阅读说明：本技术 聚合物电解质、聚合物电解质层及全固态锂离子电池 (Polymer electrolyte, polymer electrolyte layer, and all-solid-state lithium ion battery ) 是由 余乐 王仁和 其他发明人请求不公开姓名 于 2021-09-08 设计创作，主要内容包括：本申请公开了一种聚合物电解质、聚合物电解质层及全固态锂离子电池。本申请中,所述聚合物电解质由式Ⅰ所示单体聚合形成,或者所述聚合物电解质由式Ⅰ所示单体与交联剂和/或寡聚物增速添加剂聚合形成。本发明第提供的聚合物电解质,采用含两个硫氧双键的结构单体,形成的聚合物更稳定。本发明提供的聚合物电解质层,柔韧性佳,导锂离子能力好。本发明提供的聚合物电解质层,在负极侧分解还原为导锂离子能力强的Li-(2)S,提高了负极锂离子的电导率。(The application discloses a polymer electrolyte, a polymer electrolyte layer and an all-solid-state lithium ion battery. In the application, the polymer electrolyte is formed by polymerizing a monomer shown in a formula I, or the polymer electrolyte is formed by polymerizing a monomer shown in the formula I and a cross-linking agent and/or an oligomer rate-increasing additive. The polymer electrolyte provided by the invention adopts the structural monomer containing two sulfur-oxygen double bonds, and the formed polymer is more stable. The polymer electrolyte layer provided by the invention has good flexibility and good lithium ion conducting capacity. The polymer electrolyte layer provided by the invention is decomposed and reduced to Li with strong lithium ion conduction capability on the negative electrode side 2 And S, the conductivity of the lithium ions of the negative electrode is improved.)

1. A polymer electrolyte is characterized in that the polymer electrolyte is formed by polymerizing a monomer shown in a formula I, or the polymer electrolyte is formed by polymerizing a monomer shown in the formula I with a cross-linking agent and/or a plasticizer,

wherein R is¹And R²Are each independently selected from C_1～20Alkyl radical, C_1～20Alkoxy radical, C_2～20Alkenyl, phenyl, pyridyl, pyrrolyl, at least one hydrogen by R^1-1Substituted C_1～20Alkyl, at least one hydrogen by R^1-1Substituted C_1～20Alkoxy, at least one hydrogen by R^1-1Substituted C_2～20Alkenyl, at least one hydrogen by R^1-1Substituted phenyl, at least one hydrogen being replaced by R^1-1Substituted pyridyl, at least one hydrogen being replaced by R^1-1Substituted pyrrolyl and

wherein R is³Is C_2～20An alkenyl group;

R^1-1selected from halogen, nitro, amino, C_1～6Alkyl radical, C_3～6Cycloalkyl radical, C_1～6An alkoxy group;

R¹and R²At least one of which has a carbon-carbon unsaturated bond;

R¹and R²At least part of a structural fragment of any one of the above may be bonded to at least part of a structural fragment of another to form a ring.

2. According to claimThe polymer electrolyte as described in 1, wherein R is¹And R²Are each independently selected from C_1～20Alkyl radical, C_1～20Alkoxy radical, C_2～20Alkenyl, at least one hydrogen by R^1-1Substituted C_1～20Alkyl, at least one hydrogen by R^1-1Substituted C_1～20Alkoxy or at least one hydrogen by R^1-1Substituted C_2～20An alkenyl group.

3. The polymer electrolyte of claim 2, wherein R is¹And R²Is not bonded to form a ring, and R¹And R²All having carbon-carbon unsaturated bonds.

4. The polymer electrolyte of claim 2, wherein R is¹Partial structural fragment of (1) and R²And bonding to form a ring.

5. The polymer electrolyte of claim 2, wherein R is¹And R²And bonding to form a ring.

6. The polymer electrolyte of claim 2, wherein the monomer of formula i has any one of the following structures:

7. the polymer electrolyte of claim 2, wherein the cross-linking agent has at least two carbon-carbon double bonds.

8. The polymer electrolyte of claim 2, wherein the cross-linking agent is selected from any one of formula II, formula III, or formula IV,

in the formula II, R₄、R₅、R₆And R₇Are each independently selected from C_1～10Alkyl orAnd R is₄、R₅、R₆And R₇At least two of which areWherein m is 0-20, X₁、X₂And X₃Each independently selected from carbon or oxygen, and X₁And X₂Not being oxygen at the same time, X₂And X₃Not being oxygen at the same time, X₁And X₃Not being oxygen at the same time;

in the formula III, n is 0 to 20, X₄、X₅And X₆Each independently selected from carbon or oxygen, and X₄And X₅Not being oxygen at the same time, X₅And X₆Not being oxygen at the same time, X₆And X₇Not being oxygen at the same time;

in the formula IV, R₈And R₉Is selected from C_1～20An alkenyl group.

9. The polymer electrolyte of claim 2, wherein the cross-linking agent is selected from at least one of 1, 6-hexanediol diacrylate, triethylene glycol diacrylate, trimethylolpropane ethoxylate triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and vinyl sulfone.

10. The polymer electrolyte of claim 2, wherein the plasticizer is selected from at least one of polyethylene glycol methacrylate, poly (ethylene glycol) diacrylate, methoxypolyethylene glycol acrylate, trimethylolpropane ethoxytriacrylate, propoxylated trimethylolpropane triacrylate, and 2, 3-epoxypropyl acrylate.

11. The polymer electrolyte of claim 2, wherein the polymerization is carried out in the presence of an initiator.

12. A method for preparing a polymer electrolyte according to any one of claims 1 to 11, wherein the method comprises:

the monomer shown in the formula I, a cross-linking agent, a plasticizer and an initiator are mixed and heated for polymerization, and the polymer is obtained.

13. The method of manufacturing according to claim 12, wherein the blending comprises: blending the monomer shown in the formula I, the cross-linking agent, the plasticizer and the initiator according to a molar ratio of a to b to c to d, wherein a is 90-98, b is 1-5, c is 0.5-3 or d is 0.1-2; and is

The temperature of the heating polymerization is 50-70 ℃;

and/or the heating polymerization time is 20-40 hours;

and/or after the heating polymerization, the preparation method further comprises purification, wherein the purification comprises vacuum drying and washing and drying.

