Negative electrode sheet, battery, and electric device

Abstract

The application provides a negative electrode sheet, a battery and an electric device. The negative electrode sheet comprises a current collector and a negative active material layer arranged on at least one side of the current collector; the negative active material layer comprises an active material and conductive carbon black; the active material comprises a carbon-based material; and the conductive carbon black satisfies: 0.3≤0.1 22 / [r 3 R 3 PSkρ 2 (OAN)]≤0.5. The negative electrode sheet provided by the application has the following effects because it contains the conductive carbon black required by the application: first, it has good electrolyte absorption capacity and liquid retention capacity, can enhance the electrolyte infiltration effect of the electrode sheet, improve the ionic conductivity of the negative electrode sheet, and improve the rate performance and high-temperature cycle performance of the battery; second, the conductive carbon black is more uniformly dispersed in the negative electrode sheet, can build a relatively complete conductive network structure, form a good electron-ion channel, improve the conductive capacity of the negative electrode sheet, and improve the rate performance of the battery; third, by selecting the conductive carbon black meeting the requirements of the application, the side reaction of the conductive carbon black interface with the electrolyte can be improved, and the initial efficiency and cycle life of the battery can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a negative electrode, a battery, and an electrical device. Background Technology

[0002] Lithium-ion batteries have seen rapid development in power tools, new energy vehicles, energy storage devices, and aerospace due to their advantages such as high energy density, high power density, long cycle life, and being green and pollution-free. The performance of lithium-ion batteries mainly depends on the positive and negative electrode materials, the separator, and the electrolyte, but the role of the conductive agent cannot be ignored.

[0003] Currently, the main function of conductive agents added to the negative electrode of lithium-ion batteries is to provide more overlap and buffering for the carbon-based negative electrode active material during the shrinkage / expansion process. Simultaneously, conductive agents can also improve the liquid absorption and retention capacity of the negative electrode. Carbon-based negative electrode active materials have good intrinsic conductivity, and conductive agents do not significantly improve the electronic conductivity of the negative electrode sheet; their main effect is to enhance ion transport performance. Therefore, conductive carbon black with high specific surface area, high porosity, and high liquid absorption is the preferred choice. However, conductive carbon black meeting these properties has a high surface energy, making it prone to agglomeration during slurry preparation. This leads to uneven distribution of conductive carbon black in the negative electrode sheet, thereby degrading the electrochemical performance of the lithium-ion battery. Furthermore, the numerous conductive active sites on the surface of this conductive carbon black make it susceptible to film-forming reactions and other side reactions with the electrolyte, affecting the battery's initial efficiency and cycle life.

[0004] Therefore, it is particularly important to provide a suitable conductive carbon black for negative electrodes that balances the relationship between its conductivity, liquid absorption, dispersibility and conductive active sites to improve the electrochemical performance of lithium-ion batteries. Summary of the Invention

[0005] In view of this, this application provides a negative electrode sheet, which, by using a suitable conductive carbon black, enables the battery to maintain excellent electrochemical performance.

[0006] A first aspect of this application provides a negative electrode sheet, the negative electrode sheet comprising a current collector and a negative electrode active material layer disposed on at least one side of the current collector; the negative electrode active material layer comprises a negative electrode active material and a conductive agent; the negative electrode active material comprises a carbon-based material; the conductive agent comprises conductive carbon black; the conductive carbon black satisfies: 0.3 ≤ 0.1 22 / [r 3 R 3 PSkρ 2 [(OAN)]≤0.5, where r is the primary particle size of the conductive carbon black, in cm; R is the particle size (D) corresponding to a cumulative volume fraction of 50% for the conductive carbon black. V50P is the pore volume of the conductive carbon black, in mL / g; S is the specific surface area of ​​the conductive carbon black, in m². 2 / g; ρ is the compacted density of the conductive carbon black powder, in g / cm³. 3 OAN is the oil absorption value of the conductive carbon black, in mL / 100g; k is a constant value of 17.5.

[0007] The negative electrode sheet provided in this application, containing the conductive carbon black required by this application, has the following effects: First, it has good electrolyte absorption and retention capabilities, which can enhance the electrolyte wetting effect of the electrode sheet, improve the ionic conductivity of the negative electrode sheet, and improve the rate performance and high-temperature cycle performance of the battery; Second, the conductive carbon black is more uniformly dispersed in the negative electrode sheet, which can build a more complete conductive network structure, form good electron-ion channels, improve the conductivity of the negative electrode sheet, and improve the rate performance of the battery; Third, by selecting conductive carbon black that meets the requirements of this application, the side reactions between the conductive carbon black interface and the electrolyte can also be improved, thereby improving the battery's initial efficiency and cycle life.

