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# wherein, R is identically one of -H, a C1-C 24 aliphatic group, a C1-C 24 substituted aliphatic group, a C1-C 24 terminally functionalized aliphatic group. The electrolyte additive of the present application can effectively inhibit the side reactions between the rechargeable battery electrolyte and the positive and negative electrodes of the battery, thereby improving the kinetic performance of the rechargeable battery and reducing the consumption of the electrolyte, significantly increasing the cycle life of the rechargeable battery, and can be used in various organic electrolytes.

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 attracted much attention due to their advantages such as high voltage, high capacity, no memory effect, long cycle life and low self-discharge. However, during the charge and discharge cycle of metal-ion batteries, dendrites and their related side reactions generally occur, which greatly damages the cycle life of metal-ion batteries.

[0003] In order to solve the above problems, the related art discloses that the electrolyte can be modified by using film-forming additives, specifically, adding film-forming additives to the electrolyte to optimize the chemical properties and surface structure of the SEI film, so that the SEI film can effectively improve the cycle life of the battery. At present, the common film-forming additives that can be used to optimize the SEI film in the related art are: 1) unsaturated ester additives such as VC, FEC, VEC, CC, AEC, VA, etc.; 2) sulfur-containing additives such as sultones and sulfates; 3) lithium salt additives such as lithium bis(oxalatoborate); 4) CO 2 、SO 2 、Na 2 CO 3 and other inorganic compound additives; 5) other additives such as silanes and acid anhydrides.

[0004] However, the above-mentioned film-forming additives are prone to the following problems in practical applications: 1) It is difficult for a single ester additive to meet multiple performance requirements, and it is often necessary to use several in combination, which is costly; 2) Sulfur-containing additives have multiple sulfur valence states, resulting in different decomposition products and decomposition pathways, which may cause unexpected changes in battery performance, and it is often necessary to use several in combination; 3) Lithium salt additives and inorganic compound additives generally have poor solubility, and require the selection of appropriate solvents to match, which increases costs and may cause unexpected changes in battery performance; 4) Other additives are not conducive to industrial application due to complex preparation and high cost. 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 single film-forming additive has unsatisfactory industrial application effect, high cost and may cause unexpected changes in battery performance.

[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, wherein the electrolyte additive has a chemical structure shown in formula [i] or formula [ii]:

[0008]

[0009] Among them, R is -H, C 1 -C 24 The fatty group, C 1 -C 24 Substituted aliphatic groups, C 1 -C 24 The terminal functionalized aliphatic group, C 1 -C 24 One of the terminal functionalized substituted aliphatic groups.

[0010] 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 fatty group. It should be understood in the art that the C 1 -C 24 The halogenated aliphatic group is generally interpreted as a halogenated aliphatic group in the main chain and / or the side chain; 1 -C 24 The heteroatom-substituted aliphatic group is generally interpreted as an aliphatic group containing heteroatom substitutions in the main chain and / or the side chain.

[0011] In combination with the first aspect, preferably, the heteroatom forming the heteroatom substitution contains -O-, -S-, -NH-, -OH, -SH, -NH 2 .

[0012] 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. It should be understood in the art that C 1 -C 24 The terminal functionalized halogenated aliphatic group is generally interpreted as a functional group known in the art connected to the terminal, and a halogenated aliphatic group is contained in the main chain and / or the side chain; C 1 -C 24 The terminal functionalized heteroatom substituted aliphatic group is generally interpreted as a functional group known in the art connected to the terminal, and containing the above-mentioned heteroatom substituted aliphatic group in the main chain and / or the side chain.

[0013] In combination with the first aspect, preferably, the functional groups forming the terminal functionalization contain -OH, -SH, -NH2 、-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 .

[0014] 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 is 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.

[0015] In combination with the first aspect, preferably, according to some substitutions of the above R groups, the electrolyte additive of the present application has a chemical structure shown in any one of formulas [i-A1] to [i-A24], or has a chemical structure shown in any one of formulas [ii-A1] to [ii-A24]:

[0016] [i-A1]:

[0017] Among them, 0≤n<24;

[0018] [i-A2]:

[0019] Wherein, X=F, CI, Br or I; 0≤n<24; m≤2n+1;

[0020] [i-A3]: Wherein, Y=O, N, NH or S; 0≤n<24; o≤n;

[0021] [i-A4]: Wherein, X=F, CI, Br or I; Y=O, N, NH or S; 0≤n<24; m≤2n+1; o≤n; [i-A5]: Among them, 2≤n<24;

[0022] [i-A6]: Wherein, X=F, CI, Br or I; 2≤n<24; m≤2n-1;

[0023] [i-A7]: Wherein, Y=O, N, NH or S; 2≤n<24; o≤n;

[0024] [i-A8]:

[0025] Wherein, X=F, CI, Br or I; Y=O, N, NH or S; 2≤n<24; m≤2n-1; o≤n; [i-A9]:

[0026] Among them, 2≤n<24;

[0027] [i-A10]:

[0028] Wherein, X=F, CI, Br or I; 2≤n<24; m≤2n-3;

[0029] [i-A11]:

[0030] Wherein, Y=O, N, NH or S; 2≤n<24; o≤n; m≤2n-3;

[0031] [i-A12]:

[0032] Wherein, X=F, CI, Br or I; Y=O, N, NH or S; 2≤n<24; m≤2n-3; o≤n;

[0033] [i-A13]:

[0034] Among them, R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 0≤n<24;

[0035] [i-A14]:

[0036] Wherein, X=F, CI, Br or I; R 1 =Aryl, CONH2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 0≤n<24; m≤2n;

