Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
  • C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes
  • C08G8/08—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ
  • C08G8/10—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ with phenol
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
  • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/362—Composites
  • H01M4/366—Composites as layered products
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
  • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/624—Electric conductive fillers
  • H01M4/625—Carbon or graphite
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
  • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
  • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/10—Solid density
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/12—Surface area
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/021—Physical characteristics, e.g. porosity, surface area
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/027—Negative electrodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to a method for producing a carbonaceous material for a negative electrode of a non-aqueous electrolyte secondary battery, a method for producing a non-aqueous electrolyte secondary battery electrode, and a method for producing a non-aqueous electrolyte secondary battery.
• a non-aqueous electrolyte secondary battery electrode capable of obtaining a carbonaceous material having a large dedoping capacity without adding a sodium compound to the carbon precursor by using the phenol resin addition-condensed using the above as the carbon precursor.
• the present invention relates to a method for producing a non-aqueous electrolyte secondary battery and a method for producing a non-aqueous electrolyte secondary battery.
• Patent Document 1 a non-aqueous electrolyte lithium secondary battery using a carbonaceous material as a negative electrode.
• Non-aqueous electrolyte lithium secondary batteries are widely used as high energy density secondary batteries as these power sources, and further high energy density is expected in order to extend the cruising range on a single charge in EV applications. ing.
• All-solid-state batteries are attracting attention as innovative storage batteries for even higher energy densities.
• An all-solid-state battery is a highly safe battery in which a flammable organic electrolyte is replaced with a nonflammable inorganic solid electrolyte.
• a solid electrolyte is used as a conduction path for lithium ions in the electrode layer, high conductivity including contact resistance between particles is required.
• the electrode active material is required not only to have a large dedoping capacity but also to have shape stability (reduction of expansion and contraction) at the time of doping and dedoping when used in an all-solid-state battery.
• Patent Document 2 In order to increase the dedoped capacity of lithium as a negative electrode material, for example, in Patent Document 2, a compound containing an alkali metal element is impregnated with a carbon precursor and then main-fired, or pre-baked and then further main-fired. Then, a method for producing a carbonaceous material used for a negative electrode of a non-aqueous electrolyte secondary battery, which is obtained by coating the obtained calcined charcoal with pyrolytic carbon, has been proposed.
• the carbonaceous material thus obtained is a non-graphitic carbon material having a small expansion and contraction during lithium doping and dedoping, and exhibits a large dedoping capacity as a negative electrode material for a non-aqueous electrolyte secondary battery. Is disclosed.
• the main firing in Patent Document 2 is to fire a carbon precursor impregnated with an alkali metal compound at 800 to 1500 ° C. in a non-oxidizing gas atmosphere. At this time, the compound containing the alkali metal element attached to the carbon precursor is reduced to the alkali metal and evaporated. The alkali metal evaporated in this way precipitates in a low temperature portion below the boiling point (for example, the boiling point of metallic sodium, which is a kind of alkali metal, is 883 ° C, and is a liquid at a temperature below this temperature).
• the carbon precursor reacts with the hydrogen gas generated in the carbonization reaction of the carbon precursor to form an alkali metal hydride compound and precipitates in the low temperature part (for example, sodium hydride decomposes at about 800 ° C. or higher and becomes solid at temperatures below this temperature. be.).
• an alkali metal hydride compound for example, sodium hydride decomposes at about 800 ° C. or higher and becomes solid at temperatures below this temperature. be.
• the doping capacity of the negative electrode is the capacity at which lithium can be doped
• the dedoping capacity is the capacity at which lithium doped in the negative electrode returns to the positive electrode.
• the amount of lithium that can be used repeatedly corresponds to the dedoping capacity. Therefore, the difference between the doping capacity and the dedoping capacity corresponds to the lithium capacity in which lithium in the positive electrode is wasted. Therefore, it is preferable that the difference between the doping capacity and the dedoping capacity is small, and it is not always preferable that only the doping capacity is large. In the basic characteristics of the battery electrode, it is necessary to have a large dedoping capacity.
• the present invention has been made in view of the above circumstances, and manufactures a carbonaceous material for a negative electrode of a non-aqueous electrolyte secondary battery having a large dedoping capacity without adding an alkali metal compound to a carbon precursor.
• the purpose is to provide a method.
• a resole type obtained by addition-condensing a raw material mixture composed of phenols and aldehydes containing 50% by mass or more of phenol with the raw material mixture in the presence of a sodium-based basic catalyst of less than 5% by mass.
• the carbonaceous material obtained by main firing using a phenol resin as a carbon source or by main firing after pre-firing and then coating the obtained calcined charcoal with pyrolytic carbon is excellent in doping / desorption. It has been found that it has a dope capacity, and the present invention has been completed.
• the present invention includes the following embodiments.
• a raw material mixture composed of phenols and aldehydes containing 50% by mass or more of phenol is addition-condensed with respect to the raw material mixture in the presence of a sodium-based basic catalyst of less than 5% by mass.
• Addition condensation step to obtain resole-type phenolic resin (2) The resol type phenol resin is used.
• Pre-calcination at 300 ° C. or higher and lower than 800 ° C. in a non-oxidizing gas atmosphere After that, a firing step of obtaining calcined charcoal by main firing at 950 ° C.
• a method for producing a carbonaceous material for a negative electrode of a non-aqueous electrolyte secondary battery including.
• the coating step is a step of coating the calcined carbon with pyrolytic carbon produced by vapor phase thermal decomposition of an aliphatic hydrocarbon at 600 ° C. or higher and 1500 ° C. or lower.
• the carbonaceous material the true density was measured by butanol method is the 1.20g / cm 3 ⁇ 1.60g / cm 3, specific surface area determined by the BET method by nitrogen adsorption is less than or equal to 30 m 2 / g Any of the above [1] to [4], wherein the average particle size is 50 ⁇ m or less, and the atomic ratio (H / C) of hydrogen atom to carbon atom obtained by elemental analysis is 0.1 or less.
• the non-aqueous electrolyte secondary battery negative electrode carbonaceous material After producing the non-aqueous electrolyte secondary battery negative electrode carbonaceous material by the method for producing the non-aqueous electrolyte secondary battery negative electrode carbonaceous material according to any one of the above [1] to [5], the non-aqueous electrolyte secondary battery negative electrode carbon material is produced.
