Electrolyte, battery, battery pack and electric equipment

Abstract

The invention provides an electrolyte, a battery, a battery pack and electric equipment, the electrolyte comprises an additive, and the additive comprises a fluorocarbonate compound and a nitro organic compound. According to the electrolyte disclosed by the invention, by introducing the specific additive, a decomposition product can be induced to form a thin and compact solid electrolyte interface film with good lithium ion conduction capability, so that the rate capability and the cycling stability of the battery are improved at the same time.

Description

Technical Field

[0001] The present invention relates to an electrolyte, in particular to an electrolyte, a battery and an electrical device, belonging to the field of secondary batteries. Background Art

[0002] Lithium-ion batteries have been widely used in mobile phones, laptops, electric vehicles and other fields due to their advantages such as high energy density, long cycle life and low self-discharge. Electrolyte, as an important component of lithium-ion batteries, has an important impact on the performance of lithium-ion batteries.

[0003] Adding fluorinated ether diluents to the electrolyte has a positive effect on improving the battery's operating voltage window, cyclability, and safety. However, with the improvement of production levels and the growing demand for energy, endurance, and high power output, there is a need to seek electrolytes with better rate performance and stability. However, fluorinated ether diluents easily decompose at the battery's negative electrode interface to form a solid electrolyte interface film (SEI). This solid electrolyte interface film has the defects of high impedance and high lithium ion transmission energy barrier, which is not conducive to the battery's rate performance. Summary of the Invention

[0004] The present invention provides an electrolyte, which can simultaneously improve the rate capability and cycle stability of a battery.

[0005] The present invention also provides a battery. Since the battery includes the above electrolyte, the battery has the advantages of low impedance and long cycle time.

[0006] The present invention also provides a battery pack. Since the battery pack includes at least two of the above batteries, the battery pack has the advantages of high rate and long cycle.

[0007] The present invention also provides an electrical device, which includes the battery and has good electrochemical performance and a long service life.

[0008] In a first aspect, the present invention provides an electrolyte comprising an additive, wherein the additive comprises a fluorinated carbonate compound and a nitro organic compound.

[0009] Optionally, the fluorinated carbonate compound includes a compound represented by Formula 1 and / or a compound represented by Formula 2:

[0010] Formula 1,

[0011] Formula 2,

[0012] Wherein, R1 and R2 are each independently any one of a fluorine-substituted or unsubstituted C1-C20 alkyl group, a fluorine-substituted or unsubstituted C2-C20 alkenyl group, and at least one of R1 and R2 includes a fluorine substituent; R3 and R4 are each independently any one of a fluorine-substituted or unsubstituted C1-C20 alkyl group, a fluorine-substituted or unsubstituted C2-C20 alkenyl group, and a fluorine group, and at least one of R3 and R4 includes a fluorine atom.

[0013] Optionally, the nitro organic compound includes a compound represented by Formula 3:

[0014] Formula 3,

[0015] Wherein, R4 to R9 are each independently any one of nitro, H, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted alkenyl, and at least one of R4 to R9 is nitro.

[0016] Optionally, the fluorocarbonate compound includes one or more of methyl trifluoroethyl carbonate, ethyl trifluoroethyl carbonate, di(2-fluoroethyl) carbonate, bis(2,2,2)-trifluoroethyl carbonate, trifluoropropylene carbonate, difluoropropylene carbonate, fluoroethylene carbonate, and difluoroethylene carbonate.

[0017] Optionally, the nitro organic compound includes one or more of: 3-nitrophthalonitrile, 4-nitrophthalonitrile, o-nitrobenzonitrile, m-nitrobenzonitrile, p-nitrobenzonitrile, 3,5-dinitrobenzonitrile, 4-methyl-3-nitrobenzonitrile, 2-methoxy-5-nitrobenzonitrile, 4-methoxy-2-nitrobenzonitrile, 2-amino-5-nitrobenzonitrile, o-nitrophenylacetonitrile, m-nitrophenylacetonitrile, p-nitrophenylacetonitrile, and 4-nitrobenzoylacetonitrile.

[0018] Optionally, the volume percentage of the fluorinated carbonate compound in the total volume of the electrolyte is 1-5%;

[0019] And / or, the electrolyte further comprises an electrolyte salt, and the molar percentage of the nitro organic compound in the electrolyte salt is 0.2-10%.

[0020] Optionally, the electrolyte includes a fluorine-containing lithium salt, an ether solvent and a fluorine-containing ether diluent.

