CN115458742A - Hard carbon material and preparation method thereof - Google Patents

Hard carbon material and preparation method thereof Download PDF

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CN115458742A
CN115458742A CN202211277212.5A CN202211277212A CN115458742A CN 115458742 A CN115458742 A CN 115458742A CN 202211277212 A CN202211277212 A CN 202211277212A CN 115458742 A CN115458742 A CN 115458742A
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temperature
hard carbon
temperature carbonization
carbon material
preparation
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胡亮
彭天权
俞有康
章镇
陈厚富
谭桂明
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Ganzhou Litan New Energy Technology Co ltd
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    • 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
    • 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
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • 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
    • C01P2006/16—Pore diameter
    • C01P2006/17—Pore diameter distribution
    • 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
    • C01P2006/40—Electric properties
    • 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

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  • Carbon And Carbon Compounds (AREA)

Abstract

The invention relates to the technical field of electrode materials, in particular to a hard carbon material and a preparation method thereof. The invention provides a preparation method of a hard carbon material, which comprises the following steps: sequentially carrying out low-temperature carbonization and particle shaping on a carbon source to obtain a precursor material; sequentially carrying out hole expanding, spray granulation and high-temperature carbonization on the precursor material to obtain the hard carbon material; the temperature of the low-temperature carbonization is lower than that of the high-temperature carbonization. The hard carbon material prepared by the preparation method has high specific capacity and high first coulombic efficiency.

Description

Hard carbon material and preparation method thereof
Technical Field
The invention relates to the technical field of electrode materials, in particular to a hard carbon material and a preparation method thereof.
Background
A secondary battery (Rechargeable battery) is also called a Rechargeable battery or a secondary battery, and refers to a battery that can be continuously used by activating an active material by charging after the battery is discharged. The main secondary batteries in the market at present are lithium ion batteries, sodium ion batteries, super capacitors, nickel hydrogen batteries, nickel cadmium batteries, lead acid (or lead storage) batteries, rechargeable alkaline batteries and the like. The negative electrode material is a carrier of ions and electrons in the charging process of the secondary battery and plays a role in storing and releasing energy. The anode material is an important constituent of the secondary battery.
The negative electrode material can be divided into two main categories, namely carbon material and non-carbon material. The carbon material comprises graphite, hard carbon, soft carbon, mesocarbon microbeads and the like, and the non-carbon material comprises a silicon-based material, lithium titanate, a tin-based material and the like. The negative electrode material which is most widely applied and has the largest output and sales volume in the current market is graphite, but the theoretical specific capacity of the graphite negative electrode is lower and is only 372 mA.h/g, and the large-rate continuous charge and discharge capacity and the low-temperature performance are difficult to effectively improve, so that the development of a novel lithium ion battery negative electrode material which has high specific capacity, excellent rate performance and good low-temperature performance is an important direction of current research.
Hard carbon refers to a carbon material that is difficult to graphitize, and is formed by thermal decomposition of a high molecular polymer. The hard carbon has a staggered layered structure, the distance between carbon layers is large, and lithium ions can be inserted and extracted from different angles, so that the diffusion speed of the lithium ions is improved, and the rapid charge and discharge of the material can be realized. In addition, due to the existence of a large number of micropores, the hard carbon material has more lithium embedding spaces, the reversible specific capacity is generally 300-700 mA.h/g, even can exceed 1000 mA.h/g and is far larger than the theoretical capacity 372 mA.h/g of graphite. The hard carbon material has a stable structure and very small volume expansion during charge and discharge, so that it has excellent long cycle properties. The lithium intercalation potential of the hard carbon can be higher than 0.2V, and the safety performance is good. The hard carbon material has the excellent comprehensive performance, and is matched with the long-cycle performance requirement of a future pure power battery/energy storage battery and the high-energy density and high-power requirement of a 48V start-stop battery/PHEV power battery/consumer battery/super capacitor. Meanwhile, the hard carbon has large carbon layer spacing and is considered as the negative electrode material with the optimal comprehensive performance in the application of the sodium ion battery at present.
The structural advantages of the hard carbon material bring corresponding disadvantages, and the internal structure of the hard carbon material generates a large amount of lattice defects in the preparation process, so that lithium ions are not only inserted between carbon atom layers but also inserted into the lattice defects in the lithium insertion process, and although the specific capacity of the hard carbon negative electrode can be obviously improved, the lattice defects also cause the phenomenon of low first coulombic efficiency of the hard carbon negative electrode material.
Disclosure of Invention
The invention aims to provide a hard carbon material and a preparation method thereof.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a hard carbon material, which comprises the following steps:
sequentially carrying out low-temperature carbonization and particle shaping on a carbon source to obtain a precursor material;
carrying out hole expanding, spray granulation and high-temperature carbonization on the precursor material in sequence to obtain the hard carbon material;
the temperature of the low-temperature carbonization is lower than that of the high-temperature carbonization.
Preferably, the carbon source comprises one or more of biomass materials, resinous materials, carbon products and sugar substances.