[0037] [i-A15]:

[0038] Wherein, Y=O, N, NH or S;

[0039] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0040] B(OH) 2 or Si(OH) 3 ; 0≤n<24; o≤n;

[0041] [i-A16]:

[0042] Wherein, X=F, CI, Br or I; Y=O, N, NH or S;

[0043] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0044] B(OH) 2 or Si(OH) 3; 0≤n<24; o≤n; m≤2n;

[0045] [i-A17]:

[0046] Among them, R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 2≤n<24;

[0047] [i-A18]:

[0048] Wherein, X=F, CI, Br or I; R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 2≤n<24; m≤2n-2;

[0049] [i-A19]:

[0050] Wherein, Y=O, N, NH or S;

[0051] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0052] B(OH) 2 or Si(OH) 3 ; 2 ≤ n < 24; o ≤ n;

[0053] [i-A20]:

[0054] Wherein, X = F, Cl, Br or I; Y = O, N, NH or S;

[0055] R 1 = aryl, CONH 2 , COOH, COO - , SO 2 H, SO 2 - , SO 3 H, SO 3 - , PO 3 H, PO 3 - ,

[0056] B(OH) 2 or Si(OH) 3 ; 2 ≤ n < 24; o ≤ n; m ≤ 2n - 2;

[0057] [i-A21]:

[0058] Wherein, R 1 = aryl, CONH 2 , COOH, COO - , SO 2 H, SO 2 - , SO 3 H, SO 3 - , PO 3 H, PO 3 - , B(OH) 2 or Si(OH) 3 ; 2 ≤ n < 24;

[0059] [i-A22]:

[0060] Wherein, X = F, Cl, Br or I; R 1 = aryl, CONH 2 , COOH, COO - , SO 2 H, SO 2 - , SO 3 H, SO3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 2≤n<24; m≤2n-4;

[0061] [i-A23]:

[0062] Wherein, Y=O, N, NH or S; R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 2≤n<24; o≤n;

[0063] [i-A24]:

[0064] Wherein, X=F, CI, Br or I; Y=O, N, NH or S;

[0065] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0066] B(OH) 2 or Si(OH) 3 ; 2≤n<24; m≤2n-4; o≤n;

[0067] [ii-A1]:

[0068] Among them, 0≤n<24;

[0069] [ii-A2]:

[0070] Wherein, X=F, CI, Br or I; 1≤n<24; m≤2n+1;

[0071] [ii-A3]:

[0072] Wherein, Y=O, N, NH or S; 1≤n<24; o≤n;

[0073] [ii-A4]: Wherein, X=F, CI, Br or I; Y=O, N, NH or S; 1≤n<24; m≤2n+1; o≤n; [ii-A5]: Among them, 2≤n<24;

[0074] [ii-A6]: Wherein, X=F, CI, Br or I; 2≤n<24; m≤2n-1;

[0075] [ii-A7]: Wherein, Y=O, N, NH or S; 2≤n<24; o≤n;

[0076] [ii-A8]: Wherein, X=F, CI, Br or I; Y=O, N, NH or S; 2≤n<24; m≤2n-1; o≤n;

[0077] [ii-A9]:

[0078] Among them, 2≤n<24;

[0079] [ii-A10]:

[0080] Wherein, X=F, CI, Br or I; 2≤n<24; m≤2n-3;

[0081] [ii-A11]:

[0082] Wherein, Y=O, N, NH or S; 2≤n<24; o≤n; m≤2n-3;

[0083] [ii-A12]:

[0084] Wherein, X=F, CI, Br or I; Y=O, N, NH or S; 2≤n<24; m≤2n-3; o≤n;

[0085] [ii-A13]:

[0086] Among them, R1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 1≤n<24;

[0087] [ii-A14]:

[0088] Wherein, X=F, CI, Br or I; R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 1≤n<24; m≤2n;

[0089] [ii-A15]:

[0090] Wherein, Y=O, N, NH or S;

[0091] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0092] B(OH) 2 or Si(OH) 3 ; 1≤n<24; o≤n;

[0093] [ii-A16]:

[0094] Wherein, X=F, CI, Br or I; Y=O, N, NH or S;

[0095] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0096] B(OH) 2 or Si(OH) 3 ; 1≤n<24; o≤n; m≤2n;

[0097] [ii-A17]:

[0098] Among them, R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 2≤n<24;

[0099] [ii-A18]:

[0100] Wherein, X=F, CI, Br or I; R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH)3 ; 2≤n<24; m≤2n-2;

[0101] [ii-A19]:

[0102] Wherein, Y=O, N, NH or S;

[0103] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0104] B(OH) 2 or Si(OH) 3 ; 2≤n<24; o≤n;

[0105] [ii-A20]:

[0106] Wherein, X=F, CI, Br or I; Y=O, N, NH or S;

[0107] R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0108] B(OH) 2 or Si(OH) 3 ; 2≤n<24; m≤2n-2; o≤n;

[0109] [ii-A21]:

[0110] Among them, R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 2≤n<24;

[0111] [ii-A22]:

[0112] Wherein, X=F, CI, Br or I; R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 0≤n<24; m≤2n-4;

[0113] [ii-A23]:

[0114] Wherein, Y=O, N, NH or S; R 1 =Aryl, CONH 2 、COOH、COO - 、SO 2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - 、B(OH) 2 or Si(OH) 3 ; 2≤n<24; o≤n;

[0115] [ii-A24]:

[0116] Wherein, X=F, CI, Br or I; Y=O, N, NH or S;

[0117] R 1 =Aryl, CONH 2 、COOH、COO - 、SO2 H.SO 2 - 、SO 3 H.SO 3 - ,PO 3 H.PO 3 - ,

[0118] B(OH) 2 or Si(OH) 3 ; 2≤n<24; m≤2n-4; o≤n.

