WO2023179456A1

WO2023179456A1 - Non-aqueous electrolyte and secondary battery

Info

Publication number: WO2023179456A1
Application number: PCT/CN2023/081992
Authority: WO
Inventors: 钱韫娴; 胡时光; 邓永红; 林雄贵; 孙桂岩; 皮琛琦
Original assignee: 深圳新宙邦科技股份有限公司
Priority date: 2022-03-25
Filing date: 2023-03-16
Publication date: 2023-09-28
Also published as: CN114725512A

Abstract

Disclosed are a non-aqueous electrolyte and a secondary battery, wherein the non-aqueous electrolyte comprises a non-aqueous organic solvent, an electrolyte salt and an additive; the non-aqueous organic solvent comprises a cyclic carbonate, and the mass percentage content of the cyclic carbonate in the non-aqueous organic solvent is 10-40%; the additive comprises a first additive as represented by formula I and a second additive as represented by formula II, and the reduction potential of the first additive is 0.95 V or more; and the non-aqueous electrolyte satisfies the following conditions: 0.05% ≤ A ≤ 1.8%; 0.01% ≤ B ≤ 0.2%; and 0.15 ≤ A/(B*10) ≤ 10.5.

Description

非水电解液及二次电池Non-aqueous electrolytes and secondary batteries

相关申请的交叉引用Cross-references to related applications

本申请要求在2022年03月25日在中国提交的中国专利申请号202210302910.X的优先权，其全部内容通过引用并入本文。This application claims priority to Chinese Patent Application No. 202210302910.X filed in China on March 25, 2022, the entire content of which is incorporated herein by reference.

技术领域Technical field

本申请属于储能电池器件技术领域，具体涉及一种非水电解液及二次电池。This application belongs to the technical field of energy storage battery devices, and specifically relates to a non-aqueous electrolyte and a secondary battery.

背景技术Background technique

锂离子电池具有能量密度高、循环寿命长、绿色环保等优点，使得锂离子电池已经被广泛应用于3C数码设备和新能源动力汽车领域，但动力领域的终端用户仍对于续航里程的提升存在着迫切要求，因此进一步提高动力电池的能量密度是锂离子电池领域始终不变的追求之一。然而高温存储产气和阻抗增长问题始终是高能量密度动力电池体系面临的主要问题之一。在高温条件下，会加速电解液在电极材料表面的反应，从而导致电解液分解产生气体，产生的气体会导致电池发生鼓包膨胀，容易造成电池破裂，电解液泄露，从而存在较大的安全隐患，同时，由于电解液在电极表面的持续分解，降低了电解液中有效锂盐成分，导致了电极表面的钝化膜厚度逐渐增大，电解液自身的离子导电能力下降，进而导致了电池阻抗增长的问题，使得电池容量下降。Lithium-ion batteries have the advantages of high energy density, long cycle life, and green environmental protection. As a result, lithium-ion batteries have been widely used in the fields of 3C digital equipment and new energy vehicles. However, end users in the power field still have concerns about improving the cruising range. Therefore, further improving the energy density of power batteries is one of the constant pursuits in the field of lithium-ion batteries. However, the problems of high-temperature storage gas production and impedance growth have always been one of the main problems faced by high-energy-density power battery systems. Under high temperature conditions, the reaction of the electrolyte on the surface of the electrode material will be accelerated, causing the electrolyte to decompose and produce gas. The gas generated will cause the battery to bulge and bulge, which may easily cause the battery to rupture and the electrolyte to leak, thus posing a major safety hazard. , at the same time, due to the continuous decomposition of the electrolyte on the electrode surface, the effective lithium salt component in the electrolyte is reduced, resulting in a gradual increase in the thickness of the passivation film on the electrode surface, and a decrease in the ionic conductivity of the electrolyte itself, which in turn leads to a decrease in battery impedance. The problem of growth causes the battery capacity to decrease.

如何抑制电池在高温条件下的气体生成和阻抗增长是电池领域亟需解决的问题。How to suppress the gas generation and impedance growth of batteries under high temperature conditions is an urgent problem that needs to be solved in the battery field.

发明内容Contents of the invention

一方面，本申请实施例提供了一种非水电解液，包括非水有机溶剂、电解质盐和添加剂，所述非水有机溶剂包括环状碳酸酯，所述环状碳酸酯在所述非水有机溶剂中的质量百分含量为10～40％；On the one hand, embodiments of the present application provide a non-aqueous electrolyte solution, including a non-aqueous organic solvent, an electrolyte salt and an additive. The non-aqueous organic solvent includes a cyclic carbonate, and the cyclic carbonate is in the non-aqueous The mass percentage content of the organic solvent is 10 to 40%;

所述添加剂包括式I所示的第一添加剂和式II所示的第二添加剂，所述第一添加剂的还原电位在0.95V以上；
The additive includes a first additive represented by Formula I and a second additive represented by Formula II, and the reduction potential of the first additive is above 0.95V;

其中，R₁选自C或O，R₂选自R₃选自亚甲基、R₄选自H、且R₂、R₃和R₄中至少含有一个硫原子；
Among them, R ₁ is selected from C or O, and R ₂ is selected from R ₃ is selected from methylene, R ₄ is selected from H, And R ₂ , R ₃ and R ₄ contain at least one sulfur atom;

其中，R₅选自C1-C5的饱和烃基、C1-C5的不饱和烃基、C1-C5的卤代烃基、芳香基和-Si(C_mH_2m+1)₃及其卤代物，m为1～3的自然数；Among them, R ₅ is selected from C1-C5 saturated hydrocarbon groups, C1-C5 unsaturated hydrocarbon groups, C1-C5 halogenated hydrocarbon groups, aromatic groups and -Si(C _m H _2m+1 ) ₃ and its halides, m is Natural numbers from 1 to 3;

所述非水电解液满足以下条件：
0.05％≤A≤1.8％；
0.01％≤B≤0.2％；
0.15≤A/(B*10)≤10.5；The non-aqueous electrolyte meets the following conditions:
0.05%≤A≤1.8%;
0.01%≤B≤0.2%;
0.15≤A/(B*10)≤10.5;

其中，A为非水电解液中第一添加剂的质量百分含量，单位为％；Among them, A is the mass percentage of the first additive in the non-aqueous electrolyte, in %;

B为非水电解液中第二添加剂的质量百分含量，单位为％；B is the mass percentage of the second additive in the non-aqueous electrolyte, in %;

所述非水电解液在25℃下的电导率为7mS/cm～10.5mS/cm，且所述非水电解液中甲醇和乙二醇的总醇含量在500ppm及以下。The non-aqueous electrolyte has a conductivity of 7mS/cm～10.5mS/cm at 25°C, and the non-aqueous electrolyte The total alcohol content of methanol and ethylene glycol in the solution is 500 ppm and below.

在一些实施例中，所述第一添加剂的还原电位为0.95～1.35V，且非水电解液中第一添加剂的质量百分含量A为0.2％～1.5％。In some embodiments, the reduction potential of the first additive is 0.95-1.35V, and the mass percentage A of the first additive in the non-aqueous electrolyte is 0.2%-1.5%.

在一些实施例中，所述非水电解液满足以下条件：
0.4≤A/(B*10)≤10。In some embodiments, the non-aqueous electrolyte solution satisfies the following conditions:
0.4≤A/(B*10)≤10.

在一些实施例中，所述式I所示的第一添加剂选自以下化合物中的一种或多种：
In some embodiments, the first additive shown in Formula I is selected from one or more of the following compounds:

在一些实施例中，所述式II所示的第二添加剂选自以下化合物中的一种或多种：

In some embodiments, the second additive represented by Formula II is selected from one or more of the following compounds:

在一些实施例中，所述环状碳酸酯选自碳酸乙烯酯、碳酸丙烯酯、氟代碳酸乙烯酯中的至少一种。In some embodiments, the cyclic carbonate is selected from at least one of ethylene carbonate, propylene carbonate, and fluoroethylene carbonate.

在一些实施例中，所述电解质盐选自LiPF₆、LiBOB、LiDFOB、LiDFOP、LiPO₂F₂、LiBF₄、LiSbF₆、LiAsF₆、LiN(SO₂CF₃)₂、LiN(SO₂C₂F₅)₂、LiC(SO₂CF₃)₃、LiN(SO₂F)₂、LiClO₄、LiAlCl₄、LiCF₃SO₃、Li₂B₁₀Cl₁₀、低级脂肪族羧酸锂盐中的至少一种。In some embodiments, the electrolyte salt is selected from LiPF ₆ , LiBOB, LiDFOB, LiDFOP, LiPO ₂ F ₂ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ At least one of F ₅ ) ₂ , LiC(SO ₂ CF ₃ ) ₃ , LiN(SO ₂ F) ₂ , LiClO ₄ , LiAlCl ₄ , LiCF ₃ SO ₃ , Li ₂ B ₁₀ Cl ₁₀ , and lower aliphatic carboxylic acid lithium salts. A sort of.

在一些实施例中，所述非水电解液中还包括第三添加剂，所述第三添加剂包括磺酸内酯类化合物、环状碳酸酯类化合物、二氟磷酸锂和腈类化合物中的至少一种；以所述非水电解液的总质量为100％计，所述第三添加剂的添加量为0.01％～30％。In some embodiments, the non-aqueous electrolyte further includes a third additive, and the third additive includes at least one of sultone compounds, cyclic carbonate compounds, lithium difluorophosphate, and nitrile compounds. One; based on the total mass of the non-aqueous electrolyte being 100%, the addition amount of the third additive is 0.01% to 30%.

在一些实施例中，所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯或1,3-丙烯磺酸内酯中的至少一种；In some embodiments, the sultone compound is selected from at least one of 1,3-propane sultone, 1,4-butane sultone or 1,3-propene sultone. kind;

所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、氟代碳酸乙烯酯或式Ⅲ所示化合物中的至少一种，
The cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate or the compound represented by formula III,

所述式Ⅲ中，R₂₁、R₂₂、R₂₃、R₂₄、R₂₅、R₂₆各自独立地选自氢原子、卤素原子、C1-C5基团中的一种； In the formula III, R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , and R ₂₆ are each independently selected from one of hydrogen atoms, halogen atoms, and C1-C5 groups;

所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的一种或多种。The nitrile compound is selected from succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelonitrile, and sebaconitrile. of one or more.

