Compounds, methods of making the same, and uses thereof

Abstract

This application provides a compound of formula (I), including an electrolyte additive of the compound, an electrolyte including the electrolyte additive, and a battery including the electrolyte. The compound provided in this application introduces a silicon-based structure on a calix[4] aromatic structure, which, by virtue of its amphiphilic properties, quickly achieves compatibility with the electrode-electrolyte interface, balances various internal characteristics of the battery cell, amplifies the dehydration and deacidification effects, promotes the stability of its CEI / SEI properties, and stabilizes the positive electrode material structure, thereby reducing and stabilizing the internal impedance changes of the battery cell and improving the battery cell performance. Experimental results show that, after the compound provided in this application is added to the electrolyte, compared with calix[4] aromatics and silicon-based compounds as additives, it improves the initial efficiency of the battery, significantly reduces the SEI interface resistance, and improves the rate retention rate.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a compound, its preparation method, and its application. Background Technology

[0002] With the widespread use of electrochemical devices, such as lithium-ion batteries, in various electronic products, users are placing increasingly higher demands on the cycle performance of batteries.

[0003] LiPF6 electrolyte salt is widely used in commercial lithium-ion batteries due to its high ionic conductivity and excellent electrochemical stability. However, its stability in organic solvents is poor. The highly reactive acidic substances such as POF3, PF5, and HF produced by hydrolysis can cause irreversible damage to the solid electrolyte interface (SEI) / cathode electrolyte interface (CEI), leading to a sharp increase in internal impedance and cell degradation. Current technologies generally improve interfacial stability by adding additives to the electrolyte, but their effect on improving battery performance is limited. Summary of the Invention

[0004] In view of this, the present invention provides a compound, its preparation method and its application. The compound provided in this application can be added to the electrolyte of a lithium-ion battery as an additive, which can quickly make the electrode-electrolyte interface compatible, balance the various characteristics inside the cell, amplify the water removal and acid removal effect, promote its stable CEI / SEI properties, thereby reducing and stabilizing the internal impedance change of the cell and improving the cell performance.

[0005] This application provides a compound of formula (I):

[0006] Formula (I);

[0007] R1, R2 and R3 are independently selected from alkyl or at least one substituent-substituted alkyl, alkenyl or at least one substituent-substituted alkenyl, alkynyl or at least one substituent-substituted alkynyl, ester or at least one substituent-substituted ester, alkylamino or at least one substituent-substituted alkylamino, nitrogen-containing heterocyclic or at least one substituent-substituted nitrogen-containing heterocyclic, phosphate ester or at least one substituent-substituted phosphate ester, borate ester or at least one substituent-substituted borate ester, sulfonate ester or at least one substituent-substituted sulfonate ester, alkylaminocarbonyl or at least one substituent-substituted alkylaminocarbonyl, alkyl or at least one substituent-substituted ketone;

[0008] The substituents are independently selected from halogens, alkyl, alkenyl, alkynyl, alkylsilyl, or alkylsiloxy groups.

[0009] In some specific implementations, R1, R2, and R3 are not all alkyl groups.

[0010] In some specific implementations, R1, R2, and R3 are independently selected from alkyl, alkynyl, halogen-substituted alkyl, alkylsiloxy-substituted alkyl, alkylsilyl-substituted phosphate ester, alkylsilyl-substituted borate ester, or oxazolidinone.

[0011] In some specific implementations, the compound has R C-1 ~ R C-9 The structure described:

[0012] R C-1 ; R C-2 ; R C-3 ; R C-4 ; R C-5 ; R C-6 ; R C-7 ; R C-8 ; R C-9 .

[0013] This application also provides an electrolyte additive, including the compounds described in the above technical solutions.

[0014] In some specific implementations, the electrolyte additive may further include one or more of the following: vinylene carbonate, fluoroethylene carbonate, 1,3-propanesulfonate lactone, vinyl sulfate, diphenyl carbonate, toluene carbonate, acrylate, succinic anhydride, succinic anhydride, and adiponitrile.

[0015] In some specific implementations, the electrolyte additives include fluoroethylene carbonate and vinylene carbonate;

[0016] The mass ratio of the compound, vinylene carbonate, and fluorovinyl carbonate is 0.1~3:0.5~1.5:0.5~1.5.

[0017] This application also provides an electrolyte, comprising an electrolyte, a solvent, and the additives described in the above technical solution.

[0018] In some specific implementations, the mass concentration of the electrolyte is 5wt%~20wt%;

[0019] The amount of the additive added is 0.5wt% to 5wt% of the total amount of electrolyte and solvent.

[0020] This application also provides a battery, including the electrolyte described in the above technical solution.