• a method for manufacturing a non-aqueous electrolyte secondary battery electrode which comprises manufacturing a non-aqueous electrolyte secondary battery electrode using a carbonaceous material for a negative electrode of a water electrolyte secondary battery.
• the non-aqueous electrolyte secondary battery electrode After manufacturing the non-aqueous electrolyte secondary battery electrode by the method for producing the non-aqueous electrolyte secondary battery electrode according to the above [6], the non-aqueous electrolyte secondary battery electrode is used. A method for manufacturing a non-aqueous electrolyte secondary battery.
• a method for producing a carbonaceous material for a negative electrode of a non-aqueous electrolyte secondary battery which can obtain a carbonaceous material having a large dedoping capacity without adding an alkali metal compound to the carbon precursor. be able to.
• Method for producing carbonaceous material for negative electrode of non-aqueous electrolyte secondary battery is as follows: (1) Phenols containing 50% by mass or more of phenol and Add-condensation step of adding and condensing a raw material mixture composed of aldehydes with respect to the raw material mixture in the presence of a sodium-based basic catalyst of less than 5% by mass to obtain a resol-type phenol resin, (2) Resol-type phenol resin. , (A) Main firing at 950 ° C. or higher and 1500 ° C.
• the "carbon precursor” means an organic substance before the main firing. That is, the “carbon precursor” in the production method according to the present invention is a resol type phenol resin. Further, in the present specification, the carbon precursor that has been pre-calcined may be referred to as "pre-calcined charcoal”. Further, the carbonaceous calcined product after the main calcining and before the coating with pyrolytic carbon is sometimes referred to as "firing charcoal".
• phenols containing 50% by mass or more of phenol means that the content of phenol with respect to the total amount of the phenols is 50% by mass or more.
• a resole-type phenol resin obtained by addition-condensing in the presence of less than 5% by mass of a sodium-based basic catalyst with respect to the above-mentioned raw material mixture is used as carbon as a carbonaceous material for a negative electrode of a non-aqueous electrolyte secondary battery. Used as a source.
• the resol-type phenol resin is synthesized in a liquid phase, and sodium in the catalyst is substantially uniformly dispersed inside the resol-type phenol resin.
• the resol type phenol resin When the resol type phenol resin is heat-treated in a non-oxidizing gas atmosphere, carbonization proceeds. At this time, the sodium contained in the resol-type phenol resin is alkali-activated to form voids in the carbonaceous material. The voids thus formed are suitable for storing lithium. Moreover, since sodium is substantially uniformly dispersed in the resole-type phenol resin used here, the carbonaceous material obtained from such a raw material has substantially uniform voids as a whole. As a result, such carbonaceous materials exhibit excellent doping / dedoping capacity.
• the carbonaceous material obtained by using this also has voids formed more uniformly inside as compared with the conventional carbonic material made of an organic substance in which sodium is impregnated with a carbon precursor. Therefore, in the method for producing a carbonaceous material for a negative electrode of a secondary battery, it is possible to suppress the amount of sodium used in order to achieve an excellent doping / dedoping capacity.
• the resol type phenol resin is a resin synthesized by subjecting phenols and aldehydes to an addition condensation reaction in the presence of a basic catalyst.
• a resol-type phenol resin obtained by addition condensation in the presence of a sodium-based basic catalyst in an amount of less than 5% by mass with respect to a raw material mixture composed of phenols and aldehydes is used as a non-aqueous electrolyte. It is used as a carbon source for the carbonaceous material for the negative electrode of the next battery.
• the amount of the sodium-based basic catalyst used in the addition condensation is not particularly limited as long as it is less than 5% by mass. It is preferably less than 4% by mass, more preferably 3.5% by mass or less, further preferably less than 3% by mass, and particularly preferably less than 2% by mass.
• the amount of the sodium-based basic catalyst used is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more. It is particularly preferably 0.7% by mass or more, and most preferably 1% by mass or more.
• phenols are a general term for compounds having a phenolic hydroxyl group on the benzene ring, and specifically, phenol and a phenol derivative in which hydrogen on the benzene ring of phenol is substituted with another substituent.
• phenol derivatives include orthocresol, paracresol, paraphenylphenol, paranonylphenol, 2,3-xylenol, 2,5-xylenol, phenol, metacresol, 3,5-xylenol, resorcinol, bisphenol A, bisphenol F, and bisphenol.
• B bisphenol E, bisphenol H, bisphenol S, catechol, hydroquinone and the like can be mentioned.
• the amount of phenol is not particularly limited as long as it is 50% by mass or more with respect to the total amount of phenols, and is preferably 70% by mass or more, and more preferably 90% by mass or more.
• Aldehydes are a general term for compounds represented by the general formula R-CHO in which hydrogen and an arbitrary functional group (R) are bonded to carbonyl carbon one by one.
• Specific examples of the aldehydes include formaldehyde, acetaldehyde, propionaldehyde, butanal, and multimers of aldehydes such as 1,3,5-trioxane and paraldehyde. It is preferable to use formaldehyde, acetaldehyde and their multimer.
• the total amount of formaldehyde and acetaldehyde is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more, based on the total amount of aldehydes. Further, in one embodiment, the amount of formaldehyde is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more with respect to the total amount of aldehydes.
• the ratio of the amount of phenols to the amount of aldehydes is preferably 0.2 to 3.0 mol of aldehydes with respect to 1 mol of phenols. If the amount of aldehydes is too small, the crosslinked structure may be insufficient and resin formation may be difficult, which is not preferable. On the other hand, if the amount of aldehydes is too large, the dedoping capacity may decrease, which is not preferable.
• the amount of aldehydes with respect to 1 mol of phenols is preferably 0.2 mol or more, more preferably 0.3 mol or more, and particularly preferably 0.4 mol or more.
• the amount of aldehydes with respect to 1 mol of phenols is preferably 3.0 mol or less, more preferably 2.0 mol or less, and particularly preferably 1.5 mol or less.
