CN115819690A

CN115819690A - Polymer, preparation method and application thereof, secondary battery, battery module, battery pack and electric device

Info

Publication number: CN115819690A
Application number: CN202210517069.6A
Authority: CN
Inventors: 林江辉; 赵延杰; 李星; 金海族
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2023-03-21

Abstract

The present application relates to the field of secondary battery technology, and in particular, to a polymer, a method for preparing the same, an application thereof, a secondary battery, a battery module, a battery pack, and an electric device. The application provides a polymer that contains azido, it has the shown structure of formula I, and this polymer has stronger appeal to electrolyte solvent molecule commonly used, adsorbs electrolyte easily, consequently, this polymer can add in anodal active material layer to improve the adsorption affinity of positive pole piece to electrolyte, can effectively promote the ionic conduction ability of battery, and then promote the batteryAnd (4) cycle performance.

Description

Polymer, preparation method and application thereof, secondary battery, battery module, battery pack and electric device

Technical Field

The present application relates to the field of secondary battery technology, and in particular, to a polymer, a method for preparing the same, an application thereof, a secondary battery, a battery module, a battery pack, and an electric device.

Background

Due to the non-renewable and rapid consumption of petroleum resources in a short period and the aggravation of environmental pollution, various industries search green and environment-friendly new energy sources capable of replacing or partially replacing the petroleum resources. As a field with large consumption of petroleum resources, the automobile industry is also dedicated to developing greener and more environment-friendly electric automobiles to replace part of the market of oil automobiles. However, in the conventional technology, the problem of poor electron conductivity and ion conductivity of the cathode material used for the secondary battery, typically a lithium ion battery, affects the rate performance, low temperature performance and long-term cycling stability of the battery, which obviously greatly limits the application of the battery in high-demand electric devices such as electric vehicles.

Disclosure of Invention

Based on this, it is necessary to provide a polymer, a preparation method and applications thereof, a secondary battery, a battery module, a battery pack and an electric device, wherein the polymer can be used as a positive electrode additive, so as to solve the problem of poor electron conductivity and ion conductivity of a positive electrode material in the prior art, and further improve the rate capability, low-temperature performance and long-term cycling stability of the battery.

In a first aspect of the present application, there is provided an azido-containing polymer having the structure of formula I:

wherein, each occurrence of A is independently selected from-C (R) ⁹ R ¹⁰ )-、-NR ¹¹ -, -O-, -S-, or-C (= O) -or-S (= O) -;

R ¹ ～R ¹¹ each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, halogen, unsubstituted or R ¹² Substituted C _1～ C ₆ Alkyl, unsubstituted or R ¹³ Substituted C _1～ C ₆ Alkoxy, unsubstituted or R ¹⁴ Substituted C _2～ C ₆ Alkenyl, unsubstituted or R ¹⁵ Substituted aryl with 6-20 ring atoms, unsubstituted or R ¹⁶ A substituted heteroaryl group having 5 to 20 ring atoms;

R ¹² ～R ¹⁶ each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, halo, methyl, ethyl, methoxy or phenyl;

m and n are positive integers and m/n =1 to 100; preferably, m/n =50 to 100.

Among the technical scheme of this application, through designing the molecule, provide the polymer that contains azide group that formula I is shown, this polymer has stronger appeal to electrolyte solvent molecule commonly used, adsorbs electrolyte easily, consequently, this polymer can add in anodal active material layer to improve the adsorption affinity of positive pole piece to electrolyte, can effectively promote the ion-conducting capacity of battery, and then promote the circulation performance of battery.

In some embodiments, the value ranges of m and n are respectively: m is more than or equal to 500 and less than or equal to 10000, n is more than or equal to 10 and less than or equal to 10000;

preferably, 1000. Ltoreq. M.ltoreq.10000, 20. Ltoreq. N.ltoreq.5000;

further preferably, 3000. Ltoreq. M.ltoreq.7000, 30. Ltoreq. N.ltoreq.1500;

still more preferably, 4500. Ltoreq. M.ltoreq.6000, 40. Ltoreq. N.ltoreq.200.

By controlling the number of the polymerization units in the molecular structure of the polymer within a proper range, the affinity of the polymer to electrolyte can be effectively improved, and other performances of the battery are not negatively affected.

In some embodiments, said a, for each occurrence, is independently selected from-CH ₂ -, -NH-or-O-;

preferably, said a, for each occurrence, is independently selected from-NH-or-O-;

further preferably, said a is selected from-O-.

In some embodiments, the R is ¹ ～R ² Each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstitutedC _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, said R is ¹ ～R ² Each occurrence is independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indolyl or carbazolyl;

further preferably, said R ¹ ～R ² Each occurrence is independently selected from-H or methyl.

In some embodiments, the R is ⁵ Each occurrence is independently selected from-H, -D, -OH, -NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, said R is ⁵ Each occurrence is independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indolyl or carbazolyl;

further preferably, said R ⁵ Each occurrence is independently selected from-H, methyl, ethyl, n-propyl or isopropyl.

In some embodiments, the R is ³ ～R ⁴ 、R ⁶ ～R ¹¹ Each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, said R is ³ ～R ⁴ 、R ⁶ ～R ¹¹ Each occurrence is independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indolyl or carbazolyl;

further preferably, said R ³ ～R ⁴ 、R ⁶ ～R ¹¹ Each occurrence is independently selected from-H.

In a second aspect of the present application, there is provided a polymer comprising a conductive carbon material having the structure of formula II:

wherein, A and R ¹ ～R ¹⁶ M and n are as defined in any one of claims 1 to 6;

x is independently selected from-C (R) at each occurrence ¹⁷ R ¹⁸ )-、

* Represents a linking site;

R ¹⁷ ～R ²⁸ each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, halogen, unsubstituted or R ²⁹ Substituted C _1～ C ₆ Alkyl, unsubstituted or R ³⁰ Substituted C _1～ C ₆ Alkoxy, unsubstituted or R ³¹ Substituted C _2～ C ₆ Alkenyl, unsubstituted or R ³² Substituted aryl with 6-20 ring atoms, unsubstituted or R ³³ A substituted heteroaryl group having 5 to 20 ring atoms;

R ²⁹ ～R ³³ each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, halo, methyl, ethyl, methoxy or phenyl;

represents a conductive carbon material.

The conductive carbon material is introduced into the branched chain in the polymer shown in the formula II, so that when the polymer is added into the positive active material layer, the adsorption capacity of the positive pole piece to the electrolyte can be improved, the ion conduction capacity and the cycle performance of the battery are improved, and the electron conduction capacity of the battery can be effectively improved. When m/n is larger, the affinity to electrolyte is strong, the ion conducting capability of the pole piece is strong, but the electron conducting capability is poorer because n is smaller and the number of connected conductive carbon units is less; on the contrary, when m/n is smaller, the improvement of the ion conducting capability of the pole piece is limited, but the ion conducting capability is stronger. Therefore, the battery performance can be improved to the maximum extent only by balancing the ion and electron conducting capabilities of the pole piece and adjusting the m/n value within a proper range.