另一方面，本申请实施例提供了一种二次电池，包括正极、负极以及如上所述的非水电解液。On the other hand, embodiments of the present application provide a secondary battery including a positive electrode, a negative electrode and the non-aqueous electrolyte as described above.

根据本申请实施例提供的非水电解液，将具有特定还原电位的含硫添加剂作为第一添加剂加入到非水电解液中，由于其具有较好的还原电位，能够在首次充电过程中在负极与非水电解液接触的界面处形成含有烷基亚硫酸锂(ROSO₂Li)的界面膜。该界面膜虽然可以抑制后续非水有机溶剂在界面的不断消耗，但是会造成界面阻抗增加。而含有不饱和三价磷结构的亚磷酸酯类添加剂在锂离子电池中不稳定，在羟基醇的作用下会在锂离子首次由正极向负极移动的过程中与上述第一添加剂共同在负极界面形成无机成分含量较高的界面膜，两者协同作用有利于提升锂离子的传输效率，降低了界面阻抗。同时硫氧键结构能够在一定程度上提高电解液的电导率，改善锂离子电池的动力学性能。另外由于第二添加剂的不饱和三价磷结构的强还原性，有利于避免第一添加剂在电解液中被PF₅攻击而导致的分解，保留有效成分，从而有利于改善高温存储。发明人经过大量研究发现，在采用环状碳酸酯作为非水有机溶剂，甲醇和乙二醇的总醇量在500ppm及以下以及25℃下的电导率为7mS/cm～10.5mS/cm的非水电解液体系中，当满足条件：0.05％≤A≤1.8％，0.01％≤B≤0.2％，0.15≤A/(B*10)≤10.5时，锂离子电池具有最佳的高温电化学性能，但不满足该条件时，会造成电解液品质的劣化，同时造成有效锂盐成分的分解和界面阻抗的增加。According to the non-aqueous electrolyte provided in the embodiments of the present application, a sulfur-containing additive with a specific reduction potential is added as the first additive to the non-aqueous electrolyte. Since it has a good reduction potential, it can be used in the negative electrode during the first charging process. An interfacial film containing lithium alkyl sulfite (ROSO ₂ Li) is formed at the interface in contact with the non-aqueous electrolyte. Although this interface film can inhibit the subsequent continuous consumption of non-aqueous organic solvents at the interface, it will cause an increase in interface impedance. Phosphite additives containing unsaturated trivalent phosphorus structures are unstable in lithium-ion batteries. Under the action of hydroxyl alcohol, they will form with the above-mentioned first additive at the negative electrode interface during the first movement of lithium ions from the positive electrode to the negative electrode. An interface film with a high content of inorganic components is formed, and the synergistic effect of the two is beneficial to improving the transmission efficiency of lithium ions and reducing the interface impedance. At the same time, the sulfur-oxygen bond structure can increase the conductivity of the electrolyte to a certain extent and improve the dynamic performance of lithium-ion batteries. In addition, due to the strong reducibility of the unsaturated trivalent phosphorus structure of the second additive, it is helpful to avoid the decomposition of the first additive caused by being attacked by PF ₅ in the electrolyte, retaining the active ingredients, thereby helping to improve high-temperature storage. After extensive research, the inventor found that when using cyclic carbonate as a non-aqueous organic solvent, the total alcohol content of methanol and ethylene glycol is 500 ppm and below and the conductivity at 25°C is 7 mS/cm ~ 10.5 mS/cm. In the water electrolyte system, when the conditions are met: 0.05%≤A≤1.8%, 0.01%≤B≤0.2%, 0.15≤A/(B*10)≤10.5, the lithium-ion battery has the best high-temperature electrochemical performance , but when this condition is not met, the quality of the electrolyte will deteriorate, and the effective lithium salt components will decompose and the interface impedance will increase.

具体实施方式Detailed ways

为了使本申请所解决的技术问题、技术方案及有益效果更加清楚明白，以下结合实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。In order to make the technical problems, technical solutions and beneficial effects solved by this application clearer, this application will be further described in detail below in conjunction with examples. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

本申请实施例提供了一种非水电解液，包括非水有机溶剂、电解质盐和添加剂，所述非水有机溶剂包括环状碳酸酯，所述环状碳酸酯在所述非水有机溶剂中的质量百分含量为10～40％；The embodiments of the present application provide a non-aqueous electrolyte, including a non-aqueous organic solvent, an electrolyte salt and an additive. The non-aqueous organic solvent includes a cyclic carbonate, and the cyclic carbonate is in the non-aqueous organic solvent. The mass percentage is 10~40%;

所述非水电解液的电导率影响电解质离子在非水电解液中的传输效率，当所述非水电解液的电导率过低时，会影响到电解质离子在负极中的嵌入和脱出，进而导致电池的阻抗提升，同时非水电解液的电导率也会对首次充电放电条件下负极表面界面膜的致密程度产生一定的影响。The conductivity of the non-aqueous electrolyte affects the transmission efficiency of electrolyte ions in the non-aqueous electrolyte. When the conductivity of the non-aqueous electrolyte is too low, it will affect the insertion and extraction of electrolyte ions in the negative electrode, thereby affecting the insertion and extraction of electrolyte ions in the negative electrode. This leads to an increase in the impedance of the battery, and at the same time, the conductivity of the non-aqueous electrolyte will also have a certain impact on the density of the interface film on the negative electrode surface under the first charge and discharge conditions.

所述非水电解液中，加入了含硫添加剂作为第一添加剂和亚磷酸酯类添加剂作为第二添加剂，第一添加剂和第二添加剂用于形成电池的负极表面界面膜，而非水电解液中环状碳酸酯、甲醇和乙二醇的存在会影响该界面膜的形成和质量；发明人经过大量研究发现，在采用环状碳酸酯作为非水有机溶剂，甲醇和乙二醇的总醇量在500ppm及以下以及25℃下的电导率为7mS/cm～10.5mS/cm的非水电解液体系中，当满足条件：0.05％≤A≤1.8％，0.01％≤B≤0.2％，0.15≤A/(B*10)≤10.5时，锂离子电池具有最佳的高温电化学性能，但不满足该条件时，会造成电解液品质的劣化，同时造成有效锂盐成分的分解和界面阻抗的增加。In the non-aqueous electrolyte, sulfur-containing additives are added as the first additive and phosphite additives are added as the second additive. The first additive and the second additive are used to form the negative electrode surface interface film of the battery, and the non-aqueous electrolyte is The presence of cyclic carbonate, methanol and ethylene glycol will affect the formation and quality of the interface film; the inventor found through extensive research that when using cyclic carbonate as a non-aqueous organic solvent, the total alcohol content of methanol and ethylene glycol In a non-aqueous electrolyte system with an amount of 500 ppm and below and a conductivity of 7 mS/cm ~ 10.5 mS/cm at 25°C, when the conditions are met: 0.05% ≤ A ≤ 1.8%, 0.01% ≤ B ≤ 0.2%, 0.15 When ≤A/(B*10)≤10.5, the lithium-ion battery has the best high-temperature electrochemical performance. However, if this condition is not met, the quality of the electrolyte will be deteriorated, and the effective lithium salt components will be decomposed and interface impedance will be caused. increase.

在一些实施例中，所述非水电解液中第一添加剂的质量百分含量A为0.05％～1.8％。In some embodiments, the mass percentage A of the first additive in the non-aqueous electrolyte is 0.05% to 1.8%.

在具体的实施例中，所述非水电解液中第一添加剂的质量百分含量A可以为0.05％、0.08％、0.1％、0.12％、0.15％、0.3％、0.5％、0.8％、0.9％、1.0％、1.2％、1.4％、1.7％或1.8％。In specific embodiments, the mass percentage A of the first additive in the non-aqueous electrolyte can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.3%, 0.5%, 0.8%, 0.9 %, 1.0%, 1.2%, 1.4%, 1.7% or 1.8%.

在一些实施例中，所述第一添加剂的还原电位为0.95～1.35V(vs.Li/Li+)，且非水电解液中第一添加剂的质量百分含量A为0.2％～1.5％。In some embodiments, the reduction potential of the first additive is 0.95-1.35V (vs. Li/Li+), and the mass percentage A of the first additive in the non-aqueous electrolyte is 0.2%-1.5%.

所述第一添加剂处于上述还原电位下，能在首次充电过程中在负极与非水电解液接触的界面处形成含有烷基亚硫酸锂(ROSO₂Li)的界面膜，当第一添加剂的含量过低时，则对于负极材料与非水电解液的阻隔效果不足，易导致非水电解液的持续分解；当第二添加剂的含量过高时，则界面膜中烷基亚硫酸锂(ROSO₂Li)的含量过高，导致负极界面阻抗的增加，影响电池容量发挥。The first additive is at the above-mentioned reduction potential and can form an interface film containing alkyl lithium sulfite (ROSO ₂ Li) at the interface between the negative electrode and the non-aqueous electrolyte during the first charging process. When the content of the first additive When the content of the second additive is too high, the barrier effect between the negative electrode material and the non-aqueous electrolyte is insufficient, which may easily lead to the continued decomposition of the non-aqueous electrolyte; when the content of the second additive is too high, the lithium alkyl sulfite (ROSO ₂ The content of Li) is too high, which leads to an increase in the interface resistance of the negative electrode and affects the battery capacity.

在一些实施例中，所述非水电解液中第二添加剂的质量百分含量B为0.01％～0.2％。In some embodiments, the mass percentage B of the second additive in the non-aqueous electrolyte is 0.01% to 0.2%.

