CN112635719B - Battery cathode material, preparation method and application thereof, and lithium ion battery - Google Patents

Battery cathode material, preparation method and application thereof, and lithium ion battery Download PDF

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CN112635719B
CN112635719B CN201910953233.6A CN201910953233A CN112635719B CN 112635719 B CN112635719 B CN 112635719B CN 201910953233 A CN201910953233 A CN 201910953233A CN 112635719 B CN112635719 B CN 112635719B
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lithium
negative electrode
electrode material
battery
lithium salt
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CN112635719A (en
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孙赛
张丝雨
高焕新
张同宝
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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Priority to CN201910953233.6A priority Critical patent/CN112635719B/en
Application filed by China Petroleum and Chemical Corp, Sinopec Shanghai Research Institute of Petrochemical Technology filed Critical China Petroleum and Chemical Corp
Priority to EP20874397.1A priority patent/EP4044285A4/en
Priority to US17/754,393 priority patent/US20220393152A1/en
Priority to KR1020227015605A priority patent/KR20220078683A/en
Priority to PCT/CN2020/118704 priority patent/WO2021068793A1/en
Priority to AU2020363051A priority patent/AU2020363051A1/en
Priority to KR1020227015601A priority patent/KR20220078682A/en
Priority to US17/754,742 priority patent/US20230148348A1/en
Priority to CA3157355A priority patent/CA3157355A1/en
Priority to JP2022521414A priority patent/JP2022552485A/en
Priority to CA3155666A priority patent/CA3155666A1/en
Priority to BR112022005774A priority patent/BR112022005774A2/en
Priority to BR112022005422A priority patent/BR112022005422A2/en
Priority to AU2020363053A priority patent/AU2020363053A1/en
Priority to CN202080070424.9A priority patent/CN114467195A/en
Priority to JP2022521415A priority patent/JP2022552486A/en
Priority to PCT/CN2020/118720 priority patent/WO2021068796A1/en
Priority to EP20874623.0A priority patent/EP4044278A4/en
Priority to CN202080070420.0A priority patent/CN114467198A/en
Publication of CN112635719A publication Critical patent/CN112635719A/en
Publication of CN112635719B publication Critical patent/CN112635719B/en
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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
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
    • H01M4/602—Polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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

Abstract

The invention relates to the field of lithium ion batteries, and discloses a battery negative electrode material, a preparation method and application thereof, and a lithium ion battery. The preparation method of the battery negative electrode material comprises the following steps: mixing a silicon source, a phosphorus source and a solvent; (2) drying the material obtained by mixing in the step (1); (3) Mixing the solid matter obtained by drying with a polymer lithium salt. The battery cathode material provided by the invention can be applied to lithium ion batteries to improve the reversible charging capacity and the first coulombic efficiency of the lithium batteries.

Description

Battery cathode material, preparation method and application thereof, and lithium ion battery
Technical Field
The invention relates to the field of lithium ion batteries, in particular to a battery cathode material, a preparation method and application thereof and a lithium ion battery.
Background
At present, the new energy automobile mainly uses an electric automobile, and its power source is an energy storage battery, among them, a lithium ion battery has many advantages of no memory, low self-discharge rate, environmental protection, high specific energy, high specific power, etc., and is the most favored power battery by research and development institutions and automobile manufacturers. With the rapid development of new energy fields in recent years, the market demand for high-energy density lithium batteries is increasing. However, it is now commercializedThe lithium ion battery cathode material is mainly a carbon material, the theoretical specific capacity is only 372mAh/g, and the future requirement on the high-energy-density lithium battery cannot be realized at all. The theoretical specific capacity of the silicon-based negative electrode material is 4200 mA.h.g -1 The lithium ion battery is a cathode material with the highest gram capacity at present, and once the lithium ion battery is successfully applied, the energy density of the lithium ion battery can be obviously improved, so that the one-time charging endurance of 1000 kilometers becomes possible. However, the charge-discharge mechanism of silicon is different from that of graphite, and during the charge-discharge process, si is different from Li in the electrolyte + Solid Electrolyte Interphase (SEI) films are continuously generated at the interface, and the formation of the irreversible SEI consumes a large amount of Li extracted from an electrolyte and a positive electrode material, so that the initial coulombic efficiency of the silicon-based negative electrode material is only 65-85%, and the great capacity loss is caused. On the other hand, the conductivity and the lithium ion diffusion speed of silicon are lower than those of graphite, which limits the performance of silicon under the condition of large current and high power.
In order to solve the problems, scientific researchers adopt doping, nanocrystallization and other processes to improve the comprehensive electrical property of the silicon-based material. CN108172775A reports a phosphorus doped silicon-based negative electrode material, although the specific capacity of the phosphorus doped silicon-based negative electrode in the examples is 610.1mAh/g, the first effect is 91.7%, compared with the comparative example, the specific capacity and the first effect of the material are not significantly improved. CN101179126B reports a doped silicon-based negative electrode material for lithium ion batteries, which is doped with at least one element of boron, aluminum, gallium, antimony, and phosphorus, so that the coulombic efficiency of the material is improved, but the preparation process is complex, the cost is high, the large-scale preparation is not easy, and the comprehensive electrochemical performance still needs to be further improved. CN103400971A reports lithium silicate doped silicon carbon cathode material, si addition amount is 50%, li 2 SiO 3 When the addition amount is 35%, the specific capacity of the material is 1156.2mAh/g, the first effect is 88.2%, and the cycle stability and the coulombic efficiency of the material still need to be improved.
