WO2021189317A1 - 负极材料、电化学装置以及电子装置 - Google Patents

负极材料、电化学装置以及电子装置 Download PDF

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WO2021189317A1
WO2021189317A1 PCT/CN2020/081183 CN2020081183W WO2021189317A1 WO 2021189317 A1 WO2021189317 A1 WO 2021189317A1 CN 2020081183 W CN2020081183 W CN 2020081183W WO 2021189317 A1 WO2021189317 A1 WO 2021189317A1
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negative electrode
electrode material
particles
composite particles
buffer phase
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PCT/CN2020/081183
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English (en)
French (fr)
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蒋晨曦
张亚菲
谢远森
余红明
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宁德新能源科技有限公司
东莞新能源科技有限公司
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Priority to PCT/CN2020/081183 priority Critical patent/WO2021189317A1/zh
Priority to CN202080007796.7A priority patent/CN113302765A/zh
Publication of WO2021189317A1 publication Critical patent/WO2021189317A1/zh
Priority to US17/951,375 priority patent/US20230043554A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • H01M10/058—Construction or manufacture
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • This application relates to the field of energy storage technology, and in particular to an anode material, an electrochemical device including the anode material, and an electronic device including the electrochemical device.
  • silicon-based materials have extremely high capacity and low lithium deintercalation potential, and are ideal anode materials for next-generation high-volume energy-density electrochemical devices.
  • the volumetric energy density of the electrochemical device (electrochemical device capacity ⁇ discharge platform)/(length ⁇ width ⁇ thickness). It can be seen that when the material system (the capacity of the electrochemical device is the same as the discharge platform) and the length and width of the electrochemical device are the same, the factor that affects the volumetric energy density of the electrochemical device is the thickness of the electrochemical device. The greater the thickness, The volumetric energy density of the electrochemical device is lower. However, with the charge-discharge cycle of the electrochemical device, the pole pieces will expand to a certain extent, which causes the thickness of the electrochemical device to increase.
  • the thickness of the electrochemical device increases by about 10% from the completion of the preparation of the electrochemical device (the volume separation is completed) to 500 cycles of charge and discharge. %, most of the increase in thickness is due to the expansion of the negative pole piece. Especially for lithium batteries with silicon-based materials as the negative electrode material, the negative pole piece will expand even more after 500 charge and discharge cycles.
  • the inventors of the present application have conducted in-depth studies and found that in the anode material with silicon material, the amorphous silicon particles are dispersed in the buffer phase to form silicon composite particles, and the dispersion of the amorphous silicon particles in the buffer phase is controlled.
  • the non-uniformity while obtaining higher energy density, can greatly improve the cyclic expansion anisotropy of silicon particles, which causes the composite particle cracking problem, thereby improving the cyclic expansion problem of the negative electrode material.
  • a negative electrode material includes silicon composite particles, the silicon composite particles include amorphous silicon particles and a buffer phase, and the amorphous silicon particles are dispersed in the buffer phase. Wherein, the non-uniformity of the amorphous silicon particles dispersed in the buffer phase is less than or equal to 30%.
  • the consistency of the silicon composite particles in the cyclic expansion process can be improved, the expansion stress of the silicon composite particles can be greatly dispersed, and the cyclic expansion of the silicon composite particles can be avoided.
  • the anisotropy caused by the cracking of the particles thereby reducing the expansion of the negative electrode material during the cycle, and reducing the increase in the thickness of the negative pole piece.
  • the non-uniformity of the amorphous silicon particles dispersed in the buffer phase is less than or equal to 15%.
  • the inventors of the present application have conducted a large number of experimental studies and verifications, and found that by controlling the non-uniformity of the amorphous silicon particles dispersed in the buffer phase to no more than 15%, the consistency of the silicon composite particles during the cyclic expansion process can be further improved. , To further reduce the expansion of the negative electrode material during the cycle.
  • the sphericity of the silicon composite particles is greater than or equal to 0.50.
  • the inventors of the present application found that the silicon composite particles in the negative electrode material have high sphericity, and the expansion of the silicon composite particles in all directions during the cyclic expansion process can be kept consistent, avoiding the rotation of the silicon composite particles. Or rearrangement, thereby further reducing the thickness expansion of the negative pole piece.
  • the specific surface area of the negative electrode material is less than or equal to 5 m 2 /g.
  • the specific surface area of the negative electrode material will affect its reaction area with the electrolyte, thereby affecting the by-products and cycle life, and the by-products will increase the thickness of the negative pole piece and reduce the electrochemical device.
  • the energy density By controlling the specific surface area of the negative electrode material in a certain range, it is beneficial to reduce the generation of side reactions, thereby further improving the energy density and cycle life.
  • the particle size of the negative electrode material satisfies D90-D10 ⁇ 15 ⁇ m.
  • the particle size distribution range of the negative electrode material is narrow.
  • the volume expansion of the silicon composite particles is basically the same, which will not cause the rearrangement of the silicon composite particles, and can further improve the cycle thickness expansion of the negative electrode.
  • the buffer phase includes at least one element of carbon, oxygen, silicon, iron, titanium, aluminum, or cadmium.
  • the buffer phase includes at least one of silicon monoxide or silicon dioxide.
  • the silicon composite particles further include a conductive agent, the conductive agent is dispersed in the buffer phase, and the conductive agent is used to improve the conductivity of the silicon composite particles.
  • the conductive agent is dispersed in the buffer phase, and the conductive agent is used to improve the conductivity of the silicon composite particles.
  • the application also provides an electrochemical device, which includes a negative pole piece, the negative pole piece includes a negative electrode active material layer, and the negative electrode active material layer includes the above-mentioned negative electrode material.
  • the electrochemical device has lower cycle expansion thickness, higher cycle performance and long service life.
  • the application also provides an electronic device, which includes an electrochemical device.
  • FIG. 1 is a schematic diagram of the structure of a negative electrode material provided by an embodiment of the application.
  • Figure 2 is a schematic diagram of the X-ray energy spectrum dispersion test performed on the silicon composite particles in the negative electrode material.
  • FIG. 3 is a schematic structural diagram of an electrochemical device provided by an embodiment of the application.
  • FIG. 4 is a schematic structural diagram of an electronic device provided by an embodiment of the application.
