CN117594794B - Hard carbon material, preparation method thereof, negative electrode material and sodium ion battery - Google Patents

Hard carbon material, preparation method thereof, negative electrode material and sodium ion battery Download PDF

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CN117594794B
CN117594794B CN202410075151.7A CN202410075151A CN117594794B CN 117594794 B CN117594794 B CN 117594794B CN 202410075151 A CN202410075151 A CN 202410075151A CN 117594794 B CN117594794 B CN 117594794B
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hard carbon
atmosphere
carbon material
groups
ion battery
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CN117594794A (en
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刘义
张云阳
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Wuhan Bisidi Battery Material Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
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    • H—ELECTRICITY
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    • 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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

The invention discloses a hard carbon material and a preparation method thereof, which utilize an atomic pair distribution function technology to deconstruct crystal information and lattice curvatureThe hard carbon material with the closed pore volume of 0.03-0.15 and the closed pore volume of 0.04-0.5cm 3·g‑1 has higher closed pore rate, high sodium storage capacity and better pore strength, is not easy to collapse in structure in the long-term charge and discharge process, and has high cycle stability.

Description

Hard carbon material, preparation method thereof, negative electrode material and sodium ion battery
Technical Field
The invention relates to the technical field of batteries, in particular to a hard carbon material, a preparation method thereof, and a negative electrode and an electrochemical device for an electrochemical device containing the hard carbon material.
Background
Sodium ion batteries are considered as an important choice for next generation secondary batteries due to the abundant sodium content in the crust and their higher energy density. For the negative electrode, because the radius of sodium ions is larger, when the traditional graphite is used as a sodium-electricity negative electrode material, only ether solvated sodium ions can form stable interlayer compounds with the graphite, and the graphite material can expand and shrink in volume along with the intercalation/deintercalation process of sodium ions, so that the graphite layer is broken. Such breakage can cause unrecoverable resistance to develop inside the battery, reducing battery performance and cycle life. Compared with graphite materials, the hard carbon materials can store desolvated sodium ions, and have better cycle stability in the intercalation/deintercalation process of the sodium ions. The hard carbon material can reduce precipitation of sodium metal, so that the problems of short circuit and safety of the battery are avoided, and the reliability and the service life of the battery are improved. And, the hard carbon material can provide greater charge storage capacity at the same volume or mass, thereby increasing the energy density of the battery and extending the run time of the battery. Meanwhile, the hard carbon material has higher thermal stability, and can keep better structural stability and electrochemical performance in a high-temperature environment. This makes hard carbon anodes potential for high temperature applications and rapid charge and discharge systems, meeting the needs of specific applications.
However, the existing hard carbon materials generally have the following problems:
1. The closed cell rate of hard carbon is not high: closed cells are proved to be the main sodium storage sites of the low voltage capacity of hard carbon, and the small closed cell amount can lead to the small low voltage capacity of hard carbon. Such low voltage capacity loss may result in a decrease in the energy density of the battery, affecting the service life and performance of the battery;
2. The strength of the closed cells is insufficient: the closed pores in the hard carbon material are mainly closed micropores or air holes, the structural strength is low, and the structural collapse is easy to occur in the long-term cyclic charge and discharge process, so that the structural stability and the cyclic life of the battery material are reduced, the capacity attenuation and the voltage attenuation of the sodium ion battery are caused in the long-term use process, and the performance and the reliability of the battery are influenced.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a hard carbon material and a preparation method thereof, wherein the hard carbon material has higher closed pore rate, thus having high sodium storage capacity, better pore strength, difficult structural collapse in the long-term charge and discharge process and high cycle stability.
To solve the problems, the invention adopts the following technical scheme:
Providing a hard carbon material, said hard carbon material having a lattice curvature 0.03-0.15, And the closed pore volume is 0.04-0.5cm 3·g-1;
Wherein the method comprises the steps of The standard distance value corresponding to the position of the 6 th peak in the atomic pair distribution function spectrum in the interval of 0-10A is used for comparing with graphite; /(I)A distance value corresponding to the position of the 6 th peak in an atomic pair distribution function spectrum of the hard carbon material in a 0-10A interval; /(I)0.56 A for silver target wavelength; the atomic pair distribution function spectrum is obtained through Fourier transformation of total scattering experimental data measured on a target material by an Ag target X-ray source total scattering experimental device.
In some embodiments, the hard carbon material feedstock is a biomass derivative carbon source or a polymeric organic matter, the biomass derivative carbon source being one or more of cellulose, lignin, or a saccharide.
In some embodiments, the hard carbon material is hard carbon particles, the hard carbon has an average particle size of 2-50 μm, and a carbon interlayer spacing d002 value of 0.35-0.40nm, which is obtained by an X-ray diffraction method using cukα rays as a radiation source, and is calculated based on the bragg equation.
In some embodiments, the hard carbon material has an average pore size of 0.5 to 5nm and a specific surface area of 0.5 to 20m 2·g-1.
In some embodiments, the hard carbon material has a burst strength of 14.5 to 22.8 kg-mm -2, as determined by the particle-particle crushing test (EGG) described by the ASTM D6175-3 method.
In some embodiments, the compacted density of the hard carbon material is 0.7 to 1.3g/cm 3.
The invention also provides a preparation method of the hard carbon material, which comprises the following steps:
Step (1): calcining a carbon source to obtain a hard carbon precursor;
Step (2): mixing and grinding the hard carbon precursor, a dispersing agent and an activating agent to obtain hard carbon precursor powder;
Step (3): mixing the hard carbon precursor powder with a cross-linking agent and a template agent, and performing medium-temperature carbonization treatment on the obtained mixture in an inert atmosphere to obtain a first carbonized product;
Step (4): carrying out high-temperature carbonization treatment on the first carbonized product obtained in the step (3) under an inert atmosphere or a mixed atmosphere of the inert atmosphere and an organic atmosphere to obtain a second carbonized product, namely obtaining the hard carbon material;
wherein the medium-temperature carbonization treatment temperature is 400-900 ℃ and the treatment time is 1-10h; the high-temperature carbonization treatment temperature is 900-1700 ℃, and the treatment time is 1-6h.
In some embodiments, further comprising step (5): and (3) carrying out microwave or medium-frequency heating treatment on the second carbonized product in an inert atmosphere to obtain the hard carbon material.