[0119] In combination with the first aspect, according to the above R and R 1 Some specific substitutions, the electrolyte additive contains compounds of formulas [i-B1] to [i-B6] and [ii-B1] to [ii-B4]:

[0120]

[0121]

[0122] 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.

[0123] In combination with the second aspect, preferably, the rechargeable battery electrolyte is understood according to the general meaning in the art, and can be a rechargeable battery electrolyte known in the art, such as ester electrolytes, ether electrolytes, nitrile electrolytes, sulfone electrolytes, aqueous electrolytes, mixed electrolytes, ionic liquid electrolytes, etc.

[0124] 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.

[0125] 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.

[0126] In combination with the third aspect, preferably, the rechargeable battery of the present application contains 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.

[0127] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application include at least:

[0128] The electrolyte additive provided in the first aspect of the present application uses electron-deficient cyclohexaneheximide or cyclopentanepentimide as the structural mother core, and the structural mother core is substituted with -H, C 1 -C 24 The fatty group, C 1 -C 24 Substituted aliphatic groups, C 1 -C 24 The terminal functionalized aliphatic group, C 1 -C 24 The terminal functionalization replaces the planar molecule of the fatty group. On the one hand, it ensures that the additive molecule has multiple coordination centers and a narrow HOMO / LUMO energy band gap, which can effectively make the additive adsorb on the surface of the positive and negative electrodes of the battery and participate in the generation of CEI and SEI interface films for fast ion conduction, thereby improving the cycle life and other performance of the battery; on the other hand, it can effectively regulate the uniformity of the accumulation of the additive molecules at the interface of the positive and negative electrodes of the battery and the efficiency and stability of the 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 dendrite; in addition, based on the above two advantages, the additive has an accurate structure, simple preparation, comprehensive functions, good solubility, is conducive to industrial production and application, and has a good single application effect.

[0129] The rechargeable battery electrolyte provided in the second aspect of the present application contains the electrolyte additive, and based on the electrolyte additive, it has the effect of effectively improving the battery cycle life and having good industrial application effects. Therefore, when the rechargeable battery electrolyte of the present application contains the electrolyte additive, it can not only effectively inhibit the side reactions related to the electrolyte and the positive and negative electrodes of the battery, thereby improving the battery kinetic performance while reducing the consumption of the electrolyte, but also effectively promote the low-cost commercial application of the electrolyte additive.

[0130] The rechargeable battery provided in the third aspect of the present application uses the rechargeable battery electrolyte as the electrolyte, based on the performance characteristics of the rechargeable battery electrolyte that inhibits the electrolyte from causing related side reactions with the positive and negative electrodes of the battery. Therefore, when the rechargeable battery contains the rechargeable battery electrolyte, the dynamic performance of the battery can be significantly improved, so that the rechargeable battery has a longer cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0131] 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.

[0132] Figure 1-1The ester-containing LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC1 and modified electrolyte EC1;

[0133] Figure 1-2 The ester-containing LiPF 6 Performance test diagram of electrolyte AEC1 and lithium manganese oxide / Li battery containing modified electrolyte EC1;

[0134] Figure 2-1 Cycling curves of Li / Li batteries containing ether-based LiTFSI electrolyte AEC2 and modified electrolyte EC2 provided in the examples of the present application;

[0135] Figure 2-2 Performance test diagram of lithium iron phosphate lithium / Li battery containing ether LiTFSI electrolyte AEC2 and modified electrolyte EC2 provided in the embodiments of the present application;

[0136] Figure 3-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC3 provided in the examples of the present application;

[0137] Figure 3-2 It is a performance test diagram of a ternary lithium (NCM811) / Li battery containing a nitrile LiTFSI electrolyte AEC3 and a modified electrolyte EC3 provided in an embodiment of the present application;

[0138] Figure 4-1 The ester-containing LiPF 6 Cycling curves of Li / Li batteries with electrolyte AEC1 and modified electrolyte EC4;

[0139] Figure 4-2 The ester-containing LiPF 6 Performance test diagram of lithium iron phosphate / Li battery containing electrolyte AEC1 and modified electrolyte EC4;

[0140] Figure 5-1 Cycling curves of Li / Li batteries containing ether-based LiTFSI electrolyte AEC2 and modified electrolyte EC5 provided in the examples of the present application;

[0141] Figure 5-2 Performance test diagram of lithium iron phosphate lithium / Li battery containing ether-based LiTFSI electrolyte AEC2 and modified electrolyte EC5 provided in the embodiments of the present application;

[0142] Figure 6-1Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC6 provided in the examples of the present application;

[0143] Figure 6-2 Performance test diagram of a ternary lithium (NCM811) / Li battery containing a nitrile LiTFSI electrolyte AEC3 and a modified electrolyte EC6 provided in an embodiment of the present application;

[0144] Figure 7-1 The ester-containing LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC1 and modified electrolyte EC7;

[0145] Figure 7-2 The ester-containing LiPF provided in the embodiment of the present application 6 Performance test diagram of lithium cobalt oxide / Li battery containing electrolyte AEC1 and modified electrolyte EC7;

[0146] Figure 8-1 Cycling curves of Li / Li batteries containing ether-based LiTFSI electrolyte AEC2 and modified electrolyte EC8 provided in the examples of the present application;

[0147] Figure 8-2 Performance test diagram of lithium iron phosphate lithium / Li battery containing ether LiTFSI electrolyte AEC2 and modified electrolyte EC8 provided in the embodiments of the present application;

[0148] Figure 9-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC9 provided in the examples of the present application;

[0149] Figure 9-2 This is a performance test diagram of a ternary lithium (NCM811) / Li battery containing a nitrile LiTFSI electrolyte AEC3 and a modified electrolyte EC9 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0150] 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.