  • Anode material 100 Silicon composite particles 10 Amorphous silicon particles 12 Buffer phase 14 Conductive agent 16 Electrochemical device 200 Negative pole piece twenty two Positive pole piece twenty four Isolation film 26 Electrolyte 28 Electronic device 300
  • D10 represents the particle size of the silicon composite particles 10 in the volume-based particle size distribution, starting from the small particle size side, and reaching 10% of the cumulative volume
  • D50 represents the silicon composite particles 10 in the volume-based particle size distribution, starting from the smallest particle size From the side, the particle size reaches 50% of the cumulative volume
  • D90 indicates that the particle size of the silicon composite particles 10 reaches 90% of the cumulative volume from the small particle size side in the volume-based particle size distribution.
  • the negative electrode material 100 includes silicon composite particles 10.
  • the silicon composite particles 10 include amorphous silicon particles 12 and a buffer phase 14, and the amorphous silicon particles 12 are dispersed in the buffer phase 14. It is defined that the non-uniformity of the amorphous silicon particles 12 dispersed in the buffer phase 14 is N, and N is less than or equal to 30%.
  • the calculation method of non-uniformity N is: For any internal plane of the silicon composite particles 10, use Energy Dispersive X-ray Spectroscopy (EDS) to scan the silicon element, and use "Integral peak area/line "Sweep distance" means the content of amorphous silicon particles 12 in the line, and the line sweep distance is greater than D50/2.
  • EDS Energy Dispersive X-ray Spectroscopy
  • Sweep distance means the content of amorphous silicon particles 12 in the line, and the line sweep distance is greater than D50/2.
  • FIG. 2 to define the content of amorphous silicon particles 12 in any line scan L1 as X
  • the content of amorphous silicon particles 12 in any line scan L2 as Y
  • the amorphous silicon particles 12 are dispersed in the buffer phase 14
  • the calculation formula of non-uniformity N is:
  • N Max
  • the silicon composite particles 10 of the present application include amorphous silicon particles 12 and a buffer phase 14. Compared with crystalline silicon particles when lithium is inserted, the (110) crystal plane expands faster than crystal planes in other directions, which easily leads to negative electrode materials. 100 lithium intercalation expansion and cracking of the negative electrode material 100.
  • the amorphous silicon particles 12 used in this application can maintain the isotropic expansion of the negative electrode material 100, thereby avoiding the expansion and cracking of the negative electrode material 100 during lithium intercalation, and reducing the cyclic expansion thickness of the negative pole piece. .
  • the non-uniformity of the amorphous silicon particles 12 dispersed in the buffer phase 14 is low, which can further improve the uniformity of the expansion process of the amorphous silicon particles 12, and further avoid the anisotropy of the expansion of the amorphous silicon particles 12, which may lead to the negative electrode material 100. Cracking further reduces the cyclic expansion thickness of the negative pole piece.
  • the non-uniformity of the amorphous silicon particles 12 dispersed in the buffer phase 14 is less than or equal to 15%. Controlling the non-uniformity of the amorphous silicon particles 12 dispersed in the buffer phase 14 to be less than or equal to 15% can greatly improve the consistency of the cyclic expansion process of the amorphous silicon particles 12, further avoid the cracking of the negative electrode material 100, and further reduce the negative electrode. The thickness of the film cyclically expands.
  • the sphericity of the silicon composite particles 10 is greater than or equal to 0.50.
  • the sphericity is the ratio of the surface area of a sphere having the same volume as the silicon composite particle 10 to the surface area of the silicon composite particle 10, and the surface area does not include the surface area generated by the internal pores of the silicon composite particle 10.
  • the silicon composite particles 10 are granulated to form particles with a certain degree of sphericity. Due to the high sphericity of the silicon composite particles 10, that is, the silicon composite particles 10 are highly regular in shape and have similar expansions in all directions. Therefore, during the charging process, the silicon composite particles 10 expand uniformly, and the silicon composite particles 10 will not be rearranged or rotated due to inconsistent expansion; during the discharge process, there is no steric hindrance between the silicon composite particles 10, and the silicon composite particles 10 The particles 10 can be better restored to the position before charging, and the thickness expansion of the negative pole piece is small.
  • the specific surface area (Brunauer-Emmett-Teller, BET) of the negative electrode material 100 is less than or equal to 5 m 2 /g.
  • the specific surface area of the negative electrode material 100 will affect the contact area between the negative electrode material 100 and the electrolyte. A larger specific surface area improves the reaction activity of the negative electrode material 100, and also increases the probability of side reactions. The by-products produced by the side reactions will cause the negative electrode.
  • the thickness of the pole piece increases. Therefore, controlling the specific surface area of the negative electrode material 100 within 5 m 2 /g is beneficial to reduce the occurrence of side reactions.
  • the specific surface area of the negative electrode material 100 can be controlled by controlling the number of small particles in the negative electrode material 100.
  • the particle size of the negative electrode material 100 satisfies D90-D10 ⁇ 15 ⁇ m. Therefore, the particle size distribution range of the negative electrode material 100 is narrow.
  • the particle size distribution of the negative electrode material 100 is controlled within a certain range, so that the negative electrode material 100 can return to the initial position after discharge, and prevent the thickness of the negative electrode sheet from increasing.
  • the buffer phase 14 includes at least one element of carbon, oxygen, silicon, iron, titanium, aluminum, or cadmium, that is, the buffer phase 14 includes carbon, oxygen, silicon, iron, titanium, aluminum, and cadmium.
  • the buffer phase 14 plays a certain buffering role in the expansion process of the amorphous silicon particles 12, and further improves the expansion of the negative electrode material 100 during the cycle.
  • the silicon composite particles 10 further include a conductive agent 16, such as a carbon-containing conductive agent (conductive carbon black, carbon nanotube, graphene, etc.).
  • a conductive agent 16 such as a carbon-containing conductive agent (conductive carbon black, carbon nanotube, graphene, etc.).
  • the conductive agent 16 is dispersed in the buffer phase 14, and the conductive agent 16 is used to improve the conductivity of the silicon composite particles 10, thereby improving the electrical performance of the negative electrode material 100.
  • the present application also provides an electrochemical device 200, wherein the electrochemical device 200 of the present application includes all devices capable of electrochemical reactions.
  • the electrochemical device 200 includes all kinds of primary batteries, secondary batteries, fuel cells, and capacitors (for example, supercapacitors).
  • the electrochemical device 200 may be a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery.
  • an electrochemical device 200 taking a lithium ion secondary battery as an example, includes a negative pole piece 22, which includes a negative electrode active material layer (not shown in the figure),
  • the anode active material layer includes the anode material 100 described above.
  • the electrochemical device 200 further includes a positive pole piece 24, a separator 26 and an electrolyte 28.
  • the isolation film 26 is located between the negative pole piece 22 and the positive pole piece 24, and the electrolyte 28 infiltrates the negative pole piece 22, the isolation film 26 and the positive pole piece 24.
