JP5680191B2 - Composite hard carbon negative electrode material for lithium ion battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a battery negative electrode material and a manufacturing method thereof, and more particularly to a negative electrode material of a lithium ion battery and a manufacturing method thereof.

  With the increasing demand for multifunctional portable electronic devices in the information age and the rapid development of electric vehicles, research on electrode materials for new lithium batteries with high specific energy, high rate, high safety, long life and low cost・ Development has become an important cutting-edge research field internationally. Relatively successful carbon anode materials in the prior art include artificial graphite, mesophase carbon microbeads (MCMB), and petroleum coke, but the specific capacity of 372 mAh / g is too low to satisfy the requirements. It has a very limited stability due to its fragile structure and is very sensitive to electrolytes. For this reason, other carbon materials such as soft carbon and hard carbon have attracted attention. Among them, hard carbon has attracted attention due to its high capacity, low cost and excellent cycle performance due to its irregular arrangement. Hard carbon refers to carbon that is difficult to graphitize, and is pyrolytic carbon of a high molecular polymer, and such carbon has a relatively high specific capacity. In 1991, Sony Corporation developed a lithium-ion battery using hard carbon produced by thermal decomposition of polyfurfuryl alcohol PFA as a negative electrode material. However, its initial charge / discharge efficiency is low, only about 45%.

  An object of the present invention is to provide a composite hard carbon negative electrode material for a lithium ion battery and a method for producing the same. The technical problem to be solved improves the high rate charge / discharge performance of the lithium ion battery and is excellent. It is to achieve both high and low temperature charge / discharge performance and stable cycle performance.

The present invention employs the following technical solution.
A composite hard carbon negative electrode material of a lithium ion battery, wherein a coating substance is coated on the outside of the hard carbon substrate of the composite hard carbon negative electrode material of the lithium ion battery, and a precursor of the coating substance is an organic resin epoxy resin, phenolic resins, carboxymethyl cellulose, pitch, ethyl methyl carbonate, polyvinyl alcohol, polystyrene, Po Rifu' fluoride, polypropylene oxide, polyethylene succinate, polyethylene sebacate, Po Li acetylene, polyparaphenylene, Po Ripiroru, Po Li thiophene, poly is a (p- phenylenevinylene) and polyimide 1 or more, they form a pyrolyzed coating materials.

Precursor of the hard carbon substrate in the present invention, acrylic resin, polyvinyl chloride resin, and a polycarbonate, epoxy resins, one or more phenolic resins and poly formaldehyde, they thermally decompose to form a hard carbon substrate The mass of the coating material precursor is 1 to 15% of the mass of the precursor of the hard carbon substrate, and the composite hard carbon negative electrode material of the lithium ion battery has a porous structure with fine particles having a massive shape and a pore size. 0.2～1OOnm, porosity 9~19%, 0.338~0.475nm interlayer distance 002 crystal plane, the particle size range 0.5～90Myuemu, specific surface area of 1.9~75.3m ² / g, a true density of 1.54~2.35g / Cm ³ , the tap density is 0.88 to 1.43 g / cm ³ , and the carbon element content is 90.5% or more.

The precursor of the hard carbon substrate in the present invention is composed of 25% by mass to less than 100% by mass of the resin, and more than 0% by mass and 75% by mass or less of the curing agent, which are thermally decomposed to form a hard carbon substrate. The curing agent is at least one of hexamethylenediamine, m-phenylenediamine, aniline formaldehyde resin, polyamide resin, polyformaldehyde, phthalic anhydride and benzenesulfonic acid.

The precursor of the hard carbon substrate in the present invention comprises 25% by mass to less than 100% by mass of the resin, more than 0% by mass to 75% by mass curing agent, and more than 0% by mass to 15% by mass dopant. , they thermally decompose to form a hard carbon substrate, wherein the dopant is at least one of elemental metals, metallic compounds and non-metal compounds, wherein the simple metal is tin, the metal compound is sodium-phosphate not less than one salt of tin hydroxide and scan's, before Symbol nonmetal compound is phosphorus pentoxide, boric acid, Li phosphate ammonium and silicone resins 1 or more.

The precursor of the hard carbon substrate in the present invention is composed of the resin of 85% by mass to less than 100% by mass and the dopant of more than 0% by mass and 15% by mass or less, and they are thermally decomposed to form a hard carbon substrate. the dopant metal alone, is one or more metallic compounds and non-metal compounds, wherein the simple metal is tin, the metal compound is sodium-phosphate, one or more salts of tin hydroxide and scan's There, before Symbol nonmetal compound is phosphorus pentoxide, boric acid, Li phosphate ammonium and silicone resins 1 or more.

The precursor of the hard carbon substrate in the present invention is at least one of plant materials such as pollen, rice husk, sweet potato stalk, walnut husk, bamboo, sake lees, and wood chips, which are pyrolyzed to form a hard carbon substrate, which is coated The mass of the precursor of the material is 1 to 25% by mass of the precursor of the hard carbon substrate, the surface of the hard carbon substrate and the coating material are bonded by chemical bonding or van der Waals force, and the hard carbon substrate has a particle size of 2 -60 μm with a honeycomb pore structure on the surface, a pore size of 1.0-55 nm, the material is a massive and / or flaky particle, the particle size is 3.5-70 μm, the specific surface area is 7.5- 20 m ² / g, having a honeycomb-like pore structure on the material surface, pore diameter of 0.2 to 60 nm, porosity of 9 to 16%, interlayer distance of 002 crystal plane d ₀₀₂ value of 0.337 to 0.455 nm , true density of 1.55~2.25g / cm ^3, a tap density of 0.91~1.45g / cm ^3, the carbon element Yes amount is equal to or greater than 94%.

The precursor of the hard carbon substrate in the present invention is a mixture of a plant raw material and a dopant occupying 40% by mass or less of the plant raw material, and they are thermally decomposed to form a hard carbon substrate, the dopant gold Shokushio der Ru salts of tin and carbon cobalt in one or more, non-metal oxides der sulfo window or acid, non-metallic salts der ruri phosphate ammonium or arm, non-metallic elemental Or silicon resin which is a non-metallic compound .

A method for producing a composite hard carbon negative electrode material for a lithium ion battery, wherein the resin is cured in air at room temperature for 3 to 50 hours to obtain a solid precursor, and the flow rate of nitrogen gas is 0.1 to 0.4 m ³ / h. The precursor is heated to 150 ° C. to 450 ° C. at a rate of 0.1 to 3 ° C./min, pre-sintered at a low temperature for 2 to 24 hours, naturally cooled to room temperature, and pulverized to obtain a powder having a particle size of 1 to 60 μm. Step 2 and the flow rate of nitrogen gas is 0.1 to 0.4 m ³ / h, the temperature is raised to 560 to 1500 ° C. at a rate of 0.3 to 10 ° C./min, pyrolyzed for 0.5 to 7.5 h, and the temperature is naturally lowered to room temperature. Step 3 for obtaining hard carbon, Step 4 for ball milling or pulverizing the hard carbon to obtain a hard carbon substrate having a particle size of 1 to 60 μm, and a precursor of the coating material to the hard carbon substrate 1 added in an amount of 15 mass%, was 20~50min mixed at a rotational speed of 1400~3500r / min, the flow rate of nitrogen gas 0.1 to 0.4 m 3 ^/ h Then, the temperature is raised to 500-1500 ° C. at a rate of 1-7.5 ° C./min, the coating material is pyrolyzed for 2-8 hours, and the temperature is naturally lowered to room temperature to obtain a composite hard carbon negative electrode material for a lithium ion battery. Wherein the resin is at least one of acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, phenol resin and polyformaldehyde, and the precursor of the coating material is an organic epoxy resin, phenol resin, Carboxymethyl cellulose, pitch, ethyl methyl carbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, butadiene-styrene rubber, polyvinyl chloride, polyethylene, polyethylene oxide, polypropylene oxide, polyethylene resin Sinate, polyethylene sebacate, polyethylene glycol imine, polyacetylene, polyparaphenylene, polyaniline, polypyrrole, polyacene, poly-m-phenylenediamine, polythiophene, poly (p-phenylene vinylene), polythiophene, polyacrylonitrile, polyimide and polyphenylene sulfide One or more.

In the method of the present invention, as curing, a curing agent of more than 0% by mass and 75% by mass or less is added to a resin of 25% by mass to less than 100% by mass, stirred uniformly, and in air at room temperature for 3 to 50 hours. A solid precursor is obtained by curing, and the curing agent is at least one of hexamethylenediamine, m-phenylenediamine, aniline formaldehyde resin, polyamide resin, phthalic anhydride and benzenesulfonic acid.

  In the method of the present invention, following the low temperature pre-sintering and pulverization, the dopant is added to the powder at a ratio of more than 0% by mass and 15% by mass or less, and mixed and stirred for 26 to 120 minutes at a rotational speed of 1000 to 3000 r / min. The dopant is one or more of a metal simple substance, a non-metal simple substance, a metal compound and a non-metal compound, the metal simple substance is one or more of copper, lead, antimony, tin, cobalt and nickel, and the metal compound is oxidized. One or more of tin, cobalt oxide, nickel oxide, sodium phosphate, sodium dihydrogen phosphate, tin acetate, tin oxide, cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, Nonmetallic simple substance is one or more of silicon, sulfur and boron, and the nonmetallic compound is silicon dioxide, phosphorus pentoxide, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, phosphorus Ammonium sulfate, is one or more silicone resins and ethylene glycol borate ester.

In the method of the present invention, as curing, 25% by mass to less than 100% by mass of a resin is added with a curing agent of more than 0% by mass to 75% by mass and a dopant of more than 0% by mass to 15% by mass, 2000 The mixture is stirred for 10 to 120 minutes at a rotational speed of ~ 4500 r / min and cured in air at room temperature for 3 to 50 hours to obtain a precursor. The dopant is one of a simple metal, a non-metal simple substance, a metal compound and a non-metal compound. The metal simple substance is one or more of copper, lead, antimony, tin, cobalt and nickel, and the metal compound is tin oxide, cobalt oxide, nickel oxide, sodium phosphate, sodium dihydrogen phosphate, acetic acid. One or more of tin, tin chloride, cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, and the non-metal simple substance is one or more of silicon, sulfur and boron, and the non-metal Compound is Silicon oxide, phosphorus pentoxide, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate, ammonium sulfate, at least one silicone resin and ethylene glycol borate ester.

