Electrolyte capable of synergistically improving fast charging performance and resisting high temperature and energy storage battery

Abstract

The invention provides an electrolyte capable of synergistically improving fast charge performance and high temperature resistance and an energy storage battery, the electrolyte comprises a lithium sulfonate compound additive A and a silazane additive B. The lithium sulfonate compound additive A improves DCR by improving ionic conductivity, and the silazane additive B inhibits corrosion of an HF positive electrode by removing HF, so that the electrolyte has high charge performance. And the dissolution of transition metal ions is reduced, so that the stability of the negative electrode SEI film is protected. The lithium sulfonate compound additive A is decomposed to provide a stable CEI base rich in LiF, the silazane additive B is decomposed to modify, fill and reinforce the film layer to form an ultra-stable and high-protective composite CEI film, and the electrolyte functional additive combination improves the physicochemical characteristics of the electrolyte and an electrode interface, so that the lithium sulfonate compound additive A and the silazane compound additive B are combined to form the composite CEI film. From the aspects of battery interface protection, side reaction reduction and electrolyte stability improvement, the problem of low capacity retention rate of the battery in a high-temperature environment is effectively improved on the premise of improving the fast charging performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium ion batteries, and relates to an electrolyte capable of improving fast charging performance and high-temperature resistance and an energy storage battery. BACKGROUND

[0002] Lithium ion batteries are widely used in aerospace, consumer electronics and other fields due to their high energy density, no memory effect, long cycle life and environmental friendliness. In the field of electric vehicles, lithium ion batteries as power sources directly affect the endurance and service life of vehicles. However, lithium ion batteries have many problems in high-temperature environments, and their high-temperature storage performance and cycle performance are key factors restricting their practical application.

[0003] At present, the commercialized electrolyte of lithium ion batteries mainly uses vinylene carbonate (VC) or fluoroethylene carbonate (FEC) as a film-forming additive. These additives can form a protective film on the electrode surface in the electrolyte, improving the high-temperature storage performance of the battery. However, these traditional film-forming additives have many shortcomings: VC or its oxidation / reduction products have poor high-pressure resistance and are prone to oxidative decomposition in polycrystalline high-voltage materials with large polarization, and the generated interface film structure is not stable; although FEC additives have good film-forming performance, they contain fluorine atoms in their molecular structure, which are prone to decomposition at high temperatures, and the decomposition process produces hydrogen fluoride (HF), which adversely affects the performance of the battery. In addition, existing electrolyte additives often cannot simultaneously consider the fast charging performance and high-temperature storage performance of the battery, and how to improve the fast charging performance of the battery while maintaining good high-temperature storage performance has become a key focus of current research.

[0004] In the practical application of lithium ion batteries, although researchers have provided various methods to eliminate water in the battery, there is still trace water that cannot be completely removed. In a high-temperature environment, these trace amounts of water can cause lithium salt decomposition to generate HF, which in turn corrodes the positive electrode material, resulting in reduced high-temperature storage performance of the battery. Therefore, developing an electrolyte additive combination that can simultaneously improve the fast charging performance and high-temperature storage performance of the battery while having good chemical stability is key to solving the current bottleneck in the development of lithium ion battery technology. SUMMARY

[0005] In view of the problems in the prior art that electrolyte additives decompose to produce HF in a high-temperature environment, causing corrosion of the positive electrode material, and the additive combination ratio is difficult to simultaneously consider the fast charging performance and high-temperature storage performance of the battery, the application provides an electrolyte capable of improving fast charging performance and high-temperature resistance and an energy storage battery.

[0006] The application is achieved by the following technical solutions:

[0007] An electrolyte capable of synergistically improving fast charging performance and high temperature resistance, comprising an electrolyte functional additive, an organic solvent and a lithium salt.

[0008] The electrolyte functional additive comprises lithium sulfonate compound additive A, silazane additive B, fluoroethylene carbonate, vinylene carbonate, lithium bisoxalate borate and 1,3-propylene sulfone lactone.

[0009] Preferably, the lithium sulfonate compound additive A has the general structure of:

[0010]

[0011] R1 is selected from any one of halogen, substituted or unsubstituted phenyl.