[0021] The compound provided in this application introduces a silicon-based structure onto a calix[4] aromatic structure. Utilizing the amphiphilic properties of this compound, it rapidly integrates with the electrode-electrolyte interface, balancing various internal characteristics of the battery cell, amplifying the dehydration and deacidification effects, promoting stable CEI / SEI properties, and stabilizing the cathode material structure. This reduces and stabilizes the internal impedance changes of the battery cell, thereby improving its performance. Experimental results show that, compared to calix[4] aromatics and silicon-based compounds as additives, the compound provided in this application, when added to the electrolyte, improves the initial efficiency of the battery, significantly reduces the SEI interface resistance, and increases the rate retention rate. Detailed Implementation

[0022] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0023] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0024] The term "halogen" stands for fluorine, chlorine, bromine, and iodine;

[0025] The term "alkyl" represents a saturated straight-chain or branched hydrocarbon group having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylethyl, 1-ethylpropyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, etc. 2-Methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, and 1-ethyl-2-methylpropyl;

[0026] The term "alkenyl" represents an unsaturated straight-chain or branched hydrocarbon group having 2 or 3 to 6 carbon atoms and a double bond at any desired position, such as C2-C6-alkenyl groups like vinyl, 1-propenyl, 2-propenyl, 1-methylvinyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-methyl-1-butenyl, 2-methyl-1-butenyl, 3- Methyl-1-butenyl, 1-methyl-2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 1-methyl-3-butenyl, 2-methyl-3-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1,2-dimethyl-1-propenyl, 1,2-dimethyl-2-propenyl, 1-ethyl-1-propenyl, 1-ethyl-2-propenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-methyl-1-pentenyl, 2 -Methyl-1-pentenyl, 3-methyl-1-pentenyl, 4-methyl-1-pentenyl, 1-methyl-2-pentenyl, 2-methyl-2-pentenyl, 3-methyl-2-pentenyl, 4-methyl-2-pentenyl, 1-methyl-3-pentenyl, 2-methyl-3-pentenyl, 3-methyl-3-pentenyl, 4-methyl-3-pentenyl, 1-methyl-4-pentenyl, 2-methyl-4-pentenyl, 3-methyl-4-pentenyl, 4-methyl-4-pentenyl, 1,1-dimethyl-2-butenyl, 1,1- Dimethyl-3-butenyl, 1,2-dimethyl-1-butenyl, 1,2-dimethyl-2-butenyl, 1,2-dimethyl-3-butenyl, 1,3-dimethyl-1-butenyl, 1,3-dimethyl-2-butenyl, 1,3-dimethyl-3-butenyl, 2,2-dimethyl-3-butenyl, 2,3-dimethyl-1-butenyl, 2,3-dimethyl-2-butenyl, 2,3-dimethyl-3-butenyl, 3,3-dimethyl-1-butenyl, 3,3- Dimethyl-2-butenyl, 1-ethyl-1-butenyl, 1-ethyl-2-butenyl, 1-ethyl-3-butenyl, 2-ethyl-1-butenyl, 2-ethyl-2-butenyl, 2-ethyl-3-butenyl, 1,1,2-trimethyl-2-propenyl, 1-ethyl-1-methyl-2-propenyl, 1-ethyl-2-methyl-1-propenyl or 1-ethyl-2-methyl-2-propenyl;

[0027] The term "alkynyl" represents a straight-chain or branched hydrocarbon group having 2 to 6 carbon atoms and a triple bond at any desired position, such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-methyl-2-propynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-methyl- 2-Butynyl, 1-Methyl-3-butynyl, 2-Methyl-3-butynyl, 3-Methyl-1-butynyl, 1,1-Dimethyl-2-propynyl, 1-Ethyl-2-propynyl, 1-Hexynyl, 2-Hexynyl, 3-Hexynyl, 4-Hexynyl, 5-Hexynyl, 1-Methyl-2-pentynyl, 1-Methyl-3-pentynyl, 1-Methyl-4-pentynyl, 2-Methyl-3-pentynyl, 2-Methyl-4-pentynyl, 3-Methyl-1- Pentynyl, 3-methyl-4-pentynyl, 4-methyl-1-pentynyl, 4-methyl-2-pentynyl, 1,1-dimethyl-2-butynyl, 1,1-dimethyl-3-butynyl, 1,2-dimethyl-3-butynyl, 2,2-dimethyl-3-butynyl, 3,3-dimethyl-1-butynyl, 1-ethyl-2-butynyl, 1-ethyl-3-butynyl, 2-ethyl-3-butynyl and 1-ethyl-1-methyl-2-propynyl;

[0028] The term "alkylamino" refers to (as described above) a straight-chain or branched alkyl group having 1 to 6 carbon atoms bonded to the main structure via an amino group (-NH-).

[0029] The term "alkylaminocarbonyl" represents (as described above) an alkylamino group that is bonded to the main structure via a carbonyl group (-CO-);

[0030] The term "alkyl carbonyl" refers to (as described above) a straight-chain or branched alkyl group having 1 to 6 carbon atoms, which is bonded to the main structure via a carbonyl group (-CO-);

[0031] The term "ester group" refers to (as described above) a straight-chain or branched alkyl group having 1 to 6 carbon atoms bonded to the main structure via a carbonyl group (-CO-) and an oxygen atom (-O-).

[0032] The term "phosphate ester group" refers to the phosphate ester group (PO4-) bonded to the main structure;

[0033] The term "boronate group" indicates that the borate ester group (BO3-) is bonded to the main structure.