  In the method of the present invention, following low-temperature pre-sintering, a dopant is added at a rate of more than 0% by mass and 15% by mass or less, and mixed and stirred at a rotational speed of 1000 to 3000 r / min for 26 to 120 minutes. , One or more of a non-metal simple substance, a metal compound and a non-metal compound, and the metal simple substance is one or more of copper, lead, antimony, tin, cobalt and nickel, and the metal compound is tin oxide, cobalt oxide, One or more of nickel oxide, sodium phosphate, sodium dihydrogen phosphate, tin acetate, tin chloride, cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, and the non-metal element is silicon One or more of sulfur and boron, and the non-metallic compound is silicon dioxide, phosphorus pentoxide, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate Ammonium sulfate, is one or more silicone resins and ethylene glycol borate ester.

A method for producing a composite hard carbon negative electrode material for a lithium ion battery, comprising a resin of 85 mass% to less than 100 mass% and a dopant of greater than 0 mass% to 15 mass% or less at a rotational speed of 2000 to 4500 r / min. And stirring for 10 to 120 minutes and curing in air at room temperature for 1 to 6 hours to obtain a solid precursor, and the flow rate of nitrogen gas is 0.1 to 0.4 m ³ / h, and the precursor is 0.1 to 7 ° C./hour The temperature is raised from 150 ° C. to 450 ° C. at a rate of min, pre-sintered at a low temperature for 3 to 24 hours, and naturally cooled to room temperature, and the flow rate of nitrogen gas is 0.1 to 0.4 m ³ / h, and 0.3 to 10 The temperature is raised to 560-1500 ° C. at a rate of ℃ / min, pyrolyzed for 0.5-7.5 h, naturally cooled to room temperature to obtain hard carbon, and the hard carbon is ball milled or crushed, and the particle size is 1-60 μm. Step 4 for obtaining a hard carbon substrate, and an amount of 1-15% by mass of the precursor of the hard carbon substrate with the precursor of the coating material applied to the hard carbon substrate. In addition, after 20~50min mixed at a rotational speed of 1400~3500r / min, the flow rate of nitrogen gas as 0.1 to 0.4 m 3 ^{/ h,} warmed to 500 to 1500 ° C. at a rate of 1 to 7.5 ° C. / min, 2 to 8 h, pyrolyzing the coating material, allowing it to cool naturally to room temperature, and obtaining a composite hard carbon negative electrode material for a lithium ion battery, wherein the resin is an acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, It is at least one of phenol resin and polyformaldehyde, and the dopant is at least one of metal simple substance, non-metal simple substance, metal compound and non-metallic compound, and the metal simple substance is copper, lead, antimony, tin, cobalt and nickel. And the metal compound is tin oxide, cobalt oxide, nickel oxide, sodium phosphate, sodium dihydrogen phosphate, tin acetate, tin chloride, cobalt carbonate, water One or more of copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, the non-metallic simple substance is one or more of silicon, sulfur and boron, and the non-metallic compound is silicon dioxide, phosphorus pentoxide, Boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate, ammonium sulfate, silicone resin and ethylene glycol borate ester, precursor of the coating material is an organic epoxy resin, phenol Resin, carboxymethyl cellulose, pitch, ethyl methyl carbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, butadiene-styrene rubber, polyvinyl chloride, polyethylene, polyethylene oxide, poly Lopylene oxide, polyethylene succinate, polyethylene sebacate, polyethylene glycol imine, polyacetylene, polyparaphenylene, polyaniline, polypyrrole, polyacene, poly-m-phenylenediamine, polythiophene, poly (p-phenylene vinylene), polythiophene, polyacrylonitrile, polyimide And at least one of polyphenylene sulfide.

A method for producing a composite hard carbon negative electrode material for a lithium ion battery, wherein 80 to 300 ml of acid or alkali is added to dry plant raw material per 100 g and immersed for 3 to 50 hours, and the plant raw material is pollen, rice husk, sweet potato stem, A step of one or more of walnut shell, bamboo, sake lees and wood chips, wherein the acid is hydrofluoric acid, boric acid, sulfuric acid, hydrochloric acid or nitric acid, and the alkali is potassium hydroxide, calcium hydroxide or sodium hydroxide 1. Washing process using pure water for 8-30 min at a rotation speed of 800-1400 r / min, washing process 2 and removing moisture and drying at 80-140 ° C. for 10-40 h until room temperature Step 3 where the temperature is naturally lowered, and a vacuum of 0.03 MPa or less, or under a protective gas of helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas, with a flow rate of 0.1 to 0.4 m ³ / h, 0.1 to 10 The temperature is raised to 200-500 ° C at a rate of ℃ / min and the temperature is lowered for 3-20h. Step 4 of low temperature pre-sintering to perform preliminary sintering and let the inside of the furnace cool down to room temperature, Step 5 to obtain a powder having a particle size of 1 to 60 μm by pulverization, and a degree of vacuum of 0.03 MPa or less, or helium gas Under a protective gas of nitrogen gas, argon gas, xenon gas or nitrogen gas, the flow rate is 0.1 to 0.4 m ³ / h, and the temperature is raised to 500 to 1300 ° C. at a rate of O.1 to 1 O ° C./min. ~ 1Oh pyrolysis, step 6 to cool the furnace naturally to room temperature, step 7 to obtain a hard carbon substrate having a particle size of 2 to 65 µm by pulverization or ball mill, and a precursor of the coating material to the hard carbon substrate. After adding 1 to 25% by mass of the precursor and mixing for 2 to 40 min at a rotational speed of 1000 to 4500 r / min, with a vacuum of 0.03 MPa or less, or helium gas, nitrogen gas, argon gas, xenon gas or under protective gas such as nitrogen gas, the flow rate of 0.1 to 0.4 m 3 ^{/ h,} speed of 0.1 to 10 ° C. / min The temperature is raised to 400 to 1300 ° C., pyrolyzed for 1 to 24 hours, the inside of the furnace is naturally cooled to room temperature, and the precursor of the coating material is an organic epoxy resin, phenol resin, carboxymethyl cellulose, pitch, ethyl Methyl carbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, butadiene-styrene rubber, polyvinyl chloride, polyethylene, polyethylene oxide, polypropylene oxide, polyethylene succinate, polyethylene sebacate, Polyethylene glycol imine, polyacetylene, polyparaphenylene, polyaniline, polypyrrole, polyacene, poly-m-phenylenediamine, polythiophene, poly (p-phenylene vinylene), poly Including thiophene, polyacrylonitrile, it is polyimide and polyphenylenesulfide 1 or more, and step 8, and steps 9 to obtain a composite hard carbon negative electrode material of the lithium ion battery of granularity 3.5~70μm toward 200 mesh sieve.

  In the method of the present invention, 80 to 300 ml of acid or alkali is added to 100 g of dried plant material per 100 g, and before immersing for 3 to 50 hours, the dried plant material that is a precursor is mechanically pulverized or jet milled to obtain a particle size of 40 to 1OO μm. After obtaining the powder, following the low-temperature pre-sintering pulverization, the dopant occupying more than 0% by mass and adding 40% by mass or less of the dopant, mixing and stirring for 20 to 95 minutes at a rotational speed of 1000 to 4500 r / min, Is one or more metal oxides such as tin oxide, cobalt oxide and nickel oxide, or one or more metal salts such as sodium phosphate, tin chloride, cobalt carbonate and sodium dihydrogen phosphate, or water which is metal alkali. One or more of copper oxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, or non-metal oxide silicon dioxide and / or phosphorus pentoxide, or one or more of boric acid, silicic acid and phosphoric acid, One or more of metal salts ammonium dihydrogen phosphate, ammonium phosphate and ammonium sulfate, or silicone resin and / or ethylene glycol borate ester, or metals such as copper, lead, antimony, tin, cobalt and nickel Or one or more of silicon, sulfur and boron which are non-metallic simple substances.

  In the method of the present invention, 80 to 300 ml of acid or alkali is added to 100 g of dry plant raw material per 100 g, mixed and stirred for 3 to 30 minutes at a rotational speed of 1000 to 3000 r / min, then immersed for 3 to 50 hours, and the low-temperature presintering And pulverizing, adding a dopant having a proportion of more than 0% by weight and not more than 40% by weight in the powder, mixing for 20 to 95 minutes at a rotational speed of 1000 to 4500 r / min, the dopant being tin oxide which is a metal oxide, One or more of cobalt oxide and nickel oxide, or one or more of metal salts such as sodium phosphate, tin chloride, cobalt carbonate and sodium dihydrogen phosphate, or metal alkali such as copper hydroxide, cobalt hydroxide, hydroxide One or more of tin and nickel hydroxide, non-metal oxide silicon dioxide and / or phosphorus pentoxide, or one or more of boric acid, silicic acid and phosphoric acid, or non-metal salt dihydrogen phosphate Ammonium, phosphorus One or more of ammonium acid and ammonium sulfate, or a silicone resin and / or ethylene glycol borate, or one or more of copper, lead, antimony, tin, cobalt, and nickel, or a non-metal simple substance One or more of certain silicon, sulfur and boron.

  In the method of the present invention, 80 to 300 ml of acid or alkali is added to 100 g of dried plant material per 100 g, and before immersing for 3 to 50 hours, the dried plant material that is a precursor is mechanically pulverized or jet milled to obtain a particle size of 40 to 1OO μm. A powder is obtained, and before the low-temperature pre-sintering, a dopant with a ratio of more than 0% by mass to 40% by mass or less is added and mixed at a rotational speed of 1000-4500 r / min for 20-95 min. One or more metal oxides such as tin oxide, cobalt oxide and nickel oxide, or one or more metal salts such as sodium phosphate, tin chloride, cobalt carbonate and sodium dihydrogen phosphate, or metal hydroxide which is a metal alkali One or more of copper, cobalt hydroxide, tin hydroxide and nickel hydroxide, non-metal oxide silicon dioxide and / or phosphorus pentoxide, or one or more of boric acid, silicic acid and phosphoric acid, Metal salt One or more of certain ammonium dihydrogen phosphates, ammonium phosphates and ammonium sulfates, or one or more of copper, lead, antimony, tin, cobalt and nickel as simple metals, or silicon, sulfur and boron as simple metals It is 1 or more types.

