WO2022193286A1 - Matériau d'électrode négative et son procédé de préparation, dispositif électrochimique et dispositif électronique - Google Patents

Matériau d'électrode négative et son procédé de préparation, dispositif électrochimique et dispositif électronique Download PDF

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WO2022193286A1
WO2022193286A1 PCT/CN2021/081795 CN2021081795W WO2022193286A1 WO 2022193286 A1 WO2022193286 A1 WO 2022193286A1 CN 2021081795 W CN2021081795 W CN 2021081795W WO 2022193286 A1 WO2022193286 A1 WO 2022193286A1
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negative electrode
electrode material
carbon fiber
silicon
porous carbon
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PCT/CN2021/081795
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English (en)
Chinese (zh)
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姜道义
陈志焕
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宁德新能源科技有限公司
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Priority to CN202180030956.4A priority Critical patent/CN115443559A/zh
Priority to PCT/CN2021/081795 priority patent/WO2022193286A1/fr
Publication of WO2022193286A1 publication Critical patent/WO2022193286A1/fr

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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
    • 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 present application relates to the technical field of anode materials, and in particular, to anode materials and preparation methods thereof, electrochemical devices and electronic devices.
  • silicon-based anode materials have a gram capacity as high as 1500mAh/g to 4200mAh/g, and are considered to be the most promising next-generation lithium-ion anode materials.
  • silicon due to the low electrical conductivity of silicon (>10 8 ⁇ .cm), and its volume expansion of about 300% during charge-discharge and the formation of an unstable solid electrolyte interface (SEI), the silicon anode material in the charge-discharge process It will be pulverized and dropped from the current collector, causing the loss of electrical contact between the active material and the current collector, resulting in poor electrochemical performance, capacity attenuation, and cycle stability, which hinders its further application to a certain extent.
  • SEI solid electrolyte interface
  • Nano-sized silicon-based anode materials and dispersed in carbon matrix can effectively improve the cycle performance of silicon-based anode materials. After granulation, carbonization is carried out to obtain the silicon-carbon composite material that is mainly used now. However, the cycle performance of this anode material is low and the expansion rate is relatively large.
  • the present application proposes a negative electrode material and a preparation method thereof, an electrochemical device and an electronic device.
  • the negative electrode material can effectively alleviate the expansion of the negative electrode due to the expansion of the silicon base and graphite, thereby improving the cycle performance of the negative electrode material.
  • the present application provides a negative electrode material
  • the negative electrode material includes a porous carbon fiber skeleton and a silicon-based material filled inside the porous carbon fiber skeleton; wherein the porous carbon fiber skeleton has a diameter of 0.5um to 5um, and The aspect ratio of the porous carbon fiber skeleton is 5 to 100.
  • the negative electrode material further includes a carbon layer.
  • the thickness of the carbon layer is 1 nm to 100 nm.
  • the negative electrode material satisfies at least one of the following conditions (1) to (4):
  • the mass percentage content of silicon in the negative electrode material is 5% to 50%;
  • the mass percentage content of carbon in the negative electrode material is 50% to 95%
  • the specific surface area of the negative electrode material is less than 50 m 2 /g
  • the powder true density of the negative electrode material is 2.0 g/cm 3 to 2.3 g/cm 3 .
  • the highest intensity value of the diffraction peak attributable to 28.4° ⁇ 0.2° is M, which is attributable to 45° ⁇ 0.5°.
  • the highest intensity value of the diffraction peak is N, where M/N ⁇ 1.
  • an embodiment of the present application provides a method for preparing a negative electrode material, the method comprising the following steps:
  • the mixed solution is prepared into a polymer fiber of 0.2um to 10um by a spinning process
  • the diameter of the porous carbon fiber skeleton is 0.5um to 5um, and the aspect ratio of the porous carbon fiber skeleton is 5 to 100;
  • a carbon source gas is passed into the silicon-loaded carbon fiber material to carry out secondary vapor deposition to obtain the negative electrode material.
