WO2022193498A1 - Method for preparing high-initial-coulombic-efficiency sio/graphite composite negative electrode material - Google Patents

Method for preparing high-initial-coulombic-efficiency sio/graphite composite negative electrode material Download PDF

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WO2022193498A1
WO2022193498A1 PCT/CN2021/105896 CN2021105896W WO2022193498A1 WO 2022193498 A1 WO2022193498 A1 WO 2022193498A1 CN 2021105896 W CN2021105896 W CN 2021105896W WO 2022193498 A1 WO2022193498 A1 WO 2022193498A1
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sio
graphite
negative electrode
electrode material
composite negative
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PCT/CN2021/105896
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French (fr)
Chinese (zh)
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黄建根
单沈桃
苏敏
朱丹凤
李慧
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万向一二三股份公司
万向集团公司
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Publication of WO2022193498A1 publication Critical patent/WO2022193498A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to the technical field of battery preparation, in particular to a preparation method of a high first-efficiency SiO-graphite composite negative electrode material.
  • the negative electrode material of lithium battery is one of the key factors that determine the performance of lithium battery such as charge-discharge efficiency and cycle life.
  • commercial lithium batteries mainly use graphite as the negative electrode material.
  • the specific capacity of high-end graphite materials on the market has reached 360-365mAh/g, which is close to the theoretical specific capacity of graphite (372mAh/g). Therefore, graphite is used as the negative electrode material.
  • the energy density of lithium batteries is limited and cannot meet the high energy density requirements of power batteries.
  • SiO material has a high capacity (2600mAh/g), the volume change during cycling is smaller than that of Si material, and the irreversible formation of lithium oxide and lithium silicate during the first charge and discharge process can play a buffer role in the cycle process, and the cycle performance is better than that of Si material.
  • Si material is good, making it one of the alternatives for commercial graphite anodes.
  • the SiO material will have a large volume expansion during the lithium intercalation process, which will destroy the conductive network. During the cycle process, the material is prone to pulverization, which will cause the battery capacity to decay rapidly; and the intrinsic conductivity of SiO is much lower than that of graphite.
  • Severe electrode polarization occurs during discharge; during the charge-discharge process, the Coulombic efficiency decreases due to the continuous consumption of Li + due to the formation of the solid electrolyte interfacial film (SEI).
  • SEI solid electrolyte interfacial film
  • a new method is proposed in patent CN 109037636 A, the content of which is: 1) Weigh SiO and sanding medium in a mass ratio of (1 ⁇ 5):10 and place them in a sand mill tank, and add auxiliary After the abrasives are mixed, sanding is carried out to nanosize the SiO to obtain a SiO suspension 2) After the suspension of SiO and the inorganic carbon source is uniformly dispersed, spray-drying and granulation is performed to obtain the SiO powder coated with the carbon source; 3) The SiO powder is coated with the carbon source; The SiO powder coated with the carbon source is placed in a tube furnace and calcined at a high temperature in an atmosphere of an inert gas, and then naturally cooled to room temperature to obtain a SiO/carbon composite material; 4) Weigh the obtained SiO/carbon composite material in a mass ratio of 10:100.
  • the SiO/carbon composite material and graphite are added, and a ball milling medium is added for ball milling, and the SiO/carbon composite material and graphite are mixed uniformly and taken out to obtain a SiO/carbon/graphite composite negative electrode material.
  • a ball milling medium is added for ball milling, and the SiO/carbon composite material and graphite are mixed uniformly and taken out to obtain a SiO/carbon/graphite composite negative electrode material.
  • the preparation process of nano-sized SiO is complicated and the cost is high, which is not conducive to commercialization, and the nano-sized SiO is bonded together to form large particles through spray drying, which cannot play the role of nano-sized, and there is still huge stress during the expansion process.
  • the composite material of graphite and SiO realized by the ball milling method because the particles are physically aggregated together, the bonding force is not strong, and it is easy to separate during the cycle process and cannot achieve the effect of relieving volume expansion. Accordingly, an ideal solution is required.
  • the present invention provides a preparation method of a high first-efficiency SiO-graphite composite negative electrode material, wherein SiO is embedded between graphite and graphite and bonded together by a carbon source,
  • the volume expansion and pulverization of SiO are effectively limited by the graphite in the outer layer, and the first Coulomb efficiency and cycle stability of the negative electrode material are greatly improved by the Li salt.
  • the preparation process of the method is simple, and the cost is low, which is beneficial to mass production.
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material comprising the following steps:
  • SiO, carbon source and Li salt are uniformly mixed and heated to melt the carbon source, so that SiO particles and Li salt are reacted and uniformly dispersed in the carbon source; It is compounded with graphite for high-temperature carbonization, so that the carbon source is remelted and the SiO particles are bonded to the surface of the graphite particles.
  • the surfaces of SiO and graphite are both covered by carbon layers. Since the particle size of SiO is smaller than that of graphite, SiO is uniformly dispersed between graphites during the granulation process, forming a structure in which SiO is sandwiched between graphite and graphite. Effectively limit the volume expansion and pulverization of SiO.
  • the method has simple preparation process, low cost and good reproducibility, and is suitable for large-scale commercial production applications.
  • the particle size of the SiO in step (1) is 0.5-5 ⁇ m.
  • the organic carbon source described in step (1) is one of glucose, citric acid, pitch, polyvinylpyrrolidone, polyethylene glycol, sucrose, polyvinyl alcohol, polyacrylic acid, polyvinyl chloride and phenolic resin or several.
  • the organic carbon source is citric acid, and the citric acid is modified, and the specific operations are:
  • citric acid of branch 1) Disperse citric acid in deionized water, add titanium dioxide under stirring so that the concentration of titanium dioxide in the system is 180-300g/L, the mass of citric acid is 0.05-0.1% of the titanium dioxide, wet ball milling for 20-30min, and dry to obtain a titanium dioxide connection. citric acid of branch;
  • citric acid and polyethylene oxide grafted by titanium dioxide are respectively dissolved in dimethyl sulfoxide to obtain a solution, and the citric acid solution grafted by titanium dioxide is dropped by the mol ratio (3-7) of citric acid and polyethylene oxide: 10 Add it to the polyethylene oxide solution, heat and stir at 60-100 ° C for 3-5 hours, the reaction solution is cooled and added dropwise to the ethanol solution of NaOH to precipitate a solid, and the solid is washed and dried to obtain modified citric acid.
  • the grafted titanium dioxide has better dispersibility and stability than the directly added composite titanium dioxide particles.
  • citric acid and polyethylene oxide are reacted to form a cross-linked network structure, which can form a protective layer and separate SiO from the electrolyte.
  • the reaction of citric acid and polyethylene oxide can improve the mechanical properties of polyethylene oxide, and citric acid plays a supporting role, which can inhibit the volume expansion of SiO.