In some embodiments, in step (1), the carbon source is calcined at a temperature of 100 to 350 ℃ for a holding time of 1 to 20 hours; and/or the number of the groups of groups,
In the step (2), the hard carbon precursor powder has a sieving particle size of 250-800 meshes; and/or the number of the groups of groups,
The dispersing agent comprises one or more of sodium carboxymethyl cellulose, cetyl trimethyl ammonium bromide, p-phenylenediamine, silane coupling agent and tetracarboxylic dianhydride; and/or the number of the groups of groups,
The dispersant is used in an amount of 10 to 30 parts by weight, relative to 100 parts by weight of the hard carbon precursor; and/or the number of the groups of groups,
The activator comprises one or more of alkali metal hydroxide, metal halide and acid activator, wherein the alkali metal hydroxide comprises one or more of potassium hydroxide, sodium hydroxide, lithium hydroxide and cesium hydroxide, the metal halide comprises one or more of magnesium chloride, magnesium bromide, magnesium fluoride and calcium chloride, and the acid activator comprises one or more of phosphoric acid, sulfuric acid, hydrochloric acid and nitric acid; and/or the number of the groups of groups,
The activator is used in an amount of 5 to 20 parts by weight, relative to 100 parts by weight of the hard carbon precursor; and/or the number of the groups of groups,
In the step (3), the template agent is a nanoscale sacrificial template agent, and the particle size range is 1-20 nm; and/or the number of the groups of groups,
The template agent comprises one or more of ZnO, al 2O3 or MgO; and/or the number of the groups of groups,
Compared with 100 weight parts of the hard carbon precursor, the template agent is used in an amount of 1-10 weight parts; and/or the number of the groups of groups,
The cross-linking agent comprises one or more of peroxide and a multifunctional compound, wherein the peroxide comprises one or more of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide, and the multifunctional compound comprises one or more of hexamethylenetetramine, melamine and polyaniline; and/or the number of the groups of groups,
The crosslinking agent is used in an amount of 10 to 40 parts by weight, relative to 100 parts by weight of the hard carbon precursor; and/or the number of the groups of groups,
In the step (3), the inert atmosphere is one or more selected from nitrogen atmosphere, helium atmosphere, neon atmosphere, argon atmosphere, krypton atmosphere, xenon atmosphere and radon atmosphere; and/or the number of the groups of groups,
In the step (4), the inert atmosphere is one or more selected from nitrogen atmosphere, helium atmosphere, neon atmosphere, argon atmosphere, krypton atmosphere, xenon atmosphere and radon atmosphere; the organic matter atmosphere is formed by one or more of ethanol, methanol, acetone, glycol, benzyl alcohol, dodecane, diformate, glycerin, ethyl benzoate and N-methyl pyrrolidone.
In some embodiments, the high temperature carbonization is performed in an inert atmosphere or a mixed inert atmosphere with organic matter, wherein the volume ratio of organic matter atmosphere to inert atmosphere in the mixed inert atmosphere with organic matter is 1:20-1:2, preferably 1:10-1:5;
In some embodiments, in step (5), the microwave or intermediate frequency heating treatment is 300kHz-100GHz, preferably 500kHz-10GHz, more preferably 1-8 GHz, and the treatment time period is 30min-2h, more preferably 50min-1.5h.
Furthermore, the invention also provides a sodium ion battery anode material which is further prepared from the hard carbon material or the hard carbon material prepared by the preparation method of the hard carbon material.
Further, the invention also provides a sodium ion battery anode material which comprises the hard carbon material or the hard carbon material prepared by the preparation method of the hard carbon material.
Further, the invention also provides a sodium ion battery, which comprises the sodium ion battery anode material.
In the invention, the hard carbon material with specific high closed porosity and lattice curvature obviously improves the sodium storage performance and collapse resistance of the hard carbon material. The high pore rate provides more sodium storage space, increases the storage capacity of sodium ions in the interior of the particles, and when the curvature is constant, the stress distribution in the interior of the particles can be a certain value, so that the stress concentration is reduced, and the deformation and damage of the particles are reduced. This can improve collapse resistance of the hard carbon particles.
In the prior art, the high closed pore rate and the particle rupture strength are difficult to be combined, and the higher the closed pore rate is, the larger the defect degree of hard carbon is, and the strength of particles under high voltage or long cycle is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a graph of atomic pair distribution functions for examples 1-5 and comparative examples 1, 3 over a range of 1.5-5.5A.
FIG. 2 is a graph of the atomic pair distribution function of examples 1-5 and comparative examples 1,3 at 4.6-5.4A (peak position 6).
Fig. 3 is a schematic diagram of the atomic distribution structure of natural graphite.
Fig. 4 shows the initial charge and discharge test capacity variation trend of button cells using the hard carbon negative electrode materials of sodium ion batteries prepared in examples 1 to 5 and comparative examples 1 and 3.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present application based on the embodiments of the present application. Furthermore, it should be understood that the detailed description is presented herein for purposes of illustration and description only, and is not intended to limit the application. In the present application, unless otherwise specified, terms such as "upper" and "lower" are used specifically to refer to the orientation of the drawing in the figures. In addition, in the description of the present application, the term "comprising" means "including but not limited to". Various embodiments of the application may exist in a range of forms; it should be understood that the description in a range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the application; it is therefore to be understood that the range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that a description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2,3, 4, 5, and 6, wherever applicable. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.
In the present application, "and/or" describes an association relationship of an association object, meaning that there may be three relationships, for example, a and/or B, may mean: a alone, a and B together, and B alone. Wherein A, B may be singular or plural.
In the present application, "at least one", and the like, refer specifically to one or more, one or more; "plurality", and the like, specifically refer to two or more, two or more. "at least one", "at least one" or the like refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.
The application utilizes the atomic pair distribution function technology to deconstruct crystal information, determines the hard carbon material with specific high closed porosity and lattice curvature, and can obviously improve the sodium storage performance and collapse resistance of the hard carbon material.
Among them, the atomic pair distribution function technique (Atomic Pair Distribution Function, abbreviated as PDF) is a technique for describing the distance between atoms in a solid material or a liquid. The distribution of the distance between the atomic pairs is obtained by analyzing scattered rays in a crystalline or amorphous sample. According to the invention, the microstructure of the hard carbon material can be characterized and controlled by means of an atomic pair distribution function technology. The principle of the PDF technology is based on Bragg scattering and diffuse scattering signals in scattering experiments, and the intensity and scattering angle of scattered rays are recorded by utilizing interaction between the scattered rays and atoms in a sample. The distance distribution function between the atomic pairs can be obtained by performing an inverse fourier transform on the amplitude and phase of the scattered radiation. The invention can utilize neutron scattering source total scattering experimental device or X-ray synchrotron radiation source total scattering experimental device or Ag target X-ray source total scattering experimental device to detect the target material.
[ Curvature of lattice ]
The curvature of the crystal lattice is used for expressing the relative displacement between adjacent atoms or ions in the crystal, and represents the relative relation between the crystal with certain displacement and the standard crystal without displacement, so as to reflect the deformation of the crystal lattice. The relative displacement of adjacent atoms or ions of a crystal can be calculated by analyzing scattered radiation in a crystalline or amorphous sample using atomic pair distribution function techniques.
