CN118511327A - Amide compound and preparation method thereof, pole piece, secondary battery and power utilization device - Google Patents

Abstract

Relates to an amide compound and a preparation method thereof, a pole piece, a secondary battery and an electric device. The amide compound can be used as an impregnating compound to be added into the polar plate slurry, so that the dynamic problem of electrolyte impregnation is effectively improved, the wettability of the electrolyte to the polar plate is obviously improved, the impedance of a battery is reduced, the electrochemical performance is improved, the impregnation time is not required to be increased, or the polar plate is subjected to high-temperature standing, the production cost is reduced, and the production efficiency is improved.

Description

Amide compound and preparation method thereof, pole piece, secondary battery and power utilization device Technical Field

The application relates to the technical field of lithium batteries, in particular to an amide compound and a preparation method thereof, a pole piece, a secondary battery and an electric device.

Background

With the wider application range of lithium ion batteries, the lithium ion batteries with higher energy density are urgently needed to meet the increasing market demands in electric automobiles, portable electronic devices and power grid energy storage. In addition to the development of new cell chemistries, materials or systems in recent years, thick electrode structural designs are more versatile and easy to implement because the electrochemical basis of existing cells need not be changed, and the cell energy density is increased by increasing the proportion of electrochemically active material in the cell.

However, the thick electrode structure can seriously affect the diffusion speed of lithium ions, so that the rate performance of the battery is reduced, the electrolyte seepage capability of the pole piece is deteriorated due to higher compaction density, the electrolyte is unevenly distributed in the electrode, the electrolyte is difficult to infiltrate, the impedance is increased, the lithium ions are not transmitted easily, and the electrochemical performance is reduced. In order not to affect the infiltration of the pole piece, the infiltration time is generally increased or the high-temperature standing is performed, but the working procedure time is increased, and the production efficiency is reduced.

Disclosure of Invention

According to various embodiments of the present application, a first aspect of the present application provides an amide compound having the structural features shown below:

Wherein R ₁ is C1-C15 alkyl substituted or unsubstituted with one or more R ₀;

R ₂ is C1-C15 alkyl substituted or unsubstituted with one or more R ₀;

R ₀ is independently selected from one of the following substituents for each occurrence: H. a heterocyclic group of C3-C8, a sulfonate group of C1-C8, an ester group of C1-C8, a phosphate group of C1-C8, an alkoxy group of C1-C8, an alkylthio group of C1-C8, an alkenyl group of C2-C8 and an alkynyl group of C2-C8.

The second aspect of the present application also provides a method for preparing an amide compound, comprising the steps of:

Carrying out amidation reaction on the compound 1 and the compound 2 to prepare an intermediate 1;

Carrying out amidation reaction on the intermediate 1 and the compound 3 to prepare the amide compound;

Or, carrying out amidation reaction on the compound 1 and the compound 3 to prepare an intermediate 2;

Carrying out amidation reaction on the intermediate 2 and the compound 2 to prepare the amide compound;

wherein the structures of compound 1, compound 2, compound 3, intermediate 1 and intermediate 2 are as follows:

the third aspect of the present application also provides an impregnating compound comprising one or more of the amide compounds of the first aspect.

The fourth aspect of the application also provides a pole piece slurry, which comprises an electrode active material, the impregnating compound in the third aspect and a solvent.

The fifth aspect of the present application also provides a method for preparing a pole piece, comprising the steps of:

And preparing an electrode layer on the surface of the current collector by adopting the pole piece slurry in the fourth aspect.

The sixth aspect of the application also provides a pole piece, which comprises a current collector and an electrode layer arranged on the surface of the current collector, wherein the composition of the electrode layer comprises an electrode active material and the impregnating compound in the third aspect.

A seventh aspect of the present application also provides a secondary battery comprising the electrode sheet of the sixth aspect.

An eighth aspect of the application also provides an electric device comprising the secondary battery selected from the seventh aspect of the application.

Drawings

Fig. 1 is a schematic view of a secondary battery according to an embodiment of the present application;

fig. 2 is an exploded view of the secondary battery according to an embodiment of the present application shown in fig. 1;

Fig. 3 is a schematic view of a battery module according to an embodiment of the present application;

fig. 4 is a schematic view of a battery pack according to an embodiment of the present application;

fig. 5 is an exploded view of the battery pack of the embodiment of the present application shown in fig. 4;

fig. 6 is a schematic view of an electric device in which a secondary battery according to an embodiment of the present application is used as a power source;

Reference numerals illustrate:

1. A battery pack; 2. an upper case; 3. a lower box body; 4. a battery module; 5. a secondary battery; 51. a housing; 52. an electrode assembly; 53. a cover plate; 6. an electric device;

FIG. 7 is an infrared spectrum of the treating compound 1 used in example 1 of the present application.

Detailed Description

Hereinafter, embodiments of the amide-based compound, the method for producing the same, the electrode sheet, the secondary battery, and the electric device of the present application are specifically disclosed with reference to the accompanying drawings as appropriate. However, unnecessary detailed description may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of the actual same structure may be omitted. This is to avoid that the following description becomes unnecessarily lengthy, facilitating the understanding of those skilled in the art. Furthermore, the drawings and the following description are provided for a full understanding of the present application by those skilled in the art, and are not intended to limit the subject matter recited in the claims.

The "range" disclosed herein is defined in terms of lower and upper limits, with the given range being defined by the selection of a lower and an upper limit, the selected lower and upper limits defining the boundaries of the particular range. Ranges that are defined in this way can be inclusive or exclusive of the endpoints, and any combination can be made, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3,4 and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise indicated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed throughout, and "0-5" is simply a shorthand representation of a combination of these values. When a certain parameter is expressed as an integer of 2 or more, it is disclosed that the parameter is, for example, an integer of 2,3,4,5,6,7, 8, 9, 10,11, 12 or the like.

All embodiments of the application and alternative embodiments may be combined with each other to form new solutions, unless otherwise specified.

All technical features and optional technical features of the application may be combined with each other to form new technical solutions, unless specified otherwise.

All the steps of the present application may be performed sequentially or randomly, preferably sequentially, unless otherwise specified. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, or may comprise steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), may include steps (a), (c) and (b), may include steps (c), (a) and (b), and the like.

The terms "comprising" and "including" as used herein mean open ended or closed ended, unless otherwise noted. For example, the terms "comprising" and "comprises" may mean that other components not listed may be included or included, or that only listed components may be included or included.

The term "or" is inclusive in this application, unless otherwise specified. For example, the phrase "a or B" means "a, B, or both a and B. More specifically, either of the following conditions satisfies the condition "a or B": a is true (or present) and B is false (or absent); a is false (or absent) and B is true (or present); or both A and B are true (or present).