[0151] 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 parameters of the same battery mold described in the examples of this application are 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 sheet diameter is 1 cm, lithium manganese oxide surface loading is 1.2 mg·cm -2 , lithium foil diameter 1cm); lithium iron phosphate / Li mold full battery (positive electrode sheet diameter 1cm, lithium iron phosphate surface loading 1.2mg 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).

[0152] Example 1

[0153] This embodiment provides a method for preparing a modified electrolyte EC1 containing cyclohexaneheximide, comprising the following steps:

[0154] Dissolve 0.8 g of cyclohexane hexamethyleneimine in 1 L of ester LiPF 6 The modified electrolyte EC1 is obtained by adding electrolyte AEC1. 6 The electrolyte AEC1 contains 1mmol / L LiPF 6 , the solvent is dimethyl carbonate, ethyl methyl carbonate and ethylene carbonate in a volume ratio of 1:1:1; the chemical structure of cyclohexaneheximide is shown in i-B1:

[0155] i-B1:

[0156] In order to study the addition of cyclohexane hexamethyleneimine to ester LiPF 6 The influence of electrolyte performance, this embodiment carries out the following two experiments:

[0157] Experiment 1-1

[0158] Take two identical Li / Li button-type symmetrical mold full cells and add 0.1 mL of ester LiPF into each of the two mold full cells. 6 After adding electrolyte AEC1 and 0.1 mL of modified electrolyte EC1, 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 1-1As shown. Among them, Figure 1-1 Containing ester LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC1 and modified electrolyte EC1.

[0159] according to Figure 1-1 It can be seen that the ester-containing LiPF 6 Compared with the Li / Li battery with electrolyte AEC1, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC1 was reduced from 0.8V to 0.1V, and the stable cycle time was increased from 85h to more than 260h, indicating that the ester LiPF 6 Adding cyclohexaneheximide to the electrolyte can reduce the polarization voltage and significantly improve the cycle stability of Li / Li batteries.

[0160] Experiment 1-2

[0161] Take two identical lithium 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 AEC1 and modified electrolyte EC1, 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 1-2 As shown. Among them, Figure 1-2 Containing ester LiPF 6 Performance test diagram of lithium manganese oxide / Li battery containing electrolyte AEC1 and modified electrolyte EC1.

[0162] according to Figure 1-2 It can be seen that at a current density of 10C, the capacity of the lithium manganese oxide / Li battery containing the modified electrolyte EC1 is lower than that containing the ester LiPF 6 The capacity of lithium manganese oxide / Li battery with electrolyte AEC1 is increased by nearly 30mAh / g; at the same time, it contains ester LiPF 6 The lithium manganese oxide / Li battery with electrolyte AEC1 can stably cycle for about 600 cycles. After 600 cycles, the battery capacity shows obvious attenuation, with obvious overcharge and overdischarge phenomena. The lithium manganese oxide / Li battery with modified electrolyte EC1 can stably cycle for more than 1000 cycles, and the coulomb efficiency remains close to 100%. It can be seen that compared with the ester LiPF 6 Compared with the lithium manganese oxide / Li battery containing electrolyte AEC1, the coulombic efficiency, cycle stability, capacity and retention rate of the lithium manganese oxide / Li battery containing modified electrolyte EC1 are significantly improved, indicating that ester LiPF 6 Adding cyclohexaneheximide to the electrolyte can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0163] Example 2

[0164] This embodiment provides a method for preparing a modified electrolyte EC2 containing a hexabutylcyclohexaneheximide additive, comprising the following steps:

[0165] 1.0 g of hexabutylcyclohexaneheximide was dissolved in 1 L of ether LiTFSI electrolyte AEC2 to obtain modified electrolyte EC2. The ether LiTFSI electrolyte AEC2 contained 1 mmol / L LiTFSI, and the solvent was 1,3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1; the chemical structures of hexabutylcyclohexaneheximide are shown in i-B2:

[0166] i-B2:

[0167] In order to study the effect of adding hexabutylcyclohexaneheximide on the performance of ether-based LiTFSI electrolyte, the following two experiments were conducted in this example:

[0168] Experiment 2-1

[0169] Take two identical Li / Li button-type symmetrical cells and add 0.1 mL of ether 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 ether LiTFSI electrolyte AEC2 and modified electrolyte EC2.

[0170] according to Figure 2-1 It can be seen that compared with the Li / Li battery containing the ether LiTFSI electrolyte AEC2, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC2 is reduced from 0.8V to 0.2V, and the stable cycle time is increased from 80h to more than 235h, indicating that the addition of hexabutylcyclohexaneheximide to the ether LiTFSI electrolyte AEC2 can reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0171] Experiment 2-2

[0172] Take two identical lithium iron phosphate / Li mold full cells, and respectively load 0.1mL of ether 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 10C. The results are as follows: Figure 2-2 As shown. Among them, Figure 2-2Performance test diagram of lithium iron phosphate / Li battery containing ether LiTFSI electrolyte AEC2 and modified electrolyte EC2.

