Electrolyte additive, rechargeable battery electrolyte and rechargeable battery

Abstract

The present application discloses an electrolyte additive, a rechargeable battery electrolyte, and a rechargeable battery, belonging to the technical field of rechargeable batteries. The electrolyte additive of the present application has the chemical structure shown below: #imgabs0##imgabs1# wherein, the same X is O or S; the same Y is S, SO, PR; the same R is -OH, NH2, an aromatic group, a C1-C 24 aliphatic group, a C1-C 24 substituted aliphatic group, a C1-C 24 terminally functionalized aliphatic group, a C1-C 24 terminally functionalized substituted aliphatic group. The electrolyte additive of the present application can form strong electron-withdrawing groups such as acyl groups, thioacyl groups, and heteroacyl groups in the molecular structure, effectively regulate the coordination-dissociation equilibrium of the additive molecules with metal cations in the electrolyte, greatly improve the metal ion transport rate at the positive and negative electrode / electrolyte interfaces of the battery, and significantly improve the rate performance and cycle life of the battery.

Description

Technical Field

[0001] The present application belongs to the technical field of rechargeable batteries, and in particular relates to an electrolyte additive, a rechargeable battery electrolyte and a rechargeable battery. Background Art

[0002] Metal-ion batteries have the advantages of high energy density, high voltage, no memory effect, long cycle life and low self-discharge, and are considered to be the most promising next-generation high-energy batteries. However, dendrites and related side reactions will be generated during the charge and discharge cycle of metal electrodes, which not only reduce the battery rate and cycle life, but also may cause safety problems such as electrode short circuits, greatly limiting commercial applications.

[0003] In order to improve the electrochemical performance of metal ion batteries such as cycle life and rate, SE1 film-forming additives can be used to modify the electrolyte. Among them, the SE1 film-forming additives available at this stage are mainly unsaturated ester compounds, sulfur-containing compounds, lithium salts, inorganic compounds, etc.

[0004] However, when the existing SEl film-forming additives are used alone, it is difficult to simultaneously improve the battery rate and cycle life. It often requires the combined use of several SEl film-forming additives, which is costly and may cause unexpected performance changes in the battery. The actual industrial application effect is not ideal. Summary of the invention

[0005] The present application discloses an electrolyte additive, a rechargeable battery electrolyte and a rechargeable battery, aiming to solve the technical problems that the existing SEl film-forming additive cannot improve the battery rate and cycle life at the same time when used alone, and the industrial application effect is not ideal.

[0006] In order to achieve the above purpose, the technical solution of this application is:

[0007] The first aspect of the present application provides an electrolyte additive. The electrolyte additive of the present application has a chemical structure shown in formula [i] to [ii], or formula [iii] to [iv]:

[0008]

[0009] In [i] to [ii], X is O or S;

[0010] [iii] to [iv], the same Y is S, SO, PR;

[0011] In [i] to [iv], R is -OH, NH 2 , aromatic group, C 1 -C 24 The fatty group, C 1 -C 24 Substituted aliphatic groups, C1 -C 24 The terminal functionalized fatty group, C 1 -C 24 One of the terminal functionalized substituted aliphatic groups.

[0012] In combination with the first aspect, preferably, the C 1 -C 24 The substituted aliphatic group contains C 1 -C 24 Halogenated fatty groups, C 1 -C 24 The heteroatom substituted aliphatic group. 1 -C 24 The halogenated aliphatic group is generally understood to be a halogenated aliphatic group in the main chain and / or the side chain; 1 -C 24 The heteroatom-substituted aliphatic group is generally understood to be an aliphatic group containing heteroatom substitutions in the main chain and / or the side chain.

[0013] In combination with the first aspect, preferably, the C 1 -C 24 The terminal functionalized aliphatic group contains C 1 -C 24 The terminal functionalized halogenated aliphatic group, C 1 -C 24 The terminal functionalized heteroatom replaces the aliphatic group. 1 -C 24 The terminal functionalized halogenated aliphatic group is generally understood to be a terminal connected to a functional group known in the art, and the main chain and / or the side chain contains a halogenated aliphatic group; C 1 -C 24 The terminal functionalized heteroatom-substituted aliphatic group is generally understood to be a terminally connected functional group known in the art, and containing the above-mentioned heteroatom-substituted aliphatic group in the main chain and / or the side chain.

[0014] In combination with the first aspect, preferably, the heteroatom forming the heteroatom substitution contains -O-, -S-, -NH-, -OH, -SH, -NH 2 .

[0015] In combination with the first aspect, preferably, the functional groups forming the terminal functionalization contain -OH, -SH, -NH 2 、-CONH 2 , -COOH, -COO - 、-SO 2 H, -SO 2 - 、-SO 3 H, -SO 3- ,-PO 3 H, -PO 3 - 、-B(OH) 2 、-Si(OH) 3 .

[0016] It should be noted that the “aliphatic group”, “halogenated aliphatic group”, “heteroatom-substituted aliphatic group” and “C 1 -C 24 The "terminal functionalized aliphatic group" is understood according to the general meaning in the art. For example, the aliphatic group can be various alkyl, cycloalkyl, olefin or alkyne groups known in the art, wherein the ring, olefin double bond and alkyne triple bond can be connected to any position in the molecular chain.

