CN110739458A

CN110739458A - conductive polymer alkali metal salt with heat-sensitive characteristic and preparation method and application thereof

Info

Publication number: CN110739458A
Application number: CN201810790006.1A
Authority: CN
Inventors: 马强; 李阳兴; 秦德君
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-07-18
Filing date: 2018-07-18
Publication date: 2020-01-31
Anticipated expiration: 2038-07-18
Also published as: CN110739458B

Abstract

The embodiment of the invention provides conductive polymer alkali metal salts with thermal sensitivity, which comprise conductive polymer repeating units and substituted imine alkali metal salts grafted on the conductive polymer repeating units, wherein each conductive polymer repeating unit comprises a five-membered unsaturated heterocyclic structure, each substituted imine alkali metal salt comprises or more of substituted imide alkali metal salts and substituted sulfonyl imide alkali metal salts, and the substituted imine alkali metal salts form an N-C bond with a C atom in the five-membered unsaturated heterocyclic structure through an N atom.

Description

conductive polymer alkali metal salt with heat-sensitive characteristic and preparation method and application thereof

Technical Field

The invention relates to the technical field of secondary batteries, in particular to conductive polymer alkali metal salts with heat-sensitive characteristics, and a preparation method and application thereof.

Background

With the development of scientific technology, electronic consumer products (mobile phones and digital cameras) and professional electronic devices are gradually miniaturized and portable, and the use functions are continuously expanded, so that higher requirements are provided for the energy density of energy storage devices (such as batteries), however, the safety problem of high-energy density devices needs to be solved urgently.

Aiming at the safety problem of the battery caused by thermal runaway, the currently mainstream strategies include three aspects, namely 1) developing a flame-retardant electrolyte, wherein although the flame-retardant electrolyte can reduce the combustion failure rate of the battery to degree, the existing flame-retardant electrolyte has negative effects on the electrochemical performance of the battery, 2) developing a coating diaphragm, wherein the heat resistance of the diaphragm can be improved by adopting the coating diaphragm, the safety performance of the battery is improved at degree, but the use of the coating diaphragm can bring contact problems and can not meet the requirements of the safety of the battery, and 3) developing a thermosensitive material, wherein the thermosensitive material refers to a material which causes chemical or physical change by heat energy, and the resistance of the material is greatly influenced by temperature.

At present, thermal sensitive materials mainly include three major types, namely inorganic oxide materials (such as strontium-doped barium titanate, lead-doped barium titanate and the like), conductive agent and polymer mixed materials (such as carbon black and polyoxyethylene mixed materials) and conductive polymer materials (such as polythiophene compounds), wherein the conductive polymer materials are generally composed of a polymer chain structure and -valent anions or cations which are not bonded with the chain, so that the conductive polymer not only has metal characteristics (such as high conductivity) and semiconductor characteristics caused by doping, but also has the characteristics of diversified molecular design structure, processability, light specific gravity and the like.

Disclosure of Invention

In view of this, according to , alkali metal salts of conductive polymers with thermal sensitivity are provided, which have excellent thermal sensitivity, conductivity and ion conductivity, and can be applied to secondary batteries to effectively improve the safety and electrochemical performance of the batteries, so as to solve the problem that the existing heat-sensitive materials of conductive polymers can improve the safety of the batteries by , but do not have ion conductivity, which causes the reduction of the cycle, rate and low temperature performance of the batteries.

Specifically, according to the aspect of the embodiments of the present invention, kinds of conductive polymer alkali metal salts with heat-sensitive characteristics are provided, including a conductive polymer repeating unit and a substituted imine alkali metal salt grafted on the conductive polymer repeating unit, the conductive polymer repeating unit includes a five-membered unsaturated heterocyclic structure, the substituted imine alkali metal salt includes or more of a substituted imide alkali metal salt and a substituted sulfonyl imide alkali metal salt, and the substituted imine alkali metal salt forms an N-C bond with a C atom in the five-membered unsaturated heterocyclic structure through an N atom.

Wherein the chemical expression of the substituted imide alkali metal salt is-N (M)⁺)-C(＝O)-Z₁Wherein M is Li, Na, K, Rb or Cs, Z₁ kinds selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy.

Wherein the chemical expression of the substituted sulfimide alkali metal salt is-N (M)⁺)-S(＝O)₂-Z₂Wherein M is Li, Na, K, Rb or Cs, Z₂Selected from alkyl, haloalkyl, alkoxy, haloalkoxyAny of alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy, and haloaryloxy.

The conductive polymer alkali metal salt comprises repeating units of the conductive polymer.

The conductive polymer repeating unit comprises or more five-membered unsaturated heterocyclic structures, and specifically, the five-membered unsaturated heterocyclic structures comprise at least of thiophene, pyrrole and furan.

The conductive polymer repeating unit comprises five-membered unsaturated heterocyclic structures, and the groups at the 3-position and the 4-position of the five-membered unsaturated heterocyclic structures are R respectively₁And R₂Said R is₁And R₂Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₁And R₂At least of (a) are the substituted imine alkali metal salt.

The conductive polymer repeating unit comprises a plurality of five-membered unsaturated heterocyclic structures, at least groups in all groups at the 3-position and the 4-position of the five-membered unsaturated heterocyclic structures are the substituted imine alkali metal salt, and the rest groups are respectively selected from any groups of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, halogenated alkyl, alkoxy, halogenated alkoxy, alkenyl, halogenated alkenyl, alkenyloxy, halogenated alkenyloxy, aryl, halogenated aryl, aryloxy and halogenated aryloxy.

Z is₁Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20.

Z is₂Wherein the alkyl group, the haloalkyl group, the alkoxy group, and the haloalkoxy group have 1 to 20 carbon atoms, and the alkenyl group, the haloalkenyl group, and the,The carbon atoms of the alkenyloxy and the halogenated alkenyloxy are 2-20, and the carbon atoms of the aryl, the halogenated aryl, the aryloxy and the halogenated aryloxy are 6-20.

The R is₁And R₂Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20.

The conductive polymer alkali metal salt with thermal sensitivity provided by the embodiment of the invention is formed by grafting the substituted imine alkali metal salt onto the repeating unit containing the five-membered unsaturated heterocyclic structure, and the conductive polymer material grafted by the substituted imine alkali metal salt has excellent thermal sensitivity, conductive ion capacity and ion conduction capacity, and can be applied to a secondary battery, thereby not only effectively improving the safety of the battery, but also improving the electrochemical performance of the battery, and solving the problem that the existing conductive polymer thermal sensitive material can improve the safety of the battery at a fixed range of , but also can cause the reduction of the performances of the battery such as cycle, multiplying power, low temperature and the like due to the lack of ion conduction.