Therefore, the development and preparation process of the battery cathode material with simple process and high specific capacity becomes a problem to be solved urgently in the development process of the silicon-based material.
Disclosure of Invention
The invention aims to solve the problems of complex process, high cost and further improvement of the specific capacity of a negative electrode material in the prior art, and provides a battery negative electrode material, a preparation method of the battery negative electrode material, the battery negative electrode material prepared by the preparation method and a lithium ion battery. The battery cathode material provided by the invention can be applied to lithium ion batteries to improve the reversible charging capacity and the first coulombic efficiency of the lithium batteries.
In order to achieve the above object, a first aspect of the present invention provides a battery anode material including a polymer lithium salt, a phosphorus source, and an active component containing silicon element.
Preferably, the polymer lithium salt is selected from at least one of lithium polyacrylate, lithium polymethacrylate, lithium polymaleate, lithium polyfumarate, lithium carboxymethyl cellulose and lithium alginate.
Preferably, the phosphorus source is linked to the silicon element by a chemical bond, which is P (O) -O-Si.
Preferably, the phosphorus source is coated on the surface of the silicon element.
The second aspect of the present invention provides a method for preparing a battery negative electrode material, including:
(1) Mixing a silicon source, a phosphorus source and a solvent;
(2) Drying the material obtained by mixing in the step (1);
(3) Mixing the solid matter obtained by drying with a polymer lithium salt.
Preferably, the silicon source comprises silicon powder.
Preferably, the source of phosphorus is a polyphosphoric acid, preferably phytic acid.
The third aspect of the invention provides a battery negative electrode material prepared by the preparation method.
The invention also provides a method for preparing the battery cathode material.
The invention provides a lithium ion battery, which comprises the battery cathode material, the anode material, the diaphragm and the electrolyte.
Compared with the prior art, the battery cathode material provided by the invention has the following advantages:
(1) The negative electrode material contains polymer lithium salt capable of generating electrochemical reaction, can compensate lithium lost in the first charge-discharge process of silicon-based materials and the like, and can obviously improve the specific capacity of the negative electrode material;
(2) The cathode material contains a phosphorus source, and can enter silicon to form occupied doping in a high-temperature reaction, so that the conductivity of the silicon material is improved, and the comprehensive electrical property of the cathode material is favorably improved;
(3) The cathode material does not contain elemental lithium, is safe and stable, is convenient to store, has no special requirements on the use working condition, and has no corrosion to pole pieces, equipment and operators.
Drawings
FIG. 1 is a TEM photograph of negative electrode material S-1 obtained in example 1, in which A is a phosphorus source and B is silicon powder.
Fig. 2 is an X-ray photoelectron spectrum of the negative electrode material obtained in example 1.
FIG. 3 is a total reflection Fourier transform absorption Infrared Spectroscopy (ATR-FTIR) for polyacrylic acid and lithium polyacrylate, where C is the absorption curve for polyacrylic acid and D is the absorption curve for lithium polyacrylate.
FIG. 4 is a first charge-discharge curve of the negative electrode material S-1 obtained in example 1.
FIG. 5 is a first charge and discharge curve of the anode material D-1 obtained in comparative example 1.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In the present specification, the median diameter refers to a diameter corresponding to a cumulative particle size distribution percentage of 50%, and is generally used to indicate an average particle size of a powder.
The invention provides a battery negative electrode material, which comprises a polymer lithium salt, a phosphorus source and an active component, wherein the active component contains silicon.
According to the present invention, the polymeric lithium salt is preferably a salt of a compound having an organic acid functional group (preferably a carboxyl group) with a lithium-containing basic compound (preferably at least one selected from the group consisting of lithium hydroxide, lithium oxide and lithium carbonate). That is, it is preferable that the polymer lithium salt has a-C (O) -OLi group on the molecular chain. The group can be obtained by total reflection Fourier transform absorption infrared spectrum characterization.
Preferably, the polymer lithium salt is selected from at least one of lithium polyacrylate, lithium polymethacrylate, lithium polymaleate, lithium polyfumarate, lithium carboxymethyl cellulose and lithium alginate.
The molecular weight of the lithium salt is selected from a wide range, and the weight average molecular weight of the lithium salt is preferably 2000-5000000, more preferably 80000-240000.
According to the invention, the content of each component of the negative electrode material is selected in a wide range, and preferably, based on the total amount of the negative electrode material, the content of the polymer lithium salt is 1-15 wt%, the content of the phosphorus source is 10-60 wt%, and the content of the active component is 25-75 wt%; more preferably, the content of the polymer lithium salt is 3-15 wt%, the content of the phosphorus source is 14-45 wt%, and the content of the active component is 40-75 wt% based on the total amount of the negative electrode material.