[0008] A second aspect of this application provides a battery including the negative electrode provided in the first aspect of this application.

[0009] Since the battery includes the negative electrode provided in the first aspect of this application, the battery has high initial efficiency and capacity, good rate performance and cycle life, and meets more application requirements.

[0010] A third aspect of this application provides an electrical device, including the battery provided in the second aspect of this application. Attached Figure Description

[0011] The accompanying drawings are provided to further understand the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof.

[0012] Figure 1 This is a SEM image of the conductive carbon black in Example 1 of this disclosure. Detailed Implementation

[0013] The present application is further illustrated below with examples and comparative examples. These examples are merely illustrative and the present application is not limited to these examples. Any modifications or equivalent substitutions to the technical solutions of the present application that do not depart from the scope of the technical solutions of the present application should be covered within the protection scope of the present application.

[0014] Lithium-ion batteries have seen rapid development in power tools, new energy vehicles, energy storage devices, and aerospace due to their advantages such as high energy density, high power density, long cycle life, and being green and pollution-free. The performance of lithium-ion batteries mainly depends on the positive and negative electrode materials, the separator, and the electrolyte, but the role of the conductive agent cannot be ignored.

[0015] Currently, the main function of conductive agents added to the negative electrode of lithium-ion batteries is to provide more overlap and buffering for the carbon-based negative electrode active material during the shrinkage / expansion process. Simultaneously, conductive agents can also improve the liquid absorption and retention capacity of the negative electrode. Carbon-based negative electrode active materials have good intrinsic conductivity, and conductive agents do not significantly improve the electronic conductivity of the negative electrode sheet; their main effect is to enhance ion transport performance. Therefore, conductive carbon black with high specific surface area, high porosity, and high liquid absorption is the preferred choice. However, conductive carbon black meeting these properties has a high surface energy, making it prone to agglomeration during slurry preparation. This leads to uneven distribution of conductive carbon black in the negative electrode sheet, thereby degrading the electrochemical performance of the lithium-ion battery. Furthermore, the numerous conductive active sites on the surface of this conductive carbon black make it susceptible to film-forming reactions and other side reactions with the electrolyte, affecting the battery's initial efficiency and cycle life.

[0016] The first embodiment of this application provides a negative electrode sheet, which includes a current collector and a negative electrode active material layer disposed on at least one side of the current collector; the negative electrode active material layer includes an active material and a conductive agent; the active material includes a carbon-based material; the conductive agent includes conductive carbon black; the conductive carbon black satisfies: 0.3 ≤ 0.1 22 / [r 3 R 3 PSkρ 2 [(OAN)]≤0.5, where r is the primary particle size of conductive carbon black in cm; R is the particle size (D) corresponding to a cumulative volume fraction of conductive carbon black of 50%. V50 ), where P is the pore volume of conductive carbon black, in mL / g; and S is the specific surface area of ​​conductive carbon black, in m². 2 / g; ρ is the compacted density of conductive carbon black powder, in g / cm³. 3 OAN is the oil absorption value of conductive carbon black, in mL / 100g; k is a constant, 17.5.

[0017] The negative electrode provided in this application, containing the conductive carbon black required by this application, has the following effects: First, it possesses excellent electrolyte absorption and retention capabilities, enhancing the electrolyte wetting effect of the electrode, improving the ionic conductivity of the negative electrode, and increasing the rate performance and high-temperature cycle performance of the battery; Second, the conductive carbon black is more uniformly dispersed in the negative electrode, enabling the construction of a more complete conductive network structure, forming good electron-ion channels, improving the conductivity of the negative electrode, and increasing the rate performance of the battery; Third, by selecting conductive carbon black that meets the requirements of this application, the side reactions between the conductive carbon black interface and the electrolyte can also be improved, enhancing the battery's initial efficiency and cycle life. When the concentration is less than 0.3 or greater than 0.5, the overall performance of the battery will be affected.