Accordingly, the second aspect of the embodiments of the present invention provides methods for preparing alkali metal salts of conductive polymers with heat-sensitive characteristics, comprising the following steps:

reacting a polymer monomer at-40-100 ℃ for 6-48 hours in the presence of an initiator and a solvent, and polymerizing the polymer monomer to obtain a conductive polymer alkali metal salt with heat-sensitive characteristics, wherein the polymer monomer comprises a five-membered unsaturated heterocyclic structure and a substituted imine alkali metal salt positioned on the five-membered unsaturated heterocyclic structure, the conductive polymer alkali metal salt comprises a conductive polymer repeating unit and a substituted imine alkali metal salt grafted on the conductive polymer repeating unit, the conductive polymer repeating unit comprises a five-membered unsaturated heterocyclic structure, the substituted imine alkali metal salt comprises or more of a substituted imide alkali metal salt and a substituted sulfimide alkali metal salt, and the substituted imine alkali metal salt forms an N-C bond with a C atom in the five-membered unsaturated heterocyclic structure through an N atom.

Wherein the polymer monomer is prepared by adopting the following steps:

reacting a halogen-substituted five-membered unsaturated heterocyclic compound with a substituted amine compound in the presence of an acid-binding agent and a solvent at 0-60 ℃ for 6-48 hours to obtain an amine salt, wherein the substituted amine compound comprises or more of substituted amide compounds and substituted sulfonamide compounds;

under the protection of inert gas, reacting the amine salt with anhydrous alkali carbonate at 0-30 ℃ for 2-24 hours to obtain alkali metal salt, and obtaining the polymer monomer.

Specifically, the chemical expression of the substituted amide compound is Z₁-C(＝O)-NH₂The chemical expression of the substituted sulfonamide compound is Z₂-S(＝O)₂-NH₂Z is the same as₁And Z₂ kinds selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy.

The groups at the 3-position and the 4-position in the halogen substituted five-membered unsaturated heterocyclic compound are respectively R₃And R₄Said R is₃And R₄Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₃And R₄At least is fluorine, chlorine, bromine or iodine.

The initiator comprises or more of Azobisisobutyronitrile (AIBN), dibenzoyl peroxide (BPO), potassium persulfate, hydrogen peroxide-ferrous chloride and anhydrous ferric chloride.

The molar ratio of the polymer monomer to the initiator is 1: 0.1-8.

The molar ratio of the halogen substituted five-membered unsaturated heterocyclic compound to the acid-binding agent is 1: 1-10; the molar ratio of the halogen substituted five-membered unsaturated heterocyclic compound to the substituted amine compound is 1: 1-8; the molar ratio of the amine salt to the anhydrous alkali carbonate is 1: 1-10.

The preparation method provided by the second aspect of the embodiment of the invention has simple process and is easy to operate.

In the third aspect of the embodiments of the present invention, composite current collectors are provided, including a current collector body and a thermosensitive material layer disposed on a side surface or two side surfaces of the current collector body , where the thermosensitive material layer includes the conductive polymer alkali metal salt with thermosensitive property according to the aspect of the present invention.

Wherein the heat-sensitive material layer further comprises a binder, and the conductive polymer alkali metal salt with heat-sensitive property is fixed in the heat-sensitive material layer through the binder.

In the thermosensitive material layer, the mass ratio of the conductive polymer alkali metal salt with thermosensitive property to the binder is 1-100: 1.

The thickness of the thermosensitive material layer is 0.01-10 μm.

The embodiment of the present invention further provides electrode materials, which include an electrode active material and a coating layer disposed on the surface of the electrode active material, where the coating layer includes the conductive polymer alkali metal salt with heat-sensitive characteristics according to embodiment of the present invention, and the electrode active material is a positive electrode active material or a negative electrode active material.

Wherein the thickness of the coating layer is 1nm-10 μm.

The embodiment of the invention also provides electrode sheets, which comprise a current collector and an electrode active material layer arranged on the current collector, wherein the electrode active material layer comprises the conducting polymer alkali metal salt with the heat-sensitive property, which is described in the embodiment of the invention, and the electrode sheet is a positive electrode sheet or a negative electrode sheet.

The embodiment of the invention also provides composite diaphragms, which comprise a diaphragm body and heat-sensitive material layers arranged on the side surface or two side surfaces of the diaphragm body , wherein the heat-sensitive material layers comprise the conductive polymer alkali metal salt with heat-sensitive property of the aspect of the invention.

Accordingly, the embodiment of the invention also provides secondary batteries, which comprise a positive electrode, a negative electrode, a separator and an electrolyte, wherein the separator and the electrolyte are arranged between the positive electrode and the negative electrode, and the positive electrode, the negative electrode and/or the separator comprise the conducting polymer alkali metal salt with the heat-sensitive property, which is disclosed by the embodiment of the invention.

By implementing the embodiment of the invention, the safety performance and the electrochemical performance of the secondary battery are greatly improved, the safety problem of the secondary battery caused by thermal runaway in the prior art is solved, and the problem of the electrochemical performance reduction of the battery caused by the introduction of the conventional conductive polymer heat-sensitive material is solved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present invention, the drawings required to be used in the embodiments or the background art of the present invention will be described below.

Fig. 1 is a schematic structural view of a composite current collector in an embodiment of the present invention;

fig. 2 is a schematic structural view of another embodiment of the composite current collector of the present invention;

FIG. 3 is a schematic structural diagram of an electrode material in an embodiment of the present invention;

FIG. 4 is a schematic structural view of an electrode sheet in an embodiment of the invention;

FIG. 5 is a schematic view of an electrode sheet according to another embodiment of the present invention;

FIG. 6 is a schematic representation of the structure of a composite diaphragm in an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a composite diaphragm in another embodiment of the invention.

Detailed Description

The embodiments of the present invention will be described below with reference to the drawings.

With the continuous development of scientific technology, the market demand for high energy density secondary batteries is increasing, and the safety problem of the secondary batteries caused by thermal runaway is also aggravated by the high heat generated by the high energy density, and in order to prevent the thermal runaway, a heat-sensitive material (such as a conductive polymer) with heat-sensitive characteristics is added into the batteries, however, although the existing heat-sensitive material of the conductive polymer can improve the safety of the batteries by , the poor ion transmission performance of the heat-sensitive material can cause the reduction of the performances of the batteries, such as cycle, rate and low temperature, etc. therefore, heat-sensitive materials are needed to be provided, and the safety of the batteries can be improved, and the batteries can have good electrochemical performance.

