having an OH group is preferably a resin having two or more OH groups, The resin having two or more OH groups is more preferably at least one selected from phenolic resins such as resol type phenolic resin or novolac type phenolic resin, and furan resin, such as resol type phenolic resin or novolac type phenolic resin, etc. More preferred is a phenol resin.

  In the method for producing SiOC ceramics of the present invention, when the carbon-containing compound is a resin having an OH group, the weight average molecular weight Mw is preferably 200 to 20000, more preferably 500 to 15000, and 1000 to More preferably, it is 3000.

  When the weight average molecular weight Mw is less than 200, the polymer is silicified by water generated by dehydration condensation between resins. Therefore, when the obtained SiOC ceramic is used as a negative electrode active material for a non-aqueous electrolyte secondary battery. The discharge capacity of the negative electrode material tends to decrease. When the said weight average molecular weight Mw exceeds 20000, it becomes difficult to melt | dissolve in a solvent and it becomes difficult to perform a polymerization reaction with a silicon-containing organic compound.

  In the method for producing SiOC ceramics of the present invention, the solvent for dispersing the carbon-containing compound is not particularly limited, but is preferably a solvent capable of dissolving the carbon-containing compound. Specifically, the oxygen-containing organic compound and the oxygen-containing compound are included. One or more types selected from nitrogen organic compounds can be mentioned, and examples of the oxygen-containing organic compound and nitrogen-containing organic compound include one or more types selected from various polar solvents and diols (excluding alkylene glycols having a molecular weight of 100 or more). Can be mentioned.

Examples of the polar solvent include one or more selected from methanol, ethanol, propanol, butanol, acetone, methyl ketone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, and the like.
Examples of the diol include one or more selected from ethylene glycol and the like.

  In the method for producing a SiOC ceramic of the present invention, the amount of the solvent used is preferably 10 to 1000 parts by mass, more preferably 50 to 750 parts by mass, and 100 to 500 parts by mass with respect to 100 parts by mass of the carbon-containing compound. Further preferred. When the usage-amount of the said solvent is less than 10 mass parts with respect to 100 mass parts of carbon containing compounds, since it is difficult to melt | dissolve a carbon containing compound etc., it may become difficult to superpose | polymerize uniformly. When the usage-amount of the said solvent exceeds 1000 mass parts with respect to 100 mass parts of carbon containing compounds, an excess solvent will increase and it will become high cost.

  In the method for producing a SiOC ceramic of the present invention, a dispersion in which a carbon-containing compound is dispersed in a solvent can be prepared by appropriately mixing the carbon-containing compound and the solvent.

In the method for producing a SiOC ceramic of the present invention, examples of the silicon-containing organic compound include siloxane (a silicon-containing organic compound having a —O—Si—O— structure as a main skeleton). An alkoxysilane compound having an alkoxy group is preferable. As an alkoxysilane compound having two or more alkoxy groups, a tetraalkoxysilane monomer or oligomer is preferable, and a tetramethoxysilane monomer, a tetraethoxysilane monomer, or a tetramethoxysilane oligomer is preferable. More preferably, it is at least one selected from tetraethoxysilane oligomers.
In the method for producing SiOC ceramics of the present invention, the silicon-containing organic compound preferably has a SiO ₂ equivalent of 28% by mass or more, more preferably 30% by mass or more, and 35% by mass or more. More preferred.

In the method for producing SiOC ceramics of the present invention, the mixing ratio of the silicon-containing organic compound and the carbon-containing compound is not particularly limited, but 200 to 2000 parts by mass of the silicon-containing organic compound is mixed with 100 parts by mass of the carbon-containing compound. It is preferable to mix 150 to 1500 parts by mass of the silicon-containing organic compound, and it is more preferable to mix 100 to 1000 parts by mass of the silicon-containing organic compound.
In the method for producing a SiOC ceramic of the present invention, when the mixing ratio of the silicon-containing organic compound and the carbon-containing compound is within the above range, the resulting SiOC ceramic is used as a negative electrode active material for a non-aqueous electrolyte secondary battery. It is possible to easily exhibit excellent discharge capacity and conductivity.

In the method for producing a SiOC ceramic of the present invention, when mixing a carbon-containing compound and a silicon-containing organic compound, the mixed atmosphere is preferably an inert atmosphere, and the inert atmosphere is a rare gas atmosphere such as a nitrogen atmosphere or an argon atmosphere. Can be mentioned.
The mixing is more preferably performed in a non-water atmosphere, and examples of the non-water atmosphere include a rare gas atmosphere such as a dehydrated nitrogen atmosphere and an argon atmosphere.
In the method for producing SiOC ceramics according to the present invention, if water is present during the mixing or the following polymerization operation, the silicification of the silicon-containing organic compound is likely to proceed, so that the obtained SiOC ceramics are used as a non-aqueous electrolyte secondary battery. When used as a negative electrode active material, the battery capacity tends to decrease and the battery characteristics tend to decrease.
The mixing can also be performed while circulating a solvent using an instrument equipped with a condenser.

In the method for producing SiOC ceramics according to the present invention, the mixing of the silicon-containing organic compound and the carbon-containing compound is preferably performed by adding the silicon-containing organic compound dropwise to a dispersion obtained by dispersing the carbon-containing compound in a solvent. In this case, it is preferable to prepare a mixed solution by dropping the silicon-containing organic compound while stirring the dispersion in which the carbon-containing compound is dispersed in the solvent.
The mixing of the silicon-containing organic compound and the carbon-containing compound is preferably performed with a stirrer so that the shear rate is 1 (1 / second) or more, and the shear rate is 10 (1 / second) or more. More preferably.
By stirring at the shear rate, uniform mixing can be performed more easily.

  In the method for producing SiOC ceramics of the present invention, a carbon-containing compound and a silicon-containing organic compound are mixed in a solvent by mixing a silicon-containing organic compound with a dispersion in which a carbon-containing compound is dispersed in a solvent to prepare a mixed solution. Compared with the case where a mixed solution is prepared by mixing at the same time, SiOC ceramics that can exhibit a high charge / discharge capacity when used as a negative electrode active material of a nonaqueous electrolyte secondary battery can be easily obtained.

In the method for producing SiOC ceramics according to the present invention, when a liquid mixture prepared by mixing a silicon-containing organic compound with a dispersion liquid in which a carbon-containing compound is dispersed in a solvent, the boiling point of the liquid mixture is T _b (° C.). In addition, the polymerization treatment is performed at a temperature between T _b −10 (° C.) and T _b (° C.).

The temperature at which the polymerization treatment is performed is a temperature between T _b −10 (° C.) and boiling point T _b (° C.), and a temperature between T _b −7 (° C.) and boiling point T _b (° C.). Is more preferable, and a temperature between T _b −5 (° C.) and boiling point T _b (° C.) is more preferable.

  In the method for producing SiOC ceramics of the present invention, a carbon-containing compound is prepared by subjecting a mixed solution prepared by mixing a silicon-containing organic compound to a dispersion obtained by dispersing a carbon-containing compound in a solvent to a polymerization treatment at the above temperature. In addition, the silicon-containing organic compound can be easily uniformly polymerized, and as a result, a polymer having a high yield can be obtained, and a calcined product having a high charge capacity can be obtained by further firing treatment.

Note that in the present application, the boiling point T _b of the liquid mixture, insert the thermocouple in the mixture, the temperature at which boiling is observed at normal pressure data logger (Graphtec Corporation, mid: logger, GC220) used Means the measured value.