In some embodiments, each occurrence of X is independently selected from-CH ₂ -、-CH ₂ -CH ₂ -or-CH ₂ -CH ₂ -CH ₂ -；

Preferably, said X is, for each occurrence, independently selected from-CH ₂ -or-CH ₂ -CH ₂ -；

Further preferably, X is selected from-CH ₂ -。

In some embodiments, the compound has a structure represented by formula II-0:

wherein R is ² Each occurrence is independently selected from-H or methyl, R ⁵ Each occurrence is independently selected from-H, methyl, ethyl, n-propyl or isopropyl.

In some embodiments, the conductive carbon material comprises one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The polymer shown in the formula II can be compatible with various conventional conductive carbon materials, and has a wide application prospect.

In a third aspect of the present application, there is provided the use of the azide-containing polymer described in one or more of the foregoing embodiments and/or the conductive carbon material-containing polymer described in one or more of the foregoing embodiments in the preparation of a secondary battery.

In a fourth aspect of the present application, a secondary battery is provided, which includes a negative electrode plate, an isolation film and a positive electrode plate, wherein the isolation film is disposed between the negative electrode plate and the positive electrode plate;

the positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer comprises a positive electrode additive, and the positive electrode additive comprises the polymer containing azide groups in one or more of the previous embodiments and/or the polymer containing conductive carbon materials in one or more of the previous embodiments.

In some embodiments, the positive active material layer further comprises a positive active material comprising one or more of a lithium-rich manganese-based positive electrode material, a nickel-cobalt-manganese ternary positive electrode material, a lithium iron phosphate positive electrode material, a lithium cobalt oxide positive electrode material, a lithium manganese oxide positive electrode material, and a lithium titanate positive electrode material.

In some embodiments, the positive electrode additive is present in the positive electrode active material layer in an amount of 1 to 5% by mass;

preferably, the mass percentage of the positive electrode additive in the positive electrode active material layer is 1-3%. The dosage of the positive electrode additive is controlled within a proper range, so that the conductive and ion conductive capabilities of the battery can be improved, and meanwhile, the impedance of the battery cannot be increased, and the energy density cannot be reduced.

In some embodiments, the positive electrode additive is coated on the surface of the positive electrode active material. The particle size of the commonly used anode active material is from several micrometers to tens of micrometers, and the prepared anode additive can form nano-grade coating on the surface of the anode active material, so that the conductive ability and the ion conductive ability of the battery are effectively improved, and the adverse effect on the activity performance of the anode active material is avoided.

In a fifth aspect of the present application, there is provided a battery module including the secondary battery described in one or more of the foregoing embodiments.

In a sixth aspect of the present application, there is provided a battery pack including the aforementioned battery module.

In a seventh aspect of the present application, there is provided an electric device including one or more of the secondary battery, the battery module, and the battery pack described in one or more of the foregoing embodiments.

In an eighth aspect of the present application, there is provided a method for preparing an azide-containing polymer described in one or more of the foregoing embodiments, comprising the steps of:

carrying out polymerization reaction on the compound shown as the formula I-1-2 to obtain a polymer shown as the formula I-1-1;

carrying out polymerization reaction on the polymer shown in the formula I-1-1 and the compound shown in the formula I-2-1 to obtain the polymer containing the azide group shown in the formula I;

in a ninth aspect of the present application, there is provided a method for preparing a polymer containing an electrically conductive carbon material as described in one or more of the foregoing embodiments, comprising the steps of:

performing cycloaddition reaction on the polymer containing the azido group shown in the formula I and the compound shown in the formula II-1 to obtain the polymer containing the azido group shown in the formula II;

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 the 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 diagram of a battery pack according to an embodiment of the present application.

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

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

Description of reference numerals:

1, a battery pack; 2, putting the box body on the box body; 3, discharging the box body; 4 a battery module; 5 a secondary battery; 51 a housing; 52 an electrode assembly; 53 cover plate.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are shown in the drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise. In the description of the present application, "a number" means at least one, such as one, two, etc., unless specifically limited otherwise.

Unless defined otherwise, all 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. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the present application, the technical features described in the open form include a closed technical solution including the listed features, and also include an open technical solution including the listed features.

In the present application, reference is made to numerical ranges which are considered to be continuous within the numerical ranges, unless otherwise specified, and which include the minimum and maximum values of the range, as well as each and every value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range-describing features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein.

The percentage contents referred to in the present application mean, unless otherwise specified, mass percentages for solid-liquid mixing and solid-solid phase mixing, and volume percentages for liquid-liquid phase mixing.

The percentage concentrations referred to in this application, unless otherwise indicated, refer to the final concentrations. The final concentration refers to the ratio of the additive component in the system to which the component is added.

The temperature parameter in the present application is not particularly limited, and may be a constant temperature treatment or a treatment within a certain temperature range. The constant temperature process allows the temperature to fluctuate within the accuracy of the instrument control.

m and n are positive integers and m/n =1 to 100; preferably, m/n =50 to 100.

