Anode material, its preparation and use

Abstract

The present disclosure relates to a negative electrode material, its manufacturing method, and its use, which is related to the field of lithium battery materials. The manufacturing method of the negative electrode material includes lithiating a negative electrode raw material in a lithiating solution containing a Li-aromatic composition, the aromatic composition including an unsubstituted aromatic compound and a substituted aromatic compound, or the aromatic composition including at least two substituted aromatic compounds. The negative electrode material, its manufacturing method, and its use provided by the present disclosure can improve lithium insertion depth and lithium insertion efficiency, reduce irreversible capacity loss, and improve battery capacity.

Description

[Technical field]

[0001] <CROSS REFERENCE TO RELATED APPLICATIONS> This application claims priority to a Chinese patent application filed with the China Patent Office on February 20, 2021, bearing application number 202110193700.7 and entitled "Negative electrode material for lithium ion batteries and its pre-lithiation treatment method, lithium ion battery," the entire contents of which are incorporated herein by reference.

[0002] The present disclosure belongs to the technical field of battery materials, and the present disclosure relates to negative electrode materials, their manufacturing methods and uses. [Background technology]

[0003] Lithium-ion batteries have the advantages of large energy density, high power output, long cycle life, and less environmental pollution, and are therefore widely used in electric vehicles and consumer electronic products. In order to increase the energy density of batteries, the research and development of silicon anode materials has matured. However, silicon anode materials have a large volume expansion (>300%) during the process of lithium intercalation, and the silicon anode materials are pulverized and fall off the current collector during charging and discharging, resulting in the loss of electrical contact between the active material and the current collector, and the large initial irreversible capacity loss consumes a large amount of electrolyte and lithium ions released from the positive electrode material, resulting in a decrease in charge and discharge efficiency, a decrease in discharge specific capacity and stability, and a decrease in the energy density and cycle life of the battery. Pre-lithiation technology provides an effective way to solve the irreversible capacity loss and improve the coulombic efficiency.

[0004] Electrochemical pre-lithiation and direct contact short circuit methods are effective and simple means that can reduce the initial irreversible loss of high-capacity carbon materials, alloy negative electrodes, and conversion materials, and have the advantages of precisely controlling the amount of pre-lithiation and good stability. However, their strict environmental requirements, such as an oxygen-free, anhydrous, and dry environment, limit their widespread use.

[0005] Although it is possible to use pre-lithiated additives for the positive and negative electrodes, further improvements are expected in terms of compatibility (stability, gas generation, toxicity, etc.) with the electrode manufacturing process, electrolyte, binder, and battery assembly process.

[0006] On the other hand, chemical prelithiation technology has made significant progress in research in recent years. It is a simple and effective method to prepare positive and negative electrode materials with pre-intercalated lithium using chemical prelithiation technology. However, such materials are in an oxidized or reduced state and are therefore susceptible to the effects of air, humidity, etc. in room temperature environments, making large-scale application difficult.

[0007] The materials produced by the above methods have limited lithium insertion depth and low initial effect, which cannot meet the needs. Summary of the Invention

[0008] The present disclosure relates to The negative electrode raw material is lithiated with a lithiating solution containing a Li-aromatic composition, The aromatic composition includes an unsubstituted aromatic compound and a substituted aromatic compound, or the aromatic composition includes at least two substituted aromatic compounds.

[0009] In the above embodiment, the synergistic effect of various combinations of aromatic compounds having substituents, or the synergistic effect of aromatic compounds having substituents and unsubstituted aromatic compounds, is utilized to form a gradient path of lithium insertion potential difference by combining aromatic compounds having different potential differences, and the lithium source and the negative electrode raw material spontaneously and quickly carry out chemical lithium insertion in the organic solvent, thereby improving the lithium insertion depth and lithium insertion efficiency, reducing irreversible capacity loss, and improving the battery capacity.

[0010] In some embodiments, the aromatic compound comprises at least one of benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, pyrene, tetracene, and pyridine.

[0011] In some embodiments, the substituents of the substituted aromatic compound include at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen, an ester group, an amino group, a substituted carbonyl group, and an amide group.

[0012] In some embodiments, the alkyl group comprises at least one of a linear or branched alkyl group having 1 to 6 carbon atoms. Preferably, the alkyl group comprises at least one of a linear or branched alkyl group having 1 to 3 carbon atoms, and may include, for example, a methyl group (-CH3), an ethyl group (-CH2CH3), an n-propyl group (-CH2CH2CH3), and / or an isopropyl group (-CH(CH3)2).

[0013] In some embodiments, the alkoxy group may include at least one of a linear or branched alkoxy group having 1 to 4 carbon atoms. Preferably, the alkoxy group includes a methoxy group (-OCH3) and / or an ethoxy group (-OC2H5).

[0014] In some embodiments, the aryloxy group comprises a phenoxy group.

[0015] In some embodiments, the halogen comprises at least one of -F, -Cl, -Br, and -I.

[0016] In some embodiments, the ester group comprises at least one of an alkyl ester group and an aryl ester group. Preferably, the ester group comprises a -COOR1 or methyl carboxylate group, where R1 comprises at least one of a linear or branched alkyl group having 1 to 3 carbon atoms, a phenyl group, or a benzyl group.

[0017] In some embodiments, the amino group comprises at least one of -NH2, -R2NH2, -NHR3, and -NR4R5, where R2 is at least one selected from alkylene groups or substituted alkylene groups having 1 to 3 carbon atoms, for example, R2 may be -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH(CH3)-, -C(CH3)2-, -CH(CH3)CH2-, -CH2CH(CH3)-, etc., and R3, R4, and R5 are each independently at least one selected from linear or branched alkyl groups having 1 to 3 carbon atoms.

[0018] In some embodiments, the substituted carbonyl group includes -COR6, where R6 includes at least one of a linear or branched alkyl group having 1 to 6 carbon atoms, a phenyl group, or a substituted phenyl group. The type of the substituent of the substituted phenyl group may suitably refer to the type of the substituent of the substituted aromatic compound, and may be, for example, at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen atom, an ester group, an amino group, a substituted carbonyl group, and an amide group.

[0019] In some embodiments, the substituted aromatic compounds have one or more substituents, ie, they can be mono- or poly-substituted.

[0020] In some embodiments, when the aromatic composition contains an unsubstituted aromatic compound and a substituted aromatic compound, the aromatic composition contains 3 mol % to 97 mol % of the unsubstituted aromatic compound and 3 mol % to 97 mol % of the substituted aromatic compound.

[0021] In some embodiments, when the aromatic composition comprises unsubstituted and substituted aromatic compounds, the aromatic composition contains 10 mol % to 90 mol % alkyl-substituted aromatic compounds, 20 mol % to 80 mol % alkoxy-substituted aromatic compounds, and 5 mol % to 40 mol % halogen-substituted aromatic compounds.

[0022] In some embodiments, when the aromatic composition comprises at least two substituted aromatic compounds, the aromatic composition comprises: Contains 10 mol % to 80 mol % of alkyl-substituted aromatic compounds and 20 mol % to 90 mol % of alkoxy-substituted aromatic compounds; Contains 50 mol % to 95 mol % of an alkyl-substituted aromatic compound and 5 mol % to 50 mol % of a halogen-substituted aromatic compound, Contains 60 mol % to 95 mol % of an alkoxy-substituted aromatic compound and 5 mol % to 40 mol % of a halogen-substituted aromatic compound; Contains 10 mol % to 90 mol % of one type of alkyl-substituted aromatic compound and 10 mol % to 90 mol % of another type of alkyl-substituted aromatic compound, It contains 20 mol % to 50 mol % of an alkyl-substituted aromatic compound, 20 mol % to 50 mol % of a halogen-substituted aromatic compound, and 20 mol % to 50 mol % of a substituted carbonyl-substituted aromatic compound, Contains 10 mol % to 50 mol % of halogen-substituted aromatic compounds and 50 mol % to 90 mol % of carbonyl-substituted aromatic compounds, 20 mol % to 50 mol % of a substituted carbonyl-substituted aromatic compound, 20 mol % to 50 mol % of an alkoxy-substituted aromatic compound, and 20 mol % to 50 mol % of a halogen-substituted aromatic compound are included, or It contains 50 mol % to 95 mol % of an alkoxy substituted aromatic compound and 5 mol % to 50 mol % of a substituted carbonyl substituted aromatic compound.

[0023] In some embodiments, the aromatic composition comprises an unsubstituted aromatic compound and at least two substituted aromatic compounds, preferably including an alkyl-substituted aromatic compound and an amino-substituted aromatic compound.

[0024] In some embodiments, the aromatic composition comprises from 20 mol % to 50 mol % unsubstituted aromatic compounds, from 20 mol % to 50 mol % alkyl substituted aromatic compounds, and from 20 mol % to 50 mol % substituted carbonyl substituted aromatic compounds.

[0025] In some embodiments, the lithiation solution is a mixture of a predominantly organic solution of an aromatic composition and a lithium source.

[0026] In some embodiments, the organic solvent of the organic solution includes at least one of an ether-based solvent, a carbonate-based solvent, a benzene-based solvent, and a ketone-based solvent. Preferably, the ether-based solvent includes at least one of ethylene glycol dimethyl ether, tetrahydrofuran, propylene oxide, and diethyl ether, the carbonate-based solvent includes dimethyl carbonate, the benzene-based solvent includes at least one of benzene and toluene, and the ketone-based solvent includes at least one of acetone and methyl ethyl ketone.

[0027] In some embodiments, the concentration of the aromatic composition in the organic solution of the aromatic composition is 0.2 mol / L to 2 mol / L.

[0028] In some embodiments, the preparation of the organic solution of the aromatic composition includes dissolving the aromatic composition in an organic solvent. A stirring treatment may be performed during dissolution. Preferably, the stirring treatment is performed for 10 to 30 minutes.

[0029] In some embodiments, the lithium source comprises at least one of lithium metal and a lithium alloy having a lithium content of greater than 40%. Suitably, the lithium source may be mixed with the organic solution of the aromatic composition as a powder, sheet material, block material, or the like.

[0030] In some embodiments, the molar ratio of the lithium source, calculated as Li, to the aromatic composition is greater than 2.

[0031] In some embodiments, during the preparation of the lithium-based solution, the temperature of the mixing is 10° C. to 30° C., and the time of the mixing is 5 min to 10 min.

[0032] In some embodiments, the molar ratio of the Li-aromatic composition to the anode feedstock is (0.2-2):1. In some embodiments, the anode feedstock comprises at least one of a silicon-based material, a carbon-based material, and a silicon carbon composite. Preferably, the anode feedstock comprises silicon monoxide.

[0033] In some embodiments, the negative electrode material is added to the lithiation solution as a powder or sheet and subjected to the lithiation process. Preferably, the powder has a particle size smaller than 50 μm.

[0034] In some embodiments, the lithiation is carried out under stirring conditions. Preferably, the stirring method includes at least one of magnetic stirring, ultrasonic stirring, and mechanical stirring. Preferably, the stirring time may be 15 minutes to 60 minutes.

[0035] In some embodiments, the lithiation process is followed by a solid-liquid separation, and the solid is collected and washed to obtain the lithiation process negative electrode material. Preferably, the solid-liquid separation process includes filtration. Preferably, the washing is performed with the organic solvent.

