A phosphorus-pyrocyclopentane-based electrolyte additive, electrolyte, and lithium-ion battery

Abstract

This invention provides a phosphorus-pyrocyclopentane electrolyte additive, an electrolyte, and a lithium-ion battery. The phosphorus-pyrocyclopentane electrolyte has the structure shown in Formula I. The phosphorus-pyrocyclopentane electrolyte additive with the structure shown in Formula I has high solubility and relatively low cost. When added to the electrolyte, it can form a stable interfacial film at the positive and negative electrodes of the battery, better protecting the positive and negative electrodes, reducing the generation of by-products in the electrolyte on the positive and negative electrode sides during cycling, thereby inhibiting the growth of the positive and negative electrode impedance, improving the cycle life of the lithium-ion battery, and inhibiting the growth of DCR during cycling.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a phosphorus dioxane-based electrolyte additive, an electrolyte, and a lithium-ion battery. Background Technology

[0002] With the development of the new energy industry, lithium-ion batteries have become dominant due to their high operating voltage and high energy density. Currently, the main cathode materials for commercially used lithium-ion batteries include lithium manganese oxide, lithium cobalt oxide, ternary materials, and lithium iron phosphate, with a charging cut-off voltage generally not exceeding 4.2V. With technological advancements and continuous market development, improving the energy density of lithium-ion batteries has become increasingly important and urgent. Ternary materials, as representatives of high energy density, have been extensively studied, and lithium difluorophosphate plays a crucial role in the ternary system.

[0003] Lithium difluorophosphate, as an electrolyte additive, can form an interface film rich in inorganic components at the positive and negative electrode interfaces of the battery, stabilizing the interface and improving the cycle life and stabilizing the DCR growth of lithium-ion batteries. CN115692849A discloses a high-voltage ternary cathode material lithium-ion battery electrolyte and a lithium-ion battery containing the same. The high-voltage ternary cathode material lithium-ion battery electrolyte includes an organic solvent, a lithium salt, and additives; the additives include a negative electrode film-forming additives, functional additives, and antioxidant additives; the negative electrode film-forming additive is any one or a combination of at least two of vinylene carbonate, fluoroethylene carbonate, and vinyl sulfate; the functional additive is selected from lithium difluorophosphate and / or lithium difluorooxalate borate; the high-voltage ternary cathode material lithium-ion battery electrolyte provided by this invention has good high-voltage resistance and good cycle stability.

[0004] However, lithium difluorophosphate is expensive and has low solubility, making it unsuitable for large-scale industrial production.

[0005] Therefore, in order to address the above-mentioned technical problems, there is an urgent need to develop a dioxophosphate heterocyclopentane electrolyte additive that can replace lithium difluorophosphate and form a stable interfacial film at the positive and negative electrode interfaces. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a phosphorus-pyrocyclopentane-based electrolyte additive, an electrolyte, and a lithium-ion battery. The phosphorus-pyrocyclopentane-based electrolyte additive has a low cost and can form a stable interfacial film at the positive and negative electrodes, thereby better protecting the positive and negative electrodes, improving the cycle life of the lithium-ion battery, and suppressing the growth of DCR during cycling.

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

[0008] In a first aspect, the present invention provides a phosphorus-containing heterocyclic pentane electrolyte additive, wherein the phosphorus-containing heterocyclic pentane electrolyte additive has the structure shown in Formula I:

[0009]

[0010] R is selected from any one of alkyl, alkoxy, F, Cl or Br.

[0011] The dioxophosphorus heterocyclopentane electrolyte additive provided by this invention has high solubility and relatively low cost. When added to the electrolyte, it can form a stable interfacial film at the positive and negative electrodes, better protect the positive and negative electrodes, reduce the generation of by-products in the electrolyte on the positive and negative electrode sides during cycling, thereby inhibiting the growth of the positive and negative electrode impedance, improving the cycle life of lithium-ion batteries and inhibiting the growth of DCR during cycling.

[0012] Preferably, R is selected from methyl, ethyl, propyl, methoxy, ethoxy, propoxy, F, Cl or Br, and more preferably F.

