Carbon black material, negative pole piece, and secondary battery and device comprising negative pole piece

Abstract

The invention provides a carbon black material, a negative pole piece, a secondary battery comprising the negative pole piece and a device. The carbon black material meets the condition that ID / IG is 1.6-2.3, and ID / IG refers to the peak area ratio of a D peak to a G peak of the carbon black material. The high-defect-degree carbon black material provided by the invention has more active sites and larger specific surface area, so that the lithium intercalation capacity and the electrochemical performance are further improved. The carbon black material is used as a conductive material of the negative electrode plate, can form a conductive network, provides an electron transmission path for a negative electrode active material, has relatively high lithium intercalation capacity, also can play a role of a carbon active material, supplements the specific capacity of the negative electrode plate, effectively improves the total capacity and energy density of the negative electrode plate, and improves the performance of the negative electrode plate. And the first-circle coulombic efficiency of the secondary battery is ensured.

Description

Technical Field

[0001] The present application relates to the field of energy storage, and particularly to a carbon black material, a negative electrode sheet, a secondary battery and a device including the same. Background Art

[0002] In the field of electric vehicles, the energy density of lithium-ion batteries is crucial for increasing the driving range of electric vehicles. The specific capacity of the negative electrode sheet is one of the key factors affecting the energy density of lithium-ion batteries. Currently, the negative electrode sheet generally consists of a negative electrode active material, a conductive agent, a binder and a current collector. Among them, the main function of the conductive agent is to form a conductive network and provide an electron transport path for the negative electrode active material. Due to its advantages such as dense conductive network, simple processing and low cost, carbon black has been widely used as a conductive agent material. However, as a carbon material, carbon black has the ability of lithium intercalation capacity. In the voltage range of 0.005V to 1.5V, the carbon black material can generally provide a specific capacity of 100mAh / g to 250mAh / g. Compared with the specific capacity of 340mAh / g to 360mAh / g of the main graphite material, its specific capacity is relatively low and it cannot effectively improve the overall capacity and energy density of the negative electrode sheet.

[0003] Therefore, developing a novel carbon black material with improved specific capacity and electrochemical performance, so as to improve the specific capacity and energy density of the negative electrode sheet, is of great significance for increasing the driving range of electric vehicles. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the present application provides a carbon black material, a negative electrode sheet, a secondary battery and a device including the same. The carbon black material provided by the present application satisfies: I D / I G is 1.6 to 2.3. This carbon black material has more active sites and a larger specific surface area, thus having a higher lithium intercalation capacity and electrochemical performance.

[0005] The first aspect of the present application provides a carbon black material, which satisfies: I D / I G is 1.6 to 2.3, wherein, I D / I G refers to the peak area ratio of the D peak to the G peak of the carbon black material.

[0006] The second aspect of the present application provides a preparation method of carbon black, including: a step of ball-milling carbon black raw materials to obtain the carbon black material.

[0007] The third aspect of the present application provides a negative electrode sheet, which includes a negative electrode active material layer, and the negative electrode active material layer includes the carbon black material of the first aspect or the carbon black material prepared according to the preparation method of the second aspect.

[0008] A fourth aspect of the present application provides a secondary battery, which includes a positive electrode plate, an electrolyte, a separator, and the aforementioned negative electrode plate.

[0009] A fifth aspect of the present application provides a device, which includes the aforementioned secondary battery.

[0010] The technical solution of the present application can achieve the following beneficial effects:

[0011] The carbon black material proposed in the present application satisfies: I D / I G is 1.6 to 2.3. This carbon black material has more active sites, a larger specific surface area, a higher specific capacity, and high surface disorder characteristics, significantly improving the lithium intercalation capacity and electrochemical performance. As a conductive material for the negative electrode plate, this carbon black material can form a conductive network, provide an electron transport path for the negative electrode active material, and at the same time has a high lithium intercalation capacity, and can also act as a carbon active material to supplement the specific capacity of the negative electrode plate, effectively improving the overall capacity and energy density of the negative electrode plate, and ensuring the Coulomb efficiency of the first cycle of the secondary battery. Specific Embodiments

[0012] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. The embodiments described herein are illustrative in nature and are used to provide a basic understanding of the present application. The embodiments of the present application should not be construed as a limitation of the present application.