Preferably, the biomass material comprises one or more of rice hull, peanut shell, pistachio nut shell, apricot shell, walnut shell, pine cone, rice, coconut shell, bamboo, corn cob, rape straw and bagasse;
the resin material comprises one or more of polyvinyl chloride resin, acrylic resin, phenolic resin, epoxy resin, polyester resin and polyamide resin;
the carbon product comprises one or more of petroleum coke, pitch coke and coal-based coke;
the saccharide substance comprises one or more of fructose, mannose, sucrose, glucose, galactose, aminosugar, ribose, starch, cellulose, polysaccharide, pectin, pentose, mannose, chitin, maltose, glycogen and inulin.
Preferably, the low-temperature carbonization is carried out in an air atmosphere or a protective atmosphere, the temperature of the low-temperature carbonization is 150-500 ℃, and the heat preservation time is 2-12 h;
median particle diameter D of the precursor material 50 Is 3-1000 μm.
Preferably, the reaming comprises the steps of:
and mixing the precursor material, the nitrogen-containing organic matter and the metal-containing compound, and sintering.
Preferably, the mass ratio of the precursor material, the nitrogen-containing organic substance and the metal-containing compound is 100: (1-20): (10-100);
the nitrogen-containing organic matter comprises one or more of hexadecyl ammonium bromide, hexadecyl trimethyl ammonium bromide and hexamethylene tetramine;
the metal-containing compound comprises one or more of aluminum oxide, magnesium nitrate, magnesium chloride, zinc chloride and sodium chloride.
Preferably, the sintering is carried out in an air atmosphere or a protective atmosphere, the sintering temperature is 200-600 ℃, and the heat preservation time is 2-10 h.
Preferably, the inlet temperature of the spray granulation is 180-250 ℃, the outlet temperature is 100-150 ℃, and the rotating speed of an atomizing disk of a spray granulating agent adopted by the spray granulation is more than or equal to 6000rpm.
Preferably, the high-temperature carbonization is carried out in an air atmosphere or a protective atmosphere, the temperature of the high-temperature carbonization is 1000-1600 ℃, and the heat preservation time is 2-10 h.
The invention also provides the hard carbon material prepared by the preparation method in the technical scheme, wherein the mass percentage of carbon elements in the hard carbon material is more than or equal to 95%, the carbon layer spacing is 0.35-0.42 nm, and the pore volume with the pore diameter of more than or equal to 30nm accounts for more than 50% of the total pore volume.
The invention provides a preparation method of a hard carbon material, which comprises the following steps: sequentially carrying out low-temperature carbonization and particle shaping on a carbon source to obtain a precursor material; sequentially carrying out hole expanding, spray granulation and high-temperature carbonization on the precursor material to obtain the hard carbon material; the temperature of the low-temperature carbonization is lower than that of the high-temperature carbonization. The preparation method can effectively avoid the volume expansion of the raw materials for preparing the hard carbon in the sintering process through low-temperature carbonization and high-temperature carbonization in sequence, so that the material has higher compaction density. The pore diameter of the finally prepared hard carbon material can be adjusted through the pore enlarging treatment, so that the pore diameter of the hard carbon material reaches an optimal value, and further, more optimal specific capacity and initial coulombic efficiency are obtained. By adopting atomization granulation, powder and liquid in the slurry obtained after reaming can be separated to achieve the aim of drying, and the particle size and the particle morphology of atomized particles can be adjusted; the price of the preparation raw materials is low, the preparation process and equipment are mature, and the method is suitable for large-scale production.
The invention also provides the hard carbon material prepared by the preparation method in the technical scheme, the mass percentage content of carbon elements in the hard carbon material is more than or equal to 95%, the carbon layer spacing is 0.35-0.42 nm, and the pore volume with the pore diameter of more than or equal to 30nm accounts for more than 50% of the total pore volume. The hard carbon material has high specific capacity, the first reversible specific capacity is more than 400 mA.h/g, and the first coulombic efficiency is more than 80% in a lithium ion battery test system; in a sodium ion battery test system, the first reversible specific capacity is more than 300 mA.h/g, and the first coulombic efficiency is more than 85%; the aperture of the hard carbon material is larger than or equal to 30nm, and the increase of the aperture is beneficial to the de-intercalation of ions in the charge and discharge process, so that the material has better dynamic performance.
Drawings
Fig. 1 is an SEM image of a hard carbon material prepared in example 1;
FIG. 2 is a pore size distribution diagram of a hard carbon material prepared in example 1;
fig. 3 is a first charge-discharge curve of a lithium button cell made of a hard carbon material prepared in example 1;
fig. 4 is a first charge and discharge curve of the sodium button cell of the hard carbon material prepared in example 1.
Detailed Description
The invention provides a preparation method of a hard carbon material, which comprises the following steps:
sequentially carrying out low-temperature carbonization and particle shaping on a carbon source to obtain a precursor material;
carrying out hole expanding, spray granulation and high-temperature carbonization on the precursor material in sequence to obtain the hard carbon material;
the temperature of the low-temperature carbonization is lower than that of the high-temperature carbonization.
