WO2022205065A1

WO2022205065A1 - Electrolyte solution, electrochemical device, and electronic device

Info

Publication number: WO2022205065A1
Application number: PCT/CN2021/084396
Authority: WO
Inventors: 王蕊; 王翔; 唐超
Original assignee: 宁德新能源科技有限公司
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2022-10-06
Also published as: CN114287079B; CN114287079A

Abstract

Provided are an electrolyte solution, an electrochemical device, and an electronic device. The electrolyte solution comprises a compound represented by formula (I), in which R₁₁ is selected from a covalent bond, oxygen, sulfur, a C₁-C₁₀ hydrocarbylene, a C₁-C₅ alkyleneoxy or a C₁-C₅ alkylenethio, wherein the hydrocarbylene group includes an alkylene, an alkenylene, and an arylene; R₁₂ is selected from a covalent bond, a C₁-C₁₀ hydrocarbylene or a C₁-C₁₀ hydrocarbylsulfonyl, wherein the hydrocarbylene group includes an alkylene, an alkenylene, and an arylene; and X is selected from a substituted or unsubstituted C₁-C₁₀ heterocyclic group containing at least one of an oxygen, nitrogen, or sulfur atom, wherein when substitution occurs, the substituent includes hydrocarbyl, cyano and a halogen atom, the hydrocarbyl includes alkyl, alkenyl and alkynyl, and the heterocyclic ring includes a cyclic ether, morpholine, pyridine, triazole, furan, pyran, piperidine, pyrrole, pyrazole, pyrazine, pyridazine, and imidazole. The electrolyte solution can significantly improve the high-temperature cycling performance of an electrochemical device at a high voltage of 4.4 V to 4.8 V, and can reduce the increase in the cycling impedance.

Description

电解液、电化学装置以及电子装置Electrolytes, electrochemical devices, and electronic devices

技术领域technical field

本申请涉及电化学领域，具体涉及一种电解液、电化学装置以及电子装置。The present application relates to the field of electrochemistry, and in particular, to an electrolyte, an electrochemical device, and an electronic device.

背景技术Background technique

伴随近年来电气制品的轻量化、小型化，对于电化学装置(例如，锂离子电池)在轻薄方面的需求也在不断提高。具有高能量密度的锂离子二次电池的开发正在逐步推进，其设计的使用上限电压也随之提高，目前钴酸锂体系的锂离子电池额定电压可达4.45V至4.5V，这意味着高电压存储及充放电，对正、负极结构的破坏愈加严重，因此对电解液本身的耐氧化能力及成膜稳定性都提出了更高的需求。With the recent reduction in weight and size of electrical products, the demand for light and thin electrochemical devices (eg, lithium ion batteries) is also increasing. The development of lithium-ion secondary batteries with high energy density is gradually advancing, and the upper limit voltage of its design is also increased. At present, the rated voltage of lithium-ion batteries of lithium cobalt oxide system can reach 4.45V to 4.5V, which means high Voltage storage and charging and discharging have more and more serious damage to the structure of the positive and negative electrodes. Therefore, higher requirements are placed on the oxidation resistance and film-forming stability of the electrolyte itself.

一般改善电解液耐氧化能力的方法包括：使用氟代酯、氟代醚等氧化电位较高的惰性溶剂；提高腈类或丙烷磺内酯等添加剂的含量。但氟代溶剂粘度大，离子传输能力弱，很难实现高电压下快速充电；而增大添加剂用量，会进一步恶化电解液的电导率和电池阻抗。The general methods for improving the oxidation resistance of the electrolyte include: using inert solvents with high oxidation potential such as fluorinated esters and fluorinated ethers; increasing the content of additives such as nitrile or propane sultone. However, fluorinated solvents have high viscosity and weak ion transport ability, making it difficult to achieve fast charging at high voltages; and increasing the amount of additives will further deteriorate the conductivity of the electrolyte and battery impedance.

因此，如何开发出能够改善高电压下电池循环性能的电解液添加剂，成为提高电池性能的重要课题。Therefore, how to develop electrolyte additives that can improve battery cycle performance under high voltage has become an important issue to improve battery performance.

发明内容SUMMARY OF THE INVENTION

在一些实施例中，本申请提供了一种电解液，其包括式(I)表示的化合物，In some embodiments, the application provides an electrolyte solution comprising a compound represented by formula (I),

在式(I)中，R ₁₁选自共价键、氧、硫、C ₁-C ₁₀亚烃基、C ₁-C ₅亚烷氧基或C ₁-C ₅亚烷硫基，所述亚烃基包括亚烷基、亚烯基或亚芳基； In formula (I), R ₁₁ is selected from covalent bonds, oxygen, sulfur, C ₁ -C ₁₀ alkylene, C ₁ -C ₅ alkyleneoxy or C ₁ -C ₅ alkylenethio, the Hydrocarbyl includes alkylene, alkenylene or arylene;

R ₁₂选自共价键、C ₁-C ₁₀亚烃基或C ₁-C ₁₀亚烃基磺酰基，所述亚烃基包括亚烷基、亚烯基或亚芳基； R ₁₂ is selected from a covalent bond, a C ₁ -C ₁₀ hydrocarbylene group or a C ₁ -C ₁₀ hydrocarbylene sulfonyl group, the hydrocarbylene group includes an alkylene group, an alkenylene group or an arylene group;

X选自经取代或未经取代的C ₁-C ₁₀的含氧、氮或硫原子中至少一种的杂环基；经取代时，取代基包括烃基、氰基或卤素，所述烃基包括烷基、烯基或炔基；所述杂环包括环醚、吗啉、吡啶、三氮唑、呋喃、吡喃、哌啶、吡咯、吡唑、吡嗪、哒嗪或咪唑中的至少一种。 X is selected from substituted or unsubstituted C ₁ -C ₁₀ heterocyclic groups containing at least one of oxygen, nitrogen or sulfur atoms; when substituted, the substituents include hydrocarbyl, cyano or halogen, and the hydrocarbyl includes Alkyl, alkenyl or alkynyl; the heterocycle includes at least one of cyclic ether, morpholine, pyridine, triazole, furan, pyran, piperidine, pyrrole, pyrazole, pyrazine, pyridazine or imidazole kind.

在一些实施例中，所述式(I)表示的化合物包括式(I-1)至式(I-7)表示的化合物中的至少一种；In some embodiments, the compound represented by formula (I) includes at least one of compounds represented by formula (I-1) to formula (I-7);

在一些实施例中，基于所述电解液的重量，所述式(I)表示的化合物的含量为n％，0.02≤n≤7。In some embodiments, based on the weight of the electrolyte, the content of the compound represented by the formula (I) is n %, 0.02≤n≤7.

在一些实施例中，电解液还包括氟代碳酸乙烯酯、碳酸亚乙烯酯中的至少一种；基于所述电解液的重量，氟代碳酸乙烯酯的含量为k％，碳酸亚乙烯酯的含量为m％，其中，k≥0，m≥0，k+m＞0，且k、m和n满足-1≤k+m-n≤12。In some embodiments, the electrolyte further includes at least one of fluoroethylene carbonate and vinylene carbonate; based on the weight of the electrolyte, the content of fluoroethylene carbonate is k %, and the content of vinylene carbonate is k%. The content is m%, wherein k≥0, m≥0, k+m>0, and k, m and n satisfy -1≤k+m-n≤12.

在一些实施例中，0＜k+m≤14。In some embodiments, 0<k+m≤14.

在一些实施例中，所述电解液还包括羧酸酯；基于所述电解液的重量，所述羧酸酯的含量为a％，5≤a≤30，且a和n满足关系：0.0005≤n/a≤0.7。在一些实施例中，0.05≤n/a≤0.1。In some embodiments, the electrolyte further includes carboxylate; based on the weight of the electrolyte, the content of the carboxylate is a%, 5≤a≤30, and a and n satisfy the relationship: 0.0005≤ n/a≤0.7. In some embodiments, 0.05≤n/a≤0.1.

在一些实施例中，所述羧酸酯包括乙酸乙酯、乙酸丙酯、乙酸丁酯、丙酸乙酯、丙酸丙酯、丙酸丁酯中的至少一种。In some embodiments, the carboxylate includes at least one of ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, and butyl propionate.