Unless otherwise specified, in the present application, the term "alkyl" refers to a monovalent residue of a saturated hydrocarbon containing a primary (positive) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof, losing one hydrogen atom. The phrase containing the term, for example, "C1-C15 alkyl" refers to an alkyl group containing 1 to 15 carbon atoms, and each occurrence may be, independently of the other, C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl, C10 alkyl, C11 alkyl, C12 alkyl, C13 alkyl, C14 alkyl, C15 alkyl. Suitable examples include, but are not limited to: methyl (Me, -CH ₃), ethyl (Et, -CH ₂CH ₃), 1-propyl (n-Pr, n-propyl, -CH ₂CH ₂CH ₃), 2-propyl (i-Pr, i-propyl), -CH (CH ₃) ₂), 1-butyl (n-Bu, n-butyl, -CH ₂CH ₂CH ₂CH ₃), 2-methyl-1-propyl (i-Bu, i-butyl, -CH ₂CH(CH ₃) ₂), 2-butyl (s-Bu, s-butyl), -CH (CH ₃)CH ₂CH ₃), 2-methyl-2-propyl (t-Bu, t-butyl, -C (CH ₃) ₃), 1-pentyl (n-pentyl, -CH ₂CH ₂CH ₂CH ₂CH ₃), 2-pentyl (-CH (CH 3) CH2CH2CH 3), 3-pentyl (-CH (CH ₂CH ₃) ₂), 2-methyl-2-butyl (-C (CH ₃) ₂CH ₂CH ₃), 3-methyl-2-butyl (-CH (CH ₃)CH(CH ₃) ₂), 3-methyl-1-butyl (-CH ₂CH ₂CH(CH ₃) ₂), 2-methyl-1-butyl (-CH ₂CH(CH ₃)CH ₂CH ₃), 1-hexyl (-CH ₂CH ₂CH ₂CH ₂CH ₂CH ₃), 2-hexyl (-CH (CH ₃)CH ₂CH ₂CH ₂CH ₃), 3-hexyl (-CH (CH ₂CH ₃)(CH ₂CH ₂CH ₃))), 2-methyl-2-pentyl (-C (CH ₃) ₂CH ₂CH ₂CH ₃), 3-methyl-2-pentyl (-CH (CH ₃)CH(CH ₃)CH ₂CH ₃), 4-methyl-2-pentyl (-CH (CH ₃)CH ₂CH(CH ₃) ₂), 3-methyl-3-pentyl (-C (CH ₃)(CH ₂CH ₃) ₂)), a catalyst for the preparation of a pharmaceutical composition, 2-methyl-3-pentyl (-CH (CH ₂CH ₃)CH(CH ₃) ₂), 2, 3-dimethyl-2-butyl (-C (CH ₃) ₂CH(CH ₃) ₂), 3-dimethyl-2-butyl (-CH (CH ₃)C(CH ₃) ₃) and octyl (- (CH ₂) ₇CH ₃)).

In the present application, unless otherwise specified, the term "alkoxy" refers to a group having the structure-O-alkyl, i.e., an alkyl group as defined above is attached to a parent nucleus structure adjacent group via an oxygen atom. The phrase containing the term, for example, "C1-C8 alkoxy" means that the alkyl moiety contains from 1 to 8 carbon atoms, and each occurrence may be, independently of the other, C1 alkoxy, C4 alkoxy, C5 alkoxy, C6 alkoxy, C7 alkoxy, or C8 alkoxy. Suitable examples include, but are not limited to: methoxy (-O-CH ₃ or-OMe), ethoxy (-O-CH ₂CH ₃ or-OEt), and t-butoxy (-O-C (CH ₃) ₃ or-OtBu).

In the present application, unless otherwise specified, the term "alkylthio" refers to a group having the structure-S-alkyl, i.e., an alkyl group as defined above is attached to the parent nucleus structure adjacent group via a sulfur atom. The phrase containing the term, for example, "C1-C8 alkylthio" means that the alkyl moiety contains from 1 to 8 carbon atoms, and each occurrence can be, independently of the other, C1 alkylthio, C4 alkylthio, C5 alkylthio, C6 alkylthio, C7 thio, or C8 alkylthio. Suitable examples include, but are not limited to: methylthio (-S-CH ₃ or-SMe), ethylthio (-S-CH ₂CH ₃ or-SEt), and tert-butylthio (-S-C (CH ₃) ₃ or-StBu).

Unless otherwise specified, in the present application, the term "alkenyl" refers to a monovalent residue formed by losing one hydrogen atom from a hydrocarbon containing a normal carbon atom, a secondary carbon atom, a tertiary carbon atom or a cyclic carbon atom having at least one unsaturated site, i.e., a carbon-carbon sp2 double bond. The phrase containing the term, for example, "C2-C8 alkenyl" refers to alkenyl groups containing 2 to 8 carbon atoms, which at each occurrence may be, independently of one another, C2 alkenyl, C3 alkenyl, C4 alkenyl, C5 alkenyl, C6 alkenyl, C7 alkenyl, or C8 alkenyl. Suitable examples include, but are not limited to: vinyl (-ch=ch ₂), allyl (-CH ₂CH＝CH ₂), cyclopentenyl (-C ₅H ₇), and 5-hexenyl (-CH ₂CH ₂CH ₂CH ₂CH＝CH ₂).

Unless otherwise specified, in the present application, the term "alkynyl" refers to a monovalent residue formed by losing one hydrogen atom from a hydrocarbon containing a normal carbon atom, a secondary carbon atom, a tertiary carbon atom or a cyclic carbon atom having at least one unsaturated site, i.e., a carbon-carbon sp triple bond. The phrase containing the term, for example, "C2-C8 alkynyl" refers to alkynyl groups containing 2-8 carbon atoms, which at each occurrence may be, independently of one another, C2 alkynyl, C3 alkynyl, C4 alkynyl, C5 alkynyl, C6 alkynyl, C7 alkynyl or C8 alkynyl. Suitable examples include, but are not limited to: ethynyl (-C≡CH) and propargyl (-CH ₂ C≡CH).

Unless otherwise specified, in the present application, the term "heterocyclic group" means that at least one carbon atom is replaced with a non-carbon atom on the basis of an aryl group, and the non-carbon atom may be an N atom, an O atom, an S atom, or the like. For example, "C3-C8 heteroaryl" refers to heteroaryl groups containing 3 to 8 carbon atoms, which at each occurrence may be, independently of one another, C3 heteroaryl, C4 heteroaryl, C5 heteroaryl, C6 heteroaryl, C7 heteroaryl or C8 heteroaryl. Suitable examples include, but are not limited to: furan, benzofuran, thiophene, benzothiophene, pyrrole, pyrazole, triazole, imidazole, oxazole, oxadiazole, thiazole, tetrazole, indole, carbazole, pyrroloimidazole, pyrrolopyrrole, thienopyrrole, thienothiophene, furopyrrole, furofuran, thienofuran, benzisoxazole, benzisothiazole, benzimidazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, naphthyridine, quinoxaline, phenanthridine, primary pyridine, quinazoline, and quinazolinone.

In the present application, the term "sulfonate group" has the structure ofWherein R represents an alkyl group, for example "C1-C8 sulfonate group" represents a C1-C8 alkyl group in the above structure.

In the present application, the term "ester group" means having the structure ofWherein R represents an alkyl group, for example "C1-C8 sulfonate group" represents a C1-C8 alkyl group in the above structure.

In the present application, the term "phosphate group" means having the structure ofWherein R represents an alkyl group, for example "a C1-C8 phosphate group" represents a C1-C8 alkyl group in the above-mentioned structure.

The application provides an amide compound, which has the following structural characteristics:

Wherein R ₁ is C1-C15 alkyl substituted or unsubstituted with one or more R ₀;

R ₂ is C1-C15 alkyl substituted or unsubstituted with one or more R ₀;

R ₀ is independently selected from one of the following substituents for each occurrence: H. a heterocyclic group of C3-C8, a sulfonate group of C1-C8, an ester group of C1-C8, a phosphate group of C1-C8, an alkoxy group of C1-C8, an alkylthio group of C1-C8, an alkenyl group of C2-C8 and an alkynyl group of C2-C8.

The amide compound can be used as an impregnating compound to be added into pole piece slurry, so that the dynamic problem of electrolyte impregnation is effectively improved, the wettability of the electrolyte to the pole piece is obviously improved, the impedance of a battery is reduced, the electrochemical performance is improved, the impregnation time is not required to be increased, or the high-temperature standing is not required, the production and manufacturing cost can be reduced, and the production efficiency is improved.

Meanwhile, under the condition of small addition amount of the amide compound, the wettability of the electrolyte to the pole piece can be obviously improved. In particular, the amide compound can effectively improve the wettability of the electrolyte to the thick electrode.