• the product of the number of mols of the multimer and the number of condensations of the aldehyde is counted as the number of mols of the multimer.
• 1,3,5-trioxane is a trimer of formaldehyde, so it is counted as 3 mol.
• a sodium-based basic catalyst is used as a catalyst in the addition condensation reaction of phenols and aldehydes.
• sodium hydroxide, sodium carbonate and the like can be used as these catalysts. It is preferable to use sodium hydroxide.
• a resol type initial condensate is obtained.
• the obtained initial condensate is obtained as it is (that is, containing the catalyst) and is further dehydrated and cured by applying heat to obtain a resol type phenol resin.
• an acid is added to the solution subjected to the addition condensation reaction to neutralize it, the initial condensate and the solution are separated, and then the initial condensate is heated to dehydrate and harden to obtain a resol type phenol resin.
• the resol-type phenol resin obtained through this addition condensation step has sodium dispersed substantially uniformly inside the resin.
• Patent Document 2 it is not necessary to perform the alkali imposition treatment on the carbon precursor.
• a carbonaceous material exhibiting an excellent doping / dedoping capacity can be obtained without performing an alkali imposition treatment.
• Phenol resin can be crushed if necessary. Thereby, the heat treatment for the preliminary firing and the main firing can be uniformly performed. It can be pulverized before the pre-baking and finely pulverized before the main firing or after the surface treatment.
• the crusher used for crushing is not particularly limited, and for example, a jet mill, a rod mill, a vibrating ball mill, a hammer mill, or the like can be used.
• the average particle size of the phenol resin after crushing is not particularly limited.
• the average particle size is preferably 5 mm or less, more preferably 1 mm or less, and particularly preferably 0.5 mm or less. If the average particle size is too large, the removal of volatile matter becomes non-uniform, which is not preferable.
• the average particle size of the phenol resin was determined according to the method described in JIS K1474: 2014. Specifically, a cumulative particle size diagram is created, and a horizontal line is drawn from the intersection of the vertical line of the point with a horizontal axis (sieving mass percentage%) of 50% and the cumulative particle size diagram, and the horizontal line and the vertical axis are drawn. The numerical value of the mesh opening of the sieve was obtained based on the intersection, and this numerical value was taken as the average particle size.
• the resol type phenol resin is (a) main calcined in a non-oxidizing gas atmosphere at 950 ° C. or higher and 1500 ° C. or lower to obtain calcined charcoal, or (b) non-oxidizing. This is a step of pre-calcining at 300 ° C. or higher and lower than 800 ° C. in a gas atmosphere, and then main firing at 950 ° C. or higher and 1500 ° C. or lower to obtain calcined charcoal.
• pre-baking may be performed at 300 ° C. or higher and lower than 800 ° C. in a non-oxidizing gas atmosphere.
• This pre-calcination is an operation for removing volatile components such as CO 2 , CO, CH 4 , H 2 and the like, which are decomposition products of the phenol resin, and tar components.
• volatile components such as CO 2 , CO, CH 4 , H 2 and the like, which are decomposition products of the phenol resin, and tar components.
• the pre-baking temperature is preferably 300 ° C. or higher and lower than 800 ° C., more preferably 350 ° C. or higher and lower than 800 ° C., further preferably 400 ° C. or higher and 700 ° C. or lower, and particularly preferably 550 ° C. or higher and 700 ° C. or lower. ..
• the pre-baking temperature is less than 300 ° C, detaring becomes insufficient, and a large amount of tar and gas are generated in the main firing step after crushing, which may adhere to the particle surface and cause deterioration of battery performance. Sometimes.
• the pre-baking temperature is 800 ° C. or higher, the generated tar causes a secondary decomposition reaction, and these decomposition products adhere to the carbon precursor, and the carbonaceous material obtained by the carbon precursor is used as an electrode. In the non-aqueous electrolyte secondary battery used, the performance of the battery may deteriorate.
• Pre-baking can be performed in a non-oxidizing gas atmosphere.
• the non-oxidizing gas is not particularly limited as long as it is a gas that does not cause an oxidation reaction at the pre-calcination temperature.
• a rare gas such as helium or argon, or nitrogen can be mentioned, and these can be used alone or in combination.
• the pre-baking time is not particularly limited, and is preferably 30 minutes or more, more preferably 45 minutes or more, and particularly preferably 1 hour or more. Even if the pre-firing time is too long, there is no particular adverse effect, and considering the efficiency of thermal energy and non-oxidizing gas, the pre-firing time is preferably 20 hours or less.
• the pre-baking time means a residence time at 300 ° C. or higher and lower than 800 ° C. when performed in a continuous furnace, and a holding time at 300 ° C. or higher and lower than 800 ° C. when performed in a batch furnace. ..
• the pre-calcined charcoal obtained by pre-calcining the carbon precursor can be pulverized before the main calcining to have a particle size suitable for obtaining the carbonaceous material according to the present invention.
• the average particle size of the pre-calcined coal after crushing is not particularly limited. It is preferably less than 50 ⁇ m, more preferably less than 30 ⁇ m, and particularly preferably less than 20 ⁇ m.
• the average particle size of the pre-calcined coal after crushing is preferably 1 ⁇ m or more.
• the main firing in the production method of the present invention is a step of heating at 950 ° C. or higher and 1500 ° C. or lower in a non-oxidizing gas atmosphere.
• This main firing can be performed according to a normal main firing procedure. By performing this main firing, calcined charcoal can be obtained.
• a continuous reaction device such as a moving layer, a fluidized bed, and an air flow layer, which is not particularly limited, as long as the device can be heat-treated at 950 ° C. or higher in a non-oxidizing gas atmosphere.
• the lower limit of the firing temperature of the present invention is 950 ° C. or higher, more preferably 1050 ° C. or higher, further preferably 1100 ° C. or higher, and particularly preferably 1150 ° C. or higher.
• the main firing temperature sodium is likely to volatilize from the carbonaceous material.
• the main firing temperature is too low, carbonization may be insufficient and the irreversible capacity may increase. That is, a large amount of functional groups remain in the carbonaceous material, the H / C value becomes high, the difference between the doping capacity and the dedoping capacity increases due to the reaction with lithium, and the positive electrode lithium is wasted.