[0036] In some embodiments, the method further comprises drying the lithiated negative electrode material to obtain a pre-lithiated negative electrode material. Preferably, the drying is performed under a protective gas. Preferably, the protective gas includes at least one of helium gas, neon gas, argon gas, krypton gas, and xenon gas. Preferably, the drying time is 15 min to 60 min.

[0037] In some embodiments, in the preparation of the lithiation solution, the lithiation process is carried out under a protective gas, for example, in a glove box at room temperature and pressure in a protective gas atmosphere.

[0038] The embodiment of the present application is The negative electrode raw material is lithiated with a lithiating solution containing a Li-aromatic composition, The aromatic composition includes at least two aromatic compounds having different potentials, and a method for producing a negative electrode material is provided.

[0039] In some embodiments, the aromatic compound has a potential relative to lithium in the range of 0 to 0.5 V vs Li / Li + It is.

[0040] In some embodiments, there is a potential gradient relative to lithium between the different aromatic compounds.

[0041] In some embodiments, the difference in the average potentials relative to lithium between the different aromatic compounds, ΔV vs Li / Li + However, 0<△V≦0.3V is satisfied.

[0042] In some embodiments, the difference in the average potentials relative to lithium between the different aromatic compounds, ΔV vs Li / Li + However, 0<△V≦0.1V is satisfied.

[0043] When the aromatic composition includes an unsubstituted aromatic compound and a substituted aromatic compound, the unsubstituted aromatic compound and the substituted aromatic compound have different potentials, and the difference in potential of the unsubstituted aromatic compound with respect to lithium is 0 to 0.5 V vs Li / Li + The potential difference between the substituted aromatic compounds and lithium is 0~0.5V vs Li / Li + There is a potential gradient between the Li-aromatic compound corresponding to the unsubstituted aromatic compound (i.e., the Li-unsubstituted aromatic compound) and the Li-aromatic compound corresponding to the substituted aromatic compound (i.e., the Li-substituted aromatic compound). The Li-unsubstituted aromatic compound and the Li-substituted aromatic compound each have a potential difference with respect to lithium, △V vs Li / Li + However, 0<△V≦0.3V is satisfied.

[0044] When the aromatic composition contains at least two kinds of substituted aromatic compounds, the aromatic composition contains two kinds of substituted aromatic compounds. One kind of substituted aromatic compound has a different potential from another kind of substituted aromatic compound, and the difference in potential of one kind of substituted aromatic compound with respect to lithium is 0~0.5V vs Li / Li + The potential difference between other substituted aromatic compounds and lithium is 0~0.5V vs Li / Li + There is a potential gradient between the Li-aromatic compound corresponding to one type of substituted aromatic compound (i.e. Li-one type of substituted aromatic compound) and the Li-aromatic compound corresponding to another type of substituted aromatic compound (i.e. Li-another substituted aromatic compound). Each of the Li-one type of substituted aromatic compound and the Li-another substituted aromatic compound has a potential difference with respect to lithium, △V vs Li / Li + However, 0<△V≦0.3V is satisfied.

[0045] The embodiment of the present application is adding a lithium source to a mixed solution containing an aromatic composition and an organic solvent to obtain a lithiated solution containing a Li-aromatic compound, the aromatic composition comprising at least two aromatic compounds each having a different branched chain, or comprising a branched aromatic compound and an unmodified aromatic compound; adding a powdered anode material to the lithiated solution and drying to obtain a pre-lithiated anode material.

[0046] In some embodiments, the unmodified aromatic compounds include at least one of benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, pyrene, and tetracene.

[0047] In some embodiments, the branched chain comprises at least one of an alkane-based branched chain, an ether-based branched chain, a halogen-based branched chain, an ester-based branched chain, an amine-based branched chain, and a benzene ring-containing branched chain.

[0048] In some embodiments, the branched chains comprise alkane-based branches, the alkane-based branches comprising at least one of -CH3, -C2H5, and -C3H7.

[0049] In some embodiments, the branches include ether-based branches, the ether-based branches including at least one of -OCH3, -OCH2CH3, and -OC6H5.

[0050] In some embodiments, the branches include halogen-based branches, the halogen-based branches including at least one of -Cl, -F, -Br, and -I.

[0051] In some embodiments, the branches include ester-based branches, the ester-based branches including at least one of benzyl ester-based branches and benzoate ester-based branches.

[0052] In some embodiments, the branches comprise amine-based branches, the amine-based branches comprising at least one of -NH2, -CH2NH2, -CH2CH2NH2, -CH(CH3)NH2, -N(CH3)2, -NHCH2CH3, -NHCH2CH2CH3, and -NHCOCH3.

[0053] In some embodiments, the aromatic composition comprises branched and unmodified aromatic compounds.

[0054] In some embodiments, the molar ratio of the branched aromatic compound in the aromatic composition is 3% to 97%.

[0055] In some embodiments, the molar ratio of the aromatic compound having an alkane-based branched chain in the aromatic composition is 10% to 90%.

[0056] In some embodiments, the aromatic composition has a molar ratio of the aromatic compound having an ether-based branched chain of 20% to 80%.

[0057] In some embodiments, the molar ratio of the aromatic compound having a halogen-based branched chain in the aromatic composition is 5% to 40%.

[0058] In some embodiments, the aromatic composition comprises at least two aromatic compounds, each having a different branched chain, and the combination of aromatic compounds having different branched chains comprises: 10 mol % to 80 mol % of an aromatic compound having an alkane branched chain and 20 mol % to 90 mol % of an aromatic compound having an ether branched chain; 60 mol % to 95 mol % of an aromatic compound having an alkane-based branched chain and 5 mol % to 40 mol % of an aromatic compound having a halogen-based branched chain, or It contains 60 mol % to 95 mol % of an aromatic compound having an ether-based branched chain and 5 mol % to 40 mol % of an aromatic compound having a halogen-based branched chain.

[0059] In some embodiments, the aromatic composition comprises at least two aromatic compounds, each having a different branching, and an unmodified aromatic compound.

[0060] In some embodiments, the aromatic composition comprises at least two aromatic compounds, each having a different branched chain, and an unmodified aromatic compound, and at least one aromatic compound has an alkane-based or amine-based branched chain.

[0061] In some embodiments, the organic solvent comprises at least one of dimethyl ether, dimethyl carbonate, tetrahydrofuran, carbonate esters, toluene, benzene, diethyl ether, propylene oxide, and ketone solvents.

[0062] In some embodiments, the concentration of the aromatic compound in the mixed solution is 0.2 mol / L to 2.0 mol / L.

[0063] In some embodiments, the lithium source comprises at least one of lithium metal, a lithium alloy having a lithium content greater than 40%.

[0064] In some embodiments, the molar ratio of elemental lithium in the lithium source to the aromatic composition is greater than 2.

[0065] In some embodiments, the dissolution time of the lithium source is 5 min to 10 min, and the dissolution temperature of the lithium source is 10°C to 30°C.

[0066] In some embodiments, the molar ratio of the Li-aromatic compound to the negative electrode powder material is (0.2-2):1.

[0067] In some embodiments, the anode powder material comprises at least one of a silicon-based material, a carbon-based material, and a silicon carbon composite.

[0068] In some embodiments, the particle size of the negative electrode powder material is less than 50 μm.

[0069] In some embodiments, the stirring regime comprises at least one of magnetic stirring, ultrasonic stirring, and mechanical stirring.

[0070] In some embodiments, the stirring time is from 15 minutes to 60 minutes.

[0071] In some embodiments, the drying is performed under a protective gas, the protective gas comprising at least one of helium gas, neon gas, argon gas, krypton gas, and xenon gas.

[0072] In some embodiments, the drying time is from 15 minutes to 60 minutes.

[0073] In some embodiments, the method includes adding a lithium source to a mixed solution containing an aromatic composition and an organic solvent to provide a lithiated solution containing Li-aromatic compounds, the aromatic composition comprising an alkane-based branched aromatic compound and a halogen-based branched aromatic compound; and adding silicon monoxide to the lithiated solution, stirring, filtering, washing with an organic solvent, filtering, and drying to provide a pre-lithiated silicon monoxide material.

[0074] The present disclosure also provides an anode material comprising nanosilicon, a silicon-oxygen-lithium-containing compound, and an aromatic composition, wherein the silicon-oxygen-lithium-containing compound comprises at least one of Li2Si2O5, Li2SiO3, and Li4SiO4, and the aromatic composition at least partially coats the nanosilicon and the silicon-oxygen-lithium-containing compound.

[0075] In some embodiments, the negative electrode material comprises a core and a layer comprising an aromatic composition.

[0076] In some embodiments, the core comprises nanosilicon and a silicon oxygen lithium containing compound.

[0077] In some embodiments, the nanosilicon is dispersed in the silicon oxygen lithium containing compound.

[0078] In some embodiments, the core is SiO x (wherein x satisfies 0.4≦x≦1.6).

[0079] In some embodiments, the aromatic composition comprises at least two aromatic compounds of different electrical potentials.

[0080] In some embodiments, the difference in the average potentials relative to lithium between the different aromatic compounds, ΔV vs Li / Li + However, 0<△V≦0.3V is satisfied.

[0081] In some embodiments, the median diameter of the negative electrode material is 4 μm to 8 μm.

[0082] In some embodiments, the specific surface area of ​​the negative electrode material is 1.5 m 2 / g~4.2m 2 / g.

[0083] In some embodiments, the negative electrode material has a pH value of 10 to 11.5.

[0084] In some embodiments, the negative electrode material further comprises a carbon coating layer, the carbon coating layer coating the core.

[0085] In some embodiments, the negative electrode material further comprises a carbon coating layer, the aromatic composition being distributed on the core surface, within the carbon coating layer channels, and on an exterior surface of the carbon coating layer.

[0086] In some embodiments, the coating amount of the aromatic composition in the negative electrode material is 0 wt % to 2 wt %.

[0087] The present disclosure also provides a negative electrode sheet including a current collector and a negative electrode layer provided on a surface of the current collector, the negative electrode layer including a negative electrode material obtained by any one of the above-mentioned methods for producing the negative electrode material or any one of the above-mentioned types of negative electrode materials.

[0088] The present disclosure also provides a lithium ion battery comprising any one of the negative electrode sheets described above.

[0089] In some embodiments, the lithium ion battery further comprises a positive electrode sheet, a separator, and a non-aqueous electrolyte. Effect of the Invention

[0090] Beneficial effects of the present disclosure include:

[0091] Since aromatic compounds have conjugated π bonds, they can form conjugated lithium compounds, and lithium ions can be inserted deep into the material due to the potential difference between the conjugated lithium compounds and the material. In this embodiment, a gradient path of lithium insertion potential difference is established by combining aromatic compounds with different potential differences, and the lithium source and the negative electrode raw material spontaneously and quickly perform chemical lithium insertion in an organic solvent, thereby improving the lithium insertion depth and lithium insertion efficiency, reducing irreversible capacity loss, and improving battery capacity. [Brief description of the drawings]

[0092] [Figure 1] FIG. 1 is a schematic diagram of a flow chart of a pre-lithiation method for a negative electrode material for a lithium-ion battery provided in an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0093] The following are preferred embodiments of the present invention. However, those skilled in the art may make some improvements or modifications to the present invention without departing from the principles of the present invention. These improvements or modifications are also considered to be within the scope of the present invention.