[0013] Preferably, the dioxophosphorus heterocyclic pentane electrolyte additive has the structure shown in Formula II or Formula III:

[0014]

[0015] Preferably, the dioxophosphorus heterocyclic pentane electrolyte additive has the structure shown in Formula II. The structure of the dioxophosphorus heterocyclic pentane electrolyte additive with the structure shown in Formula II contains PF bonds. When forming films at the positive and negative electrodes, it can generate LiF, an important component of SEI and CEI. When the positive and negative electrode active materials are in contact with the electrolyte, it can reduce the continuous consumption of the electrolyte.

[0016] In a second aspect, the present invention provides an electrolyte comprising a lithium salt, an organic solvent, and a dioxophosphate heterocyclopentane electrolyte additive as described in the first aspect.

[0017] Preferably, the mass percentage of the dioxophosphorus heterocyclopentane electrolyte additive in the electrolyte, as described in the first aspect, is 0.2% to 4%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or 3.5%, and more preferably 0.5% to 2%.

[0018] As a preferred technical solution, the present invention further limits the mass percentage content of dioxophosphorus heterocyclopentane electrolyte additives in the electrolyte to 0.2% to 4%. On the one hand, if the mass percentage content of dioxophosphorus heterocyclopentane electrolyte additives in the electrolyte is less than 0.2%, it is easy to cause insufficient film formation at the positive and negative electrode interfaces, resulting in inadequate interface protection and continuous consumption of the electrolyte. On the other hand, if the mass percentage content of dioxophosphorus heterocyclopentane electrolyte additives in the electrolyte is greater than 4%, it is easy to cause excessive DCR after the lithium-ion battery is manufactured, resulting in reduced power performance and decreased capacity retention.

[0019] Preferably, the lithium salt includes lithium hexafluorophosphate. Selecting lithium hexafluorophosphate as the lithium salt can further enhance the conductivity, energy storage capacity, and environmental friendliness of lithium-ion batteries.

[0020] Preferably, the lithium salt in the electrolyte has a mass percentage of 10-17%, such as 11%, 12%, 13%, 14%, 15%, or 16%, etc. Limiting the amount of lithium salt added within the above range can better exert the function of lithium hexafluorophosphate.

[0021] Preferably, the organic solvent comprises cyclic carbonates and / or chain carbonates, more preferably a combination of cyclic carbonates and chain carbonates.

[0022] Preferably, the volume ratio of the cyclic carbonate to the chain carbonate is (15-40):(60-85), for example, 15:85, 20:80, 30:70 or 40:60.

[0023] Preferably, the cyclic carbonate includes any one or a combination of at least two of ethylene carbonate, propylene carbonate, butene carbonate, or γ-butyrolactone.

[0024] Preferably, the chain carbonate includes any one or a combination of at least two of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, or ethyl butyrate.

[0025] As a preferred technical solution of the present invention, selecting the above-mentioned specific types of cyclic carbonates and chain carbonates for combination can better avoid the damage of water to the electrolyte, and also help to promote the more complete dissolution of each component in the electrolyte, thereby improving the synergy between the components and obtaining an electrolyte with excellent electrical properties.

[0026] Preferably, the electrolyte further includes other additives, which include any one or a combination of at least two of vinylene carbonate (VC), vinyl sulfate (DTD), or propane sulfonate lactone (PS).

[0027] As a preferred embodiment of the present invention, further addition of other additives to the electrolyte can be combined with dioxophosphorus heterocyclopentane electrolyte additives to further improve the high-temperature cycle performance and high-temperature storage performance of lithium-ion batteries. Among them, VC can assist in the formation of a dense and stable SEI film on the negative electrode surface, further reducing the reaction between the electrolyte and the negative electrode and reducing electrolyte consumption; DTD can form a stable and elastic SEI film on the negative electrode surface, and can also form a small amount of film on the positive electrode surface, further improving the stability of the positive and negative electrode interface; PS is a good positive electrode protection additive that can improve the high-temperature performance of lithium-ion batteries and reduce gas production.