在具体的实施例中，所述非水电解液中第二添加剂的质量百分含量B可以为0.01％、0.02％、0.05％、0.08％、0.1％、0.11％、0.12％、0.13％、0.14％、0.15％、0.17％、0.18％、0.19％或0.2％。 In specific embodiments, the mass percentage B of the second additive in the non-aqueous electrolyte can be 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14 %, 0.15%, 0.17%, 0.18%, 0.19% or 0.2%.

所述第二添加剂中含有不饱和三价磷结构，在非水电解液中不稳定，在羟基醇的作用下会在锂离子首次由正极向负极移动的过程中与上述第一添加剂共同在负极界面形成无机成分含量较高的界面膜，以弥补单一含硫添加剂分解得到的界面膜的离子电导率不足的问题。当所述第二添加剂的含量过低时，难以降低负极的界面膜的阻抗；当所述第二添加剂的含量过高时，会导致负极表面界面膜的厚度过高，同样不利于降低界面膜的阻抗。The second additive contains an unsaturated trivalent phosphorus structure, which is unstable in the non-aqueous electrolyte. Under the action of hydroxyl alcohol, it will work with the above-mentioned first additive in the negative electrode during the first movement of lithium ions from the positive electrode to the negative electrode. The interface forms an interface film with a high content of inorganic components to make up for the insufficient ionic conductivity of the interface film obtained by decomposing a single sulfur-containing additive. When the content of the second additive is too low, it is difficult to reduce the impedance of the interface film of the negative electrode; when the content of the second additive is too high, the thickness of the interface film on the surface of the negative electrode will be too high, which is also not conducive to reducing the interface film. of impedance.

将非水电解液中第一添加剂的含量A和第二添加剂的含量B相关联，能够一定程度上综合第一添加剂和第二添加剂对于负极表面界面膜的成膜影响，得到一种高温下稳定且阻抗较低的界面膜，利于提高电池的高温循环性能和避免电池高温膨胀。Correlating the content A of the first additive and the content B of the second additive in the non-aqueous electrolyte can, to a certain extent, combine the effects of the first additive and the second additive on the formation of the interface film on the negative electrode surface to obtain a stable solution at high temperatures. And the interface film with lower impedance is conducive to improving the high-temperature cycle performance of the battery and avoiding high-temperature expansion of the battery.

在一些实施例中，所述非水电解液在25℃下的电导率C为7mS/cm～10.5mS/cm。In some embodiments, the conductivity C of the non-aqueous electrolyte solution at 25° C. is 7 mS/cm˜10.5 mS/cm.

在具体的实施例中，所述非水电解液在25℃下的电导率C为7mS/cm、7.2mS/cm、7.6mS/cm、7.9mS/cm、8.1mS/cm、8.3mS/cm、8.5mS/cm、8.8mS/cm、9.2mS/cm、9.4mS/cm、9.7mS/cm、9.9mS/cm、10.2mS/cm或10.5mS/cm。In specific embodiments, the conductivity C of the non-aqueous electrolyte at 25°C is 7mS/cm, 7.2mS/cm, 7.6mS/cm, 7.9mS/cm, 8.1mS/cm, 8.3mS/cm , 8.5mS/cm, 8.8mS/cm, 9.2mS/cm, 9.4mS/cm, 9.7mS/cm, 9.9mS/cm, 10.2mS/cm or 10.5mS/cm.

在一些实施例中，所述非水有机溶剂中环状碳酸酯的质量百分含量为20％～90％。In some embodiments, the mass percentage of cyclic carbonate in the non-aqueous organic solvent is 20% to 90%.

在具体的实施例中，所述非水有机溶剂中环状碳酸酯的质量百分含量可以为20％、24％、25％、28％、30％、32％、36％、39％、41％、43％、46％、48％、52％、54％、58％、60％、65％、68％、70％、73％、79％、81％、85％或90％。In specific embodiments, the mass percentage of cyclic carbonate in the non-aqueous organic solvent can be 20%, 24%, 25%, 28%, 30%, 32%, 36%, 39%, 41 %, 43%, 46%, 48%, 52%, 54%, 58%, 60%, 65%, 68%, 70%, 73%, 79%, 81%, 85% or 90%.

通过设定该范围，可避免由于非水电解液的介电常数降低而导致电导率降低，易于使非水电解质电池的大电流放电特性、相对于负极的稳定性、循环特性达到良好的范围。另外，上限通常质量比为90％以下，在一些实施例中质量比为85％以下，在一些实施例中质量比为80％以下。通过设定该范围，可提高非水电解液的氧化/还原耐性，从而有助于提高高温保存时的稳定性。By setting this range, it is possible to avoid a decrease in conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte, and it is easy to achieve a good range for the large current discharge characteristics, stability relative to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery. In addition, the upper limit is usually 90% or less by mass, in some embodiments it is 85% or less, and in some embodiments it is 80% or less. By setting this range, the oxidation/reduction resistance of the non-aqueous electrolyte solution can be improved, thereby helping to improve the stability during high-temperature storage.

需要说明的是，以上仅是本申请一些实施例提供的化合物，并不代表对于本申请的限制。 It should be noted that the above are only compounds provided in some examples of the present application and do not represent limitations to the present application.

在一些实施例中，所述电解质盐选自LiPF₆、LiBOB、LiDFOB、LiDFOP、LiPO₂F₂、LiBF₄、LiSbF₆、LiAsF₆、LiN(SO₂CF₃)₂、LiN(SO₂C₂F₅)₂、LiC(SO₂CF₃)₃、LiN(SO₂F)₂、LiClO₄、LiAlCl₄、LiCF₃SO₃、Li₂B₁₀Cl₁₀、低级脂肪族羧酸锂盐中的至少一种。具体的，电解质盐可以为LiBF₄、LiClO₄、LiAlF₄、LiSbF₆、LiTaF₆、LiWF₇等无机电解质盐；LiPF₆等氟磷酸电解质盐类；LiWOF₅等钨酸电解质盐类；HCO₂Li、CH₃CO₂Li、CH₂FCO₂Li、CHF₂CO₂Li、CF₃CO₂Li、CF₃CH₂CO₂Li、CF₃CF₂CO₂Li、CF₃CF₂CF₂CO₂Li、CF₃CF₂CF₂CF₂CO₂Li等羧酸电解质盐类；CH₃SO₃Li等磺酸电解质盐类；LiN(FCO₂)₂、LiN(FCO)(FSO₂)、LiN(FSO₂)₂、LiN(FSO₂)(CF₃SO₂)、LiN(CF₃SO₂)₂、LiN(C₂F₅SO₂)₂、环状1,2-全氟乙二磺酰亚胺锂、环状1,3-全氟丙二磺酰亚胺锂、LiN(CF₃SO₂)(C₄F₉SO₂)等酰亚胺电解质盐类；LiC(FSO₂)₃、LiC(CF₃SO₂)₃、LiC(C₂F₅SO₂)₃等甲基电解质盐类；以及LiPF₄(CF₃)₂、LiPF₄(C₂F₅)₂、LiPF₄(CF₃SO₂)₂、LiPF₄(C₂F₅SO₂)₂、LiBF₃CF₃、LiBF₃C₂F₅、LiBF₃C₃F₇、LiBF₂(CF₃)₂、LiBF₂(C₂F₅)₂、LiBF₂(CF₃SO₂)₂、LiBF₂(C₂F₅SO₂)₂等含氟有机电解质盐类等。In some embodiments, the electrolyte salt is selected from LiPF ₆ , LiBOB, LiDFOB, LiDFOP, LiPO ₂ F ₂ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ At least one of F ₅ ) ₂ , LiC(SO ₂ CF ₃ ) ₃ , LiN(SO ₂ F) ₂ , LiClO ₄ , LiAlCl ₄ , LiCF ₃ SO ₃ , Li ₂ B ₁₀ Cl ₁₀ , and lower aliphatic carboxylic acid lithium salts. A sort of. Specifically, the electrolyte salt can be inorganic electrolyte salts such as LiBF ₄ , LiClO ₄ , LiAlF ₄ , LiSbF ₆ , LiTaF ₆ , and LiWF ₇ ; fluorophosphoric acid electrolyte salts such as LiPF ₆ ; tungstic acid electrolyte salts such as LiWOF ₅ ; HCO ₂ Li , CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF _{3 CF 2 CO 2 Li, CF 3} _CF ₂ _CF ₂ _CO ₂ Li , CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li and other carboxylic acid electrolyte salts; CH ₃ SO ₃ Li and other sulfonic acid electrolyte salts; LiN(FCO ₂ ) ₂ , LiN(FCO)(FSO ₂ ), LiN(FSO ₂ ) ₂ , LiN(FSO ₂ )(CF ₃ SO ₂ ), LiN(CF ₃ SO ₂ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ , cyclic 1,2-perfluoroethanedisulfonimide Lithium, cyclic lithium 1,3-perfluoropropanedisulfonimide, LiN(CF ₃ SO ₂ )(C ₄ F ₉ SO ₂ ) and other imide electrolyte salts; LiC(FSO ₂ ) ₃ , LiC( Methyl electrolyte salts such as CF ₃ SO ₂ ) ₃ and LiC(C ₂ F ₅ SO ₂ ) ₃ ; and LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiBF ₃ C ₃ F ₇ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C ₂ F ₅ ) _2. LiBF ₂ (CF ₃ SO ₂ ) ₂ , LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ and other fluorine-containing organic electrolyte salts, etc.

在一些实施例中，所述电解质盐选自LiPF₆、LiPO₂F₂、LiBF₄、LiClO₄、LiCF₃SO₃、LiN(SO₂CF₃)₂和LiN(SO₂F)₂中的一种或多种。In some embodiments, the electrolyte salt is selected from one of LiPF ₆ , LiPO ₂ F ₂ , LiBF ₄ , LiClO ₄ , LiCF ₃ SO ₃ , LiN(SO ₂ CF ₃ ) ₂ and LiN(SO ₂ F) ₂ Kind or variety.

在一些实施例中，所述非水电解液中电解质盐的浓度为0.5-3.5mol/L。In some embodiments, the concentration of the electrolyte salt in the non-aqueous electrolyte solution is 0.5-3.5 mol/L.

