Electrolyte and battery

Abstract

In order to solve the problems that existing batteries produce gas at high temperature and cannot be applied to special scenarios where no discharge occurs at normal temperature while discharge occurs at high temperature, an electrolyte and a battery are provided. The electrolyte comprises a lithium salt, a solvent and an additive, wherein the additive comprises vinylene carbonate, prop-1-ene-1,3-sultone and 1,3,6-hexanetricarbonitrile; based on the content of the electrolyte being 100%, the content of the additive is 0.5%-5%; the content of the vinylene carbonate is A%, the content of the prop-1-ene-1,3-sultone is B%, and the content of the 1,3,6-hexanetricarbonitrile is C%, the additive satisfying the following relational expressions: 1≤A+B≤3, 0.5≤B+C≤2, and 1.5≤(A+C) / B≤6.

Description

An electrolyte and a battery

[0001] This application claims priority to Chinese Patent Application No. 202411633560.0, filed on November 15, 2024, entitled "An Electrolyte and a Battery", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of battery technology, and more specifically to an electrolyte and a battery. Background Technology

[0003] Lithium-ion batteries are a type of rechargeable battery that primarily relies on the movement of lithium ions between the positive and negative electrodes to function. They possess advantages such as high operating voltage, high energy density, and environmental friendliness, and are widely used in consumer electronics, power batteries, and energy storage batteries. They also have broad application prospects in aerospace, defense, and other fields.

[0004] However, with the continuous advancement of technology, various mobile devices such as aircraft, ships, vehicles, and mobile communication equipment often need to operate in high-temperature environments. This necessitates a lithium-ion battery with excellent high-temperature performance, and in certain scenarios, a battery that does not discharge at room temperature but can discharge only at high temperatures. While existing battery electrolytes can accommodate both high and low temperature performance in high-voltage systems, they do not solve the problem of gas generation at high temperatures and are not suitable for certain special scenarios where the battery does not discharge at room temperature but discharges at high temperatures. Summary of the Invention

[0005] To address the problem that existing batteries produce gas at high temperatures and cannot be used in special scenarios where they do not discharge at room temperature but discharge at high temperatures, this invention provides an electrolyte and a battery.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] On one hand, the present invention provides an electrolyte comprising a lithium salt, a solvent, and an additive, wherein the additive comprises vinylene carbonate, propylene sulfonate lactone, and 1,3,6-hexanetrionitrile. Based on the electrolyte content of 100%, the content of the additive is 0.5% to 5%, the content of vinylene carbonate is A%, the content of propylene sulfonate lactone is B%, and the content of 1,3,6-hexanetrionitrile is C. The additive satisfies the following relationship:

[0008] 1≤A+B≤3, 0.5≤B+C≤2, 1.5≤(A+C) / B≤6.

[0009] Optionally, the content of vinylene carbonate is 1% to 2%, the content of propylene sulfonate lactone is 0.5% to 1%, and the content of 1,3,6-hexanetrionitrile is 0.5% to 1%.

[0010] Optionally, the additives may also include one or more of the following: vinyl sulfate, succinic anionyl, adiponitrile, 1,3-propanesulfonate lactone, methylene disulfonate, ethylene glycol bis(propionitrile) ether, fluorinated ether, 2-methylmaleic anhydride, and triallyl phosphate.

[0011] Optionally, the lithium salt content is 10% to 30%, and the solvent content is 60% to 80%.

[0012] Optionally, the lithium salt content is 15% to 20%, the solvent content is 70% to 80%, and the additive content is 1% to 3%.

[0013] Optionally, the lithium salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium methanesulfonate, lithium trifluoromethanesulfonate, lithium fluorosulfonate, lithium di(oxalate)borate, lithium di(fluorooxalate)borate, lithium di(fluoro)fluorophosphate, lithium di(fluorobis(oxalate))phosphate, lithium chloroborane, and lithium tetraphenylborate.

[0014] Optionally, the solvent includes one or more of ester solvents, ether solvents, and nitrile solvents;

[0015] The ester solvents include one or more of the following: ethylene carbonate, propylene carbonate, butyl carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene carbonate, vinylene ethylene carbonate, fluoroethylene carbonate, methyl acetate, ethyl acetate, propyl acetate, and propyl propionate.