  • the Li salt in step (1) is one or more of LiH, LiOH and n-butyllithium.
  • the graphite in step (1) is one or more of artificial graphite, natural graphite and expanded graphite.
  • the granulation equipment described in step (2) is a spray granulator, a VC coating machine, a vertical granulation kettle or a horizontal granulation kettle.
  • the granulation process described in step (2) is as follows: first, the temperature is raised to 200-500°C at a rate of 3-10°C/min for 30-60min, and then heated to 600°C at a rate of 3-10°C/min. -800°C for 1-3h.
  • the high-temperature calcination process in step (3) is as follows: the temperature is raised to 800-1100° C. at a rate of 3-10° C./min, and the temperature is kept for 1-3 hours.
  • the inert gas is one or more of helium, argon and nitrogen.
  • the present invention has the following beneficial effects:
  • SiO is uniformly dispersed between graphites, forming a structure in which SiO is sandwiched between graphite and graphite, and effectively limiting the volume expansion and pulverization of SiO through the graphite of the outer layer;
  • the present invention modifies the organic carbon source citric acid to further limit the volume expansion and pulverization problems of SiO;
  • the method of the present invention is simple in preparation process, low in cost and good in reproducibility, and is suitable for large-scale commercial production applications.
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material comprising the following steps:
  • the composite material B was transferred to a box furnace and heated to 900°C at a heating rate of 5°C/min, maintained for 2 hours and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material comprising the following steps:
  • the composite material B was transferred to a box furnace and heated to 1000°C at a heating rate of 5°C/min, maintained for 2 hours and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material comprising the following steps:
  • the composite material B was transferred to a box furnace and heated to 1000°C at a heating rate of 5°C/min, maintained for 2 hours and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material comprising the following steps:
  • the composite material B was transferred to a box furnace and heated to 1100°C at a heating rate of 10°C/min, kept for 1 hour and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material the difference from Example 4 is that citric acid is modified, and the specific operations are:
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material the difference from Example 4 is that citric acid is modified, and the specific operations are:
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material the difference from Example 4 is that citric acid is modified, and the specific operations are:
  • a preparation method of a high first-efficiency SiO graphite composite negative electrode material comprising the following steps:
  • the mixed material is transferred to the vertical granulation kettle by vacuum equipment and passed into an inert atmosphere, the stirring speed is 100 rev/min, and the temperature rise rate of 3 °C/min is raised to 300 °C and kept for 1 hour, and then with The heating rate of 5°C/min was raised to 700°C for 2 hours, and after natural cooling, a carbon source-coated and bonded graphite material D was obtained;
  • the SiO/graphite composite negative electrode materials prepared in Examples 1-5 and Comparative Example 1 were subjected to preparation of pole pieces, assembly of button batteries and tests of electrochemical performance.
  • the concrete steps are as follows: the SiO/graphite composite negative electrode material prepared by Examples 1-5 and Comparative Example 1 is mixed with conductive carbon black, sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) by mass 90:5: Mix at 2:3, add deionized water as a solvent for stirring; after stirring evenly, use coating equipment to evenly coat on the copper foil current collector, bake in a vacuum drying oven at 90 °C for 24 hours, and then press evenly by a roller machine , and finally use a punching machine to form a circular pole piece with a diameter of 14mm; then use a metal lithium plate as the counter electrode, the diaphragm is a polypropylene film (Celgard 2300), and the electrolyte is 1mol/L lithium hexafluorophosphate and
  • test results are shown in the following table. During the test, charge-discharge cycles were performed at a rate of 0.1C (1C was calculated as 500mAh/g), the voltage range was 0-1.5V, and the number of cycles was 100 times. The battery after 100 cycles was disassembled to measure the expansion rate of the pole piece.

Abstract

The present invention relates to the technical field of battery preparation, and regarding the problem that a SiO material and graphite are difficult to disperse uniformly upon mixing, provides a method for preparing a high-initial-Coulombic-efficiency SiO/graphite composite negative electrode material, comprising the following steps: 1) uniformly mixing SiO, graphite, an organic carbon source, and a Li salt to obtain a mixture A, wherein the particle size of the SiO is less than that of the graphite; 2) granulating the mixture A to obtain a SiO/graphite composite material precursor B; and 3) calcinating the composite material precursor B in an inert gas atmosphere and cooling same to obtain a carbon-coated SiO/graphite composite negative electrode material. According to the present invention, the SiO is embedded between the graphite and graphite and bonded together by means of the carbon source, such that the problems of volume expansion and pulverization of the SiO are effectively limited by means of graphite in an outer layer, and the initial Coulombic efficiency and cycling stability of the negative electrode material are greatly improved by means of the Li salt. Moreover, the method has a simple preparation process and low costs, facilitating mass production.

Description

一种高首效SiO石墨复合负极材料的制备方法A kind of preparation method of high first-efficiency SiO graphite composite negative electrode material 技术领域technical field
本发明涉及电池制备技术领域，尤其是涉及一种高首效SiO石墨复合负极材料的制备方法。The invention relates to the technical field of battery preparation, in particular to a preparation method of a high first-efficiency SiO-graphite composite negative electrode material.
背景技术Background technique
锂电池的负极材料是决定锂电池的充放电效率、循环寿命等性能的关键因素之一。目前，商业化的锂电池主要以石墨为负极材料，市场上高端石墨材料的比容量已达到360-365mAh/g，接近于石墨的理论比容量(372mAh/g)，因此以石墨作为负极材料的锂电池能量密度的提升空间有限，无法满足动力电池高能量密度的要求。SiO材料由于具有高容量(2600mAh/g)、循环过程中的体积变化小于Si材料、首次充放电过程中不可逆形成的氧化锂和硅酸锂在循环过程中可起到缓冲作用，且循环性能比Si材料好，使其成为商业化石墨负极的替代产品之一。但SiO材料在嵌锂过程中会产生较大的体积膨胀，破坏导电网络，循环过程中材料易发生粉化，使电池容量快速衰减；且SiO的固有电导率远低于石墨，在大电流充放电时会产生严重的电极极化；在充放电过程中，由于固体电解质界面膜(SEI)的生成不断消耗Li +，导致库伦效率降低。SiO材料作为负极材料相比于石墨明显偏低，对于电芯的容量增加不明显。 The negative electrode material of lithium battery is one of the key factors that determine the performance of lithium battery such as charge-discharge efficiency and cycle life. At present, commercial lithium batteries mainly use graphite as the negative electrode material. The specific capacity of high-end graphite materials on the market has reached 360-365mAh/g, which is close to the theoretical specific capacity of graphite (372mAh/g). Therefore, graphite is used as the negative electrode material. The energy density of lithium batteries is limited and cannot meet the high energy density requirements of power batteries. SiO material has a high capacity (2600mAh/g), the volume change during cycling is smaller than that of Si material, and the irreversible formation of lithium oxide and lithium silicate during the first charge and discharge process can play a buffer role in the cycle process, and the cycle performance is better than that of Si material. Si material is good, making it one of the alternatives for commercial graphite anodes. However, the SiO material will have a large volume expansion during the lithium intercalation process, which will destroy the conductive network. During the cycle process, the material is prone to pulverization, which will cause the battery capacity to decay rapidly; and the intrinsic conductivity of SiO is much lower than that of graphite. Severe electrode polarization occurs during discharge; during the charge-discharge process, the Coulombic efficiency decreases due to the continuous consumption of Li + due to the formation of the solid electrolyte interfacial film (SEI). Compared with graphite, SiO material as a negative electrode material is obviously lower, and the capacity increase of the cell is not obvious.
