WO2023123030A1

WO2023123030A1 - Electrochemical device and electronic device

Info

Publication number: WO2023123030A1
Application number: PCT/CN2021/142400
Authority: WO
Inventors: 张青文; 王可飞
Original assignee: 宁德新能源科技有限公司
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2023-07-06
Also published as: CN115380408A

Abstract

The present application relates to an electrochemical device and an electronic device. Specifically, the present application provides an electrochemical device, which comprises: a positive electrode, a negative electrode, and an electrolyte; the positive electrode comprises a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector, wherein the positive electrode active material layer comprises poly(amic acid), and the electrolyte comprises a difluorophosphite compound. The electrochemical device provided by the invention has improved float charge performance and safety.

Description

电化学装置和电子装置Electrochemical devices and electronic devices

技术领域technical field

本申请涉及储能领域，具体涉及一种电化学装置和电子装置，特别是锂离子电池。The present application relates to the field of energy storage, in particular to an electrochemical device and an electronic device, especially a lithium ion battery.

背景技术Background technique

近年来，随着智能手机、平板电脑和智能穿戴等电子产品的快速发展，考虑到电子产品的使用时长和工作环境的不同，人们对电化学装置(例如，锂离子电池)的性能提出了更高的要求，这体现在：较高的容量、合适的循环寿命、良好的高温性能、良好的高倍率放电性能、抗过充性能、浮充性能和安全性等。In recent years, with the rapid development of electronic products such as smartphones, tablet computers, and smart wearables, people have put forward more and more demands on the performance of electrochemical devices (such as lithium-ion batteries) considering the use time of electronic products and the different working environments. High requirements, which are reflected in: high capacity, suitable cycle life, good high temperature performance, good high rate discharge performance, anti-overcharge performance, floating charge performance and safety, etc.

虽然电池生产企业、原料供应商和科研院所围绕锂离子电池的性能改善做了大量工作，但现有方法仍然无法有效地提高锂离子电池的浮充性能并从根本上控制锂离子电池的热失控。Although battery manufacturers, raw material suppliers and scientific research institutes have done a lot of work to improve the performance of lithium-ion batteries, the existing methods are still unable to effectively improve the floating charge performance of lithium-ion batteries and fundamentally control the heat dissipation of lithium-ion batteries. out of control.

有鉴于此，确有必要提供一种具有改进的浮充性能和安全性的电化学装置和电子装置。In view of this, there is a need to provide an electrochemical device and an electronic device with improved float performance and safety.

发明内容Contents of the invention

本申请实施例通过提供一种具有改善的浮充性能和安全性的电化学装置和电子装置以在某种程度上解决存在于现有技术的问题。The embodiments of the present application solve the problems existing in the prior art to some extent by providing an electrochemical device and an electronic device with improved float charging performance and safety.

在本申请的一方面，本申请提供一种电化学装置，其包括：正极、负极和电解液，所述正极包括正极集流体和形成在所述正极集流体上的正极活性物质层，其中：所述正极活性物质层包括聚(酰胺酸)，并且所述电解液包括二氟亚磷酸酯化合物。In one aspect of the present application, the present application provides an electrochemical device, which includes: a positive electrode, a negative electrode and an electrolyte, the positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector, wherein: The positive electrode active material layer includes poly(amic acid), and the electrolytic solution includes a difluorophosphite compound.

根据本申请的实施例，基于所述正极活性物质层的重量，所述聚(酰胺酸)的含量为a％；基于所述电解液的重量，所述二氟亚磷酸酯化合物的含量为b％；且a和b满足：0.1≤a/b≤5。According to an embodiment of the present application, based on the weight of the positive electrode active material layer, the content of the poly(amic acid) is a%; based on the weight of the electrolyte, the content of the difluorophosphite compound is b %; and a and b satisfy: 0.1≤a/b≤5.

根据本申请的实施例，a的取值范围为0.5至5。According to the embodiment of the present application, a ranges from 0.5 to 5.

根据本申请的实施例，b的取值范围为0.1至5。According to the embodiment of the present application, the value of b ranges from 0.1 to 5.

根据本申请的实施例，所述聚(酰胺酸)包括式I化合物：According to an embodiment of the application, the poly(amic acid) includes a compound of formula I:

其中：in:

R选自C1-12烯基或C6-12芳环；R is selected from C1-12 alkenyl or C6-12 aromatic ring;

A选自单键、C1-12烯基或C6-12芳环；A is selected from single bond, C1-12 alkenyl or C6-12 aromatic ring;

n为5至20的整数。n is an integer of 5-20.

根据本申请的实施例，所述二氟亚磷酸酯化合物包括式II化合物：According to an embodiment of the present application, the difluorophosphite compound includes a compound of formula II:

A-OPF ₂(式II)， A-OPF ₂ (Formula II),

其中A为经取代或未经取代的C1-10烷基或C3-10环烷基；Wherein A is substituted or unsubstituted C1-10 alkyl or C3-10 cycloalkyl;

经取代时，取代基为卤素或氰基。When substituted, the substituent is halogen or cyano.

根据本申请的实施例，所述二氟亚磷酸酯化合物包括以下化合物中的至少一种：According to an embodiment of the present application, the difluorophosphite compound includes at least one of the following compounds:

根据本申请的实施例，所述电解液还包括含硫氧双键的化合物，所述含硫氧双键的化合物包括以下化合物中的至少一者：环状硫酸酯、链状硫酸酯、链状磺酸酯、环状磺酸酯、链状亚硫酸酯或环状亚硫酸酯或式III化合物：According to an embodiment of the present application, the electrolyte solution further includes a compound containing a sulfur-oxygen double bond, and the compound containing a sulfur-oxygen double bond includes at least one of the following compounds: cyclic sulfate, chain sulfate, chain Shaped sulfonate, cyclic sulfonate, chain sulfite or cyclic sulfite or compound of formula III:

其中：in:

W选自

W selected from

L选自单键或亚甲基；L is selected from a single bond or methylene;

m为1至4的整数；m is an integer from 1 to 4;

n为0至2的整数；且n is an integer from 0 to 2; and

p为0至6的整数。p is an integer of 0 to 6.

根据本申请的实施例，所述式III化合物选自以下中的至少一种：According to the embodiments of the present application, the compound of formula III is selected from at least one of the following:

根据本申请的实施例，基于所述电解液的重量，所述二氟亚磷酸酯化合物的含量为b％，所述含硫氧双键的化合物的含量为c％，b和c满足：1≤b+c≤8和0.4≤b/c≤5。According to an embodiment of the present application, based on the weight of the electrolyte, the content of the difluorophosphite compound is b%, the content of the compound containing sulfur and oxygen double bonds is c%, and b and c satisfy: 1 ≤b+c≤8 and 0.4≤b/c≤5.

根据本申请的实施例，基于所述电解液的重量，所述含硫氧双键的化合物的含量为c％，c的取值范围为0.1至8。According to an embodiment of the present application, based on the weight of the electrolyte, the content of the sulfur-oxygen double bond-containing compound is c%, and the value of c ranges from 0.1 to 8.

根据本申请的实施例，c的取值范围为0.1至1.5According to the embodiment of the present application, the value range of c is 0.1 to 1.5

在本申请的另一方面，本申请提供一种电子装置，其包括根据本申请的电化学装置。In another aspect of the present application, the present application provides an electronic device comprising the electrochemical device according to the present application.

本申请使用的包括聚(酰胺酸)的正极活性物质和包括二氟亚磷酸酯化合物的电解液的特定组合可改善正极活性物质层在热失控下的的界面稳定性，并且能够充分抑制电化学装置在高压高温下的浮充厚度增长，有效防止电池热失控引起的燃烧或***等安全问题。The specific combination of the positive electrode active material comprising poly(amic acid) and the electrolyte solution comprising difluorophosphite compound used in the present application can improve the interfacial stability of the positive electrode active material layer under thermal runaway, and can sufficiently inhibit electrochemical The floating charge thickness of the device increases under high pressure and high temperature, which can effectively prevent safety problems such as combustion or explosion caused by thermal runaway of the battery.

本申请实施例的额外层面及优点将部分地在后续说明中描述、显示、或是经由本申请实施例的实施而阐释。Additional aspects and advantages of the embodiments of the present application will be partially described, shown, or explained through the implementation of the embodiments of the present application in the subsequent description.

具体实施方式Detailed ways

本申请的实施例将会被详细的描示在下文中。本申请的实施例不应该被解释为对本申请的限制。Embodiments of the present application will be described in detail below. The examples of the present application should not be construed as limiting the present application.

除非另外明确指明，本文使用的下述术语具有下文指出的含义。Unless otherwise expressly indicated, the following terms used herein have the meanings indicated below.

在具体实施方式及权利要求书中，由术语“中的至少一者”连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。术语“中的至少一种”具有与术语“中的至少一者”相同的含义。In the detailed description and claims, a list of items linked by the term "at least one of" may mean any combination of the listed items. For example, if the items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if the items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements. The term "at least one of" has the same meaning as the term "at least one of".

术语“烷基”预期是具有1至20个碳原子的直链饱和烃结构。“烷基”还预期是具有3至20个碳原子的支链或环状烃结构。当指定具有具体碳数的烷基时，预期涵盖具有该碳数的所有几何异构体；因此，例如，“丁基”意思是包括正丁基、仲丁基、异丁基、叔丁基和环丁基；“丙基”包括正丙基、异丙基和环丙基。烷基实例包括，但不限于甲基、乙基、正丙基、异丙基、环丙基、正丁基、异丁基、仲丁基、叔丁基、环丁基、正戊基、异戊基、新戊基、环戊基、甲基环戊基、乙基环戊基、正己基、异己基、环己基、正庚基、辛基、环丙基、环丁基、降冰片基等。The term "alkyl" is intended to be a straight chain saturated hydrocarbon structure having from 1 to 20 carbon atoms. "Alkyl" is also contemplated as branched or cyclic hydrocarbon structures having from 3 to 20 carbon atoms. When an alkyl group having a specific number of carbons is specified, all geometric isomers having that number of carbons are intended to be encompassed; thus, for example, "butyl" is meant to include n-butyl, sec-butyl, iso-butyl, tert-butyl and cyclobutyl; "propyl" includes n-propyl, isopropyl and cyclopropyl. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, Isopentyl, neopentyl, cyclopentyl, methylcyclopentyl, ethylcyclopentyl, n-hexyl, isohexyl, cyclohexyl, n-heptyl, octyl, cyclopropyl, cyclobutyl, norbornyl Base etc.

术语“烯基”是指可为直链或具支链且具有至少一个且通常1个、2个或3个碳碳双键的单价不饱和烃基团。除非另有定义，否则所述烯基通常含有2个到20个碳原子且包括(例如)-C _2-4烯基、-C _2-6烯基及-C _2-10烯基。代表性烯基包括(例如)乙烯基、正丙烯基、异丙烯基、正-丁-2-烯基、丁-3-烯基、正-己-3-烯基等。 The term "alkenyl" refers to a monovalent unsaturated hydrocarbon group which may be straight-chain or branched and which has at least one and usually 1, 2 or 3 carbon-carbon double bonds. Unless otherwise defined, such alkenyl groups typically contain 2 to 20 carbon atoms and include, for example, -C _2-4 alkenyl, -C _2-6 alkenyl, and -C _2-10 alkenyl. Representative alkenyl groups include, for example, ethenyl, n-propenyl, isopropenyl, n-but-2-enyl, but-3-enyl, n-hex-3-enyl, and the like.

术语“芳环”意指具有单环(例如，苯基)或稠合环的单价芳香族烃。稠合环***包括那些完全不饱和的环***(例如，萘)以及那些部分不饱和的环***(例如，1,2,3,4-四氢萘)。除非另有定义，否则所述芳环通常含有6个到26个碳环原子且包括(例如)-C _6-10芳基。代表性芳基包括(例如)苯基、甲基苯基、丙基苯基、异丙基苯基、苯甲基和萘-1-基、萘-2-基等等。 The term "aromatic ring" means a monovalent aromatic hydrocarbon having a single ring (eg, phenyl) or fused rings. Fused ring systems include those that are fully unsaturated (eg, naphthalene) as well as those that are partially unsaturated (eg, 1,2,3,4-tetrahydronaphthalene). Unless otherwise defined, the aryl ring typically contains 6 to 26 carbon ring atoms and includes, for example, -C _6-10 aryl. Representative aryl groups include, for example, phenyl, methylphenyl, propylphenyl, isopropylphenyl, benzyl, and naphthalen-1-yl, naphthalen-2-yl, and the like.

术语“环烷基”涵盖环状烷基。环烷基可为3-20个碳原子的环烷基、6-20个碳原子的环烷基、3-12个碳原子的环烷基、3-6个碳原子的环烷基。例如，环烷基可为环丙基、环丁基、环戊基、环己基等。另外，环烷基可以是任选地被取代的。The term "cycloalkyl" encompasses cyclic alkyl groups. The cycloalkyl group may be a cycloalkyl group of 3-20 carbon atoms, a cycloalkyl group of 6-20 carbon atoms, a cycloalkyl group of 3-12 carbon atoms, or a cycloalkyl group of 3-6 carbon atoms. For example, cycloalkyl may be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. Additionally, cycloalkyl groups may be optionally substituted.