In the present invention, all the starting materials for the preparation are commercially available products known to those skilled in the art unless otherwise specified.
According to the invention, a carbon source is carbonized at low temperature to obtain a precursor material.
In the present invention, the carbon source preferably includes one or more of biomass material, resinous material, carbon product and saccharide; the biomass material preferably comprises one or more of rice hull, peanut shell, pistachio nut shell, apricot shell, walnut shell, pine cone, rice, coconut shell, bamboo, corn cob, rape straw and bagasse; the resin material preferably comprises one or more of polyvinyl chloride resin, acrylic resin, phenolic resin, epoxy resin, polyester resin and polyamide resin; the carbon product preferably comprises one or more of petroleum coke, pitch coke and coal-based coke; the saccharide preferably comprises one or more of fructose, mannose, sucrose, glucose, galactose, aminosugar, ribose, starch, cellulose, polysaccharide, pectin, pentose, mannose, chitin, maltose, glycogen and inulin; when the carbon source is more than two of the above specific choices, the present invention does not have any special limitation on the ratio of the above specific substances, and the specific substances may be mixed according to any ratio.
In the present invention, the low-temperature carbonization is preferably performed in an air atmosphere or a protective atmosphere; the protective atmosphere is preferably a nitrogen atmosphere, a helium atmosphere, a neon atmosphere or an argon atmosphere; the temperature of the low-temperature carbonization is preferably 150-500 ℃, more preferably 200-400 ℃, and most preferably 250-350 ℃; the holding time is preferably 2 to 12 hours, more preferably 4 to 10 hours, and most preferably 5 to 6 hours.
In the invention, in the low-temperature carbonization process, the carbon source can be subjected to dehydration and deashing reaction to a certain extent to generate a large amount of volatile components, and after the low-temperature carbonization, the carbon residue rate of the carbon source is between 30 and 80 percent, and a certain curing effect is realized, so that the subsequent process is convenient to carry out; some cross-linking reaction also occurs when the carbon source is a carbohydrate.
In the present invention, the low-temperature carbonization is preferably performed in a box furnace, a tube furnace, a rotary kiln, a roller kiln, a pusher kiln, or a shuttle kiln. In the present invention, the initial oxygen content of the apparatus is preferably 100ppm or less.
After the low-temperature carbonization is finished, the invention also preferably comprises the step of shaping particles; the method of shaping the particles is preferably pulverization. The process of the invention is not limited in any way, and the process known to those skilled in the art is adopted to ensure the median particle diameter D of the precursor material obtained after the pulverization 50 Is 3-1000 μm.
In the invention, the equipment used for crushing is preferably a crusher, a mechanical crusher or a jet mill; the crusher is preferably a jaw crusher, a roller crusher, a double-roller crusher, a hammer crusher, a counterattack crusher or a vertical crusher; the mechanical pulverizer is preferably a universal pulverizer, a cryogenic pulverizer, a mechanical hammer mill or a superfine impact mill; the jet mill is preferably a flat jet mill, a fluidized bed counter-jet mill, a circulating tube jet mill, a counter-jet mill or a target jet mill.
After the precursor material is obtained, the hard carbon material is obtained by sequentially carrying out hole expanding, spray granulation and high-temperature carbonization on the precursor material.
In the present invention, the reaming preferably comprises the steps of:
and mixing the precursor material, the nitrogen-containing organic matter and the metal-containing compound, and sintering.
In the present invention, the mass ratio of the precursor material, the nitrogen-containing organic substance, and the metal-containing compound is preferably 100: (1-20): (10 to 100), more preferably 100: (5-15): (30 to 80), most preferably 100: (8-12): (50-60).
In the present invention, the nitrogen-containing organic substance preferably includes one or more of hexadecyl amine, hexadecyl trimethyl ammonium bromide and hexamethylene tetramine, and when the nitrogen-containing organic substance is two or more of the above specific choices, the present invention does not have any special limitation on the ratio of the specific substances, and the specific substances may be mixed according to any ratio.
In the present invention, the metal-containing compound preferably includes one or more of aluminum oxide, magnesium nitrate, magnesium chloride, zinc chloride and sodium chloride; when the metal-containing compound is more than two of the above specific choices, the present invention does not have any special limitation on the ratio of the above specific materials, and the metal-containing compound can be mixed according to any ratio.
In the present invention, the mixing is preferably wet mixing; the mixing medium for wet mixing is preferably one or more of water, absolute ethyl alcohol and isopropanol; when the mixed medium is more than two of the above specific choices, the present invention does not have any special limitation on the proportion of the above specific substances, and the specific substances can be mixed according to any proportion. The amount of the mixing medium used in the present invention is not particularly limited, and may be an amount well known to those skilled in the art.
After the mixing is completed, the present invention also preferably includes drying; the drying mode is preferably drying; the drying process is not limited in any way, and can be performed by a process known to those skilled in the art.