[0017] In combination with the first aspect, preferably, the electrolyte additive of the present application has a chemical structure shown in formula A1-A10:

[0018]

[0019]

[0020] Among them, R is the same as OH and NH 2 , OR 1 、NHR 1 NR 1 2 or R 1 One of;

[0021] R 1 The same is H, C 1 -C 24 The hydrocarbon group, C 1 -C 24 The halogenated hydrocarbon group, C 1 -C 24 Heteroalkyl, C 1 -C 24 of halogenated heteroalkyl, C 1 -C 24 The terminal functionalized hydrocarbon group, C 1 -C 24 The terminal functionalized halogenated hydrocarbon group, C 1 -C 24 The terminal functionalized heteroalkyl, C 1 -C 24 One of the terminal functionalized halogenated heteroalkyl groups.

[0022] It should be noted that the hydrocarbon group, halogenated hydrocarbon group, heterohydrocarbon group, halogenated heterohydrocarbon group, terminal functionalized hydrocarbon group, terminal functionalized halogenated hydrocarbon group, terminal functionalized heterohydrocarbon group and terminal functionalized halogenated heterohydrocarbon group are all understood according to the general meaning in the art. Specifically:

[0023] The hydrocarbon group described in the present application preferably contains: phenyl, substituted phenyl, heteroaryl, substituted heteroaryl and other aromatic groups; 1 -C 24 Chain alkyl; C 1 -C 24 A chain olefin group, a cycloalkyl group, or a chain alkyl group connected to a cycloalkyl group; C 1 -C 24 The term "chain" refers to a chain alkynyl group, a diene group, or an alkyl group containing two rings, etc. The term "chain" is generally understood to mean a straight-chain or branched structure according to the conventional meaning in the art.

[0024] The halogenated hydrocarbon group described in the present application preferably contains: 1 -C 24 Chain halogenated alkyl; C 1 -C 24 A chain halogenated olefin group, a halogenated cycloalkyl group or a halogenated chain alkyl group connected to a cycloalkyl group; C 1 -C 24 The term "halogenated" is generally understood to mean a halogenated structure containing F, Cl, Br or I in the main chain and / or the side chain according to the conventional meaning in the art.

[0025] The heteroalkyl group described in the present application preferably contains: C 1 -C 24 The main chain and / or side chain of C contains at least one heteroatom-substituted chain saturated aliphatic group as described above; 1 -C 24 The main chain and / or side chain of C contains at least one heteroatom-substituted chain olefin group, cycloalkyl group or chain alkyl group connected with cycloalkyl group as described above; 1 -C 24 The main chain and / or side chain of the alkylene group contains at least one heteroatom-substituted chain alkynyl group, diene group, or alkyl group containing two rings. Among them, heteroatom substitution is generally understood as the main chain and / or side chain containing ether bonds (-O-), tertiary amines Secondary amine (-NH-), thioether bond (-S-), hydroxyl (-OH), amino (-NH 2 ), thiol (-SH), etc.

[0026] The halogenated heteroalkyl group described in the present application preferably contains: 1 -C 24The main chain and / or side chain of C contains at least one of the above-mentioned heteroatoms in the chain halogenated saturated aliphatic group; 1 -C 24 The main chain and / or side chain of C contains at least one heteroatom-substituted chain halogenated olefin group, halogenated cycloalkyl group or halogenated chain alkyl group connected to a cycloalkyl group as described above; 1 -C 24 The main chain and / or side chain of the halogenated alkynyl group, halogenated diene group, or halogenated alkyl group containing two rings substituted with at least one heteroatom as described above. Among them, the halogenated heteroalkyl group is generally understood as a main chain and / or side chain containing an ether bond (-O-), a tertiary amine Secondary amine (-NH-), thioether bond (-S-), hydroxyl (-OH), amino (-NH 2 ), mercapto (-SH), etc., and the main chain and / or side chain contains F, Cl, Br or I halogenated structure.

[0027] The terminal functionalized hydrocarbon group described in the present application preferably contains: 1 -C 24 The main chain and / or side chain terminal groups are functionalized chain alkyl; 1 -C 24 The main chain and / or side chain terminal groups are functionalized with linear heteroolefin groups or heteroalkyl groups containing one ring; 1 -C 24 The main chain and / or side chain terminal groups are functionalized with chain alkynyl groups, diene groups, or alkyl groups containing two rings. The terminal functionalization is generally understood as the main chain and / or side chain terminal groups connected to -CONH 2 , -COOH, -COO - 、-SO 2 H, -SO 2 - 、-SO 3 H, -SO 3 - ,-PO 3 H, -PO 3 - 、-B(OH) 2 、-Si(OH) 3 Functionalized structures such as .

[0028] The terminal functionalized halogenated hydrocarbon group described in the present application preferably contains: 1 -C 24 The main chain and / or side chain terminal groups are functionalized with chain halogenated alkyl; 1 -C 24 The main chain and / or side chain terminal groups are functionalized with chain heterohalogenated olefin groups or halogenated heteroalkyl groups containing one ring; 1 -C24 The main chain and / or side chain terminal groups are functionalized with chain halogenated alkynyl, halogenated diene or halogenated alkyl containing two rings. Among them, the terminal functionalized halogen is generally understood as the main chain and / or side chain terminal group connected to -CONH 2 , -COOH, -COO - 、-SO 2 H, -SO 2 - 、-SO 3 H, -SO 3 - ,-PO 3 H, -PO 3 - 、-B(OH) 2 、-Si(OH) 3 The main chain and / or side chain contain F, Cl, Br or I halogenated structures.