  The present invention obtains a composite hard carbon negative electrode material by subjecting a precursor of a hard carbon substrate to high temperature pyrolysis and coating as compared with the prior art, and the initial reversible capacity is 455.2 mAh / g at 0.2C. As described above, the initial coulomb efficiency is 79.4% or more, has excellent lithium insertion / extraction ability and cycle stability, and the hard carbon negative electrode material has the advantages of high capacity, high initial coulomb efficiency and high rate. The process is simple and easy to operate, and the cost is low. It is suitable for lithium ion power batteries, various portable devices, power tools, and lithium ion battery anode materials for electric vehicles.

2 is a scanning electron microscope image of Example 1. FIG. 2 is an X-ray diffraction image of Example 1. FIG. 2 is a graph of initial charge / discharge performance at different rates in Example 1; 2 is a graph of cycle performance of Example 1 at 60 ° C. and a 0.2 C rate. 2 is a graph of cycle performance in Example 1 at −30 ° C. and a 0.2 C rate. 18 is a scanning electron microscope image of the material produced in Example 14. FIG. 18 is an X-ray diffraction image of the material manufactured in Example 14. FIG. FIG. 16 is a graph of initial charge (lithium desorption) discharge (lithium insertion) performance at different rates for the material produced in Example 14. FIG. 14 is a graph of cycle performance of the material produced in Example 14 at 60 ° C. and 0.2 C rate. 14 is a graph of cycle performance of the material manufactured in Example 14 at −30 ° C. and 0.2 C rate.

  Hereinafter, the present invention will be described in more detail with reference to the drawings and embodiments. The composite hard carbon negative electrode material of the lithium ion battery of the present invention is an epoxy resin, phenol resin, carboxymethyl cellulose CMC, pitch, ethyl methyl carbonate, in which the coating material is coated on the outside of the hard carbon substrate, and the precursor of the coating material is an organic substance EMC, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, butadiene-styrene rubber SBR, polyvinyl chloride, polyethylene, polyethylene oxide, polypropylene oxide, polyethylene succinate, polyethylene sebacate, Polyethylene glycol imine, polyacetylene, polyparaphenylene, polyaniline, polypyrrole, polyacene, poly-m-phenylenediamine, polythiophene, poly (p-phenol Vinylene), polythiophene, and a polyacrylonitrile, one or more polyimides and polyphenylene sulfide, they form a pyrolyzed coating materials.

When a resin is used as the precursor of the hard carbon substrate, the mass of the precursor of the coating material is 1 to 15% of the precursor of the hard carbon substrate. The composite hard carbon negative electrode material of the lithium ion battery is an irregular fine particle having a uniform phase distribution and a lump shape, has a porous structure, a pore diameter of 0.2 to 1 OOnm, and a porosity of 9 to 19% ( The ratio of the volume of pores between particles to the total volume in the bulk volume of the granular material), the interlayer distance d ₀₀₂ of the 002 crystal plane d ₀₀₂ value is 0.338 to 0.475 nm, the particle size range is 0.5 to 90 μm, and the specific surface area is 1.9 to 75.3 m ² / g, the true density is 1.53 to 2.35 g / cm ³ , the tap density is 0.88 to 1.43 g / cm ³ , and the carbon element content is 90.5% or more. At 0.2C, the initial reversible capacity is 455.2mAh / g or more, and the initial coulomb efficiency is 79.4% or more.

The precursor of the hard carbon substrate includes 25% by mass to less than 100% by mass of resin (25% by mass ≦ resin <100% by mass) and more than 0% by mass and 75% by mass or less of a curing agent (0% by mass <curing). Agent ≦ 75 mass%) and more than 0 mass% and 15 mass% or less dopant (0 mass% <dopant ≦ 15 mass%). The dopant is composed of a simple metal, a non-metal simple substance, a metal compound, and a non-metal compound. One or more, and the resin and the curing agent are mixed with a dopant after the polymerization reaction and further thermally decomposed to form a hard carbon substrate.

The precursor of the hard carbon substrate includes 25% by mass to less than 100% by mass of resin (25% by mass ≦ resin <100% by mass) and more than 0% by mass and 75% by mass or less of a curing agent (0% by mass <curing). (Hardening agent ≦ 75% by mass), a hardener is added to the resin, and after the polymerization chemical reaction, it is thermally decomposed to form a hard carbon substrate.

The precursor of the hard carbon substrate includes 85% by mass to less than 100% by mass of resin (85% by mass ≦ resin <100% by mass) and more than 0% by mass and 15% by mass or less of dopant (0% by mass <dopant ≦ 15 mass%), and a resin and a metal simple substance, a non-metal simple substance, a metal compound, and one or more dopants in the non-metallic compound are mixed and thermally decomposed to form a hard carbon substrate.

Precursor of the hard carbon substrate is an acrylic resin which is a resin, polyvinyl chloride, and a polycarbonate, epoxy resins, one or more phenolic resins and poly formaldehyde, they thermally decompose to form a hard carbon substrate.

  The curing agent is at least one of hexamethylenediamine, m-phenylenediamine, aniline formaldehyde resin, polyamide resin, phthalic anhydride, and benzenesulfonic acid.

  The simple metal is at least one of copper, lead, antimony, tin, cobalt, and nickel.

  The metal compound is one of tin oxide, cobalt oxide, nickel oxide, sodium phosphate, sodium dihydrogen phosphate, tin acetate, tin chloride, cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide. That's it.

  The non-metal simple substance is at least one of silicon, sulfur and boron.

  The nonmetallic compound is at least one of silicon dioxide, phosphorus pentoxide, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate, ammonium sulfate, silicone resin, and ethylene glycol borate.

The dopant is solid particles or liquid, and has an effect of improving the capacity and initial Coulomb efficiency of the composite hard carbon negative electrode material of the lithium ion battery of the present invention. The said hardening | curing agent is for improving the capacity | capacitance and hard-coulomb efficiency of hard carbon. Since a general-purpose resin , a curing agent, a metal simple substance, a non-metal simple substance, a metal compound or a non-metal compound, and a coating substance are used, the cost of the material of the present invention is low.

When using resin as a precursor of a hard carbon base, the manufacturing method of the composite hard carbon negative electrode material of the lithium ion battery of the present invention includes the following steps.

(1) Step 1: Curing step
Add a solid or liquid curing agent of more than 0% by mass and 75% by mass or less to 25% by mass to less than 100% by mass of granular or liquid resin , stir uniformly, and cure in air at room temperature for 3-50h To obtain a solid precursor.

(2) Step 2: Low-temperature pre-sintering step To improve the yield, capacity and initial coulomb efficiency of hard carbon, and to generate a porous structure, the precursor is SXQ12-14 made by Yixing City Flyer Electric Furnace Co., Ltd. In a -20 type box type resistance furnace, the temperature is raised to 150 ° C. to 400 ° C. at a rate of 0.1 to 1 ° C./min, and the nitrogen gas flow rate is set to 0.18 to 0.4 m ³ / h under the protection of nitrogen gas. Then, low temperature pre-sintering is performed for 2 to 24 hours, and the furnace is naturally cooled to room temperature to obtain a solid honeycomb-like grayish black material.

(3) Process 3: Grinding process Solid honeycomb gray-black substance is pulverized or ball milled to obtain a powder with a particle size of 1-60μm, and the particle size of the material is adjusted using a QM-1SP4 type planetary ball mill manufactured by Nanjing University The size is controlled to be suitable for the dope.

(4) Step 4: A step of doping a metal simple substance, a non-metal simple substance, a metal compound or a non-metallic compound. Add one or more of the metal compounds and mix for 26 to 120 minutes at a rotational speed of 1000 to 3000 r / min using an F-0.4 type high-speed disperser manufactured by Changzhou Wujin Happo Machinery Co., Ltd. to obtain an improved precursor Improve hard carbon capacity and initial coulomb efficiency. Mixing and stirring of simple metal, non-metal simple substance, metal compound or non-metal compound to be doped may be performed at a rotational speed of 2000 to 4500 r / min and time of 10 to 120 min during the curing process. You may go later.

(5) Process 5: Pyrolysis process The improved precursor is placed in a SXQ12-14-20 box type resistance furnace manufactured by Yixing City Feida Electric Furnace Co., Ltd. and 560-1500 ° C at a rate of 0.3-10 ° C / min. Under the protection of nitrogen gas, pyrolysis is performed at a flow rate of nitrogen gas of 0.1 to 0.4 m ³ / h for 0.5 to 7.5 h, and the furnace is naturally cooled to room temperature to produce hard carbon.

(6) Step 6: Grinding Step Hard carbon is ball milled or pulverized to obtain a hard carbon substrate having a particle size of 1 to 60 μm.

(7) Process 7: Coating process VC-150 type mixer manufactured by Wuxi Shinko Powder Processing Process Co., Ltd. by adding the precursor of the coating material to the hard carbon base in an amount of 1 to 15% by mass of the precursor of the hard carbon base. , After mixing for 20-50 min at a rotational speed of 1400-3500r / min, put it in Yxing City Feida Electric Furnace Co., Ltd. SXQ12-14-20 box type resistance furnace and speed at 1-10 ° C / min. The temperature is increased to ˜1500 ° C., and the nitrogen gas flow rate is 0.1 to 0.4 m ³ / h under the protection of the nitrogen gas, and the treatment is performed for 2 to 8 hours to make the surface of the hard carbon material smoother. The specific surface area is reduced, the inside of the furnace is naturally cooled to room temperature, and a sieve of 200 mesh is applied to obtain a composite hard carbon negative electrode material for a lithium ion battery.

When the precursor of the hard carbon substrate is made of a resin and a curing agent, the doping in the step 4 is not performed.