Based on the situation, the embodiment of the invention provides conductive polymer alkali metal salts with heat-sensitive characteristics, which comprise conductive polymer repeating units and substituted imine alkali metal salts grafted on the conductive polymer repeating units, wherein the conductive polymer repeating units comprise five-membered unsaturated heterocyclic structures, the substituted imine alkali metal salts comprise or more of substituted imide alkali metal salts and substituted sulfonyl imide alkali metal salts, and the substituted imine alkali metal salts form N-C bonds with C atoms in the five-membered unsaturated heterocyclic structures through N atoms.

The conducting polymer alkali metal salt with the heat-sensitive characteristic provided by the embodiment of the invention has excellent heat-sensitive characteristic, electron conductivity and ion conductivity, and can be applied to a secondary battery, so that the safety performance and electrochemical performance of the battery can be effectively improved.

In an embodiment of the invention, the substituted acyl groupThe chemical expression of the imine alkali metal salt is-N (M)⁺)-C(＝O)-Z₁Wherein M is Li, Na, K, Rb or Cs, Z₁ are any members selected from the group consisting of alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy, and haloaryloxy₁Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20. In particular, Z is₁May be but is not limited to-CF₃，-CF₂CF₃，-CF₂CF₂CF₂CF₃，-CF₂CF₂CF₂H，-CH₂CF₃And the like.

In an embodiment of the present invention, the chemical expression of the substituted sulfonimide alkali metal salt is-N (M)⁺)-S(＝O)₂-Z₂Wherein M is Li, Na, K, Rb or Cs, Z₂ are any members selected from the group consisting of alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy, and haloaryloxy₂Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20. In particular, Z is₂May be but is not limited to-CF₃，-CF₂CF₃，-CF₂CF₂CF₂CF₃，-CF₂CF₂CF₂H，-CH₂CF₃And the like.

In an embodiment of the present invention, said alkali metal salt of a conducting polymer comprises repeating units of one or more of said conducting polymers.

In an embodiment of the present invention, the five-membered unsaturated heterocyclic structure includes at least kinds of thiophene, pyrrole, and furan.

When the conductive polymer repeating unit comprises five-membered unsaturated heterocyclic structures, at least of groups at positions 3 and 4 of the five-membered unsaturated heterocyclic structures are the substituted imine alkali metal salt, and of the groups are any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy groups, when the conductive polymer repeating unit comprises a plurality of five-membered unsaturated heterocyclic structures, at least of the groups are the substituted imine alkali metal salt, and the rest of the groups are respectively selected from any 25 of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryloxy and haloaryloxy groups.

In a specific embodiment of of the present invention, the conductive polymer alkali metal salt comprises conductive polymer repeating units, and the conductive polymer repeating units comprise five-membered unsaturated heterocyclic structures, and the chemical structural formula of the conductive polymer repeating units can be represented by formula (1):

wherein X is NH, O or S, n is an integer greater than 1, R₁And R₂Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₁And R₂In at least is the substituted imine alkali metal salt.

In another embodiment of the present invention, the conductive polymer alkali metal salt comprises conductive polymer repeating units, wherein the conductive polymer repeating units comprise two five-membered unsaturated heterocyclic structures, and the chemical structure thereof can be represented by formula (2):

in the structure represented by the formula (2), according to an embodiment of the present invention, X represents₁、X₂Are independently selected from NH, O or S, and X₁、X₂Different, n is an integer greater than 1, R₅、R₆、R₇And R₈Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₅、R₆、R₇And R₈At least of (a) are the substituted imine alkali metal salt.

In another mode for carrying out the invention for the structure represented by formula (2), X is₁、X₂Are independently selected from NH, O or S, and X₁、X₂N is an integer greater than 1, and X is₁In the five-membered heterocycle₅、R₆And said X₂In the five-membered heterocycle₇、R₈At least are different, R₅、R₆、R₇And R₈Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₅、R₆、R₇And R₈At least of (a) are the substituted imine alkali metal salt.

By analogy, in other embodiments of the present invention, the conductive polymer repeating unit may also include three or more five-membered unsaturated heterocyclic structures with different structures.

In another embodiment of the present invention, the conductive polymer alkali metal salt comprises two conductive polymer repeating units, wherein the conductive polymer repeating unit comprises five-membered unsaturated heterocyclic structures, and the chemical structure thereof can be represented by formula (3):

in the structure represented by the formula (3), according to an embodiment of the present invention, X represents₁、X₂Are independently selected from NH, O or S, and X₁、X₂Different from each other, n₁、n₂Is an integer greater than 1, R₁And R₂Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₁And R₂At least of (a) are the substituted imine alkali metal salt.

In another mode for carrying out the invention for the structure represented by formula (3), X represents₁、X₂Are independently selected from NH, O or S, and X₁、X₂Same, n₁、n₂Is an integer greater than 1, R₁And R₂Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₁And R₂At least is the substituted imine alkali metal salt, and X is₁In the five-membered heterocycle₁、R₂And said X₂R in the repeating unit₁、R₂At least are different.

In this way, in other embodiments of the present invention, the conductive polymer alkali metal salt may also include three or more conductive polymer repeating units with different structures.

In an embodiment of the present invention, the above-mentioned alkyl group, haloalkyl group, alkoxy group, and haloalkoxy group have 1 to 20 carbon atoms, the alkenyl group, haloalkenyl group, alkenyloxy group, and haloalkenyloxy group have 2 to 20 carbon atoms, and the aryl group, haloaryl group, aryloxy group, and haloaryloxy group have 6 to 20 carbon atoms. The alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy may be linear or branched. The halogen in the halogenated alkyl, the halogenated alkoxy, the halogenated alkenyl, the halogenated alkenyloxy, the halogenated aryl and the halogenated aryloxy comprises fluorine, chlorine, bromine and iodine, and the halogen is perhalogenated or partially halogenated.

Specifically, in the embodiment of the present invention, the structural formula of the conductive polymer material may be as shown in (a) to (P):

the conductive polymer alkali metal salt with the thermal sensitivity provided by the embodiment of the invention has excellent thermal sensitivity, excellent conductive ion capacity and excellent ion conductivity, and can be applied to a secondary battery, so that the safety and electrochemical performance of the battery can be effectively improved, the battery is prevented from burning and explosion due to thermal runaway, and the battery has good rate capability.

Correspondingly, the embodiment of the invention also provides a preparation method of conductive polymer alkali metal salts with heat-sensitive characteristics, which comprises the following steps:

reacting a polymer monomer at-40-100 ℃ for 6-48 hours in the presence of an anhydrous initiator and a solvent, and polymerizing the polymer monomer to obtain a conductive polymer alkali metal salt with heat-sensitive characteristics, wherein the polymer monomer comprises a five-membered unsaturated heterocyclic structure and a substituted imine alkali metal salt positioned on the five-membered unsaturated heterocyclic structure, the conductive polymer alkali metal salt comprises a conductive polymer repeating unit and a substituted imine alkali metal salt grafted on the conductive polymer repeating unit, the conductive polymer repeating unit comprises a five-membered unsaturated heterocyclic structure, the substituted imine alkali metal salt comprises or more of a substituted imide alkali metal salt and a substituted sulfimide alkali metal salt, and the substituted imine alkali metal salt forms an N-C bond with a C atom in the five-membered unsaturated heterocyclic structure through an N atom.

