Dioxaphospholane electrolyte additive, electrolyte, and lithium-ion battery

Abstract

A dioxaphospholane electrolyte additive, an electrolyte, and a lithium-ion battery. The dioxaphospholane electrolyte additive has high solubility and low cost, and, when added to an electrolyte, can form a stable interfacial film at the positive and negative electrode interfaces of the battery, thereby better protecting the electrodes, reducing the generation of byproducts from the electrolyte at the positive and negative electrodes during cycling, suppressing the increase of positive and negative electrode impedance, enhancing the cycle life of the lithium-ion battery, and inhibiting DCR increase during cycling.

Description

Dioxaphospholane electrolyte additive, electrolyte and lithium ion battery

[0001] This disclosure claims priority to the Chinese patent application filed with the China Patent Office on February 29, 2024, with application number 202410225828.0, and the entire contents of the above application are incorporated by reference into this disclosure. Technical Field

[0002] The present disclosure relates to the technical field of lithium-ion batteries, and for example, to a dioxaphospholane electrolyte additive, an electrolyte, and a lithium-ion battery. Background Art

[0003] 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 commercial lithium-ion batteries include lithium manganese oxide, lithium cobalt oxide, ternary materials, and lithium iron phosphate, with their charge cutoff voltage generally not exceeding 4.2V. With technological advancements and the continuous development of the market, improving the energy density of lithium-ion batteries is becoming increasingly important and urgent. Ternary materials, as representatives of high energy density, have also been widely studied, and lithium difluorophosphate plays a crucial role in the ternary system.

[0004] Lithium difluorophosphate is used as an electrolyte additive. It can form an interface film rich in inorganic components at the interface of the positive and negative electrodes of the battery, stabilize the positive and negative electrode interfaces, and play a role in improving the cycle life of the lithium-ion battery and stabilizing the DCR growth. CN115692849A discloses a high-voltage ternary positive electrode material lithium-ion battery electrolyte and a lithium-ion battery containing the same. The high-voltage ternary positive electrode material lithium-ion battery electrolyte includes an organic solvent, a lithium salt and an additive; the additive includes a negative electrode film-forming additive, a functional additive and an antioxidant additive; 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 difluorooxalatoborate; the high-voltage ternary positive electrode material lithium-ion battery electrolyte provided by the invention has good high-voltage resistance and good cycle stability.

[0005] However, lithium difluorophosphate has a high cost and low solubility, making it unsuitable for large-scale industrial production applications.

[0006] Therefore, in order to solve the above technical problems, it is urgent to develop a dioxaphospholane electrolyte additive that can replace lithium difluorophosphate and form a stable interface film at the positive and negative electrode interfaces. Summary of the Invention

[0007] In a first aspect, the present disclosure provides a dioxaphospholane electrolyte additive, wherein the dioxaphospholane electrolyte additive has a structure shown in the following formula I:

[0008] Wherein, R is selected from any one of alkyl, alkoxy, F, Cl or Br.

[0009] The dioxaphospholane electrolyte additive having the structure shown in Formula I provided in the present disclosure has high solubility and relatively low cost. When added to the electrolyte, it can form a stable interface film at the positive and negative interface electrodes, better protect the positive and negative electrodes, and reduce the generation of by-products in the electrolyte on the positive and negative electrode sides during the cycle, thereby inhibiting the growth of the positive and negative electrode impedance, improving the cycle life of the lithium-ion battery and inhibiting the increase of DCR during the cycle.

[0010] In one embodiment, R is selected from methyl, ethyl, propyl, methoxy, ethoxy, propoxy, F, Cl or Br.

[0011] In a preferred embodiment, R is selected from F.

[0012] In one embodiment, the dioxaphospholane electrolyte additive has a structure as shown in the following formula II or formula III:

[0013] In the present disclosure, the dioxaphospholane electrolyte additive has a structure shown in Formula II. The dioxaphospholane electrolyte additive having the structure shown in Formula II contains a PF bond in its structure, which can generate LiF, an important component of SEI and CEI, during film formation at the positive and negative electrodes. When the positive and negative electrode active materials come into contact with the electrolyte, the continuous consumption of the electrolyte can be reduced.