In the present invention, the sintering is preferably performed in an air atmosphere or a protective atmosphere, and the protective atmosphere is preferably a nitrogen atmosphere, a helium atmosphere, a neon atmosphere, or an argon atmosphere; the sintering temperature is preferably 200-600 ℃, more preferably 300-500 ℃, and most preferably 350-450 ℃; the holding time is preferably 2 to 10 hours, more preferably 4 to 8 hours, and most preferably 5 to 6 hours.
In the invention, in the sintering process, in the temperature gradual rising process, the nitrogen-containing organic matter and the metal-containing compound are firstly cured and uniformly dispersed in the particles, and when the temperature gradually rises, the metal-containing compound belongs to strong Lewis acid and can generate a large amount of pores on the surfaces and in the particles; meanwhile, the nitrogen-containing organic matter is also one of the pore-forming agents, can be decomposed at a high temperature and has a hole expanding effect.
The sintering is preferably completed and then cooling is also included; the cooling process is not particularly limited in the present invention, and may be performed by a process known to those skilled in the art.
After the cooling is completed, the invention also preferably comprises acid washing or alkali washing; the pickling solution adopted by the pickling preferably comprises one or more of hydrofluoric acid, sulfurous acid, phosphoric acid, nitrous acid, sulfuric acid, hydrochloric acid and nitric acid; the alkaline washing solution adopted by the alkaline washing preferably comprises one or more of a sodium hydroxide solution, a lithium hydroxide solution, a calcium hydroxide solution and a potassium hydroxide solution. The concentrations of the acid washing solution and the alkali washing solution are not particularly limited in the present invention, and may be those known to those skilled in the art. In the present invention, the acid washing or alkali washing is preferably performed under heating and stirring conditions; the conditions for heating and stirring are not particularly limited in the present invention, and may be those well known to those skilled in the art.
In the invention, the nitrogen-containing organic matter is used as a precipitator and a pore-expanding agent, the metal-containing compound is used as a pore-expanding template, sintering and curing are carried out, and finally the pore-expanding template is removed by acid washing or alkali washing, so that the size of micropores in the precursor material can be obviously expanded, and the hard carbon material with adjustable pore diameter is obtained.
After the acid washing or the alkali washing is completed, the invention also preferably comprises water washing, and the process of the water washing is not limited in any way, and the obtained material is close to neutrality by adopting the process well known to the skilled person.
In the present invention, the inlet temperature of the spray granulation is preferably 180 to 250 ℃, more preferably 190 to 240 ℃, and most preferably 200 to 230 ℃; the outlet temperature is preferably 100 to 150 ℃, more preferably 110 to 140 ℃, and most preferably 120 to 130 ℃; the rotating speed of an atomizing disk of the spray granulating agent adopted by the spray granulation is preferably more than or equal to 6000rpm.
In the present invention, the equipment used for spray granulation is preferably a centrifugal spray granulator or a pressure spray granulator.
In the present invention, the high-temperature carbonization is preferably performed in an air atmosphere or a protective atmosphere, and the protective atmosphere is preferably a nitrogen atmosphere, a helium atmosphere, a neon atmosphere, or an argon atmosphere; the temperature of the high-temperature carbonization is preferably 1000-1600 ℃, more preferably 1100-1500 ℃, and most preferably 1200-1300 ℃; the holding time is preferably 2 to 10 hours, more preferably 4 to 8 hours, and most preferably 5 to 6 hours. In the present invention, the high-temperature carbonization is preferably performed in a carbonization furnace, and the initial oxygen content of the carbonization furnace is preferably 100ppm or less.
The invention also provides the hard carbon material prepared by the preparation method in the technical scheme, wherein the mass percentage of carbon elements in the hard carbon material is more than or equal to 95%, the carbon layer spacing is 0.35-0.42 nm, and the pore volume with the pore diameter of more than or equal to 30nm accounts for more than 50% of the total pore volume.
In the present invention, the hard carbon material preferably has a specific surface area of 1 to 8m 2 Per g, median particle diameter D 50 Preferably 3 to 15 μm.
In the present invention, the hard carbon material is preferably applied to a secondary battery.
In the invention, the conductive agent in the secondary battery is preferably one or more of SUPER-P, ketjen black, acetylene black, carbon nanotubes and KS-6; when the conductive agents are more than two of the above specific choices, the present invention does not have any special limitation on the proportion of the specific substances, and the specific substances can be mixed according to any proportion. In the invention, the binder adopted for preparing the electrode pole piece in the secondary battery is preferably one or more of CMC, SBR, PVDF, LA133 and BP-7; when the binder is more than two of the above specific choices, the invention does not have any special limitation on the proportion of the specific substances, and the specific substances are mixed according to any proportion. In the invention, the solvent used for preparing the electrode plate in the secondary battery is preferably ultrapure water or methyl pyrrolidone. In the invention, the diaphragm adopted by the secondary battery is preferably coated by three layers of PP/PE/PP, two layers of PP/PE or PP + ceramics; the total thickness of the PE + ceramic coating is preferably 10 to 50 μm. In the present invention, the current collector used for the secondary battery is preferably a commercial aluminum foil having a thickness of 13 to 30 μm or a copper foil having a thickness of 4 to 20 μm.