In an atomic pair distribution function, the Q value refers to the distance between an atomic pair, i.e. the distance between two adjacent atoms, in units of typically electron volts (eV), which represents the energy difference between an atomic pair, resulting from the overlapping of electron clouds between two atoms, so that the magnitude of the Q value is related to the electron cloud distribution of an atomic pair, and the definition of D in an atomic pair distribution function is a probability density function, indicating the probability of the presence of another atom at a specific distance r from an atom. The resolution of the PDF function real space (REAL SPACE, also referred to as r space) isThe high Q phase can improve real spatial resolution, but also tends to give false peak signals, requiring adjustment of the maximum Q value according to the wavelength of the synchrotron radiation light source, a common laboratory light source. The Fourier change formula of the atomic pair distribution function after data optimization is as follows:
the Lorch function is introduced as an M (Q) correction function, so that noise peaks in the Fourier change process can be reduced, and the probability maximum value of occurrence of the X-th main peak in the optimized hard carbon atom distribution function spectrum corresponding to the X-th shell outside the central C atom is obtained.
As shown in fig. 1 and 2, reflects the present inventionThe standard distance value corresponding to the position of the 6 th peak in the atomic pair distribution function spectrum of the natural graphite in the 0-10 a interval is defined as shown in fig. 1 and 2, that is, the lattice of the natural graphite does not introduce defects, and the position of the 6 th shell layer is the standard distance value (horizontal axis) relative to the central carbon atom; /(I)The distance value is defined as the distance value corresponding to the position of the 6 th peak in the atomic pair distribution function spectrum of the hard carbon material in the 0-10 a interval, namely the distance value (horizontal axis) between the central carbon atom and the position of the 6 th shell layer for the hard carbon material. Thus,/>Can reflect the displacement of the hard carbon material compared with the lattice structureAnd incident wavelength/>The ratio of (2) represents the tortuosity of the defective graphene in the hard carbon on the lattice structure. FIG. 3 is a schematic diagram showing the distribution structure of natural graphite atoms, wherein carbon atoms marked 0 are central atoms, and carbon atoms marked 1-6 reflect the relative positional relationship between the carbon atoms of layers 1-6 and the central carbon atoms.
The application provides a hard carbon material, wherein the curvature of the crystal lattice of the hard carbon material0.03 To 0.15, preferably 0.035 to 0.125, more preferably 0.04 to 0.12; wherein/>The standard distance value corresponding to the position of the 6 th peak in the atomic pair distribution function spectrum of the natural graphite in the interval of 0-10A; /(I)A distance value corresponding to the position of the 6 th peak in an atomic pair distribution function spectrum of the hard carbon material in a 0-10A interval; the atomic pair distribution function spectrum is obtained through Fourier transformation of total scattering experimental data measured on a target material by an Ag target X-ray source total scattering experimental device.
In this embodiment, the hard carbon material has a closed cell size of 0.04-0.5cm 3·g-1, preferably 0.1-0.45cm 3·g-1, and more preferably 0.25-0.4cm 3·g-1.
In this embodiment, the curvature and the closed pore volume of the hard carbon material are in the above ranges, so that the high closed pore rate and the particle rupture strength can be considered, the sodium storage performance and the collapse resistance of the hard carbon material are remarkably improved, and the capacity and the cycle performance of the sodium ion battery can be improved when the hard carbon material is applied to the sodium ion battery. The high pore rate provides more sodium storage space, increases the storage capacity of sodium ions in the interior of the particles, and when the curvature is constant, the stress distribution in the interior of the particles can be a certain value, so that the stress concentration is reduced, and the deformation and damage of the particles are reduced. This can improve collapse resistance of the hard carbon particles.
[ Hard carbon raw Material ]
The hard carbon material raw material can be one or more of biomass derivative carbon sources or high polymer organic carbon sources, wherein the high polymer organic carbon sources are one or more of phenolic resin, epoxy resin, melamine resin, polyfurfuryl alcohol, polyaniline, furfural resin, polyethylene glycol, polyethylene oxide, polyvinylidene fluoride, acrylic resin, polyacrylonitrile and oxidized asphalt;
In one embodiment, the biomass-derived carbon source is one or more of cellulose, lignin, or sugars, particularly from crops, oil crops and agricultural organic residues, forests, forest industry residues, etc., such as starch, coconut shells, almond shells, pistachio shells, hawaii shells, date pit shells, peanut shells, walnut shells, peach pit shells, cotton, wood chips, bamboo, straw, wood chips, pericarp, etc. In the embodiment, when the biomass derivative is used as a carbon source, the biomass derivative has a small benzene ring content, is not easy to rearrange in the carbonization process, and is more beneficial to obtaining a complete crystal structure, thereby realizing the controllability of the curvature of the crystal structure.
[ Hard carbon particle Structure ]
The hard carbon material in the invention is hard carbon particles, which can be in a sphere-like, block-like, flake-like and/or diamond-like shape, and from the viewpoint of compaction density, sphere-like hard carbon particles with a length-diameter ratio of 1.2 to 3 are preferred.
In one embodiment, the hard carbon material has an average particle size of 2 to 50 μm, preferably 5 to 45 μm, and more preferably 8 to 40 μm; the carbon layer spacing d002 value is 0.35-0.40nm, preferably 0.37-0.39nm. In this embodiment, the hard carbon material is not easy to agglomerate due to the average particle size and the carbon layer spacing in the above range, and has a good conductive path and sodium ion receptivity, wherein the larger 002 inter-plane spacing is conducive to rapid deintercalation of sodium ions inside the hard carbon material.
In this embodiment, the carbon layer spacing can be obtained by the following method: an X-ray diffraction method using cukα rays as a radiation source, and calculated based on the bragg equation. It is to be understood that the carbon-layer spacing may be referred to as a method for detecting a carbon material such as graphite or hard carbon, and the method for detecting the carbon-layer spacing is not limited herein.
In one embodiment, the hard carbon material has an average pore size of 0.5-5nm, preferably 1-4nm, more preferably 1.5-3nm, and a specific surface area of 0.5-20m 2·g-1, preferably 1-17 m 2·g-1, more preferably 5-70 m 2·g-1. It can be understood that the pore diameter in this embodiment specifically refers to the pore diameter of the closed pores or the micropores in the hard carbon material, and the pore diameter range and the specific surface area are favorable for absorption of sodium ions and formation of ion channels, and meanwhile, have better mechanical strength, and are not easy to collapse when used as the negative electrode material of the sodium ion battery.
In one embodiment, the compacted density of the hard carbon material is 0.7-1.3g/cm 3, preferably 0.8-1.2 g/cm 3.