[0094] In order to improve the lithium insertion depth and lithium insertion efficiency, reduce the irreversible capacity loss, and improve the battery capacity, the embodiments of the present application include: The negative electrode raw material is lithiated with a lithiating solution containing a Li-aromatic composition, A method for making an anode material is provided, wherein the aromatic composition comprises an unsubstituted aromatic compound and a substituted aromatic compound, or the aromatic composition comprises at least two substituted aromatic compounds.

[0095] In this disclosure, the Li-aromatic composition is a Li-aromatic compound complex formed from a lithium source and an aromatic compound in the aromatic composition.

[0096] The aromatic composition contains at least two types of aromatic compounds, and at least one of the aromatic compounds contains a substituent.

[0097] Specifically, refer to FIG. 1, and the method includes steps S10 and S20.

[0098] Step S10, mixing an organic solution of an aromatic composition with a lithium source to form a lithiated solution, wherein the aromatic composition comprises an unsubstituted aromatic compound and a substituted aromatic compound, or the aromatic composition comprises at least two kinds of substituted aromatic compounds.

[0099] In step S20, the negative electrode raw material is lithiated in a lithiation solution and dried to obtain a pre-lithiated negative electrode material.

[0100] In this embodiment, the substituted aromatic composition is optimized, and the preliminary lithium reaction is changed to a solid-liquid reaction, so that the contact surface between the lithium source and the lithium insertion source is increased, different potential gradients are formed, and the bond strength and morphology between the π electron cloud and Li are changed, thereby improving the lithium insertion efficiency and lithium insertion depth. The aromatic composition is dissolved in an organic solvent system, and the conjugated compound formed from the aromatic compound and metallic lithium is dispersed in the organic solvent, and the electrochemical potential is between the potentials of metallic lithium and the negative electrode raw material (e.g., silicon monoxide). Due to the potential difference between the lithium conjugated compound and the negative electrode raw material, the lithium ions can be inserted deep inside the negative electrode raw material. Therefore, the combination of aromatic compounds with different potential differences establishes a gradient path of the lithium insertion potential difference, and the lithium source and the negative electrode raw material spontaneously and quickly perform chemical lithium insertion in the organic solvent, thereby effectively improving the lithium insertion depth and lithium insertion efficiency, reducing irreversible capacity loss, and improving battery capacity.

[0101] In some embodiments, the lithiation solution is a mixture of a predominantly organic solution of an aromatic composition and a lithium source.

[0102] In some embodiments, the aromatic compound comprises at least one of benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, pyrene, tetracene, and pyridine.

[0103] In some embodiments, the substituents of the substituted aromatic compound include at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen, an ester group, an amino group, a substituted carbonyl group, and an amide group. For example, the substituted aromatic compound can be, but is not limited to, dimethylbiphenyl, 2-methylbiphenyl, 2,6-dimethylpyridine, anisole, diphenyl ether, 4,4-difluorobenzophenone, 3-fluoroanisole, benzophenone, and the like.

[0104] In some embodiments, the alkyl group comprises at least one of a linear or branched alkyl group having 1 to 6 carbon atoms. Suitably, the alkyl group comprises at least one of a linear or branched alkyl group having 1 to 3 carbon atoms, and may include, for example, a methyl group (-CH3), an ethyl group (-CH2CH3), an n-propyl group (-CH2CH2CH3), and / or an isopropyl group (-CH(CH3)2).

[0105] In some embodiments, the alkoxy group comprises at least one of a linear or branched alkoxy group having 1 to 4 carbon atoms. Preferably, the alkoxy group comprises a methoxy group (-OCH3) and / or an ethoxy group (-OC2H5).

[0106] In some embodiments, the aryloxy group comprises a phenoxy group (-OPh).

[0107] In some embodiments, the halogens include at least one of -F, -Cl, -Br, and -I.

[0108] In some embodiments, the ester group comprises at least one of an alkyl ester group and an aryl ester group. Preferably, the ester group is -COOR1 or a methyl carboxylate group, where R1 comprises at least one of a linear or branched alkyl group having 1 to 3 carbon atoms, a phenyl group, or a benzyl group. Examples include, but are not limited to, HCOOCH2-, -COOCH3, and -COOCH(CH3)2.

[0109] In some embodiments, the amino group comprises at least one of -NH2, -R2NH2, -NHR3, and -NR4R5, where R2 is at least one selected from an alkylene group or substituted alkylene group having 1 to 3 carbon atoms, for example, R2 may be -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH(CH3)-, -C(CH3)2-, -CH(CH3)CH2-, -CH2CH(CH3)-, etc., and R3, R4, and R5 are each independently at least one selected from a linear or branched alkyl group having 1 to 3 carbon atoms.

[0110] In some embodiments, the substituted carbonyl group includes -COR6, where R6 includes at least one of a linear or branched alkyl group having 1 to 6 carbon atoms, a phenyl group, or a substituted phenyl group. The type of the substituent of the substituted phenyl group may suitably refer to the type of the substituent of the substituted aromatic compound described above, and may be, for example, at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen, an ester group, an amino group, a substituted carbonyl group, and an amide group.

[0111] The number of the substituents of the substituted aromatic compound is 1 or more, that is, it may be mono-substituted or poly-substituted. There is no limitation on the position of the substituents of the substituted aromatic compound. The number of the substituents of the substituted aromatic compound is not limited. For example, when the aromatic compound is benzene, the number of the substituents may be an integer of 1 to 6, such as 1, 2, 3, etc.; when the aromatic compound is biphenyl, the number of the substituents may be an integer of 1 to 10, such as 1, 2, 3, 4, 5, etc.; when the aromatic compound is terphenyl, the number of the substituents may be an integer of 1 to 14, such as 1, 2, 3, 4, 5, 6, 7, etc.; when the aromatic compound is naphthalene, the number of the substituents may be an integer of 1 to 8, such as 1, 2, 3, 4, etc.; when the aromatic compound is an anthracene, the number of the substituents may be an integer of 1 to 8, such as 1, 2, 3, 4, etc.; When the aromatic compound is a helical, the number of the substituents may be an integer from 1 to 10, such as 1, 2, 3, 4, 5, etc.; when the aromatic compound is a phenanthrene, the number of the substituents may be an integer from 1 to 10, such as 1, 2, 3, 4, 5, etc.; when the aromatic compound is a pyrene, the number of the substituents may be an integer from 1 to 10, such as 1, 2, 3, 4, 5, etc.; when the aromatic compound is a tetracene, the number of the substituents may be an integer from 1 to 12, such as 1, 2, 3, 4, 5, 6, etc.; when the aromatic compound is a pyridine, the number of the substituents may be an integer from 1 to 5, such as 1, 2, 3, etc.

[0112] In some embodiments, when the aromatic composition comprises an unsubstituted aromatic compound and a substituted aromatic compound, the aromatic composition comprises 3 mol % to 97 mol % of the unsubstituted aromatic compound and 3 mol % to 97 mol % of the substituted aromatic compound.

[0113] The potential of the non-substituted aromatic compound is too high, and the lithium insertion efficiency is low, so the initial effect of the negative electrode material after pre-lithiation is low. By combining the non-substituted aromatic compound and the substituted aromatic compound, the spatial distribution of the π electron density is adjusted, the gradient difference of the chemical potential is formed, and the lithium insertion passage is constructed, so that the lithium insertion depth is increased and the pre-lithiation efficiency is improved, and the initial effect of the pre-lithiation material is improved. In a specific embodiment, the lithium insertion depth can be increased by adjusting the type of the substituent to change the strength of the chemical reaction between the aromatic composition and lithium. In such pre-lithiation by solid-liquid chemical reaction, the amount of heat generated is small, the reaction is mild, it can be applied to powder or sheet, and the pre-lithiation effect is good.

[0114] By using a combination of substituted and unsubstituted aromatic compounds instead of a single substituted aromatic compound, the amount of metallic lithium used is reduced, production costs are reduced, and the pre-lithiation efficiency of the anode raw material (e.g., silicon monoxide) is improved.

[0115] Suitably, when the aromatic composition comprises an unsubstituted aromatic compound and a substituted aromatic compound, the substituted aromatic compound in the aromatic composition may be, but is not limited to, 3 mol%, 10 mol%, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, 70 mol%, 80 mol%, 90 mol%, 97 mol%, etc.

[0116] In some embodiments, when the aromatic composition comprises an unsubstituted aromatic compound and a substituted aromatic compound, in the aromatic composition: 10 mol % to 90 mol % of an alkyl-substituted aromatic compound and 10 mol % to 90 mol % of an unsubstituted aromatic compound; 20 mol % to 80 mol % of an alkoxy-substituted aromatic compound and 20 mol % to 80 mol % of an unsubstituted aromatic compound, or It contains 5 mol % to 40 mol % of a halogen-substituted aromatic compound and 60 mol % to 95 mol % of an unsubstituted aromatic compound.

[0117] Suitably, when the aromatic composition comprises an unsubstituted aromatic compound and an alkyl-substituted aromatic compound, the alkyl-substituted aromatic compound in the aromatic composition may be, but is not limited to, 10 mol%, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, 70 mol%, 80 mol%, 90 mol%, etc.

[0118] Suitably, when the aromatic composition comprises an unsubstituted aromatic compound and an alkoxy-substituted aromatic compound, the alkoxy-substituted aromatic compound in the aromatic composition may be, but is not limited to, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, 70 mol%, 80 mol%, etc.

[0119] Suitably, when the aromatic composition comprises an unsubstituted aromatic compound and a halogen-substituted aromatic compound, the halogen-substituted aromatic compound in the aromatic composition may be, but is not limited to, 5 mol%, 10 mol%, 15 mol%, 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, etc.

[0120] In some embodiments, when the aromatic composition comprises at least two substituted aromatic compounds, the aromatic composition may include, specifically: 10 mol % to 80 mol % of an alkyl-substituted aromatic compound and 20 mol % to 90 mol % of an alkoxy-substituted aromatic compound; 60 mol % to 95 mol % of an alkyl-substituted aromatic compound and 5 mol % to 40 mol % of a halogen-substituted aromatic compound; 60 mol % to 95 mol % of an alkoxy-substituted aromatic compound and 5 mol % to 40 mol % of a halogen-substituted aromatic compound, 10 mol % to 90 mol % of one alkyl-substituted aromatic compound and 10 mol % to 90 mol % of another alkyl-substituted aromatic compound; 20 mol % to 50 mol % of an alkyl-substituted aromatic compound, 20 mol % to 50 mol % of a halogen-substituted aromatic compound, and 20 mol % to 50 mol % of a substituted carbonyl-substituted aromatic compound, 10 mol % to 50 mol % of a halogen-substituted aromatic compound and 50 mol % to 90 mol % of a carbonyl-substituted aromatic compound, 20 mol % to 50 mol % of a substituted carbonyl-substituted aromatic compound, 20 mol % to 50 mol % of an alkoxy-substituted aromatic compound, and 20 mol % to 50 mol % of a halogen-substituted aromatic compound, or It contains 50 mol % to 95 mol % of an alkoxy substituted aromatic compound and 5 mol % to 50 mol % of a substituted carbonyl substituted aromatic compound.

