WO2021128091A1 - 负极及其制备方法 - Google Patents

负极及其制备方法 Download PDF

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Publication number
WO2021128091A1
WO2021128091A1 PCT/CN2019/128441 CN2019128441W WO2021128091A1 WO 2021128091 A1 WO2021128091 A1 WO 2021128091A1 CN 2019128441 W CN2019128441 W CN 2019128441W WO 2021128091 A1 WO2021128091 A1 WO 2021128091A1
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negative electrode
bonds
preparing
auxiliary agent
vibration
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PCT/CN2019/128441
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English (en)
French (fr)
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王可飞
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宁德新能源科技有限公司
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Priority to JP2022519826A priority Critical patent/JP2022550179A/ja
Priority to US17/055,335 priority patent/US11978902B2/en
Priority to PCT/CN2019/128441 priority patent/WO2021128091A1/zh
Publication of WO2021128091A1 publication Critical patent/WO2021128091A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/387—Tin or alloys based on tin
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the application relates to the field of energy storage, in particular to a negative electrode and a preparation method thereof.
  • the negative electrode active material, dispersant, binder, and conductive agent are dissolved in a solvent to form a negative electrode slurry.
  • the negative electrode active material, dispersant, binder, and conductive agent are usually difficult to be uniformly dispersed, resulting in uneven surface tension of the negative electrode slurry.
  • the difference in surface tension will cause shrinkage, pits or edge shrinkage, which has an adverse effect on the apparent performance of the negative electrode and the performance of the electrochemical device, affects the safety and qualification rate of the product, and further increases the production cost.
  • the embodiments of the present application provide a negative electrode and a preparation method thereof to at least to some extent solve at least one problem existing in the related field.
  • the present application provides a method for preparing a negative electrode, which includes the step of adding an auxiliary agent having Si-C and Si-O bonds.
  • the auxiliary agent having Si-C and Si-O bonds is mixed with the solvent.
  • the auxiliary agent with Si-C and Si-O bonds is added after adding the binder.
  • the method includes the following steps:
  • S1 a mixing step, wherein the negative electrode active material, dispersant, binder, solvent, and the auxiliary agent with Si-C and Si-O bonds are uniformly mixed to obtain a negative electrode slurry;
  • S2 coating step, coating the negative electrode slurry prepared in S1 on the negative electrode current collector at a coating speed of 10 m/min to 100 m/min to obtain an initial pole piece;
  • S3 a drying step, placing the initial pole piece obtained in S2 in a vacuum drying device for drying, at a drying temperature of 80° C. to 150° C., to obtain the negative electrode.
  • the auxiliary agent having Si-C and Si-O bonds has at least one of the following characteristics:
  • the oxidation potential is not less than 4.5V, and the reduction potential is not more than 0.5V;
  • the auxiliary agent having Si-C and Si-O bonds includes polyether siloxane.
  • the auxiliary agent having Si-C and Si-O bonds includes a composite silicone polyether compound, a polyether modified trisiloxane, or a polyether modified silicone polyether silicone At least one of alkanes.
  • the negative active material includes at least one of natural graphite, artificial graphite, soft carbon, hard carbon, silicon oxygen, silicon carbon, silicon alloy, or tin alloy.
  • the solvent is deionized water or N-methylpyrrolidone.
  • the vibration processing is performed simultaneously in any step of S1, S2, or S3, and the vibration processing is at least one of mechanical vibration or ultrasonic vibration.
  • vibration processing is performed after any step of S1, S2, or S3, and the vibration is at least one of mechanical vibration or ultrasonic vibration.
  • the vibration frequency of the vibration treatment is 100 Hz to 800 Hz
  • the amplitude is 0.01 mm to 0.5 mm
  • the vibration time is 1 minute to 5 minutes.
  • the vibration treatment is performed multiple times, and the vibration frequency of the vibration treatment at least once is lower than the vibration frequency of the previous vibration treatment.
  • the present application provides a negative electrode, which is obtained by the method for preparing the negative electrode according to the present application.
  • the content of the auxiliary agent having Si-C and Si-O bonds in the negative electrode is 500 ppm or less, preferably 300 ppm or less.
  • the contact angle of the surface of the negative electrode relative to diethyl carbonate is reduced by more than 10%.
  • the present application provides an electrochemical device, including a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the negative electrode is obtained according to the method for preparing a negative electrode of the present application or the negative electrode is the negative electrode of the present application. .
  • the present application provides an electronic device including the electrochemical device according to the present application.
  • Figure 1 shows the surface appearance of the negative electrode of Comparative Example 1.
  • FIG. 2 shows the external appearance view of the negative electrode of Example 2.
  • a list of items connected by the term "at least one of” or other similar terms can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (exclude B); B and C (exclude A); or all of A, B, and C.
  • Project A can contain a single element or multiple elements. Project B can contain a single element or multiple elements. Project C can contain a single element or multiple elements.
  • the term "at least one of" has the same meaning as the term "at least one of”.
  • the negative electrode active material, dispersant, binder and conductive agent are usually dissolved in a solvent to form the negative electrode slurry, and then the negative electrode slurry is coated on the negative electrode current collector, and the steps are followed by drying. Then the negative electrode is formed. Due to the poor compatibility of the negative electrode active material with the solvent, the dispersant is usually difficult to fully function, resulting in the negative electrode active material, dispersant, binder and conductive agent, etc. usually difficult to uniformly disperse in the solvent, so that the negative electrode slurry is not uniform enough . Inhomogeneous negative electrode slurry will cause uneven surface tension. The difference in surface tension can cause shrinkage, pits or edge shrinkage (as shown in Figure 1), which has an adverse effect on the apparent performance of the negative electrode and the performance of the electrochemical device, affecting the safety and pass rate of the product, and then Increase production costs.
  • This application improves the compatibility between the negative electrode active material and the solvent through a specific preparation method, thereby improving the surface tension of the negative electrode slurry, and reducing the shrinkage, pits or edge shrinkage on the negative electrode surface (as shown in Figure 2) , Thereby improving the quality of the negative electrode and improving the performance of the electrochemical device.
  • the present application provides a method for preparing a negative electrode, which includes the step of adding an auxiliary agent having Si-C and Si-O bonds.
  • the method includes the following steps:
  • the negative electrode active material, the dispersant, the binder, the solvent, and the auxiliary agent having Si-C and Si-O bonds are uniformly mixed to obtain the negative electrode slurry.
  • the auxiliary agent having Si-C and Si-O bonds is mixed with the solvent.
  • the auxiliary agent with Si-C and Si-O bonds is added after adding the binder.
  • the negative active material includes at least one of natural graphite, artificial graphite, soft carbon, hard carbon, silicon oxygen, silicon carbon, silicon alloy, or tin alloy.
  • the solvent is deionized water or N-methylpyrrolidone.
  • the dispersant includes carboxymethyl cellulose, carboxymethyl cellulose derivatives, alginic acid, alginic acid derivatives, polyacrylic acid, polyacrylic acid derivatives, polyamic acid, polyamic acid At least one of derivatives, polyvinyl alcohol, polyvinyl alcohol derivatives, starch, starch derivatives, hydroxypropyl cellulose, or hydroxypropyl cellulose derivatives.
  • the binder includes styrene butadiene rubber, polyacrylate, polytetrafluoroethylene, polyvinyl alcohol, polyurethane, polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, At least one of a vinylidene fluoride-hexafluoropropylene copolymer, a hexafluoropropylene-tetrafluoroethylene copolymer, or a vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer.