[0014] In a second aspect, the present disclosure provides an electrolyte comprising a lithium salt, an organic solvent, and the dioxaphospholane electrolyte additive as described in the first aspect.

[0015] In one embodiment, the mass percentage of the dioxaphospholane electrolyte additive as described in the first aspect in the electrolyte is 0.2-4%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or 3.5%.

[0016] In one embodiment, the mass percentage of the dioxaphospholane electrolyte additive as described in the first aspect in the electrolyte is 0.5-2%.

[0017] In the present disclosure, the mass percentage of the dioxaphosphane electrolyte additive in the electrolyte is further limited to 0.2-4%. On the one hand, if the mass percentage of the dioxaphosphane electrolyte additive in the electrolyte is lower than 0.2%, it is easy to cause insufficient film formation at the positive and negative electrode interfaces, insufficient interface protection, and the electrolyte will continue to be consumed. On the other hand, if the mass percentage of the dioxaphosphane electrolyte additive in the electrolyte is higher than 4%, it is easy to cause the DCR of the manufactured lithium-ion battery to be too large, the power performance is reduced, and the capacity retention rate is reduced.

[0018] In one embodiment, the lithium salt includes lithium hexafluorophosphate. Selecting lithium hexafluorophosphate as the lithium salt can further enhance the conductivity, energy storage and environmental friendliness of the lithium-ion battery.

[0019] In one embodiment, the mass percentage of the lithium salt in the electrolyte is 10-17%, for example, 11%, 12%, 13%, 14%, 15% or 16%. By limiting the amount of lithium salt added to the above amount range, the role of lithium hexafluorophosphate can be better exerted.

[0020] In one embodiment, the organic solvent includes cyclic carbonate and / or chain carbonate.

[0021] In a preferred embodiment, the organic solvent is a combination of a cyclic carbonate and a chain carbonate.

[0022] In one embodiment, the volume ratio of the cyclic carbonate to the linear carbonate is (15-40):(60-85), such as 15:85, 20:80, 30:70 or 40:60.

[0023] In one embodiment, the cyclic carbonate includes any one of ethylene carbonate, propylene carbonate, butylene carbonate, or γ-butyrolactone, or a combination of at least two thereof.

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

[0025] In the present disclosure, the combination of the above-mentioned specific types of cyclic carbonates and chain carbonates can better avoid the damage of water to the electrolyte, and is also conducive to promoting the dissolution of the various components in the electrolyte more fully, thereby improving the synergy between the components and obtaining an electrolyte with excellent electrical properties.

[0026] In one embodiment, the electrolyte further includes other additives, and the other additives include any one of vinylene carbonate (VC), diethyl sulfate (DTD), or propane sultone (PS), or a combination of at least two thereof.

[0027] In the present disclosure, other additives are further added to the electrolyte, which can be combined with dioxaphospholane electrolyte additives to further improve the high-temperature cyclability and high-temperature storage properties of lithium-ion batteries; among them, VC can help form a dense and stable SEI film on the surface of the negative electrode, further reducing the reaction between the electrolyte and the negative electrode and reducing the consumption of the electrolyte; DTD can form a stable and elastic SEI film on the surface of the negative electrode, and at the same time can form a small amount of film on the surface of the positive electrode, further improving the stability of the positive and negative electrode interfaces; PS is a good positive electrode protection additive that can improve the high-temperature performance of lithium-ion batteries and reduce gas production.

[0028] In one embodiment, the mass percentage of other additives in the electrolyte is 0.01-5%, for example, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%.

[0029] In a preferred embodiment, the mass percentage of other additives in the electrolyte is 0.1-2%.

[0030] In a third aspect, the present disclosure provides a lithium-ion battery, comprising a positive electrode sheet, a negative electrode sheet, a separator, and the electrolyte as described in the second aspect.

[0031] The lithium-ion battery provided by the present disclosure includes the electrolyte as described in the second aspect, and has almost no gas production phenomenon, thereby having better electrical properties such as cycle stability.

[0032] In one embodiment, the positive electrode active material in the positive electrode sheet includes lithium transition metal oxide and / or lithium transition metal phosphate compound, preferably lithium transition metal oxide.