在一些实施例中，所述电解液还包括磺酸酯类化合物或腈类化合物中的至少一种。In some embodiments, the electrolyte further includes at least one of a sulfonate compound or a nitrile compound.

在一些实施例中，磺酸酯类化合物包括1,3-丙烷磺内酯、2,4-丁磺内酯中的至少一种。In some embodiments, the sulfonate compound includes at least one of 1,3-propane sultone and 2,4-butane sultone.

在一些实施例中，基于所述电解液的重量，所述磺酸酯类化合物的含量为0.1-5％。In some embodiments, the content of the sulfonate compound is 0.1-5% based on the weight of the electrolyte.

在一些实施例中，所述腈类化合物包括式(Ⅱ)至式(Ⅴ)表示的化合物中的至少一种；In some embodiments, the nitrile compound includes at least one of the compounds represented by formula (II) to formula (V);

其中，R ₂₁选自经取代或未经取代的C ₁-C ₁₂亚烷基、经取代或未经取代的C ₁-C ₁₂亚烷氧基；R ₃₁、R ₃₂各自独立地选自共价键、经取代或未经取代的C ₁-C ₁₂亚烷基；R ₄₁、R ₄₂、R ₄₃各自独立地选自共价键、经取代或经未取代的C ₁-C ₁₂亚烷基、经取代或未经取代的C ₁-C ₁₂亚烷氧基；R ₅₁选自经取代或经未经取代的C ₁-C ₁₂亚烷基、经取代或未经取代的C ₂-C ₁₂亚烯基、经取代或未经取代的C ₆-C ₁₂亚芳基、经取代或未经取代的C ₃-C ₁₂亚环基；其中经取代时，取代基为卤素。 Wherein, R ₂₁ is selected from substituted or unsubstituted C ₁ -C ₁₂ alkylene, substituted or unsubstituted C ₁ -C ₁₂ alkyleneoxy; R ₃₁ and R ₃₂ are independently selected from co- Bond, substituted or unsubstituted C ₁ -C ₁₂ alkylene; R ₄₁ , R ₄₂ , R ₄₃ are each independently selected from covalent bond, substituted or unsubstituted C ₁ -C ₁₂ alkylene group, substituted or unsubstituted C ₁ -C ₁₂ alkyleneoxy; R ₅₁ is selected from substituted or unsubstituted C ₁ -C ₁₂ alkylene, substituted or unsubstituted C ₂ - C ₁₂ alkenylene, substituted or unsubstituted C ₆ -C ₁₂ arylene, substituted or unsubstituted C ₃ -C ₁₂ cyclylene; wherein when substituted, the substituent is halogen.

在一些实施例中，所述腈类化合物包括以下化合物中的至少一种；In some embodiments, the nitrile compound includes at least one of the following compounds;

在一些实施例中，基于所述电解液的重量，所述腈类化合物的含量为0.05-10％。In some embodiments, the content of the nitrile compound is 0.05-10% based on the weight of the electrolyte.

在一些实施例中，本申请还提供了一种电化学装置，其包括正极、负极、隔离膜以及本申请所述的电解液。In some embodiments, the present application also provides an electrochemical device, which includes a positive electrode, a negative electrode, a separator, and the electrolyte described in the present application.

在一些实施例中，所述电化学装置的充电截止电压为4.4至4.8V。In some embodiments, the electrochemical device has a charge cutoff voltage of 4.4 to 4.8V.

进一步，本申请还提供了一种电子装置，其包括本申请所述的电化学装置。Further, the present application also provides an electronic device comprising the electrochemical device described in the present application.

本申请提供的电解液可以显著改善电化学装置的在4.4V至4.8V高电压下的高温循环性能，降低循环阻抗增长。The electrolyte provided by the present application can significantly improve the high-temperature cycle performance of the electrochemical device at a high voltage of 4.4V to 4.8V, and reduce the increase in cycle impedance.

具体实施方式Detailed ways

应理解的是，所公开的实施例仅是本申请的示例，本申请可以以各种形式实施，因此，本文公开的具体细节不应被解释为限制，而是仅作为权利要求的基础且作为表示性的基础用于教导本领域普通技术人员以各种方式实施本申请。It is to be understood that the disclosed embodiments are merely exemplary of the application, which may be embodied in various forms, and therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as A representative basis is provided for teaching one of ordinary skill in the art to variously implement the application.

在本申请的说明中，除非另有说明，所有化合物的基团可以是经取代的或未经取代的。In the description of this application, unless otherwise stated, the groups of all compounds may be substituted or unsubstituted.

在本申请的说明中，术语“杂原子”表示除C、H以外的原子。在一些实施例中，杂原子包括B、N、O、Si、P、S中的至少一种。在本申请的说明中，术语“杂环基”是指包含至少一个杂原子的环基。在一些实施例中，杂环基包含含氧、氮或硫原子中至少一种的杂环基。在一些实施例中，杂环包含环醚、吗啉、吡啶、三氮唑、呋喃、吡喃、哌啶、吡咯、吡唑、吡嗪、哒嗪、咪唑。In the description of this application, the term "heteroatom" refers to atoms other than C, H. In some embodiments, the heteroatoms include at least one of B, N, O, Si, P, S. In the specification of this application, the term "heterocyclyl" refers to a cyclic group containing at least one heteroatom. In some embodiments, the heterocyclyl group comprises a heterocyclyl group containing at least one of oxygen, nitrogen, or sulfur atoms. In some embodiments, the heterocycle comprises a cyclic ether, morpholine, pyridine, triazole, furan, pyran, piperidine, pyrrole, pyrazole, pyrazine, pyridazine, imidazole.

在本申请的说明中，亚烃基为烃基失去一个氢原子形成的二价基团。亚烷基为烷基失去一个氢原子形成的二价基团，亚烯基为烯基失去一个氢原子形成的二价基团，亚芳基为芳基失去一个氢原子形成的二价基团。在本申请的说明中，未明确说明的亚基结构均按照本段的说明解读。In the specification of this application, a hydrocarbylene group is a divalent group formed by the loss of one hydrogen atom of a hydrocarbyl group. An alkylene group is a divalent group formed by the loss of one hydrogen atom from an alkyl group, an alkenylene group is a divalent group formed by the loss of a hydrogen atom from an alkenyl group, and an arylene group is a divalent group formed by the loss of a hydrogen atom from an aryl group . In the description of this application, the subunit structures that are not explicitly described are all interpreted according to the description of this paragraph.

在本申请的说明中，亚烷氧基为醚失去两个氢原子形成的二价基团，所述醚可以包含一个或多个醚键。In the specification of the present application, an alkyleneoxy group is a divalent group formed by the loss of two hydrogen atoms of an ether, which may contain one or more ether linkages.

在本申请的说明中，环醚可以包含一个或多个醚键。In the specification of the present application, the cyclic ether may contain one or more ether linkages.

在本申请的说明中，未明确说明的术语、结构式中的取代等，均应按照本领域普通技术人员的公知的、常规的、惯用的手段或方式理解。In the description of the present application, terms that are not explicitly described, substitutions in structural formulas, etc., should be understood according to the well-known, conventional, and usual means or manners of those of ordinary skill in the art.

下面详细说明本申请的电解液、电化学装置及电子装置。The electrolyte solution, electrochemical device, and electronic device of the present application will be described in detail below.

