TW202026235A - Carbonaceous material, negative electrode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, method for producing carbonaceous material, carbide and method for producing carbide - Google Patents

Abstract

The present invention pertains to a carbonaceous material in which the nitrogen atom content according to elemental analysis is 0.4 mass% or more to less than 1.0 mass%, and the value of the half-width of the peak in the vicinity of 1360 cm-1 of the Raman spectrum observed by Laser Raman spectroscopy is 180-220 cm-1.

Description

Carbonaceous material, negative electrode for non-aqueous electrolyte secondary battery, non-aqueous electrolyte secondary battery and carbonaceous material manufacturing method, and carbide and carbide manufacturing method

The present invention relates to a carbonaceous material suitable for a negative electrode active material of a non-aqueous electrolyte secondary battery, a negative electrode for a non-aqueous electrolyte secondary battery containing the carbonaceous material, a non-aqueous electrolyte secondary battery having the negative electrode, and the carbonaceous material The manufacturing method. The present invention also relates to a carbide and a manufacturing method of the carbide. The carbide can be preferably used to manufacture a carbonaceous material suitable for a negative electrode active material of a non-aqueous electrolyte secondary battery. The present invention is more related to a method for manufacturing a carbonaceous material suitable for a negative electrode material and a conductive material of a secondary battery represented by a lithium ion secondary battery.

Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries are widely used in small mobile devices such as mobile phones and notebook computers because of their high energy density and excellent output characteristics. In recent years, it has also developed in-vehicle applications for hybrid vehicles and electric vehicles. As a negative electrode material for lithium ion secondary batteries, non-graphitizable carbon that can be doped (charged) and dedoped (discharged) with lithium in an amount exceeding the theoretical capacity of graphite of 372mAh/g has been developed, and has been used until now (for example, patent documents 1 and 2, and Non-Patent Document 1).

The non-graphitizable carbon can be obtained, for example, by heat treatment using sugars or the like as a carbon source. However, when the non-graphitizable carbon is produced using these raw materials, foaming and expansion occur during heat treatment, resulting in poor productivity, and the specific surface area tends to increase due to the heat treatment step.

In addition, the non-graphitizable carbon can also be obtained by heat treatment using coconut shell as a carbon source. However, metals are contained in these raw materials as impurities. Therefore, when these raw materials are used to produce non-graphitizable carbon, in addition to a refining step, the specific surface area increases and carbon is caused by the refining step. The tendency of the structure to partially fail. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2017-107856 A [Patent Document 2] Japanese Patent Application Laid-Open No. 10-21919 [Non-Patent Literature]

[Non-Patent Document 1] Journal of The Electrochemical Society, 2016, Vol.163, No.7, A1295-A1299

[The problem to be solved by the invention]

In recent years, research has been conducted on the application of lithium ion secondary batteries to automotive applications, etc., and further increases in capacity of lithium ion secondary batteries have been required.

Therefore, the object of the present invention is to provide a carbonaceous material suitable for negative electrode active materials, which can form a non-aqueous electrolyte secondary battery with high charge and discharge capacity and charge and discharge efficiency (such as lithium ion secondary batteries, sodium ion secondary batteries) Batteries, lithium-sulfur batteries, lithium-air batteries); and a negative electrode containing the carbonaceous material, a non-aqueous electrolyte secondary battery having the negative electrode, and a method for manufacturing the carbonaceous material. Another object of the present invention is to provide a manufacturing method, which is to obtain secondary batteries with good discharge capacity (such as lithium ion secondary batteries, sodium ion secondary batteries, Negative electrode materials for batteries, lithium-sulfur batteries, and lithium-air batteries, and carbonaceous materials for conductive materials (carbonaceous materials for non-aqueous electrolyte secondary batteries, etc.). [Means to solve the problem]

The inventor of the present case, as a result of detailed research in order to solve the above problem, found that the nitrogen atom content obtained by elemental analysis is 0.4% by mass or more and less than 1.0% by mass, and the Raman spectrum observed by laser Raman spectroscopy the peak of 1360cm ^-1 and a half value width of the near value 180 ~ 220cm ^-1 carbonaceous material, further by the method for producing the carbonaceous material of the present invention described below, more specifically the non-aqueous electrolyte secondary battery negative electrode The manufacturing method of carbonaceous material can solve the above-mentioned problems and complete the present invention.

That is, the present invention includes the following preferable aspects. [1] A carbonaceous material in which the nitrogen atom content obtained by elemental analysis is above 0.4% by mass and less than 1.0% by mass, and is one of the peaks near 1360cm ^-1 of the Raman spectrum observed by laser Raman spectroscopy The half-value width is 180～220cm ^{- 1} . [2] The carbonaceous material as in [1], wherein the specific surface area obtained by the BET method is less than 100 m ² /g. [3] The carbonaceous material as in [1] or [2], wherein the true density obtained by the BuOH method is above 1.45. [4] The carbonaceous material according to any one of [1] to [3], wherein the content of silicon element is less than 200 ppm. [5] The carbonaceous material according to any one of [1] to [4], wherein the average particle size D ₅₀ is less than 30 μm. [6] The carbonaceous material according to any one of [1] to [5], wherein the carbon plane spacing d ₀₀₂ calculated using the Bragg formula derived from the wide-angle X-ray diffraction method is 3.75Å or more. [7] The carbonaceous material of any one of [1] to [6], which is derived from a substance having a carbohydrate skeleton. [8] The carbonaceous material of [7], wherein the substance with a carbohydrate skeleton is a polysaccharide with no melting point. [9] A negative electrode for a non-aqueous electrolyte secondary battery, comprising the carbonaceous material of any one of [1] to [8]. [10] A non-aqueous electrolyte secondary battery having the negative electrode for the non-aqueous electrolyte secondary battery of [9]. [11] A method for producing a carbonaceous material according to any one of [1] to [8], which includes at least the following steps: (1) Under the supply of oxygen-containing gas, the temperature is 215-240°C The temperature range is the step of heat-treating the raw material of the carbon precursor for 1-12 hours to obtain the carbon precursor; (2A) In an inert gas environment, heating the carbon precursor to a temperature higher than 100°C/hour The step of the first temperature in the range of 500-900°C; (2B) the step of heat-treating the carbon precursor at a temperature of 500-900°C under the supply of inert gas to obtain carbide; here, inactive The amount of gas supplied is 0.01～5.0L/(minute･m ² ) per unit surface area of the carbon precursor; (3A) In an inert gas environment, at a heating rate above 100℃/hour, The step of heating the carbide to a second temperature in the range of 1000 to 1400°C; and (3B) the step of heat-treating the carbide at a temperature of 1000 to 1400°C under the supply of inert gas to obtain a carbonaceous material ; Here, the supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of carbide. [12] A method for producing a carbonaceous material according to any one of [1] to [8], which includes at least the following steps: (4) Combining the raw material of the carbon precursor with 100 parts by mass relative to the raw material The step of mixing 1-20 parts by mass of at least one organic acid to obtain a mixture; (5A) In an inert gas environment, heating the mixture to a temperature of 500-900°C at a temperature rising rate of 100°C/hour or more Step at the first temperature within the range; (5B) Under the supply of inert gas, heat-treating the mixture at a temperature of 500 to 900°C to obtain carbide; here, the amount of inert gas supplied is Each unit surface area of the raw materials contained in the mixture is 0.01～5.0L/(minute･m ² ); (6A) In an inert gas environment, the carbide is heated to a temperature higher than 100°C/hour A step of a second temperature in the range of 1000 to 1400°C; and (6B) a step of heat-treating the carbide at a temperature of 1000 to 1400°C under the supply of inert gas to obtain a carbonaceous material; The amount of active gas supplied is 0.01 to 5.0L/(minute･m ² ) per unit surface area of the carbide. [13] A method for manufacturing a carbonaceous material as described in any one of [1] to [8], which includes at least the following steps: (12A) In an inert gas environment, at a temperature of 100°C/hour or more The step of heating the polysaccharide to the first temperature in the range of 500-900°C at the rate of temperature increase; (12B) Under the supply of inert gas, the polysaccharide is heat-treated at a temperature of 500-900°C to obtain carbonization Here, the supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of polysaccharide; (13A) In an inert gas environment, 100 The step of heating the carbide to a second temperature in the range of 1000 to 1600°C at a temperature increase rate of ℃/hour or more; and (13B) the carbide at a temperature of 1000 to 1600°C under the supply of inert gas The step of performing heat treatment to obtain a carbonaceous material; here, the supply amount of the inert gas is 0.01 to 5.0 L/(min･m ² ) per unit surface area of the carbide. [14] The manufacturing method of [13], wherein the polysaccharide is cellulose or an analog thereof. [15] The manufacturing method of [13], wherein the polysaccharide includes a cross-linked structure. [16] A carbide in which the nitrogen atom content obtained by elemental analysis is 0.20% by mass to 0.90% by mass, and the half value of the peak near 1360cm ^-1 of the Raman spectrum observed by laser Raman spectroscopy The value of the width is 250cm ^-1 to 300cm ^-1 or less. [17] A method for producing a carbide as described in [16], which comprises at least: (1) Under the supply of oxygen-containing gas, heat treatment of the raw material of the carbon precursor at a temperature range of 215 to 240°C 1 to 12 hours to obtain a carbon precursor; (2A) in an inert gas environment, heating the carbon precursor to the first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more And (2B) the step of heat-treating the carbon precursor at a temperature of 500 to 900°C under the supply of inert gas to obtain carbide; here, the supply of inert gas is based on the amount of carbon precursor 0.01～5.0L/(minute･m ² ) per unit surface area. [18] A method for producing a carbide according to [16], which comprises at least: (4) A raw material of a carbon precursor and 1-20 parts by mass of at least one organic acid relative to 100 parts by mass of the raw material The step of mixing to obtain the mixture; (5A) The step of heating the mixture to the first temperature in the range of 500-900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment; and (5B) The step of heat-treating the mixture at a temperature of 500 to 900°C under the supply of inert gas to obtain carbides; here, the supply of inert gas is based on each unit surface area of the raw materials contained in the mixture It is 0.01～5.0L/(minute･m ² ). [Effects of Invention]

According to the carbonaceous material of the present invention, a non-aqueous electrolyte secondary battery having high charge and discharge capacity and charge and discharge efficiency can be provided. Moreover, in a preferred aspect of the present invention, a carbonaceous material that can form a non-aqueous electrolyte secondary battery with low internal resistance can also be provided, and can further improve the output and output characteristics of the non-aqueous electrolyte secondary battery. Furthermore, according to the present invention, it is possible to provide a manufacturing method capable of obtaining a carbonaceous material with high charge and discharge capacity and charge and discharge efficiency at a good recovery rate through a small number of steps from raw materials. More specifically, it is not Manufacturing method of carbonaceous material for water electrolyte secondary battery. In addition, in a preferred aspect of the present invention, a carbonaceous material capable of forming a non-aqueous electrolyte secondary battery with high discharge capacity and low internal resistance can also be provided.

The embodiments of the present invention will be described in detail below. In addition, the scope of the present invention is not limited to the embodiments described here, and various changes can be added without departing from the gist of the present invention.

In the carbonaceous material of the present invention, the nitrogen atom content obtained by elemental analysis is 0.4% by mass or more and less than 1.0% by mass. If the content of nitrogen atoms in the carbonaceous material is less than 0.4% by mass, there will be fewer vacancies for lithium ion absorption and desorption during charge and discharge, and sufficient charge and discharge capacity cannot be obtained. From the viewpoint of easy improvement of the charge and discharge capacity, the nitrogen atom content in the carbonaceous material of the present invention is preferably 0.45% by mass or more, more preferably 0.5% by mass or more, and still more preferably 0.6% by mass or more. In addition, when the nitrogen atom content in the carbonaceous material is 1.0% by mass or more, the structure of the carbonaceous material becomes easily strained, and the layered structure cannot be maintained. As a result, there are fewer vacancies for the absorption and desorption of lithium ions, and sufficient charge and discharge capacity cannot be obtained. In addition, when the nitrogen atom content is 1.0% by mass or more, the nitrogen atoms that do not enter the carbon skeleton are expected to exist as surface functional groups of, for example, -NH ₂ groups. If the amount of such surface functional groups increases, irreversible side reactions that may occur during charge and discharge cannot be suppressed, resulting in a decrease in discharge capacity and a decrease in charge and discharge efficiency. From the standpoints of suppressing irreversible side reactions during charge and discharge, and easily improving discharge capacity and charge and discharge efficiency, the carbonaceous material of the present invention preferably has a nitrogen atom content of 0.95 mass% or less, more preferably less than 0.95 mass% , More preferably 0.90 mass% or less, particularly preferably 0.85 mass% or less. The details of the measurement of the nitrogen atom content are described later, and are measured by the elemental analysis method (inert gas dissolution method). The method for adjusting the content of nitrogen atoms in the carbonaceous material within the above range is not limited, but for example, the method for producing carbonaceous materials described later can be used, which includes the use of carbonaceous materials as raw materials in an inert gas environment. The step of heat treatment of carbide. In particular, if the amount of inert gas supplied is increased, the heating rate is reduced, and the heat treatment temperature is increased, the nitrogen atoms tend to be easily separated. Therefore, the amount of inert gas supplied, the heating rate, and the heat treatment temperature can be adjusted. Adjust the nitrogen atom content to the expected range.

In the carbonaceous material of the present invention, the half-value width of the peak near 1360 cm ^-1 of the Raman spectrum observed by laser Raman spectroscopy is 180 to 220 cm ^-1 . Here, the peak near 1360 cm ^{-1 is} generally referred to as the Raman peak in the D band, which is a peak caused by the disorder and defect of the graphite structure. A peak near 1360cm ^-1, usually tied 1345cm ^-1 ~ 1375cm ^-1, preferably in the range of observed based 1350cm ^-1 ~ 1370cm ^-1's. In addition, the half-value width in this specification refers to the half-value full width.