简单的将SiO材料和石墨两者混合在一起在制备极片过程中很难分散均匀，所以有效的将两者结合在一起形成复合材料能够有效的解决体积膨胀问题以及极片分布，有望成为下一代高能量密度电池负极材料的首选之一。例如，专利CN 109037636 A中提出了一种新方法，其内容为：1)按(1～5):10的质量比称取SiO和砂磨介质置于砂磨机罐体中，并加入助磨剂混合后进行砂磨将SiO纳米化，获得SiO悬浮液2)将SiO和无机碳源的悬浮液分散均匀后，进行喷雾干燥造粒，得到碳源包覆的SiO粉体；3)将所述碳源包覆的SiO粉体置于管式炉中在惰性气体的氛围下高温煅烧，再自然冷却至室温，得到SiO/碳复合材料；4)按10:100的质量比称取所述SiO/碳复合材料和石墨，并加入球磨介质进行球磨，将SiO/碳复合材料与石墨混合均匀后取出，制得SiO/碳/石墨复合负极材料。但是纳米化SiO制备过程复杂，成本高昂，不利于商业化，而且纳米化的SiO通过喷雾干燥又粘接在一起形成大颗粒，发挥不了纳米化的作用，膨胀过程中仍有巨大的应力。最后通过球磨的方法实现的石墨和SiO的复合材料，由于颗粒中间以物理方法聚合在一起，结合力不强，在循环过程中很容易分离开来而无法实现缓解体积膨胀的作用。据此需要一种理想的解决方案。Simply mixing the SiO material and graphite together is difficult to disperse uniformly in the process of preparing the pole piece, so effectively combining the two together to form a composite material can effectively solve the problem of volume expansion and pole piece distribution, and is expected to become the next One of the first choices of anode materials for a generation of high energy density batteries. For example, a new method is proposed in patent CN 109037636 A, the content of which is: 1) Weigh SiO and sanding medium in a mass ratio of (1～5):10 and place them in a sand mill tank, and add auxiliary After the abrasives are mixed, sanding is carried out to nanosize the SiO to obtain a SiO suspension 2) After the suspension of SiO and the inorganic carbon source is uniformly dispersed, spray-drying and granulation is performed to obtain the SiO powder coated with the carbon source; 3) The SiO powder is coated with the carbon source; The SiO powder coated with the carbon source is placed in a tube furnace and calcined at a high temperature in an atmosphere of an inert gas, and then naturally cooled to room temperature to obtain a SiO/carbon composite material; 4) Weigh the obtained SiO/carbon composite material in a mass ratio of 10:100. The SiO/carbon composite material and graphite are added, and a ball milling medium is added for ball milling, and the SiO/carbon composite material and graphite are mixed uniformly and taken out to obtain a SiO/carbon/graphite composite negative electrode material. However, the preparation process of nano-sized SiO is complicated and the cost is high, which is not conducive to commercialization, and the nano-sized SiO is bonded together to form large particles through spray drying, which cannot play the role of nano-sized, and there is still huge stress during the expansion process. Finally, the composite material of graphite and SiO realized by the ball milling method, because the particles are physically aggregated together, the bonding force is not strong, and it is easy to separate during the cycle process and cannot achieve the effect of relieving volume expansion. Accordingly, an ideal solution is required.
发明内容SUMMARY OF THE INVENTION
本发明为了克服SiO材料和石墨两者混合难分散均匀的问题，提供一种高首效SiO石墨复合负极材料的制备方法，将SiO镶嵌在石墨与石墨之间并通过碳源粘结在一起，通过外层的石墨有效的限制SiO的体积膨胀和粉化问题，通过Li盐大大提高负极材料的首次库伦效率和循环稳定性。同时该方法制备过程简单，成本低廉有利于量产化。In order to overcome the problem that the mixture of SiO material and graphite is difficult to disperse uniformly, the present invention provides a preparation method of a high first-efficiency SiO-graphite composite negative electrode material, wherein SiO is embedded between graphite and graphite and bonded together by a carbon source, The volume expansion and pulverization of SiO are effectively limited by the graphite in the outer layer, and the first Coulomb efficiency and cycle stability of the negative electrode material are greatly improved by the Li salt. At the same time, the preparation process of the method is simple, and the cost is low, which is beneficial to mass production.
为了实现上述目的，本发明采用以下技术方案：In order to achieve the above object, the present invention adopts the following technical solutions:
一种高首效SiO石墨复合负极材料的制备方法，包括如下步骤：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, comprising the following steps:
(1)将SiO、石墨、有机碳源、Li盐按照1:(1-10):(0.3-5):(0.01-1)的质量比混合均匀，得到混合物A，其中SiO的粒径小于石墨；(1) uniformly mix SiO, graphite, organic carbon source and Li salt according to the mass ratio of 1:(1-10):(0.3-5):(0.01-1) to obtain mixture A, wherein the particle size of SiO is less than graphite;
(2)将所述混合物A转移到造粒设备中在惰性气体氛围下进行造粒，得到SiO/石墨复合材料前驱体B；(2) transferring the mixture A to a granulation device and granulating under an inert gas atmosphere to obtain a SiO/graphite composite material precursor B;
(3)将所述复合材料前驱体B在惰性气体的氛围下高温煅烧，再自然冷却至室温，制得碳包覆的SiO/石墨复合负极材料。(3) calcining the composite material precursor B at a high temperature in an atmosphere of an inert gas, and then naturally cooling to room temperature to prepare a carbon-coated SiO/graphite composite negative electrode material.