The alkali metal salt of the conductive polymer prepared by the above preparation method in the embodiment of the present invention is as described in the previous part of the embodiment of the present invention, and is not described herein again.

In the embodiment of the invention, the structural formula of the polymer monomer is shown as a formula (4),

wherein X is NH, O or S, R₁And R₂Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₁And R₂At least is a substituted imine alkali metal salt in one embodiment of the invention, R is₁And R₂Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20.

In one embodiment of the invention, the substituted imide base is goldThe chemical expression of the generic salt is-N (M)⁺)-C(＝O)-Z₁Wherein M is Li, Na, K, Rb or Cs, Z₁ are any members selected from the group consisting of alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy, and haloaryloxy₁Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20. In particular, Z is₁May be but is not limited to-CF₃，-CF₂CF₃，-CF₂CF₂CF₂CF₃，-CF₂CF₂CF₂H，-CH₂CF₃And the like.

For example, when preparing the conductive polymer alkali metal salt shown in the formula (2) of the embodiment of the invention, in the embodiment , the polymer monomer simultaneously comprises a compound shown in the formula (4) and a five-membered unsaturated heterocyclic compound of which the 3-position and the 4-position are not substituted by the substituted imine alkali metal salt.

In an embodiment of the present invention, the initiator includes, but is not limited to, Azobisisobutyronitrile (AIBN), dibenzoyl peroxide (BPO), potassium persulfate, hydrogen peroxide-ferrous chloride, anhydrous ferric chloride, and the like.

In an embodiment of the present invention, the molar ratio of the polymer monomer to the initiator is 1:0.1 to 8, and further , the molar ratio may be 1:0.2 to 1, 1:2 to 6.

In an embodiment of the present invention, the solvent includes or more of ethane, cyclohexane, dichloromethane, chloroform, diethyl ether, petroleum ether, benzene, toluene, chlorobenzene, fluorobenzene, acetone, acetonitrile, methanol, ethanol, tetrahydrofuran, nitromethane, dimethyl sulfoxide, N-dimethylformamide, ethyl acetate, and butyl acetate.

In the embodiment of the invention, stirring is carried out in the polymerization reaction process, after the reaction is finished, filtering, drying under reduced pressure, recrystallizing by ethanol/toluene, filtering, washing, and drying in vacuum at 40-80 ℃ for 12-48 hours to obtain the conductive polymer alkali metal salt with heat-sensitive property.

In an embodiment of the present invention, the polymer monomer may be prepared as follows:

a) reacting a halogen-substituted five-membered unsaturated heterocyclic compound with a substituted amine compound at 0-60 ℃ for 6-48 hours in the presence of an acid-binding agent and a solvent to obtain amine salt, wherein the substituted amine compound comprises or more of substituted amide compounds and substituted sulfonamide compounds;

b) and under the protection of inert gas, reacting the amine salt with anhydrous alkali carbonate at 0-30 ℃ for 2-24 hours to obtain alkali metal salt, thus obtaining the polymer monomer.

In an embodiment of the present invention, the chemical formula of the substituted amide compound is Z₁-C(＝O)-NH₂The chemistry of the substituted sulfonamide compoundsThe expression is Z₂-S(＝O)₂-NH₂Z is the same as₁And Z₂ kinds selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy.

In the embodiment of the invention, the structural formula of the halogen-substituted five-membered unsaturated heterocyclic compound is shown as a formula (5), wherein the groups at the 3-position and the 4-position are respectively R₃And R₄Said R is₃And R₄Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₃And R₄At least is fluorine, chlorine, bromine or iodine.

In an embodiment of the present invention, the halogen-substituted five-membered unsaturated heterocyclic compound includes at least kinds of halogen-substituted thiophene, halogen-substituted furan and halogen-substituted pyrrole, and specifically, the halogen-substituted five-membered unsaturated heterocyclic compound includes, but is not limited to, 3-bromo-substituted thiophene, 3, 4-dichloro-substituted thiophene, 3-chloro-4-bromo-substituted thiophene, 3, 4-dibromo-substituted thiophene, 3-bromo-4-n-butyl-substituted thiophene, 3-bromo-4-n-octyl-substituted thiophene, 3-bromo-substituted furan, 3, 4-dichloro-substituted furan, 3-chloro-4-bromo-substituted furan, 3, 4-dibromo-substituted furan, 3-bromo-4-n-butyl-substituted pyrrole, 3-bromo-4-n-octyl-substituted furan, 3-bromo-4-n-octyl-substituted pyrrole, 3-bromo-4-substituted pyrrole, 3-bromo-octyl-substituted pyrrole, 3-4-bromo-substituted pyrrole, 3-bromo-4-octyl-substituted pyrrole, 3-bromo-octyl-substituted pyrrole, etc.

In the embodiment of the invention, the acid-binding agent comprises at least of triethylamine, N-dimethylcyclohexylamine, pyridine, pyrimidine and quinoline.

In an embodiment of the present invention, the anhydrous alkali metal carbonate includes kinds or more of anhydrous lithium carbonate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous rubidium carbonate, and anhydrous cesium carbonate.

In an embodiment of the invention, the molar ratio of the halogen-substituted five-membered unsaturated heterocyclic compound to the acid-binding agent is 1:1-1:10, further is 1:2-1:7, further is 1:3-1:5, the molar ratio of the halogen-substituted five-membered unsaturated heterocyclic compound to the substituted amine compound is 1:1-1:8, further is 1:2-1:6, further is 1:3-1:5, the molar ratio of the amine salt to the anhydrous alkali metal carbonate is 1:1-1:10, further is 1:2-1:7, further is 1:3-1: 5.

The alkali metal salt of a conductive polymer having a heat-sensitive characteristic provided in the embodiments of the present invention may be applied to a secondary battery in various ways to improve the safety and electrochemical performance of the battery.

Specifically, the embodiment of the invention provides composite current collectors, which include a current collector body and heat-sensitive material layers disposed on the side surface or both side surfaces of the current collector body , where the heat-sensitive material layers include the above-mentioned conductive polymer alkali metal salt with heat-sensitive property of the invention, fig. 1 and 2 are respectively schematic structural diagrams of composite current collectors in two embodiments of the invention, in an embodiment of the invention, as shown in fig. 1, the composite current collector includes a current collector body 10 and a heat-sensitive material layer 20 disposed on the side surface of the current collector body 10 , in another embodiment of the invention, as shown in fig. 2, the composite current collector includes a current collector body 10 and heat-sensitive material layers 20 disposed on both side surfaces of the current collector body 10.