The term "alkyl" refers to a saturated hydrocarbon containing a primary (normal) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof. Phrases containing the term, e.g., "C ₁ ～C ₆ Alkyl "means an alkyl group containing from 1 to 6 carbon atoms, which at each occurrence may be independently of each other C ₁ Alkyl radical, C ₂ Alkyl radical, C ₃ Alkyl radical, C ₄ Alkyl radical, C ₅ Alkyl or C ₆ An alkyl group. Suitable examples include, but are not limited to: methyl (Me, -CH) ₃ ) Ethyl (Et-CH) ₂ CH ₃ ) 1-propyl (n-Pr, n-propyl, -CH) ₂ CH ₂ CH ₃ ) 2-propyl (i-Pr, i-propyl, isopropyl, -CH (CH) ₃ ) ₂ ) 1-butyl (n-Bu, n-butyl, -CH) ₂ CH ₂ CH ₂ CH ₃ ) 2-methyl-1-propyl (i-Bu, i-butyl, -CH) ₂ CH(CH ₃ ) ₂ ) 2-butyl (s-Bu, s-butyl, -CH (CH) ₃ )CH ₂ CH ₃ ) 2-methyl-2-propyl (t-Bu, t-butyl, -C (CH) ₃ ) ₃ ) 1-pentyl (n-pentyl, -CH) ₂ CH ₂ CH ₂ CH ₂ CH ₃ ) 2-pentyl (-CH (CH 3) CH2CH2CH 3), 3-pentyl (-CH (CH) ₂ CH ₃ ) ₂ ) 2-methyl-2-butyl (-C (CH) ₃ ) ₂ CH ₂ CH ₃ ) 3-methyl-2-butyl (-CH (CH) ₃ )CH(CH ₃ ) ₂ ) 3-methyl-1-butyl (-CH) ₂ CH ₂ CH(CH ₃ ) ₂ ) 2-methyl-1-butyl (-CH) ₂ CH(CH ₃ )CH ₂ CH ₃ ) 1-hexyl (-CH) ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ) 2-hexyl (-CH (CH) ₃ )CH ₂ CH ₂ CH ₂ CH ₃ ) 3-hexyl (-CH (CH) ₂ CH ₃ )(CH ₂ CH ₂ CH ₃ ) 2-methyl-2-pentyl (-C (CH)) ₃ ) ₂ CH ₂ CH ₂ CH ₃ ) 3-methyl-2-pentyl (-CH (CH) ₃ )CH(CH ₃ )CH ₂ CH ₃ ) 4-methyl-2-pentyl (-CH (CH) ₃ )CH ₂ CH(CH ₃ ) ₂ ) 3-methyl-3-pentyl (-C (CH) ₃ )(CH ₂ CH ₃ ) ₂ ) 2-methyl-3-pentyl (-CH (CH) ₂ CH ₃ )CH(CH ₃ ) ₂ ) 2, 3-dimethyl-2-butyl (-C (CH) ₃ ) ₂ CH(CH ₃ ) ₂ ) And 3, 3-dimethyl-2-butyl (-CH (CH) ₃ )C(CH ₃ ) ₃ 。

The term "alkoxy" refers to a group having an-O-alkyl group, i.e., an alkyl group as defined above attached to the parent core structure via an oxygen atom. Phrases containing the term, e.g., "C ₁ ～C ₆ Alkoxy "means that the alkyl moiety contains from 1 to 6 carbon atoms and, for each occurrence, may be independently C ₁ Alkoxy radical, C ₄ Alkoxy radical, C ₅ Alkoxy or C ₆ An alkoxy group. Suitable examples include, but are not limited to: methoxy (-O-CH) ₃ or-OMe), ethoxy (-O-CH) ₂ CH ₃ or-OEt) and tert-butoxy (-O-C (CH) ₃ ) ₃ or-OtBu).

The term "alkenyl" is meant to encompass compounds having at least one site of unsaturation, i.e., carbon-Carbon sp ² A hydrocarbon of a positive carbon atom, a secondary carbon atom, a tertiary carbon atom or a ring carbon atom of a double bond. Phrases containing the term, e.g., "C ₂ ～C ₆ Alkenyl "means an alkenyl group containing 2 to 6 carbon atoms and, at each occurrence, may be independently C ₂ Alkenyl radical, C ₃ Alkenyl radical, C ₄ Alkenyl radical, C ₅ Alkenyl or C ₆ An alkenyl group. Suitable examples include, but are not limited to: vinyl (-CH = CH) ₂ ) Allyl (-CH) ₂ CH＝CH ₂ ) Cyclopentenyl (-C) ₅ H ₇ ) And 5-hexenyl (-CH) ₂ CH ₂ CH ₂ CH ₂ CH＝CH ₂ )。

The term "aryl" refers to an aromatic hydrocarbon group derived by removing one hydrogen atom from an aromatic ring compound, and may be a monocyclic aromatic group, or a fused ring aromatic group, or a polycyclic aromatic group, at least one of which is an aromatic ring system for polycyclic ring species. For example, "C ₅ ～C ₂₀ Aryl "means an aryl group containing from 5 to 20 carbon atoms, which may be, independently for each occurrence, C ₅ Aryl radical, C ₆ Aryl radical, C ₁₀ Aryl radical, C ₁₄ Aryl radical, C ₁₈ Aryl or C ₂₀ And (3) an aryl group. Suitable examples include, but are not limited to: benzene, biphenyl, naphthalene, anthracene, phenanthrene, perylene, triphenylene, and derivatives thereof. It will be appreciated that multiple aryl groups may also be interrupted by short non-aromatic units (e.g. by short non-aromatic units)<10% of atoms other than H, such as C, N or O atoms), such as in particular acenaphthene, fluorene, or 9, 9-diarylfluorene, triarylamine, diaryl ether systems should also be included in the definition of aryl.

The term "heteroaryl" means that on the basis of an aryl group at least one carbon atom is replaced by a non-carbon atom which may be a N atom, an O atom, an S atom, etc. For example, "C ₃ ～C ₁₀ Heteroaryl "refers to a heteroaryl group containing 3 to 10 carbon atoms, which at each occurrence, independently of each other, may be C ₃ Heteroaryl group, C ₄ Heteroaryl group, C ₅ Heteroaryl, C ₆ Heteroaryl group, C ₇ Heteroaryl or C ₈ A heteroaryl group. Suitable examples include, but are not limited to: furan, benzofuran, thiophene, benzothiophenePyrrole, 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, phthalazine, phenanthridine, primadine, quinazoline, and quinazolinone.

Among the technical scheme of this application, through designing molecular structure, provide the polymer that contains azide group that formula I is shown, this polymer has stronger appeal to electrolyte solvent molecule commonly used, adsorbs electrolyte easily, consequently, this polymer can add in anodal active material layer to improve the adsorption affinity of positive pole piece to electrolyte, can effectively promote the ion-conducting capacity of battery, and then promote the circulation performance of battery.

In some embodiments, the value ranges of m and n are: m is more than or equal to 500 and less than or equal to 10000, n is more than or equal to 10 and less than or equal to 10000;

preferably, 1000. Ltoreq. M.ltoreq.10000, 20. Ltoreq. N.ltoreq.5000;

further preferably, 3000. Ltoreq. M.ltoreq.7000, 30. Ltoreq. N.ltoreq.1500;

still more preferably, 4500. Ltoreq. M.ltoreq.6000, 40. Ltoreq. N.ltoreq.200.

The value of m can also be, for example, 4750, 5000, 5250, 5500, 5750; n may also take the value of 60, 80, 100, 120, 140, 160 or 180, for example.

By controlling the number of polymerization units in the molecular structure of the polymer within a proper range, the affinity of the polymer to electrolyte can be effectively improved, and negative effects on other performances of the battery are not caused.

In some embodiments, each occurrence of a is independently selected from-CH ₂ -, -NH-or-O-;

preferably, A is independently selected for each occurrence from-NH-or-O-;

further preferably, A is selected from-O-.