And, in one embodiment, the hard carbon material has a burst strength of 14.5 to 22.8 kg-mm -2, more preferably 16.5 to 20 kg-mm -2, as determined by the particle-particle crushing test (EGG) described in ASTM D6175-3. Specifically, the fracture force of each particle of a representative sample containing at least 50 particles was measured and weighted by the length of the extrudate. The EGG test is an average of the breaking force measured on the whole of the sample particle and reduced to the unit of length of the extrudate.
The compaction density and the rupture strength are physical properties of the material under the control of the raw material selection, the pore size structure, the particle morphology and the specific surface area, and simultaneously, the compaction density and the rupture strength are beneficial to improving the mechanical property, the electrical conductivity and the chemical stability of the hard carbon material when the compaction density and the rupture strength are in the range defined by the invention.
[ Process step ]
The invention also provides a preparation method of the hard carbon material, which comprises the following steps:
Step (1): calcining a carbon source to obtain a hard carbon precursor;
Step (2): mixing and grinding the hard carbon precursor, a dispersing agent and an activating agent to obtain hard carbon precursor powder;
Step (3): mixing the hard carbon precursor powder with a cross-linking agent and a template agent, and performing medium-temperature carbonization treatment on the obtained mixture in an inert atmosphere to obtain a first carbonized product;
Step (4): carrying out high-temperature carbonization treatment on the first carbonized product obtained in the step (3) under an inert atmosphere or a mixed atmosphere of the inert atmosphere and an organic atmosphere to obtain a second carbonized product, namely obtaining the hard carbon material;
in the embodiment, through low-temperature precalcination, introduction of a dispersing agent, an activating agent, a cross-linking agent and a template agent, and two carbonization treatments of medium-temperature carbonization treatment and high-temperature carbonization treatment, the hard carbon material with specific bending degree and closed pore volume can be prepared, the high closed pore rate and the particle rupture strength can be considered, the sodium storage performance and the slump resistance of the hard carbon material are obviously improved, and the capacity and the cycle performance of a sodium ion battery can be improved when the hard carbon material is applied to the sodium ion battery.
In step (1):
The carbon source comprises one or more of biomass derivative carbon sources or high polymer organic matters, wherein the biomass derivative carbon sources are one or more of cellulose, lignin and saccharides. Reference is specifically made to the description of the hard carbon raw materials in the hard carbon materials section above, and no further description is given here.
In one embodiment, the calcination temperature of the carbon source is 100-350deg.C, specifically 150-300deg.C, 200-300 deg.C, 200-250deg.C, etc.; the heat preservation time is 1-20h, and can be specifically 1-18h, 2-12h, 5-10h, etc. In one embodiment, the calcination temperature is 150-300 ℃ and the holding time is 2-12 hours. The carbon source is subjected to low-temperature pre-calcination treatment, so that moisture, small molecules and other impurities can be removed.
In the step (2):
In some embodiments, the dispersant may include one or more of sodium carboxymethyl cellulose, cetyltrimethylammonium bromide, p-phenylenediamine, silane coupling agents, and tetracarboxylic dianhydrides, etc.; the dispersant is used in an amount of 1 to 30 parts by weight, preferably 10 to 30 parts by weight, relative to 100 parts by weight of the hard carbon precursor.
In some embodiments, in step (2), the activator comprises one or more of an alkali metal hydroxide comprising one or more of potassium hydroxide, sodium hydroxide, lithium hydroxide, cesium hydroxide, etc., a metal halide comprising one or more of magnesium chloride, magnesium bromide, magnesium fluoride, calcium chloride, etc., an acidic activator comprising one or more of phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, etc.; the activator is used in an amount of 5 to 20 parts by weight, preferably 10 to 18 parts by weight, relative to 100 parts by weight of the hard carbon precursor. The usage amount of the activator can lead the hard carbon to have better overall morphology, and can not damage production equipment, etc.
In some embodiments, the hard carbon precursor powder has a sieving particle size of 250-800 mesh, preferably 300-500 mesh. The powder particles in the above particle size range are advantageous for uniformly achieving mixing and carbonization in the subsequent step.
In the step (3):
in some embodiments, the crosslinking agent includes peroxides such as ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, and the like, polyfunctional compounds such as hexamethylenetetramine, melamine, polyaniline, and the like; the crosslinking agent may be used in an amount of 10 to 40 parts by weight, specifically 10 to 30 parts by weight, 20 to 30 parts by weight, etc., relative to 100 parts by weight of the hard carbon precursor.
In some embodiments, the templating agent is a nanoscale sacrificial templating agent having a particle size ranging from 1 to 20 nm, preferably from 2 to 12nm.
Specifically, the template agent can be selected from one or more of ZnO, al 2O3, mgO and the like, and is preferably a nanoscale sacrificial template agent ZnO. The template agent is used in an amount of 1 to 10 parts by weight, specifically 1 to 8 parts by weight, 3 to 5 parts by weight, etc., relative to 100 parts by weight of the hard carbon precursor.
In some embodiments, the medium temperature carbonization treatment temperature is 400-900 ℃, specifically 400-800 ℃, 500-800 ℃, 600-700 ℃, and the like; the treatment time is 1-10h, and can be specifically 2-6h, 3-6h, 4-5h, etc.
It will be appreciated that the inert gas referred to in the present application is used primarily to exclude oxygen and may be selected from one or more of nitrogen, helium, neon, argon, krypton, xenon, and radon, unless otherwise specified.
In this step, during the medium-temperature carbonization treatment, the hard carbon precursor undergoes a partial graphitization reaction to form a partial graphite crystallite. At the same time, the template agent occupies part of lattice positions to form defects and promote partial deviation of lattices, so that the curvature of the lattices of the hard carbon material is affected.
In the step (4):
the high temperature carbonization treatment temperature is 900-1700 ℃, specifically 900-1600 ℃, 1000-1500 ℃, 1000-1300 ℃, 1200-1600 ℃ and the like. The treatment time is 1-6h, and can be 1-4h, 2-3h, etc. In the process, the first carbonized product further undergoes partial graphitization reaction, partial carbon undergoes structural rearrangement and short-range diffusion to form lattice defects and bending, and after the template agent is removed at high temperature, the pore structure where the template agent is reserved is formed at the position.
It is understood that the high-temperature carbonization treatment temperature is higher than the medium-temperature carbonization treatment temperature, and the medium-temperature carbonization treatment temperature is 900 ℃, and the high-temperature carbonization treatment temperature is higher than 900 ℃.
The high-temperature carbonization treatment is performed in an inert atmosphere or a mixed atmosphere of an inert atmosphere and an organic substance, wherein the inert atmosphere can be described in the step (3), and a detailed description is omitted.