  • the present application provides a negative electrode sheet, comprising a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector, the negative electrode active material layer comprising the negative electrode material described in the first aspect or the second negative electrode material layer.
  • the present application provides an electrochemical device, comprising a negative electrode active material layer, the negative electrode active material layer comprising the negative electrode material described in the first aspect or the negative electrode material prepared by the method for preparing the negative electrode material described in the second aspect .
  • the electrochemical device is a lithium-ion battery.
  • the present application provides an electronic device comprising the electrochemical device of the fourth aspect.
  • the present application at least has the following beneficial effects:
  • the negative electrode material provided by the present application by controlling the size of the porous carbon fiber skeleton and the aspect ratio of the porous carbon fiber skeleton, the silicon-based material is deposited into the porous carbon fiber skeleton, and the porous carbon fiber skeleton is used as the supporting skeleton of the negative electrode material.
  • the pores can alleviate a certain volume expansion, and the fibrous support skeleton can effectively increase the long-range electrical contact of the silicon-based negative electrode material relative to the granular carbon skeleton, which can effectively alleviate the expansion of the negative electrode due to the expansion of the silicon-based material and the graphite. Improve the cycle performance of anode active materials.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with any other lower limit to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range.
  • every point or single value between the endpoints of a range is included within the range, even if not expressly recited.
  • each point or single value may serve as its own lower or upper limit in combination with any other point or single value or with other lower or upper limits to form a range not expressly recited.
  • an embodiment of the present application provides a negative electrode material, the negative electrode material includes a porous carbon fiber skeleton and a silicon-based material filled inside the porous carbon fiber skeleton; wherein the porous carbon fiber skeleton has a diameter of 0.5 ⁇ m to 5um, and the aspect ratio of the porous carbon fiber skeleton is 5 to 100.
  • the negative electrode material provided by the present application by controlling the size of the porous carbon fiber skeleton and the aspect ratio of the porous carbon fiber skeleton, the silicon-based material is deposited into the porous carbon fiber skeleton, and the porous carbon fiber skeleton is used as the supporting skeleton of the negative electrode material.
  • the pores can alleviate a certain volume expansion, and the fibrous support skeleton can effectively increase the long-range electrical contact of the silicon-based negative electrode relative to the granular skeleton, which can effectively alleviate the expansion of the negative electrode due to the expansion of the silicon-based material and the graphite, thereby improving the negative electrode. Cycling performance of active materials.
  • the diameter of the porous carbon fiber skeleton can be specifically 0.5um, 0.7um, 1.4um, 1.5um, 1.6um, 3.2um, 5.0um, etc., of course, it can also be within the above range. Other values are not limited here.
  • the aspect ratio of the porous carbon fiber skeleton can be specifically 5, 5.5, 6.4, 6.6, 6.9, 7.0, 8.0, 12.8, 13, 20, 50, or 100, and of course can also be other values within the above range, which is not specified here. Do limit. When the diameter of the porous carbon fiber skeleton is too large, the aspect ratio will be too small. If the aspect ratio is too small, there will be fewer contact sites between the silicon composite material and the graphite. In the process of silicon expansion, it is easy to cause silicon The electrical contact with the graphite fails, thereby deteriorating the cycle performance of the cell.
  • the highest intensity value of the diffraction peak attributable to 28.4° ⁇ 0.2° is M
  • the highest intensity value of the diffraction peak attributable to 45° ⁇ 0.5° is M.
  • the value is N, where M/N ⁇ 1.
  • the diffraction peak attributable to the vicinity of 28.4° is the diffraction peak formed by silicon particles of crystalline silicon
  • the diffraction peak attributable to the vicinity of 45° is the diffraction peak formed by carbon
  • the carbon peak is used as a reference to limit the silicon peak growth.