The value of the half-value width of the peak near 1360cm ^-1 is related to the amount of disorder and defects of the graphite structure contained in the carbonaceous material. The disorder of this structure may be caused by the introduction of nitrogen atoms into the carbon skeleton, for example. The peak half value width in the vicinity of 1360cm ^-1 if the value is less than 180cm ^-1, the graphite structure of the carbonaceous material comprises defect-scattered too, because the developed graphite structure results in a reduction of the fine pores between the crystals. As a result, there are fewer vacancies for occluding lithium ions, resulting in a decrease in charge and discharge capacity. From the viewpoint of increasing the charge and discharge capacity, the half-value width of the peak near 1360 cm ^-1 is preferably 185 cm ^{- 1} or more, more preferably 190 cm ^{- 1} or more. In addition, if the half-value width is greater than 220 cm ^-1 , the graphite structure contained in the carbonaceous material will be scattered and defects will increase, resulting in an increase in amorphous quality and a decrease in vacancies that can store lithium. As a result, the occlusion amount of lithium ions is reduced, and the charge and discharge capacity is reduced. From the viewpoint of improving the charge-discharge capacity is easy to view, the half-peak of 1360cm ^-1 value close to the value of the width is preferably 215cm ^-1 or less, more preferably 214cm ^-1 or less, and still more preferably 213CM ^-1 or less, still more Preferably it is 212cm ^-1 or less, still more preferably 211cm ^-1 or less, still more preferably 210cm ^-1 or less, still more preferably 208cm ^-1 or less, still more preferably 206cm ^-1 or less, still more preferably 204cm ^-1 Below, it is particularly preferably 202 cm ^-1 or less.

Raman spectroscopy is measured using a Raman spectrometer (for example, a Raman spectrometer "LabRAM ARAMIS (VIS)" manufactured by Horiba Manufacturing Co., Ltd.). Specifically, for example, the measurement target particles are set on the observation platform stage, the objective lens is adjusted to a magnification of 100 times, and the focus is adjusted. While irradiating the measurement tank with 532nm argon ion laser light, the exposure time is 1 second and the accumulation Measure 100 times and the measuring range is 50～2000cm ^-1 .

The method of adjusting the half-value width of the peak near 1360 cm ^-1 to the above range is not limited. For example, the method for producing carbonaceous materials described later can be used, which involves the use of raw materials for carbonaceous materials in an inert gas environment. The carbides are heat treated. In particular, if the amount of inert gas supplied is increased, the temperature rise rate is decreased, and the heat treatment temperature is increased, the nitrogen atoms, which are the main cause of the disorganization of the graphite structure contained in the carbonaceous material, and the defects, are easily detached. There is a tendency for the value of the half-value width of the peak near 1360 cm ^{-1 to} decrease. Therefore, the supply amount of inert gas, the heating rate and the heat treatment temperature can be adjusted, and the value of the half-value width can be adjusted to the expected range.

The half peak of 1360cm ^-1 in the vicinity of the nitrogen atom content in the resultant elemental analysis of more than 0.4 mass% and less than 1.0% by mass and the observed Raman laser Raman spectroscopy spectrum of broad value is 180 ~ 220cm The carbonaceous material of the present invention of ^-1 has fine pores capable of sufficiently occluding lithium ions, and therefore can obtain high charge and discharge capacity. Furthermore, in a preferred aspect of the present invention, the carbonaceous material of the present invention having the above-mentioned characteristics has fewer carbon edges and a wider carbon plane, so the transport efficiency of lithium ions is increased, and as a result, low resistance can be achieved.

Strength of the carbon material of the present invention, the Raman spectrum of the peak intensity 1360cm ^-1 nearby (I ₁₃₆₀₎ and the vicinity of 1580cm ^-1 peak intensity (I ₁₅₈₀₎ of the ratio (R value = I ₁₃₆₀ / I _1580), from From the viewpoint of ease of reducing the internal resistance of the non-aqueous electrolyte secondary battery, 1.10 to 1.28 is preferable. Here, the peak near 1360 cm ^{-1 is} the Raman peak generally called the D band as described above for the half-value width, and it is a peak caused by the disorder and defect of the graphite structure. The peak near 1580 cm ^-1 is generally referred to as the Raman peak in the G band, which is derived from the peak of the graphite structure. Here, near the peak of 1580cm ^-1 generally based on 1565cm ^-1 ~ 1615cm ^-1, preferably in the range of observed based 1560cm ^-1 ~ 1610cm ^-1's.

The R value of the peak intensity ratio is related to the crystallinity of the carbonaceous material. If the crystallinity of the carbonaceous material is too high, the carbon edge will be reduced due to the development of the graphite structure, which will result in fewer Li insertion vacancies. Therefore, problems such as lowering of characteristics at low temperatures and higher resistance occur. In addition, if the crystallinity of the carbonaceous material is too low, the amorphous quality will increase, the carbon edges will increase, and the carbon terminal reactive groups that react with lithium will increase. Therefore, the utilization efficiency of lithium ions decreases. From the above viewpoints, the R value is preferably 1.10 or more, more preferably 1.13 or more, still more preferably 1.15 or more, and particularly preferably 1.17 or more. Moreover, the R value is preferably 1.28 or less, more preferably 1.25 or less, still more preferably 1.22 or less, and particularly preferably 1.20 or less.

The specific surface area of the carbonaceous material of the present invention obtained by the nitrogen adsorption BET method is preferably 100 m ² /g or less, more preferably 80 m ² /g or less, more preferably 60 m ² /g or less, and still more preferably 40 m ² /g or less, still good was 30m ² / g or less, and then the best of 28m ² / g or less, and then the best of 27m ² / g or less, and then the best of 26m ² / g or less, and particularly preferably 25m ² / g or less. When the specific surface area is below the above upper limit, the moisture absorption of the carbonaceous material is likely to decrease, and the amount of moisture present in the carbonaceous material is likely to decrease. As a result, the hydrolysis of the electrolyte and the electrolysis of water due to moisture can be suppressed, and the generation of acids and gases accompanying these phenomena can be easily suppressed. In addition, when the specific surface area is below the above upper limit, it is easy to reduce the contact area between air and the carbonaceous material, and it is easy to suppress the oxidation of the carbonaceous material body. The lower limit of the specific surface area of the carbonaceous material obtained by the nitrogen adsorption BET method is not particularly limited. From the viewpoint of easily increasing the contact area with the electrolyte and lowering the resistance of the battery, it is preferably 3 m ² /g or more. More preferably, it is 5 m ² /g or more. In this specification, the specific surface area obtained by the BET method means the specific surface area defined by the nitrogen adsorption BET multipoint method. Specifically, the method described later can be used for measurement.

The method of adjusting the specific surface area obtained by the BET method within the above-mentioned range is not limited. For example, in the method for producing carbonaceous materials described later, if the temperature of the step of obtaining the carbon precursor and/or the step of obtaining carbide is lowered, Or if the heating time is shortened, the BET specific surface area of the finally obtained carbonaceous material tends to increase due to the suppression of structural shrinkage caused by heat. Therefore, in order to obtain a carbonaceous material having a BET specific surface area within a desired range, it is only necessary to adjust the sintering temperature and the sintering time.

The true density (ρ _Bt ) of the carbonaceous material of the present invention obtained by the BuOH method is preferably 1.45 g/cm ³ or more, more preferably 1.47 g/cm ³ or more, and still more preferably 1.48 g/cm ³ or more. If the true density obtained by the BuOH method is above the above lower limit, it is easy to increase the capacity per unit mass in the battery. The upper limit of the true density is not particularly limited, but from the viewpoint of easily increasing the structure capable of absorbing lithium ions, it is preferably 1.80 g/cm ³ or less, more preferably 1.70 g/cm ³ or less, and still more preferably 1.65 g/cm ³ or less. The measurement method of true density by the butanol method is as described in the examples in detail. It can be measured by the butanol method in accordance with the method established by JIS R 7212. The carbonaceous material having such a true density can be manufactured using, for example, the carbonaceous material manufacturing method described later.

The true density (ρ _He ) of the carbonaceous material of the present invention obtained by the helium method is preferably 2.00 g/cm ³ or more, more preferably 2.01 g/cm ³ or more, and still more preferably 2.02 g/cm ³ or more. If the true density obtained by the helium method is above the above lower limit, it is easy to increase the capacity per unit mass in the battery. The upper limit of the true density is not particularly limited, but from the viewpoint of easily increasing the structure capable of occluding lithium ions, it is preferably 2.25 g/cm ³ or less, more preferably 2.15 g/cm ³ or less, and still more preferably 2.10 g/cm ³ or less. The details of the method for measuring the true density obtained by the helium method are as described in the examples, which can be measured by the gas substitution method in accordance with the method established by JIS R 1620. The carbonaceous material having such a true density can be manufactured using, for example, the carbonaceous material manufacturing method described later.

In the carbonaceous material of the present invention, the content of silicon element is preferably 200 ppm or less, more preferably 150 ppm or less, and still more preferably 100 ppm or less. If the silicon element content is below the above upper limit, it is easy to suppress the precipitation of silicon atoms and crystal growth during charging and discharging, and it is easy to suppress problems such as battery short circuit caused by this. In addition, the structure of the carbonaceous material is not easily destroyed due to the change in the volume of silicon atoms, and it is easy to maintain the charge and discharge capacity of the battery. The less silicon content in the carbonaceous material is, the better, and the particularly preferred carbonaceous material does not substantially contain silicon atoms. Here, the term "substantially not contained" means that the detection limit of the element analysis method (inert gas melting-heat conduction method) described later is ^10-6 mass% or less. The details of the measurement of the silicon content are as described in the examples, and can be measured using a fluorescent X-ray analyzer (for example, "ZSX Primus-μ" manufactured by Rigaku Co., Ltd.).

The average particle size D _{50 of the} carbonaceous material of the present invention is preferably 30 μm or less, more preferably 25 μm or less, still more preferably 20 μm or less, still more preferably 18 μm or less, particularly preferably 16 μm or less, and most preferably 15 μm or less. When the average particle size is less than the above upper limit, in addition to the better coatability during electrode production, the free path of lithium ion diffusion in the carbonaceous material particles is reduced, so rapid charge and discharge are easily obtained. Furthermore, in lithium ion secondary batteries, in order to improve the output/output characteristics, it is important to increase the electrode area. Therefore, when preparing the electrode, the coating thickness of the active material on the current collector plate must be made thin. When the average particle diameter of the carbonaceous material used as the active material is below the above upper limit, it is easy to make the coating thickness thin when preparing the electrode. In addition, the average particle size D _{50 of the} carbonaceous material of the present invention is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, still more preferably 5 μm or more, still more preferably 6 μm or more, and still more preferably It is 7 μm or more, more preferably 8 μm or more, and particularly preferably 9 μm or more. When the average particle diameter D ₅₀ is above the above lower limit, the increase in specific surface area and the increase in reactivity with the electrolyte caused by the fine powder in the carbonaceous material are suppressed, and the increase in irreversible capacity is easily suppressed. In addition, when a carbonaceous material is used to manufacture the negative electrode, it is easy to ensure the voids formed between the carbonaceous materials, the movement of lithium ions in the electrolyte is not easily suppressed, and the resistance of the non-aqueous electrolyte secondary battery is easily reduced. The average particle size D _{50 is the} particle size at which the cumulative volume becomes 50%. For example, the particle size distribution can be measured by the laser scattering method using a particle size and particle size distribution measuring device (Microtrac. Bel Co., Ltd. "Microtrac MT3300EXII") Find.

In the carbonaceous material of the present invention, the carbon surface spacing d ₀₀₂ calculated by the Bragg formula derived from the wide-angle X-ray diffraction method is preferably 3.75Å or more, more preferably 3.80Å or more, and still more preferably 3.81Å Above, particularly preferably 3.82Å or more. The carbon plane spacing d _{002 is} , for example, about 3.35 to 3.40Å when the carbon planes are closest like graphite. If it exceeds 4.00Å, the carbon planes cannot interact with each other, and the layer structure cannot be maintained. In the carbonaceous material of the present invention, if the carbon plane spacing d ₀₀₂ is greater than the above lower limit, lithium ions are likely to move efficiently, and the resistance of the non-aqueous electrolyte secondary battery is likely to be lowered. The carbon plane spacing d _{002 is} preferably 4.00° or less, more preferably 3.97° or less, still more preferably 3.95° or less from the viewpoint of easy maintenance of the layer structure. The details of the measurement method of the carbon surface interval d _{002 are} as described in the examples, which are calculated from the peak position (diffraction angle 2θ) observed by the powder X-ray diffraction method by Bragg's formula.

In the carbonaceous material of the present invention, the circularity is preferably 9.70 or more, more preferably 9.75 or more, and still more preferably 9.80 or more. When the circularity is above the above lower limit, the structure is sufficiently fixed, and the melting of carbonaceous materials and the fusion of carbonaceous materials are suppressed. As a result, a structure that allows lithium ions to be absorbed and desorbed is easily formed, and the charge and discharge capacity is easily increased. . In addition, it is easy to increase the electrode density. The upper limit of the circularity is not particularly limited, but is preferably 9.95 or less, more preferably 9.90 or less, and still more preferably 9.85 or less. The details of the measurement of circularity are as described in the examples, and it is measured by the shape particle size distribution measurement method described later.

The method for producing the carbonaceous material of the present invention is not particularly limited as long as the carbonaceous material of the present invention having the above-mentioned characteristics can be obtained, and it can be produced using, for example, a carbonaceous material production method including at least the following steps.

The present invention also provides a negative electrode active material or conductive material suitable for non-aqueous electrolyte secondary batteries (such as lithium ion secondary batteries, sodium ion batteries, lithium sulfur batteries, lithium air batteries) with high charge and discharge capacity and charge and discharge efficiency. Material manufacturing method of carbonaceous material.

In one aspect of the present invention, the manufacturing method of the carbonaceous material of the present invention includes at least the following steps: (1) Under the supply of oxygen-containing gas, the raw material of the carbon precursor is processed at a temperature ranging from 215 to 240°C. Heat treatment for 1-12 hours to obtain a carbon precursor; (2A) In an inert gas environment, heat the carbon precursor to the first in the range of 500-900°C at a temperature rising rate of 100°C/hour or more Step of temperature; (2B) Step of heat-treating the carbon precursor at a temperature of 500 to 900°C under the supply of inert gas to obtain carbide; here, the supply of inert gas is based on the carbon precursor 0.01～5.0L/(minute･m ² ) per unit surface area of the material; (3A) In an inert gas environment, heating the carbide to 1000～1400℃ at a temperature rising rate of 100℃/hour or more And (3B) the step of heat-treating the carbide at a temperature of 1000 to 1400°C under the supply of inert gas to obtain a carbonaceous material; here, the supply of inert gas The amount is 0.01～5.0L/(min･m ² ) per unit surface area of carbide.

