A non-aqueous electrolyte and battery

Abstract

To overcome the problems of uneven surface thickness, poor high-temperature stability, low ionic conductivity, and high impedance in existing SEI films in batteries, this invention provides a non-aqueous electrolyte, comprising a solvent, an electrolyte salt, and a compound shown in structural formula 1. This invention also discloses a battery comprising the above-mentioned non-aqueous electrolyte. The non-aqueous electrolyte provided by this invention exhibits high stability and durability, while effectively improving the stability of the SEI film.

Description

Technical Field

[0001] This invention belongs to the field of secondary battery technology, specifically relating to a non-aqueous electrolyte and battery. Background Technology

[0002] In various energy storage devices, such as lithium-ion batteries, where metals or metal-ion complexes serve as negative and positive electrode materials, various additives play a crucial role in enhancing their performance. Among these, film-forming additives are particularly important. For example, in lithium-ion batteries, film-forming additives preferentially undergo redox reactions before the electrolyte, forming a solid electrolyte film near the electrodes. This film is called the SEI film at the negative electrode and the CEI film at the positive electrode. It can mitigate the reaction between the electrolyte and electrode materials, regulate lithium-ion permeability, and reduce electronic conductivity, thereby improving the battery's high and low temperature performance and cycle life. However, the SEI films formed by additives currently have drawbacks such as uneven film thickness, poor high-temperature stability, low lithium-ion conductivity, and high impedance, all of which negatively impact battery life and high-rate discharge. Summary of the Invention

[0003] To address the problems of uneven surface thickness, poor high-temperature stability, low ionic conductivity, and high impedance in existing SEI films in batteries, this invention provides a non-aqueous electrolyte and battery.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] On one hand, the present invention provides a non-aqueous electrolyte comprising a solvent, an electrolyte salt, and a compound represented by structural formula 1:

[0006]

[0007] Where z is selected from 0 or 1; m and c are each independently selected from any natural number from 1 to 3; p is selected from any natural number from 0 to 3;

[0008] When z = 0, n = 1; when z = 1, n = 0 or 1.

[0009] E1 and E2 are each independently selected from five-membered ring cyclic carbonate groups and their derivatives, five-membered ring cyclic sulfite groups and their derivatives, five-membered ring cyclic sulfate groups and their derivatives, five-membered ring cyclic sulfonate groups and their derivatives, or five-membered ring sulfite groups and their derivatives. E1 and E2 may be the same or different.

[0010] A is selected from halogens, lithium, sodium, C1-C4 halogenated hydrocarbon groups, cyclic carbonate groups and their derivatives, cyclic sulfite groups and their derivatives, cyclic sulfate groups and their derivatives, cyclic sulfonate groups and their derivatives, or cyclic sulfinate groups and their derivatives.

[0011] Optionally, E1 and E2 may be independently selected from the following groups:

[0012]

[0013] Optionally, when z = 0, A is selected from cyclic carbonate groups and their derivatives, cyclic sulfite groups and their derivatives, cyclic sulfate groups and their derivatives, cyclic sulfonate groups and their derivatives, or cyclic sulfite groups and their derivatives.

[0014] When z = 1, A is selected from halogens, lithium, sodium, C1-C4 halogenated hydrocarbon groups, cyclic carbonate groups and their derivatives, cyclic sulfite groups and their derivatives, cyclic sulfate groups and their derivatives, cyclic sulfonate groups and their derivatives, or cyclic sulfinate groups and their derivatives.

[0015] Optional, m and c are the same, and E1 and E2 are the same.

[0016] Optionally, m, c, and p are the same, and E1 and E2 are the same.

[0017] Optionally, A is selected from the group shown in structural formula 2 or structural formula 3:

[0018]

[0019] Where a and b are natural numbers and a+b=1 or 2; d=1 or 2, when d=2, Y is a sulfur atom; when d=1, Y is a sulfur atom or a carbon atom;

[0020]

[0021] Where i and k are natural numbers and i+k = 1, 2 or 3, j = 1 or 2.

[0022] Optionally, the compound represented by structural formula 1 is selected from one or more of the following compounds:

[0023]

[0024]

[0025] Optionally, based on the total mass of the non-aqueous electrolyte as 100%, the amount of the compound represented by structural formula 1 added is 0.05-10%.

[0026] Optionally, the electrolyte salt is selected from LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, Li2B 10 Cl 10 At least one of the following: lithium salts of lower aliphatic carboxylic acids.

[0027] Optionally, the non-aqueous electrolyte further includes auxiliary additives, which include at least one of cyclic sulfate compounds, sulfonyl lactone compounds, cyclic carbonate compounds, unsaturated phosphate compounds, and nitrile compounds.

[0028] Preferably, the cyclic sulfate compound is selected from at least one of vinyl sulfate, propylene sulfate, or methyl vinyl sulfate;

[0029] The sulfonyl lactone compound is selected from at least one of 1,3-propanesulfonyl lactone, 1,4-butanesulfonyl lactone, or 1,3-propenesulfonyl lactone.

[0030] The cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate, or the compound shown in structural formula 4.

[0031]

[0032] In structural formula 4, R 21 R 22 R 23 R 24 R 25 R 26 Each is independently selected from one of the following: hydrogen atom, halogen atom, or C1-C5 group;

[0033] The unsaturated phosphate compound is selected from at least one of the compounds shown in structural formula 5:

[0034]

[0035] In structural formula 5, R 31 R 32 R 32 Each independent group is selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halohydrocarbon groups, and -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 R 32 R 33At least one of them is an unsaturated hydrocarbon group;

[0036] The nitrile compounds include one or more of the following: succinic acid, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrionitrile, adiponitrile, heptacyanide, octadionitrile, nonadionitrile, and sebaconitol.