[0021] Optionally, the fluorine-containing lithium salt includes one or more of lithium bis(fluorosulfonyl)imide, lithium trifluoromethylsulfonyl imide, lithium bis(fluorooxalatoborate), and lithium difluorophosphate;

[0022] And / or, the ether solvent includes one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and 1,3-dioxolane;

[0023] And / or, the fluorine-containing ether diluent includes one or more of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 2,2,2-trifluoroethyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,3,3,3-pentafluoropropyl-2,2,2-trifluoroethyl ether, dichloromethane, dichlorobutane, and trifluoromethoxybenzene.

[0024] Optionally, the molar concentration of the fluorine-containing lithium salt in the electrolyte is 2-5 mol·L -1 ;

[0025] And / or, the volume ratio of the ether solvent to the fluorinated ether diluent is 1:(1-6).

[0026] In a second aspect, the present invention provides a battery comprising the electrolyte described in the first aspect.

[0027] In a third aspect, the present invention provides a battery pack comprising at least two batteries according to the second aspect.

[0028] In a fourth aspect, the present invention provides an electrical device comprising the battery described in the second aspect or the battery pack described in the third aspect.

[0029] The electrolyte provided by the present invention can induce the decomposition products to form a thin and dense solid electrolyte interface film with good lithium ion conductivity by introducing specific additives, thereby improving the battery's rate capability and cycle stability. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0031] Throughout this application, references to "one embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment, embodiment, or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and / or subcombinations in one or more embodiments or examples.

[0032] Introducing fluoroether diluents and high-concentration fluorinated lithium salts into the electrolyte can form localized high lithium salt concentration areas on the electrode surface or in specific areas. Such areas have a positive effect on improving the battery's operating voltage window and cycle stability. However, fluoroether diluents and fluorinated lithium salts are prone to decomposition during battery use. On the one hand, they decompose in a short period of time and produce a large amount of fluorinated compounds. These fluorinated compounds will form a solid electrolyte interface film on the negative electrode surface with high impedance, high lithium ion transfer energy barrier, and unevenness, limiting the application of the electrolyte in high-rate scenarios. On the other hand, as the battery is used, the fluoroether diluent gradually decomposes completely, causing the high lithium salt concentration area to fail.

[0033] To solve the above problems, the present invention provides the following solutions:

[0034] In a first aspect, the present invention provides an electrolyte comprising: a fluorocarbonate compound and a nitro organic compound.

[0035] In the present invention, by introducing fluorinated carbonate compounds and nitro organic compounds into the electrolyte, the rate capability and cycle stability of the battery can be effectively improved. The main reasons include: the introduction of fluorinated carbonate compounds into the electrolyte will affect the solvation structure of the electrolyte system, replace the decomposition of other fluorinated reagents, and induce their decomposition products to deposit uniformly at the electrode interface, reducing the proportion of fluorinated compounds in the solid electrolyte interface film, while promoting the decomposition products to form a thin and dense solid electrolyte interface film. At the same time, nitro organic compounds will also be better than other solvents in undergoing redox reactions at the solid-liquid interface. The decomposition products also participate in the formation of the electrode solid electrolyte interface film and help increase the proportion of N-containing inorganic phases in the solid electrolyte interface film, thereby enhancing the lithium ion conductivity and mechanical strength of the interface film and helping to reduce interface side reactions. In addition, the organic nitro additive can also react with trace water and hydrofluoric acid in the electrolyte, thereby alleviating the damage of water and hydrofluoric acid to the battery system.

[0036] Based on the above reasons, the electrolyte of the present invention can improve the rate capability and cycle stability of the battery by regulating the decomposition order of the components and inducing the decomposition products to form a thin and dense solid electrolyte interface film with good lithium ion conductivity.

[0037] It should be noted that the above-mentioned electrolyte of the invention has universal applicability and can be used not only in lithium-ion battery systems, but also in sodium-ion batteries, zinc-ion batteries and other systems.

[0038] When it is used in a lithium-ion battery system, fluoroether diluents and fluorine-containing lithium salts can be further introduced to form a local high lithium salt concentration area on the electrode surface or in a specific area, thereby improving the lithium ion transport at the electrode / electrolyte interface. At the same time, since the fluorocarbonate compounds and nitro organic compounds synergistically replace the decomposition of the fluoroether diluent, the above-mentioned high lithium salt concentration area can be kept stable, thereby improving the battery's rate capability and cycle stability.