[0013] For the sake of brevity, only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form a range not explicitly recited; and any lower limit can be combined with other lower limits to form a range not explicitly recited, and similarly any upper limit can be combined with any other upper limit to form a range not explicitly recited. In addition, each individually disclosed point or single numerical value itself can be used as a lower limit or upper limit and combined with any other point or single numerical value or combined with other lower limits or upper limits to form a range not explicitly recited.

[0014] In the description herein, unless otherwise specified, "above" and "below" include the recited number.

[0015] Unless otherwise specified, the terms used in the present application have the well-known meanings commonly understood by those skilled in the art. Unless otherwise specified, the numerical values of the various parameters mentioned in the present application can be measured by various commonly used measurement methods in the art (for example, they can be tested according to the methods given in the embodiments of the present application).

[0016] The list of items connected by terms such as "at least one of", "at least one", "at least one kind of" or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single component or multiple components. Item B may include a single component or multiple components. Item C may include a single component or multiple components.

[0017] Carbon black material

[0018] One or more embodiments of the present application provide a carbon black material that satisfies: I D / I G is 1.6 to 2.3, where I D / I G refers to the peak area ratio of the D peak to the G peak of the carbon black material.

[0019] The carbon black material proposed in the present application satisfies: I D / I G is 1.6 to 2.3, I D refers to the intensity of the C lattice defect peak, I G refers to the intensity of the in-plane stretching vibration peak of C atom sp2 hybridization. The carbon black material that satisfies this condition has more active sites, a larger specific surface area, a higher specific capacity, and high surface disorder characteristics, further improving the lithium intercalation capacity and electrochemical performance. As a conductive agent for the negative electrode sheet, this carbon black material can form a conductive network, provide an electron transport path for the negative electrode active material, and at the same time have a high lithium intercalation capacity, and can play the role of a carbon active material to supplement the specific capacity of the negative electrode sheet, effectively improving the overall capacity and energy density of the negative electrode sheet, and ensuring the first-cycle Coulomb efficiency of the secondary battery.

[0020] In some embodiments, I D / I G is 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3 or a range composed of any two of the above values. In some embodiments, the defect degree I D / I G of the carbon black material is 1.6 to 2.1.

[0021] In some embodiments, the specific capacity of the carbon black material is from 310 mAh / g to 450 mAh / g. When the capacity of the carbon black material is too low, it cannot effectively supplement the specific capacity of the electrode sheet; when the capacity of the carbon black material is too high, the proportion of oxygen functional groups and defects in the carbon black material is too high, which will reduce the first efficiency of the electrode sheet. In some embodiments, the specific capacity of the carbon black material is 310 mAh / g, 320 mAh / g, 330 mAh / g, 340 mAh / g, 350 mAh / g, 360 mAh / g, 370 mAh / g, 380 mAh / g, 390 mAh / g, 400 mAh / g, 410 mAh / g, 420 mAh / g, 430 mAh / g, 440 mAh / g, 450 mAh / g or the range composed of any two of the above values. In some embodiments, the specific capacity of the carbon black material is from 320 mAh / g to 405 mAh / g.