In another aspect of the present invention, the manufacturing method of the carbonaceous material of the present invention includes at least the following steps: (4) Combining the raw material of the carbon precursor with at least 1-20 parts by mass relative to 100 parts by mass of the raw material The step of mixing 1 kind of organic acid to obtain the mixture; (5A) The step of heating the mixture to the first temperature in the range of 500-900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment; (5B) The step of heat-treating the mixture at a temperature of 500 to 900°C under the supply of inert gas to obtain carbide; here, the supply amount of inert gas is based on each of the raw materials contained in the mixture The unit surface area is 0.01～5.0L/(minute･m ² ); (6A) In an inert gas environment, the carbide is heated to the first in the range of 1000～1400℃ at a heating rate of 100℃/hour or more 2 temperature step; and (6B) the step of heat-treating the carbide at a temperature of 1000 to 1400°C under the supply of inert gas to obtain a carbonaceous material; here, the supply amount of inert gas is The surface area of carbide is 0.01～5.0L/(min･m ² ) per unit surface area.

In yet another aspect of the present invention, the method for producing a carbonaceous material of the present invention includes at least the following steps: (7) In a temperature range of 150 to 300°C, the raw material of the carbon precursor is compared to the raw material 50 parts by mass of 80-500 parts by mass of at least one heat-resistant oil is mixed and the mixture is heat-treated for 0.5-12 hours to obtain a carbon precursor; (8A) In an inert gas environment, at 100°C/hour The step of heating the carbon precursor to the first temperature in the range of 500 to 900°C at the above heating rate; (8B) Under the supply of inert gas, heat treating the carbon precursor at a temperature of 500 to 900°C And the step of obtaining carbide; here, the supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of the carbon precursor; (9A) In an inert gas environment , The step of heating the carbide to a second temperature in the range of 1000 to 1400°C at a temperature increase rate of 100°C/hour or more; and (9B) under the supply of inert gas, at a temperature of 1000 to 1400°C The step of heat-treating the carbide to obtain a carbonaceous material; here, the supply amount of the inert gas is 0.01 to 5.0 L/(min･m ² ) per unit surface area of the carbide.

The raw material of the carbon precursor described in the above steps (1), (4), and (7) is not particularly limited as long as it is capable of forming the carbonaceous material of the present invention through steps such as subsequent heat treatment, and may be, for example, Carbohydrates and the like, but from the viewpoint of easily obtaining the carbonaceous material of the present invention having the above-mentioned characteristics, a substance having a carbohydrate skeleton is preferable. By using a substance having a sugar skeleton as a raw material, a carbonaceous material derived from a substance having a sugar skeleton can be obtained. Examples of substances (sugars) having a carbohydrate backbone include monosaccharides such as glucose, galactose, mannose, fructose, ribose, and glucosamine; sucrose, trehalose, maltose, cellobiose, maltitol, and lactose Disaccharides such as acid and lactosamine; polysaccharides such as starch, glycogen, agarose, pectin, cellulose, chitin, and chitosan. Among these sugars, starch is preferred because it is easily available in large amounts.

As cellulose, cellulose analogs can also be used. Examples of cellulose analogs include those substituted with functional groups for the hydroxyl groups of cellulose, for example, acetyl cellulose (substituting part or all of the hydroxyl groups with acetyl groups), chitin (with acetyl acetone) The amine group replaces the hydroxyl group at the second position), chitosan (the amine group replaces the hydroxyl group at the second position), etc. From the viewpoint that the carbonaceous material can be obtained more simply, or from the viewpoint of simplifying the steps by omitting the pulverization and classification steps, and improving the recovery rate, polysaccharides that do not have a melting point are preferable. As polysaccharides, especially from the viewpoint of obtaining excellent capacity, electrical resistance, and recovery rate, or from the viewpoint of not having a melting point and obtaining, more preferably cellulose and its analogs, including a cross-linked structure Polysaccharides (for example, starch containing cross-linked structure, etc.). The crosslinked structure is not limited to the following, but examples include ester crosslinks, phosphoric acid crosslinks, acetal crosslinks, ether crosslinks, and the like. From the viewpoint that the thermal decomposition temperature is higher than the melting point of polysaccharides, ester crosslinking and ether crosslinking are particularly preferred.

These sugars can be used individually or in combination of 2 or more types.

First, the manufacturing method of the carbonaceous material of the present invention including steps (1), (2A), (2B), (3A), and (3B) will be explained. Step (1) is a step of heat-treating the raw material of the carbon precursor at a temperature range of 215-240° C. for 1-12 hours under the supply of oxygen-containing gas to obtain the carbon precursor. The oxygen-containing gas is not particularly limited as long as it is a gas containing oxygen, and it may be air, oxygen, or a mixed gas of air or oxygen and other gases such as inert gas. The oxygen concentration in the oxygen-containing gas is also not particularly limited. From the viewpoint of easy implementation of this step and reduction of manufacturing cost, the oxygen-containing gas is preferably air.

The heat treatment performed under the supply of oxygen-containing gas means that the heat treatment is performed while supplying the oxygen-containing gas. Here, for example, heat treatment only in an atmosphere of oxygen-containing gas such as air, such as heat treatment only in an atmosphere, cannot be said to be actively supplying oxygen-containing gas, and cannot be said to be under the supply of oxygen-containing gas Perform heat treatment. Therefore, such a step does not correspond to step (1) in the manufacturing method of the present invention. In step (1), the supply amount of oxygen-containing gas is not particularly limited as long as it is supplied. For example, per unit surface area of the raw material of the carbon precursor, it is preferably 0.007-3.0L/(min･m ² ), More preferably, it is 0.009 to 2.0L/(minute･m ² ), and still more preferably 0.01 to 0.50L/(minute･m ² ). In addition, the supply amount per unit surface area is, for example, the supply amount of oxygen-containing gas per minute divided by the product of the weight of the object to be processed (raw material, carbon precursor, or carbide) and the specific surface area And figure it out.

Here, in step (1), it is considered that while the physically adsorbed water contained in the raw material of the carbon precursor is dried by heat treatment, a molecular-level dehydration reaction occurs in the raw material of the carbon precursor to obtain the carbon precursor Things. By performing this step under the supply of oxygen-containing gas, the mechanism described below does not limit the present invention in any way, but when water is removed from the raw material of the carbon precursor by drying and dehydration, the supplied oxygen and the raw material of the carbon precursor Interaction, and the removed water is removed from the system together with the gas. As a result, it is considered that the raw material of the carbon precursor does not melt due to the heat treatment, and a carbon precursor with a fine structure can be obtained.

In step (1), the temperature of the raw material is raised, as described above, and the heat treatment is performed in the temperature range of 215 to 240°C for 1 to 12 hours. The heat treatment temperature in step (1) is preferably 217 to 235°C, more preferably 219 to 230°C. The heat treatment time is preferably 2 to 8 hours, more preferably 2.5 to 6 hours, and still more preferably 3 to 5 hours. It is believed that as long as the heat treatment temperature and time are within the above range, water can be efficiently and sufficiently removed from the raw material of the carbon precursor by drying and dehydration, and finally, a carbonaceous material with the above characteristics can be easily obtained. Here, the heat treatment temperature may be a certain temperature, but it is not particularly limited as long as it is within the above-mentioned range.

Step (2A) is a step of heating the carbon precursor obtained in step (1) to the first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment. (2B) is a step of heat-treating the carbon precursor at a temperature of 500 to 900° C. under the supply of an inert gas to obtain a carbide. Step (2A) is carried out in an inert gas environment, step (2B) is carried out under the supply of inert gas, and the amount of inert gas supplied in step (2B) is per unit surface area of the carbon precursor The medium is 0.01～5.0L/(minute･m ² ). Here, the step is performed in an inert gas environment, which means that the step is performed in an inert gas environment, and the active supply of inert gas may or may not be performed. In contrast, the so-called step performed under the supply of inert gas means that it is performed under an environment where inert gas is supplied. For example, heat treatment only under an environment of inert gas cannot be said to be actively performing inert gas. It cannot be said that the heat treatment is performed under the supply of inert gas. In addition, in this specification, this step (2A) and/or (2B) is also referred to as low-temperature sintering (step). Examples of the inert gas include argon, helium, and nitrogen, and nitrogen is preferred.

The heating rate in step (2A) is from the viewpoint that it is easy to obtain the carbonaceous material with the above-mentioned characteristics in the end, especially from the viewpoint that it is easy to adjust the nitrogen atom content and the half-value width of the Raman peak near 1360 cm ^-1 to within the above-mentioned range From a viewpoint, it is preferably at least 100°C/hour, more preferably at least 300°C/hour, still more preferably at least 400°C/hour, and particularly preferably at least 500°C/hour. The upper limit of the temperature increase rate is not particularly limited. From the viewpoint of easily suppressing the increase in the specific surface area due to rapid thermal decomposition, it is preferably 1000°C/hour or less, and more preferably 800°C/hour or less. The first temperature in step (2A) is 500-900°C, preferably 550-880°C, more preferably 600-860°C, and still more preferably 700-840°C.

Next, in step (2B), under the supply of an inert gas, the carbon precursor is heat-treated at a temperature of 500 to 900° C. to obtain carbides. Hereinafter, the heat treatment temperature in step (2B) is also referred to as the low-temperature sintering temperature. The low-temperature sintering temperature in step (2B) is 500-900°C, preferably 550-880°C, more preferably 600-860°C, still more preferably 700-840°C. As long as the low-temperature sintering temperature is within the above-mentioned range, the carbonaceous material with the above-mentioned characteristics will be easily obtained in the end. The low-temperature sintering temperature may be a certain temperature, but it is not particularly limited as long as it is within the above-mentioned range. The supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of the carbon precursor, preferably 0.015～4.0L/(minute･m ² ), more preferably 0.020 ～3.0L/(minute･m ² ). Step (2A) is also preferably performed while supplying the inert gas with the above-mentioned inert gas supply amount. In addition, from the viewpoint of facilitating easy operation, the first temperature in step (2A) and the heat treatment temperature in step (2B) are preferably equal. The heat treatment time in step (2B) is preferably 0.1 to 5 hours, more preferably 0.3 to 3 hours, and still more preferably 0.5 to 2 hours.

Step (3A) is a step of heating the carbide obtained in step (2B) to a second temperature in the range of 1000 to 1400°C at a temperature increase rate of 100°C/hour or more in an inert gas environment, step ( 3B) is a step of heat-treating the carbide at a temperature of 1000 to 1400° C. under the supply of an inert gas to obtain a carbonaceous material. Here, step (3A) is carried out in an inert gas environment, step (3B) is carried out under the supply of inert gas, and the supply amount of inert gas in step (3B) is based on each carbon precursor. 0.01～5.0L/(minute･m ² ) per unit surface area. Here, the conditions under the inert gas environment and the inert gas supply are as described for (2A) and (2B) above. In addition, in this specification, this step (3A) and/or (3B) is also referred to as high-temperature sintering (step). Examples of the inert gas include those described above for (2A) and (2B), and nitrogen is preferred.

The temperature increase rate in step (3A) is from the viewpoint that it is easy to finally obtain a carbonaceous material with the above characteristics, and in particular, it is easy to adjust the nitrogen atom content and the half-value width of the Raman peak near 1360 cm ^-1 within the above-mentioned range In view of this, it is preferably 100°C/hour or higher, more preferably 300°C/hour or higher, still more preferably 400°C/hour or higher, and particularly preferably 500°C/hour or higher. The upper limit of the heating rate is not particularly limited. From the viewpoint of easily suppressing the increase in specific surface area due to rapid thermal decomposition, it is preferably 800°C/hour or less, more preferably 700°C/hour or less, and even more preferably Below 600°C/hour. The second temperature in step (3A) is 1000 to 1400°C, preferably 1050 to 1380°C, more preferably 1100 to 1370°C, still more preferably 1150 to 1360°C, particularly preferably 1200 to 1350°C.

From the viewpoint of making a structure that can easily occlude lithium ions and increasing the discharge capacity, step (3A) is usually performed after step (2B). Therefore, the temperature raising step in the step (3A) is a step of raising the temperature from the low-temperature sintering temperature in the range of 500 to 900°C to the second temperature in the range of 1000 to 1400°C. For example, at the above-mentioned heating rate, the temperature is increased from the low-temperature sintering temperature (500-900℃) to the second temperature (1000-1400℃), preferably from the low-temperature sintering temperature (550-880℃) to the second temperature (1050 ～1380℃), more preferably from the low temperature sintering temperature (600～860℃) to the second temperature (1100～1370℃), still more preferably from the low temperature sintering temperature (600～860℃) to the second temperature ( 1150 to 1360°C), particularly preferably from the low temperature sintering temperature (700 to 840°C) to the second temperature (1200 to 1350°C).

Next, in step (3B), under the supply of an inert gas, the carbide is heat-treated at a temperature of 1000 to 1400° C. to obtain a carbonaceous material. Hereinafter, the heat treatment temperature in step (3B) is also referred to as the high temperature sintering temperature. The high-temperature sintering temperature in step (3B) is 1000 to 1400°C, preferably 1050 to 1380°C, and more preferably 1100 to 1400°C, from the viewpoint of easy operation and easy operation and finally easy obtaining of the carbonaceous material with the above characteristics. 1370°C, more preferably 1150-1360°C, particularly preferably 1200-1350°C. The high-temperature sintering temperature may be a certain temperature, but it is not particularly limited as long as it is within the above-mentioned range. The heat treatment time in step (3B) is preferably 0.1 to 5 hours, more preferably 0.3 to 3 hours, and still more preferably 0.5 to 2 hours. The supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of the carbide, preferably 0.015～4.0L/(minute･m ² ), more preferably 0.020～ 3.0L/(minute･m ² ). Step (3A) is also preferably performed while supplying the inert gas at the above-mentioned inert gas supply amount. In addition, from the viewpoint of facilitating easy operation, the second temperature in step (3A) and the heat treatment temperature in step (3B) are preferably equal.

The high-temperature sintering temperature (that is, the sintering temperature in step (3B)) is preferably equal to the second temperature in the above step (3A), since it is easily available to provide high charge and discharge capacity and charge and discharge efficiency and low resistance when used in electrodes From the viewpoint of the carbonaceous material, the sintering temperature in step (2B) is preferable (in a preferable aspect, it is the first temperature in step (2A)) or higher. The high-temperature sintering temperature is preferably 50-700℃ higher than the low-temperature sintering temperature, more preferably 100-600℃ higher, still more preferably 150-500℃ higher, particularly preferably 200-400 higher ℃ temperature.

The manufacturing method of the carbonaceous material of the present invention may further include adding at least one volatile organic compound to the carbide obtained in step (2B) before the step (3A) and (3B) of sintering the carbide at high temperature的步骤(10). By performing step (10), the organic matter volatilized during carbide sintering at high temperature adheres to the surface of the carbide. As a result, on the one hand, it maintains the correlation with the above-mentioned nitrogen atom content and the half-value width of the Raman peak near 1360cm ^-1 On the one hand, it becomes easier to manufacture carbonaceous materials with lower specific surface area. Such a carbonaceous material maintains high charge and discharge capacity and charge and discharge efficiency, while reducing the amount of water present in the carbonaceous material, thereby suppressing the hydrolysis of the electrolyte and the electrolysis of water caused by the moisture.