[0012] The lithium sulfonate compound additive A is selected from at least one of the following structural formulas, comprising:

[0013]

[0014] Preferably, the silazane additive B has the general structure of:

[0015]

[0016] R3, R4 and R5 are each independently selected from any one of hydrogen, substituted or unsubstituted alkyl with 1-5 carbon atoms, and substituted or unsubstituted alkenyl.

[0017] R6, R7 and R8 are each independently selected from any one of hydrogen, substituted or unsubstituted alkyl with 1-5 carbon atoms, and substituted or unsubstituted alkenyl.

[0018] Preferably, the organic solvent comprises methyl ethyl carbonate, ethylene carbonate and diethyl carbonate.

[0019] According to the total volume of the organic solvent being 100%, methyl ethyl carbonate accounts for 50-70%, ethylene carbonate accounts for 20-25%, and diethyl carbonate accounts for 10-20%.

[0020] Preferably, the mass percentage between the lithium sulfonate compound additive A, the silazane additive B, the fluoroethylene carbonate, the vinylene carbonate, the lithium bisoxalate borate and the 1,3-propylene sulfone lactone is 0.3%-0.5%: 0.2%-0.5%: 3-5%: 0.3-0.5%: 0.5-1%: 1-2%.

[0021] Preferably, the lithium salt comprises at least one of lithium hexafluorophosphate and lithium bisfluorosulfonimide.

[0022] Preferably, the concentration of the lithium salt in the electrolyte is 1.0-1.3 mol / L.

[0023] Preferably, the total amount of the electrolyte functional additive and the lithium salt is 6wt%-10wt% of the total amount of the electrolyte, and the rest is the organic solvent.

[0024] Under a nitrogen atmosphere, lithium sulfonate compound additive A, silazane additive B, fluoroethylene carbonate, vinylene carbonate, lithium bisoxalate borate and 1,3-propylene sultone and lithium salt are added to an organic solvent and stirred at 10 DEG C to obtain an electrolyte with synergistically improved fast charging performance and high temperature resistance.

[0025] An energy storage battery based on the electrolyte with synergistically improved fast charging performance and high temperature resistance is prepared based on the electrolyte with synergistically improved fast charging performance and high temperature resistance, and the electrolyte with synergistically improved fast charging performance and high temperature resistance, the positive electrode sheet, the negative electrode sheet and the separator are assembled into the energy storage battery.

[0026] Compared with the prior art, the present application has the following beneficial technical effects:

[0027] The present application provides an electrolyte with synergistically improved fast charging performance and high temperature resistance and an energy storage battery, the electrolyte comprising lithium sulfonate compound additive A and silazane additive B, the lithium sulfonate compound additive A being preferentially oxidized and decomposed at high voltage of the positive electrode, and the decomposition products (organic and inorganic matter containing F, S and O such as LiF, Li2SO3, Li2SO4, etc.) participating in the formation of the CEI film. The LiF component has high ionic conductivity, high mechanical strength and chemical stability, can reduce the initial DCR (total internal resistance under direct current) and the DCR increase in the fast charging cycle, and greatly improves the cycle performance, but the lithium sulfonate compound additive A decomposes HF at high temperature, corrodes the positive electrode interface, causes the dissolution of transition metal ions, and deteriorates the high temperature performance and causes crosstalk reaction. + The silazane additive B contains N-Si bond and is very active, especially highly sensitive to protonic acid (such as H + , HF), which can rapidly react with HF, protect the positive electrode material, significantly reduce the erosion (dissolution of transition metal ions Mn + / Co / Ni+) of the high-activity high-nickel positive electrode material by HF, inhibit the structure degradation (transition from layered structure to spinel or rock salt phase) of the positive electrode material and the dissolution of transition metal ions, reduce the damage of acid to the SEI film of the negative electrode and the CEI film of the positive electrode, and improve the compactness and uniformity of the film, and better block the contact of the electrolyte with the high-activity positive electrode material.