  • the negative pole piece 22 includes the negative electrode material 100.
  • the present application provides a synthetic preparation method of the negative electrode material 100, which includes: (1) pyrolyzing a silane precursor to prepare amorphous silicon particles 12; (2) mechanically dispersing the amorphous silicon particles 12 in pitch (3) calcining to form silicon composite particles 10; (4) spheroidizing and granulating the silicon composite particles 10; (5) screening the silicon composite particles 10 meeting the particle size requirements.
  • the conductive agent 16 may be added during the preparation process of the negative electrode material 100.
  • the conductive agent 16 can be dispersed in the buffer phase 14, and further can be evenly distributed in the buffer phase 14. It should be understood that the conductive agent 16 can be selected by a person skilled in the art according to needs, and is not limited by any conventional conductive material in the art.
  • the negative electrode material 100, the conductive material, the binder, and the solvent are mixed and coated on the negative electrode current collector in a certain ratio, and dried to form the negative electrode active material layer.
  • the negative electrode current collector may be, but is not limited to, copper foil or nickel foil. It should be understood that those skilled in the art can select conventional conductive materials, binders, and solvents in the art according to needs without limitation.
  • the positive electrode material, the conductive material, the binder, and the solvent are mixed and coated on the positive electrode current collector in a certain ratio, and the positive electrode active material layer is formed after drying.
  • the positive electrode current collector may be, but is not limited to, aluminum foil or nickel foil. It should be understood that those skilled in the art can select conventional conductive materials, binders, and solvents in the art according to needs without limitation.
  • the positive electrode piece 24 includes a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode material.
  • the positive electrode material may include lithium cobalt oxide, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium manganate, One or more of lithium iron manganese phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, lithium iron phosphate, lithium titanate, and lithium-rich manganese-based materials.
  • the isolation film 26 includes, but is not limited to, at least one selected from polyethylene, polypropylene, polyethylene terephthalate, polyimide, and aramid.
  • polyethylene includes at least one component selected from high-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene.
  • polyethylene and polypropylene they have a good effect on preventing short circuits, and can improve the stability of the battery through the shutdown effect.
  • the electrolyte 28 may be one or more of a gel electrolyte, a solid electrolyte, and a liquid electrolyte, and the electrolyte 28 includes a lithium salt and a non-aqueous solvent.
  • the lithium salt is selected from LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB(C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2.
  • LiPF 6 is selected for lithium salt because it can give high ionic conductivity and improve cycle characteristics.
  • the non-aqueous solvent may be a carbonate compound, a carboxylate compound, an ether compound, other organic solvents, or a combination thereof.
  • the aforementioned carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate compound, or a combination thereof.
  • Examples of the above-mentioned other organic solvents are dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, Formamide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and phosphate esters and combinations thereof.
  • the non-aqueous solvent is selected from ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, methyl acetate, ethyl propionate, The group consisting of fluoroethylene carbonate and its combination.
  • the preparation method of the positive pole piece 24, the separator 26, the electrolyte 28, and the electrochemical device 200 in the embodiment of the present application can be any suitable conventional method in the field according to specific needs without departing from the spirit of the present application. , And not limited by it.
  • the method of manufacturing the lithium ion battery includes: winding, folding or stacking the negative electrode piece 22, the separator 26, and the positive electrode piece 24 in the above-mentioned embodiment in order.
  • the battery cell is packed into, for example, an aluminum plastic film, and an electrolyte 28 is injected, and then vacuum packaging, standing, chemical forming, and shaping are performed to obtain a lithium ion battery.
  • the present application also provides an electronic device 300.
  • the electronic device 300 includes an electrochemical device 200.
  • the electronic device 300 may be a consumer electronic product (such as a mobile communication device, a tablet computer, a notebook computer, a wearable device, etc.), an electric tool, Man-machine, energy storage device, power plant, etc. Referring to FIG. 4, in one embodiment, the electronic device 300 is a mobile communication device.
  • the silane precursor is cracked to prepare amorphous silicon particles, and the amorphous silicon particles are dispersed in pitch and then calcined to form silicon composite particles.
  • the mechanical dispersion conditions by controlling the mechanical dispersion conditions, the uniformity of the dispersion of the amorphous silicon particles in the pitch can be adjusted; and the ratio of the amorphous silicon particles to the pitch can be controlled so that the gram capacity of the prepared negative electrode material is 800 mAh/g.
  • the ball milling process is carried out to granulate, the ball milling conditions are controlled, the sphericity of the silicon carbon composite particles is adjusted, and the anode material of the appropriate particle size is finally screened out, the fine powder is removed, and the anode material in the amorphous silicon particle dispersion buffer phase is finally obtained.
  • the buffer phase is a carbon material
  • the non-uniformity of the amorphous silicon particles in the buffer phase is 36.3%
  • the sphericity of the silicon composite particles is 0.32
  • the negative electrode material D90-D10 17.3 ⁇ m
  • the specific surface area of the negative electrode material is 2.6m 2 / g.
  • the negative electrode material Polyacrylic Acid (PAA), conductive carbon black and Sodium Carboxymethyl Cellulose (CMC) according to the mass ratio of 0.87:0.1:0.02:0.01 and mixed with an appropriate amount of solvent are made
  • PAA Polyacrylic Acid
  • CMC Sodium Carboxymethyl Cellulose
  • the negative electrode slurry is coated on a copper foil with a thickness of 10 ⁇ m and then cold pressed.
  • the final coating weight is 2.0 g/cm 2 and the cold pressed density is 1.2 g/cm 3 .
  • the lithium metal sheet is used as the counter electrode, and the negative pole piece and electrolyte are assembled to form a 2032 type (diameter 20mm, thickness 3.2mm, of which the size of the negative pole piece is 1.54cm 2 ) button cell.
  • the solvent in the electrolyte is Ethylene Carbonate (EC), Propylene Carbonate (PC), Ethyl Methyl Carbonate (EMC) and Fluoroethylene carbonate (FEC) It is prepared according to the mass ratio of 3:3:2:2, and the electrolyte is 1mol/L LiPF 6 .
  • the button cell is allowed to stand in an environment of 45° C. for 48 hours to allow the electrolyte to infiltrate the negative pole piece and the metal lithium sheet.
  • the first delithiation capacity is measured as A
  • the delithiation capacity is measured as B when the number of cycles is n
  • the capacity retention rate B/A*100%.
  • Expansion rate of negative pole piece after n cycles (density of negative pole piece during cold pressing/density of negative pole piece after n cycles-1)*100%.