术语“卤素”指的是化学元素周期表中第ⅦA族元素，包括氟(F)、氯(Cl)、溴(Br)、碘(I)和砹(At)。The term "halogen" refers to the elements of group VIIA of the periodic table of chemical elements, including fluorine (F), chlorine (Cl), bromine (Br), iodine (I) and astatine (At).

在保持正极和负极材料不变的前提下，改善电化学装置(例如，锂离子电池)的安全性的途径主要包括：在电解液内添加阻燃添加剂；和采用热闭孔隔膜或功能涂敷隔膜。然而，在实际应用过程中，将阻燃添加剂直接加入到电解液中会对锂离子电池的电化学性能造成严重的不利影响。采用热闭孔隔膜或功能涂敷隔膜虽然能够提升锂离子电池的安全性，对于电池正常工作时的电化学性能影响较小，但依然无法从根本上控制电池热失控速率。Under the premise of keeping the positive and negative electrode materials unchanged, the ways to improve the safety of electrochemical devices (such as lithium-ion batteries) mainly include: adding flame retardant additives in the electrolyte; and using thermal closed-cell separators or functional coatings diaphragm. However, in practical applications, directly adding flame retardant additives to the electrolyte will have a serious adverse effect on the electrochemical performance of lithium-ion batteries. Although the use of thermally closed-cell separators or functional coating separators can improve the safety of lithium-ion batteries and have little impact on the electrochemical performance of batteries during normal operation, they still cannot fundamentally control the thermal runaway rate of batteries.

本申请通过使用包括聚(酰胺酸)的正极活性物质和包括二氟亚磷酸酯化合物的电解液的组合解决了上述问题。聚(酰胺酸)可以在160℃以上的温度下可转化为聚酰亚胺。在热失控发生温升较快的情况下，正极活性物质层中的聚(酰胺酸)可以快速吸收热量，发生聚合反应，生成具有绝缘功能的聚酰亚胺，从而阻隔正极活性物质的离子和电子传输，快速且有效地提升锂离子电池的安全性。然而，在常温下，聚(酰胺酸)会影响锂离子电池的浮充性能。在电解液中添加二氟亚磷酸酯化合物有助于改善锂离子电池的浮充性能，这是因为聚(酰胺酸)和二氟亚磷酸酯化合物之间存在大量的分子间作用力，从而减轻了常温下聚(酰胺酸)对锂离子的传输中离子电导的影响。此外，在高温高压下，聚(酰胺酸)和二氟亚磷酸酯化合物可形成复合聚合物，其对于改善锂离子电池的浮充性能和安全性的改善更为有效。因此，本申请的正极活性物质和电解液的特定组合可显著改善电化学装置的浮充性能和安全性。The present application solves the above-mentioned problems by using a combination of a positive electrode active material including poly(amic acid) and an electrolyte solution including a difluorophosphite compound. Poly(amic acid) can be converted into polyimide at temperatures above 160°C. In the case of rapid temperature rise due to thermal runaway, the poly(amic acid) in the positive electrode active material layer can quickly absorb heat, undergo a polymerization reaction, and generate polyimide with insulating function, thereby blocking the ions and particles of the positive electrode active material. Electron transport, fast and efficient enhancement of lithium-ion battery safety. However, at room temperature, poly(amic acid) can affect the float charge performance of Li-ion batteries. The addition of difluorophosphite compounds in the electrolyte helps to improve the float performance of lithium-ion batteries, because there are a large number of intermolecular forces between poly(amic acid) and difluorophosphite compounds, thereby relieving the The effect of poly(amic acid) on the ion conductance in the transport of lithium ions at room temperature was studied. In addition, under high temperature and pressure, poly(amic acid) and difluorophosphite compounds can form composite polymers, which are more effective for improving the float performance and safety of lithium-ion batteries. Therefore, the specific combination of the positive electrode active material and the electrolyte solution of the present application can significantly improve the float charge performance and safety of the electrochemical device.

I、正极I. Positive electrode

正极包括正极集流体和形成在所述正极集流体上的正极活性物质层。正极活性物质层可以是一层或多层。正极活性物质层包括正极活性物质，多层正极活性物质中的每层可以包含相同或不同的正极活性物质。The positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector. The positive active material layer may be one or more layers. The positive active material layer includes positive active materials, and each layer of the multilayer positive active materials may contain the same or different positive active materials.

本申请的电化学装置的一个主要特征在于所述正极活性物质层包括聚(酰胺酸)。A main feature of the electrochemical device of the present application is that the positive electrode active material layer includes poly(amic acid).

在一些实施例中，所述聚(酰胺酸)包括式I化合物：In some embodiments, the poly(amic acid) comprises a compound of formula I:

其中：in:

n为5至20的整数。n is an integer of 5-20.

在一些实施例中，所述聚(酰胺酸)包括式I-1化合物(BPDA/PDA PAA)：In some embodiments, the poly(amic acid) comprises a compound of formula I-1 (BPDA/PDA PAA):

其中n为5至20的整数。Wherein n is an integer from 5 to 20.

在一些实施例中，基于所述正极活性物质层的重量，所述聚(酰胺酸)的含量为a％，a的取值范围为0.5至5。在一些实施例中，a的取值范围为1至3。在一些实施例中，x为0.5、1、2、2.5、3、3.5、4、4.5、5或在由上述任意两个数值所组成的范围内。当正极活性物质层中聚(酰胺酸)的含量在上述范围内时，有助于进一步提升电化学装置的浮充性能和安全性。In some embodiments, based on the weight of the positive electrode active material layer, the content of the poly(amic acid) is a%, and the value of a ranges from 0.5 to 5. In some embodiments, a ranges from 1 to 3. In some embodiments, x is 0.5, 1, 2, 2.5, 3, 3.5, 4, 4.5, 5 or within a range consisting of any two of the above values. When the content of the poly(amic acid) in the positive electrode active material layer is within the above range, it is helpful to further improve the float charge performance and safety of the electrochemical device.

正极活性物质的种类没有特别限制，只要是能够以电化学方式吸藏和释放金属离子(例如，锂离子)即可。在一些实施例中，正极活性物质为含有锂和至少一种过渡金属的物质。正极活性物质的实例可包括，但不限于，锂过渡金属复合氧化物和含锂过渡金属磷酸化合物。The type of positive electrode active material is not particularly limited, as long as it can store and release metal ions (for example, lithium ions) electrochemically. In some embodiments, the positive active material is a material containing lithium and at least one transition metal. Examples of positive active materials may include, but are not limited to, lithium transition metal composite oxides and lithium transition metal phosphate compounds.

在一些实施例中，锂过渡金属复合氧化物中的过渡金属包括V、Ti、Cr、Mn、Fe、Co、Ni、Cu等。在一些实施例中，锂过渡金属复合氧化物包括LiCoO ₂等锂钴复合氧化物、LiNiO ₂等锂镍复合氧化物、LiMnO ₂、LiMn ₂O ₄、Li ₂MnO ₄等锂锰复合氧化物、LiNi _1/3Mn _1/3Co _1/3O ₂、LiNi _0.5Mn _0.3Co _0.2O ₂等锂镍锰钴复合氧化物，其中作为这些锂过渡金属复合氧化物的主体的过渡金属原子的一部分被Na、K、B、F、Al、Ti、V、Cr、Mn、Fe、Co、Li、Ni、Cu、Zn、Mg、Ga、Zr、Si、Nb、Mo、Sn、W等其它元素所取代。锂过渡金属复合氧化物的实例可包括，但不限于，LiNi _0.5Mn _0.5O ₂、LiNi _0.85Co _0.10Al _0.05O ₂、LiNi _0.33Co _0.33Mn _0.33O ₂、LiNi _0.45Co _0.10Al _0.45O ₂、LiMn _1.8Al _0.2O ₄和LiMn _1.5Ni _0.5O ₄等。锂过渡金属复合氧化物的组合的实例包括，但不限于，LiCoO ₂与LiMn ₂O ₄的组合，其中LiMn ₂O ₄中的一部分Mn可被过渡金属所取代(例如，LiNi _0.33Co _0.33Mn _0.33O ₂)，LiCoO ₂中的一部分Co可被过渡金属所取代。 In some embodiments, the transition metals in the lithium transition metal composite oxide include V, Ti, Cr, Mn, Fe, Co, Ni, Cu, and the like. In some embodiments, lithium transition metal composite oxides include lithium cobalt composite oxides such as LiCoO ₂ , lithium nickel composite oxides such as LiNiO ₂ , lithium manganese composite oxides such as LiMnO ₂ , LiMn ₂ O ₄ , Li ₂ MnO ₄ , lithium nickel manganese cobalt composite oxides such as LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , LiNi _0.5 Mn _0.3 Co _0.2 O _{2 ,} etc., in which a part of the transition metal atom which is the main body of these lithium transition metal composite oxides is Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, W and other elements substituted . Examples of lithium transition metal composite oxides may include, but are not limited to, LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.45 Co _0.10 Al _0.45 O ₂ , LiMn _1.8 Al _0.2 O ₄ and LiMn _1.5 Ni _0.5 O ₄ etc. Examples of combinations of lithium transition metal composite oxides include, but are not limited to, combinations of LiCoO ₂ and LiMn ₂ O ₄ , wherein a part of Mn in LiMn ₂ O ₄ may be replaced by transition metals (for example, LiNi _0.33 Co _0.33 Mn _0.33 O ₂ ), part of Co in LiCoO ₂ can be replaced by transition metals.

在一些实施例中，含锂过渡金属磷酸化合物中的过渡金属包括V、Ti、Cr、 Mn、Fe、Co、Ni、Cu等。在一些实施例中，含锂过渡金属磷酸化合物包括LiFePO ₄、Li ₃Fe ₂(PO ₄) ₃、LiFeP ₂O ₇等磷酸铁类、LiCoPO ₄等磷酸钴类，其中作为这些锂过渡金属磷酸化合物的主体的过渡金属原子的一部分被Al、Ti、V、Cr、Mn、Fe、Co、Li、Ni、Cu、Zn、Mg、Ga、Zr、Nb、Si等其它元素所取代。 In some embodiments, the transition metals in the lithium-containing transition metal phosphate compound include V, Ti, Cr, Mn, Fe, Co, Ni, Cu, and the like. In some embodiments, lithium-containing transition metal phosphate compounds include iron phosphates such as LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ) ₃ , LiFeP ₂ O ₇ , and cobalt phosphates such as LiCoPO ₄ , wherein as these lithium transition metal phosphate compounds Some of the transition metal atoms of the main body are replaced by other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, etc.

在一些实施例中，在上述正极活性物质的表面可附着有与其组成不同的物质。表面附着物质的实例可包括，但不限于：氧化铝、二氧化硅、二氧化钛、氧化锆、氧化镁、氧化钙、氧化硼、氧化锑、氧化铋等氧化物；硫酸锂、硫酸钠、硫酸钾、硫酸镁、硫酸钙、硫酸铝等硫酸盐；碳酸锂、碳酸钙、碳酸镁等碳酸盐；碳等。通过在正极活性物质表面附着物质，可以抑制正极活性物质表面的电解液的氧化反应，可以提高电化学装置的寿命。当表面附着物质的量过少时，其效果无法充分表现；当表面附着物质的量过多时，会阻碍锂离子的出入，因而电阻有时会增加。本申请中，将在正极活性物质的表面附着有与其组成不同的物质的正极活性物质也称为“正极活性物质”。In some embodiments, a substance different from its composition may be attached to the surface of the positive electrode active material. Examples of surface attachment substances may include, but are not limited to: oxides such as alumina, silica, titania, zirconia, magnesia, calcium oxide, boron oxide, antimony oxide, bismuth oxide; lithium sulfate, sodium sulfate, potassium sulfate , magnesium sulfate, calcium sulfate, aluminum sulfate and other sulfates; lithium carbonate, calcium carbonate, magnesium carbonate and other carbonates; carbon, etc. By attaching the substance on the surface of the positive electrode active material, the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material can be suppressed, and the life of the electrochemical device can be improved. When the amount of the surface-attached substance is too small, the effect cannot be fully expressed; when the amount of the surface-attached substance is too large, it will hinder the entry and exit of lithium ions, so the resistance may increase. In the present application, a positive electrode active material having a composition different from the positive electrode active material attached to the surface of the positive electrode active material is also referred to as a "positive electrode active material".

在一些实施例中，正极活性物质颗粒的形状包括，但不限于，块状、多面体状、球状、椭圆球状、板状、针状和柱状等。在一些实施例中，正极活性物质颗粒包括一次颗粒、二次颗粒或其组合。在一些实施例中，一次颗粒可以凝集而形成二次颗粒。In some embodiments, the shape of the positive electrode active material particles includes, but is not limited to, block shape, polyhedron shape, spherical shape, ellipsoidal shape, plate shape, needle shape and columnar shape. In some embodiments, the positive active material particles include primary particles, secondary particles, or a combination thereof. In some embodiments, primary particles may agglomerate to form secondary particles.

