Lithium battery electrolyte additive, electrolyte and lithium battery

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a lithium battery electrolyte additive, an electrolyte and a lithium battery, the lithium battery electrolyte additive comprises lithium trifluoromethanesulfonate and an additive component A. The additive component A has dicyano groups, and the mass ratio of the lithium trifluoromethanesulfonate to the additive component A is (0.5%-1%): (0.5%-1%), anions in the lithium trifluoromethanesulfonate have high oxidation stability and can inhibit oxygenolysis of the electrolyte at high temperature, and meanwhile, the charge delocalization effect of the lithium trifluoromethanesulfonate can improve the transference number of lithium ions and reduce concentration polarization; the dicyano group of the additive component A is preferentially complexed with dissolved transition metal ions, forms a compact interfacial film on the surface of a positive electrode, inhibits side reactions, and cooperates with lithium trifluoromethanesulfonate to reduce the polarization voltage of the battery, improve the initial DCR, improve the rate discharge performance and the high-temperature storage performance, and improve the performance of the lithium ion battery; the problem of poor high-temperature stability of the lithium ion battery in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a lithium battery electrolyte additive, electrolyte and lithium battery. BACKGROUND

[0002] With the technological innovation of new energy vehicles, wearable electronic devices and portable mobile terminals, lithium ion batteries as the core power source and energy storage unit have put forward unprecedentedly high requirements on their comprehensive performance. High energy density, excellent high-temperature storage stability and excellent large-rate discharge capability have become key indicators for judging battery performance and determining application scenarios. Among many lithium ion battery cathode materials, nickel-cobalt-manganese (NCM) or nickel-cobalt-aluminum (NCA) ternary materials have become the preferred solution to meet the demand for long driving range due to their significantly higher energy density than lithium iron phosphate (LFP) and other materials, and are widely used in electric vehicles and other fields. However, ternary materials, especially high-nickel (Ni≥60%) systems, while pursuing higher energy density, face severe challenges of high-temperature storage performance degradation and insufficient large-rate discharge capability, as well as the risk of thermal runaway. Among them, the stability of ternary lithium ion batteries in high-temperature environments has become a key bottleneck restricting technological development. When ternary batteries are stored or used in high-temperature environments (such as summer sun-exposed car interiors and high-power operating conditions), the side reactions between the cathode material and the electrolyte will be significantly intensified, leading to irreversible consumption of active lithium ions, dissolution of transition metal ions (especially Ni 4+ ), continuous decomposition of the electrolyte, and thickening and destabilization of the solid electrolyte interface (SEI) film. Therefore, high temperatures not only accelerate the decomposition of the electrolyte and the degradation of the electrode material structure, but also may trigger interface side reactions and the risk of thermal runaway. Therefore, breakthroughs in high-temperature resistant battery technology have become the focus of attention of the industry and academia. SUMMARY

[0003] In view of the poor high-temperature stability of lithium ion batteries in the prior art, the present application provides a lithium battery electrolyte additive, electrolyte and lithium battery.

[0004] To achieve the above-mentioned purpose, the technical scheme is adopted as follows:

[0005] The present application provides a lithium battery electrolyte additive, which comprises lithium trifluoromethyl sulfonate and an additive component A. The additive component A has a dicyano group, and the mass ratio of lithium trifluoromethyl sulfonate to additive component A is (0.5%-1%):(0.5%-1%).

[0006] Optionally, the general formula of the additive component A is:

[0007] R is any one of a self-substituted or unsubstituted alkyl group having 2-6 carbon atoms, a substituted or unsubstituted phenyl group, a carbonyl group substituted with a phenyl group, or a pyridyl group.

[0008] Optionally, a sulfur-based additive component is further included, and the mass ratio of the sulfur-based additive component, the carbonate-based additive component, and the lithium salt component to the lithium trifluoromethylsulfonate is (0.5%-1%):(0.5%-1%):(0.5%-1%):(0.5%-1%).

[0009] Optionally, the sulfur-based additive component includes one or both of 1,3-propane sultone and 1,3-propene sultone.

[0010] Optionally, the carbonate-based additive component includes vinylene carbonate.

[0011] Optionally, the lithium salt component includes lithium hexafluorophosphate.

[0012] Optionally, the lithium salt component further includes one of lithium difluorophosphate and lithium difluoro oxalate borate.

[0013] An electrolyte includes an organic solvent component and the lithium battery electrolyte additive described above, and the mass concentration of lithium trifluoromethylsulfonate in the electrolyte is 0.5%-1%.