[0037] On the other hand, the present invention provides a battery including a positive electrode, a negative electrode, and a non-aqueous electrolyte as described above.

[0038] According to the non-aqueous electrolyte provided by this invention, the inventors, through research and speculation, believe that by using the compound shown in structural formula 1 as a film-forming additive, which has a phosphate ester as the central group and is externally connected to at least two five-membered ring structures, it provides the possibility of generating at least two or more lithium salts in the same molecule, depending on different requirements. When the group is not removed, its five-membered ring structure can open to form lithium salts (such as lithium sulfate, lithium sulfite, lithium carbonate, etc.), or two or more five-membered ring structures can participate in the reaction to generate an SEI film with a cross-linked structure, enhancing film stability and improving battery life and cycle performance. If one or two groups on the compound shown in structural formula 1 are removed, lithium phosphate containing organic segments can be formed in the SEI film and doped with other types of inorganic lithium salts. At the same time, the compound shown in structural formula 1 is a phosphate ester, phosphite, or phosphonate compound formed with a phosphorus atom as the central atom. In this type of compound, the probability of the groups directly bonded to phosphorus leaving stepwise is much higher than the probability of simultaneous departure, and the leaving ability becomes relatively difficult as the number of substituents decreases. This increases the probability of forming SEI films with cross-linked organic-inorganic salt structures and their duration, thereby improving the stability and durability of the SEI interface and optimizing its high-temperature and cycling performance. This type of structure can reduce the probability of a single film-forming additive forming a large-area crystal structure, forming small grains that interact with organic matter, resulting in high flexibility and increased lithium-ion activity on the crystal surface. This improves the lithium conductivity of the SEI film while enhancing its structural strength, ultimately achieving comprehensive advantages such as improved battery discharge efficiency, room temperature performance, and high and low temperature cycling performance. Detailed Implementation

[0039] 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.

[0040] One embodiment of the present invention provides a non-aqueous electrolyte, comprising a solvent, an electrolyte salt, and a compound shown in structural formula 1:

[0041]

[0042] Where z is selected from 0 or 1; m and c are each independently selected from any natural number from 1 to 3; p is selected from any natural number from 0 to 3;

[0043] When z = 0, n = 1; when z = 1, n = 0 or 1.

[0044] E1 and E2 are each independently selected from five-membered ring carbonate groups and their derivatives, five-membered ring sulfite groups and their derivatives, five-membered ring sulfate groups and their derivatives, five-membered ring sulfonate groups and their derivatives, or five-membered ring sulfite groups and their derivatives. E1 and E2 may be the same or different.

[0045] A is selected from halogens, lithium, sodium, C1-C4 halogenated hydrocarbon groups, cyclic carbonate groups and their derivatives, cyclic sulfite groups and their derivatives, cyclic sulfate groups and their derivatives, cyclic sulfonate groups and their derivatives, or sulfinate groups and their derivatives.

[0046] According to the non-aqueous electrolyte provided by this invention, the inventors, through research and speculation, believe that by using the compound shown in structural formula 1 as a film-forming additive, which has a phosphate ester as the central group and is externally connected to at least two five-membered ring structures, it provides the possibility of generating at least two or more lithium salts in the same molecule, depending on different requirements. When the group is not removed, its five-membered ring structure can open to form lithium salts (such as lithium sulfate, lithium sulfite, lithium carbonate, etc.), or two or more five-membered ring structures can participate in the reaction to generate an SEI film with a cross-linked structure, enhancing film stability and improving battery life and cycle performance. If one or two groups on the compound shown in structural formula 1 are removed, lithium phosphate containing organic segments can be formed in the SEI film and doped with other types of inorganic lithium salts. At the same time, the compound shown in structural formula 1 is a phosphate ester, phosphite, or phosphonate compound formed with a phosphorus atom as the central atom. In this type of compound, the probability of the groups directly bonded to phosphorus leaving stepwise is much higher than the probability of simultaneous departure, and the leaving ability becomes relatively difficult as the number of substituents decreases. This increases the probability of forming SEI films with cross-linked organic-inorganic salt structures and their duration, thereby improving the stability and durability of the SEI interface and optimizing its high-temperature and cycling performance. This type of structure can reduce the probability of a single film-forming additive forming a large-area crystal structure, forming small grains that interact with organic matter, resulting in high flexibility and increased lithium-ion activity on the crystal surface. This improves the lithium conductivity of the SEI film while enhancing its structural strength, ultimately achieving comprehensive advantages such as improved battery discharge efficiency, room temperature performance, and high and low temperature cycling performance.

[0047] In the description of this invention, "cyclic carbonate groups and their derivatives" refers to groups containing one or more carbon atoms in a cyclic carbon chain that are substituted by carbonate groups, and groups containing one or more hydrogen atoms in a cyclic carbon chain that are substituted. The substituted groups can be hydrocarbon groups, halogens, halocarbon groups, etc. "Cyclic sulfite groups and their derivatives," "cyclic sulfate groups and their derivatives," "cyclic sulfonate groups and their derivatives," and "cyclic sulfinate groups and their derivatives" can be understood using this definition.

[0048] The halogens mentioned above include F, Cl, Br, and I.

[0049] As described above, a halogenated hydrocarbon group is one in which at least one hydrogen atom is replaced by a halogen.

[0050] In a preferred embodiment, E1 and E2 are each independently selected from the following groups:

[0051]

[0052] In some embodiments, when z = 0, A is selected from cyclic carbonate groups and their derivatives, cyclic sulfite groups and their derivatives, cyclic sulfate groups and their derivatives, cyclic sulfonate groups and their derivatives, or cyclic sulfite groups and their derivatives.