[0034] The term "sulfonate group" indicates that the sulfonate group (SO2-) is bonded to the main structure;

[0035] The term "nitrogen-containing heterocyclic group" refers to a nitrogen-containing heterocyclic group bonded to the main structure via -N- bonds. In addition to C and N, it can also contain a group of heteroatoms composed of oxygen and sulfur as ring members. For example, it can be a 5-membered nitrogen-containing heterocyclic group containing one to four nitrogen atoms or one to three nitrogen atoms and one sulfur or oxygen atom. Nitrogen-containing heterocyclic groups can also be nitrogen-containing six-membered heterocyclic groups, including carbon atoms and one to five nitrogen atoms. In addition, it can also contain one sulfur atom or oxygen atom as a ring member, etc.

[0036] The term "alkylsiloxy" refers to (as described above) a straight-chain or branched alkyl group having 1 to 6 carbon atoms, which is bonded to the main structure via siloxy groups (-Si-O-).

[0037] The term "alkylsilyl" refers to (as described above) a straight-chain or branched alkyl group having 1 to 6 carbon atoms bonded to the main structure via a silyl group (-Si-).

[0038] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0039] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and is not intended to limit the scope of the invention unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0040] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0041] This application provides a compound of formula (I):

[0042] Formula (I);

[0043] R1, R2 and R3 are independently selected from alkyl or at least one substituent-substituted alkyl, alkenyl or at least one substituent-substituted alkenyl, alkynyl or at least one substituent-substituted alkynyl, ester or at least one substituent-substituted ester, alkylamino or at least one substituent-substituted alkylamino, nitrogen-containing heterocyclic or at least one substituent-substituted nitrogen-containing heterocyclic, phosphate ester or at least one substituent-substituted phosphate ester, borate ester or at least one substituent-substituted borate ester, sulfonate ester or at least one substituent-substituted sulfonate ester, alkylaminocarbonyl or at least one substituent-substituted alkylaminocarbonyl, alkylcarbonyl or at least one substituent-substituted alkylcarbonyl;

[0044] The substituents are independently selected from halogens, alkyl groups, alkenyl groups, alkynyl groups, alkylsiloxy groups, or alkylsilyl groups.

[0045] This application introduces a silicon-based structure into a compound of formula (I) on a calix[4] aromatic structure, which has both a calix[4] aromatic structure and a silicon-based structure. When added as an additive to the electrolyte of a lithium-ion battery, it can quickly become compatible with the electrode-electrolyte interface, balance the various characteristics of the cell, amplify the water and acid removal effect, promote its stable CEI / SEI properties, thereby reducing and stabilizing the internal impedance change of the cell and improving the cell performance.

[0046] In some specific implementations, R1, R2, and R3 are not all alkyl groups. In some specific implementations, at least one of R1, R2, and R3 is selected from alkynyl or an alkynyl group substituted with at least one substituent, ester group or an ester group substituted with at least one substituent, alkylamino or an alkylamino group substituted with at least one substituent, nitrogen-containing heterocyclic group or a nitrogen-containing heterocyclic group substituted with at least one substituent, phosphate ester group or a phosphate ester group substituted with at least one substituent, borate ester group or a borate ester group substituted with at least one substituent.

[0047] In some specific implementations, R1, R2, and R3 are independently selected from alkyl, alkynyl, halogen-substituted alkyl, alkylsiloxy-substituted phosphate ester, alkylsilyl-substituted phosphate ester, alkylsilyl-substituted borate ester, or oxazolidinone, preferably methyl, ethyl, acetate, trimethylsiloxy acetate, ethynyl, trifluoromethyl, oxazolidin-2-one, trimethylsilyl phosphate, trimethylsilyl borate ester, etc.

[0048] In some specific implementations, the compound has R C-1 ~ R C-9 The structure described:

[0049] R C-1 ; R C-2 ; RC-3 ; R C-4 ; R C-5 ; R C-6 ; R C-7 ; R C-8 ; R C-9 .

[0050] This application does not impose any particular limitation on the preparation method of the compound shown in formula (I), and it can be prepared according to the following method:

[0051] The compound shown in Formula A reacts with the calix[4]arene shown in Formula B to obtain the compound shown in Formula (I). The reaction process is as follows:

[0052]

[0053] This application uses the compound shown in formula A as a starting material to prepare the compound shown in formula (I). This application does not have any special restrictions on its source; it can be purchased on the market and can be prepared according to the following method:

[0054] The compound shown in formula C, under the action of a chlorinating reagent, yields the compound shown in formula A, and the reaction process is as follows:

[0055]

[0056] The compound represented by Formula C is a silane containing substituents R1, R2, and R3, wherein R1, R2, and R3 have the same definitions as above and will not be repeated here. This application does not impose any special restrictions on the source of the compound represented by Formula C; it can be purchased commercially.

[0057] The compound shown in Formula C reacts with hydrochloric acid and a chlorinating agent to obtain the compound shown in Formula A. This application does not have any special restrictions on the chlorinating agent, which can be zinc chloride, thionyl chloride, phosphorus chloride, etc. This application does not have any special restrictions on the reaction steps, parameters, conditions, etc., and any method known to those skilled in the art is acceptable. The applicant found that although trimethylsilyl-based additives can form a film on the negative electrode in secondary batteries, they cannot truly protect the negative electrode. They can reduce internal resistance in the early stage but affect the lifespan in the later stage. They are effective in removing water and acid, but their effect on improving the performance of the battery cell is not obvious. Therefore, they are introduced into the molecular structure of calix[4] aromatic hydrocarbons in order to improve the performance of the battery cell.