[电解液][electrolyte]

<添加剂A><Additive A>

在一些实施例中，电解液中含有添加剂A，添加剂A为式(I)表示的化合物中的至少一种；In some embodiments, the electrolyte contains additive A, which is at least one of the compounds represented by formula (I);

在式(I)中，R ₁₁选自共价键、氧、硫、C ₁-C ₁₀亚烃基、C ₁-C ₅亚烷氧基或C ₁-C ₅亚烷硫基，所述亚烃基包括亚烷基、亚烯基或亚芳基；R ₁₂选自共价键、C ₁-C ₁₀亚烃基或C ₁-C ₁₀亚烃基磺酰基，所述亚烃基包括亚烷基、亚烯基或亚芳基；X选自经取代或未经取代的C ₁-C ₁₀的含氧、氮或硫原子中至少一种的杂环基；经取代时，取代基包括烃基、氰基或卤素，所述烃基包括烷基、烯基或炔基；所述杂环包括环醚、吗啉、吡啶、三氮唑、呋喃、吡喃、哌啶、吡咯、吡唑、吡嗪、哒嗪或咪唑中的至少一种。 In formula (I), R ₁₁ is selected from covalent bonds, oxygen, sulfur, C ₁ -C ₁₀ alkylene, C ₁ -C ₅ alkyleneoxy or C ₁ -C ₅ alkylenethio, the Hydrocarbyl includes alkylene, alkenylene or arylene; R ₁₂ is selected from covalent bond, C ₁ -C ₁₀ hydrocarbylene or C ₁ -C ₁₀ hydrocarbylene sulfonyl, and the hydrocarbylene includes alkylene, Alkenyl or arylene; X is selected from substituted or unsubstituted C ₁ -C ₁₀ heterocyclic groups containing at least one of oxygen, nitrogen or sulfur atoms; when substituted, the substituents include hydrocarbyl, cyano or halogen, the hydrocarbyl includes alkyl, alkenyl or alkynyl; the heterocycle includes cyclic ether, morpholine, pyridine, triazole, furan, pyran, piperidine, pyrrole, pyrazole, pyrazine, pyridyl at least one of oxazine or imidazole.

在本申请的电解液中，添加剂A为杂环取代的糠醛衍生物，其中的醛基可以加强SEI(Solid Electrolyte Interphase，固体电解质界面)稳定性，含杂原子及杂环的错位取代基团同样具有成膜效果，特别是含氮、含硫类，使该物质可以具备保护正、负极的双功能，实现对电化学装置在4.4V至4.8V高电压下的高温循环性能的显著改善，并且降低电化学装置在该化学体系下的循环阻抗增长。In the electrolyte of the present application, additive A is a heterocyclic substituted furfural derivative, and the aldehyde group in it can enhance the stability of SEI (Solid Electrolyte Interphase, solid electrolyte interface), and the dislocation substitution group containing heteroatoms and heterocycles is also the same It has a film-forming effect, especially nitrogen-containing and sulfur-containing types, so that the material can have the dual function of protecting the positive and negative electrodes, and achieve a significant improvement in the high-temperature cycle performance of the electrochemical device at a high voltage of 4.4V to 4.8V, and Reduce the cycle impedance growth of the electrochemical device under this chemical system.

在一些实施例中，式(I)表示的化合物包含式(I-1)至式(I-7)表示的化合物中的至少一种；In some embodiments, the compound represented by formula (I) comprises at least one of compounds represented by formula (I-1) to formula (I-7);

在一些实施例中，基于所述电解液的重量，式(I)表示的化合物的含量为n％，0.02≤n≤7。In some embodiments, based on the weight of the electrolyte, the content of the compound represented by formula (I) is n %, 0.02≤n≤7.

<添加剂B><Additive B>

在一些实施例中，电解液中可还包含添加剂B，添加剂B为氟代碳酸乙烯酯、碳酸亚乙烯酯中的至少一种。In some embodiments, the electrolyte may further include an additive B, and the additive B is at least one of fluoroethylene carbonate and vinylene carbonate.

在一些实施例中，基于所述电解液的重量，氟代碳酸乙烯酯的含量为k％，碳酸亚乙烯酯的含量为m％，其中，k≥0，m≥0，0＜k+m≤14，且k、m和n满足-1≤k+m-n≤12。In some embodiments, based on the weight of the electrolyte, the content of fluoroethylene carbonate is k%, and the content of vinylene carbonate is m%, wherein k≥0, m≥0, 0<k+m ≤14, and k, m, and n satisfy -1≤k+m-n≤12.

<添加剂C><Additive C>

在一些实施例中，电解液中可还包含磺酸酯类化合物或腈类化合物中的至少一种。In some embodiments, the electrolyte may further contain at least one of sulfonate compounds or nitrile compounds.

在一些实施例中，基于所述电解液的重量，所述磺酸酯类化合物的含量为0.1％-5％。In some embodiments, based on the weight of the electrolyte, the content of the sulfonate compound is 0.1%-5%.

在一些实施例中，腈类化合物包含式(Ⅱ)至式(Ⅴ)表示的化合物中的至少一种；In some embodiments, the nitrile compound comprises at least one of the compounds represented by formula (II) to formula (V);

在一些实施例中，腈类化合物包含以下化合物中的至少一种：In some embodiments, the nitrile compound comprises at least one of the following compounds:

在一些实施例中，基于所述电解液的重量，所述腈类化合物的含量为0.1-10％。In some embodiments, the content of the nitrile compound is 0.1-10% based on the weight of the electrolyte.

<有机溶剂><Organic solvent>

在一些实施例中，电解液还包含有机溶剂。有机溶剂是本领域技术公知的适用于电化学装置的有机溶剂，例如通常使用非水有机溶剂。在一些实施例中，非水有机溶剂包含碳酸酯类溶剂、羧酸酯类溶剂中的至少一种。In some embodiments, the electrolyte further includes an organic solvent. The organic solvent is an organic solvent known to those skilled in the art and suitable for electrochemical devices, for example, a non-aqueous organic solvent is generally used. In some embodiments, the non-aqueous organic solvent includes at least one of a carbonate-based solvent and a carboxylate-based solvent.

在一些实施例中，碳酸酯类溶剂包含碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸二丙酯、碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯中的至少一种。In some embodiments, the carbonate-based solvent comprises dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, ethylene carbonate, propylene carbonate, carbonic acid At least one of butene esters.

在一些实施例中，羧酸酯类溶剂包含乙酸乙酯、乙酸丙酯、乙酸丁酯、丙酸乙酯、丙酸丙酯、丙酸丁酯中的至少一种。In some embodiments, the carboxylate-based solvent includes at least one of ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, and butyl propionate.

在一些实施例中，基于所述电解液的重量，所述羧酸酯的含量为a％，当电解液中含有含量为n％的式(I)表示的化合物时，5≤a≤30，且a和n满足关系：0.0005≤n/a≤0.7，如果n/a比例较低，则电解液无法在正极形成有效保护层，溶剂容易分解产气；如果n/a比例过高，则负极成膜阻抗大，不能提供通畅的锂离子传输通道。在一些实施例中，0.05≤n/a≤0.1。In some embodiments, based on the weight of the electrolyte, the content of the carboxylate is a%, and when the electrolyte contains n% of the compound represented by the formula (I), 5≤a≤30, And a and n satisfy the relationship: 0.0005≤n/a≤0.7, if the ratio of n/a is low, the electrolyte cannot form an effective protective layer on the positive electrode, and the solvent is easily decomposed to produce gas; if the ratio of n/a is too high, the negative electrode The film-forming resistance is large and cannot provide a smooth lithium ion transport channel. In some embodiments, 0.05≤n/a≤0.1.

在本申请中，电解液中的有机溶剂可以使用一种非水有机溶剂，也可以使用多种非水有机溶剂混合，当使用混合溶剂时，可以通过控制混合比获得不同性能的电化学装置。In the present application, one non-aqueous organic solvent can be used as the organic solvent in the electrolyte, or multiple non-aqueous organic solvents can be mixed. When mixed solvents are used, electrochemical devices with different performances can be obtained by controlling the mixing ratio.

<电解质盐><Electrolyte salt>

在一些实施例中，电解液还包含电解质盐。电解质盐是本领域技术公知的适用于电化学装置的电解质盐。针对不同的电化学装置，可以选用合适的电解质盐。例如对于锂离子电池，电解质盐通常使用锂盐。In some embodiments, the electrolyte further includes an electrolyte salt. Electrolyte salts are those known to those skilled in the art that are suitable for use in electrochemical devices. Appropriate electrolyte salts can be selected for different electrochemical devices. For example, for lithium ion batteries, lithium salts are generally used as electrolyte salts.

在一些实施例中，锂盐包含有机锂盐或无机锂盐中的至少一种。In some embodiments, the lithium salt comprises at least one of an organic lithium salt or an inorganic lithium salt.

