A lithium-ion battery

Abstract

The application provides a lithium ion battery, which comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprises a positive electrode current collector, a positive electrode active material layer and a safety coating layer arranged between the positive electrode current collector and the positive electrode active material layer, and the negative electrode sheet comprises a negative electrode current collector, a negative electrode active material layer arranged on the surface of the negative electrode current collector and a prelithiation material; the safety coating layer is a lithium-free phosphate, which is lithiated by the prelithiation material of the negative electrode during formation and circulation; under the condition that the system ratio is reasonable, the safety of the battery can be improved, the cost of the battery can be reduced and the energy density can be improved; the prelithiation material of the negative electrode can supplement the active lithium ions consumed by the SEI film and the CEI film generated by the positive electrode and the negative electrode when the phosphate material in the safety coating layer of the positive electrode is lithiated, so that the energy density of the battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology and relates to a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries, due to their advantages such as high energy density, high operating voltage, and no memory effect, are now widely used in everyday portable electronic products, power batteries, and energy storage systems. However, lithium-ion batteries are prone to safety accidents due to thermal runaway and other reasons. Currently, methods are being used to improve the safety performance of lithium-ion batteries, such as employing flame-retardant electrolytes, flame-retardant separators, solid electrolytes, coating active materials with flame-retardant substances, and applying safety coatings to the electrodes. However, a solution is needed that ensures safety without compromising the electrochemical performance of lithium-ion batteries to address their safety concerns.

[0003] The safety coating is located between the current collector and the electrochemical active material layer, making electrolyte wetting difficult. Furthermore, the active material content in the safety coating is relatively low, and some active material particles are tightly encapsulated by binders and conductive agents. These factors make lithium ion insertion and extraction difficult within the active material of the coating. Lithium ions that cannot be inserted or extracted cannot provide both capacity and mass. Moreover, the main cost of the active material in the safety coating comes from lithium ions, resulting in a waste of lithium resources.

[0004] CN109755465A discloses an electrode sheet, an electrochemical device, and a safety coating. The electrode sheet includes a current collector, an electrode active material layer, and a safety coating disposed between the current collector and the electrode active material layer. The safety coating comprises a polyvinylidene fluoride and / or polyvinylidene chloride polymer matrix, a conductive material, and an inorganic filler. The active material in the coating has difficulty in lithium ion insertion and extraction; lithium ions that cannot be inserted and extracted cannot provide both capacity and mass. Furthermore, the main cost of the active material in the safety coating comes from lithium ions, resulting in a waste of lithium resources.

[0005] CN103059613A discloses a safety coating for lithium-ion batteries. The materials used in the safety coating are one or a mixture of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates. The disclosed safety coating has the functions of absorbing heat upon thermal decomposition, changing the crystal structure, or pulverizing and releasing water or carbon dioxide. It can reduce the battery temperature when the battery is overheated. However, the safety coating increases the battery impedance at room temperature, resulting in poor rate performance. Summary of the Invention

[0006] The purpose of this invention is to provide a lithium-ion battery. This invention incorporates a safety coating in the positive electrode and a pre-lithiation material in the negative electrode. The safety coating is a lithium-free phosphate that is lithiated by the pre-lithiation material of the negative electrode during formation and cycling. With a reasonable system ratio, this design not only improves battery safety but also reduces battery cost and increases energy density. Furthermore, the negative electrode pre-lithiation material, while lithiating the phosphate material in the positive electrode safety coating, also replenishes the active lithium ions consumed in the formation of the SEI and CEI films at both the positive and negative electrodes, thereby increasing the battery's energy density.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a lithium-ion battery, the lithium-ion battery comprising a positive electrode and a negative electrode, the positive electrode comprising a positive current collector, a positive active material layer and a safety coating disposed between the positive current collector and the positive active material layer, and the negative electrode comprising a negative current collector, a negative active material layer disposed on the surface of the negative current collector and a pre-lithiation material.

[0009] In the lithium-ion battery of the present invention, the safety coating includes phosphate. Lithium ions released during the discharge process of the pre-lithiated material at the negative electrode can lithium-lithiate the phosphate in the safety coating that provides capacity, converting it to LiFe. 1-x-y Mn x M y Electrochemically active materials such as PO4. Active materials with sites that cannot utilize capacity will not be lithiated. Through system optimization, the lithium ions released by the lithium replenishment material are precisely matched with the lithiated safety coating active material, which can reduce the quality of the safety coating and thus the battery quality. Since phosphates that cannot utilize capacity will not be lithiated, and the pre-lithiated material at the negative end has a high decomposition rate, and lithium is the most expensive element in lithium-ion batteries, system optimization to ensure that the lithium ions released by the lithium replenishment material are precisely matched with the lithiated safety coating active material can reduce the cost of new battery structures.