  • the auxiliary agent having Si-C and Si-O bonds has at least one of the following characteristics:
  • the oxidation potential is not less than 4.5V, and the reduction potential is not more than 0.5V;
  • the oxidation potential of the auxiliary agent having Si-C and Si-O bonds is not less than 4.5V, and the reduction potential is not more than 0.5V. In some embodiments, the oxidation potential of the auxiliary agent having Si-C and Si-O bonds is not less than 5V, and the reduction potential is not greater than 0.3V.
  • the electrochemical performance of the auxiliary agent with the above oxidation/reduction potential is stable, which helps to improve the cycle and high-temperature storage performance of the electrochemical device.
  • the surface tension of an aqueous solution containing 0.1 wt% of the auxiliary agent having Si-C and Si-O bonds is not greater than 30 mN/m. In some embodiments, the surface tension of an aqueous solution containing 0.1 wt% of the auxiliary agent having Si-C and Si-O bonds is not greater than 25 mN/m. In some embodiments, the surface tension of an aqueous solution containing 0.1 wt% of the auxiliary agent having Si-C and Si-O bonds is not more than 20 mN/m. In some embodiments, the surface tension of an aqueous solution containing 0.1 wt% of the auxiliary agent having Si-C and Si-O bonds is not more than 15 mN/m.
  • the surface tension of an aqueous solution containing 0.1 wt% of the auxiliary agent having Si-C and Si-O bonds is not greater than 10 mN/m.
  • the interface of the negative electrode mixture layer is good.
  • the surface tension of the auxiliary agent with Si-C and Si-O bonds can be measured by the following method: use JC2000D3E contact angle measuring instrument to test the auxiliary agent aqueous solution with a solid content of 1%, and each sample shall be tested at least 3 times , Select at least 3 data and take the average value to get the surface tension of the additive.
  • the auxiliary agent having Si-C and Si-O bonds includes polyether siloxane.
  • the auxiliary agent having Si-C and Si-O bonds includes a composite silicone polyether compound, a polyether modified trisiloxane, or a polyether modified silicone polyether silicone At least one of alkanes.
  • the added amount of the auxiliary agent having Si-C and Si-O bonds is 3000 ppm or less. In some embodiments, the added amount of the auxiliary agent having Si-C and Si-O bonds is 2500 ppm or less. In some embodiments, the added amount of the auxiliary agent having Si-C and Si-O bonds is less than 2000 ppm. In some embodiments, the added amount of the auxiliary agent having Si-C and Si-O bonds is 1500 ppm or less. In some embodiments, the added amount of the auxiliary agent having Si-C and Si-O bonds is less than 1000 ppm. In some embodiments, the added amount of the auxiliary agent having Si-C and Si-O bonds is 500 ppm or less. When the addition amount of the auxiliary agent having Si-C and Si-O bonds is within the above range, the surface tension of the negative electrode slurry can be effectively reduced.
  • the ratio of the negative electrode active material, dispersant, binder, solvent, and the auxiliary agent with Si-C and Si-O bonds added in this step is not particularly limited, as long as it is known to be used in the preparation process of the negative electrode slurry.
  • the ratio can be used.
  • the negative electrode slurry prepared in S1 is coated on the negative electrode current collector at a coating speed of 10 m/min to 100 m/min to obtain an initial pole piece.
  • the initial pole piece obtained in S2 is placed in a vacuum drying device for drying, and the drying temperature is 80° C. to 150° C. to obtain the negative electrode.
  • the vibration processing is performed simultaneously in any step of S1, S2, or S3, and the vibration processing is at least one of mechanical vibration or ultrasonic vibration.
  • vibration processing is performed after any step of S1, S2, or S3, and the vibration is at least one of mechanical vibration or ultrasonic vibration.
  • the vibration treatment can effectively prevent the unevenness of the negative electrode slurry due to the density difference.
  • the vibration frequency of the vibration treatment is 100 Hz to 800 Hz
  • the amplitude is 0.01 mm to 0.5 mm
  • the vibration time is 1 minute to 5 minutes.
  • the vibration treatment is performed multiple times, and the vibration frequency of the vibration treatment at least once is lower than the vibration frequency of the previous vibration treatment.
  • the present application provides a negative electrode, which is obtained by the method for preparing a negative electrode according to the present application.
  • the content of the auxiliary agent having Si-C and Si-O bonds in the negative electrode is 500 ppm or less. In some embodiments, the content of the auxiliary agent having Si-C and Si-O bonds in the negative electrode is 400 ppm or less. In some embodiments, the content of the auxiliary agent having Si-C and Si-O bonds in the negative electrode is 300 ppm or less. In some embodiments, the content of the auxiliary agent having Si-C and Si-O bonds in the negative electrode is less than 200 ppm.
  • the contact angle of the surface of the negative electrode with respect to diethyl carbonate is reduced. Less than 10%.
  • the contact angle refers to the contact angle measured within 10 seconds after dropping a drop of diethyl carbonate on the negative electrode mixture layer.
  • Diethyl carbonate is a commonly used electrolyte solvent.
  • diethyl carbonate as a test indicator of the contact angle can test the wettability of the electrolyte into the negative electrode mixture layer.
  • the decrease in the contact angle of the surface of the negative electrode with respect to diethyl carbonate indicates that the impregnation of the electrolyte into the negative electrode mixture layer is improved, and the liquid retention characteristics of the negative electrode mixture layer are enhanced.
  • the contact angle can be measured by an automatic contact angle measuring meter prepared by Kyowa Interface Science Co., Ltd. or the like.
  • the contact angle ⁇ can be calculated by measuring ⁇ ′ using the distance 2r of the droplet baseline and the height h of the droplet. At this time, it is necessary to drop the liquid droplets in an amount that is not affected by gravity.
  • the non-aqueous solvent used in the contact angle test can be commonly used electrolyte solvents such as diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, methyl propyl carbonate, or methyl isopropyl carbonate.
  • the contact angle of the negative active material layer with respect to the non-aqueous solvent is not greater than 60°. In some embodiments, the contact angle of the negative active material layer with respect to the non-aqueous solvent is not greater than 50° as determined by the contact angle measurement method. In some embodiments, the contact angle of the negative active material layer with respect to the non-aqueous solvent is not greater than 30° as determined by the contact angle measurement method.
  • the positive electrode, the separator, and the electrolyte are not particularly limited, as long as they are known to be useful for electrochemical devices (for example, lithium ion batteries), and the separator and electrolyte.
  • the positive electrode applicable to the embodiments of the present application includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector.
  • the type of positive electrode active material is not particularly limited, as long as it is a positive electrode active material known to be used in electrochemical devices (for example, lithium ion batteries), such as lithium-containing compounds, which can provide high energy density for electrochemical devices.
  • the lithium-containing compound includes one or more of a lithium transition metal composite oxide and a lithium transition metal phosphate compound.
  • the lithium transition metal composite oxide includes lithium and an oxide having one or more transition metal elements.
  • the lithium transition metal phosphate compound is a phosphate compound containing lithium and having one or more transition metal elements.
  • the transition metal element includes one or more of Co, Ni, Mn, and Fe, and these elements can enable the electrochemical device to obtain a higher voltage.
  • the lithium-containing compound has the chemical formula LixM1O 2 or LiyM2PO 4 , where M1 and M2 represent one or more transition metal elements, and the values of x and y vary with the charge/discharge state, and are usually within the following range: 0.05 ⁇ x ⁇ 1.10 and 0.05 ⁇ y ⁇ 1.10.
  • the lithium transition metal composite oxide includes, but is not limited to, LiCoO 2 , LiNiO 2 and a lithium nickel-based transition metal composite oxide represented by the formula LiNi 1-z MzO 2, where M is selected from Co , Mn, Fe, Al, V, Sn, Mg, Ti, Sr, Ca, Zr, Mo, Tc, Ru, Ta, W, Re, Yb, Cu, Zn, Ba, B, Cr, Si, Ga, P One or more of, Sb and Nb, and z satisfies 0.005 ⁇ z ⁇ 0.5.