In the method for producing SiOC ceramics according to the present invention, specifically, the temperature for performing the polymerization treatment is preferably 0 to 200 ° C, more preferably 10 to 175 ° C, and further preferably 20 to 150 ° C. .
When the said temperature is less than 0 degreeC, a polymerization rate becomes low and the yield (yield) of a product tends to fall.

In the method for producing a SiOC ceramic of the present invention, the polymerization treatment time is preferably 1 to 240 hours, more preferably 2 to 220 hours, and further preferably 3 to 200 hours.
If the polymerization treatment time is less than 1 hour, the yield (yield) of the resulting polymerized product (silicon oxycarbide ceramic precursor) tends to decrease, and if it exceeds 240 hours, the production cost increases.

In the method for producing SiOC ceramics of the present invention, the polymerization treatment is preferably performed in the presence of a polymerization catalyst, and examples of the polymerization catalyst include an acid catalyst and a base catalyst.
Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, phosphoric acid, and boric acid, organic sulfonic acids such as p-toluenesulfonic acid, and organic acids such as formic acid, acetic acid, propionic acid, and benzoic acid. One or more types selected from organic dicarboxylic acids such as monocarboxylic acids, oxalic acid, malonic acid, succinic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid can be mentioned.
Examples of the base catalyst include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, organic amines such as ammonia, monomethylamine and dimethylamine, and quaternary compounds such as tetramethylammonium hydroxide. One or more selected from ammonium salts can be mentioned.

  In the method for producing SiOC ceramics of the present invention, in consideration of operability and industrial stability, it is desirable to carry out a polymerization reaction under acidic conditions using an acid catalyst, and in particular, p-toluenesulfonic acid is used as the acid catalyst. It is preferable to carry out the polymerization reaction using at least one selected from malonic acid and fumaric acid.

  In the method for producing SiOC ceramics of the present invention, the mixing amount of the polymerization catalyst is preferably 0.1 to 50 parts by mass when the total amount of the silicon-containing organic compound and the carbon-containing compound is 100 parts by mass, The amount is more preferably 0.3 to 30 parts by mass, and further preferably 1 to 20 parts by mass.

  In the method for producing SiOC ceramics of the present invention, (1) when a tetraethoxysilane oligomer is used as the silicon-containing organic compound and a resol type phenol resin is used as the carbon-containing compound, it is estimated that the following polymerization reaction proceeds. . In the course of this reaction, it is presumed that the polymerization of the resol type phenol resins also proceeds in parallel.

  In the method for producing SiOC ceramics of the present invention, (2) when a tetraethoxysilane oligomer is used as the silicon-containing organic compound and a novolac type phenol resin is used as the carbon-containing compound, the following polymerization reaction is assumed to proceed. Is done. In the course of this reaction, it is presumed that the polymerization of novolac type phenol resins also proceeds in parallel.

  In this case, the reaction product obtained by the polymerization reaction of (1) tends to contain a residual SiO structure as the amount of carbon per SiO structure increases, and the reaction product obtained by the polymerization reaction of (2) In order to form a structure that surrounds the substrate with a benzene ring having carbon atoms, the dispersion of the SiO structure commensurate with conductivity and molecular weight is facilitated, and the resulting SiO ceramics was used as a negative electrode active material for non-aqueous secondary batteries. Sometimes it becomes easy to increase the capacity.

  In the method for producing SiOC ceramics of the present invention, it is preferable to remove the solvent after the polymerization treatment.

It is desirable to remove the solvent under vacuum or in an inert atmosphere.
The solvent removal is preferably performed while controlling the pressure within a predetermined range. The pressure at the time of solvent removal is preferably 0.01 to 600 torr, more preferably 0.1 to 550 torr, and further preferably 1 to 500 torr.
The solvent removal can be performed by controlling the ambient temperature to a certain temperature or higher, and the ambient temperature at the time of solvent removal is preferably 30 to 200 ° C, more preferably 50 to 200 ° C, and further 70 to 200 ° C. preferable. The atmospheric temperature can be controlled by appropriately heating or the like.
The removal time of the solvent is preferably 0.1 to 100 hours, more preferably 0.3 to 75 hours, and further preferably 0.5 to 50 hours.
When the heating temperature is less than 30 ° C., it is difficult to efficiently remove the solvent, and when a solvent is used during the polymerization reaction, it takes a long time to remove the solvent.

  By performing the solvent removal treatment in a reduced-pressure atmosphere such as a vacuum atmosphere, the solvent used in the polymerization reaction, side reaction products, and unreacted raw materials can be removed, and further the polymerization reaction can proceed.

  In the method for producing a SiOC ceramic of the present invention, the obtained product is subjected to primary firing at a temperature exceeding 200 ° C. and not higher than 800 ° C., and pulverized and classified to produce a primary fired powder.

  In the method for producing SiOC ceramics according to the present invention, it is preferable to appropriately perform a preliminary pulverization treatment before the firing treatment.

In the method for producing SiOC ceramics according to the present invention, when pre-pulverization is performed before the primary firing treatment of the polymerized product, it is preferable to perform pulverization until the maximum particle size is 1000 μm or less, and the maximum particle size is 750 μm or less. It is more preferable to pulverize until the maximum particle size is 500 μm or less.
The pulverization is preferably performed using a pulverizer selected from known mechanical pulverizers such as a hammer mill, a pin mill, a jet mill, a bevel impactor, a turbo mill, a knife hammer mill, a rotary cutter mill, and a roll crusher.
Further, classification may be performed using a classifier such as a wind type or a mechanical type.

  In the present application document, the maximum particle size means a particle size of 99% in terms of an integrated particle size in a volume-based integrated particle size distribution measured by a laser diffraction particle size distribution analyzer according to JIS Z8825-1: 2001. Specifically, the measurement sample was prepared by adding 2 cups of ultra-small spatula and 2 drops of nonionic surfactant (Triton-X) to 50 ml of water and ultrasonically dispersing for 3 minutes, The cumulative particle size in the volume-based cumulative particle size distribution measured using a laser diffraction particle size distribution analyzer (SALD2000 manufactured by Shimadzu Corporation) means a particle size of 99%.

In the method for producing SiOC ceramics according to the present invention, the above-mentioned polymerized product or pre-pulverized polymerized product is subjected to primary firing at a temperature exceeding 200 ° C. and 800 ° C. or less, and pulverized and classified to produce a primary fired powder. .
The heating temperature at the time of the primary firing treatment is more than 200 ° C and 800 ° C or less, more preferably 250 ° C to 750 ° C, and further preferably 400 ° C to 700 ° C. Moreover, 0.1-100 hours are preferable, the heating time at the time of a primary baking process has more preferable 0.3-75 hours, and 0.5-50 hours are further more preferable.

The heating atmosphere during the primary firing treatment is preferably an inert atmosphere or a vacuum atmosphere, and examples of the inert atmosphere include a rare gas atmosphere such as a nitrogen atmosphere or an argon atmosphere.
The primary firing treatment can be performed by heat treatment using a known firing furnace such as a tunnel furnace, an electric (electric heater) furnace, an induction heating furnace, an electromagnetic heating furnace, an electric furnace / electromagnetic hybrid furnace, or the like.

  In the method for producing SiOC ceramics of the present invention, by performing the primary firing treatment, a primary firing treatment product having an appropriate hardness can be obtained, and the yield of the pulverized product obtained after the primary firing can be improved.

  In the method for producing SiOC ceramics of the present invention, the primary fired product obtained by the primary firing process is pulverized and classified to produce a primary fired powder.

The pulverization is preferably performed using a pulverizer selected from known mechanical pulverizers such as a hammer mill, a pin mill, a jet mill, a bevel impactor, a turbo mill, a knife hammer mill, a rotary cutter mill, and a roll crusher.
The pulverization may be performed by combining a plurality of pulverizers.
What is necessary is just to adjust suitably the grinding | pulverization conditions of a grinding | pulverization apparatus so that the powder which has a desired characteristic etc. may be obtained.