In some embodiments, R ¹ ～R ² Each occurrence is independentlySelected from-H, -D, -OH, -NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, R ¹ ～R ² Each occurrence is independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indolyl or carbazolyl;

further preferably, R ¹ ～R ² Each occurrence is independently selected from-H or methyl.

In some embodiments, R ⁵ Each occurrence is independently selected from-H, -D, -OH, -NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, R ⁵ Each occurrence is independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indolyl or carbazolyl;

further preferably, R ⁵ Each occurrence is independently selected from-H, methyl, ethyl, n-propyl or isopropyl.

In some embodiments, R ³ ～R ⁴ 、R ⁶ ～R ¹¹ Each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ 、-CN、-F、-Cl、-BrUnsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, R ³ ～R ⁴ 、R ⁶ ～R ¹¹ Each occurrence is independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indolyl or carbazolyl;

further preferably, R ³ ～R ⁴ 、R ⁶ ～R ¹¹ Each occurrence is independently selected from-H.

In a second aspect of the present application, there is provided a polymer comprising an electrically conductive carbon material having a structure represented by formula II:

x is independently selected from-C (R) at each occurrence ¹⁷ R ¹⁸ )-、

* Represents a linking site;

R ¹⁷ ～R ²⁸ each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, halogen, unsubstituted or R ²⁹ Substituted C _1～ C ₆ Alkyl, unsubstituted or R ³⁰ Substituted C _1～ C ₆ Alkoxy, unsubstituted or R ³¹ Substituted C _2～ C ₆ Alkenyl, unsubstituted or R ³² Substituted aryl with 6-20 ring atoms, unsubstituted or R ³³ SubstitutionA heteroaryl group having 5 to 20 ring atoms;

R ²⁹ ～R ³³ each occurrence is independently selected from-H, -D, -OH, -NH ₂ 、-NO ₂ 、-CF ₃ -CN, halo, methyl, ethyl, methoxy or phenyl;

represents a conductive carbon material.

The conductive carbon material is introduced into the branched chain in the polymer shown in the formula II, so that when the polymer is added into the positive active material layer, the adsorption capacity of the positive pole piece to the electrolyte can be improved, the ion conduction capacity and the cycle performance of the battery are improved, and the electron conduction capacity of the battery can be effectively improved. When m/n is larger, the affinity to electrolyte is strong, the ion conducting capability of the pole piece is strong, but the electron conducting capability is poorer because n is smaller and the number of connected conductive carbon units is less; on the contrary, when m/n is smaller, the ion conducting capability of the pole piece is improved to a limited extent, but the conducting capability of the pole piece is stronger. Therefore, the battery performance can be improved to the maximum extent only by balancing the ion and electron conducting capabilities of the pole piece and adjusting the m/n value within a proper range.

Preferably, X is, for each occurrence, independently selected from-CH ₂ -or-CH ₂ -CH ₂ -；

Further preferably, X is selected from-CH ₂ -。

In some embodiments, the compound has a structure represented by formula II-0:

In some embodiments, the conductive carbon material comprises one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Preferably, the conductive carbon material is superconducting carbon. The polymer shown in the formula II can be compatible with various conventional conductive carbon materials, and has a wide application prospect.

In a third aspect of the present application, there is provided the use of the azide-containing polymer of one or more of the foregoing embodiments and/or the conductive carbon material-containing polymer of one or more of the foregoing embodiments in the manufacture of a secondary battery.

In a fourth aspect of the present application, a secondary battery is provided, which includes a negative electrode plate, an isolation film, and a positive electrode plate, wherein the isolation film is disposed between the negative electrode plate and the positive electrode plate;

the positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer comprises a positive electrode additive, and the positive electrode additive comprises the polymer containing the azide group in one or more of the embodiments and/or the polymer containing the conductive carbon material in one or more of the embodiments.

In some embodiments, the positive active material layer further includes a positive active material including one or more of a lithium-rich manganese-based positive electrode material, a nickel-cobalt-manganese ternary positive electrode material, a lithium iron phosphate positive electrode material, a lithium cobaltate positive electrode material, a lithium manganate positive electrode material, and a lithium titanate positive electrode material. Preferably, the positive active material is a nickel-cobalt-manganese ternary positive material and/or a lithium iron phosphate positive active material. The performance of the battery can be improved to a greater extent by matching with a proper positive active material.

In some embodiments, the positive electrode additive is present in the positive electrode active material layer in an amount of 1% to 5% by mass;

preferably, the mass percentage of the positive electrode additive in the positive electrode active material layer is 1% to 3%, and more preferably, the mass percentage of the positive electrode additive in the positive electrode active material layer is 2.5%. The dosage of the positive electrode additive is controlled within a proper range, so that the conductive and ion conductive capabilities of the battery can be improved, and meanwhile, the impedance of the battery cannot be increased, and the energy density cannot be reduced.

In some embodiments, the positive electrode additive is coated on the surface of the positive electrode active material. The particle size of the commonly used anode active material is from several micrometers to tens of micrometers, and the anode additive prepared by the method can form nanoscale coating on the surface of the anode active material, so that the electron conductivity and ion conductivity of the battery are effectively improved, and the adverse effect on the activity performance of the anode active material is avoided.

In a fifth aspect of the present application, there is provided a battery module including the secondary battery in one or more of the foregoing embodiments.

In a seventh aspect of the present application, an electric device is provided, which includes one or more of the secondary battery, the battery module, and the battery pack in one or more of the foregoing embodiments.

In an eighth aspect of the present application, there is provided a method for preparing an azide group-containing polymer in one or more of the foregoing embodiments, which includes the steps of:

the azido-containing polymers of formula I can be prepared by conventional synthetic methods known to those skilled in the art, mainly involving some conventional polymerization and coupling reactions, but not limited to one specific synthetic method listed below:

1) Under the condition of 0 ℃, 1.1mol of acryloyl chloride and 1mol of azido alcohol are added under the catalysis of 1mL of triethylamine and react for 4 hours to obtain an intermediate product I-2-1;

2) Weighing 1mol of I-1-2, dissolving in 200mL of tetrahydrofuran, vacuumizing, and continuously introducing N into a three-neck flask ₂ Adding 0.05g of Azobisisobutyronitrile (AIBN) initiator, heating to 70 ℃, stirring for reaction for 12 hours, and pouring the obtained crude product into 0 ℃ of ethyl glacial ether for sedimentation to obtain I-1-1;

3) Weighing 0.1mol of I-1-1, adding 1mol of intermediate product I-2-1, dissolving in 200mL of tetrahydrofuran, vacuumizing, and continuously introducing N into a three-neck flask ₂ 0.05g of azobisisobutyronitrile initiator is added, the mixture is heated to 70 ℃, stirred and reacted for 12 hours, and then the obtained crude product is poured into 0 ℃ of ethyl glacial ether for sedimentation to obtain the additive I (namely the polymer containing the azide group shown in the formula I).