14. The method of manufacturing according to claim 13, wherein the vacuum drying includes: putting the polymerization product into a vacuum oven, and heating for 20-30 hours at 70-90 ℃ in vacuum;

and/or, the washing and drying comprises the following steps: and washing and drying the vacuum-dried polymerization product by using deionized water and dimethyl carbonate in sequence.

15. A polymer electrolyte layer comprising the polymer electrolyte according to any one of claims 1 to 11 and a lithium salt.

16. The polymer electrolyte layer of claim 15 wherein the lithium salt is selected from lithium fluorophosphate (LiPF)₆) Lithium tetrafluoroborate (LiBF)₄) Lithium perchlorate (LiClO)₄) Lithium hexafluoroarsenate (LiAsF)₆) Lithium trifluoromethanesulfonate (LiCF)₃SO₃) Lithium tetrafluoro oxalate phosphate (litfo), lithium tris oxalate phosphate (LiTOP), lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), lithium bis (perfluoroethylsulfonyl) imide (LiFSI), (trifluoromethylsulfonyl) (n-perfluorobutylsulfonyl) imide (LiFNTFSI), lithium (fluorosulfonyl) (n-perfluorobutylsulfonyl) imide (LiFNFSI), lithium bis (LiBOB) oxalate.

17. A method for producing a polymer electrolyte layer according to claim 15, comprising:

mixing the polymer electrolyte, succinonitrile and dimethyl sulfoxide to form a polymer electrolyte solution;

dissolving a lithium salt in the polymer electrolyte solution to form a viscous liquid; and

and coating the mucus on a current collector, and drying in vacuum to form the polymer electrolyte layer.

18. The method of manufacturing of claim 17, wherein the mixing comprises: mixing the polymer electrolyte, the succinonitrile and the dimethyl sulfoxide according to the mass ratio of l to m to n, wherein l is 45-50, m is 1-5, n is 45-50, and l + m + n is 100.

19. The method according to claim 17, wherein the concentration of the lithium salt in the viscous liquid is 1 to 2 mol/L;

and/or the current collector is an aluminum foil, an aluminum plastic film (CPP) or release paper;

and/or the vacuum drying time is 18-30 hours;

and/or, the vacuum drying comprises: firstly adjusting the vacuum degree to be less than or equal to 0.1Pa, then heating up and vacuum drying, then cooling down and opening the vacuum.

20. An all solid-state lithium ion battery comprising the polymer electrolyte layer according to any one of claims 15 to 16.

Technical Field

The embodiment of the invention relates to the field of lithium ion batteries, in particular to a polymer electrolyte, a polymer electrolyte layer and an all-solid-state lithium ion battery.

Background

At present, organic carbonate electrolytes are generally adopted in commercial lithium ion batteries, but the electrolytes have the problems of easy leakage, easy combustion, easy explosion and the like, so that the safety requirements cannot be met. The all-solid-state polymer electrolyte battery has good safety performance, high energy density, wide working temperature range and long cycle life, and becomes a hotspot of research in the field of lithium ion batteries.

In the prior art, polyethylene oxide is adopted as a polymer matrix of the all-solid-state polymer electrolyte battery, but a polyethylene oxide-based system has high crystallinity and poor conductivity, and a polycarbonate compound contains a carbonate group with strong polarity inside the structure, so that the dielectric constant of an electrolyte layer is improved, and the conductivity is improved compared with that of the polyethylene oxide-based system. However, the inventors found that the polycarbonate system is incompatible with the sulfur-containing solid lithium ion battery, and the polycarbonate system has poor stability. Therefore, there is a need in the art to find a polymer electrolyte layer that is highly compatible with sulfur-containing solid state lithium ion batteries.

Disclosure of Invention

The invention aims to provide a polymer electrolyte and a polymer electrolyte layer which have good ionic conductivity, wide electrochemical window and good stability and are compatible with a sulfur-containing solid lithium ion battery.

Another object of the present invention is to provide an all solid-state lithium ion battery.

In order to solve the above technical problems, a first aspect of the present invention provides a polymer electrolyte, wherein the polymer electrolyte is formed by polymerizing a monomer represented by formula I, or formed by polymerizing a monomer represented by formula I with a crosslinking agent and/or a plasticizer,

in the formula, R¹And R²Are each independently selected from C_1～20Alkyl radical, C_1～20Alkoxy radical, C_2～20Alkenyl, phenyl, pyridyl, pyrrolyl, at least one hydrogen by R^1-1Substituted C_1～20Alkyl, at least one hydrogen by R^1-1Substituted C_1～20Alkoxy, at least one hydrogen by R^1-1Substituted C_2～20Alkenyl, at least one hydrogen by R^1-1Substituted phenyl, at least one hydrogen being replaced by R^1-1Substituted pyridyl, at least one hydrogen being replaced by R^1-1Substituted pyrrolyl and

wherein R is³Is C_2～20An alkenyl group;

R^1-1selected from halogen, nitro, amino, C_1～6Alkyl radical, C_3～6Cycloalkyl radical, C_1～6An alkoxy group;

R¹and R²At least one of which has a carbon-carbon unsaturated bond;

R¹and R²At least part of a structural fragment of any one of the above may be bonded to at least part of a structural fragment of another to form a ring.

In some preferred embodiments, R¹And R²Are each independently selected from C_1～20Alkyl radical, C_1～20Alkoxy radical, C_2～20Alkenyl, at least one hydrogen by R^1-1Substituted C_1～20Alkyl, at least one hydrogen by R^1-1Substituted C_1～20Alkoxy or at least one hydrogen by R^1-1Substituted C_2～20An alkenyl group.

In some preferred embodiments, R¹And R²Is not bonded to form a ring, and R¹And R²All having carbon-carbon unsaturated bonds.

In some preferred embodiments, R¹Partial structural fragment of (1) and R²And bonding to form a ring.

In some preferred embodiments, R¹Partial structural fragment of (1) and R²Bonded to form a ring, and the ring has carbon-carbon unsaturated bonds.

In some preferred embodiments, R¹And R²And bonding to form a ring.

In some preferred embodiments, R¹And R²Bonded to form a ring, and the ring has carbon-carbon unsaturated bonds.

In some preferred embodiments, the monomer of formula I has the structure of formula I ' -1, I ' -2, or I ' -3:

in the formula, Y₁And Y₂Each independently selected from carbon or oxygen, R¹¹And R¹²Are each independently selected from C_1～6Alkyl radical, C_1～6Alkoxy or C_2～6An alkenyl group.