• the upper limit of the firing temperature of the present invention is 1500 ° C.
• the main firing temperature exceeds 1500 ° C., the voids formed as lithium storage sites may decrease, and the doping / dedoping capacity may decrease.
• This firing is preferably performed in a non-oxidizing gas atmosphere.
• the non-oxidizing gas include rare gases such as helium and argon, nitrogen and the like, and these can be used alone or in combination.
• the main firing can be performed under reduced pressure, and can be performed at, for example, 10 kPa or less.
• the holding time of the main firing is not particularly limited. In the case of batch firing, the time during which the object to be fired is held in the temperature range between the maximum temperature reached and a temperature 20 ° C lower than that temperature, and in the case of continuous firing, the maximum temperature and 20 ° C below that temperature. The time during which the object to be fired passes through the low temperature region is referred to as the "main firing time".
• the main firing temperature is preferably 1 minute or longer, more preferably 2 minutes or longer, for example 3 minutes or longer. It is not preferable from the viewpoint of energy efficiency to keep the temperature at the main firing temperature even after the carbonization reaction is completed.
• the main firing time is preferably 3 hours or less, more preferably 1 hour or less, further preferably 30 minutes or less, and particularly preferably 15 minutes or less.
• the production method according to the present invention includes a step of coating the calcined carbon obtained by the present calcining with pyrolytic carbon. Fine voids are formed in the calcined charcoal obtained by main calcining a resol type phenol resin as a carbon source by an alkali activation reaction. Although the details are not clear, the voids have pores that are incompatible with the storage of lithium, such as the ability of electrolyte to enter. Therefore, by coating the calcined charcoal with pyrolytic carbon, the voids can be arranged so as to form pores suitable for storing lithium, and as a result, the dedoping capacity of the secondary battery is significantly increased. be able to.
• CVD chemical vapor deposition
• the hydrocarbon which is the carbon source of the pyrolytic carbon used in the coating step according to the present invention is not particularly limited as long as it is a gas at the pyrolysis reaction temperature and can reduce the specific surface area of the calcined charcoal. ..
• Pyrolytic carbon derived from aromatic compounds can form a dense film and inhibit the diffusion of lithium. Therefore, an aliphatic hydrocarbon is preferable as the carbon source of the pyrolytic carbon. However, by controlling the CVD conditions, even pyrolytic carbon derived from an aromatic compound can be appropriately coated. Further, as the hydrocarbon gas, a gaseous organic substance and a hydrocarbon gas generated by heating and vaporizing a solid or liquid organic substance can also be used.
• the surface of the calcined coal can be coated with pyrolytic carbon.
• the hydrocarbon gas can be diluted with a non-oxidizing gas to form a mixed gas, and the thermal decomposition reaction can be controlled.
• a non-oxidizing gas nitrogen, a rare gas such as helium or argon, or a mixture thereof can be used. Since the hydrocarbon gas is thermally decomposed to form a film, it is necessary to control the reaction by the concentration of carbon atoms in the mixed gas. The concentration of carbon atoms in the hydrocarbon gas increases as the number of carbon atoms constituting the hydrocarbon increases.
• the concentration of carbon atoms in 1 mol of hexane is 72 g / mol (3.21 g / L (NTP)), and the concentration of carbon atoms in propane is 36 g / mol (1.61 g / L (NTP)). .. Even if the volume of the hydrocarbon gas is the same, hexane will contain twice as many carbon atoms as propane. If the concentration of carbon atoms in the mixed gas of the non-oxidizing gas and the hydrocarbon gas is too low, the amount of pyrolytic carbon produced is small, which is not preferable.
• the carbon atom concentration in the mixed gas is preferably 0.05 g / L (NTP) or more, more preferably 0.10 g / L (NTP) or more, and particularly preferably 0.15 g / L (NTP) or more.
• NTP 0.05 g / L
• the concentration of carbon atoms in the mixed gas is too high, a large amount of pyrolytic carbon adheres to the wall surface of the CVD processing furnace, and it becomes difficult to uniformly coat the calcined carbon with the pyrolytic carbon, which is not preferable.
• the temperature of the CVD treatment is not particularly limited, and is preferably 600 ° C. or higher and 1500 ° C. or lower, more preferably 650 ° C. or higher and 1000 ° C. or lower, and further preferably 700 ° C. or higher and 950 ° C. or lower.
• the contact time between the hydrocarbon gas and the calcined charcoal is not particularly limited, for example, preferably 10 minutes to 5.0 hours, more preferably 15 minutes to 3 hours.
• the preferred contact time depends on the calcined charcoal to be coated, and basically, as the contact time becomes longer, the specific surface area of the obtained carbonaceous material can be reduced. That is, it is preferable to carry out the coating treatment under the condition that the specific surface area of the obtained carbonaceous material is less than 30 m 2 / g.
• the specific surface area of the carbonaceous material can be controlled by adjusting the carbon atom concentration in the atmospheric gas, the CVD treatment temperature, the contact time between the hydrocarbon gas and the calcined charcoal, and the like.
• the apparatus used in the coating process according to the present embodiment is not particularly limited, and can be carried out by, for example, a continuous or batch type intra-layer distribution method using a flow bed using a flow furnace, a rotary kiln, or the like.
• the amount of gas supplied (distribution amount) is also not limited.
• the production method according to the present invention can include a washing step of washing the calcined charcoal and removing the sodium in order to wash and remove the sodium derived from the sodium-based basic catalyst in the resole-type phenol resin and the compound thereof. ..
• Such cleaning is not particularly limited and can be performed after the firing step. It is preferably performed on the calcined charcoal after the calcining step and before the coating step.
• the carbonaceous material becomes strongly alkaline. Further, if sodium remains in the carbonaceous material, sodium may move to the counter electrode when the secondary battery is discharged, which may adversely affect the charge / discharge characteristics. Therefore, it is preferable that the carbonaceous material has a small content of sodium and a sodium compound.
• a carbonaceous material having a large dedoping capacity can be obtained without adding a sodium compound to the carbon precursor.