According to the invention, the phosphorus source is preferably linked to the silicon element by a chemical bond, preferably the chemical bond is P (O) -O-Si. The preferred embodiment is more beneficial to improving the dispersibility of the silicon powder in the solvent and improving the coating uniformity of the surface of the silicon powder. The connection of the phosphorus source and the Si element through P (O) -O-Si can be characterized by an X-ray photoelectron spectrum.
Preferably, the phosphorus source is coated on the surface of the silicon element.
According to the invention, preferably, the source of phosphorus is a polyphosphoric acid, preferably phytic acid.
According to the anode material provided by the invention, preferably, the anode material further contains a conductive agent. The conductive agent is not particularly limited in the present invention, and preferably, the conductive agent is at least one selected from the group consisting of carbon nanotubes, acetylene black and conductive carbon black. Among them, the carbon nanotube, acetylene black and conductive carbon black are conventionally understood by those skilled in the art and are commercially available.
According to the present invention, the content of the conductive agent in the anode material is selected in a wide range, and preferably, the content of the conductive agent is 1 to 10% by weight, more preferably 1 to 6% by weight, based on the total amount of the anode material.
The second aspect of the present invention provides a method for preparing a battery anode material, including:
(1) Mixing a silicon source, a phosphorus source and a solvent;
(2) Drying the material obtained by mixing in the step (1);
(3) Mixing the solid matter obtained by drying with a polymer lithium salt.
According to the invention, preferably, the silicon source is silicon powder, and the median particle size of the silicon powder is 0.05-10 μm. The median particle size of 120nm is exemplified in the examples of the present invention, and the present invention is not limited thereto.
According to the invention, preferably, the source of phosphorus is a polyphosphoric acid, preferably phytic acid; among them, the phytic acid is a meaning conventionally understood by those skilled in the art, and is commercially available.
According to the present invention, the solvent may be an organic solvent conventionally used in the art, and is preferably at least one of toluene, N-dimethylformamide, N-dimethylacetamide, and N-methylpyrrolidone.
According to the present invention, the mixing in the step (1) is not particularly limited. Preferably, the mixing of step (1) comprises: the phosphorus source and the solvent are mixed first, and then the silicon source is added.
The solvent is added in a wide range, preferably, the solid content of the material obtained by mixing in step (1) is 5-40 wt%, preferably 5-30 wt%.
According to the invention, the adding amount of the phosphorus source is related to the using amount of the silicon source, and the mass ratio of the phosphorus source to the silicon source is preferably 0.1-2:1, for example 0.1: 1. 0.5: 1. 1:1. 1.5: 1. 2:1, and any two of these values in the range, preferably 0.5 to 1:1.
according to a specific embodiment of the present invention, the method further comprises isolating the product of step (1) before drying in step (2). The separation may be by separation methods conventional in the art, such as centrifugation.
The invention has wide selection range of drying conditions, and preferably, the drying temperature is 80-150 ℃ and the drying time is 1-10h.
According to the present invention, the kind of the polymer lithium salt is as described above, and the present invention is not described herein again.
The polymer lithium salt may be obtained commercially or may be prepared, and the present invention is not particularly limited thereto. For example, the lithium polyacrylate can be obtained by reacting polyacrylic acid and a lithium salt (preferably lithium hydroxide) in the presence of a solvent (e.g., water). The lithium polymethacrylate can be obtained by reacting polymethacrylic acid with a lithium salt (preferably lithium hydroxide) in the presence of a solvent (e.g., water). The lithium polymaleate may be obtained by reacting polymaleic acid with a lithium salt, preferably lithium hydroxide, in the presence of a solvent, for example, water. The lithium polyfumarate may be obtained by reacting polyfumarate with a lithium salt, preferably lithium hydroxide, in the presence of a solvent, for example, water. The lithium carboxymethyl cellulose may be obtained by reacting carboxymethyl cellulose and/or a salt thereof (e.g., sodium salt) with a lithium source (preferably lithium hydroxide and/or lithium oxide) in the presence of a solvent (e.g., water). The lithium alginate may be obtained by reacting alginic acid and/or a salt thereof (e.g. a sodium salt) with a lithium source, preferably lithium hydroxide and/or lithium oxide, in the presence of a solvent (e.g. water). The specific reaction process can be carried out according to the conventional reaction in the field, and the invention is not described in detail herein.
According to the present invention, the mixing manner of the solid substance and the polymer lithium salt in the step (3) is not particularly limited, and for example, the solid substance and the polymer lithium salt are mixed in the presence of the first solvent. As mentioned above, a solvent (e.g., water) is also used in the preparation of the lithium polymer salt. For convenience of operation, it is preferable to mix a slurry containing a polymer lithium salt (which may be obtained by the above-mentioned preparation process of the polymer lithium salt) and the solid substance. Preferably, the mixing is carried out under stirring conditions, the stirring time being 4-48h. Preferably, the first solvent is water.