[0121] Suitably, when the aromatic composition comprises an alkyl-substituted aromatic compound and an alkoxy-substituted aromatic compound, the alkyl-substituted aromatic compound in the aromatic composition may be, but is not limited to, 10 mol%, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, 70 mol%, 80 mol%, etc.

[0122] Suitably, when the aromatic composition comprises an alkyl-substituted aromatic compound and a halogen-substituted aromatic compound, the alkyl-substituted aromatic compound in the aromatic composition may be, but is not limited to, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, 95 mol%, etc.

[0123] Suitably, when the aromatic composition comprises an alkoxy-substituted aromatic compound and a halogen-substituted aromatic compound, the alkoxy-substituted aromatic compound in the aromatic composition may be, but is not limited to, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, 95 mol%, etc.

[0124] Suitably, when the aromatic composition comprises two different alkyl-substituted aromatic compounds, one of the alkyl-substituted aromatic compounds may be present in an amount of, but not limited to, 10 mol%, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, 70 mol%, 80 mol%, 90 mol%, etc. in the aromatic composition.

[0125] In some embodiments, the aromatic composition comprises an unsubstituted aromatic compound and at least two substituted aromatic compounds.

[0126] In some embodiments, the aromatic composition comprises an unsubstituted aromatic compound and at least two kinds of substituted aromatic compounds, and the substituted aromatic compounds comprise an alkyl-substituted aromatic compound and an amino-substituted aromatic compound. The more aromatic compounds are combined, the fewer restrictions there are on the molar combinations, and the more the potential gradient is subdivided, the more the electron orbitals are hybridized, and the more the energy levels are subdivided, and the more electrons transition, thus solving the lowering of the energy barrier, and improving the lithium insertion efficiency.

[0127] In some embodiments, the aromatic composition comprises 20 mol % to 50 mol % unsubstituted aromatic compounds, 20 mol % to 50 mol % alkyl substituted aromatic compounds, and 20 mol % to 50 mol % substituted carbonyl substituted aromatic compounds.

[0128] The molar percentage here refers to the molar ratio of a specific substituted aromatic compound to all aromatic compounds having different substituents. Of course, it may be a combination of an aromatic compound whose substituent is an alkyl group A and an aromatic compound whose substituent is an alkyl group B, or an aromatic compound whose substituent is an alkoxy group C and an aromatic compound whose substituent is an alkoxy group D. It is not limited to these.

[0129] Specifically, the potential of alkyl or alkoxy substituted aromatic compounds is lower than that of halogen substituted aromatic compounds. Therefore, the molar ratio of high potential halogen substituted aromatic compounds is set lower than that of alkoxy or alkyl substituted aromatic compounds. Here, the potential of aromatic compounds substituted with different alkoxy is varied in a large range, and the potential adjustment range is widened by combining alkoxy substituted aromatic compounds with low potential alkyl substituted aromatic compounds.

[0130] In addition, when a substituted aromatic compound contains two or more (including two) different types of substituents in its structure, it is classified according to the high potential substituent (halogen > carbonyl group > alkoxy group > alkyl group). For example, 3-fluoroanisole contains both halogen-F and -OCH3 in its structure and is considered to be a halogen-substituted aromatic compound, while 4,4-difluorobenzophenone contains both halogen-F and a substituted carbonyl group in its structure and is considered to be a halogen-substituted aromatic compound.

[0131] In addition, in the alkyl-substituted aromatic compounds, alkoxy-substituted aromatic compounds, halogen-substituted aromatic compounds, and aromatic compounds having multiple types of substitutions, the electric potential and potential difference with respect to lithium varies depending on the difference in the substituents. Based on this, a potential gradient and a lithium insertion path are established, which is advantageous for improving the lithium insertion efficiency.

[0132] In this embodiment, by combining an aromatic hydrocarbon compound having a substituent such as a halogen, an alkyl group, an alkoxy group, an ester group, or an amino group, the π-conjugated electron distribution can be changed and the lithium complex structure and position can be influenced to construct a chemical lithium insertion path, and the reaction of metallic lithium with the substituent, for example, the reaction of lithium with a hydroxyl group or a carboxyl group to generate hydrogen gas, can be prevented.

[0133] The present manufacturing method will now be described in detail.

[0134] Step S10, adding a lithium source to the organic solution of the aromatic composition to form a lithiated solution containing a Li-aromatic compound complex, the aromatic composition comprising an unsubstituted aromatic compound and a substituted aromatic compound, or the aromatic composition comprising at least two kinds of substituted aromatic compounds.

[0135] In a particular embodiment, the organic solvent of the organic solution includes at least one of an ether-based solvent, a carbonate-based solvent, a benzene-based solvent, and a ketone-based solvent. Preferably, the ether-based solvent includes at least one of ethylene glycol dimethyl ether, tetrahydrofuran, propylene oxide, and diethyl ether, the carbonate-based solvent includes dimethyl carbonate, the benzene-based solvent includes at least one of benzene and toluene, and the ketone-based solvent includes at least one of acetone and methyl ethyl ketone.

[0136] The preparation of an organic solution of an aromatic composition includes a step of dissolving the aromatic composition in an organic solvent. Stirring may be performed during dissolution, thereby improving the homogeneity of the solution, and the stirring method includes at least one of magnetic stirring, ultrasonic stirring, and mechanical stirring. Preferably, the stirring time is 10 min to 30 min.

[0137] In the organic solution of the aromatic composition, the concentration of the aromatic composition is 0.2 mol / L to 2 mol / L, and specifically may be 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, 1.2 mol / L, 1.5 mol / L or 2 mol / L, but is not limited to the numerical values ​​described above, and other numerical values ​​not described above may also be applied as long as they are within this numerical range.

[0138] It can be understood that, compared with single-component aromatic compounds, in order to improve the efficiency of prelithiation, the concentration of aromatic compounds in the prelithiation solution is required to be high, and the consumption of aromatic compounds is large; on the other hand, by utilizing the blending ratio of the aromatic composition of the present application, the concentration of aromatic compounds can be effectively reduced, the loss of aromatic compounds in the prelithiation process of materials can be reduced, and the cost of prelithiation can be reduced.

[0139] When a lithium source is added to an organic solution, a two-step reaction occurs. First, the metallic lithium source (solid phase) reacts with the aromatic compound (liquid phase) in the organic solution to form a metal complex (Li-aromatic compound complex), and metallic Li is dissolved in the organic solvent to become a liquid lithium source. Second, the aromatic compound (Li-aromatic compound complex) after lithium insertion has different substituents, so that the Li-aromatic compound complex has multiple potential gradients, which effectively reduces the difficulty of Li migration and maintains the concentration of lithium near the interface during the prelithiation SiO reaction, thereby improving the depth and efficiency of lithium insertion.

[0140] In certain embodiments, the lithium source comprises at least one of lithium metal and a lithium alloy having a lithium content of greater than 40%. Suitably, the lithium source may be mixed with the organic solution of the aromatic composition as a powder, sheet material, block material, or the like.

[0141] The molar ratio of the lithium source (in terms of Li) to the aromatic composition is 2 or more, and may be 4 or more, specifically the molar ratio may be 4, 5, 6, 7, etc. It can be understood that a molar ratio of the lithium source to the aromatic composition of 4 or more ensures that the lithium source is in excess, and the metal complex (Li-aromatic compound complex) is quickly saturated in the lithiation solution, so that the material to be prelithiated can achieve the desired initial effect, and is fully prelithiated and efficient.

[0142] The lithium source is dissolved in an organic solution. In a specific embodiment, the dissolution time of the lithium source may be 5 min to 10 min, specifically, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc., and the dissolution temperature of the lithium source may be room temperature, 10°C to 30°C, specifically, 10°C, 15°C, 20°C, 25°C, 30°C, etc., but is not limited to the values ​​described above, and other values ​​not described may also be applied as long as they are within the range of these values.

[0143] Within the range of the dissolution temperature, the organic solvent and the organic compound are in a mixed liquid phase.

[0144] Optionally, after the lithium source is added to the organic solution, it may be appropriately stirred, so that the lithium source and the organic solution are more uniformly mixed, and the added negative electrode raw material is more uniformly subjected to the surface pre-lithiation treatment.

[0145] Step S20, the negative electrode raw material is added to a lithiated solution and dried to obtain a pre-lithiated negative electrode material.

[0146] It can be understood that the inclusion of Li-aromatic compound complex in the liquid phase lithiation solution maximizes the reaction interface of the anode raw material, increases the reaction area, reduces the transport resistance of lithium ions, and promotes the transport of Li during the lithiation reaction. + is released from the aromatic compound and enters the powder material to carry out an oxidation-reduction reaction, and the Li-aromatic compound complex combined with different potential differences controls the efficiency of the preliminary lithium reaction of the negative electrode raw material, and lithium is inserted deep inside.

[0147] In a particular embodiment, the negative electrode raw material includes at least one of silicon-based materials, carbon-based materials, and silicon carbon composites. Specifically, the silicon-based material may be specifically silicon oxide, silicon element, or silicon monoxide, the carbon-based material may be specifically graphite, and the silicon carbon composite may be specifically SiO+C, Si+C, etc. Specifically, when the negative electrode raw material is SiO+C, after the Li-aromatic compound complex is impregnated into the carbon layer, the lithium source undergoes a lithium insertion reaction, and a part of the aromatic compound is deposited on the surface of the core silicon particle, forming an aromatic compound deposition layer in the micropore channel in the carbon layer and on the outer surface of the carbon layer, and an organic polymer crystal layer is formed in the channel when the solvent is evaporated. When the organic polymer crystal layer is formed, a large amount of conjugated Li source is enclosed. Thus, during the formation, these deposited organic lithium compounds become part of the SEI layer, reducing the consumption of other active lithium, avoiding the loss of the initial effect during the formation, and improving efficiency.

[0148] In some other embodiments, the anode feedstock is added to the lithiation solution, stirred, filtered, washed with an organic solvent, filtered, and dried to obtain a pre-lithiated anode material. Preferably, silicon monoxide is added to the lithiation solution, stirred, filtered, washed with an organic solvent, filtered, and dried to obtain a pre-lithiated silicon monoxide material.

[0149] When the negative electrode raw material is SiO, lithium is inserted deeper and more, and a dense organic layer is formed on its surface. Later, when the carbon layer is coated, this part of the organic layer is carbonized by high temperature, and a carbon layer is formed with special functional groups and doping elements distributed inside, and these doping elements achieve atomic level dispersion, which improves the conductivity of the carbon layer.

[0150] The molar ratio of the lithium source to the negative electrode raw material may be 2 or more, specifically 2, 3, 4, 5, 6, 7, etc. It can be understood that the molar ratio of the lithium source to the negative electrode raw material is 2 or more, which ensures that the lithium source is in excess, so that the metal complex (Li-aromatic compound complex) can be quickly saturated in the lithiation solution, so that the negative electrode material to be prelithiated can achieve the desired initial effect, be fully prelithiated, and improve the efficiency.