[0010] Preferably, the pre-lithiation material is disposed inside the negative electrode active material layer, between the negative electrode active material layer and the negative electrode current collector, or on the surface away from the negative electrode current collector.

[0011] Preferably, the positive electrode active material layer, the safety coating, the negative electrode active material layer, and the pre-lithiation material all include a binder and a conductive agent.

[0012] Preferably, the adhesive comprises any one or a combination of at least two of polyvinylidene fluoride, modified polyvinylidene fluoride, polyvinylidene chloride, modified polyvinylidene chloride, polyvinylidene fluoride copolymer, polyvinylidene chloride copolymer, polymethyl methacrylate or styrene-butadiene rubber.

[0013] Preferably, the conductive agent includes any one or a combination of at least two of conductive carbon black, acetylene black, graphite, graphene, carbon nanotubes or carbon nanofibers.

[0014] Preferably, the positive electrode active material layer includes a positive electrode active material.

[0015] Preferably, the positive electrode active material includes any one or a combination of at least two of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese aluminum oxide, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, or lithium manganese silicate.

[0016] Preferably, the safety coating comprises inorganic fillers.

[0017] Preferably, the inorganic filler comprises a phosphate material.

[0018] Preferably, the chemical formula of the phosphate material is Fe. 1-x-y Mn x M y PO4, wherein 0≤x≤1, 0≤y≤0.1, 0≤x+y≤1, and M includes any one or at least two combinations of Sn, Cr, Mg, Ti, Al, Zn, W, Nb, or Zr.

[0019] Preferably, the negative electrode active material layer comprises a negative electrode active material.

[0020] Preferably, the negative electrode active material includes any one or a combination of at least two of graphite materials, silicon materials, silicon-carbon materials, or lithium titanate.

[0021] Preferably, the graphite material includes any one or a combination of at least two of the following: artificial graphite, natural graphite, hard carbon, soft carbon, or mesophase carbon microspheres.

[0022] Preferably, the pre-lithiation material comprises inert lithium powder and / or lithium foil.

[0023] It should be noted that when the pre-lithiation material described in this application is added to the negative electrode active material layer in a mixing manner, it does not include binders and conductive agents. The pre-lithiation material includes binders and conductive agents only when it is disposed as a pre-lithiation material layer on the surface of the negative electrode active material layer away from the current collector or between the negative electrode active material layer and the current collector.

[0024] The thickness of the safety coating is 0.05 to 30 μm, for example: 1 μm, 2 μm, 5 μm, 10 μm or 20 μm, preferably 1 to 6 μm.

[0025] Preferably, based on the mass of the safety coating as 100%, the mass percentage of the inorganic filler is 20% to 95%, for example: 20%, 25%, 50%, 80% or 95%, etc., preferably 60% to 85%.

[0026] Preferably, the adhesive accounts for 5% to 65% of the total mass, for example: 5%, 10%, 20%, 30%, or 65%.

[0027] Preferably, the conductive agent has a mass percentage of 5% to 25%, for example: 5%, 10%, 15%, 20% or 25%, etc.

[0028] Preferably, the particle size of the inorganic filler is 0.02 to 100 μm, for example: 0.02 μm, 0.1 μm, 0.5 μm, 1 μm, 10 μm or 100 μm, etc., and preferably 0.1 to 1 μm.

[0029] Preferably, the capacity C1 of the pre-lithiation material, the capacity C2 of the inorganic filler in the safety coating, the capacity C3 of the active material in the positive electrode active material layer, and the first-efficiency of the positive electrode - the first-efficiency of the negative electrode = η satisfy the relationship C1 = λ*C2 + C3*η, where 0.5 ≤ λ ≤ 1, and η < 0 is taken as 0.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention sets a safety coating in the positive electrode and a pre-lithiation material in the negative electrode. The safety coating is a lithium-free phosphate. During the formation and cycling process, it is lithiated by the pre-lithiation material of the negative electrode. Under reasonable system ratio, it can not only improve battery safety, but also reduce battery cost and increase energy density. While the pre-lithiation material of the negative electrode lithiates the phosphate material in the positive electrode safety coating, it can also replenish the active lithium ions consumed by the positive and negative electrodes in the formation of SEI film and CEI film, thereby improving battery energy density.