在一些实施例中，所述电解质盐在电解液中的总浓度可以为0.5mol/L～2.0mol/L、0.5mol/L～0.6mol/L、0.6mol/L～0.7mol/L、0.7mol/L～0.8mol/L、0.8mol/L～0.9mol/L、0.9mol/L～1.0mol/L、1.0mol/L～1.1mol/L、1.1mol/L～1.2mol/L、1.2mol/L～1.3mol/L、1.3mol/L～1.4mol/L、1.4mol/L～1.5mol/L、1.5mol/L～1.6mol/L、1.6mol/L～1.7mol/L、1.7mol/L～1.8mol/L、1.8mol/L～1.9mol/L、或1.9mol/L～2.0mol/L，在一些实施例中可以为0.6mol/L～1.8mol/L、0.7mol/L～1.7mol/L、或0.8mol/L～1.5mol/L。In some embodiments, the total concentration of the electrolyte salt in the electrolyte solution may be 0.5 mol/L ~ 2.0 mol/L, 0.5 mol/L ~ 0.6 mol/L, 0.6 mol/L ~ 0.7 mol/L, 0.7 mol/L～0.8mol/L, 0.8mol/L～0.9mol/L, 0.9mol/L～1.0mol/L, 1.0mol/L～1.1mol/L, 1.1mol/L～1.2mol/L, 1.2 mol/L～1.3mol/L, 1.3mol/L～1.4mol/L, 1.4mol/L～1.5mol/L, 1.5mol/L～1.6mol/L, 1.6mol/L～1.7mol/L, 1.7 mol/L～1.8mol/L, 1.8mol/L～1.9mol/L, or 1.9mol/L～2.0mol/L, in some embodiments it can be 0.6mol/L～1.8mol/L, 0.7mol/L L～1.7mol/L, or 0.8mol/L～1.5mol/L.

在一些实施例中，所述非水电解液中还包括第三添加剂，所述第三添加剂包括磺酸内酯类化合物、环状碳酸酯类化合物、二氟磷酸锂和腈类化合物中的至少一种；In some embodiments, the non-aqueous electrolyte further includes a third additive, and the third additive includes at least one of sultone compounds, cyclic carbonate compounds, lithium difluorophosphate, and nitrile compounds. A sort of;

在一些实施例中，所述磺酸内酯类化合物选自甲基二磺酸亚甲酯、1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯或1,3-丙烯磺酸内酯中的至少一种； In some embodiments, the sultone compound is selected from methylene methyldisulfonate, 1,3-propane sultone, 1,4-butane sultone or 1,3- At least one kind of propylene sultone;

所述环状碳酸酯类化合物选自碳酸乙烯亚乙酯、氟代碳酸乙烯酯或式Ⅲ所示化合物中的至少一种，
The cyclic carbonate compound is selected from at least one of ethylene ethylene carbonate, fluoroethylene carbonate or the compound represented by formula III,

所述式Ⅲ中，R₂₁、R₂₂、R₂₃、R₂₄、R₂₅、R₂₆各自独立地选自氢原子、卤素原子、C1-C5基团中的一种；In the formula III, R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , and R ₂₆ are each independently selected from one of hydrogen atoms, halogen atoms, and C1-C5 groups;

在另一些实施例中，所述第三添加剂还可包括其它能改善电池性能的添加剂：例如，提升电池安全性能的添加剂，具体如氟代磷酸酯、环磷腈等阻燃添加剂，或叔戊基苯、叔丁基苯等防过充添加剂。In other embodiments, the third additive may also include other additives that can improve battery performance: for example, additives that improve battery safety performance, specifically flame retardant additives such as fluorinated phosphates, cyclophosphazene, or tert-pentyl phosphate. Benzene, tert-butylbenzene and other anti-overcharge additives.

在一些实施例中，以所述非水电解液的总质量为100％计，所述第三添加剂的添加量为0.01％～30％。In some embodiments, based on the total mass of the non-aqueous electrolyte being 100%, the amount of the third additive added is 0.01% to 30%.

需要说明的是，除非特殊说明，一般情况下，所述第三添加剂中任意一种可选物质在非水电解液中的添加量为10％以下(例如0.05％～10％)，在一些实施例中，添加量为0.1-5％，在一些实施例中，添加量为0.1％～2％。具体的，所述第三添加剂中任意一种可选物质的添加量可以为0.05％、0.08％、0.1％、0.5％、0.8％、1％、1.2％、1.5％、1.8％、2％、2.2％、2.5％、2.8％、3％、3.2％、3.5％、3.8％、4％、4.5％、5％、5.5％、6％、6.5％、7％、7.5％、7.8％、8％、8.5％、9％、9.5％、10％。It should be noted that, unless otherwise specified, in general, the amount of any optional substance in the third additive added to the non-aqueous electrolyte is less than 10% (for example, 0.05% to 10%). In some implementations, In some examples, the added amount is 0.1-5%, and in some embodiments, the added amount is 0.1%-2%. Specifically, the amount of any optional substance in the third additive can be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8% , 8.5%, 9%, 9.5%, 10%.

在一些实施例中，当第三添加剂选自氟代碳酸乙烯酯时，以所述非水电解液的总质量为100％计，所述氟代碳酸乙烯酯的添加量为0.05％～30％。In some embodiments, when the third additive is selected from fluorinated ethylene carbonate, the added amount of the fluorinated ethylene carbonate is 0.05% to 30% based on the total mass of the non-aqueous electrolyte being 100%. .

在一些实施例中，所述环状碳酸酯选自碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(GBL)、碳酸亚丁酯(BC)中的一种或多种。 In some embodiments, the cyclic carbonate is selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), and butylene carbonate (BC). .

在一些实施例中，所述非水有机溶剂还包括醚类溶剂、腈类溶剂、链状碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。In some embodiments, the non-aqueous organic solvent further includes one or more of ether solvents, nitrile solvents, chain carbonate solvents and carboxylate solvents.

在一些实施例中，醚类溶剂包括环状醚或链状醚，在一些实施例中为碳原子数3～10的链状醚及碳原子数3～6的环状醚，环状醚具体可以但不限于是1,3-二氧戊烷(DOL)、1,4-二氧惡烷(DX)、冠醚、四氢呋喃(THF)、2-甲基四氢呋喃(2-CH₃-THF)，2-三氟甲基四氢呋喃(2-CF₃-THF)中的一种或多种；所述链状醚具体可以但不限于是二甲氧基甲烷、二乙氧基甲烷、乙氧基甲氧基甲烷、乙二醇二正丙基醚、乙二醇二正丁基醚、二乙二醇二甲基醚。由于链状醚与锂离子的非水有机溶剂化能力高、可提高离子解离性，因此特别优选粘性低、可赋予高离子电导率的二甲氧基甲烷、二乙氧基甲烷、乙氧基甲氧基甲烷。醚类化合物可以单独使用一种，也可以以任意的组合及比率组合使用两种以上。醚类化合物的添加量没有特殊限制，在不显著破坏本申请实施例高压实锂离子电池效果的范围内是任意的，在非水有机溶剂体积比为100％中通常体积比为1％以上、在一些实施例中体积比为2％以上、在一些实施例中体积比为3％以上，另外，通常体积比为30％以下、在一些实施例中体积比为25％以下、在一些实施例中体积比为20％以下。在将两种以上醚类化合物组合使用的情况下，使醚类化合物的总量满足上述范围即可。醚类化合物的添加量在上述的范围内时，易于确保由链状醚的锂离子离解度的提高和粘度降低所带来的离子电导率的改善效果。另外，负极活性材料为碳素材料的情况下，可抑制因链状醚与锂离子共同发生共嵌入的现象，因此能够使输入输出特性、充放电速率特性达到适当的范围。In some embodiments, ether solvents include cyclic ethers or chain ethers. In some embodiments, they are chain ethers with 3 to 10 carbon atoms and cyclic ethers with 3 to 6 carbon atoms. The cyclic ethers are specifically It can be but is not limited to 1,3-dioxopentane (DOL), 1,4-dioxane (DX), crown ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH ₃ -THF) , one or more of 2-trifluoromethyltetrahydrofuran (2-CF ₃ -THF); the chain ether can be, but is not limited to, dimethoxymethane, diethoxymethane, ethoxy Methoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether. Since chain ethers have high non-aqueous organic solvation capacity with lithium ions and can improve ion dissociation, dimethoxymethane, diethoxymethane, and ethoxy are particularly preferred because they have low viscosity and can impart high ionic conductivity. Methoxymethane. One type of ether compound may be used alone, or two or more types of ether compounds may be used in any combination and ratio. There is no special limit to the amount of ether compound added, and it is arbitrary within the range that does not significantly damage the effect of the high-pressure lithium-ion battery in the embodiment of the present application. When the volume ratio of the non-aqueous organic solvent is 100%, the volume ratio is usually more than 1%. , in some embodiments the volume ratio is above 2%, in some embodiments the volume ratio is above 3%, in addition, usually the volume ratio is below 30%, in some embodiments the volume ratio is below 25%, in some implementations In the example, the volume ratio is 20% or less. When two or more ether compounds are used in combination, the total amount of the ether compounds may satisfy the above range. When the amount of the ether compound added is within the above range, it is easy to ensure the effect of improving the ion conductivity by increasing the degree of lithium ion dissociation and reducing the viscosity of the chain ether. In addition, when the negative electrode active material is a carbon material, the phenomenon of co-intercalation of chain ether and lithium ions can be suppressed, so that the input-output characteristics and charge-discharge rate characteristics can be achieved within an appropriate range.

在一些实施例中，腈类溶剂具体可以但不限于是乙腈、戊二腈、丙二腈中的一种或多种。In some embodiments, the nitrile solvent may be, but is not limited to, one or more of acetonitrile, glutaronitrile, and malononitrile.