In some preferred embodiments, the monomer of formula I has any one of the following structures:

in some preferred embodiments, the crosslinking agent has at least two carbon-carbon double bonds.

In some preferred embodiments, the crosslinking agent is selected from any one of formula II, formula III or formula IV,

in the formula II, R₄、R₅、R₆And R₇Are each independently selected from C_1～10Alkyl orAnd R is₄、R₅、R₆And R₇At least two of which areWherein m is 0-20, X₁、X₂And X₃Each independently selected from carbon or oxygen, and X₁And X₂Not being oxygen at the same time, X₂And X₃Not being oxygen at the same time, X₁And X₃Not being oxygen at the same time;

in the formula III, n is 0 to 20, X₄、X₅And X₆Each independently selected from carbon or oxygen, and X₄And X₅Not being oxygen at the same time, X₅And X₆Not being oxygen at the same time, X₆And X₇Not being oxygen at the same time;

in the formula IV, R₈And R₉Is selected from C_1～20An alkenyl group.

In some preferred embodiments, the cross-linking agent is selected from at least one of 1, 6-hexanediol diacrylate, triethylene glycol diacrylate, trimethylolpropane ethoxylate triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and vinyl sulfone, preferably vinyl sulfone.

In some preferred embodiments, the plasticizer is an oligomer plasticizer.

In some preferred embodiments, the plasticizer is selected from at least one of polyethylene glycol methacrylate, poly (ethylene glycol) diacrylate, methoxypolyethylene glycol acrylate, trimethylolpropane ethoxytriacrylate, propoxylated trimethylolpropane triacrylate, and 2, 3-epoxypropyl acrylate, preferably polyethylene glycol methacrylate.

In some preferred embodiments, the polymerization is carried out in the presence of an initiator.

In some preferred embodiments, the initiator is selected from at least one of Azobisisobutyronitrile (AIBN), Azobisisoheptonitrile (AIVN), dimethyl azobisisobutyrate, hydrogen peroxide, ammonium persulfate, potassium persulfate Benzoyl Peroxide (BPO), benzoyl t-butyl peroxide, or methyl ethyl ketone peroxide.

In some preferred embodiments, the preparation of the polymer electrolyte comprises the steps of:

the monomer shown in the formula I, a cross-linking agent, a plasticizer and an initiator are mixed and heated for polymerization, and the polymer is obtained.

In some preferred schemes, the molar ratio of the monomer shown in the formula I, the cross-linking agent, the plasticizer and the initiator is a: b: c: d, wherein a is 90-98, b is 1-5, c is 0.5-3 or d is 0.1-2. For example: a, b, c, d, 94:3:2.5: 0.5.

In some preferred embodiments, the temperature for the heating polymerization is 50 to 70 ℃, preferably 60 ℃.

In some preferred embodiments, the time for the heating polymerization is 20 to 40 hours, preferably 24 to 36 hours.

In some preferred embodiments, the heating polymerization further comprises purification, and the purification comprises vacuum drying and washing and drying.

In some preferred embodiments, the vacuum drying step is specifically: and (3) placing the polymerization product in a vacuum oven, and heating for 20-30 hours in vacuum at the temperature of 70-90 ℃.

In some preferred schemes, the step of washing and drying specifically comprises: and sequentially washing the vacuum-dried polymerization product by deionized water and dimethyl carbonate, and drying.

A second aspect of the present invention provides a polymer electrolyte layer comprising the polymer electrolyte and a lithium salt.

In some preferred embodiments, the preparation of the polymer electrolyte layer comprises the steps of:

(1) mixing the polymer electrolyte, succinonitrile and dimethyl sulfoxide to form a polymer electrolyte solution;

(2) dissolving a lithium salt in the polymer electrolyte solution to form a viscous liquid;

(3) and coating the mucus on a current collector, and drying in vacuum to form the polymer electrolyte layer.

In some preferred embodiments, in the polymer electrolyte solution, the mass ratio of the polymer electrolyte, the succinonitrile and the dimethyl sulfoxide is l: m: n, wherein l is 45 to 50, m is 1 to 5, n is 45 to 50, and l + m + n is 100. For example, l: m: n: 48:2: 50.

In some preferred embodiments, the solid content in the polymer electrolyte solution is 45% to 55%, for example 50%.

In some preferred embodiments, in the slime, the lithium salt is selected from lithium fluorophosphate (LiPF)₆) Lithium tetrafluoroborate (LiBF)₄) Lithium perchlorate (LiClO)₄) Lithium hexafluoroarsenate (LiAsF)₆) Lithium trifluoromethanesulfonate (LiCF)₃SO₃) Lithium tetrafluoro oxalate phosphate (litfo), lithium tris oxalate phosphate (LiTOP), lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), lithium bis (perfluoroethylsulfonyl) imide (LiFSI), (trifluoromethylsulfonyl) (n-perfluorobutylsulfonyl) imide (LiFNTFSI), lithium (fluorosulfonyl) (n-perfluorobutylsulfonyl) imide (LiFNFSI), lithium bis (LiBOB) oxalate.

In some preferred embodiments, the concentration of the lithium salt in the mucus is 1 to 2mol/L, such as 1.5 mol/L.

In some preferred embodiments, in step (3), the current collector is an aluminum foil, an aluminum plastic film CPP, or a release paper.

In order to remove the dimethyl sulfoxide sufficiently, in some preferred schemes, in the step (3), the vacuum drying time is 18-30 hours, such as 24 hours; the temperature of vacuum drying is 80-100 ℃.

In order to prevent the side reaction of the electrolyte material during vacuum drying, in some preferable schemes, during vacuum drying, the vacuum degree is firstly adjusted to be less than or equal to 0.1Pa, then the temperature is raised for vacuum drying, and then the vacuum is opened after the temperature is reduced.

A third aspect of the invention provides an all-solid lithium ion battery including the polymer electrolyte layer.

Compared with the prior art, the invention has at least the following advantages:

(1) the polymer electrolyte provided by the invention adopts the structural monomer containing two sulfur-oxygen double bonds, and the formed polymer is more stable.

(2) The polymer electrolyte layer provided by the invention has good flexibility and good lithium ion conducting capacity.

(3) The polymer electrolyte layer provided by the invention is decomposed and reduced to Li2S with strong lithium ion conducting capacity on the negative electrode side, and the conductivity of negative electrode lithium ions is improved.

(4) The polymer electrolyte layer provided by the invention has good compatibility with a sulfur-containing all-solid-state lithium ion battery.