In the embodiment of the present invention, the thermosensitive material layer 20 further includes a binder, and the conductive polymer alkali metal salt having thermosensitive property is fixed in the thermosensitive material layer 20 by the binder. The conductive polymer alkali metal salt having heat-sensitive characteristics is uniformly dispersed in the heat-sensitive material layer 20.

In the heat-sensitive material layer 20, the mass ratio of the alkali metal salt of the conductive polymer having heat-sensitive characteristics to the binder is 1-100:1, and further may be 50-95: 1. the binder may be one or more of polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), Polyacrylonitrile (PAN), Polyimide (PI), polyethylene glycol (PEG), polyethylene oxide (PEO), Polydopamine (PDA), sodium carboxymethylcellulose/styrene butadiene rubber (CMC/SBR), polyvinyl alcohol (PVA), polyacrylic acid (PAA), lithium polyacrylate (lipa), polyvinylpyrrolidone (PVP), polylactic acid (PLA), Sodium Alginate (SA), polyethylene terephthalate sulfonic acid (PSS), lithium polyethylene terephthalate (LiPSS), and gelatin .

In the embodiment of the present invention, the thickness of the thermosensitive material layer 20 is 0.01 μm to 10 μm, and further may be 1 μm to 8 μm, 3 μm to 6 μm, 5 μm to 7 μm.

In embodiments of the present invention, the current collector body may be an existing conventional commercial current collector, including but not limited to aluminum foil, copper foil, carbon-coated aluminum foil, and the like.

Accordingly, embodiments of the present invention provide secondary batteries, including a positive electrode current collector, a negative electrode including a negative electrode current collector, and a separator and an electrolyte disposed between the positive electrode and the negative electrode, the secondary battery having excellent safety and electrochemical properties due to the introduction of the above-described conductive polymer alkali metal salt having heat sensitive characteristics of the embodiments of the present invention into the current collector.

As shown in fig. 3, the embodiment of the present invention further provides electrode materials 30, which include an electrode active material 110 and a coating layer 120 disposed on the surface of the electrode active material 110, where the coating layer 120 includes the above-mentioned conductive polymer alkali metal salt having heat-sensitive property according to the embodiment of the present invention, and the electrode active material is a positive electrode active material or a negative electrode active material.

In the embodiment of the present invention, the thickness of the coating layer 120 is 1nm to 10 μm, and further may be 2nm to 1 μm, 10nm to 3 μm, or 100nm to 5 μm.

In the embodiment of the present invention, the positive electrode active material and the negative electrode active material are conventional materials, and the present invention is not particularly limited. The positive electrode active material may be, for example, lithium cobaltate or the like, and the negative electrode active material may be, for example, graphite or the like. The coating layer may be prepared to the surface of the electrode active material by an existing conventional slurry pulping method.

The embodiment of the invention also provides electrode sheets, which comprise a current collector and an electrode active material layer arranged on the current collector, wherein the electrode active material layer comprises the conductive polymer alkali metal salt with the heat-sensitive property, and the electrode sheet is a positive electrode sheet or a negative electrode sheet.

In the embodiment of the invention, as shown in fig. 4, the electrode sheet comprises a current collector 210 and an electrode active material layer 220 disposed on the current collector 210, the electrode active material layer 220 comprises a conductive polymer alkali metal salt 23 with heat-sensitive property and an electrode active material 110, the conductive polymer alkali metal salt 23 with heat-sensitive property is uniformly dispersed in the electrode active material layer 220, the electrode active material layer 220 further comprises a conductive agent, a binder and the like, and the electrode active material 110 can be a positive electrode active material or a negative electrode active material.

In the embodiment of the present invention, the alkali metal salt 23 of the conductive polymer having a heat-sensitive property accounts for 0.1% to 20%, further % to 1% to 10%, and further 2% to 6% of the total mass of the electrode active material layer 220.

In another embodiment of the present invention, as shown in fig. 5, the electrode sheet comprises a current collector 210 and an electrode active material layer 220 disposed on the current collector 210, wherein the electrode active material layer 220 comprises the electrode material 30 and the conductive agent 40 according to the embodiment of the present invention, specifically, in a mode is practicable, if the alkali metal salt of the conductive polymer having heat-sensitive property is dissolved in a slurry solvent during electrode pulping, the final alkali metal salt may exist on the surface of the electrode active material layer in the form of a coating layer.

Accordingly, the embodiment of the invention also provides kinds of secondary batteries, which comprise a positive electrode, a negative electrode, a diaphragm and an electrolyte, wherein the diaphragm and the electrolyte are arranged between the positive electrode and the negative electrode, and the positive electrode and/or the negative electrode comprise the electrode plate in the embodiment of the invention.

The embodiment of the invention also provides composite diaphragms, which comprise a diaphragm body and heat-sensitive material layers arranged on the side surface or two side surfaces of the diaphragm body , wherein the heat-sensitive material layers comprise the conductive polymer alkali metal salt with heat-sensitive property, which is disclosed in the embodiment of the invention, fig. 6 and 7 are respectively schematic structural diagrams of the composite diaphragms in two embodiments of the invention, in an embodiment of the invention, as shown in fig. 6, the composite diaphragm comprises a diaphragm body 50 and a heat-sensitive material layer 60 arranged on the side surface of the diaphragm body 50 , in another embodiment of the invention, as shown in fig. 7, the composite diaphragm comprises a diaphragm body 50 and heat-sensitive material layers 60 arranged on the two side surfaces of the diaphragm body 50.

In the embodiment of the present invention, the heat-sensitive material layer 60 further includes a binder, and the conductive polymer alkali metal salt having heat-sensitive property is fixed in the heat-sensitive material layer 60 by the binder. The conductive polymer alkali metal salt having heat-sensitive characteristics is uniformly dispersed in the heat-sensitive material layer 60.

In the heat-sensitive material layer 60, the mass ratio of the alkali metal salt of the conductive polymer having heat-sensitive characteristics to the binder is 1-100:1, and further may be 50-95: 1. the binder may be one or more of polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), Polyacrylonitrile (PAN), Polyimide (PI), polyethylene glycol (PEG), polyethylene oxide (PEO), Polydopamine (PDA), sodium carboxymethylcellulose/styrene butadiene rubber (CMC/SBR), polyvinyl alcohol (PVA), polyacrylic acid (PAA), lithium polyacrylate (lipa), polyvinylpyrrolidone (PVP), polylactic acid (PLA), Sodium Alginate (SA), polyethylene terephthalate sulfonic acid (PSS), lithium polyethylene terephthalate (LiPSS), and gelatin .