[0033] In one embodiment, the lithium transition metal oxide includes LiCoO2, 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 xO4 or Li2Mn 1-x Any one or a combination of at least two of O4;

[0034] 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 (for example, 0.2, 0.4, 0.6 or 0.8, etc.), 0≤y≤1 (for example, 0.2, 0.4, 0.6 or 0.8, etc.), 0≤z≤1 (for example, 0.2, 0.4, 0.6 or 0.8, etc.).

[0035] In one embodiment, the negative electrode active material in the negative electrode sheet includes any one of carbonaceous materials, alloy materials, or lithium-containing metal composite materials, or a combination of at least two thereof.

[0036] In one embodiment, 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, preferably any one or a combination of at least two of natural graphite, artificial graphite, soft carbon or hard carbon.

[0037] As a preferred technical solution of the present disclosure, selecting the above-mentioned positive electrode active material and negative electrode active material to match with the electrolyte can further improve the coordination 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.

[0038] Compared with the prior art, the present disclosure has the following beneficial effects:

[0039] The dioxaphospholane electrolyte additive provided by the present disclosure has a structure shown in Formula I. The dioxaphospholane electrolyte additive having the structure shown in Formula I has high solubility and relatively low cost. When added to the electrolyte, it can form a stable interface film at the positive and negative interface electrodes, better protect the positive and negative electrodes, and reduce the generation of by-products in the electrolyte on the positive and negative electrode sides during the cycle process, thereby inhibiting the growth of the positive and negative electrode impedance, improving the cycle life of the lithium-ion battery and inhibiting the increase of DCR during the cycle process. DETAILED DESCRIPTION

[0040] The following is a detailed description of the technical solution of the present disclosure. It should be understood by those skilled in the art that the embodiments are only for the purpose of helping to understand the present application and should not be regarded as a specific limitation of the present disclosure.

[0041] Example 1

[0042] A dioxaphospholane electrolyte additive, the structural formula of which is

[0043] Example 2

[0044] A dioxaphospholane electrolyte additive, the structural formula of which is

[0045] Example 3

[0046] A dioxaphospholane electrolyte additive, the structural formula of which is

[0047] Application Example 1

[0048] A lithium-ion battery comprising a positive electrode sheet, a negative electrode sheet, a separator and an electrode liquid;

[0049] The preparation method of the positive electrode sheet includes: 0.6 Co 0.1 Mn 0.3 O2), conductive agent Super-P and adhesive PVDF were mixed in N-methylpyrrolidone at a mass ratio of 96:2.0:2.0 to prepare a positive electrode slurry, and the positive electrode slurry was evenly coated on aluminum foil with a coating amount of 19 mg / cm 2 , then drying at 85°C, cold pressing, trimming, cutting and slitting, and finally drying at 85°C under vacuum conditions for 4 hours, welding the tabs to obtain the positive electrode sheet;

[0050] The preparation method of the negative electrode sheet includes: mixing artificial graphite, conductive agent Super-P, thickener CMC and adhesive SBR in a mass ratio of 96.5:1.0:1.0:1.5 in deionized water to form a negative electrode slurry, and then evenly coating the negative electrode slurry on a copper foil with a coating amount of 11.5 mg / cm 2 , then drying at 85°C, cold pressing, trimming, cutting and slitting, and finally drying at 110°C under vacuum conditions for 4 hours, welding the tabs to obtain the negative electrode sheet;

[0051] The diaphragm is PE film;

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

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

[0054] Application Examples 2-3

[0055] A lithium-ion battery differs from Application Example 1 in that the dioxaphospholane electrolyte additives provided in Examples 2 to 3 are used to replace the dioxaphospholane electrolyte additive provided in Example 1, and other materials, amounts and preparation methods are the same as those in Application Example 1.

[0056] Application Examples 4-9

[0057] A lithium-ion battery, which differs from Application Example 1 in that the mass percentages of the dioxaphospholane electrolyte additive provided in Example 1 in the electrolyte are 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 those in Application Example 1.