It is to be understood that within the scope of the present invention, the above-described features of the present invention and those specifically described below (e.g., in the examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

Detailed Description

In the existing all-solid-state polymer electrolyte battery, the polymer electrolyte layer has poor conductivity and stability, and is not beneficial to use. As a result of extensive studies, the inventors have found that the use of the monomer of the present invention represented by the formula I (wherein R is¹And R²The definition of the base is described in the summary of the invention) and the polymer electrolyte layer prepared by using the polymer electrolyte formed by polymerization as a raw material has better conductivity and higher stability.

Preferably, the monomer shown in formula I and the cross-linking agent are copolymerized, so that the flexibility of the polymer electrolyte layer can be increased, the movement of lithium ions is facilitated, and the formed polymer electrolyte is used as a raw material to prepare the polymer electrolyte layer with better conductivity.

Preferably, the monomer represented by formula I and the oligomer plasticizer are copolymerized, so that the crystallinity of the obtained polymer electrolyte layer can be reduced, the flexibility of the electrolyte layer can be increased, and the conductivity of the electrolyte layer can be improved.

Preferably, the monomer shown in formula i, the cross-linking agent and the oligomer plasticizer are mixed and copolymerized, and the obtained polymer electrolyte layer can combine the advantages of the cross-linking agent and the oligomer plasticizer, so that the obtained electrolyte layer has better flexibility and higher conductivity (as in example 1).

Preferably, as the monomer represented by formula i, when a plurality of oxygens (more than two oxygens) are contained in its molecular structure, lithium ion complexing sites increase, thereby increasing the conductivity of the resulting polymer electrolyte layer.

Preferably, as the monomer represented by formula i, when its molecular structure is cyclic, its structure is more easily complexed with lithium ions, thereby increasing the conductivity of the resulting polymer electrolyte layer.

Preferably, as the cross-linking agent, when the molecular structure of the cross-linking agent contains sulfur, the cross-linking agent has better affinity with the monomer shown in the formula I, and the compatibility of the obtained polymer electrolyte layer and the solid-state lithium ion battery is increased.

Preferably, as the crosslinking agent, when the double bonds are more contained, the crosslinking sites become more, the network structure is more easily formed, and the lithium ions are more densely distributed.

Preferably, as the crosslinking agent, the less the double bonds it contains, the more flexible the polymer electrolyte and the more conductive the electrical properties are.

Term(s) for

As used herein, the term "alkyl" refers to a linear or branched saturated monovalent hydrocarbon group, wherein the alkyl group may be optionally substituted with one or more substituents. In a particular embodiment, the alkyl group is a cyclic alkyl having 1 to 20 (C)_1-20) 1 to 15 (C)_1-15) 1 to 12 (C)_1-12) 1 to 10 (C)_1-10) Or 1 to 6 (C)_1-6) Linear saturated monovalent hydrocarbon groups of carbon atoms, or having 3 to 20 (C)_3-20) 3 to 15 (C)_3-15) 3 to 12 (C)_3-12) 3 to 10 (C)_3-10) Or 3 to 6 (C)_3-6) A branched saturated monovalent hydrocarbon group of carbon atoms. Linear C as used herein_1-6And with a branched chain C_3-6Alkyl groups are also referred to as "lower alkyl". Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl (including all isomeric forms), n-propyl, isopropyl, butyl (including all isomeric forms), n-butyl, isobutyl, tert-butyl, pentyl (including all isomeric forms), and hexyl (including all isomeric forms). E.g. C_1-6The alkyl group means a linear saturated monovalent hydrocarbon group having 1 to 6 carbon atoms or a branched saturated monovalent hydrocarbon group having 3 to 6 carbon atoms.

As used herein, the term "alkenyl" refers to a linear or branched monovalent hydrocarbon group having one or more (in one embodiment, one to five) carbon-carbon double bonds. The alkenyl group may be optionally substituted with one or more substituents. It will be understood by those of ordinary skill in the art that the term "alkenyl" may also include groups having "cis" and "trans" configurations, or alternatively, "E" and "Z" configurations.

As used herein, the term "alkenyl" includes both linear and branched alkenyl groups. E.g. C_2-20Alkyl refers to a linear unsaturated monovalent hydrocarbon group having 2 to 20 carbon atoms or a branched unsaturated monovalent hydrocarbon group having 3 to 20 carbon atoms. In particular embodiments, alkenyl is a linear monovalent hydrocarbon group having 2 to 20(C2-20), 2 to 15(C2-15), 2 to 12(C2-12), 2 to 10(C2-10), or 2 to 6(C1-6) carbon atoms, or a branched monovalent hydrocarbon group having 3 to 20(C3-20), 3 to 15(C3-15), 3 to 12(C3-12), 3 to 10(C3-10), or 3 to 6(C3-6) carbon atoms. Examples of alkenyl groups include, but are not limited to, vinyl, propen-1-yl, propen-2-yl, allyl, butenyl, and 4-methylbutenyl.

As used herein, the term "alkoxy" refers to a stable straight or branched chain, or cyclic hydrocarbon group, or combinations thereof, consisting of the indicated number of carbon atoms and one or more (in one embodiment, one to three) O atoms. Examples of alkoxy groups include, but are not limited to-O-CH₃、-O-CF₃、-O-CH₂-CH₃、-O-CH₂-CH₂-CH₃、-O-CH-(CH₃)₂and-O-CH₂-CH₂-O-CH₃. In one embodiment, the alkoxy group is an optionally substituted alkoxy group described elsewhere herein.

As used herein, the term "cycloalkyl" refers to a cyclic fully or partially saturated bridged and/or unbridged hydrocarbyl group or ring system, which may be optionally substituted with one or more substituents. In a particular embodiment, the cycloalkyl group has 3 to 20 (C)_3-20) 3 to 15 (C)_3-15) 3 to 12 (C)_3-12)、3 to 10 (C)_3-10) Or 3 to 7 (C)_3-7) Carbon atoms. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, decahydronaphthyl, and adamantyl.