[0032] (2) The lithium-ion battery described in this invention can pass the needle penetration and compression tests 100% of the time, with a cycle life of up to 534 cycles and a capacity of up to 4890mAh. Attached Figure Description

[0033] Figure 1 This is a side view of a single-sided positive electrode sheet of the lithium-ion battery described in Example 1, where 1-positive electrode current collector, 2-safety coating, and 3-positive electrode active material layer.

[0034] Figure 2 This is a side view of the single-sided negative electrode sheet of the lithium-ion battery described in Example 1, 4-negative electrode current collector, 5-negative electrode active material layer, 6-pre-lithiation material.

[0035] Figure 3This is a side view of a single-sided negative electrode sheet of the lithium-ion battery described in Example 2, 4-negative electrode current collector, 5-negative electrode active material layer, 7-pre-lithiation material added to the negative electrode active material layer by mixing. Detailed Implementation

[0036] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0037] In the embodiments and comparative examples of this invention, the lithium-ion batteries were all prepared by the following method:

[0038] 1.1 Preparation of safety coating

[0039] A certain proportion of binder material, conductive agent material and inorganic filler are dispersed in N-methyl-2-pyrrolidone (NMP), stirred evenly, and then coated on the positive electrode current collector. After drying, a safety coating is obtained.

[0040] 1.2 Preparation of positive electrode with safety coating

[0041] Positive electrode sheet: 95% lithium cobalt oxide, 2% PVDF, 3% SP, and NMP are used as solvents. After stirring evenly, the mixture is coated on the safety coating on the surface of the positive current collector aluminum foil prepared by the method described in 1.1. After baking at 85°C, the positive electrode sheet is obtained by rolling, slitting, and baking at 85°C for 4 hours, followed by welding of electrode tabs and application of adhesive.

[0042] 1.3 Preparation of negative electrode with pre-lithiation material

[0043] Inert lithium powder + graphite negative electrode sheet: Inert lithium powder, active material graphite, conductive agent, binder and thickener are mixed in a certain proportion (where the active material graphite, conductive agent, binder and thickener are in a mass ratio of 96.5:1.0:1.5:1.0, and the amount of inert lithium powder added is calculated according to C1=λ*C2+C3*η). After being mixed evenly in NMP, the resulting slurry is coated on the negative electrode current collector copper foil, baked at 87℃, rolled and slit, and then baked at 80℃ for 12h before being soldered with tabs to form a negative electrode sheet.

[0044] Lithium foil + graphite: Active material graphite, conductive agent, binder and thickener are mixed in a mass ratio of 96.5:1.0:1.5:1.0. After being mixed evenly with deionized water, the resulting slurry is coated onto the negative electrode current collector copper foil. After baking at 87°C, it is rolled, slit, and then baked at 80°C for 12 hours. The lithium foil is then attached to the negative electrode film (the mass of the lithium foil is calculated according to C1=λ*C2+C3*η). A certain pressure is applied to the lithium foil and maintained for a period of time to complete the pre-lithiation. Finally, the tabs are soldered and adhesive is applied to obtain the negative electrode sheet.

[0045] 1.4 Lithium-ion battery preparation

[0046] The separator, negative electrode, separator, and positive electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to provide isolation. They are then wound into a bare cell. The lithium-ion battery is then manufactured through processes including casing, electrolyte injection, formation, and encapsulation.

[0047] Example 1

[0048] This embodiment provides a lithium-ion battery, the parameters of which are as follows:

[0049] The lithium-ion battery includes a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode comprises a 9 μm thick aluminum foil and a 3 μm thick safety coating, sequentially stacked. The inorganic filler is selected as iron phosphate with a median particle size of 0.2 μm. The mass ratio of iron phosphate, polyvinylidene fluoride, and conductive carbon black in the safety coating is 80:10:10. The mass ratio of lithium cobalt oxide, polyvinylidene fluoride, and conductive carbon black in the positive electrode active material layer is 97.6:1:1.4. The single-sided density of the positive electrode active material layer is 180.0 g / m³. 2 The coating length on side A is 1118 mm, the length on side B is 996 mm, and the electrode width is 76 mm. A single-sided side view of the positive electrode is shown below. Figure 1 As shown, 1 is the positive electrode current collector, 2 is the safety coating, and 3 is the positive electrode active material layer;

[0050] The negative electrode sheet comprises copper foil with a thickness of 8 μm and a single-sided density of 99.8 g / m², which are stacked sequentially. 2 The negative electrode active material layer and the pre-lithiation material have a coating length of 1130 mm on side A and 1017 mm on side B, and an electrode width of 77.5 mm. The mass ratio of artificial graphite, polyvinylidene fluoride and conductive carbon black in the negative electrode active material layer is 96:2:2. The pre-lithiation material is inert lithium powder.