在一些实施例中，锂盐包含LiPF ₆、LiBF ₄、LiB(C ₆H ₅) ₄、LiCH ₃SO ₃、LiCF ₃SO ₃、LiN(SO ₂CF ₃) ₂、LiC(SO ₂CF ₃) ₃、LiSiF ₆、LiBOB或LiDFOB中的至少一种，优选LiPF ₆。 In some embodiments, the lithium salt includes LiPF ₆ , LiBF ₄ , LiB(C ₆ H ₅ ) ₄ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiN(SO ₂ CF ₃ ) ₂ , LiC(SO ₂ CF ₃ ) _3. At least one of LiSiF ₆ , LiBOB or LiDFOB, preferably LiPF ₆ .

在本申请中，电解液的含量不受具体限制，可根据实际需要进行合理添加。在本申请中，电解液的制备方法不受限制，可按照本领域技术人员公知的常规电解液的制备方法制备得到。In this application, the content of the electrolyte is not specifically limited, and can be reasonably added according to actual needs. In the present application, the preparation method of the electrolyte solution is not limited, and can be prepared according to the conventional preparation method of the electrolyte solution known to those skilled in the art.

[电化学装置][Electrochemical device]

其次说明本申请的电化学装置。Next, the electrochemical device of the present application will be described.

本申请电化学装置可以是选自如下装置中的任意一种：锂二次电池或钠离子电池。特别地，所述电化学装置为锂二次电池。The electrochemical device of the present application may be any one selected from the following devices: a lithium secondary battery or a sodium ion battery. In particular, the electrochemical device is a lithium secondary battery.

在一些实施例中，电化学装置包含正极片、负极片、隔离膜以及本申请前述的电解液。In some embodiments, the electrochemical device includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte as previously described herein.

<正极片><Positive electrode>

正极片是本领域技术公知的可被用于电化学装置的正极片。在一些实施例中，正极片包含正极集流体以及设置在正极集流体上的正极活性物质层。正极活性物质层可包含正极活性物质、正极导电剂以及正极粘结剂。The positive electrode sheet is known in the art as a positive electrode sheet that can be used in electrochemical devices. In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector. The positive electrode active material layer may contain a positive electrode active material, a positive electrode conductive agent, and a positive electrode binder.

在一些实施例中，正极活性物质包含钴酸锂(LCO)、锂镍锰钴三元材料(NCM)、磷酸铁锂、磷酸锰铁锂、锰酸锂中的至少一种。在一些实施例中，当电化学装置采用LCO、NCM体系时，采用本申请所提供电解液添加剂能获得进一步的电化学性能。In some embodiments, the positive active material includes at least one of lithium cobalt oxide (LCO), lithium nickel manganese cobalt ternary material (NCM), lithium iron phosphate, lithium manganese iron phosphate, and lithium manganate. In some embodiments, when the electrochemical device adopts LCO and NCM systems, further electrochemical performance can be obtained by using the electrolyte additives provided in the present application.

正极导电剂用于为正极提供导电性，可改善正极导电率。正极导电剂是本领域公知的可被用作正极活性物质层的导电材料。正极导电剂可以选自任何导电的材料，只要它不引起化学变化即可。在一些实施例中，正极导电剂包含碳基材料(例如天然石墨、人造石墨、炭黑、乙炔黑、科琴黑、碳纤维)、金属基材料(例如包括铜、镍、铝、银等的金属粉或金属纤维)、导电聚合物(例如聚亚苯基衍生物)中的至少一种。The positive electrode conductive agent is used to provide conductivity for the positive electrode, which can improve the conductivity of the positive electrode. The positive electrode conductive agent is a conductive material known in the art that can be used as the positive electrode active material layer. The positive electrode conductive agent may be selected from any conductive material as long as it does not cause chemical changes. In some embodiments, the positive conductive agent comprises carbon-based materials (eg, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber), metal-based materials (eg, metals including copper, nickel, aluminum, silver, etc.) powder or metal fibers), conductive polymers (such as polyphenylene derivatives) at least one.

正极粘结剂是本领域公知的可被用作正极活性物质层的粘结剂。正极粘结剂可以改善正极活性物质颗粒彼此之间以及正极活性物质颗粒与正极集流体之间的粘结性能。在一些实施例中，正极粘结剂包含聚乙烯醇、羧甲基纤维素、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙中的至少一种。The positive electrode binder is known in the art and can be used as a binder for the positive electrode active material layer. The positive electrode binder can improve the bonding performance between the positive electrode active material particles and between the positive electrode active material particles and the positive electrode current collector. In some embodiments, the positive binder comprises polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyvinyl Ethoxylated polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin, nylon at least one of.

正极集流体为金属，在一些实施例中，金属例如但不限于铝箔。The positive current collector is a metal, in some embodiments, a metal such as, but not limited to, aluminum foil.

在一些实施例中，正极片的结构为本领域技术公知的可被用于电化学装置的正极片的结构。In some embodiments, the structure of the positive electrode sheet is known in the art as the structure of the positive electrode sheet that can be used in an electrochemical device.

在一些实施例中，正极片的制备方法是本领域技术公知的可被用于电化学装置的正极片的制备方法。在一些实施例中，在正极浆料的制备中，通常加入正极活性物质、粘结剂，并根据需要加入导电材料和增稠剂后溶解或分散于溶剂中制成正极浆料。溶剂在干燥过程中挥发去除。溶剂是本领域公知的可被用作正极活性物质层的溶剂，溶剂例如但不限于N-甲基吡咯烷酮(NMP)。In some embodiments, the preparation method of the positive electrode sheet is known in the art and can be used for the preparation of the positive electrode sheet of the electrochemical device. In some embodiments, in the preparation of the positive electrode slurry, a positive electrode active material, a binder, and a conductive material and a thickener are added as required, and then the positive electrode slurry is dissolved or dispersed in a solvent. The solvent is evaporated and removed during the drying process. The solvent is known in the art and can be used as the positive electrode active material layer, such as but not limited to N-methylpyrrolidone (NMP).

<负极片><Negative electrode>

负极片是本领域技术公知的可被用于电化学装置的负极片。在一些实施例中，负极片包含负极集流体以及设置在负极集流体上的负极活性物质层。在一些实施例中，负极活性物质层可包含负极活性物质、负极导电剂以及负极粘结剂。The negative electrode sheet is a negative electrode sheet known in the art that can be used in an electrochemical device. In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector. In some embodiments, the negative electrode active material layer may include a negative electrode active material, a negative electrode conductive agent, and a negative electrode binder.

在一些实施例中，负极活性物质包含锂金属、锂金属合金、过渡金属氧化物、碳材料、硅基材料中的至少一种。In some embodiments, the negative active material includes at least one of lithium metal, lithium metal alloy, transition metal oxide, carbon material, and silicon-based material.

在一些实施例中，负极粘结剂可以包含各种聚合物粘合剂。在一些实施例中，负极粘合剂包含二氟乙烯-六氟丙烯共聚物(PVDF-co-HFP)、聚偏二氟乙烯、聚丙烯腈、聚甲基丙烯酸甲酯、聚乙烯醇、羧甲基纤维素、羟丙基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙中的至少一种。In some embodiments, the anode binder may include various polymeric binders. In some embodiments, the negative electrode binder comprises vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxylate Methyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyethylene, poly At least one of propylene, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin and nylon.

在一些实施例中，负极活性物质层还包含负极导电剂。负极导电剂用于为负极提供导电性，可改善负极导电率。负极导电剂是本领域公知的可被用作负极活性物质层的导电材料。负极导电剂可以选自任何导电的材料，只要它不引起化学变化即可。In some embodiments, the negative electrode active material layer further includes a negative electrode conductive agent. The negative electrode conductive agent is used to provide conductivity for the negative electrode and can improve the conductivity of the negative electrode. The negative electrode conductive agent is a conductive material known in the art that can be used as the negative electrode active material layer. The negative electrode conductive agent may be selected from any conductive material as long as it does not cause chemical changes.