  • the lithium transition metal phosphate compound includes, but is not limited to, LiFePO 4 and a compound represented by the formula LiFe 1-u Mn u PO 4 , where u ⁇ 1. Using these compounds as the active material of the positive electrode, the resulting electrochemical device has high battery capacity and excellent cycle characteristics.
  • the type of electrolyte is not particularly limited, as long as it is an electrolyte known to be usable in electrochemical devices (for example, lithium ion batteries).
  • the electrolyte includes any non-aqueous solvent known in the prior art that can be used as a solvent for the electrolyte.
  • the non-aqueous solvent includes, but is not limited to, one or more of the following: cyclic carbonate, chain carbonate, cyclic carboxylic acid ester, chain carboxylic acid ester, cyclic ether, chain ether, Phosphorus-containing organic solvents, sulfur-containing organic solvents and aromatic fluorine-containing solvents.
  • cyclic carbonate may include, but are not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate.
  • EC ethylene carbonate
  • PC propylene carbonate
  • butylene carbonate examples of the cyclic carbonate may include, but are not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate.
  • the cyclic carbonate has 3-6 carbon atoms.
  • chain carbonate may include, but are not limited to, one or more of the following: dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate (DEC), methyl n-propyl carbonate, Chain carbonates such as ethyl n-propyl carbonate and di-n-propyl carbonate.
  • chain carbonates substituted by fluorine may include, but are not limited to, one or more of the following: bis(fluoromethyl)carbonate, bis(difluoromethyl)carbonate, bis(trifluoromethyl) Group) carbonate, bis(2-fluoroethyl) carbonate, bis(2,2-difluoroethyl) carbonate, bis(2,2,2-trifluoroethyl) carbonate, 2-fluoroethyl Methyl carbonate, 2,2-difluoroethyl methyl carbonate and 2,2,2-trifluoroethyl methyl carbonate, etc.
  • cyclic carboxylic acid ester may include, but are not limited to, one or more of the following: one or more of ⁇ -butyrolactone and ⁇ -valerolactone.
  • part of the hydrogen atoms of the cyclic carboxylic acid ester may be substituted by fluorine.
  • Examples of the chain carboxylic acid ester may include, but are not limited to, one or more of the following: methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, sec-butyl acetate , Isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isobutyrate Methyl ester, ethyl isobutyrate, methyl valerate, ethyl valerate, methyl pivalate and ethyl pivalate, etc.
  • part of the hydrogen atoms of the chain carboxylic acid ester may be replaced by fluorine.
  • examples of fluorine-substituted chain carboxylic acid esters may include, but are not limited to, methyl trifluoroacetate, ethyl trifluoroacetate, propyl trifluoroacetate, butyl trifluoroacetate, and trifluoroacetic acid 2,2,2-Trifluoroethyl and so on.
  • Examples of the cyclic ether may include, but are not limited to, one or more of the following: tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 2-methyl 1,3-dioxide Pentane, 4-methyl 1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, and dimethoxypropane.
  • chain ether examples include, but are not limited to, one or more of the following: dimethoxymethane, 1,1-dimethoxyethane, 1,2-dimethoxyethane , Diethoxymethane, 1,1-diethoxyethane, 1,2-diethoxyethane, ethoxymethoxymethane, 1,1-ethoxymethoxyethane and 1,2-Ethoxymethoxyethane and the like.
  • Examples of the phosphorus-containing organic solvent may include, but are not limited to, one or more of the following: trimethyl phosphate, triethyl phosphate, dimethyl ethyl phosphate, methyl diethyl phosphate, phosphite Ethyl methyl ester, ethylene ethyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tris(2,2,2-trifluoroethyl) phosphate And tris (2,2,3,3,3-pentafluoropropyl) phosphate and so on.
  • sulfur-containing organic solvent may include, but are not limited to, one or more of the following: sulfolane, 2-methyl sulfolane, 3-methyl sulfolane, dimethyl sulfone, diethyl sulfone, ethyl Methyl sulfone, methyl propyl sulfone, dimethyl sulfoxide, methyl methanesulfonate, ethyl methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate, dimethyl sulfate, diethyl sulfate and Dibutyl sulfate.
  • part of the hydrogen atoms of the sulfur-containing organic solvent may be replaced by fluorine.
  • the aromatic fluorine-containing solvent includes, but is not limited to, one or more of the following: fluorobenzene, difluorobenzene, trifluorobenzene, tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene and trifluoromethylbenzene .
  • the solvent used in the electrolyte of the present application includes at least one of cyclic carbonate, chain carbonate, cyclic carboxylic acid ester, or chain carboxylic acid ester.
  • the solvent used in the electrolyte of the present application includes ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl propionate, propyl propionate, n-propyl acetate or ethyl acetate. At least one of.
  • the solvent used in the electrolyte of the present application includes at least one of ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl propionate, propyl propionate, or ⁇ -butyrolactone.
  • the electrolyte that can be used in the electrolyte of the embodiments of the present application includes, but is not limited to: inorganic lithium salts, such as LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiSbF 6 , LiSO 3 F, LiN(FSO 2 ) 2, etc.; Fluorine-containing organic lithium salts, such as LiCF 3 SO 3 , LiN(FSO 2 )(CF 3 SO 2 ), LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , cyclic 1,3- Lithium hexafluoropropane disulfonimide, lithium cyclic 1,2-tetrafluoroethane disulfonimide, LiN (CF 3 SO 2 ) (C 4 F 9 SO 2 ), LiC (CF 3 SO 2 ) 3.
  • inorganic lithium salts such as LiClO 4 , LiAsF 6 , LiPF 6 , Li
  • Lithium salt containing dicarboxylic acid complex such as bis(oxalato) lithium borate, difluorooxalic acid Lithium borate, tris(oxalato) lithium phosphate, diflu
  • the electrolyte includes a combination of LiPF 6 and LiBF 4.
  • the electrolyte includes a combination of an inorganic lithium salt such as LiPF 6 or LiBF 4 and a fluorine-containing organic lithium salt such as LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , and LiN(C 2 F 5 SO 2 ) 2 .
  • the concentration of the electrolyte is in the range of 0.8-3 mol/L, for example, in the range of 0.8-2.5 mol/L, in the range of 0.8-2 mol/L, in the range of 1-2 mol/L, for example It is 1mol/L, 1.15mol/L, 1.2mol/L, 1.5mol/L, 2mol/L or 2.5mol/L.
  • the type of the separator is not particularly limited, as long as it is a separator known to be used in electrochemical devices (for example, lithium ion batteries).
  • the isolation membranes that can be used in the embodiments of the present application include polymers or inorganic substances formed of materials that are stable to the electrolyte of the present application.
  • the isolation film may include a substrate layer and a surface treatment layer.
  • the substrate layer is a non-woven fabric, film or composite film with a porous structure, and the material of the substrate layer includes at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyimide.
  • a polypropylene porous film, a polyethylene porous film, a polypropylene non-woven fabric, a polyethylene non-woven fabric, or a polypropylene-polyethylene-polypropylene porous composite film can be selected.
  • a surface treatment layer is provided on at least one surface of the substrate layer.
  • the surface treatment layer may be a polymer layer or an inorganic substance layer, or a layer formed by a mixed polymer and an inorganic substance.
  • the inorganic layer includes inorganic particles and binders.
  • the inorganic particles include aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, and One or a combination of yttrium, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, or barium sulfate.
  • Binders include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, poly One or a combination of methyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the material of the polymer includes polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly( At least one of vinylidene fluoride-hexafluoropropylene).