  Classification is performed after the pulverization, and examples of the apparatus used for the classification include a rotor classifier, a vibration sieve, and an airflow classifier.

  In the method for producing SiOC ceramics according to the present invention, the primary fired powder obtained by pulverizing and classifying the primary fired material is preferably one having a maximum particle size of 100 μm or less, preferably 75 μm or less. More preferably, it is more preferably 50 μm or less.

In the method for producing a SiOC ceramic of the present invention, the primary fired product is pulverized and classified to obtain a 50% cumulative particle size in the tap density, BET specific surface area and volume-based cumulative particle size distribution of the resulting SiOC ceramic. You can easily adjust the particle diameter D ₅₀ and the like.
When an attempt is made to pulverize after secondary firing, generally the hardness of the secondary baked product is increased, making adjustment by the pulverization treatment difficult.

  In the present application documents, the maximum particle size of the primary fired powder is 99% of the cumulative particle size in the volume-based cumulative particle size distribution measured by a laser diffraction particle size distribution analyzer according to JIS Z8825-1: 2001. Specifically, for measurement, a sample obtained by adding 2 drops of ultra-small spatula and 2 drops of nonionic surfactant (Triton-X) to 50 ml of water and ultrasonically dispersing for 3 minutes A sample is assumed to mean a particle size of 99% in terms of an accumulated particle size in a volume-based accumulated particle size distribution measured using a laser diffraction particle size distribution measuring apparatus (SALD2000 manufactured by Shimadzu Corporation).

In the method for producing SiOC ceramics of the present invention, the primary fired powder is secondarily fired under a temperature condition of more than 800 ° C. and 1200 ° C. or less.
In the method for producing SiOC ceramics according to the present invention, the secondary firing is performed at a heating temperature of over 800 ° C. at 1200 ° C. or less, preferably at 850 to 1150 ° C., more preferably at 850 to 1100 ° C.
Moreover, 0.1-100 hours are preferable, the heating time at the time of a secondary baking process has more preferable 0.3-75 hours, and 0.5-50 hours are further more preferable.

The heating atmosphere during the secondary firing is preferably an inert atmosphere or a vacuum atmosphere, and examples of the inert atmosphere include a rare gas atmosphere such as a nitrogen atmosphere or an argon atmosphere.
Note that the gas forming the inert atmosphere may include a reducing gas such as hydrogen gas.

  The secondary firing treatment can be performed by heat treatment using a known firing furnace such as a tunnel furnace, an electric (electric heater) furnace, an induction heating furnace, an electromagnetic heating furnace, an electric furnace / an electromagnetic hybrid furnace, or the like.

  In the method for producing a SiOC ceramic of the present invention, when the obtained SiOC ceramic is used as a negative electrode active material for a non-aqueous electrolyte secondary battery by performing the secondary firing treatment, excellent initial efficiency and discharge capacity are obtained. It can be demonstrated.

The details of the SiOC ceramics obtained by the production method of the present invention are as described in the description of the SiOC ceramics of the present invention.
In the production method of the present invention, the carbon-containing compound and the silicon-containing organic compound are mixed and polymerized in a specific order, and then subjected to a firing treatment. SiOC ceramics can be formed while improving, and as a result, the obtained SiOC ceramics have excellent discharge capacity and cycle characteristics (cycle retention rate) when used as a negative electrode active material for non-aqueous electrolyte secondary batteries. It can be demonstrated.

  According to the present invention, when used as a negative electrode active material for a non-aqueous electrolyte secondary battery, SiOC ceramics exhibiting excellent discharge capacity and cycle characteristics (cycle retention rate) are easily and inexpensively industrially mass-produced. Can be provided.

A composite material can be appropriately formed from the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention.
As the composite material, the tap density at the time of tapping 1000 times, the BET specific surface area, and the particle size D ₅₀ of 50% in the integrated particle size distribution in the volume-based integrated particle size distribution are the above-described SiOC ceramics of the present invention. It is preferable that they are the same.

  Examples of the composite material include a composite material containing the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention and a conductive carbon material.

Examples of the conductive carbon material include conductive carbon materials such as acetylene black, ketjen black, furnace black, thermal black, and the like, carbon nanotubes, carbon fibers, graphene, expanded graphite, artificial graphite, natural graphite, and hard carbon. One or more types selected from can be mentioned.
The form of the conductive carbon material is not particularly limited, but is preferably a powder or a fibrous material, and is preferably capable of being uniformly dispersed in the SiOC ceramic.

When the composite material contains the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention and the conductive carbon material, the content of the conductive carbon material is 1% by mass to 30% by mass. %, Preferably 2% to 25% by weight, more preferably 3% to 20% by weight.
When the content is less than 1% by mass, it is difficult to exert an effect of lowering the electrical resistance value due to the conductive carbon material, and when it exceeds 30% by mass, it is used as a negative electrode active material for a non-aqueous electrolyte secondary battery. When the battery capacity is low.

  The composite material containing the SiOC ceramics and the conductive carbon material of the present invention can easily reduce the electric resistance by containing the conductive carbon material.

  As a method for producing the composite material containing the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention and a conductive carbon material, for example, in the above-described method for producing the SiOC ceramic of the present invention, ( 1) When preparing a dispersion by dispersing a carbon-containing compound in a solvent, a desired amount of conductive carbon material is mixed, or (2) a silicon-containing organic compound is mixed in a dispersion in which a carbon-containing compound is dispersed in a solvent. When preparing a mixed solution, a desired amount is mixed, or (3) a conductive carbon material is mixed with a desired amount of a conductive carbon material in a mixed solution containing a carbon-containing compound and a silicon-containing organic compound. Except for mixing, it can be prepared by the same method as the above-described method for producing the SiOC ceramic of the present invention.

  As the SiOC ceramic composite material having the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention, silicon oxycarbide ceramic is applied to the surface of the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention. Examples thereof include a silicon oxycarbide ceramic composite material provided with a carbon coating.

The thickness of the carbon coating containing the silicon oxycarbide ceramic is preferably 0.01 to 10 μm, more preferably 0.02 to 7 μm, and still more preferably 0.05 to 5 μm.
When the thickness exceeds 10 μm, the pores on the surface of the SiOC ceramic to be coated are reduced or the penetration of the electrolytic solution into the pores is easily inhibited, and the thickness is less than 0.01 μm. In some cases, it becomes difficult to achieve a desired effect.

  When the SiOC ceramic composite material of the present invention further has a carbon coating containing silicon oxycarbide ceramics on the surface, the contact electrical resistance between particles made of SiOC ceramics can be easily reduced. In addition, when used as a negative electrode active material for a non-aqueous electrolyte secondary battery, it is possible to suppress the decomposition of the electrolytic solution and to reduce the loss of internal resistance, thereby improving the cycle retention rate. The input / output characteristics can be improved.

  In addition, in this application document, the thickness of the carbon film containing SiOC means an arithmetic average value when 50 points are measured by EDX mapping of a field emission scanning electron microscope (FE-SEM). For this, an electrolytic radiation scanning electron microscope (FE-SEM (JSM-6340F) manufactured by JEOL) was used, and a cross section obtained by cutting the measurement sample by ion milling (manufactured by Gatan, model-691) was observed by EDX mapping. And the carbon film containing SiOC is specified, and the arithmetic mean value when the film thickness of 50 points | pieces is measured is meant.