在一些实施例中，负极片的结构为本领域技术公知的可被用于电化学装置的负极片的结构。In some embodiments, the structure of the negative electrode sheet is known in the art as the structure of the negative electrode sheet that can be used in an electrochemical device.

在一些实施例中，负极片的制备方法是本领域技术公知的可被用于电化学装置的负极片的制备方法。在一些实施例中，在负极浆料的制备中，通常加入负极活性物质、粘合剂，并根据需要加入导电材料和增稠剂后溶解或分散于溶剂中制成负极浆料。溶剂在干燥过程中挥发去除。溶剂是本领域公知的可被用作负极活性物质层的溶剂，溶剂例如但不限于水。增稠剂是本领域公知的可被用作负极活性物质层的增稠剂，增稠剂例如但不限于羧甲基纤维素钠。In some embodiments, the preparation method of the negative electrode sheet is known in the art for the preparation method of the negative electrode sheet that can be used in an electrochemical device. In some embodiments, in the preparation of negative electrode slurry, negative electrode active material and binder are usually added, and conductive material and thickener are added as required, and then dissolved or dispersed in a solvent to prepare negative electrode slurry. The solvent is evaporated and removed during the drying process. The solvent is known in the art and can be used as the negative electrode active material layer, and the solvent is, for example, but not limited to, water. Thickeners are known in the art and can be used as a thickener for the negative active material layer, such as, but not limited to, sodium carboxymethylcellulose.

<隔离膜><Isolation film>

在一些实施例中，本申请的电化学装置包含隔离膜。隔离膜是本领域技术公知的可被用于电化学装置的隔离膜，例如但不限于聚烯烃类多孔膜。在一些实施例中，聚烯烃类多孔膜的基材包含聚乙烯(PE)、乙烯-丙烯共聚物、聚丙烯(PP)、乙烯-丁烯共聚物、乙烯-己烯共聚物、乙烯-甲基丙烯酸甲酯共聚物中的一种或几种组成的单层或多层。In some embodiments, the electrochemical devices of the present application include a separator. The separator is a separator known in the art that can be used in electrochemical devices, such as, but not limited to, a polyolefin-based porous membrane. In some embodiments, the base material of the polyolefin-based porous film comprises polyethylene (PE), ethylene-propylene copolymer, polypropylene (PP), ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-methyl Monolayer or multi-layer composed of one or more of methyl acrylate copolymers.

本申请对隔离膜的形态和厚度没有特别的限制。The present application has no particular restrictions on the shape and thickness of the separator.

隔离膜的制备方法是本领域技术公知的可被用于电化学装置的隔离膜的制备方法，例如：将勃姆石与聚丙烯酸酯混合并将其溶入到去离子水中以形成涂层浆料，随后采用微凹涂布法将所述涂层浆料均匀涂布到多孔基材的两个表面上，经过干燥处理以获得所需的隔离膜。The preparation method of the separator is well known in the art and can be used for the preparation of the separator for electrochemical devices, for example: mixing boehmite with polyacrylate and dissolving it in deionized water to form a coating slurry Then, the coating slurry is uniformly coated on both surfaces of the porous substrate by a gravure coating method, and the desired separator is obtained after drying treatment.

在一些实施例中，本申请电化学装置的充电截止电压为4.4至4.8V。In some embodiments, the charge cutoff voltage of the electrochemical device of the present application is 4.4 to 4.8V.

[电子装置][electronic device]

本申请的电子装置可以是任何电子装置，例如但不限于笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池、锂离子电容器。注意的是，本申请的电化学装置除了适用于上述列举的电子装置外，还适用于储能电站、海运运载工具、空运运载工具。空运运载装置包含在大气层内的空运运载装置和大气层外的空运运载装置。The electronic device of the present application can be any electronic device, such as but not limited to notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headphone, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large storage batteries for household use, and lithium-ion capacitors. It should be noted that the electrochemical device of the present application is not only applicable to the electronic devices listed above, but also applicable to energy storage power stations, marine vehicles, and air vehicles. Airborne vehicles include airborne vehicles within the atmosphere and airborne vehicles outside the atmosphere.

在一些实施例中，电子装置包含本申请所述的电化学装置。In some embodiments, the electronic device comprises an electrochemical device as described herein.

下面结合实施例，进一步阐述本申请。应理解，这些实施例仅用于说明本申请而不用于限制本申请的范围。在本申请的下述具体实施例中，仅示出电池为锂离子电池的实施例，但本申请不限于此。在下述实施例、对比例中，所使用到的试剂、材料等如没有特殊的说明，均可商购获得或合成获得。The present application will be further described below with reference to the embodiments. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. In the following specific embodiments of the present application, only an embodiment in which the battery is a lithium ion battery is shown, but the present application is not limited thereto. In the following examples and comparative examples, the reagents, materials, etc. used can be obtained commercially or synthetically unless otherwise specified.

实施例和对比例的锂离子电池均按照下述方法制备。The lithium ion batteries of the examples and comparative examples were prepared according to the following methods.

1)正极片的制备1) Preparation of positive electrode sheet

将正极活性材料钴酸锂(LiCoO ₂)、导电剂Super P、粘结剂聚偏二氟乙烯按照重量比97.9:0.4:1.7进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌均匀，获得正极浆料；将正极浆料均匀涂覆于正极集流体铝箔上；将铝箔烘干，然后经过冷压、裁片、分切后，在真空条件下干燥，得到正极片。 The positive active material lithium cobalt oxide (LiCoO ₂ ), the conductive agent Super P, and the binder polyvinylidene fluoride are mixed according to the weight ratio of 97.9:0.4:1.7, and N-methylpyrrolidone (NMP) is added. The positive electrode slurry is uniformly coated on the aluminum foil of the positive electrode current collector, and the aluminum foil is dried, and then subjected to cold pressing, cutting, slitting, and drying under vacuum conditions to obtain the positive electrode sheet.

2)负极片的制备2) Preparation of negative electrode sheet

将负极活性材料人造石墨、增稠剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)按照重量比97:1:2进行混合，加入去离子水，在真空搅拌机作用下获得负极浆料；将负极浆料均匀涂覆在负极集流体铜箔上；将铜箔烘干，然后经过冷压、裁片、分切后，在真空条件下干燥，得到负极片。The negative active material artificial graphite, thickener sodium carboxymethyl cellulose (CMC), and binder styrene-butadiene rubber (SBR) were mixed according to the weight ratio of 97:1:2, deionized water was added, and under the action of a vacuum mixer A negative electrode slurry is obtained; the negative electrode slurry is uniformly coated on the negative electrode current collector copper foil; the copper foil is dried, and then subjected to cold pressing, cutting, slitting, and drying under vacuum conditions to obtain a negative electrode sheet.

3)隔离膜的制备3) Preparation of separator

将勃姆石与聚丙烯酸酯混合并将其溶入到去离子水中以形成涂层浆料。随后采用微凹涂布法将所述涂层浆料均匀涂布到聚乙烯多孔基材的两个表面上，经过干燥处理以获得所需的隔离膜。The boehmite and polyacrylate were mixed and dissolved in deionized water to form a coating slurry. Then, the coating slurry is uniformly coated on both surfaces of the polyethylene porous substrate by a gravure coating method, and the desired separator is obtained by drying treatment.

4)电解液的制备4) Preparation of electrolyte

在干燥的氩气气氛手套箱中，采用重量比EC(碳酸乙烯酯):PC(碳酸丙烯酯):DEC(碳酸二乙酯)＝2:2:6作为基础溶剂，并参照表1至表5含量加入各组分，溶解并充分搅拌后加入锂盐LiPF ₆，混合均匀后获得LiPF ₆的含量为1mol/L的电解液。其中，表中各组分含量均为基于电解液的重量计算得到的重量百分数。 In a dry argon atmosphere glove box, use the weight ratio EC (ethylene carbonate):PC (propylene carbonate):DEC (diethyl carbonate)=2:2:6 as the base solvent, and refer to Tables 1 to 1 5 Contents: Add each component, dissolve and fully stir and then add lithium salt LiPF ₆ , and mix uniformly to obtain an electrolyte solution with a LiPF ₆ content of 1 mol/L. Wherein, the content of each component in the table is the weight percentage calculated based on the weight of the electrolyte.