在一些实施例中，链状碳酸酯具体可以但不限于是碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)中的一种或多种。链状碳酸酯的含量没有特殊限定，相对于非水电解液的非水有机溶剂总量，通常为体积比为15％以上、在一些实施例中体积比为20％以上、在一些实施例中体积比为25％以上。另外，通常体积比为80％以下。通过使链状碳酸酯的含量在上述范围，容易使非水电解液的粘度达到适当范围，抑制离子电导率的降低，进而有助于使非水电解质电池的输出特性达到良好的范围。在组合使用两种以上链状碳酸酯的情况下，使链状碳酸酯的总量满足上述范围即可。 In some embodiments, the chain carbonate may be, but is not limited to, one of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and dipropyl carbonate (DPC). Kind or variety. The content of the chain carbonate is not particularly limited. The volume ratio relative to the total amount of non-aqueous organic solvent in the non-aqueous electrolyte is usually 15% or more. In some embodiments, the volume ratio is 20% or more. In some embodiments, the content is 20% or more. The volume ratio is above 25%. In addition, the volume ratio is usually 80% or less. By setting the content of the chain carbonate within the above range, the viscosity of the non-aqueous electrolyte solution can be easily brought into an appropriate range, thereby suppressing a decrease in ion conductivity, thereby contributing to bringing the output characteristics of the non-aqueous electrolyte battery into a favorable range. When two or more linear carbonates are used in combination, the total amount of the linear carbonates may satisfy the above range.

在一些实施例中，还可使用具有氟原子的链状碳酸酯类(以下简称为“氟化链状碳酸酯”)。氟化链状碳酸酯所具有的氟原子的个数只要为1以上则没有特殊限制，但通常为6以下、在一些实施例中为4以下。氟化链状碳酸酯具有多个氟原子的情况下，这些氟原子相互可以键合于同一个碳上，也可以键合于不同的碳上。作为氟化链状碳酸酯，可列举，氟化碳酸二甲酯衍生物、氟化碳酸甲乙酯衍生物、氟化碳酸二乙酯衍生物等。In some embodiments, chain carbonates having fluorine atoms (hereinafter referred to as "fluorinated chain carbonates") may also be used. The number of fluorine atoms in the fluorinated linear carbonate is not particularly limited as long as it is 1 or more, but it is usually 6 or less, and in some embodiments, it is 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, these fluorine atoms may be bonded to the same carbon or to different carbons. Examples of the fluorinated chain carbonate include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, and fluorinated diethyl carbonate derivatives.

羧酸酯类溶剂包括环状羧酸酯和/或链状碳酸酯。作为环状羧酸酯的例子，可以列举如：γ-丁内酯、γ-戊内酯、δ-戊内酯中的一种或多种。作为链状碳酸酯的例子，可以列举如：乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(EP)、乙酸丁酯、丙酸丙酯(PP)、丙酸丁酯中的一种或多种。Carboxylic acid ester solvents include cyclic carboxylic acid esters and/or chain carbonic acid esters. Examples of cyclic carboxylic acid esters include one or more of γ-butyrolactone, γ-valerolactone, and δ-valerolactone. Examples of chain carbonates include methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate. of one or more.

在一些实施例中，砜类溶剂包括环状砜和链状砜，在为环状砜的实施例中，通常为碳原子数3～6的化合物、在一些实施例中为碳原子数3～5的化合物，在为链状砜的实施例中，通常为碳原子数2～6的化合物、在一些实施例中为碳原子数2～5的化合物。砜类溶剂的添加量没有特殊限制，在不显著破坏本申请实施例锂离子电池效果的范围内是任意的，相对于非水电解液的非水有机溶剂总量，通常体积比为0.3％以上、在一些实施例中体积比为0.5％以上、在一些实施例中体积比为1％以上，另外，通常体积比为40％以下、在一些实施例中体积比为35％以下、在一些实施例中体积比为30％以下。在组合使用两种以上砜类溶剂的情况下，使砜类溶剂的总量满足上述范围即可。砜类溶剂的添加量在上述范围内时，倾向于获得高温保存稳定性优异的电解液。In some embodiments, the sulfone solvent includes cyclic sulfone and chain sulfone. In the embodiment of cyclic sulfone, it is usually a compound with 3 to 6 carbon atoms. In some embodiments, it is a compound with 3 to 6 carbon atoms. In the embodiment where the compound of 5 is a chain sulfone, it is usually a compound having 2 to 6 carbon atoms, and in some embodiments, it is a compound having 2 to 5 carbon atoms. There is no special limit to the amount of sulfone solvent added. It is arbitrary within the range that does not significantly damage the effect of the lithium-ion battery in the embodiment of the present application. The volume ratio relative to the total amount of non-aqueous organic solvent in the non-aqueous electrolyte is usually 0.3% or more. , in some embodiments the volume ratio is above 0.5%, in some embodiments the volume ratio is above 1%, in addition, usually the volume ratio is below 40%, in some embodiments the volume ratio is below 35%, in some embodiments In the example, the volume ratio is 30% or less. When two or more sulfone solvents are used in combination, the total amount of the sulfone solvents may satisfy the above range. When the added amount of the sulfone solvent is within the above range, an electrolyte solution excellent in high-temperature storage stability tends to be obtained.

在一些实施例中，所述非水有机溶剂为环状碳酸酯和链状碳酸酯的混合物。In some embodiments, the non-aqueous organic solvent is a mixture of cyclic carbonates and chain carbonates.

本申请的另一实施例提供了一种二次电池，包括正极、负极以及如上所述的非水电解液。Another embodiment of the present application provides a secondary battery including a positive electrode, a negative electrode and the non-aqueous electrolyte as described above.

在一些实施例中，所述正极包括正极材料层和正极集流体，所述正极材料层形成于所述正极集流体的表面。In some embodiments, the positive electrode includes a positive electrode material layer and a positive electrode current collector, and the positive electrode material layer is formed on the surface of the positive electrode current collector.

所述正极集流体选自可传导电子的金属材料，在一些实施例中，所述正极集流体包括Al、Ni、锡、铜、不锈钢的一种或多种，在一些实施例中，所述正极集流体选自铝箔。The positive current collector is selected from metal materials that can conduct electrons. In some embodiments, the positive current collector includes one or more of Al, Ni, tin, copper, and stainless steel. In some embodiments, the positive current collector The positive current collector is selected from aluminum foil.

所述正极材料层包括正极活性材料、正极粘结剂和正极导电剂。The positive electrode material layer includes a positive electrode active material, a positive electrode binder and a positive electrode conductive agent.

所述正极粘结剂包括聚偏氟乙烯、偏氟乙烯的共聚物、聚四氟乙烯、偏氟乙烯-六氟丙烯的共聚物、四氟乙烯-六氟丙烯的共聚物、四氟乙烯-全氟烷基乙烯基醚的共聚物、乙烯-四氟乙烯的共聚物、偏氟乙烯-四氟乙烯的共聚物、偏氟乙烯-三氟乙烯的共聚物、偏氟乙烯-三氯乙烯的共聚物、偏氟乙烯-氟代乙烯的共聚物、偏氟乙烯-六氟丙烯-四氟乙烯的共聚物、热塑性聚酰亚胺、聚乙烯及聚丙烯等热塑性树脂；丙烯酸类树脂；羟甲基纤维素钠；以及苯乙烯丁二烯橡胶中的一种或多种。The positive electrode binder includes polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, tetrafluoroethylene- Perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride Copolymer of vinylidene-trifluoroethylene, copolymer of vinylidene fluoride-trichloroethylene, copolymer of vinylidene fluoride-vinyl fluoride, copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide Thermoplastic resins such as amine, polyethylene and polypropylene; acrylic resin; sodium carboxymethylcellulose; and one or more of styrene butadiene rubber.

所述正极导电剂包括导电炭黑、导电碳球、导电石墨、导电碳纤维、碳纳米管、石墨烯或还原氧化石墨烯中的一种或多种。The positive conductive agent includes one or more of conductive carbon black, conductive carbon balls, conductive graphite, conductive carbon fiber, carbon nanotubes, graphene or reduced graphene oxide.

所述正极活性材料的种类没有特别限制，可以根据实际需求进行选择，只要是能够可逆地嵌入/脱嵌锂离子的正极活性材料或转换型正极材料即可。The type of the cathode active material is not particularly limited and can be selected according to actual needs, as long as it is a cathode active material or a conversion cathode material that can reversibly intercalate/deintercalate lithium ions.

在一些实施例中，所述电池为锂离子电池，其正极活性材料可选自LiFe_1-x’M’_x’PO₄、LiMn_2-y’M_y’O₄和LiNi_xCo_yMn_zM_1-x-y-zO₂中的一种或多种，其中，M’选自Mn、Mg、Co、Ni、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V或Ti中的一种或多种，M选自Fe、Co、Ni、Mn、Mg、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V或Ti中的一种或多种，且0≤x’＜1，0≤y’≤1，0≤y≤1，0≤x≤1，0≤z≤1，x+y+z≤1，所述正极活性材料还可以选自硫化物、硒化物、卤化物中的一种或几种。在一些实施例中，所述正极活性材料可选自LiCoO₂、LiFePO₄、LiFe_0.8Mn_0.2PO₄、LiNi_0.5Co_0.2Mn_0.3O₂、LiNi_0.6Co_0.2Mn_0.2O₂、LiNi_0.8Co_0.1Mn_0.1O₂、LiNi_0.5Co_0.2Mn_0.2Al_0.1O₂、LiMn₂O₄、LiNi_0.5Co_0.2Al_0.3O₂中的一种或多种。In some embodiments, the battery is a lithium-ion battery, and its positive active material can be selected from LiFe _1-x' M'_x' PO ₄ , LiMn _2-y' My _y' O ₄ and _LiNix Co _y Mn _z One or more of M _1-xyz O ₂ , wherein M' is selected from one of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti One or more kinds, M is selected from one or more kinds of Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, and 0≤x'<1,0≤y'≤1, 0≤y≤1, 0≤x≤1, 0≤z≤1, x+y+z≤1, the positive active material can also be selected from sulfide and selenide , one or more of the halides. In some embodiments, the cathode active material may be selected from LiCoO ₂ , LiFePO ₄ , LiFe _0.8 Mn _0.2 PO ₄ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , LiNi _0.6 Co _0.2 Mn _0.2 O ₂ , LiNi _0.8 Co _0.1 Mn One or more of _0.1 O ₂ , LiNi _0.5 Co _0.2 Mn _0.2 Al _0.1 O ₂ , LiMn ₂ O ₄ , LiNi _0.5 Co _0.2 Al _0.3 O ₂ .