[0151] In some embodiments, the negative electrode raw material is added as a powder or sheet to the lithiation solution to perform the lithiation process. Preferably, the particle size of the powder is smaller than 50 μm, specifically, it may be 1 nm, 3 nm, 5 nm, 10 nm, 50 nm, 0.1 μm, 1 μm, 10 μm, 20 μm, 30 μm, or 40 μm, but is not limited to the numerical values ​​described, and other numerical values ​​not described may be applied as long as they are within the numerical range. The larger the particle size, the smaller the specific surface area and the lower the lithium insertion efficiency. In addition to ensuring a predetermined lithium insertion efficiency, the blending method of the aromatic composition provided in the present application is used to widen the appropriate range of the powder particle size, and the smaller the median diameter of the negative electrode material, the more preferable, but considering the process cost, the median diameter of the negative electrode material is preferably 1 nm to 10 nm.

[0152] The molar ratio of the Li-aromatic complex to the negative electrode raw material can be (0.2-2):1, specifically 0.2:1, 0.4:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1, etc., thereby achieving a high efficiency pre-lithiation process at a low rate. At a low concentration ratio, for example, when the molar ratio of the Li-aromatic complex to the negative electrode raw material is 0.46, the initial effect of the negative electrode material after pre-lithiation reaches more than 90% in a short time (30 min), thereby obviously improving the pre-lithiation efficiency of the negative electrode raw material.

[0153] In some embodiments, the negative electrode raw material is added to the lithium solution and stirred, and the stirring method includes at least one of magnetic stirring, ultrasonic stirring and mechanical stirring. The stirring time may be 15min to 60min, specifically, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, etc., and is not limited to the numerical values ​​described, and other numerical values ​​not described can be applied as long as they are within the numerical range. In a specific embodiment, an appropriate stirring reaction time may be set according to the blending ratio of the aromatic composition, and generally, the longer the stirring time, the more sufficiently the reaction is carried out, which is advantageous for reaching the limit of the pre-lithiation amount achieved by the composition of the aromatic composition and obtaining the desired initial effect for the material.

[0154] After stirring, the mixture is filtered and washed with an organic solvent, and the organic solvent used for washing may include at least one of the organic solvents used when preparing the organic solution.

[0155] The drying is carried out under a protective gas, which includes at least one of helium gas, neon gas, argon gas, krypton gas, and xenon gas.

[0156] The drying time may be 15 min to 60 min, specifically, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc. The drying process is advantageous for volatilizing the solvent on the surface of the material, and the drying time may be controlled within the above range in consideration of the volatilization rate of the solvent, which is advantageous for the efficiency of production.

[0157] Optionally, natural drying is performed in a glove box at room temperature and pressure under argon gas protection, where the O2 content in the glove box is less than 0.1 ppm and the H2O content is less than 0.01 ppm. Alternatively, the powder material is purged with dry argon gas for 10 min to 30 min to completely volatilize the organic solvent adhering to the surface of the material, and a dried pre-lithiated powder is obtained.

[0158] The embodiment of the present application is The negative electrode raw material is lithiated with a lithiating solution containing a Li-aromatic composition, A method for producing a negative electrode material is provided, the aromatic composition comprising at least two aromatic compounds having different electrical potentials.

[0159] In some embodiments, the range of potential of the aromatic compound with respect to lithium is 0 to 0.5 V vs Li / Li + The potentials of aromatics against lithium were tested using a 4×4×4 bulk lithium model as the reference lithium and a 9×9×9 distribution of the Brillouin zone K-points. The aromatics establish a gradient pathway of lithium insertion potential difference, allowing for deeper insertion of lithium while improving the prelithiation efficiency and enhancing the priming effect of the material.

[0160] In some embodiments, there is a potential gradient relative to lithium between the different aromatic compounds.

[0161] In some embodiments, the difference in the average potentials relative to lithium between different aromatic compounds, ΔV vs Li / Li + However, 0<△V≦0.3V is satisfied.

[0162] In some embodiments, the difference in the average potentials relative to lithium between different aromatic compounds, ΔV vs Li / Li + However, 0<△V≦0.1V is satisfied.

[0163] An embodiment of the present disclosure also provides an anode material comprising nanosilicon, a silicon-oxygen-lithium-containing compound, and an aromatic composition, wherein the silicon-oxygen-lithium-containing compound comprises at least one of Li2Si2O5, Li2SiO3, and Li4SiO4, and the aromatic composition at least partially coats the nanosilicon and the silicon-oxygen-lithium-containing compound.

[0164] In the above embodiment, the negative electrode raw material is subjected to a pre-lithiation treatment, in which more lithium ions are inserted into the silicon oxide negative electrode raw material, thus improving the lithium insertion depth and lithium insertion efficiency; during charging and discharging, the lithium ions are released from the aromatic compound and enter the silicon oxide material, causing an oxidation-reduction reaction to replace the oxygen in the silicon oxide negative electrode raw material, and forming an alkaline residue on the surface of the silicon oxide material, thereby improving the processability of the material in an aqueous system, reducing the irreversible capacity loss, and improving the battery capacity.

[0165] In some embodiments, the negative electrode material includes a core and a layer comprising an aromatic composition.

[0166] In some embodiments, the core comprises nanosilicon and a silicon oxygen lithium containing compound.

[0167] In some embodiments, the nanosilicon is dispersed in a silicon oxygen lithium containing compound.

[0168] In some embodiments, the core is SiO x (wherein x satisfies 0.4≦x≦1.6).

[0169] In some embodiments, the aromatic composition comprises at least two aromatic compounds of different electrical potentials.

[0170] In some embodiments, the difference in the average potentials relative to lithium between different aromatic compounds, ΔV vs Li / Li + satisfies 0<ΔV≦0.3V, and specifically may be, but is not limited to, 0.05V, 0.1V, 0.15V, 0.2V, 0.25V, 0.3V, etc.

[0171] In some embodiments, the median diameter of the negative electrode material may be 4 μm to 8 μm, specifically, but not limited to, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, etc. Controlling the median diameter of the negative electrode material within the above range is advantageous for improving the cycle performance of the negative electrode material.

[0172] In some embodiments, the specific surface area of ​​the negative electrode material is 1.5 m 2 / g~4.2m 2 / g, specifically, 1.5m 2 / g, 1.8m 2 / g, 2m 2 / g, 2.5m 2 / g, 3m 2 / g, 3.5m 2 / g, 4m 2 / g, 4.2m 2 / g, etc., but are not limited thereto. When the specific surface area of ​​the negative electrode material is controlled within the above range, it is advantageous for improving the cycle performance of the negative electrode material.

[0173] In some embodiments, the pH value of the negative electrode material may be 10 to 11.5, specifically 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.8, 11, 11.2, 11.5, etc. Understandably, this keeps the material less alkaline, improves the processability of the material in aqueous systems, and enhances the initial effectiveness of the negative electrode material.

[0174] In some embodiments, the negative electrode material further comprises a carbon coating layer.

[0175] In some embodiments, the negative electrode material further comprises a carbon coating layer, the carbon coating layer coating the core.

[0176] In some embodiments, the negative electrode material further comprises a carbon coating layer, with the aromatic composition distributed on the core surface, within the carbon coating layer channels, and on an outer surface of the carbon coating layer.

[0177] In some embodiments, the amount of the aromatic compound coated in the negative electrode material for lithium-ion batteries may be 0 wt% to 2 wt%, specifically, but is not limited to, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.7 wt%, 1 wt%, 1.2 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%, 2 wt%, etc.

[0178] An embodiment of the present disclosure also provides a negative electrode sheet including a current collector and a negative electrode layer provided on a surface of the current collector, the negative electrode layer including a negative electrode material obtained by any one of the above methods for producing a negative electrode material or any one of the above negative electrode materials for lithium ion batteries.

[0179] An embodiment of the present disclosure also provides a lithium ion battery including any one of the negative electrode sheets described above.

[0180] In some embodiments, the lithium ion battery further comprises a positive electrode sheet, a separator, and a non-aqueous electrolyte. EXAMPLES

[0181] The present application will be further described below by way of a number of examples, in which the present application is not limited to the following specific examples, and appropriate modifications may be made within the scope of the patent.

[0182] Example 1 This embodiment is a method for pre-lithiating a negative electrode material for a lithium-ion battery, comprising: 1) mixing benzophenone (BP), dimethylbiphenyl (4,4-DMBP), and 4,4-difluorobenzophenone (4,4-DFBP) in a molar ratio of 1:1:1 to obtain an aromatic composition, dissolving 0.1 mol of the aromatic composition in 200 mL of ethylene glycol dimethyl ether (DME), and treating with magnetic stirring for 30 min to obtain an organic solution of the aromatic composition; Add 0.45 mol of lithium pieces with a lithium content of more than 99.5% to the organic solution and leave it for 10 minutes to fully dissolve the lithium to obtain a lithium-doped solution. The difference in the average potential of the different aromatic compounds with respect to lithium is 0.071 V vs Li / Li + Step 2) 2) adding 10 g of SiO powder (0.22 mol) to 200 mL of lithiation solution, treating with magnetic stirring for 30 min (experimental group 1) and 60 min (experimental group 2), suction filtering, washing with absolute ethanol three times, filtering, and then drying by natural evaporation for 30 min in a glove box to obtain pre-lithiated SiO powders, which are designated as S1 and S101. The negative electrode material produced in this example had a core and a layer made of an aromatic composition, the layer made of the aromatic composition at least partially coated the core, the core contained Si, SiOx and lithium silicate material, the layer made of the aromatic composition contained BP, 4,4-DMBP, and 4,4-DFBP, and the coating amount of the aromatic composition in the negative electrode material was 0.5 wt%. The test method for the potential of each aromatic compound against lithium is as follows. A 4×4×4 bulk lithium model is used as the reference lithium, where the K-point distribution of the Brillouin zone is set to 9×9×9. For the potential against the intrinsic lithium of aromatic compounds, E=-△G / n is obtained by the following equation, where △G is the reaction energy (unit: eV) of the lithiation reaction of aromatic compounds, n is the number of electrons transferred in the lithiation reaction, and E is the potential against the intrinsic lithium. All values ​​are from the open source software QUANTUM-ESPRESSO, and the above software is a density functional calculation software based on the plane wave unit. For aromatic compounds and their lithiation products, calculations are performed by a single molecule model. The PBE / GGA method is used to estimate the potential, and the Gamma point is used to perform the energy calculation. Here, the convergence threshold of the model is below 1.0E~5 eV / cell, and the convergence threshold of the intermolecular interaction force is 0.02eV / A. 3 In the calculation, the effect of electron spin must be taken into account, and finally, the weak interaction energy between atoms (molecules) is simulated by the DFT-D3(0) method. Meanwhile, the average potential difference with respect to lithium is the potential difference with respect to the intrinsic lithium of the aromatic compound.

[0183] Example 2 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP), dimethylbiphenyl (4,4-DMBP) and 4,4-difluorobenzophenone (4,4-DFBP) are mixed in a molar ratio of 1:2:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S2, where the average potential difference versus lithium between the different aromatic compounds was 0.076 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained BP, 4,4-DMBP, and 4,4-DFBP, and the coating amount of the aromatic composition in the negative electrode material was 0.3 wt %.

[0184] Example 3 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that dimethylbiphenyl (4,4-DMBP) and 4,4-difluorobenzophenone (4,4-DFBP) are mixed in a molar ratio of 1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S3, and the average potential difference versus lithium between the different aromatic compounds was 0.128 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained 4,4-DMBP and 4,4-DFBP, and the coating amount of the aromatic composition in the negative electrode material was 0.1 wt %.