  • Table 1 shows the physical parameters and performance test results of the negative electrode material 100 prepared in Comparative Examples 1-15 and Examples 1-9.
  • the expansion rate of the negative pole piece 22 can be further reduced and the capacity retention rate is further improved.
  • the sphericity of the silicon composite particles 10 is not less than 0.50, which can reduce the expansion rate of the negative pole piece 22 and improve the capacity retention; the D90-D10 of the negative electrode material 100 should be controlled within 15 ⁇ m, and the specific surface area should not exceed 5m 2 /g. It is beneficial to further reduce the expansion rate of the negative pole piece 22 and improve the capacity retention rate.
  • the anode material 100 provided in the present application includes silicon composite particles 10, the silicon composite particles 10 include amorphous silicon particles 12 and a buffer phase 14, wherein the amorphous silicon particles 12 ensure that the electrochemical device 200 has a higher volumetric energy density.
  • the isotropy of the negative electrode material 100 during expansion can be ensured to prevent the negative electrode material 100 from cracking and increase the thickness of the negative electrode piece 22; the buffer phase 14 plays a certain buffer role in the expansion process of the amorphous silicon particles 12.

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Abstract

一种负极材料，负极材料包含硅复合颗粒，该硅复合颗粒包含非晶硅颗粒和缓冲相，非晶硅颗粒分散在缓冲相中。其中，非晶硅颗粒分散在缓冲相中的非均匀度小于或等于30％。本申请还提供包括上述负极材料的电化学装置以及包括该电化学装置的电子装置。本申请通过控制硅复合颗粒中非晶硅颗粒在缓冲相中分散的非均匀度，来避免硅复合颗粒膨胀的各向异性导致的颗粒开裂，提高负极材料的体积能量密度的同时，改善硅负极材料膨胀问题，进而改善电化学装置的循环性能和使用寿命。

Description

负极材料、电化学装置以及电子装置 技术领域
本申请涉及储能技术领域，尤其涉及一种负极材料、包括所述负极材料的电化学装置以及包括所述电化学装置的电子装置。
背景技术
近年来，随着移动设备、电动汽车等产品的快速发展，使得高体积能量密度的电化学装置受到大量的关注和研究。其中，硅基材料具有极高的容量，较低的脱嵌锂电位，是下一代高体积能量密度电化学装置的理想负极材料。
其中，电化学装置的体积能量密度＝(电化学装置容量×放电平台)/(长×宽×厚)。可知，在材料体系(电化学装置容量和放电平台一致)和电化学装置的长度、宽度尺寸相同的情况下，影响电化学装置的体积能量密度的因素为电化学装置的厚度，厚度越大，电化学装置的体积能量密度越低。但是随着电化学装置的充放电循环，极片均会有一定程度的膨胀导致电化学装置的厚度增加。例如，以商业化的钴酸锂和石墨分别为正、负极材料的电化学装置为例，从电化学装置完成制备(分容完成)到充放电循环500次，电化学装置的厚度增加约10％，其中大部分厚度增加是由于负极极片膨胀导致的。尤其对于硅基材料作为负极材料的锂电池，充放电500次负极极片膨胀量会更大。
发明内容
有鉴于此，有必要提供一种在充放电过程中减小负极极片厚度 膨胀的硅负极材料，以解决上述问题。
本申请发明人等进行了深入研究，结果发现，在具有硅材料的负极材料中，通过将非晶硅颗粒分散在缓冲相中组成硅复合颗粒，并控制非晶硅颗粒在缓冲相中分散的非均匀度，在获得较高能量密度的同时，可以极大改善硅颗粒循环膨胀各项异性带来复合颗粒开裂问题，进而改善负极材料的循环膨胀问题。
即，为了解决上述问题，提供了以下的手段。
一种负极材料，包含硅复合颗粒，该硅复合颗粒包含非晶硅颗粒和缓冲相，非晶硅颗粒分散在缓冲相中。其中，非晶硅颗粒分散在缓冲相中的非均匀度小于或等于30％。
通过控制非晶硅颗粒分散在缓冲相中的非均匀度在一定范围内，可以提高硅复合颗粒在循环膨胀过程中的一致性，极大的分散硅复合颗粒膨胀应力，避免硅复合颗粒循环膨胀的各向异性导致的颗粒开裂，进而减小负极材料在循环过程中的膨胀，减小负极极片厚度增加。
在本申请一些实施例中，非晶硅颗粒分散在缓冲相中的非均匀度小于或等于15％。本申请发明人等通过大量试验研究及验证，结果发现，通过将非晶硅颗粒分散在缓冲相中的非均匀度控制在不超过15％，可以进一步提高硅复合颗粒循环膨胀过程中的一致性，进一步减小负极材料在循环过程中的膨胀。
在本申请一些实施例中，硅复合颗粒的球形度大于或等于0.50。本申请发明人等通过试验研究和验证，结果发现，负极材料中的硅复合颗粒球形度高，硅复合颗粒在循环膨胀过程中，向各方向的膨胀量可以保持一致，避免硅复合颗粒发生旋转或重排，从而进一步减小负极极片厚度膨胀。
在本申请一些实施例中，负极材料的比表面积小于或等于5m 2/g。本申请发明人等通过实验研究和验证，结果发现，负极材料的比表面积会影响其与电解质反应面积，从而影响副产物及循环寿命，且副产物会造成负极极片厚度增加，降低电化学装置的能量密度。通过控制负极材料的比表面积在一定范围，有利于减少副反应的产生，进而进一步提高能量密度和循环寿命。
在本申请一些实施例中，负极材料的粒度满足D90-D10≤15μm。负极材料的粒度分布范围较窄，硅复合颗粒在膨胀过程中，硅复合颗粒的体积膨胀量基本相同，不会导致硅复合颗粒重排，可以进一步改善负极极片循环厚度膨胀问题。