In a ninth aspect of the present application, there is provided a method of preparing a polymer comprising a conductive carbon material in one or more of the foregoing embodiments, comprising the steps of:

performing cycloaddition reaction on the polymer containing the azide group shown in the formula I and the compound shown in the formula II-1 to obtain the polymer containing the azide group shown in the formula II; the conditions of the cycloaddition reaction may be conventional conditions known to those skilled in the art, and a specific synthetic method is listed below, but not limited thereto:

1) Under the condition of 25 ℃, 1.1mol of alkynol and 1mol of SP (superconducting carbon) subjected to surface carboxylation treatment are added under the catalysis of 0.1mol of DCC (dicyclohexylcarbodiimide) and 0.1mol of DMAP (4-dimethylaminopyridine) to react for 8 hours to obtain an intermediate product II-1;

2) Weighing 1mol of the prepared additive I, dissolving the additive I in 200mL of tetrahydrofuran, adding 1.1mol of intermediate product II-1, vacuumizing, and continuously introducing N into a three-neck flask ₂ 0.1mol of CuCl is added, and after stirring reaction at room temperature for 12 hours, the obtained crude product is poured into 0 ℃ of ethyl glacial ether for sedimentation to obtain an additive II (namely the polymer containing the azide group shown in the formula II).

The secondary battery, the battery module, the battery pack, and the electric device according to the present invention will be described below with reference to the drawings as appropriate.

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. In the process of charging and discharging the battery, active ions are embedded and separated back and forth between the positive pole piece and the negative pole piece. The electrolyte plays a role in conducting ions between the positive pole piece and the negative pole piece. The isolating membrane is arranged between the positive pole piece and the negative pole piece, mainly plays a role in preventing the short circuit of the positive pole and the negative pole, and can enable ions to pass through.

Positive pole piece

The positive electrode piece 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 additive (namely the polymer containing azide groups shown in the formula I and/or the polymer containing the conductive carbon material shown in the formula II) of the fourth aspect of the application.

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

In some embodiments, the positive electrode 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 polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a base material of a polymer material (e.g., a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

In some embodiments, the positive active material may employ a positive active material for a battery, which is well known in the art. As an example, the positive electrode active material may include at least one of the following materialsThe method comprises the following steps: 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 positive electrode active material of a battery may be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of the lithium transition metal oxide 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 ₂ O ₄ ) Lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi) _1/3 Co _1/3 Mn _1/3 O ₂ (may also be abbreviated as NCM) ₃₃₃ )、LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (may also be abbreviated as NCM) ₅₂₃ )、LiNi _0.5 Co _0.25 Mn _0.25 O ₂ (may also be abbreviated as NCM) ₂₁₁ )、LiNi _0.6 Co _0.2 Mn _0.2 O ₂ (may also be abbreviated as NCM) ₆₂₂ )、LiNi _0.8 Co _0.1 Mn _0.1 O ₂ (may also be abbreviated as NCM) ₈₁₁ ) Lithium nickel cobalt aluminum oxides (e.g., liNi) _0.85 Co _0.15 Al _0.05 O ₂ ) And modified compounds thereof, and the like. Examples of olivine structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (e.g., liFePO) ₄ (also referred to as LFP for short)), a composite material of lithium iron phosphate and carbon, and lithium manganese phosphate (e.g., liMnPO) ₄ ) At least one of a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

In some embodiments, the positive electrode film layer further optionally includes a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluoroacrylate resin.

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 above-mentioned components for preparing the positive electrode sheet, such as the positive electrode active material, the positive electrode additive provided in the fourth aspect of the present application, the conductive agent, the binder, and any other components in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; and coating the positive electrode slurry on a positive electrode current collector, and drying, cold pressing and the like to obtain the positive electrode piece.

Negative pole piece

The negative pole piece includes the negative pole mass flow body and sets up the negative pole rete on the negative pole mass flow body at least one surface, the negative pole rete includes negative pole active material.

As an example, the negative electrode current collector has two surfaces opposite in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two surfaces opposite to the negative electrode 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 can be used. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a base material of a polymer material (e.g., a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

In some embodiments, the negative active material is the negative active material included in any of the examples herein.

In some embodiments, the anode film layer further optionally includes a binder. The binder may be at least one selected from Styrene Butadiene Rubber (SBR), polyacrylic acid (PAA), sodium Polyacrylate (PAAs), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium Alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

In some embodiments, the negative electrode film layer further optionally includes a conductive agent. The conductive agent may be selected from at least one of 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 further optionally include other additives, such as a thickener (e.g., sodium carboxymethyl cellulose (CMC-Na)), and the like.

In some embodiments, the negative electrode sheet can be prepared by: dispersing the components for preparing the negative electrode plate, such as a negative electrode active material, a conductive agent, a binder and any other components, in a solvent (such as deionized water) to form negative electrode slurry; and coating the negative electrode slurry on a negative electrode current collector, and drying, cold pressing and the like to obtain the negative electrode pole piece.

Electrolyte

The electrolyte plays a role in conducting ions between the positive pole piece and the negative pole piece. The kind of the electrolyte is not particularly limited and may be selected as desired. For example, the electrolyte may be liquid, gel, or all solid.

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

In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium dioxaoxalato borate, lithium difluorodioxaoxalato phosphate, and lithium tetrafluorooxalato phosphate.

In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1, 4-butyrolactone, sulfolane, dimethylsulfone, methylethylsulfone, and diethylsulfone.

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

Isolation film

In some embodiments, the electrode assembly includes a separator between the positive and negative electrode tabs.

In some embodiments, the secondary battery further comprises a separator, wherein the separator is positioned between the positive pole piece and the negative pole piece.

The type of the separator is not particularly limited, and any known separator having a porous structure and good chemical and mechanical stability may be used.

In some embodiments, the material of the isolation 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 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 exterior package. The exterior package may be used to enclose the electrode assembly and electrolyte.

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 outer package of the secondary battery may also be a pouch, such as a pouch-type pouch. The material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.

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

In some embodiments, referring to fig. 2, the overwrap may include a housing 51 and a cover plate 53. The housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose to form an accommodating cavity. The housing 51 has an opening communicating with the accommodating chamber, and a cover plate 53 can be provided to cover the opening to close the accommodating 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. An electrode assembly 52 is enclosed within the receiving cavity. The electrolyte is impregnated into the electrode assembly 52. The number of electrode assemblies 52 contained in the secondary battery 5 may be one or more, and those skilled in the art can select them according to the actual needs.