[0185] Example 4 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP) and 4,4-difluorobenzophenone (4,4-DFBP) are mixed in a molar ratio of 1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S4 and the average potential difference vs. lithium between the different aromatic compounds was 0.152 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained BP and 4,4-DFBP, and the coating amount of the aromatic composition in the negative electrode material was 0.1 wt %.

[0186] Example 5 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP) and 4,4-difluorobenzophenone (4,4-DFBP) are mixed in a molar ratio of 2:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S5, and the average potential difference versus lithium between the different aromatic compounds was 0.133 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained BP and 4,4-DFBP, and the coverage of the layer made of an aromatic composition in the negative electrode material was 0.3 wt %.

[0187] Example 6 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP), anisole, and 3-fluoroanisole are mixed in a molar ratio of 1:1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S6, and the average potential difference versus lithium between the different aromatic compounds was 0.090 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO xand a lithium silicate material, the layer made of an aromatic composition contained BP, anisole, and 3-fluoroanisole, and the coating amount of the aromatic composition in the negative electrode material was 0.2 wt %.

[0188] Example 7 This embodiment provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP), anisole and diphenyl ether are mixed in a molar ratio of 1:1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S7 and the average potential difference vs. lithium between the different aromatic compounds was 0.094 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and lithium silicate material, the layer made of the aromatic composition contained BP, anisole, and diphenyl ether, and the coating amount of the aromatic composition in the negative electrode material was 0.4 wt %.

[0189] Example 8 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP) and anisole are mixed in a molar ratio of 1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S8, and the average potential difference versus lithium between the different aromatic compounds was 0.121 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained an aromatic compound BP and anisole, and the coating amount of the aromatic composition in the negative electrode material was 0.2 wt %.

[0190] Example 9 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP) and 3-fluoroanisole are mixed in a molar ratio of 1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S9 and the average potential difference vs. lithium between the different aromatic compounds was 0.169 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained BP and 3-fluoroanisole, and the coating amount of the aromatic composition in the negative electrode material was 0.2 wt %.

[0191] Example 10 This example provides a method for pre-lithiation of negative electrode materials for lithium-ion batteries, and refers to Example 1, except as follows. 1) Benzophenone (BP), dimethylbiphenyl (4,4-DMBP), and 4,4-difluorobenzophenone (4,4-DFBP) were mixed in a molar ratio of 1:1:1 to obtain an aromatic composition. 0.1 mol of the aromatic composition was dissolved in 200 mL of a mixed solvent of ethyl cellulose (EC) and dimethyl carbonate (DMC), and the molar ratio of EC:DMC was set to 1:1. The mixture was stirred magnetically for 30 min to obtain an organic solution. 2) 0.45 mol of lithium pieces with a lithium content of more than 99.5% was added to the organic solution and left to stand for 10 minutes until the lithium was fully dissolved to form a lithiation solution. The concentration of the lithiation solution was 0.5 mol / L, and the average potential difference with respect to lithium between different aromatic compounds was 0.080 V. 3) 10 g of SiO powder (0.22 mol) was added to 200 mL of the lithium solution and treated with magnetic stirring for 30 min. After suction filtration, the mixture was washed three times with absolute ethanol, and after filtration, it was placed in a glove box and dried by natural evaporation for 30 min to obtain pre-lithiated SiO powder, designated as S10. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained BP, 4,4-DMBP, and 4,4-DFBP, and the coating amount of the aromatic composition in the negative electrode material was 0.5 wt %.

[0192] Example 11 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP), dimethylbiphenyl (4,4-DMBP) and biphenyl are mixed in a molar ratio of 1:1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S11 and the average potential difference vs. lithium between the different aromatic compounds was 0.108 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained BP, 4,4-DMBP, and biphenyl, and the coating amount of the aromatic composition in the negative electrode material was 0.3 wt %.

[0193] Example 12 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that dimethylbiphenyl (4,4-DMBP) and biphenyl are mixed in a molar ratio of 1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S12. The average potential difference versus lithium between the different aromatic compounds was 0.155 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained 4,4-DMBP and biphenyl, and the coating amount of the aromatic composition in the negative electrode material was 0.2 wt %.

[0194] Example 13 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that dimethylbiphenyl (4,4-DMBP) and 2-methylbiphenyl are mixed in a molar ratio of 1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S13, and the average potential difference vs. lithium between the different aromatic compounds was 0.089 V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained 4,4-DMBP and 2-methylbiphenyl, and the coating amount of the aromatic composition in the negative electrode material was 0.3 wt %.

[0195] Example 14 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that benzophenone (BP) and 2,6-dimethylpyridine are mixed in a molar ratio of 1:1 to obtain an aromatic composition. The pre-lithiated SiO powder prepared was designated S14 and the average potential difference vs. lithium between the different aromatic compounds was 0.085V. The negative electrode material produced in this example has a core and a layer of an aromatic composition, the layer of the aromatic composition at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the layer made of an aromatic composition contained BP and 2,6-dimethylpyridine, and the coating amount of the aromatic composition in the negative electrode material was 0.2 wt %.

[0196] Example 15 This example provides a method for pre-lithiation of negative electrode materials for lithium ion batteries, which refers to Example 1, except that the negative electrode raw material is SiO powder containing a carbon coating layer. The pre-lithiated SiO powder produced is designated S15. The negative electrode material produced in this example has a core and an outer coating layer, the outer coating layer at least partially covering the core, and the core is made of Si, SiO x and a lithium silicate material, the outer coating layer included a carbon coating layer and a layer made of an aromatic composition, and the coating amount of the aromatic composition in the negative electrode material was 0.5 wt %.

[0197] Comparative Example 1 1) 10 g of SiO powder (0.22 mol) and 3.15 g of Li (0.45 mol) were mixed to obtain a mixture. 2) The mixture was added to 200 mL of a mixed solvent of ethyl cellulose (EC) and dimethyl carbonate (DMC), and the molar ratio of EC:DMC was 1:1. 3) Treat with magnetic stirring for 30 min (experimental group 1) and 60 min (experimental group 2), respectively, and then suction filter, wash with absolute ethanol three times, filter, and then place in a glove box and dry for 30 min by natural evaporation to obtain pre-lithiated SiO powders, designated as D1 and D101.

[0198] Comparative Example 2 1) 0.1 mol of benzophenone (BP) was dissolved in 200 mL of ethylene glycol dimethyl ether (DME) and stirred for 30 min with a magnetic stirrer to obtain a mixed solution. 2) 0.45 mol of lithium pieces with a lithium content of more than 99.5% was added to the mixed solution, and the solution was left to stand for 10 minutes to fully dissolve the lithium, thereby obtaining a lithiated solution. 3) 10 g of SiO powder (0.22 mol) was added to the lithiation solution, and the mixture was stirred for 30 min by magnetic stirring. After suction filtration, the mixture was washed three times with absolute ethanol, and after filtration, the mixture was placed in a glove box and dried for 30 min by natural evaporation to obtain a pre-lithiated SiO powder, designated as D2.

[0199] Comparative Example 3 1) 0.1 mol of dimethylbiphenyl (4,4-DMBP) was dissolved in 200 mL of ethylene glycol dimethyl ether (DME) and treated with magnetic stirring for 30 minutes to obtain a mixed solution. 2) 0.45 mol of lithium pieces with a lithium content of more than 99.5% was added to the mixed solution, and the solution was left to stand for 10 minutes to fully dissolve the lithium, thereby obtaining a lithiated solution. 3) 10 g of SiO powder (0.22 mol) was added to the lithiation solution and treated with magnetic stirring for 30 min. After suction filtration, the solution was washed three times with absolute ethanol, and after filtration, it was placed in a glove box and dried by natural evaporation for 30 min to obtain pre-lithiated SiO powder, designated as D3.

[0200] Comparative Example 4 1) 0.1 mol of 4,4-difluorobenzophenone (4,4-DFBP) was dissolved in 200 mL of ethylene glycol dimethyl ether (DME) and treated with magnetic stirring for 30 min to obtain a mixed solution. 2) 0.45 mol of lithium pieces with a lithium content of more than 99.5% was added to the mixed solution, and the solution was left to stand for 10 minutes to fully dissolve the lithium, thereby obtaining a lithiated solution. 3) 10 g of SiO powder (0.22 mol) was added to the lithiation solution and treated with magnetic stirring for 30 min. After suction filtration, the solution was washed three times with absolute ethanol, and after filtration, it was placed in a glove box and dried by natural evaporation for 30 min to obtain pre-lithiated SiO powder, designated as D4.

[0201] Comparative Example 5 The SiO powder without any treatment was designated as D5.

[0202] Performance test of experimental group 1: The negative electrode material samples S1, S101, S2 to S15 produced in Examples 1 to 15 and the comparative sample D1, D101, D2, D3, D4, and D5 were each slurried with sodium carboxymethylcellulose, styrene butadiene rubber, conductive graphite (KS-6), and carbon black (SP) in a ratio of 92:2:2:2:2, which was uniformly applied onto copper foil and baked to produce a negative electrode sheet. The negative electrode sheet was assembled in a glove box in an argon gas atmosphere to form a coin-type battery. A polypropylene microporous film was used as the separator, 1 mol / L lithium hexafluorophosphate (solvent: a mixture of ethylene carbonate, methyl ethyl carbonate, and dimethyl carbonate) was used as the electrolyte, and metallic lithium pieces were used as the counter electrode.

[0203] The above 22 sets of batteries were subjected to an initial coulombic efficiency test and a reversible capacity test using a CT2001A battery test system manufactured by Aidensha, and the measured test data are shown in Table 1.

[0204] For the above 22 SiO powder samples, the silicon particle size, specific surface area, and pH value were measured, and data such as the measured silicon particle median size, specific surface area, and pH value are shown in Table 1.

[0205] [Table 1]

[0206] As can be seen from the experimental data in Table 1, in Comparative Example 1, there is no pretreatment for metallic lithium and spare lithium electrode sheet (or powder), so the initial battery effect is not improved. In Comparative Example 2, the lithium source is treated with a non-substituted aromatic compound (biphenyl), and the lithium insertion depth is greatly limited, and the initial battery effect after the pre-lithiation treatment is only 78.1%, which shows that the non-substituted aromatic compound only has a high potential after lithiation and limits the reaction strength with SiO. In Comparative Example 3 and Comparative Example 4, the lithium source is treated with a substituted aromatic compound, and the pre-lithiation effect is achieved to a certain extent, the molar ratio of the substituted aromatic compound to SiO is 0.1:0.22, the initial effect is about 83%, the concentration of the substituted aromatic compound is low, and the lithium insertion efficiency and lithium insertion depth are reduced.

[0207] On the other hand, in Examples 1 to 15, by using a combination of different substituted aromatic compounds, the combination of different substituted aromatic compounds has a certain synergistic effect, and the different potential differences are combined to establish a potential gradient and a lithium insertion path, and the lithium insertion depth and lithium insertion efficiency are obviously improved. As can be seen from the data of the initial effect, each combination shows an extremely high lithium insertion capacity, and in the low-temperature prelithiation treatment, the silicon particles are almost not grown, which avoids the expansion of the electrode sheet due to the increase in crystal grains in the prelithiation treatment, causing the silicon particles on the electrode sheet to fall off, and prevents the lithium particles from growing at all due to the low-temperature prelithiation.