• a carbonaceous material is a non-graphitic carbon material and has little expansion and contraction during lithium doping / dedoping. Therefore, when applied to an all-solid-state battery, it forms a stable interface structure with a solid electrolyte. It also has shape stability.
• Carbonate material for negative electrode of non-aqueous electrolyte secondary battery Carbonate material for negative electrode of non-aqueous electrolyte secondary battery
• the physical properties of the carbonaceous material for the negative electrode of the non-aqueous electrolyte secondary battery according to the present invention are not particularly limited.
• the true density measured by the butanol method is 1.20 to 1.60 g / cm 3 , nitrogen adsorption.
• the specific surface area determined by the BET method according to the above is 30 m 2 / g or less, the average particle size is 50 ⁇ m or less, and the atomic ratio (H / C) of hydrogen atom to carbon atom determined by elemental analysis is 0.1 or less.
• true density The true density of defect-free graphite crystals is 2.27 g / cm 3 , and the true density tends to decrease as the crystal structure is disturbed. Therefore, the true density is an index showing the carbon structure.
• the true density herein is measured by the butanol method.
• the true density of the carbonaceous material for the negative electrode of the non-aqueous electrolyte secondary battery according to the present invention is preferably 1.20 g / cm 3 to 1.60 g / cm 3 .
• the upper limit of the true density is more preferably 1.55 g / cm 3 or less, further preferably 1.50 g / cm 3 or less, particularly preferably 1.48 g / cm 3 or less, and most preferably Is 1.47 g / cm 3 or less.
• the lower limit of the true density is more preferably 1.25 g / cm 3 or more, further preferably 1.30 g / cm 3 or more, particularly preferably 1.35 g / cm 3 or more, and most preferably 1. .37 g / cm 3 or more.
• a carbonaceous material having a true density of more than 1.60 g / cm 3 may have a small pore volume capable of storing lithium and a small dedoping capacity.
• the electrolytic solution may penetrate into the pores and may not become a lithium storage site. Further, the structure of the carbonaceous material is gradually weakened, and the pore structure of carbon may be broken during electrode fabrication.
• the average particle size Dv50 of the carbonaceous material according to the present invention is preferably 1 to 50 ⁇ m.
• the lower limit of the average particle size is more preferably 1.5 ⁇ m or more, still more preferably 2.0 ⁇ m or more.
• the average particle size is less than 1 ⁇ m, the amount of fine powder increases, the reaction area with the electrolytic solution increases, lithium is consumed in the surface reaction between the electrolytic solution and the carbonaceous material, and the irreversible capacity is the capacity that does not discharge even when charged. Is not preferable because the amount of lithium in the positive electrode is increased and the ratio of wasted lithium in the positive electrode is increased.
• the upper limit of the average particle size is preferably 50 ⁇ m or less, more preferably 30 ⁇ m or less, still more preferably 20 ⁇ m or less, particularly preferably 15 ⁇ m or less, and most preferably 10 ⁇ m or less. If the average particle size exceeds 50 ⁇ m, the outer surface area decreases and rapid charging / discharging becomes difficult, which is not preferable.
• the average particle size DV50 means the particle size at the point where the cumulative curve is obtained from the small particle size to the large particle size, assuming that the total volume of the particles is 100%.
• the specific surface area of the carbonaceous material can be obtained by an approximate formula derived from the formula of BET by nitrogen adsorption.
• the specific surface area of the carbonaceous material according to the present invention is preferably 30 m 2 / g or less. When the specific surface area exceeds 30 m 2 / g, the amount of reaction between the carbonaceous material and the electrolytic solution increases, lithium in the positive electrode is wasted, and as a result, the irreversible capacity, which is the difference between the doped capacity and the dedoped capacity. May increase and the battery performance may decrease.
• the upper limit of the specific surface area is preferably less than 30 m 2 / g, more preferably less than 20 m 2 / g, particularly preferably less than 10 m 2 / g, and most preferably less than 5 m 2 / g.
• the lower limit of the specific surface area is preferably 0.1 m 2 / g or more, more preferably 0.5 m. It is 2 / g or more.
• DS is the particle size with respect to the specific surface area. It is an index of unaffected surface area.
• the DS is preferably 2 to 200 cm 3 / g. If the DS is less than 2 cm 3 / g, the dope area of lithium in the particles is small, which is not preferable.
• the DS is preferably 2 cm 3 / g or more, more preferably 5 cm 3 / g or more, particularly preferably 10 cm 3 / g or more, and most preferably 15 cm 3 / g. If the DS exceeds 200 cm 3 / g, the lithium storage sites in the particles are reduced, which is not preferable.
• the DS is preferably 200 cm 3 / g or less, more preferably 150 cm 3 / g or less, further preferably 100 cm 3 / g or less, and particularly preferably 50 cm 3 / g or less.
• the atomic ratio (H / C) of hydrogen atom to carbon atom is obtained from the content of hydrogen atom and carbon atom measured by elemental analysis. As the degree of carbonization increases, the hydrogen content of the carbonaceous material decreases, so that the H / C tends to decrease. Therefore, H / C is effective as an index showing the degree of carbonization.
• the H / C of the carbonaceous material according to the present invention is preferably 0.1 or less, more preferably 0.08 or less. Particularly preferably, it is 0.05 or less. When the H / C exceeds 0.1, many functional groups are present in the carbonaceous material, and the irreversible capacity may increase due to the reaction with lithium.
• the average layer spacing d 002 is more preferably 0.37 nm or more and 0.41 nm or less, and particularly preferably 0.37 nm or more and 0.40 nm or less.
• the method for manufacturing the non-aqueous electrolyte secondary battery electrode according to the present invention is the production of carbonaceous material for the negative electrode for non-aqueous electrolyte secondary battery described in the above [1]. After producing a carbonaceous material for the negative electrode of a non-aqueous electrolyte secondary battery by the method, a non-aqueous electrolyte secondary battery electrode is produced using the carbonaceous material for the negative electrode of the non-aqueous electrolyte secondary battery.
• an electrolytic solution is used as an electrolyte of a non-aqueous electrolyte secondary battery.