[0022] In some embodiments, the specific surface area of the carbon black material is 100 m 2 / g to 350 m 2 / g. Within this range, the larger the specific surface area of the carbon black material, the higher the surface disorder degree, the richer the oxygen functional groups, and the higher its specific capacity, and it has better lithium intercalation performance. Exemplarily, the specific surface area of the carbon black material is 100 m 2 / g, 110 m 2 / g, 120 m 2 / g, 130 m 2 / g, 140 m 2 / g, 150 m 2 / g, 160 m 2 / g, 170 m 2 / g, 180 m 2 / g, 190 m 2 / g, 200 m 2 / g, 210 m 2 / g, 220 m 2 / g, 230 m 2 / g, 240 m 2 / g, 250 m 2 / g, 260 m 2 / g, 270 m 2 / g, 280 m 2 / g, 290 m 2 / g, 300 m 2 / g, 310 m 2 / g, 320 m 2 / g, 330 m 2 / g, 340 m 2 / g, 350 m 2 / g or a range composed of any two of the above values. In some embodiments, the specific surface area of the carbon black material is 110 m 2 / g to 315 m 2 / g.

[0023] In some embodiments, the carbon black material has oxygen-containing functional groups on its surface. Based on the mass of the carbon black material, the mass percentage content of the oxygen-containing functional groups is 5% to 30%. Within this range, the higher the content of the oxygen-containing functional groups, the more active sites for lithium intercalation in the carbon black, and thus a higher specific capacity and energy density are contributed in the negative electrode sheet. In some embodiments, the mass percentage content of the oxygen-containing functional groups is 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% or a range composed of any two of the above values. In some embodiments, the mass percentage content of the oxygen-containing functional groups is 10% to 20%.

[0024] In some embodiments, the oxygen-containing functional groups include at least one of C-O, C=O, and O-C=O.

[0025] Preparation method of carbon black material

[0026] One or more embodiments of the present application provide a preparation method of the aforementioned carbon black material. The preparation method includes: a step of ball milling the carbon black raw material. By means of mechanical high-energy ball milling in the present application, the microcrystalline graphite layer of the carbon black is disordered, the surface defect degree becomes higher, and at the same time, the carbon layer on the surface of the carbon black reacts with oxygen in the air to form oxygen-containing functional groups, thereby increasing the active sites for lithium intercalation in the carbon black, contributing a higher specific capacity and energy density in the negative electrode sheet, and further ensuring the first-cycle Coulombic efficiency of the secondary battery.

[0027] In some embodiments, the specific surface area of the carbon black raw material is 40 m 2 / g to 180 m 2 / g. In some embodiments, the specific surface area of the carbon black raw material is 40 m 2 / g, 50 m 2 / g, 60 m 2 / g, 70 m 2 / g, 80 m 2 / g, 90 m 2 / g, 100 m 2 / g, 110 m 2 / g, 120 m 2 / g, 130 m 2 / g, 140 m 2 / g, 150 m 2 / g, 160 m 2 / g, 170 m 2 / g, 180 m 2 / g or a range composed of any two of the above values.

[0028] In some embodiments, the specific capacity of the carbon black raw material is from 200 mAh / g to 310 mAh / g. In some embodiments, the specific capacity of the carbon black raw material is 200 mAh / g, 210 mAh / g, 220 mAh / g, 230 mAh / g, 240 mAh / g, 250 mAh / g, 260 mAh / g, 270 mAh / g, 280 mAh / g, 290 mAh / g, 300 mAh / g, 310 mAh / g or a range composed of any two of the above values.

[0029] In some embodiments, the mass ratio of the ball milling medium used in ball milling to the carbon black raw material is from 2 to 30. Within a certain range, the higher the mass ratio of the ball milling medium to the carbon black raw material, the higher the probability of collision between the carbon black raw material and the medium, and the higher the local temperature, resulting in more obvious changes in the structure of the carbon black raw material; however, if the mass ratio is too high, the local temperature is too high, which may cause damage to the structure of the carbon black raw material; if the mass ratio of the ball milling medium to the carbon black raw material is too low, the collision between the carbon black raw material and the medium is insufficient, and the local temperature is too low, and the surface of the carbon black raw material cannot be modified; limiting the mass ratio of the ball milling medium to the carbon black raw material within the above range can ensure that the surface of the carbon black is disordered and modified with oxygen functional groups without destroying the structure of the carbon black primary particles. Exemplarily, the mass ratio of the ball milling medium to the carbon black raw material is 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 or a range composed of any two of the above values. In some embodiments, the mass ratio of the ball milling medium to the carbon black raw material is from 10 to 30.