[0014] Optionally, the organic solvent component includes dimethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, and ethyl methyl carbonate, and the mass ratio of the total mass of the fluorinated vinylene carbonate and the vinylene carbonate to the mass of the dimethyl carbonate and the ethyl methyl carbonate is (20-25):(2-70):(10-20).

[0015] A lithium battery includes the electrolyte described above or the lithium battery electrolyte additive described above.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] The application provides a lithium battery electrolyte additive, which comprises lithium trifluoromethyl sulfonate and an additive component A, the additive component A has a dicyano group, and the mass ratio of the lithium trifluoromethyl sulfonate to the additive component A is (0.5-1) :(0.5-1). The anion in the lithium trifluoromethyl sulfonate has high oxidation stability, can effectively inhibit the oxidative decomposition of the electrolyte at high temperature, and the charge delocalization effect of the lithium trifluoromethyl sulfonate can improve the lithium ion migration number and reduce the concentration polarization. In addition, the lithium trifluoromethyl sulfonate is a high-conductivity lithium salt, the strong anion (CF3SO3-) of which can significantly improve the ionic conductivity of the electrolyte, and the excellent thermal stability and chemical stability of the lithium trifluoromethyl sulfonate can help to widen the electrochemical window of the electrolyte and reduce the decomposition reaction at high temperature or high voltage. The additive component A contains a dicyano group, which can be preferentially complexed with dissolved transition metal ions, form a dense interface film on the positive electrode surface, inhibit the side reaction, and under the synergistic effect of the two additives, the lithium trifluoromethyl sulfonate provides high bulk phase conductivity, and the additive component A optimizes the interface kinetics, thereby reducing the polarization voltage of the battery, improving the initial direct current resistance (DCR), improving the rate discharge performance and high-temperature storage performance, and improving the performance of the lithium ion battery.

[0018] The sulfur-based additive component, the carbonate-based additive component and the lithium salt component are further included, and the mass ratio of the sulfur-based additive component, the carbonate-based additive component and the lithium salt component to the lithium trifluoromethyl sulfonate is (0.5-1) :(0.5-1) :(0.5-1) :(0.5-1). The sulfur-based additive component can form a dense and stable cathode electrolyte interphase (CEI) and SEI film on the surface of the positive electrode and the negative electrode, can effectively inhibit the continuous reaction between the electrode surface and the electrolyte, improve the transmission rate of lithium ions, reduce the interface impedance, and thus improve the rate performance and cycle stability of the battery; the carbonate-based additive component can form an SEI film, and the SEI film structure is compact and does not increase the impedance, can effectively prevent the further decomposition of the electrolyte, and thus improve the cycle stability of the battery; and the addition of the lithium salt component can dissociate lithium ions in the solvent, and the ions realize the transfer of electric charge by migration in the process of charging and discharging of the battery.

[0019] The lithium salt component comprises lithium hexafluorophosphate, the solubility of lithium hexafluorophosphate in the organic solvent is high, the association degree is small, and the lithium hexafluorophosphate is easy to dissociate, so as to ensure the high ionic conductivity of the electrolyte, the lithium salt component further comprises lithium difluorophosphate and lithium difluoro oxalate borate, which can further promote the formation of a stable SEI film, effectively inhibit the side reaction between the electrode and the electrolyte, reduce the interface impedance of the battery, and thus improve the cycle life and rate performance of the battery.

[0020] The application provides an electrolyte, comprising an organic solvent component and the lithium battery electrolyte additive, the mass concentration of lithium trifluoromethyl sulfonate in the electrolyte is 0.5% to 1%, the electrolyte can effectively improve ion conductivity and low-temperature performance, excellent interface stability and thermal stability, can reduce the risk of thermal runaway of the battery and prolong the cycle life of the battery while improving the charge-discharge efficiency and environmental adaptability of the lithium ion battery, and promotes high-end applications in the fields of electric vehicles, energy storage systems and the like.

[0021] The application also provides a lithium battery comprising the electrolyte or the lithium battery electrolyte additive, the battery has higher energy density and rate performance, longer cycle life and better safety, can effectively improve the safety and reliability of the electric vehicle, meets the high-performance requirements of the electric vehicle and energy storage, is expected to realize more extensive applications in the fields of electric vehicles, energy storage systems, aerospace and the like, and promotes revolutionary progress of battery technology. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 EIS diagrams of the electrolytes prepared for example 1, example 2, comparative example 1 and comparative example 2 after 40 days of storage at 60 DEG C.