• a binder and a solvent are added to the carbonaceous material and kneaded to prepare an electrode mixture, and the electrode mixture is applied to a current collector and dried. After that, it can be produced by pressure molding. Further, for the purpose of imparting even higher conductivity, a conductive auxiliary agent can be added at the time of preparing the electrode mixture, if necessary.
• the amount of the above-mentioned conductive auxiliary agent added is preferably 0.5 to 15% by mass, while the total amount of the active material (carbonaceous material), the binder and the conductive auxiliary agent is 100% by mass. It may be 0.5 to 7% by mass or 0.5 to 5% by mass.
• the above binder is not particularly limited as long as it does not react with the electrolytic solution.
• the thicker the electrode active material layer the smaller the number of current collectors, separators, and the like, which is preferable from the viewpoint of increasing the capacity.
• the wider the electrode area facing the counter electrode is, the more advantageous it is to improve the input / output characteristics. Therefore, if the thickness of the electrode active material layer is excessive, the input / output characteristics are deteriorated, which is not preferable.
• the thickness of the active material layer per side is not limited, and is preferably in the range of 40 ⁇ m to 500 ⁇ m, and may be in the range of 40 to 400 ⁇ m or 50 to 350 ⁇ m.
• the negative electrode usually has a current collector.
• the current collector of the negative electrode is not particularly limited as long as it is a metal that does not elute in the potential change range during charging / discharging.
• a solid electrolyte is used as the electrolyte of the non-aqueous electrolyte secondary battery.
• a gel polymer material, an organic / inorganic solid electrolyte material, or the like is used as the electrolyte material.
• a solid electrolyte and the carbonaceous material of the present invention can be mixed and molded to produce a negative electrode.
• the above-mentioned binder and conductive auxiliary agent can be added, if necessary.
• the method for manufacturing the non-aqueous electrolyte secondary battery of the present invention is non-water using the non-aqueous electrolyte secondary battery electrode manufactured by the manufacturing method described in the above [2]. It is characterized by manufacturing an electrolyte secondary battery.
• a battery such as a positive electrode material, a negative electrode material, a separator (porous polymer film, solid electrolyte, etc.), electrolyte (electrolyte solution, solid electrolyte, etc.) is configured.
• the other materials used are not particularly limited, and various materials conventionally used or proposed as the non-aqueous electrolyte secondary battery can be used.
• the positive electrode contains a positive electrode active material, and may further contain a conductive auxiliary agent, a binder, and a solid electrolyte, if necessary.
• the mixing ratio of the positive electrode active material and the other material in the positive electrode active material layer is not limited as long as the effect of the present invention can be obtained, and can be appropriately selected.
• positive electrode active material a well-known positive electrode active material can be used without limitation.
• the positive electrode can further contain a conductive auxiliary agent and / or a binder.
• the content of each conductive auxiliary agent or binder is not limited, for example, 0.5 to 15% by mass.
• the positive electrode usually has a current collector.
• the current collector of the positive electrode is not particularly limited as long as it is a metal that does not elute in the potential change range during charging and discharging.
• the electrolytic solution is formed, for example, by dissolving an electrolyte salt in a non-aqueous solvent.
• a positive electrode layer and a negative electrode layer formed as described above are opposed to each other via a liquid-permeable separator made of a non-woven fabric, other porous material, or the like, if necessary, to form an electrolytic solution. It is formed by immersing it in it.
• Solid electrolyte is not particularly limited as long as it is a substance having ionic conductivity of lithium in a solid state.
• examples of the inorganic solid electrolyte include an oxide solid electrolyte and a sulfide solid electrolyte.
• separator As the separator, a permeable separator made of a non-woven fabric or other porous material can be used. Alternatively, instead of or in combination with such a separator, a polymer gel or an inorganic solid electrolyte impregnated with an electrolytic solution can be used.
• the optimum structure as a negative electrode material for a non-aqueous electrolyte secondary battery is, firstly, that the negative electrode material has voids capable of storing a large amount of lithium.
• various pores are widely distributed.
• the penetrating pores of the electrolyte are electrochemically corresponding to the outer surface and therefore do not provide a stable storage site for lithium.
• the lithium storage sites are pores in which the electrolytic solution is difficult to penetrate, and lithium can reach every corner of the pores when lithium is doped.
• the "pores in which lithium can reach every corner" include pores in which lithium can diffuse in the carbon particles, and in the process, lithium is generated while widening the surface spacing of the carbon hexagonal network plane.
• the pores may be capable of diffusing into the carbon.
• the optimum structure as a negative electrode material for a non-aqueous electrolyte secondary battery is secondly that the irreversible capacity, which is the difference between the lithium storage capacity and the dedoping capacity observed at the initial stage of the doping and dedoping reaction, is small. That is, the structure is such that the electrolyte decomposition reaction on the surface of the carbon particles is small. Since the graphitic material decomposes the electrolytic solution on the surface, a non-graphitic material is preferable. Further, it is known that the edge surface of the carbonaceous material is highly reactive. There is an activation method as a method for forming pores.
• Pore formation with an oxidizing agent such as water vapor is not preferable because pores are formed by oxidative decomposition of the carbon skeleton, and the carbon disappearance site becomes an edge surface.
• an oxidizing agent such as water vapor
• the formation of an edge surface can be suppressed because pores are formed by expanding the carbon layer surface.
• a structure in which the formation of the edge surface is suppressed in the process of forming the pore structure and the decomposition reaction of the electrolytic solution is small is preferable.
• the negative electrode material for a non-aqueous electrolyte secondary battery according to the present invention by firing a resole-type phenol resin using a sodium basic catalyst, an alkali activation reaction with sodium occurs at the time of firing, while suppressing the formation of an edge surface. A pore structure is formed. Further, the obtained calcined charcoal is heat-treated in an atmosphere containing an aliphatic hydrocarbon, so that the pyrolytic carbon generated from the aliphatic aliphatic carbon is coated in the pores, and the edge surface having high reactivity is coated. The formation is reduced and the optimal pore structure for lithium storage is formed. Therefore, it is considered that the negative electrode material for a non-aqueous electrolyte secondary battery according to the present invention has a structure having voids capable of storing a large amount of lithium in the negative electrode material.
• Example preparation Each sample of carbonaceous material was prepared by the production method shown below. The preparation conditions are shown in Table 1.