在本申请一些实施例中，缓冲相包括碳、氧、硅、铁、钛、铝或者镉中的至少一种元素。
在本申请一些实施例中，缓冲相包括一氧化硅或者二氧化硅中的至少一种。
在本申请一些实施例中，硅复合颗粒还包含导电剂，导电剂分散在缓冲相中，导电剂用于提高硅复合颗粒的导电性。通过将导电剂分散在硅复合颗粒中，可以提高硅复合颗粒内部的导电性能，进而提高负极材料的电性能。
本申请还提供一种电化学装置，该电化学装置包括负极极片，负极极片包括负极活性材料层，负极活性材料层包括上述负极材料。该电化学装置具有较低的循环膨胀厚度、较高的循环性能和长使用寿命。本申请还提供一种电子装置，电子装置包括电化学装置。
附图说明
图1为本申请一实施例提供的负极材料的结构示意图。
图2为对负极材料中的硅复合颗粒进行X射线能谱色散测试示 意图。
图3为本申请一实施例提供的电化学装置的结构示意图。
图4为本申请一实施例提供的电子装置的结构示意图。
主要元件符号说明
负极材料 100
硅复合颗粒 10
非晶硅颗粒 12
缓冲相 14
导电剂 16
电化学装置 200
负极极片 22
正极极片 24
隔离膜 26
电解质 28
电子装置 300
如下具体实施方式将结合上述附图进一步说明本申请。
具体实施方式
为了能够更清楚地理解本申请的上述目的、特征和优点，下面结合附图和具体实施方式对本申请进行详细描述。需要说明的是，在不冲突的情况下，本申请的实施方式及实施方式中的特征可以相互组合。在下面的描述中阐述了很多具体细节以便于充分理解本申请，所描述的实施方式仅仅是本申请一部分实施方式，而不是全部的实施方式。基于本申请中的实施方式，本领域普通技术人员在没 有做出创造性劳动前提下所获得的所有其他实施方式，都属于本申请保护的范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。本文中在本申请的说明书中所使用的术语只是为了描述具体的实施方式的目的，不是旨在于限制本申请。本文所使用的术语“和/或”包括一个或多个相关的所列项目的所有的和任意的组合。
在本文中，D10表示硅复合颗粒10在体积基准的粒度分布中，从小粒径侧起、达到体积累积10％的粒径；D50表示硅复合颗粒10在体积基准的粒度分布中，从小粒径侧起、达到体积累积50％的粒径；D90表示硅复合颗粒10在体积基准的粒度分布中，从小粒径侧起、达到体积累积90％的粒径。
请参阅图1，本申请提供一种负极材料100，负极材料100包含硅复合颗粒10，硅复合颗粒10包含非晶硅颗粒12和缓冲相14，非晶硅颗粒12分散在缓冲相14中。定义非晶硅颗粒12分散在缓冲相14中的非均匀度为N，N小于或等于30％。
其中，非均匀度为N的计算方法为：对于硅复合颗粒10的任意内部平面采用能量色散X射线光谱仪(Energy Dispersive X-ray Spectroscopy，EDS)进行硅元素线扫，用“积分峰面积/线扫距离”表示该条线的非晶硅颗粒12的含量，线扫距离大于D50/2。请参阅图2，定义任意一条线扫L1的非晶硅颗粒12的含量为X，另外任意一条线扫L2的非晶硅颗粒12的含量为Y，非晶硅颗粒12分散在缓冲相14中的非均匀度N的计算公式为：
N＝Max|X-Y|/(X+Y)。
本申请的硅复合颗粒10包含非晶硅颗粒12和缓冲相14，相较于结晶硅颗粒在嵌锂时，(110)晶面相较于其他方向的晶面膨胀速 度更快，容易导致负极材料100嵌锂膨胀以及负极材料100开裂，本申请采用非晶硅颗粒12能够保持负极材料100膨胀的各向同性，从而避免负极材料100在嵌锂时膨胀以及开裂，减小负极极片循环膨胀厚度。
而且，非晶硅颗粒12分散在缓冲相14中非均匀度较低，能进一步改善非晶硅颗粒12膨胀过程的一致性，进一步避免非晶硅颗粒12膨胀的各向异性而导致负极材料100开裂，进一步减小负极极片循环膨胀厚度。
可选的，非晶硅颗粒12分散在缓冲相14中的非均匀度小于或等于15％。控制非晶硅颗粒12分散在缓冲相14中的非均匀度小于或等于15％，可以极大改善非晶硅颗粒12循环膨胀过程的一致性，进一步避免负极材料100开裂，进一步减小负极极片循环膨胀厚度。
进一步地，硅复合颗粒10的球形度大于或等于0.50。其中，球形度为与硅复合颗粒10相同体积的球体的表面积和硅复合颗粒10的表面积的比，表面积不包括硅复合颗粒10内部孔隙产生的表面积。
传统的负极材料在多次充放电过程中膨胀，若颗粒的球形度低于0.50，即颗粒呈不规则形状，充电前颗粒呈堆积状态，在充电过程中，锂离子嵌入负极材料(即嵌锂过程)，颗粒发生膨胀。由于颗粒的形状不规整，在膨胀过程中向各方向的膨胀量不同，从而导致各颗粒之间相互挤压，部分颗粒旋转或重排。在放电过程中，锂离子脱出负极材料(即脱锂过程)，颗粒收缩，由于颗粒的形状不规整、存在棱角，颗粒之间具有空间位阻而无法恢复至充电之前的初始位置，孔隙率不断增加，负极材料100在负极极片上的堆积填充密度降低，导致负极极片厚度增加。
本申请通过对硅复合颗粒10进行造粒处理，形成具有一定球形度的颗粒，由于硅复合颗粒10的球形度高，即硅复合颗粒10形状高度规整，各方向的膨胀量相近。因此，在充电过程中，硅复合颗粒10均匀膨胀，而不会因膨胀量不一致而导致硅复合颗粒10重排或旋转；在放电过程中，硅复合颗粒10之间没有空间位阻，硅复合颗粒10可以较好地恢复至充电之前的位置，负极极片厚度膨胀较小。
在本申请一实施方式中，负极材料100的比表面积(布鲁诺-埃梅特-特勒，Brunauer-Emmett-Teller，BET)小于或等于5m 2/g。负极材料100的比表面积会影响负极材料100与电解质的接触面积，较大的比表面积提高负极材料100反应活性的同时，也增加了副反应发生的几率，发生副反应产生的副产物会造成负极极片厚度的增加。因此将负极材料100的比表面积控制在5m 2/g以内有利于减少副反应的产生。其中，在本实施方式中，可以通过控制负极材料100中小颗粒的数量来控制负极材料100的比表面积。
在本申请一实施方式中，负极材料100的粒度满足D90-D10≤15μm。因此，负极材料100的粒度分布范围较窄。当粒度相差较大的颗粒堆积在一起，在充放电过程中，较大粒度的颗粒体积膨胀较大，较小粒度的颗粒体积膨胀较小，从而导致颗粒重排；且放电后，颗粒难以回到初始位置，从而导致负极极片厚度增加。本申请控制负极材料100的粒度分布在一定范围内，能够使得负极材料100在放电后回到初始位置，避免负极极片厚度增加。
在本实施方式中，缓冲相14包括碳、氧、硅、铁、钛、铝或者镉中的至少一种元素，即缓冲相14包括碳、氧、硅、铁、钛、铝以及镉等组成的单质、化合物或者混合物，例如碳材料、一氧化硅以 及二氧化硅等。缓冲相14在非晶硅颗粒12的膨胀过程中起到一定的缓冲作用，进一步改善负极材料100在循环过程中的膨胀。
在本申请一实施方式中，硅复合颗粒10还包含导电剂16，例如含碳导电剂(导电炭黑、碳纳米管以及石墨烯等)。导电剂16分散在缓冲相14中，导电剂16用于提高硅复合颗粒10的导电性，进而提高负极材料100的电性能。