Without limitation, the possible reasons for the improvement of wettability of the pole piece by the amide compounds are as follows:

The molecules form a one-dimensional network structure through pi-pi conjugation of benzene rings, and a three-dimensional network is formed by combining a specific R ₁、R ₂ structure, so that the electrolyte molecules can be bound, and the electrolyte can be quickly soaked by matching with a specific amide group, and meanwhile, the migration rate of the electrolyte is increased. Therefore, the wettability and the liquid retention capacity of the pole piece are improved, the contact of the electrolyte and the active particles is increased, the mass transfer probability is increased, the migration number of lithium ions is increased, the occurrence probability of lithium dendrites is reduced, the short circuit risk of the battery core is reduced, the dynamic performance of the electrode is further improved, the interface dynamics and the cycle performance of the secondary battery are improved, the quick charging is realized, the lithium separation risk is reduced, the safety of the battery core is improved, meanwhile, the production cost is reduced, the infiltration time is shortened, and the productivity is improved.

Further, the pole piece is generally prepared by conventional wet pulping, which is prepared by uniformly mixing an active substance, a binder, a conductive agent, a dispersing agent and a solvent to prepare slurry, then coating the slurry on a current collector, and rolling and die-cutting the slurry. The method has a certain limit on the solid content of the slurry, and coating cannot be finished due to the fact that the solid content is too high. Compared with the traditional wet pulping, the dry electrode technology does not use any solvent in the preparation process of the pole piece, the pole piece can be prepared only by mixing dry powder, the preparation process is environment-friendly and pollution-free, and the production cost of a battery can be reduced to a great extent, but the dry electrode is easy to have the condition of uneven powder distribution in the pole piece in the preparation process, and has no solvent membrane, particles slide difficultly in the rolling process, the pole piece is difficult to compact, thus the pole piece cannot be compacted, a high-energy density battery cannot be ensured, and the active particles are easy to crush the fibrous binder (such as PTFE) in the pole piece rolling process, so that the utilization efficiency of the binder is reduced, excessive binder needs to be added, the content of the binder reaches 5% -10%, the occupation ratio of the active material is reduced, and the energy density of the battery is reduced. The quasi-dry electrode technology combines the advantages of the traditional wet pulping and dry electrode technology, and is characterized in that a small amount of solvent is added in the material preparation process, so that the extruded membrane can greatly promote particle sliding in the rolling and thinning process, the solvent has the function similar to that of a lubricant, the membrane is not easy to roll excessively, the membrane is softer, the processability is better, the pole piece is easier to compact, a high-energy-density battery is realized, and the quasi-dry electrode technology is particularly suitable for preparing a thick electrode structure. However, conventional sizing agents are not suitable for quasi-dry electrode technology because: in the quasi-dry electrode system, the conventional impregnating compound is insufficient to provide sufficient electrolyte impregnating capability, and cannot form a three-dimensional network structure to sufficiently bind electrolyte molecules, and if the addition amount is increased, the energy density of the battery cell is reduced. The amide compound provided by the application can effectively solve the problem, can be used as an impregnating compound to be applied to a quasi-dry pole piece system so as to prepare a thick electrode structure and improve the energy density of a battery cell.

In some embodiments, R ₂ is unsubstituted C1 to C15 alkyl. Further, R ₂ is unsubstituted C1-C8 alkyl. Further, R ₂ is unsubstituted C1-C5 alkyl.

In other embodiments, R ₂ is C1-C15 alkyl substituted with one or more R ₀.

In some embodiments, R ₁ is C1-C10 alkyl substituted or unsubstituted with one or more R ₀. Further, R ₁ is C1-C6 alkyl substituted or unsubstituted with one or more R ₀.

In some embodiments, each occurrence of R ₀ is independently selected from one of the substituents of the following groups: sulfonate group of C1-C5, ester group of C1-C5, phosphate group of C1-C5, alkoxy group of C1-C5, alkylthio group of C1-C5, alkenyl group of C2-C5 and alkynyl group of C2-C5.

In some embodiments, each occurrence of R ₀ is independently selected from one of the substituents of the following groups: sulfonate group of C1-C4, ester group of C1-C3, phosphate group of C1-C4, alkoxy group of C1-C3, alkylthio group of C1-C3, alkenyl group of C2-C3 and alkynyl group of C2-C3.

In some embodiments, each occurrence of R ₀ is independently selected from one of the substituents of the following groups:

in some embodiments, the amide is selected from one of the following:

the application also provides a preparation method of the amide compound, which comprises the following steps:

Carrying out amidation reaction on the compound 1 and the compound 2 to prepare an intermediate 1;

Carrying out amidation reaction on the intermediate 1 and the compound 3 to prepare the amide compound;

Or, carrying out amidation reaction on the compound 1 and the compound 3 to prepare an intermediate 2;

Carrying out amidation reaction on the intermediate 2 and the compound 2 to prepare the amide compound;

wherein the structures of compound 1, compound 2, compound 3, intermediate 1 and intermediate 2 are as follows:

The application also provides an impregnating compound, the composition of which comprises one or more of the amide compounds.

The application also provides a pole piece slurry, which comprises an electrode active material, the impregnating compound and a solvent.

In some embodiments, the mass percentage of the sizing agent in the pole piece slurry is 0.1-0.5%. The impregnating compound can achieve obvious improvement of wettability with smaller mass percentage. Meanwhile, without intending to be limited by any theory or explanation, the inventor finds that the mass ratio of the impregnating compound in the pole piece slurry is in the above proper range, and can effectively increase the electrolyte impregnation rate and simultaneously enable the pole piece to have higher energy density, cycle performance and multiplying power performance. If the addition amount is too large, the energy density is not improved, and if the addition amount is too small, the infiltration rate of the electrolyte is reduced. Specifically, the mass percent of the sizing agent includes, but is not limited to: 0.1%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.5%. Further, the mass percentage of the impregnating compound is 0.2% -0.4%.

In some embodiments, the solvent comprises one or more of water, an alcoholic solvent, and an ester solvent; optionally, the alcoholic solvent comprises one or more of 1, 3-propanediol, 1, 2-propanediol, 1, 4-butanediol, and 1, 3-butanediol; optionally, the ester solvent includes one or more of triethyl phosphate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and propylene carbonate.

Further, in wet pulping, the solvent comprises water.

Further, in pulping of quasi-dry electrode technology, the solvent includes one or more of water, an alcoholic solvent, and an ester solvent; optionally, the alcoholic solvent comprises one or more of 1, 3-propanediol, 1, 2-propanediol, 1, 4-butanediol, and 1, 3-butanediol; optionally, the ester solvent includes one or more of triethyl phosphate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and propylene carbonate. Still further, in pulping of quasi-dry electrode technology, the solvent comprises water.

In some embodiments, the pole piece slurry has a solids content of < 65%. This was used as a slurry prepared by wet pulping.

In some embodiments, the solid content of the pole piece slurry is 65% to 85%. Thus serving as a slurry for quasi-dry electrode technology.

In some embodiments, the pole piece slurry further comprises a binder. Optionally, the binder comprises one or more of styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid and carboxymethyl chitosan, or the binder comprises one or more of Polytetrafluoroethylene (PTFE), acrylonitrile, copolymer of acrylic acid and acrylamide, or copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, copolymer of tetrafluoroethylene and hexafluoropropylene, and copolymer of poly (chlorotrifluoroethylene), and copolymer of ethylene and chlorotrifluoroethylene. Further, the binder comprises polytetrafluoroethylene.

Further, in wet pulping, the binder comprises one or more of styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid and carboxymethyl chitosan. Further, the weight average molecular weight of the binder is more than 100000, and the solid content is 20% -60%.