  • the negative electrode material further includes a carbon layer, and the thickness of the carbon layer is 1 nm to 100 nm. It is understandable that if the carbon layer is too thick, the lithium ion transmission efficiency is reduced, which is not conducive to the high-rate charge and discharge of the material, and the comprehensive performance of the negative electrode material is reduced. Weak performance, resulting in poor performance for long loops.
  • the thickness of the carbon layer is 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm or 100 nm, etc.
  • it can also be other values within the above range, which is not limited here. .
  • the mass percentage content of silicon element in the negative electrode material is 5% to 50%; %, etc., but are not limited to the recited values, and other unrecited values within the numerical range are also applicable. If the silicon content is too high, the volume expansion rate of the lithium-ion battery will increase, which is not conducive to improving the cycle stability; if the silicon content is too low, the first effect and rate performance of the lithium-ion battery will be affected.
  • the mass percentage content of carbon element in the negative electrode material is 50% to 95%; %, etc., but are not limited to the recited values, and other unrecited values within the numerical range are also applicable. If the carbon content is too high, the lithium ion transmission efficiency is reduced, which is not conducive to the high-rate charge and discharge of the material, and the comprehensive performance of the negative electrode material is reduced. Weak, resulting in long-cycle performance spreads.
  • the specific surface area of the negative electrode material is less than 50m 2 /g; specifically, it can be 1.50m 2 /g, 2.00m 2 /g, 5.0m 2 /g, 10.0m 2 /g, 15m 2 /g, 20m 2 /g, 30m 2 /g or 40m 2 /g, etc., but are not limited to the recited values, and other unrecited values within the range of values are also applicable.
  • the specific surface area of the negative electrode material is within the above range, which ensures the processing performance of the material, is conducive to improving the primary efficiency of the lithium battery made of the negative electrode material, and is conducive to improving the cycle performance of the negative electrode material.
  • the specific surface area of the negative electrode material is 2.6 m 2 /g to 28 m 2 /g, and further preferably, the specific surface area of the negative electrode material is 2.6 m 2 /g to 5.2 m 2 /g.
  • the true powder density of the negative electrode material is 2.0 g/cm 3 to 2.3 g/cm 3 . Specifically, it can be 2.0g/cm 3 , 2.05g/cm 3 , 2.1g/cm 3 , 2.15g/cm 3 , 2.2g/cm 3 , 2.25g/cm 3 or 2.3g/cm 3 , etc., but not Not limited to the recited values, other non-recited values within this range of values are equally applicable.
  • the true density of the negative electrode material is within the above range, which is beneficial to improve the energy density of the lithium battery made of the negative electrode material.
  • the true density of the above-mentioned powder is to place a certain mass of powder samples in a true density tester, close the test system, and pass helium or nitrogen into the test system according to the program.
  • the true volume so as to calculate the true density of the powder.
  • the present application provides a method for preparing a negative electrode material, the method comprising the following steps:
  • the mixed solution is prepared into a polymer fiber of 0.2um to 10um by a spinning process
  • the diameter of the porous carbon fiber skeleton is 0.5um to 5um, and the aspect ratio of the porous carbon fiber skeleton is 5 to 100;
  • a silicon source gas is introduced into the porous carbon fiber skeleton, and a vapor deposition is performed to obtain a silicon-loaded carbon fiber material;
  • a carbon source gas is passed into the silicon-loaded carbon fiber material to carry out secondary vapor deposition to obtain the negative electrode material.
  • silicon is deposited into the porous carbon fiber skeleton by thermal decomposition of the silicon source gas.
  • the fibrous carbon skeleton can effectively increase the long-range electrical contact of the silicon-based negative electrode material, which can effectively alleviate the The expansion of the silicon base and graphite leads to the expansion of the negative electrode, which can effectively improve the cycle performance of the negative electrode active material.
  • Step S10 the porogen and acrylonitrile are dispersed in dimethylacrylamide to form a mixed solution.
  • the porogen is calcium carbonate, and the particle size of the calcium carbonate particles is 10 nm to 20 nm. Specifically, it can be 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm or 20 nm, and of course other values within the above range are also possible.