Volatile organic compounds are hardly carbonized (for example, preferably 80% or more of the substance, more preferably 90% or more non-carbonized) when heat treatment is performed at a temperature of 500°C or higher in an inert gas environment such as nitrogen. Organic compounds that volatilize (vaporize or thermally decompose to become a gas). The volatile organic compounds are not limited to those described below, but examples include thermoplastic resins and low molecular weight organic compounds. Examples of thermoplastic resins include polystyrene, polyethylene, polypropylene, poly(meth)acrylic acid, and poly(meth)acrylate. In addition, in this specification, (meth)acrylic methacrylic acid and acrylic acid are collectively referred to. Examples of the low-molecular organic compound include toluene, xylene, 1,3,5-trimethylbenzene, styrene, naphthalene, phenanthrene, anthracene, pyrene, and the like. Since it is volatilized and thermally decomposed at the sintering temperature, it is preferably one that does not oxidize and activate the surface of the carbon precursor. Therefore, the thermoplastic resin is preferably polystyrene, polyethylene, or polypropylene. As the low-molecular organic compound, from the viewpoint of safety, it is more preferable to be a compound having low volatility at room temperature (for example, 20°C), and particularly preferable are naphthalene, phenanthrene, anthracene, pyrene, etc.

In step (10), at least one volatile organic compound is added to the carbide obtained in step (2B). The addition method is not particularly limited. For example, the carbide obtained in step (2B) and at least one volatile organic compound can be mixed and added. The addition amount of the volatile organic compound is not particularly limited, and relative to 100 parts by mass of the carbide, it is preferably 2-30 parts by mass, more preferably 4-20 parts by mass, and still more preferably 5-15 parts by mass.

The manufacturing method of the carbonaceous material of the present invention may further include the step (11) of pulverizing the carbon precursor, carbide and/or carbonaceous material. The pulverization step (11) is performed on the carbon precursor, carbide, and/or carbonaceous material by a usual method, such as a method using a ball mill or a jet mill. The pulverization step (11) can be carried out after the steps (1), (2B) and/or (3B), for example. From the viewpoint of less prone to shrinkage and shape change due to heat treatment, the step (2B) is preferred. Or (3B) afterwards.

Next, the manufacturing method of the carbonaceous material of the present invention including steps (4), (5A), (5B), (6A), and (6B) will be described. Step (4) is a step of mixing the raw material of the carbon precursor with 1-20 parts by mass of at least one organic acid with respect to 100 parts by mass of the raw material to obtain a mixture. The organic acid is not particularly limited, and examples include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, nonanoic acid, capric acid, undecanoic acid, palmitic acid, stearic acid, Aliphatic carboxylic acids such as succinic acid, linoleic acid, and octadecenoic acid; aromatic carboxylic acids such as benzoic acid, salicylic acid, and phthalic acid; hydroxycarboxylic acids such as lactic acid, tartaric acid, citric acid, and malic acid; Carboxylic acids such as diaminetetraacetic acid, and sulfonic acids such as p-toluenesulfonic acid and methanesulfonic acid. From the standpoint that it is easy to add a small amount to obtain the effect of forming a crosslinked structure, the organic acid is preferably a strong acid, and more preferably a sulfonic acid.

The amount of organic acid mixed with the raw material of the carbon precursor in step (4) is less likely to hinder the formation of the carbon structure in the subsequent heat treatment due to excessive crosslinking, relative to 100 parts by mass of the raw material of the carbon precursor, It is 1-20 parts by mass, preferably 1.5-15 parts by mass, more preferably 2-10 parts by mass. The method of mixing the raw material of the carbon precursor and the organic acid is not particularly limited. The raw material of the carbon precursor and the organic acid may be directly mixed, or the carbon precursor and/or organic acid may be dispersed and/or dissolved in at least 1 Mix in a liquid state. In addition, when at least one liquid is used for mixing, it is also possible to obtain a mixture by removing the liquid by evaporation or the like as required. From the viewpoint of easily obtaining a homogeneous mixture, it is preferable to dissolve at least one organic acid in at least one liquid in a solution, add the raw material of the carbon precursor to mix, and then distill the liquid away. Get a mixture.

Step (5A) is a step of heating the mixture obtained in step (4) to the first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment. Step (5B ) Is a step of heat-treating the mixture at a temperature of 500 to 900°C under the supply of an inert gas to obtain a carbide. Steps (5A) and (5B) are equivalent to the steps (2A) and (2B) above except that the mixture obtained in step (4) is used instead of the carbon precursor obtained in step (1). The contents described in steps (2A) and (2B). In addition, in steps (2A) and (2B), the description related to the supply amount of inert gas per unit surface area of the carbon precursor is related to steps (5A) and (5B). The carbon precursor contained is related to the supply per unit surface area.

It is considered here that in steps (4), (5A) and (5B), the cross-linked structure is formed due to the catalytic action of the acid during the heating process. As a result, it is considered that the raw material of the carbon precursor does not melt due to heat treatment, and a carbon precursor with a fine structure can be obtained.

Step (6A) is a step of heating the carbide obtained in step (5B) to a second temperature in the range of 1000 to 1400°C at a temperature increase rate of 100°C/hour or more in an inert gas environment, step ( 6B) is a step of heat-treating the carbide at a temperature of 1000 to 1400° C. under the supply of an inert gas to obtain a carbonaceous material. Steps (6A) and (6B) are equivalent to steps (3A) and (3B) except that the carbide obtained in step (5B) is used instead of the carbide obtained in step (2B). The same applies to the above for (3A) and (3B) Contents recorded. In addition, the steps (10) and (11) are also applicable to this embodiment.

Furthermore, the manufacturing method of the carbonaceous material of the present invention including steps (7), (8A), (8B), (9A), and (9B) will be described. Step (7) is to heat the mixture obtained by mixing the raw material of the carbon precursor with at least one heat-resistant oil of 80-500 parts by mass relative to 50 parts by mass of the raw material in the temperature range of 150-300°C for 0.5-12 Hours to obtain the carbon precursor. The heat-resistant oil is not particularly limited, as long as it does not volatilize or deteriorate at least in the heat treatment temperature range. Examples include silicone oil, fluorine oil, creosote oil, diethylene glycol, and triethylene glycol. Alcohol, polyethylene glycol, etc.

The amount of heat-resistant oil mixed with the raw material of the carbon precursor is 80 to 500 parts by mass, preferably 100 to 50 parts by mass relative to 50 parts by mass of the raw material of the carbon precursor, from the viewpoint of dispersing the raw material and preventing welding. 400 parts by mass, more preferably 150 to 300 parts by mass, still more preferably 180 to 280 parts by mass. The method of mixing the raw material of the carbon precursor and the heat-resistant oil is not particularly limited. The raw material of the carbon precursor and the heat-resistant oil may be directly mixed, or the carbon precursor and/or organic acid may be dispersed and/or dissolved in Mix at least one type of liquid. In addition, when at least one liquid is used for mixing, it is also possible to obtain a mixture by removing the liquid by evaporation or the like as required.

It is considered here that in step (7), the physically adsorbed water contained in the raw material of the carbon precursor is dried by heat treatment, and a molecular-level dehydration reaction occurs in the raw material of the carbon precursor to obtain the carbon precursor. By performing this step in a state of being mixed with heat-resistant oil, the mechanism described below does not limit the present invention in any way. However, water produced from the raw material of the carbon precursor due to drying and dehydration is considered to be caused by the presence of heat-resistant oil. It is efficiently removed from the carbon precursor surface. As a result, it is considered that the raw material of the carbon precursor does not melt due to the heat treatment, and a carbon precursor with a fine structure can be obtained.

In step (7), the mixture obtained by mixing the raw material of the carbon precursor and the heat-resistant oil is heat-treated at a temperature range of 50 to 300° C. for 0.5 to 12 hours to obtain the carbon precursor. The heat treatment temperature in step (7) is 50-300°C, preferably 150-300°C, more preferably 180-280°C, still more preferably 200-260°C, particularly preferably 210-250°C. The heat treatment time is 0.5 to 12 hours, preferably 1 to 8 hours, more preferably 2 to 6 hours, still more preferably 3 to 5 hours. If the heat treatment temperature and time are within the above range, it is considered that it is easy to efficiently and fully remove water from the raw material of the carbon precursor by drying and dehydration, and finally, it is easy to obtain a carbonaceous material having the above characteristics. Here, the heat treatment temperature may be a certain temperature, but it is not particularly limited as long as it is within the above-mentioned range.

Step (8A) is a step of heating the carbon precursor obtained in step (7) to the first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment. (8B) is a step of heat-treating the carbon precursor at a temperature of 500 to 900° C. under the supply of an inert gas to obtain a carbide. Steps (8A) and (8B) are equivalent to the steps (2A) and (2B) above except that the carbon precursor obtained in step (7) is used instead of the carbon precursor obtained in step (1). The above refers to the content described in steps (2A) and (2B).

Step (9A) is a step of heating the carbide obtained in step (8B) to a second temperature in the range of 1000 to 1400°C at a temperature increase rate of 100°C/hour or more in an inert gas environment, step ( 9B) is a step of heat-treating the carbide at a temperature of 1000 to 1400°C under the supply of an inert gas to obtain a carbonaceous material. Steps (9A) and (9B) are equivalent to steps (3A) and (3B) except that the carbide obtained in step (8B) is used instead of the carbide obtained in step (2B). The same applies to (3A) And the content recorded in (3B). In addition, the steps (10) and (11) are also applicable to this embodiment.

In still another aspect of the present invention, the carbonaceous material of this embodiment, more specifically the method for manufacturing the carbonaceous material for non-aqueous electrolyte secondary batteries, includes: (12A) In an inert gas environment, The step of heating the polysaccharide to the first temperature in the range of 500-900°C at a temperature increase rate of 100°C/hour or more; (12B) The polysaccharide is heated at a temperature of 500-900°C under the supply of inert gas The step of heat treatment to obtain carbides; here, the supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of polysaccharide; (13A) In a gas environment, the step of heating the carbide to a second temperature in the range of 1000 to 1600°C at a temperature increase rate of 100°C/hour or more; and (13B) under the supply of inert gas, at 1000 to 1600°C The step of heat-treating the carbide at a temperature to obtain a carbonaceous material; here, the supply amount of inert gas is 0.01-5.0L/(min･m ² ) per unit surface area of the carbide.

The carbonaceous material of this embodiment is preferably derived from a substance having a saccharide skeleton, and examples of the substance having a saccharide skeleton include polysaccharides. The polysaccharides used in the above step (12A) are not particularly limited as long as they are polysaccharides that form the carbonaceous material of the present invention through steps such as subsequent heat treatment. Examples include starch; glycogen; agarose; pectin; cellulose and the like. Examples of cellulose analogs include those substituted with functional groups for the hydroxyl groups of cellulose. Examples include acetyl cellulose (substituting some or all of the hydroxyl groups with acetyl groups), and chitin (with acetyl acetone). The amine group replaces the hydroxyl group at the second position), chitosan (the amine group replaces the hydroxyl group at the second position), etc. These polysaccharides can be used individually or in combination of 2 or more types. Among these polysaccharides, from the viewpoint of obtaining carbonaceous materials more easily, or from the viewpoint of simplifying the steps and increasing the recovery rate by omitting the crushing and classification steps, the polysaccharides that do not have a melting point are preferred. carbohydrate. By using polysaccharides that do not have melting points, carbonaceous materials derived from polysaccharides that do not have melting points can be obtained. Here, the term “not having a melting point” means that when TG-DTA is measured, it does not have the endothermic peak of DTA in the range of room temperature (for example, 20°C) to 400°C. As polysaccharides, especially from the viewpoint of obtaining excellent capacity, electrical resistance, and recovery rate, or from the viewpoint of not having a melting point and obtaining, more preferably cellulose and its analogs, including a cross-linked structure Polysaccharides (for example, starch containing cross-linked structure, etc.). Although the crosslinking structure is not limited to the following, examples thereof include ester crosslinking, phosphoric acid crosslinking, acetal crosslinking, and ether crosslinking. From the viewpoint that the thermal decomposition temperature is higher than the melting point of polysaccharides, ester crosslinking and ether crosslinking are particularly preferred.

Here, steps (12A), (12B), (13A), and (13B) correspond to steps (2A), (2B), (3A), and (3B), respectively. By using polysaccharides as the carbon precursor, the carbonaceous material of the present invention can be obtained even if the step (1) before step (2A) is not carried out.

Step (12A) is a step of heating polysaccharides to the first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment. Step (12B) is followed by Under the supply of gas, the polysaccharide is heat-treated at a temperature of 500 to 900°C to obtain a carbide. In addition, in this specification, this step (12A) and/or (12B) is also referred to as low-temperature sintering (step). The supply amount of the inert gas in step (12A) is 0.01 to 5.0L/(minute･m ² ) per unit surface area of the polysaccharide, preferably 0.015 to 4.0L/(minute･m ² ) , More preferably 0.020～3.0L/(minute･m ² ). Step (12A) is also preferably performed while supplying the inert gas with the above-mentioned inert gas supply amount. If the supply amount of inert gas is less than 0.01L/(minute･m ² ), moisture and thermal decomposition products generated from polysaccharides will stay, which may lead to welding and foaming, and the process may not be simplified. If the supply amount of inert gas exceeds 3.0L/(minute･m ² ), the carbon precursor may scatter and the recovery rate may decrease. Examples of the inert gas include argon, helium, and nitrogen, and nitrogen is preferred.

The rate of temperature increase in step (12A), from the standpoint of obtaining a carbonaceous material with the above characteristics, is preferably 100°C/hour or more, more preferably 300°C/hour or more, and still more preferably 400°C/hour Above, 500°C/hour or more is particularly preferred. The upper limit of the temperature increase rate is not particularly limited. From the viewpoint of easily suppressing the increase in the specific surface area due to rapid thermal decomposition, it is preferably 1000°C/hour or less, and more preferably 800°C/hour or less. The first temperature in step (12A) is 500 to 900°C, preferably 550 to 880°C, more preferably 600 to 860°C, and still more preferably 700 to 840°C.