[0051] In the lithium-ion battery, the first-efficiency of the positive electrode is 97%, the first-efficiency of the negative electrode is 92%, η = 5%, and λ = 0.7. The side view of the negative electrode is shown below. Figure 2 As shown, 4 is the negative electrode current collector, 5 is the negative electrode active material layer, and 6 is the pre-lithiation material.

[0052] The diaphragm is a 9μm polyethylene base membrane with 1μm adhesive coated on both sides, and the electrolyte is a 1mol / L LiPF6 / EC+DMC+EMC electrolyte (EC is ethylene carbonate, EMC is ethyl methyl carbonate, DMC is dimethyl carbonate, and the volume ratio of EC, DMC and EMC is 1:1:1).

[0053] Example 2

[0054] The only difference between this embodiment and Embodiment 1 is that the thickness of the safety coating is 0.5 μm; all other conditions and parameters are exactly the same as in Embodiment 1.

[0055] Example 3

[0056] The only difference between this embodiment and Embodiment 1 is that the thickness of the safety coating is 10 μm; all other conditions and parameters are exactly the same as in Embodiment 1.

[0057] Example 4

[0058] The only difference between this embodiment and Embodiment 1 is that the theoretical capacity ratio of the inorganic filler in the pre-lithiation material and the safety coating is 0.4:1 (i.e., λ = 0.4). All other conditions and parameters are exactly the same as in Embodiment 1.

[0059] Example 5

[0060] The only difference between this embodiment and Embodiment 1 is that the theoretical capacity ratio of the inorganic filler in the pre-lithiation material and the safety coating is 1.2:1 (i.e., λ = 1.2). All other conditions and parameters are exactly the same as in Embodiment 1.

[0061] Example 6

[0062] The only difference between this embodiment and Embodiment 1 is that the particle size of the inorganic filler in the safety coating is 0.05 μm; all other conditions and parameters are exactly the same as in Embodiment 1.

[0063] Example 7

[0064] The only difference between this embodiment and Embodiment 1 is that the particle size of the inorganic filler in the safety coating is 2 μm; all other conditions and parameters are exactly the same as in Embodiment 1.

[0065] Example 8

[0066] The only difference between this embodiment and Embodiment 1 is that the negative electrode pre-lithiation material is lithium foil; all other conditions and parameters are exactly the same as in Embodiment 1.

[0067] Comparative Example 1

[0068] This comparative example uses a conventional lithium-ion battery, meaning that no safety coating is added to the positive electrode and no lithium replenishing agent is added to the negative electrode. Other conditions and parameters are exactly the same as in Example 1.

[0069] Comparative Example 2

[0070] The only difference between this comparative example and Example 1 is that the inorganic filler in the safety coating of the positive electrode is lithium iron phosphate with the same molar amount of iron phosphate as in Example 1, and no pre-lithiation material is provided in the negative electrode. The molar amount of lithium iron phosphate is the same as that of iron phosphate in Example 1. All other conditions and parameters are exactly the same as in Example 1.

[0071] Comparative Example 3

[0072] The only difference between this comparative example and Example 1 is that no pre-lithiation material is provided on the negative electrode; all other conditions and parameters are exactly the same as in Example 1.

[0073] Performance testing:

[0074] 1. Needle prick test:

[0075] Charge the secondary battery at 1C current to the charging cutoff voltage, then maintain constant voltage charging until the current drops to 0.05C, then stop charging. A high-temperature resistant steel needle (with a cone angle of 45° at the tip) is inserted through the battery at a speed of 25 mm / s from a direction perpendicular to the battery plates. The insertion point should be close to the geometric center of the pierced surface. The steel needle remains in the battery, and the battery is observed for 1 hour to see if there are any signs of combustion or explosion.