As used herein, the term "R¹Partial structural fragment of (1) and R²Bonded to form a ring "means that R¹At least part of with R²And bonding to form a ring. For example, when R is¹Is n-propyl group (^(γ1)CH₃-^(β1)CH₂-^(α1)CH₂-)，R²Is n-propyl group (^(γ2)CH₃-^(β2)CH₂-^(α2)CH₂-, R is¹Carbon at position beta 1 of (1) and R²The carbon at the middle gamma-2 position is bonded to form a ring, R is considered to be¹Is a partial structural segment in the n-propyl group-^(β1)CH₂-^(α1)CH₂- ", and R²(^(γ2)CH₃-^(β2)CH₂-^(α2)CH₂-) bond formation

The term "R¹And R²Bonded to form a ring "means that R¹Integer with R²The whole is bonded into a ring structure. For example, when R is¹Is n-propyl group (^(γ1)CH₃-^(β1)CH₂-^(α1)CH₂-)，R²Is n-propyl group (^(γ2)CH₃-^(β2)CH₂-^(α2)CH₂-¹And R²Bonded to form a ring "means R¹Carbon at position γ 1 of (1) and R²Formation of carbon bonding at the middle gamma 2 position

In a preferred embodiment of the present invention, the present invention provides a polymer electrolyte formed by polymerizing a monomer represented by formula I, or formed by polymerizing a monomer represented by formula I with a crosslinking agent and/or a plasticizer,

in the formula, R¹And R²Are each independently selected from C_1～20Alkyl radical, C_1～20Alkoxy radical, C_2～20Alkenyl, phenyl, pyridyl, pyrrolyl, at least one hydrogen by R^1-1Substituted C_1～20Alkyl, at least one hydrogen by R^1-1Substituted C_1～20Alkoxy, at least one hydrogen by R^1-1Substituted C_2～20Alkenyl, at least one hydrogen by R^1-1Substituted phenyl, at least one hydrogen being replaced by R^1-1Substituted pyridyl, at least one hydrogen being replaced by R^1-1Substituted pyrrolyl and

wherein R is³Is C_2～20An alkenyl group;

R^1-1selected from halogen, nitro, amino, C_1～6Alkyl radical, C_3～6Cycloalkyl radical, C_1～6An alkoxy group;

R¹and R²At least one of which has a carbon-carbon unsaturated bond;

R¹and R²At least part of a structural fragment of any one of the above may be bonded to at least part of a structural fragment of another to form a ring.

In some preferred embodiments, R¹And R²Are each independently selected from C_1～20Alkyl radical, C_1～20Alkoxy radical, C_2～20Alkenyl, at least one hydrogen by R^1-1Substituted C_1～20Alkyl, at least one hydrogen by R^1-1Substituted C_1～20Alkoxy or at least one hydrogen by R^1-1Substituted C_2～20An alkenyl group.

In some preferred embodiments, R¹And R²Is not bonded to form a ring, and R¹And R²All have carbon-carbon unsaturationAnd a key.

In some preferred embodiments, R¹Partial structural fragment of (1) and R²And bonding to form a ring.

In some preferred embodiments, R¹And R²And bonding to form a ring.

In some preferred embodiments, the monomer of formula I has any one of the following structures:

in some preferred embodiments, the crosslinking agent has at least two carbon-carbon double bonds.

In some preferred embodiments, the crosslinking agent is selected from any one of formula II, formula III or formula IV,

in the formula II, R₄、R₅、R₆And R₇Are each independently selected from C_1～10Alkyl orAnd R is₄、R₅、R₆And R₇At least two of which areWherein m is 0-20, X₁、X₂And X₃Each independently selected from carbon or oxygen, and X₁And X₂Not being oxygen at the same time, X₂And X₃Not being oxygen at the same time, X₁And X₃Not being oxygen at the same time;

in the formula III, n is 0 to 20, X₄、X₅And X₆Each independently selected from carbon or oxygen, and X₄And X₅Not being oxygen at the same time, X₅And X₆Not being oxygen at the same time, X₆And X₇Not being oxygen at the same time;

in the formula IV, R₈And R₉Is selected from C_1～20An alkenyl group.

In some preferred embodiments, the cross-linking agent is selected from at least one of 1, 6-hexanediol diacrylate, triethylene glycol diacrylate, trimethylolpropane ethoxylate triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and vinyl sulfone, preferably vinyl sulfone.

In some preferred embodiments, the plasticizer is an oligomer plasticizer.

In some preferred embodiments, the plasticizer is selected from at least one of polyethylene glycol methacrylate, poly (ethylene glycol) diacrylate, methoxypolyethylene glycol acrylate, trimethylolpropane ethoxytriacrylate, propoxylated trimethylolpropane triacrylate, and 2, 3-epoxypropyl acrylate, preferably polyethylene glycol methacrylate.

In some preferred embodiments, the polymerization is carried out in the presence of an initiator.

In some preferred embodiments, the initiator is selected from at least one of Azobisisobutyronitrile (AIBN), Azobisisoheptonitrile (AIVN), dimethyl azobisisobutyrate, hydrogen peroxide, ammonium persulfate, potassium persulfate Benzoyl Peroxide (BPO), benzoyl t-butyl peroxide, or methyl ethyl ketone peroxide.

In some preferred embodiments, the preparation of the polymer electrolyte comprises the steps of:

the monomer shown in the formula I, a cross-linking agent, a plasticizer and an initiator are mixed and heated for polymerization, and the polymer is obtained.

In some preferred schemes, the molar ratio of the monomer shown in the formula I, the cross-linking agent, the plasticizer and the initiator is a: b: c: d, wherein a is 90-98, b is 1-5, c is 0.5-3 or d is 0.1-2. For example: a, b, c, d, 94:3:2.5: 0.5.

In some preferred embodiments, the temperature for the heating polymerization is 50 to 70 ℃, preferably 60 ℃.

In some preferred embodiments, the time for the heating polymerization is 20 to 40 hours, preferably 24 to 36 hours.

In some preferred embodiments, the heating polymerization further comprises purification, and the purification comprises vacuum drying and washing and drying.

In some preferred embodiments, the vacuum drying step is specifically: and (3) placing the polymerization product in a vacuum oven, and heating for 20-30 hours in vacuum at the temperature of 70-90 ℃.

In some preferred schemes, the step of washing and drying specifically comprises: and sequentially washing the vacuum-dried polymerization product by deionized water and dimethyl carbonate, and drying.

In another preferred embodiment of the present invention, the present invention provides a polymer electrolyte layer comprising the polymer electrolyte and a lithium salt.

In some preferred embodiments, the preparation of the polymer electrolyte layer comprises the steps of:

(1) mixing the polymer electrolyte, succinonitrile and dimethyl sulfoxide to form a polymer electrolyte solution;

(2) dissolving a lithium salt in the polymer electrolyte solution to form a viscous liquid;

(3) and coating the mucus on a current collector, and drying in vacuum to form the polymer electrolyte layer.