According to the invention, the slurry containing the solid matter and the polymer lithium salt obtained in step (3) of the preparation method provided by the invention can be optionally dried to obtain the battery negative electrode material. When the slurry is not dried, the obtained slurry can be directly coated on a current collector for later use; when dried, the obtained battery anode material is more convenient to transport, and when in use, the battery anode material can be prepared into slurry with a suitable concentration by a person skilled in the art and coated. Either way, it is within the scope of the invention. For the sake of simplicity of operation, the slurry containing the solid substance and the lithium salt of the polymer obtained in step (3) is partially coated in the examples of the present invention, and the amount of the first solvent to be added in the present invention is selected from a wide range as long as the coating can be satisfied.
According to the invention, the addition amount of the solid substance is related to the amount of the polymer lithium salt, and preferably, the mass ratio of the solid substance obtained by drying to the polymer lithium salt is 1: (0.03-0.15), preferably 1: (0.08-0.13).
According to the present invention, preferably, the method further comprises the step of introducing a conductive agent. Preferably, the conductive agent is introduced in step (3).
According to a preferred embodiment of the present invention, the conductive agent is added to a slurry containing a solid substance and a lithium salt of a polymer, and then the stirring is performed.
According to the present invention, the kind of the conductive agent is as described above, and the present invention will not be described herein.
The selection range of the adding amount of the conductive agent is wide, and preferably, the mass ratio of the solid matter obtained by drying to the conductive agent is 1: (0.01-0.12), preferably 1: (0.06-0.1).
The third aspect of the invention provides a battery negative electrode material prepared by the preparation method. The structure and composition characteristics of the battery negative electrode material are as described above, and are not described in detail herein.
The invention also provides the application of the battery negative electrode material in a lithium ion battery. In the research process, the inventor of the invention finds that the energy density of a lithium battery can be improved by using the battery cathode material provided by the invention in the lithium ion battery.
The fifth aspect of the invention provides a lithium ion battery, which comprises the battery cathode material, the anode material, the diaphragm and the electrolyte.
The structure of the lithium ion battery provided according to the present invention may be well known to those skilled in the art, and generally, the separator is located between the positive electrode tab and the negative electrode tab. The positive plate contains the positive electrode material, and the negative plate contains the battery negative electrode material. The specific composition of the positive electrode material is not particularly limited in the present invention, and the positive electrode material may be a positive electrode material containing lithium element, which is conventionally used in the art.
According to the lithium ion battery provided by the invention, the separator can be selected from various separators used in the lithium ion battery known to those skilled in the art, such as a polypropylene microporous membrane, a polyethylene felt, a glass fiber felt or an ultrafine glass fiber paper.
According to the lithium ion battery provided by the invention, the electrolyte can be various conventional electrolytes, such as a nonaqueous electrolyte. The nonaqueous electrolytic solution is a solution of an electrolytic lithium salt in a nonaqueous solvent, and a conventional nonaqueous electrolytic solution known to those skilled in the art can be used. For example, the electrolyte may be selected from lithium hexafluorophosphate (LiPF) 6 ) Lithium perchlorate (LiClO) 4 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium hexafluoroarsenate (LiAsF) 6 ) And lithium hexafluorosilicate (LiSiF) 6 ) At least one of (1). The non-aqueous solvent can be selected from chain acid ester and cyclic acid ester mixed solution, wherein the chain acid ester can beIs at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl Methyl Carbonate (EMC), methyl Propyl Carbonate (MPC), and dipropyl carbonate (DPC). The cyclic acid ester may be at least one of Ethylene Carbonate (EC), propylene Carbonate (PC), and Vinylene Carbonate (VC).
The present invention will be described in detail below by way of examples. In the following examples and comparative examples, the morphology of the battery negative electrode material was characterized using a transmission electron microscope, specifically, a transmission electron microscope model JEM-2100, manufactured by japan electronics corporation, under test conditions: the accelerating voltage is 160KV, the sample is placed in a copper support net and then inserted into an electron microscope for observation, and the magnification of 80 ten thousand times is used for observation.
The battery cathode material is characterized by adopting an ESCALB 250Xi model X-ray photoelectron spectroscopy tester of ThermoFisher Scientific company in the United states, and the test conditions comprise: room temperature 25 deg.C, vacuum degree less than 5 × 10 -10 mba, working voltage 15KV, using Al K alpha as ray source.
Polyacrylic acid and lithium polyacrylate were characterized using a Bruker Alpha spectrometer from Bruker (Bruker) germany. And (3) testing conditions are as follows: the scanning range is from 350 to 4000cm -1 64 scan signals were collected per sample.
And testing the electrochemical performance of the assembled lithium ion battery by adopting a Wuhan blue battery testing system (CT 2001B). The test conditions included: the voltage range is 0.005V-3V, and the current range is 0.05A-2A. Each sample was assembled with 10 coin cells and the cell performance was tested at the same voltage and current and averaged.
In the following examples and comparative examples, the content of each component in the battery negative electrode material was calculated from the charged amount.
Phytic acid, polyacrylic acid, polymethacrylic acid, polymaleic acid, polyfumaric acid, carboxymethylcellulose and alginic acid are commercially available from the alatin reagent company.
Example 1
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
FIG. 1 is a TEM photograph of the phosphorus-containing silicon powder. As can be seen from the figure, the surface of the nano silicon powder (B) is coated with a layer of phosphorus-containing substance (A), and a core-shell structure is formed.