In some embodiments, the secondary batteries may be assembled into a battery module, and the number of the secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those 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 arranged in series along the longitudinal direction of the battery module 4. Of course, the arrangement may be in any other manner. The plurality of secondary batteries 5 may be further fixed by a fastener.

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

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

Fig. 4 and 5 are a battery pack 1 as an example. Referring to fig. 4 and 5, a battery pack 1 may include a battery case and a plurality of battery modules 4 disposed in the battery case. The battery box comprises an upper box body 2 and a lower box body 3, wherein 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. A plurality of battery modules 4 may be arranged in any manner in the battery box.

In addition, this application still provides a power consumption device, power consumption device includes at least one in secondary battery, battery module or the battery package that this application provided. The secondary battery, the battery module, or the battery pack may be used as a power source of the electric device, and may also be used as an energy storage unit of the electric device. The electric device may include, but is not limited to, a mobile device, an electric vehicle, an electric train, a ship and a satellite, an energy storage system, and the like. The mobile device may be, for example, a mobile phone, a notebook computer, or the like; the electric vehicle may be, for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, or the like, but is not limited thereto.

As the electricity-using device, a secondary battery, a battery module, or a battery pack may be selected according to the use requirement thereof.

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

As another example, the device may be a cell phone, tablet, laptop, etc. The device is generally required to be thin and light, and a secondary battery may be used as a power source.

The present application will be described in further detail with reference to specific examples and comparative examples. Experimental parameters not described in the following specific examples are preferably referred to the guidelines given in the present application, and may be referred to experimental manuals in the art or other experimental methods known in the art, or to experimental conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available. It is understood that the following examples are specific to the particular apparatus and materials used, and in other embodiments, are not limited thereto; the weight of the related components mentioned in the embodiments of the present specification may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the content of the related components is scaled up or down within the scope disclosed in the embodiments of the present specification as long as it is scaled up or down according to the embodiments of the present specification. Specifically, the weight described in the specification of the examples of the present application may be in units of mass known in the chemical and chemical fields, such as μ g, mg, g, and kg.

Example 1

1. Preparation of additive I (i.e. polymer I comprising an azide group):

1) Adding 1.1mol of acryloyl chloride and 1mol of azido ethanol under the catalysis of 1mL of triethylamine at the temperature of 0 ℃, and reacting for 4 hours to obtain an intermediate product A;

2) Weighing 1mol of allyl methyl carbonate, dissolving the allyl methyl carbonate in 200mL of tetrahydrofuran, vacuumizing, and continuously introducing N into a three-neck flask ₂ Adding 0.05g of Azobisisobutyronitrile (AIBN) initiator, heating to 70 ℃, stirring for reaction for 12 hours, and pouring the obtained crude product into 0 ℃ of ethyl glacial ether for sedimentation to obtain a propylene carbonate polymer C;

3) Weighing 0.1mol of propylene carbonate polymer C, adding 1mol of intermediate product A, dissolving in 200mL of tetrahydrofuran, vacuumizing, and continuously introducing N into a three-neck flask ₂ Adding 0.05g of azobisisobutyronitrile initiator, heating to 70 ℃, stirring for reaction for 12 hours, and pouring the obtained crude product into 0 ℃ of ethyl glacial ether for sedimentation to obtain the additive I.

2. Preparation of additive II (i.e. polymer II comprising conductive carbon material):

1) Adding 1.1mol of propargyl alcohol and 1mol of SP (superconducting carbon) subjected to surface carboxylation treatment under the catalysis of 0.1mol of DCC (dicyclohexylcarbodiimide) and 0.1mol of DMAP (4-dimethylaminopyridine) at the temperature of 25 ℃, and reacting for 8 hours to obtain an intermediate product B;

2) Weighing 1mol of the prepared additive I, dissolving the additive I in 200mL of tetrahydrofuran, adding 1.1mol of the intermediate product B, vacuumizing, and continuously introducing N into a three-neck flask ₂ Adding 0.1mol of CuCl, stirring and reacting for 12h at room temperatureAnd pouring the obtained crude product into glacial ethyl ether at the temperature of 0 ℃ for sedimentation to obtain the additive II.

3. Preparing a lithium ion battery:

1) Preparing a positive pole piece: uniformly mixing the lithium-rich manganese-based positive electrode material, the prepared additive II and a binding agent polyvinylidene fluoride (PVDF) according to a mass ratio of 96.5;

2) Preparing a negative pole piece: after dry-mixing graphite and SP (superconducting carbon) according to a mass ratio of 97, adding deionized water, adjusting the solid content to 45% -55%, uniformly stirring to obtain a negative electrode slurry, and preparing a negative electrode plate by coating, drying, cold-pressing and slitting;

3) Winding the pole pieces and the diaphragms prepared in the steps 1) and 2) into a battery cell, packaging the battery cell into a dry battery cell by using an aluminum plastic film, and carrying out processes such as liquid injection, formation, aging and the like to prepare the lithium ion battery.

Example 2

Essentially in accordance with example 1, except that in the preparation of additive I, 0.1g of AIBN was used in step 2) and 0.02g of AIBN was used in step 3).

Example 3

Essentially as in example 1, except that in the preparation of additive I, the amount of AIBN used in step 2) was 0.15g and the amount of AIBN used in step 3) was 0.02g.

Example 4

Essentially in accordance with example 1, with the difference that in the preparation of additive I allyl methyl carbonate is replaced in step 2) with an equivalent amount of diallyl carbonate.

Example 5

In substantial agreement with example 1, except that in the preparation of additive I, acryloyl chloride was replaced in step 1) with equal amounts of methacryloyl chloride.

Example 6

In substantial agreement with example 1, except that in the preparation of the additive II, the surface-carboxylated SP (superconducting carbon) was replaced with the surface-carboxylated carbon black in an amount equivalent to that of the additive in step 1).

Example 7

In substantial agreement with example 1, the difference is that in the preparation of the additive II, SP (superconducting carbon) subjected to surface carboxylation treatment is replaced with carbon nanotubes subjected to surface carboxylation treatment in an amount equivalent to that of the above-mentioned substance in step 1).

Example 8

Basically the same as example 1, except that in the preparation of the lithium ion battery, the lithium-rich manganese-based positive electrode material is replaced by the nickel-cobalt-manganese ternary positive electrode material with equal mass in step 1).

Example 9

Basically the same as example 1, except that in the preparation of the lithium ion battery, the lithium-rich manganese-based positive electrode material is replaced by the lithium iron phosphate positive electrode material with the same mass in step 1).

Example 10

Basically the same as example 1, except that in the preparation of the lithium ion battery, the lithium-rich manganese-based cathode material is replaced by the lithium manganate cathode material with equal quality in step 1).