The hard carbon material and the method for preparing the same according to the present invention will be described in detail with reference to examples, but they should not be construed as limiting the scope of the present invention.
Example 1
1kg of apricot shells are placed in a box type furnace, low-temperature carbonization is carried out in nitrogen atmosphere, the initial oxygen content in a carbonization furnace is controlled to be less than or equal to 100ppm, the low-temperature carbonization temperature is 350 ℃, the time is 6 hours, the obtained carbonized materials are crushed by a crusher and then crushed by a jet mill, and precursor materials with the median particle size of 5.3 mu m are obtained;
stirring and mixing 0.2kg of the precursor material and 2kg of pure water, then adding 0.01kg of hexadecylamine, uniformly mixing, adding 0.1kg of magnesium oxide (the mass ratio of the precursor material to the hexadecylamine to the magnesium oxide is 100: 5), uniformly stirring, then drying, sintering the dried material (the sintering temperature is 500 ℃, the time is 6 h), naturally cooling, placing the sintered material in excessive dilute hydrochloric acid, heating and stirring for more than 12h, and finally repeatedly cleaning with pure water until the material is nearly neutral to obtain a product system;
performing spray granulation on the product system (the inlet temperature of a spray granulator used for spray granulation is 230 ℃, the outlet temperature of the spray granulator used for spray granulation is 140 ℃, and the rotating speed of an atomizing disc is 10000 rpm) to obtain dried powder;
putting the dried powder into a carbonization furnace, and carrying out high-temperature carbonization in a nitrogen atmosphere (the initial oxygen content in the carbonization furnace is less than or equal to 100ppm, the high-temperature carbonization temperature is 1400 ℃, and the time is 4 hours) to obtain the hard carbon material(median particle diameter D of the hard carbon material 50 =6.4 μm and a specific surface area of 2.8m 2 Water content 0.132%) per gram.
Example 2
Placing 1kg of coconut shell in a box-type furnace, carbonizing at low temperature in nitrogen atmosphere, controlling the initial oxygen content in the carbonization furnace to be less than or equal to 100ppm, the low-temperature carbonization temperature to be 200 ℃, and the time to be 8 hours, crushing the obtained carbonized material by a crusher, and then crushing by a jet mill to obtain a precursor material with the median particle size of 8.7 mu m;
stirring and mixing 0.2kg of the precursor material and 2kg of pure water, then adding 0.02kg of hexadecylamine, uniformly mixing, adding 0.14kg of magnesium nitrate (the mass ratio of the precursor material to the hexadecylamine to the magnesium nitrate is 100: 10), uniformly stirring, then drying, sintering the dried material (the sintering temperature is 500 ℃ for 6 hours), naturally cooling, placing the sintered material in excessive dilute hydrochloric acid, heating and stirring for more than 12 hours, and finally repeatedly cleaning with pure water until the material is nearly neutral to obtain a product system;
performing spray granulation on the product system (the inlet temperature of a spray granulator used for spray granulation is 200 ℃, the outlet temperature is 105 ℃, and the rotating speed of an atomizing disc is 7000 rpm) to obtain dried powder;
putting the dried powder into a carbonization furnace, and carrying out high-temperature carbonization in a nitrogen atmosphere (the initial oxygen content in the carbonization furnace is less than or equal to 100ppm, the carbonization temperature is 1100 ℃, and the time is 10 hours) to obtain a hard carbon material (the median particle diameter D of the hard carbon material) 50 =10.4 μm and a specific surface area of 3.2m 2 Water content 0.158%) per gram.
Example 3
1kg of phenolic resin is placed in a box-type furnace, low-temperature carbonization is carried out in nitrogen atmosphere, the initial oxygen content in a carbonization furnace is controlled to be less than or equal to 100ppm, the low-temperature carbonization temperature is 300 ℃, the time is 2 hours, the obtained carbonized material is crushed by a crusher and then crushed by a jet mill, and a precursor material with the median particle size of 3.2 mu m is obtained;
stirring and mixing 0.2kg of the precursor material and 2kg of pure water, then adding 0.001kg of hexadecyl trimethyl ammonium bromide, uniformly mixing, adding 0.2kg of alumina (the mass ratio of the precursor material to the hexadecyl trimethyl ammonium bromide to the alumina is 100: 2), uniformly stirring, then drying, sintering the dried material (the sintering temperature is 500 ℃ and the time is 6 hours), naturally cooling, placing the sintered material in excessive dilute hydrochloric acid, heating and stirring for more than 12 hours, and finally repeatedly cleaning with pure water until the material is close to neutral to obtain a product system;
performing spray granulation on the product system (the inlet temperature of a spray granulator used for spray granulation is 190 ℃, the outlet temperature is 110 ℃, and the rotating speed of an atomizing disc is 8000 rpm) to obtain dried powder;
putting the dried powder into a carbonization furnace, and carrying out high-temperature carbonization in a nitrogen atmosphere (the initial oxygen content in the carbonization furnace is less than or equal to 100ppm, the high-temperature carbonization temperature is 1200 ℃, and the time is 2 hours) to obtain a hard carbon material (the median particle diameter D of the hard carbon material) 50 =5.9 μm and a specific surface area of 4.6m 2 Water content 0.179%/g).