In the case where the precursor of the hard carbon substrate is composed of a resin and a dopant, in Step 1, first, the F-0.4 type high-speed disperser manufactured by Takeshin Happo Machinery Co., Ltd. is used, and both of them are rotated at a rotational speed of 2000-4500 r / min. Mix and stir for ~ 120min and cure in air at room temperature for 3-50h. The dope in step 4 is not performed.

When the precursor of the hard carbon substrate is a resin , in Step 1, it is cured in air at room temperature at 3 to 5 Oh, and the doping in Step 4 is not performed.

  The low-temperature pre-sintering, thermal decomposition, and high-temperature treatment may be performed under the protection of helium gas, argon gas, or xenon gas that is a protective gas.

A composite hard carbon negative electrode material for a lithium-ion battery manufactured using a resin as a precursor of a hard carbon substrate was observed with a KYKY2800B scanning electron microscope manufactured by Beijing China Science and Technology Development Co., Ltd. It is irregular fine particles. Using a measurement area uniformly distributed and measured with a specific surface area measuring device NOVA1000 manufactured by QUANTA CHROME, the pore size distribution is 0.2 to 1 OOnm, and the porosity is 9 to 19 %. The d ₀₀₂ value measured by an X-ray diffractometer PW3040 / 60 X'Pert manufactured by PANalytical BV (Netherlands) is 0.338 to 0.475 nm. The particle size range measured by Mastersizer 2000, a laser particle size distribution meter manufactured by Malvern Instruments, UK, is 0.5 to 90 μm. The specific surface area measured by a fully automatic specific surface area / pore distribution measuring device Tristar 3000 manufactured by Micromeritics, Inc. of the United States is 1.9-75.3 m ² / g. The true density measured by an Ultrapycnometer 1000 type fully automatic true density measuring device manufactured by Quantachrome of the United States is 1.54 to 2.35 g / cm ³ . The tap density measured by Beijing Zhongxi Far University Technology Co., Ltd. FZS4-4 type tap density meter is 0.88 to 1.43 g / cm ³ .

The remaining amount of carbon is measured by placing the sample to be measured in a cleaned crucible and drying it in an oven at 110 ° C ± 5 ° C for 1 h, and a muffle furnace at 950 ° C ± 50 ° C. Baked for 1 hour, cooled in air for 2 minutes, put the porcelain boat in a dryer, cooled for 30 minutes, cooled to room temperature, then weighed to the accuracy of O.OOO1g, and continuous 2 Step 2 is repeated until the difference in weight is 0.0004 g or less. Step 3 with the crucible mass set to m ₁ and about 1 g of the dried sample are weighed and placed in a porcelain boat, and weighed to the accuracy of O.OOO1 g. Step ₂ to set m ₂ and put the porcelain boat containing the sample in a muffle furnace at 950 ° C. ± 50 ° C., fire for 1.5 hours, take out the porcelain boat, cool with air for 2 min, and dry After cooling to room temperature for 30 minutes, cooling to room temperature, weighing to the accuracy of O.OOO1g, 5 and continuous weighing Repeat step 5 until the difference is below 0.0004 g, and a step 6, m _3.

The content of carbon element is calculated by the following formula.
C% = [(m ₂ −m ₃ ) / (m ₂ −m ₁ )] × 100%
(Where m ₁ is the mass of the porcelain boat, m ₂ is the mass of the porcelain boat and the sample, and m ₃ is the mass of the porcelain boat and the ash).
In the hard carbon negative electrode material for a lithium ion battery produced by the method of the present invention, the carbon element content is 90% or more.

N-methylpyrrolidone NMP was prepared by mixing the negative electrode material produced in Examples 1 to 13, polyvinylidene fluoride PVDF as an adhesive, and Super-P as a conductive agent in a mass ratio of 92: 5: 3. Was added as a dispersant to prepare a slurry, uniformly applied to a copper foil with a thickness of 1 Oμm, pressed into a sheet, a circular carbon film having a diameter of 1 cm was produced, and dried in a drying box at 120 ° C. for 12 hours. Prepare for the next use. Using a lithium metal sheet as a counter electrode, an electrolyte solution in which a 1 mol / LLiPF6 ternary mixed solvent is mixed in a volume ratio of EC: DMC: EMC 1: 1: 1 is used, and a polypropylene microporous membrane is used as a separator. A simulated battery (MB200B model manufactured by MBRAUN Glovebox Systems, Germany) is assembled in a glove box filled with argon gas. The simulation battery charge / discharge test is the first reversible at 40C, 30C, 1C, 0.2C with the charge / discharge voltage limited to 0.001-2.0V in the BTS-5V 1OOmA battery test system made by Shenzhen Shinwei Battery Test Equipment Co., Ltd. Measure capacity and initial coulomb efficiency. The formula for calculating the initial coulomb efficiency is
Initial coulomb efficiency = initial charge capacity / initial discharge capacity.

Batteries of Comparative Examples 1 and 2 are manufactured by the above method using artificial graphite as a negative electrode material. Artificial graphite specific surface area of 1Om ² / g, a distance d ₀₀₂ of the crystal layers 0.3358Nm, true density of 2.22 g / cm ^3, a tap density of 1.01 g / cm ^3, the particle size is 1～60Myuemu. The initial reversible capacity and initial Coulomb efficiency are measured by the same method as described above.

  The formulations of Examples 1 to 13 are shown in Table 1, the production processes of Examples 1 to 13 are shown in Table 2, the physical and chemical performance measurement results of Examples 1 to 13 are shown in Table 3, and Examples 1 to 13 are shown. And the measurement result of the electrical performance of Comparative Examples 1-4 is shown in Table 4.

  As shown in FIG. 1, the material manufactured in Example 1 has a lump-like irregular shape, a relatively uniform size, and a microporous structure.

As shown in FIG. 2, d ₀₀₂ is 0.388, and composite hard carbon has a porous and irregular structure, and therefore has an interlayer distance d ₀₀₂ larger than that of a normal graphite material.

  As shown in Fig. 3, 40C / 1C charge capacity retention rate is 95.2% and 30C / 1C charge capacity retention rate is 96.2% under normal conditions at high rates of 40C and 30C. It has excellent high-rate charge / discharge performance because of its microporous, disordered and irregular structure.

  As shown in FIG. 4, the 300 cycle capacity retention at a rate of 60 ° C. and 0.2 C is 96%, and the material produced in Example 1 has excellent high temperature cycle performance.

  As shown in FIG. 5, the 100 cycle capacity retention at a rate of −30 ° C. and 0.2 C is 88%, and the material produced in Example 1 has excellent low temperature cycle performance.

When a plant raw material is used as the precursor of the hard carbon substrate, the mass of the coating material precursor is 1 to 25% of the mass of the precursor of the hard carbon substrate. The coating material is chemisorbed, chemically reacted or physically adsorbed on the surface of the hard carbon substrate, and the surface of the hard carbon substrate is bonded to the coating material by a chemical bond or van der Waals force. Having a pore size of 1.0 to 55 nm and a particle size of 2 to 60 μm. After coating, the pore size decreases as 0.5-50 nm and the particle size increases as 3.5-70 μm. The composite hard carbon negative electrode material of the lithium ion battery has a lump shape and / or flake shape, a particle size of 3.5 to 70 μm, a specific surface area of 7.5 to ²⁰ m ² / g, and a honeycomb-like opening on the material surface. It has a structure with a pore diameter of 0.5 to 50 nm, a porosity of 9 to 16%, an interlayer distance d ₀₀₂ value of 002 crystal plane of 0.337 to 0.455 nm, a true density of 1.55 to 2.25 g / cm ³ , and a tap density of 0.91. ˜1.45 g / cm ³ , and its carbon element content is 94% or more. In the case of 0.2C, the initial reversible capacity is 450 mAh / g or more, and the initial coulomb efficiency is 81.3%.

  The precursor of the hard carbon substrate is at least one of pollen, rice husk, sweet potato stalk, walnut husk, bamboo, sake lees, and wood chips, which are plant materials, and these are thermally decomposed to form a hard carbon substrate.

  The precursor of the hard carbon substrate is a mixture of a plant raw material and a dopant occupying more than 0% by mass and 40% by mass or less of the plant raw material, and these are thermally decomposed to form a hard carbon substrate. The plant material is at least one of pollen, rice husk, sweet potato stalk, walnut husk, bamboo, sake lees and wood chips.

  When a plant raw material is used as the precursor of the hard carbon substrate, the dopant is a metal compound, a nonmetal compound, a metal simple substance, or a nonmetal simple substance. The metal compound is a metal oxide, a metal salt, or a metal alkali. The nonmetallic compound is a nonmetallic oxide, an acid, an organic substance of a nonmetallic element, or a nonmetallic salt.

  The metal oxide is at least one of tin oxide, cobalt oxide, and nickel oxide.

  The metal salt is at least one of sodium phosphate, tin chloride, cobalt carbonate, and sodium dihydrogen phosphate.

  The metal alkali is at least one of copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide.

  The non-metal oxide is silicon dioxide and / or phosphorus pentoxide.

  The acid is at least one of boric acid, silicic acid and phosphoric acid.

  The nonmetallic salt is at least one of ammonium dihydrogen phosphate, ammonium phosphate, and ammonium sulfate.

  The organic substance of the nonmetallic element is a silicone resin and / or an ethylene glycol borate ester.

  The simple metal is at least one of copper, lead, antimony, tin, cobalt, and nickel.

  The non-metal simple substance is at least one of silicon, sulfur and boron.

  When a plant raw material is used as a precursor of a hard carbon substrate, one of the methods for producing a composite hard carbon negative electrode material for a lithium ion battery of the present invention includes the following steps.

(1) Step 1: Removal of precursor impurities and immersion treatment step
Acid or alkali is added to the precursor plant material so that 80 to 300 ml of acid or alkali is added to 100 g of dry plant material per 100 g. Then, after dispersing for 3 to 30 minutes at a rotational speed of 1000 to 3000 r / min, the sample is immersed for 3 to 50 hours.

  As described above, the plant raw material is hydrofluoric acid, boric acid, sulfuric acid, hydrochloric acid, or nitric acid, and the alkali is potassium hydroxide, calcium hydroxide, or sodium hydroxide.