[0208] As can be seen from Examples 1 to 15, the molar ratio of Li-aromatic compound complex to negative electrode powder material is 0.1:0.22=0.46, and at a low concentration ratio, the initial effect of the powder material after pre-lithiation reaches more than 90% within a short time (30 min), and the pre-lithiation efficiency of the powder material is obviously improved. It has been shown that the composition of substituted aromatic compounds has obvious advantages in terms of lithium insertion, and many combinations thereof can be selected. In the organic solution with different combinations, the selectivity is optimized, and therefore, in Examples 1 and 15, there is a certain difference in the initial effect.

[0209] When the lithiation time of SiO was increased from 30 min to 60 min, the lithiation treatment was performed with the lithiation solution prepared from the substituted aromatic compound alone or in the composition, and the initial battery performance was all improved. As can be seen from the initial performance data, the material has a very high lithium insertion capacity, and it is clear that the composition of the substituted aromatic compound with a low concentration has a high advantage in terms of lithium insertion.

[0210] As can be seen from all the above test data, the aromatic composition made of substituted aromatic compounds has a high advantage in terms of solvation and prelithiation, the material has a very high lithium insertion capacity, the initial efficiency and capacity of the battery are greatly improved, and the low concentration of substituted aromatic compounds can reduce the loss of metallic lithium.

[0211] Although the present application has disclosed preferred embodiments above, the claims are not intended to limit the scope of the present application. Those skilled in the art may make some changes or modifications without departing from the concept of the present application. Therefore, the patent scope of the present application shall be within the scope defined by the claims of the present application. [Industrial Applicability]

[0212] As mentioned above, the present disclosure provides anode materials, their preparation methods and uses. The combination of different aromatic compounds corresponding to the combination of different potential differences establishes a lithium-insertion potential difference gradient path, and the lithium source and the anode materials spontaneously and quickly carry out chemical lithium insertion in organic solvent, thereby effectively improving the lithium insertion depth and lithium insertion efficiency, reducing irreversible capacity loss, and improving battery capacity.

Claims

1. The method includes a step of lithiating a negative electrode raw material with a lithiating solution containing a Li-aromatic composition, The aromatic composition comprises an unsubstituted aromatic compound and a substituted aromatic compound, or comprises at least two substituted aromatic compounds; A method for producing a negative electrode material, which satisfies at least one of the following characteristics (1) to (8): (1) The substituent of the substituted aromatic compound includes at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen, an ester group, an amino group, a substituted carbonyl group, and an amide group; (2) The substituent of the substituted aromatic compound includes an alkyl group, and the alkyl group includes at least one of linear or branched alkyl groups having 1 to 6 carbon atoms; (3) The substituent of the substituted aromatic compound contains an alkoxy group, and the alkoxy group contains at least one of linear or branched alkoxy groups having 1 to 4 carbon atoms; (4) The substituent of the substituted aromatic compound includes an aryloxy group, and the aryloxy group includes a phenoxy group; (5) The substituent of the substituted aromatic compound includes a halogen, and the halogen includes at least one of -F, -Cl, -Br, and -I; (6) The substituent of the substituted aromatic compound includes an ester group, and the ester group includes at least one of an alkyl ester group and an aryl ester group; (7) The substituent of the substituted aromatic compound includes an amino group, and the amino group is -NH 2 , -R 2 N.H. 2 , -NHR 3 and -NR 4 R 5 wherein R 2 is at least one selected from an alkylene group or a substituted alkylene group having 1 to 3 carbon atoms; R 3 , R 4 and R 5 are each independently at least one selected from linear or branched alkyl groups having 1 to 3 carbon atoms; (8) The substituent of the substituted aromatic compound includes a substituted carbonyl group, and the substituted carbonyl group is -COR 6 Wherein R 6 contains at least one of a linear or branched alkyl group having 1 to 6 carbon atoms, a phenyl group, or a substituted phenyl group.

2. The method according to claim 1, which satisfies at least one of the following characteristics (1) to (2): (1) the aromatic compound includes at least one of benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, pyrene, tetracene, and pyridine; (2) The number of substituents in the substituted aromatic compound is 1 or more.

3. the aromatic composition comprises an unsubstituted aromatic compound and a substituted aromatic compound; The method according to claim 2, which satisfies at least one of the following characteristics (1) to (5): (1) In the aromatic composition, the content of the substituted aromatic compound is 3 mol% to 97 mol%; (2) In the aromatic composition, the content of the alkyl-substituted aromatic compound is 10 mol% to 90 mol%; (3) In the aromatic composition, the content of the alkoxy-substituted aromatic compound is 20 mol% to 80 mol%; (4) In the aromatic composition, the content of the halogen-substituted aromatic compound is 5 mol% to 40 mol%; (5) In the aromatic composition, the content of the substituted carbonyl-substituted aromatic compound is 10 mol % to 60 mol %.

4. The aromatic composition comprises at least two substituted aromatic compounds; The method according to any one of claims 1 to 3, which satisfies at least one of the following characteristics (1) to (8): (1) In the aromatic composition, the content of the alkyl-substituted aromatic compound is 10 mol% to 80 mol% and the content of the alkoxy-substituted aromatic compound is 20 mol% to 90 mol%; (2) In the aromatic composition, the content of the alkyl-substituted aromatic compound is 60 mol% to 95 mol% and the content of the halogen-substituted aromatic compound is 5 mol% to 40 mol%; (3) In the aromatic composition, the content of the alkoxy-substituted aromatic compound is 60 mol% to 95 mol% and the content of the halogen-substituted aromatic compound is 5 mol% to 40 mol%; (4) In the aromatic composition, the content of one kind of alkyl-substituted aromatic compound is 10 mol% to 90 mol%, and the content of another kind of alkyl-substituted aromatic compound is 10 mol% to 90 mol%; (5) In the aromatic composition, the content of the alkyl-substituted aromatic compound is 20 mol% to 50 mol%, the content of the halogen-substituted aromatic compound is 20 mol% to 50 mol%, and the content of the substituted carbonyl-substituted aromatic compound is 20 mol% to 50 mol%; (6) In the aromatic composition, the content of the halogen-substituted aromatic compound is 10 mol% to 50 mol% and the content of the substituted carbonyl-substituted aromatic compound is 50 mol% to 90 mol%; (7) In the aromatic composition, the content of the substituted carbonyl-substituted aromatic compound is 20 mol% to 50 mol%, the content of the alkoxy-substituted aromatic compound is 20 mol% to 50 mol%, and the content of the halogen-substituted aromatic compound is 20 mol% to 50 mol%; (8) In the aromatic composition, the content of the alkoxy-substituted aromatic compound is 50 mol % to 95 mol % and the content of the substituted carbonyl-substituted aromatic compound is 5 mol % to 50 mol %.

5. The method according to any one of claims 1 to 4, which satisfies at least one of the following characteristics (1) to (4): (1) the aromatic composition comprises an unsubstituted aromatic compound and at least two substituted aromatic compounds; (2) the aromatic composition comprises an unsubstituted aromatic compound and at least two substituted aromatic compounds, the substituted aromatic compounds including an alkyl-substituted aromatic compound and an amino-substituted aromatic compound; (3) The lithiation solution is mainly composed of an organic solution of an aromatic composition and a lithium source, and the organic solvent of the organic solution includes at least one of an ether-based, a carbonate-based, a benzene-based, and a ketone-based solvent; (4) The lithium-ion solution is mainly composed of a mixture of an organic solution of an aromatic composition and a lithium source, and the concentration of the aromatic composition contained in the organic solution of the aromatic composition is 0.2 mol / L to 2 mol / L.

6. the lithiation solution is composed primarily of an organic solution of an aromatic composition and a lithium source; The method according to any one of claims 1 to 4, which satisfies at least one of the following characteristics (1) to (10): (1) the lithium source comprises at least one of lithium metal and a lithium alloy having a lithium content of greater than 40%; (2) the lithium source is at least one of a powder, a sheet material, and a block material; (3) the molar ratio of the lithium source (in terms of Li) to the aromatic composition is greater than 2; (4) During the preparation of the lithium doped solution, the temperature of the mixing is 10°C to 30°C, and the time of the mixing is 5 min to 10 min; (5) In the lithiation solution, the molar ratio of the Li-aromatic composition to the negative electrode raw material is (0.2-2):1; (6) The negative electrode raw material includes at least one of a silicon-based material, a carbon-based material, and a silicon carbon composite; (7) The negative electrode raw material is in the form of a powder or an electrode sheet, and the particle size of the powder is smaller than 50 μm; (8) The negative electrode raw material contains silicon monoxide; (9) After the lithiation, perform solid-liquid separation to collect and wash the solid to obtain a lithiation-treated negative electrode material; (10) The method further includes a step of drying the negative electrode material after the lithiation treatment to obtain a pre-lithiated negative electrode material.

7. The method includes a step of lithiating a negative electrode raw material with a lithiating solution containing a Li-aromatic composition, The aromatic composition comprises at least two aromatic compounds each having a different electrical potential; the at least two aromatic compounds each having a different potential include an unsubstituted aromatic compound and a substituted aromatic compound, or at least two substituted aromatic compounds; A method for producing a negative electrode material, which satisfies at least one of the following characteristics (1) to (8): (1) The substituent of the substituted aromatic compound includes at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen, an ester group, an amino group, a substituted carbonyl group, and an amide group; (2) The substituent of the substituted aromatic compound includes an alkyl group, and the alkyl group includes at least one of linear or branched alkyl groups having 1 to 6 carbon atoms; (3) The substituent of the substituted aromatic compound contains an alkoxy group, and the alkoxy group contains at least one of linear or branched alkoxy groups having 1 to 4 carbon atoms; (4) The substituent of the substituted aromatic compound includes an aryloxy group, and the aryloxy group includes a phenoxy group; (5) The substituent of the substituted aromatic compound includes a halogen, and the halogen includes at least one of -F, -Cl, -Br, and -I; (6) The substituent of the substituted aromatic compound includes an ester group, and the ester group includes at least one of an alkyl ester group and an aryl ester group; (7) The substituent of the substituted aromatic compound includes an amino group, and the amino group is -NH 2 , -R 2 N.H. 2 , -NHR 3 and -NR 4 R 5 wherein R 2 is at least one selected from an alkylene group or a substituted alkylene group having 1 to 3 carbon atoms; R 3 , R 4 and R 5 are each independently at least one selected from linear or branched alkyl groups having 1 to 3 carbon atoms; (8) The substituent of the substituted aromatic compound includes a substituted carbonyl group, and the substituted carbonyl group is -COR 6 Wherein R 6 contains at least one of a linear or branched alkyl group having 1 to 6 carbon atoms, a phenyl group, or a substituted phenyl group.

8. The method according to claim 7, wherein the aromatic composition satisfies at least one of the following characteristics (1) to (3): (1) The range of potential of the aromatic compound with respect to lithium is 0 to 0.5 V vs. Li / Li + is; (2) There is a potential gradient with respect to lithium between the different aromatic compounds; (3) Difference in average potential with respect to lithium between different aromatic compounds ΔV vs Li / Li + satisfies 0<ΔV≦0.3V.