[0028] Preferably, the mass percentage of other additives in the electrolyte is 0.01-5%, such as 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or 4.5%, and more preferably 0.1-2%.

[0029] Thirdly, the present invention provides a lithium-ion battery, the lithium-ion battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte as described in the second aspect.

[0030] The lithium-ion battery provided by the present invention includes the electrolyte as described in the second aspect, with almost no gas generation, thereby exhibiting superior electrical performance such as cycle stability.

[0031] Preferably, the positive electrode active material in the positive electrode sheet includes lithium transition metal oxides and / or lithium transition metal phosphate compounds, and more preferably lithium transition metal oxides.

[0032] Preferably, the lithium transition metal oxide includes LiCoO2 and LiNi. x Co y Mn z O2, LiNi x Mn y O2, LiMn2O4, LiMnO2, Li2MnO4, Li 1+a Mn 1-x M x O2, LiCo 1-x M x O2, LiMn 1-x M x O4 or Li2Mn 1-x Any one or at least two of O4;

[0033] Wherein, M is selected from any one of Ni, Co, Mn, Al, Cr, Mg, Zr, Mo, V or Ti, 0≤a<0.2, 0≤x≤1 (e.g. 0.2, 0.4, 0.6 or 0.8), 0≤y≤1 (e.g. 0.2, 0.4, 0.6 or 0.8), 0≤z≤1 (e.g. 0.2, 0.4, 0.6 or 0.8).

[0034] Preferably, the negative electrode active material in the negative electrode sheet includes any one or a combination of at least two of carbonaceous materials, alloy materials, or lithium-containing metal composite materials.

[0035] Preferably, the negative electrode active material includes any one or a combination of at least two of natural graphite, artificial graphite, soft carbon, hard carbon, lithium titanate, silicon, silicon-carbon alloy or silicon-oxygen alloy, and more preferably any one or a combination of at least two of natural graphite, artificial graphite, soft carbon or hard carbon.

[0036] As a preferred technical solution of the present invention, selecting the above-mentioned positive electrode active material and negative electrode active material to combine with the electrolyte can further improve the synergistic effect between the electrolyte and the positive and negative electrode sheets, and further improve the cycle stability and high-temperature storage performance of the lithium-ion battery.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The phosphorus-pyrocyclopentane electrolyte additive provided by this invention has the structure shown in Formula I. The phosphorus-pyrocyclopentane electrolyte additive with the structure shown in Formula I has high solubility and relatively low cost. When added to the electrolyte, it can form a stable interfacial film at the positive and negative electrodes, better protect the positive and negative electrodes, reduce the generation of by-products in the electrolyte on the positive and negative electrodes during cycling, thereby inhibiting the growth of the positive and negative electrode impedance, improving the cycle life of lithium-ion batteries, and inhibiting the growth of DCR during cycling. Detailed Implementation

[0039] 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.

[0040] Unless otherwise specified, the raw materials involved in the specific embodiments of this invention are all conventional materials in the art and can be purchased commercially.

[0041] Example 1

[0042] A phosphorus-containing heterocyclic pentane electrolyte additive, with the following structural formula:

[0043] Example 2

[0044] A phosphorus-containing heterocyclic pentane electrolyte additive, with the following structural formula:

[0045] Example 3

[0046] A phosphorus-containing heterocyclic pentane electrolyte additive, with the following structural formula:

[0047] Application Example 1

[0048] A lithium-ion battery includes a positive electrode, a negative electrode, a separator, and an electrode solution;

[0049] The preparation method of the positive electrode includes: preparing lithium nickel cobalt manganese oxide (LiNiO2). 0.6 Co 0.1 Mn 0.3 O2), conductive agent Super-P, and binder PVDF were mixed evenly in N-methylpyrrolidone at a mass ratio of 96:2.0:2.0 to prepare a positive electrode slurry. The positive electrode slurry was then uniformly coated onto aluminum foil with a coating amount of 19 mg / cm². 2 After drying at 85°C, the material is cold-pressed, trimmed, cut into sheets and slits, and finally dried under vacuum at 85°C for 4 hours. The tabs are then welded to obtain the positive electrode sheet.