[0029] The terminal functionalized heteroalkyl group described in the present application preferably contains: C 1 -C 24 The main chain and / or side chain terminal groups are functionalized with chain-like saturated heteroaliphatic groups; 1 -C 24 The main chain and / or side chain terminal groups of the present invention are functionalized with heterocyclic olefin groups or heteroalkyl groups containing one ring; 1 -C 24 The main chain and / or side chain terminal groups are functionalized with chain alkynyl groups, diene groups, or alkyl groups containing two rings. Among them, the terminal functionalization hybridization is generally understood as the main chain and / or side chain terminal groups connected to -CONH according to the conventional meaning in the art. 2 , -COOH, -COO - 、-SO 2 H, -SO 2 - 、-SO 3 H, -SO 3 - ,-PO 3 H, -PO 3 - 、-B(OH) 2 、-Si(OH) 3 The main chain and / or side chain contain ether bond (-O-), tertiary amine Secondary amine (-NH-), thioether bond (-S-), hydroxyl (-OH), amino (-NH 2 ), thiol (-SH), etc.

[0030] The terminal functionalized halogenated heteroalkyl group described in the present application preferably contains:1 -C 24 The main chain and / or side chain terminal functionalized chain halogenated saturated heteroaliphatic group; 1 -C 24 The main chain and / or side chain terminal functionalized chain heterohalogenated olefin group or halogenated heteroalkyl group containing one ring; 1 -C 24 The main chain and / or side chain terminal groups are functionalized with chain heterohalogenated alkynyl groups, heterohalogenated diene groups, or halogenated heteroalkanes containing two rings. Among them, the terminal functionalized halogenated heteroaryl is generally understood as the main chain and / or side chain terminal groups connected to -CONH according to the conventional meaning in the art. 2 , -COOH, -COO - 、-SO 2 H, -SO 2 - 、-SO 3 H, -SO 3 - ,-PO 3 H, -PO 3 - 、-B(OH) 2 、-Si(OH) 3 The main chain and / or side chain contain ether bond (-O-), tertiary amine Secondary amine (-NH-), thioether bond (-S-), hydroxyl (-OH), amino (-NH 2 ), thiol (-SH), etc., and the main chain and / or side chain contains F, Cl, Br or I halogenated structure.

[0031] In combination with the first aspect, preferably, the electrolyte additive of the present application contains the compounds shown in B1-B8:

[0032]

[0033]

[0034] The second aspect of the present application provides a rechargeable battery electrolyte. The rechargeable battery electrolyte of the present application contains the electrolyte additive described in the first aspect, and the rechargeable battery electrolyte.

[0035] In combination with the second aspect, preferably, the rechargeable battery electrolyte is one of an ester electrolyte, an ether electrolyte, a nitrile electrolyte, a sulfone electrolyte, an aqueous electrolyte, a mixed electrolyte, and an ionic liquid electrolyte.

[0036] In combination with the second aspect, preferably, the mass volume ratio of the electrolyte additive to the rechargeable battery electrolyte is 0.01-100g:1L.

[0037] The third aspect of the present application provides a rechargeable battery, which comprises two electrode sheets and a separator and an electrolyte separated between the two electrode sheets, wherein the electrolyte comprises the rechargeable battery electrolyte described in the second aspect.

[0038] In combination with the third aspect, preferably, the rechargeable battery of the present application is any one of a metal lithium / lithium ion battery, a metal sodium / sodium ion battery, a metal potassium / potassium ion battery, a metal magnesium / magnesium ion battery, a metal aluminum / aluminum ion battery, a metal zinc / zinc ion battery, and an iron battery.

[0039] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application include at least:

[0040] The electrolyte additive provided in the first aspect of the present application uses cyclohexanehexaimide or cyclopentapentaimide as the structural mother core, and the structural mother core is substituted with -OH, NH 2 , aromatic group, C 1 -C 24 The fatty group, C 1 -C 24 Substituted aliphatic groups, C 1 -C 24 The terminal functionalized fatty group, C 1 -C 24 The terminal functionalized fatty groups are substituted. On the one hand, the acyl, thioacyl, heteroacyl and the like in the molecular structure core are strong electron-withdrawing groups, which can effectively regulate the coordination-dissociation balance of the additive molecules to the metal cations in the electrolyte, thereby greatly improving the metal ion transmission rate at the positive and negative electrode / electrolyte interface of the battery, and realizing the improvement of the battery rate performance; on the other hand, the good coordination ability of the abundant N, O, S, P and other heteroatoms in the molecules can be utilized to make the additive effectively adsorbed on the positive and negative electrode surfaces and participate in the formation of stable CEI and SEI interface films, which has the advantages of Effectively block the side reactions between the positive and negative electrode active materials and the electrolyte molecules; thirdly, modifying different substituents can effectively regulate the uniformity of the accumulation of additive molecules at the interface of the positive and negative electrodes of the battery, as well as the efficiency and stability of film formation, thereby regulating the uniformity of the distribution of metal ions at the interface, and effectively inhibiting the microstructural phase change of the positive electrode active material and the growth of the negative electrode metal dendrites; fourthly, based on the above three advantages, the additive of the present application has an accurate structure, simple preparation, and good solubility. A single application can simultaneously improve the rate performance and cycle life of the battery, and has good prospects for industrial application.

[0041] The rechargeable battery electrolyte provided in the second aspect of the present application contains the electrolyte additive, and the electrolyte additive has the advantages of simultaneously improving the rate performance and cycle life of the battery and having good industrial application prospects. Therefore, when the rechargeable battery electrolyte of the present application contains the electrolyte additive, it can not only effectively improve the rate performance and cycle life of the battery, but also effectively promote the low-cost commercial application of the electrolyte additive.