9. Difference in the average potential of different aromatic compounds with respect to lithium ΔV vs Li / Li + The method according to claim 8 , wherein ΔV satisfies 0<ΔV≦0.1V.

10. adding a lithium source to a mixed solution containing an aromatic composition and an organic solvent to obtain a lithiated solution containing a Li-aromatic compound, the aromatic composition comprising at least two aromatic compounds each having a different branched chain, or one aromatic compound having a branched chain and an unmodified aromatic compound; adding a powdered negative electrode material to the lithiated solution and drying to obtain a pre-lithiated negative electrode material; A method for producing a negative electrode material, which satisfies at least one of the following characteristics (1) to (6): (1) The branched chain includes at least one of an alkane-based branched chain, an ether-based branched chain, a halogen-based branched chain, an ester-based branched chain, an amine-based branched chain, and a benzene ring-containing branched chain; (2) The branched chain includes an alkane-based branched chain, and the alkane-based branched chain is —CH 3 , -C 2 H 5 and -C 3 H 7 Contains at least one of the following: (3) The branched chain includes an ether-based branched chain, and the ether-based branched chain is —OCH 3 , -OCH 2 CH 3 and -OC 6 H 5 Contains at least one of the following: (4) The branched chain includes a halogen-based branched chain, and the halogen-based branched chain includes at least one of -Cl, -F, -Br, and -I; (5) The branched chain includes an ester-based branched chain, and the ester-based branched chain includes at least one of a benzyl ester-based branched chain and a benzoate ester-based branched chain; (6) The branched chain includes an amine-based branched chain, and the amine-based branched chain is -NH 2 , -CH 2 N.H. 2 , -CH 2 CH 2 N.H. 2 , -CH(CH 3 ) N.H. 2 , -N(CH 3 ) 2 , -NHCH 2 CH 3 , -NHCH 2 CH 2 CH 3 and -NHCOCH 3 The composition includes at least one of the following:

11. The method according to claim 10, wherein the following characteristic (1) is satisfied: (1) The unmodified aromatic compound includes at least one of benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, pyrene, and tetracene.

12. The aromatic composition comprises one aromatic compound having a branched chain and an unmodified aromatic compound; The method according to claim 11, which satisfies at least one of the following characteristics (1) to (4): (1) In the aromatic composition, the content of the branched aromatic compound is 3 mol % to 97 mol %; (2) In the aromatic composition, the content of the aromatic compound having an alkane branched chain is 10 mol% to 90 mol%; (3) In the aromatic composition, the content of the aromatic compound having an ether-based branched chain is 20 mol% to 80 mol%; (4) In the aromatic composition, the content of the aromatic compound having a halogen-containing branched chain is 5 mol % to 40 mol %.

13. The aromatic composition includes at least two aromatic compounds each having a different branched chain, and the combination of the at least two aromatic compounds each having a different branched chain is It contains 10 mol % to 80 mol % of an aromatic compound having an alkane branched chain and 20 mol % to 90 mol % of an aromatic compound having an ether branched chain, or comprising 60 mol % to 95 mol % of an aromatic compound having an alkane branched chain and 5 mol % to 40 mol % of an aromatic compound having a halogen branched chain; 13. The method according to claim 10, 11 or 12, comprising 60 mol % to 95 mol % of an aromatic compound having an ether-based branched chain and 5 mol % to 40 mol % of an aromatic compound having a halogen-based branched chain.

14. The method according to any one of claims 10 to 13, which satisfies at least one of the following characteristics (1) to (4): (1) The aromatic composition comprises at least two aromatic compounds each having a different branched chain, and an unmodified aromatic compound; (2) the aromatic composition comprises at least two aromatic compounds each having a different branched chain, and an unmodified aromatic compound, and at least one aromatic compound has an alkane-based or amine-based branched chain; (3) The organic solvent includes at least one of dimethyl ether, dimethyl carbonate, tetrahydrofuran, carbonate esters, toluene, benzene, diethyl ether, propylene oxide, and ketone solvents; (4) The concentration of the aromatic compound contained in the mixed solution is 0.2 mol / L to 2.0 mol / L.

15. The method according to any one of claims 10 to 13, which satisfies at least one of the following characteristics (1) to (10): (1) the lithium source comprises at least one of lithium metal and a lithium alloy having a lithium content greater than 40%; (2) a molar ratio of elemental lithium to the aromatic composition in the lithium source is greater than 2; (3) The dissolution time of the lithium source is 5 min to 10 min, and the dissolution temperature of the lithium source is 10 ° C to 30 ° C; (4) the molar ratio of the Li-aromatic compound to the negative electrode powder material is (0.2-2):1; (5) The negative electrode powder material includes at least one of a silicon-based material, a carbon-based material, and a silicon carbon composite; (6) the particle size of the negative electrode powder material is smaller than 50 μm; (7) adding the negative electrode powder material to the lithiation solution and then stirring, the stirring manner including at least one of magnetic stirring, ultrasonic stirring and mechanical stirring; (8) adding the negative electrode powder material to the lithiation solution and then stirring, the stirring time being 15 min to 60 min; (9) The drying is performed under a protective gas, and the protective gas includes at least one of helium gas, neon gas, argon gas, krypton gas, and xenon gas; (10) The drying time is 15 minutes to 60 minutes.

16. adding a lithium source to a mixed solution containing an aromatic composition and an organic solvent to obtain a lithiated solution containing a Li-aromatic compound, the aromatic composition including an aromatic compound having an alkane-based branched chain and an aromatic compound having a halogen-based branched chain; 11. The method of claim 10, comprising the steps of adding silicon monoxide to the lithiated solution, stirring, filtering, washing with an organic solvent, filtering, and drying to obtain a prelithiated silicon monoxide material.

17. nanosilicon, silicon-oxygen-lithium-containing compounds and aromatic compositions, The silicon-oxygen-lithium-containing compound is Li 2 S 2 O 5 , Li 2 SiO 3 and Li 4 SiO 4 At least one of the following is included: the aromatic composition at least partially coats the nanosilicon and the silicon-oxygen-lithium-containing compound; The aromatic composition comprises at least two substituted aromatic compounds each having a different potential, and a difference in average potential with respect to lithium between the at least two substituted aromatic compounds, ΔV vs Li / Li + , satisfies 0<ΔV≦0.3 V; A negative electrode material that satisfies at least one of the following characteristics (1) to (8): (1) The substituent of the substituted aromatic compound includes at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen, an ester group, an amino group, a substituted carbonyl group, and an amide group; (2) The substituent of the substituted aromatic compound includes an alkyl group, and the alkyl group includes at least one of linear or branched alkyl groups having 1 to 6 carbon atoms; (3) The substituent of the substituted aromatic compound contains an alkoxy group, and the alkoxy group contains at least one of linear or branched alkoxy groups having 1 to 4 carbon atoms; (4) The substituent of the substituted aromatic compound includes an aryloxy group, and the aryloxy group includes a phenoxy group; (5) The substituent of the substituted aromatic compound includes a halogen, and the halogen includes at least one of -F, -Cl, -Br, and -I; (6) The substituent of the substituted aromatic compound includes an ester group, and the ester group includes at least one of an alkyl ester group and an aryl ester group; (7) The substituent of the substituted aromatic compound includes an amino group, and the amino group is -NH 2 , -R 2 N.H. 2 , -NHR 3 and -NR 4 R 5 wherein R 2 is at least one selected from an alkylene group or a substituted alkylene group having 1 to 3 carbon atoms; R 3 , R 4 and R 5 are each independently at least one selected from linear or branched alkyl groups having 1 to 3 carbon atoms; (8) The substituent of the substituted aromatic compound includes a substituted carbonyl group, and the substituted carbonyl group is -COR 6 Wherein R 6 contains at least one of a linear or branched alkyl group having 1 to 6 carbon atoms, a phenyl group, or a substituted phenyl group.

18. the negative electrode material includes a core and a layer comprising an aromatic composition; The negative electrode material according to claim 17, wherein the negative electrode material satisfies at least one of the following characteristics (1) to (10): (1) the core comprises nanosilicon and a silicon-oxy-lithium-containing compound; (2) the nanosilicon is dispersed in the silicon-oxygen-lithium-containing compound; (3) The core is SiO x (wherein x satisfies 0.4≦x≦1.6); (4) The median diameter of the negative electrode material is 4 μm to 8 μm; (5) The specific surface area of ​​the negative electrode material is 1.5 m 2 / g to 4.2 m 2 / g; (6) The pH value of the negative electrode material is 10 to 11.5; (7) The negative electrode material further comprises a carbon coating layer; (8) The negative electrode material further comprises a carbon coating layer, the carbon coating layer coating the core; (9) The negative electrode material further comprises a carbon coating layer, and the aromatic composition is distributed within channels in the carbon coating layer and on an outer surface of the carbon coating layer; (10) In the negative electrode material, the coating amount of the aromatic composition is 0 wt % to 2 wt %.

19. A current collector and a negative electrode layer provided on a surface of the current collector, The negative electrode layer includes a negative electrode material, The negative electrode material comprises nanosilicon, a silicon-oxygen-lithium-containing compound, and an aromatic composition; The silicon-oxygen-lithium-containing compound is Li 2 S 2 O 5 , Li 2 SiO 3 and Li 4 SiO 4 At least one of the following is included: the aromatic composition at least partially coats the nanosilicon and the silicon-oxygen-lithium-containing compound; The aromatic composition comprises at least two substituted aromatic compounds each having a different potential, and a difference in average potential with respect to lithium between the at least two substituted aromatic compounds, ΔV vs Li / Li + , satisfies 0<ΔV≦0.3 V; A negative electrode sheet that satisfies at least one of the following characteristics (1) to (8): (1) The substituent of the substituted aromatic compound includes at least one of an alkyl group, an alkoxy group, an aryloxy group, a halogen, an ester group, an amino group, a substituted carbonyl group, and an amide group; (2) The substituent of the substituted aromatic compound includes an alkyl group, and the alkyl group includes at least one of linear or branched alkyl groups having 1 to 6 carbon atoms; (3) The substituent of the substituted aromatic compound contains an alkoxy group, and the alkoxy group contains at least one of linear or branched alkoxy groups having 1 to 4 carbon atoms; (4) The substituent of the substituted aromatic compound includes an aryloxy group, and the aryloxy group includes a phenoxy group; (5) The substituent of the substituted aromatic compound includes a halogen, and the halogen includes at least one of -F, -Cl, -Br, and -I; (6) The substituent of the substituted aromatic compound includes an ester group, and the ester group includes at least one of an alkyl ester group and an aryl ester group; (7) The substituent of the substituted aromatic compound includes an amino group, and the amino group is -NH 2 , -R 2 N.H. 2 , -NHR 3 and -NR 4 R 5 wherein R 2 is at least one selected from an alkylene group or a substituted alkylene group having 1 to 3 carbon atoms; R 3 , R 4 and R 5 are each independently at least one selected from linear or branched alkyl groups having 1 to 3 carbon atoms; (8) The substituent of the substituted aromatic compound includes a substituted carbonyl group, and the substituted carbonyl group is -COR 6 Wherein R 6 contains at least one of a linear or branched alkyl group having 1 to 6 carbon atoms, a phenyl group, or a substituted phenyl group.

20. A lithium ion battery comprising the negative electrode sheet of claim 19.

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