[0076] 2. Compression test:

[0077] The secondary battery is fully charged at 1C current to the charging cutoff voltage, then charged at a constant voltage until the current drops to 0.05C, at which point charging is stopped. The battery is placed between two planes and pressed perpendicular to the plates, with a pressing force of 13.0kN ± 0.78kN applied between the two plates. The pressing test is stopped once the pressure reaches its maximum value. The battery must not experience an external short circuit during the test.

[0078] 3. Cyclic performance test

[0079] The cycle test conditions are as follows: at 25℃, the secondary battery is subjected to a 1C / 1C cycle test. The charge and discharge voltage range is determined according to the battery system. The test is stopped when the capacity decays to 80% of the first discharge specific capacity.

[0080] 4. Capacity test:

[0081] At 25℃, charge at a constant current of 0.2C to the upper limit of the cutoff voltage, then charge at a constant voltage with a cutoff current of 0.02C; let stand for 10 minutes; discharge at a constant current of 0.2C to the lower limit of the cutoff voltage, and record the discharge capacity at a cutoff current of 0.02C, which is the cell capacity.

[0082] To reduce systematic errors, 50 batteries were fabricated for each embodiment and comparative example for testing, and the lifespan and capacity were averaged and rounded to the nearest integer.

[0083] The test results are shown in Table 1:

[0084] Table 1

[0085] Needle prick test Extrusion test Cycle life / cycles Capacity / mAh Example 1 100% pass 100% pass 534 4891 Example 2 92% NG 86% NG 528 4905 Example 3 100% pass 100% pass 423 4776 Example 4 100% pass 100% pass 522 4735 Example 5 62% NG 48% NG 320 4884 Example 6 100% pass 100% pass 541 4792 Example 7 100% pass 100% pass 447 4815 Example 8 100% pass 100% pass 546 4889 Comparative Example 1 100% NG 100% NG 524 4885 Comparative Example 2 100% pass 100% pass 531 4821 Comparative Example 3 100% pass 100% pass 537 4703

[0086] As can be seen from Table 1, a comparison between Example 1 and Examples 2-3 shows that the thickness of the safety coating in the lithium-ion battery of the present invention affects its performance. When the thickness of the safety coating is controlled between 1 and 6 μm, the lithium-ion battery performs well. If the thickness of the safety coating is too large, the cycle life and capacity will be affected, and the battery thickness will also be affected, thus affecting the volumetric energy density. If the thickness of the safety coating is too small, the function of the safety coating cannot be realized.

[0087] Comparing Examples 1 and 4-5, it can be seen that in the lithium-ion battery of the present invention, the amount of pre-lithiation material added affects the battery performance. The capacity of the pre-lithiation material is C1, the capacity of the inorganic filler in the safety coating is C2, the capacity of the active material in the positive electrode active material layer is C3, and the first-time efficiency of the positive electrode minus the first-time efficiency of the negative electrode is η. C1 = λ*C2 + C3*η, where the lithium-ion battery has good performance when λ = 0.5 to 1. If λ is too large, it will lead to excessively rapid cycle life decay and seriously affect the safety test pass rate. This is because excessive active lithium leads to the formation of lithium dendrites during formation and cycling, resulting in capacity decay and easy internal short circuit. If λ is too small, it will affect the battery capacity.

[0088] A comparison of Examples 1 and 6-7 shows that in the lithium-ion battery of the present invention, the particle size of the inorganic filler in the safety coating affects the battery performance. If the particle size is too large, the lithium iron phosphate will be easily crushed during the rolling process, resulting in loss of electrical contact and affecting the battery performance. If the particle size is too small, the binder will encapsulate the active material, causing its capacity to be unable to be utilized.

[0089] A comparison of Examples 1 and 8 shows that using inert lithium powder or lithium foil as the pre-lithiation material can simultaneously lithilate the phosphate material in the positive electrode safety coating, replenish the active lithium ions consumed in the formation of the SEI and CEI films at both the positive and negative electrodes, thereby improving the battery energy density.

[0090] As can be seen from the comparison between Example 1 and Comparative Examples 1-2, the present invention provides a safety coating in the positive electrode and a pre-lithiation material in the negative electrode. The safety coating is a lithium-free phosphate, which is lithiated by the pre-lithiation material of the negative electrode during formation and cycling. With a reasonable system ratio, this design can not only improve battery safety, but also reduce battery cost and increase energy density. While the pre-lithiation material of the negative electrode lithiates the phosphate material in the positive electrode safety coating, it can also replenish the active lithium ions consumed by the formation of the SEI film and CEI film of the positive and negative electrodes, thereby improving the battery energy density.