Example 4
1kg of petroleum coke is placed in a box type furnace, low-temperature carbonization is carried out in nitrogen atmosphere, the initial oxygen content in a carbonization furnace is controlled to be less than or equal to 100ppm, the low-temperature carbonization temperature is 500 ℃, the time is 2 hours, the obtained carbonized material is crushed by a crusher and then crushed by a jet mill, and a precursor material with the median particle size of 9.2 mu m is obtained;
stirring and mixing 0.2kg of the precursor material and 2kg of pure water, then adding 0.04kg of hexamethylenetetramine, uniformly mixing, adding 0.04kg of magnesium chloride (the mass ratio of the precursor material to the hexamethylenetetramine to the magnesium chloride is 100: 20), uniformly stirring, then drying, sintering the dried material (the sintering temperature is 500 ℃, the time is 6 h), naturally cooling, placing the sintered material in excessive dilute hydrochloric acid, heating and stirring for more than 12h, and finally repeatedly cleaning with pure water until the material is nearly neutral to obtain a product system;
performing spray granulation on the product system (the inlet temperature of a spray granulator used for the spray granulation is 230 ℃, the outlet temperature is 130 ℃, and the rotating speed of an atomizing disc is 9000 rpm) to obtain dried powder;
putting the dried powder into a carbonization furnace, and carrying out high-temperature carbonization in a nitrogen atmosphere (the initial oxygen content in the carbonization furnace is less than or equal to 100ppm, the high-temperature carbonization temperature is 1300 ℃, and the time is 4 hours) to obtain a hard carbon material (the median particle diameter D of the hard carbon material is 50 =12.3 μm and a specific surface area of 5.3m 2 Water content 0.226% per gram).
Example 5
1kg of starch is placed in a box type furnace, low-temperature carbonization is carried out in nitrogen atmosphere, the initial oxygen content in the carbonization furnace is controlled to be less than or equal to 100ppm, the low-temperature carbonization temperature is 450 ℃, the time is 5 hours, the obtained carbonized material is crushed by a crusher and then crushed by a jet mill, and a precursor material with the median particle size of 12.3 mu m is obtained;
stirring and mixing 0.2kg of the precursor material and 2kg of pure water, then adding 0.03kg of hexamethylenetetramine, uniformly mixing, adding 0.12kg of sodium chloride (the mass ratio of the precursor material to the hexamethylenetetramine to the sodium chloride is 100: 15), uniformly stirring, then drying, sintering the dried material (the sintering temperature is 500 ℃, the time is 6 hours), naturally cooling, placing the sintered material in excessive dilute hydrochloric acid, heating and stirring for more than 12 hours, and finally repeatedly cleaning with pure water until the material is nearly neutral to obtain a product system;
performing spray granulation on the product system (the inlet temperature of a spray granulator used for spray granulation is 210 ℃, the outlet temperature is 120 ℃, and the rotating speed of an atomizing disc is 12000 rpm) to obtain dried powder;
putting the dried powder into a carbonization furnace, and carrying out high-temperature carbonization in a nitrogen atmosphere (the initial oxygen content in the carbonization furnace is less than or equal to 100ppm, the high-temperature carbonization temperature is 1300 ℃, and the time is 4 hours) to obtain a hard carbon material (the median particle diameter D of the hard carbon material is 50 =14.3 μm and a specific surface area of 2.8m 2 Water content 0.157%) per gram.
Comparative example 1
Referring to example 1, the only difference is that after low temperature carbonization, no particle shaping is performed.
Comparative example 2
Referring to example 1, the only difference is that no reaming is performed.
Comparative example 3
Referring to example 1, the only difference is that no nitrogen-containing organic substance was added during the hole expansion.
Comparative example 4
Referring to example 1, the only difference is that no metal-containing compound was added during the reaming process.
Comparative example 5
Referring to example 1, the only difference is that spray granulation was replaced with a stirring and drying method.