In some preferred embodiments, in the polymer electrolyte solution, the mass ratio of the polymer electrolyte, the succinonitrile and the dimethyl sulfoxide is l: m: n, wherein l is 45 to 50, m is 1 to 5, n is 45 to 50, and l + m + n is 100. For example, l: m: n: 48:2: 50.

In some preferred embodiments, the solid content in the polymer electrolyte solution is 45% to 55%, for example 50%.

In some preferred embodiments, in the slime, the lithium salt is selected from lithium fluorophosphate (LiPF)₆) Lithium tetrafluoroborate (LiBF)₄) Lithium perchlorate (LiClO)₄) Lithium hexafluoroarsenate (LiAsF)₆) Lithium trifluoromethanesulfonate (LiCF)₃SO₃) Lithium tetrafluoro oxalate phosphate (littop), lithium tris oxalate phosphate (LiTOP), bis (trifluoromethanesulfonic acid)Lithium imide (LiTFSI), lithium bis (perfluoroethylsulfonyl) imide (LiFSI), (lithium trifluoromethanesulfonyl) (n-perfluorobutylsulfonyl) imide (LiFNTFSI), and lithium fluorosulfonyl) (n-perfluorobutylsulfonyl) imide (LiFNFSI) lithium bis (LiBOB) oxalate.

In some preferred embodiments, the concentration of the lithium salt in the mucus is 1 to 2mol/L, such as 1.5 mol/L.

In some preferred embodiments, in step (3), the current collector is an aluminum foil, an aluminum plastic film CPP, or a release paper.

In order to remove the dimethyl sulfoxide sufficiently, in some preferred schemes, in the step (3), the vacuum drying time is 18-30 hours, such as 24 hours; the temperature of vacuum drying is 80-100 ℃.

In order to prevent the side reaction of the electrolyte material during vacuum drying, in some preferable schemes, during vacuum drying, the vacuum degree is firstly adjusted to be less than or equal to 0.1Pa, then the temperature is raised for vacuum drying, and then the vacuum is opened after the temperature is reduced.

In another preferred embodiment of the present invention, the present invention provides an all solid-state lithium ion battery including the polymer electrolyte layer.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the present invention is further described below with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out under conventional conditions or conditions recommended by the manufacturers. Unless otherwise indicated, percentages and parts are percentages and parts by weight. The test materials and reagents used in the following examples are commercially available without specific reference.

Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs, and it is to be noted that the terms used herein are merely for describing particular embodiments and are not intended to limit example embodiments of the present application.

In the following embodiments, the preparation processes of the polymer electrolyte, the polymer electrolyte layer and the all-solid-state lithium ion battery are completely performed in an argon environment glove box with water less than or equal to 0.1ppm, oxygen less than or equal to 0.1ppm and carbon dioxide less than or equal to 0.1ppm, before experimental operation, water removal work needs to be performed on materials such as propenyl-1, 3-sultone and vinyl sulfone, and a molecular sieve is used for removing water to ensure that the water content of the materials is less than or equal to 10 ppm. Defined below in terms of material mole fractions.

Example 1 preparation method of Polymer electrolyte Material (monomer is propenyl-1, 3-sultone)

Adding 94 mol percent of propenyl-1, 3-sultone, 3 mol percent of vinyl sulfone, 2.5 mol percent of PEGMEMA (polyethylene glycol monoethyl ether methacrylate) and 0.5 mol percent of azobisisobutyronitrile into a cyclohexane solvent for mixing to form a mixed solution with the solid content of about 20-50%. The resulting mixture was poured into a round bottom flask, a rotor was placed, and a reflux condenser tube was placed above the rotor. And (3) placing the round-bottom flask in an oil bath, heating the oil bath to 60 ℃, turning on a reflux condensing device and a magnetic stirring device, keeping heating and stirring for 24-36 hours, and stirring and heating to obtain a yellow or light yellow crystalline material. The material was removed from the round bottom flask and crushed to a powder to give a powdered polymer. The resulting powdered polymer was placed in a vacuum oven for vacuum drying to remove a portion of the unreacted propenyl-1, 3-sultone, vinylsulfone, PEGMEMA. The procedure for vacuum drying was as follows: vacuum heating at 80 deg.c for 24 hr to vacuum degree not higher than 0.1 Pa. Respectively washing the powdery polymer after vacuum drying in deionized water and dimethyl carbonate for multiple times, performing suction filtration and drying, and completely removing unreacted allyl-1, 3-sultone, vinyl sulfone and PEGMEMA; thus obtaining the purified polymer electrolyte material powder.

Example 2 preparation of Polymer electrolyte layer (monomer is propenyl-1, 3-sultone)

The preparation process is carried out under the dew point condition of less than or equal to-40 ℃.

The polymer electrolyte material powder prepared in example 1, succinonitrile and dimethyl sulfoxide were prepared into a solution with a solid content of 50% according to a mass ratio of 48:2: 50. LiTFSI was added to prepare a mixed solution having a lithium salt concentration of 1.5mol/L and a higher viscosity. And coating the prepared solution on the surface of the aluminum plastic film CPP, the aluminum foil or the release paper by using a scraper, wherein the distance between the scrapers is 50 mu m. Putting the coated solution into an oven for vacuum drying, and firstly adjusting the vacuum degree to be less than or equal to 0.1 Pa; then adjusting the temperature to 80-100 ℃, and vacuumizing for 24 hours to ensure that dimethyl sulfoxide is removed; the temperature reduction process is the same, the temperature is reduced to room temperature, and then the vacuum is opened, so that the side reaction of the electrolyte material at high temperature is prevented. And drying in vacuum to obtain the polymer electrolyte layer, wherein the thickness of the electrolyte layer is measured to be about 20-30 mu m.