[0053] When z = 1, A is selected from halogens, lithium, sodium, C1-C4 halogenated hydrocarbon groups, cyclic carbonate groups and their derivatives, cyclic sulfite groups and their derivatives, cyclic sulfate groups and their derivatives, cyclic sulfonate groups and their derivatives, or cyclic sulfinate groups and their derivatives. When substituted, the halogenated hydrocarbon group is preferably a fluorocarbon group.

[0054] In a preferred embodiment, m and c are the same, and E1 and E2 are the same.

[0055] In a preferred embodiment, m, c, and p are all the same, and E1 and E2 are the same.

[0056] In a preferred embodiment, A is selected from the group shown in structural formula 2 or structural formula 3:

[0057]

[0058] Where a and b are natural numbers and a+b=1 or 2; d=1 or 2, when d=2, Y is a sulfur atom; when d=1, Y is a sulfur atom or a carbon atom;

[0059]

[0060] Where i and k are natural numbers and i+k = 1, 2 or 3, j = 1 or 2.

[0061] In a preferred embodiment, when z = 0, A is selected from the group shown in structural formula 2 or the group shown in structural formula 3;

[0062] When z = 1, A is selected from halogens, lithium, sodium, C1-C4 halogenated hydrocarbon groups, the group shown in structural formula 2, or the group shown in structural formula 3.

[0063] The present invention will be described below using specific compounds:

[0064] (1) When z = 0, n = 1, m = c = 1, and A is selected from the group shown in structural formula 2 or the group shown in structural formula 3, as an example, the compound shown in structural formula 1 can be selected from:

[0065]

[0066] (2) When z = 1, n = 1, m = c = 1, p = 1, and A is selected from the group shown in structural formula 2 or the group shown in structural formula 3, as an example, the compound shown in structural formula 1 can be selected from:

[0067]

[0068] (3) When z = 1, n = 0, m = c = 1, p = 1, and A is selected from the group shown in structural formula 2 or the group shown in structural formula 3, as an example, the compound shown in structural formula 1 can be selected from:

[0069]

[0070] (4) When z = 0, n = 1, m = c = 1, p = 0 or 1, and A is selected from lithium or fluorinated hydrocarbon groups, as an example, the compound shown in structural formula 1 can be selected from:

[0071]

[0072] (5) When z = 1, n = 1, m = c = 1, p = 0 or 1, and A is selected from fluorine, lithium, or fluorinated hydrocarbon groups, as an example, the compound shown in structural formula 1 can be selected from:

[0073]

[0074] The above compounds can be used alone or in combination of two or more.

[0075] Those skilled in the art, knowing the structural formula of the compound of structural formula 1, can understand the preparation method of the above-mentioned compound based on common knowledge in the field of chemical synthesis. As an example of the present invention:

[0076] (1) When z = 0 or 1, n = 1, m = c = 1, and A is selected from the group shown in structural formula 2 or structural formula 3, the compound shown in structural formula 1 can be prepared by the following method:

[0077] Phosphorus oxychloride or phosphorus trichloride is first reacted with two equivalents of compound 21, compound 22, compound 23, compound 24 or compound 25 in the presence of an acid-binding agent to undergo a metathesis reaction, and then reacted with an excess of the compound shown in structural formula 6 or the compound shown in structural formula 7 in the presence of an acid-binding agent to generate the compound shown in structural formula 1.

[0078]

[0079]

[0080] Where a and b are natural numbers and a+b=1 or 2; p is selected from any natural number from 0 to 3; d=1 or 2, when d=2, Y is a sulfur atom; when d=1, Y is a sulfur atom or a carbon atom.

[0081]

[0082] Where i and k are natural numbers and i+k = 1, 2 or 3; j = 1 or 2, and p is selected from any natural number from 0 to 3.

[0083] (2) When z = 0, n = 1, m = c = 1, and A is selected from the group shown in structural formula 2 or structural formula 3, the compound shown in structural formula 1 can be prepared by the following method:

[0084] Phosphorus trichloride is first reacted with three equivalents of compounds 21, 22, 23, 24, or 25 in the presence of an acid-binding agent to generate an intermediate, which is then rearranged with the compound shown in structural formula 8 or 9 to generate the compound shown in structural formula 1.

[0085]

[0086] Where a and b are natural numbers and a+b=1 or 2; p is selected from any natural number from 0 to 3; d=1 or 2, when d=2, Y is a sulfur atom; when d=1, Y is a sulfur atom or a carbon atom.

[0087]

[0088] Where i and k are natural numbers and i+k = 1, 2 or 3; j = 1 or 2, and p is selected from any natural number from 0 to 3.

[0089] (3) When z = 0 or 1, m = c = 1, p = 0, and A is selected from lithium or sodium, the compound shown in structural formula 1 can be prepared by the following method:

[0090] Phosphorus oxychloride or phosphorus trichloride is first reacted with three equivalents of compound 21, compound 22, compound 23, compound 24 or compound 25 in the presence of an acid-binding agent to undergo a metathesis reaction, and then reacted with lithium hydroxide or sodium hydroxide in an organic solvent to generate the compound shown in structural formula 1.

[0091] (4) When z = 0 or 1, m = c = 1, and A is selected from a haloalkyl group, the compound shown in structural formula 1 can be prepared by the following method:

[0092] Phosphorus oxychloride or phosphorus trichloride is first reacted with two equivalents of compound 21, compound 22, compound 23, compound 24 or compound 25 in the presence of an acid-binding agent to undergo a metathesis reaction, and then reacted with an excess of the compound shown in structural formula 10 in the presence of an acid-binding agent to generate the compound shown in structural formula 1.

[0093]

[0094] Where M is a C1 to C4 haloalkyl group.