[0016] The ether solvents include one or more of the following: 1,3-dioxolane, 1,4-dioxolane, crown ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

[0017] The nitrile solvents include one or more of acetonitrile, glutaronitrile, and malononitrile.

[0018] Optionally, the solvent is selected from fluoroethylene carbonate, propylene carbonate, and diethyl carbonate.

[0019] On the other hand, the present invention provides a battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte as described in any one of the above.

[0020] Optionally, the positive electrode sheet includes a positive electrode active material, which includes one or more of lithium cobalt oxide, lithium nickel manganese cobalt ternary materials, lithium iron phosphate, and lithium manganese oxide;

[0021] The negative electrode sheet includes a negative electrode active material, which includes one or more of graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, silicon, silicon oxide, silicon-carbon composite material, silicon alloy, metallic lithium, and lithium alloy.

[0022] In this invention, the CN- in the 1,3,6-hexanetrionitrile contained in the electrolyte can complex with high-valence metal ions, inhibiting the dissolution of metal ions under high temperature and pressure. Simultaneously, CN- also has high electronegativity, allowing it to adsorb onto the positive electrode surface, forming a CEI film to reduce the contact area between the electrolyte and the positive electrode, thus suppressing side reactions. Furthermore, CN- can capture H protons, reducing the decomposition of LiPF6 and fluoroethylene carbonate. These inhibitory effects on battery side reactions further reduce the battery's gas production. The contained vinylene carbonate forms a stable solid electrolyte interface (SEI) film on the negative electrode surface. The SEI film effectively prevents further decomposition of the electrolyte, reducing capacity loss during charge and discharge, thereby improving the battery's cycle stability and lifespan. The contained propylene sulfonate lactone forms an even more stable CEI, exhibiting higher oxidation resistance and high-temperature stability.

[0023] This application utilizes the interaction of specific amounts of vinylene carbonate, propylene sulfonate lactone, and 1,3,6-hexanetrionitrile. At room temperature, the high potential barrier of propylene sulfonate lactone (PES) leads to secondary decomposition of PES on the negative electrode surface, generating inorganic substances such as Li₂SO₃, resulting in decreased battery cycle performance. During room temperature charging, the vinylene carbonate (VC) additive undergoes a slow and persistent oxidative decomposition process, leading to gas generation and battery swelling, causing rapid capacity decay and rendering batteries using this electrolyte inoperable at room temperature. At high temperatures, the combined action of vinylene carbonate (VC), propylene sulfonate lactone (PES), and 1,3,6-hexanetrionitrile (HTCN) forms a thicker, more ordered organic / inorganic composite multilayer SEI film, exhibiting better mechanical properties and more effectively passivating the negative electrode surface, thereby suppressing continuous side reactions. At high temperatures, the PES additive can reduce the ACIR and DCIR growth rates of the battery, suppress the thermal expansion rate and cold expansion rate, and improve capacity retention and recovery rate. Meanwhile, PES has a lower LUMO orbital and a high reduction potential, making it easy to reduce and form a film on the negative electrode surface, improving the stability of the electrode-electrolyte interface, effectively improving battery performance in high-temperature environments, and also suppressing the dissolution of transition metals, further improving the temperature cycling capacity retention rate, so that batteries with the above electrolyte can work normally at high temperatures without producing gas. Detailed Implementation

[0024] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] An embodiment of the present invention provides an electrolyte comprising a lithium salt, a solvent, and an additive. The additive comprises vinylene carbonate (VC), propylene sulfonate lactone (PES), and 1,3,6-hexanetrionitrile (HTCN). Based on 100% of the electrolyte content, the content of the additive is 0.5% to 5%, the content of vinylene carbonate is A%, the content of propylene sulfonate lactone is B%, and the content of 1,3,6-hexanetrionitrile is C. The additive satisfies the following relationship:

[0026] 1≤A+B≤3, 0.5≤B+C≤2, 1.5≤(A+C) / B≤6.