In the embodiment of the present invention, the thickness of the thermosensitive material layer 60 is 0.01 μm to 10 μm, and further may be 1 μm to 8 μm, 3 μm to 6 μm, 5 μm to 7 μm.

In embodiments of the present invention, the separator body may be an existing conventional commercial separator, including but not limited to, a single layer PP (polypropylene), a single layer PE (polyethylene), a double layer PP/PE, a double layer PP/PP, and a triple layer PP/PE/PP separator.

Accordingly, the embodiment of the invention provides secondary batteries, which comprise a positive electrode, a negative electrode, a diaphragm and an electrolyte, wherein the diaphragm and the electrolyte are arranged between the positive electrode and the negative electrode, the diaphragm adopts the composite diaphragm of the embodiment of the invention, and the secondary batteries comprise a lithium secondary battery, a sodium secondary battery, a potassium secondary battery and the like.

The following describes an example of the present invention in terms of several examples at step .

Example 1

Modifying a current collector by adopting poly (4-n-octyl substituted thiophene) (trifluoromethyl sulfonyl) lithium imide (shown as a formula (D)) and applying the modified current collector to a lithium secondary battery, wherein the method comprises the following steps:

(1) the preparation of poly (4-n-octyl substituted thiophene) (trifluoromethyl sulfonyl) lithium imide (D) has the synthetic route shown in formula (6):

a) respectively adding 0.5mol of 3-bromo-4-n-octyl substituted thiophene, 1.1mol of triethylamine and 500mL of dichloromethane solvent into a 1000mL three-neck flask, slowly adding 0.5mol of trifluoromethyl sulfonamide into the three-neck flask at the temperature of 30 ℃, stirring for reacting for 18 hours, filtering, and drying under reduced pressure to obtain (4-n-octyl substituted thiophene) (trifluoromethyl sulfonyl) imine triethylamine salt;

b) respectively adding 0.25mol of (4-n-octyl substituted thiophene) (trifluoromethyl sulfonyl) imine triethylamine salt and 250mL of acetonitrile solvent into a 500mL three-neck flask under the protection of argon, adding 0.5mol of anhydrous lithium carbonate solid into the three-neck flask in three batches at the temperature of 25 ℃, stirring for reacting for 6 hours, filtering after the reaction is finished, and drying under reduced pressure to obtain (4-n-octyl substituted thiophene) (trifluoromethyl sulfonyl) imine lithium;

c) under the protection of argon, 1.0mol of anhydrous ferric trichloride and 250mL of acetonitrile solvent are respectively added into a 500mL three-neck flask, 0.2mol of (4-n-octyl substituted thiophene) (trifluoromethyl sulfonyl) lithium imide is slowly added into the three-neck flask at the temperature of 0 ℃, stirred and reacted for 12 hours, after the reaction is finished, filtered, decompressed and dried, then recrystallized by ethanol/toluene, filtered, washed, and vacuum-dried for 24 hours at the temperature of 60 ℃, and the poly (4-n-octyl substituted thiophene) (trifluoromethyl sulfonyl) lithium imide (D) is obtained, wherein the yield is 86%.

(2) Preparing a composite current collector:

weighing 90 mass percent of lithium poly (4-N-octyl substituted thiophene) (trifluoromethyl sulfonyl) imide (D) and 10 mass percent of polyvinylidene fluoride (PVDF), dissolving the lithium poly (4-N-octyl substituted thiophene) (trifluoromethyl sulfonyl) imide (D) and the PVDF in N-methylpyrrolidone (NMP), stirring and mixing the solution to form a uniform solution, and uniformly coating the solution on two surfaces of an aluminum foil current collector by using a 1-micrometer scraper to prepare the composite current collector disclosed in the embodiment 1 of the invention.

(3) Preparation of lithium secondary battery:

weighing 2% of polyvinylidene fluoride (PVDF), 2% of conductive agent super P and 96% of lithium cobaltate (LiCoO) in percentage by mass₂) Sequentially adding the mixture into NMP, fully stirring and uniformly mixing to obtain slurry, coating the slurry on the composite current collector prepared in the embodiment 1, and drying, cold pressing and slitting to prepare the positive pole piece. Weighing 2 mass percent of CMC, 3 mass percent of SBR, 1 mass percent of acetylene black and 94 mass percent of graphite, sequentially adding the materials into deionized water, fully stirring and mixing the materials uniformlyUniformly obtaining slurry, coating the slurry on a copper foil current collector, drying, cold pressing and slitting to obtain a negative pole piece; preparing the prepared positive pole piece, negative pole piece and commercial PP/PE/PP three-layer diaphragm into a battery cell, packaging by adopting a polymer, and pouring 1.0mol/L LiPF₆And (3) preparing the electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) into the soft package lithium secondary battery of about 3.9Ah through chemical synthesis and other processes.

Example 2

Modifying a current collector by adopting poly (4-n-heptane-substituted furan) (hexafluoropropyl sulfonyl) lithium imide (shown as a formula (G)) and applying the modified current collector to a lithium secondary battery, wherein the method comprises the following steps:

(1) the preparation of poly (4-n-heptane substituted furan) (hexafluoropropyl sulfonyl) lithium (G) imide has the synthetic route shown in the formula (7):

a) respectively adding 0.5mol of 3-bromo-4-n-heptane substituted furan, 1.1mol of triethylamine and 500mL of dichloromethane solvent into a 1000mL three-neck flask, slowly adding 0.5mol of hexafluoropropyl sulfonamide into the three-neck flask at the temperature of 30 ℃, stirring for reacting for 18 hours, filtering, and drying under reduced pressure to obtain (4-n-heptane substituted furan) (hexafluoropropyl sulfonyl) imide triethylamine salt;

b) respectively adding 0.25mol of (4-n-heptane-substituted furan) (hexafluoropropyl sulfonyl) imide triethylamine salt and 250mL of acetonitrile solvent into a 500mL three-neck flask under the protection of argon, adding 0.5mol of anhydrous lithium carbonate solid into the three-neck flask in three batches at the temperature of 25 ℃, stirring and reacting for 6 hours, filtering after the reaction is finished, and drying under reduced pressure to obtain (4-n-heptane-substituted furan) (hexafluoropropyl sulfonyl) imide lithium;

c) under the protection of argon, 1.0mol of anhydrous ferric chloride and 250mL of acetonitrile solvent are respectively added into a 500mL three-neck flask, 0.2mol of (4-n-heptane-substituted furan) (hexafluoropropyl sulfonyl) lithium imide is slowly added into the three-neck flask at the temperature of 0 ℃, stirred and reacted for 12 hours, after the reaction is finished, filtered, decompressed and dried, and then recrystallized by ethanol/toluene, filtered, washed and dried in vacuum at the temperature of 60 ℃ for 24 hours to obtain the poly (4-n-heptane-substituted furan) (hexafluoropropyl sulfonyl) lithium imide (G), and the yield is 83%.