[0095] (5) When z = 0 or 1, n = 0, m = c = 1, p = 0, and A is selected from fluorine atoms, the compound shown in structural formula 1 can be prepared by the following method:

[0096] Phosphorus oxychloride or phosphorus trichloride is first reacted with two equivalents of compound 21, compound 22, compound 23, compound 24 or compound 25 in the presence of an acid-binding agent to undergo a metathesis reaction, and then reacted with equivalents of fluoride salts, such as potassium fluoride, cobalt fluoride, cesium fluoride, etc., to directly fluorinate and generate the compound shown in structural formula 1.

[0097] In some embodiments, the amount of compound represented by structural formula 1 added is 0.05 to 10% based on the total mass of the non-aqueous electrolyte as 100%.

[0098] In a preferred embodiment, the amount of the compound represented by structural formula 1 added is 0.1-5% based on the total mass of the non-aqueous electrolyte being 100%.

[0099] Specifically, the amount of the compound represented by structural formula 1 added can be 0.05%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.4%, 1.9%, 2.1%, 2.3%, 2.8%, 3.2%, 3.7%, 4.0%, 4.5%, 5%, 5.5%, 6.2%, 6.8%, 7.7%, 8.8%, 9.3%, or 10%.

[0100] When the amount of compound shown in structural formula 1 is within the above range, it can effectively improve the high-temperature storage performance of the battery. If the amount of compound shown in structural formula 1 is too small, it will be difficult to significantly improve the performance of the battery. If the amount of compound shown in structural formula 1 is too large, it may affect the function of other substances in the electrolyte due to the excessive decomposition products.

[0101] In some embodiments, the electrolyte salt includes one or more of lithium, sodium, potassium, magnesium, zinc, and aluminum salts. In a preferred embodiment, the electrolyte salt is selected from lithium or sodium salts.

[0102] In a preferred embodiment, the lithium salt is selected from LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, and Li2B. 10 Cl 10 At least one of the following: lower aliphatic carboxylic acid lithium salts. If the electrolyte salt is selected from other salts such as sodium salts, potassium salts, magnesium salts, zinc salts, or aluminum salts, the lithium in the lithium salt can be replaced with sodium, potassium, magnesium, zinc, or aluminum.

[0103] In a preferred embodiment, the sodium salt is selected from at least one of sodium perchlorate (NaClO4), sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium trifluoromethanesulfonate (NaFSI), and sodium bis(trifluoromethanesulfonate) (NaTFSI).

[0104] In some embodiments, the concentration of the electrolyte salt in the non-aqueous electrolyte is 0.1 mol / L to 8 mol / L. In a preferred embodiment, the concentration of the electrolyte salt in the non-aqueous electrolyte is 0.5 mol / L to 2.5 mol / L. Specifically, the concentration of the electrolyte salt can be 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, or 2.5 mol / L.

[0105] In some embodiments, the non-aqueous electrolyte further includes auxiliary additives, which include at least one of cyclic sulfate compounds, sulfonyl lactone compounds, cyclic carbonate compounds, unsaturated phosphate compounds, and nitrile compounds.

[0106] Preferably, the cyclic sulfate compound is selected from at least one of vinyl sulfate, propylene sulfate, or methyl vinyl sulfate;

[0107] The sulfonyl lactone compound is selected from at least one of 1,3-propanesulfonyl lactone, 1,4-butanesulfonyl lactone, or 1,3-propenesulfonyl lactone.

[0108] The cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate, or the compound shown in structural formula 4.

[0109]

[0110] In structural formula 4, R 21 R 22 R 23 R 24 R 25 R 26 Each is independently selected from one of the following: hydrogen atom, halogen atom, or C1-C5 group;

[0111] The unsaturated phosphate compound is selected from at least one of the compounds shown in structural formula 5:

[0112]

[0113] In structural formula 5, R 31 R 32 R 32 Each independent group is selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halohydrocarbon groups, and -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 R 32 R 33 At least one of them is an unsaturated hydrocarbon group. Specifically, the unsaturated phosphate ester compound may be at least one of the following: triargyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl trifluoromethyl phosphate, diallyl-2,2,2-trifluoroethyl phosphate, diallyl-3,3,3-trifluoropropyl phosphate, diallyl hexafluoroisopropyl phosphate, triallyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl trifluoromethyl phosphate, diallyl-2,2,2-trifluoroethyl phosphate, diallyl-3,3,3-trifluoropropyl phosphate, and diallyl hexafluoroisopropyl phosphate.

[0114] The nitrile compounds include one or more of the following: succinic acid, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrionitrile, adiponitrile, heptacyanide, octadionitrile, nonadionitrile, and sebaconitol.

[0115] It should be noted that, unless otherwise specified, the amount of any one of the optional substances in the auxiliary additives added to the non-aqueous electrolyte is generally 0.05% to 10%, preferably 0.1% to 5%, and more preferably 0.1% to 3%. Specifically, the amount of any one of the optional substances in the auxiliary additives can be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8%, 8.5%, 9%, 9.5%, or 10%.

[0116] In some embodiments, when the auxiliary additive is selected from fluoroethylene carbonate, the amount of fluoroethylene carbonate added is 0.05% to 30% based on 100% of the total mass of the non-aqueous electrolyte.

[0117] In the non-aqueous electrolyte, compared with single addition or combination of other existing additives, the compound shown in structural formula 1, when added together with the auxiliary additive, exhibits a significant synergistic effect in improving the high-temperature storage performance of the battery. This indicates that the compound shown in structural formula 1 and the auxiliary additive, when forming a film together on the electrode surface, can compensate for the film-forming defects of single addition, resulting in a more stable passivation film under high-temperature conditions.