[0042] The rechargeable battery provided in the third aspect of the present application can effectively improve the rate performance and cycle life of the battery by using the rechargeable battery electrolyte. Therefore, when the rechargeable battery contains the rechargeable battery electrolyte, the rate performance and cycle life of the battery can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1-1 Cycling curves of Li / Li batteries containing ether-based LiTFSI electrolyte AEC1 and modified electrolyte EC1 provided in the embodiments of the present application;

[0045] Figure 1-2 Performance test diagram of lithium iron phosphate / Li battery containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC1 provided in the embodiments of the present application;

[0046] Figure 2-1 Cycling curves of Li / Li batteries containing nitrile-containing LiTFSI electrolyte AEC2 and modified electrolyte EC2 provided in the examples of the present application;

[0047] Figure 2-2 Performance test diagram of ternary lithium (NCM523) / Li battery containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC2 provided in the examples of the present application;

[0048] Figure 3-1 The ester-containing LiPF 6 Cycling curves of Li / Li batteries with electrolyte AEC3 and modified electrolyte EC3;

[0049] Figure 3-2 The embodiment of the present application provides ester LiPF 6Performance test diagram of electrolyte AEC3 and lithium iron phosphate / Li battery containing modified electrolyte EC3;

[0050] Figure 4-1 Cycling curves of Li / Li batteries containing ether-based LiTFSI electrolyte AEC1 and modified electrolyte EC4 provided in the examples of the present application;

[0051] Figure 4-2 Performance test diagram of lithium iron phosphate / Li battery containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC4 provided in the embodiments of the present application;

[0052] Figure 5-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC5 provided in the examples of the present application;

[0053] Figure 5-2 Performance test diagram of lithium cobalt oxide / Li battery containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC5 provided in the examples of the present application;

[0054] Figure 6-1 The ester-containing LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC3 and modified electrolyte EC6;

[0055] Figure 6-2 The ester-containing LiPF 6 Performance test diagram of lithium nickel manganese oxide / Li battery containing electrolyte AEC3 and modified electrolyte EC6;

[0056] Figure 7-1 Cycling curves of Li / Li batteries containing ether-based LiTFSI electrolyte AEC1 and modified electrolyte EC7 provided in the examples of the present application;

[0057] Figure 7-2 Performance test diagram of lithium iron phosphate / Li battery containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC7 provided in the embodiments of the present application;

[0058] Figure 8-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC8 provided in the examples of the present application;

[0059] Figure 8-2 Performance test diagram of lithium nickel manganese oxide / Li battery containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC8 provided in the embodiments of the present application. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] It should be noted that all raw materials, reagents and compounds in the examples of this application are purchased on the market or synthesized according to methods known in the art, and this application does not impose any special restrictions on this. At the same time, the parameter configuration of the same battery mold described in the examples of this application is the same, for example: Li / Li button-type symmetrical mold full battery (lithium foil diameter is 1 cm); lithium manganese oxide / Li mold full battery (positive electrode plate diameter is 1 cm, nickel manganese oxide lithium manganese oxide / Li mold full battery (positive electrode plate diameter is 1 cm, nickel manganese oxide surface loading is 1.2 mg·cm -2 , lithium foil diameter is 1 cm); lithium iron phosphate / Li mold full battery (positive electrode sheet diameter is 1 cm, lithium iron phosphate surface loading is 1.2 mg cm -2 , lithium foil diameter is 1 cm); ternary lithium (NCM811) / Li mold full battery (positive electrode sheet diameter is 1 cm, NCM811 surface loading is 1.2 mg cm -2 , lithium foil diameter is 1 cm); LiCoO2 / Li mold full battery (positive electrode sheet diameter is 1 cm, LiCoO2 surface loading is 1.2 mg cm -2 , the diameter of lithium foil is 1 cm).

[0062] Example 1

[0063] This embodiment provides a method for preparing a modified electrolyte EC1 containing hexabutoxycarbonylcyclohexaneheximide, comprising the following steps:

[0064] 27 g of hexabutoxycarbonylcyclohexaneheximide was dissolved in 1 L of ether LiTFSI electrolyte AEC1 to form modified electrolyte EC1. The ether LiTFSI electrolyte AEC1 contained 1 mmol / L of LiPF 6 , the solvent is 1,3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1; the chemical structure of hexabutoxycarbonylcyclohexaneheximide is shown in B1:

[0065] B 1:

[0066] In order to study the effect of adding hexabutyloxycarbonylcyclohexaneheximide on the performance of ether-based LiTFSI electrolyte, the following two experiments were conducted in this example:

[0067] Experiment 1-1

[0068] Take two identical Li / Li button-type symmetrical cells and load 0.1 mL of ether LiTFSI electrolyte AEC1 and 0.1 mL of modified electrolyte EC1 into the two mold full cells respectively. -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 1-1 As shown. Among them, Figure 1-1 Cycling curves of Li / Li batteries containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC1.

[0069] according to Figure 1-1 It can be seen that compared with the Li / Li battery containing the ether LiTFSI electrolyte AEC1, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC1 is reduced from 0.35V to 0.15V, and the stable cycle time is increased from 45h to more than 250h, indicating that the addition of hexabutoxycarbonylcyclohexaneheximide to the ether LiTFSI electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0070] Experiment 1-2

[0071] Take two identical lithium iron phosphate / Li mold full cells, and respectively load 0.1mL of ether LiTFSI electrolyte AEC1 and 0.1mL of modified electrolyte EC1 into the two mold full cells, and then test the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries at a current density of 10C. The results are as follows: Figure 1-2 As shown. Among them, Figure 1-2 Performance test diagram of lithium iron phosphate / Li battery containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC1.