Next, in step (12B), under the supply of inert gas, the polysaccharides that have passed through this step (12A) are heat-treated at a temperature of 500 to 900°C to obtain carbides. Hereinafter, the heat treatment temperature in step (12B) is also referred to as the low-temperature sintering temperature. The low-temperature sintering temperature in step (12B) is 500-900°C, preferably 550-880°C, more preferably 600-860°C, and still more preferably 700-840°C. As long as the low-temperature sintering temperature is within the above range, it is easy to finally obtain a carbonaceous material with the above characteristics. The low-temperature sintering temperature may be a certain temperature, but it is not particularly limited as long as it is within the above-mentioned range. The supply amount of inert gas is 0.01～5.0L/(min･m ² ) per unit surface area of polysaccharide, preferably 0.015～4.0L/(min･m ² ), more preferably 0.020 ～3.0L/(minute･m ² ). In addition, from the viewpoint of facilitating easy operation, the first temperature in step (12A) and the heat treatment temperature in step (12B) are preferably equal to the supply amount of inert gas. The heat treatment time in step (12B) is preferably 0.1 to 5 hours, more preferably 0.3 to 3 hours, and still more preferably 0.5 to 2 hours.

Step (13A) is a step of heating the carbide obtained in step (12B) to a second temperature in the range of 1000 to 1600°C at a temperature increase rate of 100°C/hour or more under an inert gas environment, step ( 13B) is a step of heat-treating the carbide at a temperature of 1000 to 1600°C under the supply of an inert gas to obtain a carbonaceous material. Here, step (13A) is performed in an inert gas environment, step (13B) is performed under the supply of inert gas, and the supply amount of inert gas in step (13B) is based on each carbon precursor. 0.01～5.0L/(minute･m ² ) per unit surface area. Here, the conditions under the inert gas environment and the inert gas supply are as described for (12A) and (12B) above. In addition, in this specification, this step (13A) and/or (13B) is also referred to as high-temperature sintering (step). Examples of the inert gas include those described above for (12A) and (12B), and nitrogen is preferred.

The rate of temperature increase in step (13A), from the standpoint that it is easy to finally obtain a carbonaceous material with the above characteristics, is preferably at least 100°C/hour, more preferably at least 300°C/hour, and still more preferably 400°C/hour Above, 500°C/hour or more is particularly preferred. The upper limit of the heating rate is not particularly limited. From the viewpoint of easily suppressing the increase in specific surface area due to rapid thermal decomposition, it is preferably 800°C/hour or less, more preferably 700°C/hour or less, and even more preferably Below 600°C/hour. The second temperature in step (13A) is 1000 to 1600°C, preferably 1050 to 1500°C, more preferably 1100 to 1400°C, and still more preferably 1200 to 1350°C.

From the viewpoint of making a structure that can easily store lithium ions and increasing the discharge capacity, step (13A) is usually followed by step (12B). Therefore, the temperature raising step in the step (13A) is a step of raising the temperature from the low-temperature sintering temperature in the range of 500 to 900°C to the second temperature in the range of 1000 to 1600°C. For example, at the above-mentioned heating rate, the temperature is increased from the low-temperature sintering temperature (500-900°C) to the second temperature (1000-1600°C), preferably from the low-temperature sintering temperature (550-880°C) to the second temperature (1050 ～1500℃), more preferably from the low temperature sintering temperature (600～860℃) to the second temperature (1100～14000℃), still more preferably from the low temperature sintering temperature (700～840℃) to the second temperature ( 1200～1350℃).

Next, in step (13B), under the supply of an inert gas, the carbide is heat-treated at a temperature of 1000 to 1600°C to obtain a carbonaceous material. Hereinafter, the heat treatment temperature in step (13B) is also referred to as the high-temperature sintering temperature. The high-temperature sintering temperature in step (13B) is 1000 to 1600°C, preferably 1050 to 1500°C, and more preferably 1100 to 1100°C, from the standpoint of making the operation easy and finally obtaining a carbonaceous material with the above characteristics. 1400℃, more preferably 1200～1350℃. The high-temperature sintering temperature may be a certain temperature, but it is not particularly limited as long as it is within the above-mentioned range. The heat treatment time in step (13B) is preferably 0.1 to 5 hours, more preferably 0.3 to 3 hours, and still more preferably 0.5 to 2 hours. The supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of the carbide, preferably 0.015～4.0L/(minute･m ² ), more preferably 0.020～ 3.0L/(minute･m ² ). Step (13A) is also preferably performed while supplying the inert gas at the above-mentioned inert gas supply amount. In addition, from the viewpoint of facilitating easy operation, the second temperature in step (13A) and the heat treatment temperature in step (13B) are preferably equal.

The high-temperature sintering temperature (that is, the sintering temperature in step (13B)) is preferably equal to the second temperature in the above step (13A), since it is easily available to provide high charge and discharge capacity and charge and discharge efficiency and low resistance when used in electrodes From the point of view of the carbonaceous material, the sintering temperature in step (12B) is preferable (in a preferred aspect, it is the first temperature in step (12A)) or higher. The high-temperature sintering temperature is preferably 50-700℃ higher than the low-temperature sintering temperature, more preferably 100-600℃ higher, still more preferably 150-500℃ higher, particularly preferably 200-400 higher ℃ temperature.

The manufacturing method of the carbonaceous material of the present invention may further include adding at least one volatile organic compound to the carbide obtained in step (12B) before the step (13A) and (13B) of sintering the carbide at high temperature的 step (14). By proceeding to step (14), the organic matter volatilized during carbide sintering is attached to the surface of the carbide at a high temperature. As a result, on the one hand, the characteristics of the carbonaceous material of the present invention can be maintained, and on the other hand, it becomes easier to manufacture with lower Carbonaceous material with specific surface area. Such a carbonaceous material maintains high charge and discharge capacity and charge and discharge efficiency, while reducing the amount of moisture present in the carbonaceous material, thereby inhibiting the hydrolysis of the electrolyte and the electrolysis of water caused by the moisture.

Volatile organic compounds are hardly carbonized under inert gas environment such as nitrogen, for example, at a temperature of 500°C or higher (for example, preferably 80% or more of the substance, more preferably 90% or more non-carbonized ) And volatilized (vaporized or thermally decomposed to become a gas) organic compound. The volatile organic compounds are not limited to the following, but examples include thermoplastic resins, low molecular weight organic compounds, and organic acids. Examples of thermoplastic resins include polystyrene, polyethylene, polypropylene, poly(meth)acrylic acid, and poly(meth)acrylate. In addition, in this specification, (meth)acrylic methacrylic acid and acrylic acid are collectively referred to. Examples of the low-molecular organic compound include toluene, xylene, 1,3,5-trimethylbenzene, styrene, naphthalene, phenanthrene, anthracene, pyrene, and the like. The organic acid is not particularly limited, and carboxylic acids such as citric acid, fumaric acid, malic acid, and maleic acid can be cited. Since it is volatilized and thermally decomposed at the sintering temperature, it is preferably one that does not oxidize and activate the surface of the carbon precursor. Therefore, the thermoplastic resin is preferably polystyrene, polyethylene, or polypropylene. As the low-molecular-weight organic compound, from the viewpoint of safety, compounds having low volatility at room temperature (for example, 20°C) are more preferable, and naphthalene, phenanthrene, anthracene, pyrene, etc. are particularly preferable.

In step (14), at least one volatile organic compound is added to the carbide obtained in step (12B). The addition method is not particularly limited. For example, the carbide obtained in step (12B) and at least one volatile organic compound may be mixed and added. The addition amount of the volatile organic compound is not particularly limited, and relative to 100 parts by mass of the carbide, it is preferably 2-30 parts by mass, more preferably 4-20 parts by mass, and still more preferably 5-15 parts by mass.

The manufacturing method of the carbonaceous material of the present invention may further include the step (15) of pulverizing and classifying the carbide and/or carbonaceous material. The pulverization and classification step (15) is carried out for polysaccharides, carbides and/or carbonaceous materials by a usual method, such as a method using a ball mill or a jet mill. The pulverization and classification step (15), for example, can be carried out after step (12B) and/or (13B), but because polysaccharides do not have a melting point, they will not melt in step (12B), so from simplifying the steps and improving recovery From the viewpoint of rate, it is better to omit.

According to the present invention, carbides can also be obtained as intermediates in the production of carbonaceous materials. The carbide can be produced by, for example, a carbide manufacturing method that includes at least the steps (1), (2A), and (2B), and a carbide that includes at least the steps (4), (5A), and (5B). The method of manufacturing, or the method of manufacturing carbide at least including the steps (7), (8A) and (8B) above. The manufacturing method of carbide may preferably also include the above-mentioned crushing step (11) after step (2B), (5B) or (8B). Alternatively, the carbide can also be obtained by, for example, a method for producing a carbide including at least the steps (12A) and (12B). The production method may preferably include the above-mentioned pulverization and classification after step (12B). Step (15). For example, the carbide produced as described above can also be used as a carbonaceous material suitable for producing a negative electrode active material for a non-aqueous electrolyte secondary battery with high charge and discharge capacity and charge and discharge efficiency and preferably low resistance. The present invention also provides carbides used as intermediates in the manufacture of carbonaceous materials and a method for manufacturing the carbides.

In the carbide, the nitrogen atom content obtained by elemental analysis is preferably 0.20 mass% or more, more preferably 0.20 mass% or more, still more preferably 0.30 mass% or more, still more preferably 0.35 mass% or more, particularly preferably 0.40% by mass or more. Moreover, the nitrogen atom content is preferably 0.90 mass% or less, more preferably 0.85 mass% or less, still more preferably 0.80 mass% or less, still more preferably 0.75 mass% or less, particularly preferably 0.70 mass% or less. When the content of nitrogen atoms in the carbide is within the above range, it is easy to adjust the content of nitrogen atoms in the carbonaceous material made from the carbide within the range described above for the carbonaceous material, and it is easy to improve the non-aqueous electrolyte. The charge-discharge capacity and charge-discharge efficiency of the secondary battery. The nitrogen atom content of carbides can also be measured in the same manner as described for carbonaceous materials.

In the carbide, the oxygen atom content obtained by elemental analysis is preferably 2.0% by mass or more, more preferably 2.2% by mass or more, still more preferably 2.5% by mass or more, still more preferably 2.7% by mass or more, and particularly preferably 3.0% by mass or more. In addition, the oxygen atom content is preferably 7.0% by mass or less, more preferably 6.7% by mass or less, still more preferably 6.5% by mass or less, still more preferably 6.3% by mass or less, and particularly preferably 6.0% by mass or less. In addition, the oxygen atom content, which is the same as the nitrogen atom content in carbonaceous materials, can be measured by elemental analysis.

In the carbide, the hydrogen atom content obtained by elemental analysis is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, still more preferably 1.6% by mass or more, still more preferably 1.8% by mass or more, and particularly preferably 2.0% by mass or more. In addition, the hydrogen atom content is preferably 4.0% by mass or less, more preferably 3.7% by mass or less, still more preferably 3.4% by mass or less, still more preferably 3.2% by mass or less, still more preferably 3.0% by mass or less, particularly preferred It is 2.8% by mass or less. In addition, the content of hydrogen atoms, which is the same as the content of nitrogen atoms in carbonaceous materials, can be measured by elemental analysis.

1360cm half width of the peak value of the carbides in the vicinity of ^-1, the Raman laser Raman spectroscopy to the observed spectrum is preferably 250cm ^-1 or more, more preferably 255 cm ^-1 or more, and still more preferably It is 260 cm ^-1 or more, particularly preferably 265 cm ^-1 or more. In addition, the half-value width is preferably 300 cm ^-1 or less, more preferably 295 cm ^-1 or less, and still more preferably 290 cm ^-1 or less. When the half-value width of the carbide is within the above range, it is easy to adjust the half-value width of the carbonaceous material produced from the carbide within the range described above for the carbonaceous material, and it is easy to increase the non-aqueous electrolyte The charge and discharge capacity and efficiency of the secondary battery. The above-mentioned half-value width of carbides can be measured in the same manner as described for carbonaceous materials.

In this carbide, the intensity ratio (R value=I ₁₃₆₀ /I ₁₅₈₀ ) of the peak intensity (I ₁₃₆₀ ) near 1360 cm ^{-1 of the} Raman spectrum and the peak intensity (I ₁₅₈₀ ) near 1580 cm ^{-1 is} preferably 0.50 or more , More preferably 0.55 or more, still more preferably 0.60 or more, particularly preferably 0.65 or more. In addition, the strength ratio is preferably 1.00 or less, more preferably 0.97 or less, still more preferably 0.95 or less, particularly preferably 0.93 or less. When the R value in the carbide is within the above range, it is easy to adjust the R value in the carbonaceous material produced from the carbide within the range described above for the carbonaceous material, and it is easy to improve the non-aqueous electrolyte secondary The charge-discharge capacity and charge-discharge efficiency of the battery. The above-mentioned R value of carbide can be measured in the same manner as described for carbonaceous materials.

The carbides, obtained by the nitrogen adsorption BET specific surface area of preferably 520m ² / g or less, more preferably 510m ² / g or less, and then the best of 500m ² / g or less, and particularly preferably 490m ² / g or less. When the specific surface area is below the above upper limit, the moisture absorption of the finally obtained carbonaceous material is likely to decrease, and the amount of moisture present in the carbonaceous material is likely to decrease. As a result, the hydrolysis of the electrolyte and the electrolysis of water due to moisture are suppressed, and the generation of acids and gases accompanying these phenomena is easily suppressed. In addition, when the specific surface area is below the above upper limit, the contact area between air and the carbonaceous material is easily reduced, and the oxidation of the carbonaceous material itself is easily suppressed. The lower limit of the specific surface area of the carbide obtained by the nitrogen adsorption BET method is not particularly limited, but it is preferably 350 m ² /g or more, and more preferably 360 m ² /g or more. The specific surface area of the carbide obtained by the nitrogen adsorption BET method can be measured in the same way as the method described for the carbonaceous material.

Among the carbides, the true density (ρ _He ) obtained by the helium method is preferably 1.30 or more, more preferably 1.35 or more, still more preferably 1.40 or more, particularly preferably 1.43 or more. Furthermore, the true density is preferably 1.60 or less, more preferably 1.57 or less, still more preferably 1.55 or less, and particularly preferably 1.53 or less. When the true density of the carbide is within the above range, it is easy to adjust the true density of the carbonaceous material made from the carbide within the range described above for the carbonaceous material, and it is easy to improve the non-aqueous electrolyte secondary battery. The charge-discharge capacity and charge-discharge efficiency in The true density of carbides (ρ _He ) can be measured in the same way as described for carbonaceous materials.