(2) Process 2: Cleaning process SS300 type 3-column type discharge centrifuge manufactured by Zhangjiagang Huaxiang Centrifuge Manufacturing Co., Ltd. with pure water with electrical conductivity of 13μs / cm to make the precursor pH value 5-9 Wash for 8 to 30 minutes at a rotational speed of 800 to 1400 r / min.

(3) Process 3: Moisture removal and drying process Using a DHG-9140 type high temperature test chamber manufactured by Guangzhou Tono Asahi Test Equipment Co., Ltd., it is dried for 10 to 40 hours under the condition of 80 to 140 ° C. and allowed to cool naturally to room temperature.

(4) Process 4: Low-temperature pre-sintering process Yixing City Flyer Electric Furnace is used to improve the yield, capacity and initial coulomb efficiency of hard carbon, and to generate a honeycomb pore structure on the substrate surface. Put into a SXQ12-14-20 type box type resistance furnace manufactured by Co., Ltd., raise the temperature to 200-500 ° C at a rate of O.1-1O ° C / min, and with a vacuum of 0.03 MPa or less, or with protective gas Under a certain helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas, the flow rate is 0.1 to 0.4 m ³ / h, and low temperature pre-sintering is performed for ³ to 20 hours. A honeycomb-like grayish black substance is obtained.

(5) Process 5: Crushing process Solid honeycomb gray-black substance is pulverized or ball milled to obtain a powder with a particle size of 1 to 60 μm, and the particle size of the material using a QM-1SP4 planetary ball mill manufactured by Nanjing University To a size suitable for the dope.

(6) Step 6: Doping step To the powder, a dopant having a proportion of more than 0% by mass to 40% by mass or less is added to the powder, and 1000 ~ Disperse at a rotational speed of 4500 r / min for 20-95 min to obtain an improved precursor, improving the capacity of hard carbon and the initial Coulomb efficiency.

  The dopant is a dopant when a plant raw material is used as the precursor of the hard carbon substrate.

  The dope process may be performed before the low temperature pre-sintering.

(7) Process 7: Pyrolysis process The improved precursor is placed in a SXQ12-14-20 box type resistance furnace manufactured by Yixing City Fida Electric Furnace Co., Ltd., and the temperature is increased from O.1 to 1O ° C / min. The temperature is raised to 500 to 1300 ° C. at a speed of 0.03 MPa or less, or helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas as a protective gas, and the flow rate is set to 0.1 to 0.4 m ³ / h. Pyrolysis of 1 ~ 1Oh, the inside of the furnace is naturally cooled to room temperature, and hard carbon is obtained.

(8) Process 8: Grinding or ball milling process Using a QM-1SP4 type planetary ball mill manufactured by Nanjing University Gigyo Co., Ltd., hard carbon is ball milled or ground to obtain a hard carbon substrate having a particle size of 2 to 65 μm.

(9) Process 9: Coating process VC-150 type mixer manufactured by Wuxi Shinko Powder Processing Process Co., Ltd. by adding a precursor of the coating material to the hard carbon base in an amount of 1 to 25% by mass of the precursor of the hard carbon base. After mixing for 2 to 40 min at a rotational speed of 1000 to 4500 r / min, put it in a SXQ12-14-20 box type resistance furnace made by Yixing Feida Electric Furnace Co., Ltd. The temperature is raised to 400-1300 ° C. at a rate of min, and the flow rate is 0.1-0.4 m ³ at a vacuum of 0.03 MPa or less, or under a protective gas such as helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas. / H, pyrolysis treatment for 1 to 24 hours, allowing the furnace to cool naturally to room temperature, smoothing the surface of the hard carbon material to reduce the specific surface area of the final product, passing through a 200 mesh sieve and having a particle size of 3.5 to 70 μm A composite hard carbon negative electrode material for a lithium ion battery is obtained.

  The precursor of the coating material is the organic material.

  When a plant raw material is used as the precursor of the hard carbon substrate, Method 2 for producing a composite hard carbon negative electrode material for a lithium ion battery of the present invention includes the following steps.

(1) Step 1: pulverization step The plant material is mechanically pulverized or jet milled with a general-purpose mechanical pulverizer or jet mill to obtain a powder substance having a particle size of 40 to 1OOμm.

(2) Process 2: Impurity removal / immersion process
Add hydrofluoric acid, boric acid, sulfuric acid, hydrochloric acid, nitric acid, potassium hydroxide, calcium hydroxide or sodium hydroxide to the powdered material so that 80-300 ml of acid or alkali is added to 100 g of dry plant raw material per 100 g. Using a F-0.4 type high-speed disperser manufactured by Changshu Takejin Happo Machinery Co., Ltd., disperse for 3 to 30 minutes at a rotational speed of 1000 to 3 OOOr / min, and then immersed for 3 to 50 hours.

(3) Process 3: Cleaning process SS300 type 3-column discharge centrifuge made by Zhangjiagang Huaxiang Centrifuge Manufacturing Co., Ltd. with pure water with conductivity of 13μm / cm to control the pH of the precursor to 5-9 Use a machine to clean for 8 to 30 minutes at a rotational speed of 800 to 1400 r / min.

(4) Process 4: Moisture removal / drying process Using a DHG-9140 type high temperature test chamber made by Guangzhou Tono Asahi Test Equipment Co., Ltd., drying at 80-140 ° C for 10-40h and letting it naturally cool to room temperature .

(5) Process 5: Doping process Add a dopant that is greater than 0% by weight and less than 40% by weight in the dried material, and add 1000 to 4500r in a VC-150 mixer manufactured by Wuxi Shinko Powder Processing Process Co., Ltd. Mix for 20 to 95 minutes at a rotation speed of / min.

  The said dopant is a dopant in case a plant raw material is used as a precursor of the said hard carbon base | substrate.

(6) Step 6: Low-temperature pre-sintering step The doped precursor is put into a SXQ12-14-20 type box type resistance furnace made by Yixing City Feida Electric Furnace Co., Ltd., and O.1-1O ° C / min. The temperature is raised to 200 to 500 ° C. at a rate of 0.1 to 0.4 m ³ / h at a vacuum level of 0.03 MPa or less or under a protective gas such as helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas. Then, 3 ~ 2Oh low temperature pre-sintering is performed, and the inside of the furnace is naturally cooled to room temperature.

(7) Step 7: Grinding or ball milling step A hard carbon precursor having a particle size of 1 to 65 μm is obtained using a QM-1SP4 planetary ball mill manufactured by Nanjing University Gikijo.

(8) Process 8: Pyrolysis process The precursor of hard carbon is put in a SXQ12-14-20 box type resistance furnace manufactured by Yixing City Fida Electric Furnace Co., Ltd. and a rate of O.1 to 1O ° C / min is 500. Pyrolysis with a flow rate of 0.1 to 0.4 m ³ / h at a vacuum of 0.03 MPa or less or under a protective gas such as helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas. 1 to 1Oh, a hard carbon substrate is obtained, and the furnace is naturally cooled to room temperature to obtain hard carbon.

(9) Step 9: Step of obtaining a hard carbon substrate Hard carbon is ball milled or pulverized for 10 to 30 minutes to obtain a hard carbon substrate having a particle size of 2 to 60 μm.

(10) Process 10: Coating process VC-150 type mixer manufactured by Wuxi Shinko Powder Processing Process Co., Ltd. by adding a precursor of the coating material to the hard carbon base in an amount of 1 to 25% by mass of the precursor of the hard carbon base. After mixing for 2 to 40 min at a rotational speed of 1000 to 4500 r / min, put it in a SXQ12-14-20 box type resistance furnace made by Yixing Feida Electric Furnace Co., Ltd. The temperature is raised to 400-1300 ° C. at a rate of min, and the flow rate is 0.1-0.4 m ³ at a vacuum of 0.03 MPa or less, or under a protective gas such as helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas. / H, pyrolysis treatment for 1 to 24 hours, allowing the furnace to cool naturally to room temperature, smoothing the surface of the hard carbon material to reduce the specific surface area of the final product, passing through a 200 mesh sieve and having a particle size of 3.5 to 70 μm A composite hard carbon negative electrode material for a lithium ion battery is obtained.

  The precursor of the coating material is the organic material.

  When a plant raw material is used as the precursor of the hard carbon substrate, method 3 for producing a composite hard carbon negative electrode material for a lithium ion battery of the present invention includes the following steps.

(1) Step 1: Grinding step Using at least one kind of pollen, rice husk, sweet potato stalk, walnut husk, bamboo, sake lees, and wood chips that are precursor plant raw materials, using a general-purpose mechanical pulverizer or jet mill Mechanically pulverized or jet milled to obtain a powder material having a particle size of 40 to 1OO μm.

(2) Process 2: Impurity removal / immersion process
Add hydrofluoric acid, boric acid, sulfuric acid, hydrochloric acid, nitric acid, potassium hydroxide, calcium hydroxide or sodium hydroxide to the powdered material so that 80 to 300 ml of acid or alkali is added to dry plant raw material per 100 g, Disperse for 3 to 30 min at 1000 to 300 Or / min using an F-0.4 type high-speed disperser manufactured by Changzhou Wujin Happo Machinery Co.

(3) Process 3: Cleaning process SS300 type 3-column discharge centrifuge made by Zhangjiagang Huaxiang Centrifuge Manufacturing Co., Ltd. with pure water with conductivity of 13μs / cm to control the pH of the precursor to 5-9 Use a machine to clean for 8 to 30 minutes at a rotational speed of 800 to 1400 r / min.

(4) Process 4: Moisture removal and drying process Using a DHG-9140 type high-temperature test chamber manufactured by Guangzhou Tono Asahi Test Equipment Co., Ltd., it is dried for 10 to 40 hours under conditions of 80 to 140 ° C and allowed to cool naturally to room temperature. .

(5) Process 5: Low-temperature pre-sintering process The dried precursor is placed in a resistance furnace of SXQ12-14-20 type box type made by Yixing City Feida Electric Co., Ltd. The temperature is raised to 200 to 500 ° C. at a rate of 0.1 to 0.4 m ³ / h at a vacuum level of 0.03 MPa or less or under a protective gas such as helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas. Then, low temperature pre-sintering is performed for 3 to 20 hours, and the inside of the furnace is naturally cooled to room temperature.