In some embodiments, the high temperature carbonization treatment is performed under an inert atmosphere mixed with the organic matter. Wherein the volume ratio of the organic atmosphere to the inert atmosphere in the mixed atmosphere of the inert atmosphere and the organic matter can be 1:20-1:2, and is preferably 1:10-1:5; in this embodiment, a small amount of organic atmosphere is introduced to facilitate the supplementation of a small amount of carbon source during the high-temperature carbonization process, and moderate adjustment of defects and specific surface area is performed, but the volume ratio of the organic atmosphere is too high, which may be unfavorable for the control of hard carbon crystal forms.
Specifically, the organic atmosphere is one or more selected from ethanol, methanol, acetone, glycol, benzyl alcohol, dodecane, diformate, glycerol, ethyl benzoate and N-methylpyrrolidone.
In one embodiment, impurities such as the cross-linking agent which is not reacted in the medium-temperature carbonization process in the step (3) in the first carbonized product are removed before the high-temperature carbonization treatment in the step (4); specifically, the first carbonized product may be washed with a solvent, which may be selected according to the kind of impurities such as a crosslinking agent, and the like, and is not limited herein.
In some embodiments, further comprising step (5): and carrying out microwave or medium-frequency heating treatment on the second carbonized product in an inert atmosphere to obtain the hard carbon material.
Wherein, the microwave or intermediate frequency heating treatment is 300kHz-100GHz, preferably 500kHz-10GHz, and more preferably 1-8 GHz; the treatment time is 30min-2h, more preferably 50min-1.5h. On one hand, microwave or medium-frequency heating treatment is helpful to promote the activation of the surface and the inside of pores of hard carbon, improve the specific surface area and the adsorption performance of the material, and on the other hand, the stress caused by bending of part of crystals is eliminated, so that the collapse resistance is further improved.
The application also provides a sodium ion battery anode material, wherein the sodium ion battery hard carbon anode material comprises the hard carbon material provided by the application, or the sodium ion battery hard carbon anode material comprises the hard carbon material prepared by the preparation method provided by the application.
Further, the application also provides a sodium ion battery, which comprises the sodium ion battery anode material provided by the application.
The hard carbon material provided by the application is used in the negative electrode of the sodium ion battery, so that the sodium ion battery has good capacity and cycle performance, and the negative electrode collapse caused by long-term use is avoided.
The technical solutions and effects of the present application will be described in detail by way of specific examples, comparative examples and experimental examples, which are only some examples of the present application, and are not intended to limit the present application in any way.
[ Measurement method ]
1-Lattice bending test
The total scattering experiments were performed on PA NALYTICAL EMPYREAN diffractometers. The detector used was a GaliPIX 3D detector of CdTe and the fourier transform correction and fitting used PDFgui software.
Is defined as a standard distance value corresponding to the position of the 6 th peak in an atomic pair distribution function spectrum of natural graphite in the interval of 0-10A/>The distance value corresponding to the position of the 6 th peak in the atomic pair distribution function spectrum of the hard carbon material in the 0-10A interval is defined, the measurement is carried out as shown in figure 1, and lambda is silver target wavelength 0.56A, thereby calculatingLattice curvature value.
Average particle diameter of 2-hard carbon particles
The particle size distribution was measured by a laser diffraction method using a Malvern Mastersizer2000E laser particle size analyzer, british, with reference to GB/T19077-2016.
Pore size of 3-hard carbon material
And (3) after drying and degassing pretreatment is carried out on the hard carbon anode material powder, testing is carried out by using an ASAP 2460-physical adsorption analyzer, the test atmosphere is nitrogen, different test pressures are regulated, the adsorption quantity of the nitrogen is measured respectively, and adsorption and desorption isotherms are drawn. And determining the shape of the hole according to the shape of the hysteresis loop, fitting the pore structure and the pore diameter distribution curve of the micropore structure by using a DFT model, and calculating to obtain the average pore diameter.
4-Closed pore volume
The high-orientation graphite is calculated by taking highly-oriented graphite with the density of 2.26g cm -3 as a reference substance and is measured by a true density test, wherein the true density is measured according to the GB/T24586-2009 standard, and the calculation formula V Closed cell ＝1/ρ True density -1/2.26 is calculated.
5-Specific surface area
Specific surface area of the anode active material was measured by a nitrogen adsorption/desorption method: the negative electrode active material was dried in a vacuum drying oven, then put into a sample tube, and measured in a specific surface area analyzer (Tristar ii 3020M).
6-Burst Strength
The determination is made by the particle-particle crush test (EGG) described by ASTM D6175-3. Which consists in measuring the breaking force of each particle of a representative sample comprising at least 50 particles. The results are weighted by the length of the extrudate. The EGG value is an average value of the breaking force measured on the whole of the sample particle and reduced to the unit of length of the extrudate.
7-Compaction Density
The processed negative electrode plate with the area S (the two sides of the negative electrode current collector are coated with the negative electrode active material layer) is weighed by using an electronic balance, the weight is recorded as W 1, and the thickness T 1 of the negative electrode plate is measured by using a ten-thousandth ruler; washing the negative electrode active material layer by using a solvent, drying, measuring the weight of a negative electrode current collector, recording as W 2, and measuring the thickness T 2 of the negative electrode current collector by using a ten-thousandth ruler; the compacted density pd= (W 1-W2)/[(T1-T2) ·s ] of the anode active material layer provided on the anode current collector side.
8-002 Interplanar spacing
The sample of hard carbon material was subjected to X-ray diffraction phase analysis by using cukα rays as a radiation source and calculated based on bragg equation.
Example 1
Step (1): weighing 4g of coconut shells, placing the coconut shells in a mortar, grinding for 10min until the coconut shells are ground into fine powder, then placing the ground coconut shell fine powder in a crucible, covering the crucible, heating to 200 ℃ at a heating rate of 3 ℃/min without covering a cover, preserving heat for 4h, and taking out the coconut shell fine powder after natural cooling;
Step (2): adding 0.6g of sodium carboxymethyl cellulose, 0.3g of sodium hydroxide and 10g of water, uniformly mixing with the coconut shell hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 1cm, the rotating speed is 300rpm, and the sieving granularity of about 8 hours to about 400 meshes of fine powder;
Step (3): drying the sieved hard carbon precursor, mixing with 0.9g of sodium persulfate and 0.15g of template ZnO with the particle size of 10nm, and carbonizing at 600 ℃ for 5 hours in nitrogen atmosphere to obtain a first carbonized product;
Step (4): carbonizing the first carbonized product at 1200 ℃ for 3 hours in a mixed atmosphere of ethanol/nitrogen=1:9, respectively washing three times by using deionized water and ethanol in sequence, and centrifuging to obtain a second carbonized product;
Step (5): and carrying out microwave treatment on the second carbonized product in a nitrogen atmosphere, wherein the frequency is 1GHz, and the treatment time is 1h, so as to obtain a final product.