[0039] In one embodiment, the fluorinated carbonate compound includes a compound represented by Formula 1 and / or a compound represented by Formula 2:

[0040] Formula 1,

[0041] Formula 2,

[0042] wherein R1 and R2 are each independently any one of a fluorine-substituted or unsubstituted C1-C20 alkyl group, a fluorine-substituted or unsubstituted C2-C20 alkenyl group, and at least one of R1 and R2 includes a fluorine substituent; and R3 and R4 are each independently any one of a fluorine-substituted or unsubstituted C1-C20 alkyl group, a fluorine-substituted or unsubstituted C2-C20 alkenyl group, and a fluorine group, and at least one of R3 and R4 includes a fluorine atom.

[0043] The fluorinated carbonate compounds with the structure described above can not only affect the solvation structure of the electrolyte system, replace the decomposition of other fluorinated reagents, and induce their decomposition products to be uniformly deposited at the electrode interface, promoting the formation of a thin and dense solid electrolyte interface film by the decomposition products, but also maintain good solubility in a variety of solvents, thereby ensuring the consistency of the electrolyte.

[0044] In some embodiments, the C1-C20 alkyl group may be a C1-C20 straight-chain alkyl group or a C3-C20 straight-chain alkyl group.

[0045] In one embodiment, the nitro organic compound includes a compound represented by Formula 3:

[0046] Formula 3,

[0047] Wherein, R4 to R9 are each independently any one of nitro, H, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted alkenyl, and at least one of R4 to R9 is nitro.

[0048] Nitro-organic compounds with the aforementioned structure maintain good solubility in a variety of solvents, thereby ensuring the consistency of the electrolyte. Furthermore, as additives, they readily decompose during the battery charge and discharge process, participating in the formation of the SEI and thus regulating the SEI composition.

[0049] In some embodiments, the C1-C20 alkyl group may be a C1-C20 straight-chain alkyl group or a C3-C20 straight-chain alkyl group.

[0050] In some embodiments, at least one of R4 to R9 is a cyano group. When at least one of R4 to R9 is a cyano group, the cyano group and the nitro group can jointly increase the proportion of the N-containing inorganic phase in the solid electrolyte interface film (such as Li3N, LiN x O y The cyanide group has a strong binding ability with water and HF, which can alleviate the damage of HF in the battery to the battery system.

[0051] In a specific embodiment, the fluorocarbonate compound includes one or more of methyl trifluoroethyl carbonate, ethyl trifluoroethyl carbonate, di(2-fluoroethyl) carbonate, bis(2,2,2)-trifluoroethyl carbonate, trifluoropropylene carbonate, difluoropropylene carbonate, fluoroethylene carbonate, and difluoroethylene carbonate.

[0052] The fluorinated carbonate compounds described above not only ensure that they can replace the decomposition of other fluorinated reagents and induce and promote the formation of a thin and dense solid electrolyte interface film from the decomposition products, but also have the advantage of being cheap and readily available, which can further reduce the cost of the electrolyte.

[0053] In a specific embodiment, the nitro organic compound includes: one or more of 3-nitrophthalonitrile, 4-nitrophthalonitrile, o-nitrobenzonitrile, m-nitrobenzonitrile, p-nitrobenzonitrile, 3,5-dinitrobenzonitrile, 4-methyl-3-nitrobenzonitrile, 2-methoxy-5-nitrobenzonitrile, 4-methoxy-2-nitrobenzonitrile, 2-amino-5-nitrobenzonitrile, o-nitrophenylacetonitrile, m-nitrophenylacetonitrile, p-nitrophenylacetonitrile, and 4-nitrobenzoylacetonitrile.

[0054] The nitro organic compound described above can further enhance the lithium ion conductivity and mechanical strength of the solid electrolyte interface membrane, and also has the advantage of being cheap and readily available, which can further reduce the cost of the electrolyte.

[0055] In a specific embodiment, the volume percentage of the fluorinated carbonate compound in the total volume of the electrolyte is 1-5%.

[0056] In a specific embodiment, the electrolyte further includes an electrolyte salt, and the molar percentage of the nitro organic compound in the electrolyte salt is 0.2-10%.

[0057] The addition amount of the fluorocarbonate compound as described above can further ensure that the overall viscosity of the electrolyte is low and avoid changing the properties of the SEI layer, making it too thick or uneven.