正极导电材料的种类没有限制，可以使用任何已知的导电材料。正极导电材料的实例可包括，但不限于，天然石墨、人造石墨等石墨；乙炔黑等炭黑；针状焦等无定形碳等碳材料；碳纳米管；石墨烯等。上述正极导电材料可单独使用或任意组合使用。The kind of positive electrode conductive material is not limited, and any known conductive material can be used. Examples of positive electrode conductive materials may include, but are not limited to, graphite such as natural graphite and artificial graphite; carbon black such as acetylene black; carbon materials such as amorphous carbon such as needle coke; carbon nanotubes; graphene and the like. The above positive electrode conductive materials can be used alone or in any combination.

正极活性物质层的制造中使用的正极粘合剂的种类没有特别限制，在涂布法的情况下，只要是在电极制造时使用的液体介质中可溶解或分散的材料即可。正极粘合剂的实例可包括，但不限于，以下中的一种或多种：聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯、聚甲基丙烯酸甲酯、聚酰亚胺、芳香族聚酰胺、纤维素、硝酸纤维素等树脂系高分子；丁苯橡胶(SBR)、丁腈橡胶(NBR)、氟橡胶、异戊二烯橡胶、聚丁橡胶、乙烯-丙烯橡胶等橡胶状高分子；苯乙烯·丁二烯·苯乙烯嵌段共聚物或其氢化物、乙烯·丙烯·二烯三元共聚物(EPDM)、苯乙烯·乙烯·丁二烯·乙烯共聚物、苯乙烯·异戊二烯·苯乙烯嵌段共聚物或其氢化物等热塑性弹性体状高分子；间规-1,2-聚丁二烯、聚乙酸乙烯酯、乙烯·乙酸乙烯酯共聚物、丙烯·α-烯烃共聚物等软质树脂状高分子；聚偏二氟乙烯(PVDF)、聚四氟乙烯、氟化聚偏二氟乙烯、聚四氟乙烯·乙烯共聚物等氟系高分子；具有碱金属离子(特别是锂离子)的离子传导性的高分子组合物等。上述正极粘合剂可单独使用或任意组合使用。The type of positive electrode binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of the coating method, any material can be dissolved or dispersed in the liquid medium used in electrode production. Examples of positive electrode binders may include, but are not limited to, one or more of the following: polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, Aramid, cellulose, nitrocellulose and other resin-based polymers; styrene-butadiene rubber (SBR), nitrile rubber (NBR), fluororubber, isoprene rubber, polybutadiene rubber, ethylene-propylene rubber and other rubber Shaped polymer; styrene-butadiene-styrene block copolymer or its hydrogenated product, ethylene-propylene-diene terpolymer (EPDM), styrene-ethylene-butadiene-ethylene copolymer, benzene Thermoplastic elastomeric polymers such as ethylene-isoprene-styrene block copolymer or its hydrogenated products; syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymer, Soft resinous polymers such as propylene-α-olefin copolymers; Fluorine-based polymers such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene-ethylene copolymers ; Ion-conductive polymer compositions with alkali metal ions (especially lithium ions), etc. The above positive electrode binders may be used alone or in any combination.

用于形成正极浆料的溶剂的种类没有限制，只要是能够溶解或分散正极活性物质、导电材料、正极粘合剂和根据需要使用的增稠剂的溶剂即可。用于形成正极浆料的溶剂的实例可包括水系溶剂和有机系溶剂中的任一种。水系介质的实例可包括，但不限于，水和醇与水的混合介质等。有机系介质的实例可包括，但不限于，己烷等脂肪族烃类；苯、甲苯、二甲苯、甲基萘等芳香族烃类；喹啉、吡啶等杂环化合物；丙酮、甲基乙基酮、环己酮等酮类；乙酸甲酯、丙烯酸甲酯等酯类；二亚乙基三胺、N,N-二甲氨基丙胺等胺类；二***、环氧丙烷、四氢呋喃(THF)等醚类；N-甲基吡咯烷酮(NMP)、二甲基甲酰胺、二甲基乙酰胺等酰胺类；六甲基磷酰胺、二甲基亚砜等非质子性极性溶剂等。The kind of solvent used to form the positive electrode slurry is not limited as long as it is a solvent capable of dissolving or dispersing the positive electrode active material, conductive material, positive electrode binder, and thickener used as needed. Examples of the solvent used to form the positive electrode slurry may include any one of aqueous solvents and organic solvents. Examples of the aqueous medium may include, but are not limited to, water, a mixed medium of alcohol and water, and the like. Examples of organic media may include, but are not limited to, aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; acetone, methyl ethyl ketones such as ketone and cyclohexanone; esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N,N-dimethylaminopropylamine; diethyl ether, propylene oxide, tetrahydrofuran (THF ) and other ethers; amides such as N-methylpyrrolidone (NMP), dimethylformamide, and dimethylacetamide; aprotic polar solvents such as hexamethylphosphoramide and dimethyl sulfoxide, etc.

增稠剂通常是为了调节浆料的粘度而使用的。在使用水系介质的情况下，可使用增稠剂和丁苯橡胶(SBR)乳液进行浆料化。增稠剂的种类没有特别限制，其实例可包括，但不限于，羧甲基纤维素、甲基纤维素、羟甲基纤维素、乙基纤维素、聚乙烯醇、氧化淀粉、磷酸化淀粉、酪蛋白和它们的盐等。上述增稠剂可单独使用或任意组合使用。Thickeners are generally used to adjust the viscosity of the slurry. In the case of using an aqueous medium, thickeners and styrene-butadiene rubber (SBR) emulsions can be used for slurrying. The kind of thickener is not particularly limited, and examples thereof may include, but are not limited to, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch , casein and their salts, etc. The above-mentioned thickeners can be used alone or in any combination.

正极集流体的种类没有特别限制，其可为任何已知适于用作正极集流体的材质。正极集流体的实例可包括，但不限于，铝、不锈钢、镍镀层、钛、钽等金属材料；碳布、碳纸等碳材料。在一些实施例中，正极集流体为金属材料。在一些实施例中，正极集流体为铝。The type of the positive electrode collector is not particularly limited, and it can be any known material suitable for use as the positive electrode collector. Examples of the positive current collector may include, but are not limited to, metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; carbon materials such as carbon cloth and carbon paper. In some embodiments, the positive current collector is a metal material. In some embodiments, the positive current collector is aluminum.

为了降低正极集流体和正极活性物质层的电子接触电阻，正极集流体的表面可包括导电助剂。导电助剂的实例可包括，但不限于，碳和金、铂、银等贵金属类。In order to reduce the electronic contact resistance of the positive electrode current collector and the positive electrode active material layer, the surface of the positive electrode current collector may include a conductive aid. Examples of conductive aids may include, but are not limited to, carbon and noble metals such as gold, platinum, and silver.

正极可以通过在集流体上形成含有正极活性物质和粘结剂的正极活性物质层来制作。使用正极活性物质的正极的制造可以通过常规方法来进行，即，将正极活性物质和粘结剂、以及根据需要的导电材料和增稠剂等进行干式混合，制成片状，将所得到的片状物压接至正极集流体上；或者将这些材料溶解或分散于液体介质中而制成浆料，将该浆料涂布到正极集流体上并进行干燥，从而在集流体上形成正极活性物质层，由此可以得到正极。The positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. The manufacture of the positive electrode using the positive electrode active material can be carried out by a conventional method, that is, the positive electrode active material and the binder, as well as the conductive material and thickener as required, etc. are dry mixed, made into a sheet, and the obtained The sheet is pressed onto the positive current collector; or these materials are dissolved or dispersed in a liquid medium to make a slurry, and the slurry is coated on the positive current collector and dried to form a positive electrode current collector. A positive electrode active material layer, whereby a positive electrode can be obtained.

II、电解液II. Electrolyte

本申请的电化学装置中的使用的电解液包括电解质和溶解该电解质的溶剂。The electrolytic solution used in the electrochemical device of the present application includes an electrolyte and a solvent for dissolving the electrolyte.

本申请的电化学装置另一主要特征在于所述电解液包括二氟亚磷酸酯化合物。Another main feature of the electrochemical device of the present application is that the electrolyte solution includes a difluorophosphite compound.

在一些实施例中，所述二氟亚磷酸酯化合物包括式II化合物：In some embodiments, the difluorophosphite compound includes a compound of formula II:

A-OPF ₂(式II)， A-OPF ₂ (Formula II),

在一些实施例中，所述二氟亚磷酸酯化合物包括醚键。含有醚键的二氟亚磷酸酯化合物可更好地与聚(酰胺酸)相结合，使得在热失控发生时能够迅速响应而发生聚合反应，进一步提升电化学装置的浮充性能和安全性。In some embodiments, the difluorophosphite compound includes ether linkages. The difluorophosphite compound containing ether bonds can be better combined with poly(amic acid), so that when thermal runaway occurs, it can respond quickly and undergo polymerization reaction, further improving the float charge performance and safety of the electrochemical device.

在一些实施例中，所述二氟亚磷酸酯化合物包括以下化合物中的至少一种：In some embodiments, the difluorophosphite 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，所述二氟亚磷酸酯化合物的含量为b％，b的取值范围为0.1至5。在一些实施例中，b的取值范围为0.5至5。在一些实施例中，x为0.1、0.5、1、1.5、2、2.5、3、3.5、4、4.5、5或在由上述任意两个数值所组成的范围内。当电解液中二氟亚磷酸酯化合物的含量在上述范围内时，有助于进一步提升电化学装置的浮充性能和安全性。In some embodiments, based on the weight of the electrolytic solution, the content of the difluorophosphite compound is b%, and the value of b ranges from 0.1 to 5. In some embodiments, b ranges from 0.5 to 5. In some embodiments, x is 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or within a range consisting of any two values above. When the content of the difluorophosphite compound in the electrolyte is within the above range, it is helpful to further improve the float charge performance and safety of the electrochemical device.

在一些实施例中，a和b满足：0.1≤a/b≤5。在一些实施例中，a和b满足：0.2≤a/b≤2.5。在一些实施例中，a和b满足：0.5≤a/b≤2。在一些实施例中，a和b满足：1≤a/b≤1.5。在一些实施例中，a/b为0.1、0.2、0.5、1、2、2.5、3、3.5、4、4.5、5或在由上述任意两个数值所组成的范围内。当正极活性物质层中聚(酰胺酸)的含量和电解液中二氟亚磷酸酯化合物的含量满足上述关系时，有助于进一步提升电化学装置的浮充性能和安全性。In some embodiments, a and b satisfy: 0.1≦a/b≦5. In some embodiments, a and b satisfy: 0.2≦a/b≦2.5. In some embodiments, a and b satisfy: 0.5≦a/b≦2. In some embodiments, a and b satisfy: 1≤a/b≤1.5. In some embodiments, a/b is 0.1, 0.2, 0.5, 1, 2, 2.5, 3, 3.5, 4, 4.5, 5 or within a range consisting of any two values above. When the content of the poly(amic acid) in the positive electrode active material layer and the content of the difluorophosphite compound in the electrolyte satisfy the above relationship, it is helpful to further improve the float charge performance and safety of the electrochemical device.

在一些实施例中，所述电解液还包括含硫氧双键的化合物，所述含硫氧双键的化合物包括以下化合物中的至少一者：环状硫酸酯、链状硫酸酯、链状磺酸酯、环状磺酸酯、链状亚硫酸酯或环状亚硫酸酯或式III化合物：In some embodiments, the electrolyte solution further includes a compound containing a sulfur-oxygen double bond, and the compound containing a sulfur-oxygen double bond includes at least one of the following compounds: cyclic sulfate, chain sulfate, chain Sulfonate, cyclic sulfonate, chain sulfite or cyclic sulfite or compound of formula III:

其中：in:

W选自

W selected from

L选自单键或亚甲基；L is selected from a single bond or methylene;

m为1至4的整数；m is an integer from 1 to 4;

n为0至2的整数；且n is an integer from 0 to 2; and

p为0至6的整数。p is an integer of 0 to 6.

在一些实施例中，所述式III化合物选自以下中的至少一种：In some embodiments, the compound of formula III is selected from at least one of the following:

当在电解液中同时包含二氟亚磷酸酯化合物和含硫氧双键化合物时，可以进一步改善热失控条件下正极活性物质的结构稳定性，同时可以加快高温下聚(酰胺酸)和二氟亚磷酸酯化合物之间热聚合反应，从而实现快速降低离子电导和电子电导，进一步改善电化学装置的浮充性能和安全性。When a difluorophosphite compound and a sulfur-oxygen double bond compound are included in the electrolyte, the structural stability of the positive electrode active material under thermal runaway conditions can be further improved, and at the same time, it can accelerate the formation of poly(amic acid) and difluoride at high temperature. The thermal polymerization reaction between the phosphite compounds can rapidly reduce the ion conductance and electron conductance, and further improve the float charge performance and safety of the electrochemical device.