Example 2
Step (1): weighing 4g of phenolic resin, placing in a mortar, grinding for 8min until the phenolic resin is ground into fine powder, then placing the fine powder of the ground phenolic resin in a crucible, covering the crucible, heating to 200 ℃ at a heating rate of 3 ℃/min without covering a cover, preserving heat for 4h, and taking out after natural cooling;
Step (2): adding 0.4g of hexadecyl trimethyl ammonium bromide, 0.2g of magnesium chloride and 10g of water, uniformly mixing with the phenolic resin hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 1cm, the rotating speed is 200rpm, and the sieving granularity of about 4 hours to about 600 meshes of fine powder;
step (3): drying the sieved hard carbon precursor, mixing with 0.5g of hexamethylenetetramine and 0.2g of template ZnO with the particle size of 30nm, and carbonizing at 400 ℃ for 3 hours in nitrogen atmosphere to obtain a first carbonized product;
step (4): removing impurities in the first carbonized product, carbonizing at 900 ℃ for 2 hours in a mixed atmosphere of acetone/nitrogen=1:9, respectively washing three times by using deionized water and ethanol in sequence, and centrifuging to remove a template agent to obtain a second carbonized product;
Step (5): and (3) carrying out medium-frequency treatment on the second carbonized product in a nitrogen atmosphere, wherein the frequency is 400KHz, and the treatment time is 30min, so as to obtain a final product.
Example 3
Step (1): weighing 4g of starch, placing in a mortar, grinding for 10min until the starch is ground into fine powder, then placing the ground starch fine powder in a crucible without a cover, heating to 200 ℃ at a heating rate of 3 ℃/min, preserving heat for 4h, and taking out after natural cooling;
Step (2): adding 0.8g of sodium carboxymethyl cellulose, 0.4g of sodium hydroxide and 10g of water, uniformly mixing with the starch hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 1cm, the rotating speed is 500rpm, and the sieving granularity of about 10 hours to about 200 meshes of fine powder;
Step (3): drying the sieved hard carbon precursor, mixing with 0.5g of sodium persulfate and 0.15g of template ZnO with the particle size of 10nm, and carbonizing at 800 ℃ in nitrogen atmosphere for 6 hours to obtain a first carbonized product;
Step (4): removing impurities in the first carbonized product, carbonizing at 1400 ℃ for 4 hours in a mixed atmosphere of ethanol/nitrogen=1:9, respectively washing three times by using deionized water and ethanol in sequence, and centrifuging to remove a template agent to obtain a second carbonized product;
Step (5): and carrying out microwave treatment on the second carbonized product in a nitrogen atmosphere, wherein the frequency is 8GHz, and the treatment time is 2 hours, so as to obtain a final product.
Example 4
Step (1): weighing 4g of coconut shells, placing the coconut shells in a mortar, grinding for 10min until the coconut shells are ground into fine powder, then placing the ground coconut shell fine powder in a crucible, covering the crucible, heating to 200 ℃ at a heating rate of 3 ℃/min without covering a cover, preserving heat for 4h, and taking out the coconut shell fine powder after natural cooling;
Step (2): adding 0.6g of sodium carboxymethyl cellulose, 0.3g of sodium hydroxide and 10g of water, uniformly mixing with the coconut shell hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 0.5cm, the rotating speed is 500rpm, and the sieving granularity of about 12 hours to about 250 meshes of fine powder;
Step (3): drying the sieved hard carbon precursor, mixing with 0.9g of sodium persulfate and 0.15g of template ZnO with the particle size of 20nm, and carbonizing at 600 ℃ for 5 hours in a nitrogen atmosphere to obtain a first carbonized product;
Step (4): removing impurities in the first carbonized product, carbonizing at 1200 ℃ for 3 hours in a mixed atmosphere of ethanol/nitrogen=1:9, respectively washing three times by using deionized water and ethanol in sequence, and centrifuging to remove a template agent to obtain a second carbonized product;
Step (5): and carrying out microwave treatment on the second carbonized product in a nitrogen atmosphere, wherein the frequency is 1GHz, and the treatment time is 1h, so as to obtain a final product.
Example 5
Step (1): weighing 4g of coconut shells, placing the coconut shells in a mortar, grinding for 10min until the coconut shells are ground into fine powder, then placing the ground coconut shell fine powder in a crucible, covering the crucible, heating to 200 ℃ at a heating rate of 3 ℃/min without covering a cover, preserving heat for 4h, and taking out the coconut shell fine powder after natural cooling;
Step (2): adding 0.6g of sodium carboxymethyl cellulose, 0.3g of sodium hydroxide and 10g of water, uniformly mixing with the coconut shell hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 1cm, the rotating speed is 300rpm, and the sieving granularity of about 8 hours to about 400 meshes of fine powder;
Step (3): drying the sieved hard carbon precursor, mixing with 0.9g of sodium persulfate and 0.15g of template ZnO with the particle size of 10nm, and carbonizing at 600 ℃ for 5 hours in nitrogen atmosphere to obtain a first carbonized product;
step (4): removing impurities in the first carbonized product, carbonizing at 1200 ℃ for 3 hours in a mixed atmosphere of ethanol/nitrogen=1:9, washing three times by using deionized water and ethanol respectively, and centrifuging to remove the template agent, so as to obtain a second carbonized product serving as a final product.
Comparative example 1
Step (1): weighing 4g of coconut shells, placing the coconut shells in a mortar, grinding for 10min until the coconut shells are ground into fine powder, then placing the ground coconut shell fine powder in a crucible, covering the crucible, heating to 200 ℃ at a heating rate of 3 ℃/min without covering a cover, preserving heat for 4h, and taking out the coconut shell fine powder after natural cooling;
Step (2): adding 0.6g of sodium carboxymethyl cellulose, 0.3g of sodium hydroxide and 10g of water, uniformly mixing with the coconut shell hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 1cm, the rotating speed is 300rpm, and the sieving granularity of about 8 hours to about 400 meshes of fine powder;
Step (3): drying the sieved hard carbon precursor, mixing with 0.9g of sodium persulfate and 0.15g of template ZnO with the particle size of 10nm, and carbonizing at 800 ℃ in nitrogen atmosphere for 10 hours to obtain a carbonized product;
Step (4): and (3) washing for three times by using deionized water and ethanol respectively, centrifuging to remove redundant impurities, and drying at 100 ℃ to obtain a final product.