[0030] In some embodiments, the rotation speed of ball milling is from 600 rpm to 1500 rpm. If the rotation speed of ball milling is too high, the carbon black raw material collides with the medium too sufficiently, resulting in too high a local temperature, which may damage the structure of the carbon black raw material; if the rotation speed of ball milling is too low, the collision between the carbon black raw material and the medium is insufficient, and the local temperature is too low, and the surface of the carbon black raw material cannot be modified. Limiting the rotation speed of ball milling within the above range is beneficial to disordering the surface of the carbon black raw material and modifying the oxygen functional groups without damaging the primary particle structure of the carbon black raw material. Exemplarily, the rotation speed of ball milling is 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm or the range composed of any two of the above values. In some embodiments, the rotation speed of ball milling is from 900 rpm to 1400 rpm. In some embodiments, the rotation speed of ball milling is 900 rpm.

[0031] In some embodiments, the ball milling time is from 3 h to 12 h. In some embodiments, the ball milling time is 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h to 12 h or the range composed of any two of the above values. In some embodiments, the ball milling time is 9 h.

[0032] In some embodiments, the preparation method of the carbon black material specifically includes the following steps:

[0033] S1. Place the carbon black raw material in a ball milling tank, add a ball milling medium, and the mass ratio of the ball milling medium to the carbon black raw material is 2 to 30;

[0034] S2. Set the parameters of the ball milling tank: the rotation speed is from 600 rpm to 1500 rpm, and the ball milling time is from 3 h to 12 h, and perform ball milling;

[0035] S3. After the ball milling is completed, take out the ball milling medium to obtain the carbon black material.

[0036] In some embodiments, the ball milling tank is at least one of an agate ball milling tank, agate, corundum, tungsten carbide, nylon, and zirconia. In some embodiments, the ball milling tank is an agate ball milling tank.

[0037] In some embodiments, the material of the ball milling medium can be selected from at least one of agate, corundum, tungsten carbide, and zirconia. In some embodiments, the material of the ball milling medium is agate.

[0038] In some embodiments, the diameter of the ball milling medium is from 3 mm to 10 mm. Under the condition that the mass of the used ball milling medium is constant, the larger the diameter of the ball milling medium, the fewer the number, and the lower the probability of colliding with the carbon black raw material. In some embodiments, the diameter of the ball milling medium is 3 mm.

[0039] In some embodiments, the ball milling tank operates as follows: continuous ball milling for 30 minutes and then pausing for 10 minutes. If continuous ball milling is used, it may cause the temperature inside the ball milling tank to be too high.

[0040] Negative electrode sheet

[0041] One or more embodiments of the present application provide a negative electrode sheet, which includes a negative electrode active material layer, and the negative electrode active material layer includes the aforementioned carbon black material or the carbon black material prepared according to the aforementioned preparation method.

[0042] In some embodiments, the negative electrode active material layer further includes a negative electrode active material, and the negative electrode active material includes at least one of a silicon-based material, a carbon-based material, a tin-based material, a phosphorus-based material, and metallic lithium. Exemplarily, the silicon-based material includes at least one of silicon, a silicon alloy, a silicon oxide compound, and a silicon carbide compound. Exemplarily, the carbon-based material includes at least one of graphite, soft carbon, hard carbon, carbon nanotubes, and graphene. Exemplarily, the tin-based material includes at least one of tin, a tin oxide, and a tin alloy. Exemplarily, the phosphorus-based material includes at least one of phosphorus and a phosphorus complex.

[0043] In some embodiments, the negative electrode active material layer further includes a binder. The binder includes, but is not limited to: at least one of polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1,1-difluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, or nylon, etc.