[0058] Application Example 10

[0059] A lithium ion battery is provided, which differs from Application Example 1 in that VC is not added to the electrolyte, the mass percentage of PS is 2%, and other materials, amounts and preparation methods are the same as those in Application Example 1.

[0060] Application Example 11

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

[0062] Application Example 12

[0063] A lithium-ion battery is provided, which differs from Application Example 1 in that PS and VC are not added to the electrolyte, and other materials, amounts used, and preparation methods are the same as those 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 to replace the dioxaphosphorane electrolyte additive provided in Example 1, and other materials, amounts and preparation methods are the same as those in Application Example 1.

[0066] Comparative Application Example 2

[0067] A lithium-ion battery differs from Application Example 1 in that the dioxaphospholane electrolyte additive provided in Example 1 is not added, and other materials, amounts, and preparation methods are the same as those in Application Example 1.

[0068] Performance testing:

[0069] (1) Normal temperature cycle capacity retention rate: The specific test method is: at 25°C, first charge the lithium ion battery to 4.4V at a constant current of 1C, then charge it at a constant voltage of 4.4V to a current of 0.05C, and then discharge it to 2.8V at a constant current of 1C. This is a charge and discharge cycle process, and the discharge capacity this time is the discharge capacity of the first cycle; the lithium ion battery is subjected to a cyclic charge and discharge test 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) DCR growth rate of normal temperature cycle: The specific test method is: at 25 ° C, the battery cells are tested after 0 cycles and 800 cycles respectively. The lithium-ion battery is first charged to 4.4V at a constant current of 0.33C, then charged at a constant voltage of 4.4V to a current of 0.05C, and then discharged at a constant current of 0.33C for 1.5h to 50% SOC, and then discharged at 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: at 45°C, first charge the lithium-ion battery to 4.4V at a constant current of 1C, then charge it at a constant voltage of 4.4V to a current of 0.05C, and then discharge it to 2.8V at a constant current of 1C. This is a charge and discharge cycle process, and the discharge capacity this time is the discharge capacity of the first cycle; the lithium-ion battery is subjected to a cyclic charge and discharge test 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: at 45°C, the battery cells are tested after 0 cycles and 600 cycles, respectively. The lithium-ion secondary battery is first charged to 4.4V at a constant current of 0.33C, then charged at a constant voltage of 4.4V to a current of 0.05C, and then discharged at a constant current of 0.33C for 1.5h to 50% SOC, and then discharged at a constant current of 1C for 30s; its 600-cycle DCR growth rate = 600-cycle DCR value / 0-cycle DCR value × 100%.

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

[0074] Table 1

[0075] According to the data in Table 1, we can see that:

[0076] Comparing the data of Application Examples 1 to 3 and Comparative Application Example 1, it can be seen that the dioxaphospholane electrolyte additive can more significantly improve the cycle capacity retention rate of lithium-ion batteries and reduce the cycle DCR growth rate compared with the lithium difluorophosphate additive;

[0077] Comparing the data of Application Examples 1 to 3 and Comparative Application Example 2, it can be seen that without the addition of the dioxaphospholane electrolyte additive, the cycle capacity retention rate and cycle DCR growth rate of the lithium-ion battery obtained are significantly deteriorated, indicating that the dioxaphospholane electrolyte additive can form a highly stable interface film in the ternary system, reduce the generation of by-products in the positive and negative electrode electrolytes during the cycle process, and inhibit the growth of the positive and negative electrode impedance;

[0078] Comparing the data of Application Example 1 and Application Examples 2-3, it can be seen that the dioxaphospholane electrolyte additive provided in Examples 2-3 is less effective than the dioxaphospholane electrolyte additive provided in Example 1. This is because the dioxaphospholane electrolyte additive provided in Examples 2-3 does not have a PF bond in its structure, and cannot generate LiF, an important component of SEI and CEI, during film formation at the positive and negative electrodes. Therefore, 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 interface film continues to thicken, resulting in a rapid increase in DCR and accelerated capacity decay.