[0058] The addition amount of the nitro organic compound as described above can further enhance the lithium ion conductivity and mechanical strength of the solid electrolyte interface membrane while avoiding unnecessary side reactions with the electrode material.

[0059] In a specific embodiment, the electrolyte further comprises a fluorine-containing lithium salt, an ether solvent and a fluorine-containing ether diluent.

[0060] In the embodiment described above, the introduction of ether solvents and fluorinated ether diluents into the electrolyte can form a local high lithium salt concentration area on the electrode surface or in a specific area, further improving the lithium ion transport at the electrode / electrolyte interface. At the same time, since the fluorinated carbonate compounds and nitro organic compounds synergistically replace the decomposition of the fluorinated ether diluent, the above-mentioned high lithium salt concentration area can be kept stable, thereby further improving the battery's rate capability and cycle stability.

[0061] It can be understood that the above-mentioned fluorine-containing lithium salt is an electrolyte salt.

[0062] In a specific embodiment, the fluorine-containing lithium salt includes one or more of lithium bis(fluorosulfonyl)imide, lithium trifluoromethylsulfonylimide, lithium bis(fluorooxalatoborate), and lithium difluorophosphate.

[0063] And / or, the ether solvent includes one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and 1,3-dioxolane.

[0064] And / or, the fluorine-containing ether diluent includes one or more of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 2,2,2-trifluoroethyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,3,3,3-pentafluoropropyl-2,2,2-trifluoroethyl ether, dichloromethane, dichlorobutane, and trifluoromethoxybenzene.

[0065] The fluorinated lithium salts, ether solvents, and fluorinated ether diluents described above have the advantages of being inexpensive and readily available, and the electrolyte containing the above components can form a local high lithium salt concentration area on the electrode surface or in a specific area, further improving the lithium ion transport at the electrode / electrolyte interface.

[0066] In one embodiment, the molar concentration of the fluorine-containing lithium salt in the electrolyte is 2-5 mol·L-1 ;

[0067] And / or, the volume ratio of the ether solvent to the fluorinated ether diluent is 1:(1-6).

[0068] The electrolyte described above can further improve lithium ion transport at the electrode / electrolyte interface while ensuring low viscosity of the electrolyte.

[0069] For example, the molar concentration of the fluorine-containing lithium salt in the electrolyte is 2.0 mol·L -1 , 2.5 mol·L -1 、3.0 mol·L -1 、3.5 mol·L -1 , 4.0 mol·L -1 , 4.5 mol·L -1 , 5.0 mol·L -1 Any value or a range consisting of both.

[0070] The volume ratio of the ether solvent to the fluorinated ether diluent is any ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, etc.

[0071] In a second aspect, the present invention provides a battery comprising the electrolyte described in the first aspect.

[0072] Due to the inclusion of the above electrolyte, the battery has excellent cycle performance and rate performance.

[0073] In one embodiment, in addition to the electrolyte provided by the present invention, the battery also includes a positive electrode sheet, a negative electrode sheet, and a separator. During the battery's charge and discharge process, active metal ions are intercalated and released between the positive and negative electrodes, and the electrolyte acts as an ion conductor between the positive and negative electrodes. The separator is disposed between the positive and negative electrodes, primarily preventing short circuits between the positive and negative electrodes while allowing ions to pass through.

[0074] This application does not limit the type of separator; any separator material used in existing batteries can be used. Examples include, but are not limited to, single-layer PP (polypropylene) film, single-layer PE (polyethylene) film, double-layer PP / PE, double-layer PP / PP, and triple-layer PP / PE / PP separators.

[0075] Exemplarily, the positive electrode sheet includes a positive electrode active material, which includes but is not limited to: LiCoO2, LiMn2O4, LiMnO2, Li2MnO4, LiFePO4, Li 1+a Mn 1-b M b O2、LiCo1-b M b O2、LiFe 1-b M b PO4, Li2Mn 1-b O4、LiNi x Co y Mn z At least one of O2, etc., M is selected from one or more of Ni, Co, Mn, Al, Cr, Mg, Zr, Mo, V, Ti, B, F, 0≤a<0.2, 0≤b<1, x+y+z=1.

[0076] Illustratively, the negative electrode sheet includes a negative electrode material. The negative electrode material can be a conventional material in the art, including but not limited to one or more of a carbonaceous material, a silicon-carbon material, an alloy material, and a lithium-containing metal composite oxide. Furthermore, the negative electrode material is one or more of graphite, soft carbon, hard carbon, silicon, a silicon-oxygen compound, a silicon-carbon composite, and lithium titanate.