In the carbide, the average particle diameter D _{50 is} preferably 5 μm or more, more preferably 7 μm or more, still more preferably 8 μm or more, still more preferably 9 μm or more, and particularly preferably 10 μm or more. In addition, the average particle size D _{50 is} preferably 30 μm or less, more preferably 25 μm or less, still more preferably 22 μm or less, and particularly preferably 20 μm or less. When the average particle size D _{50 of the} carbide is within the above range, it is easy to adjust the average particle size D _{50 of the} carbonaceous material made from the carbide within the range described above for the carbonaceous material, and it is easy to increase The charge-discharge capacity and charge-discharge efficiency of non-aqueous electrolyte secondary batteries. The average particle size D _{50 of} carbides can be measured in the same manner as described for carbonaceous materials.

Among the carbides, the carbon surface spacing d ₀₀₂ calculated using the Bragg formula obtained by the wide-angle X-ray diffraction method is preferably 3.70° or more, more preferably 3.73° or more, and still more preferably 3.75° or more. In addition, the carbon plane spacing d _{002 is} preferably 4.00° or less, more preferably 3.97° or less, and still more preferably 3.95° or less. When the carbon plane spacing d ₀₀₂ in the carbide is within the above range, it is easy to adjust the carbon plane spacing d ₀₀₂ in the carbonaceous material made from the carbide within the range described above for the carbonaceous material, and it is easy to increase The charge-discharge capacity and charge-discharge efficiency of non-aqueous electrolyte secondary batteries. The carbon plane spacing d _{002 of} carbide can be measured in the same manner as described for carbonaceous materials.

The carbonaceous material of the present invention or the carbonaceous material obtained by the production method of the present invention can be preferably used as a negative electrode active material of a non-aqueous electrolyte secondary battery. The present invention also provides a negative electrode for a non-aqueous electrolyte secondary battery containing the carbonaceous material of the present invention and a non-aqueous electrolyte secondary battery having the negative electrode.

Hereinafter, the method of manufacturing the negative electrode for the non-aqueous electrolyte secondary battery of the present invention will be specifically described. For the negative electrode of the present invention, for example, a binding agent (binder) is added to the carbonaceous material of the present invention, an appropriate solvent is added, and these are kneaded to prepare an electrode mixture. The obtained electrode mixture is applied to a current collector plate containing a metal plate and the like, dried and then press-molded, whereby the negative electrode for the non-aqueous electrolyte secondary battery of the present invention can be manufactured.

By using the carbonaceous material of the present invention, an electrode (negative electrode) with high conductivity can be produced even without adding a conductive auxiliary agent. Furthermore, for the purpose of imparting high conductivity, a conductive auxiliary agent can be added when preparing the electrode mixture according to needs. As the conductive auxiliary agent, conductive carbon black, vapor grown carbon fiber (VGCF), nanotube, etc. can be used. The amount of conductive auxiliary agent added varies according to the type of conductive auxiliary agent used, but if the added amount is too small, the expected conductivity may not be obtained, and if it is too large, the dispersion in the electrode mixture may deteriorate. From this point of view, the preferred ratio of the added conductive aid is 0.5-10% by mass (here, the amount of active material (carbonaceous material) + the amount of binder + the amount of conductive aid = 100% by mass), and more It is preferably 0.5 to 7 mass%, particularly preferably 0.5 to 5 mass%. As a binding agent, as long as the mixture of PVDF (polyvinylidene fluoride), polytetrafluoroethylene, SBR (styrene, butadiene, rubber) and CMC (carboxymethyl cellulose) does not interact with the electrolyte The responder is not particularly limited. Among them, the mixture of SBR and CMC is preferable because SBR and CMC attached to the surface of the active material will not hinder the movement of lithium ions, and can obtain good input/output characteristics. In order to dissolve aqueous latex such as SBR and CMC to form a slurry, it is preferable to use a polar solvent such as water, but it can also be used after dissolving a solvent latex such as PVDF in N-methylpyrrolidone or the like. If the addition amount of the binder is too large, the resistance of the resulting electrode will increase, and the internal resistance of the battery will therefore increase, which may result in degradation of battery characteristics. In addition, if the addition amount of the binder is too small, the binding between the particles of the negative electrode material and the current collector may become insufficient. The preferred addition amount of the bonding agent varies according to the type of bonding agent used, but for example, the bonding agent that uses water as a solvent is mostly used by mixing multiple bonding agents, such as a mixture of SBR and CMC. The total amount of all the adhesives used is preferably 0.5 to 5% by mass, more preferably 1 to 4% by mass. On the other hand, in the PVDF-based adhesive, 3 to 13% by mass is preferable, and 3 to 10% by mass is more preferable. In addition, the amount of the carbonaceous material of the present invention in the electrode mixture is preferably 80% by mass or more, and more preferably 90% by mass or more. In addition, the amount of the carbonaceous material of the present invention in the electrode mixture is preferably 100% by mass or less, and more preferably 97% by mass or less.

The electrode active material layer is basically formed on both sides of the current collector plate, but it can also be formed on one side according to requirements. The thicker the electrode active material layer is, the fewer current collector plates and separators can be satisfied, which is preferable for increasing the capacity. However, the wider the electrode area facing the opposite electrode, the more advantageous the improvement of the input/output characteristics. Therefore, if the electrode active material layer is too thick, the input/output characteristics may decrease. From the viewpoint of the output when the battery is discharged, the thickness of the active material layer (per single side) is preferably 10 to 80 μm, more preferably 20 to 75 μm, and still more preferably 30 to 75 μm.

The non-aqueous electrolyte secondary battery of the present invention includes the negative electrode for a non-aqueous electrolyte secondary battery of the present invention. A non-aqueous electrolyte secondary battery having a negative electrode for a non-aqueous electrolyte secondary battery containing the carbonaceous material of the present invention has high charge and discharge capacity and charge and discharge efficiency.

When using the carbonaceous material of the present invention to form a negative electrode for a non-aqueous electrolyte secondary battery, other materials constituting the battery such as a positive electrode material, a separator, and an electrolyte are not particularly limited, and conventional non-aqueous solvent secondary batteries can be used Materials used or various materials currently proposed.

For example, as a cathode material, a layered oxide system (represented by LiMO ₂ or NaMO ₂ , M is a metal: for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , NaFeO ₂ , NaNiO ₂ , NaCoO ₂ , NaMnO ₂ , NaVO ₂ , LiNi _x Co _y Mo _z O ₂ or NaNi _x Mn _z O ₂ (where x, y, z represent composition ratio)), olivine series (represented by LiMPO ₄ or NaMPO ₄ , M is a metal: for example, LiFePO ₄ or NaFePO _4, etc.), a spinel series (represented by LiM ₂ O ₄ or NaM ₂ O ₄ , M is a metal: for example, LiMn ₂ O ₄ or NaMn ₂ O _4, etc.), a compound metal chalcogen element compound, more preferably It is also possible to mix and use these oxygen group element compounds as required. These positive electrode materials are molded together with a suitable binder and a carbon material for imparting conductivity to the electrode to form a layer on the conductive current collector, thereby forming a positive electrode.

The non-aqueous solvent-based electrolyte used in combination of these positive and negative electrodes is generally formed by dissolving an electrolyte in a non-aqueous solvent. As the non-aqueous solvent, for example, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dimethoxyethane, diethoxyethane, γ-butyrolactone, tetrahydrofuran can be used alone. , Organic solvents such as 2-methyltetrahydrofuran, cyclobutane, or 1,3-dioxolane (1,3-dioxolane), or a combination of two or more of these. In addition, as an electrolyte, in lithium ion secondary battery applications, LiClO ₄ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiAsF ₆ , LiCl, LiBr, LiB(C ₆ H ₅ ) ₄ or LiN(SO ₃ CF ₃ ) ₂ etc.; in sodium ion secondary battery applications, NaClO ₄ , NaPF ₆ , NaBF ₄ , NaCF ₃ SO ₃ , NaAsF ₆ , NaCl, NaBr, NaB(C ₆ H ₅ ) ₄ or NaN(SO ₃ CF ₃ ) ₂ and so on.

The non-aqueous electrolyte secondary battery is generally formed by immersing the positive electrode and the negative electrode formed as described above in an electrolyte solution through a liquid-permeable separator facing each other as required. As such a separator, a penetrable or liquid-permeable separator made of nonwoven fabric and other porous materials generally used in secondary batteries can be used. Alternatively, a solid electrolyte containing a polymer glue obtained by impregnating an electrolyte solution may be used instead of the separator or together with the separator.

The carbonaceous material of the present invention is suitable as a carbonaceous material for batteries (typically, non-aqueous electrolyte secondary batteries for driving vehicles) mounted on vehicles such as automobiles. In the present invention, the vehicle is generally known as an electric vehicle, or a hybrid vehicle with a fuel cell or an internal combustion engine, etc., and the subject is not particularly limited, but at least a power supply device having the above-mentioned battery is provided, and the power source The electric drive mechanism driven by the power supply of the device and the control device that controls them. The vehicle may further include electric braking and regenerative braking, and a mechanism that converts energy from braking into electric power and charges the non-aqueous electrolyte secondary battery.

Since the carbonaceous material of the present invention preferably has low electrical resistance, for example, it can also be used as an additive for imparting conductivity to the electrode material of a battery. The type of battery is not particularly limited, but non-aqueous electrolyte secondary batteries and lead storage batteries are preferred. By adding to the electrode material of such a battery, a conductive network can be formed, and irreversible reactions can be suppressed by improving the conductivity, so the battery life can also be extended. [Example]

Hereinafter, the present invention will be described in detail based on the embodiments, but these contents do not limit the scope of the present invention. In addition, although the measurement method of the physical property value of a carbonaceous material is described below, the physical property value described in this specification including an Example is based on the value calculated|required by the following method.

(Elemental analysis) The oxygen, nitrogen, and hydrogen analyzer EMGA-930 manufactured by Horiba Manufacturing Co., Ltd. was used to perform elemental analysis based on the inert gas dissolution method. The detection method of the device is oxygen: inert gas melting-non-dispersive infrared absorption method (NDIR), nitrogen: inert gas melting-thermal conduction method (TCD), hydrogen: inert gas melting-non-dispersive infrared absorption method ( NDIR); calibration is performed using (oxygen･nitrogen) Ni capsules, TiH ₂ (H standard sample), SS-3 (N, O standard sample), and the previous treatment is to measure the water content at 250°C for about 10 minutes After that, 20 mg of the sample was taken into the Ni capsule, and the measurement was performed after degassing in the elemental analyzer for 30 seconds. The test system analyzes 3 samples, and uses the average value as the analysis value. As described above, the nitrogen atom content, oxygen atom content, and hydrogen atom content in the sample are obtained.

(Raman spectroscopy) Using a Raman spectrometer (LabRAM ARAMIS (VIS) manufactured by Horiba Manufacturing Co., Ltd.), the measurement target particles (carbonaceous material or carbide) are set on the observation platform stage, and the objective lens magnification is 100 times. Align the focus and measure while irradiating the argon ion laser. Detailed measuring conditions are as follows, the half-peak of 1360cm ^-1 of Raman spectra near the calculated value of the width of the value obtained, the peak intensity of 1360cm ^-1 of Raman spectrum near (I ₁₃₆₀₎ and the peak intensity near 1580cm ^-1 ( I ₁₅₈₀ ) intensity ratio (R value, I ₁₃₆₀ /I ₁₅₈₀ ). The wavelength of the argon ion laser light: 532nm The laser power on the sample: 15mW Optical resolution: 5～7cm ^-1 Measuring range: 50～2000cm ^-1 Exposure time: 1 second Cumulative times: 100 times Peak intensity measurement: baseline correction Polynom-3 times automatic correction peak search & fitting processing GaussLoren

(Specific surface area obtained by nitrogen adsorption BET method) The approximate formula derived from the BET formula is described below.

Using the above approximation formula, substituting the multi-point method at the temperature of liquid nitrogen by nitrogen adsorption and the actually measured adsorption amount (v) at a given relative pressure (p/p ₀ ) to obtain v _m , by The specific surface area (SSA: unit of m ² g ^-1 ) of the sample is calculated by the following formula.

In the above formula, v _m is the amount of adsorption (cm ³ /g) required to form a monolayer on the sample surface, v is the measured adsorption amount (cm ³ /g), p ₀ is the saturated vapor pressure, and p is the absolute pressure , C is a constant (reflecting the heat of adsorption), N is the Avogajue constant 6.022×10 ²³ , and a (nm ² ) is the area occupied by adsorbate molecules on the sample surface (cross-sectional area occupied by molecules).

Specifically, using "Autosorb-iQ-MP" manufactured by Quantachrome, as described below, the amount of nitrogen adsorbed on the carbonaceous material at the temperature of liquid nitrogen was measured. The measurement sample is filled into the sample tube, and the sample tube is cooled to -196° C., temporarily reduced pressure, and then nitrogen (purity 99.999%) is adsorbed to the measurement sample at the expected relative pressure. The amount of nitrogen adsorbed on the sample when the equilibrium pressure is reached at each expected relative pressure is taken as the amount of adsorbed gas v.

(True density obtained by the butanol method) The true density ρ _Bt is measured by the butanol method in accordance with the method established by JIS R 7212. Accurately measure the mass (m ₁ ) of a pycnometer with a side tube with an internal volume of about 40 mL. Next, the sample was placed flat at the bottom to have a thickness of about 10 mm, and then the mass (m ₂ ) was accurately measured. Add 1-butanol smoothly to a depth of about 20 mm from the bottom. Then, a slight vibration was applied to the pycnometer, and after confirming that no large bubbles were generated, it was placed in a vacuum dryer and slowly evacuated to 2.0 to 2.7 kPa. Keep the pressure at this pressure for more than 20 minutes. After the generation of bubbles stops, take out the pycnometer, fill it with 1-butanol, close the lid and immerse it in a constant temperature water tank (adjusted to 30±0.03°C) for more than 15 minutes. The liquid level of 1-butanol is consistent with the marking line. Then, take it out and carefully wipe the outside, after cooling to room temperature, the mass (m ₄ ) is accurately measured. Next, the same pycnometer was filled with 1-butanol, and it was immersed in a constant temperature water tank in the same manner as described above, and the mass (m ₃ ) was measured after it was in line with the marked line. In addition, the pycnometer is placed in distilled water that will be boiled to remove the dissolved gas before use, and then immersed in a constant temperature water tank in the same manner as above, and the mass (m ₅ ) is measured after it is consistent with the marked line. The true density ρ _Bt is calculated by the following formula. At this time, d is the specific gravity of water at 30°C (0.9946).