本发明提供的SiO/碳/石墨复合材料的制备方法，首先将SiO与碳源、Li盐均匀混合并加热将碳源融化，使SiO颗粒和Li盐反应并均匀分散在碳源中；然后再与石墨复合进行高温碳化处理，使碳源重新融化将SiO颗粒粘结在石墨颗粒表面。SiO和石墨表面都被碳层所包覆，由于SiO的粒径小于石墨，造粒过程中SiO均匀地分散在石墨之间，形成石墨与石墨之间夹入SiO的结构，通过外层的石墨有效的限制SiO的体积膨胀和粉化问题。该方法制备工艺简单、成本低廉且重现性好，适用于大规模商业生产应用。In the preparation method of the SiO/carbon/graphite composite material provided by the present invention, firstly, SiO, carbon source and Li salt are uniformly mixed and heated to melt the carbon source, so that SiO particles and Li salt are reacted and uniformly dispersed in the carbon source; It is compounded with graphite for high-temperature carbonization, so that the carbon source is remelted and the SiO particles are bonded to the surface of the graphite particles. The surfaces of SiO and graphite are both covered by carbon layers. Since the particle size of SiO is smaller than that of graphite, SiO is uniformly dispersed between graphites during the granulation process, forming a structure in which SiO is sandwiched between graphite and graphite. Effectively limit the volume expansion and pulverization of SiO. The method has simple preparation process, low cost and good reproducibility, and is suitable for large-scale commercial production applications.
作为优选，步骤(1)中所述SiO的粒径为0.5-5μm。Preferably, the particle size of the SiO in step (1) is 0.5-5 μm.
作为优选，步骤(1)中所述有机碳源为葡萄糖、柠檬酸、沥青、聚乙烯吡咯烷酮、聚乙二醇、蔗糖、聚乙烯醇、聚丙烯酸、聚氯乙烯和酚醛树脂中的一种或几种。Preferably, the organic carbon source described in step (1) is one of glucose, citric acid, pitch, polyvinylpyrrolidone, polyethylene glycol, sucrose, polyvinyl alcohol, polyacrylic acid, polyvinyl chloride and phenolic resin or several.
作为优选，所述有机碳源为柠檬酸，且所述柠檬酸经过改性处理，具体操作为：Preferably, the organic carbon source is citric acid, and the citric acid is modified, and the specific operations are:
1)将柠檬酸分散于去离子水中，搅拌下加入二氧化钛使体系中二氧化钛浓度为180-300g/L，柠檬酸质量为二氧化钛的0.05-0.1％，湿法球磨20-30min，烘干得二氧化钛接枝的柠檬酸；1) Disperse citric acid in deionized water, add titanium dioxide under stirring so that the concentration of titanium dioxide in the system is 180-300g/L, the mass of citric acid is 0.05-0.1% of the titanium dioxide, wet ball milling for 20-30min, and dry to obtain a titanium dioxide connection. citric acid of branch;
2)将二氧化钛接枝的柠檬酸和聚氧化乙烯分别溶于二甲亚砜制得溶液，按柠檬酸和聚氧化乙烯的摩尔比(3-7):10将二氧化钛接枝的柠檬酸溶液滴加至聚氧化乙烯溶液中，在60-100℃下加热搅拌反应3-5h，反应液冷却后滴加至NaOH的乙醇溶液中，析出固体，固体洗涤、干燥后得到改性柠檬酸。2) citric acid and polyethylene oxide grafted by titanium dioxide are respectively dissolved in dimethyl sulfoxide to obtain a solution, and the citric acid solution grafted by titanium dioxide is dropped by the mol ratio (3-7) of citric acid and polyethylene oxide: 10 Add it to the polyethylene oxide solution, heat and stir at 60-100 ° C for 3-5 hours, the reaction solution is cooled and added dropwise to the ethanol solution of NaOH to precipitate a solid, and the solid is washed and dried to obtain modified citric acid.
有机碳源将SiO粘结固定在石墨夹层中，本发明对有机碳源柠檬酸做了改性处理：柠檬酸含有羟基和多个羧基，柠檬酸的羧基和二氧化钛表面的羟基进行反应，给柠檬酸接枝上 二氧化钛，二氧化钛表面的大量羟基有利于与SiO、石墨之间产生氢键，从而提高有机碳源的粘结性能，有效抑制SiO的粉碎。而接枝的二氧化钛相对于直接添加复合的二氧化钛颗粒，具有更好的分散性和稳定性。再将柠檬酸和聚氧化乙烯反应，生成交联网络结构，可以形成保护层，使SiO与电解液分离。而且柠檬酸和聚氧化乙烯反应后可以提高聚氧化乙烯的力学性能，柠檬酸起支撑作用，可以抑制SiO的体积膨胀。The organic carbon source bonds and fixes SiO in the graphite interlayer, and the present invention modifies the organic carbon source citric acid: citric acid contains hydroxyl groups and multiple carboxyl groups, and the carboxyl groups of citric acid react with the hydroxyl groups on the surface of titanium dioxide to give lemons Titanium dioxide is grafted with acid, and a large number of hydroxyl groups on the surface of titanium dioxide are conducive to the generation of hydrogen bonds with SiO and graphite, thereby improving the bonding performance of organic carbon sources and effectively inhibiting the pulverization of SiO. The grafted titanium dioxide has better dispersibility and stability than the directly added composite titanium dioxide particles. Then, citric acid and polyethylene oxide are reacted to form a cross-linked network structure, which can form a protective layer and separate SiO from the electrolyte. Moreover, the reaction of citric acid and polyethylene oxide can improve the mechanical properties of polyethylene oxide, and citric acid plays a supporting role, which can inhibit the volume expansion of SiO.
作为优选，步骤(1)中所述Li盐为LiH、LiOH和正丁基锂中的一种或者几种。Preferably, the Li salt in step (1) is one or more of LiH, LiOH and n-butyllithium.
作为优选，步骤(1)中所述石墨为人造石墨、天然石墨和膨胀石墨中的一种或几种。Preferably, the graphite in step (1) is one or more of artificial graphite, natural graphite and expanded graphite.
作为优选，步骤(2)中所述造粒设备为喷雾造粒机、VC包覆机、立式造粒釜或卧式造粒釜。Preferably, the granulation equipment described in step (2) is a spray granulator, a VC coating machine, a vertical granulation kettle or a horizontal granulation kettle.
作为优选，步骤(2)中所述造粒的过程为：先以3-10℃/min的速率升温至200-500℃保温30-60min，然后以3-10℃/min的速率升温至600-800℃保温1-3h。Preferably, the granulation process described in step (2) is as follows: first, the temperature is raised to 200-500°C at a rate of 3-10°C/min for 30-60min, and then heated to 600°C at a rate of 3-10°C/min. -800℃ for 1-3h.
作为优选，步骤(3)中所述高温煅烧的过程为：以3-10℃/min的速率升温至800-1100℃，保温1-3h。Preferably, the high-temperature calcination process in step (3) is as follows: the temperature is raised to 800-1100° C. at a rate of 3-10° C./min, and the temperature is kept for 1-3 hours.
作为优选，所述惰性气体为氦气、氩气及氮气中的一种或几种。Preferably, the inert gas is one or more of helium, argon and nitrogen.