  • the porogen can adhere to the polymer fibers, and then through the acid washing treatment, a porous structure is formed.
  • the molecular weight of the acrylonitrile is 100w to 1000w; specifically, it can be 100w, 150w, 200w, 300w, 400w, 500w, 600w, 700w, 800w or 1000w, etc., of course, it can also be in the above range other values within.
  • step S20 the mixed solution is prepared into a polymer fiber of 0.2 um to 10 um by a spinning process.
  • the spinning process includes at least one of electrospinning, liquid-phase spinning, and melt spinning.
  • Step S30 carbonizing, crushing and pickling the polymer fibers to obtain the porous carbon fiber skeleton, the diameter of the porous carbon fiber skeleton is 0.5um to 5um, and the aspect ratio of the porous carbon fiber skeleton is 5 to 100.
  • the long-range electrical contact of the silicon-based anode material can be effectively increased, the expansion of the anode caused by the expansion of the silicon-based and graphite can be effectively alleviated, and the cycle performance of the anode active material can be effectively improved.
  • the steps of the carbonization treatment include:
  • the polymer fibers are oxidized in air at 200°C to 300°C for 2h to 10h, and then placed in an argon atmosphere at 600°C to 1200°C for high temperature carbonization for 2h to 12h.
  • the acrylonitrile can undergo a ring-forming reaction, which is beneficial to the formation of a more stable carbon fiber material after heat treatment.
  • the polymer fibers are carbonized to form carbon fibers, and the carbon fibers can be used as the skeleton structure of the negative electrode active material, which can improve the cycle stability of the negative electrode active material.
  • the crushing treatment includes at least one of ball milling, wet sand milling or high-speed jet milling. It can be understood that the crushing process can obtain carbon fiber materials of different lengths, and further control the aspect ratio of the porous carbon fiber skeleton.
  • the acid solution used in the pickling treatment is hydrochloric acid or hydrofluoric acid. It can be understood that hydrochloric acid or hydrofluoric acid can react with the porogen attached to the carbon fiber, so that the porogen can be dissolved in the hydrochloric acid or hydrofluoric acid, so that the carbon fiber forms a pore structure.
  • the porogen is nanoscale particles, the pore structure formed on the carbon fiber is also nanoscale.
  • step S40 a silicon source gas is introduced into the porous carbon fiber skeleton, and a vapor deposition is performed to obtain a silicon-loaded carbon fiber material;
  • one vapor deposition is silicon deposition, and silicon is deposited into the carbon fiber skeleton to form nano-silicon. Since the pore structure of the carbon fiber is also nano-scale, the silicon aggregation area on the carbon fiber skeleton can be effectively controlled to be less than 20 nm, and the nano-pore structure can be effectively controlled. It can also alleviate the volume expansion of silicon, thereby improving the cycling performance of silicon-based materials.
  • the silicon source gas is silane.
  • the deposition temperature of the primary vapor deposition is 500°C to 900°C, specifically 500°C, 550°C, 600°C, 650°C, 700°C, 800°C or 900°C, etc.
  • 500°C, 550°C, 600°C, 650°C, 700°C, 800°C or 900°C is 500°C to 900°C, specifically 500°C, 550°C, 600°C, 650°C, 700°C, 800°C or 900°C, etc.
  • Other values within the above ranges are also possible.
  • the deposition time of the primary vapor deposition is 0.25h to 24h; specifically, it may be 0.25h, 0.5h, 1h, 2h, 3h, 6h, 8h, 12h, 16h, 18h or 24h, etc. , of course other values within the above range are also possible.
  • step S50 a carbon source gas is introduced into the silicon-loaded carbon fiber material, and secondary vapor deposition is performed to obtain the negative electrode material.
  • the carbon source gas includes at least one of methane, acetylene, propane or ethylene.