Example 3 preparation of all solid-state lithium ion Battery

The preparation process of the battery is that the battery is prepared under the condition that the dew point condition is less than or equal to minus 40 ℃, and before the battery is prepared, the anode material and the cathode material are dried;

(1) preparation of positive pole piece

Firstly, dissolving the polymer electrolyte material obtained in the example 1 in dimethyl sulfoxide, adjusting the solid content to be 25%, then adding LITFSI, and adjusting the concentration of lithium salt to be about 0.75mol/L to obtain a polymer electrolyte Binder mixture;

mixing single crystal NCM811, a conductive agent Super-P and the polymer electrolyte Binder mixture according to the mass ratio of an active substance, a polymer electrolyte Binder mixture (polymer electrolyte and lithium salt) to the conductive agent of 75:22:3, adding dimethyl sulfoxide to adjust the solid content to 75%, uniformly mixing, stirring for 10 minutes at 2000rmp by using a Thinky defoaming stirrer, and then defoaming and stirring for 5 minutes at 500 rmp; coating the aluminum foil with a scraper coater to a thickness of about 100 mu m, drying at 80 ℃ after coating, putting the prepared positive plate into a vacuum oven to dry under the condition that the surface has no organic solvent, drying at 120 ℃ for 24 hours, and obtaining the positive plate after drying;

rolling the dried positive pole piece, wherein the rolling gap is 50 microns, the rolling temperature is 60 ℃, the speed is 10mm/s, and the rolled pole piece is 50-60 microns to obtain a finished positive pole piece;

(2) preparation of the electrolyte layer

Preparing an electrolyte layer according to the method of the embodiment 2 and compounding the prepared electrolyte layer with a positive pole piece;

(3) preparation of the Battery

And (3) punching the compounded positive electrode and electrolyte layer, wherein the diameter of the punched sheet is 12mm, and assembling the punched sheet and the lithium metal negative electrode into a button cell after punching is finished to obtain the all-solid-state lithium ion battery.

Example 4 preparation of all solid-state lithium ion Battery

Adding 94.5% of ethylene carbonate, 3% of ethylene glycol (glycol) diacrylate, 2.5% of PEGMEMA and 0.5% of azobisisobutyronitrile into a cyclohexane solvent, and mixing to form a mixed solution, wherein the solid content of the mixed solution is about 20-50%. Pouring the obtained mixed solution into a round-bottom flask, putting a rotor, and placing a reflux condenser pipe above the rotor; the round bottom flask was placed in an oil bath, the temperature of the oil bath was heated to 60 ℃ and the reflux condenser and magnetic stirrer were turned on. Keeping heating and stirring for 24-36 hours. Stirring and heating to obtain a light yellow crystalline material; the pale yellow crystalline material was taken out of the round-bottom flask and crushed into powder to give a powdery polymer. The resulting powdered polymer was placed in a vacuum oven for vacuum drying to remove a portion of the unreacted ethylene carbonate, ethylene glycol (diol) diacrylate, PEGMEMA, the procedure for vacuum drying was as follows: vacuum heating at 80 deg.c for 24 hr to vacuum degree not higher than 0.1 Pa. Cleaning the powder polymer after vacuum drying in cyclohexane and dimethyl carbonate for many times, filtering, drying, and completely removing unreacted ethylene carbonate, ethylene glycol (glycol) diacrylate, and PEGMEMA; obtaining the purified polymer electrolyte material powder.

The preparation process of the battery is that the battery is prepared under the condition that the dew point condition is less than or equal to minus 40 ℃, and before the battery is prepared, the anode material and the cathode material are dried;

(1) preparation of positive pole piece

Firstly, dissolving the polymer electrolyte material in dimethyl sulfoxide, adjusting the solid content to be 25%, then adding LITFSI, and adjusting the concentration of lithium salt to be about 0.75mol/L to obtain a polymer electrolyte Binder mixture;

mixing single crystal NCM811, a conductive agent Super-P and the polymer electrolyte Binder mixture according to the mass ratio of an active substance, the polymer electrolyte Binder mixture (polymer electrolyte and lithium salt) to the conductive agent of 75:22:3, adding dimethyl sulfoxide to adjust the solid content to 75%, uniformly mixing, stirring for 10 minutes at 2000rmp by using a Thinky defoaming stirrer, and then defoaming and stirring for 5 minutes at 500 rmp; coating the aluminum foil with a scraper coater to a thickness of about 100 mu m, drying at 80 ℃ after coating, putting the prepared positive plate into a vacuum oven to dry under the condition that the surface has no organic solvent, drying at 120 ℃ for 24 hours, and obtaining the positive plate after drying;

rolling the dried positive pole piece, wherein the rolling gap is 50 microns, the rolling temperature is 60 ℃, the speed is 10mm/s, and the rolled pole piece is 50-60 microns to obtain a finished positive pole piece;

(2) preparation of the electrolyte layer

An electrolyte layer was prepared according to the method of example 2; after the preparation is finished, taking down the electrolyte layer, and compounding the electrolyte layer with the positive pole piece;

(3) preparation of the Battery

And (3) punching the compounded positive electrode and electrolyte layer, wherein the diameter of the punched sheet is 12mm, and assembling the punched sheet and the lithium metal negative electrode into a button cell after punching is finished to obtain the all-solid-state lithium ion battery.

Example 5 preparation of Polymer electrolyte layer

In this example, the method for producing a polymer electrolyte material powder was substantially the same as in example 1, and the method for producing a polymer electrolyte layer was substantially the same as in example 2, except that the following monomer was used:

monomer structure:

example 6 preparation of Polymer electrolyte layer

In this example, the method for producing a polymer electrolyte material powder was substantially the same as in example 1, and the method for producing a polymer electrolyte layer was substantially the same as in example 2, except that the following monomer was used:

monomer structure:

example 7 preparation of Polymer electrolyte layer

In this example, the method for producing a polymer electrolyte material powder was substantially the same as in example 1, and the method for producing a polymer electrolyte layer was substantially the same as in example 2, except that the following monomer was used:

monomer structure:

example 8 preparation of Polymer electrolyte layer

In this example, the method for producing the polymer electrolyte material powder was substantially the same as in example 1, and the method for producing the polymer electrolyte layer was substantially the same as in example 2, except that triethylene glycol diacrylate was used as the crosslinking agent.

Example 9 preparation of Polymer electrolyte layer

In this example, the method for producing a polymer electrolyte material powder was substantially the same as in example 1, and the method for producing a polymer electrolyte layer was substantially the same as in example 2, except that the crosslinking agent used was pentaerythritol tetraacrylate.