[0118] In a preferred embodiment, the auxiliary additive is selected from vinyl sulfate.

[0119] In some embodiments, the solvent includes one or more of ether solvents, nitrile solvents, carbonate solvents, carboxylic acid ester solvents, and sulfone solvents.

[0120] In some embodiments, the ether solvent includes cyclic ethers or chain ethers, preferably chain ethers with 3 to 10 carbon atoms and cyclic ethers with 3 to 6 carbon atoms. The cyclic ethers may be, but are not limited to, one or more of 1,3-dioxolane (DOL), 1,4-dioxane (DX), crown ethers, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH3-THF), and 2-trifluoromethyltetrahydrofuran (2-CF3-THF). The chain ethers may be, but are not limited to, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether. Because chain ethers have high solvation ability with lithium ions and can improve ion dissociation, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane, which have low viscosity and can impart high ionic conductivity, are particularly preferred. Ether compounds can be used alone or in any combination and ratio of two or more. There are no particular restrictions on the amount of ether compounds added; it is arbitrary as long as it does not significantly impair the performance of the high-pressure lithium-ion battery of this invention. Typically, the volume ratio is 1% or more, preferably 2% or more, and more preferably 3% or more when the non-aqueous solvent volume ratio is 100%. Furthermore, the volume ratio is typically 30% or less, preferably 25% or less, and more preferably 20% or less. When using two or more ether compounds in combination, the total amount of ether compounds should meet the above-mentioned range. When the amount of ether compounds added is within the above-mentioned preferred range, it is easy to ensure the improved ionic conductivity resulting from the increased lithium-ion dissociation degree and reduced viscosity of the chain ethers. Additionally, when the negative electrode active material is a carbon material, the phenomenon of co-intercalation between the chain ethers and lithium ions can be suppressed, thus enabling the input / output characteristics and charge / discharge rate characteristics to reach an appropriate range.

[0121] In some embodiments, the nitrile solvent may be, but is not limited to, one or more of acetonitrile, glutaronitrile, and malononitrile.

[0122] In some embodiments, the carbonate solvent includes cyclic carbonates or chain carbonates. Cyclic carbonates may specifically be, but are not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), and butylene carbonate (BC); chain carbonates may specifically be, but are not limited to, one or more of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and dipropyl carbonate (DPC). The content of cyclic carbonates is not particularly limited and is arbitrary within a range that does not significantly impair the performance of the high-pressure lithium-ion battery of this invention. However, when using a single type, its lower limit relative to the total volume of the non-aqueous electrolyte solvent 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 enhanced stability during high-temperature storage. The content of the chain carbonate is not particularly limited, but relative to the total amount of solvent in the non-aqueous electrolyte, it is typically 15% or more by volume, preferably 20% or more, and more preferably 25% or more. Furthermore, it is typically 90% or less by volume, preferably 85% or less, and more preferably 80% or less. By keeping the chain carbonate content within the above range, it is easier to achieve an appropriate viscosity for the non-aqueous electrolyte, suppressing the decrease in ionic conductivity, and thus contributing to achieving a favorable range of output characteristics for the non-aqueous electrolyte battery. When using two or more chain carbonates in combination, it is sufficient to ensure that the total amount of chain carbonate meets the above range.

[0123] In some embodiments, fluorine-containing chain carbonates (hereinafter referred to as "fluorinated chain carbonates") are also preferably used. There is no particular limitation on the number of fluorine atoms in a fluorinated chain carbonate as long as it is 1 or more, but it is generally 6 or less, preferably 4 or less. When a fluorinated chain carbonate has multiple fluorine atoms, these fluorine atoms can be bonded to the same carbon atom or to different carbon atoms. Examples of fluorinated chain carbonates include dimethyl fluorinated carbonate derivatives, methyl ethyl fluorinated carbonate derivatives, and diethyl fluorinated carbonate derivatives.

[0124] In some embodiments, the carboxylic acid ester solvent may be, but is not limited to, one or more of methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate.

[0125] In some embodiments, the sulfone solvent includes cyclic sulfones and chain sulfones, but preferably, in the case of cyclic sulfones, it is typically a compound with 3 to 6 carbon atoms, more preferably 3 to 5 carbon atoms, and in the case of chain sulfones, it is typically a compound with 2 to 6 carbon atoms, more preferably 2 to 5 carbon atoms. There are no particular limitations on the amount of sulfone solvent added, and it is arbitrary within a range that does not significantly impair the performance of the high-pressure lithium-ion battery of the present invention. Relative to the total amount of solvent in the non-aqueous electrolyte, it is typically 0.3% or more by volume, preferably 0.5% or more by volume, more preferably 1% or more by volume, and typically 40% or less by volume, preferably 35% or less by volume, more preferably 30% or less by volume. When using two or more sulfone solvents in combination, the total amount of sulfone solvent should satisfy the above range. When the amount of sulfone solvent added is within the above range, an electrolyte with excellent high-temperature storage stability is tended to be obtained.

[0126] Another embodiment of the present invention provides a battery including a positive electrode, a negative electrode, and a non-aqueous electrolyte as described above.

[0127] Because the battery uses the non-aqueous electrolyte described above, it can form a high-performance passivation film on the positive and negative electrodes, thereby effectively improving the battery's high-temperature storage performance and high-temperature cycle performance, and enhancing the battery's power characteristics.

[0128] In some embodiments, the battery is a secondary battery, which may be a lithium secondary battery, potassium secondary battery, sodium secondary battery, magnesium secondary battery, zinc secondary battery, aluminum secondary battery, etc.

[0129] In a preferred embodiment, the battery is a lithium metal battery, a lithium-ion battery, a lithium-sulfur battery, or a sodium-ion battery.