[0028] Further, the lithium sulfonate compound additive A improves the DCR by increasing the ionic conductivity, and the silazane additive B inhibits HF positive electrode corrosion by removing HF and reduces the dissolution of transition metal ions, thereby protecting the stability of the negative electrode solid electrolyte interface film (SEI) film. The two work synergistically: the lithium sulfonate compound additive A decomposes to provide a stable electrochemical interface CEI foundation rich in LiF, and the silazane additive B decomposes to modify, fill, and reinforce the film layer, forming an ultra-stable, high-protection composite CEI film. The electrolyte functional additive combination improves the capacity retention rate of the battery under high-temperature conditions by improving the physical and chemical properties of the electrolyte and electrode interface, protecting the battery interface, reducing side reactions, and improving the stability of the electrolyte, while improving the fast-charging performance. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described below. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0030] The present application provides a kind of electrolyte additive combination and its application lithium ion battery, electrolyte additive A is preferentially oxidized and decomposed under high voltage of positive electrode, and its decomposition product (F, S, O-containing organic matter and inorganic matter such as LiF, Li2 SO3, Li2 SO4 etc.) participates in the formation of CEI film.LiF component has high ionic conductivity, high mechanical strength and chemical stability, can reduce the initial DCR and the DCR growth in fast-charging cycle process, greatly improves the cycle performance, but additive A decomposes HF under high temperature, corrodes positive electrode interface and leads to transition metal ion dissolution, which deteriorates high-temperature performance, and causes cross-talk reaction.Silazane additive B contains N-Si bond, which is very active, especially highly sensitive to protonic acid (such as H + ,HF), it can quickly react with HF, protect the positive electrode material, significantly reduce the erosion (dissolve transition metal ions Mn + / Co + / Ni+) of HF to high-activity high-nickel positive electrode material, inhibit the structure degradation (layered structure to spinel or rock salt phase transition) of positive electrode material and the dissolution of transition metal ions. Reduce the damage of acid to negative SEI film and positive CEI film, improve the compactness and uniformity of the film, and better block the contact of electrolyte and high-activity positive electrode material.

[0031] The main purpose of the present application is to provide an electrolyte additive combination, an electrolyte and a lithium ion battery, which improves the fast-charging performance and solves the problem of low capacity retention rate caused by the increase of internal acidity of the battery under high-temperature conditions in the related art.

[0032] To achieve the above object, according to a first aspect of the present application, a functional additive for electrolyte is provided, which comprises a lithium sulfonate compound additive A, the general formula of the lithium sulfonate compound additive A is formula I:

[0033]

[0034] wherein R1 is selected from any one of halogen, substituted or unsubstituted phenyl.

[0035] Meanwhile, a silazane additive B is provided, the general formula of the silazane additive B is formula II:

[0036]

[0037] wherein R3, R4, R5 are each independently selected from any one of hydrogen, substituted or unsubstituted alkyl with carbon atom number of 1-5, substituted or unsubstituted alkenyl.

[0038] wherein R6, R7, R8 are each independently selected from any one of hydrogen, substituted or unsubstituted alkyl with carbon atom number of 1-5, substituted or unsubstituted alkenyl.

[0039] According to a second aspect of the present application, an electrolyte is provided, the electrolyte comprises an organic solvent, a lithium salt and an electrolyte additive (comprising the lithium sulfonate compound additive A and the silazane additive B), the electrolyte additive comprises the electrolyte additive as described in the first aspect.

[0040] The organic solvent comprises methyl ethyl carbonate, ethylene carbonate, diethyl carbonate. The organic solvent comprises, in terms of volume percentage, the following components: methyl ethyl carbonate 50-70%, ethylene carbonate 20-25% and diethyl carbonate 10-20%, based on the total volume of 100% of the organic solvent.

[0041] The electrolyte functional additive comprises fluoroethylene carbonate (3-5%), vinylene carbonate (0.2-0.5%), lithium bis(oxalato)borate (0.5-1%), 1,3-propylene sulfite (1-2%), lithium sulfonate compound additive A (0.3-0.5%) and silazane additive B (0.2-0.5%), all of which are added in the electrolyte in a mass percentage of 6-10%, and the rest is the organic solvent.

[0042] The lithium salt comprises at least one of lithium hexafluorophosphate and lithium bisfluorosulfonylimide.