(6) Step 6: Grinding Step Using a QM-1SP4 planetary ball mill manufactured by Nanjing University Gikijo, the pre-sintered material is crushed or ball milled to obtain a powder having a particle size of 1 to 60 μm.

(7) Step 7: Doping step Add a dopant of more than 0% by mass and less than 40% by mass in the pre-sintered material, and add 1000 to 100% in a VC-150 type mixer manufactured by Wuxi Shinko Powder Processing Process Co., Ltd. Mix for 20 to 95 min at a rotational speed of 4500 r / min.

  The dopant is a dopant when a plant raw material is used as the precursor of the hard carbon substrate.

(8) Process 8: Pyrolysis process The doped hard carbon precursor is placed in a resistance furnace of SXQ12-14-20 box type made by Yixing City Feida Electric Furnace Co., Ltd. The temperature is raised to 500-1300 ° C. at a rate of 0.03 MPa or less, or under a protective gas of helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas, the flow rate is 0.1-0.4 m ³ / Thermal decomposition is carried out as 1 to 1Oh for h to obtain a hard carbon substrate, and the furnace is naturally cooled to room temperature to obtain hard carbon.

(9) Process 9: Grinding or ball milling process Using a QM-1SP4 planetary ball mill manufactured by Nanjing University Gikijo, the hard carbon is ball milled or ground for 20 to 90 minutes to obtain a hard carbon substrate having a particle size of 2 to 60 μm.

(10) Process 10: Coating process VC-150 type mixer manufactured by Wuxi Shinko Powder Processing Process Co., Ltd. by adding a precursor of the coating material to the hard carbon base in an amount of 1 to 25% by mass of the precursor of the hard carbon base. After mixing for 2 to 40 min at a rotational speed of 1000 to 4500 r / min, put it in a SXQ12-14-20 box type resistance furnace made by Yixing Feida Electric Furnace Co., Ltd. The temperature is raised to 400-1300 ° C. at a rate of min, and the flow rate is 0.1-0.4 m ³ at a vacuum of 0.03 MPa or less, or under a protective gas such as helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas. / H, pyrolysis treatment for 1-24h, naturally cool the inside of the furnace to room temperature, smooth the surface of the hard carbon material and reduce the specific surface area of the final product, passing through a 200 mesh sieve, the particle size of 3.5-70μm A composite hard carbon negative electrode material for a lithium ion battery is obtained.

  The precursor of the coating material is the organic material.

  When a plant raw material is used as the precursor of the hard carbon substrate, 4 of the method for producing a composite hard carbon negative electrode material for a lithium ion battery of the present invention includes the following steps.

(1) Step 1: Grinding step Use at least one kind of pollen, rice husk, sweet potato stalk, walnut husk, bamboo, sake lees, and wood chips that are precursor plant raw materials, using a general-purpose mechanical crusher or jet mill. Then, it is mechanically pulverized or jet milled to obtain a powder having a particle size of 40 to 1OO μm.

(2) Process 2: Impurity removal / immersion process
Add hydrofluoric acid, boric acid, sulfuric acid, hydrochloric acid, nitric acid, potassium hydroxide, calcium hydroxide or sodium hydroxide to the powder so that 80-300 ml of acid or alkali is added to 100 g of dry plant material per 100 g. Disperse for 3 to 30 minutes at a rotational speed of 1000 to 3000 r / min using a F-0.4 type high-speed disperser manufactured by Wujin Happo Machinery, and then immerse for 3 to 50 hours.

(3) Process 3: Cleaning process SS300 type 3-column discharge centrifuge made by Zhangjiagang Huaxiang Centrifuge Manufacturing Co., Ltd. with pure water with conductivity of 13μS / cm to control the pH of the precursor to 5-9 Use a machine to clean for 8 to 30 minutes at a rotational speed of 800 to 1400 r / min.

(4) Process 4: Moisture removal / drying process Using a DHG-9140 type drying box made by Guangzhou Tono Asahi Test Equipment Co., Ltd., it is dried at 80-140 ° C for 10-40h and allowed to cool to room temperature. .

(5) Process 5: Low-temperature pre-sintering process The dried precursor is put into a SXQ12-14-20 type box type resistance furnace manufactured by Yixing City Fida Electric Furnace Co., Ltd., and O.1 to 1O ° C / min. The temperature is raised to 200 to 500 ° C. at a rate of 0.03 MPa or less, or under a protective gas of helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas, the flow rate is 0.1 to 0.4 m ³ / h, low temperature pre-sintering is performed for 3 to 20 hours, and the inside of the furnace is naturally cooled to room temperature.

(6) Step 6: Grinding step Using a QM-1SP4 type planetary ball mill manufactured by Nanjing University Gikijo, the pre-sintered material is pulverized or ball milled to obtain a powder having a particle size of 1 to 60 μm.

(7) Process 7: Pyrolysis process The hard carbon precursor is put into a SXQ12-14-20 box type resistance furnace manufactured by Yixing City Fida Electric Furnace Co., Ltd., at a rate of O.1 to 1O ° C / min. Heat to 500-1300 ° C and heat at a vacuum of 0.03 MPa or less or under protective gas helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas at a flow rate of 0.1-0.4 m ³ / h Decomposition is performed for 1 to 1Oh to obtain a hard carbon substrate, and the furnace is naturally cooled to room temperature to obtain hard carbon.

(8) Process 8: Grinding or ball milling process Using a QM-1SP4 type star ball mill manufactured by Nanjing University Gikijo, the hard carbon is ball milled or ground for 20 to 90 minutes to obtain a hard carbon substrate having a particle size of 2 to 60 μm.

(9) Process 9: Coating process VC-150 type mixer manufactured by Wuxi Shinko Powder Processing Process Co., Ltd. by adding a precursor of the coating material to the hard carbon base in an amount of 1 to 25% by mass of the precursor of the hard carbon base. After mixing for 2 to 40 min at a rotational speed of 1000 to 4500 r / min, put it in a SXQ12-14-20 box type resistance furnace made by Yixing Feida Electric Furnace Co., Ltd. The temperature is raised to 400-1300 ° C. at a rate of min, and the flow rate is 0.1-0.4 m ³ at a vacuum of 0.03 MPa or less, or under a protective gas such as helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas. / H is subjected to a pyrolysis treatment for 1 to 24 hours, and the furnace is naturally cooled to room temperature and passed through a 200 mesh sieve to obtain a composite hard carbon negative electrode material for a lithium ion battery having a particle size of 3.5 to 70 μm.

  The precursor of the coating material is the organic material.

The composite hard carbon negative electrode material of a lithium ion battery manufactured using a plant raw material as a precursor of a hard carbon substrate is measured by the above-mentioned instrument, and the shape thereof is a lump and / or flake-like particle, and the surface of the honeycomb is open on the surface. has a pore structure, pore size distribution 0.5 to 50 nm, a porosity of 9 to 16%, d ₀₀₂ value 0.337～0.455Nm, size range is 3.5～70Myuemu, specific surface area of 0.5 to 20 m ² / g, a true density Is 1.55 to 2.25 g / cm ³ , and the tap density is 0.91 to 1.45 g / cm ³ . The surface of the hard carbon substrate and the coating material are bonded by chemical bonds or van der Waals forces, and according to theoretical analysis, van der Waals forces are intermolecular forces derived from orientation, induced and dispersion forces, and for many molecules Dispersion is the main force. The acting force of the hard carbon substrate surface and the coating material is formed during the coating process.

As described above, the method for measuring the remaining amount of carbon calculates the carbon element content.
C% = [(m ₂ −m ₃ ) / (m ₂ −m ₁ )] × 100%
Carbon element content is 94% or more.

  The formulations of Examples 14 to 21 are shown in Table 5, the manufacturing process is shown in Table 6, the physical and chemical performance measurement results are shown in Table 7, a simulated battery was manufactured by the above method, and the electrical performance measurement results. Is shown in Table 8.

  As shown in FIG. 6, the shape is massive and / or flaky particles, and has a honeycomb-like pore structure on the material surface. The pore diameter is 0.5 to 40 nm and the porosity is 12%.

As shown in FIG. 7, since d ₀₀₂ is 0.385 nm and the composite hard carbon has a porous structure, the interlayer distance d ₀₀₂ is larger than that of ordinary graphite materials.

  As shown in Fig. 8, 40C / 1C charge capacity retention rate reached 95.3% and 30C / 1C charge capacity retention rate reached 96.9% under conditions of high rates of 40C and 30C at room temperature. Due to the pore and disordered irregular structure, it has excellent high rate charge / discharge performance.

  As shown in FIG. 9, the 300 cycle capacity retention at 60 ° C. and 0.2 C rate is 97.4%, and the manufactured material has excellent high temperature cycle performance.

  As shown in FIG. 10, the 100 cycle capacity retention at -30 ° C. and 0.2 C rate is 88.2%, and the manufactured material has excellent low temperature cycle performance.

(Comparative Example 3)
A battery of a comparative example is manufactured by the above method using natural graphite as a negative electrode material. Natural graphite has a specific surface area of 8.3 m ² / g, a crystal interlayer distance d ₀₀₂ of 0.3365 nm, a true density of 2.22 g / cm ³ , a tap density of 1.05 g / cm ³ , and a particle size of 1 to 60 μm. The initial reversible capacity and initial Coulomb efficiency were measured by the same method as described above, and the measurement results of electrical performance are shown in Table 8.

(Comparative Example 4)
A battery of a comparative example is manufactured by the above method using natural graphite as a negative electrode material. Natural graphite specific surface area of 6.3 m ² / g, crystal interlayer distance d ₀₀₂ is 0.3358Nm, true density of 2.23 g / cm ^3, a tap density of 1.14 g / cm ^3, the particle size is 1.1～58Myuemu. The initial reversible capacity and initial Coulomb efficiency were measured by the same method as described above, and the measurement results of electrical performance are shown in Table 8.