Comparative example 2
Step (1): weighing 4g of coconut shells, placing the coconut shells in a mortar, grinding for 10min until the coconut shells are ground into fine powder, then placing the ground coconut shell fine powder in a crucible, covering the crucible, heating to 200 ℃ at a heating rate of 3 ℃/min without covering a cover, preserving heat for 4h, and taking out the coconut shell fine powder after natural cooling;
Step (2): adding 0.6g of sodium carboxymethyl cellulose, 0.3g of sodium hydroxide and 10g of water, uniformly mixing with the coconut shell hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 1cm, the rotating speed is 300rpm, and the sieving granularity of about 8 hours to about 400 meshes of fine powder;
step (3): drying the sieved hard carbon precursor, mixing with 0.9g of sodium persulfate and 0.15g of template ZnO with the particle size of 10nm, and carbonizing at 850 ℃ for 6.5h in nitrogen atmosphere to obtain a first carbonized product;
Step (4): removing impurities in the first carbonized product, carbonizing at 900 ℃ for 1.5 hours in a mixed atmosphere of ethanol/nitrogen=1:9, respectively washing three times by using deionized water and ethanol in sequence, and centrifuging to remove a template agent to obtain a second carbonized product;
Step (5): and carrying out microwave treatment on the second carbonized product in a nitrogen atmosphere, wherein the frequency is 1GHz, and the treatment time is 1h, so as to obtain a final product.
Comparative example 3
Step (1): weighing 4g of coconut shells, placing the coconut shells in a mortar, grinding for 10min until the coconut shells are ground into fine powder, then placing the ground coconut shell fine powder in a crucible, covering the crucible, heating to 200 ℃ at a heating rate of 3 ℃/min without covering a cover, preserving heat for 4h, and taking out the coconut shell fine powder after natural cooling;
Step (2): adding 0.6g of sodium carboxymethyl cellulose, 0.3g of sodium hydroxide and 10g of water, uniformly mixing with the coconut shell hard carbon precursor, grinding, wherein the grinding adopts zirconia balls with the size of 1cm, the rotating speed is 300rpm, and the sieving granularity of about 8 hours to about 400 meshes of fine powder;
Step (3): drying the sieved hard carbon precursor, mixing with 0.9g of sodium persulfate and 0.15g of template ZnO with the particle size of 10nm, and carbonizing at 350 ℃ for 2 hours in nitrogen atmosphere to obtain a first carbonized product;
step (4): removing impurities in the first carbonized product, carbonizing at 1200 ℃ for 6 hours in a mixed atmosphere of ethanol/nitrogen=1:9, respectively washing three times by using deionized water and ethanol in sequence, and centrifuging to remove a template agent to obtain a second carbonized product;
Step (5): and carrying out microwave treatment on the second carbonized product in a nitrogen atmosphere, wherein the frequency is 1GHz, and the treatment time is 1h, so as to obtain a final product.
The performance tests and indices of examples 1-5 and comparative examples 1-3 are shown in Table 1.
TABLE 1 Structure and mechanical Property testing of examples 1-5 and comparative examples 1-3
Cell performance test:
The sodium ion battery hard carbon negative electrode materials prepared in examples 1 to 5 and comparative examples 1 to 3 were prepared into slurry with conductive carbon black and a binder, uniformly coated on aluminum foil, and dried to prepare electrodes. Na 3V2(PO4)3 is used as a positive electrode, a glass fiber film is used as a diaphragm, a mixed solution of 1mol/L NaPF 6 and Ethylene Carbonate (EC) of dimethyl carbonate (DEC) =1:1vol% is used as an electrolyte, and 5wt% of fluoroethylene carbonate (FEC) is used as an additive to prepare a button cell; test conditions: the first discharge test uses 30mA/g discharge to 0.01V and recharges to 2.0V; the cycling performance test is carried out by using 50mA/g for constant-current charge and discharge test, the charge and discharge voltage range is 0.01-2V, and the test is carried out under the constant temperature condition of 25 ℃. The trend of capacity change in charge after the first discharge is shown in fig. 4.
TABLE 2 electrochemical performance testing of examples 1-5 and comparative examples 1-3
According to the structural characterization and fracture strength, the first charge specific capacity, the charge specific capacity after 500 cycles and several indexes of the capacity retention rate after 500 cycles, it can be seen that comparative example 1 is carbonized in one step, and is embodied on a hard carbon structure, and has high closed pore volume and reduced fracture strength, and comparative example 2 has long medium temperature treatment time and short high temperature treatment time, which results in too large lattice curvature and also affects fracture strength, and comparative example 3 has small lattice defect, small lattice curvature and small closed pore volume by changing the treatment process, so that the charge-discharge specific capacity is obviously insufficient. Comparative examples 1 to 3 were inferior in both the specific charge capacity and the capacity retention after 500 cycles to those in examples 1 to 5 in which the degree of curvature of the lattice and the amount of closed cells fall within their ranges. It is apparent that examples 1 to 5 have better sodium storage capacity and pore strength, and thus collapse of the structure does not easily occur during long-term charge and discharge, and have high cycle stability.
Various modifications and alterations of this application may be made by those skilled in the art without departing from the spirit and scope of this application. Thus, it is intended that the present application also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (9)

1. A hard carbon material for a negative electrode of a sodium ion battery is characterized in that the hard carbon material has lattice curvature0.03-0.15, And the closed pore volume is 0.04-0.5cm 3·g-1;
Wherein the method comprises the steps of The standard distance value corresponding to the position of the 6 th peak in the atomic pair distribution function spectrum in the interval of 0-10A is used for comparing with graphite; /(I)A distance value corresponding to the position of the 6 th peak in an atomic pair distribution function spectrum of the hard carbon material in a 0-10A interval; /(I)0.56 A for silver target wavelength;
the atomic pair distribution function spectrum is obtained through Fourier transformation of total scattering experimental data measured on a target material by an Ag target X-ray source total scattering experimental device;
the Fourier change formula of the atomic pair distribution function after data optimization is as follows:
introducing Lorch functions as M (Q) correction functions;
wherein the raw material of the hard carbon material is one or more of biomass derivative carbon sources or high molecular organic matters, and the biomass derivative carbon sources are one or more of cellulose, lignin and saccharides; and
The hard carbon material has a compacted density of 0.8-1.2g/cm 3.
2. The hard carbon material according to claim 1, wherein the hard carbon material is hard carbon particles having an average particle diameter of 2 to 50 μm and a carbon interlayer spacing d002 value of 0.35 to 0.40nm, the carbon interlayer spacing being obtained by an X-ray diffraction method using cukα rays as a radiation source and calculated based on the bragg equation.
3. The hard carbon material according to claim 1, wherein the hard carbon material has an average pore diameter of 0.5 to 5nm and a specific surface area of 0.5 to 20m 2·g-1; and/or the number of the groups of groups,
The hard carbon material has a burst strength of 14.5-22.8 kg-mm -2, as determined by the particle-particle crushing test described by ASTM D6175-3.