(2) Preparing a composite current collector:

weighing 90 mass percent of lithium (G) poly (4-N-heptane-substituted furan) (hexafluoropropyl sulfonyl) imide and 10 mass percent of PVDF, dissolving the lithium (G) poly (4-N-heptane-substituted furan) (hexafluoropropyl sulfonyl) imide and the PVDF in N-methylpyrrolidone (NMP), stirring and mixing the solution to form a uniform solution, and uniformly coating the uniform solution on two sides of a copper foil current collector by using a scraper with the diameter of 1 mu m to prepare the composite current collector in the embodiment 2 of the invention.

(3) Preparation of lithium secondary battery:

weighing 2% of polyvinylidene fluoride (PVDF), 2% of conductive agent super P and 96% of lithium cobaltate (LiCoO) in percentage by mass₂) Sequentially adding the materials into NMP, fully stirring and uniformly mixing to obtain slurry, coating the slurry on an aluminum foil current collector, drying, cold pressing and cutting to obtain the positive pole piece. Weighing 2% of CMC, 3% of SBR, 1% of acetylene black and 94% of graphite in percentage by mass, sequentially adding the materials into deionized water, fully stirring and uniformly mixing to obtain slurry, coating the slurry on the composite current collector of the embodiment 2 of the invention, and drying, cold pressing and slitting to obtain a negative pole piece; preparing the prepared positive pole piece, negative pole piece and commercial PP/PE/PP three-layer diaphragm into a battery cell, packaging by adopting a polymer, and pouring 1.0mol/L LiPF₆And (3) preparing the electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) into the soft package lithium secondary battery of about 3.9Ah through chemical synthesis and other processes.

Comparative example 1

The current collector is modified by poly (3-n-octyl substituted) thiophene (P3OT) and is applied to a lithium secondary battery, and the method comprises the following steps:

(1) preparing a composite current collector:

weighing 90 mass percent of poly (3-N-octyl substituted) thiophene (P3OT) and 10 mass percent of PVDF, dissolving the poly (3-N-octyl substituted) thiophene and the PVDF in N-methylpyrrolidone (NMP), stirring the mixture to form a uniform solution, and uniformly coating the uniform solution on two sides of an aluminum foil current collector by using a scraper with the diameter of 1 mu m to prepare the composite current collector of the comparative example 1.

(2) Preparation of lithium secondary battery:

weighing 2% of polyvinylidene fluoride (PVDF), 2% of conductive agent super P and 96% of lithium cobaltate (LiCoO) in percentage by mass₂) Sequentially adding the materials into NMP, fully stirring and uniformly mixing to obtain slurry, coating the slurry on the composite current collector of the comparative example 1, and drying, cold pressing and slitting to obtain the positive pole piece. Weighing 2% of CMC, 3% of SBR, 1% of acetylene black and 94% of graphite in percentage by mass, sequentially adding the materials into deionized water, fully stirring and uniformly mixing to obtain slurry, coating the slurry on a copper current collector, and drying, cold pressing and cutting to obtain a negative pole piece; preparing the prepared positive pole piece, negative pole piece and commercial PP/PE/PP three-layer diaphragm into a battery cell, packaging by adopting a polymer, and pouring 1.0mol/L LiPF₆And (3) preparing the electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) into the soft package lithium secondary battery of about 3.9Ah through chemical synthesis and other processes.

The lithium secondary batteries manufactured in examples 1 to 2 of the present invention and comparative example 1 were subjected to the following tests:

(1) and (4) safety performance testing: a high-temperature-resistant steel needle with the diameter of 3-8mm is adopted to carry out a needle punching experiment on the lithium secondary battery at the speed of 10-40mm/s, and whether the battery core is on fire or not is recorded, and the result is shown in table 1.

(2) And (3) rate performance test: rate capability test was performed on lithium secondary batteries at charge and discharge rates of 0.2/0.2C, 0.2/0.5C, 0.2/1.0C, 0.2/1.5C and 0.2/2.0C, graphite/LiCoO₂The voltage range of the battery was 3.0-4.4V, and the test results are shown in Table 1.

Table 1 results of testing safety and rate capability of batteries corresponding to different conductive polymer modified composite current collectors

As can be seen from the test results in table 1, the batteries of examples 1 and 2 according to the present invention did not cause ignition when subjected to the needle punching test, whereas the batteries of comparative example 1 did not cause ignition when subjected to the needle punching test, indicating that the batteries containing the conductive polymer-modified composite current collector grafted with a substituted lithium imide salt according to examples of the present invention had higher flame resistance and that their resistance sharply increased, and the current was interrupted, and the safety of the lithium secondary battery was improved when the temperature of the batteries increased beyond constant temperature (curie temperature).

In addition, as can be seen from the test results in table 1, compared with comparative example 1, the batteries in examples 1 and 2 of the present invention have better rate performance, which is mainly because the conductive polymer grafted with the substituted imine lithium salt in the examples of the present invention has not only excellent thermal sensitivity and electronic conductivity, but also good ion conductivity, and can effectively increase the mobility of lithium ions, which is beneficial to the transmission of lithium ions, thereby increasing the rate performance of the lithium secondary battery.

Example 3

The method is characterized in that poly (4-n-octyl substituted thiophene) (pentafluoroethyl sulfonyl) imide lithium (shown as a formula (E)) is adopted to modify an electrode plate and is applied to a lithium secondary battery, and the method comprises the following steps:

(1) the preparation of poly (4-n-octyl substituted thiophene) (pentafluoroethylsulfonyl) lithium imide (E) has a synthetic route shown in a formula (8):

a) respectively adding 0.5mol of 3-bromo-4-n-octyl substituted thiophene, 1.1mol of triethylamine and 500mL of dichloromethane solvent into a 1000mL three-neck flask, slowly adding 0.5mol of pentafluoroethyl sulfonamide into the three-neck flask at the temperature of 30 ℃, stirring for reacting for 18 hours, filtering, and drying under reduced pressure to obtain (4-n-octyl substituted thiophene) (pentafluoroethyl sulfonyl) imine triethylamine salt;

b) respectively adding 0.25mol of (4-n-octyl substituted thiophene) (pentafluoroethylsulfonyl) imine triethylamine salt and 250mL of acetonitrile solvent into a 500mL three-neck flask under the protection of argon, adding 0.5mol of anhydrous lithium carbonate solid into the three-neck flask in three batches at the temperature of 25 ℃, stirring and reacting for 6 hours, filtering after the reaction is finished, and drying under reduced pressure to obtain (4-n-octyl substituted thiophene) (pentafluoroethylsulfonyl) imine lithium;

c) under the protection of argon, 1.0mol of anhydrous ferric chloride and 250mL of acetonitrile solvent are respectively added into a 500mL three-neck flask, 0.2mol of (4-n-octyl substituted thiophene) (pentafluoroethylsulfonyl) lithium imide is slowly added into the three-neck flask at the temperature of 0 ℃, the mixture is stirred and reacted for 12 hours, after the reaction is finished, the mixture is filtered, decompressed and dried, then ethanol/toluene is used for recrystallization, suction filtration and washing are carried out, vacuum drying is carried out for 24 hours at the temperature of 60 ℃, and the poly (4-n-octyl substituted thiophene) (pentafluoroethylsulfonyl) lithium imide (E) is obtained, wherein the yield is 85%.