[0058] After obtaining the compound shown in Formula A, it is reacted with the calix[4]arene shown in Formula B to obtain the compound shown in Formula (I). Specifically, the calix[4]arene shown in Formula B is p-tert-butylcalix[4]arene, which can be purchased on the market. As the third generation of supramolecular host after crown ethers and cyclodextrins, calixarene has the characteristics of easy modification (simple synthesis), adjustable cavity size, and recognition of ionic or molecular guests, and has been widely used in various fields. As the only fluid in the battery cell, the electrolyte has a phase interface with the positive and negative electrodes and the separator. One side of the electrode interface film is tightly bonded to the electrode, and the other side is well mixed with the solvated lithium ions. Its properties change gradually from polar to nonpolar, so as to achieve amphiphilicity with the electrode and electrolyte and complete the sieving of lithium ions and solvent. Calico[4]aromatics has the characteristics of amphiphilic compounds, which can be used to improve the compatibility between electrolyte and electrode materials. Its atomizing groups form a new surface on one side, coordinate and encapsulate ions, and polymerize to form a continuous thin layer, which conforms to the formation mechanism of electrode interface film. Its hydrophilic end can capture a small amount of H2O and HF, and isolate them outside the interface film. However, the resulting battery cell has a high interface resistance. This application introduces a silicon-based structure into the calix[4]aromatics structure, which can further reduce the interface resistance and thus improve the battery cell performance.

[0059] In some specific implementations, the compound shown in Formula B and the basic compound are first dissolved in a reaction medium, and then the compound shown in Formula A and a catalyst are added to carry out the reaction. In some specific implementations, the basic compound includes, but is not limited to, potassium carbonate, sodium carbonate, sodium sulfite, sodium acetate, potassium acetate, etc., preferably potassium carbonate. In some specific implementations, the catalyst includes, but is not limited to, KI, Al₂O₃, Al₂O₃-SiO₂, ZnS, etc., preferably KI. In some specific implementations, the reaction medium includes, but is not limited to, acetone, benzene, toluene, dichloromethane, etc., preferably acetone. In some specific implementations, the molar ratio of the compound shown in Formula B to the compound shown in Formula A is preferably 1:4 to 5; the mass ratio of the compound shown in Formula B to the basic compound is preferably 1 to 10:10, more preferably 3 to 9:10; the mass-volume ratio of the compound shown in Formula B to the reaction medium is preferably 1 g to 10 g: 200 mL to 500 mL, more preferably 2 g to 8 g: 250 mL to 450 mL; and the mass ratio of the compound shown in Formula B to the catalyst is preferably 1 g to 10 g: 0.1 g to 0.5 g, more preferably 1 g to 10 g: 0.2 g to 0.4 g.

[0060] After thorough mixing, the reaction system is heated to allow for reaction. In some specific implementations, the reaction temperature is preferably 70℃~100℃, more preferably 80℃~90℃; the reaction time is preferably 30h~60h, more preferably 35h~55h. After the reaction is complete, the resulting reaction system is cooled to room temperature, filtered, and then aged in an aging machine. After filtration again, the filter residue is recrystallized to obtain the compound shown in formula (I). In some specific implementations, the aging agent is selected from methanol, ethanol, isopropanol, acetone, or acetonitrile, preferably methanol. In some specific implementations, the aging time is preferably 10h~30h, more preferably 15h~25h. In some specific implementations, the recrystallization solvent includes, but is not limited to, anhydrous ethanol, methanol, isopropanol, acetone, acetonitrile, etc., preferably anhydrous ethanol.

[0061] This application also provides an electrolyte additive, including the compounds described in the above technical solutions.

[0062] In some specific implementations, the electrolyte additive further includes one or more of the following: vinylene carbonate, fluoroethylene carbonate, 1,3-propanesulfonate lactone, vinyl sulfate, diphenyl carbonate, toluene carbonate, acrylate nitrile, succinic anhydride, succinic anhydride, and adiponitrile, preferably including fluoroethylene carbonate (FEC) and vinylene carbonate (VC). In some specific implementations, the mass ratio of the compound, vinylene carbonate, and fluoroethylene carbonate is 0.1~3:0.5~1.5:0.5~1.5, preferably 0.5~2.5:1:1.

[0063] This application also provides an electrolyte, comprising an electrolyte, a solvent, and the additives described in the above-described technical solutions. In some specific implementations, the electrolyte can be a lithium-ion battery electrolyte, in which case the electrolyte comprises a lithium salt electrolyte, an organic solvent, and the additives described in the above-described solutions. In some specific implementations, the lithium salt electrolyte includes, but is not limited to, one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP), preferably lithium hexafluorophosphate. In some specific implementations, the concentration of the lithium salt electrolyte is 10wt%~20wt%, preferably 12wt%~15wt%. In some specific implementations, the organic solvent includes, but is not limited to, one or more of ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, ethylene carbonate, ethyl propionate, ethyl acetate, methyl acetate, dimethyl acetate, methyl butyrate, and n-propyl acetate, preferably a mixture of ethylene carbonate (EC) and methyl ethyl carbonate (EMC), wherein the mass ratio of EC to EMC is preferably 20~40:40~60, more preferably 25~35:45:55. In some specific implementations, the amount of the additive added is 0.5wt%~5wt% of the total amount of electrolyte and solvent, preferably 1wt%~4wt%, more preferably 2wt%~3wt%.