[0018] Among them, the primary particle size (r) of conductive carbon black is related to the intrinsic conductivity of conductive carbon black, affecting the overall specific surface area and the number of conductive carbon black particles per unit mass. It has a significant impact on the formation of conductive channels and conductive networks. Suitable primary particles can improve the stability of the slurry and help build the conductive network, increasing the contact points with the negative electrode active material, thereby improving battery performance; the D corresponding to a volume fraction of 50% V50 The appropriate D affects the construction of the conductive network in conductive carbon black and the porosity of the negative electrode. V50 The conductivity of conductive carbon black is beneficial for filling the spaces between the negative electrode active materials, forming a better conductive network, increasing electron transport and ion diffusion rates, and thus improving battery performance. The pore volume (P) of conductive carbon black affects its specific surface area and the porosity of the negative electrode sheet. A suitable pore volume can improve the stability of the slurry and the negative electrode sheet, and can create more ion transport channels in the negative electrode sheet, thereby improving battery performance. The specific surface area (S) of conductive carbon black directly affects its intrinsic conductivity. A suitable conductive carbon black can improve the stability of the slurry and build a good conductive network, thereby improving battery performance. The oil absorption value (OAN) of conductive carbon black affects the liquid absorption and retention of the negative electrode sheet. A suitable oil absorption value can provide more liquid retention for the negative electrode sheet without affecting the slurry, improving the battery's cycle and low-temperature performance. The compaction density (ρ) of conductive carbon black affects the contact tightness between the conductive carbon black and the negative electrode active material in the negative electrode sheet. A suitable compaction density helps to improve the overall conductivity of the negative electrode sheet, reduce resistance, and thus affect the battery's continuous charge and discharge performance. The inventors of this application, through experimental research, discovered a reasonable balance between the various parameters of conductive carbon black, ensuring that 0.3 ≤ 0.1. 22 / [r 3 R 3 PSkρ 2 When the (OAN) value is ≤0.5, a negative electrode and battery with superior capacity, rate capability, cycle life, and initial charge / discharge performance will be obtained. When it is less than 0.3 or greater than 0.5, the overall performance of the battery will be affected.

[0019] The oil absorption value (OAN) of conductive carbon black is tested according to the national standard GB / T3780.2-2003. Specifically, the test oil (dibutyl phthalate, linseed oil, or paraffin oil) is added dropwise to a certain amount of sample (conductive carbon black). The mixture is stirred and rolled with a glass rod until it changes from a free-flowing powder to a semi-plastic substance. The endpoint is reached when all the conductive carbon black is rolled onto the glass rod and no oil stains appear on the glass plate. The oil absorption value (mL / 100g) of conductive carbon black is calculated. Each sample is tested 3 times and the average value is taken.

[0020] The specific surface area (S) and pore volume (P) of conductive carbon black were tested using a Micromeritics specific surface area analyzer according to the national standard GB / T19587.

[0021] The particle size (D) corresponding to a cumulative volume fraction of conductive carbon black of 50%. V50 The particle size was tested using a Mastersizer 3000 laser particle size analyzer according to the national standard GB / T24533-2019.

[0022] The primary particle size (r) of conductive carbon black was obtained by scanning electron microscopy to statistically analyze the average diameter of 100 randomly selected particles per unit area.

[0023] The compacted density (ρ) of conductive carbon black powder was obtained by measuring the powder compaction at a pressure of 200 MPa using a powder compaction resistance meter. k is a constant, 17.5.

[0024] In this application, the conductive carbon black further satisfies: 0.35 ≤ 0.1 22 / [r 3 R 3 PSkρ 2 [OAN]≤0.45. Parameters of conductive carbon black.

[0025] Meeting the above ranges will result in negative electrode sheets and batteries with better capacity, rate capability, cycle life, and first charge point efficiency.

[0026] In this application, the primary particle size r of the conductive carbon black satisfies 0.0000029 cm ≤ r ≤ 0.000034 cm. A primary particle size within this range improves the stability of the slurry and facilitates the construction of the conductive network, increasing the contact points with the negative electrode active material.

[0027] In this application, the D of conductive carbon black V50 Satisfying 0.00043m≤D V50 ≤0.0005cm. D of conductive carbon black. V50 Within the aforementioned range, it is beneficial for conductive carbon black to fill between negative electrode active materials, forming a better conductive network and increasing electron transport and ion diffusion rates.