  • the electrochemical device of the present application includes any device that undergoes an electrochemical reaction, and specific examples thereof include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors.
  • the electrochemical device is a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.
  • the electrochemical device of the present application includes a positive pole piece having a positive active material capable of occluding and releasing metal ions; a negative pole piece according to an embodiment of the present application; an electrolyte; and a positive pole piece placed thereon Separating film between the negative pole piece and the negative pole piece.
  • the electrochemical device of the present application is not particularly limited, and it can be used in any electronic device known in the prior art.
  • the electrochemical device of the present application can be used in, but not limited to, notebook computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, and headsets. Stereo headsets, video recorders, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power assistance Bicycles, bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household storage batteries and lithium-ion capacitors, etc.
  • auxiliary agent with Si-C and Si-O bonds 2000 ppm of the auxiliary agent with Si-C and Si-O bonds was added, and the comparative example did not add the auxiliary agent or 2000 ppm of the auxiliary agent without Si-C and Si-O bonds was added.
  • the auxiliary agents with Si-C and Si-O bonds used in the examples of this application are shown in the following table:
  • Additives Name (trade name) Additive 1 Trisiloxane surfactant (CAS No. 3390-61-2; 28855-11-0) Additive 2 Silicone surfactant (Sylgard 309) Additive 3 Dihydroxy polydimethylsiloxane (PMX-0156) Additive 4 N- ⁇ -Aminoethyl-Y-Aminopropyldimethoxymethylsilane (KH-602) Additive 5 Methyl silicone oil polydimethylsiloxane (CAS No. 63148-62-9)
  • the components are mixed uniformly to obtain a negative electrode slurry.
  • the negative electrode slurry prepared in S1 is coated on a 12 ⁇ m copper foil at a coating speed of 10 m/min to 100 m/min to obtain an initial pole piece.
  • the initial pole piece obtained in S2 is placed in a vacuum drying device for drying, and the drying temperature is 80 to 150° C. to obtain a negative electrode.
  • LiCoO 2 lithium cobaltate
  • Super-P conductive material
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • a polyethylene (PE) porous polymer film is used as the isolation membrane.
  • the obtained positive electrode, separator film and negative electrode are wound in order and placed in the outer packaging foil, leaving a liquid injection port.
  • the electrolyte is poured from the injection port, encapsulated, and then undergoes processes such as chemical conversion and capacity to prepare a lithium-ion battery.
  • a CCD scanner was used to scan and photograph the pole piece after cold pressing, and the grayscale difference at different positions was used to identify defects.
  • the area of 0.2mm 2 and the grayscale difference greater than 10 were regarded as pole piece defects, and the number of defects was counted.
  • Table 1 shows the influence of additives and their order of addition on the surface defects of the negative electrode of lithium-ion batteries.
  • Example 1 In sequence 1, mix additive 1 with carboxymethyl cellulose 10
  • Example 2 Mix additive 1 with deionized water in sequence 2.
  • Example 3 Add additive 1 between sequence 3 and 4 11
  • Example 4 Mix the additive 1 with the binder in sequence 4 2
  • Example 5 Add auxiliary 1 after sequence 4 1
  • Table 2 shows the effects of different additives on the surface defects of the negative electrode of lithium-ion batteries.
  • each auxiliary agent was mixed with deionized water in sequence 2.