[0064] In some specific implementations, the electrolyte is sodium hexafluorophosphate, and the solvent is a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC). The mass ratio of EC to EMC is preferably 20-40:40-60, more preferably 25-35:45:55. The concentration of the electrolyte is 10wt%-20wt%, preferably 12wt%-15wt%. The additive includes the compounds described in the above technical solutions, vinylene carbonate, and fluoroethylene carbonate, with a mass ratio of 0.1-3:0.5-1.5:0.5-1.5, preferably 0.5-2.5:1:1. The amount of additive added is 0.5wt%-5wt% of the total electrolyte and solvent, preferably 1wt%-4wt%, more preferably 2wt%-3wt%.

[0065] In some specific implementations, the electrolyte can be a sodium-ion battery electrolyte. In this case, the electrolyte includes a sodium salt electrolyte, an organic solvent, and the additives described in the above-mentioned scheme. Similar to lithium-ion battery electrolytes, the difference of sodium-ion battery electrolytes is that the electrolyte is a sodium salt. The sodium salt can be selected from sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium dioxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP), etc., and this application does not have any special restrictions on this.

[0066] This application does not impose any particular limitation on the preparation method of the electrolyte, which can be prepared according to the following method:

[0067] Solvent, electrolyte, and additives are mixed to obtain electrode solution.

[0068] Specifically, this application can first mix the solvent and electrolyte evenly, and then add the additive and mix evenly. This application does not have special restrictions on the process parameters of each step, as long as the substances are fully dissolved and mixed evenly.

[0069] This application also provides a battery, including the electrolyte described in the above-described technical solution. Specifically, the battery can be a lithium-ion battery, which includes a positive electrode, a negative electrode, a separator separating the positive and negative electrode, and the electrolyte described in the above-described technical solution.

[0070] The lithium-ion battery includes a positive electrode sheet, which comprises a positive current collector and a positive active material layer formed on the positive current collector. In some specific implementations, the positive current collector can be a metal foil, including but not limited to aluminum foil, nickel foil, stainless steel, etc. For example, the positive current collector can be aluminum foil. A positive active material layer is disposed on the surface of the positive current collector, which includes a positive electrode material, an optional conductive agent, and an optional binder. In some specific implementations, the mass ratio of the positive electrode material, conductive agent, and binder is 90~98:1~5:1~5, preferably 92~95:2~4:1.5~2. In some specific implementations, the positive electrode material includes but is not limited to LiFePO4, LiCoO2, and LiNi. x Co y Mn 1-x-y O2, LiMn2O 4、 Na (Ni 0.5 Mn0.5 ) x Fe 1-x O2, Na3V2(PO4)3, Na2FeFe(CN)6, etc., can be one or more of these. When the positive electrode material is a mixture of multiple specific substances, this application does not impose excessive limitations on the proportions between the specific substances. In some specific implementations, the conductive agent includes, but is not limited to, carbon black, hard carbon, graphite, carbon nanotubes, graphene, silver powder, nickel powder, tin oxide, conductive titanium dioxide, etc., and can be one or more of these. When the conductive agent is a mixture of multiple specific substances, this application does not impose excessive limitations on the proportions between the specific substances. The binder includes, but is not limited to, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, polyamide, lithium polyacrylate, methacrylate, sodium polymethyl cellulose, aluminum dihydrogen phosphate, etc., and can be one or more of these. When the binder is a mixture of multiple specific substances, this application does not impose excessive limitations on the proportions between the specific substances.

[0071] This application does not impose any particular limitations on the preparation method of the positive electrode sheet. The positive electrode material, optional conductive agent, and optional binder are mixed uniformly in a solvent, such as N-methylpyrrolidone (NMP), and then coated onto the positive electrode current collector in an optional manner. After drying, the positive electrode sheet is obtained. Further, the drying process may include rolling, slicing, etc., which are not particularly limited in this application.