[0072] according to Figure 1-2 It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of the lithium iron phosphate / Li battery containing the modified electrolyte EC1 are significantly improved compared with the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC1. Among them, at a current density of 10C, the lithium iron phosphate / Li battery containing the modified electrolyte EC1 has a stable cycle of more than 500 cycles, and no capacity decay occurs during the cycle, while the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC1 has a battery capacity decay of less than 50% of the initial capacity after 500 cycles, indicating that the addition of a single hexabutyloxycarbonylcyclohexaneheximide to the ether LiTFSI electrolyte can significantly improve the battery's cycle life and rate performance.

[0073] Example 2

[0074] This embodiment provides a method for preparing a modified electrolyte EC2 containing hexadimethoxyphosphonylcyclohexaneheximide, comprising the following steps:

[0075] 3.2 g of hexamethoxyphosphonylcyclohexane hexamethyleneimine was dissolved in 1 L of nitrile LiTFSI electrolyte AEC2 to form modified electrolyte EC2. The nitrile LiTFSI electrolyte AEC2 contained 1 mmol / L of LiTFSI, and the solvent was acetonitrile and succinonitrile in a volume ratio of 2:1; the chemical structure of hexamethoxyphosphonylcyclohexane hexamethyleneimine is shown in B2:

[0076] B2:

[0077] In order to study the effect of adding hexadimethoxyphosphonylcyclohexaneheximide on the performance of nitrile LiTFSI electrolyte, the following two experiments were conducted in this example:

[0078] Experiment 2-1

[0079] Take two identical Li / Li button-type symmetrical cells and load 0.1 mL of nitrile LiTFSI electrolyte AEC2 and 0.1 mL of modified electrolyte EC2 into the two mold full cells respectively. -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 2-1 As shown. Among them, Figure 2-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC2.

[0080] according to Figure 2-1 It can be seen that compared with the Li / Li battery containing the nitrile LiTFSI electrolyte AEC2, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC2 is reduced from 0.35V to 0.2V, and the stable cycle time is increased from 50h to more than 300h, indicating that the addition of hexadimethoxyphosphonylcyclohexaneheximide to the nitrile LiTFSI electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0081] Experiment 2-2

[0082] Take two identical ternary lithium (NCM523) / Li mold full cells, and respectively load 0.1mL of nitrile LiTFSI electrolyte AEC2 and 0.1mL of modified electrolyte EC2 into the two mold full cells, and then test the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries at a current density of 5C. The results are as follows: Figure 2-2 As shown. Among them, Figure 2-2Performance test diagram of ternary lithium (NCM523) / Li battery containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC2.

[0083] according to Figure 2-2 It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of the ternary lithium (NCM523) / Li battery containing the modified electrolyte EC2 are significantly improved compared with the ternary lithium (NCM523) / Li battery containing the nitrile LiTFSI electrolyte AEC2. Among them, at a current density of 5C, the ternary lithium (NCM523) / Li battery containing the modified electrolyte EC2 has a stable cycle of more than 800 cycles, and no capacity decay occurs during the cycle, while the capacity of the ternary lithium (NCM523) / Li battery containing the nitrile LiTFSI electrolyte AEC2 rapidly decays after 300 cycles, indicating that the addition of a single hexamethoxyphosphonylcyclohexaneheximide to the nitrile LiTFSI electrolyte can significantly improve the battery's cycle life and rate performance.

[0084] Example 3

[0085] This embodiment provides a method for preparing a modified electrolyte EC3 containing hexa-4-butene-1-acylcyclohexaneheximide, comprising the following steps:

[0086] Dissolve 0.26 g of hexa-4-butene-1-acylcyclohexane hexamethyleneimine in 1 L of ester LiPF 6 The modified electrolyte EC3 is formed in the electrolyte AEC3. Among them, the ester LiPF 6 The electrolyte AEC3 contains 1 mmol / L of LiTF SI, and the solvent is dimethyl carbonate, ethyl methyl carbonate and ethylene carbonate in a volume ratio of 1:1:1; the chemical structure of hexa-4-butene-1-acylcyclohexaneheximide is shown in B3:

[0087] B3:

[0088] In order to study the addition of hexa-4-butene-1-ylcyclohexaneheximide to ester LiPF 6 The influence of electrolyte performance, this embodiment carries out the following two experiments:

[0089] Experiment 3-1

[0090] Take two identical Li / Li button-type symmetrical cells and load 0.1 mL of ester LiPF into each of the two mold full cells. 6 After adding electrolyte AEC3 and 0.1 mL of modified electrolyte EC2, at 1 mAh cm -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 3-1As shown. Among them, Figure 3-1 Containing ester LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC3 and modified electrolyte EC3.

[0091] according to Figure 3-1 It can be seen that the ester-containing LiPF 6 Compared with the Li / Li battery with electrolyte AEC3, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC3 is reduced from 0.35V to 0.1V, and the stable cycle time is increased from 50h to more than 250h, indicating that the ester LiPF 6 Adding hexa(4-butene-1-yl)cyclohexaneheximide into the electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of Li / Li batteries.

[0092] Experiment 3-2

[0093] Take two identical lithium iron phosphate / Li mold full cells and add 0.1 mL of ester LiPF into each mold full cell. 6 After adding 0.1mL of electrolyte AEC3 and modified electrolyte EC3, the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries were tested at a current density of 10C. The results are Figure 3-2 As shown. Among them, Figure 3-2 Containing ester LiPF 6 Performance test diagram of electrolyte AEC3 and lithium iron phosphate / Li battery containing modified electrolyte EC3.