• Example 1 After 200 g of phenol and 177.3 g of 36 mass% formalin were placed in a separable flask and mixed, 20 g of a 30 mass% sodium hydroxide aqueous solution was further added, and the mixture was held at 85 to 95 ° C. for 4.5 hours with stirring for addition condensation. The reaction was carried out. After the addition condensation reaction was completed, the mixture was allowed to cool to room temperature to obtain an initial condensate. The initial condensate was heated at 150 ° C. for 7 hours to proceed with the dehydration condensation reaction to obtain a resol type phenol resin.
• the resole-type phenol resin was crushed and sieved to obtain particles having a particle size of 297 to 500 ⁇ m, and the particles were placed in a vertical tube furnace with a perforated plate at 400 ° C. in a nitrogen stream. Pre-baking was performed for 10 hours.
• the obtained pre-calcined coal was pulverized by a rod mill to obtain powdered pre-calcined coal.
• the powdered pre-calcined charcoal was charged into a horizontal tube furnace, held at 1110 ° C. for 1 hour in a nitrogen stream for main firing, and then cooled to obtain calcined charcoal.
• Example 2 A carbonaceous material sample was produced by the same procedure as in Example 1 except that the main firing temperature was set to 1200 ° C.
• Example 3 The procedure was the same as in Example 2 except that the amount of 36 mass% formalin used was 354.5 g and the retention time of the condensation condensation reaction (reaction at a temperature of 85 to 95 ° C.) was 1.5 hours. To produce a carbonaceous material sample.
• Example 4 A carbonaceous material sample was produced by the same procedure as in Example 2 except that the amount of the 30 mass% sodium hydroxide aqueous solution used was 33.4 g and the reaction time of the condensation condensation reaction was 4.5 hours. bottom.
• Example 5 A carbonaceous material sample was produced by the same procedure as in Example 2 except that the amount of the 30 mass% sodium hydroxide aqueous solution used was 6.7 g.
• Example 6 The amount of 36% formalin used was 88.6 g, the reaction at a temperature of 85 to 95 ° C. was set to 6 hours, and 50 ml of propane gas and 100 ml of nitrogen gas were used as a coating method for pyrolytic carbon on calcined charcoal.
• a carbonaceous material sample was produced by the same procedure as in Example 2 except that the mixed gas of No. 2 was reacted at 750 ° C. for 30 minutes to coat the calcined charcoal with pyrolytic carbon.
• Example 7 As a method for coating the charcoal with pyrolytic carbon, a mixed gas of 50 ml of butane gas and 100 ml of nitrogen gas was reacted at 750 ° C. for 30 minutes, and the charcoal was coated with pyrolytic carbon. A carbonaceous material sample was produced by the same procedure.
• Example 8 A carbonaceous material sample was produced by the same procedure as in Example 2 except that the obtained calcined charcoal was further stirred in 2% by mass hydrochloric acid at 90 ° C. for 2 hours, washed with water and dried.
• Example 9 Example 2 and Example 2 except that 40 g of a 25 mass% sodium hydrogen carbonate aqueous solution dissolved in warm water was added instead of 20 g of a 30 mass% sodium hydroxide aqueous solution, and the retention time of the addition condensation reaction was set to 6 hours. A carbonaceous material sample was produced by the same procedure.
• Example 1 A carbonaceous material sample was produced by the same procedure as in Example 2 except that the calcined charcoal was not coated with pyrolytic carbon.
• Example 4 A carbonaceous material sample was produced by the same procedure as in Example 2 except that the 30% by mass sodium hydroxide aqueous solution was changed to a 30% potassium hydroxide aqueous solution and the preliminary firing was performed at 650 ° C. for 2 hours.
• pre-calcined coal was crushed by a rod mill to obtain powdered pre-calcined coal.
• the powdered pre-calcined charcoal was charged into a horizontal tube furnace, held at 1200 ° C. for 1 hour in a nitrogen stream, main calcined, and then cooled to produce a carbonaceous material sample.
• naphthalene was extracted and removed from the spherical pitch molded product with n-hexane to obtain a porous spherical pitch. Then, the porous spherical oxidation pitch was oxidized with heated air to obtain a porous spherical oxidation pitch insoluble in heat.
• the oxygen content (oxygen cross-linking degree) of the porous spherical oxidation pitch was 13% by mass.
• the infusible porous spherical oxidation pitch was pulverized by a jet mill (AIR JET MILL; MODEL 100AFG of Hosokawa Micron Co., Ltd.), and a pulverized carbonaceous precursor having an average particle size of 20 to 25 ⁇ m (pulverized carbon precursor).
• Body got.
• the obtained pulverized carbonaceous precursor is impregnated with an aqueous solution of sodium hydroxide (NaOH) and then subjected to heat dehydration treatment under reduced pressure to obtain 7.0% by mass of NaOH with respect to the pulverized carbonaceous precursor.
• An impregnated ground carbonaceous precursor was obtained.
• Comparative Example 8 5 g of the carbonaceous material produced in Comparative Example 7 was placed in a quartz reaction tube, heated and held at 750 ° C. under a nitrogen gas stream, and then the nitrogen gas circulating in the reaction tube was combined with hexane and nitrogen gas. By substituting the mixed gas of the above, the calcined charcoal was coated with pyrolysis carbon. The injection rate of hexane is 0.3 g / min, and after injecting for 30 minutes, the supply of hexane is stopped, the gas in the reaction tube is replaced with nitrogen, and then allowed to cool, and carbon coated with pyrolytic carbon. Quality material samples were produced.
• Comparative Example 9 A carbonaceous material sample was produced by the same procedure as in Comparative Example 5 except that the calcined charcoal was not coated with pyrolytic carbon.
• the specific surface area was measured by the BET (Brunauer, Emmett and Teller) one-point method in accordance with the method specified in JIS Z8830: 2013 (ISO9277: 2010) "Method for measuring the specific surface area of powder (solid) by gas adsorption". ..
• the amount of adsorbed gas was measured using the carrier gas method.
• the sample tube is filled with the sample tube, and the sample tube is cooled to -196 ° C. while flowing helium gas containing nitrogen gas at a concentration of 20 mol%, and nitrogen is adsorbed on the sample.