在一些实施例中，所述负极包括负极材料层和负极集流体，所述负极材料层形成于所述负极集流体的表面。In some embodiments, the negative electrode includes a negative electrode material layer and a negative electrode current collector, and the negative electrode material layer is formed on the surface of the negative electrode current collector.

所述负极集流体选自可传导电子的金属材料，在一些实施例中，所述负极集流体包括Al、Ni、锡、铜、不锈钢的一种或多种，在一些实施例中，所述负极集流体选自铜箔。The negative electrode current collector is selected from metal materials that can conduct electrons. In some embodiments, the negative electrode current collector includes one or more of Al, Ni, tin, copper, and stainless steel. In some embodiments, the negative electrode current collector The negative electrode current collector is selected from copper foil.

在一些实施例中，所述负极材料层包括有负极活性材料、负极粘结剂和负极导电剂，所述负极活性材料、所述负极粘结剂和所述负极导电剂共混得到所述负极材料层。所述负极粘结剂包括聚偏氟乙烯、偏氟乙烯的共聚物、聚四氟乙烯、偏氟乙烯-六氟丙烯的共聚物、四氟乙烯-六氟丙烯的共聚物、四氟乙烯-全氟烷基乙烯基醚的共聚物、乙烯-四氟乙烯的共聚物、偏氟乙烯-四氟乙烯的共聚物、偏氟乙烯-三氟乙烯的共聚物、偏氟乙烯-三氯乙烯的共聚物、偏氟乙烯-氟代乙烯的共聚物、偏氟乙烯-六氟丙烯-四氟乙烯的共聚物、热塑性聚酰亚胺、聚乙烯及聚丙烯等热塑性树脂；丙烯酸类树脂；羟甲基纤维素钠；以及苯乙烯丁二烯橡胶中的一种或多种。 In some embodiments, the negative electrode material layer includes a negative electrode active material, a negative electrode binder and a negative electrode conductive agent, and the negative electrode active material, the negative electrode binder and the negative electrode conductive agent are blended to obtain the negative electrode material layer. The negative electrode binder includes polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, tetrafluoroethylene- Copolymer of perfluoroalkyl vinyl ether, copolymer of ethylene-tetrafluoroethylene, copolymer of vinylidene fluoride-tetrafluoroethylene, copolymer of vinylidene fluoride-trifluoroethylene, copolymer of vinylidene fluoride-trichloroethylene Copolymers, vinylidene fluoride-fluorovinyl copolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers, thermoplastic polyimides, polyethylene and polypropylene and other thermoplastic resins; acrylic resins; hydroxymethyl Sodium cellulose; and one or more of styrene butadiene rubber.

所述负极导电剂包括导电炭黑、导电碳球、导电石墨、导电碳纤维、碳纳米管、石墨烯或还原氧化石墨烯中的一种或多种。The negative electrode conductive agent includes one or more of conductive carbon black, conductive carbon balls, conductive graphite, conductive carbon fiber, carbon nanotubes, graphene or reduced graphene oxide.

在一些实施例中，所述电池中还包括有隔膜，所述隔膜位于所述正极和所述负极之间。In some embodiments, the battery further includes a separator located between the positive electrode and the negative electrode.

所述隔膜可为现有常规隔膜，可以是聚合物隔膜、无纺布等，包括但不限于单层PP(聚丙烯)、单层PE(聚乙烯)、双层PP/PE、双层PP/PP和三层PP/PE/PP等隔膜。The separator can be an existing conventional separator, and can be a polymer separator, non-woven fabric, etc., including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), double-layer PP/PE, double-layer PP /PP and three-layer PP/PE/PP and other separators.

以下通过实施例对本申请进行进一步的说明。The present application will be further described below through examples.

以下实施例和对比例涉及的化合物如下表1所示：The compounds involved in the following examples and comparative examples are shown in Table 1 below:

表1
Table 1

表2实施例和对比例各参数设计

Table 2 Parameter design of examples and comparative examples

实施例1Example 1

本实施例用于说明本申请实施例提供的锂离子电池及其制备方法，包括以下操作步骤：1-5。This example is used to illustrate the lithium-ion battery and its preparation method provided in the examples of this application, including the following steps: 1-5.

1)电解液的制备1) Preparation of electrolyte

将碳酸乙烯酯(EC)、碳酸二甲酯(DMC)和碳酸甲乙酯(EMC)进行混合，然后加入六氟磷酸锂(LiPF₆)至质量浓度为14.4％，加入添加剂。非水电解液中添加剂的选择、含量、环状碳酸酯的含量、电导率和总醇质量百分含量如表2所示。Mix ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC), then add lithium hexafluorophosphate (LiPF ₆ ) to a mass concentration of 14.4%, and add additives. The selection, content, cyclic carbonate content, conductivity and total alcohol mass percentage of the non-aqueous electrolyte are shown in Table 2.

2)正极板的制备2) Preparation of positive plate

按97:1.5:1.5的质量比混合正极活性材料LiNi_0.8Co_0.1Mn_0.1O₂、导电碳黑Super-P和粘结剂聚偏二氟乙烯(PVDF)，然后将它们分散在N-甲基-2-吡咯烷酮(NMP)中，得到正极浆料。将浆料均匀涂布在铝箔的两面上，经过烘干、压延和真空干燥，并用超声波焊机焊上铝制引出线后得到正极板，极板的厚度在120-150μm。Mix the cathode active material LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , conductive carbon black Super-P and binder polyvinylidene fluoride (PVDF) in a mass ratio of 97:1.5:1.5, and then disperse them in N-methyl -2-pyrrolidone (NMP) to obtain a positive electrode slurry. The slurry is evenly coated on both sides of the aluminum foil, dried, rolled and vacuum dried, and the aluminum lead wire is welded with an ultrasonic welder to obtain a positive plate with a thickness of 120-150 μm.

3)负极板的制备 3) Preparation of negative plate

按94:1.5:3:1.5的质量比混合负极活性材料石墨、导电碳黑Super-P，粘结剂丁苯橡胶(SBR)和羧甲基纤维素(CMC)，然后将它们分散在去离子水中，得到负极浆料。将浆料涂布在铜箔的两面上，经过烘干、压延和真空干燥，并用超声波焊机焊上镍制引出线后得到负极板，极板的厚度在120-150μm。Mix the negative active material graphite, conductive carbon black Super-P, binder styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) in a mass ratio of 94:1.5:3:1.5, and then disperse them in deionized In water, the negative electrode slurry is obtained. The slurry is coated on both sides of the copper foil, dried, rolled and vacuum dried, and a nickel lead wire is welded with an ultrasonic welder to obtain a negative plate with a thickness of 120-150 μm.

4)电芯的制备4) Preparation of battery core

在正极板和负极板之间放置厚度为20μm的三层隔离膜，然后将正极板、负极板和隔膜组成的三明治结构进行卷绕，再将卷绕体压扁后放入铝箔包装袋，在75℃下真空烘烤48h，得到待注液的电芯。Place a three-layer separator film with a thickness of 20 μm between the positive plate and the negative plate, then roll the sandwich structure composed of the positive plate, negative plate and separator, flatten the roll and put it into an aluminum foil packaging bag. Vacuum bake at 75°C for 48 hours to obtain the battery core to be injected.

5)电芯的注液和化成5) Liquid injection and formation of battery cells

在水氧含量分别20ppm、50ppm以下的手套箱中，将上述制备的电解液注入电芯中，经真空封装，45℃搁置24h。In a glove box with water and oxygen contents of 20 ppm and 50 ppm respectively, inject the electrolyte prepared above into the battery core, seal it in a vacuum, and leave it at 45°C for 24 hours.

然后按以下步骤进行首次充电的常规化成：0.05C恒流充电180min,0.1C恒流充电180min，0.2C恒流充电120min，在45℃老化48h后，二次真空封口，然后进一步以0.2C的电流恒流充电至4.2V，以0.2C的电流恒流放电至3V。实施例2～33Then follow the following steps to perform the conventional formation of the first charge: 0.05C constant current charging for 180min, 0.1C constant current charging for 180min, 0.2C constant current charging for 120min, aging at 45℃ for 48h, secondary vacuum sealing, and then further charging at 0.2C Charge to 4.2V with a constant current, and discharge to 3V with a constant current of 0.2C. Examples 2 to 33

实施例2～33用于说明本申请实施例提供的锂离子电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：Examples 2 to 33 are used to illustrate the lithium-ion battery and its preparation method provided in the examples of the present application, including most of the operating steps in Example 1, and the differences are:

采用表1所示的添加剂的选择、含量、环状碳酸酯的含量、电导率和总醇质量百分含量。The selection, content, cyclic carbonate content, electrical conductivity and total alcohol mass percentage shown in Table 1 were used.

对比例1～16Comparative Examples 1 to 16

对比例1～16用于对比说明本申请实施例提供的电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：Comparative Examples 1 to 16 are used to comparatively illustrate the battery and its preparation method provided in the embodiments of the present application, including most of the operating steps in Example 1, and the differences are:

性能测试Performance Testing

对上述制备得到的锂离子电池进行如下60℃存储性能测试：The lithium-ion battery prepared above was subjected to the following 60°C storage performance test:

将制备的锂离子电池恒流恒压充电至4.2V后置于恒温60℃的烘箱中保存，并在存储30天后进行放电容量、体积、内阻的测试。记录存储之前的放电容量和体积及阻抗，和存储30天之后的放电容量和体积及阻抗。The prepared lithium-ion battery was charged with constant current and constant voltage to 4.2V and then stored in an oven with a constant temperature of 60°C. After 30 days of storage, the discharge capacity, volume, and internal resistance were tested. Record discharge capacity before storage and volume and impedance, and discharge capacity, volume and impedance after 30 days of storage.