[0050] The method for preparing the negative electrode sheet includes: mixing artificial graphite, conductive agent Super-P, thickener CMC, and binder SBR in deionized water at a mass ratio of 96.5:1.0:1.0:1.5 to form a negative electrode slurry; then uniformly coating the negative electrode slurry onto copper foil with a coating amount of 11.5 mg / cm². 2 After drying at 85°C, the material is cold-pressed, trimmed, cut into sheets and slits, and finally dried under vacuum at 110°C for 4 hours. The tabs are then welded to obtain the negative electrode sheet.

[0051] The diaphragm is a PE membrane;

[0052] The electrolyte preparation method includes: based on the total mass of the electrolyte (100%), the lithium salt accounts for 12.5% ​​of the total mass of the electrolyte, specifically lithium hexafluorophosphate; an organic solvent is a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC), wherein the volume ratio of EC:EMC:DEC is 30:50:20; and electrolyte additives include 0.5% of phosphorus heterocyclopentane electrolyte additive (Example 1), 1% of vinylene carbonate (VC), and 1% of propane sulfonate lactone (PS) by mass.

[0053] The lithium-ion battery preparation method provided in this application example includes: stacking the above-mentioned positive electrode sheet, negative electrode sheet and separator to form a cell with a thickness of 8 mm, a width of 60 mm and a length of 130 mm; vacuum baking the cell at 85°C for 10 h; injecting electrolyte and letting it stand for 24 h; then charging it to 4.4 V with a constant current of 0.1 C (200 mA); then charging it at a constant voltage of 4.4 V until the current drops to 0.05 C (100 mA); then discharging it to 2.8 V with a constant current of 0.1 C (200 mA); repeating the charge and discharge cycle twice; and finally charging it to 3.8 V with a constant current of 0.1 C (200 mA) to obtain the lithium-ion battery.

[0054] Application Examples 2-3

[0055] A lithium-ion battery differs from Application Example 1 in that the phosphorus-pyrocyclopentane electrolyte additives provided in Examples 2 and 3 are used instead of the phosphorus-pyrocyclopentane electrolyte additives provided in Example 1. Other materials, dosages, and preparation methods are the same as in Application Example 1.

[0056] Application Examples 4-9

[0057] A lithium-ion battery differs from Application Example 1 in that the mass percentage of the dioxophosphorus heterocyclopentane electrolyte additive provided in Example 1 in the electrolyte is 1% (Application Example 4), 2% (Application Example 5), 4% (Application Example 6), 0.2% (Application Example 7), 0.1% (Application Example 8), and 5% (Application Example 9), respectively; other materials, amounts, and preparation methods are the same as in Application Example 1.

[0058] Application Example 10

[0059] A lithium-ion battery differs from Application Example 1 in that no vitamin C is added to the electrolyte, the mass percentage of PS is 2%, and the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0060] Application Example 11

[0061] A lithium-ion battery differs from Application Example 1 in that no PS is added to the electrolyte, the mass percentage of VC is 2%, and the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0062] Application Example 12

[0063] A lithium-ion battery differs from Application Example 1 in that PS and VC are not added to the electrolyte, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0064] Comparative Application Example 1

[0065] A lithium-ion battery differs from Application Example 1 in that lithium difluorophosphate is used instead of the dioxophosphate heterocyclopentane electrolyte additive provided in Example 1, while the other materials, dosages, and preparation methods are the same as in Application Example 1.

[0066] Comparative Application Example 2

[0067] A lithium-ion battery differs from Application Example 1 in that it does not contain the phosphorus dioxane-based electrolyte additive provided in Example 1, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0068] Performance testing:

[0069] (1) Capacity retention rate during room temperature cycling: The specific test method is as follows: At 25℃, the lithium-ion battery is first charged to 4.4V with a constant current of 1C, then charged to 0.05C with a constant voltage of 4.4V, and then discharged to 2.8V with a constant current of 1C. This is one charge-discharge cycle. The discharge capacity of this cycle is the discharge capacity of the first cycle. The lithium-ion battery is cycled and charged and discharged in the above manner, and the discharge capacity of the 800th cycle is taken. The capacity retention rate (%) of the lithium-ion battery after 800 cycles = (discharge capacity of the 800th cycle / discharge capacity of the first cycle) × 100%.