[0023] Figure 2 Linear sweep curve diagram of example 1 of the application. DETAILED DESCRIPTION

[0024] To enable persons skilled in the art to understand the features and effects of the application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used in the text are the usual meanings understood by those skilled in the art for the application, and in the event of conflict, the definitions in the specification shall prevail.

[0025] Theories or mechanisms described and disclosed herein, whether correct or not, should not be taken as limiting the scope of the application, i.e., the application can be practiced without relying on any particular theory or mechanism.

[0026] In this text, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are for the sake of brevity and convenience. Therefore, the description of numerical ranges or percentage ranges should be considered to have covered and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0027] In this text, unless otherwise specified, "comprising", "including", "containing", "having" or similar words cover the meaning of "consisting of" and "consisting essentially of", for example, "A comprising a" covers the meaning of "A comprising a and other" and "A comprising only a".

[0028] Herein, all possible combinations of the various technical features described in the various embodiments or examples are not described, in order to simplify the description. Therefore, the various technical features in the various embodiments or examples can be combined in any manner as long as there is no contradiction, and all possible combinations should be considered as falling within the scope of the present specification.

[0029] The present application is further described in detail by the following Examples. It is to be understood that the examples are only used to illustrate the present application and not intended to limit the scope of the present application. Furthermore, it is to be understood that various modifications and changes can be made to the present application by those skilled in the art after understanding the content of the present application, and such equivalent forms should fall within the scope of the appended claims.

[0030] The following examples use the apparatuses and devices that are conventional in the art. The experimental methods in the following examples, unless otherwise specified, are usually carried out according to the conventional conditions, or according to the conditions suggested by the manufacturers. The following examples use various raw materials, unless otherwise specified, and the conventional commercially available products are used, and the specifications are conventional specifications in the art. In the specification of the present application and the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0031] The present application is further described in detail by the following Examples. It is to be understood that the examples are only used to illustrate the present application and not intended to limit the scope of the present application. Furthermore, it is to be understood that various modifications and changes can be made to the present application by those skilled in the art after understanding the content of the present application, and such equivalent forms should fall within the scope of the appended claims.

[0032] The present application discloses a lithium battery electrolyte additive, comprising lithium triflate and additive component A, the additive component A has a dicyano group, the mass ratio of lithium triflate to additive component A is (0.5%-1%):(0.5%-1%), and the general formula of the additive component A is:

[0033] wherein R is any one of self-substituted or unsubstituted alkyl with carbon atom number of 2-6, substituted or unsubstituted phenyl, carbonyl substituted by phenyl, or pyridyl.

[0034] In a preferred embodiment, the lithium battery electrolyte additive further comprises a sulfur additive component, the mass ratio of the sulfur additive component, the carbonate additive component and the lithium salt component to lithium trifluoromethanesulfonate is (0.5%-1%):(0.5%-1%):(0.5%-1%):(0.5%-1%), further, the sulfur additive component comprises one or both of 1,3-propane sultone and 1,3-propene sultone, the carbonate additive component comprises vinylene carbonate, the lithium salt component comprises lithium hexafluorophosphate, and the lithium salt component further comprises one of lithium difluorophosphate and lithium difluoro(oxalato)borate.

[0035] The anion in lithium trifluoromethanesulfonate in the lithium battery electrolyte additive has high oxidation stability, which can effectively inhibit the oxidative decomposition of the electrolyte at high temperature, and the charge delocalization effect of lithium trifluoromethanesulfonate improves the lithium ion migration number and reduces the concentration polarization. The additive component A contains a dicyano group, which can preferentially complex with dissolved transition metal ions, form a dense interface film on the positive electrode surface, inhibit side reactions, and under the synergistic action of the two additives, lithium trifluoromethanesulfonate provides high bulk phase conductivity, additive component A optimizes the interface kinetics, thereby reducing the polarization voltage of the battery, improving the initial DCR, improving the rate discharge performance and high-temperature storage performance, and improving the performance of lithium ion batteries.