在一些实施例中，基于所述电解液的重量，所述二氟亚磷酸酯化合物的含量为b％，所述含硫氧双键的化合物的含量为c％，b和c满足：1≤b+c≤8和0.4≤b/c≤5。在一些实施例中，2≤b+c≤6。在一些实施例中，3≤b+c≤5。在一些实施例中，b+c为1、2、3、4、5、6、7、8或在由上述任意两个数值所组成的范围内。在一些实施例中，0.5≤b/c≤3。在一些实施例中，1≤b/c≤2。在一些实施例中，b/c为0.4、0.5、1、2、3、4、5或在由上述任意两个数值所组成的范围内。当电解液中二氟亚磷酸酯化合物的含量与含硫氧双键的化合物的含量满足上述关系时，有助于进一步提升电化学装置的浮充性能和安全性。In some embodiments, based on the weight of the electrolyte, the content of the difluorophosphite compound is b%, the content of the compound containing sulfur and oxygen double bonds is c%, and b and c satisfy: 1≤ b+c≤8 and 0.4≤b/c≤5. In some embodiments, 2≤b+c≤6. In some embodiments, 3≤b+c≤5. In some embodiments, b+c is 1, 2, 3, 4, 5, 6, 7, 8 or within a range consisting of any two values above. In some embodiments, 0.5≤b/c≤3. In some embodiments, 1≦b/c≦2. In some embodiments, b/c is 0.4, 0.5, 1, 2, 3, 4, 5 or within a range consisting of any two values above. When the content of the difluorophosphite compound and the content of the sulfur-oxygen double bond-containing compound in the electrolyte satisfies the above relationship, it is helpful to further improve the float charge performance and safety of the electrochemical device.

在一些实施例中，基于所述电解液的重量，所述含硫氧双键的化合物的含量为c％，c的取值范围为0.1至8。在一些实施例中，c的取值范围为0.1至5。在一些实施例中，其中c的取值范围为0.1至3。在一些实施例中，c的取值范围为0.1至1.5。在一些实施例中，c为0.1、0.3、0.5、1、2、2.5、3、3.5、4、4.5、5、8或在由上述任意两个数值所组成的范围内。当电解液中含硫氧双键的化合物的含量满足上述关系时，有助于进一步提升电化学装置的浮充性能和安全性。In some embodiments, based on the weight of the electrolyte, the content of the sulfur-oxygen double bond-containing compound is c%, and the value of c ranges from 0.1 to 8. In some embodiments, c ranges from 0.1 to 5. In some embodiments, the value of c ranges from 0.1 to 3. In some embodiments, c ranges from 0.1 to 1.5. In some embodiments, c is 0.1, 0.3, 0.5, 1, 2, 2.5, 3, 3.5, 4, 4.5, 5, 8 or within a range consisting of any two of the above values. When the content of the sulfur-oxygen double bond-containing compound in the electrolyte satisfies the above relationship, it will help to further improve the float performance and safety of the electrochemical device.

在一些实施例中，所述电解液进一步包含现有技术中已知的任何可作为电解液的溶剂的非水溶剂。In some embodiments, the electrolyte solution further comprises any non-aqueous solvent known in the prior art as a solvent for the electrolyte solution.

在一些实施例中，所述非水溶剂包括，但不限于，以下中的一种或多种：环状碳酸酯、链状碳酸酯、环状羧酸酯、链状羧酸酯、环状醚、链状醚、含磷有机溶剂、含硫有机溶剂和芳香族含氟溶剂。In some embodiments, the non-aqueous solvent includes, but is not limited to, one or more of the following: cyclic carbonate, chain carbonate, cyclic carboxylate, chain carboxylate, cyclic Ethers, chain ethers, phosphorus-containing organic solvents, sulfur-containing organic solvents, and aromatic fluorinated solvents.

在一些实施例中，所述环状碳酸酯的实例可包括，但不限于，以下中的一种或多种：碳酸亚乙酯(EC)、碳酸亚丙酯(PC)和碳酸亚丁酯。在一些实施例中，所述环状碳酸酯具有3-6个碳原子。In some embodiments, examples of the cyclic carbonate may include, but are not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate. In some embodiments, the cyclic carbonate has 3-6 carbon atoms.

在一些实施例中，所述链状碳酸酯的实例可包括，但不限于，以下中的一种或多种：碳酸二甲酯、碳酸甲乙酯、碳酸二乙酯(DEC)、碳酸甲基正丙基酯、碳酸乙基正丙基酯、碳酸二正丙酯等链状碳酸酯等。被氟取代的链状碳酸酯的实例可包括，但不限于，以下中的一种或多种：双(氟甲基)碳酸酯、双(二氟甲基)碳酸酯、双(三氟甲基)碳酸酯、双(2-氟乙基)碳酸酯、双(2,2-二氟乙基)碳酸酯、双(2,2,2-三氟乙基)碳酸酯、2-氟乙基甲基碳酸酯、2,2-二氟乙基甲基碳酸酯和2,2,2-三氟乙基甲基碳酸酯等。In some embodiments, examples of the chain carbonate may include, but are not limited to, one or more of the following: dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate (DEC), methyl carbonate Chain carbonates such as ethyl n-propyl carbonate, ethyl n-propyl carbonate, di-n-propyl carbonate, etc. Examples of chain carbonates substituted with fluorine may include, but are not limited to, one or more of the following: bis(fluoromethyl)carbonate, bis(difluoromethyl)carbonate, bis(trifluoromethyl)carbonate base) carbonate, bis(2-fluoroethyl)carbonate, bis(2,2-difluoroethyl)carbonate, bis(2,2,2-trifluoroethyl)carbonate, 2-fluoroethyl methyl carbonate, 2,2-difluoroethyl methyl carbonate and 2,2,2-trifluoroethyl methyl carbonate, etc.

在一些实施例中，所述环状羧酸酯的实例可包括，但不限于，以下中的一种或多种：γ-丁内酯和γ-戊内酯中的一种或多种。在一些实施例中，环状羧酸酯的部分氢原子可被氟取代。In some embodiments, examples of the cyclic carboxylate may include, but are not limited to, one or more of the following: one or more of γ-butyrolactone and γ-valerolactone. In some embodiments, some of the hydrogen atoms of the cyclic carboxylate may be replaced by fluorine.

在一些实施例中，所述链状羧酸酯的实例可包括，但不限于，以下中的一种或多种：乙酸甲酯、乙酸乙酯、乙酸丙酯、乙酸异丙酯、乙酸丁酯、乙酸仲丁酯、乙酸异丁酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丙酸异丙酯、丁酸甲酯、丁酸乙酯、丁酸丙酯、异丁酸甲酯、异丁酸乙酯、戊酸甲酯、戊酸乙酯、特戊酸甲酯和特戊酸乙酯等。在一些实施例中，链状羧酸酯的部分氢原子可被氟取代。在一些实施例中，氟取代的链状羧酸酯的实例可包括，但不限于，三氟乙酸甲酯、三氟乙酸乙酯、三氟乙酸丙酯、三氟乙酸丁酯和三氟乙酸2,2,2-三氟乙酯等。In some embodiments, examples of the chain carboxylate may include, but are not limited to, one or more of the following: methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate ester, sec-butyl acetate, isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, butyric acid Propyl ester, methyl isobutyrate, ethyl isobutyrate, methyl valerate, ethyl valerate, methyl pivalate and ethyl pivalate, etc. In some embodiments, part of the hydrogen atoms of the chain carboxylate may be substituted by fluorine. In some embodiments, examples of fluorine-substituted chain carboxylic acid esters may include, but are not limited to, methyl trifluoroacetate, ethyl trifluoroacetate, propyl trifluoroacetate, butyl trifluoroacetate, and trifluoroacetic acid 2,2,2-trifluoroethyl ester, etc.

在一些实施例中，所述环状醚的实例可包括，但不限于，以下中的一种或多种：四氢呋喃、2-甲基四氢呋喃、1,3-二氧戊环、2-甲基1,3-二氧戊环、4-甲基1,3-二氧戊环、1,3-二氧六环、1,4-二氧六环和二甲氧基丙烷。In some embodiments, examples of the cyclic ether may include, but are not limited to, one or more of the following: tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 2-methyl 1,3-dioxolane, 4-methyl 1,3-dioxolane, 1,3-dioxane, 1,4-dioxane and dimethoxypropane.

在一些实施例中，所述链状醚的实例可包括，但不限于，以下中的一种或多种：二甲氧基甲烷、1,1-二甲氧基乙烷、1,2-二甲氧基乙烷、二乙氧基甲烷、1,1-二乙氧基乙烷、1,2-二乙氧基乙烷、乙氧基甲氧基甲烷、1,1-乙氧基甲氧基乙烷和1,2-乙氧基甲氧基乙烷等。In some embodiments, examples of the chain ethers may include, but are not limited to, one or more of the following: dimethoxymethane, 1,1-dimethoxyethane, 1,2- Dimethoxyethane, diethoxymethane, 1,1-diethoxyethane, 1,2-diethoxyethane, ethoxymethoxymethane, 1,1-ethoxy Methoxyethane and 1,2-ethoxymethoxyethane, etc.

在一些实施例中，所述含磷有机溶剂的实例可包括，但不限于，以下中的一种或多种：磷酸三甲酯、磷酸三乙酯、磷酸二甲基乙酯、磷酸甲基二乙酯、磷酸亚乙基甲酯、磷酸亚乙基乙酯、磷酸三苯酯、亚磷酸三甲酯、亚磷酸三乙酯、亚磷酸三苯酯、磷酸三(2,2,2-三氟乙基)酯和磷酸三(2,2,3,3,3-五氟丙基)酯等。In some embodiments, examples of the phosphorus-containing organic solvent may include, but are not limited to, one or more of the following: trimethyl phosphate, triethyl phosphate, dimethyl ethyl phosphate, methyl phosphate Diethyl ester, ethylene methyl phosphate, ethylene ethyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tris(2,2,2- phosphate Trifluoroethyl) ester and tris(2,2,3,3,3-pentafluoropropyl) phosphate, etc.

在一些实施例中，所述含硫有机溶剂的实例可包括，但不限于，以下中的一种或多种：环丁砜、2-甲基环丁砜、3-甲基环丁砜、二甲基砜、二乙基砜、乙基甲基砜、甲基丙基砜、二甲基亚砜、甲磺酸甲酯、甲磺酸乙酯、乙磺酸甲酯、乙磺酸乙酯、硫酸二甲酯、硫酸二乙酯和硫酸二丁酯。在一些实施例中，含硫有机溶剂的部分氢原子可被氟取代。In some embodiments, examples of the sulfur-containing organic solvent may include, but are not limited to, one or more of the following: sulfolane, 2-methylsulfolane, 3-methylsulfolane, dimethylsulfone, disulfone Ethyl sulfone, ethyl methyl sulfone, methyl propyl sulfone, dimethyl sulfoxide, methyl methanesulfonate, ethyl methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate, dimethyl sulfate , diethyl sulfate and dibutyl sulfate. In some embodiments, some hydrogen atoms of the sulfur-containing organic solvent may be replaced by fluorine.

在一些实施例中，所述芳香族含氟溶剂包括，但不限于，以下中的一种或多种：氟苯、二氟苯、三氟苯、四氟苯、五氟苯、六氟苯和三氟甲基苯。In some embodiments, the aromatic fluorinated solvent includes, but is not limited to, one or more of the following: fluorobenzene, difluorobenzene, trifluorobenzene, tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene and trifluoromethylbenzene.

在一些实施例中，本申请的电解液中使用的溶剂包括环状碳酸酯、链状碳酸酯、环状羧酸酯、链状羧酸酯及其组合。在一些实施例中，本申请的电解液中使用的溶剂包含选自由下列物质组成的群组的有机溶剂：碳酸亚乙酯、碳酸亚丙酯、碳酸二乙酯、丙酸乙酯、丙酸丙酯、乙酸正丙酯、乙酸乙酯及其组合。在一些实施例中，本申请的电解液中使用的溶剂包含：碳酸亚乙酯、碳酸亚丙酯、碳酸二乙酯、丙酸乙酯、丙酸丙酯、γ-丁内酯及其组合。In some embodiments, the solvent used in the electrolyte of the present application includes cyclic carbonates, chain carbonates, cyclic carboxylates, chain carboxylates, and combinations thereof. In some embodiments, the solvent used in the electrolyte of the present application comprises an organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl propionate, propionic acid Propyl ester, n-propyl acetate, ethyl acetate and combinations thereof. In some embodiments, the solvent used in the electrolyte of the present application comprises: ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl propionate, propyl propionate, γ-butyrolactone and combinations thereof .