[0072] The lithium-ion battery includes a negative electrode sheet, which includes a negative current collector and a negative active material layer formed on the negative current collector. In some specific implementations, the negative current collector can be a metal foil, including but not limited to aluminum foil, nickel foil, stainless steel, etc. For example, the negative current collector can be aluminum foil. A negative active material layer is disposed on the surface of the negative current collector, which includes a negative electrode material, an optional conductive agent, an optional binder, and an optional thickener. In some specific implementations, the mass ratio of the negative electrode material, conductive agent, binder, and thickener is 90~98:0.5~2:0.5~3:1~5, preferably 92~97:0.7~1.5:0.8~1.5:1~2. In some specific implementations, the negative electrode material includes but is not limited to graphite, hard carbon, soft carbon, lithium titanate, silicon-based composite materials, and tin-based composite materials, and can be one or more of these. When the negative electrode material is a mixture of multiple specific substances, this application does not impose excessive limitations on the proportions between the specific substances. In some specific implementations, the conductive agent includes, but is not limited to, carbon black, hard carbon, graphite, carbon nanotubes, graphene, silver powder, nickel powder, tin oxide, conductive titanium dioxide, etc., and can be one or more of these. When the conductive agent is a mixture of multiple specific substances, this application does not impose excessive restrictions on the proportions between the specific substances. The binder includes, but is not limited to, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC-Na), polyacrylic acid (PAA), polytetrafluoroethylene (PTFE), polyimide (PI), etc., and can be one or more of these. When the binder is a mixture of multiple specific substances, this application does not impose excessive restrictions on the proportions between the specific substances. The thickener includes, but is not limited to, sodium carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC-Na), polyacrylic acid (PAA), polytetrafluoroethylene (PTFE), polyimide (PI), etc., and can be one or more of these. When the thickener is a mixture of multiple specific substances, this application does not impose excessive restrictions on the proportions between the specific substances.

[0073] This application does not impose any particular restrictions on the preparation method of the negative electrode sheet. The negative electrode material, optional conductive agent, optional binder, and optional thickener are mixed evenly in a solvent, such as deionized water, and then coated onto a negative electrode current collector in an optional manner. After drying, the negative electrode sheet is obtained. Further, the drying process may include rolling, slicing, etc., which are not particularly limited in this application.

[0074] In some specific implementations, the diaphragm includes, but is not limited to, glass fiber microporous membranes, polyester microporous membranes, polyethylene microporous membranes, polypropylene microporous membranes, polytetrafluoroethylene microporous membranes, ceramic-coated diaphragms, etc.

[0075] In some specific implementations, the electrode liquid is described above, with the addition of compound additive of formula (I), which can quickly make the electrode-electrolyte interface compatible, balance the various characteristics inside the cell, amplify the water and acid removal effect, promote its stable CEI / SEI properties, stabilize the positive electrode material structure, thereby reducing and stabilizing the internal impedance change of the cell and improving the cell performance.

[0076] This application describes how a positive electrode, a separator, and a negative electrode are stacked in sequence to obtain a cell assembly, which is then sealed in an aluminum-plastic bag and injected with electrolyte. After processes such as encapsulation, settling, and formation, a lithium-ion battery is obtained.

[0077] The following examples further illustrate the compounds provided by the present invention, their preparation methods, and their applications.

[0078] Example 1

[0079] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution, followed by 5.18 g (30.8 mmol) of dimethylchlorosilyl acetate and 0.2 g of KI. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The solid was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-1 The compound shown was obtained in a yield of 80% and a purity of 98.5%, with a yield of 7.25 g (6.15 mmol).

[0080] R c-1 .

[0081] Example 2

[0082] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution. Then, 7.41 g (30.8 mmol) of 2-((trimethylsilyl)oxy)chlorodimethylsilyl acetate and 0.2 g of KI were added. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The mixture was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-2 The compound shown was obtained in a yield of 80% and a purity of 98%. 7.58 g (6.15 mmol) of the compound was obtained.

[0083] R c-2 .

[0084] Example 3

[0085] 5 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and a small amount of 10 g of anhydrous potassium carbonate dissolved in water were added to 300 mL of acetone solution. Then, 4.52 g (30.8 mmol) of dichloroethyl(ethynyl)silane and 0.2 g of KI were added. After mixing evenly, the mixture was rapidly heated to 60 °C and refluxed for 36 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The solid was then aged for 20 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-3 The compound shown was obtained in a yield of 77% and a purity of 98%.

[0086] R c-3 .

[0087] Example 4

[0088] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution, followed by 4.39 g (30.8 mmol) of chlorotriethynylsilane and 0.2 g of KI. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The solid was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-4 The compound shown was obtained in a yield of 80% and a purity of 99%. 7.33 g (6.15 mmol) of the compound was obtained.

[0089] R c-4 .

[0090] Example 5

[0091] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution. Then, 6.98 g (30.8 mmol) of chloro(ethynyl)bis(trifluoromethyl)silane and 0.2 g of KI were added. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The mixture was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-5 The compound shown was obtained in a yield of 76% and a purity of 98%. 8.96 g (5.86 mmol) was obtained.

[0092] R c-5 .

[0093] Example 6

[0094] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution. Then, 5.16 g (30.8 mmol) of 3-(chlorodimethylsilyl)oxazolidine-2-one and 0.2 g of KI were added. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The solid was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-6 The compound shown was obtained in a yield of 8.06 g (6.24 mmol), with a purity of 99%.

[0095] R c-6 .

[0096] Example 7

[0097] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution, followed by 10.31 g (30.8 mmol) of dichlorodimethylsilylbis(trimethylsilyl)phosphate and 0.25 g of KI. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The solid was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-7 The compound shown was obtained in a yield of 85% and a purity of 98%.

[0098] R c-7 .