In some embodiments, the mass percent of the binder in the pole piece slurry is 0.05% -3%. Specifically, in the pole piece slurry, the mass percentage of the binder includes, but is not limited to: 0.05%, 0.1%, 0.5%, 1%, 1.2%, 1.5%, 1.7%, 2%, 3%.

Further, in pulping of quasi-dry electrode technology, the binder includes a first binder and a second binder.

Specifically, the first binder includes Polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, a copolymer of tetrafluoroethylene and hexafluoropropylene, and polytrifluoroethylene, a copolymer of ethylene and chlorotrifluoroethylene, preferably polytetrafluoroethylene. Further, the first binder has a weight average molecular weight of greater than ten million and an SSG (relative standard density) of 2.13 to 2.19.

In some embodiments, the mass percent of the first binder in the pole piece slurry is 0.05% to 0.5%. Specifically, in the pole piece slurry, the mass percentage of the first binder includes, but is not limited to: 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%.

Specifically, the second binder includes a copolymer of one or more of acrylonitrile, acrylic acid, and acrylamide. Further, the second binder comprises an acrylic acid/acrylonitrile/acrylamide copolymer, without limitation, and the mole percentages of the three monomers of acrylic acid, acrylonitrile and acrylamide are (30% -60%): (20% -40%): (20% -30%). Further alternatively, the second binder has a weight average molecular weight of greater than 300000 and a solids content of 4% to 7%.

In some embodiments, the mass percent of the second binder in the pole piece slurry is 0.5% -4%. Specifically, in the pole piece slurry, the mass percentage of the second binder includes, but is not limited to: 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%.

In some embodiments, in wet pulping, the pole piece slurry comprises the following components in mass percent: 89.5 to 98.6 percent of electrode active material, 0.3 to 4 percent of conductive agent, 0.5 to 3 percent of binder, 0.5 to 3 percent of thickener and 0.1 to 0.5 percent of impregnating compound. The solvent is used in an amount such that the solid content of the pole piece slurry is less than 65%.

In some embodiments, in pulping of quasi-dry electrode technology, the pole piece slurry comprises the following components in mass percent: 91 to 99.05 percent of electrode active material, 0.3 to 4 percent of conductive agent, 0.05 to 0.5 percent of first binder, 0.5 to 4 percent of second binder and 0.1 to 0.5 percent of impregnating compound. The dosage of the solvent is such that the solid content of the pole piece slurry is 65-85%. By reasonably controlling the percentage content of each component, the components are easy to prepare into bulk materials, the membrane is not easy to be excessively rolled, the membrane is softer, the processing performance is better, the pole piece is easier to be compacted, the thick pole piece is easier to prepare, and the high-energy-density battery is realized. Meanwhile, the amount of the solvent added in the formula system is far lower than that of a wet coating process, so that the drying energy consumption is greatly reduced, the environmental pollution is reduced, and the prepared membrane has a surface non-stick function, so that a winding type oven can be adopted in the oven, the length of the oven can be greatly shortened, the occupied area of equipment is reduced, and the technical cost can be reduced.

The application also provides a preparation method of the pole piece slurry, which comprises the following steps:

The electrode active material, the impregnating agent as described above, and the solvent are mixed.

It can be appreciated that the solution of the pole piece slurry is the same as above, and will not be described herein.

In some embodiments, the pole piece slurry is prepared by a quasi-dry method.

In some embodiments, the preparation method of the pole piece slurry comprises the following steps:

Mixing the electrode active material and a first binder to prepare a first premix;

mixing the impregnating compound, the second binder and the solvent to prepare a second premix;

And mixing the first premix and the second premix to prepare the pole piece slurry.

The equipment for mixing the materials may be, without limitation, internal mixers, kneaders, twin screw equipment, etc.

The application also provides a preparation method of the pole piece, which comprises the following steps:

Electrode layers were prepared using the electrode sheet slurry described above on the surface of the current collector.

In some embodiments, the pole piece slurry is wet pulping. Further, the method for preparing the electrode layer by using the electrode plate slurry on the surface of the current collector can be coating and the like.

In some embodiments, the pole piece slurry is prepared by a pulping process of quasi-dry electrode technology. It will be appreciated that the pole piece slurry is typically a solid with a degree of softness and deformability, similar to a dough. Further, the step of preparing an electrode layer on the surface of the current collector by using the pole piece slurry comprises the following steps:

Shaping the pole piece slurry to prepare a membrane;

And compounding the membrane with the current collector.

The apparatus for producing the film sheet may be, without limitation, a screw extruder, a hydraulic extruder, a ram extruder, or the like. Wherein the flighted elements of the screw elements may be combined by one or more of flights, engagement blocks, tooth plates, and sufficient balance of shear mixing and conveying capacity. The thickness of the film sheet is controlled by the extrusion die.

In some embodiments, the membrane has a thickness of 3mm to 10mm.

The membrane may be directly combined with the current collector, or may be further combined with the current collector after being thinned and transferred by one or more stages of rolling.

In some embodiments, the composition further comprises a drying step after compounding. The drying may be, without limitation, a winding type stereo oven drying.

In some embodiments, the method for preparing the pole piece can realize continuous production.

The application also provides a pole piece, which comprises a current collector and an electrode layer arranged on the surface of the current collector, wherein the composition of the electrode layer comprises an electrode active material and the impregnating compound.

It will be appreciated that the current collector has two surfaces opposite in the direction of its own thickness, and that the electrode layer is provided on either or both of the two surfaces.

In some embodiments, the mass percentage of the impregnating compound in the pole piece is 0.1% -0.5%. Specifically, the mass percent of the sizing agent includes, but is not limited to: 0.1%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.5%. Further, the mass percentage of the impregnating compound is 0.2% -0.4%.

In some embodiments, in the pole piece, the single-sided film weight of the electrode layer is more than or equal to 180mg/1540.25mm ². Further, the single-sided film weight of the electrode layer is 180mg/1540.25mm ²～250mg/1540.25mm ².

The application also provides a secondary battery comprising the pole piece.

The application also provides an electric device comprising a secondary battery selected from the group as described above.

The secondary battery and the power consumption device according to the present application will be described below with reference to the drawings.

In one embodiment of the present application, a secondary battery is provided.

In general, a secondary battery includes a positive electrode tab, a negative electrode tab, an electrolyte, and a separator. During the charge and discharge of the battery, active ions are inserted and extracted back and forth between the positive electrode plate and the negative electrode plate. The electrolyte plays a role in ion conduction between the positive electrode plate and the negative electrode plate. The isolating film is arranged between the positive pole piece and the negative pole piece, and mainly plays a role in preventing the positive pole piece and the negative pole piece from being short-circuited, and meanwhile ions can pass through the isolating film.

Positive electrode plate

The positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode film layer comprises the positive electrode active material of the first aspect of the application.

As an example, the positive electrode current collector has two surfaces opposing in its own thickness direction, and the positive electrode film layer is provided on either one or both of the two surfaces opposing the positive electrode current collector.

In some embodiments, the positive current collector may employ a metal foil or a composite current collector. For example, as the metal foil, aluminum foil may be used. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base layer. The composite current collector may be formed by forming a metal material on a polymeric material substrate. Wherein the metal material includes, but is not limited to, aluminum alloy, nickel alloy, titanium alloy, silver alloy, and the like. Polymeric substrates (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.)

In some embodiments, the positive electrode current collector has a thickness of 10 μm to 25 μm. Further, the thickness of the positive electrode current collector is 10 μm to 16 μm.