[0027] In this invention, the CN- in the 1,3,6-hexanetrionitrile contained in the electrolyte can complex with high-valence metal ions, inhibiting the dissolution of metal ions under high temperature and pressure. Simultaneously, CN- also has high electronegativity, allowing it to adsorb onto the positive electrode surface, forming a CEI film to reduce the contact area between the electrolyte and the positive electrode, thus suppressing side reactions. Furthermore, CN- can capture H protons, reducing the decomposition of LiPF6 and fluoroethylene carbonate. These inhibitory effects on battery side reactions further reduce the battery's gas production. The contained vinylene carbonate forms a stable solid electrolyte interface (SEI) film on the negative electrode surface. The SEI film effectively prevents further decomposition of the electrolyte, reducing capacity loss during charge and discharge, thereby improving the battery's cycle stability and lifespan. The contained propylene sulfonate lactone forms an even more stable CEI, exhibiting higher oxidation resistance and high-temperature stability.

[0028] This application utilizes the interaction of specific amounts of vinylene carbonate, propylene sulfonate lactone, and 1,3,6-hexanetrionitrile. At room temperature, the high potential barrier of propylene sulfonate lactone (PES) leads to secondary decomposition of PES on the negative electrode surface, generating inorganic substances such as Li₂SO₃, resulting in decreased battery cycle performance. During room temperature charging, the vinylene carbonate (VC) additive undergoes a slow and persistent oxidative decomposition process, leading to gas generation and battery swelling, causing rapid capacity decay and rendering batteries using this electrolyte inoperable at room temperature. At high temperatures, the combined action of vinylene carbonate (VC), propylene sulfonate lactone (PES), and 1,3,6-hexanetrionitrile (HTCN) forms a thicker, more ordered organic / inorganic composite multilayer SEI film, exhibiting better mechanical properties and more effectively passivating the negative electrode surface, thereby suppressing continuous side reactions. At high temperatures, the PES additive can reduce the ACIR and DCIR growth rates of the battery, suppress the thermal expansion rate and cold expansion rate, and improve capacity retention and recovery rate. Meanwhile, PES has a lower LUMO orbital and a high reduction potential, making it easy to reduce and form a film on the negative electrode surface, improving the stability of the electrode-electrolyte interface, effectively improving battery performance in high-temperature environments, and also suppressing the dissolution of transition metals, further improving the temperature cycling capacity retention rate, so that batteries with the above electrolyte can work normally at high temperatures without producing gas.

[0029] Specifically, the content of the additives includes, but is not limited to, 0.5%, 0.8%, 1.0%, 1.5%, 2.0%, 2.2%, 2.5%, 3.0%, 3.2%, 3.5%, 3.8%, 4.0%, 4.2%, 4.5%, 4.8%, or 5.0%.

[0030] In some embodiments, the content of vinylene carbonate is 1% to 2%, the content of propylene sulfonate lactone is 0.5% to 1%, and the content of 1,3,6-hexanetrionitrile is 0.5% to 1%. Electrolytes meeting the above conditions can further suppress side reactions, reduce battery gas production, and improve battery cycle life.

[0031] Specifically, the content of vinylene carbonate includes, but is not limited to, 1%, 1.2%, 1.4%, 1.6%, 1.8%, or 2%. The content of propylene sulfonate lactone includes, but is not limited to, 0.5%, 0.7%, 0.9%, or 1%. The content of 1,3,6-hexanetrionitrile includes, but is not limited to, 0.5%, 0.7%, 0.9%, or 1%.

[0032] In some embodiments, the additive further includes one or more of vinyl sulfate (DTD), succinic anionyl nitrile (SN), adiponitrile (ADN), 1,3-propanesulfonate lactone (PS), methylene disulfonate (MMDS), ethylene glycol bis(propionitrile) ether (EGBE), fluorinated ether (D2), 2-methylmaleic anhydride (DMMA), and triallyl phosphate (TAP). Adding these additives can further suppress side reactions of the electrolyte during charge and discharge, reduce gas generation, improve battery expansion rate, and enhance the overcharge safety performance of the electrochemical device at high temperatures. It also provides the battery with a certain high voltage window, effectively improving the battery's storage performance under high-temperature conditions.