• the test tube is then returned to room temperature.
• the amount of nitrogen desorbed from the sample was measured with a thermal conductivity type detector and used as the amount of adsorbed gas.
• the molecular cross-sectional area of nitrogen was 0.162 nm 2 .
• True density True density was measured using 1-butanol according to the method defined in JIS R7212: 1995. The outline will be described below.
• the specific density bottle is filled with 1-butanol, stoppered and immersed in a constant temperature water tank (adjusted to 30 ⁇ 0.03 ° C.) for 15 minutes or more, and the liquid level of 1-butanol is aligned with the marked line.
• the specific density bottle is taken out from the constant temperature water tank, the outside of the specific gravity bottle is thoroughly wiped, cooled to room temperature, and then its mass (m 4 ) is accurately weighed.
• d is the specific gravity (0.9946) of water at 30 ° C.
• Average particle size DV50 Average particle size DV50
• a dispersant cationic surfactant "SN Wet 366” (manufactured by San Nopco Ltd.)
• SN Wet 366 cationic surfactant "SN Wet 366” (manufactured by San Nopco Ltd.)
• 30 mL of pure water was added and dispersed for about 2 minutes with an ultrasonic cleaner, and then a particle size distribution measuring device (“MT3300EX” manufactured by Microtrac Bell Co., Ltd.) was used to measure the particle size in the range of 0.021 to 2000 ⁇ m.
• the peak position of the (002) diffraction line is determined by the center of gravity method (a method of obtaining the position of the center of gravity of the diffraction line and obtaining the peak position by the corresponding 2 ⁇ value), and the (111) diffraction line of the high-purity silicon powder for a standard substance.
• d 002 was calculated by the following Diffraction formula.
• the carbonaceous material according to the present invention is suitable for use as a negative electrode of a non-aqueous electrolyte secondary battery.
• the doped capacity, the dedoped capacity and the non-dedoped capacity of the battery active material are accurately evaluated without being affected by the variation in the performance of the counter electrode. Therefore, a lithium secondary battery having a lithium metal having stable characteristics as a negative electrode and a carbonaceous material obtained above as a positive electrode was constructed, and the battery characteristics were evaluated.
• the positive electrode (carbon electrode) was manufactured as follows. N-Methyl-2-pyrrolidone was added to 90 parts by weight of the carbonaceous material samples of Examples 1 to 9 and Comparative Examples 1 to 9 and 10 parts by weight of polyvinylidene fluoride to prepare a paste-like coating liquid. The coating liquid is uniformly applied onto the aluminum foil, dried, and then the formed coating film is peeled off from the aluminum foil and punched into a disk shape having a diameter of 15 mm to prepare a disk-shaped carbonaceous film. bottom.
• a stainless steel mesh disk having a diameter of 16 mm is spot-welded to the inner lid of a coin-type battery can of 2016 size (that is, a diameter of 20 mm and a thickness of 1.6 mm), and then the above disk is formed on the mesh disk.
• the carbonaceous film was pressed by pressing with a press and pressure-bonded to prepare a positive electrode.
• the amount of carbonaceous material in the positive electrode (carbon electrode) was set to about 20 mg.
• the negative electrode (lithium electrode) was prepared in a glove box in an argon atmosphere.
• a thin metal lithium plate having a thickness of 0.5 mm was punched into a disk shape having a diameter of 15 mm.
• a press to press to press to press the negative electrode.
• LiClO 4 was dissolved in a mixed solvent in which propylene carbonate and dimethoxyethane were mixed at a volume ratio of 1: 1 as an electrolytic solution at a ratio of 1 mol / liter.
• a 2016 size coin-type non-aqueous solvent-based lithium secondary battery was assembled in an argon glove box using a fine pore film made of polypropylene as a separator and a gasket made of polyethylene.
• the positive electrode made of a carbonaceous material was doped with lithium and dedoped with lithium, and the capacity at that time was determined.
• Lithium doping was carried out by repeating the operation of energizing with a current density of 0.5 mA / cm 2 for 1 hour and then resting for 2 hours until the equilibrium potential between the terminals became 4 mV.
• the value obtained by dividing the amount of electricity at this time by the weight of the carbonaceous material used was defined as the dope capacity and expressed in units of Ah / kg.
• an electric current was passed in the reverse direction to dedoping the doped lithium of the carbonaceous material.
• dedoping the operation of energizing with a current density of 0.5 mA / cm 2 for 1 hour and then resting for 2 hours was repeated, and the terminal voltage of 1.5 volts was set as the cutoff voltage.
• the value obtained by dividing the amount of electricity at this time by the weight of the carbonaceous material used was defined as the dedoping capacity and expressed in units of Ah / kg.
• the carbonaceous materials of Examples 1 to 9 were produced by a production method included in the scope of the present invention, and in each case, a sodium compound was added to the carbon precursor. It was possible to obtain a carbonaceous material having a large dedoping capacity without any problem.
• Comparative Examples 1 to 9 were produced by a production method outside the scope of the present invention.
• the calcined coal was not coated with pyrolytic carbon.
• the firing temperature was lower than the temperature range of the present invention.
• the firing temperature was higher than the temperature range of the present invention.
• the catalyst used in the addition condensation step was different from the sodium-based basic catalyst of the present invention.
• Comparative Examples 7 and 8 were pitch-derived carbonaceous materials, which were different from the phenolic resin-derived carbonaceous material of the present invention in the material of the carbon precursor. Therefore, Comparative Examples 1 to 9 had a smaller dedoping capacity than the carbonaceous materials of Examples 1 to 9.
• Comparative Example 5 and Comparative Example 9 and the difference between Comparative Example 7 and Comparative Example 8 are only the presence or absence of the coating treatment of pyrolytic carbon. In these comparative examples, the effect of capacity improvement by the coating treatment was not obtained.
• a carbonaceous material having a large dedoping capacity can be obtained without adding a sodium compound to the carbon precursor.
• the carbonaceous material thus obtained is useful as an active material for the negative electrode of a non-aqueous electrolyte secondary battery such as an all-solid-state battery.

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