[0036] The application also provides an electrolyte comprising an organic solvent component and the above-mentioned lithium battery electrolyte additive, the mass concentration of lithium trifluoromethanesulfonate in the electrolyte is 0.5%-1%. The organic solvent component comprises a cyclic carbonate and a chain carbonate, the chain carbonate comprises dimethyl carbonate and methyl ethyl carbonate; the cyclic carbonate comprises fluoroethylene carbonate and vinylene carbonate; the mass ratio of the total mass of fluoroethylene carbonate and vinylene carbonate to the mass of dimethyl carbonate and methyl ethyl carbonate is (20-25):(2-70):(10-20). The electrolyte can effectively improve the ionic conductivity and low-temperature performance, excellent interface stability and thermal stability, improve the charge-discharge efficiency and environmental adaptability of lithium ion batteries, reduce the risk of thermal runaway of the battery, prolong the cycle life of the battery, and promote its high-end application in the fields of electric vehicles, energy storage systems, etc.

[0037] The application also provides a lithium battery comprising the above-mentioned electrolyte or the above-mentioned lithium battery electrolyte additive, the battery has higher energy density and rate performance, longer cycle life and better safety, can effectively improve the safety and reliability of electric vehicles, meet the high-performance requirements of electric vehicles and energy storage, and is expected to be more widely used in the fields of electric vehicles, energy storage systems, aerospace, etc., and promote revolutionary progress in battery technology.

[0038] The application will be further described in connection with the following examples, but is not limited thereto.

[0039] Example 1

[0040] The electrolyte used in this example includes organic solvent component, lithium trifluoromethanesulfonate, additive component A, carbonate additive component, sulfur additive component and lithium salt component, calculated in terms of mass percentage of components; the mass concentration of lithium trifluoromethanesulfonate is 0.5%; the additive component A is 2-(2-fluorobenzoyl)-malononitrile, the molecular formula is The mass percentage of additive component A is 0.5%; the carbonate additive component is vinylene carbonate, the mass percentage is 0.2%; the sulfur additive component is 1,3-propene sultone (PST), the mass percentage is 1%; the lithium salt component includes lithium difluoro(oxalato)borate and lithium hexafluorophosphate, the mass percentage of lithium difluoro(oxalato)borate is 0.8%, the mass percentage of lithium hexafluorophosphate is 15%, the rest is organic solvent component, the organic solvent component includes fluoroethylene carbonate, vinylene carbonate, dimethyl carbonate and methyl ethyl carbonate, wherein, calculated in terms of total mass of organic solvent component as 100%, the mass percentage of fluoroethylene carbonate is 3%, the mass percentage of vinylene carbonate is 19%, the mass percentage of dimethyl carbonate is 60%, the mass percentage of methyl ethyl carbonate is 18%.

[0041] The electrolyte is prepared by the following method: under argon atmosphere, lithium trifluoromethanesulfonate, fluoroethylene carbonate, vinylene carbonate, lithium difluoro(oxalato)borate and 1,3-propene sultone are added to the organic solvent component, and stirred and mixed at 10℃ for 5h to obtain the electrolyte.

[0042] Example 2

[0043] The difference between this example and example 1 is that the mass percentage of lithium trifluoromethanesulfonate and additive component A is adjusted by 1% on the basis of example 1, the organic solvent component used is used to replace lithium trifluoromethanesulfonate and additive component A in the electrolyte of example 1 in the same mass, and the other is the same as example 1.

[0044] Example 3

[0045] This example provides an electrolyte, which is different from example 1 only in that the additive component A in the electrolyte of example 1 is 2-methyl-2-phenyl malononitrile, and the other is the same as example 1, the chemical formula of additive component A is

[0046] Example 4

[0047] This example provides an electrolyte, which is identical to Example 1 except that the additive component A is 2-benzoyl malononitrile, and the chemical formula of the additive component A is

[0048]

[0049] Example 5

[0050] This example provides an electrolyte, which is identical to Example 1 except that the additive component A is 2,2,3,3-tetrafluoromalononitrile, and the chemical formula of the additive component A is

[0051]

[0052] Example 6

[0053] This example provides an electrolyte, which is identical to Example 1 except that the additive component A is 2-(3,4-difluorophenyl)malononitrile), and the chemical formula of the additive component A is

[0054]

[0055] Example 7

[0056] This example provides an electrolyte, which is identical to Example 1 except that the additive component A is pyridine-2,4-dicarbonitrile), and the chemical formula of the additive component A is

[0057]

[0058] Example 8

[0059] This example takes the electrolyte used in Example 1 as a reference, and takes the addition amount of the sulfur-based additive component included in the electrolyte as a variable. The difference from Example 1 is that the mass percentage of 1,3-propanesultone is adjusted to 0.5%, and the other is identical to Example 1.