[0044] In some embodiments, the negative electrode sheet further includes a negative electrode current collector, and the negative electrode current collector includes: at least one of a copper foil, a nickel foil, a stainless steel foil, a titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or any combination thereof.

[0045] Secondary battery

[0046] One or more embodiments of the present application provide a secondary battery, which includes the aforementioned negative electrode sheet.

[0047] In some embodiments, the secondary battery further includes a positive electrode sheet, an electrolyte, and a separator.

[0048] In some embodiments, the positive electrode sheet includes a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode active material.

[0049] In some embodiments, the positive electrode active material includes at least one of lithium iron phosphate-based materials, lithium cobaltate-based materials, and nickel-cobalt-based ternary materials. In some embodiments, the lithium iron phosphate-based materials include Li x Fe y R (1-y) PO4 materials, where R includes at least one of the elements Mn, Co, Ti, Mg, Ca, Cr, Cu, Ni, V, Mo, Zn, Al, B, and Nb, 0.05 ≤ x ≤ 1.2, 0 < y ≤ 1. In some embodiments, the lithium cobaltate-based materials include Li 1+z Co 1-j-k Ma j Mb k O2 materials, where Ma is at least one of Al, Ga, Hf, Mg, Sn, Zn, Zr; Mb is at least one of Ni, Mn, V, Mo, Nb, Cu, Fe, In, W, and Cr, 0 ≤ j ≤ 0.01, 0 ≤ k ≤ 0.01, -0.05 ≤ z ≤ 0.08. In some embodiments, the nickel-cobalt-based ternary materials include Li a Ni m Co n A (1 - m-n) O2 materials, where A includes at least one of Mn, Al, Mg, Cr, Ca, Zr, Mo, Ag, and Nb, 0.9 ≤ a ≤ 1.2, 0.5 ≤ m ≤ 1, 0 ≤ n ≤ 0.5, m + n ≤ 1.

[0050] In some embodiments, the positive electrode active material layer further includes a binder, and optionally includes a conductive material. The binder improves the binding between the positive electrode active material particles and also improves the binding between the positive electrode active material and the current collector.

[0051] In some embodiments, the binder includes, but is not limited to: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1,1-difluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, or nylon, etc.

[0052] In some embodiments, the conductive material includes, but is not limited to: carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof. In some embodiments, the carbon-based materials are selected from natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or any combination thereof. In some embodiments, the metal-based materials are selected from metal powder, metal fiber, copper, nickel, aluminum, or silver. In some embodiments, the conductive polymer is a polyphenylene derivative.

[0053] In some embodiments, the positive electrode further includes a positive electrode current collector, and the positive electrode current collector can be a metal foil or a composite current collector. For example, aluminum foil can be used. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer substrate.

[0054] In some embodiments, the electrolyte includes a lithium salt, and the lithium salt includes at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium trifluoromethanesulfonate (LiOTf), lithium bis(oxalato)borate (LiBOB), lithium bis(fluoromalonate)borate (LiBFMB), and lithium difluoro(oxalato)borate (LiDFOB). In some embodiments, the lithium salt is preferably LiPF6.

[0055] In some embodiments, the electrolyte further includes a non-aqueous solvent, and the non-aqueous solvent includes at least one of a chain carbonate compound, a cyclic carbonate compound, and a carboxylic acid ester compound.

[0056] In some embodiments, the chain carbonate compound includes, but is not limited to, one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), or methyl ethyl carbonate (MEC).

[0057] In some embodiments, the cyclic carbonate compound includes, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), or vinylene carbonate (VEC).

[0058] In some embodiments, the carboxylic acid ester compound includes, but is not limited to, one or more of methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolactone, decanolide, valerolactone, or caprolactone.

[0059] In some embodiments, a separator is provided between the positive electrode sheet and the negative electrode sheet to prevent short circuit. The material and shape of the separator that can be used in the embodiments of the present application are not particularly limited, and it can be any technology disclosed in the prior art. In some embodiments, the separator includes a polymer or an inorganic substance formed of a material stable to the electrolyte of the present application.