本申请还提供一种电化学装置200，其中，本申请的电化学装置200包括所有能够发生电化学反应的装置。具体的，电化学装置200包括所有种类的原电池、二次电池、燃料电池和电容器(例如超级电容器)。可选地，电化学装置200可以为锂二次电池，包括锂金属二次电池、锂离子二次电池、锂聚合物二次电池和锂离子聚合物二次电池。
请参阅图3，在本申请一实施方式中，电化学装置200，以锂离子二次电池为例，包括负极极片22，负极极片22包括负极活性材料层(图中未示出)，负极活性材料层包括上述负极材料100。
在本申请一实施方式中，电化学装置200还包括正极极片24、隔离膜26以及电解质28。隔离膜26位于负极极片22以及正极极片24之间，电解质28浸润负极极片22、隔离膜26以及正极极片24。其中，负极极片22包含负极材料100。
在本申请一实施方式中，本申请提供负极材料100的合成制备方法，包括：(1)采用硅烷前驱体裂解制备非晶硅颗粒12；(2)将非晶硅颗粒12机械分散在沥青中；(3)煅烧形成硅复合颗粒10；(4)对硅复合颗粒10进行球形化造粒；(5)筛选符合粒度要求的硅复合颗粒10。在一些实施例中，负极材料100制备过程中还可以加入导电剂16。导电剂16可以分散在缓冲相14中，进一步的可以在缓冲相14中均匀分布。应理解，导电剂16可以由本领域技术人 员根据需要选择本领域常规的导电物质，而不受其限制。
在本申请一实施方式中，负极材料100、导电物质、粘结剂以及溶剂按照一定的比例混合涂覆于负极集流体上，干燥后形成负极活性材料层。在一些实施例中，负极集流体可为，但不限于，铜箔或镍箔。应理解，本领域技术人员可以根据需要选择本领域常规的导电物质、粘结剂以及溶剂，而不受其限制。
在本申请一实施方式中，正极材料、导电物质、粘结剂以及溶剂按照一定的比例混合涂覆于正极集流体上，干燥后形成正极活性材料层。在一些实施例中，正极集流体可为，但不限于，铝箔或镍箔。应理解，本领域技术人员可以根据需要选择本领域常规的导电物质、粘结剂以及溶剂，而不受其限制。
在本申请一实施方式中，正极极片24包含正极活性材料层，正极活性材料层包括正极材料，正极材料可以包括钴酸锂、镍钴锰酸锂、镍钴铝酸锂、锰酸锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、磷酸铁锂、钛酸锂和富锂锰基材料中的一种或多种。
在本申请一实施方式中，隔离膜26包括，但不限于，选自聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯、聚酰亚胺和芳纶中的至少一种。举例来说，聚乙烯包括选自高密度聚乙烯、低密度聚乙烯和超高分子量聚乙烯中的至少一种组分。尤其是聚乙烯和聚丙烯，它们对防止短路具有良好的作用，并可以通过关断效应改善电池的稳定性。
在本申请一实施方式中，电解质28可以是凝胶电解质、固态电解质和液态电解质中的一种或多种，电解质28包括锂盐和非水溶剂。
在本申请一实施方式中，锂盐选自LiPF 6、LiBF 4、LiAsF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、 LiC(SO 2CF 3) 3、LiSiF 6、LiBOB和二氟硼酸锂中的一种或多种。举例来说，锂盐选用LiPF 6，因为它可以给出高的离子导电率并改善循环特性。
非水溶剂可为碳酸酯化合物、羧酸酯化合物、醚化合物、其它有机溶剂或它们的组合。
上述碳酸酯化合物可为链状碳酸酯化合物、环状碳酸酯化合物、氟代碳酸酯化合物或其组合。
上述其它有机溶剂的实例为二甲亚砜、1,2-二氧戊环、环丁砜、甲基环丁砜、1,3-二甲基-2-咪唑烷酮、N-甲基-2-吡咯烷酮、甲酰胺、二甲基甲酰胺、乙腈、磷酸三甲酯、磷酸三乙酯、磷酸三辛酯、和磷酸酯及其组合。
在本申请一实施方式中，非水溶剂选自由碳酸乙烯酯、碳酸丙烯酯、碳酸二乙酯、碳酸二甲酯、碳酸甲乙酯、碳酸亚丙酯、醋酸甲酯、丙酸乙酯、氟代碳酸乙烯酯及其组合所组成的群组。
应理解，本申请实施例中的正极极片24、隔离膜26、电解质28以及电化学装置200的制备方法，在不违背本申请的精神下，可以根据具体需要选择本领域任何合适的常规方法，而不受其限制。在制造电化学装置200的方法的一个实施方案中，锂离子电池的制备方法包括：将上述实施例中的负极极片22、隔离膜26及正极极片24按顺序卷绕、折叠或堆叠成电芯，将电芯装入例如铝塑膜中，并注入电解质28，随后进行真空封装、静置、化成、整形等工序，以获得锂离子电池。
本申请还提供一种电子装置300，电子装置300包括电化学装置200，电子装置300可以是消费性电子产品(如移动通信装置、平板电脑、笔记本电脑、可穿戴设备等)、电动工具、无人机、储能装置、动力装置等。请参阅图4，在一实施方式中，电子装置300 为移动通信装置。
以下通过具体实施例来对本申请进行说明。
对比例1
采用硅烷前驱体裂解制备成非晶硅颗粒，将非晶硅颗粒分散于沥青中后煅烧，形成硅复合颗粒。其中，通过可控制机械分散条件，调节非晶硅颗粒在沥青中的分散均匀度；控制非晶硅颗粒与沥青的比例，使得制备的负极材料的克容量为800mAh/g。然后经过球磨处理进行造粒，控制球磨条件，调节硅碳复合颗粒球形度，最后筛选出合适粒度的负极材料，去除细粉，最终得到非晶硅颗粒分散缓冲相中的负极材料。其中，缓冲相为碳材料，非晶硅颗粒在缓冲相中的非均匀度为36.3％，硅复合颗粒球形度为0.32，负极材料D90-D10＝17.3μm，负极材料比表面积为2.6m 2/g。
将负极材料、聚丙烯酸(Polyacrylic Acid，PAA)、导电炭黑以及羧甲基纤维素钠(Sodium Carboxymethyl Cellulose，CMC)按照质量比为0.87:0.1:0.02:0.01的比例并与适量溶剂混合制成负极浆料，将负极浆料涂覆于厚度为10μm的铜箔上后进行冷压，最终涂布重量为2.0g/cm 2，冷压密度为1.2g/cm 3。以金属锂片为对电极，与负极极片以及电解质组装成2032型(直径20mm，厚度3.2mm，其中负极极片尺寸为1.54cm 2)扣式电池。其中，电解质中的溶剂为碳酸丙烯酯(Ethylene Carbonate，EC)、碳酸丙烯酯(Propylene Carbonate，PC)、碳酸甲乙酯(Ethyl Methyl Carbonate，EMC)以及氟代碳酸乙烯酯(Fluoroethylene carbonate，FEC)按照质量比为3:3:2:2进行配制，电解质为1mol/L的LiPF 6。扣式电池组装完成后，将扣式电池在45℃的环境中静置48h，以使电解质浸润负极极片以及金属锂片。然后进行充放电，充放电的流程为：1mA的电流放电至5mV，0.1mA的电流放电至5mV，然后以1mA的电流充电至1.5V， 如此循环100次。然后测试负极极片密度、容量保持率和负极极片膨胀率。
负极极片密度
称重测得负极极片涂布重量Wg/cm 2，使用万分尺测量负极极片(包含负极集流体)厚度T1μm，负极集流体厚度T2μm，则负极极片密度＝1000*W/(T1-T2)。
容量保持率
在上述充放电流程情况下，测得第一次脱锂容量为A，循环次数为n时测得脱锂容量为B，则容量保持率＝B/A*100％。
负极极片膨胀率
循环n次后负极极片膨胀率＝(冷压时负极极片密度/循环n次后负极极片密度-1)*100％。