In some embodiments, the positive electrode active material may comprise a positive electrode active material for a battery as known in the art. As an example, the positive electrode active material may include at least one of the following materials: olivine structured lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material may be used. These positive electrode active materials may be used alone or in combination of two or more. Wherein, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (e.g., liCoO ₂), lithium nickel oxide (e.g., liNiO ₂), lithium manganese oxide (e.g., liMnO ₂、LiMn ₂O ₄), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi _1/3Co _1/3Mn _1/3O ₂ (which may also be abbreviated as NCM ₃₃₃)、LiNi _0.5Co _0.2Mn _0.3O ₂ (which may also be abbreviated as NCM ₅₂₃)、LiNi _0.5Co _0.25Mn _0.25O ₂ (which may also be abbreviated as NCM ₂₁₁)、LiNi _0.6Co _0.2Mn _0.2O ₂ (which may also be abbreviated as NCM ₆₂₂)、LiNi _0.8Co _0.1Mn _0.1O ₂ (which may also be abbreviated as NCM ₈₁₁)), lithium nickel manganese oxide (which may also be abbreviated as NCM ₃₃₃)、LiNi _0.5Co _0.2Mn _0.3O ₂ (which may also be abbreviated as NCM 42 examples of the olivine structured lithium-containing phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO ₄ (which may also be abbreviated as LFP)), a composite of lithium iron phosphate and carbon, a composite of lithium manganese phosphate (such as LiMnPO ₄), a composite of lithium manganese phosphate and carbon, a composite of lithium manganese phosphate, lithium iron phosphate, and a composite of lithium manganese phosphate and carbon.

In some embodiments, the positive electrode film layer further includes a binder. The adhesive in the pole piece is the same as that in the pole piece, and is not described in detail herein.

In some embodiments, the positive electrode film layer further optionally includes a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

In some embodiments, the positive electrode sheet may be prepared by: dispersing the components for preparing the positive electrode plate, such as the positive electrode active material, the conductive agent, the binder and any other components, in a solvent (such as N-methyl pyrrolidone) to form positive electrode slurry, wherein the solid content of the positive electrode slurry is 40-80wt%, the viscosity of the positive electrode slurry at room temperature is adjusted to 5000-25000 mPa.s, the positive electrode slurry is coated on the surface of a positive electrode current collector, and the positive electrode slurry is formed after being dried and cold-pressed by a cold rolling mill; the unit surface density of the positive electrode powder coating is 150-350mg/m ², the compacted density of the positive electrode plate is 3.0-3.6g/cm ³, and the compacted density of the positive electrode plate is 3.3-3.5g/cm ³. The calculation formula of the compaction density is

Compacted density = coated area density/(post-extrusion pole piece thickness-current collector thickness).

Negative pole piece

The negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, wherein the negative electrode film layer comprises a negative electrode active material.

As an example, the anode current collector has two surfaces opposing in its own thickness direction, and the anode film layer is provided on either one or both of the two surfaces opposing the anode current collector.

In some embodiments, the negative electrode current collector may employ a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base material. The composite current collector may be formed by forming a metal material on a polymeric material substrate. The metal material includes, but is not limited to, copper alloy, nickel alloy, titanium alloy, silver alloy, etc., and the polymer material substrate includes, but is not limited to, polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

In some embodiments, the negative electrode current collector has a thickness of 4 μm to 12 μm. Further, the thickness of the positive electrode current collector is 6 μm to 8 μm.

In some embodiments, the anode active material may employ an anode active material for a battery, which is well known in the art. As an example, the anode active material may include at least one of the following materials: artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like. The silicon-based material may be at least one selected from elemental silicon, silicon oxide, silicon nanowires, silicon oxygen compounds, silicon carbon composites, silicon nitrogen composites, and silicon alloys. The tin-based material may be at least one selected from elemental tin, tin oxide, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery anode active material may be used. These negative electrode active materials may be used alone or in combination of two or more.

In some embodiments, the negative electrode film layer further optionally includes a binder. The adhesive in the pole piece is the same as that in the pole piece, and is not described in detail herein.

In some embodiments, the negative electrode film layer further optionally includes a conductive agent. The conductive agent is at least one selected from superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

In some embodiments, the negative electrode film layer may also optionally include other adjuvants, such as thickening agents (e.g., sodium carboxymethyl cellulose (CMC-Na), lithium carboxymethyl cellulose (CMC-Li)), and the like. The weight ratio of the other auxiliary agents in the negative electrode film layer is 0-15% by weight based on the total weight of the negative electrode film layer.

In some embodiments, the negative electrode sheet may be prepared by: dispersing the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, in a solvent (such as deionized water) to form a negative electrode slurry, wherein the solid content of the negative electrode slurry is 30-70wt%, and the viscosity of the negative electrode slurry at room temperature is adjusted to 2000-10000 mPa.s; and (3) coating the obtained negative electrode slurry on a negative electrode current collector, and performing a drying procedure, cold pressing, such as a pair roller, to obtain a negative electrode plate. The unit area density of the negative electrode powder coating is 180-250 mg/1540.25mm ², and the compacted density of the negative electrode plate is 1.2-2.0 g/m ³.

Electrolyte composition

The electrolyte plays a role in ion conduction between the positive electrode plate and the negative electrode plate. The application is not particularly limited in the kind of electrolyte, and may be selected according to the need. For example, the electrolyte may be liquid, gel, or all solid.

In some embodiments, the electrolyte is an electrolyte. The electrolyte includes an electrolyte salt and a solvent.

In some embodiments, the electrolyte salt may be selected from one or more of lithium hexafluorophosphate (LiPF ₆), lithium tetrafluoroborate (LiBF ₄), lithium perchlorate (LiClO ₄), lithium hexafluoroarsenate (LiAsF ₆), lithium bis-fluorosulfonimide (LiFSI), lithium bis-trifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalato borate (lipfob), lithium dioxaato borate (LiBOB), lithium difluorophosphate (LiPO ₂F ₂), lithium difluorodioxaato phosphate (LiDFOP), and lithium tetrafluorooxalato phosphate (LiTFOP). The concentration of the electrolyte salt is usually 0.5 to 5mol/L.

In some embodiments, the solvent may be selected from one or more of fluoroethylene carbonate (FEC), ethylene Carbonate (EC), propylene Carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl Propyl Carbonate (MPC), ethylene Propyl Carbonate (EPC), butylene Carbonate (BC), methyl Formate (MF), methyl Acetate (MA), ethyl Acetate (EA), propyl Acetate (PA), methyl Propionate (MP), ethyl Propionate (EP), propyl Propionate (PP), methyl Butyrate (MB), ethyl Butyrate (EB), 1, 4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

In some embodiments, the electrolyte further optionally includes an additive. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives capable of improving certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high or low temperature performance of the battery, and the like.

Isolation film

In some embodiments, a separator is further included in the secondary battery. The type of the separator is not particularly limited, and any known porous separator having good chemical stability and mechanical stability can be used.

In some embodiments, the material of the isolating film may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of the respective layers may be the same or different, and are not particularly limited.

In some embodiments, the thickness of the separator is 6-40 μm, optionally 12-20 μm.

In some embodiments, the positive electrode tab, the negative electrode tab, and the separator may be manufactured into an electrode assembly through a winding process or a lamination process.

In some embodiments, the secondary battery may include an outer package. The outer package may be used to encapsulate the electrode assembly and electrolyte described above.

In some embodiments, the outer package of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, or the like. The exterior package of the secondary battery may also be a pouch type pouch, for example. The material of the flexible bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

The shape of the secondary battery is not particularly limited in the present application, and may be cylindrical, square, or any other shape. For example, fig. 1 is a secondary battery 5 of a square structure as one example.

In some embodiments, referring to fig. 2, the outer package may include a housing 51 and a cover 53. The housing 51 may include a bottom plate and a side plate connected to the bottom plate, where the bottom plate and the side plate enclose a receiving chamber. The housing 51 has an opening communicating with the accommodation chamber, and the cover plate 53 can be provided to cover the opening to close the accommodation chamber. The positive electrode tab, the negative electrode tab, and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is enclosed in the accommodating chamber. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, and those skilled in the art may select according to specific practical requirements.