[0060] In some embodiments, the separator includes a base film and a coating provided on the base film. The base film includes at least one of a polyethylene film, a polypropylene film, a PP / PE / PP composite film, a polyimide film, an aramid film, a polyethylene terephthalate film, or a non-woven fabric. In some embodiments, the coating includes at least one of a polymer layer, an inorganic ceramic layer, or a mixed layer of a polymer and an inorganic ceramic layer.

[0061] In some embodiments, the inorganic ceramic layer includes inorganic particles and a binder. The inorganic particles include at least one of alumina, silica, magnesia, titania, hafnium dioxide, tin dioxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconia, yttria, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, or barium sulfate. The binder includes at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate salt, polyvinylpyrrolidone, polyethylene ether, polymethyl methacrylate, polytetrafluoroethylene, or polyhexafluoropropylene.

[0062] The polymer layer contains a polymer, and the material of the polymer includes at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate salt, polyvinylpyrrolidone, polyethylene ether, polyvinylidene fluoride, or poly(vinylidene fluoride - hexafluoropropylene).

[0063] In some embodiments, the secondary battery is a lithium secondary battery or a sodium secondary battery. In some embodiments, 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 polymer secondary battery.

[0064] In some embodiments, the lithium ion secondary battery may include an outer package, and the outer package can be a hard case, such as a hard plastic case, an aluminum case, a steel case, etc. The outer package of the lithium ion secondary battery can also be a soft package, such as a pouch - type soft package. The material of the soft package can be a plastic, such as one or several of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc.

[0065] In some embodiments, the shape of the lithium ion secondary battery is not particularly limited, and it can be cylindrical, square, or any other arbitrary shape.

[0066] Device

[0067] This application also provides a device, and the device includes the above - mentioned secondary battery.

[0068] In some embodiments, the device includes, but is not limited to: a laptop computer, a pen - input computer, a mobile computer, an e - book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head - mounted stereo headset, a video recorder, a liquid crystal TV, a portable cleaner, a portable CD player, a minidisc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a moped, a bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flash, a camera, a large household battery, or a lithium ion capacitor, etc.

[0069] Examples and Comparative Examples

[0070] The following are examples and comparative examples for further specific illustration of the present application. However, the present application is not limited to these examples as long as it does not deviate from its main idea.

[0071] The carbon black materials used in the following examples were prepared by the preparation method of the present application, and other materials such as carbon black raw materials and solvents were obtained commercially.

[0072] Preparation of Carbon Black Materials

[0073] Example 1

[0074] S1. Place 5 g of carbon black raw material with a specific surface area of 45 m 2 / g and a specific capacity of 221 mAh / g into a 200 mL agate ball mill pot, add 100 g of agate beads with a diameter of 3 mm, and the mass ratio of agate beads to carbon black raw material (ball-to-material mass ratio) is 20;

[0075] S2. Set the parameters of the agate ball mill pot: the rotation speed is 900 rpm, and the ball milling time is 9 h. Among them, for every continuous ball milling for 30 min, pause for 10 min and then continue ball milling;

[0076] S3. After the ball milling is completed, scrape the carbon black material from the agate ball mill pot. After taking out the agate beads, test the carbon black material. The test data are shown in Table 1 below.

[0077] Examples 2 - 10

[0078] Examples 2 - 10 are achieved by adjusting the specific surface area and specific capacity of the carbon black raw material, the ball-to-material mass ratio, the rotation speed of ball milling, the ball milling time, etc. on the basis of Example 1. The specific adjustment measures and test data are shown in Table 1. Other preparation methods are the same as those in Example 1.

[0079] Comparative Examples 1 - 4

[0080] Comparative Examples 1 - 4 are achieved by adjusting the specific surface area and specific capacity of the carbon black raw material, the ball-to-material mass ratio, the rotation speed of ball milling, the ball milling time, etc. on the basis of Example 1. The specific adjustment measures and test data are shown in Table 1. Other preparation methods are the same as those in Example 1.