Further, in the present application documents, the carbon coating containing silicon oxycarbide ceramics means a material having a higher carbon atom content than silicon oxycarbide ceramics constituting the SiOC ceramics to be coated. The ratio is preferably 25 to 100%, more preferably 27 to 100%, and still more preferably 30 to 100%.
The carbon film containing silicon oxycarbide ceramics preferably has an Si atom atomic ratio of 10 to 50%, more preferably 12 to 45%, and even more preferably 15 to 40%. When the atomic ratio of the Si atoms is less than 0.1%, when the SiOC ceramic composite material of the present invention is used as a negative electrode active material of a non-aqueous electrolyte secondary battery, the discharge capacity tends to decrease, and the Si If the atomic ratio of the atoms exceeds 50%, the cycle characteristics (cycle maintenance ratio) tend to be lowered when the SiOC ceramic composite material of the present invention is used as the negative electrode active material of the nonaqueous electrolyte secondary battery.
The carbon coating containing silicon oxycarbide ceramics preferably has an O atom ratio of 10 to 50%, more preferably 12 to 45%, and even more preferably 15 to 40%.

  In the present application documents, the atomic ratio of Si atom, O atom, and carbon atom means a value specified by the method described in Solid state ionics, 225 (2012) p.522-526, specifically, This means a value calculated by identifying the carbon atom and oxygen atom amounts with the carbon analyzer (LECO, C-200) and N / O analyzer (LECO, TC-436) and setting the remaining amount as Si atoms. .

  As a method for producing a SiOC ceramic composite material having a carbon coating containing the silicon oxycarbide ceramic on the surface, a carbon precursor and a silicon-containing organic material are formed on the surface of the SiOC ceramic of the present invention produced by the method described above. A method in which a silicon oxycarbide ceramic precursor, which is a mixture with a compound, is coated, polymerized, and then crushed (disintegrated) (hereinafter referred to as a composite material production method (I)), a carbon precursor or a carbon precursor A method of polymerizing a silicon oxycarbide ceramic precursor, which is a mixture of an organic compound and a silicon-containing organic compound, followed by mixing with the SiOC ceramic of the present invention produced by the method described above, and then crushing (breaking) (Referred to as the production method (II) of the material).

Examples of the carbon precursor include petroleum-based, coal-based or synthetic pitches and tars such as coal tar, coal tar pitch, petroleum pitch, fluid cracking bottom oil (FCC-DO), and ethylene bottom oil (EHC). One or more selected from the group consisting of: acrylic resins such as phenol resins, furan resins, polyacrylonitrile, poly (α-halogenated acrylonitrile); thermoplastic resins such as polyamideimide resins, polyamide resins, and polyimide resins; One or more types selected from thermosetting resins and sugars can be used.
As the carbon precursor, pitch or phenol resin can be suitably used in terms of cost or battery characteristics.

Moreover, as a silicon containing organic compound, the thing similar to the silicon containing organic compound used with the manufacturing method of the SiOC ceramics of this invention mentioned above can be mentioned.
The silicon oxycarbide ceramic precursor can be prepared by mixing the carbon precursor and the silicon-containing organic compound in a desired ratio.

  You may handle the said silicon oxycarbide ceramic precursor in the state melt | dissolved in the solvent suitably.

  The solvent is not particularly limited as long as it can dissolve the carbon precursor or silicon oxycarbide ceramic precursor. For example, methanol, ethanol, propanol, butanol, acetone, methyl ketone, tetrahydrofuran, dimethylformamide, dimethylacetamide And at least one selected from polar solvents such as dimethyl sulfoxide and acetonitrile, ethylene glycol, anthracene oil, creosote oil and FCC decant oil (FCCDO).

The amount of the solvent used is preferably 10 to 1000 parts by mass and more preferably 100 to 500 parts by mass with respect to 100 parts by mass of the carbon precursor.
When the amount of the solvent used is less than 10 parts by mass with respect to 100 parts by mass of the carbon precursor, it may be difficult to dissolve the carbon precursor and it may be difficult to uniformly polymerize the carbon precursor. On the other hand, when the amount exceeds 1000 parts by mass, the excess solvent tends to increase and the cost increases.
By using the solvent, it becomes easy to uniformly coat the silicon oxycarbide ceramic precursor on the SiOC ceramic of the present invention.

The silicon oxycarbide ceramic precursor preferably contains a polymerization catalyst.
Examples of the polymerization catalyst include an acid catalyst and a base catalyst.
Examples of the base catalyst include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, organic amines such as ammonia, monomethylamine and dimethylamine, and quaternary compounds such as tetramethylammonium hydroxide. One or more selected from ammonium salts can be mentioned.
Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, phosphoric acid, and boric acid, organic sulfonic acids such as p-toluenesulfonic acid, and organic acids such as formic acid, acetic acid, propionic acid, and benzoic acid. One or more kinds selected from organic dicarboxylic acids such as monocarboxylic acids, oxalic acid, malonic acid, succinic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid can be mentioned.
In view of operability and industrial stability, it is desirable to carry out the reaction under acidic conditions using an acid catalyst. Among them, the acid catalyst is a kind selected from p-toluenesulfonic acid, malonic acid and fumaric acid. It is preferable to use the above.

  When the surface of the SiOC ceramic of the present invention is coated with a silicon oxycarbide ceramic precursor, which is a mixture of a carbon precursor and a silicon-containing organic compound, and polymerized by the above-described composite material production method (I), Examples of the method for coating the surface of the SiOC ceramic with the carbon precursor or silicon oxycarbide ceramic precursor include a method of mixing the SiOC ceramic of the present invention with the carbon precursor or silicon oxycarbide ceramic precursor. Examples of the method of coating the carbon precursor or silicon oxycarbide ceramic precursor and performing the polymerization treatment include a method of performing the mixing treatment under heating conditions.

  The mixing treatment is preferably performed by a known mixer capable of heat treatment, and examples of such a mixer include a mixer that has a stirring shaft inside and is equipped with a stirring blade attached to the stirring shaft. Specific examples include Henschel mixer (manufactured by Nippon Coke Kogyo Co., Ltd.), high speed mixer (manufactured by Fukae Powtech Co., Ltd.), Redige mixer (manufactured by Matsubo Co., Ltd.), kneader, universal mixer be able to.

  The mixing treatment is preferably performed so that the shear rate is 0.1 to 20000 (1 / second), more preferably 0.5 to 17500 (1 / second). It is more preferable to carry out so that it may become 15000 (1 / second).

When the polymerization treatment is performed by performing the above mixing treatment under heating conditions, the treatment temperature is preferably a temperature that is higher than the melting temperature of the carbon precursor and lower than the carbonization temperature, specifically, 0 to 200 ° C. Preferably, 20-200 degreeC is more preferable.
The polymerization time is preferably 0.01 to 240 hours, more preferably 0.05 to 220 hours, and further preferably 0.1 to 200 hours.

The mixing treatment or the polymerization treatment is preferably performed in an inert atmosphere, and examples of the inert atmosphere include a rare gas atmosphere such as a nitrogen atmosphere and an argon atmosphere.
The mixing treatment or the polymerization treatment is more preferably performed in a non-water atmosphere, and examples of the non-water atmosphere include a rare gas atmosphere such as a dehydrated nitrogen atmosphere and an argon atmosphere. When water is present during the mixing or polymerization treatment, silicification of the silicon-containing organic compound is likely to proceed. Therefore, when the obtained SiOC ceramic composite material is used as a negative electrode active material for a non-aqueous electrolyte secondary battery, the battery The capacity tends to decrease and the battery characteristics tend to decrease.