在一些实施例中，电解质没有特别限制，可以任意地使用作为电解质公知的物质。在锂二次电池的情况下，通常使用锂盐。电解质的实例可包括，但不限于，LiPF ₆、LiBF ₄、LiClO ₄、LiAlF ₄、LiSbF ₆、LiWF ₇等无机锂盐；LiWOF ₅等钨酸锂类；HCO ₂Li、CH ₃CO ₂Li、CH ₂FCO ₂Li、CHF ₂CO ₂Li、CF ₃CO ₂Li、CF ₃CH ₂CO ₂Li、CF ₃CF ₂CO ₂Li、CF ₃CF ₂CF ₂CO ₂Li、CF ₃CF ₂CF ₂CF ₂CO ₂Li等羧酸锂盐类；FSO ₃Li、CH ₃SO ₃Li、CH ₂FSO ₃Li、CHF ₂SO ₃Li、CF ₃SO ₃Li、CF ₃CF ₂SO ₃Li、CF ₃CF ₂CF ₂SO ₃Li、CF ₃CF ₂CF ₂CF ₂SO ₃Li等磺酸锂盐类；LiN(FCO) ₂、LiN(FCO)(FSO ₂)、LiN(FSO ₂) ₂、LiN(FSO ₂)(CF ₃SO ₂)、LiN(CF ₃SO ₂) ₂、LiN(C ₂F ₅SO ₂) ₂、环状1,2-全氟乙烷双磺酰亚胺锂、环状1,3-全氟丙烷双磺酰亚胺锂、LiN(CF ₃SO ₂)(C ₄F ₉SO ₂)等酰亚胺锂盐类； LiC(FSO ₂) ₃、LiC(CF ₃SO ₂) ₃、LiC(C ₂F ₅SO ₂) ₃等甲基化锂盐类；双(丙二酸根合)硼酸锂盐、二氟(丙二酸根合)硼酸锂盐等(丙二酸根合)硼酸锂盐类；三(丙二酸根合)磷酸锂、二氟双(丙二酸根合)磷酸锂、四氟(丙二酸根合)磷酸锂等(丙二酸根合)磷酸锂盐类；以及LiPF ₄(CF ₃) ₂、LiPF ₄(C ₂F ₅) ₂、LiPF ₄(CF ₃SO ₂) ₂、LiPF ₄(C ₂F ₅SO ₂) ₂、LiBF ₃CF ₃、LiBF ₃C ₂F ₅、LiBF ₃C ₃F ₇、LiBF ₂(CF ₃) ₂、LiBF ₂(C ₂F ₅) ₂、LiBF ₂(CF ₃SO ₂) ₂、LiBF ₂(C ₂F ₅SO ₂) ₂等含氟有机锂盐类；二氟草酸硼酸锂、双(草酸)硼酸锂等草酸硼酸锂盐类；四氟草酸根合磷酸锂、二氟双(草酸根合)磷酸锂、三(草酸根合)磷酸锂等草酸根合磷酸锂盐类等。 In some embodiments, the electrolyte is not particularly limited, and any known substance as an electrolyte can be used arbitrarily. In the case of lithium secondary batteries, lithium salts are generally used. Examples of electrolytes may include, but are not limited to, inorganic lithium salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAlF ₄ , LiSbF ₆ , LiWF ₇ ; lithium tungstates 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 Lithium carboxylate salts such as CF ₂ CO ₂ Li; FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃ SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ CF ₂ SO ₃ Li and other sulfonate lithium salts; LiN(FCO) 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 lithium 1,2-perfluoroethanebissulfonylimide, cyclic 1 , 3-perfluoropropane bissulfonylimide lithium, LiN(CF ₃ SO ₂ )(C ₄ F ₉ SO ₂ ) and other imide lithium salts; LiC(FSO ₂ ) ₃ , LiC(CF ₃ SO ₂ ) _3. LiC(C ₂ F ₅ SO ₂ ) ₃ and other methylated lithium salts; bis(malonato)borate lithium salt, difluoro(malonate) borate lithium salt, etc. (malonato)boric acid Lithium salts; lithium tris(malonato)phosphate, lithium difluorobis(malonato)phosphate, lithium tetrafluoro(malonato)phosphate and other (malonato)phosphate lithium salts; 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 Organolithium salts; lithium difluorooxalate borate, lithium bis(oxalate)borate and other lithium oxalate borate salts; lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, tri(oxalato)phosphoric acid Lithium oxalatophosphate lithium salts, etc.

在一些实施例中，电解质选自LiPF ₆、LiSbF ₆、FSO ₃Li、CF ₃SO ₃Li、LiN(FSO ₂) ₂、LiN(FSO ₂)(CF ₃SO ₂)、LiN(CF ₃SO ₂) ₂、LiN(C ₂F ₅SO ₂) ₂、环状1,2-全氟乙烷双磺酰亚胺锂、环状1,3-全氟丙烷双磺酰亚胺锂、LiC(FSO ₂) ₃、LiC(CF ₃SO ₂) ₃、LiC(C ₂F ₅SO ₂) ₃、LiBF ₃CF ₃、LiBF ₃C ₂F ₅、LiPF ₃(CF ₃) ₃、LiPF ₃(C ₂F ₅) ₃、二氟草酸硼酸锂、双(草酸)硼酸锂或二氟双(草酸根合)磷酸锂，其有助于改善电化学装置的输出功率特性、高倍率充放电特性、高温保存特性和循环特性等。 In some embodiments, the electrolyte is selected from LiPF ₆ , LiSbF ₆ , FSO ₃ Li, CF ₃ SO ₃ Li, 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 lithium 1,2-perfluoroethanebissulfonimide, cyclic lithium 1,3-perfluoropropanebissulfonimide, LiC(FSO ₂ ) ₃ , LiC(CF ₃ SO ₂ ) ₃ , LiC(C ₂ F ₅ SO ₂ ) ₃ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) _3. Lithium difluorooxalate borate, lithium bis(oxalate)borate or lithium difluorobis(oxalato)phosphate, which help to improve the output power characteristics, high-rate charge and discharge characteristics, and high-temperature storage characteristics of electrochemical devices and cycle characteristics, etc.

电解质的含量没有特别限制，只要不损害本申请的效果即可。在一些实施例中，电解液中的锂的总摩尔浓度为大于0.3mol/L以上、大于0.4mol/L或大于0.5mol/L。在一些实施例中，电解液中的锂的总摩尔浓度为小于3mol/L、小于2.5mol/L或小于2.0mol/L以下。在一些实施例中，电解液中的锂的总摩尔浓度在上述任意两个数值所组成的范围内。当电解质浓度在上述范围内时，作为带电粒子的锂不会过少，并且可以使粘度处于适当的范围，因而容易确保良好的电导率。The content of the electrolyte is not particularly limited as long as the effect of the present application is not impaired. In some embodiments, the total molar concentration of lithium in the electrolyte is greater than 0.3 mol/L, greater than 0.4 mol/L or greater than 0.5 mol/L. In some embodiments, the total molar concentration of lithium in the electrolyte is less than 3 mol/L, less than 2.5 mol/L or less than 2.0 mol/L. In some embodiments, the total molar concentration of lithium in the electrolyte is within the range formed by any two values above. When the electrolyte concentration is within the above range, the lithium as charged particles will not be too small, and the viscosity can be kept in an appropriate range, so it is easy to ensure good electrical conductivity.

当使用两种以上的电解质的情况下，电解质包括至少一种为选自由单氟磷酸盐、硼酸盐、草酸盐和氟磺酸盐组成的组中的盐。在一些实施例中，电解质包括选自由单氟磷酸盐、草酸盐和氟磺酸盐组成的组中的盐。在一些实施例中，电解质包括锂盐。在一些实施例中，基于电解质的重量，选自由单氟磷酸盐、硼酸盐、草酸盐和氟磺酸盐组成的组中的盐的含量为大于0.01％或大于0.1％。在一些实施例中，基于电解质的重量，选自由单氟磷酸盐、硼酸盐、草酸盐和氟磺酸盐组成的组中的盐的含量为小于20％或小于10％。在一些实施例中，选自由单氟磷酸盐、硼酸盐、草酸盐和氟磺酸盐组成的组中的盐的含量在上述任意两个数值所组成的范围内。When two or more electrolytes are used, the electrolyte includes at least one salt selected from the group consisting of monofluorophosphate, borate, oxalate, and fluorosulfonate. In some embodiments, the electrolyte includes a salt selected from the group consisting of monofluorophosphate, oxalate, and fluorosulfonate. In some embodiments, the electrolyte includes a lithium salt. In some embodiments, the salt selected from the group consisting of monofluorophosphate, borate, oxalate, and fluorosulfonate is present at greater than 0.01% or greater than 0.1% by weight of the electrolyte. In some embodiments, the salt selected from the group consisting of monofluorophosphate, borate, oxalate, and fluorosulfonate comprises less than 20% or less than 10% by weight of the electrolyte. In some embodiments, the content of the salt selected from the group consisting of monofluorophosphate, borate, oxalate and fluorosulfonate is within the range formed by any two of the above values.

在一些实施例中，电解质包含选自由单氟磷酸盐、硼酸盐、草酸盐和氟磺酸盐组成的组中的一种以上物质和除此以外的一种以上的盐。作为除此以外的盐，可以举出在上文中例示的锂盐，在一些实施例中为LiPF ₆、LiN(FSO ₂)(CF ₃SO ₂)、LiN(CF ₃SO ₂) ₂、LiN(C ₂F ₅SO ₂) ₂、环状1,2-全氟乙烷双磺酰亚胺锂、环状1,3-全氟丙烷双磺酰亚胺锂、LiC(FSO ₂) ₃、LiC(CF ₃SO ₂) ₃、LiC(C ₂F ₅SO ₂) ₃、LiBF ₃CF ₃、LiBF ₃C ₂F ₅、LiPF ₃(CF ₃) ₃、LiPF ₃(C ₂F ₅) ₃。在一些实施例中，除此以外的盐为LiPF ₆。 In some embodiments, the electrolyte includes one or more substances selected from the group consisting of monofluorophosphate, borate, oxalate, and fluorosulfonate and one or more salts other than these. Other salts include the lithium salts exemplified above, and in some examples, LiPF ₆ , LiN(FSO ₂ )(CF ₃ SO ₂ ), LiN(CF ₃ SO ₂ ) ₂ , LiN( C ₂ F ₅ SO ₂ ) ₂ , cyclic lithium 1,2-perfluoroethanebissulfonimide, cyclic lithium 1,3-perfluoropropanebissulfonimide, LiC(FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC(C ₂ F ₅ SO ₂ ) ₃ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ . In some embodiments, the additional salt is LiPF ₆ .

在一些实施例中，基于电解质的重量，除此以外的盐的含量为大于0.01％或大于0.1％。在一些实施例中，基于电解质的重量，除此以外的盐的含量为小于20％、小于15％或小于10％。在一些实施例中，除此以外的盐的含量在上述任意两个数值所组成的范围内。具有上述含量的除此以外的盐有助于平衡电解液的电导率和粘度。In some embodiments, the additional salts are present at greater than 0.01% or greater than 0.1% by weight of the electrolyte. In some embodiments, the additional salts are present at less than 20%, less than 15%, or less than 10% by weight of the electrolyte. In some embodiments, the content of other salts is within the range formed by any two values above. Salts other than these having the above content contribute to the balance of the electrical conductivity and viscosity of the electrolytic solution.

III、负极III. Negative electrode

负极包括负极集流体和设置在所述负极集流体的一个或两个表面上的正极活性物质层，负极活性物质层包含负极活性物质。负极活性物质层可以是一层或多层，多层负极活性物质中的每层可以包含相同或不同的负极活性物质。负极活性物质为任何能够可逆地嵌入和脱嵌锂离子等金属离子的物质。在一些实施例中，负极活性物质的可充电容量大于正极活性物质的放电容量，以防止在充电期间锂金属无意地析出在负极上。The negative electrode includes a negative electrode current collector and a positive electrode active material layer disposed on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer contains the negative electrode active material. The negative electrode active material layer may be one or more layers, and each layer of the multilayer negative electrode active material may contain the same or different negative electrode active materials. The negative electrode active material is any material capable of reversibly intercalating and deintercalating metal ions such as lithium ions. In some embodiments, the chargeable capacity of the negative active material is greater than the discharge capacity of the positive active material, so as to prevent unintentional precipitation of lithium metal on the negative electrode during charging.

作为保持负极活性物质的集流体，可以任意使用公知的集流体。负极集流体的实例包括，但不限于，铝、铜、镍、不锈钢、镀镍钢等金属材料。在一些实施例中，负极集流体为铜。As the current collector holding the negative electrode active material, any known current collector can be used arbitrarily. Examples of negative electrode current collectors include, but are not limited to, metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. In some embodiments, the negative current collector is copper.

在负极集流体为金属材料的情况下，负极集流体形式可包括，但不限于，金属箔、金属圆柱、金属带卷、金属板、金属薄膜、金属板网、冲压金属、发泡金属等。在一些实施例中，负极集流体为金属薄膜。在一些实施例中，负极集流体为铜箔。在一些实施例中，负极集流体为基于压延法的压延铜箔或基于电解法的电解铜箔。When the negative electrode current collector is a metal material, the form of the negative electrode current collector may include, but not limited to, metal foil, metal cylinder, metal strip, metal plate, metal film, expanded metal, stamped metal, foamed metal, etc. In some embodiments, the negative electrode current collector is a metal film. In some embodiments, the negative electrode current collector is copper foil. In some embodiments, the negative electrode current collector is a rolled copper foil based on a rolling method or an electrolytic copper foil based on an electrolytic method.