[0081] 2. Preparation of CR2016 Type Lithium Ion Button Battery

[0082] Negative electrode sheet: Carbon black material (prepared in Examples 1-10 and Comparative Examples 1-4), thickener sodium carboxymethyl cellulose (CMCNa), and binder styrene-butadiene rubber (SBR) were mixed in a certain mass ratio, and deionized water was added to fully homogenize to prepare a negative electrode slurry. The mixed negative electrode slurry was coated on one side of a negative electrode current collector copper foil with a thickness of 6 μm, and after drying, it was rolled to obtain a negative electrode sheet, and punched into 14 mm discs to obtain a single-sided negative electrode sheet.

[0083] Positive electrode sheet: A metal lithium sheet with a diameter of 18 mm is used as the positive electrode sheet.

[0084] Electrolyte: LiPF6 was added to a solvent mixed with ethylene carbonate (EC), dimethyl carbonate (DMC) and diethyl carbonate (DEC) (weight ratio 1:1:1) and mixed evenly to obtain an electrolyte, in which the mass percentage of LiPF6 was 12.5%.

[0085] Separator membrane: Celgard 2400 polypropylene microporous membrane is used as the separator membrane.

[0086] Preparation of CR2016 lithium-ion button battery: move the positive electrode sheet (lithium sheet), separator, negative electrode sheet, electrolyte, battery shell and other accessories into a glove box filled with Ar gas (water content is less than 11ppm); assemble the battery in the stacking order from bottom to top and inject the electrolyte: positive electrode shell>flat pad+appropriate amount of electrolyte>metal lithium sheet+appropriate amount of electrolyte>a layer of separator+appropriate amount of electrolyte>negative electrode sheet+appropriate amount of electrolyte>flat pad+appropriate amount of electrolyte>spring>negative electrode shell; package on a packaging machine to obtain a button battery.

[0087] Test Method

[0088] 1. Particle specific surface area test

[0089] Refer to GB / T 10722—2003.

[0090] 2. Specific capacity test

[0091] The electrochemical performance of button cells was tested using a blue electric test cabinet. The specific test method is: discharge to 0.005V at 0.1C in the voltage range of 0.005V-1.5V at 25°C, let stand for 5 minutes, discharge to 0.005V at 0.05C, let stand for 5 minutes, and charge to 1.5V at 0.1C. This charge capacity is the measured capacity of the negative electrode. Four button cells were tested in parallel and the average value was taken.

[0092] 3. First Coulomb efficiency test

[0093] The electrochemical performance of the battery was tested using a Blue Electric test cabinet. The specific test method was as follows: at 25 °C, it was discharged to 0.005 V at 0.1 C within the voltage range of 0.005 V - 1.5 V, after standing for 5 min, it was discharged to 0.005 V at 0.05 C, and after standing for 5 min, it was charged to 1.5 V at 0.1 C. Among them, the charge-discharge efficiency = the first charging capacity / (0.1 C discharge specific capacity + 0.05 C discharge specific capacity) × 100%.

[0094] 4. X-ray Photoelectron Spectroscopy (XPS) Test

[0095] Sample preparation: 2 mg of the powder sample was adhered to double-sided carbon conductive adhesive or ordinary double-sided adhesive. The specific test conditions and steps were as follows: using monocrystalline spectral AlKα rays, placed at the X-ray point, using an elliptical form of 1000×1750 μm with an output of 10 KV and 22 mA, for neutral carbon C1s, 284.8 eV was used, and for data processing such as peak discrimination, 3-point smoothing, peak area measurement, background subtraction, and peak synthesis were used to calculate the atoms of each component.