[0043] The concentration of the lithium salt in the electrolyte is 1.0-1.3 mol / L.

[0044] The application provides a kind of energy storage battery, adopt graphite as negative active material, graphite, conductive agent acetylene black, binder CMC (sodium carboxymethyl cellulose), SBR (styrene-butadiene rubber) are prepared into negative electrode slurry according to the mass percentage of 95.4:1.5:1.4:1.7, negative electrode slurry is coated on copper foil current collector, vacuum drying, and negative electrode sheet is prepared;Adopt NCM622 (nickel cobalt manganese ternary material) as positive active material, positive active material, conductive agent acetylene black, binder PVDF (polyvinylidene fluoride) are prepared into positive electrode slurry according to the mass ratio of 96.5:2.2:1.3, positive electrode slurry is coated on aluminum foil current collector, vacuum drying, and positive electrode sheet is prepared;Respectively using the electrolyte prepared in the examples and comparative examples is assembled into soft package battery with the above positive electrode sheet, negative electrode sheet and diaphragm.

[0045] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0046] Example 1

[0047] The present embodiment provides a kind of electrolyte additive, the lithium sulfonate compound additive A is the compound (lithium fluorosulfonate) shown in formula I-1, fluoroethylene carbonate, vinylene carbonate, lithium bisoxalate borate, 1,3-propylene sulfonic acid lactone.

[0048]

[0049] The electrolyte is composed of organic solvent, lithium hexafluorophosphate and the above-mentioned electrolyte additive.

[0050] The organic solvent includes the following components in volume percentage, based on 100% of the total volume of organic solvent.

[0051] Methyl ethyl carbonate 65%, vinylene carbonate 20% and diethyl carbonate 15%.

[0052] The mass percentage of lithium sulfonate compound additive A (formula I-1) is 0.3%, the mass percentage of fluoroethylene carbonate is 3%, the mass percentage of vinylene carbonate is 0.3%, the mass percentage of lithium bisoxalate borate is 0.5%, and the mass percentage of 1,3-propylene sulfonic acid lactone is 1%, based on 100% of the total mass of electrolyte.

[0053] The concentration of lithium hexafluorophosphate in the electrolyte is 1.1 mol / L.

[0054] The electrolyte is prepared by the following method: under argon atmosphere, lithium fluorosulfonate, fluorinated ethylene carbonate, vinylene carbonate, lithium bis-oxalato-borate, 1,3-propane sultone and lithium hexafluorophosphate are stirred and mixed in an organic solvent formed by mixing methyl ethyl carbonate, ethylene carbonate and diethyl carbonate at a temperature of 10°C to obtain the electrolyte.

[0055] Example 2

[0056] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that the additive A (lithium fluorosulfonate) is added to the electrolyte in an amount of 0.5%, and the rest is the same as example 1.

[0057] Example 3

[0058] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that the functional additive has a structure as shown in formula I-2 (lithium trifluorosulfonate), and the addition amount is 0.3%, based on the total volume of the organic solvent being 100%, and the organic solvent includes the following components by volume percentage:

[0059] Methyl ethyl carbonate 70%, ethylene carbonate 20% and diethyl carbonate 10%.

[0060] The concentration of lithium bisfluorosulfonylimide in the electrolyte is 1.3 mol / L;

[0061] The rest is the same as example 1.

[0062]

[0063] Example 4

[0064] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that the functional additive has a structure as shown in formula I-2 (lithium trifluorosulfonate), and the addition amount is 0.5%, based on the total volume of the organic solvent being 100%, and the organic solvent includes the following components by volume percentage:

[0065] Methyl ethyl carbonate 70%, ethylene carbonate 20% and diethyl carbonate 10%.

[0066] The concentration of lithium bisfluorosulfonylimide in the electrolyte is 1.2 mol / L;

[0067] The rest is the same as example 1.

[0068] Example 5

[0069] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that on the basis of example 1, the addition of silazane additive B (formula II-1) (hexamethylenedi-silazane) is added, the addition amount is 0.2%, and the others are the same as example 1.

[0070]

[0071] Example 6

[0072] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that on the basis of example 1, 0.5% of silazane additive B (formula II-1) is added, and the others are the same as example 1.