Example 11

In substantial agreement with example 1, except that in the preparation of the lithium ion battery, additive II was replaced with an equal mass of a combination of additives i and SP in step 1), i.e. the positive electrode formulation was as follows:

lithium-rich manganese-based positive electrode material: additive I prepared above: SP: adhesive polyvinylidene fluoride (PVDF) mass ratio of 96

Example 12

In substantial agreement with example 1, except that half the mass of additive II was replaced with additive I in step 1) in the preparation of the lithium ion battery, i.e., the positive electrode active material formulation was as follows:

lithium-rich manganese-based positive electrode material: additive I prepared above: additive II prepared above: the mass ratio of the adhesive polyvinylidene fluoride (PVDF) is 96.

Comparative example 1

1) Preparing a positive pole piece: uniformly mixing a lithium-manganese-based positive electrode material, SP (superconducting carbon) subjected to surface carboxylation treatment and a polyvinylidene fluoride (PVDF) binder in a mass ratio of (2.5);

Comparative example 2

In substantial agreement with comparative example 1, except that in the preparation of additive II, the surface-carboxylated SP (superconducting carbon) was replaced with the surface-carboxylated carbon black in an amount equivalent to that in step 1).

Comparative example 3

In substantial agreement with comparative example 1, except that in the preparation of additive II, SP (superconducting carbon) surface-carboxylated was replaced with equal amounts of carbon nanotubes surface-carboxylated in step 1).

Comparative example 4

Basically consistent with the comparative example 1, the difference is that in the preparation of the lithium ion battery, the lithium-rich manganese-based positive electrode material is replaced by the nickel-cobalt-manganese ternary positive electrode material with the same mass in the step 1).

Comparative example 5

Basically consistent with the comparative example 1, the difference is that in the preparation of the lithium ion battery, the lithium-rich manganese-based positive electrode material is replaced by the lithium iron phosphate positive electrode material with equal mass in the step 1).

Comparative example 6

Basically consistent with comparative example 1, the difference is that in the preparation of the lithium ion battery, the lithium-rich manganese-based positive electrode material is replaced by the lithium manganate positive electrode material with equal quality in step 1).

Comparative example 7

In substantial agreement with example 1, except that the proportion of additive II in step 1) was 10% in the preparation of the lithium ion battery.

Characterization test:

the pole pieces or lithium ion batteries prepared in the previous examples and comparative examples were subjected to the following characterization tests:

1. pole piece testing

1. Pole piece electronic conductivity test

According to the standard GB/T32055-2015, a daily BT3563S resistance instrument is adopted, the negative pole pieces of the embodiments and the comparative examples are taken, the thickness d of the pole pieces is measured by a micrometer screw, then a sample is placed on a resistance instrument test bench for testing, the area of the tested pole pieces is 1540.25mm2, the test pressure is not less than 0.4T, the time interval is 10S, the resistance R is measured, and the electronic conductivity rho S is calculated by a formula: ρ s = 1/(R × d).

2. Pole piece ionic conductivity test

Taking the negative pole pieces of the embodiments and the comparative examples, assembling the negative pole pieces into a symmetrical battery, and carrying out an alternating current impedance test at the temperature of 25 ℃, wherein the test instrument comprises the following components: and in the VMP3 electrochemical workstation, the number of frequency points is 73, the number of single-frequency point tests is 2, the test frequency range is 500kHz-30mHz, and the measured data are subjected to fitting treatment and calculation to obtain the ionic conductivity rho l of the pole piece.

2. Battery performance testing

1. Battery low temperature capacity retention rate test

The cell was charged at 25 ℃ at a constant current of 1/3C to 4.3V, further charged at a constant voltage of 4.3V to a current of 0.05C, and further discharged at 1/3C to a voltage of 2.8V, and the resulting capacity was designated as initial capacity C0. At 25 ℃, charging the battery to 4.3V at a constant current of 1/3C, then charging to 0.05C at a constant voltage of 4.3V, then transferring the battery to a low-temperature box at-20 ℃, standing for 2h until the battery core reaches thermal equilibrium, then discharging to 2.0V at 1/3C, wherein the obtained capacity is marked as D1, and the low-temperature capacity retention ratio is as follows: r = D1/D0 × 100%.

2. Battery direct current impedance (DCR) testing

At 25 ℃, the cell was charged to 4.3V at a constant current of 1/3C, then charged to a current of 0.05C at a constant voltage of 4.3V, and after standing for 5min, the voltage V1 was recorded. And then discharging for 30s at 1/3C, and recording the voltage V2, so that the internal resistance DCR of the battery is = (V2-V1)/(1/3C).

3. Battery cycle performance test

1.25 ℃ cycle: charging the battery at 25 deg.C with constant current of 1/3C to voltage of 4.3V, charging at constant voltage of 4.3V to current of 0.05C, standing for 5min, discharging at 1/3C to voltage of 2.8V, and recording the obtained capacity as initial capacity C ₀ . Repeating the above steps for the same cell, and simultaneously recording the discharge capacity C of the cell after the nth cycle _n The capacity retention rate of the battery after each cycle is P _n ＝C _n The discharge capacity retention rates after 1000 cycles of the examples and the comparative examples were measured, respectively, at 0X 100%/C.

2.45 ℃ cycle: charging the battery at 25 deg.C with constant current of 1/3C to voltage of 4.3V, charging at constant voltage of 4.3V to current of 0.05C, standing for 5min, discharging at 1/3C to voltage of 2.8V, and recording the obtained capacity as initial capacity C ₀ . And then placing the battery in a high-low temperature box at 45 ℃, performing cyclic charge and discharge after heat balance, wherein the flow is consistent with the flow of measuring capacity at 25 ℃. Transferring to 25 ℃ environment after 500 cycles of circulation, carrying out one-time charging and discharging process after heat balance, and recording the discharge capacity C after 500 cycles of circulation ₅₀₀ Calculating the capacity retention rate: p ₅₀₀ ＝C ₅₀₀ /C ₀ ×100％

TABLE 1

Description of the drawings: all of the substituents not shown in Table 1 are-H.

* In example 11, additive II was not included, and the conductive carbon was directly physically blended with additive I for use.

TABLE 2

As can be seen from table 2, after the positive electrode additive prepared by the method is added into a battery, the ionic conductivity and the electronic conductivity of the battery are high, DCR is small, the capacity retention rate is good at-20 ℃, 25 ℃ and 45 ℃, the electrical property is excellent, and the defects of poor ionic conductivity and electronic conductivity and limited cycle performance of a positive electrode material in the conventional technology are effectively overcome. It is understood from comparative examples 1 to 3 that the electron conductivity is slightly improved as the m/n is decreased, but the ion conductivity is considerably decreased, and thus the battery performance is also decreased, but the battery performance is maintained at a preferable level. It is understood that similar improvement effects can be obtained by appropriately expanding the additive structure in comparative examples 1,4 and 5. Comparative examples 1, 6 and 7 show that the additive of the present application can be applied to various conductive carbons, and comparative examples 1, 8, 9 and 10 show that the additive of the present application can be applied to various positive electrode active materials, and the application range is wide. In example 11, the battery performance can also be improved by physically blending the additive I with conductive carbon, but the effect is not as good as that of example 1; in example 12, the performance was also reduced by changing half of additive II to additive I, because the amount of conductive carbon used was reduced.