[0173] according to Figure 2-2 It can be seen that at a current density of 10C, the capacity of the lithium iron phosphate / Li battery containing the modified electrolyte EC2 is nearly 30mAh / g higher than that of the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2; at the same time, the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2 can be stably cycled for about 600 cycles, and the battery capacity shows obvious attenuation after 600 cycles, with obvious overcharge and overdischarge phenomenon, while the lithium iron phosphate / Li battery containing the modified electrolyte EC2 has a stable cycle of more than 1000 cycles, and the coulombic efficiency remains close to 100%. It can be seen that compared with the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2, the coulombic efficiency, cycle stability, capacity and retention rate of the lithium iron phosphate / Li battery containing the modified electrolyte EC2 are significantly improved, indicating that the addition of hexabutylcyclohexaneheximide to the ether LiTFSI electrolyte AEC2 can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0174] Example 3

[0175] This embodiment provides a method for preparing a modified electrolyte EC3 containing hexa(2-methoxyethyl)cyclopentanehexamethyleneimine, comprising the following steps:

[0176] 1.0 g of hexamethoxyethylcyclopentane hexamethyleneimine was dissolved in 1 L of nitrile LiTFSI electrolyte AEC 3 to obtain modified electrolyte EC3. The nitrile LiTFSI electrolyte AEC3 contains 1 mmol / L LiTFSI, and the solvent is acetonitrile and succinonitrile in a volume ratio of 2:1; the chemical structure of hexamethoxyethylcyclopentane hexamethyleneimine is shown in i-B3:

[0177] i-B3:

[0178] In order to study the effect of adding hexa(2-methoxyethyl)cyclopentanehexamethyleneimine on the performance of nitrile LiTFSI electrolyte, the following two experiments were conducted in this example:

[0179] Experiment 3-1

[0180] Take two identical Li / Li button-type symmetrical mold full cells, and add 0.1 mL of nitrile LiTFSI electrolyte AEC3 and 0.1 mL of modified electrolyte EC3 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 3-1 As shown. Among them, Figure 3-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC3.

[0181] according to Figure 3-1 It can be seen that compared with the Li / Li battery containing the nitrile LiTFSI electrolyte AEC3, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC3 is reduced from 0.8V to 0.1V, and the stable cycle time is increased from 82h to more than 250h, indicating that the addition of hexa(2-methoxyethylcyclopentaneheximide) to the nitrile LiTFSI electrolyte can reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0182] Experiment 3-2

[0183] Take two identical ternary lithium (NCM811) / Li mold full cells, and respectively load 0.1mL of nitrile LiTFSI electrolyte AEC3 and 0.1mL of modified electrolyte EC3 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 3-2 As shown. Among them, Figure 3-2 This is a performance test diagram of ternary lithium (NCM811) / Li battery containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC3.

[0184] according to Figure 3-2 It can be seen that at a current density of 10C, the capacity of the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC3 is nearly 20mAh / g higher than that of the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3; at the same time, the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3 can be stably cycled for about 600 cycles. After 600 cycles, the battery capacity shows obvious decay, with obvious overcharge and over-discharge phenomena, while the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC3 has a stable cycle of more than 1000 cycles, and the coulombic efficiency remains close to 100%. It can be seen that compared with the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3, the coulombic efficiency, cycle stability, capacity and retention rate of the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC1 are significantly improved, indicating that the addition of hexa(2-methoxyethylcyclopentaneheximide) to the nitrile LiTFSI electrolyte can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0185] Example 4

[0186] This embodiment provides a method for preparing a modified electrolyte EC4 containing hexa(3-butenyl)cyclohexaneheximide, comprising the following steps:

[0187] Dissolve 80 g of hexa-3-butenylcyclohexaneheximide in 1 L of ester LiPF 6 The modified electrolyte EC4 is obtained by adding electrolyte AEC1. 6 The electrolyte AEC1 contains 1mmol / L LiPF 6 , the solvent is dimethyl carbonate, ethyl methyl carbonate and ethylene carbonate in a volume ratio of 1:1:1; the chemical structure of hexa-3-butenylcyclohexaneheximide is shown in i-B4:

[0188] i-B4:

[0189] In order to study the addition of hexa-3-butenylcyclohexaneheximide to ester LiPF 6 The influence of electrolyte performance, this embodiment carries out the following two experiments:

[0190] Experiment 4-1

[0191] Take two identical Li / Li button-type symmetrical mold full cells and add 0.1 mL of ester LiPF into each mold full cell. 6 After adding electrolyte AEC1 and 0.1 mL of modified electrolyte EC4, 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 4-1 As shown. Among them, Figure 4-1 Containing ester LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC1 and modified electrolyte EC4.

[0192] according to Figure 4-1 It can be seen that the ester-containing LiPF 6 Compared with the Li / Li battery with electrolyte AEC1, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC4 was reduced from 0.7V to 0.2V, and the stable cycle time was increased from 80h to more than 280h, indicating that the ester LiPF 6 Adding hexa(3-butenylcyclohexaneheximide) into the electrolyte can reduce the polarization voltage and significantly improve the cycle stability of Li / Li batteries.

[0193] Experiment 4-2

[0194] Take two identical lithium iron phosphate / Li mold full cells and add 0.1 mL of ester LiPF into each of the two mold full cells. 6After adding 0.1 mL of electrolyte AEC1 and modified electrolyte EC4, 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 4-2 As shown. Among them, Figure 4-2 Containing ester LiPF 6 Performance test diagram of lithium iron phosphate / Li battery containing electrolyte AEC1 and modified electrolyte EC4.