[0094] according to Figure 3-2 It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of lithium iron phosphate / Li batteries containing modified electrolyte EC3 are better than those containing ester LiPF 6 The lithium iron phosphate / Li battery with electrolyte AEC3 has been significantly improved. Among them, at a current density of 10C, the capacity of the lithium iron phosphate / Li battery containing modified electrolyte EC1 increased by nearly 10mAh / g, and the stable cycle exceeded 500 cycles, and no capacity decay occurred during the cycle, while the lithium iron phosphate / Li battery containing ester LiPF 6 After 500 cycles of the lithium iron phosphate / Li battery with electrolyte AEC3, the capacity decayed to less than 50% of the initial capacity, indicating that the ester LiPF 6 Adding a single hexa(4-butene-1-acylcyclohexaneheximide) into the electrolyte can significantly improve the cycle life and rate performance of the battery.

[0095] Example 4

[0096] This embodiment provides a method for preparing a modified electrolyte EC4 containing hexaepoxybutane-2-sulfonylcyclohexaneheximide, comprising the following steps:

[0097] 38 g of hexacyclic 2-sulfonyl cyclohexane hexamethyleneimine was dissolved in 1 L of ether LiTFSI electrolyte AEC1 to form modified electrolyte EC4. The ether LiTFSI electrolyte AEC1 contained 1 mmol / L of LiPF 6 , the solvent is 1,3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1; the chemical structure of hexacyclobutane-2-sulfonylcyclohexaneheximide is shown in B4:

[0098] B4:

[0099] In order to study the effect of adding hexacyclic butylene-2-sulfonylcyclohexaneheximide on the performance of ether-based LiTFSI electrolyte, the following two experiments were conducted in this example:

[0100] Experiment 4-1

[0101] Take two identical Li / Li button-type symmetrical cells and load 0.1 mL of ether-based LiTFSI electrolyte AEC1 and 0.1 mL of modified electrolyte EC4 into the two mold full cells respectively. -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 4-1 As shown. Among them, Figure 4-1 Cycling curves of Li / Li batteries containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC4.

[0102] according to Figure 1-1 It can be seen that compared with the Li / Li battery containing the ether LiTFSI electrolyte AEC1, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC4 is reduced from 0.3V to 0.1V, and the stable cycle time is increased from 45h to more than 300h, indicating that the addition of hexacyclic 2-sulfonylcyclohexaneheximide to the ether LiTFSI electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0103] Experiment 4-2

[0104] Take two identical lithium iron phosphate / Li mold full cells, and respectively load 0.1mL of ether LiTFSI electrolyte AEC1 and 0.1mL of modified electrolyte EC4 into the two mold full cells, and then test the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries at a current density of 10C. The results are as follows: Figure 4-2 As shown. Among them, Figure 4-2 Performance test diagram of lithium iron phosphate / Li battery containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC4.

[0105] according to Figure 4-2 It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of the lithium iron phosphate / Li battery containing the modified electrolyte EC4 are significantly improved compared with the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC1. Among them, at a current density of 10C, the capacity of the lithium iron phosphate / Li battery containing the modified electrolyte EC4 is increased by nearly 30mAh / g, and the stable cycle exceeds 1000 cycles, and the coulombic efficiency remains close to 100%, while the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC1 can only be stable for 600 cycles, and there is obvious overcharge and overdischarge phenomenon, and the capacity is significantly attenuated after 200 cycles, indicating that the addition of a single hexacyclic 2-sulfonyl cyclohexane hexamethyleneimine to the ether LiTFSI electrolyte can significantly improve the battery's cycle life and rate performance.

[0106] Example 5

[0107] This embodiment provides a method for preparing a modified electrolyte EC5 containing hexasulfinic acid-2-trifluoromethoxyethyl cyclohexaneheximide, comprising the following steps:

[0108] 96 g of hexasulfinic acid-2-trifluoromethoxyethyl cyclohexane hexamethyleneimine was dissolved in 1 L of nitrile LiTFSI electrolyte AEC2 to obtain modified electrolyte EC5. The nitrile LiTFSI electrolyte AEC2 contained 1 mmol / L LiTFSI, and the solvent was acetonitrile and succinonitrile in a volume ratio of 2:1; the chemical structure of hexasulfinic acid-2-trifluoromethoxyethyl cyclohexane hexamethyleneimine is shown in B5:

[0109] B5:

[0110] In order to study the effect of adding hexasulfinic acid-2-trifluoromethoxyethyl cyclohexane hexamethyleneimine on the performance of nitrile LiTFSI electrolyte, the following two experiments were conducted in this example:

[0111] Experiment 5-1

[0112] Take two identical Li / Li button-type symmetrical cells and load 0.1 mL of nitrile LiTFSI electrolyte AEC2 and 0.1 mL of modified electrolyte EC5 into the two mold full cells respectively. -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 5-1 As shown. Among them, Figure 5-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC5.

[0113] according to Figure 5-1 It can be seen that compared with the Li / Li battery containing the nitrile LiTFSI electrolyte AEC2, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC5 is reduced from 0.7V to 0.3V, and the stable cycle time is increased from 80h to more than 265h, indicating that the addition of hexasulfinic acid-2-trifluoromethoxyethyl cyclohexaneheximide to the nitrile LiTFSI electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0114] Experiment 5-2

[0115] Take two identical lithium cobalt oxide / Li mold full cells, and respectively load 0.1mL of nitrile LiTFSI electrolyte AEC2 and 0.1mL of modified electrolyte EC5 into the two mold full cells, and then test the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries at a current density of 5C. The results are as follows: Figure 5-2 As shown. Among them, Figure 5-2 Performance test diagram of lithium cobalt oxide / Li battery containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC5.