  • the deposition temperature of the secondary vapor deposition is 500°C to 950°C, specifically 500°C, 550°C, 600°C, 650°C, 700°C, 800°C, 900°C or 950°C
  • °C the deposition temperature of the secondary vapor deposition
  • the deposition time of the secondary vapor deposition is 0.5h to 12h; specifically, it can be 0.5h, 1h, 2h, 3h, 6h, 8h, 10h or 12h, etc., of course, it can also be the above-mentioned other values in the range.
  • an embodiment of the present application provides a negative electrode sheet, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector, the negative electrode active material layer comprises the negative electrode active material layer according to the first aspect of the present application negative electrode material.
  • the negative electrode active material layer includes a binder
  • the binder includes polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic The (esterified) styrene-butadiene rubber, epoxy resin, nylon, etc., are not limited here.
  • the negative electrode active material layer further includes a conductive material
  • the conductive material includes natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, metal powder, metal fiber, copper, nickel, aluminum , silver or polyphenylene derivatives, etc., are not limited here.
  • the negative electrode current collector includes, but is not limited to, copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, foamed copper or a polymer substrate coated with conductive metal.
  • the present application further provides an electrochemical device, comprising a negative electrode active material layer, the negative electrode active material layer comprising the negative electrode material described in the first aspect or the method for preparing the negative electrode material described in the second aspect above. obtained negative electrode material.
  • the electrochemical device further includes a positive electrode plate, and the positive electrode plate includes a positive electrode current collector and a positive electrode active material layer located on the positive electrode current collector.
  • the positive active material includes at least one of lithium cobalt oxide (LiCoO2), lithium nickel manganese cobalt ternary material, lithium iron phosphate, lithium manganese iron phosphate, and lithium manganate.
  • LiCoO2 lithium cobalt oxide
  • LiN lithium nickel manganese cobalt ternary material
  • iron phosphate lithium manganese iron phosphate
  • manganate lithium manganate
  • the positive electrode active material layer further includes a binder and a conductive material.
  • the binder improves the bonding of the positive electrode active material particles to each other, and also improves the bonding of the positive electrode active material to the current collector.
  • the binder includes polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone , at least one of polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin or nylon.
  • the conductive material includes carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof.
  • the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, or any combination thereof.
  • the metal-based material is selected from metal powders, metal fibers, copper, nickel, aluminum, or silver.
  • the conductive polymer is a polyphenylene derivative.
  • the positive electrode current collector includes, but is not limited to, aluminum foil.
  • the electrochemical device further includes an electrolyte, and the electrolyte includes an organic solvent, a lithium salt and an additive.
  • the organic solvent of the electrolytic solution according to the present application may be any organic solvent known in the prior art that can be used as a solvent of the electrolytic solution.
  • the electrolyte used in the electrolyte solution according to the present application is not limited, and it may be any electrolyte known in the prior art.
  • the additive for the electrolyte according to the present application may be any additive known in the art as an additive for the electrolyte.
  • the organic solvent includes, but is not limited to: ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate or ethyl propionate.
  • the lithium salt includes at least one of an organic lithium salt or an inorganic lithium salt.
  • the lithium salts include, but are not limited to: lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), bistrifluoromethanesulfonimide Lithium LiN(CF 3 SO 2 ) 2 (LiTFSI), Lithium Bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), Lithium Bisoxalate Borate LiB(C 2 O 4 ) 2 (LiBOB) ) or lithium difluorooxalate borate LiBF 2 (C 2 O 4 ) (LiDFOB).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiPO 2 F 2 lithium difluorophosphate
  • LiPFSI bistrifluoromethanesulfonimide Lithium LiN(CF 3 SO
  • the concentration of the lithium salt in the electrolyte may be 0.5 mol/L to 3 mol/L.
  • the electrochemical device of the present application includes, but is not limited to: all kinds of primary batteries, secondary batteries, fuel cells, solar cells or capacitors.
  • the electrochemical device is a lithium secondary battery, wherein the lithium secondary battery includes, but is not limited to, a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion secondary battery polymer secondary battery.