5)锂离子电池的制备5) Preparation of lithium-ion battery

将正极片、隔离膜、负极片按顺序叠好，使隔离膜处于正、负极片之间起到隔离的作用，然后卷绕得到裸电芯；焊接极耳后将裸电芯置于外包装箔铝塑膜中，将上述制备好的电解液注入到干燥后的裸电芯中，经过真空封装、静置、化成、整形、容量测试等工序，获得软包锂离子电池。Stack the positive electrode sheet, the separator film and the negative electrode sheet in order, so that the separator film is placed between the positive and negative electrode sheets for isolation, and then coil to obtain a bare cell; after welding the tabs, place the bare cell in the outer package In the foil-aluminum-plastic film, the electrolyte prepared above is injected into the dried bare cell, and the soft-pack lithium-ion battery is obtained through the processes of vacuum packaging, standing, forming, shaping, and capacity testing.

接下来说明锂离子电池的性能测试过程。Next, the performance testing process of the lithium-ion battery is described.

(1)锂离子电池的高温循环性能测试(1) High temperature cycle performance test of lithium ion battery

将锂离子电池置于45℃恒温箱中，静置30min，使锂离子电池达到恒温。将达到恒温的锂离子电池以1C恒流充电至电压为4.45V，然后以4.45V恒压充电至电流为0.025C，接着以1C恒流放电至电压为3.0V，此为一个充放电循环，记录首次放电的容量Q ₁。按上述方式充放电循环400次，停止测试，记录循环后的放电容量Q ₂。通过下式可得到高温循环后的容量保持率：高温循环容量保持率＝循环后放电容量Q ₂/首次放电容量Q ₁×100％。 Place the lithium-ion battery in a 45°C incubator for 30 minutes to make the lithium-ion battery reach a constant temperature. The lithium-ion battery that has reached a constant temperature is charged with a constant current of 1C to a voltage of 4.45V, then charged with a constant voltage of 4.45V to a current of 0.025C, and then discharged with a constant current of 1C to a voltage of 3.0V. This is a charge-discharge cycle. The capacity Q ₁ of the first discharge is recorded. Charge and discharge cycle 400 times in the above manner, stop the test, and record the discharge capacity Q ₂ after the cycle. The capacity retention rate after high temperature cycle can be obtained by the following formula: high temperature cycle capacity retention rate=post-cycle discharge capacity Q ₂ /first discharge capacity Q ₁ ×100%.

(2)锂离子电池的循环阻抗增长率测试(2) Cyclic impedance growth rate test of lithium-ion batteries

将锂离子电池置于25℃恒温箱，静置1小时。将锂离子电池以1C恒流充电至4.45V，恒压充电至电流为0.025C，静置120min，然后以0.1C直流充电10秒，以1C直流充电360秒，然后记录该锂离子电池在80％荷电状态(SOC)时的直流阻抗。按(1)锂离子电池的高温循环性能测试中标准，对该电池进行充放电循环400次，然后以上述测量方法测量并记录该锂离子电池在80％荷电状态(SOC)时的直流阻抗。通过下式分别计算该锂离子电池的直流阻抗：直流阻抗＝(0.1C放电终止电压-1C放电终止电压)/(0.1C放电终止电流-1C放电终止电流)。通过下式计算该锂离子电池的循环阻抗增长率：循环阻抗增长率＝(循环后的锂离子电池的直流阻抗-循环前的锂离子电池的直流阻抗)/循环前的锂离子电池的直流阻抗×100％。The lithium-ion battery was placed in a 25°C incubator for 1 hour. Charge the lithium-ion battery to 4.45V with a constant current of 1C, charge it with a constant voltage to a current of 0.025C, let it stand for 120 minutes, then charge it with 0.1C DC for 10 seconds, and charge it with 1C DC for 360 seconds, and then record the lithium-ion battery at 80 DC impedance at % state of charge (SOC). According to (1) the standard in the high temperature cycle performance test of lithium ion battery, the battery is charged and discharged for 400 times, and then the DC impedance of the lithium ion battery at 80% state of charge (SOC) is measured and recorded by the above measurement method. . The DC impedance of the lithium ion battery was calculated respectively by the following formula: DC impedance=(0.1C discharge end voltage-1C discharge end voltage)/(0.1C discharge end current-1C discharge end current). The cycle impedance growth rate of the lithium ion battery is calculated by the following formula: Cycle impedance growth rate = (DC impedance of the lithium ion battery after the cycle - DC impedance of the lithium ion battery before the cycle)/DC impedance of the lithium ion battery before the cycle ×100%.

实施例和对比例的锂离子电池的相关参数以及锂离子电池的性能测试结果如表1至表5所示。The relevant parameters of the lithium ion batteries of the examples and comparative examples and the performance test results of the lithium ion batteries are shown in Tables 1 to 5.

其中，表1展示了式(I)表示的化合物对锂离子电池的高温循环性能和循环阻抗增长率的影响。Among them, Table 1 shows the effect of the compound represented by formula (I) on the high temperature cycle performance and cycle resistance growth rate of the lithium ion battery.

表2展示了电解液中的式(I)表示的化合物的含量对锂离子电池的高温循环性能和循环阻抗增长率的影响。Table 2 shows the effect of the content of the compound represented by the formula (I) in the electrolyte on the high temperature cycle performance and cycle resistance growth rate of the lithium ion battery.

表3展示了添加剂B与式(I)表示的化合物的含量关系对锂离子电池的高温循环性能和循环阻抗增长率的影响。Table 3 shows the effect of the content relationship between additive B and the compound represented by formula (I) on the high temperature cycle performance and cycle resistance growth rate of lithium ion batteries.

表4展示了羧酸酯溶剂与式(I)表示的化合物的含量关系对锂离子电池的高温循环性能和循环阻抗增长率的影响。Table 4 shows the effect of the content relationship between the carboxylate solvent and the compound represented by formula (I) on the high temperature cycle performance and cycle resistance growth rate of the lithium ion battery.

表5展示了添加剂C与式(I)表示的化合物的组合对锂离子电池的高温循环性能和循环阻抗增长率的影响。Table 5 shows the effect of the combination of additive C and the compound represented by formula (I) on the high temperature cycle performance and cycle resistance growth rate of lithium ion batteries.

表1Table 1

注：“/”表示未添加该组分的物质。Note: "/" indicates the substance without this component added.

表1的性能测试结果表明，在电解液中加入式(I)表示的化合物可显著提升锂离子电池的高温循环性能和显著降低其循环阻抗增长。和对比例1-2相比，式(I)表示的化合物较单一糠醛化合物具有更明显的高温循环改善效果，这是由于糠醛上支接的含有氮、硫、氧原子的杂环，可以丰富SEI的LiN、Li _xS及Li _xSO _y等无机组成，所以杂环和糠醛结合的化合物较单一糠醛生成的烷氧基锂有机成分，具有更优的高电压稳定性。从实施例1-1至实施例1-9可知，式(I-4)对高温循环容量保持率的提升和阻抗增长的降低有相对较好的效果，其次为式(I-2)、式(I-3)这可能是由于支链杂环基团不宜过大，否则空间位阻较大，影响其成膜的致密稳定性。 The performance test results in Table 1 show that adding the compound represented by formula (I) to the electrolyte can significantly improve the high-temperature cycle performance of the lithium-ion battery and significantly reduce the growth of its cycle impedance. Compared with Comparative Examples 1-2, the compound represented by formula (I) has a more obvious high-temperature cycle improvement effect than a single furfural compound. This is because the heterocycles containing nitrogen, sulfur and oxygen atoms branched on furfural can enrich SEI is composed of inorganic components such as _LiN , _LixS and _LixSOy , so the compound of heterocycle and furfural combined has better high voltage stability than the organic component of alkoxide lithium generated by single furfural. From Example 1-1 to Example 1-9, it can be seen that formula (I-4) has relatively good effects on the improvement of high temperature cycle capacity retention rate and the reduction of impedance growth, followed by formula (I-2), formula (I-3) This may be due to the fact that the branched heterocyclic group should not be too large, otherwise the steric hindrance will be large, which will affect the compactness and stability of its film formation.