[0116] according to Figure 5-2 It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of the lithium cobalt oxide / Li battery containing the modified electrolyte EC5 are significantly improved compared with the lithium cobalt oxide / Li battery containing the nitrile LiTFSI electrolyte AEC2. Among them, at a current density of 5C, the capacity of the lithium cobalt oxide / Li battery containing the modified electrolyte EC2 is increased by nearly 50mAh / g, and the stable cycle exceeds 700 cycles, while the capacity of the lithium cobalt oxide / Li battery containing the nitrile LiTFSI electrolyte AEC2 rapidly decays after 200 cycles, and the capacity is almost zero after 600 cycles, indicating that the addition of a single hexasulfonic acid-2-trifluoromethoxyethyl cyclohexane hexaimide to the nitrile LiTFSI electrolyte can significantly improve the battery's cycle life and rate performance.

[0117] Example 6

[0118] This embodiment provides a method for preparing a modified electrolyte EC6 containing penta-4-butylbenzenesulfinylcyclopentanepentaimide, comprising the following steps:

[0119] Dissolve 4.0 g of 4-butylbenzenesulfinylcyclopentanepentaimide in 1 L of ester LiPF 6 The modified electrolyte EC6 is formed in the electrolyte AE C3. Among them, the ester LiPF 6 The electrolyte AEC3 contains 1 mmol / L Li TFSI, and the solvent is dimethyl carbonate, ethyl methyl carbonate and ethylene carbonate in a volume ratio of 1:1:1; the chemical structure of penta-4-butylbenzenesulfinylcyclopentane pentamethyleneimine is shown in B6:

[0120] B6:

[0121] In order to study the addition of 4-butylbenzenesulfinylcyclopentaimide to ester LiPF 6 The influence of electrolyte performance, this embodiment carries out the following two experiments:

[0122] Experiment 6-1

[0123] Take two identical Li / Li button-type symmetrical cells and add 0.1 mL of ester LiPF into each of the two mold full cells. 6 After adding 0.1 mL of the modified electrolyte EC6 and the electrolyte AEC3, the -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 6-1 As shown. Among them, Figure 6-1 Containing ester LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC3 and modified electrolyte EC6.

[0124] according to Figure 6-1 It can be seen that the ester-containing LiPF 6 Compared with the Li / Li battery with electrolyte AEC3, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC6 was reduced from 0.3V to 0.1V, and the stable cycle time was increased from 50h to more than 250h, indicating that the ester LiPF 6 Adding penta-4-butylbenzenesulfinylcyclopentanepentaimide to the electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of Li / Li batteries.

[0125] Experiment 6-2

[0126] Take two identical nickel manganese oxide / Li mold full cells and add 0.1 mL of ester LiPF into each of the two mold full cells. 6 After adding 0.1mL of electrolyte AEC3 and modified electrolyte EC6, the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries were tested at a current density of 2C. The results are Figure 6-2 As shown. Among them, Figure 6-2 Containing ester LiPF 6 Performance test diagram of lithium nickel manganese oxide / Li battery containing electrolyte AEC3 and modified electrolyte EC6.

[0127] according to Figure 6-2 It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of the nickel manganese oxide / Li battery containing the modified electrolyte EC6 are better than those containing the ester LiPF6 The capacity of the LiMnO2 / Li battery containing the modified electrolyte EC6 increased by nearly 30 mAh / g at a current density of 2C, and the stable cycle lasted for more than 1000 cycles without capacity decay during the cycle. At the same time, the coulombic efficiency remained close to 100%, indicating that the ester LiPF 6 Adding a single 4-butylbenzenesulfinylcyclopentanepentaimide into the electrolyte can significantly improve the cycle life and rate performance of the battery.

[0128] Example 7

[0129] This embodiment provides a method for preparing a modified electrolyte EC 7 containing pentatrifluorocyclopropylaminosulfonylcyclopentaimide, comprising the following steps:

[0130] 4.0 g of pentatrifluorocyclopropylamine sulfonylcyclopentaimide was dissolved in 1 L of ether LiTFSI electrolyte AEC1 to form modified electrolyte EC7. The ether LiTFSI electrolyte AEC1 contained 1 mmol / L of LiPF 6 , the solvent is 1,3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1; the chemical structure of pentatrifluorocyclopropylaminosulfonylcyclopentaimide is shown in B7:

[0131] B7:

[0132] In order to study the effect of adding pentatrifluorocyclopropylaminosulfonylcyclopentaimide on the performance of ether-based LiTFSI electrolyte, the following two experiments were conducted in this example:

[0133] Experiment 7-1

[0134] Take two identical Li / Li button-type symmetrical cells and add 0.1 mL of ether LiTFSI electrolyte AEC1 and 0.1 mL of modified electrolyte EC7 into the two mold full cells respectively. -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 7-1 As shown. Among them, Figure 7-1 Cycling curves of Li / Li batteries containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC7.