[0130] In some embodiments, the positive electrode includes a positive electrode active material layer, which includes a positive electrode active material. The type and content of the positive electrode active material are not particularly limited and can be selected according to actual needs. It can be any positive electrode active material or conversion type positive electrode material that can reversibly insert / deintercalate metal ions (lithium ions, sodium ions, potassium ions, magnesium ions, zinc ions, aluminum ions, etc.).

[0131] In a preferred embodiment, the battery is a lithium-ion battery, and its positive electrode active material can be selected from LiFe. 1-x’ M' x’ PO4, LiMn 2-y’ M y’ O4 and LiNi x Co y Mn z M 1-x-y-zOne or more of O2, wherein M' is selected from one or more of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, and M is selected from one or more of Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, and 0≤x'<1, 0≤y'≤1, 0≤y≤1, 0≤x≤1, 0≤z≤1, x+y+z≤1. The positive electrode active material may also be selected from one or more of sulfides, selenides, and halides. More preferably, the positive electrode active material may be selected from LiCoO2, LiFePO4, LiFe 0.8 Mn 0.2 PO4, LiMn2O4, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.5 Co 0.2 Mn 0.2 Al 0.1 O2, LiNi 0.5 Co 0.2 Al 0.3 One or more of O2.

[0132] In a preferred embodiment, the battery is a sodium-ion battery, and its positive electrode active material is selected from one or more of metallic sodium, carbon materials, alloy materials, over-plated metal oxides, over-plated metal sulfides, phosphorus-based materials, titanate materials, and Prussian blue-based materials. The carbon material is selected from one or more of graphite, soft carbon, and hard carbon. The alloy material is selected from an alloy composed of at least two of Si, Ge, Sn, Pb, and Sb. The alloy material can also be selected from an alloy composed of at least one of Si, Ge, Sn, Pb, and Sb with C. The chemical formula of the over-plated metal oxide and the over-plated metal sulfide is M1. x N y M1 can be selected from one or more of Fe, Co, Ni, Cu, Mn, Sn, Mo, Sb, and V; N is selected from O or S; the phosphorus-based material can be selected from one or more of red phosphorus, white phosphorus, and black phosphorus; and the titanate material can be selected from Na2Ti3O7 and Na2Ti6O7. 13 Na4Ti5O 12 Li4Ti5O 12 One or more of NaTi2(PO4)3, wherein the molecular formula of the Prussian blue material is Nax M[M′(CN)6] y ·zH₂O, where M is a transition metal, M′ is a transition metal, and 0 <x≤2,0.8≤y<1,0<z≤20。

[0133] In some embodiments, the positive electrode further includes a positive electrode current collector, and the positive electrode material layer covers the surface of the positive electrode current collector.

[0134] The positive electrode current collector is selected from a metallic material that can conduct electrons. Preferably, the positive electrode current collector includes one or more of Al, Ni, tin, copper, and stainless steel. In a more preferred embodiment, the positive electrode current collector is selected from aluminum foil.

[0135] In some embodiments, the positive electrode active material layer further includes a positive electrode binder and a positive electrode conductive agent, and the positive electrode active material, the positive electrode binder and the positive electrode conductive agent are blended to obtain the positive electrode active material layer.

[0136] The positive electrode binder includes one or more of the following: polyvinylidene fluoride (PVDF), copolymers of PVDF, polytetrafluoroethylene (PTFE), copolymers of PVDF-hexafluoropropylene, copolymers of tetrafluoroethylene-hexafluoropropylene, copolymers of tetrafluoroethylene-perfluoroalkyl vinyl ethers, copolymers of ethylene-tetrafluoroethylene, copolymers of PVDF-tetrafluoroethylene, copolymers of PVDF-trifluoroethylene, copolymers of PVDF-trichloroethylene, copolymers of PVDF-fluorinated vinylidene, copolymers of PVDF-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, polyethylene, and polypropylene; acrylic resins; and styrene-butadiene rubber.

[0137] The positive electrode conductive agent includes one or more of conductive carbon black, conductive carbon spheres, conductive graphite, conductive carbon fiber, carbon nanotubes, graphene, or reduced graphene oxide.

[0138] In some embodiments, the negative electrode includes a negative electrode material layer, the negative electrode material layer includes a negative electrode active material, and the negative electrode active material includes one or more of carbon-based negative electrodes, tin-based negative electrodes, silicon-based negative electrodes, lithium negative electrodes, sodium negative electrodes, potassium negative electrodes, magnesium negative electrodes, zinc negative electrodes, and aluminum negative electrodes. The carbon-based negative electrode may include graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, etc.; the silicon-based negative electrode may include one or more of silicon materials, silicon oxides, silicon-carbon composite materials, and silicon alloy materials; the tin-based negative electrode may include tin, tin-carbon, tin oxide, and tin metal compounds; the lithium negative electrode may include metallic lithium or lithium alloys. Specifically, the lithium alloy may be at least one of lithium-silicon alloys, lithium-sodium alloys, lithium-potassium alloys, lithium-aluminum alloys, lithium-tin alloys, and lithium-indium alloys.

[0139] In some embodiments, the negative electrode further includes a negative electrode current collector, and the negative electrode material layer covers the surface of the negative electrode current collector. The material of the negative electrode current collector may be the same as that of the positive electrode current collector, and will not be described in detail here.

[0140] In some embodiments, the negative electrode material layer further includes a negative electrode binder and a negative electrode conductive agent, and the negative electrode active material, the negative electrode binder, and the negative electrode conductive agent are blended to obtain the negative electrode material layer. The negative electrode binder and the negative electrode conductive agent can be the same as the positive electrode binder and the positive electrode conductive agent, respectively, and will not be described in detail here.

[0141] In some embodiments, the battery further includes a separator located between the positive electrode and the negative electrode.