因此，本发明具有如下有益效果：Therefore, the present invention has the following beneficial effects:
(1)本发明造粒过程中SiO均匀地分散在石墨之间，形成石墨与石墨之间夹入SiO的结构，通过外层的石墨有效的限制SiO的体积膨胀和粉化问题；(1) in the granulation process of the present invention, SiO is uniformly dispersed between graphites, forming a structure in which SiO is sandwiched between graphite and graphite, and effectively limiting the volume expansion and pulverization of SiO through the graphite of the outer layer;
(2)本发明对有机碳源柠檬酸做改性，进一步限制SiO的体积膨胀和粉化问题；(2) the present invention modifies the organic carbon source citric acid to further limit the volume expansion and pulverization problems of SiO;
(3)本发明负极材料中Li盐的加入大大提高了负极材料的首次库伦效率和循环稳定性；(3) The addition of Li salt in the negative electrode material of the present invention greatly improves the first Coulomb efficiency and cycle stability of the negative electrode material;
(4)本发明方法制备工艺简单、成本低廉且重现性好，适用于大规模商业生产应用。(4) The method of the present invention is simple in preparation process, low in cost and good in reproducibility, and is suitable for large-scale commercial production applications.
具体实施方式Detailed ways
下面通过具体实施例，对本发明的技术方案做进一步说明。The technical solutions of the present invention will be further described below through specific embodiments.
本发明中，若非特指，所采用的原料和设备等均可从市场购得或是本领域常用的，实施例中的方法，如无特别说明，均为本领域的常规方法。In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art, and the methods in the examples, unless otherwise specified, are all conventional methods in the art.
实施例1Example 1
一种高首效SiO石墨复合负极材料的制备方法，包括如下步骤：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, comprising the following steps:
(1)按照1:7:0.5:0.2的质量比分别取SiO、人造石墨、沥青、LiH，通过抽真空管道吸入VC混合机，快速搅拌30分钟，保证四种料进行有效的混合后停机；其中SiO的粒径为0.5μm，人造石墨的粒径为8μm；(1) According to the mass ratio of 1:7:0.5:0.2, take SiO, artificial graphite, pitch, and LiH respectively, inhale the VC mixer through the vacuum pipe, and stir quickly for 30 minutes to ensure that the four materials are effectively mixed and then shut down; The particle size of SiO is 0.5 μm, and the particle size of artificial graphite is 8 μm;
(2)将混合好后的材料通过真空设备转移到立式造粒釜中通入氦气，搅拌速度100转/分钟， 以3℃/min的升温速率升到300℃保温1小时，然后以5℃/min的升温速率升到700℃保温2小时，自然冷却降温后得到碳源包覆并粘结的石墨/SiO复合材料B；(2) The mixed material is transferred to the vertical granulation kettle by vacuum equipment and fed with helium, the stirring speed is 100 rev/min, and the temperature is raised to 300°C for 1 hour at a heating rate of 3°C/min. The heating rate of 5°C/min was increased to 700°C for 2 hours, and after natural cooling, the graphite/SiO composite material B covered and bonded by carbon source was obtained;
(3)将复合材料B转移到箱式炉中以5℃/min的升温速率升温到900℃，保温2小时随后自然冷却降温，即得到SiO/石墨复合负极材料。(3) The composite material B was transferred to a box furnace and heated to 900°C at a heating rate of 5°C/min, maintained for 2 hours and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
实施例2Example 2
一种高首效SiO石墨复合负极材料的制备方法，包括如下步骤：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, comprising the following steps:
(1)按照1:7:0.5:0.1的质量比分别取SiO、人造石墨、沥青、LiH，通过抽真空管道吸入VC混合机，快速搅拌30分钟，保证四种料进行有效的混合后停机；其中SiO的粒径为3μm，人造石墨的粒径为10μm；(1) According to the mass ratio of 1:7:0.5:0.1, take SiO, artificial graphite, pitch, and LiH respectively, suck in the VC mixer through the vacuum pipe, and stir quickly for 30 minutes to ensure that the four materials are effectively mixed and then shut down; The particle size of SiO is 3 μm, and the particle size of artificial graphite is 10 μm;
(2)将混合好后的材料通过真空设备转移到立式造粒釜中通入氩气，搅拌速度100转/分钟，以3℃/min的升温速率升到300℃保温1小时，然后以5℃/min的升温速率升到700℃保温2小时，自然冷却降温后得到碳源包覆并粘结的石墨/SiO复合材料B；(2) The mixed material is transferred to the vertical granulation kettle through the vacuum equipment and fed with argon, the stirring speed is 100 rev/min, and the temperature rise rate of 3 ℃/min is raised to 300 ℃ for 1 hour, and then with The heating rate of 5°C/min was increased to 700°C for 2 hours, and after natural cooling, the graphite/SiO composite material B covered and bonded by carbon source was obtained;
(3)将复合材料B转移到箱式炉中以5℃/min的升温速率升温到1000℃，保温2小时随后自然冷却降温，即得到SiO/石墨复合负极材料。(3) The composite material B was transferred to a box furnace and heated to 1000°C at a heating rate of 5°C/min, maintained for 2 hours and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
实施例3Example 3
一种高首效SiO石墨复合负极材料的制备方法，包括如下步骤：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, comprising the following steps:
(1)按照1:6:0.7:0.3的质量比分别取SiO、天然石墨、酚醛树脂、正丁基锂，通过抽真空管道吸入VC混合机，快速搅拌30分钟，保证四种料进行有效的混合后停机；其中SiO的粒径为5μm，人造石墨的粒径为15μm；(1) According to the mass ratio of 1:6:0.7:0.3, take SiO, natural graphite, phenolic resin, n-butyllithium respectively, suck in the VC mixer through the vacuum pipe, and stir quickly for 30 minutes to ensure that the four materials are effectively Stop after mixing; the particle size of SiO is 5μm, and the particle size of artificial graphite is 15μm;
(2)将混合好后的材料通过真空设备转移到立式造粒釜中通入氮气，搅拌速度100转/分钟，以3℃/min的升温速率升到300℃保温1小时，然后以5℃/min的升温速率升到700℃保温2小时，自然冷却降温后得到碳源包覆并粘结的石墨/SiO复合材料B；(2) transfer the mixed material to the vertical granulation kettle by vacuum equipment and feed nitrogen, the stirring speed is 100 rev/min, rise to 300 ℃ with a heating rate of 3 ℃/min and keep warm for 1 hour, then use 5 The heating rate of ℃/min was increased to 700 ℃ and kept for 2 hours, and after natural cooling, a carbon source-coated and bonded graphite/SiO composite material B was obtained;
(3)将复合材料B转移到箱式炉中以5℃/min的升温速率升温到1000℃，保温2小时随后自然冷却降温，即得到SiO/石墨复合负极材料。(3) The composite material B was transferred to a box furnace and heated to 1000°C at a heating rate of 5°C/min, maintained for 2 hours and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
实施例4Example 4
一种高首效SiO石墨复合负极材料的制备方法，包括如下步骤：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, comprising the following steps:
(1)按照1:1:0.3:0.01的质量比分别取SiO、人造石墨、柠檬酸、LiH，通过抽真空管道吸入VC混合机，快速搅拌30分钟，保证四种料进行有效的混合后停机；其中SiO的粒径为0.5μm，人造石墨的粒径为8μm；(1) According to the mass ratio of 1:1:0.3:0.01, take SiO, artificial graphite, citric acid, and LiH respectively, suck in the VC mixer through the vacuum pipe, and stir quickly for 30 minutes to ensure that the four materials are effectively mixed and then shut down. ; The particle size of SiO is 0.5 μm, and the particle size of artificial graphite is 8 μm;
(2)将混合好后的材料通过真空设备转移到立式造粒釜中通入氦气，搅拌速度100转/分钟， 以10℃/min的升温速率升到500℃保温30min，然后以10℃/min的升温速率升到800℃保温1小时，自然冷却降温后得到碳源包覆并粘结的石墨/SiO复合材料B；(2) The mixed material is transferred to the vertical granulation kettle by vacuum equipment and fed with helium, the stirring speed is 100 rev/min, and the temperature is raised to 500 ℃ with a heating rate of 10 ℃/min for 30min, then 10 ℃/min. The heating rate of ℃/min was increased to 800 ℃ for 1 hour, and the graphite/SiO composite material B covered with carbon source and bonded was obtained after natural cooling and cooling;
(3)将复合材料B转移到箱式炉中以10℃/min的升温速率升温到1100℃，保温1小时随后自然冷却降温，即得到SiO/石墨复合负极材料。(3) The composite material B was transferred to a box furnace and heated to 1100°C at a heating rate of 10°C/min, kept for 1 hour and then cooled naturally to obtain a SiO/graphite composite negative electrode material.