Test example 1
The hard carbon material prepared in example 1 was tested using a field emission Scanning Electron Microscope (SEM) (JSM-7800F); the test result is shown in fig. 1, and it can be seen from fig. 1 that the surface of the hard carbon material has a large number of pores and a large pore size;
determining the moisture content of the hard carbon materials prepared in examples 1 to 5 and comparative examples 1 to 5 by using a Karl moisture tester;
tap densities of the hard carbon materials prepared in examples 1 to 5 and comparative examples 1 to 5 were measured using a tap density analyzer (dandongbutot BT-311);
the hard carbon materials prepared in examples 1 to 5 and comparative examples 1 to 5 were subjected to a specific surface area test using Kang Da NOVA 4000e, usa, wherein fig. 2 is a pore size distribution diagram of the hard carbon material prepared in example 1, it can be seen from fig. 2 that the pore size distribution in the hard carbon material is 50nm or more, the median pore size is about 100nm, and peaks of micropores are not found in the diagram;
the test results are shown in table 1:
TABLE 1 physicochemical index parameters of hard carbon materials prepared in examples 1 to 5 and comparative examples 1 to 5
Figure BDA0003896848780000121
As can be seen from table 1, the hole expansion according to the present invention can expand the pore diameter of the hard carbon material, significantly reduce the moisture in the hard carbon material, and improve the specific surface area of the hard carbon material; the spray granulation technology can enable the hard carbon material to have a better grain size. In examples 1 to 5, the moisture of the hard carbon material changes to some extent under the adjustment of the preparation process parameters, and the most affected factor is the change of the pore-enlarging process, as in example 4, when the content of the inorganic compound is the lowest, the pore-enlarging effect is the worst, and the moisture content of the hard carbon negative electrode material is 0.226%; however, when the content ratio of the metal-containing compound is greatly excessive, as in example 3, the hole-expanding effect is not optimal, so the hole-expanding effect is also affected by the whole process, including the sintering process, the spray granulation process, and the like; in the comparative example 1, the obtained particles have obviously large particle size without particle reshaping, the ion diffusion path is increased, and the electrochemical performance of the prepared hard carbon cathode material is far inferior to that of the hard carbon cathode material in the example 1; in comparative examples 2-4, the precursor materials are not subjected to pore-forming, or no nitrogen-containing organic substance and metal-containing compound are added, and the moisture content of the obtained hard carbon material is more than 1% and is obviously higher than 0.132% in example 1; comparative example 5 the particle size of the hard carbon material obtained by the conventional stirring and drying method was significantly increased without using the spray granulation method, and the moisture content was also increased to 0.196%, which was significantly higher than that of example 1; and the increase of the moisture content causes the first reversible capacity and the first efficiency to be remarkably deteriorated.
Testing the lithium button cell:
mixing the hard carbon materials obtained in examples 1 to 5 and comparative examples 1 to 5, conductive carbon black and a binder in pure water according to a mass ratio of 96. Assembling a button half cell in a glove box filled with argon, wherein a counter electrode is a metal lithium sheet, a diaphragm is PE, and electrolyte is LiPF with the concentration of 1mol/L 6 EC/DMC (Vol 1:1). The charging and discharging test of the button cell is carried out, the test flow is 0.2C DC (direct current) to 0V,0.05C DC to 0V,0V CV (constant voltage) 50uA and 0.01C DC to 0V,0V CV 20uA, rest 10min,0.2C CC (constant current) to 2V. The first reversible capacity and efficiency of the carbon anode materials in examples and comparative examples were measured.
The test equipment of the button cell is a LAND cell test system of blue electronic corporation of Wuhan city.
Sodium electricity button type electrical test:
the hard carbon materials, the conductive carbon black and the binder obtained in examples 1 to 5 and comparative examples 1 to 5 were mixed in NMP in a drying room with a humidity of less than 10% according to a mass ratio of 90. Assembling a button type half cell in a glove box filled with argon, wherein a counter electrode is a metal sodium sheet, a diaphragm is PE, and electrolyte is NaPF with the concentration of 1mol/L 6 EC/DMCVol = 1:1). The charge and discharge test of the button cell is carried out, and the test flow is 0.1C CC 4.0V,4.0V CV 0.03C and 0.1C DC 2V. The first reversible capacity and efficiency of the sodium cathode materials in the examples and comparative examples were measured.
The test equipment of the button cell is a commercial LAND cell test system of blue electronic corporation of Wuhan.
The test results are shown in table 2:
table 2 electrochemical properties of hard carbon materials prepared in examples 1 to 5 and comparative examples 1 to 5
Figure BDA0003896848780000131
Figure BDA0003896848780000141
As can be seen from table 2, the first reversible capacity and the first coulombic efficiency of the hard carbon material of the present invention are significantly improved;
fig. 3 is a first charge-discharge curve of the lithium button cell made of the hard carbon material prepared in example 1, and as can be seen from fig. 3, in the lithium button cell made of the hard carbon material prepared in example 1, the lithium intercalation capacity is about 480mAh/g, the lithium deintercalation capacity (reversible capacity) is about 400mAh/g, and the first coulomb efficiency is about 83%;
fig. 4 is a first charge-discharge curve of the sodium-electricity button cell made of the hard carbon material prepared in example 1, and it can be seen from fig. 4 that the hard carbon material described in example 1 has a sodium insertion capacity of about 350mAh/g, a sodium removal capacity (reversible capacity) of about 305mAh/g, and a first coulombic efficiency of about 87% in sodium-electricity button cell.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and amendments can be made without departing from the principle of the present invention, and these modifications and amendments should also be considered as the protection scope of the present invention.