[0070] (2) Room temperature cycle DCR growth rate: The specific test method is as follows: At 25℃, the cells after 0 cycles and 800 cycles are tested respectively. First, the lithium-ion battery is charged to 4.4V with a constant current of 0.33C, then charged to 0.05C with a constant voltage of 4.4V, then discharged to 50% SOC with a constant current of 0.33C for 1.5h, and then discharged with a constant current of 1C for 30s. The DCR growth rate of 800 cycles = DCR value of 800 cycles / DCR value of 0 cycles × 100%.

[0071] (3) High-temperature cycle capacity retention rate: The specific test method is as follows: At 45℃, the lithium-ion battery is first charged to 4.4V with a constant current of 1C, then charged to 0.05C with a constant voltage of 4.4V, and then discharged to 2.8V with a constant current of 1C. This is one charge-discharge cycle process, and the discharge capacity of this cycle is the discharge capacity of the first cycle. The lithium-ion battery is cycled and charged and discharged in the above manner, and the discharge capacity of the 600th cycle is taken. The capacity retention rate (%) of the lithium-ion battery after 600 cycles = (discharge capacity of the 600th cycle / discharge capacity of the first cycle) × 100%.

[0072] (4) High-temperature cycle DCR growth rate: The specific implementation method is as follows: At 45℃, the cells after 0 cycles and 600 cycles are tested respectively. First, the lithium-ion secondary battery is charged to 4.4V with a constant current of 0.33C, then charged to 0.05C with a constant voltage of 4.4V, then discharged to 50% SOC with a constant current of 0.33C for 1.5h, and then discharged with a constant current of 1C for 30s; its DCR growth rate over 600 cycles = DCR value of 600 cycles / DCR value of 0 cycles × 100%.

[0073] The lithium-ion batteries provided in Test Cases 1-12 and Comparative Application Examples 1-2 were tested according to the above test methods. The test results are shown in Table 1.

[0074] Table 1

[0075]

[0076]

[0077] According to the data in Table 1:

[0078] Comparing the data from Application Examples 1-3 and Comparative Application Example 1, it can be seen that, compared with lithium difluorophosphate additives, phosphorus dioxane-based electrolyte additives can significantly improve the cycle capacity retention rate of lithium-ion batteries and reduce the cycle DCR growth rate.

[0079] Comparing the data from Application Examples 1-3 and Comparative Application Example 2, it can be seen that without the addition of phosphorus-pyrocyclopentane electrolyte additives, the cycle capacity retention rate and cycle DCR growth rate of the lithium-ion batteries are significantly deteriorated. This indicates that phosphorus-pyrocyclopentane electrolyte additives can form a highly stable interfacial film in the ternary system, reduce the generation of by-products in the electrolyte on both the positive and negative electrodes during cycling, and suppress the growth of the positive and negative electrode impedance.

[0080] Comparing the data from Application Example 1 and Application Examples 2-3, it can be seen that the phosphorus heterocyclopentane electrolyte additives provided in Examples 2-3 are less effective than those provided in Example 1. This is because the phosphorus heterocyclopentane electrolyte additives provided in Examples 2-3 lack PF bonds in their structure, and therefore cannot generate LiF, an important component of SEI and CEI, during the formation of films at the positive and negative electrodes. Consequently, the positive and negative electrode interfaces are not dense and stable enough. When the positive and negative electrode active materials come into contact with the electrolyte, the electrolyte is continuously consumed, and the interfacial film continues to thicken, leading to a rapid increase in DCR and accelerated capacity decay.