  By the above mixing treatment, the silicon oxycarbide ceramic precursor adheres to the surface of the SiOC ceramic of the present invention to form a film, and the above mixing treatment is performed under temperature conditions at which the silicon oxycarbide ceramic precursor starts a polymerization reaction. Thereby, the carbon film containing silicon oxycarbide ceramics can be formed on the surface of the SiOC ceramic of the present invention.

  When the silicon oxycarbide ceramic precursor, which is a mixture of the carbon precursor and the silicon-containing organic compound, is polymerized and then mixed with the SiOC ceramic of the present invention by the above-described composite material production method (II), The details of the treatment temperature, treatment time, and treatment atmosphere are the same as in the above-described method (I) for producing a composite material, and a mixing apparatus used when the obtained polymerized product is mixed with the SiOC ceramic of the present invention. The details of the shear rate and the processing atmosphere are also the same as in the case of the above-described composite material production method (I).

After the surface of the SiOC ceramic of the present invention is coated with a silicon oxycarbide ceramic precursor, which is a mixture of a carbon precursor and a silicon-containing organic compound, and polymerized by the production method (I) of the composite material, A silicon oxycarbide ceramic precursor, which is a mixture of a carbon precursor and a silicon-containing organic compound, is polymerized by the material production method (II), mixed with the SiOC ceramic of the present invention, and then in a vacuum or under an inert atmosphere. It is preferable to remove the solvent and the like by heating with.
30-200 degreeC is preferable, the heating temperature which removes a solvent etc. has more preferable 50-200 degreeC, and 70-200 degreeC is further more preferable. When the heating temperature is less than 30 ° C., it takes a long time to remove the solvent and the like.
The carbon film containing silicon oxycarbide ceramics can also be cured by the heat treatment.

The reaction product obtained by the heat treatment is preferably further baked in an inert atmosphere such as a rare gas atmosphere such as a nitrogen atmosphere or an argon atmosphere or in a vacuum.
800-1200 degreeC is preferable, the temperature at the time of the said baking processing has more preferable 900-1150 degreeC, and 1000-1100 degreeC is further more preferable.
Moreover, 0.1-100 hours are preferable, as for baking processing time, 0.3-75 hours are more preferable, and 0.5-50 hours are further more preferable.

In the production method (I) of the composite material amount or the production method (II) of the composite material, the obtained fired product is pulverized (pulverized) to a maximum particle size of 100 μm or less after the polymerization treatment, preferably after the firing treatment. It is preferable to process, it is more preferable to grind | pulverize (disintegrate) to 75 micrometers or less, and it is further more preferable to grind | pulverize (disintegrate) to 50 micrometers or less.
The pulverization is preferably performed using a pulverizer selected from known mechanical pulverizers such as a hammer mill, a pin mill, a jet mill, a bevel impactor, a turbo mill, a knife hammer mill, a rotary cutter mill, and a roll crusher.
The pulverization may be performed by combining a plurality of pulverizers.
What is necessary is just to adjust suitably the grinding | pulverization conditions of a grinding | pulverization apparatus so that the powder which has a desired characteristic etc. may be obtained.

  Classification may be performed as necessary after the pulverization, and examples of the apparatus used for the classification include a rotor classifier, a vibration sieve, and an airflow classifier.

The classification treatment after the grinding process or grinding, the tap density of SiOC ceramics constituting the obtained SiOC ceramic composite material, a reduction of 50% of the particle diameter D ₅₀ in cumulative particle size of the BET specific surface area and volume-based cumulative particle size distribution suppressed It becomes easy to do.

In the present application documents, the maximum particle size of the pulverized product is 99% in terms of the cumulative particle size in the volume-based cumulative particle size distribution measured by a laser diffraction particle size distribution analyzer according to JIS Z8825-1: 2001. Specifically, for measurement, a sample obtained by adding 2 drops of ultra-small spatula and 2 drops of nonionic surfactant (Triton-X) to 50 ml of water and ultrasonically dispersing for 3 minutes A sample is assumed to mean a particle size of 99% in terms of an accumulated particle size in a volume-based accumulated particle size distribution measured using a laser diffraction particle size distribution measuring apparatus (SALD2000 manufactured by Shimadzu Corporation).

In this way, a silicon oxycarbide ceramic composite material having a carbon film containing silicon oxycarbide ceramics on the surface can be produced.
The obtained silicon oxycarbide ceramic composite material can easily be used as a negative electrode active material for a nonaqueous electrolyte secondary battery by easily reducing the contact electrical resistance between particles made of SiOC ceramics.

Next, the nonaqueous electrolyte secondary battery of the present invention will be described.
The nonaqueous electrolyte secondary battery of the present invention includes the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention as a negative electrode active material.
The nonaqueous electrolyte secondary battery of the present invention may contain the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention as it is, or the SiOC ceramic of the present invention or of the present invention. It may include those obtained by processing SiOC ceramics obtained by the manufacturing method into the form of the SiOC composite material of the present invention.
Examples of the nonaqueous electrolyte secondary battery of the present invention include a nonaqueous electrolyte lithium battery.

  In the non-aqueous electrolyte secondary battery of the present invention, the negative electrode is formed, for example, on a negative electrode current collector by forming a film containing the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention and a binder. Can be mentioned.

  Although it does not restrict | limit especially as said binder, Specifically, 1 or more types chosen from resin, such as fluorine resin (polyvinylidene fluoride, polytetrafluoroethylene, etc.), a styrene-butadiene resin, a polyimide resin, can be mentioned. .

  In the nonaqueous electrolyte secondary battery of the present invention, the negative electrode is formed by forming a film containing the binder on the negative electrode current collector, the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention, and the binder. In this case, the amount of the binder is not particularly limited, but is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention, and 3 to 25 It is more preferable that it is a mass part, and it is still more preferable that it is 5-20 mass parts.

  When the amount of the binder is outside the above range, the adhesion strength on the surface of the negative electrode current collector tends to be insufficient, or an insulating layer that causes an increase in electrode internal resistance may be formed.

The film containing the SiOC ceramic and the binder formed on the negative electrode current collector may contain any additive.
As said additive, negative electrode active materials, such as a conductive support agent and graphite, can be mentioned, for example.
As said conductive support agent, 1 or more types chosen from carbon black (Ketjen black, acetylene black, etc.), carbon fiber, a carbon nanotube, etc. can be mentioned.
Although the usage-amount of a conductive support agent is not restrict | limited in particular, it is preferable that it is 5-30 mass parts with respect to 100 mass parts of SiOC ceramics, and it is more preferable that it is 5-20 mass parts.
When the film containing the SiOC ceramics and the binder formed on the negative electrode current collector contains a conductive auxiliary agent, it is possible to exhibit excellent conductivity and suppress a decrease in charge / discharge capacity of the electrode.

  The film thickness of the film containing the SiOC ceramic and the binder formed on the negative electrode current collector is, for example, preferably 10 to 300 μm, and more preferably 20 to 200 μm.

  In addition, in this application document, the film thickness of the film containing the SiOC ceramics and the binder means an arithmetic average value when 50 points are measured with a field emission scanning electron microscope (FE-SEM). For this, an electrolytic emission scanning electron microscope (FE-SEM (JSM-6340F) manufactured by JEOL) was used, and a cross section of the measurement sample cut by ion milling (manufactured by Gatan, model-691) was observed. It means an arithmetic average value when a film containing SiOC ceramics and a binder is specified and the film thickness at 50 points is measured.

  The negative electrode current collector is not particularly limited, and specific examples include a plate, a mesh, a foil, and the like made of copper, nickel, or an alloy thereof.