(True density obtained by the helium method) The true density ρ _He is measured by the helium method in accordance with the method established by JIS Z 8807. Specifically, the measurement is performed as follows. The measuring container with an internal volume of approximately 4.5 cm ³ is washed and sufficiently dried. As a measuring device, a device that connects a sample chamber with a gas supply valve and an expansion chamber with an exhaust valve through a connection valve is used. Close the gas supply valve of the sample chamber, and put the measuring container into the sample chamber. Open the gas supply valve and the connecting valve to allow helium to flow into the sample chamber for 1 minute, thereby replacing the sample chamber and the expansion chamber with helium. Then close the exhaust valve and the connecting valve, pressurize the sample chamber to 18 psi, close the gas supply valve, and measure the pressure in the sample chamber (p _1C ) with a pressure gauge. Open the connecting valve and measure the pressure (p _2C ) of the sample chamber and the expansion chamber with a pressure gauge. Then put the volume standard substance in the measuring container, repeat the same operation as above, measure the pressure when the gas is introduced (p _1S ) and the pressure when the connecting valve is opened to expand the gas (p _2S ). Open the exhaust valve and take out the measuring container and volume standard substance. Then, after measuring the weight of the measuring sample, put it into the measuring container. Repeat the same operation as above to measure the pressure (p ₁ ) when the gas is introduced and the pressure (p ₂ ) when the connecting valve is opened to expand the gas. The true density ρ is calculated from the above measurement result in accordance with the formula described in JIS Z 8807.

(Silicon content) The measurement method of silicon content is, for example, measured by the following method. Prepare a carbon sample containing a predetermined silicon element in advance, and use a fluorescent X-ray analyzer to make a calibration curve related to the relationship between the intensity of the silicon Kα line and the silicon content. Next, the intensity of the silicon Kα line in the fluorescent X-ray analysis is measured for the sample, and the silicon content is obtained from the calibration curve previously created. Fluorescence X-ray analysis was performed under the following conditions using "ZSX Primus-μ" manufactured by Rigaku Co., Ltd. Using the carrier for the upper irradiation method, the sample measurement area is within a circle with a diameter of 30 mm. In a mortar, 2.0 g of the sample to be measured and 2.0 g of a polymer binder (Spectro Blend 44μ Powder manufactured by Chemplex) were mixed and placed in a molding machine. A load of 15 ton was applied to the molding machine for 1 minute to produce pellets with a diameter of 40 mm. The pellets made by covering with polypropylene film are set on a sample carrier for measurement. The X light source is set to 40kV and 75mA for measurement.

(Average particle size D ₅₀ obtained by the laser scattering method) The average particle size (particle size distribution) of the carbonaceous material or carbide is measured by the following method. The sample was put into an aqueous solution containing 5 mass% of a surfactant ("Toriton X100" manufactured by Wako Pure Chemical Industries, Ltd.), treated with an ultrasonic cleaner for 10 minutes or more, and dispersed in the aqueous solution. The particle size distribution was measured using this dispersion. The particle size distribution measurement was performed using a particle size and particle size distribution measuring device ("MicrotracMT3300EXII" manufactured by MicrotracBel Co., Ltd.). D ₅₀ is the particle size at which the cumulative volume becomes 50%, and this value is used as the average particle size.

(X-ray diffraction) The sample carrier is filled with carbonaceous material or carbide powder, and X-ray diffraction measurement is performed using MiniFlex II manufactured by Rigaku Corporation. Take CuKα(λ=1.5418Å) as the ray source, and the scanning range is 10°＜2θ＜35°

(Circularity) The circularity of the carbonaceous material is measured by the following method. The sample was put into an aqueous solution containing 5 mass% of a surfactant ("Toriton X100" manufactured by Wako Pure Chemical Industries, Ltd.), and dispersed in the aqueous solution. Using this dispersion liquid, shape particle size distribution measurement was performed using a shape particle size distribution measuring device FPIA-3000 manufactured by Sysmex Co., Ltd. to calculate the degree of circularity.

(Electrode density) The electrode density is calculated by measuring the weight of the electrode produced by the electrode production method described later, and dividing the weight by the electrode volume calculated from the product of the electrode area and the electrode thickness.

(Production Example 1) In an air environment, 20 g of starch was heated to 220°C. At this time, the rate of temperature increase up to 220°C was 300°C/hour (5°C/min). Next, the carbon precursor was obtained by performing a heat treatment at 220°C for 3 hours under a stream of air. At this time, the amount of air supplied is 35 L/min per 100 g of starch, and 0.25 L/(min･m ² ) per unit surface area of starch. In addition, Manufacturing Example 1 corresponds to the above-mentioned step (1).

(Manufacturing example 2) After dissolving 0.4 g of p-toluenesulfonic acid (PTSA) in 20 mL of acetone, 20 g of starch was added, and the mixture was stirred for 30 minutes using a magnetic stirrer. A rotary evaporator was used to distill acetone from the obtained mixture, thereby obtaining a mixture of PTSA and starch. In addition, Manufacturing Example 2 corresponds to the above-mentioned step (4).

(Example 1) In a nitrogen atmosphere, the carbon precursor obtained in Production Example 1 was heated to the first temperature of 600°C. At this time, the rate of temperature increase up to 600°C is 600°C/hour (10°C/min). Next, heat treatment is performed at a low-temperature sintering temperature of 600° C. for 60 minutes under nitrogen gas flow, thereby performing carbonization treatment to obtain carbides. At this time, the supply amount of nitrogen gas is 1 L/min per 10 g of carbon precursor, and 0.047 L/(min･m ² ) per unit surface area of the carbon precursor. Next, the obtained carbide is pulverized with a ball mill, thereby obtaining pulverized carbide. The crushed carbide is then heated to a second temperature of 1200°C. At this time, the rate of temperature increase up to 1200°C is 600°C/hour (10°C/min). Next, heat treatment is performed at a high-temperature sintering temperature of 1200°C for 60 minutes, thereby performing high-temperature sintering treatment to obtain a carbonaceous material. The temperature-raising step of heating to the second temperature and the high-temperature sintering treatment of heat treatment at 1200°C for 60 minutes are performed under a nitrogen gas stream. The amount of nitrogen supplied is 3L/min per 5g of crushed carbide, and 0.033L/(min･m ² ) per unit surface area of crushed carbide.

(Example 2) In a nitrogen atmosphere, the carbon precursor obtained in Production Example 1 was heated to the first temperature of 800°C. At this time, the rate of temperature increase up to 800°C is 800°C/hour (10°C/min). Next, under a nitrogen stream, heat treatment is performed at a low-temperature sintering temperature of 800° C. for 60 minutes to perform carbonization treatment to obtain carbides. Here, the amount of nitrogen supplied is 1 L/min per 10 g of the carbon precursor, and 0.047 L/(min･m ² ) per unit surface area of the carbon precursor. The subsequent pulverization and high-temperature sintering treatment were performed in the same manner as in Example 1 to obtain a carbonaceous material.

(Example 3) A carbonaceous material was obtained in the same manner as in Example 1, except that the mixture obtained in Production Example 2 was used instead of the carbon precursor obtained in Production Example 1.

(Comparative example 1) A carbonaceous material was obtained in the same manner as in Example 1, except that glucose was used instead of the carbon precursor obtained in Production Example 1, and the first temperature and the low-temperature sintering temperature were set to 1000°C.

(Comparative Example 2) Glucose and ammonium chloride were mixed in a mortar. In a nitrogen atmosphere, the resulting mixture was heated to 1000°C. At this time, the rate of temperature increase up to 1000°C was 240°C/hour (4°C/min). Next, heat treatment is performed at 1000° C. for 60 minutes under a nitrogen gas stream to perform carbonization treatment to obtain carbides (low-temperature sintering). The amount of nitrogen supplied at this time is 10 L/min per 5 g of glucose. After that, the obtained carbide is pulverized with a ball mill to obtain pulverized carbide. Next, the pulverized carbide is heated to 1300°C, and a heat treatment is performed at 1300°C for 60 minutes to perform high-temperature sintering treatment to obtain a carbonaceous material (high-temperature sintering). At this time, the rate of temperature increase up to 1300°C is 600°C/hour (10°C/min). The above-mentioned heating and heat treatment are carried out under nitrogen gas flow. The amount of nitrogen supplied is 3L/min per 5g of crushed carbide, and 0.075L/(min･m ² ) per unit surface area of crushed carbide.

(Comparative example 3) In a nitrogen environment, the coconut husk as a raw material was heated to 600°C. At this time, the rate of temperature increase up to 600°C is 600°C/hour (10°C/min). Next, heat treatment is performed at 600° C. for 60 minutes under a nitrogen stream, thereby performing carbonization treatment to obtain carbides. At this time, the supply amount of nitrogen gas was 1 L/min per 20 g of raw materials. After that, the obtained carbide is pulverized with a ball mill to obtain pulverized carbide. Next, the pulverized carbide was heated to 900°C, and heat-treated at 900°C for 60 minutes to obtain the heat-treated pulverized carbide. The above temperature rise is performed under nitrogen gas flow, and the heat treatment is performed under 2vol%/98vol% hydrogen chloride/nitrogen mixed gas flow. The supply amount of the mixed gas is 10L/min per 10g of crushed carbide. Furthermore, the obtained heat-treated pulverized carbide was heated to 1200°C, and heat-treated at 1200°C for 60 minutes to perform high-temperature sintering treatment to obtain a carbonaceous material. At this time, the rate of temperature increase up to 1200°C is 600°C/hour (10°C/min). The above-mentioned heating and heat treatment are carried out under nitrogen gas flow. The amount of nitrogen supplied is 3L/min per 5g of crushed carbide by heat treatment.

(Example 4) In a nitrogen atmosphere, 40 g of cellulose (D ₅₀ =10 μm, no melting point) was heated to the first temperature of 600°C. At this time, the rate of temperature increase up to 600°C is 600°C/hour (10°C/min). Next, under a nitrogen stream, heat treatment is performed at a low-temperature sintering temperature of 600° C. for 60 minutes to perform carbonization treatment to obtain carbides. At this time, the supply amount of nitrogen is 1 L/min per 10 g of cellulose, and 0.098 L/(min･m ² ) per unit surface area of cellulose. The recovered carbide was 6.94g, and the recovery rate relative to cellulose was 17.4%. The resulting carbide maintains the raw material shape and D _{50 of} cellulose, so the crushing and classification steps are omitted. Next, 3 g of the obtained carbide was heated to a second temperature of 1200°C. At this time, the rate of temperature increase up to 1200°C is 600°C/hour (10°C/min). Next, heat treatment is performed at a high-temperature sintering temperature of 1200°C for 60 minutes, thereby performing high-temperature sintering treatment to obtain a carbonaceous material. The temperature-raising step of heating to the second temperature and the high-temperature sintering treatment of heat treatment at 1200°C for 60 minutes were performed under a nitrogen gas stream. The amount of nitrogen supplied is 1L/min per 1g of carbide, and 0.328L/(min･m ² ) per unit surface area of carbide. The recovered carbonaceous material is 2.68g, the recovery rate relative to carbide is 89.1%, and the recovery rate relative to cellulose is 15.5%.

(Example 5) In a nitrogen atmosphere, cellulose (D ₅₀ =10 μm, no melting point) was heated to the first temperature of 800°C. At this time, the rate of temperature increase up to 800°C is 600°C/hour (10°C/min). Next, under a nitrogen stream, heat treatment is performed at a low-temperature sintering temperature of 800° C. for 60 minutes to perform carbonization treatment to obtain carbides. Here, the amount of nitrogen supplied is 1 L/min per 10 g of the carbon precursor, and 0.047 L/(min･m ² ) per unit surface area of the carbon precursor. The subsequent high-temperature sintering treatment was performed in the same manner as in Example 4 to obtain a carbonaceous material.

(Comparative Example 4) In a nitrogen atmosphere, 40 g of glucose (D ₅₀ =15 μm, melting point = 156°C) as a raw material was heated to the first temperature of 1000°C. At this time, the rate of temperature increase up to 1000°C is 600°C/hour (10°C/min). Next, heat treatment is performed at a low-temperature sintering temperature of 1000° C. for 60 minutes under a nitrogen gas stream, thereby performing carbonization treatment to obtain carbides. At this time, the supply amount of nitrogen gas is 1 L/min per 10 g of glucose, and 0.049 L/(min･m ² ) per unit surface area of glucose. The recovered carbide was 7.68 g, which was 19.2% relative to glucose. The resulting carbides were welded and foamed, and the raw material shape of glucose was not maintained. Therefore, they were crushed by a ball mill and classified by a jet mill. A recovery rate of 65.4% was used to obtain crushed carbides with D ₅₀ =10 μm. Next, 3 g of the obtained crushed carbide was heated to a second temperature of 1300°C. At this time, the rate of temperature increase up to 1300°C is 600°C/hour (10°C/min). Next, heat treatment is performed at a high-temperature sintering temperature of 1300°C for 60 minutes, thereby performing high-temperature sintering treatment to obtain a carbonaceous material. The temperature-raising step of heating to the second temperature and the high-temperature sintering treatment of heat treatment at 1300°C for 60 minutes were performed under a nitrogen gas stream. The amount of nitrogen supplied is 1L/min per 1g of crushed carbide, and 0.328L/(min･m ² ) per unit surface area of carbide. The recovered carbonaceous material was 2.83 g, the recovery rate to carbide was 94.3%, and the recovery rate to glucose was 11.8%.

(Comparative Example 5) In a nitrogen atmosphere, 100 g of coconut shell (particle size 4-6 mm, no melting point) as a raw material was heated to 600°C. At this time, the rate of temperature increase up to 600°C is 600°C/hour (10°C/min). Next, heat treatment is performed at 600° C. for 60 minutes under a nitrogen gas stream to perform carbonization treatment to obtain carbides. At this time, the supply amount of nitrogen is 1 L/min per 20 g of raw materials. The recovered carbide was 25.4 g, and the recovery rate relative to the coconut shell was 25.4%. The obtained carbide maintains the raw material shape and particle size of the coconut shell, but it is not the particle size suitable for making the negative electrode. Therefore, it is pulverized by a ball mill and classified by a jet mill to obtain a pulverized carbide with D ₅₀ =10 μm at a recovery rate of 60.0%. Next, 25 g of the pulverized carbide was heated to 900°C, and heat-treated at 900°C for 60 minutes to obtain a heat-treated pulverized carbide. The above temperature rise is performed under nitrogen gas flow, and the heat treatment is performed under 2vol%/98vol% hydrogen chloride/nitrogen mixed gas flow. The supply amount of the mixed gas is 10L/min per 10g of crushed carbide. Furthermore, the obtained heat-treated pulverized carbide was heated to 1200°C, and heat-treated at 1200°C for 60 minutes, thereby performing high-temperature sintering treatment to obtain a carbonaceous material. At this time, the rate of temperature increase up to 1200°C is 600°C/hour (10°C/min). The above-mentioned heating and heat treatment are carried out under nitrogen gas flow. The amount of nitrogen supplied is 3L/min per 5g of crushed carbide by heat treatment. The recovered carbonaceous material was 20.1 g, the recovery rate relative to the crushed carbide was 80.5%, and the recovery rate relative to the coconut shell was 12.3%.