[0079] Further comparison of the data of Application Example 1 and Application Examples 4 to 9 shows that as the amount of dioxaphospholane electrolyte additive added increases, its effect becomes more significant, improving the capacity retention rate of the lithium-ion battery at both room temperature and high temperature, and significantly suppressing the DCR growth rate after cycling, reducing the risk of lithium precipitation caused by the rapid growth of DCR. However, when the amount of dioxaphospholane electrolyte additive added exceeds a certain range, the effect of improving the cycle capacity retention rate is not significant.

[0080] Finally, by comparing the data of Application Example 1 and Application Examples 10 to 12, it can be seen that the performance of the lithium-ion batteries of Application Examples 10 to 12 is worse than that of Application Example 1. This is due to the lack of other additives. This indicates that further addition of other additives to the electrolyte can be combined with dioxaphospholane electrolyte additives to further improve the high-temperature cyclability and high-temperature storage properties of the lithium-ion battery.

[0081] The applicant declares that while the present disclosure illustrates a dioxaphospholane electrolyte additive, electrode solution, and lithium-ion battery through the aforementioned embodiments, the present disclosure is not limited to the aforementioned embodiments, meaning that implementation of the present disclosure does not necessarily rely on the aforementioned embodiments. Persons skilled in the art should understand that any improvements to the present disclosure, equivalent replacements for raw materials in the disclosed products, addition of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present disclosure.

Claims

1. A dioxaphospholane electrolyte additive, characterized in that: The dioxaphospholane electrolyte additive has a structure shown in the following formula I: Wherein, R is selected from any one of alkyl, alkoxy, F, Cl or Br.

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

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

4. The dioxaphospholane electrolyte additive according to claim 1, characterized in that: The dioxaphospholane electrolyte additive has a structure shown in the following formula II or formula III:

5. An electrolyte, characterized in that The electrolyte comprises a lithium salt, an organic solvent and the dioxaphospholane electrolyte additive according to any one of claims 1 to 4.

6. The electrolyte according to claim 5, characterized in that The mass percentage of the dioxaphospholane electrolyte additive according to any one of claims 1 to 4 in the electrolyte is 0.2 to 4%.

7. The electrolyte according to claim 6, characterized in that The mass percentage of the dioxaphospholane electrolyte additive according to any one of claims 1 to 4 in the electrolyte is 0.5 to 2%.

8. The electrolyte according to claim 5, characterized in that The lithium salt includes lithium hexafluorophosphate, and the mass percentage of the lithium salt in the electrolyte is 10-17%.

9. The electrolyte according to claim 5, characterized in that The organic solvent includes cyclic carbonate and / or chain carbonate.

10. The electrolyte according to claim 9, characterized in that The organic solvent is a combination of cyclic carbonate and chain carbonate; The volume ratio of the cyclic carbonate to the chain carbonate is (15-40):(60-85); The cyclic carbonate includes any one of ethylene carbonate, propylene carbonate, butylene carbonate or γ-butyrolactone, or a combination of at least two thereof; The linear carbonate includes any one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate or ethyl butyrate, or a combination of at least two thereof.

11. The electrolyte according to claim 5, characterized in that The electrolyte further includes other additives, wherein the other additives include any one or a combination of at least two of vinylene carbonate, vinyl sulfate or propane sultone; The mass percentage of other additives in the electrolyte is 0.01-5%.

12. The electrolyte according to claim 11, characterized in that The mass percentage of other additives in the electrolyte is 0.1-2%.

13. A lithium ion battery, characterized in that: The lithium-ion battery comprises a positive electrode sheet, a negative electrode sheet, a separator and the electrolyte according to any one of claims 5 to 12.

14. The lithium-ion battery according to claim 13, wherein: The positive electrode active material in the positive electrode sheet includes lithium transition metal oxide and / or lithium transition metal phosphate compound, preferably lithium transition metal oxide; The lithium transition metal oxides include LiCoO2, 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 a combination of at least two of O4; 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, 0≤y≤1, 0≤z≤1.

15. The lithium-ion battery according to claim 13, wherein The negative electrode active material in the negative electrode sheet includes any one of carbonaceous materials, alloy materials or lithium-containing metal composite materials, or a combination of at least two thereof; 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 is more preferably any one or a combination of at least two of natural graphite, artificial graphite, soft carbon or hard carbon.

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