In some embodiments, the secondary batteries may be assembled into a battery module, and the number of secondary batteries included in the battery module may be one or more, and the specific number may be selected by one skilled in the art according to the application and capacity of the battery module.

Fig. 3 is a battery module 4 as an example. Referring to fig. 3, in the battery module 4, a plurality of secondary batteries 5 may be sequentially arranged in the longitudinal direction of the battery module 4. Of course, the arrangement may be performed in any other way. The plurality of secondary batteries 5 may be further fixed by fasteners.

Alternatively, the battery module 4 may further include a case having an accommodating space in which the plurality of secondary batteries 5 are accommodated.

In some embodiments, the above battery modules may be further assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more, and a specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

Fig. 4 and 5 are battery packs 1 as an example. Referring to fig. 4 and 5, a battery case and a plurality of battery modules 4 disposed in the battery case may be included in the battery pack 1. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

In addition, the application also provides an electric device which comprises at least one of the secondary battery, the battery module or the battery pack. The secondary battery, the battery module, or the battery pack may be used as a power source of the power consumption device, and may also be used as an energy storage unit of the power consumption device. The power utilization device may include mobile devices (e.g., cell phones, notebook computers, etc.), electric vehicles (e.g., electric-only vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but is not limited thereto.

As the electricity consumption device, a secondary battery, a battery module, or a battery pack may be selected according to the use requirements thereof.

Fig. 6 is an electrical device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or the like. In order to meet the high power and high energy density requirements of the secondary battery by the power consumption device, a battery pack or a battery module may be employed.

As another example, the device may be a cell phone, tablet computer, notebook computer, or the like. The device is generally required to be light and thin, and a secondary battery can be used as a power source.

Examples

In order to make the technical problems, technical schemes and beneficial effects solved by the application more clear, the application will be further described in detail below with reference to the embodiments and the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be made by a person skilled in the art based on the embodiments of the application without any inventive effort, are intended to fall within the scope of the application.

The examples are not to be construed as limiting the specific techniques or conditions described in the literature in this field or as per the specifications of the product. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

Example 1:

The embodiment provides a negative electrode plate and a lithium ion secondary battery, and the preparation method thereof is as follows:

(1) Preparation of positive pole piece

Dissolving positive active materials lithium iron phosphate (LiFePO ₄), binder polyvinylidene fluoride (PVDF) and conductive agent acetylene black in a mass ratio of 97.3:2:0.7 into solvent N-methyl pyrrolidone (NMP), and fully stirring and uniformly mixing to obtain positive slurry; and coating, cold pressing and drying to obtain the positive pole piece. The coating weight was 400mg/1540.25mm ² and the slurry solids content was 63%. The positive current collector was aluminum foil 15 μm thick.

(2) Preparation of negative electrode plate

Dissolving negative active material artificial graphite, conductive agent acetylene black, binder Styrene Butadiene Rubber (SBR), thickener sodium carboxymethylcellulose (CMC-Na) and impregnating compound 1 in a mass ratio of 96.4 percent to 0.7 percent to 1.5 percent to 1.2 percent to 0.2 percent in solvent deionized water, and fully stirring and uniformly mixing to obtain negative slurry; the negative pole piece is prepared after coating, drying and cold pressing, the solid content of the slurry is 53%, and the weight of the pole piece is 200mg/1540.25mm ². The negative electrode current collector was aluminum foil 7 μm thick. Wherein the weight average molecular weight of the binder Styrene Butadiene Rubber (SBR) is 200000 and the solid content is 48 percent.

(3) Lithium ion secondary battery preparation

And sequentially laminating the positive electrode plate, a polyethylene film with the thickness of 14 mu m serving as an isolating film and the negative electrode plate, so that the isolating film is positioned between the positive electrode plate and the negative electrode plate to play a role of isolation, and winding to obtain the bare cell. The bare cell is placed in an outer package, and electrolyte is injected into the dried battery, and the lithium ion battery of the embodiment 1 is obtained after the procedures of vacuum packaging, standing, formation, shaping and the like.

The impregnating compound 1 has the structure that:

The preparation method of the impregnating compound 1 comprises the following steps: 1.1mol of valeric acid reacts with 1mol of 2-amino-2-phenylacetic acid and 0.1gZn of powder at 130 ℃ for 6 hours, and intermediate 1 is obtained by distillation and suction filtration; 1mol of intermediate 1 and 1.15mol of 2-butylamine are catalyzed by 0.1gZn powder and react for 3 hours at 45 ℃, and the impregnating compound 1 is obtained after distillation and suction filtration.

The infrared spectrum is shown in fig. 7: as can be seen from the infrared spectrum, 1500-1670 has characteristic peaks of benzene rings, pi-pi conjugation between benzene rings self-assembles in one-dimensional direction to form a network, a three-dimensional network is further constructed, electrolyte is constrained to construct a lithium ion high-speed channel, 1630-1690 and 3300-3500 have characteristic peaks of amide bonds, rapid infiltration of the electrolyte is realized, and lithium ion migration is accelerated.

Example 2:

The present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as that of embodiment 1, and the main differences are: the negative electrode active material comprises 96.3% of artificial graphite, 0.7% of conductive agent acetylene black, 1.5% of binder Styrene Butadiene Rubber (SBR), 1.2% of thickener sodium carboxymethylcellulose (CMC-Na) and 0.3% of impregnating compound 1 by mass. The solid content of the cathode slurry is 53%, and the weight of the pole piece is 200mg/1540.25mm ².

Example 3:

the present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as embodiment 1, and the main difference is that: the mass ratio of the negative electrode active material artificial graphite to the conductive agent acetylene black to the binder styrene-butadiene rubber (SBR), the thickener sodium carboxymethylcellulose (CMC-Na) to the impregnating compound 1 is 96.2 percent to 0.7 percent to 1.5 percent to 1.2 percent to 0.4 percent. The solid content of the cathode slurry is 53%, and the weight of the pole piece is 200mg/1540.25mm ².

Example 4:

The present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as that of embodiment 1, and the main difference is that the preparation method of the negative electrode sheet is as follows:

Mixing artificial graphite, conductive carbon and a binder 1 in a double-planetary mixer to obtain solvent-free particles, mixing an impregnating compound 1, a binder 2 and deionized water to obtain a glue solution, kneading the solvent-free particles and the glue solution to obtain a bulk material, conveying the bulk material by a screw, extruding the bulk material into a thick sheet by a die head, rolling and thinning the thick sheet, and compositing the thick sheet with a current collector to obtain the negative electrode plate. The mass ratio of the artificial graphite, the conductive carbon, the binder 1 (PTFE), the binder 2 (acrylic acid/acrylonitrile/acrylamide copolymer) and the sizing agent 1 is 97.0 percent, 0.7 percent, 0.1 percent, 2 percent and 0.2 percent. The solid content of the cathode slurry is 70%, and the weight of the pole piece is 200mg/1540.25mm ².

Wherein the weight average molecular weight of the binder 1 is 2000 ten thousand, and the SSG is 2.19; binder 2, weight average molecular weight 350000, solids content 5.5%. The preparation method of the adhesive 2 can be referred to as follows: the polymerization is carried out on an anionic polymerization apparatus (for example, HTSCP series, SCP 2009) under a pressure of 0.3 to 0.5MPa, with high-pressure nitrogen protection. In the reaction process, a nucleophilic reagent is used as an initiator. The monomer acrylic acid, the acrylonitrile and the acrylamide are added in sequence, and react for 50min at the temperature of 25-40 ℃, and the chain reaction is terminated by adding alcohols, wherein the mole percentage of the three monomers is 40%:30%:30%.