  Table 1 Formulations of Examples 1-13

  Table 2 Manufacturing process of Examples 1-13

  Table 3 Examples 1-13 Physical and chemical performance measurements

  Table 4 Measurement results of electrical performance of Examples 1 to 13 and Comparative Examples 1 and 2

  Table 5 Formulations of Examples 14-21

  Table 6 Manufacturing process of Examples 14-21

  Table 7 Physical and chemical performance measurement results of Examples 14-21

  Table 8 Measurement results of electrical performance of Examples 14 to 21 and Comparative Examples 3 to 4

Claims (12)

A composite hard carbon negative electrode material for a lithium ion battery, the surface of the hard carbon substrate of the composite hard carbon negative electrode material for the lithium ion battery is coated with a coating substance ,
Precursor before Symbol coating material, an epoxy resin an organic substance, pitch, ethyl methyl carbonate, Po polystyrene, Po Rifu' fluoride, polypropylene oxide, polyethylene succinate, polyethylene sebacate, Po Li acetylene, poly para phenylene, and a port Ripiroru, Po Li thiophene and poly (p- phenylene vinylene) one or more, to form a coating material which is thermally decomposed,
The precursor of the hard carbon substrate is at least one of acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, phenol resin and polyformaldehyde, which is a resin, or the precursor of the hard carbon substrate is 25% by mass to The resin comprises less than 100% by mass of the resin and a curing agent of greater than 0% by mass and 75% by mass or less, or the precursor of the hard carbon substrate comprises 25% by mass to less than 100% by mass of the resin and 0% by mass More than 75% by mass of a curing agent and more than 0% by mass and 15% by mass or less of a dopant, or the precursor of the hard carbon substrate is 85% by mass to less than 100% by mass of the resin and 0% by mass % And 15% by mass or less of dopants, which are pyrolyzed to form a hard carbon substrate,
The mass of the precursor of the coating material is 1-15% of the mass of the precursor of the hard carbon substrate;
The composite hard carbon negative electrode material of the lithium ion battery is a fine particle having a lump shape, has a porous structure, has a pore diameter of 0.2 to 1 OOnm, a porosity of 9 to 19%, and an interlayer distance of 002 crystal plane of 0.338. 0.475 nm, particle size range 0.5 to 90 μm, specific surface area 1.9 to 75.3 m ² / g, true density 1.54 to 2.35 g / cm ³ , tap density 0.88 to 1.43 g / cm ³ , The content is 90.5% or more,
The curing agent is one or more of hexamethylenediamine, m-phenylenediamine, aniline formaldehyde resin, polyamide resin, polyformaldehyde, phthalic anhydride, and benzenesulfonic acid;
The dopant is at least one of a simple metal, a metal compound, and a non-metallic compound, the simple metal is tin, and the metal compound is at least one of sodium phosphate, tin chloride, and tin hydroxide, A composite hard carbon negative electrode material for a lithium ion battery, wherein the metal compound is at least one of phosphorus pentoxide, boric acid, ammonium phosphate, and silicone resin . A composite hard carbon negative electrode material for a lithium ion battery, the surface of the hard carbon substrate of the composite hard carbon negative electrode material for the lithium ion battery is coated with a coating substance ,
Precursor before Symbol coating material, epoxy resin is an organic material, a phenolic resin, and carboxymethylcellulose, pitch, Po polyvinyl alcohol, Po Li acetylene, Po Ripiroru and polyimide 1 or more, and they are thermally decomposed Forming a coating material ,
The precursor of the hard carbon substrate is at least one of pollen, rice husk, sweet potato stalk, walnut husk, bamboo, sake lees, and wood chips, which are plant materials, or the precursor of the hard carbon substrate is the plant material and plant Dopants occupying more than 0% and less than 40% of the raw material are mixed, they are pyrolyzed to form a hard carbon substrate,
The mass of the precursor of the coating material is 1-25% of the mass of the precursor of the hard carbon substrate,
The surface of the hard carbon substrate and the coating material are bonded by chemical bonding or van der Waals force,
The hard carbon substrate has a particle size of 2 to 60 μm, a honeycomb pore structure on the surface, and a pore diameter of 1.0 to 55 nm.
The composite hard carbon negative electrode material of the lithium ion battery is a particle having a lump shape and / or flake shape, a particle size of 3.5 to 70 μm, a specific surface area of 7.5 to ²⁰ m ² / g, It has a honeycomb-like pore structure, pore diameter is 0.2-60 nm, porosity is 9-16%, d ₀₀₂ value which is the distance between layers of 002 crystal plane is 0.337-0.455 nm, true density is 1.55-2.25 g / cm ³ , the tap density is 0.91 to 1.45 g / cm ³ , the carbon element content is 94% or more,
The dopant may be one or more of tin chloride and cobalt carbonate which are metal salts, boric acid which is a nonmetal oxide, ammonium phosphate which is a nonmetal salt, silicon which is a nonmetal simple substance, or a nonmetal compound. A composite hard carbon negative electrode material for a lithium ion battery, which is a silicone resin . A step 1 of curing a resin in air at room temperature for 3 to 50 hours to obtain a solid precursor;
Nitrogen gas flow rate is 0.1-0.4m ³ / h, the precursor is heated to 150 ° C-450 ° C at a rate of 0.1-3 ° C / min, pre-sintered at low temperature for 2-24h, and naturally cooled to room temperature And pulverizing to obtain a powder having a particle size of 1 to 60 μm,
The flow rate of nitrogen gas is 0.1 to 0.4 m ³ / min, the temperature is raised to 560 to 1500 ° C. at a rate of 0.3 to 10 ° C./min, pyrolyzed for 0.5 to 7.5 hours, and the temperature is naturally lowered to room temperature to obtain hard carbon. Step 3 and
Step 4 of hard carbon ball milling or grinding to obtain a hard carbon substrate having a particle size of 1 to 60 μm;
A precursor of the coating material is added to the hard carbon substrate in an amount of 1 to 15% by mass of the precursor of the hard carbon substrate and mixed at a rotational speed of 1400 to 3500 r / min for 20 to 50 minutes. -0.4m ³ / min, the temperature is raised to 500-1500 ° C at a rate of 1-7.5 ° C / min, the coating material is thermally decomposed for 2-8h, and the temperature is naturally lowered to room temperature. And obtaining a carbon negative electrode material 5,
The resin is one or more of acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, phenol resin and polyformaldehyde, and the precursor of the coating material is an organic substance, epoxy resin, phenol resin, carboxymethyl cellulose, pitch, ethyl methyl Carbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, butadiene-styrene rubber, polyvinyl chloride, polyethylene, polyethylene oxide, polypropane oxide, polyethylene succinate, polyethylene sebacate, Polyethylene glycol imine, polyacetylene, polyparaphenylene, polyaniline, polypyrrole, polyacene, poly-m-phenylenedia Emissions, polythiophene, poly (p- phenylene vinylene), polythiophene, polyacrylonitrile method of producing a composite hard carbon negative electrode material of lithium ion batteries, characterized in that it is a polyimide and polyphenylenesulfide 1 or more. As the curing, a curing agent of more than 0% by mass to 75% by mass or less is added to a resin of 25% by mass to less than 100% by mass and stirred uniformly, and cured in air at room temperature for 3 to 50 hours to obtain a solid precursor. The lithium ion according to claim 3 , wherein the curing agent is at least one of hexamethylenediamine, m-phenylenediamine, aniline formaldehyde resin, polyamide resin, phthalic anhydride and benzenesulfonic acid. A method for producing a composite hard carbon negative electrode material for a battery. Following the low-temperature pre-sintering and pulverization, a dopant is added to the powder at a rate of more than 0% by mass and 15% by mass or less, and mixed and stirred at a rotational speed of 1000 to 3000 r / min for 26 to 120 min. One or more of simple substance, non-metal simple substance, metal compound and non-metal compound, the metal simple substance is one or more of copper, lead, antimony, tin, cobalt and nickel, and the metal compound is tin oxide and cobalt oxide. One or more of nickel oxide, sodium phosphate, sodium dihydrogen phosphate, tin acetate, tin chloride, cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, One or more of silicon, sulfur and boron, and the nonmetallic compound is silicon dioxide, phosphorus pentoxide, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate, Ammonium method of producing a composite hard carbon negative electrode material of a lithium ion battery according to claim 3, characterized in that at least one silicone resin and ethylene glycol borate ester. As the curing, a curing agent of more than 0% by mass to 75% by mass and a dopant of more than 0% by mass to 15% by mass are added to a resin of 25% by mass to less than 100% by mass, and 2000 to 4500 r / min. The mixture is stirred for 10 to 120 minutes at a rotational speed of, cured in air at room temperature for 3 to 50 hours to obtain a precursor, and the dopant is one or more of a simple metal, a non-metal simple substance, a metal compound, and a non-metal compound, The simple metal is at least one of copper, lead, antimony, tin, cobalt and nickel, and the metal compound is tin oxide, cobalt oxide, nickel oxide, sodium phosphate, sodium dihydrogen phosphate, tin acetate, tin chloride , Cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, the non-metal simple substance is one or more of silicon, sulfur and boron, and the non-metal compound is silicon dioxide , Pentaacid Phosphoric, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate, ammonium sulfate, lithium ions according to claim 3, characterized in that at least one silicone resin and ethylene glycol borate ester A method for producing a composite hard carbon negative electrode material for a battery. After the low-temperature pre-sintering, a dopant is added at a ratio of more than 0% by mass and 15% by mass or less, and mixed and stirred at a rotational speed of 1000 to 3000 r / min for 26 to 120 minutes. It is one or more of a metal compound and a non-metal compound, the metal simple substance is one or more of copper, lead, antimony, tin, cobalt and nickel, and the metal compound is tin oxide, cobalt oxide, nickel oxide, phosphoric acid It is one or more of sodium, sodium dihydrogen phosphate, tin acetate, tin chloride, cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, and the non-metal element is composed of silicon, sulfur and boron. One or more, and the non-metallic compound is silicon dioxide, phosphorus pentoxide, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate, ammonium sulfate, The method of producing a composite hard carbon negative electrode material of a lithium ion battery according to claim 3, characterized in that recone resin and one or more ethylene glycol borate ester. 85% by mass to less than 100% by mass of resin and more than 0% by mass and 15% by mass or less of dopant are mixed and stirred at a rotational speed of 2000 to 4500 r / min for 10 to 120 min, and cured in air at room temperature for 1 to 6 hours. Step 1 to obtain a solid precursor,