  • Comparative Examples 2-4 common organic solvents (for example, ethanol, acetone or ethylene carbonate, which do not have Si-C and Si-O bonds) are added as additives when preparing the negative electrode, and the number of surface defects of the negative electrode is not significant improve.
  • the addition of additives with Si-C and Si-O bonds during the preparation of the negative electrode can significantly reduce the surface tension of the negative electrode slurry and significantly reduce the number of surface defects of the negative electrode.
  • Table 3 shows the effects of coating speed, drying temperature, and vibration treatment on the surface defects of the negative electrode of the lithium ion battery.
  • the adjuvant 1 was mixed with deionized water in the sequence 2.
  • the vibration treatment is ultrasonic treatment after step S2.
  • the results show that when the coating speed is 10 m/min to 100 m/min and the drying temperature is 80° C. to 150° C., the number of surface defects of the negative electrode can be further reduced. When the coating speed is 20 m/min to 100 m/min and the drying temperature is 80° C. to 150° C., the number of surface defects of the negative electrode can be further reduced. Especially after adding vibration treatment, better results can be obtained.
  • references to “embodiments”, “partial examples”, “one embodiment”, “another example”, “examples”, “specific examples” or “partial examples” throughout the specification mean that At least one embodiment or example in this application includes the specific feature, structure, material, or characteristic described in the embodiment or example. Therefore, descriptions appearing in various places throughout the specification, such as: “in some embodiments”, “in embodiments”, “in one embodiment”, “in another example”, “in an example “In”, “in a specific example” or “exemplified”, which are not necessarily quoting the same embodiment or example in this application.
  • the specific features, structures, materials, or characteristics herein can be combined in one or more embodiments or examples in any suitable manner.

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Abstract

一种负极及其制备方法，该制备方法包括添加具有Si-C和Si-O键的助剂的步骤。该制备方法可减少负极表面的缺陷，生产高质量的负极。

Description

负极及其制备方法 技术领域
本申请涉及储能领域，具体涉及一种负极及其制备方法。
背景技术
随着技术的发展和对移动装置的需求的增加，人们对电化学装置(例如，锂离子电池)的需求显著增加。具有高安全性和优异的寿命的电化学装置是研究方向之一。
在电化学装置的负极的制备过程中，负极活性物质、分散剂、粘结剂和导电剂等溶解在溶剂中形成负极浆料。然而，负极活性物质、分散剂、粘结剂和导电剂等通常难以均匀分散，从而造成负极浆料的表面张力不均匀。表面张力的差异会导致缩孔、凹坑或缩边现象，其对负极的表观性能和电化学装置的性能存在不利影响，影响产品的安全性和合格率，进而使生产成本升高。
有鉴于此，确有必要提供一种改进的负极及其制备方法。
发明内容
本申请实施例通过提供一种负极及其制备方法以在至少某种程度上解决至少一种存在于相关领域中的问题。
在本申请的一方面，本申请提供了一种制备负极的方法，其包括添加具有Si-C和Si-O键的助剂的步骤。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂和溶剂混合。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂在添加粘结剂之后再加入。
根据本申请的一些实施例，所述方法包括如下步骤：
S1：混料步骤，其中将负极活性物质、分散剂、粘结剂、溶剂及所述具有Si-C和Si-O键的助剂混合均匀得到负极浆料；
S2：涂布步骤，将S1中制备的所述负极浆料涂覆在负极集流体上，涂覆速度为10米/分钟至100米/分钟，得到初始极片；
S3：干燥步骤，将S2中得到的所述初始极片置于真空干燥设备中进行干燥，干燥温度为80℃至150℃，得到所述负极。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂具有以下特征中的至少一者：
(a)氧化电位不小于4.5V，且还原电位不大于0.5V；和
(b)含0.1％所述具有Si-C和Si-O键的助剂的水溶液的表面张力不大于30mN/m。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂包括聚醚硅氧烷。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂包括复合硅酮聚醚复合物、聚醚改性三硅氧烷或聚醚改性有机硅聚醚硅氧烷中的至少一种。
根据本申请的一些实施例，所述负极活性物质包括然石墨、人造石墨、软碳、硬碳、硅氧、硅碳、硅合金或锡合金中的至少一种。
根据本申请的一些实施例，所述溶剂为去离子水或N-甲基吡咯烷酮。
根据本申请的一些实施例，在S1、S2或S3的任一步骤中同时进行振动处理，所述振动处理为机械振动或超声波振动中的至少一种。
根据本申请的一些实施例，在S1、S2或S3的任一步骤之后进行振动处理，所述振动为机械振动或超声波振动中的至少一种。
根据本申请的一些实施例，所述振动处理的振动频率为100Hz至800Hz，振幅为0.01毫米至0.5毫米，振动时间为1分钟至5分钟。
根据本申请的一些实施例，所述振动处理进行多次，且至少一次所述振动处理的振动频率小于前一次振动处理的振动频率。
在本申请的另一方面，本申请提供一种负极，其通过根据本申请的制备负极的方法获得。
根据本申请的一些实施例，所述负极中所述具有Si-C和Si-O键的助剂的含量为500ppm以下，优选为300ppm以下。
根据本申请的一些实施例，相比不添加具有Si-C和Si-O键的助剂制备的负极，所述负极的表面相对于碳酸二乙酯的接触角减小10％以上。
在本申请的另一方面，本申请提供一种电化学装置，包括正极、负极、隔离膜和电解液，其中所述负极根据本申请的制备负极的方法获得或者所述负极为本申请的负极。