在一些实施例中，负极集流体的厚度为大于1μm或大于5μm。在一些实施例中，负极集流体的厚度为小于100μm或小于50μm。在一些实施例中，负极集流体的厚度在上述任意两个数值所组成的范围内。In some embodiments, the thickness of the negative electrode current collector is greater than 1 μm or greater than 5 μm. In some embodiments, the thickness of the negative electrode current collector is less than 100 μm or less than 50 μm. In some embodiments, the thickness of the negative electrode current collector is within the range formed by any two values above.

负极活性物质没有特别限制，只要能够可逆地吸藏、放出锂离子即可。负极活性物质的实例可包括，但不限于，天然石墨、人造石墨等碳材料；硅(Si)、锡(Sn)等金属；或Si、Sn等金属元素的氧化物等。负极活性物质可以单独使用或组合使用。The negative electrode active material is not particularly limited as long as it can reversibly store and release lithium ions. Examples of negative electrode active materials may include, but are not limited to, carbon materials such as natural graphite and artificial graphite; metals such as silicon (Si) and tin (Sn); or oxides of metal elements such as Si and Sn. The negative electrode active materials can be used alone or in combination.

负极活性物质层还可包括负极粘合剂。负极粘合剂可提高负极活性物质颗粒彼此间的结合和负极活性物质与集流体的结合。负极粘合剂的种类没有特别限制，只要是对于电解液或电极制造时使用的溶剂稳定的材料即可。在一些实施例中，负极粘合剂包括树脂粘合剂。树脂粘合剂的实例包括，但不限于，氟树脂、聚丙烯腈(PAN)、聚酰亚胺树脂、丙烯酸系树脂、聚烯烃树脂等。当使用水系溶剂制备负极合剂浆料时，负极粘合剂包括，但不限于，羧甲基纤维素(CMC)或其盐、苯乙烯-丁二烯橡胶(SBR)、聚丙烯酸(PAA)或其盐、聚乙烯醇等。The negative active material layer may further include a negative binder. The negative electrode binder can improve the combination of the negative electrode active material particles and the combination of the negative electrode active material and the current collector. The type of negative electrode binder is not particularly limited, as long as it is a material stable to the electrolyte solution or the solvent used in electrode production. In some embodiments, the negative binder includes a resin binder. Examples of resin binders include, but are not limited to, fluororesins, polyacrylonitrile (PAN), polyimide resins, acrylic resins, polyolefin resins, and the like. When using a water-based solvent to prepare the negative electrode mixture slurry, the negative electrode binder includes, but is not limited to, carboxymethyl cellulose (CMC) or its salt, styrene-butadiene rubber (SBR), polyacrylic acid (PAA) or Its salt, polyvinyl alcohol, etc.

负极可以通过以下方法制备：在负极集流体上涂布包含负极活性物质、树脂粘合剂等的负极合剂浆料，干燥后，进行压延而在负极集流体的两面形成负极活性物质层，由此可以得到负极。The negative electrode can be prepared by the following method: coating the negative electrode mixture slurry comprising negative electrode active material, resin binder, etc. on the negative electrode current collector, after drying, calendering to form negative electrode active material layers on both sides of the negative electrode current collector, thus Negative pole is available.

IV、隔离膜IV. Isolation film

为了防止短路，在正极与负极之间通常设置有隔离膜。这种情况下，本申请的电解液通常渗入该隔离膜而使用。In order to prevent a short circuit, a separator is usually provided between the positive electrode and the negative electrode. In this case, the electrolytic solution of the present application is usually used by permeating the separator.

对隔离膜的材料及形状没有特别限制，只要不显著损害本申请的效果即可。所述隔离膜可为由对本申请的电解液稳定的材料所形成的树脂、玻璃纤维、无机物等。在一些实施例中，所述隔离膜包括保液性优异的多孔性片或无纺布状形态的物质等。树脂或玻璃纤维隔离膜的材料的实例可包括，但不限于，聚烯烃、芳香族聚酰胺、聚四氟乙烯、聚醚砜等。在一些实施例中，所述聚烯烃为聚乙烯或聚丙烯。在一些实施例中，所述聚烯烃为聚丙烯。上述隔离膜的材料可以单独使用或任意组合使用。The material and shape of the separator are not particularly limited as long as the effect of the present application is not significantly impaired. The separator can be resin, glass fiber, inorganic material, etc. formed of materials stable to the electrolyte solution of the present application. In some embodiments, the separator includes a porous sheet or a non-woven fabric-like substance with excellent liquid retention properties. Examples of the material of the resin or fiberglass separator may include, but are not limited to, polyolefin, aramid, polytetrafluoroethylene, polyethersulfone, and the like. In some embodiments, the polyolefin is polyethylene or polypropylene. In some embodiments, the polyolefin is polypropylene. The materials for the above separators may be used alone or in any combination.

所述隔离膜还可为上述材料层积而成的材料，其实例包括，但不限于，按照聚丙烯、聚乙烯、聚丙烯的顺序层积而成的三层隔离膜等。The isolation film can also be a material formed by laminating the above materials, examples of which include, but not limited to, a three-layer isolation film formed by laminating polypropylene, polyethylene, and polypropylene in this order.

无机物的材料的实例可包括，但不限于，氧化铝、二氧化硅等氧化物、氮化铝、氮化硅等氮化物、硫酸盐(例如，硫酸钡、硫酸钙等)。无机物的形式可包括，但不限于，颗粒状或纤维状。Examples of materials of inorganic substances may include, but are not limited to, oxides such as aluminum oxide and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, sulfates (eg, barium sulfate, calcium sulfate, etc.). Inorganic forms may include, but are not limited to, granular or fibrous.

所述隔离膜的形态可为薄膜形态，其实例包括，但不限于，无纺布、织布、微多孔性膜等。在薄膜形态中，所述隔离膜的孔径为0.01μm至1μm，厚度为5 μm至50μm。除了上述独立的薄膜状隔离膜以外，还可以使用下述隔离膜：通过使用树脂类的粘合剂在正极和/或负极的表面形成含有上述无机物颗粒的复合多孔层而形成的隔离膜，例如，将氟树脂作为粘合剂使90％粒径小于1μm的氧化铝颗粒在正极的两面形成多孔层而形成的隔离膜。The form of the separator may be in the form of a film, examples of which include, but are not limited to, non-woven fabrics, woven fabrics, microporous films, and the like. In thin film form, the pore diameter of the isolation membrane is 0.01 μm to 1 μm, and the thickness is 5 μm to 50 μm. In addition to the above-mentioned independent film-shaped separator, the following separator can also be used: a separator formed by forming a composite porous layer containing the above-mentioned inorganic particles on the surface of the positive electrode and/or negative electrode using a resin-based binder, For example, a separator is formed by using a fluororesin as a binder to form porous layers on both sides of the positive electrode with 90% of the alumina particles having a particle size of less than 1 μm.

所述隔离膜的厚度是任意的。在一些实施例中，所述隔离膜的厚度为大于1μm、大于5μm或大于8μm。在一些实施例中，所述隔离膜的厚度为小于50μm、小于40μm或小于30μm。在一些实施例中，所述隔离膜的厚度在上述任意两个数值所组成的范围内。当所述隔离膜的厚度在上述范围内时，则可以确保绝缘性和机械强度，并可以确保电化学装置的倍率特性和能量密度。The thickness of the separator is arbitrary. In some embodiments, the thickness of the isolation film is greater than 1 μm, greater than 5 μm, or greater than 8 μm. In some embodiments, the thickness of the isolation film is less than 50 μm, less than 40 μm or less than 30 μm. In some embodiments, the thickness of the isolation film is within the range formed by any two values above. When the thickness of the separator is within the above range, insulation and mechanical strength can be ensured, and rate characteristics and energy density of the electrochemical device can be ensured.

在使用多孔性片或无纺布等多孔质材料作为隔离膜时，隔离膜的孔隙率是任意的。在一些实施例中，所述隔离膜的孔隙率为大于10％、大于15％或大于20％。在一些实施例中，所述隔离膜的孔隙率为小于60％、小于50％或小于45％。在一些实施例中，所述隔离膜的孔隙率在上述任意两个数值所组成的范围内。当所述隔离膜的孔隙率在上述范围内时，可以确保绝缘性和机械强度，并可以抑制膜电阻，使电化学装置具有良好的安全特性。When a porous material such as a porous sheet or nonwoven fabric is used as the separator, the porosity of the separator is arbitrary. In some embodiments, the isolation membrane has a porosity greater than 10%, greater than 15%, or greater than 20%. In some embodiments, the separator has a porosity of less than 60%, less than 50%, or less than 45%. In some embodiments, the porosity of the isolation membrane is within the range formed by any two values above. When the porosity of the separator is within the above range, insulation and mechanical strength can be ensured, and membrane resistance can be suppressed, so that the electrochemical device has good safety characteristics.

所述隔离膜的平均孔径也是任意的。在一些实施例中，所述隔离膜的平均孔径为小于0.5μm或小于0.2μm。在一些实施例中，所述隔离膜的平均孔径为大于0.05μm。在一些实施例中，所述隔离膜的平均孔径在上述任意两个数值所组成的范围内。若所述隔离膜的平均孔径超过上述范围，则容易发生短路。当隔离膜的平均孔径在上述范围内时，使电化学装置具有良好的安全特性。The average pore diameter of the separator is also arbitrary. In some embodiments, the average pore size of the isolation membrane is less than 0.5 μm or less than 0.2 μm. In some embodiments, the average pore size of the isolation membrane is greater than 0.05 μm. In some embodiments, the average pore diameter of the isolation membrane is within the range formed by any two values above. When the average pore diameter of the separator exceeds the above-mentioned range, short circuits are likely to occur. When the average pore diameter of the isolation membrane is within the above range, the electrochemical device has good safety characteristics.

V、电化学装置组件V. Electrochemical device components

电化学装置组件包括电极组、集电结构、外装壳体和保护元件。The electrochemical device assembly includes an electrode group, a current collecting structure, an outer casing and a protection element.

电极组可以是由上述正极和负极隔着上述隔离膜层积而成的层积结构、以及上述正极和负极隔着上述隔离膜以漩涡状卷绕而成的结构中的任一种。在一些实施例中，电极组的质量在电池内容积中所占的比例(电极组占有率)为大于40％或大于50％。在一些实施例中，电极组占有率为小于90％或小于80％。在一些实施例中，电极组占有率在上述任意两个数值所组成的范围内。当电极组占有率在上述范围内时，可以确保电化学装置的容量，同时可以抑制与内部压力上升相伴的反复充放电性能及高温保存等特性的降低。The electrode group may have either a laminated structure in which the positive electrode and the negative electrode are laminated with the separator interposed therebetween, or a structure in which the positive electrode and the negative electrode are wound in a spiral shape with the separator interposed therebetween. In some embodiments, the ratio of the mass of the electrode group to the internal volume of the battery (electrode group occupancy) is greater than 40% or greater than 50%. In some embodiments, the electrode set occupancy is less than 90% or less than 80%. In some embodiments, the occupancy of the electrode group is within the range formed by any two values above. When the electrode group occupancy ratio is within the above range, the capacity of the electrochemical device can be ensured, and at the same time, the decrease in characteristics such as repeated charge-discharge performance and high-temperature storage due to an increase in internal pressure can be suppressed.

集电结构没有特别限制。在一些实施例中，集电结构为降低配线部分及接合部分的电阻的结构。当电极组为上述层积结构时，适合使用将各电极层的金属芯部分捆成束而焊接至端子上所形成的结构。一片的电极面积增大时，内部电阻增大，因而在电极内设置2个以上的端子而降低电阻也是适合使用的。当电极组为上述卷绕结构时，通过在正极和负极分别设置2个以上的引线结构，并在端子上捆成束，从而可以降低内部电阻。The current collecting structure is not particularly limited. In some embodiments, the current collecting structure is a structure that reduces the resistance of the wiring portion and the bonding portion. When the electrode group has the above-mentioned laminated structure, it is suitable to use a structure in which the metal core portions of the electrode layers are bundled and welded to the terminal. When the area of one electrode increases, the internal resistance increases, so it is also suitable to provide two or more terminals in the electrode to reduce the resistance. When the electrode group has the above-mentioned winding structure, the internal resistance can be reduced by providing two or more lead wire structures on the positive electrode and the negative electrode respectively, and bundling them on the terminals.

外装壳体的材质没有特别限制，只要是对于所使用的电解液稳定的物质即可。外装壳体可使用，但不限于，镀镍钢板、不锈钢、铝或铝合金、镁合金等金属类、或者树脂与铝箔的层积膜。在一些实施例中，外装壳体为铝或铝合金的金属或层积膜。The material of the outer case is not particularly limited, as long as it is stable to the electrolyte solution used. As the exterior case, metals such as nickel-plated steel sheets, stainless steel, aluminum or aluminum alloys, and magnesium alloys, or laminated films of resin and aluminum foil can be used, but not limited to. In some embodiments, the outer casing is aluminum or aluminum alloy metal or a laminated film.