Claims (10)

1. A preparation method of a hard carbon material is characterized by comprising the following steps:
sequentially carrying out low-temperature carbonization and particle shaping on a carbon source to obtain a precursor material;
sequentially carrying out hole expanding, spray granulation and high-temperature carbonization on the precursor material to obtain the hard carbon material;
the temperature of the low-temperature carbonization is lower than that of the high-temperature carbonization.
2. The method of claim 1, wherein the carbon source comprises one or more of biomass materials, resinous materials, carbonaceous products, and sugar-based materials.
3. The method of claim 2, wherein the biomass material comprises one or more of rice hulls, peanut shells, pistachio shells, apricot shells, walnut shells, pine nuts, rice, coconut shells, bamboo, corn cobs, rape stalks and bagasse;
the resin material comprises one or more of polyvinyl chloride resin, acrylic resin, phenolic resin, epoxy resin, polyester resin and polyamide resin;
the carbon product comprises one or more of petroleum coke, pitch coke and coal-based coke;
the saccharide substance comprises one or more of fructose, mannose, sucrose, glucose, galactose, aminosugar, ribose, starch, cellulose, polysaccharide, pectin, pentose, mannose, chitin, maltose, glycogen and inulin.
4. The preparation method according to claim 1, wherein the low-temperature carbonization is carried out in an air atmosphere or a protective atmosphere, the temperature of the low-temperature carbonization is 150-500 ℃, and the holding time is 2-12 h;
median particle diameter D of the precursor material 50 Is 3-1000 μm.
5. The method of manufacturing of claim 1, wherein said reaming comprises the steps of:
and mixing the precursor material, the nitrogen-containing organic matter and the metal-containing compound, and sintering.
6. The method of claim 5, wherein the mass ratio of the precursor material, the nitrogen-containing organic substance, and the metal-containing compound is 100: (1-20): (10-100);
the nitrogen-containing organic matter comprises one or more of hexadecyl ammonium bromide, hexadecyl trimethyl ammonium bromide and hexamethylene tetramine;
the metal-containing compound comprises one or more of aluminum oxide, magnesium nitrate, magnesium chloride, zinc chloride and sodium chloride.
7. The method according to claim 5, wherein the sintering is carried out in an air atmosphere or a protective atmosphere, the sintering temperature is 200-600 ℃, and the holding time is 2-10 h.
8. The preparation method of claim 1, wherein the inlet temperature of the spray granulation is 180-250 ℃, the outlet temperature is 100-150 ℃, and the rotation speed of an atomizing disk of a spray granulating agent adopted by the spray granulation is more than or equal to 6000rpm.
9. The preparation method according to claim 1, wherein the high-temperature carbonization is carried out in an air atmosphere or a protective atmosphere, the temperature of the high-temperature carbonization is 1000 to 1600 ℃, and the holding time is 2 to 10 hours.
10. The hard carbon material prepared by the preparation method of any one of claims 1 to 9, wherein the mass percentage content of carbon elements in the hard carbon material is not less than 95%, the carbon layer spacing is 0.35 to 0.42nm, and the pore volume with the pore diameter of not less than 30nm accounts for more than 50% of the total pore volume.
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CN116161645A (en) * 2023-03-15 2023-05-26 赣州立探新能源科技有限公司 Spherical silicon-carbon anode material and preparation method and application thereof
CN116534838A (en) * 2023-05-16 2023-08-04 赣州立探新能源科技有限公司 Hard carbon material, preparation method and application thereof, and secondary battery
CN116621157A (en) * 2023-07-20 2023-08-22 河北科技大学 Preparation method of hard carbon material, hard carbon material and application
CN117069093A (en) * 2023-09-15 2023-11-17 福建省鑫森炭业股份有限公司 Preparation method of hard carbon anode material
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Publication number Priority date Publication date Assignee Title
CN116161645A (en) * 2023-03-15 2023-05-26 赣州立探新能源科技有限公司 Spherical silicon-carbon anode material and preparation method and application thereof
CN116161645B (en) * 2023-03-15 2024-02-23 赣州立探新能源科技有限公司 Spherical silicon-carbon anode material and preparation method and application thereof
CN116534838A (en) * 2023-05-16 2023-08-04 赣州立探新能源科技有限公司 Hard carbon material, preparation method and application thereof, and secondary battery
CN116621157A (en) * 2023-07-20 2023-08-22 河北科技大学 Preparation method of hard carbon material, hard carbon material and application
CN116621157B (en) * 2023-07-20 2023-09-29 河北科技大学 Preparation method of hard carbon material, hard carbon material and application
CN117069093A (en) * 2023-09-15 2023-11-17 福建省鑫森炭业股份有限公司 Preparation method of hard carbon anode material
CN117069093B (en) * 2023-09-15 2024-06-07 福建省鑫森炭业股份有限公司 Preparation method of hard carbon anode material
CN117486200A (en) * 2024-01-02 2024-02-02 赣州立探新能源科技有限公司 Hard carbon, preparation method thereof and secondary battery

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