在本申请的另一方面，本申请提供一种电子装置，其包括根据本申请的电化学装置。
本申请实施例的额外层面及优点将部分地在后续说明中描述、显示、或是经由本申请实施例的实施而阐释。
附图说明
在下文中将简要地说明为了描述本申请实施例或现有技术所必要的附图以便于描述本申请的实施例。显而易见地，下文描述中的附图仅只是本申请中的部分实施例。对本领域技术人员而言，在不需要创造性劳动的前提下，依然可以根据这些附图中所例示的结构来获得其他实施例的附图。
图1展示了对比例1的负极的表面外观图。
图2展示了实施例2的负极的表面外观图。
具体实施方式
本申请的实施例将会被详细的描示在下文中。本申请的实施例不应该被解释为对本申请的限制。
除非另外明确指明，本文使用的下述术语具有下文指出的含义。
在具体实施方式及权利要求书中，由术语“中的至少一者”或其他相似术语所连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。术语“中的至少一种”具有与术语“中的至少一者”相同的含义。
在负极的制备过程中，通常将负极活性物质、分散剂、粘结剂和导电剂等溶解在溶剂中形成负极浆料，然后将负极浆料涂覆在负极集流体上，经烘干等步骤后形成负极。由于负极活性物质与溶剂相容性较差，分散剂通常难以充分发挥作用，导致负极活性物质、分散剂、粘结剂和导电剂等通常难以均匀分散在溶剂中，从而使负极浆料不够均匀。不均匀的负极浆料会造成表面张力不均匀。表面张力的差异会导致缩孔、凹坑或缩边现象(如图1所示)，其对负极的表观性能和电化学装置的性能存在不利影响，影响产品的安全性和合格率，进而使生产成本升 高。
本申请通过特定的制备方法改善了负极活性物质和溶剂之间的相容性，进而改善负极浆料的表面张力，减少负极表面的缩孔、凹坑或缩边现象(如图2所示)，从而提高负极质量，改善电化学装置的性能。
1、制备负极的方法
在一个实施例中，本申请提供了一种制备负极的方法，其包括添加具有Si-C和Si-O键的助剂的步骤。
根据本申请的一些实施例，所述方法包括如下步骤：
S1：混料步骤
在该步骤中，负极活性物质、分散剂、粘结剂、溶剂及所述具有Si-C和Si-O键的助剂混合均匀得到负极浆料。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂和溶剂混合。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂在添加粘结剂之后再加入。
根据本申请的一些实施例，所述负极活性物质包括然石墨、人造石墨、软碳、硬碳、硅氧、硅碳、硅合金或锡合金中的至少一种。
根据本申请的一些实施例，所述溶剂为去离子水或N-甲基吡咯烷酮。
根据本申请的一些实施例，所述分散剂包括羧甲基纤维素、羧甲基纤维素衍生物、海藻酸、海藻酸衍生物、聚丙烯酸、聚丙烯酸衍生物、聚酰胺酸、聚酰胺酸衍生物、聚乙烯醇、聚乙烯醇衍生物、淀粉、淀粉衍生物、羟丙基纤维素或羟丙基纤维素衍生物中的至少一种。
根据本申请的一些实施例，所述粘结剂包括丁苯橡胶、聚丙烯酸酯、聚四氟乙烯、聚乙烯醇、聚氨酯、聚偏二氟乙烯、偏二氟乙烯-四氟乙烯共聚物、偏二氟乙烯-六氟丙烯共聚物、六氟丙烯-四氟乙烯共聚物或偏二氟乙烯-四氟乙烯-六氟丙烯共聚物中的至少一种。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂具有以下特征中的至少一者：
(c)氧化电位不小于4.5V，且还原电位不大于0.5V；和
(d)含0.1％所述具有Si-C和Si-O键的助剂的水溶液的表面张力不大于30mN/m。
在一些实施例中，所述具有Si-C和Si-O键的助剂的氧化电位不小于4.5V，且还原电位不大于0.5V。在一些实施例中，所述具有Si-C和Si-O键的助剂的氧化电位不小于5V，且还原电位不大于0.3V。具有上述氧化/还原电位的助剂电化学性能稳定，有助于改善电化学装置的循环和高温存储性能。
在一些实施例中，含0.1wt％所述具有Si-C和Si-O键的助剂的水溶液的表面张力不大于30mN/m。在一些实施例中，含0.1wt％所述具有Si-C和Si-O键的助剂的水溶液的表面张力为不大于25mN/m。在一些实施例中，含0.1wt％所述具有Si-C和Si-O键的助剂的水溶液的表面张力为不大于20mN/m。在一些实施例中，含0.1wt％所述具有Si-C和Si-O键的助剂的水溶液的表面张力为不大于15mN/m。在一些实施例中，含0.1wt％所述具有Si-C和Si-O键的助剂的水溶液的表面张力为不大于10mN/m。当具有Si-C和Si-O键的助剂的表面张力在上述范围内时，负极合剂层的界面良好。
所述具有Si-C和Si-O键的助剂的表面张力可通过如下方法测定：使用JC2000D3E型接触角测量仪对固含量为1％的助剂水溶液进行测试，每个样品至少测试3次，选取至少3个数据，取平均值，得到助剂的表面张力。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂包括聚醚硅氧烷。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂包括复合硅酮聚醚复合物、聚醚改性三硅氧烷或聚醚改性有机硅聚醚硅氧烷中的至少一种。
根据本申请的一些实施例，所述具有Si-C和Si-O键的助剂的加入量为3000ppm以下。在一些实施例中，所述具有Si-C和Si-O键的助剂的加入量为2500ppm以下。在一些实施例中，所述具有Si-C和Si-O键的助剂的加入量为2000ppm以下。在一些实施例中，所述具有Si-C和Si-O键的助剂的加入量为1500ppm以下。在一些实施例中，所述具有Si-C和Si-O键的助剂的加入量为1000ppm以下。在一些实施例中，所述具有Si-C和Si-O键的助剂的加入量为500ppm以下。当具有Si-C和Si-O键的助剂的加入量在上述范围内时，可有效地降低负极浆料的表面张力。
在该步骤中所添加的负极活性物质、分散剂、粘结剂、溶剂和具有Si-C和Si-O键的助剂比例不受特别限制，只要是已知在负极浆料的制备过程中可采用的比例即可。
S2：涂布步骤
在该步骤中，将S1中制备的所述负极浆料涂覆在负极集流体上，涂覆速度为10米/分钟至100米/分钟，得到初始极片。
S3：干燥步骤
在该步骤中，将S2中得到的所述初始极片置于真空干燥设备中进行干燥，干燥温度为80℃至150℃，得到所述负极。
根据本申请的一些实施例，在S1、S2或S3的任一步骤中同时进行振动处理，所述振动处理为机械振动或超声波振动中的至少一种。根据本申请的一些实施例，在S1、S2或S3的任一步骤之后进行振动处理，所述振动为机械振动或超声波振动中的至少一种。振动处理可有效地防止负极浆料因密度差异而产生的不均匀。
根据本申请的一些实施例，所述振动处理的振动频率为100Hz至800Hz，振幅为0.01毫米至0.5毫米，振动时间为1分钟至5分钟。
根据本申请的一些实施例，所述振动处理进行多次，且至少一次所述振动处理的振动频率小于前一次振动处理的振动频率。
2、负极
在另一个实施例中，本申请提供一种负极，其通过根据本申请的制备负极的方法获得。
根据本申请的一些实施例，所述负极中所述具有Si-C和Si-O键的助剂的含量为500ppm以下。在一些实施例中，所述负极中所述具有Si-C和Si-O键的助剂的含量为400ppm以下。在一些实施例中，所述负极中所述具有Si-C和Si-O键的助剂的含量为300ppm以下。在一些实施例中，所述负极中所述具有Si-C和Si-O键的助剂的含量为200ppm以下。
根据本申请的一些实施例，相比不添加具有Si-C和Si-O键的助剂制备的负极(接触角大70°)，所述负极的表面相对于碳酸二乙酯的接触角减小10％以上。
接触角是指在将碳酸二乙酯的液滴滴在负极合剂层上后10秒内测量的接触角。碳酸二乙酯是常用的电解液溶剂。使用碳酸二乙酯作为接触角的测试指标，可以检验电解液进入负极合剂层的浸润性。负极的表面相对于碳酸二乙酯的接触角变小可说明电解液进入负极合剂层的浸渍性提高，且负极合剂层的液体保持特性增强。
接触角可以通过由Kyowa Interface Science Co.，Ltd.制备的自动接触角测量 计等进行测量。接触角θ可通过例如θ/2法来确定，即，在液滴基线与超过液滴顶点的线之间的角度限定为θ′的情况下，接触角θ＝2θ′成立。根据该内容，接触角θ可通过利用液滴基线的距离2r和液滴的高度h测量θ′来计算。此时，有必要使液滴以达到不受重力影响的程度的量滴落。接触角测试使用的非水溶剂可以选用碳酸二乙酯、碳酸甲乙酯、碳酸二甲酯、碳酸甲丙酯或碳酸甲异丙酯等常用电解液溶剂。
根据本申请的一些实施例，所述负极活性物质层相对非水溶剂的接触角不大于60°。在一些实施例中，经接触角测定法测定，所述负极活性物质层相对非水溶剂的接触角不大于50°。在一些实施例中，经接触角测定法测定，所述负极活性物质层相对非水溶剂的接触角不大于30°。当负极活性物质层相对非水溶剂具有如上所述的接触角时，负极活性物质层界面具有较少缺陷，在电化学装置的充放电循环中稳定性良好，可保证电化学装置的循环性能。
3、正极