[0091] As can be seen from the comparison of Example 1 and Comparative Examples 2 and 3, the energy density of the battery system in this invention is significantly lower than that of the system with pre-lithiation material without the addition of pre-lithiation material. This is because the pre-lithiation material can replenish the active lithium consumed by the SEI film and lithiate the iron phosphate.

[0092] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A lithium-ion battery, characterized in that, The lithium-ion battery includes a positive electrode and a negative electrode. The positive electrode includes a positive current collector, a positive active material layer, and a safety coating disposed between the positive current collector and the positive active material layer. The negative electrode includes a negative current collector, a negative active material layer disposed on the surface of the negative current collector, and a pre-lithiation material. The safety coating includes inorganic fillers, which include Fe. 1-x-y Mn x M y PO4, wherein 0≤x≤1, 0≤y≤0.1, 0≤x+y≤1, and M includes any one or at least two combinations of Sn, Cr, Mg, Ti, Al, Zn, W, Nb or Zr; The capacity C1 of the pre-lithiation material, the capacity C2 of the inorganic filler in the safety coating, the capacity C3 of the active material in the positive electrode active material layer, and the first-efficiency of the positive electrode - the first-efficiency of the negative electrode = η, satisfy the relationship C1 = λ*C2 + C3*η, where 0.5 ≤ λ ≤ 1, and η < 0 is taken as 0.

2. The lithium-ion battery as described in claim 1, characterized in that, The pre-lithiation material is disposed inside the negative electrode active material layer, between the negative electrode active material layer and the negative electrode current collector, or on the surface away from the negative electrode current collector.

3. The lithium-ion battery as described in claim 1, characterized in that, The positive electrode active material layer, safety coating, negative electrode active material layer, and pre-lithiation material all include binders and conductive agents.

4. The lithium-ion battery as described in claim 3, characterized in that, The adhesive includes any one or a combination of at least two of the following: polyvinylidene fluoride, modified polyvinylidene fluoride, polyvinylidene chloride, modified polyvinylidene chloride, polyvinylidene fluoride copolymer, polyvinylidene chloride copolymer, polymethyl methacrylate, or styrene-butadiene rubber.

5. The lithium-ion battery as described in claim 3, characterized in that, The conductive agent includes any one or a combination of at least two of conductive carbon black, acetylene black, graphite, graphene, carbon nanotubes, or carbon nanofibers.

6. The lithium-ion battery as described in claim 1, characterized in that, The positive electrode active material layer includes a positive electrode active material.

7. The lithium-ion battery as described in claim 6, characterized in that, The positive electrode active material includes any one or a combination of at least two of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese aluminum oxide, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, or lithium manganese silicate.

8. The lithium-ion battery as described in claim 1, characterized in that, The negative electrode active material layer includes a negative electrode active material.

9. The lithium-ion battery as described in claim 8, characterized in that, The negative electrode active material includes any one or a combination of at least two of graphite materials, silicon materials, silicon-carbon materials, or lithium titanate.

10. The lithium-ion battery as described in claim 9, characterized in that, The graphite materials include any one or a combination of at least two of the following: artificial graphite, natural graphite, hard carbon, soft carbon, or mesophase carbon microspheres.

11. The lithium-ion battery as described in claim 1, characterized in that, The pre-lithiation material includes inert lithium powder and / or lithium foil.

12. The lithium-ion battery as described in claim 1, characterized in that, The thickness of the safety coating is 0.05–30 μm.

13. The lithium-ion battery as described in claim 12, characterized in that, The thickness of the safety coating is 1–6 μm.

14. The lithium-ion battery as described in claim 1, characterized in that, Based on the mass of the safety coating being 100%, the inorganic filler accounts for 20-95% of the mass.

15. The lithium-ion battery as described in claim 14, characterized in that, Based on the mass of the safety coating being 100%, the inorganic filler accounts for 60-85% of the mass.

16. The lithium-ion battery as described in claim 3, characterized in that, The adhesive comprises 5% to 65% of the total mass.

17. The lithium-ion battery as described in claim 3, characterized in that, Preferably, the conductive agent has a mass percentage of 5-25%.

18. The lithium-ion battery as described in claim 1, characterized in that, The particle size of the inorganic filler is 0.02–100 μm.

19. The lithium-ion battery as described in claim 18, characterized in that, The particle size of the inorganic filler is 0.1–1 μm.

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