[0073] Example 7

[0074] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that on the basis of example 1, silazane additive B (formula II-2) (1,3-dibutyl-1,1,3,3-tetramethylsilazane) is added, the addition amount is 0.5%, and the others are the same as example 1.

[0075]

[0076] Example 8

[0077] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that on the basis of example 1, silazane additive B (formula II-3) (1,1,3,3-tetramethyl-1,3-divinyl disilazane) is added, the addition amount is 0.5%, and the others are the same as example 1.

[0078]

[0079] Example 9

[0080] This example provides an electrolyte additive and electrolyte, which is different from example 1 only in that on the basis of example 1, silazane additive B (formula II-4) (tetramethyldisilazane) is added, the addition amount is 0.5%, and the others are the same as example 1.

[0081]

[0082] Example 10

[0083] This example provides an electrolyte additive and electrolyte, which is different from example 5 only in that the addition amount of fluorinated ethylene carbonate in the example is adjusted to 4%, and the others are the same as example 5.

[0084] Example 11

[0085] This example provides an electrolyte additive and electrolyte, which is different from example 5 only in that the amount of fluoroethylene carbonate added in the example is adjusted to 5%, and the others are the same as example 5.

[0086] Example 12

[0087] This example provides an electrolyte additive and electrolyte, which is different from example 5 only in that the amount of fluoroethylene carbonate added in the example is adjusted to 5%, and the others are the same as example 5.

[0088] Example 13

[0089] This example provides an electrolyte additive and electrolyte, which is different from example 5 only in that the amount of fluoroethylene carbonate added in the example is adjusted to 5%, and the others are the same as example 5.

[0090] Example 14

[0091] This example provides an electrolyte additive and electrolyte, which is different from example 5 only in that the amount of fluoroethylene carbonate added in the example is adjusted to 5%, and the others are the same as example 5.

[0092] Example 15

[0093] This example provides an electrolyte additive and electrolyte, which is different from example 5 only in that the amount of fluoroethylene carbonate added in the example is adjusted to 5%, and the others are the same as example 5.

[0094] Example 16

[0095] This example provides an electrolyte additive and electrolyte, which is different from example 5 only in that the amount of fluoroethylene carbonate added in the example is adjusted to 5%, and the others are the same as example 5.

[0096] Comparative example 1

[0097] This comparative example provides an electrolyte, which is different from example 1 only in that the comparative example does not contain lithium sulfonate compound additive A, and the others are the same as example 1

[0098]

[0099]

[0100] Example 1, Example 2, Example 3, Example 4 vs. Comparative Example 1 Additive A (lithium fluorosulfonate, lithium trifluorosulfonate) is added. Lithium fluorosulfonate, lithium trifluorosulfonate reacts with water in the battery to generate lithium sulfate and lithium fluoride, and the main effect is on the negative electrode, reducing DCR, thereby improving fast charging cycles, but lithium fluorosulfonate, lithium trifluorosulfonate generates HF at high temperature, corrodes the positive electrode interface, causes transition metal ions to dissolve out, and slightly worsens high-temperature storage performance;

[0101] Example 5, Example 6, Example 7, Example 8, Example 9 Additive B (silazane) is added on the basis of Example 1. The two synergistically improve fast charging and high-temperature storage performance.

[0102] Example 5, Example 6 Mechanism of action: The strong Lewis base property of methylene bisilazane in Example 6 allows it to quickly capture HF and block the LiPF6 hydrolysis chain reaction. Its oxidation products (such as Li3N, Li2O) react with lithium fluorosulfonate to form LiF / Li2SO4 inorganic-organic hybrid CEI, which has high ionic conductivity and mechanical strength.

[0103] Example 7 Mechanism of action: The hydrophobicity of butyl reduces the hygroscopicity of the electrolyte, slowing down the generation rate of HF. The large steric hindrance allows it to decompose slowly, and the CEI repair ability is persistent, reducing the interface reconstruction energy consumption during storage.

[0104] Example 8 Mechanism of action: The vinyl group undergoes free radical polymerization under high pressure at the positive electrode, generating a three-dimensional network CEI that effectively buffers the lattice stress of high-nickel materials during charging and discharging, while also improving the lithium ion diffusion rate at the interface.