  In the nonaqueous electrolyte secondary battery of the present invention, the negative electrode is formed by mixing, for example, the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention, a binder and a solvent, The obtained paste-like material can be produced by a method of pressure bonding on a current collector or coating on a current collector and then drying to form an electrode.

Specific examples of the binder include those described above. Moreover, the usage-amount of a binder is also the same as the mixing | blending ratio of the binder mentioned above.
When the amount of the binder is outside the above range, the adhesion strength on the surface of the negative electrode current collector tends to be insufficient, and an insulating layer that causes an increase in electrode internal resistance may be formed.

As the solvent for forming the paste-like material, a solvent that can dissolve or disperse the binder is usually used, and specific examples thereof include organic solvents such as N-methylpyrrolidone and N, N-dimethylformamide. it can.
The amount of the solvent used is not particularly limited as long as a paste-like material can be formed. For example, the amount of the solvent is 0 with respect to 100 parts by mass of the total amount of the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention and the binder. It is preferably 0.01 to 500 parts by mass, more preferably 0.01 to 400 parts by mass, and still more preferably 0.01 to 300 parts by mass.

  Arbitrary additives may be blended with the paste-like material, and specific examples of additives and blending ratios of the additives are as described above.

  The method for preparing the paste-like product is not particularly limited. For example, a method of mixing the SiOC ceramic of the present invention or the SiOC ceramic obtained by the manufacturing method of the present invention with a mixed liquid (or dispersion) of a binder and a solvent. It can be illustrated.

The thickness of the paste applied to the negative electrode current collector is preferably 30 to 500 μm, and more preferably 50 to 300 μm.
After applying the paste, it is preferable to appropriately perform a drying process, and the drying means is not particularly limited, but a heating vacuum drying process is preferable.

An electrode compact can be produced by the above method.
When the SiOC ceramic of the present invention or the SiOC ceramic obtained by the production method of the present invention is in a fibrous form, it is arranged in a uniaxial direction with respect to the negative electrode current collector or processed into a shape of a structure such as a fabric. The electrode molded body may be produced by bundling or braiding with conductive fibers such as metal or conductive polymer.
In forming the electrode molded body, terminals may be combined as necessary.

A battery may be assembled using the electrode molded body obtained by the above-described method as it is as a negative electrode, but prior to this or after assembling the lithium metal as an active material supported on the electrode molded body, It is good also as an electrode.
By carrying lithium metal, the irreversible capacity during the initial charge can be greatly reduced.
Examples of the method for supporting lithium metal include a chemical method, a physical method, and an electrochemical method. For example, an electrode molded body is immersed in a lithium ion-containing electrolytic solution, and the lithium metal is used for the counter electrode. Examples thereof include a method of impregnation, a method of mixing metallic lithium powder during preparation of the negative electrode, and a method of electrically contacting metallic lithium with an electrode molded body.

  The nonaqueous electrolyte secondary battery of the present invention has a battery component such as a positive electrode capable of occluding and releasing lithium, an electrolytic solution, a separator, a current collector, a gasket, a sealing plate, and a case together with the negative electrode. These battery components can be assembled and manufactured by conventional methods.

  In the nonaqueous electrolyte secondary battery of the present invention, the positive electrode is not particularly limited, and examples thereof include a positive electrode current collector, a positive electrode active material, a conductive material, and the like.

Examples of the positive electrode current collector include aluminum.
The positive electrode active material is not particularly limited as long as it can occlude / desorb an electrolytic solution such as lithium ion, and examples thereof include TiS ₂ , MoS ₃ , NbSe ₃ , FeS, VS ₂ , and VSe ₂ . Metal chalcogenide having a layered structure, CoO ₂ , Cr ₃ O ₅ , TiO ₂ , CuO, V ₃ O ₆ , Mo ₃ O, V ₂ O ₅ (· P ₂ O ₅ ), Mn ₂ O (· Li ₂ O ), LiCoO ₂ , LiNiO ₂ , LiMn ₂ O _{4 and} other metal oxides, iron phosphate-based materials, and the like.
Examples of the positive active _material, LiCoO _2, LiNiO 2, one or more selected from lithium composite oxide such as LiMn ₂ O ₄ are preferred.
Examples of the conductive material used for the positive electrode active material include one or more selected from graphite, carbon nanotubes, carbon nanofibers, carbon black, and the like.

In the non-aqueous electrolyte secondary battery of the present invention, the electrolytic solution is not particularly limited, and examples thereof include a solution in which an electrolyte is dissolved in an organic solvent.
As the electrolyte, for _{example, LiPF 6, LiClO 4, LiBF} 4, LiClF 4, LiAsF 6, LiSbF 6, LiAlO 4, LiAlCl 4, LiCl, can be exemplified one or more selected from lithium salts such as LiI.
Examples of the organic solvent include carbonates (propylene carbonate, ethylene carbonate, diethyl carbonate, etc.), lactones (γ-butyrolactone, etc.), chain ethers (1,2-dimethoxyethane, dimethyl ether, diethyl ether, etc.). ), Cyclic ethers (tetrahydrofuran, 2-methyltetrahydrofuran, dioxolane, 4-methyldioxolane, etc.), sulfolanes (sulfolane, etc.), sulfoxides (dimethylsulfoxide, etc.), nitriles (acetonitrile, propionitrile, benzonitrile, etc.) And one or more selected from aprotic solvents such as amides (N, N-dimethylformamide, N, N-dimethylacetamide, etc.), polyoxyalkylene glycols (diethylene glycol, etc.) Rukoto can.
For example, the electrolyte concentration is preferably one containing 0.3 to 5 mol of electrolyte, more preferably 0.5 to 3 mol, and more preferably 0.8 to 1.5 mol in 1 L of the electrolyte solution. Further preferred.

  In the nonaqueous electrolyte secondary battery of the present invention, the separator is not particularly limited, and for example, one or more selected from polyolefin-based porous films such as porous polypropylene nonwoven fabric and porous polyethylene nonwoven fabric Can be mentioned.

The non-aqueous electrolyte secondary battery of the present invention can take various forms such as a laminated form, a pack form, a button form, a gum form, an assembled battery form, and a square form.
Since the non-aqueous electrolyte secondary battery of the present invention contains the SiOC ceramics of the present invention, it is lightweight, has a high capacity, and has a high energy density. Therefore, the video camera, personal computer, word processor, radio cassette, mobile phone, etc. It can be suitably used as a power source or auxiliary power source for portable electronic devices, a driving power source for vehicles, and an auxiliary power source.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by the following examples.

Example 1
In a 4-neck flask under Ar flow, 18.6 g of novolak type phenolic resin (manufactured by Gunei Chemical Industry Co., Ltd., PSM4261) 60 ml of acetone (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 57 ° C.) 108.6 g of tetraethoxysilane (manufactured by Tama Chemical Co., Ltd., TEOS45) was added dropwise with stirring at about 130 rpm using a stirrer (BLW300 manufactured by HELDON), and the boiling point was 78 ° C. A mixture was obtained. Thereafter, 4.68 g of p-toluenesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd. (Wako) Co., Ltd.) was added as an acid catalyst to the obtained mixed solution to initiate polymerization. It heated to 78 degreeC with the temperature increase rate of 25 degreeC / hour, and hold | maintained for 20 hours after that, and refluxed. Next, after the obtained reaction liquid was sufficiently cooled, the solvent removal treatment was carried out by maintaining the temperature in a vacuum at 200 ° C. for 12 hours in an evaporator.

(Primary firing, grinding, classification, secondary firing)
The obtained polymer was subjected to primary firing by being held at 600 ° C. for 1 hour in an Ar atmosphere. After firing, it was pulverized with a cutter mill and classified with a 270 mesh sieve.
Then, secondary calcination was performed by holding the obtained pulverized and classified product in an Ar atmosphere at a temperature of 1000 ° C. for 3 hours to obtain a desired SiOC ceramic powder.