[0096] 5. Raman Test

[0097] The sample was observed using a microscopic objective lens with a magnification of 50 times, and a laser with a wavelength of 532 nm was used for testing. The sample area was scanned for spectra, and 9 effective spectra were collected. The peak area values I D and I G of the D peak and G peak were obtained by Lorentzian line shape fitting, and the I D / I G of the 9 effective spectra was calculated, and the average value of the 9 numbers was taken.

[0098] Table 1

[0099]

[0100]

[0101] From the data comparison of Examples 1-10 and Comparative Examples 1-4 in Table 1, it can be seen that the carbon black materials of Examples 1-10 of the present application have a higher degree of defect compared with Comparative Examples 1-4, indicating that the carbon black materials have the characteristics of high surface disorder, have more active sites, can significantly improve their specific capacity and specific surface area, and while improving the degree of defect, specific surface area and oxygen functional group content of the carbon black materials of Examples 1-10 of the present application, it can also ensure that their initial Coulomb efficiency is the same as that of Comparative Examples 1-4. The possible reason is that in the present application, through the method of mechanical high-energy ball milling, the microcrystalline graphite layer of carbon black is disordered, the surface has a higher degree of defect, and at the same time, the carbon layer on the surface of carbon black reacts with oxygen in the air to form oxygen-containing functional groups, thereby increasing the active sites for lithium intercalation of carbon black. This carbon black material can not only form a conductive network to provide an electron transport path for the negative electrode material, but also contribute a higher specific capacity and energy density in the negative electrode sheet, ensuring the first-cycle Coulomb efficiency of the secondary battery.

[0102] Although some exemplary embodiments of the present application have been illustrated and described, the present application is not limited to the disclosed embodiments. On the contrary, those of ordinary skill in the art will recognize that some modifications and changes can be made to the described embodiments without departing from the spirit and scope of the present application as described in the appended claims.

Claims

1. A carbon black material, wherein the carbon black material satisfies: I D / I G is from 1.6 to 2.3, wherein, I D / I G refers to the peak area ratio of the D peak to the G peak of the carbon black material.

2. The carbon black material according to claim 1, wherein, The I of the carbon black material D / I G is 1.6 to 2.

1.

3. The carbon black material according to claim 1, wherein, The carbon black material satisfies at least one of the following conditions: (1) The specific capacity of the carbon black material is 310 mAh / g to 450 mAh / g; (2) The specific surface area of the carbon black material is 100 m 2 / g to 350 m 2 / g; (3) The carbon black material includes oxygen-containing functional groups, where the oxygen-containing functional groups include at least one of C-O, C=O, and O-C=O.

4. The carbon black material according to claim 3, wherein, The carbon black material satisfies at least one of the following conditions: (1) The specific capacity of the carbon black material is 320 mAh / g to 405 mAh / g; (2) The specific surface area of the carbon black material is 110 m 2 / g to 315 m 2 / g; (3) Based on the mass of the carbon black material, the mass percentage content of the oxygen-containing functional groups is 5% to 30%.

5. A method for preparing the carbon black material according to any one of claims 1 to 4, comprising: The step of obtaining the carbon black material by ball-milling carbon black raw materials.

6. The preparation method according to claim 5, wherein, The preparation method satisfies at least one of the following conditions: (1) The specific surface area of the carbon black raw material is 40 m 2 / g to 180 m 2 / g; (2) The specific capacity of the carbon black raw materials is 200 mAh / g to 310 mAh / g; (3) The mass ratio of the ball-milling medium used in the ball-milling to the carbon black raw materials is 2 to 30; (4) The rotation speed of the ball-milling is 600 rpm to 1500 rpm; (5) The time of the ball-milling is 3 h to 12 h.

7. A negative electrode plate, comprising a negative electrode active material layer, wherein the negative electrode active material layer comprises the carbon black material according to any one of claims 1 to 4 or the carbon black material prepared by the preparation method according to any one of claims 5 or 6.

8. A secondary battery, comprising a positive electrode plate, an electrolyte, a separator and the negative electrode plate according to claim 7.

9. A device, characterized in that, The device includes the secondary battery according to claim 8.

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