[0099] Example 8

[0100] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution, followed by 9.20 g (30.8 mmol) of dichlorodimethylsilylbis(trimethylsilyl)boronic acid ester and 0.2 g of KI. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The solid was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-8 The compound shown was obtained in a yield of 83% and a purity of 99%.

[0101] R c-8 .

[0102] Example 9

[0103] 7 g (7.7 mmol) of p-tert-butylcalix[4] aromatic hydrocarbon and 10 g of potassium carbonate dissolved in a small amount of water were added to 300 mL of acetone solution. Then, 4.48 g (30.8 mmol) of 1-chloro-N,N-diethyl-1,1-dimethylsilylamine and 0.2 g of KI were added. After mixing evenly, the mixture was rapidly heated to 80 °C and refluxed for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and an appropriate amount of methanol was added to the obtained solid. The mixture was then aged for 24 h and filtered again. The residue was recrystallized using anhydrous ethanol to obtain formula R. c-9 The compound shown was obtained in a yield of 80% and a purity of 98.5%.

[0104] R c-9 .

[0105] Examples 10-19

[0106] Additives were prepared by mixing the compounds prepared in Examples 1-9 with FEC and VC at a mass ratio of 0.5:1:1.

[0107] Comparative Examples 1-9

[0108] Additives were prepared by mixing the silicon compounds used in Examples 1-9 with FEC and VC at a mass ratio of 0.5:1:1.

[0109] Comparative Example 10

[0110] An additive was prepared by mixing p-tert-butylcalix[4] aromatics with FEC and VC in a mass ratio of 0.5:1:1.

[0111] Comparative Example 11

[0112] The additive was prepared by mixing FEC and VC in a 1:1 mass ratio.

[0113] Test case

[0114] In a dry room environment with a dew point of -50℃, the positive electrode active material polyanionic LiFePO4, conductive carbon black SP, and binder polyvinylidene fluoride PVDF were mixed in a mass ratio of 95:2.5:2.5. N-methylpyrrolidone (NMP) was added as a solvent to adjust the mixture to a slurry with a solid content of 63%. The slurry was then coated, rolled, and die-cut to prepare 56*63mm positive electrode sheets for later use.

[0115] The negative electrode active material graphite, conductive carbon black (SP), thickener sodium carboxymethyl cellulose (CMC), binder PAA and styrene-butadiene rubber (SBR) were mixed in a mass ratio of 95:1.0:1.0:1.2:1.8, and deionized water was added as a solvent to adjust to a slurry with a solid content of 52%. The slurry was then coated, rolled, and die-cut to prepare 58*65mm negative electrode sheets for later use.

[0116] The negative electrode, separator, and positive electrode are stacked in 13+12 layers, and the tabs are welded to prepare a soft-pack battery. The battery is then placed in a vacuum dryer and dried for 24 hours to remove moisture.

[0117] In an argon-atmosphere glove box with a water content of <10ppm, non-aqueous organic solvents EC and EMC were mixed at a mass ratio of 30:53.5. Then, 14% LiPF6 was added to the non-aqueous organic solvent, dissolved, and mixed evenly. Next, 2.5% of the additives prepared in Examples 10-19 and Comparative Examples 1-11 were added, and the mixture was stirred evenly to obtain an electrolyte. The electrolyte prepared above was injected into the above-mentioned soft-pack battery cell, and after vacuum sealing, standing, hot pressing formation, capacity testing, and secondary sealing, a lithium-ion battery was obtained.

[0118] The lithium-ion battery was tested using the following method: After electrolyte injection, the battery was immersed at 45°C for 24 hours, then allowed to stand for formation at a low rate of 0.05C. After charging for 3 hours, the rate was increased to 0.2C to reach the upper limit voltage of 3.65V. After a second sealing and venting, an EIS test was performed. The battery was then divided into three capacity tests at 0.5C, and the first discharge capacity was recorded to calculate the first efficiency. The capacity-divided cells were then subjected to rate testing: constant current and constant voltage charging at 0.5C to 3.65V, constant current discharge at 2.0V, constant current and constant voltage charging at 2C to 3.65V, and constant current discharge to 2.0V. The results are shown in Table 1, which presents the performance test results of the lithium-ion battery provided in this application.

[0119] Table 1 Performance test results of the lithium-ion battery provided in this application

[0120] Example 11 90.7 20 92.9 Example 12 91.1 18.7 93 Example 13 92.2 17 94.8 Example 14 90.2 20.1 93.2 Example 15 90.8 18.5 93.9 Example 16 91.0 18.9 94.2 Example 17 92.1 17.2 93.6 Example 18 91.9 17.9 93.3 Example 19 91.0 20.8 92.7 Comparative Example 1 88.4 36.2 89 Comparative Example 2 88 35.9 88.6 Comparative Example 3 88.3 37 88.7 Comparative Example 4 89.1 35.2 87.2 Comparative Example 5 86.5 40.3 86.5 Comparative Example 6 88.9 38.3 87.9 Comparative Example 7 89.3 37.6 89.5 Comparative Example 8 89.0 35.7 89.4 Comparative Example 9 88.1 38.2 87.6 Comparative Example 10 84.2 40.7 80.5 Comparative Example 11 82.7 47.1 79.3

[0121] The comparison of Examples 11-19 showed that the first-effect, membrane impedance, and rate capacity retention of different target products generally exhibited a positive correlation. The effect was related to the energy level window caused by the physicochemical structure-activity relationship of the substituent groups and the solvation structure. The test revealed that the product containing the target product R was relatively optimal. C-3 Secondly, R C-7 R C-8 The number of trimethylsilyl groups may play a more significant role.