[0060] Example 9

[0061] This example takes the electrolyte used in Example 1 as a reference, and takes the type and addition amount of the sulfur-based additive component included in the electrolyte as a variable. The difference from Example 1 is that 1,3-propanesultone is replaced by 1,3-propanesultone (1,3-PS), and the other is identical to Example 1.

[0062] Example 10

[0063] This example takes the electrolyte used in Example 1 as a reference, and takes the addition amount of the lithium salt component included in the electrolyte as a variable. The difference between this example and Example 1 is that the addition amount of lithium difluoro(oxalato)borate is adjusted to 0.5%, and the other conditions are the same as in Example 1.

[0064] Example 11

[0065] This example takes the electrolyte used in Example 1 as a reference, and takes the type and addition amount of the lithium salt component included in the electrolyte as a variable. The difference between this example and Example 1 is that lithium difluoro(oxalato)borate is replaced by lithium difluorophosphate, and the addition amount is 0.8%, and the other conditions are the same as in Example 1.

[0066] Comparative Example 1

[0067] This comparative example provides an electrolyte which is different from Example 1 only in that the comparative example does not contain lithium trifluoromethylsulfonate and additive component A, and the other conditions are the same as in Example 1.

[0068] Comparative Example 2

[0069] This comparative example provides an electrolyte which is different from Example 1 only in that the comparative example does not contain additive component A, and the other conditions are the same as in Example 1.

[0070] To further illustrate the beneficial effects of the present application, the above examples and comparative examples are assembled into batteries in the following manner and subjected to performance tests:

[0071] Graphite is used as the negative active material, and graphite, conductive agent acetylene black, binder carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR) are prepared into a negative electrode slurry in a mass ratio of 95.8:1.2:1.8:1.2, the negative electrode slurry is coated on a copper foil current collector, vacuum dried, and a negative electrode sheet is prepared; NCM523 is used as the positive active material, and the positive active material, conductive agent acetylene black, binder polyvinylidene fluoride (PVDF) are prepared into a positive electrode slurry in a mass ratio of 96.5:2.0:1.5, the positive electrode slurry is coated on an aluminum foil current collector, vacuum dried, and a positive electrode sheet is prepared; the electrolyte prepared in the above examples and comparative examples is assembled with the above positive electrode sheet, negative electrode sheet, and separator to form a 18650 battery, and the specific test results are shown in the following table:

[0072]

[0073]

[0074] It can be seen that, based on the test results of the test example, the lithium ion batteries assembled by the electrolyte prepared by applying implementation 1, implementation 2, implementation 3, implementation 4, implementation 5, implementation 6 and implementation 7 respectively can maintain a high capacity retention rate during high-temperature storage and maintain good capacity retention rate under high-rate discharge conditions. In the above experiments, the functional additives used in implementation 1, implementation 2, implementation 3, implementation 4, implementation 5, implementation 6 and implementation 7 all conform to the general structure of additive component A, and the structure containing o-fluorobenzoyl (strong electron-withdrawing) and dicyano in example 1 cooperates with lithium trifluoromethyl sulfonate to preferentially adsorb fluorine atoms on the positive electrode surface, and the ortho-fluorine directs the propionitrile group to chelate Ni 2+ , suppresses the release of lattice oxygen, and the content of lithium trifluoromethyl sulfonate and additive component A is increased in example 2, and the improvement effect is not obvious, indicating that the optimal additive ratio of the synergistic effect of lithium trifluoromethyl sulfonate and additive component A is shown in example 1; in example 3, the charge transfer complex of the phenyl π bond and the sulfonyl group improves the interface electron insulation and improves the rate discharge, and the dicyano contained in it complexes with the positive electrode transition metal ions and captures HF, improving the high-temperature storage performance. Example 4 contains conjugated benzoyl (high oxidation activity) plus dicyano, and benzoyl preferentially oxidizes to form a sulfonimide-poly-nitrile cross-linked film with -SO2- radicals decomposed by lithium trifluoromethyl sulfonate, and also contains cyanide, which inhibits the dissolution of transition metal ions and improves high-temperature performance; example 5 contains perfluoroalkyl chain (hydrophobic) plus dicyano, and -CF2-CF2- segment and -CF3 are separated by fluorine, forming a hydrophobic barrier layer at the electrode interface, and examples 6 and 7 both contain dicyano, which effectively improves the high-temperature storage performance.