对比例2
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为35.2％，硅复合颗粒的球形度为0.30，负极材料D90-D10＝12.2μm，负极材料比表面积为2.7m 2/g。
对比例3
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为35.9％，硅复合颗粒的球形度为0.35，负极材料D90-D10＝8.7μm，负极材料比表面积为2.6m 2/g。
对比例4
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为36.8％，硅复合颗粒的球形度为0.66，负极材料D90-D10＝16.9μm，负极材料比表面积为2.5m 2/g。
对比例5
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为 34.6％，硅复合颗粒的球形度为0.62，负极材料D90-D10＝12.7μm，负极材料比表面积为2.6m 2/g。
对比例6
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为35.4％，硅复合颗粒的球形度为0.63，负极材料D90-D10＝8.4μm，负极材料比表面积为2.7m 2/g。
对比例7
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为34.4％，硅复合颗粒的球形度为0.88，负极材料D90-D10＝18.0μm，负极材料比表面积为2.5m 2/g。
对比例8
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为35.8％，硅复合颗粒的球形度为0.86，负极材料D90-D10＝12.0μm，负极材料比表面积为2.6m 2/g。
对比例9
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为35.7％，硅复合颗粒的球形度为0.84，负极材料D90-D10＝8.3μm，负极材料比表面积为2.6m 2/g。
对比例10
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为24.2％，硅复合颗粒的球形度为0.35，负极材料D90-D10＝16.8μm，负极材料比表面积为2.5m 2/g。
对比例11
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为25.1％，硅复合颗粒的球形度为0.31，负极材料D90-D10＝12.8μm，负极材料比表面积为2.5m 2/g。
对比例12
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为23.3％，硅复合颗粒的球形度为0.33，负极材料D90-D10＝8.6μm，负极材料比表面积为2.5m 2/g。
对比例13
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为9.9％，硅复合颗粒的球形度为0.65，负极材料D90-D10＝17.3μm，负极材料比表面积为2.6m 2/g。
对比例14
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为10.3％，硅复合颗粒的球形度为0.89，负极材料D90-D10＝17.7μm，负极材料比表面积为2.5m 2/g。
对比例15
与对比例1不同的是：非晶硅颗粒在缓冲相中的非均匀度为10.3％，硅复合颗粒的球形度为0.83，负极材料D90-D10＝7.9μm，负极材料比表面积为8.3m 2/g。
实施例1
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为25.9％，硅复合颗粒10的球形度为0.66，负极材料D90-D10＝12.3μm，负极材料比表面积为2.5m 2/g。
实施例2
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为24.3％，硅复合颗粒10的球形度为0.85，负极材料D90-D10＝8.5μm，负极材料比表面积为2.4m 2/g。
实施例3
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀 度为26.1％，硅复合颗粒10的球形度为0.85，负极材料D90-D10＝12.3μm，负极材料比表面积为2.6m 2/g。
实施例4
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为27.4％，硅复合颗粒10的球形度为0.88，负极材料D90-D10＝8.2μm，负极材料比表面积为2.5m 2/g。
实施例5
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为10.4％，硅复合颗粒10的球形度为0.68，负极材料D90-D10＝12.9μm，负极材料比表面积为2.7m 2/g。
实施例6
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为10.8％，硅复合颗粒10的球形度为0.62，负极材料D90-D10＝8.4μm，负极材料比表面积为2.8m 2/g。
实施例7
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为12.4％，硅复合颗粒10的球形度为0.84，负极材料D90-D10＝12.0μm，负极材料比表面积为2.6m 2/g。
实施例8
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为11.4％，硅复合颗粒10的球形度为0.89，负极材料D90-D10＝8.5μm，负极材料比表面积为2.6m 2/g。
实施例9
与对比例1不同的是：非晶硅颗粒12在缓冲相14中的非均匀度为12.4％，硅复合颗粒10的球形度为0.82，负极材料D90-D10＝8.4μm，负极材料比表面积为4.3m 2/g。
请参阅表1，表1为对比例1-15以及实施例1-9制备的负极材料100的物理参数以及性能测试结果。
表1
Figure PCTCN2020081183-appb-000001
从表1的测试结果可以看出，非晶硅颗粒12分散在缓冲相14中的非均匀度不超过30％时，负极极片22膨胀率可以减小到比较理想的程度，并获得较好的容量保持率。即通过硅颗粒非晶化，提高非晶硅颗粒在复合颗粒中分散的均匀性，有利于提高硅复合颗粒的膨胀各方向均匀性，减小负极膨胀厚度，提高电化学装置的循环性能和使用寿命。
进一步的，非晶硅颗粒12分散在缓冲相14中的非均匀度不超过15％时，负极极片22膨胀率可以进一步较大的减小，容量保持率进一步提升。
硅复合颗粒10球形度不小于0.50，可以减小负极极片22膨胀率，提高容量保持率；负极材料100的D90-D10控制在不超过15μm，比表面积控制在不超过5m 2/g，均有利于进一步减小负极极片22膨胀率，提高容量保持率。