[0135] according to Figure 7-1It can be seen that compared with the Li / Li battery containing the ether LiTFSI electrolyte AEC1, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC7 is reduced from 0.3V to 0.1V, and the stable cycle time is increased from 50h to more than 275h, indicating that the addition of pentatrifluorocyclopropylaminosulfonylcyclopentanepentaimide to the ether LiTFSI electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0136] Experiment 7-2

[0137] Take two identical lithium iron phosphate / Li mold full cells, and respectively load 0.1mL of ether LiTFSI electrolyte AEC1 and 0.1mL of modified electrolyte EC7 into the two mold full cells, and then test the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries at a current density of 10C. The results are as follows: Figure 7-2 As shown. Among them, Figure 7-2 Performance test diagram of lithium iron phosphate / Li battery containing ether LiTFSI electrolyte AEC1 and modified electrolyte EC7.

[0138] according to Figure 7-2 It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of the lithium iron phosphate / Li battery containing the modified electrolyte EC7 are significantly improved compared with the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC1. Among them, at a current density of 10C, the capacity of the lithium iron phosphate / Li battery containing the modified electrolyte EC7 is increased by about 30mAh / g, and the stable cycle exceeds 500 cycles, while the capacity of the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC1 decays after 200 cycles, indicating that the addition of a single pentatrifluorocyclopropylaminosulfonylcyclopentane pentamethyleneimine to the ether LiTFSI electrolyte can significantly improve the battery's cycle life and rate performance.

[0139] Example 8

[0140] This embodiment provides a method for preparing a modified electrolyte EC8 containing pentathio 2-fluorocyclobutyrylcyclopentaimide, comprising the following steps:

[0141] 2.8 g of 2-fluorocyclobutyryl cyclopentane pentasulfide was dissolved in 1 L of nitrile LiTFSI electrolyte AEC2 to form modified electrolyte EC8. The nitrile LiTFSI electrolyte AEC2 contained 1 mmol / L LiTFSI, and the solvent was acetonitrile and succinonitrile in a volume ratio of 2:1; the chemical structure of 2-fluorocyclobutyryl cyclopentane pentasulfide was shown in B8:

[0142] B8:

[0143] In order to study the effect of adding 2-fluorocyclobutyryl cyclopentadienyl imine pentathioate on the performance of nitrile LiTFSI electrolyte, the following two experiments were conducted in this example:

[0144] Experiment 8-1

[0145] Take two identical Li / Li button-type symmetrical cells and load 0.1 mL of nitrile LiTFSI electrolyte AEC2 and 0.1 mL of modified electrolyte EC8 into the two mold full cells respectively. -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 8-1 As shown. Among them, Figure 8-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC8.

[0146] according to Figure 8-1 It can be seen that compared with the Li / Li battery containing the nitrile LiTFSI electrolyte AEC2, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC8 is significantly reduced, and the stable cycle time is increased from 50h to more than 300h, indicating that the addition of pentathio 2-fluorocyclobutyrylcyclopentaimide to the nitrile LiTFSI electrolyte can effectively reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0147] Experiment 8-2

[0148] Take two identical lithium nickel manganese oxide / Li mold full cells, and respectively load 0.1mL of nitrile LiTFSI electrolyte AEC2 and 0.1mL of modified electrolyte EC8 into the two mold full cells, and then test the coulombic efficiency, cycle stability, capacity and retention rate of the two batteries at a current density of 2C. The results are as follows: Figure 8-2 As shown. Among them, Figure 8-2 Performance test diagram of lithium nickel manganese oxide / Li battery containing nitrile LiTFSI electrolyte AEC2 and modified electrolyte EC8.

[0149] according to Figure 8-2It can be seen that the coulombic efficiency, cycle stability, capacity and retention rate of the nickel manganese oxide lithium / Li battery containing the modified electrolyte EC8 are significantly improved compared with the nickel manganese oxide lithium / Li battery containing the nitrile LiTFSI electrolyte AEC2. Among them, at a current density of 2C, the capacity of the nickel manganese oxide lithium / Li battery containing the modified electrolyte EC8 is increased by nearly 30mAh / g, and the stable cycle exceeds 1000 cycles, and the capacity remains above 90mAh / g after 1000 cycles, while the capacity of the nickel manganese oxide lithium / Li battery containing the nitrile LiTFSI electrolyte AEC2 is less than 45mAh / g after 1000 cycles, indicating that the addition of a single pentathio 2-fluorocyclobutyryl cyclopentane pentamethyleneimine to the nitrile LiTFSI electrolyte can significantly improve the battery's cycle life and rate performance.

[0150] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0151] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions recorded in the aforementioned embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. An electrolyte additive, It is characterized in that Contains the compounds shown in B1-B8:

2. A rechargeable battery electrolyte, It is characterized in that Contains the electrolyte additive as claimed in claim 1, and the main electrolyte of the rechargeable battery.

3. The rechargeable battery electrolyte according to claim 2, It is characterized in that The rechargeable battery electrolyte is selected from one of ester electrolyte, ether electrolyte, nitrile electrolyte, sulfone electrolyte, aqueous electrolyte, mixed electrolyte, and ionic liquid electrolyte.

4. The rechargeable battery electrolyte according to claim 2 or 3, It is characterized in that The mass volume ratio of the electrolyte additive to the rechargeable battery electrolyte is 0.01-100g:1L.

5. A rechargeable battery comprising two electrode sheets and a separator and an electrolyte between the two electrode sheets, It is characterized in that The electrolyte contains the rechargeable battery electrolyte according to any one of claims 2-4.

6. The rechargeable battery according to claim 5, It is characterized in that It is any one of metal lithium / lithium ion battery, metal sodium / sodium ion battery, metal potassium / potassium ion battery, metal magnesium / magnesium ion battery, metal aluminum / aluminum ion battery, metal zinc / zinc ion battery, and iron battery.

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