[0028] In this application, the pore volume P of the conductive carbon black satisfies: 0.15 mL / g ≤ P ≤ 0.30 mL / g. A pore volume within this range improves the stability of the slurry and reduces side reactions between the conductive carbon black and the electrolyte. Furthermore, it provides suitable porosity in the negative electrode sheet, ensuring optimal lithium-ion transport.

[0029] In this application, the specific surface area S of the conductive carbon black satisfies: 50m² 2 / g≤S≤80m 2 / g. A specific surface area of ​​conductive carbon black within the above range is beneficial for carbon black dispersion and reduces side reactions between conductive carbon black and the electrolyte. This allows for the construction of a good conductive network, thereby increasing the electron conduction and ion transport rates in the negative electrode.

[0030] In this application, the oil absorption value (OAN) of the conductive carbon black satisfies the following condition: 200 mL / 100 g ≤ OAN ≤ 280 mL / 100 g. An oil absorption value within this range is beneficial for increasing the absorption of electrolyte by the negative electrode, thereby increasing the ion transport rate.

[0031] In this application, the compacted density ρ of the conductive carbon black powder satisfies: 0.90 g / cm³. 3 ≤ρ≤1.20g / cm 3 When the compacted density of conductive carbon black powder is within the above range, it helps to improve the overall conductivity of the negative electrode and reduce resistance.

[0032] In this application, the conductive agent also includes one or more of graphene, carbon nanotubes, or carbon nanofibers. The conductive carbon black can form point-to-surface, point-to-line, or point-to-line-to-surface contact modes with any of the graphene, carbon nanotubes, or carbon nanofibers, further constructing the electron-ion conductive network of the negative electrode.

[0033] In this application, the conductive carbon black can be one or more of acetylene black, furnace black, tank black, pyrolysis black, lamp black, and Ketjen black. Conductive carbon black is a zero-dimensional material with a superior geometric configuration. It can form a buffer structure with point contact between the negative electrode active materials, uniformly dispersing the stress changes caused by expansion and contraction during the charging and discharging process of the negative electrode active materials, preventing electrical connection interruptions due to electrode cracking, and thus forming a long-range ordered conductive network. Moreover, conductive carbon black is a relatively mature conductive agent for lithium-ion batteries. By optimizing the conductive carbon black to meet the above parameter range, the conductivity and liquid absorption and retention capacity of the negative electrode can be enhanced. This is a development method for negative electrodes and batteries that can reduce costs and increase efficiency.

[0034] In this application, the negative electrode active material also includes one or more of silicon-based materials, tin-based materials, and lithium titanate materials. The above negative electrode materials, when used in combination with carbon-based materials in appropriate proportions, can meet the needs of different lithium-ion battery applications. The silicon-based material can be elemental silicon or silicon oxide (SiO₂). x Tin-based materials can be elemental tin, tin oxide (SnO), or a combination of one or more of the following: 0 < x < 2, silicon alloys, etc. x One or more combinations of 0 < x ≤ 2 and tin alloys. Lithium titanate material can be Li4Ti5O 12 wait.

[0035] In this application, carbon-based materials include one or more of artificial graphite, natural graphite, hard carbon materials, or soft carbon materials.

[0036] In this application, the negative electrode active material layer also includes a binder, which includes one or a combination of several of the following: styrene-butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyacrylic ethylene acrylic acid (PEAA), sodium alginate, carboxymethyl chitosan, polyacrylonitrile (PAN), and polyvinyl alcohol (PVA).

[0037] In this application, the current collector can be any one of copper foil, carbon-coated copper foil, polymer-coated copper foil, carbon cloth, carbon nanotube film, or carbon paper.

[0038] In this application, the mass percentage of conductive carbon black in the negative electrode active material layer is 0.1% to 3%. When the conductive carbon black content is within this range, the battery exhibits superior electrochemical performance.

[0039] In this application, the carbon-based material accounts for 80-96% of the mass of the negative electrode active material layer. Within this range, the carbon-based material can balance the battery's capacity and rate capability.

[0040] Accordingly, a second embodiment of this application provides a battery that includes the negative electrode provided in the first embodiment of this application. Because the battery includes the negative electrode provided in the first embodiment of this application, it has higher capacity, rate capability, cycle life, and initial charge / discharge efficiency, meeting a wider range of application requirements.