金属类的外装壳体包括，但不限于，通过激光焊接、电阻焊接、超声波焊接将金属彼此熔敷而形成的封装密闭结构；或者隔着树脂制垫片使用上述金属类形成的铆接结构。使用上述层积膜的外装壳体包括，但不限于，通过将树脂层彼此热粘而形成的封装密闭结构等。为了提高密封性，还可以在上述树脂层之间夹入与层积膜中所用的树脂不同的树脂。在通过集电端子将树脂层热粘而形成密闭结构时，由于金属与树脂的接合，可使用具有极性基团的树脂或导入了极性基团的改性树脂作为夹入的树脂。另外，外装体的形状也是任意的，例如可以为圆筒形、方形、层积型、纽扣型、大型等中的任一种。Metal exterior cases include, but are not limited to, encapsulation and sealing structures formed by welding metals together by laser welding, resistance welding, or ultrasonic welding; or riveted structures using the above-mentioned metals through resin spacers. The exterior case using the above-mentioned laminated film includes, but is not limited to, a package sealing structure formed by thermally bonding resin layers to each other, and the like. In order to improve the sealability, a resin different from the resin used in the laminated film may be interposed between the above-mentioned resin layers. When the resin layer is thermally bonded through the collector terminal to form a sealed structure, a resin having a polar group or a modified resin into which a polar group is introduced can be used as the interposed resin due to the bonding between the metal and the resin. In addition, the shape of the exterior body is also arbitrary, and for example, any of cylindrical, square, laminated, button-shaped, large, and the like may be used.

保护元件可以使用在异常放热或过大电流流过时电阻增大的正温度系数(PTC)、温度熔断器、热敏电阻、在异常放热时通过使电池内部压力或内部温度急剧上升而切断在电路中流过的电流的阀(电流切断阀)等。上述保护元件可选择在高电流的常规使用中不工作的条件的元件，亦可设计成即使不存在保护元件也不至于发生异常放热或热失控的形式。Protection elements can use positive temperature coefficient (PTC) whose resistance increases when abnormal heat generation or excessive current flows, temperature fuses, thermistors, cut off by causing the internal pressure of the battery or the internal temperature to rise sharply at the time of abnormal heat generation A valve (current cut-off valve) for the current flowing in the circuit, etc. The above-mentioned protection elements can be selected under the condition that they do not work in the normal use of high current, and can also be designed in such a way that abnormal heat dissipation or thermal runaway will not occur even if there is no protection element.

本申请的电化学装置包括发生电化学反应的任何装置，它的具体实例包括锂金属二次电池或锂离子二次电池。The electrochemical device of the present application includes any device that undergoes an electrochemical reaction, and specific examples thereof include a lithium metal secondary battery or a lithium ion secondary battery.

本申请另提供了一种电子装置，其包括根据本申请所述的电化学装置。The present application further provides an electronic device, which includes the electrochemical device according to the present application.

本申请的电化学装置的用途没有特别限定，其可用于现有技术中已知的任何电子装置。在一些实施例中，本申请的电化学装置可用于，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、家庭用大型蓄电池和锂离子电容器等。The application of the electrochemical device of the present application is not particularly limited, and it can be used in any electronic device known in the prior art. In some embodiments, the electrochemical device of the present application can be used in, but not limited to, notebook computers, pen-based computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-worn Stereo headphones, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, power assist Bicycles, bicycles, lighting equipment, toys, game consoles, clocks, electric tools, flashlights, cameras, large household storage batteries and lithium-ion capacitors, etc.

下面以锂离子电池为例并且结合具体的实施例说明锂离子电池的制备，本领域的技术人员将理解，本申请中描述的制备方法仅是实例，其他任何合适的制备方法均在本申请的范围内。The lithium ion battery is taken as an example below and the preparation of the lithium ion battery is described in conjunction with specific examples. Those skilled in the art will understand that the preparation method described in this application is only an example, and any other suitable preparation methods are described in this application. within range.

实施例Example

一、锂离子电池的制备1. Preparation of lithium ion battery

1、负极的制备1. Preparation of negative electrode

将人造石墨、丁苯橡胶和羧甲基纤维素钠按照96％:2％:2％的质量比例与去离子水混合，搅拌均匀，得到负极浆料。将该负极浆料涂布在9μm的铜箔上，干燥，冷压，再经过裁片、焊接极耳，得到负极。Mix artificial graphite, styrene-butadiene rubber and sodium carboxymethyl cellulose with deionized water in a mass ratio of 96%:2%:2%, and stir evenly to obtain negative electrode slurry. The negative electrode slurry was coated on a 9 μm copper foil, dried, cold pressed, cut into pieces, and tabs were welded to obtain a negative electrode.

2、正极的制备2. Preparation of positive electrode

将钴酸锂(杉杉LC9000E)、Super-P和聚偏氟乙烯按照97:1:2的质量比例与N-甲基吡咯烷酮(NMP)混合，再加入聚(酰胺酸)(化学式I-1，其中化学式I-1a中n＝5、化学式I-1b中n＝10、化学式I-1c中n＝15、化学式I-1d中n＝20)，搅拌均匀，得到正极浆料。将该正极浆料涂布在12μm的铝箔上，干燥，冷压，再经过裁片、焊接极耳，得到正极。Lithium cobaltate (Shanshan LC9000E), Super-P and polyvinylidene fluoride are mixed with N-methylpyrrolidone (NMP) according to the mass ratio of 97:1:2, and then poly(amic acid) (chemical formula I-1 , wherein n=5 in the chemical formula I-1a, n=10 in the chemical formula I-1b, n=15 in the chemical formula I-1c, n=20 in the chemical formula I-1d), and stirred evenly to obtain the positive electrode slurry. The positive electrode slurry was coated on a 12 μm aluminum foil, dried, cold pressed, cut into pieces, and tabs were welded to obtain a positive electrode.

3、电解液的制备3. Preparation of electrolyte

在干燥氩气环境下，将EC、PC和DEC(重量比1:1:1)混合，加入LiPF ₆混合均匀，形成基础电解液，其中LiPF ₆的浓度为12.5％。在基础电解液中加入不同含量添加剂得到不同实施例和对比例的电解液。 In a dry argon environment, EC, PC and DEC (weight ratio 1:1:1) were mixed, and LiPF ₆ was added to mix well to form a basic electrolyte, in which the concentration of LiPF ₆ was 12.5%. The electrolytes of different examples and comparative examples were obtained by adding additives with different contents into the basic electrolyte.

电解液中组分的缩写及其名称如下表所示：The abbreviations and names of the components in the electrolyte are shown in the table below:

材料名称material name	缩写abbreviation	材料名称material name	缩写abbreviation
碳酸乙烯酯Vinyl carbonate	ECEC	碳酸丙烯酯Propylene carbonate	PCPC
碳酸二乙酯diethyl carbonate	DECDEC	式II-1化合物Compound of formula II-1	式II-1Formula II-1
式II-2化合物Compound of formula II-2	式II-2Formula II-2	式II-3化合物Compound of formula II-3	式II-3Formula II-3
式II-4化合物Compound of formula II-4	式II-4Formula II-4	式II-5化合物Compound of formula II-5	式II-5Formula II-5
式II-6化合物Compound of formula II-6	式II-6Formula II-6	式II-7化合物Compound of formula II-7	式II-7Formula II-7
式II-8化合物Compound of formula II-8	式II-8Formula II-8	式II-9化合物Compound of formula II-9	式II-9Formula II-9
1,3-丙磺酸内酯1,3-Propane sultone	PSP.S.	硫酸乙烯酯vinyl sulfate	DTDDTD
式III-1化合物Compound of formula III-1	式III-1Formula III-1	式III-3化合物Compound of formula III-3	式III-3Formula III-3

式III-4化合物Compound of formula III-4

式III-4Formula III-4

the

4、隔离膜的制备4. Preparation of isolation membrane

以聚乙烯多孔聚合物薄膜作为隔离膜。A polyethylene porous polymer film is used as a separator.

5、锂离子电池的制备5. Preparation of Li-ion battery

将得到的正极、隔离膜和负极按次序卷绕，置于外包装箔中，留下注液口。从注液口灌注电解液，封装，再经过化成、容量等工序制得锂离子电池。Wind the obtained positive electrode, separator and negative electrode in sequence, place them in the outer packaging foil, and leave a liquid injection port. The electrolyte solution is poured from the liquid injection port, packaged, and then the lithium-ion battery is produced through processes such as formation and capacity.

二、测试方法2. Test method

1、锂离子电池的高温短路变形率的测试方法1. Test method of high temperature short circuit deformation rate of lithium ion battery

在25℃下，将锂离子电池静置30分钟，然后以0.5C倍率恒流充电至4.7V，再在4.7V下恒压充电至0.05C，静置60分钟，测量锂离子电池的厚度T ₁。然后以100mΩ使锂离子电池短路10秒钟，然后测量锂离子电池的厚度T ₂。通过下式计算锂离子电池高温短路变形率： At 25°C, let the lithium-ion battery stand still for 30 minutes, then charge it to 4.7V with a constant current at a rate of 0.5C, then charge it at a constant voltage at 4.7V to 0.05C, let it stand for 60 minutes, and measure the thickness T of the lithium-ion battery ₁ . The lithium-ion battery was then short-circuited at 100 mΩ for 10 seconds, and then the thickness T ₂ of the lithium-ion battery was measured. The high-temperature short-circuit deformation rate of lithium-ion batteries is calculated by the following formula:

短路变形率＝[(T ₂-T ₁)/T ₁]×100％。 Short-circuit deformation rate=[(T ₂ -T ₁ )/T ₁ ]×100%.

2、锂离子电池过充变形率的测试方法2. Test method for overcharge deformation rate of lithium ion battery

在25℃下，将锂离子电池静置30分钟，然后以0.5C倍率恒流充电至4.7V，再在4.7V下恒压充电至0.05C，静置60分钟，测量锂离子电池的厚度H ₁。然后将锂离子电池以0.1C倍率恒流充电60分钟，静置30分钟，重复这一步骤5次，使锂离子电池达到150％荷电状态(SOC)，测量锂离子电池的厚度H ₂。通过下式计算锂离子电池的过充变形率： At 25°C, let the lithium-ion battery stand still for 30 minutes, then charge it to 4.7V with a constant current at a rate of 0.5C, then charge it at a constant voltage at 4.7V to 0.05C, let it stand for 60 minutes, and measure the thickness H of the lithium-ion battery ₁ . Then charge the lithium-ion battery with a constant current at a rate of 0.1C for 60 minutes, let it stand for 30 minutes, repeat this step 5 times to make the lithium-ion battery reach 150% state of charge (SOC), and measure the thickness H ₂ of the lithium-ion battery. Calculate the overcharge deformation rate of the lithium-ion battery by the following formula:

过充变形率＝[(H ₂-H ₁)/H ₁]×100％。 Overcharge deformation rate=[(H ₂ -H ₁ )/H ₁ ]×100%.

3、锂离子电池高温高压下浮充性能的测试方法3. Test method for floating charge performance of lithium-ion batteries under high temperature and high pressure

在25℃下，将锂离子电池以0.5C恒流充电至4.7V，再在4.7V下恒压充电至0.05C。然后将锂离子电池置于50℃烘箱中，以4.7V持续恒压充电(截至电流为20mA)，监控锂离子电池的厚度的变化。以初始50％充电状态(SOC)时锂离子电池的厚度作为基准，当锂离子电池厚度增加超过20％时记为失效。记录锂离子电池在50℃下浮充至失效的时间，以小时(h)作为统计单位。At 25°C, the Li-ion battery was charged at a constant current of 0.5C to 4.7V, and then charged at a constant voltage of 4.7V to 0.05C. Then, the lithium-ion battery was placed in an oven at 50° C., continuously charged at a constant voltage of 4.7 V (the cut-off current was 20 mA), and the thickness change of the lithium-ion battery was monitored. Taking the thickness of the lithium-ion battery at the initial 50% state of charge (SOC) as a benchmark, when the thickness of the lithium-ion battery increases by more than 20%, it is recorded as failure. Record the time from float charge to failure of the lithium-ion battery at 50°C, in hours (h) as the statistical unit.

三、测试结果3. Test results

表1展示了正极活性物质和电解液对锂离子电池的浮充性能和安全性的影响，其中二氟亚磷酸酯化合物为式II-1化合物。Table 1 shows the impact of the positive electrode active material and electrolyte on the float performance and safety of the lithium-ion battery, wherein the difluorophosphite compound is the compound of formula II-1.

表1Table 1

如对比例1-1所示，虽然电解液包括二氟亚磷酸酯化合物，但正极活性物质不包括聚(酰胺酸)，锂离子电池的过充变形率和短路变形率较高且浮充失效时间较短。如对比例1-2所示，虽然正极活性物质包括聚(酰胺酸)，但电解液不包括二氟亚磷酸酯化合物，锂离子电池的过充变形率和短路变形率较高且浮充失效时间较短。As shown in Comparative Example 1-1, although the electrolyte includes a difluorophosphite compound, but the positive electrode active material does not include poly(amic acid), the overcharge deformation rate and short circuit deformation rate of the lithium-ion battery are high and the float charge fails. The time is shorter. As shown in Comparative Examples 1-2, although the positive electrode active material includes poly(amic acid), but the electrolyte does not include difluorophosphite compounds, the overcharge deformation rate and short circuit deformation rate of the lithium ion battery are high and the float charge failure The time is shorter.