4. A method for preparing a hard carbon material for a negative electrode of a sodium ion battery according to claim 1, comprising the steps of:
Step (1): calcining a carbon source to obtain a hard carbon precursor;
Step (2): mixing and grinding the hard carbon precursor, a dispersing agent and an activating agent to obtain hard carbon precursor powder;
step (3): mixing the hard carbon precursor powder with a cross-linking agent and a template agent, and performing medium-temperature carbonization treatment on the obtained mixture in a protective atmosphere to obtain a first carbonized product;
Step (4): carrying out high-temperature carbonization treatment on the first carbonized product under a protective atmosphere or a mixed atmosphere of the protective atmosphere and an organic atmosphere to obtain a second carbonized product, namely obtaining the hard carbon material;
wherein the medium-temperature carbonization treatment temperature is 400-900 ℃ and the treatment time is 1-10h; the high-temperature carbonization treatment temperature is 900-1700 ℃, and the treatment time is 1-6h;
In the step (2), the dispersing agent comprises one or more of sodium carboxymethyl cellulose, cetyltrimethylammonium bromide, p-phenylenediamine, a silane coupling agent and tetracarboxylic dianhydride; the dispersant is used in an amount of 10 to 30 parts by weight, relative to 100 parts by weight of the hard carbon precursor; the activator comprises one or more of alkali metal hydroxide, metal halide and acid activator, wherein the alkali metal hydroxide comprises one or more of potassium hydroxide, sodium hydroxide, lithium hydroxide and cesium hydroxide, the metal halide comprises one or more of magnesium chloride, magnesium bromide, magnesium fluoride and calcium chloride, and the acid activator comprises one or more of phosphoric acid, sulfuric acid, hydrochloric acid and nitric acid; the activator is used in an amount of 5 to 20 parts by weight, relative to 100 parts by weight of the hard carbon precursor;
In the step (3), the template agent comprises one or more of ZnO, al 2O3 or MgO; compared with 100 weight parts of the hard carbon precursor, the template agent is used in an amount of 1-10 weight parts; the cross-linking agent comprises one or more of peroxide and a multifunctional compound, wherein the peroxide comprises one or more of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide, and the multifunctional compound comprises one or more of hexamethylenetetramine, melamine and polyaniline; the crosslinking agent is used in an amount of 10 to 40 parts by weight, relative to 100 parts by weight of the hard carbon precursor;
in the step (4), the organic matter atmosphere comprises one or more of ethanol, methanol, acetone, glycol, benzyl alcohol, dodecane, diformate, glycerol, ethyl benzoate and N-methyl pyrrolidone.
5. The method for producing a hard carbon material according to claim 4, further comprising the step (5):
and carrying out microwave or medium-frequency heating treatment on the second carbonized product in a protective atmosphere to obtain the hard carbon material.
6. The method for producing a hard carbon material according to claim 4, wherein:
in the step (1), the calcination temperature of the carbon source is 100-350 ℃ and the heat preservation time is 1-20h; and/or the number of the groups of groups,
In the step (2), the hard carbon precursor powder has a sieving particle size of 250-800 meshes; and/or the number of the groups of groups,
In the step (3), the template agent is a nanoscale sacrificial template agent, and the particle size range is 1-20 nm; and/or the number of the groups of groups,
In the step (3), the protective atmosphere is one or more selected from nitrogen atmosphere, helium atmosphere, neon atmosphere, argon atmosphere, krypton atmosphere, xenon atmosphere and radon atmosphere; and/or the number of the groups of groups,
In the step (4), the protective atmosphere is one or more selected from nitrogen atmosphere, helium atmosphere, neon atmosphere, argon atmosphere, krypton atmosphere, xenon atmosphere and radon atmosphere.
7. The method for producing hard carbon according to claim 5, wherein in the step (5), the frequency of the microwave or intermediate frequency heating treatment is 300kHz-100GHz, and the treatment time period is 30min-2h.
8. A sodium ion battery anode material, characterized in that the sodium ion battery anode material comprises the hard carbon material according to any one of claims 1 to 3, or the sodium ion battery anode material comprises the hard carbon material obtained by the production method according to any one of claims 4 to 7.
9. A sodium ion battery comprising the sodium ion battery anode material of claim 8.
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01230471A (en) * 1987-11-07 1989-09-13 Kobe Steel Ltd Carbon material and production thereof
CN1218304A (en) * 1998-10-30 1999-06-02 清华大学 Preparation of high activity anode material of lithium ion battery by controlled crystallization process
CN112397715A (en) * 2020-10-10 2021-02-23 北京化工大学 Hard carbon material, preparation method thereof and sodium ion battery
CN114436237A (en) * 2021-12-21 2022-05-06 华中科技大学 Hard carbon material and preparation method and application thereof
CN114524425A (en) * 2022-01-26 2022-05-24 广东海洋大学 Hard carbon material, preparation method thereof and application thereof in sodium-ion battery
CN116646519A (en) * 2023-05-04 2023-08-25 宁国富星新材料科技有限公司 Hard carbon negative electrode material, preparation method thereof and sodium ion battery
CN117293312A (en) * 2023-11-24 2023-12-26 深圳市贝特瑞新能源技术研究院有限公司 Hard carbon material, preparation method and application thereof, and sodium ion battery
CN117334811A (en) * 2022-06-23 2024-01-02 深圳市贝特瑞新能源技术研究院有限公司 Negative electrode material, preparation method thereof and sodium ion battery

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01230471A (en) * 1987-11-07 1989-09-13 Kobe Steel Ltd Carbon material and production thereof
CN1218304A (en) * 1998-10-30 1999-06-02 清华大学 Preparation of high activity anode material of lithium ion battery by controlled crystallization process
CN112397715A (en) * 2020-10-10 2021-02-23 北京化工大学 Hard carbon material, preparation method thereof and sodium ion battery
CN114436237A (en) * 2021-12-21 2022-05-06 华中科技大学 Hard carbon material and preparation method and application thereof
CN114524425A (en) * 2022-01-26 2022-05-24 广东海洋大学 Hard carbon material, preparation method thereof and application thereof in sodium-ion battery
CN117334811A (en) * 2022-06-23 2024-01-02 深圳市贝特瑞新能源技术研究院有限公司 Negative electrode material, preparation method thereof and sodium ion battery
CN116646519A (en) * 2023-05-04 2023-08-25 宁国富星新材料科技有限公司 Hard carbon negative electrode material, preparation method thereof and sodium ion battery
CN117293312A (en) * 2023-11-24 2023-12-26 深圳市贝特瑞新能源技术研究院有限公司 Hard carbon material, preparation method and application thereof, and sodium ion battery

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