Nitrogen gas flow rate is 0.1-0.4m ³ / h, the precursor is heated to 150 ° C-450 ° C at a rate of 0.1-7 ° C / min, pre-sintered at low temperature for 3-24h, and naturally cooled to room temperature Step 2
The flow rate of nitrogen gas is 0.1-0.4m ³ / h, the temperature is raised to 560-1500 ° C at a rate of 0.3-10 ° C / min, pyrolyzed for 0.5-7.5h, and naturally cooled to room temperature to obtain hard carbon. Step 3 and
Step 4 of ball-milling or pulverizing the hard carbon to obtain a hard carbon substrate having a particle size of 1 to 60 μm;
After the precursor of the coating material is added to the hard carbon substrate in an amount of 1 to 15% of the precursor of the hard carbon substrate and mixed at a rotational speed of 1400 to 35 Or / min for 20 to 50 minutes, the nitrogen gas flow rate is set to 0.1 to 0.4 m ³ / h, the temperature is raised to 500-1500 ° C. at a rate of 1-7.5 ° C./min, the coating is pyrolyzed for 2-8 h, the temperature is naturally lowered to room temperature, and the composite hard carbon of the lithium ion battery And obtaining a negative electrode material 5
The resin is at least one of acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, phenolic resin and polyformaldehyde, and the dopant is at least one of a metal simple substance, a non-metal simple substance, a metal compound and a non-metal compound, The simple metal is at least one of copper, lead, antimony, tin, cobalt and nickel, and the metal compound is tin oxide, cobalt oxide, nickel oxide, sodium phosphate, sodium dihydrogen phosphate, tin acetate, tin chloride , Cobalt carbonate, copper hydroxide, cobalt hydroxide, tin hydroxide and nickel hydroxide, the non-metal simple substance is one or more of silicon, sulfur and boron, and the non-metal compound is silicon dioxide , Phosphorus pentoxide, boric acid, silicic acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium phosphate, sulfuric acid Epoxy resin, phenol resin, carboxymethyl cellulose, pitch, ethyl methyl carbonate, polyvinyl alcohol, polystyrene, polymethacrylic acid, which is one or more of monium, silicone resin and ethylene glycol borate ester, and the precursor of the coating material is organic Methyl, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, butadiene-styrene rubber, polyvinyl chloride, polyethylene, polyethylene oxide, polypropylene oxide, polyethylene succinate, polyethylene sebacate, polyethylene glycol imine, polyacetylene, polyparaphenylene, polyaniline , Polypyrrole, polyacene, poly-m-phenylenediamine, polythiophene, poly (p-phenylene vinylene) Polythiophene, polyacrylonitrile method of producing a composite hard carbon negative electrode material of lithium ion batteries, characterized in that it is a polyimide and polyphenylenesulfide 1 or more. 80 to 300 ml of acid or alkali is added to 100 g of dried plant material per 100 g, soaked for 3 to 50 hours, and the plant material is at least one of pollen, rice husk, sweet potato stalk, walnut shell, bamboo, sake lees, and wood chips, Step 1 wherein the acid is hydrofluoric acid, boric acid, sulfuric acid, hydrochloric acid or nitric acid and the alkali is potassium hydroxide, calcium hydroxide or sodium hydroxide;
Cleaning process 2 using pure water and cleaning for 8 to 30 minutes at a rotational speed of 800 to 1400 r / min;
Step 3 of removing moisture, drying for 10 to 40 hours under conditions of 80 to 140 ° C., and allowing the temperature to fall naturally to room temperature;
Perform low-temperature pre-sintering at a vacuum level of 0.03 MPa or less or under a protective gas of helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas, with a flow rate of 0.1 to 0.4 m ³ / h, O.1 to Step 4 in which the temperature is raised to 200 to 500 ° C. at a rate of 1 ° C./min, pre-sintered at a low temperature for 3 to 20 hours, and the inside of the furnace is naturally cooled to room temperature,
Step 5 for pulverizing to obtain a powder having a particle size of 1 to 60 μm;
O.1-1O ° C / min at a vacuum of 0.03 MPa or less or under a protective gas of helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas, with a flow rate of 0.1-0.4 m ³ / h Step 6 of raising the temperature to 500 to 1300 ° C. at a rate, pyrolyzing 1 to 1 Oh, and naturally lowering the temperature of the furnace to room temperature;
Step 7 for obtaining a hard carbon substrate having a particle size of 2 to 65 μm by grinding or ball mill;
The coating material precursor is added to the hard carbon substrate in an amount of 1 to 25% by mass of the precursor of the hard carbon substrate, mixed at a rotational speed of 1000 to 4500 r / min for 2 to 40 minutes, and then at a vacuum of 0.03 MPa or less. Or under a protective gas of helium gas, nitrogen gas, argon gas, xenon gas or nitrogen gas, the flow rate is 0.1 to 0.4 m ³ / h, and the flow rate is 400 to 1300 ° C. at a rate of O.1 to 1 O ° C./min. The temperature is raised, pyrolysis treatment is performed for 1 to 24 hours, the temperature in the furnace is naturally lowered to room temperature, an epoxy resin, a phenol resin, carboxymethyl cellulose, pitch, ethyl methyl carbonate, polyvinyl alcohol, where the precursor of the coating material is an organic substance, Polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, butadiene-styrene rubber, polyvinyl chloride, polyethylene, polyethylene Lene oxide, polypropylene oxide, polyethylene succinate, polyethylene sebacate, polyethylene glycol imine, polyacetylene, polyparaphenylene, polyaniline, polypyrrole, polyacene, poly-m-phenylenediamine, polythiophene, poly (p-phenylene vinylene), polythiophene, polyacrylonitrile Step 8 which is one or more of polyimide and polyphenylene sulfide;
And a step 9 of obtaining a composite hard carbon negative electrode material for a lithium ion battery having a particle size of 3.5 to 70 μm through a 200-mesh sieve, and a method for producing a composite hard carbon negative electrode material for a lithium ion battery. 80-300 ml of acid or alkali is added to 100 g of dry plant raw material, and before immersing for 3-50 h, the dry plant raw material as a precursor is mechanically pulverized or jet milled to obtain a powder with a particle size of 40-1 OO μm, Following the low-temperature pre-sintering pulverization, a dopant with a proportion of powder exceeding 0% by mass to 40% by mass or less is added and mixed and stirred at a rotational speed of 1000 to 4500 r / min for 20 to 95 min. One or more of tin oxide, cobalt oxide and nickel oxide, or one or more of metal salts such as sodium phosphate, tin chloride, cobalt carbonate and sodium dihydrogen phosphate, copper hydroxide which is a metal alkali, water One or more of cobalt oxide, tin hydroxide and nickel hydroxide, non-metal oxide silicon dioxide and / or phosphorus pentoxide, or one or more of boric acid, silicic acid and phosphoric acid, or non-metallic salt Some phosphoric acid One or more of ammonium hydrogen, ammonium phosphate, and ammonium sulfate, or one or more of silicone resin and / or ethylene glycol borate, or metals such as copper, lead, antimony, tin, cobalt, and nickel, or The method for producing a composite hard carbon negative electrode material for a lithium ion battery according to claim 9 , wherein the material is one or more of silicon, sulfur, and boron, which are non-metal simple substances. As described above, 80 to 300 ml of acid or alkali is added to 100 g of dried plant raw material, and after 3 to 30 minutes of mixing and stirring at a rotational speed of 1000 to 3000 r / min, the mixture is immersed for 3 to 50 hours, and the low temperature pre-sintered pulverization Followed by adding a dopant with a proportion in the powder exceeding 0% by mass and 40% by mass or less, mixing and stirring for 20 to 95 min at a rotational speed of 1000 to 4500 r / min, and the dopant is a metal oxide tin oxide, oxidation One or more of cobalt and nickel oxide, or one or more of metal salts such as sodium phosphate, tin chloride, cobalt carbonate and sodium dihydrogen phosphate, or metal alkali such as copper hydroxide, cobalt hydroxide, tin hydroxide And one or more of nickel hydroxide, non-metal oxide silicon dioxide and / or phosphorus pentoxide, or one or more of boric acid, silicic acid and phosphoric acid, or non-metal salt ammonium dihydrogen phosphate , Phosphoric acid One or more of ammonium and ammonium sulfate, or a silicone resin and / or ethylene glycol borate, or one or more of copper, lead, antimony, tin, cobalt, and nickel, or a non-metal simple substance The method for producing a composite hard carbon negative electrode material for a lithium ion battery according to claim 9 , wherein the material is one or more of silicon, sulfur, and boron. As described above, 80 to 300 ml of acid or alkali is added to 100 g of dry plant raw material, and before immersing for 3 to 50 hours, the dry plant raw material as a precursor is mechanically pulverized or jet milled to obtain a powder with a particle size of 40 to 1 OO μm. Before the low-temperature pre-sintering, a dopant having a proportion of more than 0% by mass and not more than 40% by mass is added and mixed and stirred at a rotational speed of 1000 to 4500 r / min for 20 to 95 min. One or more oxides of tin oxide, cobalt oxide and nickel oxide, or metal salts of sodium phosphate, tin chloride, cobalt carbonate and sodium dihydrogen phosphate, or copper hydroxide of metal alkali One or more of cobalt hydroxide, tin hydroxide and nickel hydroxide, or non-metallic oxides of silicon dioxide and / or phosphorus pentoxide, boric acid, silicic acid and phosphoric acid, or non-metallic salts That is One or more of ammonium dihydrogen, ammonium phosphate, and ammonium sulfate, one or more of copper, lead, antimony, tin, cobalt, and nickel as simple metals, or one of silicon, sulfur, and boron as simple metals It is a seed | species or more, The manufacturing method of the composite hard carbon negative electrode material of the lithium ion battery of Claim 9 characterized by the above-mentioned.