[0033] In some embodiments, the lithium salt content is 10% to 30%, and the solvent content is 60% to 80%. By limiting the content of lithium salt and solvent, the concentration of lithium salt can be adjusted. There is no particular limitation on the concentration of lithium salt in the electrolyte. However, when the lithium salt content is less than 10%, the number of mobile lithium ions in the electrolyte is insufficient. When the lithium salt content is more than 30%, the viscosity of the electrolyte may increase, leading to an increase in electrolyte impedance and a decrease in the lithium ion migration rate, which may result in a decrease in battery performance.

[0034] Specifically, the lithium salt content includes, but is not limited to, 10%, 13%, 16%, 18%, 20%, 25%, 27%, or 30%. The solvent content includes, but is not limited to, 60%, 64%, 66%, 68%, 70%, 71%, 72%, 73%, 74%, 75%, 77%, or 80%.

[0035] In a preferred embodiment, the lithium salt content is 15%–20%, the solvent content is 70%–80%, and the additive content is 1%–3%. An electrolyte meeting these conditions ensures the migration rate of lithium ions and further improves the electrochemical performance of the battery.

[0036] In some embodiments, the lithium salt includes at least one selected from lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium methanesulfonate, lithium trifluoromethanesulfonate, lithium fluorosulfonate, lithium dioxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium difluorobis(oxalate) phosphate, lithium chloroborane, and lithium tetraphenylborate. By selecting the above-mentioned ionizable lithium salts, the number of lithium ions that can migrate in the electrolyte is ensured.

[0037] Preferably, the lithium salt is selected from lithium hexafluorophosphate.

[0038] In some embodiments, the solvent includes one or more of ester solvents, ether solvents, and nitrile solvents;

[0039] The ester solvents include one or more of the following: ethylene carbonate (EC), propylene carbonate (PCA), butyl carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), propylene carbonate (PC), vinylene carbonate (VEC), fluoroethylene carbonate (FEC), methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), and propyl propionate (PP).

[0040] The ether solvents include one or more of the following: 1,3-dioxolane, 1,4-dioxolane, crown ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

[0041] The nitrile solvents include one or more of acetonitrile, glutaronitrile, and malononitrile.

[0042] There are no particular restrictions on the content of ester solvents, ether solvents, and nitrile solvents; they can be arbitrary within a range that does not significantly impair the performance of the lithium-ion battery of this invention. However, when using a single solvent, its lower limit relative to the total volume of the non-aqueous electrolyte is typically 3% or more, preferably 5% or more. By setting this range, a decrease in conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte can be avoided, making it easier to achieve good high-current discharge characteristics, stability relative to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery. Furthermore, the upper limit is typically 90% or less, preferably 85% or less, and more preferably 80% or less. By setting this range, the oxidation / reduction resistance of the non-aqueous electrolyte can be improved, thereby contributing to improved stability during high-temperature storage.

[0043] In a preferred embodiment, the solvent is selected from fluoroethylene carbonate, propylene carbonate, and diethyl carbonate. By using the above solvents in combination, the viscosity of the electrolyte is ensured to be within an appropriate range, thereby helping to achieve good output characteristics of the battery.

[0044] On the other hand, one embodiment of the present invention provides a battery including a positive electrode, a negative electrode, a separator, and an electrolyte as described in any one of the above.

[0045] In some embodiments, the positive electrode sheet includes a positive electrode active material, which includes one or more of lithium cobalt oxide, lithium nickel manganese cobalt ternary materials, lithium iron phosphate, and lithium manganese oxide, which helps to improve the high-temperature cycle performance of the battery.

[0046] The negative electrode sheet includes a negative electrode active material, which includes one or more of graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, silicon, silicon oxide, silicon-carbon composite material, silicon alloy, metallic lithium, and lithium alloy.

[0047] It should be noted that the materials disclosed above are merely illustrative, and any other suitable materials may be used for the positive and negative electrode active materials.

[0048] The present invention will be further illustrated by the following examples.

[0049] Example

[0050] This embodiment illustrates the electrolyte and battery disclosed in this invention, and includes the following operational steps:

[0051] Preparation of electrolyte

[0052] In an argon-filled glove box (O2 < 1 ppm, H2O < 1 ppm), the solvents FEC, PC, and DEC were mixed thoroughly by shaking and stirring in a mass ratio of 30:40:30 to obtain a mixed solvent. LiPF6 was then slowly added to the mixed solvent to obtain a mixed solution. Finally, an additive was added to the mixed solution to obtain the electrolyte.