表2Table 2

表2的性能测试结果表明，当式(I)表示的化合物在电解液中的含量在0.02％至7％的范围内时，有助于进一步提升锂离子电池的高温循环性能并降低其循环阻抗增长率。当式(I)表示的化合物在电解液中的含量在0.5％至3％的范围内时，其对锂离子电池的高温循环性能和循环阻抗增长率的改善尤为明显。当式(I)所示的化合物的含量低于0.02％时，其对锂电池在高电压下的高温循环性能改善体现不明显；当式(I)所示的化合物的含量高于7％时，电解液中的该化合物过多，导致界面膜阻抗较大，造成不可逆锂析出，阻碍电解液的离子传输通道，加速电池容量的衰减。The performance test results in Table 2 show that when the content of the compound represented by formula (I) in the electrolyte is in the range of 0.02% to 7%, it is helpful to further improve the high-temperature cycle performance of lithium-ion batteries and reduce their cycle resistance. growth rate. When the content of the compound represented by formula (I) in the electrolyte is in the range of 0.5% to 3%, the improvement of high temperature cycle performance and cycle resistance growth rate of lithium ion batteries is particularly remarkable. When the content of the compound represented by the formula (I) is less than 0.02%, the improvement of the high temperature cycle performance of the lithium battery under high voltage is not obvious; when the content of the compound represented by the formula (I) is higher than 7% , the compound in the electrolyte is too much, resulting in a large interface film impedance, resulting in irreversible lithium precipitation, hindering the ion transport channel of the electrolyte, and accelerating the attenuation of the battery capacity.

表3table 3

表3的性能测试结果表明，当电解液包含添加剂B(氟代碳酸乙烯酯(FEC)、碳酸亚乙烯酯(VC)中的至少一种)且第一添加剂的含量m％与式(I)表示的化合物的含量n％满足-1≤k+m-n≤12时，锂离子电池具有显著提升的高温循环性能并显著降低的循环阻抗增长率。适量的FEC及VC，配合式(I)化合物，能够进一步丰富SEI膜中LiF的构成。所以FEC及VC与式(I)化合物在适当含量下的组合使用，对锂离子电池高温循环中负极的稳定性具有显著的改善效果，但FEC及VC的相对含量较高时，对锂离子电池的高温循环性能造成不利影响，这可能是由于FEC、VC在高电压下容易氧化分解产气，其过高的相对添加量，使得该添加剂组合物无法形成对极片具有良好保护效果且具有良好电解质离子通道的组合电解质界面。FEC、VC和式(I)表示的化合物的联合使用可以进一步增强电化学装置在高电压下在负极的成膜稳定性，通过协同作用抑制阻抗增长，改善锂离子电池在高电压下的循环性能。The performance test results in Table 3 show that when the electrolyte contains additive B (at least one of fluoroethylene carbonate (FEC) and vinylene carbonate (VC)) and the content of the first additive m% is the same as the formula (I) When the content n% of the indicated compound satisfies -1≤k+m-n≤12, the lithium ion battery has significantly improved high temperature cycle performance and significantly reduced cycle resistance growth rate. An appropriate amount of FEC and VC, in combination with the compound of formula (I), can further enrich the composition of LiF in the SEI film. Therefore, the combined use of FEC and VC and the compound of formula (I) at an appropriate content can significantly improve the stability of the negative electrode in high-temperature cycling of lithium-ion batteries, but when the relative content of FEC and VC is high, the lithium-ion battery This may be due to the fact that FEC and VC are easily oxidized and decomposed under high voltage to produce gas, and the excessively high relative addition amount makes the additive composition unable to form a good protective effect on the pole piece and has a good Combined electrolyte interface for electrolyte ion channels. The combined use of FEC, VC and the compound represented by formula (I) can further enhance the film formation stability of electrochemical devices at high voltages, suppress impedance growth through synergistic effects, and improve the cycling performance of lithium-ion batteries at high voltages .

表4Table 4

表4的性能测试结果表明，当电解液包含羧酸酯时，有助于进一步提升锂离子电池的高温循环性能并降低其循环阻抗增长率。当羧酸酯含量a％与式(I)表示的化合物含量n％满足0.05≤n/a≤0.1时，其对锂离子电池的高温循环性能和循环阻抗增长率的改善尤为明显。引入羧酸酯，能够有效的降低电解液粘度，利于锂离子传输，降低成膜阻抗，但过多羧酸酯在高电压下容易氧化分解，反而不利于维持循环中锂离子传输。通过和式(I)化合物在一定含量比例下的联用，可以通过协同作用进一步抑制阻抗增长，改善锂离子电池在高电压下的循环性能。The performance test results in Table 4 show that when the electrolyte contains carboxylate, it is helpful to further improve the high temperature cycle performance of the lithium ion battery and reduce its cycle impedance growth rate. When the carboxylate content a% and the compound content n% represented by formula (I) satisfy 0.05≤n/a≤0.1, the high temperature cycle performance and cycle resistance growth rate of lithium ion batteries are improved particularly significantly. The introduction of carboxylate can effectively reduce the viscosity of the electrolyte, which is beneficial to the transport of lithium ions and reduces the film-forming resistance. However, too much carboxylate is easily oxidized and decomposed under high voltage, which is not conducive to maintaining lithium ion transport in the cycle. By combining with the compound of formula (I) at a certain content ratio, the increase of impedance can be further suppressed through synergistic effect, and the cycle performance of the lithium ion battery under high voltage can be improved.

表5table 5

表5的性能测试结果表明，当电解液包含腈类化合物时，有助于进一步提升锂离子电池的高温循环性能并降低其循环阻抗增长率，这是因为腈类化合物可以在正极表面形成有机保护层，在正极表面的有机分子可以很好地将电解液中易氧化组分与正极表面隔开，一方面降低了高电压下正极表面对电解液的氧化作用，另一方面减少了正极过渡金属氧化物过度释氧带来的结构破坏。当腈类含量在0.5％至5％时，其对锂离子电池的高温循环性能和循环阻抗增长率的改善尤为明显。The performance test results in Table 5 show that when the electrolyte contains nitrile compounds, it helps to further improve the high-temperature cycle performance of lithium-ion batteries and reduce its cycle resistance growth rate, because nitrile compounds can form organic protection on the surface of the positive electrode The organic molecules on the surface of the positive electrode can well separate the easily oxidizable components in the electrolyte from the surface of the positive electrode. Structural damage caused by excessive oxygen release from oxides. When the content of nitrile is between 0.5% and 5%, the improvement of high temperature cycle performance and cycle resistance growth rate of lithium-ion batteries is particularly obvious.

通过实施例5-20、实施例5-24对比实施例2-4、实施例5-22可知，当电解液进一步添加适量磺酸酯类化合物时，对锂离子电池的高温循环性和阻抗增长率有显著的改善作用。From Example 5-20, Example 5-24, Example 2-4, Example 5-22, it can be seen that when an appropriate amount of sulfonate compound is further added to the electrolyte, the high temperature cyclability and impedance of the lithium ion battery increase rate has been significantly improved.

通过实施例5-20至实施例5-24，与实施例2-4、实施例3-13、实施例3-14及实施例5-18的对比可知，在电解液中包括式(I)化合物的基础上，通过氟代碳酸乙烯酯、碳酸亚乙烯酯、羧酸酯、腈类化合物中或含硫氧双键化合物中的一种或多种在合适范围内的组合使用，可以改善高电压体系下锂离子电池正负极电解质界面的稳定性，从而改善锂离子电池的高温循环性能，并抑制阻抗增长。By comparing Examples 5-20 to 5-24 with Examples 2-4, Example 3-13, Example 3-14 and Example 5-18, it can be known that formula (I) is included in the electrolyte solution. On the basis of the compound, through the combined use of one or more of fluoroethylene carbonate, vinylene carbonate, carboxylate, nitrile compounds or compounds containing sulfur-oxygen double bonds within a suitable range, the high performance can be improved. The stability of the anode and cathode electrolyte interfaces of lithium-ion batteries under the voltage system, thereby improving the high-temperature cycling performance of lithium-ion batteries and suppressing impedance growth.