[0041] In this application, the battery may be a lithium-ion battery, and the lithium-ion battery may also include a positive electrode, a diaphragm, and an electrolyte.

[0042] In this application, the positive electrode sheet includes a current collector and a positive electrode active material layer coated on at least one side of the current collector; the positive electrode active material layer includes a positive electrode active material, a conductive agent, and a binder.

[0043] In this application, the positive electrode active material layer can be coated on one side of the current collector or on both sides of the current collector. When the positive electrode active material layer is coated on both sides of the current collector, the thickness, areal density, component content, etc. of the positive electrode active material layer located on both sides of the current collector can be designed independently according to the application requirements. They can be the same or different.

[0044] In this application, the positive current collector can be any one of aluminum foil, carbon-coated aluminum foil, polymer-coated aluminum foil, carbon cloth, carbon nanotube film, or carbon paper.

[0045] In this application, the diaphragm can be a composite membrane of one or more of polyethylene, polypropylene, and polyvinylidene fluoride.

[0046] In this application, the positive electrode active material can be one or a combination of several of the following: lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium phosphates with an olivine structure.

[0047] In this application, the electrolyte is an organic solvent in which charge carrier ions (lithium ions) are dissolved. This application does not impose any restrictions on the electrolyte; it can be formulated according to actual conditions.

[0048] The third embodiment of this application provides an electrical device. Using the battery provided in the second embodiment of this application, this electrical device can have higher market competitiveness.

[0049] In some embodiments of this application, the aforementioned electrical equipment includes, but is not limited to, mobile phones, laptops, tablets, smartwatches and other wearable electronic devices, e-cigarettes, as well as new energy vehicles, electric bicycles, etc.

[0050] The following detailed description of this application is based on specific experiments. By preparing a 1.7Ah stacked battery, the battery's first efficiency, discharge capacity, low-temperature DCIR (characterizing the battery's rate performance), and high-temperature cycle life were tested to illustrate the effectiveness of this scheme.

[0051] Example 1

[0052] The positive electrode active material lithium iron phosphate (LiFePO4), conductive carbon black, and binder PVDF are mixed in a ratio of 97:1:2. The powder and NMP are then stirred in a homogenizer to form a positive electrode slurry, which is then uniformly coated onto aluminum foil.

[0053] The negative electrode active material, artificial graphite, conductive carbon black, thickener (CMC), and binder (SBR) were mixed in a ratio of 96:1:1:2, wherein the conductive carbon black content was 0.1%. 22 / [r 3 R 3 PSkρ 2 [(OAN)] = 0.30. The powder and deionized water are mixed into a negative electrode slurry using a homogenizer and then uniformly coated onto copper foil to obtain a negative electrode sheet.

[0054] Ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 1:1:1 to prepare an electrolyte containing 1 M LiPF6.

[0055] Polypropylene separators were used to prepare 1.7Ah stacked cells, and their first efficiency, battery discharge capacity, low-temperature DCIR, and high-temperature cycle life were tested.

[0056] The difference between Examples 2-10, Comparative Examples 1-3, and the Examples lies in the optimized selection of conductive carbon black in the negative electrode sheet. Specific optimization parameters are shown in Table 1. Among them, the difference between Example 10 and Example 1 is that 0.3% carbon nanotubes were added during the negative electrode slurry preparation process.

[0057] Table 1. Characteristics of Conductive Agent Parameters

[0058]

[0059] Electrochemical performance testing:

[0060] The batteries prepared in the above embodiments and comparative examples were tested using the Blue Electric CT3002A battery testing system. The test results are summarized in Table 2.

[0061] Battery discharge capacity test: The battery was subjected to a 0.2C / 0.2C cycle test at 25℃, with a voltage range of 2.5V-4.2V (charged at 0.2C to 4.2V, rested for 30 minutes, and then discharged at 0.2C to 2.5V, which is one cycle). The cycle was repeated 3 times, and the discharge capacity of the battery on the third cycle was recorded as the discharge capacity (Ah) of the battery.

[0062] First charge / discharge test:

[0063] The battery was subjected to a 0.2C / 0.2C cycle test at 25℃, with a voltage range of 2.5V-4.2V (charged at 0.2C to 4.2V, rested for 30 minutes, and then discharged at 0.2C to 2.5V, which constitutes one cycle). The initial charge specific capacity and initial discharge specific capacity of the battery were recorded, and the initial charge-discharge efficiency of the battery was calculated based on these values. The initial discharge efficiency (%) of the battery = initial charge specific capacity / initial discharge specific capacity * 100%.