FIG. 2 is an X-ray photoelectron spectrum of phosphorus-containing silicon powder, which can also be obtained from the figure, wherein P element and Si element in the material are combined through P (O) -O-Si, and the chemical bond can ensure that a coating shell layer can exist stably, is not influenced by external environment, and lays a foundation for the material to exert excellent electrical property.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 240000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 3.4g of lithium hydroxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are dissolved to obtain the slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.55g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-1. The contents of the respective components of the lithium-containing negative electrode material S-1 are listed in table 1.
FIG. 3 shows the total reflection Fourier transform absorption IR spectrum of polyacrylic acid and lithium polyacrylate obtained in step 3), from which it can be seen that the C = O vibration peak in polyacrylic acid appears at 1700cm before reaction with lithium hydroxide -1 After lithiation the peak position was blue shifted to 1580cm -1 This indicates that C (O) -OH is converted to C (O) -OLi after the reaction.
5) And (3) uniformly coating 1g of the slurry of the lithium-containing negative electrode material S-1 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a lithium-containing negative electrode material S-1 pole piece.
Respectively taking the pole piece and the metal lithium piece obtained in the step 5) as a positive electrode and a negative electrode, and using 1mol/LLIPF6 solution as electrolyte (the ratio of ethylene carbonate to diethyl carbonate is 3:7 volume ratio is mixed as a solvent), a polypropylene microporous membrane is taken as a diaphragm, and the diaphragm is assembled into a CR2016 button battery to represent the electrical property of the lithium-containing negative electrode material S-1 in the embodiment.
FIG. 4 shows the first charge-discharge curve (test voltage range 0.05-3V, current 50 mA) of a button cell based on the lithium-containing negative electrode material S-1 described in example 1. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-1 in example 1 is 3000mAh g -1 The first coulombic efficiency was 86.9%.
Example 2
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.45g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 2000000 into 90g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 10%, adding 3.4g of lithium hydroxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain a slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.52g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-2. The contents of the respective components of the lithium-containing negative electrode material S-2 are listed in table 1.
5) And (3) uniformly coating 1g of the slurry containing the lithium-containing negative electrode material S-2 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece containing the lithium-containing negative electrode material S-2.
A battery was assembled and subjected to an electrical property test according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 2. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-2 in example 2 is 2720mAh g -1 The first coulombic efficiency was 85.2%.
Example 3
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.09g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 100000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 3.4g of lithium hydroxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are dissolved to obtain the slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.46g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-3. The contents of the respective components of the lithium-containing negative electrode material S-3 are listed in table 1.
5) And (3) uniformly coating 1.5g of the slurry of the lithium-containing negative electrode material S-3 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece of the lithium-containing negative electrode material S-3.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 3. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-3 in example 3 is 2978mAh g -1 The first coulombic efficiency was 86.1%.
Example 4
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of a N, N-dimethylformamide/phytic acid mixed solution (8.425g of N, N-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are similar to those of FIG. 1 and FIG. 2, respectively.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 200000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 1.2g of lithium hydroxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain the slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.42g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-4. The contents of the components of the lithium-containing negative electrode material S-3 are listed in table 1.
5) And (3) uniformly coating 1.5g of the slurry of the lithium-containing negative electrode material S-4 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece of the lithium-containing negative electrode material S-4.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 4. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-4 in example 4 is 2650mAh g -1 The first coulombic efficiency was 83.1%.
Example 5
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.9g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 200000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 0.35g of lithium hydroxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain the slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.34g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-5. The contents of the respective components of the lithium-containing negative electrode material S-5 are listed in table 1.
5) And (3) uniformly coating 1.2g of the slurry of the lithium-containing negative electrode material S-5 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10 hours to obtain a pole piece of the lithium-containing negative electrode material S-5.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 5. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-5 in example 5 is 1650mAh g -1 The first coulombic efficiency was 73.5%.
Example 6
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are similar to those of FIG. 1 and FIG. 2, respectively.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 200000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 2g of lithium oxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain a slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.27g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-6. The contents of the respective components of the lithium-containing negative electrode material S-6 are listed in table 1.
5) And (3) uniformly coating 1.2g of the slurry of the lithium-containing negative electrode material S-6 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece of the lithium-containing negative electrode material S-6.
A battery was assembled and subjected to an electrical property test in accordance with the method of example 1, except that lithium-containing negative electrode material S-1 was usedThe pole piece was replaced with the pole piece made in example 6. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-6 in example 6 is 3120mAh g -1 The first coulombic efficiency was 87.2%.
Example 7
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 200000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 0.3g of lithium oxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain the slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.21g, sequentially adding 4g of phosphorus-containing silicon powder and 0.05g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-7. The contents of the respective components of the lithium-containing negative electrode material S-7 are listed in table 1.
5) And (3) uniformly coating 1.2g of the slurry of the lithium-containing negative electrode material S-7 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece of the lithium-containing negative electrode material S-7.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 7. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-7 in example 7 is 1810 mAh.g -1 The first coulombic efficiency was 80.1%.
Example 8
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of polyacrylic acid with the weight-average molecular weight of 200000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 4.5g of lithium carbonate into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain the slurry containing lithium polyacrylate.