实施例5Example 5
一种高首效SiO石墨复合负极材料的制备方法，与实施例4的区别在于柠檬酸经过改性处理，具体操作为：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, the difference from Example 4 is that citric acid is modified, and the specific operations are:
1)将柠檬酸分散于去离子水中，搅拌下加入二氧化钛使体系中二氧化钛质量浓度为180g/L，柠檬酸质量为二氧化钛的0.1％，湿法球磨20min，烘干得二氧化钛接枝的柠檬酸；1) Disperse citric acid in deionized water, add titanium dioxide under stirring to make the mass concentration of titanium dioxide in the system be 180 g/L, the mass of citric acid is 0.1% of the titanium dioxide, wet ball milling for 20min, and dry to obtain the citric acid grafted on titanium dioxide;
2)将二氧化钛接枝的柠檬酸和聚氧化乙烯分别溶于二甲亚砜制得溶液，按柠檬酸和聚氧化乙烯的摩尔比7:10将二氧化钛接枝的柠檬酸溶液滴加至聚氧化乙烯溶液中，在60℃下加热搅拌反应5h，反应液冷却后滴加至含10wt％NaOH的乙醇溶液中，析出固体，固体洗涤、干燥后得到改性柠檬酸。2) The citric acid and polyethylene oxide grafted by titanium dioxide are respectively dissolved in dimethyl sulfoxide to obtain a solution, and the citric acid solution grafted on titanium dioxide is added dropwise to the polyoxyethylene according to the molar ratio of citric acid and polyethylene oxide 7:10. In the ethylene solution, the reaction was heated and stirred at 60° C. for 5 h. After cooling, the reaction solution was added dropwise to an ethanol solution containing 10 wt% NaOH to precipitate a solid. The solid was washed and dried to obtain modified citric acid.
实施例6Example 6
一种高首效SiO石墨复合负极材料的制备方法，与实施例4的区别在于柠檬酸经过改性处理，具体操作为：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, the difference from Example 4 is that citric acid is modified, and the specific operations are:
1)将柠檬酸分散于去离子水中，搅拌下加入二氧化钛使体系中二氧化钛质量浓度为300g/L，柠檬酸质量为二氧化钛的0.05％，湿法球磨30min，烘干得二氧化钛接枝的柠檬酸；1) Disperse citric acid in deionized water, add titanium dioxide under stirring so that the mass concentration of titanium dioxide in the system is 300g/L, the mass of citric acid is 0.05% of the titanium dioxide, wet ball milling for 30min, and oven dry to obtain the citric acid grafted on titanium dioxide;
2)将二氧化钛接枝的柠檬酸和聚氧化乙烯分别溶于二甲亚砜制得溶液，按柠檬酸和聚氧化乙烯的摩尔比3:10将二氧化钛接枝的柠檬酸溶液滴加至聚氧化乙烯溶液中，在100℃下加热搅拌反应3h，反应液冷却后滴加至含5wt％NaOH的乙醇溶液中，析出固体，固体洗涤、干燥后得到改性柠檬酸。2) The citric acid and polyethylene oxide grafted on titanium dioxide are respectively dissolved in dimethyl sulfoxide to obtain a solution, and the citric acid solution grafted on titanium dioxide is added dropwise to the polyethylene oxide by the molar ratio of citric acid and polyethylene oxide 3:10. In the ethylene solution, the reaction was heated and stirred at 100° C. for 3 hours. After cooling, the reaction solution was added dropwise to an ethanol solution containing 5 wt% NaOH to precipitate a solid. The solid was washed and dried to obtain modified citric acid.
实施例7Example 7
一种高首效SiO石墨复合负极材料的制备方法，与实施例4的区别在于柠檬酸经过改性处理，具体操作为：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, the difference from Example 4 is that citric acid is modified, and the specific operations are:
1)将柠檬酸分散于去离子水中，搅拌下加入二氧化钛使体系中二氧化钛质量浓度为200g/L，柠檬酸质量为二氧化钛的0.08％，湿法球磨25min，烘干得二氧化钛接枝的柠檬酸；1) Disperse citric acid in deionized water, add titanium dioxide under stirring so that the mass concentration of titanium dioxide in the system is 200g/L, and the mass of citric acid is 0.08% of the titanium dioxide, wet ball milling for 25min, and oven dry to obtain the citric acid grafted on titanium dioxide;
2)将二氧化钛接枝的柠檬酸和聚氧化乙烯分别溶于二甲亚砜制得溶液，按柠檬酸和聚氧化乙烯的摩尔比5:10将二氧化钛接枝的柠檬酸溶液滴加至聚氧化乙烯溶液中，在70℃下加热搅拌反应4h，反应液冷却后滴加至含8wt％NaOH的乙醇溶液中，析出固体，固体洗涤、干燥 后得到改性柠檬酸。2) The citric acid and polyethylene oxide grafted by titanium dioxide are respectively dissolved in dimethyl sulfoxide to obtain a solution, and the citric acid solution grafted on titanium dioxide is added dropwise to the polyoxyethylene in a molar ratio of 5:10 of citric acid and polyethylene oxide. In the ethylene solution, the reaction was heated and stirred at 70° C. for 4 h. After cooling, the reaction solution was added dropwise to an ethanol solution containing 8 wt% NaOH, and a solid was precipitated. The solid was washed and dried to obtain modified citric acid.