[0077] Illustratively, the above-mentioned battery can be prepared by a method comprising the following processes: stacking the above-mentioned positive electrode sheet, separator and negative electrode sheet in sequence to obtain a battery cell or stacking the above-mentioned positive electrode sheet, separator and negative electrode sheet in sequence and then winding them to obtain a battery cell; placing the battery cell in a packaging battery film shell (such as an aluminum-plastic film shell), injecting electrolyte into the outer packaging and sealing it to prepare the battery of the present invention.

[0078] In a third aspect, the present invention provides a battery pack comprising at least two batteries according to the second aspect.

[0079] Generally, a battery pack includes at least two of the above-mentioned batteries, which are connected as single cells to form a battery pack. These batteries can be electrically connected using conventional methods in the art, such as series connection, parallel connection, or a combination of these connection methods.

[0080] In a fourth aspect, the present invention provides an electrical device comprising the battery described in the second aspect or the battery pack described in the third aspect.

[0081] The electrical equipment in the embodiments of the present invention can be conventional electrical equipment in the field, such as power equipment (such as electric vehicles, electric cars), electronic equipment (such as mobile phones, tablets, laptops, digital cameras, etc.), wearable devices (such as watches, bracelets, VR glasses, etc.), energy storage power stations, etc., without special restrictions.

[0082] The technical solutions of the present invention are further illustrated below with reference to specific examples. All parts, percentages, and ratios described in the following examples are based on weight. All reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment. The instruments used in the examples are commercially available.

[0083] Example 1

[0084] This example provides an electrolyte solution including additives: 3-nitrophthalonitrile, methyl trifluoroethyl carbonate;

[0085] The preparation method comprises the following steps:

[0086] (1) 1 mol of battery-grade lithium bis(fluorocarbonyl)sulfonate, 0.05 mol of 3-nitrophthalonitrile, and 250 ml of ethylene glycol dimethyl ether containing 6% methyl trifluoroethyl carbonate were mixed and dissolved by vigorous stirring to form a transparent and uniform high-concentration electrolyte; the solvent was dried over molecular sieves to a moisture content of less than 20 ppm before use.

[0087] (2) Add 750 ml of anhydrous 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether diluent to the above high-concentration electrolyte and stir evenly to obtain an electrolyte.

[0088] Example 2

[0089] The only difference from Example 1 is that 3-nitrophthalonitrile is replaced by 2-methoxy-5-nitrobenzonitrile.

[0090] Example 3

[0091] The only difference from Example 1 is that 0.05 mol of 3-nitrophthalonitrile is replaced by 0.08 mol of 3-nitrophthalonitrile.

[0092] Examples 4-10

[0093] The only difference from Example 1 is that the content of the additives is changed, as shown in Table 1.

[0094] Comparative Example 1

[0095] The preparation method of the electrolyte in this example comprises the following steps:

[0096] (1) dissolving battery-grade lithium bis(fluorosulfonyl)imide in anhydrous 1,2-dimethoxyethane solvent by vigorous stirring to form a transparent and uniform high-concentration electrolyte solution, thereby obtaining a solution with a lithium salt concentration of 4 M;

[0097] (2) Adding 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether diluent to the high-entropy high-concentration electrolyte, wherein the volume ratio of the solvent to the diluent is 1:3, and stirring evenly to obtain an electrolyte.

[0098] Comparative Examples 2-3

[0099] The only difference from Example 1 is that the content of the additives is changed, as shown in Table 1.

[0100] Test example

[0101] The preparation of NCM|Li half-cell using the above electrolyte includes the following steps:

[0102] Preparation of positive electrode: take NCM622 positive electrode powder (molecular formula LiNi 0.6 Mn 0.2 Co 0.2 O2), conductive carbon black, polyvinylidene fluoride (PVDF) and N-methyl pyrrolidone, PVDF was added to N-methyl pyrrolidone, stirred evenly, and then conductive carbon black was added. After stirring evenly again, NCM622 was added in batches. After stirring evenly, the slurry was scraped onto aluminum foil, vacuum dried at 90℃ for 6h, and punched into discs with a diameter of 14mm;

[0103] Assemble the battery: Assemble the positive electrode sheet, polypropylene separator, and metal lithium sheet into a button battery in order, and add an appropriate amount of the electrolyte obtained in each embodiment and comparative example.