正极、隔离膜和电解液不受特别限制，只要是已知可用于电化学装置(例如，锂离子电池)的正极、隔离膜和电解液即可。
可用于本申请实施例的正极包括正极集流体和位于正极集流体上的正极活性物质层。正极活性物质的种类不受特别限制，只要是已知可用于电化学装置(例如，锂离子电池)的正极活性物质即可，例如含锂的化合物，其可为电化学装置提供高能量密度。所述含锂的化合物包括锂过渡金属复合氧化物和锂过渡金属磷酸盐化合物中的一种或多种。所述锂过渡金属复合氧化物包含锂和具有一种或多种过渡金属元素的氧化物。所述锂过渡金属磷酸盐化合物是包含锂和具有一种或多种过渡金属元素的磷酸盐化合物。所述过渡金属元素包含Co、Ni、Mn和Fe中的一种或多种，这些元素可使电化学装置获得更高的电压。所述含锂的化合物具有化学式LixM1O 2或LiyM2PO 4，其中M1和M2表示一种或多种过渡金属元素，x和y的值随充电/放电状态而变化，且通常在以下范围内：0.05≤x≤1.10和0.05≤y≤1.10。在一些实施例中，所述锂过渡金属复合氧化物包括，但不限于，LiCoO 2、LiNiO 2和由式LiNi 1-zMzO 2表示的锂镍基过渡金属复合氧化物，其中M选自Co、Mn、Fe、Al、V、Sn、Mg、Ti、Sr、Ca、Zr、Mo、Tc、Ru、Ta、W、Re、Yb、Cu、Zn、Ba、B、Cr、Si、Ga、P、Sb和Nb中的一种或多种，且z满足0.005<z<0.5。在一些实施例中，所述锂过渡金属磷酸盐化合物包括，但不限 于，LiFePO 4和由式LiFe 1-uMn uPO 4表示的化合物，其中u<1。采用这些化合物作为正极的活性物质，所得到的电化学装置具有高电池容量和优异的循环特性。
4、电解液
电解液的种类不受特别限制，只要是已知可用于电化学装置(例如，锂离子电池)的电解液即可。
所述电解液包含现有技术中已知的任何可作为电解液的溶剂的非水溶剂。所述非水溶剂包括，但不限于，以下中的一种或多种：环状碳酸酯、链状碳酸酯、环状羧酸酯、链状羧酸酯、环状醚、链状醚、含磷有机溶剂、含硫有机溶剂和芳香族含氟溶剂。
所述环状碳酸酯的实例可包括，但不限于，以下中的一种或多种：碳酸亚乙酯(EC)、碳酸亚丙酯(PC)和碳酸亚丁酯。在一些实施例中，所述环状碳酸酯具有3-6个碳原子。
所述链状碳酸酯的实例可包括，但不限于，以下中的一种或多种：碳酸二甲酯、碳酸甲乙酯、碳酸二乙酯(DEC)、碳酸甲基正丙基酯、碳酸乙基正丙基酯、碳酸二正丙酯等链状碳酸酯等。被氟取代的链状碳酸酯的实例可包括，但不限于，以下中的一种或多种：双(氟甲基)碳酸酯、双(二氟甲基)碳酸酯、双(三氟甲基)碳酸酯、双(2-氟乙基)碳酸酯、双(2，2-二氟乙基)碳酸酯、双(2，2，2-三氟乙基)碳酸酯、2-氟乙基甲基碳酸酯、2，2-二氟乙基甲基碳酸酯和2，2，2-三氟乙基甲基碳酸酯等。
所述环状羧酸酯的实例可包括，但不限于，以下中的一种或多种：γ-丁内酯和γ-戊内酯中的一种或多种。在一些实施例中，环状羧酸酯的部分氢原子可被氟取代。
所述链状羧酸酯的实例可包括，但不限于，以下中的一种或多种：乙酸甲酯、乙酸乙酯、乙酸丙酯、乙酸异丙酯、乙酸丁酯、乙酸仲丁酯、乙酸异丁酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丙酸异丙酯、丁酸甲酯、丁酸乙酯、丁酸丙酯、异丁酸甲酯、异丁酸乙酯、戊酸甲酯、戊酸乙酯、特戊酸甲酯和特戊酸乙酯等。在一些实施例中，链状羧酸酯的部分氢原子可被氟取代。在一些实施例中，氟取代的链状羧酸酯的实例可包括，但不限于，三氟乙酸甲酯、三氟乙酸乙酯、三氟乙酸丙酯、三氟乙酸丁酯和三氟乙酸2，2，2-三氟乙酯等。
所述环状醚的实例可包括，但不限于，以下中的一种或多种：四氢呋喃、2- 甲基四氢呋喃、1，3-二氧戊环、2-甲基1，3-二氧戊环、4-甲基1，3-二氧戊环、1，3-二氧六环、1，4-二氧六环和二甲氧基丙烷。
所述链状醚的实例可包括，但不限于，以下中的一种或多种：二甲氧基甲烷、1，1-二甲氧基乙烷、1，2-二甲氧基乙烷、二乙氧基甲烷、1，1-二乙氧基乙烷、1，2-二乙氧基乙烷、乙氧基甲氧基甲烷、1，1-乙氧基甲氧基乙烷和1，2-乙氧基甲氧基乙烷等。
所述含磷有机溶剂的实例可包括，但不限于，以下中的一种或多种：磷酸三甲酯、磷酸三乙酯、磷酸二甲基乙酯、磷酸甲基二乙酯、磷酸亚乙基甲酯、磷酸亚乙基乙酯、磷酸三苯酯、亚磷酸三甲酯、亚磷酸三乙酯、亚磷酸三苯酯、磷酸三(2，2，2-三氟乙基)酯和磷酸三(2，2，3，3，3-五氟丙基)酯等。
所述含硫有机溶剂的实例可包括，但不限于，以下中的一种或多种：环丁砜、2-甲基环丁砜、3-甲基环丁砜、二甲基砜、二乙基砜、乙基甲基砜、甲基丙基砜、二甲基亚砜、甲磺酸甲酯、甲磺酸乙酯、乙磺酸甲酯、乙磺酸乙酯、硫酸二甲酯、硫酸二乙酯和硫酸二丁酯。在一些实施例中，含硫有机溶剂的部分氢原子可被氟取代。
所述芳香族含氟溶剂包括，但不限于，以下中的一种或多种：氟苯、二氟苯、三氟苯、四氟苯、五氟苯、六氟苯和三氟甲基苯。
在一些实施例中，本申请的电解液中使用的溶剂包括环状碳酸酯、链状碳酸酯、环状羧酸酯或链状羧酸酯中的至少一种。在一些实施例中，本申请的电解液中使用的溶剂包含碳酸亚乙酯、碳酸亚丙酯、碳酸二乙酯、丙酸乙酯、丙酸丙酯、乙酸正丙酯或乙酸乙酯中的至少一种。在一些实施例中，本申请的电解液中使用的溶剂包含碳酸亚乙酯、碳酸亚丙酯、碳酸二乙酯、丙酸乙酯、丙酸丙酯或γ-丁内酯中的至少一种。
可用于本申请实施例的电解液中的电解质包括、但不限于：无机锂盐，例如LiClO 4、LiAsF 6、LiPF 6、LiBF 4、LiSbF 6、LiSO 3F、LiN(FSO 2) 2等；含氟有机锂盐，例如LiCF 3SO 3、LiN(FSO 2)(CF 3SO 2)、LiN(CF 3SO 2) 2、LiN(C 2F 5SO 2) 2、环状1，3-六氟丙烷二磺酰亚胺锂、环状1，2-四氟乙烷二磺酰亚胺锂、LiN(CF 3SO 2)(C 4F 9SO 2)、LiC(CF 3SO 2) 3、LiPF 4(CF 3) 2、LiPF 4(C 2F 5) 2、LiPF 4(CF 3SO 2) 2、LiPF 4(C 2F 5SO 2) 2、LiBF 2(CF 3) 2、LiBF2(C2F5)2、LiBF 2(CF 3SO 2) 2、LiBF 2(C 2F 5SO 2) 2；含二羧酸配合物锂盐，例如双(草酸根合)硼酸锂、二氟草酸根合硼酸锂、三(草酸 根合)磷酸锂、二氟双(草酸根合)磷酸锂、四氟(草酸根合)磷酸锂等。另外，上述电解质可以单独使用一种，也可以同时使用两种或两种以上。例如，在一些实施例中，电解质包括LiPF 6和LiBF 4的组合。在一些实施例中，电解质包括LiPF 6或LiBF 4等无机锂盐与LiCF 3SO 3、LiN(CF 3SO 2) 2、LiN(C 2F 5SO 2) 2等含氟有机锂盐的组合。在一些实施例中，电解质的浓度在0.8-3mol/L的范围内，例如0.8-2.5mol/L的范围内、0.8-2mol/L的范围内、1-2mol/L的范围内、又例如为1mol/L、1.15mol/L、1.2mol/L、1.5mol/L、2mol/L或2.5mol/L。
5、隔离膜
隔离膜的种类不受特别限制，只要是已知可用于电化学装置(例如，锂离子电池)的隔离膜即可。
可用于本申请实施例的隔离膜包括由对本申请的电解液稳定的材料形成的聚合物或无机物等。例如，隔离膜可包括基材层和表面处理层。基材层为具有多孔结构的无纺布、膜或复合膜，基材层的材料包括聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰亚胺中的至少一种。具体的，可选用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。
基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。
无机物层包括无机颗粒和粘结剂，无机颗粒包括氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙或硫酸钡中的一种或几种的组合。粘结剂包括聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯或聚六氟丙烯中的一种或几种的组合。
聚合物层中包含聚合物，聚合物的材料包括聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯或聚(偏氟乙烯-六氟丙烯)中的至少一种。
6、电化学装置
本申请的电化学装置包括发生电化学反应的任何装置，它的具体实例包括所有种类的一次电池、二次电池、燃料电池、太阳能电池或电容。特别地，该电化学装置是锂二次电池，包括锂金属二次电池、锂离子二次电池、锂聚合物二次电 池或锂离子聚合物二次电池。在一些实施例中，本申请的电化学装置包括具有能够吸留、放出金属离子的正极活性物质的正极极片；根据本申请的实施例的负极极片；电解液；和置于正极极片和负极极片之间的隔离膜。
7、电子装置