对比例1Comparative Example 1
一种高首效SiO石墨复合负极材料的制备方法，包括如下步骤：A preparation method of a high first-efficiency SiO graphite composite negative electrode material, comprising the following steps:
(1)按照1:0.1的质量比分别取SiO、沥青，通过抽真空管道吸入VC混合机，快速搅拌30分钟，保证两种料进行有效的混合后停机；(1) Take SiO and asphalt respectively according to the mass ratio of 1:0.1, inhale the VC mixer through the vacuuming pipeline, and stir quickly for 30 minutes to ensure that the two materials are effectively mixed and then shut down;
(2)将混合好后的材料通过真空设备转移到立式造粒釜中通入惰性气氛，搅拌速度100转/分钟，以3℃/min的升温速率升到300℃保温1小时，然后以5℃/min的升温速率升到700℃保温2小时，自然冷却降温后得到碳源包覆并粘结的SiO材料C；(2) The mixed material is transferred to the vertical granulation kettle by vacuum equipment and passed into an inert atmosphere, the stirring speed is 100 rev/min, and the temperature rise rate of 3 ℃/min is raised to 300 ℃ and kept for 1 hour. The heating rate of 5°C/min was raised to 700°C for 2 hours, and after natural cooling, the SiO material C coated and bonded by the carbon source was obtained;
(3)按照1:0.1的质量比分别取石墨、沥青，通过抽真空管道吸入VC混合机，快速搅拌30分钟，保证两种料进行有效的混合后停机；(3) Take graphite and pitch respectively according to the mass ratio of 1:0.1, inhale the VC mixer through the vacuuming pipeline, and stir rapidly for 30 minutes to ensure that the two materials are effectively mixed and then shut down;
(4)将混合好后的材料通过真空设备转移到立式造粒釜中通入惰性气氛，搅拌速度100转/分钟，以3℃/min的升温速率升到300℃保温1小时，然后以5℃/min的升温速率升到700℃保温2小时，自然冷却降温后得到碳源包覆并粘结的石墨材料D；(4) the mixed material is transferred to the vertical granulation kettle by vacuum equipment and passed into an inert atmosphere, the stirring speed is 100 rev/min, and the temperature rise rate of 3 ℃/min is raised to 300 ℃ and kept for 1 hour, and then with The heating rate of 5°C/min was raised to 700°C for 2 hours, and after natural cooling, a carbon source-coated and bonded graphite material D was obtained;
(5)将材料C和D混合后转移到箱式炉中以5℃/min的升温速率升温到1000℃，保温2小时随后自然冷却降温，即得到SiO/碳/石墨复合负极材料。(5) After mixing materials C and D, they were transferred to a box furnace and heated to 1000°C at a heating rate of 5°C/min.
性能测试Performance Testing
对实施例1-5和对比例1制得的SiO/石墨复合负极材料进行极片的制备、扣式电池的组装及电化学性能测试。具体步骤为：将由实施例1-5和对比例1制得的SiO/石墨复合负极材料与导电碳黑、羧甲基纤维素钠(CMC)、丁苯橡胶(SBR)按质量90:5:2:3混合，加入去离子水作为溶剂进行搅拌；搅拌均匀后，使用涂布设备均匀涂布于铜箔集流体上，在90℃真空干燥箱中烘烤24h，然后通过对辊机压制均匀，最后用冲片机制成直径为14mm的圆形极片；再以金属锂片为对电极，隔膜为聚丙烯膜(Celgard 2300)，电解液为1mol/L六氟磷酸锂与等体积比的碳酸乙烯脂、二甲基碳酸脂的混合溶液，在充满高纯氮气的真空手套箱中组装成2025扣式电池，进行电化学性能测试，测试结果如下表所示。测试时以0.1C倍率(1C按500mAh/g计)进行充放电循环，电压范围为0～1.5V，循环次数为100次。将循环100周后的电池进行拆解测量极片的膨胀率。The SiO/graphite composite negative electrode materials prepared in Examples 1-5 and Comparative Example 1 were subjected to preparation of pole pieces, assembly of button batteries and tests of electrochemical performance. The concrete steps are as follows: the SiO/graphite composite negative electrode material prepared by Examples 1-5 and Comparative Example 1 is mixed with conductive carbon black, sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) by mass 90:5: Mix at 2:3, add deionized water as a solvent for stirring; after stirring evenly, use coating equipment to evenly coat on the copper foil current collector, bake in a vacuum drying oven at 90 °C for 24 hours, and then press evenly by a roller machine , and finally use a punching machine to form a circular pole piece with a diameter of 14mm; then use a metal lithium plate as the counter electrode, the diaphragm is a polypropylene film (Celgard 2300), and the electrolyte is 1mol/L lithium hexafluorophosphate and ethylene carbonate in an equal volume ratio The mixed solution of dimethyl carbonate and dimethyl carbonate was assembled into a 2025 button battery in a vacuum glove box filled with high-purity nitrogen, and the electrochemical performance was tested. The test results are shown in the following table. During the test, charge-discharge cycles were performed at a rate of 0.1C (1C was calculated as 500mAh/g), the voltage range was 0-1.5V, and the number of cycles was 100 times. The battery after 100 cycles was disassembled to measure the expansion rate of the pole piece.
Figure PCTCN2021105896-appb-000001
Figure PCTCN2021105896-appb-000001
由表1中数据可以看出，由实施例1-5制备得到的SiO/石墨复合负极材料均具有较高的首次库伦效率及良好的循环稳定性，而对比例1则循环衰减严重，证明了将SiO均匀地分散并夹入到石墨层中，有效的缓解了体积膨胀，避免了SiO的快速粉化，从而大大提高了循环稳定性，Li盐的引入也大大提高了首效。另外从材料循环过程中的膨胀率也能看出由于SiO嵌入于石墨中抑制了体积膨胀。实施例5和实施例4的区别在于对柠檬酸做了改性，从结果看，改性后各个性能均有所提升，说明改性后的柠檬酸对抑制SiO的体积膨胀和粉化有积极作用。It can be seen from the data in Table 1 that the SiO/graphite composite anode materials prepared by Examples 1-5 all have high first Coulomb efficiency and good cycle stability, while Comparative Example 1 has serious cycle attenuation, which proves that The SiO is uniformly dispersed and sandwiched into the graphite layer, which effectively relieves the volume expansion and avoids the rapid pulverization of SiO, thereby greatly improving the cycle stability. The introduction of Li salt also greatly improves the first effect. In addition, it can be seen from the expansion rate during the material cycle that the volume expansion is suppressed due to the intercalation of SiO in the graphite. The difference between Example 5 and Example 4 is that citric acid has been modified. From the results, all properties have been improved after modification, indicating that the modified citric acid has a positive effect on inhibiting the volume expansion and pulverization of SiO. effect.