本申请提供的负极材料100，包含硅复合颗粒10，硅复合颗粒10包含非晶硅颗粒12和缓冲相14，其中，非晶硅颗粒12在保证具有电化学装置200具有较高体积能量密度的同时，还能保证负极材料100膨胀时的各向同性，避免负极材料100开裂而导致负极极片22厚度增加；缓冲相14在非晶硅颗粒12的膨胀过程中起到一定的缓冲作用。
以上实施方式仅用以说明本申请的技术方案而非限制，尽管参照以上较佳实施方式对本申请进行了详细说明，本领域的普通技术人员应当理解，可以对本申请的技术方案进行修改或等同替换都不应脱离本申请技术方案的精神和范围。

Claims (10)

  1. 一种负极材料，所述负极材料包含硅复合颗粒，所述硅复合颗粒包含非晶硅颗粒和缓冲相，所述非晶硅颗粒分散在所述缓冲相中，其中，所述非晶硅颗粒分散在所述缓冲相中的非均匀度小于或等于30％。
  2. 根据权利要求1所述的负极材料，其中，所述非晶硅颗粒分散在所述缓冲相中的非均匀度小于或等于15％。
  3. 根据权利要求1所述的负极材料，其中，所述硅复合颗粒的球形度大于或等于0.50。
  4. 根据权利要求1所述的负极材料，其中，所述负极材料的比表面积小于或等于5m 2/g。
  5. 根据权利要求1所述的负极材料，其中，所述负极材料的粒度满足D90-D10≤15μm。
  6. 根据权利要求1所述的负极材料，其中，所述缓冲相包括碳、氧、硅、铁、钛、铝或者镉中的至少一种元素。
  7. 根据权利要求6所述的负极材料，其中，所述缓冲相包括一氧化硅或者二氧化硅中的至少一种。
  8. 根据权利要求1所述的负极材料，其中，所述硅复合颗粒还包含导电剂，所述导电剂分散在所述缓冲相中。
  9. 一种电化学装置，所述电化学装置包括负极极片，所述负极极片包括负极活性材料层，所述负极活性材料层包括权利要求1-8任意一项所述的负极材料。
  10. 一种电子装置，其中，所述电子装置包括权利要求9所述的电化学装置。
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CN117457880A (zh) * 2023-11-29 2024-01-26 贝特瑞新材料集团股份有限公司 负极材料及电池
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012178269A (ja) * 2011-02-25 2012-09-13 Toyota Industries Corp リチウムイオン二次電池用負極活物質、および、その負極活物質を用いたリチウムイオン二次電池
CN103779536A (zh) * 2013-11-06 2014-05-07 南京安普瑞斯有限公司 一种锂离子电池的含硅负极及其制备方法
CN104577081A (zh) * 2014-12-30 2015-04-29 华南理工大学 一种锂离子电池负极材料及其制备方法
CN104937751A (zh) * 2012-12-20 2015-09-23 尤米科尔公司 用于可再充电电池的负极材料及其生产方法
CN108630912A (zh) * 2018-03-11 2018-10-09 贵州格瑞特新材料有限公司 一种锂离子电池用硅碳负极材料及其制备方法

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4635409B2 (ja) * 2003-04-14 2011-02-23 株式会社Ｇｓユアサ 非水電解質電池
JP5219339B2 (ja) * 2006-02-28 2013-06-26 三洋電機株式会社 リチウム二次電池
US8431270B2 (en) * 2006-12-26 2013-04-30 Mitsubishi Chemical Corporation Composite graphite particles for nonaqueous secondary battery, negative-electrode material containing the same, negative electrode, and nonaqueous secondary battery
JP2010033830A (ja) * 2008-07-28 2010-02-12 Nec Tokin Corp 非水電解質二次電池用負極およびそれを用いた非水電解質二次電池
CN102637859B (zh) * 2012-04-06 2014-08-27 宁德新能源科技有限公司 锂离子电池及其石墨负极材料及其制备方法
KR20150006703A (ko) * 2013-07-09 2015-01-19 삼성정밀화학 주식회사 리튬이차전지용 음극 활물질, 이를 포함하는 음극용 조성물 및 리튬이차전지
CN107799728A (zh) * 2016-08-29 2018-03-13 南京安普瑞斯有限公司 一种用于锂离子电池的空心硅碳复合材料及其制备方法
KR102401839B1 (ko) * 2017-07-21 2022-05-25 에스케이온 주식회사 리튬 이차 전지용 음극 활물질, 이의 제조방법, 및 이를 포함하는 리튬 이차 전지
JP6619123B2 (ja) * 2017-12-28 2019-12-11 昭和電工株式会社 リチウムイオン二次電池用負極材
KR102542650B1 (ko) * 2018-04-20 2023-06-09 삼성에스디아이 주식회사 리튬 이차 전지용 음극 활물질 및 이를 포함하는 리튬 이차 전지
CN109346670A (zh) * 2018-10-19 2019-02-15 深圳中科瑞能实业有限公司 储能器件铝负极、储能器件及其制备方法
CN110165187A (zh) * 2019-06-05 2019-08-23 安普瑞斯（南京）有限公司 一种锂离子电池用硅碳二次颗粒材料及其制备方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012178269A (ja) * 2011-02-25 2012-09-13 Toyota Industries Corp リチウムイオン二次電池用負極活物質、および、その負極活物質を用いたリチウムイオン二次電池
CN104937751A (zh) * 2012-12-20 2015-09-23 尤米科尔公司 用于可再充电电池的负极材料及其生产方法
CN103779536A (zh) * 2013-11-06 2014-05-07 南京安普瑞斯有限公司 一种锂离子电池的含硅负极及其制备方法
CN104577081A (zh) * 2014-12-30 2015-04-29 华南理工大学 一种锂离子电池负极材料及其制备方法
CN108630912A (zh) * 2018-03-11 2018-10-09 贵州格瑞特新材料有限公司 一种锂离子电池用硅碳负极材料及其制备方法

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