[0075] Example 8 reduces the content of PST additive, and the high-temperature storage performance is slightly deteriorated, which may be due to the continuous consumption of PST during storage, and the consumed PST no longer functions; example 9 replaces the sulfur-based additive component PST with 1,3-PS to improve the rate discharge, which is because the initial DCR of PST is high, and the initial DCR of 1,3-PS is low, so the rate performance is improved;

[0076] Examples 10 and 11 reduce the content of lithium salt component and replace the type of lithium salt component, which has little effect on the rate performance and high-temperature performance, indicating that the lithium salt component has little effect on the rate and high-temperature storage performance in this formula.

[0077] To further prove the beneficial effects of the present application, the electrolyte prepared by example 1, example 2, and comparative example 1 is stored at 60°C for 40 days, and the stored electrolyte is tested by EIS under the same conditions, and the test results are shown in Table 1. Figure 1After high temperature storage, the impedance of example 1 and example 2 is lower than that of comparative example 1 and comparative example 2, which indicates that the synergistic effect of lithium triflate and additive component A can effectively improve the interface and reduce the interface impedance.

[0078] The electrolyte prepared in example 1 was subjected to linear scanning, see Figure 2 Compared with the common carbonate-based electrolyte, the electrochemical window is 4.3-4.4V, from Figure 2 It can be seen that after adding additive component A, the electrochemical window reaches 4.7V, which indicates that additive component A has strong antioxidant capacity.

[0079] In summary, the present application provides a lithium battery electrolyte additive, electrolyte and lithium battery, by utilizing the high oxidation stability of the anion in lithium triflate, inhibiting the oxidative decomposition of the electrolyte at high temperature, and utilizing the charge delocalization effect of lithium triflate to improve the lithium ion transfer number and reduce the concentration polarization; by the dicyano group of additive component A, it is preferentially complexed with the dissolved transition metal ions to form a dense interface film on the positive electrode surface, inhibits the side reaction, cooperates with lithium triflate to reduce the polarization voltage of the battery, improves the initial DCR, improves the rate discharge performance and high temperature storage performance, and improves the performance of lithium ion battery.

[0080] The above only describes the preferred embodiments of the present application, and does not use any limitation on the technical solutions of the present application, and those skilled in the art should understand that without departing from the spirit and principles of the present application, the technical solutions can also be subjected to several simple modifications and replacements, and these modifications and replacements also belong to the protection scope covered by the claims.

Claims

1. A lithium battery electrolyte additive, characterized by, The lithium triflate and the additive component A having a dicyano group are in a mass ratio of (0.5% to 1%):(0.5% to 1%).

2. The lithium battery electrolyte additive according to claim 1, characterized in that, The additive component A has a general formula of: wherein R is any one of a substituted or unsubstituted alkyl group having 2 to 6 carbon atoms, a substituted or unsubstituted phenyl group, a carbonyl group substituted with a phenyl group, and a pyridyl group.

3. The lithium battery electrolyte additive according to claim 1, wherein, The sulfur-based additive component, the carbonate-based additive component, and the lithium salt component are also included, and the mass ratio of the sulfur-based additive component, the carbonate-based additive component, and the lithium salt component to the lithium triflate is (0.5% to 1%):(0.5% to 1%):(0.5% to 1%):(0.5% to 1%).

4. The lithium battery electrolyte additive according to claim 3, characterized in that, The sulfur-based additive component includes one or both of 1,3-propane sultone and 1,3-propene sultone.

5. The lithium battery electrolyte additive according to claim 3, wherein, The carbonate-based additive component includes vinylene carbonate.

6. The lithium battery electrolyte additive according to claim 3, wherein, The lithium salt component includes lithium hexafluorophosphate.

7. The lithium battery electrolyte additive according to claim 6, wherein, The lithium salt component also includes one of lithium difluorophosphate and lithium difluoro oxalate borate.

8. An electrolyte, characterized by The lithium battery electrolyte additive of any one of claims 1-7, wherein the lithium triflate is in a mass concentration of 0.5% to 1% in the electrolyte.

9. The electrolyte of claim 8, wherein, The organic solvent component includes dimethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, and ethyl methyl carbonate, and the total mass of the fluorinated vinylene carbonate and the vinylene carbonate to the mass of the dimethyl carbonate and the ethyl methyl carbonate is in a mass ratio of (20 to 25):(2 to 70):(10 to 20).

10. A lithium battery, characterized by, The electrolyte of claim 8 or claim 9 or the lithium battery electrolyte additive of any one of claims 1-7.

Images