Example 5:

The present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as that of embodiment 4, and the main difference is that: the mass ratio of the artificial graphite, the conductive carbon, the binder 1 (PTFE), the binder 2 (acrylic acid/acrylonitrile/acrylamide copolymer) and the sizing agent 1 is 96.9 percent, 0.7 percent, 0.1 percent, 2 percent and 0.3 percent. The solid content of the cathode slurry is 70%, and the weight of the pole piece is 200mg/1540.25mm ².

Example 6:

The present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as that of embodiment 4, and the main difference is that: the mass ratio of the artificial graphite, the conductive carbon, the binder 1 (PTFE), the binder 2 (acrylic acid/acrylonitrile/acrylamide copolymer) and the sizing agent 1 is 96.8 percent, 0.7 percent, 0.1 percent, 2 percent and 0.4 percent. The solid content of the cathode slurry is 70%, and the weight of the pole piece is 200mg/1540.25mm ².

Example 7:

the present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as embodiment 1, and the main difference is that: and replacing the impregnating compound 1 with the impregnating compound 2. In the chemical structure of the impregnating compound 2, R ₁ is substituted by ester groups, and the structure is as follows:

The preparation method of the impregnating compound 2 comprises the following steps: hydrolyzing 1.15mol diethyl malonate to remove one ester group, reacting with 1mol 2-amino 2-phenylacetic acid and 0.1gZn powder at 80 ℃ for 10 hours, distilling, suction filtering to obtain intermediate 2, reacting 1mol intermediate 2 with 1.2mol propylamine at 0.1gZn powder for 5 hours at 60 ℃, distilling, and suction filtering to obtain sizing agent 2.

Example 8:

the present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as embodiment 1, and the main difference is that: and replacing the impregnating compound 1 with the impregnating compound 3. In the chemical structure of the impregnating compound 3, R ₁ is substituted by alkoxy, and the structure is as follows:

The preparation method of the impregnating compound 3 comprises the following steps: 1.15mol of ethoxyacetic acid and 1mol of 2-amino-2-phenylacetic acid, 0.1gZn powder react for 10 hours at 80 ℃, intermediate 3 is obtained by distillation and suction filtration, 1mol of intermediate 3 and 1.15mol of ethylamine are catalyzed by 0.1gZn powder and react for 3 hours at 45 ℃, and impregnating compound 3 is obtained by distillation and suction filtration.

Example 9:

The present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as embodiment 1, and the main difference is that: the impregnating compound 1 is replaced by the impregnating compound 4. In the chemical structure of the impregnating compound 4, R ₁ is substituted by alkenyl, and the structure is as follows:

The preparation method of the impregnating compound 4 comprises the following steps: 1.2mol of vinyl acetic acid and 1mol of 2-amino-2-phenyl acetic acid, 0.1gZn powder react for 8 hours at 100 ℃, intermediate 4 is obtained by distillation and suction filtration, 1mol of intermediate 4 and 1.15mol of methylamine are catalyzed by 0.1gZn powder and react for 3 hours at 60 ℃, and impregnating compound 4 is obtained by distillation and suction filtration.

Example 10:

the present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as embodiment 1, and the main difference is that: the impregnating compound 5 is used for replacing the impregnating compound 1. In the chemical structure of the impregnating compound 5, R ₁ is substituted by a phosphate group, and the structure is as follows:

The preparation method of the impregnating compound 5 comprises the following steps: 1.2mol of triethyl phosphorylacetate is hydrolyzed to remove one ester group, then reacted with 1mol of 2-amino-2-phenylacetic acid and 0.1gZn powder at 130 ℃ for 10 hours, distilled and suction filtered to obtain an intermediate 5,1mol of intermediate 4 is catalyzed with 1.1mol of butylamine at 0.1gZn powder, reacted at 60 ℃ for 3 hours, distilled and suction filtered to obtain the impregnating compound 5.

Example 11:

The present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as embodiment 1, and the main difference is that: the negative electrode active material comprises, by mass, 96% of artificial graphite, 0.7% of conductive agent acetylene black, 1.5% of binder styrene-butadiene rubber (SBR), 1.2% of thickener sodium carboxymethylcellulose (CMC-Na) and 0.6% of impregnating compound 1. The solid content of the cathode slurry is 53%, and the weight of the pole piece is 200mg/1540.25mm ².

Comparative example 1

This comparative example provides a negative electrode tab and a lithium ion secondary battery, which are prepared by the same method as example 1, and are mainly different in that: the negative electrode active material artificial graphite, the conductive agent acetylene black, the binder Styrene Butadiene Rubber (SBR) and the thickener sodium carboxymethylcellulose (CMC-Na) are not added with the impregnating compound 1, and the mass ratio is 96.6 percent, 0.7 percent, 1.5 percent and 1.2 percent. The solid content of the cathode slurry is 53%, and the weight of the pole piece is 200mg/1540.25mm ².

Comparative example 2

This comparative example provides a negative electrode tab and a lithium ion secondary battery, which are prepared by the same method as example 4, and are mainly different in that: the mass ratio of the artificial graphite, the conductive carbon, the binder 1 (PTFE) and the binder 2 (acrylic acid/acrylonitrile/acrylamide copolymer) is 97.2 percent to 0.7 percent to 0.1 percent to 2 percent without adding the impregnating compound 1. The solid content of the cathode slurry is 70%, and the weight of the pole piece is 200mg/1540.25mm ².

Comparative example 3

The present embodiment provides a negative electrode sheet and a lithium ion secondary battery, and the preparation method thereof is the same as embodiment 1, and the main difference is that: the contrast sizing agent was used in place of sizing agent 1. The comparative impregnating compound was prepared in the same manner as in example 1, and its chemical structure was as follows:

The lithium ion batteries prepared in the examples and comparative examples were tested as follows:

(1) Lithium evolution test

The constant current charging of the 1C current is carried out to 3.65V, then the constant voltage charging is carried out to 0.05C under 3.65V, the standing is carried out for 5min, then the constant current discharging is carried out to 2.5V under 1C current, the charging and discharging cycle is carried out for the battery, and after 10 circles of cycles, the constant voltage charging is carried out to 0.05C under 3.65V. And disassembling the battery in a dry environment, wherein the golden color on the surface of the negative electrode plate indicates that the battery is not analyzed, and the silvery white area indicates that the battery is analyzed.

(2) Electrolyte infiltration rate test

The testing method comprises the following steps: a certain amount of electrolyte (2 cm in height) is sucked by a capillary (1 mm in diameter) so that the liquid sucking end of the capillary is contacted with the surface of the electrode plate. The electrode pole piece is of a porous structure, electrolyte in the capillary tube can be sucked out under the action of capillary force, and the time required by complete absorption of the electrolyte is recorded, so that the electrolyte infiltration rate is obtained through calculation.

The electrolyte infiltration rate calculation method comprises the following steps: electrolyte density the volume of electrolyte in the capillary/time required for the electrolyte to be fully absorbed. The test results are shown in Table 1.

(3) DCR performance test

The testing method comprises the following steps: at 25 ℃,0.33C is charged to a full charge state, then 0.33C is discharged for 0.5Cn (Cn represents battery capacity) to adjust the secondary battery to 50% soc, and the secondary battery is left for 30 minutes, after which 3C is discharged for 30 seconds at a voltage V1 at rest, after which 3C is discharged for 30 seconds at a voltage V2 at rest, after which 3C is discharged for 30 seconds, left for 40 seconds, and 3C is charged for 30 seconds;

The calculation method comprises the following steps: dcr= (V1-V2)/I, where V1 stands still to end voltage, V2 discharge cut-off voltage, I is discharge current. The test results are shown in Table 1.