[0142] The diaphragm can be a conventional diaphragm, such as a ceramic diaphragm, a polymer diaphragm, a non-woven fabric, or an inorganic-organic composite diaphragm, including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), double-layer PP / PE, double-layer PP / PP, and triple-layer PP / PE / PP diaphragms.

[0143] The present invention will be further illustrated by the following examples.

[0144] The compounds represented by structural formula 1 used in the following examples are shown in the table below:

[0145]

[0146]

[0147] Examples 1-14

[0148] This embodiment illustrates the preparation method of the non-aqueous electrolyte and battery disclosed in this invention, including the following steps:

[0149] 1) Preparation of non-aqueous electrolyte:

[0150] Ethylene carbonate (EC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC) were mixed in a mass ratio of EC:DEC:EMC = 1:1:1. Then, lithium hexafluorophosphate (LiPF6) was added to a molar concentration of 1 mol / L. Based on the total weight of the non-aqueous electrolyte as 100%, additives were added in the mass percentages shown in Examples 1 to 14 of Tables 1 to 4.

[0151] 2) Preparation of the positive electrode plate:

[0152] The positive electrode active material, lithium nickel cobalt manganese oxide (LiNiO), was mixed in a mass ratio of 93:4:3. 0.5 Co 0.2 Mn 0.3O2, conductive carbon black Super-P, and binder polyvinylidene fluoride (PVDF) are dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a positive electrode slurry. The slurry is uniformly coated on both sides of an aluminum foil, dried, calendered, and vacuum dried, and then aluminum leads are welded on using an ultrasonic welder to obtain a positive electrode plate with a thickness between 120-150 μm.

[0153] 3) Preparation of the negative electrode plate:

[0154] Artificial graphite, conductive carbon black Super-P, styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) were mixed in a mass ratio of 94:1:2.5:2.5, and then dispersed in deionized water to obtain a negative electrode slurry. The slurry was coated on both sides of a copper foil, dried, calendered, and vacuum dried, and then nickel leads were welded on using an ultrasonic welder to obtain a negative electrode plate with a thickness between 120-150 μm.

[0155] 4) Cell fabrication:

[0156] A three-layer separator with a thickness of 20 μm is placed between the positive and negative plates. Then, the sandwich structure composed of the positive plate, negative plate and separator is wound up, and the wound body is flattened and placed in an aluminum foil packaging bag. It is then vacuum baked at 75°C for 48 hours to obtain the cell to be injected with electrolyte.

[0157] 5) Electrolyte injection and formation of the battery cell:

[0158] In a glove box where the dew point is controlled below -40°C, the electrolyte prepared above is injected into the battery cell, vacuum sealed, and left to stand for 24 hours.

[0159] The initial formation was then performed as follows: constant current charging at 0.05C for 180 minutes, constant current charging at 0.2C to 3.95V, followed by a second vacuum sealing. Then, it was further charged at a constant current of 0.2C to 4.2V, left to stand at room temperature for 24 hours, and finally discharged at a constant current of 0.2C to 3.0V to obtain a LiNi alloy. 0.5 Co 0.2 Mn 0.3 O2 / artificial graphite lithium-ion battery.

[0160] Comparative Examples 1-7

[0161] This embodiment is used to compare and illustrate the non-aqueous electrolyte and battery methods disclosed in this invention, including most of the operational steps in Example 1, with the following differences:

[0162] In the preparation of the non-aqueous electrolyte, additives are added in the mass percentages shown in Comparative Examples 1 to 7 in Tables 1 to 4.

[0163] Performance testing

[0164] The lithium-ion batteries prepared in Examples 1-14 and Comparative Examples 1-7 were subjected to the following performance tests: High-temperature storage performance test

[0165] The formed lithium-ion battery was charged at room temperature with a constant current of 1C to 4.2V, then charged with a constant current and constant voltage until the current dropped to 0.05C. It was then discharged at a constant current of 1C to 3.0V. The initial discharge capacity and initial battery volume were measured. The battery was then fully charged and stored at 60℃ for 30, 60, and 90 days, respectively. Afterward, it was discharged at 1C to 3V, and the retention and recovery capacities were measured. The calculation formulas are as follows:

[0166] Battery capacity retention rate (%) = Retained capacity / Initial capacity × 100%;

[0167] Battery capacity recovery rate (%) = Recovered capacity / Initial capacity × 100%.

[0168] 1. Fill in Table 1 with the test results obtained from Examples 1 to 8 and Comparative Examples 1 to 4.

[0169] Table 1

[0170]

[0171] Comparing the test results of Examples 1-8 and Comparative Examples 1-4, it can be seen that, compared with traditional vinylene carbonate (VC), vinyl sulfate (DTD) and 1,3-propanesulfonate lactone (PS), using the compound shown in structural formula 1 provided in this application as an additive can more significantly improve the storage performance of lithium-ion batteries at high temperatures, indicating that the passivation film formed by the compound shown in structural formula 1 has better high-temperature stability.

[0172] 2. Fill the test results obtained from Examples 2 and 9-13 into Table 2.

[0173] Table 2

[0174]

[0175] Comparing the test results of Examples 2 and 9-13, it can be seen that as the amount of compound shown in Structural Formula 1 increases, the high-temperature storage performance of lithium-ion batteries first increases and then decreases. In particular, when the amount of compound shown in Structural Formula 1 is between 0.5% and 5%, the lithium-ion battery has the best high-temperature storage performance.

[0176] 3. Fill the test results obtained from Example 2, Example 14, Comparative Example 3 and Comparative Example 5 into Table 3.