4) Taking the slurry with the lithium polyacrylate content of 0.18g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-8. The contents of the respective components of the lithium-containing negative electrode material S-8 are listed in table 1.
5) And (3) uniformly coating 1g of the slurry containing the lithium negative electrode material S-8 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10 hours to obtain a pole piece containing the lithium negative electrode material S-8.
A battery was assembled and subjected to an electrical property test according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 8. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-8 in example 8 is 2950mAh g -1 The first coulombic efficiency was 86.1%.
Example 9
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of alginic acid with the weight-average molecular weight of 120000 into 40g of deionized water to prepare an alginic acid solution with the mass fraction of 20%, adding 3.2g of lithium hydroxide into the alginic acid solution, and heating and stirring at 40 ℃ until all solids are dissolved to obtain the slurry containing the lithium alginate.
4) Taking the slurry with the content of the lithium alginate of 0.15g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-9. The contents of the respective components of the lithium-containing negative electrode material S-9 are listed in table 1.
5) And (3) uniformly coating 1g of the slurry containing the lithium negative material S-9 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece containing the lithium negative material S-9.
A battery was assembled and subjected to an electrical property test according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 9. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-9 in example 9 is 2760mAh g -1 The first coulombic efficiency was 83.5%.
Example 10
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of carboxymethyl cellulose with the weight-average molecular weight of 10000 into 40g of deionized water to prepare a carboxymethyl cellulose solution with the mass fraction of 20%, adding 2.5g of lithium hydroxide into the carboxymethyl cellulose acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain the slurry containing the lithium carboxymethyl cellulose.
4) Taking the slurry with the content of the lithium carboxymethyl cellulose of 0.13g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-10. The contents of the components of the lithium-containing negative electrode material S-10 are listed in table 1.
5) And (3) uniformly coating 1.5g of the slurry of the lithium-containing negative electrode material S-10 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece of the lithium-containing negative electrode material S-10.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 10. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-10 in example 10 is 2632mAh g -1 The first coulombic efficiency was 81.4%.
Example 11
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are similar to those of FIG. 1 and FIG. 2, respectively.
3) Adding 10g of polymethacrylic acid with the weight-average molecular weight of 240000 into 40g of deionized water to prepare a polymethacrylic acid solution with the mass fraction of 20%, adding 2.5g of lithium hydroxide into the polymethacrylic acid solution, and heating and stirring at 40 ℃ until all solids are dissolved to obtain the slurry containing the lithium polymethacrylate.
4) Taking the slurry with the content of the lithium polymethacrylate being 0.13g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-11. The contents of the components of the lithium-containing negative electrode material S-11 are listed in table 1.
5) And (3) uniformly coating 1.5g of the slurry of the lithium-containing negative electrode material S-11 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece of the lithium-containing negative electrode material S-11.
A battery was assembled and subjected to an electrical property test in accordance with the procedure of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 11. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-11 in example 11 is 2753mAh g -1 First time, theThe coulombic efficiency was 83.6%.
Example 12
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of an n, n-dimethylformamide/phytic acid mixed solution (8.425g of n, n-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of polymaleic acid with the weight-average molecular weight of 80000 into 40g of deionized water to prepare a polymaleic acid solution with the mass fraction of 20%, adding 2.5g of lithium hydroxide into the polymaleic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain the slurry containing the lithium polymaleate.
4) Taking the slurry with the content of 0.13g of the polymaleic acid lithium, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-12. The contents of the respective components of the lithium-containing negative electrode material S-12 are listed in table 1.
5) And (3) uniformly coating 1.5g of the slurry of the lithium-containing negative electrode material S-12 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10h to obtain a pole piece of the lithium-containing negative electrode material S-12.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 12. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-12 in example 12 is 2695mAh g -1 The first coulombic efficiency was 82.1%.
Example 13
1) 0.45g of silicon powder (D50 =120 nm) was added to 8.65g of a N, N-dimethylformamide/phytic acid mixed solution (8.425g of N, N-dimethylformamide and 0.225g of phytic acid), and stirred for 40min.
2) And after stirring, transferring the slurry into a 50mL centrifugal tube, centrifuging for 5min at the rotating speed of 5000rpm, collecting lower-layer solid, and drying for 4h at 100 ℃ to obtain the phosphorus-containing silicon powder.
The TEM image and the X-ray photoelectron spectrum of the phosphorus-containing silicon powder are respectively similar to those of the images in FIGS. 1 and 2.
3) Adding 10g of polyfumaric acid with the weight-average molecular weight of 120000 into 40g of deionized water to prepare a polyfumaric acid solution with the mass fraction of 20%, adding 2.5g of lithium hydroxide into the polyfumaric acid solution, and heating and stirring at 40 ℃ until all solids are dissolved to obtain the slurry containing lithium polyfumarate.
4) Taking the slurry with the lithium polyfumarate content of 0.13g, sequentially adding 4g of phosphorus-containing silicon powder and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material S-13. The contents of the respective components of the lithium-containing negative electrode material S-13 are listed in table 1.