[0122] A comparison of Examples 1-11 revealed certain differences between the different chlorotrimethylsilyl derivatives and the target products of Examples 11-19. The relatively optimal product was R. C-7 Secondly, R C-4 R C-8 For comparative examples 10 and 11, which contain only p-tert-butylcalix[4] aromatics, all three showed a certain degree of improvement, indicating that p-tert-butylcalix[4] aromatics have certain advantages.

[0123] The first-effect and membrane impedance R of Examples 11-19 and Comparative Examples 1-11 were compared. SEI The capacity retention of 2C / 0.5C can be seen from the following: Modifying the matrix of trimethylsilicon derivatives to introduce supramolecular p-tert-butylcalix[4] structure can effectively reduce the loss of active lithium during the formation process, effectively stabilize the dynamic balance of SEI / CEI, achieve lower membrane impedance, and fundamentally improve the compatibility of the cell and improve the rate performance.

[0124] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The compound shown in formula (I): Equation (I); in, R1, R2 and R3 are independently selected from alkyl or at least one substituent-substituted alkyl, alkenyl or at least one substituent-substituted alkenyl, alkynyl or at least one substituent-substituted alkynyl, esteryl or at least one substituent-substituted esteryl, alkylamino or at least one substituent-substituted alkylamino, nitrogen-containing heterocyclic or at least one substituent-substituted nitrogen-containing heterocyclic, alkylaminocarbonyl or at least one substituent-substituted alkylaminocarbonyl or alkylcarbonyl or at least one substituent-substituted alkylcarbonyl; R1, R2 and R3 are not all alkyl groups; The substituents are independently selected from halogens, alkyl, alkenyl, alkynyl, alkylsiloxy, or alkylsilyl. The alkyl group is a saturated straight-chain or branched hydrocarbon group having 1 to 6 carbon atoms; The alkenyl group is an unsaturated straight-chain or branched hydrocarbon group having 2 to 6 carbon atoms and a double bond at any desired position; The alkynyl group is an unsaturated straight-chain or branched hydrocarbon group having 2 to 6 carbon atoms and a triple bond at any desired position; The alkylamino group is a straight-chain or branched alkyl group having 1 to 6 carbon atoms bonded to the main structure by an amino group; The alkylaminocarbonyl group is an alkylamino group bonded to the main structure via a carbonyl group; The alkyl carbonyl group is a straight-chain or branched alkyl group having 1 to 6 carbon atoms bonded to the main structure by a carbonyl group; The ester group is a straight-chain or branched alkyl group having 1 to 6 carbon atoms, which is bonded to the main structure via a carbonyl group and an oxygen atom; The nitrogen-containing heterocycle is a nitrogen-containing heterocyclic group bonded to the main structure via -N-. The nitrogen-containing heterocycle is a 5-membered nitrogen-containing heterocyclic group or a nitrogen-containing six-membered heterocycle containing one to four nitrogen atoms or one to three nitrogen atoms and one sulfur or oxygen atom. The alkylsiloxy group is a straight-chain or branched alkyl group having 1 to 6 carbon atoms, which is bonded to the main structure via a siloxy group; The alkylsilyl group is a straight-chain or branched alkyl group having 1 to 6 carbon atoms, which is bonded to the main structure via a silyl group.

2. The compound according to claim 1, characterized in that, R1, R2, and R3 are independently selected from alkyl, alkynyl, halogen-substituted alkyl, or oxazolidinone groups.

3. A compound, characterized in that, With R C-1 ~ R C-9 The structure described: R C-1 ; R C-2 ; R C-3 ; R C-4 ; R C-5 ; R C-6 ; R C-7 ; R C-8 ; R C-9 。 4. An electrolyte additive, characterized in that, Includes the compound described in any one of claims 1 to 3.

5. The electrolyte additive according to claim 4, characterized in that, It also includes one or more of the following: vinylene carbonate, fluorovinyl carbonate, 1,3-propanesulfonate lactone, vinyl sulfate, diphenyl carbonate, toluene carbonate, acrylate, succinic anhydride, succinic anhydride, and adiponitrile.

6. The electrolyte additive according to claim 5, characterized in that, Including fluoroethylene carbonate and vinylene carbonate; The mass ratio of the compound, vinylene carbonate, and fluorovinyl carbonate is (0.1~3):(0.5~1.5):(0.5~1.5).

7. An electrolyte comprising an electrolyte, a solvent, and an additive as described in any one of claims 4 to 6.

8. The electrolyte according to claim 7, characterized in that, The mass concentration of the electrolyte is 5wt%~20wt%; The amount of the additive added is 0.5wt% to 5wt% of the total amount of electrolyte and solvent.

9. A battery comprising the electrolyte of claim 7 or 8.

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