(Powder characteristics)
The obtained SiOC ceramic powder has a tap density of 1.13 g / cm ³ when tapped 1000 times, a BET specific surface area of 6 m ² / g, and a particle size D of 50% as an integrated particle size in a volume-based integrated particle size distribution. ₅₀ was 13 μm. The results are shown in Table 1.

<Preparation of lithium secondary battery for evaluation>
(A-1) Production of negative electrode To 10 g of the above-mentioned SiOC ceramics, 0.71 g of ketjen black, 5.88 g of polyimide as a binder, and 6 g of N-methyl-2-pyrrolidone as a solvent were added and stirred for 5 minutes in total. A negative electrode mixture paste was prepared.
The obtained negative electrode mixture paste was applied to a 18 μm thick copper foil (negative electrode current collector) with a doctor blade and heated to a temperature of 130 ° C. in a vacuum to completely evaporate the solvent. An electrode sheet was obtained in which a film containing SiOC ceramics having a thickness of about 50 μm and a binder was formed on the surface of the copper foil.
The obtained electrode sheet was rolled with a roller press and punched with a punch to produce a 2 cm ² negative electrode (working electrode).
(A-2) Production of positive electrode A positive electrode (counter electrode) was produced by indenting a lithium metal foil into a nickel mesh (current collector) having a thickness of 270 μm punched with a punch under an inert atmosphere. .

(B) Assembly of lithium secondary battery for evaluation As an electrolytic solution, a 1: 1 mixed solution of ethylene carbonate (EC) in which 1 mol / dm ³ of lithium salt LiPF ₆ was dissolved and diethyl carbonate (DEC) was used. In an inert atmosphere, as shown in FIG. 1, a positive electrode (counter electrode) 4, a separator 5, and a negative electrode (working electrode) 8 are embedded in the nickel mesh (current collector) 3 in the case 1. The button-type lithium secondary battery for evaluation having the form shown in FIG. 1 was prepared by assembling the spacers 7 in a stacked state and sealing them with a sealing lid (cap) 2 via a spring 6.

(1st discharge capacity)
In the obtained lithium secondary battery for evaluation, with respect to the initial battery measurement, constant current charging was performed at 0.405 mA and a final voltage of 5 mV, and then a constant potential was maintained until the lower limit current was 0.0405 mA. Next, constant current discharge was performed at 0.405 mA to a final voltage of 3 V, and the discharge capacity after the end of one cycle was defined as the rated capacity (reversible capacity (mAh / g)). The above measurement was performed with six batteries, and the arithmetic average value was defined as the 1st discharge capacity. The results are shown in Table 1.

(Initial efficiency)
The initial efficiency of the obtained evaluation lithium secondary battery was determined from the following equation using the first charge capacity and discharge capacity. The results are shown in Table 1.
Initial efficiency (%) = (first discharge capacity (mAh / g) / first charge capacity (mAh / g)) × 100

(Cycle characteristics (40 cycle maintenance rate))
The rated capacity calculated in the initial measurement of the evaluation lithium secondary battery was set to 1 C, and after constant current charging to a final voltage of 5 mV at 0.1 C, a constant potential was maintained until the lower limit current became 0.01 C. Next, a constant current discharge was performed at 0.1 C to a final voltage of 3 V, and the cycle characteristics were evaluated by calculating the maintenance rate 40 times according to the following formula.
40 times maintenance rate (%) = (40th discharge capacity (mAh / g) / 1st discharge capacity (mAh / g)) × 100
In this evaluation, two lithium secondary batteries for evaluation were produced, the maintenance rate was calculated 40 times by the method described above, and the arithmetic average value was obtained. The results are shown in Table 1.

(Comparative Example 1)
18.6 g of novolak-type phenolic resin (manufactured by Gunei Chemical Industry Co., Ltd., PSM4261) and 108.6 g of tetraethoxysilane (manufactured by Tama Chemical Industry Co., Ltd., TEOS45) are introduced into a four-necked flask under Ar circulation. Then, the mixture was heated to 100 ° C. at a temperature increase rate of 25 ° C./hour while stirring at 130 rpm using a stirrer (BLW300 manufactured by HELDON).
Next, 4.68 g of p-toluenesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as an acid catalyst is dissolved in 5 ml of acetone (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 57 ° C.). Then, the polymerization was started by dropping, and then the temperature was raised to 150 ° C. at a rate of 25 ° C./hour and held for 20 hours to perform reflux. Next, after the obtained reaction liquid was sufficiently cooled, the solvent removal treatment was carried out by maintaining it in a vacuum at a temperature of 200 ° C. for 12 hours.

(Primary firing, grinding, classification, secondary firing)
The obtained polymer was subjected to primary firing by being held at 600 ° C. for 1 hour in an Ar atmosphere. After firing, it was pulverized with a cutter mill and classified with a 270 mesh sieve.
Then, secondary calcination was performed by holding the obtained pulverized and classified product in an Ar atmosphere at a temperature of 1000 ° C. for 3 hours to obtain a desired SiOC ceramic powder.

(Powder characteristics)
The obtained SiOC ceramic powder has a tap density of 1.13 g / cm ³ when tapped 1000 times, a BET specific surface area of 5 m ² / g, and a particle size D of 50% in the integrated particle size distribution in the volume-based integrated particle size distribution. ₅₀ was 13 μm. The results are shown in Table 1.
Further, in the same manner as in Example 1, the 1st discharge capacity, the initial efficiency, and the 40-cycle cycle retention ratio were obtained. The results are shown in Table 1.

(Comparative Example 2)
In a 4-necked flask under Ar circulation, 108.6 g of tetraethoxysilane (manufactured by Tama Chemical Co., Ltd., TEOS45) was stirred at about 130 rpm using a stirrer (BLW300 manufactured by HELDON), and a novolak type A dispersion obtained by dissolving and dispersing 18.6 g of a phenol resin (manufactured by Gunei Chemical Industry Co., Ltd., PSM4261) in 60 ml of acetone (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 65 ° C.) was added dropwise.
4.68 g of p-toluenesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an acid catalyst to the obtained mixture having a boiling point of 78 ° C. to initiate polymerization. It heated to 78 degreeC with the temperature increase rate of 25 degreeC / hour, and hold | maintained for 20 hours after that, and refluxed. Next, after the obtained reaction liquid was sufficiently cooled, the solvent removal treatment was carried out by maintaining it in a vacuum at a temperature of 200 ° C. for 12 hours.

(Primary firing, grinding, classification, secondary firing)
The obtained polymer was subjected to primary firing by being held at 600 ° C. for 1 hour in an Ar atmosphere. After firing, it was pulverized with a cutter mill and classified with a 270 mesh sieve.
Then, secondary calcination was performed by holding the obtained pulverized and classified product in an Ar atmosphere at a temperature of 1000 ° C. for 3 hours to obtain a desired SiOC ceramic powder.

(Powder characteristics)
The obtained SiOC ceramic powder has a tap density of 1.15 g / cm ³ when tapped 1000 times, a BET specific surface area of 6 m ² / g, and a particle size of 50% in the cumulative particle size in the volume-based cumulative particle size distribution. D ₅₀ was 10 μm. The results are shown in Table 1.
Further, in the same manner as in Example 1, the 1st discharge capacity, the initial efficiency, and the 40-cycle cycle retention ratio were obtained. The results are shown in Table 1.