[0195] according to Figure 4-2 It can be seen that at a current density of 10C, the capacity of the lithium iron phosphate / Li battery containing the modified electrolyte EC1 is lower than that containing the ester LiPF 6 The capacity of lithium iron phosphate / Li battery with electrolyte AEC1 is increased by nearly 10mAh / g; containing ester LiPF 6 The lithium iron phosphate / Li battery with electrolyte AEC1 can be stably cycled for about 600 cycles. After 600 cycles, the battery capacity shows obvious attenuation, with obvious overcharge and overdischarge phenomena. The lithium iron phosphate / Li battery with modified electrolyte EC1 can be stably cycled for more than 1000 cycles, and the coulombic efficiency remains close to 100%. 6 Compared with the lithium iron phosphate / Li battery containing electrolyte AEC1, the coulombic efficiency, cycle stability, capacity and retention rate of the lithium iron phosphate / Li battery containing modified electrolyte EC1 are significantly improved, indicating that ester LiPF 6 Adding hexa(3-butenyl)cyclohexaneheximide to the electrolyte can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0196] Example 5

[0197] This embodiment provides a method for preparing a modified electrolyte EC5 containing hexa-4-butyrylcyclohexaneheximide, comprising the following steps:

[0198] 5.0 g of hexa-4-butyric acid cyclohexane hexaimide was dissolved in 1 L of ether LiTFSI electrolyte AEC2 to obtain modified electrolyte EC5. The ether LiTFSI electrolyte AEC2 contains 1 mmol / L LiTFSI, and the solvent is 1,3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1; the chemical structure of hexa-4-butyric acid cyclohexane hexaimide is shown in i-B5:

[0199] i-B5:

[0200] In order to study the effect of adding hexa-4-butyric acid cyclohexaneheximide on the performance of ether-based LiTFSI electrolyte, the following two experiments were conducted in this example:

[0201] Experiment 5-1

[0202] Take two identical Li / Li coin-type symmetric full cells, and after filling 0.1 mL of the ether-based LiTFSI electrolyte AEC2 and 0.1 mL of the modified electrolyte EC5 into the two full cells respectively, test the cycling stability of the two cells at a areal capacity of 1 mAh·cm -2 and a current density of 2 mA·cm -2 . The results are as Figure 5-1 shown. Among them, Figure 5-1 are the cycling curves of the Li / Li cells containing the ether-based LiTFSI electrolyte AEC2 and the modified electrolyte EC5.

[0203] According to Figure 5-1 , compared with the Li / Li cell containing the ether-based LiTFSI electrolyte AEC2, the initial polarization voltage of the Li / Li cell containing the modified electrolyte EC5 decreases from 0.8 V to 0.3 V, and the stable cycling duration increases from 80 h to more than 250 h, indicating that adding hexakis(4-butylcyclohexyl)hexaimine to the ether-based LiTFSI electrolyte AEC2 can reduce the polarization voltage and significantly improve the cycling stability of the Li / Li cell.

[0204] Experiment 5-2

[0205] Take two identical lithium iron phosphate / Li full cells, and after filling 0.1 mL of the ether-based LiTFSI electrolyte AEC2 and 0.1 mL of the modified electrolyte EC5 into the two full cells respectively, test the Coulombic efficiency, cycling stability, capacity and retention rate of the two cells at a current density of 10C. The results are as Figure 5-2 shown. Among them, Figure 5-2 are the performance test diagrams of the lithium iron phosphate / Li cells containing the ether-based LiTFSI electrolyte AEC2 and the modified electrolyte EC5.

[0206] According to Figure 5-2It can be seen that at a current density of 10C, the capacity of the lithium iron phosphate / Li battery containing the modified electrolyte EC5 is nearly 30mAh / g higher than that of the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2; at the same time, the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2 can stably cycle for about 600 cycles, and the battery capacity shows obvious attenuation after 600 cycles, with obvious overcharge and overdischarge phenomenon, while the lithium iron phosphate / Li battery containing the modified electrolyte EC5 has a stable cycle of more than 1000 cycles, and the coulombic efficiency remains close to 100%. It can be seen that compared with the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2, the coulombic efficiency, cycle stability, capacity and retention rate of the lithium manganate / Li battery containing the modified electrolyte EC5 are significantly improved, indicating that the addition of hexa-4-butyric acid cyclohexane hexamethyleneimine to the ether LiTFSI electrolyte can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0207] Example 6

[0208] This embodiment provides a method for preparing a modified electrolyte EC6 containing hexafluoro-1-yne-4-phosphocyclopentaimide, comprising the following steps:

[0209] 9.5 g of hexafluoro-1-yne-4-phosphate cyclopentane pentaimide was dissolved in 1 L of nitrile LiTFSI electrolyte AEC3 to obtain modified electrolyte EC6. The nitrile LiTFSI electrolyte AEC3 contained 1 mmol / L LiTFSI, and the solvent was acetonitrile and succinonitrile in a volume ratio of 2:1; the chemical structure of hexafluoro-1-yne-4-phosphate cyclopentane pentaimide is shown in i-B6:

[0210] i-B6:

[0211] In order to study the effect of adding hexafluoro-1-yne-4-phosphate cyclopentane pentaimide on the performance of nitrile LiTFSI electrolyte, the following two experiments were conducted in this example:

[0212] Experiment 6-1

[0213] Take two identical Li / Li button-type symmetrical mold full cells, and add 0.1 mL of nitrile LiTFSI electrolyte AEC3 and 0.1 mL of modified electrolyte EC6 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 6-1 As shown. Among them, Figure 6-1Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC6.