以上所述，仅是本申请的示例，并非对本申请做任何形式的限制，虽然本申请以较佳实施例揭示如上，然而并非用以限制本公开，任何熟悉本专业的技术人员，在不脱离本申请技术方案的范围内，利用上述揭示的技术内容做出些许的变动或修饰均等同于等效实施案例，均在本申请技术方案的范围内。The above is only an example of the present application, and does not limit the present application in any form. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present disclosure. Within the scope of the technical solution of the present application, any changes or modifications made by using the technical content disclosed above are equivalent to equivalent implementation cases, and are all within the scope of the technical solution of the present application.

Claims

一种电解液，其中，包括式(I)表示的化合物，A kind of electrolyte, wherein, comprises the compound represented by formula (I),

在式(I)中，R ₁₁选自共价键、氧、硫、C ₁-C ₁₀亚烃基、C ₁-C ₅亚烷氧基或C ₁-C ₅亚烷硫基，所述亚烃基包括亚烷基、亚烯基或亚芳基； In formula (I), R ₁₁ is selected from covalent bonds, oxygen, sulfur, C ₁ -C ₁₀ alkylene, C ₁ -C ₅ alkyleneoxy or C ₁ -C ₅ alkylenethio, the Hydrocarbyl includes alkylene, alkenylene or arylene;

R ₁₂选自共价键、C ₁-C ₁₀亚烃基或C ₁-C ₁₀亚烃基磺酰基，所述亚烃基包括亚烷基、亚烯基或亚芳基； R ₁₂ is selected from a covalent bond, a C ₁ -C ₁₀ hydrocarbylene group or a C ₁ -C ₁₀ hydrocarbylene sulfonyl group, the hydrocarbylene group includes an alkylene group, an alkenylene group or an arylene group;

X选自经取代或未经取代的C ₁-C ₁₀的含氧、氮或硫原子中至少一种的杂环基；经取代时，取代基包括烃基、氰基或卤素，所述烃基包括烷基、烯基或炔基；所述杂环包括环醚、吗啉、吡啶、三氮唑、呋喃、吡喃、哌啶、吡咯、吡唑、吡嗪、哒嗪或咪唑中的至少一种。 X is selected from substituted or unsubstituted C ₁ -C ₁₀ heterocyclic groups containing at least one of oxygen, nitrogen or sulfur atoms; when substituted, the substituents include hydrocarbyl, cyano or halogen, and the hydrocarbyl includes Alkyl, alkenyl or alkynyl; the heterocycle includes at least one of cyclic ether, morpholine, pyridine, triazole, furan, pyran, piperidine, pyrrole, pyrazole, pyrazine, pyridazine or imidazole kind.
根据权利要求1所述的电解液，其中，所述式(I)表示的化合物包括式(I-1)至式(I-7)表示的化合物中的至少一种；The electrolyte solution according to claim 1, wherein the compound represented by the formula (I) includes at least one of the compounds represented by the formula (I-1) to the formula (I-7);
根据权利要求1所述的电解液，其中，基于所述电解液的重量，所述式(I)表示的化合物的含量为n％，0.02≤n≤7。The electrolyte solution according to claim 1, wherein, based on the weight of the electrolyte solution, the content of the compound represented by the formula (I) is n%, and 0.02≤n≤7.
根据权利要求3所述的电解液，其中，电解液还包括氟代碳酸乙烯酯、碳酸亚乙烯酯中的至少一种；The electrolyte according to claim 3, wherein the electrolyte further comprises at least one of fluoroethylene carbonate and vinylene carbonate;

基于所述电解液的重量，氟代碳酸乙烯酯的含量为k％，碳酸亚乙烯酯的含量为m％，其中，k≥0，m≥0，k+m＞0，且k、m和n满足-1≤k+m-n≤12。Based on the weight of the electrolyte, the content of fluoroethylene carbonate is k%, and the content of vinylene carbonate is m%, wherein k≥0, m≥0, k+m>0, and k, m and n satisfies -1≤k+m-n≤12.
根据权利要求3所述电解液，其中，所述电解液还包括羧酸酯；基于所述电解液的重量，所述羧酸酯的含量为a％，5≤a≤30，且a和n满足关系：0.0005≤n/a≤0.7。The electrolyte according to claim 3, wherein the electrolyte further comprises carboxylate; based on the weight of the electrolyte, the content of the carboxylate is a%, 5≤a≤30, and a and n The relationship is satisfied: 0.0005≤n/a≤0.7.
根据权利要求5所述电解液，其中，所述羧酸酯包括乙酸乙酯、乙酸丙酯、乙酸丁酯、丙酸乙酯、丙酸丙酯、丙酸丁酯中的至少一种。The electrolyte according to claim 5, wherein the carboxylic acid ester comprises at least one of ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, and butyl propionate.
根据权利要求1-6中任一项所述电解液，其中，所述电解液还包括1,3-丙烷磺内酯、2,4-丁磺内酯或腈类化合物中的至少一种。The electrolyte solution according to any one of claims 1-6, wherein the electrolyte solution further comprises at least one of 1,3-propane sultone, 2,4-butanesultone or nitrile compounds.
根据权利要求7所述电解液，其中，所述腈类化合物包括式(Ⅱ)至式(Ⅴ)表示的化合物中的至少一种；The electrolyte according to claim 7, wherein the nitrile compound comprises at least one of the compounds represented by formula (II) to formula (V);

N≡C-R ₂₁-C≡N 式(Ⅱ) N≡CR ₂₁ -C≡N Formula (Ⅱ)

其中，R ₂₁选自经取代或未经取代的C ₁-C ₁₂亚烷基、经取代或未经取代的C ₁-C ₁₂亚烷氧基； wherein, R ₂₁ is selected from substituted or unsubstituted C ₁ -C ₁₂ alkylene, substituted or unsubstituted C ₁ -C ₁₂ alkyleneoxy;

R ₃₁、R ₃₂各自独立地选自共价键、经取代或未经取代的C ₁-C ₁₂亚烷基； R ₃₁ , R ₃₂ are each independently selected from covalent bonds, substituted or unsubstituted C ₁ -C ₁₂ alkylene;

R ₄₁、R ₄₂、R ₄₃各自独立地选自共价键、经取代或经未取代的C ₁-C ₁₂亚烷基、经取代或未经取代的C ₁-C ₁₂亚烷氧基； R ₄₁ , R ₄₂ , R ₄₃ are each independently selected from covalent bonds, substituted or unsubstituted C ₁ -C ₁₂ alkylene, substituted or unsubstituted C ₁ -C ₁₂ alkyleneoxy;

R ₅₁选自经取代或经未经取代的C ₁-C ₁₂亚烷基、经取代或未经取代的C ₂-C ₁₂亚烯基、经取代或未经取代的C ₆-C ₁₂亚芳基、经取代或未经取代的C ₃-C ₁₂亚环基； R ₅₁ is selected from substituted or unsubstituted C ₁ -C ₁₂ alkylene, substituted or unsubstituted C ₂ -C ₁₂ alkenylene, substituted or unsubstituted C ₆ -C ₁₂ alkylene Aryl, substituted or unsubstituted C ₃ -C ₁₂ cyclylene;

其中经取代时，取代基为卤素。Wherein, when substituted, the substituent is halogen.
根据权利要求8所述电解液，其中，所述腈类化合物包括以下化合物中的至少一种；The electrolyte according to claim 8, wherein the nitrile compound comprises at least one of the following compounds;
一种电化学装置，包括正极、负极、隔离膜以及根据权利要求1-9中任一项所述的电解液。An electrochemical device, comprising a positive electrode, a negative electrode, a separator, and the electrolyte according to any one of claims 1-9.
根据权利要求10所述的电化学装置，其中，所述电化学装置的充电截止电压为4.4至4.8V。The electrochemical device of claim 10, wherein a charge cut-off voltage of the electrochemical device is 4.4 to 4.8V.
一种电子装置，包括根据权利要求10-11所述的电化学装置。An electronic device comprising an electrochemical device according to claims 10-11.