[0081] Further comparison of the data from Application Example 1 and Application Examples 4-9 shows that as the amount of phosphorus dioxane-based electrolyte additives increases, their effect becomes more significant, improving the capacity retention rate of lithium-ion batteries at both room temperature and high temperature, and significantly suppressing the DCR growth rate after cycling, reducing the risk of lithium plating drop caused by rapid DCR growth. However, when the amount of phosphorus dioxane-based electrolyte additives exceeds a certain range, the effect on improving cycle capacity retention becomes insignificant.

[0082] Finally, comparing the data from Application Example 1 and Application Examples 10-12, it can be seen that the performance of the lithium-ion batteries in Application Examples 10-12 is worse than that in Application Example 1. This is because no other additives were added. This indicates that adding other additives to the electrolyte, in combination with dioxophosphate heterocyclopentane electrolyte additives, can further improve the high-temperature cycle performance and high-temperature storage performance of lithium-ion batteries.

[0083] The applicant declares that this invention illustrates a phosphorus dioxane-based electrolyte additive, electrode solution, and lithium-ion battery through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product, addition of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. An electrolyte, characterized by, The electrolyte comprises a lithium salt, an organic solvent, and a phospholane electrolyte additive having a structure shown in Formula I: Formula I; wherein R is selected from any one of an alkyl group, an alkoxy group, F, Cl, or Br; The mass percentage of the phospholane electrolyte additive in the electrolyte is 1.5-2%. The electrolyte further comprises other additives, which include vinylene carbonate and propanesultone, and the mass percentage of the other additives in the electrolyte is 0.01-5%.

2. The electrolyte according to claim 1, characterized in that, The R is selected from any one of a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, a propoxy group, F, Cl, or Br.

3. The electrolyte according to claim 2, characterized in that, The R is selected from F.

4. The electrolyte of claim 1, wherein The phospholane electrolyte additive has a structure shown in Formula II or Formula III: Formula II; Formula III.

5. The electrolyte of claim 1, wherein The lithium salt comprises lithium hexafluorophosphate.

6. The electrolyte of claim 1, wherein The mass percentage of the lithium salt in the electrolyte is 10-17%.

7. The electrolyte of claim 1, wherein The organic solvent comprises a cyclic carbonate and / or a chain carbonate.

8. The electrolyte of claim 7, wherein, The organic solvent is a combination of a cyclic carbonate and a chain carbonate.

9. The electrolyte of claim 8, wherein, The volume ratio of the cyclic carbonate to the chain carbonate is (15-40):(60-85).

10. The electrolyte of claim 7, wherein, The cyclic carbonate comprises any one of or a combination of at least two of vinylene carbonate, propylene carbonate, or butylene carbonate.

11. The electrolyte of claim 7, wherein, The chain carbonate comprises any one of or a combination of at least two of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, or ethyl propyl carbonate.

12. The electrolyte of claim 1, wherein, The mass percentage of the other additives in the electrolyte is 0.1-2%.

13. A lithium-ion battery, characterized by, The lithium ion battery comprises a positive electrode sheet, a negative electrode sheet, a separator, and the electrolyte according to any one of claims 1-12.

14. The lithium-ion battery of claim 13, wherein, The positive electrode active material in the positive electrode sheet comprises a lithium transition metal oxide and / or a lithium transition metal phosphate compound.

15. The lithium-ion battery of claim 14, wherein, The positive electrode active material in the positive electrode sheet is a lithium transition metal oxide.

16. The lithium-ion battery of claim 13, wherein, The negative electrode active material in the negative electrode sheet comprises any one of or a combination of at least two of a carbonaceous material, an alloy material, a lithium-containing metal composite material, or silicon.

17. The lithium-ion battery of claim 16, wherein, The negative electrode active material comprises any one of or a combination of at least two of natural graphite, artificial graphite, soft carbon, hard carbon, lithium titanate, silicon-carbon alloy, or silicon-oxygen alloy.

18. The lithium-ion battery of claim 17, wherein, The negative electrode active material comprises any one of or a combination of at least two of natural graphite, artificial graphite, soft carbon, or hard carbon.

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