  • an embodiment of the present application further provides an electronic device, where the electronic device includes the electrochemical device described in the fourth aspect.
  • the electronic devices include, but are not limited to: notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, etc. stereo headphones, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power, motors, cars, motorcycles, power Bicycles, bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries or lithium-ion capacitors, etc.
  • lithium-ion batteries The preparation of lithium-ion batteries is described below by taking lithium-ion batteries as an example and combining with specific examples.
  • the mixed solution is prepared into a polymer fiber of 0.2um to 10um by a spinning process
  • the polymer fibers are oxidized in air at 250°C for 5 hours, then carbonized at high temperature, and sintered at 1000°C for 8 hours in an inert atmosphere, and then crushed and pickled to obtain a porous carbon fiber skeleton;
  • Examples 1 to 9 were prepared according to the above method, and the specific parameters of Examples 1 to 9 are shown in Table 1 below.
  • Comparative Example 1 was prepared according to the above method.
  • the aspect ratio of the prepared porous carbon fiber skeleton of Comparative Example 1 was 1.0.
  • the specific parameters of Comparative Example 1 are shown in Table 1 below.
  • the selected test instrument was: OXFORD EDS (X-max-20mm 2 ), the acceleration voltage was 10KV to adjust the focus, and the observation magnification was from 50K for high magnification observation and low magnification. From 500 to 2000, the particle agglomeration is mainly observed.
  • the adsorption amount of the sample monolayer is calculated based on the Brownnauer-Etter-Taylor adsorption theory and its formula (BET formula), and then calculate The specific surface area of a solid.
  • the sample is heated and burned at high temperature in a high-frequency furnace under oxygen-rich conditions to oxidize carbon and sulfur into carbon dioxide and sulfur dioxide. .
  • This signal is sampled by the computer, converted into a value proportional to the concentration of carbon dioxide and sulfur dioxide after linear correction, and then the value of the whole analysis process is accumulated. After the analysis, the accumulated value is divided by the weight value in the computer, and then multiplied by Correction coefficient, subtract the blank, you can obtain the percentage of carbon and sulfur in the sample.
  • Samples were tested using a high-frequency infrared carbon-sulfur analyzer (Shanghai Dekai HCS-140).
  • the positive active material lithium cobalt oxide (LiCoO 2 ), conductive carbon black, and binder polyvinylidene fluoride are mixed according to the weight ratio of 95:2.5:2.5, and N-methylpyrrolidone (NMP) is added.
  • NMP N-methylpyrrolidone
  • the negative electrode materials, graphite, conductive agent (conductive carbon black, Super ) and binder PAA are mixed according to the weight ratio of 70:15:5:10, deionized water is added, and the negative electrode slurry is obtained under the action of a vacuum mixer; the negative electrode slurry is uniformly coated on the negative electrode current collector copper foil; The copper foil is dried, then subjected to cold pressing, cutting and slitting, and then dried under vacuum conditions to obtain a negative electrode sheet.
  • a polyethylene porous polymer film is used as the separator.
  • the positive electrode, the separator and the negative electrode in order, so that the separator is placed between the positive and negative electrode sheets to isolate them, and then wind them to obtain a bare cell; after welding the tabs, place the bare cell on the outer packaging foil aluminum
  • the above-prepared electrolyte is injected into the dried bare cell, and the lithium-ion battery is obtained through the processes of vacuum packaging, standing, chemical formation, shaping, and capacity testing.
  • the lithium-ion battery that has reached a constant temperature is charged with a constant current of 0.7C to a voltage of 4.4V, and then charged with a constant voltage of 4.4V to a current of 0.025C. After standing for 5 minutes, it is discharged with a constant current of 0.5C to a voltage of 3.0V.
  • the capacity obtained in this step is the initial capacity, and 0.7C charge/0.5C discharge is carried out for cycle test, and the capacity decay curve is obtained by taking the ratio of the capacity in each step to the initial capacity.