如实施例1-1至1-17所示，当正极活性物质包括聚(酰胺酸)且电解液包括二氟亚磷酸酯化合物时，可显著降低锂离子电池的过充变形率和短路变形率并显著提升其浮充失效时间。不同结构的聚(酰胺酸)可实现基本相当的效果。As shown in Examples 1-1 to 1-17, when the positive electrode active material includes poly(amic acid) and the electrolyte includes a difluorophosphite compound, the overcharge deformation rate and short circuit deformation rate of the lithium-ion battery can be significantly reduced And significantly improve its floating charge failure time. Poly(amic acid)s of different structures can achieve substantially equivalent effects.

此外，当正极活性物质层中聚(酰胺酸)的含量a％与电解液中二氟亚磷酸酯化合物的含量b％满足0.1≤a/b≤5时，可进一步降低锂离子电池的过充变形率和短路变形率并提升其浮充失效时间。In addition, when the content a% of the poly(amic acid) in the positive electrode active material layer and the content b% of the difluorophosphite compound in the electrolyte meet 0.1≤a/b≤5, the overcharge of the lithium-ion battery can be further reduced Deformation rate and short-circuit deformation rate and increase its floating charge failure time.

当正极活性物质层中聚(酰胺酸)的含量在0.5％-5％的范围内时，可进一步降低锂离子电池的过充变形率和短路变形率并提升其浮充失效时间。When the content of poly(amic acid) in the positive electrode active material layer is in the range of 0.5%-5%, it can further reduce the overcharge deformation rate and short circuit deformation rate of the lithium ion battery and improve its floating charge failure time.

当电解液中二氟亚磷酸酯化合物的含量在0.1％至5％的范围内时，可进一步降低锂离子电池的过充变形率和短路变形率并提升其浮充失效时间。When the content of the difluorophosphite compound in the electrolyte is in the range of 0.1% to 5%, the overcharge deformation rate and short circuit deformation rate of the lithium ion battery can be further reduced and the floating charge failure time can be improved.

表2展示了不同结构二氟亚磷酸酯化合物对锂离子电池的浮充性能和安全性的影响。除表2中所列参数以外，实施例2-1至2-8与实施例1-1的设置相同。Table 2 shows the effect of difluorophosphite compounds with different structures on the float performance and safety of lithium-ion batteries. Except for the parameters listed in Table 2, the settings of Examples 2-1 to 2-8 are the same as those of Example 1-1.

表2Table 2

the	二氟亚磷酸酯化合物Difluorophosphite compound	过充变形率(％)Overcharge deformation rate (%)	短路变形率(％)Short circuit deformation rate (%)	浮充失效时间(h)Float charge failure time (h)
实施例1-1Example 1-1	式II-1Formula II-1	16.916.9	17.817.8	805805
实施例2-1Example 2-1	式II-2Formula II-2	15.315.3	16.416.4	835835
实施例2-2Example 2-2	式II-3Formula II-3	15.215.2	16.516.5	842842
实施例2-3Example 2-3	式II-4Formula II-4	15.315.3	16.216.2	879879
实施例2-4Example 2-4	式II-5Formula II-5	12.312.3	12.612.6	10061006
实施例2-5Example 2-5	式II-6Formula II-6	11.611.6	11.911.9	10211021
实施例2-6Example 2-6	式II-7Formula II-7	13.713.7	12.512.5	978978
实施例2-7Example 2-7	式II-8Formula II-8	13.213.2	12.112.1	993993
实施例2-8Example 2-8	式II-9Formula II-9	12.612.6	11.811.8	10681068

结果表明，不同结构的二氟亚磷酸酯化合物可实现基本相当的效果。当二氟亚磷酸酯化合物中含有醚键(实施例2-4、2-5和2-8)时，可进一步降低锂离子电池的过充变形率和短路变形率并提升其浮充失效时间。The results show that difluorophosphite compounds with different structures can achieve substantially equivalent effects. When containing ether bond (embodiment 2-4, 2-5 and 2-8) in the difluorophosphite compound, can further reduce the overcharge deformation rate and the short circuit deformation rate of lithium-ion battery and improve its floating charge failure time .

表3展示了含硫氧双键化合物对锂离子电池的浮充性能和安全性的影响，其中电解液中含硫氧双键化合物的含量为1％。除表3中所列参数以外，实施例3-1至3-5与实施例1-1的设置相同。Table 3 shows the influence of the sulfur-oxygen double bond compound on the float performance and safety of the lithium-ion battery, wherein the content of the sulfur-oxygen double bond compound in the electrolyte is 1%. Except for the parameters listed in Table 3, the settings of Examples 3-1 to 3-5 are the same as those of Example 1-1.

表3table 3

the	含硫氧双键化合物Compounds containing sulfur and oxygen double bonds	过充变形率(％)Overcharge deformation rate (%)	短路变形率(％)Short circuit deformation rate (%)	浮充失效时间(h)Float charge failure time (h)
实施例1-1Example 1-1	——	16.916.9	17.817.8	805805
实施例3-1Example 3-1	PSP.S.	13.613.6	14.514.5	815815
实施例3-2Example 3-2	DTDDTD	13.213.2	14.214.2	811811
实施例3-3Example 3-3	式III-1Formula III-1	13.713.7	14.814.8	823823
实施例3-4Example 3-4	式III-3Formula III-3	11.511.5	11.911.9	895895
实施例3-5Example 3-5	式III-4Formula III-4	11.211.2	10.510.5	11241124

结果表明，当电解液进一步包括含硫氧双键化合物时，可进一步降低锂离子电池的过充变形率和短路变形率并提升其浮充失效时间。The results show that when the electrolyte further includes a sulfur-oxygen double bond compound, the overcharge deformation rate and short circuit deformation rate of the lithium-ion battery can be further reduced and its floating charge failure time can be improved.

表4展示了电解液中二氟亚磷酸酯化合物和含硫氧双键化合物的含量关系对锂离子电池的浮充性能和安全性的影响。除表4中所列参数以外，实施例4-1 至4-9与实施例1-1的设置相同。Table 4 shows the effect of the content relationship between the difluorophosphite compound and the sulfur-oxygen double bond compound in the electrolyte on the float performance and safety of the lithium-ion battery. Except for the parameters listed in Table 4, the settings of Examples 4-1 to 4-9 are the same as those of Example 1-1.

表4Table 4

结果表明，当电解液中二氟亚磷酸酯化合物的含量b％与含硫氧双键化合物的含量c％满足1≤b+c≤8和0.4≤b/c≤5时，可进一步降低锂离子电池的过充变形率和短路变形率并提升其浮充失效时间。The results show that when the content b% of the difluorophosphite compound and the content c% of the sulfur-oxygen double bond compound in the electrolyte satisfy 1≤b+c≤8 and 0.4≤b/c≤5, the lithium can be further reduced The overcharge deformation rate and short circuit deformation rate of the ion battery and improve its floating charge failure time.

整个说明书中对“实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用，其所代表的意思是在本申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此，在整个说明书中的各处所出现的描述，例如：“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”，“在一个举例中”、“在特定举例中”或“举例”，其不必然是引用本申请中的相同的实施例或示例。此外，本文中的特定特征、结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。References to "embodiment", "partial embodiment", "an embodiment", "another example", "example", "specific example" or "partial example" in the entire specification mean that At least one embodiment or example in the present application includes a specific feature, structure, material or characteristic described in the embodiment or example. Thus, descriptions that appear throughout the specification such as: "in some embodiments", "in an embodiment", "in one embodiment", "in another example", "in an example In", "in a particular example" or "example", they are not necessarily referring to the same embodiment or example in this application. Furthermore, the particular features, structures, materials, or characteristics herein may be combined in any suitable manner in one or more embodiments or examples.

尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。Although illustrative embodiments have been shown and described, those skilled in the art should understand that the foregoing embodiments are not to be construed as limitations on the present application, and that changes may be made in the embodiments without departing from the spirit, principle and scope of the application. , substitution and modification.

Claims

一种电化学装置，其包括：正极、负极和电解液，所述正极包括正极集流体和形成在所述正极集流体上的正极活性物质层，其中：An electrochemical device comprising: a positive electrode, a negative electrode and an electrolyte, the positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector, wherein:

所述正极活性物质层包括聚(酰胺酸)，并且The positive active material layer includes poly(amic acid), and

所述电解液包括二氟亚磷酸酯化合物。The electrolytic solution includes a difluorophosphite compound.
根据权利要求1所述的电化学装置，其中：The electrochemical device according to claim 1, wherein:

基于所述正极活性物质层的重量，所述聚(酰胺酸)的含量为a％；Based on the weight of the positive electrode active material layer, the content of the poly(amic acid) is a%;

基于所述电解液的重量，所述二氟亚磷酸酯化合物的含量为b％；且Based on the weight of the electrolyte, the content of the difluorophosphite compound is b%; and

a和b满足：0.1≤a/b≤5。a and b satisfy: 0.1≤a/b≤5.
根据权利要求2所述的电化学装置，其中a的取值范围为0.5至5。The electrochemical device according to claim 2, wherein a ranges from 0.5 to 5.
根据权利要求2所述的电化学装置，其中b的取值范围为0.1至5。The electrochemical device according to claim 2, wherein the value of b ranges from 0.1 to 5.
根据权利要求1所述的电化学装置，其中所述聚(酰胺酸)包括式I化合物：The electrochemical device according to claim 1, wherein the poly(amic acid) comprises a compound of formula I:

其中：in:

R选自C1-12烯基或C6-12芳环；R is selected from C1-12 alkenyl or C6-12 aromatic ring;

A选自单键、C1-12烯基或C6-12芳环；A is selected from single bond, C1-12 alkenyl or C6-12 aromatic ring;

n为5至20的整数。n is an integer of 5-20.
根据权利要求1所述的电化学装置，其中所述二氟亚磷酸酯化合物包括式II化合物：The electrochemical device according to claim 1, wherein the difluorophosphite compound comprises a compound of formula II:

A-OPF ₂(式II)， A-OPF ₂ (Formula II),

其中A为经取代或未经取代的C1-10烷基或C3-10环烷基；Wherein A is substituted or unsubstituted C1-10 alkyl or C3-10 cycloalkyl;

经取代时，取代基为卤素或氰基。When substituted, the substituent is halogen or cyano.
根据权利要求1所述的电化学装置，其中所述二氟亚磷酸酯化合物包括以下化合物中的至少一种：The electrochemical device according to claim 1, wherein the difluorophosphite compound comprises at least one of the following compounds:
根据权利要求1所述的电化学装置，其中所述电解液还包括含硫氧双键的化合物，所述含硫氧双键的化合物包括以下化合物中的至少一者：环状硫酸酯、链状硫酸酯、链状磺酸酯、环状磺酸酯、链状亚硫酸酯或环状亚硫酸酯或式III化合物：The electrochemical device according to claim 1, wherein the electrolytic solution further includes a compound containing a sulfur-oxygen double bond, and the compound containing a sulfur-oxygen double bond includes at least one of the following compounds: cyclic sulfate, chain Sulfate ester, chain sulfonate, cyclic sulfonate, chain sulfite or cyclic sulfite or compound of formula III:

其中：in:

W选自
W selected from

L选自单键或亚甲基；L is selected from a single bond or methylene;

m为1至4的整数；m is an integer from 1 to 4;

n为0至2的整数；且n is an integer from 0 to 2; and

p为0至6的整数。p is an integer of 0 to 6.
根据权利要求8所述的电化学装置，其中所述式III化合物选自以下中的至少一种：The electrochemical device according to claim 8, wherein the compound of formula III is selected from at least one of the following:
根据权利要求8所述的电化学装置，其中基于所述电解液的重量，所述二氟亚磷酸酯化合物的含量为b％，所述含硫氧双键的化合物的含量为c％，b和c满足：1≤b+c≤8和0.4≤b/c≤5。The electrochemical device according to claim 8, wherein based on the weight of the electrolyte, the content of the difluorophosphite compound is b%, the content of the compound containing sulfur and oxygen double bonds is c%, b and c satisfy: 1≤b+c≤8 and 0.4≤b/c≤5.
根据权利要求8所述的电化学装置，其中基于所述电解液的重量，所述含硫氧双键的化合物的含量为c％，c的取值范围为0.1至8。The electrochemical device according to claim 8, wherein based on the weight of the electrolyte, the content of the sulfur-oxygen double bond-containing compound is c%, and the value of c ranges from 0.1 to 8.
根据权利要求11所述的电化学装置，其中c的取值范围为0.1至1.5。The electrochemical device according to claim 11, wherein the value of c ranges from 0.1 to 1.5.
一种电子装置，其包括根据权利要求1-12中任一项所述的电化学装置。An electronic device comprising the electrochemical device according to any one of claims 1-12.