[0064] Low temperature -10℃ DCIR test:

[0065] Charge the battery at 0.2C to 4.2V at 25℃, let it rest for 30 minutes, and then discharge it at 0.2C to 2.5V. Repeat this cycle 3 times and take the charge and discharge data of the third cycle as the battery capacity. Then charge it at 0.2C to 50% SOC. Place the battery at -10℃ and charge it at 0.2C and 0.5C for 30 seconds respectively. Record the termination voltage and termination current of each process and calculate the DCIR of each process.

[0066] Cycle life test: Charge the battery at 1C to 4.2V at 45℃, let it rest for 10 minutes, and then discharge it at 1C to 2.5V. Repeat this cycle 500 times and record the capacity retention rate. The capacity retention rate (%) after 500 cycles = discharge specific capacity after 500 cycles / discharge specific capacity after the 3rd cycle * 100%.

[0067] Table 2 Electrochemical Performance Tests

[0068]

[0069] As can be seen from the data in Table 2, conductive carbon black was added to the negative electrode sheet provided in this application embodiment. The morphology of the conductive carbon black is as follows: Figure 1 As shown, conductive carbon black satisfies the formula 0.3 ≤ 0.1. 22 / [r 3 R 3 PSkρ 2 With (OAN)]≤0.5, the battery performance, discharge capacity, cycle performance, and low-temperature DCIR are improved compared to the control group.

[0070] The above description is an exemplary embodiment of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. A negative electrode, wherein, The negative electrode includes: A current collector and a negative electrode active material layer disposed on at least one side of the current collector; The negative electrode active material layer includes a negative electrode active material and a conductive agent; The negative electrode active material includes a carbon-based material; the conductive agent includes conductive carbon black. The conductive carbon black satisfies: , Where r is the primary particle size of the conductive carbon black, in cm; R is the particle size (D) corresponding to a cumulative volume fraction of 50% for the conductive carbon black. V50 P is the pore volume of the conductive carbon black, in mL / g; S is the specific surface area of ​​the conductive carbon black, in m². 2 / g; ρ is the compacted density of the conductive carbon black powder, in g / cm³. 3 OAN is the oil absorption value of the conductive carbon black, in mL / 100g; k is a constant value of 17.5; the conductive agent is one or more of acetylene black, furnace black, channel black, pyrolysis black, lamp black, and Ketjen black. The carbon-based material accounts for 80-96% of the mass of the negative electrode active material layer.

2. The negative electrode sheet according to claim 1, wherein, The conductive carbon black further satisfies: .

3. The negative electrode sheet according to claim 1, wherein, The conductive carbon black must satisfy at least one of the following conditions: The primary particle size r of the conductive carbon black satisfies: 0.0000029 cm ≤ r ≤ 0.000034 cm; The conductive carbon black has D V50 Satisfies: 0.00043 cm ≤ D V50 ≤0.0005 cm; The pore volume P of the conductive carbon black satisfies: 0.15 mL / g ≤ P ≤ 0.30 mL / g; The specific surface area S of the conductive carbon black satisfies: 50 m² 2 / g≤S≤80 m 2 / g; The oil absorption value OAN of the conductive carbon black satisfies: 200 mL / 100g ≤ OAN ≤ 280 mL / 100g; The compacted density ρ of the conductive carbon black powder satisfies: 0.90 g / cm³ 3 ≤ρ≤1.20 g / cm 3 .

4. The negative electrode sheet according to claim 1, wherein, The conductive agent also includes one or more of graphene, carbon nanotubes, or carbon nanofibers.

5. The negative electrode sheet according to claim 1, wherein, The negative electrode active material also includes one or more of silicon-based materials, tin-based materials, and lithium titanate materials.

6. The negative electrode according to claim 1, wherein, The carbon-based material includes one or more of artificial graphite, natural graphite, hard carbon materials, or soft carbon materials.

7. The negative electrode according to claim 1, wherein, The conductive carbon black accounts for 0.1% to 3% of the mass of the negative electrode active material layer.

8. A battery, wherein, Includes the negative electrode sheet as described in any one of claims 1 to 7.

9. An electrical appliance, wherein, Includes the battery as described in claim 8.

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