In comparative example 1, compared to example 1, only superconducting carbon was added without additives, and although the mass percentage of superconducting carbon in the positive electrode active material layer was 2 times that of example 1, the electron conductivity was still inferior to that of example 1, and the ion conductivity was more seriously decreased, and accordingly, DCR was increased and the cycle performance at each temperature was much deteriorated. In comparative examples 2 to 6, the same shows similar downward tendency by replacing different types of conductive agents or positive electrode active materials. In comparative example 7, the additive II is too much, and the additive forms a coating on the surface of the positive active material, so that too much usage does not increase the ionic conductivity and the electronic conductivity, but causes a large resistance of the electrode sheet, and particularly when the conductive carbon connected to the electrode sheet is less, the polarization of the battery is large, the low-temperature capacity retention rate is low, and the overall capacity of the battery is reduced, and the energy density is reduced.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the patent is subject to the appended claims, and the description and the drawings can be used for explaining the contents of the claims.

Claims

1. A polymer comprising an azide group having the structure of formula I:

m and n are positive integers and m/n =1 to 100; preferably, m/n =50 to 100.

2. The polymer according to claim 1, wherein m and n respectively have the following value ranges: m is more than or equal to 500 and less than or equal to 10000, n is more than or equal to 10 and less than or equal to 10000;

preferably, 1000. Ltoreq. M.ltoreq.10000, 20. Ltoreq. N.ltoreq.5000;

further preferably, 3000. Ltoreq. M.ltoreq.7000, 30. Ltoreq. N.ltoreq.1500;

still more preferably, 4500. Ltoreq. M.ltoreq.6000, 40. Ltoreq. N.ltoreq.200.

3. The polymer of claim 1, wherein each occurrence of a is independently selected from-CH ₂ -, -NH-or-O-;

further preferably, said a is selected from-O-.

4. The polymer of claim 1, wherein R is ¹ ～R ² Each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, said R is ¹ ～R ² Each occurrence is independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indoleA group or a carbazolyl group;

5. The polymer of claim 1, wherein R is ⁵ Each occurrence is independently selected from-H, -D, -OH, -NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

6. The polymer of claim 1, wherein R is ³ ～R ⁴ 、R ⁶ ～R ¹¹ Each occurrence is independently selected from-H, -D, -OH and-NH ₂ 、-NO ₂ 、-CF ₃ -CN, -F, -Cl, -Br, unsubstituted C _1～ C ₄ Alkyl, unsubstituted C _1～ C ₄ Alkoxy, unsubstituted C _2～ C ₄ An alkenyl group, an unsubstituted aryl group having 6 to 10 ring atoms, or an unsubstituted heteroaryl group having 5 to 10 ring atoms;

preferably, said R is ³ ～R ⁴ 、R ⁶ ～R ¹¹ In each of the occurrences of the first and second images, each independently selected from-H, -Br, methyl, ethyl, n-propyl, isopropyl n-butyl, isobutyl, tert-butyl, methoxy, ethoxy,Vinyl, propenyl, allyl, phenyl, naphthyl, phenanthryl, thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, indolyl or carbazolyl;

7. A polymer comprising an electrically conductive carbon material having a structure represented by formula II:

x is independently selected from-C (R) at each occurrence ¹⁷ R ¹⁸ )-、

* Represents a linking site;

R ¹⁷ ～R ²⁸ each occurrence is independently selected from-H, -D, -OH, -NH ₂ 、-NO ₂ 、-CF ₃ -CN, halogen, unsubstituted or R ²⁹ Substituted C _1～ C ₆ Alkyl, unsubstituted or R ³⁰ Substituted C _1～ C ₆ Alkoxy, unsubstituted or R ³¹ Substituted C _2～ C ₆ Alkenyl, unsubstituted or R ³² Substituted aryl with 6-20 ring atoms, unsubstituted or R ³³ A substituted heteroaryl group having 5 to 20 ring atoms;

represents a conductive carbon material.

8. The polymer of claim 7, wherein each occurrence of X is independently selected from-CH ₂ -、-CH ₂ -CH ₂ -or-CH ₂ -CH ₂ -CH ₂ -；

Further preferably, X is selected from-CH ₂ -。

9. The polymer of claim 7, having a structure according to formula II-0:

10. The polymer of any one of claims 7 to 9, wherein the conductive carbon material comprises one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

11. Use of a polymer comprising an azide group according to any one of claims 1 to 6 and/or a polymer comprising an electrically conductive carbon material according to any one of claims 7 to 10 for the preparation of a secondary battery.

12. A secondary battery is characterized by comprising a negative pole piece, an isolation film and a positive pole piece, wherein the isolation film is arranged between the negative pole piece and the positive pole piece;

wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, the positive electrode active material layer comprises a positive electrode additive, and the positive electrode additive comprises the polymer containing azide groups according to any one of claims 1 to 6 and/or the polymer containing conductive carbon materials according to any one of claims 7 to 10.

13. The secondary battery of claim 12, wherein the positive active material layer further comprises a positive active material comprising one or more of a lithium rich manganese based positive electrode material, a nickel cobalt manganese ternary positive electrode material, a lithium iron phosphate positive electrode material, a lithium cobalt oxide positive electrode material, a lithium manganese oxide positive electrode material, and a lithium titanate positive electrode material.

14. The secondary battery according to claim 12 or 13, wherein the positive electrode additive is contained in the positive electrode active material layer in an amount of 1 to 5% by mass;

preferably, the mass percentage of the positive electrode additive in the positive electrode active material layer is 1-3%.

15. The secondary battery according to claim 12 or 13, wherein the positive electrode additive is coated on the surface of the positive electrode active material.

16. A battery module comprising the secondary battery according to any one of claims 12 to 15.

17. A battery pack comprising the battery module according to claim 16.

18. An electric device comprising one or more of the secondary battery according to any one of claims 12 to 15, the battery module according to claim 16, and the battery pack according to claim 17.

19. The method for producing the azide-containing polymer according to any one of claims 1 to 6, comprising the steps of:

20. the method for producing a polymer comprising an electrically conductive carbon material according to any one of claims 7 to 10, comprising the steps of: