Electrolyte and energy storage lithium ion battery

Abstract

The present disclosure provides an electrolyte and an energy storage lithium ion battery, and belongs to the technical field of energy storage lithium ion batteries. The electrolyte comprises a non-aqueous solvent, a lithium salt, a first functional additive, a second functional additive and an auxiliary additive; wherein the chemical formula of the first functional additive is shown as formula I: R1 is independently selected from hydrogen, C1-C6 alkyl, substituted carbonyl and substituted alkenyl; the chemical formula of the second functional additive is shown as formula II: R2 is independently selected from C1-C5 alkyl and C2-C5 alkenyl; R3 is independently selected from C1-C5 alkyl, C2-C5 alkenyl and C2-C5 alkynyl; and R4 is independently selected from C1-C5 alkyl and C2-C5 alkenyl. The combination of electrolyte additives can improve the chemical properties of the electrolyte and the electrode interface, and effectively improve the thermal runaway problem caused by overcharging of high-nickel batteries.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of energy storage lithium ion batteries, and particularly relates to an electrolyte for improving overcharge and an energy storage lithium ion battery. BACKGROUND

[0002] Ternary lithium batteries have become the mainstream system of power batteries due to their high energy density, but the overcharge safety problem is still a key bottleneck restricting development. Under normal charging conditions, lithium ions are released from the positive electrode and then embedded into the negative electrode, which reduces the negative electrode potential and increases the positive electrode potential. When the potential difference between the positive electrode and the negative electrode reaches the highest voltage designed for lithium ion batteries, the charging is stopped, and at this time, the battery is in a full charge state. However, when abnormal charging occurs, the lithium ion power battery may continue to charge after reaching the full charge state, resulting in overcharge. After overcharge occurs, the positive electrode material will collapse due to excessive delithiation, and the decomposition of electrolyte and the oxidation of separator will be intensified, which will significantly increase the risk of thermal runaway. The lithium ion battery triggers thermal runaway, causing safety problems of lithium batteries. Although external circuit protection can partially alleviate this problem, the capacity difference of single batteries may still cause local overcharge, and external protection increases system complexity and cost. Therefore, it is particularly important to develop internal electrochemical protection mechanisms, and electrolyte additives are the focus of research because they directly act on the reaction interface. Developing additives with high oxidation potential, fast response and no effect on battery cycle is one of the core directions to improve the intrinsic safety of ternary batteries. SUMMARY

[0003] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides an electrolyte and an energy storage lithium ion battery.

[0004] In one aspect of the present disclosure, an electrolyte is provided, comprising: a non-aqueous solvent, a lithium salt, a first functional additive, a second functional additive, and an auxiliary additive; wherein,

[0005] The chemical formula of the first functional additive is shown as formula I:

[0006] Formula I;

[0007] wherein R1 is independently selected from one of hydrogen, C1-C6 alkyl, substituted carbonyl and substituted alkenyl;

[0008] The chemical formula of the second functional additive is shown as formula II:

[0009] Formula II;

[0010] The second functional additive contains an unsaturated bond.

[0011] each R2is independently selected from one of C1-C5 alkyl, C2-C5 alkenyl;

[0012] each R3is independently selected from one of C1-C5 alkyl, C2-C5 alkenyl, C2-C5 alkynyl;

[0013] each R4is independently selected from one of C1-C5 alkyl, C2-C5 alkenyl.

[0014] Optionally, the R1is selected from one of hydrogen, C1-C3 alkyl, carbonyl substituted with trimethylsilyl, and alkenyl substituted with trimethylsilyl.

[0015] Optionally, the first functional additive is selected from at least one of the following compounds:

[0016] Formula I-1;

[0017] Formula I-2;

[0018] Formula I-3;

[0019] Formula I-4;

[0020] Formula I-5;

[0021] Formula I-6.

[0022] Optionally, the second functional additive is selected from at least one of the following compounds:

[0023] Formula II-1;

[0024] Formula II-2;

[0025] Formula II-3.

[0026] Optionally, the mass ratio of the first functional additive and the second functional additive is (0.5-1):(0.3-1). The content of the first functional additive can be preferably 0.5-1%, and the content of the second functional additive can be preferably 0.3-1%.

[0027] Optionally, the non-aqueous solvent includes cyclic carbonate and chain carbonate.

[0028] Optionally, the lithium salt is one or both of lithium hexafluorophosphate and lithium bisfluorosulfonylimide;

[0029] The lithium salt accounts for 12% to 15% of the total mass of the electrolyte.

[0030] Optionally, the auxiliary additive comprises a sulfur-containing additive and a lithium salt additive; wherein,

[0031] The sulfur-containing additive accounts for 0.5% to 1.0% of the total mass of the electrolyte.

[0032] The lithium salt additive accounts for 0.5% to 1.0% of the total mass of the electrolyte.

[0033] Optionally, the sulfur-containing additive comprises at least one of 1,3-propylene sulfite and ethylene sulfate.

[0034] The lithium salt additive comprises at least one of lithium difluorophosphate, lithium bisoxalate borate, and lithium tetrafluoroborate.

[0035] Another aspect of the present disclosure provides a storage lithium ion battery, which comprises a positive electrode sheet, a negative electrode sheet, a separator, and the electrolyte as described above.

[0036] The present disclosure provides an electrolyte and a storage lithium ion battery, wherein the electrolyte comprises a non-aqueous solvent, a lithium salt, a first functional additive, a second functional additive, and an auxiliary additive; wherein the first functional additive has the following formula I: Formula I; wherein in formula I, each R1 is independently selected from one of hydrogen, C1-C6 alkyl, substituted carbonyl, and substituted alkenyl; and the second functional additive has the following formula II: Formula II; wherein in formula II, each R2 is independently selected from one of C1-C5 alkyl and C2-C5 alkenyl; each R3 is independently selected from one of C1-C5 alkyl, C2-C5 alkenyl, and C2-C5 alkynyl; and each R4 is independently selected from one of C1-C5 alkyl and C2-C5 alkenyl. The present disclosure can improve the chemical properties of the electrolyte and the electrode interface by using the additive combination of the electrolyte, effectively improve the thermal runaway problem caused by overcharging of high-nickel batteries, and improve the safety performance of the battery. The additive combination has a broad application prospect. DETAILED DESCRIPTION

[0037] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be described in further detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present disclosure.

[0038] In one aspect of the present disclosure, an electrolyte capable of improving overcharge is provided, the electrolyte comprising a non-aqueous solvent, a lithium salt, a first functional additive, a second functional additive, and an auxiliary additive; wherein the first functional additive has a chemical formula as shown in Formula I: Formula I; wherein in Formula I, each R1 is independently selected from one of hydrogen, C1-C6 alkyl, substituted carbonyl, and substituted alkenyl; and the second functional additive has a chemical formula as shown in Formula II: Formula II; wherein in Formula II, each R2 is independently selected from one of C1-C5 alkyl and C2-C5 alkenyl; each R3 is independently selected from one of C1-C5 alkyl, C2-C5 alkenyl, and C2-C5 alkynyl; and each R4 is independently selected from one of C1-C5 alkyl and C2-C5 alkenyl.

[0039] In the present embodiment, the first functional additive contains a cyano group (-C≡N-), which electrochemically polymerizes at high voltage during overcharge, forms a conductive polymer layer on the surface of the positive electrode, blocks the current, and the trimethylsilyl group provides a steric hindrance effect, delays the side reaction of the cyano group at normal working voltage, avoids the premature increase of the internal resistance of the battery, thereby reducing the temperature rise during overcharge. The second functional additive contains an unsaturated bond, which undergoes free radical polymerization at a higher voltage to form an interpenetrating network structure with the polymer layer in the first functional additive, enhancing the strength and ion conductivity of the film. In addition, the vinyl or alkynyl group polymerization consumes free radicals, reduces the generation of H2 / CO gas, and the phosphate group (P=O) preferentially adsorbs on the surface of the positive electrode, reducing the interfacial impedance and providing active sites for the polymerization reaction. That is, the combination of electrolyte additives can improve the chemical properties of the electrolyte and electrode interface, effectively improve the thermal runaway problem caused by overcharge of high-nickel batteries, and improve the safety performance of the battery. The additive combination has broad application prospects.

[0040] In some preferred embodiments, each R1 in the first functional additive is selected from one of hydrogen, C1-C3 alkyl, trimethylsilyl-substituted carbonyl, and trimethylsilyl-substituted alkenyl.

[0041] As a further preferred aspect, the first functional additive is selected from at least one of the following compounds:

[0042] Formula I-1 (CAS: 725270-27-9);

[0043] Formula I-2 (CAS: 107325-81-5);

[0044] Formula I-3 (CAS: 866364-30-9);

[0045] Formula I-4 (CAS: 100-47-0);

[0046] Formula I-5 (p-Tolunitrile);

[0047] Formula I-6 (p-Ethylbenzonitrile).

[0048] In some preferred embodiments, the second functional additive is selected from at least one of the following compounds:

[0049] Formula II-1 (CAS: 113419-25-3);

[0050] Formula II-2 (CAS: 2401881-57-8);

[0051] Formula II-3 (CAS: 2401882-41-3).

[0052] In some preferred embodiments, the mass ratio of the first functional additive and the second functional additive is (0.5-1):(0.3-1). That is, the mass fraction of the first functional additive in the total mass of the electrolyte is 0.5-1%, and the mass fraction of the second functional additive in the total mass of the electrolyte is 0.3-1%.

[0053] In some preferred embodiments, the lithium salt is one or both of lithium hexafluorophosphate (LiPF6) and lithium bisfluorosulfonylimide (LiFSi). In addition, the mass fraction of the lithium salt in the total mass of the electrolyte is 12%~15%.

[0054] In some preferred embodiments, the auxiliary additive includes a sulfur-containing additive and a lithium salt additive.

[0055] As a further preferred solution, the sulfur-containing additive includes at least one of 1,3-propene sultone (PST) and ethylene sulfate (DTD). In addition, the added amount of the sulfur-containing additive has a mass fraction of 0.5%~1.0% in the total mass of the electrolyte.

[0056] As a further preferred solution, the lithium salt additive includes at least one of lithium difluorophosphate (LiPO2F2), lithium bis(oxalato)borate, lithium tetrafluoroborate (LiBF4). In addition, the added amount of the lithium salt additive has a mass fraction of 0.5%~1.0% in the total mass of the electrolyte.

[0057] In some preferred embodiments, the content of the non-aqueous solvent is the balance other than the first functional additive, the second functional additive, the lithium salt and the auxiliary additive, i.e., in the electrolyte, the total content of the non-aqueous solvent, the lithium salt and the first functional additive, the second functional additive and the auxiliary additive is 100%, wherein the non-aqueous solvent includes the cyclic carbonate and the chain carbonate.

[0058] As a further preferred solution, the cyclic carbonate includes ethylene carbonate, propylene carbonate and fluoroethylene carbonate, and the chain carbonate includes dimethyl carbonate and methyl ethyl carbonate; it is noted that, for the component of the non-aqueous solvent, when the total mass thereof is 100%, the content of the cyclic carbonate component (ethylene carbonate, propylene carbonate and fluoroethylene carbonate) in the total mass of the non-aqueous solvent is 20% to 25%, the content of dimethyl carbonate in the chain carbonate in the total mass of the non-aqueous solvent is 55% to 65%, and the content of methyl ethyl carbonate in the chain carbonate in the total mass of the non-aqueous solvent is 15% to 25%.

[0059] Further, the electrolyte of the present embodiment is prepared by the following method:

[0060] Under an argon atmosphere, the first functional additive and the second functional additive, the lithium salt, the sulfur-containing additive and the lithium salt additive are added to the non-aqueous solvent, and stirred and mixed at a temperature of 8 to 12°C for 2 to 4 hours to obtain the electrolyte.

[0061] In another aspect of the present disclosure, a kind of energy storage lithium ion battery is provided, which comprises positive pole piece, negative pole piece, diaphragm and the electrolyte described above, and the specific components of the electrolyte are described above, which will not be repeated here.

[0062] The electrolyte additive combination described above is added to the electrolyte in the present disclosure, and the prepared electrolyte exhibits excellent performance when the battery is overcharged, thereby improving the safety performance of the battery. The additive combination in the electrolyte can form a stable polymer layer to block the current during overcharging. These advantages make the electrolyte of the present disclosure have a wide application prospect in the field of energy storage lithium ion batteries.

[0063] The electrolyte capable of improving overcharging and its additives will be further described below in combination with specific embodiments:

[0064] Example 1

[0065] The present embodiment provides an electrolyte additive composition and electrolyte, which are specifically as follows:

[0066] According to the mass percentage of the components, the electrolyte formula used in the present embodiment is as follows: the first functional additive (such as formula I-1 ): 0.5%, the second functional additive (such as formula II-1 ): 0.3%, LiPO2F2: 0.5%, PST: 0.5%, LiPF6: 12.5%, the balance being non-aqueous solvent components, i.e. the content of non-aqueous solvent is 85.7%. Among them, the non-aqueous solvent components in the above electrolyte formula are composed of fluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, wherein the proportion of ethylene carbonate in the total mass of non-aqueous solvent is 15%, the proportion of propylene carbonate in the total mass of non-aqueous solvent is 5%, the proportion of fluoroethylene carbonate in the total mass of non-aqueous solvent is 3%, the proportion of dimethyl carbonate in the total mass of non-aqueous solvent is 55%, and the proportion of methyl ethyl carbonate in the total mass of non-aqueous solvent is 22%.

[0067] The above electrolyte is prepared by the following method: under an argon atmosphere, adding the compounds represented by formula I-1 and formula II-1, lithium difluorophosphate, 1,3-propylene sulfone, lithium hexafluorophosphate into the non-aqueous solvent formed by mixing methyl ethyl carbonate, ethylene carbonate and dimethyl carbonate, propylene carbonate, fluoroethylene carbonate, stirring and mixing at 10°C for 3h to obtain the electrolyte.

[0068] Example 2

[0069] This example provides an electrolyte additive composition and electrolyte, which are specifically as follows:

[0070] The first functional additive is a compound represented by formula I-2 ( ), the second functional additive is an additive represented by formula II-1 ( ), and the addition amount is 0.5%, and the others are the same as in Example 1.

[0071] Example 3

[0072] This example provides an electrolyte additive composition and electrolyte, which are specifically as follows:

[0073] The first functional additive is a compound represented by formula I-3 ( ), the addition amount is 0.5%, the second functional additive is an additive represented by formula II-1 ( ), the addition amount is 0.5%, and the others are the same as in Example 1.

[0074] Example 4

[0075] This example provides an electrolyte additive composition and electrolyte, with the addition amount of the first functional additive as a variable, the addition amount is 0.7%, and the others are the same as in Example 1.

[0076] Example 5

[0077] The present example provides an electrolyte additive composition and electrolyte, with the first functional additive added in an amount of 1%, and the other components being the same as in Example 1.

[0078] Example 6

[0079] The present example provides an electrolyte additive composition and electrolyte, with the first functional additive added in an amount of 1%, and the other components being the same as in Example 1.

[0080] The first functional additive is a compound represented by Formula I-1 , added in an amount of 0.5%, and the second functional additive is an additive represented by Formula II-2 , added in an amount of 0.5%, and the other components are the same as in Example 1.

[0081] Example 7

[0082] The present example provides an electrolyte additive composition and electrolyte, with the first functional additive added in an amount of 1%, and the other components being the same as in Example 1.

[0083] The first functional additive is a compound represented by Formula I-2 , added in an amount of 0.5%, and the second functional additive is an additive represented by Formula II-2 , added in an amount of 1%, and the other components are the same as in Example 1.

[0084] Example 8

[0085] The present example provides an electrolyte additive composition and electrolyte, with the first functional additive added in an amount of 1%, and the other components being the same as in Example 1.

[0086] The first functional additive is a compound represented by Formula I-3 , added in an amount of 0.5%, and the second functional additive is an additive represented by Formula II-2 , added in an amount of 1%, and the other components are the same as in Example 1.

[0087] Example 9

[0088] The present example provides an electrolyte additive composition and electrolyte, with the first functional additive added in an amount of 1%, and the other components being the same as in Example 1.

[0089] The first functional additive is a compound represented by Formula I-1 , added in an amount of 0.5%, and the second functional additive is an additive represented by Formula II-3 , added in an amount of 0.7%, and the other components are the same as in Example 1.

[0090] Example 10

[0091] The present example provides an electrolyte additive composition and electrolyte, with the first functional additive added in an amount of 1%, and the other components being the same as in Example 1.

[0092] The first functional additive is a compound represented by Formula I-2 ), at an addition amount of 0.5%, the second functional additive is an additive represented by Formula II-3 ), at an addition amount of 0.7%, and the rest is the same as in Example 1.

[0093] Example 11

[0094] This example provides an electrolyte additive composition and electrolyte, which are as follows:

[0095] The first functional additive is a compound represented by Formula I-3 ), at an addition amount of 0.5%, the second functional additive is an additive represented by Formula II-3 ), at an addition amount of 1%, and the rest is the same as in Example 1.

[0096] Example 12

[0097] This example provides an electrolyte additive composition and electrolyte, which are as follows:

[0098] With reference to the electrolyte formulation employed in Example 6, the addition amount of the sulfur-containing additive included in the formulation is taken as a variable, and the difference from Example 1 is that the PST addition amount is adjusted to 0.7%, and the rest is the same as in Example 6.

[0099] Example 13

[0100] This example provides an electrolyte additive composition and electrolyte, which are as follows:

[0101] With reference to the electrolyte formulation employed in Example 6, the addition amount of the sulfur-containing additive included in the formulation is taken as a variable, and the difference from Example 1 is that the PST addition amount is adjusted to 1%, and the rest is the same as in Example 6.

[0102] Example 14

[0103] This example provides an electrolyte additive composition and electrolyte, which are as follows:

[0104] With reference to the electrolyte formulation employed in Example 6, the addition amount of the sulfur-containing additive included in the formulation is taken as a variable, and the difference from Example 1 is that the PST addition amount is adjusted to 0.5%, and vinyl sulfonate (DTD) is added at an addition amount of 0.5%, and the rest is the same as in Example 6.

[0105] Example 15

[0106] This example takes the electrolyte formulation employed in Example 1 as a reference, and the type of lithium salt additive included in the formulation is taken as a variable, and the difference from Example 1 is that the addition amount of LiPO2F2 is 0.8%, and the rest is the same as in Example 1.

[0107] Example 16

[0108] This example takes the electrolyte formulation used in Example 1 as a reference, takes the type of lithium salt additive included in the formulation as a variable, and differs from Example 1 in that the addition amount of LiPO2F2 is 0.5%, and lithium tetrafluoroborate (LiBF4) is added at an addition amount of 0.2%, and the rest is the same as Example 1.

[0109] Example 17

[0110] This example takes the electrolyte formulation used in Example 1 as a reference, takes the content of lithium hexafluorophosphate included in the formulation as a variable, and differs from Example 1 in that the content of lithium hexafluorophosphate is adjusted to 15%, and the content of the non-aqueous solvent component used is reduced or increased in equal mass, and the rest is the same as Example 1.

[0111] Example 18

[0112] This example takes the electrolyte formulation used in Example 1 as a reference, takes the content of lithium hexafluorophosphate included in the formulation as a variable, and differs from Example 1 in that the content of lithium hexafluorophosphate is adjusted to 12%, lithium bisfluorosulfonylimide (LiFSi) is added at an addition amount of 3%, and the content of the non-aqueous solvent component used is reduced or increased in equal mass, and the rest is the same as Example 1.

[0113] Comparative Example 1

[0114] This comparative example provides an electrolyte, which differs from Example 1 only in that the electrolyte functional additive is not contained in the comparative example, and the non-aqueous solvent component used is used to replace the electrolyte functional additive in the electrolyte formulation of Example 1 in equal mass, and the rest is the same as Example 1.

[0115] Comparative Example 2

[0116] This comparative example provides an electrolyte, which differs from Example 1 only in that the first functional additive is not contained in Comparative Example 2, and the non-aqueous solvent component used is used to replace the electrolyte functional additive in the electrolyte formulation of Example 1 in equal mass, and the rest is the same as Example 1.