(4) Rate capability test

Multiplying power discharge: charging 0.33C to 3.65V constant voltage to current of 0.05C, standing for 5 min, discharging 0.33C to 2.5V and measuring discharge capacity therebetween, and standing for 30 min; charging 0.33C to 3.65V constant voltage to current of 0.05C, standing for 5 min, discharging 1C to 2.5V and measuring discharge capacity therebetween, and standing for 30 min; charging 0.33C to 3.65V constant voltage to current of 0.05C, standing for 5 min, discharging 3C to 2.8V and measuring discharge capacity therebetween, and standing for 30 min; charging 0.33C to 3.65V constant voltage to current of 0.05C, standing for 5 minutes, discharging 5C to 2.5V and measuring discharge capacity therebetween, and standing for 30 minutes.

Multiplying power charging: charging 0.33C to 3.65V constant voltage to current of 0.05C, standing for 5 min, discharging 0.33C to 2.5V, and measuring charging capacity therebetween, standing for 30 min; charging 1C to 3.65V constant voltage to current of 0.05C, standing for 30 min, discharging 0.33C to 2.5V and measuring charge capacity therebetween, standing for 30 min; 3C charging 3.65V constant voltage charging to current of 0.05C, standing for 5 min, 0.33C discharging to 2.5V and measuring charging capacity therebetween, standing for 30 min; 5C was charged to a constant voltage of 4.2V to a current of 0.05C, left standing for 30 minutes, 0.33C was discharged to 2.5V and the charge capacity therebetween was measured, and left standing for 30 minutes.

The test results are shown in tables 1-2 below:

Table 1 comparative examples pole piece preparation and performance comparison

Table 2 comparative examples and examples multiplying power can be compared

The present application is not limited to the above embodiment. The above embodiments are merely examples, and embodiments having substantially the same configuration and the same effects as those of the technical idea within the scope of the present application are included in the technical scope of the present application. Further, various modifications that can be made to the embodiments and other modes of combining some of the constituent elements in the embodiments, which are conceivable to those skilled in the art, are also included in the scope of the present application within the scope not departing from the gist of the present application.

Claims (20)

1. An amide compound having the structural features shown below:

   Wherein R ₁ is C1-C15 alkyl substituted or unsubstituted with one or more R ₀;

   R ₂ is C1-C15 alkyl substituted or unsubstituted with one or more R ₀;

   R ₀ is independently selected from one of the following substituents for each occurrence: H. a heterocyclic group of C3-C8, a sulfonate group of C1-C8, an ester group of C1-C8, a phosphate group of C1-C8, an alkoxy group of C1-C8, an alkylthio group of C1-C8, an alkenyl group of C2-C8 and an alkynyl group of C2-C8.
2. The amide compound according to claim 1, wherein R ₂ is an unsubstituted C1 to C15 alkyl group; optionally, R ₂ is unsubstituted C1-C8 alkyl; further alternatively, R ₂ is unsubstituted C1-C5 alkyl.
3. The amide compound according to claim 1 or 2, wherein R ₁ is C1-C10 alkyl substituted or unsubstituted with one or more R ₀; optionally, R ₁ is C1-C6 alkyl substituted or unsubstituted with one or more R ₀.
4. An amide compound according to any of claims 1-3, wherein R ₀ is independently selected from one of the following substituents for each occurrence: sulfonate group of C1-C5, ester group of C1-C5, phosphate group of C1-C5, alkoxy group of C1-C5, alkylthio group of C1-C5, alkenyl group of C2-C5 and alkynyl group of C2-C5.
5. The amide-based compound according to any one of claims 1 to 4, wherein R ₀ is each occurrence independently selected from one of the substituents of the group consisting of:
6. The amide-based compound according to any one of claims 1 to 5, wherein the amide-based compound is selected from one of the following compounds:
7. The preparation method of the amide compound is characterized by comprising the following steps of:

   Carrying out amidation reaction on the compound 1 and the compound 2 to prepare an intermediate 1;

   Carrying out amidation reaction on the intermediate 1 and the compound 3 to prepare the amide compound;

   Or, carrying out amidation reaction on the compound 1 and the compound 3 to prepare an intermediate 2;

   Carrying out amidation reaction on the intermediate 2 and the compound 2 to prepare the amide compound;

   wherein the structures of compound 1, compound 2, compound 3, intermediate 1 and intermediate 2 are as follows:
8. a sizing agent characterized in that the composition thereof comprises one or more of the amide compounds as shown in any one of claims 1 to 6.
9. A pole piece slurry comprising an electrode active material, the sizing agent of claim 8, and a solvent.
10. The pole piece slurry according to claim 9, wherein the mass percentage of the impregnating compound in the pole piece slurry is 0.1% -0.5%; optionally, the mass percentage of the impregnating compound is 0.2% -0.4%.
11. A pole piece slurry according to claim 9 or 10, characterized in that the solvent comprises one or more of water, an alcoholic solvent and an ester solvent; optionally, the alcoholic solvent comprises one or more of 1, 3-propanediol, 1, 2-propanediol, 1, 4-butanediol, and 1, 3-butanediol; optionally, the ester solvent includes one or more of triethyl phosphate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and propylene carbonate.
12. The pole piece slurry according to any of claims 9-11, characterized in that the pole piece slurry further comprises a binder; optionally, the binder comprises one or more of styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid and carboxymethyl chitosan, or the binder comprises one or more of polytetrafluoroethylene, acrylonitrile, copolymer of acrylic acid and acrylamide, or copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, copolymer of tetrafluoroethylene and hexafluoropropylene, and copolymer of poly (chlorotrifluoroethylene), ethylene and chlorotrifluoroethylene.
13. The pole piece slurry of claim 12, wherein the binder comprises a first binder and a second binder;

    Optionally, the first binder comprises one or more of polytetrafluoroethylene, tetrafluoroethylene and perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene and hexafluoropropylene copolymer, and polytrifluoroethylene, ethylene and chlorotrifluoroethylene copolymer, preferably polytetrafluoroethylene; further alternatively, the first binder has a weight average molecular weight greater than ten million and an SSG of 2.13 to 2.19; still further alternatively, in the pole piece slurry, the mass percentage of the first binder is 0.05% -0.5%;

    Optionally, the second binder comprises a copolymer of one or more of acrylonitrile, acrylic acid, and polyamide; further alternatively, the molecular weight of the second binder is more than 300000, and the solid content is 4% -7%; still further alternatively, the mass percentage of the second binder in the pole piece slurry is 0.5% -4%.
14. The pole piece slurry of any of claims 9 to 13, wherein the solid content of the pole piece slurry is 65% to 85%.
15. The preparation method of the pole piece is characterized by comprising the following steps:

    an electrode layer is prepared by applying the electrode sheet slurry of any one of claims 9 to 14 to the surface of a current collector.
16. The method of preparing a pole piece of claim 15, wherein the step of preparing an electrode layer on the surface of a current collector using the pole piece slurry comprises:

    Shaping the pole piece slurry to prepare a membrane;

    And compounding the membrane with the current collector.
17. A pole piece comprising a current collector and an electrode layer disposed on a surface of the current collector, the electrode layer comprising an electrode active material and the sizing agent of claim 8.
18. The pole piece of claim 17, characterized in that it has at least one of the following features:

    (1) The mass percentage of the impregnating compound is 0.1% -0.5%; optionally, the mass percentage of the impregnating compound is 0.2% -0.4%;

    (2) The weight of the single-sided film layer of the electrode layer is more than or equal to 180mg/1540.25mm ²; optionally, the single-sided film weight of the electrode layer is 180mg/1540.25mm ²～250mg/1540.25mm ².
19. A secondary battery comprising the pole piece of claim 17 or 18.
20. An electric device comprising a secondary battery selected from the group consisting of claim 19.