[0177] Table 3

[0178]

[0179] Comparing the test results of Examples 2, 14, 3, and 5, it can be seen that compared with the traditional combination of vinylene carbonate (VC) and vinyl sulfate (DTD) additives, or the addition of vinyl sulfate (DTD) alone, or the addition of the compound shown in Structural Formula 1 alone, the combination of the compound shown in Structural Formula 1 provided in this application with vinyl sulfate (DTD) further improves the battery performance, indicating that the passivation film formed by the co-decomposition of the compound shown in Structural Formula 1 and vinyl sulfate (DTD) has better high-temperature stability.

[0180] 4. Fill the test results obtained from Example 3, Example 6, Comparative Example 6 and Comparative Example 7 into Table 4.

[0181] Table 4

[0182]

[0183] Comparing the test results of Examples 3 and 6 with those of Comparative Examples 6 and 7, it can be seen that only when the compound shown in Structural Formula 1 has two or more cyclic substituents can a cross-linked structure film with strong integrity and stable structure be formed, thereby forming a passivation film with stable high-temperature performance.

[0184] 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. A nonaqueous electrolyte, characterized by comprising: The solvent, the electrolyte salt, and the compound shown in structural formula 1 are included. Structural formula 1 wherein z is selected from 0 or 1; m, c are each independently selected from any natural number from 1 to 3; p is selected from any natural number from 0 to 3; When z = 0, n = 1; when z = 1, n = 0 or 1; E1, E2 are each independently selected from a five-membered ring carbonate group and derivatives thereof, a five-membered ring sulfite group and derivatives thereof, a five-membered ring sulfate group and derivatives thereof, a five-membered ring sulfonate group and derivatives thereof, or a five-membered ring sulfinic acid ester group and derivatives thereof, and E1, E2 can be the same or different; A is selected from halogen, lithium, sodium, C1-C4 halogenated hydrocarbon group, cyclic carbonate group and derivatives thereof, cyclic sulfite group and derivatives thereof, cyclic sulfate group and derivatives thereof, cyclic sulfonate group and derivatives thereof, or cyclic sulfinic acid ester group and derivatives thereof.

2. The nonaqueous electrolyte according to claim 1, characterized by E1, E2 are each independently selected from one of the following groups: 、 、 、 、 。 3. The nonaqueous electrolyte according to claim 1, characterized by m, c are the same, and E1, E2 are the same.

4. The nonaqueous electrolyte according to claim 1, characterized by When z = 0, A is selected from a cyclic carbonate group and derivatives thereof, a cyclic sulfite group and derivatives thereof, a cyclic sulfate group and derivatives thereof, a cyclic sulfonate group and derivatives thereof, or a cyclic sulfinic acid ester group and derivatives thereof; When z = 1, A is selected from halogen, lithium, sodium, C1-C4 halogenated hydrocarbon group, cyclic carbonate group and derivatives thereof, cyclic sulfite group and derivatives thereof, cyclic sulfate group and derivatives thereof, cyclic sulfonate group and derivatives thereof, or cyclic sulfinic acid ester group and derivatives thereof.

5. The nonaqueous electrolyte according to claim 1 or 4, wherein A is selected from a group shown in structural formula 2 or structural formula 3: Structural formula 2 wherein a, b are natural numbers and a + b = 1 or 2; d = 1 or 2, when d = 2, Y is a sulfur atom; when d = 1, Y is a sulfur atom or a carbon atom; Structural formula 3 wherein i, k are natural numbers and i + k = 1 or 2 or 3, j = 1 or 2.

6. The nonaqueous electrolyte according to claim 1, wherein The compound shown in structural formula 1 is selected from one or more of the following compounds: 。 7. The nonaqueous electrolyte according to claim 1, wherein The addition amount of the compound shown in structural formula 1 is 0.05-10% based on the total mass of the non-aqueous electrolyte being 100%.

8. The nonaqueous electrolyte according to claim 1, wherein The electrolyte salt is selected from at least one of LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, Li2B 10 Cl 10 , a lithium salt of a lower aliphatic carboxylic acid.

9. The nonaqueous electrolyte according to claim 1, wherein The non-aqueous electrolyte further includes an auxiliary additive, and the auxiliary additive includes at least one of a cyclic sulfate compound, a sulfonic acid lactone compound, a cyclic carbonate compound, an unsaturated phosphate compound, and a nitrile compound.

10. The nonaqueous electrolyte according to claim 9, wherein The cyclic sulfate compound is selected from at least one of vinyl sulfate, propylene sulfate, or methyl vinyl sulfate; The sulfonic acid lactone compound is selected from at least one of 1,3-propane sulfonic acid lactone, 1,4-butane sulfonic acid lactone, or 1,3-propylene sulfonic acid lactone; The cyclic carbonate compound is selected from at least one of vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, or a compound shown in structural formula 4, Structural formula 4 In the structural formula 4, R 21 , R 22 , R 23 , R 24 , R 25 , R 26 are each independently selected from one of a hydrogen atom, a halogen atom, a C1-C5 group; The unsaturated phosphate compound is selected from at least one of the compounds shown in structural formula 5: Structural formula 5 In the structural formula 5, R 31 , R 32 , R 32 are each independently selected from a C1-C5 saturated hydrocarbon group, an unsaturated hydrocarbon group, a halogenated hydrocarbon group, -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 , R 32 , R 33 at least one of which is an unsaturated hydrocarbon group; The nitrile compound includes one or more of butanedinitrile, pentanedinitrile, ethylene glycol bis(propionitrile) ether, hexanetristitnile, hexanedinitrile, heptanedinitrile, octanedinitrile, nonanedinitrile, decanedinitrile.

11. A battery, characterized by The non-aqueous electrolyte as claimed in any one of claims 1-10 is included in a positive electrode, a negative electrode, and the like.

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