[0117] The electrolytes prepared in Examples 1-18 and Comparative Examples 1-2 are used to prepare batteries, wherein:

[0118] Further, graphite is used as a negative active material, and the graphite, silicon-carbon, conductive agent, and binder are prepared into a negative electrode slurry in a mass percentage of 93.4:4:1.5:1.1, and the negative electrode slurry is coated on a copper foil current collector, vacuum dried, and a negative electrode sheet is prepared;

[0119] The NCM811 is used as the positive active material, the positive active material, the conductive agent and the binder are prepared into the positive slurry in a mass ratio of 97.0:1.5:2.0, the positive slurry is coated on the aluminum foil current collector, vacuum drying, and the positive electrode sheet is prepared;

[0120] The electrolyte prepared by the examples 1-18 and the comparative examples 1-2 is respectively assembled with the above positive electrode sheet, negative electrode sheet and separator to form a cylindrical battery, and the initial normal temperature cycle 300 weeks capacity retention rate and overcharge SOC of the battery are detected, and the specific results are as follows:

[0121] Table 1 Battery detection data

[0122]

[0123] As shown in Table 1, the results of comparative examples 1-18 and comparative examples 1-2 show that the benzene nitrile additive has a higher overcharge SOC protection range, and the overcharge SOC protection range is further improved after adding the unsaturated silane containing phosphate additive, which is mainly because the first functional additive and the second functional additive form a conductive polymer layer on the surface of the positive electrode, which widens the overcharge protection window, thereby improving the overcharge performance of the battery.

[0124] The present disclosure provides an electrolyte and an energy storage lithium ion battery, which has the following beneficial effects compared with the prior art: the electrolyte additive combination effectively improves the thermal runaway problem of high-nickel batteries during overcharge by improving the chemical properties of the electrolyte and the electrode interface, and improves the safety performance of the battery. The additive combination has broad application prospects.

[0125] It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered as the protection scope of the present disclosure.

Claims

1. An electrolyte, characterized in that, include: Non-aqueous solvents, lithium salts, primary functional additives, secondary functional additives, and auxiliary additives; among which, The chemical formula of the first functional additive is shown in Formula I below: Formula I; Each of R1 is independently selected from one of hydrogen, C1-C6 alkyl, substituted carbonyl and substituted alkenyl; The chemical formula of the second functional additive is shown in Formula II below: Formula II; The second functional additive contains unsaturated bonds; R2 is independently selected from one of C1-C5 alkyl groups and C2-C5 alkenyl groups; R3 is independently selected from one of C1-C5 alkyl, C2-C5 alkenyl, and C2-C5 alkynyl groups; R4 is independently selected from one of the C1-C5 alkyl group or the C2-C5 alkenyl group.

2. The electrolyte according to claim 1, characterized in that, R1 is selected from one of hydrogen, C1-C3 alkyl groups, carbonyl groups substituted with trimethylsilane, and alkenyl groups substituted with trimethylsilane.

3. The electrolyte according to claim 2, characterized in that, The first functional additive is selected from at least one of the following compounds: Formula I-1; Formula I-2; Formula I-3; Formula I-4; Formula I-5; Formula I-6.

4. The electrolyte according to claim 1, characterized in that, The second functional additive is selected from at least one of the following compounds: Formula II-1; Formula II-2; Formula II-3.

5. The electrolyte according to any one of claims 1 to 4, characterized in that, The mass ratio of the first functional additive to the second functional additive is (0.5-1):(0.3-1).

6. The electrolyte according to any one of claims 1 to 4, characterized in that, The non-aqueous solvents include cyclic carbonates and chain carbonates.

7. The electrolyte according to any one of claims 1 to 4, characterized in that, The lithium salt is one or both of lithium hexafluorophosphate and lithium difluorosulfonylimide. The lithium salt accounts for 12% to 15% of the total mass of the electrolyte.

8. The electrolyte according to any one of claims 1 to 4, characterized in that, The auxiliary additives include sulfur-containing additives and lithium salt additives; wherein... The sulfur-containing additive accounts for 0.5% to 1.0% of the total mass of the electrolyte; The lithium salt additive accounts for 0.5% to 1.0% of the total mass of the electrolyte.

9. The electrolyte according to claim 8, characterized in that, The sulfur-containing additive includes at least one of 1,3-propenesulfonate lactone and vinyl sulfate. The lithium salt additive includes at least one of lithium difluorophosphate, lithium bis(oxalato)borate, and lithium tetrafluoroborate.

10. An energy storage lithium-ion battery, characterized in that, The energy storage lithium-ion battery includes a positive electrode, a negative electrode, a separator, and an electrolyte as described in any one of claims 1-9.

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