[0214] according to Figure 6-1 It can be seen that compared with the Li / Li battery containing the nitrile LiTFSI electrolyte AEC3, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC6 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 hexafluoro-1-yne-4-phosphate cyclopentanepentaimide to the nitrile LiTFSI electrolyte can reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0215] Experiment 6-2

[0216] Take two identical ternary lithium (NCM811) / Li mold full cells, and respectively load 0.1mL of nitrile LiTFSI electrolyte AEC3 and 0.1mL of modified electrolyte EC6 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 6-2 As shown. Among them, Figure 6-2 This is a performance test diagram of ternary lithium (NCM811) / Li battery containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC6.

[0217] according to Figure 6-2 It can be seen that at a current density of 10C, the capacity of the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC6 is nearly 30mAh / g higher than that of the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3; at the same time, the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3 can be stably cycled for about 600 cycles. After 600 cycles, the battery capacity shows obvious decay, with obvious overcharge and over-discharge phenomena, while the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC6 has a stable cycle of more than 1000 cycles, and the coulombic efficiency remains close to 100%. It can be seen that compared with the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3, the coulombic efficiency, cycle stability, capacity and retention rate of the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC6 are significantly improved, indicating that the addition of hexafluoro-1-yne-4-phosphate cyclopentanepentaimide to the nitrile LiTFSI electrolyte can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0218] Example 7

[0219] This embodiment provides a method for preparing a modified electrolyte EC7 containing pentafluorobutylcyclopentafluoropentaimide, comprising the following steps:

[0220] Dissolve 45 g of heptafluorobutylcyclopentafluoropentaimide in 1 L of ester LiPF 6 The modified electrolyte EC7 is obtained by adding electrolyte AEC1. 6 The electrolyte AEC1 contains 1mmol / L LiPF 6 , the solvent is dimethyl carbonate, ethyl methyl carbonate and ethylene carbonate in a volume ratio of 1:1:1; the chemical structure of pentafluorobutylcyclopentafluoropentaimide is shown in ii-B1:

[0221] ii-B1:

[0222] In order to study the addition of pentafluorobutyl cyclopentafluoroimide to ester LiPF 6 The influence of electrolyte performance, this embodiment carries out the following two experiments:

[0223] Experiment 7-1

[0224] Take two identical Li / Li button-type symmetrical mold full cells and add 0.1 mL of ester LiPF into each of the two mold full cells. 6 After adding electrolyte AEC1 and 0.1 mL of modified electrolyte EC7, 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 7-1 As shown. Among them, Figure 7-1 Containing ester LiPF 6 Cycling curves of Li / Li cells with electrolyte AEC1 and modified electrolyte EC7.

[0225] according to Figure 7-1 It can be seen that the ester-containing LiPF 6 Compared with the Li / Li battery with electrolyte AEC1, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC7 was reduced from 0.8V to 0.3V, and the stable cycle time was increased from 80h to more than 255h, indicating that the ester LiPF 6 Adding pentafluorobutylcyclopentafluoroimide to the electrolyte can reduce the polarization voltage and significantly improve the cycle stability of Li / Li batteries.

[0226] Experiment 7-2

[0227] Take two identical lithium cobalt oxide / Li mold full cells and add 0.1 mL of ester LiPF into each of the two mold full cells. 6After adding 0.1 mL of electrolyte AEC1 and modified electrolyte EC7, 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 7-2 As shown. Among them, Figure 7-2 Containing ester LiPF 6 Performance test diagram of lithium cobalt oxide / Li battery containing electrolyte AEC1 and modified electrolyte EC7.

[0228] according to Figure 7-2 It can be seen that at a current density of 10C, the capacity of the lithium cobalt oxide / Li battery containing the modified electrolyte EC7 is higher than that containing the ester LiPF 6 The capacity of lithium cobalt oxide / Li battery with electrolyte AEC1 is increased by nearly 30mAh / g; at the same time, it contains ester LiPF 6 The lithium cobalt oxide / Li battery with electrolyte AEC1 can stably cycle for about 650 cycles. After 650 cycles, the battery capacity shows obvious attenuation, with obvious overcharge and overdischarge phenomena. The lithium cobalt oxide / Li battery with modified electrolyte EC7 can stably cycle for more than 1000 cycles, and the coulomb efficiency remains close to 100%. 6 Compared with the lithium cobalt oxide / Li battery containing electrolyte AEC1, the coulombic efficiency, cycle stability, capacity and retention rate of the lithium cobalt oxide / Li battery containing modified electrolyte EC7 are significantly improved, indicating that ester LiPF 6 Adding pentafluorobutylcyclopentafluoroimide to the electrolyte can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0229] Example 8

[0230] This embodiment provides a method for preparing a modified electrolyte EC8 containing 2-(2-fluorocyclobutane-1-amino)ethylcyclopentanepentaimide, comprising the following steps:

[0231] 9.1 g of 2-(2-fluorocyclobutane-1-amino)ethylcyclopentane pentamethyleneimine was dissolved in 1 L of ether LiTFSI electrolyte AEC2 to obtain modified electrolyte EC8. The ether LiTFSI electrolyte AEC2 contained 1 mmol / L LiTFSI, and the solvent was 1,3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1; the chemical structure of 2-(2-fluorocyclobutane-1-amino)ethylcyclopentane pentamethyleneimine is shown in ii-B2:

[0232] ii-B2:

[0233] In order to study the effect of adding penta-2-(2-fluorocyclobutane-1-amino)ethylcyclopentane pentaimide on the performance of ether-based LiTFSI electrolyte, the following two experiments were conducted in this example:

[0234] Experiment 8-1

[0235] Take two identical Li / Li button-type symmetrical mold full cells, and respectively load 0.1 mL of ether LiTFSI electrolyte AEC2 and 0.1 mL of modified electrolyte EC8 into the two mold full cells. -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 ether LiTFSI electrolyte AEC2 and modified electrolyte EC8.