(Example 2)
Except that the temperature during primary firing was changed to 400 ° C., the same treatment as in Example 1 was carried out to obtain the desired SiOC ceramic powder.
The obtained SiOC ceramic powder has a tap density of 1.11 g / cm ³ when tapped 1000 times, a BET specific surface area of 5 m ² / g, and a particle size D of 50% as an integrated particle size in a volume-based integrated particle size distribution. ₅₀ was 12 μm. The results are shown in Table 1.
Further, in the same manner as in Example 1, the 1st discharge capacity, the initial efficiency, and the 40-cycle cycle retention ratio were obtained. The results are shown in Table 1.

(Example 3)
Except that the temperature at the time of primary firing was changed to 800 ° C., the same treatment as in Example 1 was carried out to obtain the desired SiOC ceramic powder.
The obtained SiOC ceramic powder has a tap density of 1.15 g / cm ³ when tapped 1000 times, a BET specific surface area of 6 m ² / g, and a particle size D of 50% in the cumulative particle size in the volume-based cumulative particle size distribution. ₅₀ was 13 μm. The results are shown in Table 1.
Further, in the same manner as in Example 1, the 1st discharge capacity, the initial efficiency, and the 40-cycle cycle retention ratio were obtained. The results are shown in Table 1.

(Comparative Example 3)
Except having changed the temperature at the time of primary baking to 1000 degreeC, it processed similarly to Example 1, and obtained the powdery object of the target SiOC ceramics.
The obtained SiOC ceramic powder has a tap density of 1.20 g / cm ³ when tapped 1000 times, a BET specific surface area of 6 m ² / g, and a particle size D of 50% in the cumulative particle size in the volume-based cumulative particle size distribution. ₅₀ was 18 μm. The results are shown in Table 1.
Further, in the same manner as in Example 1, the 1st discharge capacity, the initial efficiency, and the 40-cycle cycle retention ratio were obtained. The results are shown in Table 1.

Example 4
By processing in the same manner as in Example 1, a powdery material of SiOC ceramics was obtained.
Next, 9.3 g of novolak-type phenolic resin (manufactured by Gunei Chemical Industry Co., Ltd., PSM4261) is dissolved in 25 ml of acetone (manufactured by Wako Pure Chemical Industries, Ltd. (wako) Co., Ltd.) in a 4-neck flask under Ar flow. It was. While stirring at about 130 rpm using a stirrer (BLW300 manufactured by HELDON), 0.93 g of tetraethoxysilane (manufactured by Tama Chemical Co., Ltd., TEOS45) was added dropwise. Thereafter, polymerization was started by adding 0.38 g of p-toluenesulfonic acid (manufactured by Wako) as an acid catalyst, and the mixture was heated to 67 ° C., which is a temperature near the boiling point of the solution, at a rate of temperature increase of 25 ° C./hour. The polymerization was terminated by maintaining for 20 hours.
100 g of the porous SiOC ceramic powder is added to the resulting polymerization solution, and the powder and the polymerization solution are mixed with a rotation / revolution mixer (Aritori Nertaro ARE-310, manufactured by THINKY) at 2000 rpm for 5 minutes. did.
Next, a curing treatment was performed at a temperature of 200 ° C. for 5 hours, and a firing treatment was performed in an Ar atmosphere at a temperature of 1000 ° C. for 3 hours. The obtained fired product is pulverized with a cutter mill, and sieved with a 270 mesh sieve, so that a carbon coating containing silicon oxycarbide ceramics having a thickness of 0.2 μm on the surface of silicon oxycarbide ceramics. A powdery material of a SiOC ceramic composite material provided with

The obtained powder of the SiOC ceramic composite material had a tap density of 1.10 g / cm ³ , a BET specific surface area of 6 m ² / g, and an average particle diameter D ₅₀ of 16 μm. The results are shown in Table 1.
Further, using the obtained SiOC ceramic composite material, in the same manner as in Example 1, the 1st discharge capacity, the initial efficiency, and the 40-cycle cycle retention ratio were obtained. The results are shown in Table 1.

From Table 1, the lithium secondary battery for evaluation produced using the SiOC ceramics or SiOC ceramic composite material obtained in Examples 1 to 4 is excellent in 1st discharge capacity, initial efficiency, and the like. It can be seen that when used as a negative electrode active material for a non-aqueous electrolyte secondary battery, it has excellent discharge capacity and cycle characteristics (cycle retention rate).
In addition, it can be seen from Table 1 that the SiOC ceramic composite material obtained in Example 4 is more excellent in cycle characteristics than the SiOC ceramic obtained in Example 1.

  On the other hand, from Table 1, the lithium secondary battery for evaluation produced using the silicon oxycarbide ceramics obtained in Comparative Examples 1 to 3 has low 1st discharge capacity and low initial efficiency, and has practically sufficient performance. It turns out that it cannot be demonstrated.

  According to the present invention, when used as a negative electrode active material for a non-aqueous electrolyte secondary battery, silicon oxycarbide ceramics exhibiting excellent discharge capacity and cycle characteristics (cycle retention rate) can be provided, and Provided is a method capable of industrially mass-producing carbide ceramics easily and at low cost, and further provides a silicon oxycarbide ceramic composite material using the silicon oxycarbide ceramic and a non-aqueous solution using the silicon oxycarbide ceramic as a negative electrode active material. An electrolyte secondary battery can be provided.

1 Case 2 Sealing lid (cap)
3 Current collector 4 Positive electrode 5 Separator 6 Spring 7 Spacer 8 Negative electrode 9 Gasket

Claims (7)

Silicon oxycarbide ceramics,
A silicon-containing organic compound is mixed with a dispersion obtained by dispersing a carbon-containing compound in a solvent to prepare a mixed solution,
Next, when the boiling point of the liquid mixture is T _b (° C.), after performing the polymerization treatment at a temperature between T _b −10 (° C.) and T _b (° C.),
The obtained product is subjected to primary firing at a temperature exceeding 200 ° C. and not more than 800 ° C., and pulverized and classified to produce a primary fired powder,
Silicon oxycarbide ceramics obtained by subjecting the primary fired powder to secondary firing under a temperature condition exceeding 800 ° C. and 1200 ° C. or less. A method for producing silicon oxycarbide ceramics,
A silicon-containing organic compound is mixed with a dispersion obtained by dispersing a carbon-containing compound in a solvent to prepare a mixed solution,
Then the boiling point of the mixture is taken as T _b, after polymerization treatment at a temperature between T from T b _-10 ° C. _b,
The obtained product is subjected to primary firing at a temperature exceeding 200 ° C. and not more than 800 ° C., and pulverized and classified to produce a primary fired powder,
A method for producing silicon oxycarbide ceramics, characterized in that the primary firing powder is subjected to secondary firing under a temperature condition of more than 800 ° C and not more than 1200 ° C.   The method for producing silicon oxycarbide ceramics according to claim 2, wherein the carbon-containing compound is a phenol resin having two or more OH groups.   The method for producing silicon oxycarbide ceramics according to claim 2 or 3, wherein the solvent is an oxygen-containing organic compound.   The method for producing silicon oxycarbide ceramics according to any one of claims 2 to 4, wherein the silicon-containing organic compound is an alkoxysilane compound having two or more alkoxy groups.   A carbon film containing silicon oxycarbide ceramics is provided on the surface of the silicon oxycarbide ceramics according to claim 1 or the silicon oxycarbide ceramics obtained by the production method according to any one of claims 2 to 5. A silicon oxycarbide ceramic composite material characterized by that.   A non-aqueous electrolyte secondary battery comprising the silicon oxycarbide ceramic according to claim 1 or the silicon oxycarbide ceramic obtained by the manufacturing method according to any one of claims 2 to 5 as a negative electrode active material. .