5) And (3) uniformly coating 1.5g of the slurry of the lithium-containing negative electrode material S-13 obtained in the step 4) on a copper foil current collector, and drying at 120 ℃ for 10 hours to obtain a pole piece of the lithium-containing negative electrode material S-13.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in example 13. The test result shows that the reversible charge capacity of the lithium-containing negative electrode material S-13 of example 13 is 2710mAh g -1 The first coulombic efficiency was 82.5%.
Comparative example 1
A negative electrode material D-1 was obtained in the same manner as in example 1, except that in comparative example 1, step 3), 3.4g of lithium hydroxide was not added. The contents of the respective components of the anode material D-1 are shown in table 1.
A battery was assembled and subjected to an electrical property test according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in comparative example 1.
FIG. 5 is a first charge-discharge curve (test voltage range 0.05-3V, current 50 mA) of a coin cell based on the negative electrode material D-1 described in comparative example 1. As shown in the graph, the negative electrode material D-1 of comparative example 1 had a reversible charge capacity of 908mAh g -1 The first coulombic efficiency was 38.9%.
Comparative example 2
The method of example 1 was followed except that no phosphorus source was added during the preparation of the negative electrode material. Specifically, the method comprises the following steps:
adding 10g of polyacrylic acid with the weight-average molecular weight of 240000 into 40g of deionized water to prepare a polyacrylic acid solution with the mass fraction of 20%, adding 3.4g of lithium hydroxide into the polyacrylic acid solution, and heating and stirring at 40 ℃ until all solids are completely dissolved to obtain slurry containing lithium polyacrylate;
taking the slurry with the lithium polyacrylate content of 0.55g, sequentially adding 4g of silicon powder (D50 =120 nm) and 0.25g of conductive carbon black, and stirring for 2 hours to obtain the slurry of the lithium-containing negative electrode material D-2. The contents of the respective components of the lithium-containing negative electrode material D-2 are listed in table 1.
And (3) uniformly coating 1g of the slurry of the lithium-containing negative electrode material D-2 on a copper foil current collector, and drying at 120 ℃ for 10 hours to obtain a pole piece of the lithium-containing negative electrode material D-2.
A battery was assembled and tested for electrical properties according to the method of example 1, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece prepared in comparative example 2. The test result shows that the lithium-containing negative electrode material D-2 of comparative example 2 has a reversible charge capacity of 1650mAh g -1 The first coulombic efficiency was 83.5%.
TABLE 1
Figure BDA0002226415790000211
The embodiment and the result show that the negative electrode material provided by the invention can be used for the lithium ion battery, and the reversible charge capacity and the first coulombic efficiency of the battery can be improved.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (28)

1. A battery negative electrode material is composed of polymer lithium salt, a phosphorus source, an active component and a conductive agent, wherein the active component contains silicon; the phosphorus source is connected with silicon element through a chemical bond, and the chemical bond is P (O) -O-Si; based on the total amount of the negative electrode material, the content of polymer lithium salt is 3-15 wt%, the content of phosphorus source is 27.8-45 wt%, the content of active component is 40-62.6 wt%, and the content of conductive agent is 1-10 wt%; the phosphorus source wraps the surface of the silicon element, wherein the mass ratio of the total amount of the phosphorus source and the active component to the polymer lithium salt is 1: (0.03-0.15);
the phosphorus source is phytic acid;
the preparation method of the battery negative electrode material comprises the following steps:
(1) Mixing a silicon source, a phosphorus source and a solvent; the solvent is at least one selected from toluene, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone; the mass ratio of the phosphorus source to the silicon source is 0.5-1:1;
(2) Drying the material obtained by mixing in the step (1);
(3) And (3) mixing the solid matter obtained by drying with a polymer lithium salt, wherein in the step (3), the mass ratio of the solid matter obtained by drying to the polymer lithium salt is 1: (0.03-0.15);
the method further comprises introducing a conductive agent in step (3).
2. The negative electrode material of claim 1, wherein the weight average molecular weight of the polymer lithium salt is 2000-5000000.
3. The negative electrode material of claim 2, wherein the weight average molecular weight of the polymeric lithium salt is 80000-240000.
4. The negative electrode material of claim 1, wherein the polymer lithium salt has a-C (O) -OLi group on a molecular chain.
5. The negative electrode material of claim 4, wherein the polymeric lithium salt is selected from at least one of lithium polyacrylate, lithium polymaleate, lithium polyfumarate, lithium carboxymethyl cellulose, and lithium alginate.
6. The negative electrode material of claim 4, wherein the polymeric lithium salt is lithium polymethacrylate.
7. The negative electrode material of any of claims 1-6, wherein the conductive agent is selected from carbon nanotubes and/or conductive carbon black.
8. The anode material according to any one of claims 1 to 6, wherein the conductive agent is acetylene black.
9. A method of preparing the negative electrode material for a battery of any one of claims 1 to 8, comprising:
(1) Mixing a silicon source, a phosphorus source and a solvent; the solvent is at least one selected from toluene, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone; the mass ratio of the phosphorus source to the silicon source is 0.5-1:1;
(2) Drying the material obtained by mixing in the step (1);
(3) And (2) mixing the solid matter obtained by drying with a polymer lithium salt, wherein in the step (3), the mass ratio of the solid matter obtained by drying to the polymer lithium salt is 1: (0.03-0.15);
the method further comprises introducing a conductive agent in step (3).