[0236] according to Figure 8-1 It can be seen that compared with the Li / Li battery containing the ether LiTFSI electrolyte AEC2, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC8 is reduced from 0.8V to 0.3V, and the stable cycle time is increased from 80h to more than 275h, indicating that the addition of 2-(2-fluorocyclobutane-1-amino)ethylcyclopentanepentaimide to the ether LiTFSI electrolyte AEC2 can reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0237] Experiment 8-2

[0238] Take two identical lithium iron phosphate / Li mold full cells, and respectively load 0.1mL of ether 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 10C. The results are as follows: Figure 8-2 As shown. Among them, Figure 8-2 Performance test diagram of lithium iron phosphate lithium / Li battery containing ether LiTFSI electrolyte AEC2 and modified electrolyte EC8.

[0239] according to Figure 8-2It can be seen that at a current density of 10C, the capacity of the lithium iron phosphate / Li battery containing the modified electrolyte EC8 is nearly 30mAh / g higher than that of the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2; at the same time, the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2 can be stably cycled for about 650 cycles. After 650 cycles, the battery capacity shows obvious decay, with obvious overcharge and over-discharge phenomena, while the lithium iron phosphate / Li battery containing the modified electrolyte EC8 has a stable cycle of more than 1000 cycles, and the coulombic efficiency remains close to 100%. It can be seen that compared with the lithium iron phosphate / Li battery containing the ether LiTFSI electrolyte AEC2, the coulombic efficiency, cycle stability, capacity and retention rate of the lithium iron phosphate / Li battery containing the modified electrolyte EC8 are significantly improved, indicating that the addition of penta-2-(2-fluorocyclobutane-1-amino)ethylcyclopentanepentaimide to the ether LiTFSI electrolyte AEC2 can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0240] Example 9

[0241] This embodiment provides a method for preparing a modified electrolyte EC9 containing penta-2-(3-fluoro-2-formyl-1-pyrrolidinyl)ethylcyclopentanepentaimide, comprising the following steps:

[0242] 1.0 g of pentadienyl 2-(3-fluoro-2-formyl-1-pyrrolidinyl)ethyl cyclopentadienyl pentamethyleneimine was dissolved in 1 L of nitrile LiTFSI electrolyte to obtain modified electrolyte EC9. Among them, nitrile LiTFSI electrolyte AEC3 contains 1 mmol / L LiTFSI, and the solvent is acetonitrile and succinonitrile in a volume ratio of 2:1; the chemical structure of pentadienyl 2-(3-fluoro-2-formyl-1-pyrrolidinyl)ethyl cyclopentadienyl pentamethyleneimine is shown in ii-B3:

[0243] ii-B3:

[0244] In order to study the effect of adding penta-2-(3-fluoro-2-formyl-1-pyrrolidinyl)ethylcyclopentanepentaimide on the performance of nitrile LiTFSI electrolyte, the following two experiments were conducted in this example:

[0245] Experiment 9-1

[0246] Take two identical Li / Li button-type symmetrical mold full cells, and respectively load 0.1 mL of nitrile LiTFSI electrolyte AEC3 and 0.1 mL of modified electrolyte EC9 into the two mold full cells. -2 The surface loading and 2 mA·cm -2 The cycle stability of the two batteries was tested at a current density of Figure 9-1As shown. Among them, Figure 9-1 Cycling curves of Li / Li batteries containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC9.

[0247] according to Figure 9-1 It can be seen that compared with the Li / Li battery containing the nitrile LiTFSI electrolyte AEC3, the initial polarization voltage of the Li / Li battery containing the modified electrolyte EC9 is reduced from 0.8V to 0.2V, and the stable cycle time is increased from 80h to more than 245h, indicating that the addition of penta-2-(3-fluoro-2-formyl-1-pyrrolidinyl)ethylcyclopentanepentaimide to the nitrile LiTFSI electrolyte can reduce the polarization voltage and significantly improve the cycle stability of the Li / Li battery.

[0248] Experiment 9-2

[0249] Take two identical ternary lithium (NCM811) / Li mold full cells, and respectively load 0.1mL of nitrile LiTFSI electrolyte AEC3 and 0.1mL of modified electrolyte EC9 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 Figure 9-2 As shown. Among them, Figure 9-2 Performance test diagram of ternary lithium (NCM811) / Li battery containing nitrile LiTFSI electrolyte AEC3 and modified electrolyte EC9.

[0250] according to Figure 9-2 It can be seen that at a current density of 10C, the capacity of the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC3 is nearly 30mAh / g higher than that of the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3; the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3 can be stably cycled for about 650 cycles, and the battery capacity after 650 cycles shows obvious decay, with obvious overcharge and over-discharge phenomena, while the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC3 has a stable cycle of more than 1000 cycles, and the coulombic efficiency remains close to 100%. It can be seen that compared with the ternary lithium (NCM811) / Li battery containing the nitrile LiTFSI electrolyte AEC3, the coulombic efficiency, cycle stability, capacity and retention rate of the ternary lithium (NCM811) / Li battery containing the modified electrolyte EC1 are significantly improved, indicating that the addition of penta-2-(3-fluoro-2-formyl-1-pyrrolidinyl)ethylcyclopentanepentaimide to the nitrile LiTFSI electrolyte can significantly improve the coulombic efficiency, cycle stability, capacity and retention rate of the battery.

[0251] 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.

[0252] 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 It has a chemical structure shown in any one of formulas [i-B1] to [i-B6] and formulas [ii-B1] to [ii-B3]:

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 2-3.

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

Images