(Production of electrodes) Using the carbonaceous materials obtained in the respective examples and the respective comparative examples, the negative electrode was produced by the following procedure. Mix 95 parts by mass of carbonaceous material, 2 parts by mass of conductive carbon black ("Super-P (registered trademark)" manufactured by TIMCAL), 1 part by mass of CMC, 2 parts by mass of SBR, and 90 parts by mass of water, Obtain a slurry. The obtained slurry was applied to a copper foil with a thickness of 18 μm, dried and then pressed to obtain an electrode with a thickness of 45 μm. The density of the obtained electrode is shown in Table 3 and Table 5.

(impedance) Using the electrode produced above, using an electrochemical measuring device ("1255WB high-performance electrochemical measuring system" manufactured by Solartron), at 25°C, with an amplitude of 10mV centered on 0V, and measuring at a frequency of 10mHz to 1MHz. Voltage AC impedance, and measure the real part resistance at a frequency of 1kHz as the impedance resistance. The results obtained are shown in Table 3 and Table 5 as the impedance at the initial charge and discharge.

(DC resistance value, initial battery capacity and charge-discharge efficiency) The electrode produced above was used as a working electrode, and metallic lithium was used as a counter electrode and a reference electrode. As a solvent, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate are mixed and used so that the volume ratio becomes 1:1:1. Dissolve 1 mol/L LiPF ₆ in this solvent to use it as an electrolyte. A polypropylene film is used for the separator. Make coin-type batteries in a glove box in an argon environment. For the lithium secondary battery with the above configuration, a charge and discharge test device (manufactured by Toyo Systems Co., Ltd., "TOSCAT") was used to measure the DC resistance value before initial charging, and then perform a charge and discharge test. The doping of lithium was performed at a rate of 70 mA/g with respect to the mass of the active material, and the doping was performed until the potential with respect to the lithium became 1 mV. Furthermore, a constant voltage of 1 mV was applied to the lithium potential for 8 hours to complete the doping. The capacity (mAh/g) at this time was taken as the charging capacity. Next, dedoping was performed at a rate of 70 mA/g with respect to the mass of the active material until the potential with respect to lithium became 2.5 V, and the discharged capacity at this time was regarded as the discharge capacity. The percentage of discharge capacity/charge capacity was used as the charge and discharge efficiency (initial charge and discharge efficiency), and was used as an index of the utilization efficiency of lithium ions in the battery. The results obtained are shown in Table 3 and Table 5 as the DC resistance, discharge capacity, irreversible capacity, and charge and discharge efficiency during the initial charge and discharge.

The sintering conditions in each example and each comparative example and the result of physical property evaluation of the obtained carbonaceous material are shown in Table 1 and Table 4. Table 2 shows the evaluation results of physical properties of carbides obtained as intermediates during the production of carbonaceous materials. In addition, the evaluation results of the battery characteristics are shown in Table 3 and Table 5.

Batteries made using the carbonaceous materials of each of Examples 1 to 3, on the one hand, maintain a certain charge and discharge efficiency, and on the other hand, exhibit a high discharge capacity. Also, it was confirmed that the resistance value was also low. On the other hand, it is produced using the carbonaceous material of each comparative example of Comparative Examples 1 to 3 that does not have a predetermined nitrogen content or a Raman spectrum with a predetermined range of the half-value width of the peak near 1360 cm ^-1 The battery does not have both high discharge capacity and charge and discharge efficiency.

In the preparation methods of each of Examples 4 to 5, since there is no welding during low-temperature sintering, the pulverization and classification steps can be omitted, confirming that carbonaceous materials can be obtained at a high recovery rate. In addition, batteries made using the carbonaceous materials of each of Examples 4 to 5 have been confirmed to maintain a certain charge and discharge efficiency while exhibiting a high discharge capacity and a low resistance value. On the other hand, the carbonaceous material obtained by the method of Comparative Example 1 using monosaccharides with melting point as the raw material has low electrical resistance, but low discharge capacity, and must include pulverization and classification due to shape changes during low-temperature sintering Steps, resulting in low recovery rates. In addition, the carbonaceous material obtained by the production method of Comparative Example 3 using coconut shell with a large particle size as the raw material has low discharge capacity and resistance value. Although the shape does not change during low-temperature sintering, the particle size is not suitable for making a negative electrode. Including crushing and classification steps, resulting in low recovery rate.

[Table 1] Carbonaceous material Sintering conditions Low temperature sintering temperature High temperature sintering temperature Nitrogen atom content Half width R value Specific surface area True density Silicon content Average particle size D ₅₀ Carbon surface interval d ₀₀₂ Circularity ρ _Bt ρ _He [℃] [℃] [quality%] [cm ^-1 ] [m ² /g] [g/cm ³ ] [g/cm ³ ] [ppm] [μm] [Å] Example 1 600 1200 0.69 202 1.19 22.0 1.51 2.02 78 10.1 3.84 9.80 2 800 1200 0.78 210 1.18 20.8 1.53 2.04 75 9.8 3.88 9.80 3 600 1200 0.91 196 1.19 25.6 1.45 2.05 76 16.9 3.81 9.81 Comparative example 1 1000 1200 0.12 166 1.18 54.1 1.48 1.98 75 13.0 3.81 9.54 2 1000 1300 0.78 171 1.18 28.4 1.53 2.00 74 8.2 3.79 9.70 3 600 → 900 1200 0.27 174 1.22 54.0 1.47 2.12 327 7.0 3.79 9.73

[Table 2] carbide Nitrogen atom content Oxygen atom content Hydrogen atom content Half width R value Specific surface area True density ρ _He Average particle size D ₅₀ Carbon surface interval d ₀₀₂ [quality%] [quality%] [quality%] [cm ^-1 ] [m ² /g] [g/cm ³ ] [μm] [Å] Example 1 0.45 5.48 2.51 286 0.69 480 1.50 11.0 3.94 2 0.52 3.10 2.15 269 0.91 376 1.52 10.5 3.88 3 0.59 4.43 2.47 278 0.69 452 1.49 18.1 3.78

[table 3] Discharge capacity Irreversible capacity Charge and discharge efficiency DC resistance during initial charge and discharge Impedance during initial charge and discharge Electrode density [mAh/g] [mAh/g] [%] [Ω] [Ω] [g/cc] Example 1 450 91 83.2 849 10.5 1.007 2 456 85 84.3 814 9.9 1.014 3 445 89 83.3 851 12.1 0.943 Comparative example 1 362 73 83.2 595 9.7 0.949 2 430 105 80.4 1100 22.3 0.976 3 371 82 81.8 1265 26 0.945

[Table 4] Carbonaceous material Sintering conditions Low temperature sintering temperature High temperature sintering temperature Low temperature sintering recovery rate Crushing classification recovery rate High temperature sintering recovery rate Total recovery Nitrogen atom content Half width R value Specific surface area True density Silicon content Average particle size D ₅₀ Carbon surface interval d ₀₀₂ Circularity ρ _Bt ρ _He [℃] [℃] [%] [%] [%] [%] [quality%] [cm ^-1 ] [m ² /g] [g/cm ³ ] [g/cm ³ ] [ppm] [μm] [Å] Example 4 600 1200 17.4 - 89.1 15.5 0.55 198 1.20 9.7 1.49 2.02 154 10 3.87 8.67 5 800 1200 15.6 - 90.5 14.1 0.78 210 1.18 13.8 1.48 1.99 178 10 3.89 8.67 Comparative example 4 1000 1300 19.2 65.4 94.3 11.8 0.12 166 1.18 54.1 1.48 1.98 75 10 3.81 9.54 5 600 900→ 1200 25.4 60.0 80.5 12.3 0.27 174 1.22 54.0 1.47 2.12 327 7.0 3.79 9.73

[table 5] Discharge capacity Irreversible capacity Charge and discharge efficiency DC resistance during initial charge and discharge Impedance during initial charge and discharge Electrode density [mAh/g] [mAh/g] [%] [Ω] [Ω] [g/cc] Example 4 403 106 79.1 1208 9.3 0.900 5 410 101 80.2 1150 8.7 0.921 Comparative example 4 351 73 82.8 657 9.8 0.906 5 371 82 81.8 1265 26 0.945

no.

no.

no.

Claims (18)

A carbonaceous material in which the nitrogen atom content obtained by elemental analysis is above 0.4% by mass and less than 1.0% by mass, and the half-value width of the peak near 1360cm ^-1 of the Raman spectrum observed by laser Raman spectroscopy The value is 180～220cm ^-1 . Such as the carbonaceous material of claim 1, wherein the specific surface area obtained by the BET method is less than 100 m ² /g. Such as the carbonaceous material of claim 1 or 2, in which the true density obtained by the BuOH method is above 1.45. Such as the carbonaceous material of any one of claims 1 to 3, wherein the content of silicon element is less than 200 ppm. For example, the carbonaceous material of any one of claims 1 to 4 has an average particle size D ₅₀ of 30 μm or less. Such as the carbonaceous material of any one of claims 1 to 5, wherein the carbon surface interval d ₀₀₂ calculated using the Bragg formula obtained by the wide-angle X-ray diffraction method is 3.75Å or more. Such as the carbonaceous material of any one of claims 1 to 6, which is derived from a substance having a carbohydrate skeleton. Such as the carbonaceous material of claim 7, wherein the substance with a carbohydrate skeleton is a polysaccharide without a melting point. A negative electrode for a non-aqueous electrolyte secondary battery, comprising the carbonaceous material according to any one of claims 1 to 8. A non-aqueous electrolyte secondary battery having the negative electrode for a non-aqueous electrolyte secondary battery as in Claim 9. A method for manufacturing a carbonaceous material according to any one of claims 1 to 8, which at least includes the following steps: (1) Under the supply of oxygen-containing gas, the carbon precursor is processed at a temperature ranging from 215 to 240°C. The step of heat-treating the raw materials for 1-12 hours to obtain a carbon precursor; (2A) In an inert gas environment, heating the carbon precursor to the range of 500-900°C at a temperature rising rate of 100°C/hour or more The first temperature step; (2B) A step of heat-treating the carbon precursor at a temperature of 500 to 900°C under the supply of inert gas to obtain carbide; here, the supply amount of inert gas is The surface area of the carbon precursor is 0.01～5.0L/(minute･m ² ) per unit; (3A) In an inert gas environment, the carbide is heated to 1000～1000 at a temperature rising rate of 100℃/hour or more The second temperature step in the range of 1400°C; and (3B) the step of heat-treating the carbide at a temperature of 1000 to 1400°C under the supply of an inert gas to obtain a carbonaceous material; here, the inert gas The supply amount of is 0.01～5.0L/(minute･m ² ) per unit surface area of carbide. A method for manufacturing a carbonaceous material according to any one of claims 1 to 8, which comprises at least the following steps: (4) Combining a raw material of a carbon precursor with 1-20 parts by mass relative to 100 parts by mass of the raw material A step of mixing at least one organic acid to obtain a mixture; (5A) A step of heating the mixture to the first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment (5B) The step of heat-treating the mixture at a temperature of 500 to 900°C under the supply of inert gas to obtain carbides; here, the supply of inert gas is based on each of the raw materials contained in the mixture 0.01～5.0L/(minute･m ² ) per unit surface area; (6A) In an inert gas environment, the carbide is heated to the range of 1000～1400℃ at a heating rate of 100℃/hour or more The step of the second temperature; and (6B) the step of heat-treating the carbide at a temperature of 1000 to 1400°C under the supply of inert gas to obtain a carbonaceous material; here, the amount of inert gas supplied is It is 0.01～5.0L/(minute･m ² ) per unit surface area of carbide. A method for manufacturing a carbonaceous material according to any one of claims 1 to 8, which at least comprises the following steps: (12A) In an inert gas environment, at a temperature rising rate of 100°C/hour or more, the polysaccharide The step of heating to the first temperature in the range of 500-900°C; (12B) The step of heat-treating the polysaccharide at a temperature of 500-900°C under the supply of inert gas to obtain carbides; here, The supply amount of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of polysaccharides; (13A) In an inert gas environment, at a heating rate above 100°C/hour , The step of heating the carbide to a second temperature in the range of 1000 to 1600°C; and (13B) under the supply of inert gas, heat treating the carbide at a temperature of 1000 to 1600°C to obtain a carbonaceous material Here, the supply of inert gas is 0.01～5.0L/(minute･m ² ) per unit surface area of carbide. The manufacturing method of claim 13, wherein the polysaccharide is cellulose or an analog thereof. The manufacturing method of claim 13, wherein the polysaccharide contains a cross-linked structure. A carbide whose nitrogen atom content obtained by elemental analysis is above 0.20% by mass and below 0.90% by mass, and the value of the half-value width of the peak near 1360cm ^-1 of the Raman spectrum observed by laser Raman spectroscopy It is 250cm ^-1 to 300cm ^-1 or less. A method for manufacturing a carbide according to claim 16, which at least comprises: (1) Under the supply of oxygen-containing gas, heat treatment of the raw material of the carbon precursor at a temperature range of 215 to 240°C for 1 to 12 hours, and The step of obtaining a carbon precursor; (2A) a step of heating the carbon precursor to a first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment; and (2B) ) Under the supply of inert gas, the step of heat-treating the carbon precursor at a temperature of 500 to 900°C to obtain carbide; here, the supply of inert gas is based on each unit surface area of the carbon precursor The medium is 0.01～5.0L/(minute･m ² ). A method for manufacturing a carbide according to claim 16, which comprises at least: (4) mixing a raw material of a carbon precursor with 1-20 parts by mass of at least one organic acid relative to 100 parts by mass of the raw material to obtain The step of mixing the mixture; (5A) the step of heating the mixture to the first temperature in the range of 500 to 900°C at a temperature increase rate of 100°C/hour or more in an inert gas environment; and (5B) in the inert gas The step of heat-treating the mixture at a temperature of 500-900℃ to obtain carbides under the supply of the mixture; here, the supply amount of the inert gas is 0.01-5.0 per unit surface area of the raw materials contained in the mixture L/(minute･m ² ).