[0053] Production of positive electrode plates:

[0054] The positive electrode material lithium cobalt oxide (NCM), conductive agent CNT, and binder PVDF are thoroughly mixed in NMP solvent at a mass ratio of 97:1.5:1.5. This slurry is then coated onto at least one side of the positive electrode current collector Al foil. After drying, rolling, die-cutting and other processes, a positive electrode sheet that meets the requirements is obtained.

[0055] Production of negative electrode plates:

[0056] The negative electrode material graphite, conductive agent SP, thickener CMC, and binder SBR are mixed in a mass ratio of 96.3:1:1.2:1.5 in an appropriate amount of deionized water solvent to obtain a uniform negative electrode slurry. This slurry is coated on at least one side of the negative electrode current collector Cu foil. After drying, rolling, die cutting and other processes, a usable negative electrode sheet is obtained.

[0057] The manufacturing process of lithium-ion batteries:

[0058] The above-mentioned positive electrode, separator, and negative electrode are stacked in sequence to obtain a bare cell. The bare cell is placed in an outer packaging bag and dried at high temperature until the water content of the electrode is less than 500 ppm. Then, the above-mentioned electrolyte is injected, and the secondary battery is prepared by vacuum sealing, settling, formation, and shaping.

[0059] Examples 1-9

[0060] The examples are used to illustrate the electrolyte and battery disclosed in this invention, including most of the operating steps in the above examples, except that the formulation in Table 1 is used.

[0061] Comparative Examples 1-7

[0062] The comparative examples are used to illustrate the electrolyte and battery disclosed in this invention, including most of the operating steps in the above embodiments, except that the formulation in Table 1 is used.

[0063] Table 1

[0064] Performance testing

[0065] I. The following performance tests were performed on the sodium-ion batteries prepared in the above embodiments and comparative examples:

[0066] High-temperature cycling test method: Charge the battery at 45℃ with a constant current and constant voltage of 1C to 4.4V, with a cutoff current of 0.05C, let it stand for 5 minutes, then discharge it at 1C to 3V, and cycle for 500 times. Record the discharge capacity C1 and the charge capacity C2 of the first cycle. Then, the initial efficiency = C2 / C1*100%; the capacity retention rate = discharge capacity of the specified number of cycles / C3*100%; the cycle life = the number of cycles when the battery capacity retention rate reaches 80%.

[0067] High-temperature storage test method: At room temperature (25℃), the battery was first charged and discharged once at 0.2C, and the discharge capacity C3 was recorded. Then, it was charged at 0.2C constant current and constant voltage to 4.4V. The battery was then placed in a constant temperature test chamber at 45℃ for 28 days and then removed. After the battery returned to room temperature, the gas production of the battery was tested using the water displacement method.

[0068] The test results are shown in Table 2.

[0069] Table 2

[0070] The results of Examples 1-9 and Comparative Examples 1-7 show that the electrolytes prepared in the examples, when used in batteries, generally exhibit better high-temperature cycling and storage performance than those in the comparative examples. This proves that the additives used in this invention can enable the battery to not work at room temperature, work normally at high temperature, and produce less gas.

[0071] The results of Examples 1 and 7 show that increasing the amount of 1,3,6-hexanetrionitrile added can significantly improve the high-temperature cycle life of the battery. This is mainly because it can form a stable CEI film on the surface of the positive electrode, prevent the effective dissolution of metal ions under high temperature and high pressure, and protect the crystal structure of the positive electrode material. It is an ideal choice for improving the high-temperature performance of the battery.

[0072] The results of Examples 5 and 6 show that when the content of vinylene carbonate additive is too high, the high-temperature cycle life will be reduced. This is because more VC will lead to an increase in the organic components of the SEI film, and the impedance will continue to increase, affecting the battery capacity.

[0073] The results of Examples 2, 3, and 4 indicate that the contents of propylene sulfonate lactone and vinylene carbonate should be kept within a certain range. At the same time, when nitrile additives form a blend system with carbonate additives, they may affect the conductivity and flame retardant properties of the electrolyte, resulting in a decrease in battery capacity and a poorer cycle life.