本申请的电化学装置的用途没有特别限定，其可用于现有技术中已知的任何电子装置。在一个实施例中，本申请的电化学装置可用于，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
下面以锂离子电池为例并且结合具体的实施例说明锂离子电池的制备，本领域的技术人员将理解，本申请中描述的制备方法仅是实例，其他任何合适的制备方法均在本申请的范围内。
实施例
下文将结合实施例和对比例更具体地描述本申请的实施方案。然而，本申请的实施方案不仅仅限于这些实施例。
一、锂离子电池的制备
1、负极的制备
S1：混料步骤
将人造石墨、丁苯橡胶和羧甲基纤维素按照质量比例96％∶3％∶1％与去离子水混合，其添加顺序为：
1.人造石墨和羧甲基纤维素
2.去离子水
3.羧甲基纤维素
4.丁苯橡胶
根据以下实施例加入2000ppm具有Si-C和Si-O键的助剂，对比例不加助剂或加入2000ppm不具有Si-C和Si-O键的助剂。本申请实施例中使用的具有Si-C和Si-O键的助剂如下表所示：
助剂 名称(商品名)
助剂1 三硅氧烷表面活性剂(CAS No.3390-61-2；28855-11-0)
助剂2 有机硅表面活性剂(Sylgard 309)
助剂3 二羟基聚二甲基硅氧烷(PMX-0156)
助剂4 N-β-氨乙基-Y-氨丙基二甲氧基甲基硅烷(KH-602)
助剂5 甲基硅油聚二甲基硅氧烷(CAS No.63148-62-9)
将各组分混合均匀，得到负极浆料。
S2：涂布步骤
将S1中制备的负极浆料涂覆在12μm的铜箔上，涂覆速度为10米/分钟至100米/分钟，得到初始极片。
S3：干燥步骤
将S2中得到的初始极片置于真空干燥设备中进行干燥，干燥温度为80至150℃，得到负极。
2、正极的制备
将钴酸锂(LiCoO 2)、导电材料(Super-P)和聚偏氟乙烯(PVDF)按照95％∶2％∶3％的质量比例与N-甲基吡咯烷酮(NMP)混合，搅拌均匀，得到正极浆料。将该正极浆料涂布在12μm的铝箔上，干燥，冷压，再经过裁片、焊接极耳，得到正极。
3、电解液的制备
在干燥氩气环境下，将EC、PC和DEC(重量比1∶1∶1)混合，加入LiPF 6混合均匀，得到电解液，其中LiPF 6的浓度为1.15mol/L。
4、隔离膜的制备
以聚乙烯(PE)多孔聚合物薄膜作为隔离膜。
5、锂离子电池的制备
将得到的正极、隔离膜和负极按次序卷绕，置于外包装箔中，留下注液口。从注液口灌注电解液，封装，再经过化成、容量等工序制得锂离子电池。
二、锂离子电池的负极表面缺陷测试方法
利用CCD扫描仪对冷压后极片进行扫描拍照，利用不同位置的灰度差识别缺陷，将0.2mm 2面积、灰度差大于10视为极片缺陷，统计缺陷个数。
三、测试结果
表1展示了助剂及其添加顺序对锂离子电池的负极表面缺陷的影响。
表1
  助剂及其加入顺序 负极表面缺陷个数/10m 2
对比例1 不加助剂 20
实施例1 在顺序1中使助剂1与羧甲基纤维素混合 10
实施例2 在顺序2中使助剂1与去离子水混合 1
实施例3 在顺序3和4之间加入助剂1 11
实施例4 在顺序4中使助剂1与粘结剂混合 2
实施例5 在顺序4之后加入助剂1 1
如对比例1所示，在制备负极时不添加助剂，所得负极表面缺陷数较多。如实施例1-5所示，在制备负极时添加具有Si-C和Si-O键的助剂可显著改善负极浆料的表面张力，从而显著减少负极表面缺陷数。在制备负极时添加助剂，使具有Si-C和Si-O键的助剂与溶剂混合、使具有Si-C和Si-O键的助剂与粘结剂混合或在添加粘结剂之后再加入具有Si-C和Si-O键的助剂，负极表面缺陷数极少。图1和图2分别为对比例1和实施例2所制得的极片，图1中明显色差的位置(例如，图1中黑色圆圈所标示的位置)即为极片缺陷处，图2中几乎看不到色差斑点。
表2展示了不同助剂对锂离子电池的负极表面缺陷的影响。在表2的实施例中，各助剂在顺序2中与去离子水混合。
表2
  助剂 负极表面缺陷个数/10m 2
对比例2 乙醇 18
对比例3 丙酮 16
对比例4 碳酸乙烯酯 15
实施例2 助剂1 1
实施例6 助剂2 1.2
实施例7 助剂3 1.1
实施例8 助剂4 0.9
实施例9 助剂5 0.8
如对比例2-4所示，在制备负极时添加常用有机溶剂(例如，乙醇、丙酮或碳酸乙烯酯，其不具有Si-C和Si-O键)作为助剂，负极表面缺陷数没有显著改善。如实施例2和6-9所示，在制备负极时添加具有Si-C和Si-O键的助剂可显著降低负极浆料的表面张力，显著减少负极表面缺陷数。
表3展示了涂布速度、干燥温度和振动处理对锂离子电池的负极表面缺陷的影响。在表3的实施例中，使助剂1在顺序2中与去离子水混合。振动处理是在 S2步骤后进行超声波处理。
表3
Figure PCTCN2019128441-appb-000001
结果表明，当涂覆速度为10米/分钟至100米/分钟且干燥温度为80℃至150℃时，可进一步降低负极表面缺陷数。在涂覆速度为20米/分钟至100米/分钟且干燥温度为80℃至150℃，可更进一步降低负极表面缺陷数。尤其在增加振动处理后，可获得更好的效果。
整个说明书中对“实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用，其所代表的意思是在本申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此，在整个说明书中的各处所出现的描述，例如：“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”，“在一个举例中”、“在特定举例中”或“举例“，其不必然是引用本申请中的相同的实施例或示例。此外，本文中的特定特征、结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (18)

  1. 一种制备负极的方法，其包括添加具有Si-C和Si-O键的助剂的步骤。
  2. 根据权利要求1所述的制备负极的方法，其中所述具有Si-C和Si-O键的助剂和溶剂混合。
  3. 根据权利要求1所述的制备负极的方法，其中所述具有Si-C和Si-O键的助剂在添加粘结剂之后再加入。
  4. 根据权利要求1所述的制备负极的方法，其包括如下步骤：
    S1：混料步骤，其中将负极活性物质、分散剂、粘结剂、溶剂及所述具有Si-C和Si-O键的助剂混合均匀得到负极浆料；
    S2：涂布步骤，将S1中制备的所述负极浆料涂覆在负极集流体上，涂覆速度为10米/分钟至100米/分钟，得到初始极片；
    S3：干燥步骤，将S2中得到的所述初始极片置于真空干燥设备中进行干燥，干燥温度为80℃至150℃，得到所述负极。
  5. 根据权利要求1所述的制备负极的方法，其中所述具有Si-C和Si-O键的助剂具有以下特征中的至少一者：
    (a)氧化电位不小于4.5V，且还原电位不大于0.5V；和
    (b)含0.1％所述具有Si-C和Si-O键的助剂的水溶液的表面张力不大于30mN/m。
  6. 根据权利要求1所述的制备负极的方法，其中所述具有Si-C和Si-O键的助剂包括聚醚硅氧烷，优选包括复合硅酮聚醚复合物、聚醚改性三硅氧烷或聚醚改性有机硅聚醚硅氧烷中的至少一种。
  7. 根据权利要求1所述的制备负极的方法，其中所述具有Si-C和Si-O键的助剂的加入量为3000ppm以下。
  8. 根据权利要求4所述的制备负极的方法，所述负极活性物质包括然石墨、人造石墨、软碳、硬碳、硅氧、硅碳、硅合金或锡合金中的至少一种。
  9. 根据权利要求2所述的制备负极的方法，所述溶剂为去离子水或N-甲基吡咯烷酮。
  10. 根据权利要求4所述的制备负极的方法，其中在S1、S2或S3的任一步 骤中同时进行振动处理，所述振动处理为机械振动或超声波振动中的至少一种。
  11. 根据权利要求4所述的制备负极的方法，其中在S1、S2或S3的任一步骤之后进行振动处理，所述振动为机械振动或超声波振动中的至少一种。
  12. 根据权利要求10或11所述的制备负极的方法，其中所述振动处理的振动频率为100Hz至800Hz，振幅为0.01毫米至0.5毫米，振动时间为1分钟至5分钟。
  13. 根据权利要求10或11所述的制备负极的方法，其中所述振动处理进行多次，且至少一次所述振动处理的振动频率小于前一次振动处理的振动频率。
  14. 一种负极，其通过根据权利要求1至13中任一项所述的制备负极的方法获得。
  15. 根据权利要求14所述的负极，其中所述负极中所述具有Si-C和Si-O键的助剂的含量为500ppm以下，优选为300ppm以下。
  16. 根据权利要求14所述的负极，其中相比不添加具有Si-C和Si-O键的助剂制备的负极，所述负极的表面相对于碳酸二乙酯的接触角减小10％以上。
  17. 一种电化学装置，其包括正极、负极、隔离膜和电解液，其中所述负极根据权利要求1至13中任一项所述的制备负极的方法获得或者所述负极为根据权利要求14至16中任一项所述的负极。
  18. 一种电子装置，其包括根据权利要求17所述的电化学装置。
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