10. The method of claim 9, wherein the silicon source comprises silicon powder.
11. The method of claim 9, wherein the mixing of step (1) comprises: the phosphorus source and solvent are mixed and then a silicon source is added.
12. The method as claimed in claim 9, wherein the solid content of the material mixed in step (1) is 5 to 40% by weight.
13. The preparation method according to claim 9, wherein in the step (3), the mass ratio of the solid substance obtained by drying to the polymer lithium salt is 1: (0.08-0.13).
14. The production method according to any one of claims 9 to 13, wherein the weight average molecular weight of the polymer lithium salt is 2000 to 5000000.
15. The preparation method of claim 14, wherein the weight average molecular weight of the polymer lithium salt is 80000-240000.
16. The production method according to any one of claims 9 to 13, wherein the polymer lithium salt has a-C (O) -OLi group in a molecular chain.
17. The production method according to claim 16, wherein the polymer lithium salt is selected from at least one of lithium polyacrylate, lithium polymaleate, lithium polyfumarate, lithium carboxymethyl cellulose, and lithium alginate.
18. The production method according to claim 16, wherein the polymer lithium salt is lithium polymethacrylate.
19. The production method according to any one of claims 9 to 13, wherein the mixing in step (3) is performed in the presence of water.
20. The production method according to any one of claims 9 to 13, wherein the conductive agent is selected from carbon nanotubes and/or conductive carbon black.
21. The production method according to any one of claims 9 to 13, wherein the conductive agent is acetylene black.
22. The production method according to any one of claims 9 to 13, wherein the mass ratio of the solid matter obtained by drying to the conductive agent is 1: (0.01-0.12).
23. The production method according to claim 22, wherein the mass ratio of the solid matter obtained by drying to the conductive agent is 1: (0.06-0.1).
24. The production method according to any one of claims 9 to 13, wherein the temperature of the drying in the step (2) is 100 to 150 ℃.
25. A battery negative electrode material produced by the production method according to any one of claims 9 to 24.
26. Use of the battery anode material of any of claims 1-8 and 25 in a lithium ion battery.
27. A lithium ion battery comprising the battery anode material of any one of claims 1-8 and 25, a cathode material, a separator, and an electrolyte.
28. The lithium ion battery of claim 27, wherein the lithium ion battery is a liquid lithium ion battery, a semi-solid lithium ion battery, or an all-solid lithium ion battery.
CN201910953233.6A 2019-10-09 2019-10-09 Battery cathode material, preparation method and application thereof, and lithium ion battery Active CN112635719B (en)

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CN201910953233.6A CN112635719B (en) 2019-10-09 2019-10-09 Battery cathode material, preparation method and application thereof, and lithium ion battery
EP20874623.0A EP4044278A4 (en) 2019-10-09 2020-09-29 Negative electrode material, preparation method therefor, and application thereof, and lithium ion battery comprising same
BR112022005774A BR112022005774A2 (en) 2019-10-09 2020-09-29 Negative electrode material, method of preparation therefor, and application thereof, and lithium-ion battery comprising the same
PCT/CN2020/118704 WO2021068793A1 (en) 2019-10-09 2020-09-29 Negative electrode material, preparation method therefor, and application thereof, and lithium ion battery comprising same
AU2020363051A AU2020363051A1 (en) 2019-10-09 2020-09-29 Negative electrode material, preparation method therefor, and application thereof, and lithium ion battery comprising same
KR1020227015601A KR20220078682A (en) 2019-10-09 2020-09-29 Anode material, manufacturing method and use thereof, and lithium ion battery comprising same
US17/754,742 US20230148348A1 (en) 2019-10-09 2020-09-29 Negative electrode material, preparation method therefor and application thereof, and lithium-ion battery
CA3157355A CA3157355A1 (en) 2019-10-09 2020-09-29 Negative electrode material, comprising phosphorus-containing coating layer preparation and method thereof and litium ion battery comprising the same ___________________________
JP2022521414A JP2022552485A (en) 2019-10-09 2020-09-29 Negative electrode material, manufacturing method thereof, application thereof, and lithium ion battery containing same
AU2020363053A AU2020363053A1 (en) 2019-10-09 2020-09-29 Negative electrode material, preparation method therefor and application thereof, and lithium-ion battery
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KR1020227015605A KR20220078683A (en) 2019-10-09 2020-09-29 Anode material, manufacturing method and use thereof, and lithium ion battery
CA3155666A CA3155666A1 (en) 2019-10-09 2020-09-29 Negative electrode material comprising intercalated lithium ions, preparation method therefor and application thereof, and lithium-ion battery
CN202080070424.9A CN114467195A (en) 2019-10-09 2020-09-29 Negative electrode material, preparation method and application thereof, and lithium ion battery containing negative electrode material
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US17/754,393 US20220393152A1 (en) 2019-10-09 2020-09-29 Negative Electrode Material, Preparation Method Therefor, and Application Thereof, and Lithium Ion Battery Comprising Same
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