[0104] The following performances of NCM|Li half-cells were tested:

[0105] The NCM|Li half-cells of the embodiment and comparative example were first subjected to three cycles of 0.1C / 0.1C low current charge and discharge in a battery testing system to form a stable SEI film. Then, their rate and cycle capabilities were tested in the 3-4.5V window. The discharge rates of the rate test were 0.2C, 0.5C, 1C, and 2C, respectively, and the number of cycles in the cycle test was 100 cycles (0.5C). The test results are shown in Table 1.

[0106] The above test results are summarized in Table 1.

[0107] Table 1:

[0108]

[0109] It can be seen from Table 1 that, compared with the comparative example, the electrolyte of the embodiment can significantly improve the cycle performance and rate performance of the battery when used in the battery.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrolyte, characterized in that The invention comprises additives, wherein the additives include fluorinated carbonate compounds and nitro organic compounds.

2. The electrolyte according to claim 1, characterized in that The fluorinated carbonate compounds include compounds represented by Formula 1 and / or compounds represented by Formula 2: Formula 1, Formula 2, wherein R1 and R2 are each independently any one of a fluorine-substituted or unsubstituted C1-C20 alkyl group, a fluorine-substituted or unsubstituted C2-C20 alkenyl group, and at least one of R1 and R2 includes a fluorine substituent; and R3 and R4 are each independently any one of a fluorine-substituted or unsubstituted C1-C20 alkyl group, a fluorine-substituted or unsubstituted C2-C20 alkenyl group, and a fluorine group, and at least one of R3 and R4 includes a fluorine atom.

3. The electrolyte according to claim 1, characterized in that The nitro organic compound includes a compound shown in Formula 3: Formula 3, Wherein, R4 to R9 are each independently any one of nitro, H, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted alkenyl, and at least one of R4 to R9 is nitro.

4. The electrolyte according to claim 2, characterized in that The fluorocarbonate compound includes one or more of methyl trifluoroethyl carbonate, ethyl trifluoroethyl carbonate, di(2-fluoroethyl) carbonate, bis(2,2,2)-trifluoroethyl carbonate, propylene trifluorocarbonate, propylene difluorocarbonate, fluoroethylene carbonate, and difluoroethylene carbonate.

5. The electrolyte according to claim 3, characterized in that The nitro organic compound includes one or more of 3-nitrophthalonitrile, 4-nitrophthalonitrile, o-nitrobenzonitrile, m-nitrobenzonitrile, p-nitrobenzonitrile, 3,5-dinitrobenzonitrile, 4-methyl-3-nitrobenzonitrile, 2-methoxy-5-nitrobenzonitrile, 4-methoxy-2-nitrobenzonitrile, 2-amino-5-nitrobenzonitrile, o-nitrophenylacetonitrile, m-nitrophenylacetonitrile, p-nitrophenylacetonitrile, and 4-nitrobenzoylacetonitrile.

6. The electrolyte according to any one of claims 1 to 5, characterized in that The volume percentage of the fluorinated carbonate compound in the total volume of the electrolyte is 1-5%; And / or, the electrolyte further comprises an electrolyte salt, and the molar percentage of the nitro organic compound in the electrolyte salt is 0.2-10%.

7. The electrolyte according to claim 6, characterized in that The electrolyte comprises a fluorine-containing lithium salt, an ether solvent and a fluorine-containing ether diluent.

8. The electrolyte according to claim 7, characterized in that The fluorine-containing lithium salt includes one or more of lithium bis(fluorosulfonyl)imide, lithium trifluoromethylsulfonyl imide, lithium bis(fluorooxalatoborate), and lithium difluorophosphate; And / or, the ether solvent includes one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and 1,3-dioxolane; And / or, the fluorine-containing ether diluent includes one or more of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 2,2,2-trifluoroethyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,3,3,3-pentafluoropropyl-2,2,2-trifluoroethyl ether, dichloromethane, dichlorobutane, and trifluoromethoxybenzene.

9. The electrolyte according to claim 8, characterized in that In the electrolyte, the molar concentration of the fluorine-containing lithium salt is 2-5 mol·L -1 ; And / or, the volume ratio of the ether solvent to the fluorinated ether diluent is 1:(1-6).

10. A battery, characterized in that: The electrolyte comprises the electrolyte according to any one of claims 1 to 9.

11. A battery pack, characterized in that: Comprising at least two batteries according to claim 10.

12. An electrical device, characterized in that: Including the battery according to claim 10 or the battery pack according to claim 11.

Images