Comparative example 1 preparation of polycarbonate electrolyte layer

The preparation process is substantially the same as the preparation method of the polymer electrolyte in the embodiment 2, and the difference is that the used electrolyte material powder is polycarbonate electrolyte material powder. The specific method comprises the following steps:

the preparation method of the polycarbonate electrolyte material powder comprises the following steps: adding 94.5% of ethylene carbonate, 3% of ethylene glycol (glycol) diacrylate, 2.5% of PEGMEMA and 0.5% of azobisisobutyronitrile into a cyclohexane solvent, and mixing to form a mixed solution with the solid content of about 20-50%. Pouring the obtained mixed solution into a round-bottom flask, putting a rotor, and placing a reflux condenser pipe above the rotor; placing the round-bottom flask in an oil bath, heating the oil bath to 60 ℃, and turning on a reflux condensing device; the magnetic stirring device was turned on. Keeping heating and stirring for 24-36 hours. Stirring and heating to obtain a light yellow crystalline material; the pale yellow crystalline material was taken out of the round-bottom flask and crushed into powder to give a powdery polymer. The resulting powdered polymer was placed in a vacuum oven for vacuum drying to remove a portion of the unreacted ethylene carbonate, ethylene glycol (diol) diacrylate, PEGMEMA, the procedure for vacuum drying was as follows: and (2) heating the mixture in vacuum at the temperature of 80 ℃ for 24 hours with the vacuum degree of less than or equal to 0.1Pa, respectively washing the powdery polymer after vacuum drying in cyclohexane and dimethyl carbonate for multiple times, performing suction filtration and drying, and completely removing ethylene carbonate, ethylene glycol (glycol) diacrylate and PEGMEMA which are not completely reacted to obtain purified polycarbonate electrolyte material powder.

The preparation method of the polycarbonate electrolyte layer comprises the following steps: preparing polycarbonate electrolyte material powder, succinonitrile and dimethyl sulfoxide into a solution according to the mass ratio of 48:2:50, wherein the solid content is 50%. LiTFSI was added to prepare a mixed solution having a lithium salt concentration of 1.5mol/L and a higher viscosity. And coating the prepared solution on the surface of the aluminum plastic film CPP or the aluminum foil by using a scraper, wherein the distance between the scrapers is 50 mu m. Putting the coated solution into an oven for vacuum drying, and firstly adjusting the vacuum degree to be less than or equal to 0.1 Pa; then adjusting the temperature to 80-100 ℃, and vacuumizing for 24 hours to ensure that dimethyl sulfoxide is removed; the temperature reduction process is the same, the temperature is reduced to room temperature, and then the vacuum is opened, so that the side reaction of the electrolyte material at high temperature is prevented. And drying in vacuum to obtain the polycarbonate electrolyte layer.

Comparative example 2 preparation of all solid-state lithium ion Battery

The method of manufacturing the all solid-state lithium ion battery in comparative example 2 was substantially the same as in example 3, except that the polymer electrolyte layer used was the polycarbonate electrolyte layer prepared in comparative example 1.

Test example 1 conductivity test

The polymer electrolyte layers prepared in example 2 and comparative example 1 were punched in a glove box to assemble a structure of an aluminum foil | electrolyte layer | aluminum foil, and a conductivity test was performed using a die battery. The specific test conditions were: diameter 10mm, measured using a Bio-logic MTZ-35 impedance analyzer, frequency 35MHz-0.1 Hz. The test results are shown in Table 1.

Test example 2 tensile Strength test

The polymer electrolyte layers prepared in example 2 and comparative example 1 were subjected to a tensile strength test using a separator test tensile strength tester. The specific test conditions were: the all-solid electrolyte or solid electrolyte provided above was tested using a cell separator tensile strength tester (Labthink blue model XLW tensile tester). The test results are shown in Table 1.

Test example 3 direct current polarized electron conductivity test

The polymer electrolyte layers prepared in example 2 and comparative example 1 were subjected to a dc polarized electron conductivity test. The specific test conditions were: in a glove box, under the condition of 25 ℃, a die battery is used, blocking electrodes (electron conduction and ion blocking) are used at two ends, a corresponding polymer electrolyte layer is clamped in the middle, a constant voltage of 0.5V is applied for 3000s of direct current polarization, the current after the direct current 3000s is recorded, the electronic resistance is equal to the constant voltage/the direct current, and then the electronic conductivity is calculated through a conductivity test formula. The test results are shown in Table 1.

Test example 4 electrolyte layer electrochemical Window test

The polymer electrolyte layers prepared in example 2 and comparative example 1 were subjected to electrolyte layer electrochemical window test. The specific test conditions were: assembling a Li polymer electrolyte layer SUS button cell with a lithium ion blocking electrode stainless steel sheet on one side in a glove box at 25 ℃; one side is a lithium-copper composite belt of the lithium ion reversible electrode; in the middle is a corresponding polymer solid electrolyte layer. The sweep voltage of cyclic voltammetry was first swept from the open circuit voltage to-0.5V and then from-0.5V to 10V, and the sweep rate was cycled to 0.5mV/s, confirming the initial oxidation current position of the cell. The test results are shown in Table 1.

TABLE 1

Test example 5, Battery Performance test

Button cells were prepared as described in example 4 and tested for cell performance as follows.

(1) Initial coulombic efficiency based normal temperature capacity test

The first coulombic efficiency and the room temperature capacity were measured at 25 ℃ in the steps shown in table 2 below. Wherein the first coulombic efficiency is 0.1C discharge capacity/0.1C charge capacity 100%; the capacity at room temperature was 1/3C discharge capacity. The test results are shown in Table 5.

TABLE 2

(2) High temperature capacity test the high temperature capacity was tested at 45 ℃ in the steps shown in table 3 below.

TABLE 3

Number of steps	Working steps	Mode of operation	Ambient temperature	Interval of sampling point
					1	Standing still	Rest 30min；	25℃	30s
2	Constant current and constant voltage charging	0.1C CC to 4.2V，CV to 0.05C；	25℃	5s
					3	Standing still	Rest 5min；	25℃	30s
4	Constant current discharge	0.1C DC to 2.5V；	25℃	5s
					5	Standing still	Rest 5min；	25℃	30s
6	Constant current and constant voltage charging	1/3C CC to 4.2V，CV to 0.05C；	25℃	5s
					7	Standing still	Rest 60min；	45℃	30s
8	Constant current discharge	1/3C DC to 2.5V；	45℃	5s
					9	Standing still	Rest 5min；	45℃	30s

(3) Low temperature capacity test

The low temperature capacity was tested at-20 ℃ in the steps shown in Table 4 below.

TABLE 4

The results of the above battery performance tests are shown in table 5.

TABLE 5

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.