按下式计算高温存储的容量保持率、阻抗增长率和气胀率：
容量保持率＝存储后的放电容量/存储前的容量×100％；
阻抗增长率＝(存储后的阻抗-存储前的阻抗)/存储前的阻抗×100％；
气胀率＝(存储后电池体积-初始电池体积)/初始电池体积×100％。Calculate the capacity retention rate, impedance growth rate and inflation rate of high-temperature storage according to the following formula:
Capacity retention rate = discharge capacity after storage/capacity before storage × 100%;
Impedance growth rate = (impedance after storage - impedance before storage)/impedance before storage × 100%;
Inflation rate = (battery volume after storage - initial battery volume)/initial battery volume × 100%.

(1)实施例1～18和对比例1～11得到的测试结果填入表3。(1) The test results obtained in Examples 1 to 18 and Comparative Examples 1 to 11 are filled in Table 3.

表3
table 3

从表3的测试结果可以看出，在采用环状碳酸酯作为非水有机溶剂，甲醇和乙二醇的总醇量在500ppm及以下以及25℃下的电导率为7mS/cm～10.5mS/cm的非水电解液体系中，当非水电解液中第一添加剂的质量百分含量A 和非水电解液中第二添加剂的质量百分含量B满足关系式0.15≤A/(B*10)≤10.5时，得到的锂离子电池具有较低的阻抗、较高的高温存储容量保持率、较低的阻抗增长率和较低的气胀率，说明通过合理设置电解液条件，能够促进第一添加剂和第二添加剂在负极界面上的共同分解，形成低阻抗和高温稳定性较好的界面膜，能够有效抑制非水有机溶剂和有效锂盐在负极界面的持续分解。It can be seen from the test results in Table 3 that when cyclic carbonate is used as a non-aqueous organic solvent, the total alcohol content of methanol and ethylene glycol is 500ppm and below and the conductivity at 25°C is 7mS/cm~10.5mS/ cm non-aqueous electrolyte system, when the mass percentage of the first additive in the non-aqueous electrolyte A When the mass percentage B of the second additive in the non-aqueous electrolyte satisfies the relationship 0.15≤A/(B*10)≤10.5, the obtained lithium-ion battery has lower impedance and higher high-temperature storage capacity retention rate , lower impedance growth rate and lower gas expansion rate, indicating that by reasonably setting the electrolyte conditions, the joint decomposition of the first additive and the second additive on the negative electrode interface can be promoted to form a low impedance and good high temperature stability. The interfacial film can effectively inhibit the continued decomposition of non-aqueous organic solvents and effective lithium salts at the anode interface.

从实施例5～10的测试结果可以看出，在该电池体系中，随着第一添加剂的含量的提升，锂离子电池的高温存储容量保持率持续提升，阻抗增长率减低，但初期阻抗逐渐提升，说明第一添加剂中含有的环状硫酸酯结构分解形成的富含烷基亚硫酸锂(ROSO₂Li)的界面膜具有较好的高温稳定性，且能够有效抑制非水电解液的分解，进而减少界面膜阻抗的持续增加，但是该界面膜本身具有较高的阻抗；而从实施例1～4的测试结果可以看出，通过第二添加剂含量的提高，能够有效减低锂离子电池的初期阻抗，说明需要通过第二添加剂的添加，第二添加剂在羟基醇的作用下提高了该界面膜的无机成分含量，有效降低了界面膜的阻抗，进而使得锂离子电池同时具有较低的阻抗和高温存储性能。It can be seen from the test results of Examples 5 to 10 that in this battery system, as the content of the first additive increases, the high-temperature storage capacity retention rate of the lithium-ion battery continues to increase, and the impedance growth rate decreases, but the initial impedance gradually Improvement, indicating that the interfacial film rich in alkyl lithium sulfite (ROSO ₂ Li) formed by the decomposition of the cyclic sulfate ester structure contained in the first additive has good high-temperature stability and can effectively inhibit the decomposition of the non-aqueous electrolyte. , thereby reducing the continuous increase in the resistance of the interface film, but the interface film itself has a high resistance; and from the test results of Examples 1 to 4, it can be seen that by increasing the content of the second additive, the resistance of the lithium-ion battery can be effectively reduced. The initial impedance shows that the second additive needs to be added. The second additive increases the inorganic component content of the interface film under the action of hydroxyl alcohol, effectively reducing the impedance of the interface film, thereby making the lithium-ion battery have a lower impedance at the same time. and high temperature storage performance.

从对比例5～7、对比例10的测试结果可以看出，当采用PS(1,3-丙烷磺内酯)、PC(碳酸丙烯酯)EC(碳酸乙烯酯)或MMDS(甲基二磺酸亚甲酯)替代式I所示的化合物作为第一添加剂时，即使满足条件0.15≤A/(B*10)≤10.5的限制，锂离子电池的高温存储性能仍处于较低水平，说明本申请实施例提供的0.15≤A/(B*10)≤10.5是基于特定化合物设置的，对于其他成膜添加剂并不具有普适性。It can be seen from the test results of Comparative Examples 5 to 7 and Comparative Example 10 that when PS (1,3-propane sultone), PC (propylene carbonate), EC (ethylene carbonate) or MMDS (methyl disulfonate) are used, When methylene acid) replaces the compound shown in formula I as the first additive, even if the condition 0.15≤A/(B*10)≤10.5 is met, the high-temperature storage performance of the lithium-ion battery is still at a low level, indicating that this The 0.15≤A/(B*10)≤10.5 provided in the application examples is set based on specific compounds and is not universally applicable to other film-forming additives.

从对比例8、9和11的测试结果可知，即使非水电解液中第一添加剂的质量百分含量A和非水电解液中第二添加剂的质量百分含量B之间的关系满足条件0.15≤A/(B*10)≤10.5；但A值、B值不满足其范围限定时，锂离子电池仍然不具有较好的电化学性能。It can be seen from the test results of Comparative Examples 8, 9 and 11 that even if the relationship between the mass percentage A of the first additive in the non-aqueous electrolyte solution and the mass percentage B of the second additive in the non-aqueous electrolyte solution satisfies the condition 0.15 ≤A/(B*10)≤10.5; but when the A value and B value do not meet their range limits, the lithium-ion battery still does not have good electrochemical performance.

(2)实施例2、实施例19～26得到的测试结果填入表4。(2) The test results obtained in Example 2 and Examples 19 to 26 are filled in Table 4.

表4

Table 4

由实施例2、实施例19～26的测试结果可知，当采用不同的式I所示的化合物作为第一添加剂或不同的式II所示的化合物作为第二添加剂时，且非水电解液中第一添加剂的质量百分含量A和非水电解液中第二添加剂的质量百分含量B之间的关系满足条件0.15≤A/(B*10)≤10.5时，对于锂离子电池的提升作用是相似的，得到的锂离子电池的电化学性能优异，说明本申请实施例提供的关系式适用于不同的式I所示的化合物和式II所示的化合物。It can be seen from the test results of Example 2 and Examples 19 to 26 that when different compounds represented by formula I are used as the first additive or different compounds represented by formula II are used as the second additive, and in the non-aqueous electrolyte When the relationship between the mass percentage A of the first additive and the mass percentage B of the second additive in the non-aqueous electrolyte satisfies the condition 0.15≤A/(B*10)≤10.5, the improvement effect on lithium-ion batteries are similar, and the electrochemical performance of the obtained lithium-ion battery is excellent, indicating that the relational formula provided in the embodiments of the present application is applicable to different compounds represented by formula I and compounds represented by formula II.

(3)实施例27～30得到的测试结果填入表5。(3) The test results obtained in Examples 27 to 30 are filled in Table 5.

表5
table 5

由实施例27～30的测试结果可知，在本申请实施例提供的电池体系中，在非水电解液中加入上述LiPO₂F₂(二氟磷酸锂)、FEC(氟代碳酸乙烯酯)或PS(1,3-丙烷磺内酯)具有不同的影响效果，例如，实施例27和28中，通过添加LiPO₂F₂提升了电池的高温存储容量保持率；实施例29中，添加FEC则导致了气胀率的提高；实施例30中添加PS有利于降低阻抗增长率；推测是由于上述添加剂共同参与了电极表面界面膜的成型。It can be seen from the test results of Examples 27 to 30 that in the battery system provided by the Examples of the present application, the above-mentioned LiPO ₂ F ₂ (lithium difluorophosphate), FEC (fluoroethylene carbonate) or PS (1,3-propane sultone) has different effects. For example, in Examples 27 and 28, the high-temperature storage capacity retention rate of the battery is improved by adding LiPO ₂ F ₂ ; in Example 29, adding FEC This leads to an increase in the gas expansion rate; adding PS in Example 30 is beneficial to reducing the resistance growth rate; it is speculated that it is because the above additives jointly participate in the formation of the interface film on the electrode surface.

(4)实施例2、31～33和对比例12、13得到的测试结果填入表6。(4) The test results obtained in Examples 2, 31 to 33 and Comparative Examples 12 and 13 are filled in Table 6.

表6

Table 6

由实施例2、31～33和对比例12、13的测试结果可知，所述非水电解液中，通过控制环状碳酸酯在非水电解液中的含量，能够提高电解液溶剂的稳定性，有利于保证式I所示化合物和式II所示化合物分解后的负极界面膜的形成，避免电解液溶剂分解对于该负极界面膜性能的影响；从对比例12和对比例13的测试结果可知，当非水电解液中环状碳酸酯的含量过低或者环状碳酸酯的含量过高时，均不利于锂离子电池的阻抗的降低和高温存储性能的提升，说明环状碳酸酯含量过低在某些方面上影响到了负极界面膜的形成，而环状碳酸酯的含量过高时，电解液黏度增大，不利于锂离子的传输，导致电池离子电导率降低、阻抗增大。It can be seen from the test results of Examples 2, 31-33 and Comparative Examples 12 and 13 that in the non-aqueous electrolyte, by controlling the content of cyclic carbonate in the non-aqueous electrolyte, the stability of the electrolyte solvent can be improved , which is conducive to ensuring the formation of the negative electrode interface film after the decomposition of the compound represented by formula I and the compound represented by formula II, and avoiding the impact of the solvolysis of the electrolyte on the performance of the negative electrode interface film; it can be seen from the test results of Comparative Example 12 and Comparative Example 13 , when the content of cyclic carbonate in the non-aqueous electrolyte is too low or the content of cyclic carbonate is too high, it is not conducive to reducing the impedance of the lithium-ion battery and improving the high-temperature storage performance, indicating that the content of cyclic carbonate is too high. Low in some aspects affects the formation of the negative electrode interface film. When the content of cyclic carbonate is too high, the viscosity of the electrolyte increases, which is not conducive to the transmission of lithium ions, resulting in a decrease in battery ion conductivity and an increase in impedance.