[0105] Example 9 Mechanism of action: High reactivity allows it to efficiently remove acid in small amounts, and synergistically improves fast charging and high-temperature performance with lithium fluorosulfonate.

[0106] Example 10 and Example 11 Increase the amount of fluoroethylene carbonate added. Compared with Example 5, there is little effect on fast charging and high-temperature performance;

[0107] Example 12 Increase the amount of vinylene carbonate added. Compared with Example 5, fast charging is slightly worsened, and the possible reason is that too much vinylene carbonate increases DCR, leading to a high DCR growth rate during fast charging, which worsens fast charging cycles. Therefore, the optimal amount of lithium bis(oxalato)borate is 0.5%.

[0108] Example 13, Example 14 Increase the amount of lithium bis(oxalato)borate added. Compared with Example 5, fast charging performance is slightly worsened, and the main reason is that too much lithium bis(oxalato)borate increases the initial DCR, leading to a high DCR growth rate during fast charging, which worsens fast charging cycles. Therefore, the optimal amount of lithium bis(oxalato)borate is 0.5%.

[0109] Example 15, Example 16 increases 1,3-propylene sulfone lactone additive amount, the influence on fast charging and high temperature performance is little.

[0110] melting point boiling point density formula i-1 / 234℃ 1.33 g / cm 3 ]] formula i-2 300℃ / 1.90 g / cm 3 ]] formula ii-1 -78℃ 125℃ 0.774 g / cm 3 ]] formula ii-2 47℃ 251.3℃ 0.8 g / cm 3 ]] formula ii-3 0℃ 161℃ 0.819 g / cm 3 ]] formula ii-4 99℃ 91.1℃ 0.752 g / cm 3 ]]

[0111] The lithium sulfonate compound additive A introduced in the application is preferentially oxidized and decomposed under high pressure of the positive electrode, generates F, S, O-containing organic and inorganic substances, and participates in the formation of the CEI film. The CEI film has good chemical stability and mechanical strength, can effectively reduce the initial DCR and the DCR increase in the fast charging cycle process, and significantly improves the cycle performance of the battery;

[0112] The silazane additive B of the application contains N-Si bond, has high proton acid sensitivity, can rapidly react with HF, and effectively protects the positive electrode material. By inhibiting the dissolution of transition metal ions Mn + / Co + / Ni + , reduces the damage of acid to the negative SEI film and the positive CEI film, improves the compactness and uniformity of the film, and effectively blocks the contact of electrolyte with the high-activity positive electrode material;

[0113] The electrolyte additive combination of the application is reasonably designed, and the components synergize to improve the fast charging performance of the battery while maintaining good high-temperature storage performance. By optimizing the ratio of each additive (especially the ratio of A and B), the overall performance of the battery is improved;

[0114] The electrolyte additive of the application has good chemical stability and can maintain a stable state during battery use, avoiding the corrosion of harmful substances generated by decomposition under high temperature environment to the electrode material, effectively solving the problem of corrosion of the positive electrode material caused by the decomposition of the electrolyte additive under high temperature in the prior art;

[0115] The electrolyte additive combination of the application can effectively inhibit the structural degradation of the positive electrode material (such as the transition from layered structure to spinel or rock salt phase), improve the stability of the electrode material, and prolong the service life of the battery.

[0116] In the application, all the embodiments and preferred implementation methods mentioned in the text can be combined to form new technical solutions if not otherwise specified.

[0117] In the application, all the technical features and preferred features mentioned in the text can be combined to form new technical solutions if not otherwise specified.

[0118] In the application, percentage (%) or part refers to the weight percentage or weight part of the composition if not otherwise specified.

[0119] In the present application, unless otherwise specified, each component or preferred component thereof involved can be combined with each other to form a new technical solution.

[0120] In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand notation for any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "6~22" represents that all real numbers between "6~22" have been listed herein, and "6~22" is only a shorthand notation for these numerical combinations.

[0121] The lower limit and upper limit of the "range" disclosed in the present application can be one or more lower limits, and one or more upper limits, respectively.