  • the room temperature cycle performance of the battery was recorded as the number of cycles from 25°C to 90% of the capacity retention rate, and the number of cycles from 45°C to 80% of the capacity retention rate was recorded as the high-temperature cycle performance of the battery.
  • the number of cycles in each case compares the cycle performance of the materials.
  • the lithium-ion battery that has reached a constant temperature is discharged with a constant current of 0.2C to a voltage of 3.0V, left for 5 minutes, charged with a constant current of 0.5C to a voltage of 4.45V, and then charged with a constant voltage of 4.45V to a current of 0.05C and then left to stand. 5min, adjust the discharge rate, conduct the discharge test at 0.2C, 0.5C, 1C, 1.5C, 2.0C, respectively, to obtain the discharge capacity, and compare the capacity obtained at each rate with the capacity obtained at 0.2C. The ratio at 0.2C compares rate performance.
  • the gram capacity in this application form is the gram capacity with a discharge cut-off voltage of 2.0V;
  • the first efficiency calculation method in this application form is the capacity corresponding to the discharge cut-off voltage of 2.0V/the capacity corresponding to the charge voltage cut-off to 0.005V.
  • Example 1 500 5.3% 420 6.0%
  • Example 2 480 5.8% 390 6.2%
  • Example 3 450 6.2%
  • Comparative Example 1 380 6.4% 350 7.2%
  • the mass percentage content of silicon in the negative electrode material is 17.2% to 39%.
  • the diameter of the porous carbon fiber skeleton adopted in Example 4 is 1.5um
  • the diameter of the porous carbon fiber skeleton adopted in Example 5 is 3.2um
  • the The diameter of the carbon fiber skeleton is 5.1 um
  • the aspect ratio of the porous carbon fiber skeleton of Examples 4 to 6 is in the range of 5.4 to 6.9
  • the silicon content and carbon content of the negative electrode material are similar. It can be seen that when the diameter of the porous carbon fiber skeleton is greater than 5um, the cyclability of the lithium-ion battery will decrease instead. Therefore, the diameter of the porous carbon fiber skeleton should be controlled to be 0.5um to 5um.

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Abstract

La présente demande concerne un matériau d'électrode négative et son procédé de préparation, un dispositif électrochimique et un dispositif électronique. Le matériau d'électrode négative comprend un squelette de fibre de carbone poreux et un matériau à base de silicium remplissant l'intérieur du squelette de fibre de carbone poreux, le diamètre du squelette de fibre de carbone poreux étant de 0,5 µm à 5 µm, et un rapport longueur sur diamètre du squelette de fibre de carbone poreux étant de 5 à 100. Le matériau d'électrode négative fourni par la présente demande peut atténuer efficacement l'expansion de l'électrode négative due à la dilatation du silicium et du graphite, améliorant ainsi les performances de cycle du matériau d'électrode négative.