(5)实施例2和对比例14-16得到的测试结果填入表7。(5) The test results obtained in Example 2 and Comparative Examples 14-16 are filled in Table 7.

表7
Table 7

由实施例2和对比例14-16的测试结果可知，在本申请实施例提供的总醇含量范围内，锂离子电池具有更好的高温存储性能，说明在本申请实施例提供的电池体系中，非水电解液中甲醇和乙二醇的总醇含量同样影响着电池的高温存储性能，推测是非水电解液中甲醇和乙二醇的总醇含量处于较低含量水平时利于电池循环性能的提升，而总醇含量过高时，非水电解液中活泼的醇羟基含量过高，易与锂盐等其他物质发生反应，导致活性锂离子含量降低，游离酸浓度增大，影响负极界面膜的成型，最终导致锂离子电池的循环性能下降。It can be seen from the test results of Example 2 and Comparative Examples 14-16 that within the total alcohol content range provided by the Examples of the present application, the lithium-ion battery has better high-temperature storage performance, indicating that in the battery system provided by the Examples of the present application , the total alcohol content of methanol and ethylene glycol in the non-aqueous electrolyte also affects the high-temperature storage performance of the battery. It is speculated that when the total alcohol content of methanol and ethylene glycol in the non-aqueous electrolyte is at a lower level, it is beneficial to the battery cycle performance. When the total alcohol content is too high, the content of active alcoholic hydroxyl groups in the non-aqueous electrolyte is too high, which easily reacts with other substances such as lithium salts, resulting in a decrease in the content of active lithium ions and an increase in the concentration of free acid, affecting the negative electrode interface film. molding, ultimately leading to a decline in the cycle performance of lithium-ion batteries.

以上所述仅为本申请的较佳实施例而已，并不用以限制本申请，凡在本申请的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本申请的保护范围之内。 The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the protection of the present application. within the range.

Claims

一种非水电解液，其特征在于，包括非水有机溶剂、电解质盐和添加剂，所述非水有机溶剂包括环状碳酸酯，所述环状碳酸酯在所述非水有机溶剂中的质量百分含量为10～40％；A non-aqueous electrolyte, characterized in that it includes a non-aqueous organic solvent, an electrolyte salt and an additive, the non-aqueous organic solvent includes a cyclic carbonate, and the mass of the cyclic carbonate in the non-aqueous organic solvent The percentage content is 10~40%;

所述添加剂包括式I所示的第一添加剂和式II所示的第二添加剂，所述第一添加剂的还原电位在0.95V以上；
The additive includes a first additive represented by Formula I and a second additive represented by Formula II, and the reduction potential of the first additive is above 0.95V;

其中，R₁选自C或O，R₂选自R₃选自亚甲基、R₄选自H、且R₂、R₃和R₄中至少含有一个硫原子；
Among them, R ₁ is selected from C or O, and R ₂ is selected from R ₃ is selected from methylene, R ₄ is selected from H, And R ₂ , R ₃ and R ₄ contain at least one sulfur atom;

其中，R₅选自C1-C5的饱和烃基、C1-C5的不饱和烃基、C1-C5的卤代烃基、芳香基和-Si(C_mH_2m+1)₃及其卤代物，m为1～3的自然数；Wherein, R ₅ is selected from C1-C5 saturated hydrocarbon group, C1-C5 unsaturated hydrocarbon group, C1-C5 halogenated hydrocarbon group groups, aromatic groups and -Si(C _m H _2m+1 ) ₃ and its halogenated compounds, m is a natural number from 1 to 3;

所述非水电解液满足以下条件：The non-aqueous electrolyte meets the following conditions:

0.05％≤A≤1.8％；0.05%≤A≤1.8%;

0.01％≤B≤0.2％；0.01%≤B≤0.2%;

0.15≤A/(B*10)≤10.5；0.15≤A/(B*10)≤10.5;

其中，A为非水电解液中第一添加剂的质量百分含量，单位为％；Among them, A is the mass percentage of the first additive in the non-aqueous electrolyte, in %;

B为非水电解液中第二添加剂的质量百分含量，单位为％；B is the mass percentage of the second additive in the non-aqueous electrolyte, in %;

所述非水电解液在25℃下的电导率为7mS/cm～10.5mS/cm，且所述非水电解液中甲醇和乙二醇的总醇含量在500ppm及以下。The non-aqueous electrolyte has a conductivity of 7 mS/cm to 10.5 mS/cm at 25°C, and the total alcohol content of methanol and ethylene glycol in the non-aqueous electrolyte is 500 ppm and below.
根据权利要求1所述的非水电解液，其特征在于，所述第一添加剂的还原电位为0.95～1.35V，且非水电解液中所述第一添加剂的质量百分含量A为0.2％～1.5％。The non-aqueous electrolyte according to claim 1, wherein the reduction potential of the first additive is 0.95-1.35V, and the mass percentage A of the first additive in the non-aqueous electrolyte is 0.2%. ~1.5%.
根据权利要求1或2所述的非水电解液，其特征在于，所述非水电解液满足以下条件：The non-aqueous electrolyte solution according to claim 1 or 2, characterized in that the non-aqueous electrolyte solution satisfies the following conditions:

0.4≤A/(B*10)≤10。0.4≤A/(B*10)≤10.
根据权利要求1至3中任一项所述的非水电解液，其特征在于，所述式I所示的第一添加剂选自以下化合物中的一种或多种：

The non-aqueous electrolyte solution according to any one of claims 1 to 3, characterized in that the first additive represented by Formula I is selected from one or more of the following compounds:
根据权利要求1至4中任一项所述的非水电解液，其特征在于，所述式II所示的第二添加剂选自以下化合物中的一种或多种：
The non-aqueous electrolyte solution according to any one of claims 1 to 4, characterized in that the second additive represented by Formula II is selected from one or more of the following compounds:
根据权利要求1至5中任一项所述的非水电解液，其特征在于，所述环状碳酸酯选自碳酸乙烯酯、碳酸丙烯酯、氟代碳酸乙烯酯中的至少一种。The non-aqueous electrolyte solution according to any one of claims 1 to 5, wherein the cyclic carbonate is selected from at least one selected from the group consisting of ethylene carbonate, propylene carbonate, and fluorinated ethylene carbonate.
根据权利要求1至6中任一项所述的非水电解液，其特征在于，所述电解质盐选自LiPF₆、LiBOB、LiDFOB、LiDFOP、LiPO₂F₂、LiBF₄、LiSbF₆、LiAsF₆、LiN(SO₂CF₃)₂、LiN(SO₂C₂F₅)₂、LiC(SO₂CF₃)₃、LiN(SO₂F)₂、LiClO₄、LiAlCl₄、LiCF₃SO₃、Li₂B₁₀Cl₁₀、低级脂肪族羧酸锂盐中的至少一种。The non-aqueous electrolyte solution according to any one of claims 1 to 6, characterized in that the electrolyte salt is selected from the group consisting of LiPF ₆ , LiBOB, LiDFOB, LiDFOP, LiPO ₂ F ₂ , LiBF ₄ , LiSbF ₆ , and LiAsF ₆ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ , LiC(SO ₂ CF ₃ ) ₃ , LiN(SO ₂ F) ₂ , LiClO ₄ , LiAlCl ₄ , LiCF ₃ SO ₃ , Li ₂ B ₁₀ Cl ₁₀ and at least one of lower aliphatic carboxylic acid lithium salts.
根据权利要求1至7中任一项所述的非水电解液，其特征在于，所述非水电解液中还包括第三添加剂，所述第三添加剂包括磺酸内酯类化合物、环状碳酸酯类化合物、二氟磷酸锂和腈类化合物中的至少一种；以所述非水电解液的总质量为100％计，所述第三添加剂的添加量为0.01％～30％。The non-aqueous electrolyte according to any one of claims 1 to 7, characterized in that the non-aqueous electrolyte further includes a third additive, and the third additive includes a sultone compound, a cyclic At least one of carbonate compounds, lithium difluorophosphate and nitrile compounds; based on the total mass of the non-aqueous electrolyte being 100%, the addition amount of the third additive is 0.01% to 30%.
根据权利要求8所述的非水电解液，其特征在于，所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯或1,3-丙烯磺酸内酯中的至少一种；The non-aqueous electrolyte according to claim 8, wherein the sultone compound is selected from the group consisting of 1,3-propane sultone, 1,4-butane sultone or 1,3-propane sultone. -At least one kind of propylene sultone;

所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、氟代碳酸乙烯酯或式Ⅲ所示化合物中的至少一种，
The cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate or the compound represented by formula III,

所述式Ⅲ中，R₂₁、R₂₂、R₂₃、R₂₄、R₂₅、R₂₆各自独立地选自氢原子、卤素原子、C1-C5基团中的一种；In the formula III, R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , and R ₂₆ are each independently selected from one of hydrogen atoms, halogen atoms, and C1-C5 groups;

所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的一种或多种。The nitrile compound is selected from succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelonitrile, and sebaconitrile. of one or more.
一种二次电池，其特征在于，包括正极、负极以及如权利要求1至9中任意一项所述的非水电解液。 A secondary battery, characterized by comprising a positive electrode, a negative electrode and the non-aqueous electrolyte solution according to any one of claims 1 to 9.