[0122] In the present application, the term "and / or" used herein means any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0123] In the present application, unless otherwise specified, each reaction or operation step can be carried out sequentially or according to the sequence. Preferably, the reaction method herein is carried out sequentially.

[0124] Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to that described can also be applied in the present application.

[0125] It should be understood that when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or collections thereof.

[0126] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0127] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form; any person skilled in the art can easily implement the present application according to the description and the above description; however, any person skilled in the art can make some changes, modifications and equivalent changes within the scope of the technical solutions of the present application, and the equivalent embodiments of the present application are still within the protection scope of the technical solutions of the present application.

Claims

1. An electrolyte synergistically improving fast-charging performance and high-temperature resistance, characterized in that, The electrolyte functional additive includes a lithium sulfonate compound additive A, a silazane additive B, fluoroethylene carbonate, vinylene carbonate, lithium bisoxalate borate and 1,3-propylene sulfone lactone. The electrolyte functional additive includes a lithium sulfonate compound additive A, a silazane additive B, fluoroethylene carbonate, vinylene carbonate, lithium bisoxalate borate and 1,3-propylene sulfone lactone. 2.The electrolyte according to claim 1, characterized in that, The lithium sulfonate compound additive A has a general structure formula as follows: R1 is selected from any one of halogen, substituted or unsubstituted phenyl. 3.The electrolyte of claim 1, wherein, The lithium sulfonate compound additive A is selected from at least one of the following structural formulas, including: 4.The electrolyte of claim 1, wherein, The silazane additive B has a general structure formula as follows: R3, R4 and R5 are each selected from any one of hydrogen, substituted or unsubstituted alkyl with 1-5 carbon atoms, and substituted or unsubstituted alkenyl. R6, R7 and R8 are each selected from any one of hydrogen, substituted or unsubstituted alkyl with 1-5 carbon atoms, and substituted or unsubstituted alkenyl. 5.The electrolyte of claim 1, wherein the electrolyte is capable of improving the fast-charging performance and the high-temperature resistance in a synergistic manner. The organic solvent includes methyl ethyl carbonate, ethylene carbonate and diethyl carbonate. According to 100% of the total volume of the organic solvent, methyl ethyl carbonate accounts for 50-70%, ethylene carbonate accounts for 20-25%, and diethyl carbonate accounts for 10-20%. 6.The electrolyte of claim 1, wherein the electrolyte is a synergistically improved electrolyte for improving fast charging performance and high temperature resistance. The mass ratio between the lithium sulfonate compound additive A, the silazane additive B, fluoroethylene carbonate, vinylene carbonate, lithium bisoxalate borate and 1,3-propylene sulfone lactone is 0.3%-0.5%:0.2%-0.5%:3-5%:0.3-0.5%:0.5-1%:1-2%. 7.The electrolyte of claim 1, wherein the electrolyte is characterized by, The lithium salt includes at least one of lithium hexafluorophosphate and lithium bisfluorosulfonimide, and the concentration of the lithium salt in the electrolyte is 1.0-1.3 mol / L. 8.The electrolyte according to claim 1, characterized in that, The sum of the added amounts of the electrolyte functional additive and the lithium salt accounts for 6wt%-10wt% of the total amount of the electrolyte, and the rest is the organic solvent.

9. The preparation method of the electrolyte for synergistically improving fast-charging performance and high-temperature resistance according to claim 1, characterized in that, The electrolyte includes, The lithium sulfonate compound additive A, the silazane additive B, fluoroethylene carbonate, vinylene carbonate, lithium bisoxalate borate and 1,3-propylene sulfone lactone and the lithium salt are added to the organic solvent under a nitrogen atmosphere, and are stirred and mixed at 10°C to obtain the electrolyte with synergistically improved fast charging performance and high temperature resistance.

10. An energy storage battery based on the electrolyte for improving fast charging performance and high temperature resistance, prepared based on the electrolyte for improving fast charging performance and high temperature resistance according to any one of claims 1-8, characterized in that, The electrolyte with synergistically improved fast charging performance and high temperature resistance is used to assemble an energy storage battery together with a positive electrode sheet, a negative electrode sheet and a separator.

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