PCT/CN2021/081795 2021-03-19 2021-03-19 Matériau d'électrode négative et son procédé de préparation, dispositif électrochimique et dispositif électronique WO2022193286A1 (fr)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116207243A (zh) * 2023-02-22 2023-06-02 胜华新材料集团股份有限公司 一种纤维状硅碳复合材料及其制备方法
CN117096330A (zh) * 2023-10-20 2023-11-21 宁德时代新能源科技股份有限公司 硅碳复合材料及其制备方法、二次电池和用电装置
CN117438558A (zh) * 2023-10-23 2024-01-23 柔电（武汉）科技有限公司 一种硅碳负极及其制备方法
WO2024092569A1 (fr) * 2022-11-02 2024-05-10 宁德时代新能源科技股份有限公司 Matériau actif d'électrode négative et son procédé de préparation, batterie secondaire comprenant celui-ci et dispositif électrique
CN117438558B (zh) * 2023-10-23 2024-05-24 柔电（武汉）科技有限公司 一种硅碳负极及其制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117059765A (zh) * 2023-08-04 2023-11-14 江门市和创新能源材料有限公司 一种硅碳复合材料及其制备方法和应用

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103311523A (zh) * 2013-06-04 2013-09-18 清华大学深圳研究生院 具有纳米微孔隙的硅碳复合材料及其制备方法与用途
CN105118974A (zh) * 2015-08-20 2015-12-02 浙江理工大学 一种硅基负极材料及其制备方法
CN105552304A (zh) * 2014-10-28 2016-05-04 乔治洛德方法研究和开发液化空气有限公司 硅/碳复合物、硅合金/碳复合物及其制备方法
CN111074382A (zh) * 2019-12-20 2020-04-28 银隆新能源股份有限公司 硅碳复合材料、其制备方法、锂离子电池用硅基负极及锂离子电池

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012022933A (ja) * 2010-07-15 2012-02-02 Jfe Chemical Corp 二次電池用負極材料、リチウムイオン二次電池用負極およびリチウムイオン二次電池
JP6181590B2 (ja) * 2014-04-02 2017-08-16 信越化学工業株式会社 非水電解質二次電池用負極及び非水電解質二次電池
KR102060353B1 (ko) * 2018-04-10 2019-12-30 충남대학교산학협력단 이차전지 음극 제조용 슬러리 조성물, 이의 제조방법, 이를 포함하는 이차전지용 음극 및 리튬 이차 전지
CN110729460B (zh) * 2019-09-30 2023-06-30 山东玉皇新能源科技有限公司 一种锂离子电池纳米硅复合补锂负极材料及其制备方法与应用
CN111146428B (zh) * 2020-01-02 2021-06-29 宁德新能源科技有限公司 负极和包含其的电化学装置及电子装置
CN112054203A (zh) * 2020-09-15 2020-12-08 昆山宝创新能源科技有限公司 自支撑锂金属负极材料及其制备方法和应用

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103311523A (zh) * 2013-06-04 2013-09-18 清华大学深圳研究生院 具有纳米微孔隙的硅碳复合材料及其制备方法与用途
CN105552304A (zh) * 2014-10-28 2016-05-04 乔治洛德方法研究和开发液化空气有限公司 硅/碳复合物、硅合金/碳复合物及其制备方法
CN105118974A (zh) * 2015-08-20 2015-12-02 浙江理工大学 一种硅基负极材料及其制备方法
CN111074382A (zh) * 2019-12-20 2020-04-28 银隆新能源股份有限公司 硅碳复合材料、其制备方法、锂离子电池用硅基负极及锂离子电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
QU ERLI, CHEN TAO, XIAO QIZHEN, LEI GANGTIE, LI ZHAOHUI: "Freestanding silicon/carbon nanofibers composite membrane as a flexible anode for Li-Ion battery", JOURNAL OF POWER SOURCES, ELSEVIER, AMSTERDAM, NL, vol. 403, 1 November 2018 (2018-11-01), AMSTERDAM, NL, pages 103 - 108, XP055968115, ISSN: 0378-7753, DOI: 10.1016/j.jpowsour.2018.09.086 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024092569A1 (fr) * 2022-11-02 2024-05-10 宁德时代新能源科技股份有限公司 Matériau actif d'électrode négative et son procédé de préparation, batterie secondaire comprenant celui-ci et dispositif électrique
CN116207243A (zh) * 2023-02-22 2023-06-02 胜华新材料集团股份有限公司 一种纤维状硅碳复合材料及其制备方法
CN117096330A (zh) * 2023-10-20 2023-11-21 宁德时代新能源科技股份有限公司 硅碳复合材料及其制备方法、二次电池和用电装置
CN117438558A (zh) * 2023-10-23 2024-01-23 柔电（武汉）科技有限公司 一种硅碳负极及其制备方法
CN117438558B (zh) * 2023-10-23 2024-05-24 柔电（武汉）科技有限公司 一种硅碳负极及其制备方法

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