[0074] Example 8: The battery performance deteriorated due to excessive HTCN addition. This is mainly because the main chain structure is composed of C atoms, which greatly restricts the transport of Li+, slows down the charging and discharging speed, and reduces the actual usable capacity of the battery. At the same time, it will lead to the formation of lithium dendrites. These dendrites will pierce the separator, causing a short circuit inside the battery, thereby affecting the cycle life of the battery at high temperatures.

[0075] As shown in the test results of Example 1 and Comparative Examples 1-7, the battery will operate normally at room temperature after removing one or two of the additives. It is also important to pay attention to the ratio between the carbonate additive and the nitrile additive. Within the scope of protection of this application, the content and relationship of vinylene carbonate, propylene sulfonate lactone, and 1,3,6-hexanetrionitrile allow the additives of this invention to decompose at the positive electrode interface to form a stable CEI film, mitigating a series of adverse side reactions between the positive electrode surface and the electrolyte, thereby improving the battery cycle life. Simultaneously, the additives of this invention can also form a stable, low-resistance SEI film. Volume testing after high-temperature testing shows that gas generation is effectively suppressed, further improving the battery's high-temperature performance.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electrolyte, characterized by, The electrolyte comprises lithium salt, solvent, and additives, wherein the additives include vinylene carbonate, propylene sulfonate lactone, and 1,3,6-hexanetrionitrile. Based on the electrolyte content of 100%, the content of the additives is 0.5% to 5%, the content of vinylene carbonate is A%, the content of propylene sulfonate lactone is B, and the content of 1,3,6-hexanetrionitrile is C. The additives satisfy the following relationships: 1≤A+B≤3, 0.5≤B+C≤2, 1.5≤(A+C) / B≤6.

2. The electrolyte according to claim 1, characterized in that, The content of vinylene carbonate is 1% to 2%, the content of propylene sulfonate lactone is 0.5% to 1%, and the content of 1,3,6-hexanetrionitrile is 0.5% to 1%.

3. The electrolyte of claim 1, wherein, The additives also include one or more of the following: vinyl sulfate, succinic acid, adiponitrile, 1,3-propanesulfonate lactone, methylene disulfonate, ethylene glycol bis(propionitrile) ether, fluorinated ether, 2-methylmaleic anhydride, and triallyl phosphate.

4. The electrolyte of claim 1, wherein, The lithium salt content is 10% to 30%, and the solvent content is 60% to 80%.

5. The electrolyte according to claim 4, characterized in that, The lithium salt content is 15% to 20%, the solvent content is 70% to 80%, and the additive content is 1% to 3%.

6. The electrolyte of claim 1, wherein, The lithium salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium methanesulfonate, lithium trifluoromethanesulfonate, lithium fluorosulfonate, lithium dioxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium difluorobis(oxalate) phosphate, lithium chloroborane, and lithium tetraphenylborate.

7. The electrolyte of claim 1, wherein The solvent includes one or more of ester solvents, ether solvents, and nitrile solvents; The ester solvents include one or more of the following: ethylene carbonate, propylene carbonate, butyl carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene carbonate, vinylene ethylene carbonate, fluoroethylene carbonate, methyl acetate, ethyl acetate, propyl acetate, and propyl propionate. The ether solvents include one or more of the following: 1,3-dioxolane, 1,4-dioxolane, crown ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether. The nitrile solvents include one or more of acetonitrile, glutaronitrile, and malononitrile.

8. The electrolyte according to claim 7, characterized in that The solvent is selected from fluoroethylene carbonate, propylene carbonate and diethyl carbonate.

9. A battery, characterized by It includes a positive electrode, a negative electrode, a separator, and the electrolyte as described in any one of claims 1-8.

10. The battery of claim 9, wherein, The positive electrode sheet includes a positive electrode active material, which includes one or more of lithium cobalt oxide, lithium nickel manganese cobalt ternary materials, lithium iron phosphate, and lithium manganese oxide. The negative electrode sheet includes a negative electrode active material, which includes one or more of graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, silicon, silicon oxide, silicon-carbon composite material, silicon alloy, metallic lithium, and lithium alloy.

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