以上所述，仅是本发明的较佳实施例而已，并非对本发明作任何形式上的限制，虽然本发明已以较佳实施例揭露如上，然而并非用以限定本发明，任何熟悉本专业的技术人员，在不脱离本发明技术方案范围内，当可利用上述揭示的技术内容作出些许更动或修饰为等同变化的等效实施例，但凡是未脱离本发明技术方案内容，依据本发明的技术实质对以上实施例所作的任何简单修改、等同变化与修饰，均仍属于本发明技术方案的范围内。The above are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. The technical personnel, within the scope of the technical solution of the present invention, can make some changes or modifications by using the technical content disclosed above to be equivalent embodiments of equivalent changes, provided that they do not depart from the technical solution content of the present invention, according to the technical solution of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (9)

  1. 一种高首效SiO石墨复合负极材料的制备方法，其特征在于，包括如下步骤：A method for preparing a high first-efficiency SiO graphite composite negative electrode material, characterized in that it comprises the following steps:
    (1)将SiO、石墨、有机碳源和Li盐按照1:(1-10):(0.3-5):(0.01-1)的质量比混合均匀，得到混合物A，其中SiO的粒径小于石墨；(1) uniformly mix SiO, graphite, organic carbon source and Li salt according to the mass ratio of 1:(1-10):(0.3-5):(0.01-1) to obtain mixture A, wherein the particle size of SiO is less than graphite;
    (2)将所述混合物A在惰性气体氛围中造粒，得到SiO/石墨复合材料前驱体B；(2) granulating the mixture A in an inert gas atmosphere to obtain a SiO/graphite composite material precursor B;
    (3)将所述复合材料前驱体B在惰性气体氛围下煅烧，冷却，制得碳包覆的SiO/石墨复合负极材料；(3) calcining the composite material precursor B under an inert gas atmosphere and cooling to obtain a carbon-coated SiO/graphite composite negative electrode material;
    其中，所述有机碳源为改性柠檬酸，制备方法包括以下步骤：Wherein, the organic carbon source is modified citric acid, and the preparation method comprises the following steps:
    1)将柠檬酸分散于去离子水中，搅拌下加入二氧化钛使体系中二氧化钛浓度为180-300g/L，柠檬酸质量为二氧化钛的0.05-0.1％，湿法球磨，烘干得二氧化钛接枝的柠檬酸；1) Disperse citric acid in deionized water, add titanium dioxide under stirring so that the concentration of titanium dioxide in the system is 180-300g/L, and the mass of citric acid is 0.05-0.1% of titanium dioxide, wet ball milling, and drying to obtain lemons grafted with titanium dioxide acid;
    2)将二氧化钛接枝的柠檬酸和聚氧化乙烯分别溶于二甲亚砜制得溶液，按柠檬酸和聚氧化乙烯的摩尔比(3-7):10将二氧化钛接枝的柠檬酸溶液滴加至聚氧化乙烯溶液中，在60-100℃下加热搅拌反应3-5h，反应液冷却后滴加至NaOH的乙醇溶液中，析出固体，固体洗涤、干燥后得到改性柠檬酸。2) citric acid and polyethylene oxide grafted by titanium dioxide are respectively dissolved in dimethyl sulfoxide to obtain a solution, and the citric acid solution grafted by titanium dioxide is dropped by the mol ratio (3-7) of citric acid and polyethylene oxide: 10 Add it to the polyethylene oxide solution, heat and stir at 60-100 ° C for 3-5 hours, the reaction solution is cooled and added dropwise to the ethanol solution of NaOH to precipitate a solid, and the solid is washed and dried to obtain modified citric acid.
  2. 根据权利要求1所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，步骤(1)中所述SiO的粒径为0.5-5μm。The method for preparing a high first-efficiency SiO graphite composite negative electrode material according to claim 1, wherein the particle size of the SiO in step (1) is 0.5-5 μm.
  3. 根据权利要求1所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，步骤(1)中所述Li盐为LiH、LiOH和正丁基锂中的一种或者几种。The method for preparing a high first-efficiency SiO graphite composite negative electrode material according to claim 1, wherein the Li salt in step (1) is one or more of LiH, LiOH and n-butyllithium.
  4. 根据权利要求1或3所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，步骤(1)中所述石墨为人造石墨、天然石墨和膨胀石墨中的一种或几种。The method for preparing a high first-efficiency SiO graphite composite negative electrode material according to claim 1 or 3, wherein the graphite described in step (1) is one or more of artificial graphite, natural graphite and expanded graphite kind.
  5. 根据权利要求1所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，步骤1)中所述湿法球磨的时间为20-30min。The method for preparing a high first-efficiency SiO graphite composite negative electrode material according to claim 1, wherein the wet ball milling time in step 1) is 20-30 min.
  6. 根据权利要求1所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，步骤(2)中所述造粒设备为喷雾造粒机、VC包覆机、立式造粒釜、卧式造粒釜中的一种。The preparation method of a high first-efficiency SiO graphite composite negative electrode material according to claim 1, wherein the granulation equipment described in step (2) is a spray granulator, a VC coating machine, a vertical granulator One of the kettle and horizontal granulation kettle.
  7. 根据权利要求1或6所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，步骤(2)中所述造粒的过程为：先以3-10℃/min的速率升温至200-500℃保温30-60min，然后以3-10℃/min的速率升温至600-800℃保温1-3h。The method for preparing a high first-efficiency SiO graphite composite negative electrode material according to claim 1 or 6, wherein the granulation process in step (2) is: firstly at a rate of 3-10°C/min The temperature is raised to 200-500°C for 30-60min, and then heated to 600-800°C at a rate of 3-10°C/min for 1-3h.
  8. 根据权利要求1所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，步骤(3)中所述煅烧的过程为：以3-10℃/min的速率升温至800-1100℃，保温1-3h。The method for preparing a high first-efficiency SiO-graphite composite negative electrode material according to claim 1, wherein the calcining process in step (3) is: heating up to 800-800°C at a rate of 3-10°C/min 1100℃, keep warm for 1-3h.
  9. 根据权利要求1所述的一种高首效SiO石墨复合负极材料的制备方法，其特征在于，所述惰性气体为氦气、氩气及氮气中的一种或几种。The method for preparing a high first-efficiency SiO-graphite composite negative electrode material according to claim 1, wherein the inert gas is one or more of helium, argon and nitrogen.
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