(2) Preparing a positive pole piece:

weighing 2 mass percent of lithium poly (4-n-octyl substituted thiophene) (pentafluoroethylsulfonyl) imide (E), 1 mass percent of polyvinylidene fluoride (PVDF) and 95 mass percent of lithium cobaltate (LiCoO)₂) Dissolving the mixture in N-methylpyrrolidone (NMP), stirring and mixing the mixture to form a uniform solution, then weighing polyvinylidene fluoride (PVDF) with the mass percentage of 1% and a conductive agent super P with the mass percentage of 1% and sequentially adding the polyvinylidene fluoride (PVDF) and the conductive agent super P into the solution, fully stirring and uniformly mixing the mixture to obtain slurry, coating the slurry on an aluminum foil current collector, and drying, cold pressing and cutting the aluminum foil current collector to obtain the positive pole piece (the structural schematic diagram is shown in figure 5) in the embodiment 3 of the invention.

(3) Preparation of lithium secondary battery:

weighing 2% of CMC, 3% of SBR, 1% of acetylene black and 94% of graphite in percentage by mass, sequentially adding the materials into deionized water, fully stirring and uniformly mixing to obtain slurry, coating the slurry on a copper foil current collector, drying, cold pressing and slitting to obtain a negative pole piece; preparing the prepared positive pole piece, negative pole piece and commercial PP/PE/PP three-layer diaphragm into a battery cell, packaging by adopting a polymer, and pouring 1.0mol/L LiPF₆And (3) preparing the electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) into the soft package lithium secondary battery of about 3.9Ah through chemical synthesis and other processes.

Example 4

Poly (4-n-hexane substituted pyrrole) (trifluoroethylsulfonyl) imide lithium (shown as a formula (H)) is adopted to modify an electrode plate and is applied to a lithium secondary battery, and the method comprises the following steps:

(1) the preparation of poly (4-n-hexane substituted pyrrole) (trifluoroethylsulfonyl) lithium imide (H) has a synthetic route shown as a formula (9):

a) respectively adding 0.5mol of 3-bromo-4-n-hexane substituted pyrrole, 1.1mol of triethylamine and 500mL of dichloromethane solvent into a 1000mL three-neck flask, slowly adding 0.5mol of trifluoroethyl sulfonamide into the three-neck flask at the temperature of 30 ℃, stirring for reacting for 18 hours, filtering, and drying under reduced pressure to obtain (4-n-hexane substituted pyrrole) (trifluoroethylsulfonyl) imide triethylamine salt;

b) respectively adding 0.25mol of (4-n-hexane-group substituted pyrrole) (trifluoroethylsulfonyl) imine triethylamine salt and 250mL of acetonitrile solvent into a 500mL three-neck flask under the protection of argon, adding 0.5mol of anhydrous lithium carbonate solid into the three-neck flask in three batches at the temperature of 25 ℃, stirring and reacting for 6 hours, filtering after the reaction is finished, and drying under reduced pressure to obtain (4-n-hexane-group substituted pyrrole) (trifluoroethylsulfonyl) imine lithium;

c) under the protection of argon, 1.0mol of anhydrous ferric chloride and 250mL of acetonitrile solvent are respectively added into a 500mL three-neck flask, 0.2mol of (4-n-hexane group substituted pyrrole) (trifluoroethylsulfonyl) lithium imide is slowly added into the three-neck flask at the temperature of 0 ℃, the mixture is stirred and reacted for 12 hours, after the reaction is finished, the mixture is filtered, decompressed and dried, and then recrystallized by ethanol/toluene, filtered, washed and dried in vacuum at the temperature of 60 ℃ for 24 hours, so that poly (4-n-hexane group substituted pyrrole) (trifluoroethylsulfonyl) lithium imide (H) is obtained, and the yield is 81%.

(2) Preparing a negative pole piece:

weighing poly (4-n-hexane-based substituted pyrrole) (trifluoroethylsulfonyl) lithium imide (H) with the mass percentage of 2%, 93% of graphite, 1.5% of CMC, 2.5% of SBR and 1% of acetylene black, dissolving the materials in deionized water, fully stirring and uniformly mixing the materials to obtain slurry, coating the slurry on a copper foil current collector, drying, cold pressing and slitting the copper foil current collector to obtain the negative pole piece (the structural schematic diagram is shown in figure 4) of the embodiment 4 of the invention.

(3) Preparation of lithium secondary battery:

weighing 2% of polyvinylidene fluoride (PVDF), 2% of conductive agent super P and 96% of lithium cobaltate (LiCoO) in percentage by mass₂) Sequentially adding into N-methylpyrrolidone (NMP), fully stirring and uniformly mixing to obtainSlurry, coating the slurry on an aluminum foil current collector, drying, cold-pressing and cutting to obtain a positive pole piece; preparing the prepared positive pole piece, negative pole piece and commercial PP/PE/PP three-layer diaphragm into a battery cell, packaging by adopting a polymer, and pouring 1.0mol/L LiPF₆And (3) preparing the electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) into the soft package lithium secondary battery of about 3.9Ah through chemical synthesis and other processes.

Comparative example 2

The preparation of the lithium secondary battery is carried out by adopting the electrode plate of the conventional commercial lithium secondary battery:

weighing 2% of polyvinylidene fluoride (PVDF), 2% of conductive agent super P and 96% of lithium cobaltate (LiCoO) in percentage by mass₂) Sequentially adding the aluminum foil into N-methylpyrrolidone (NMP), fully stirring and uniformly mixing to obtain slurry, coating the slurry on an aluminum foil current collector, drying, cold pressing and cutting to obtain a positive pole piece; weighing 2% of CMC, 3% of SBR, 1% of acetylene black and 94% of graphite in percentage by mass, sequentially adding the materials into deionized water, fully stirring and uniformly mixing to obtain slurry, coating the slurry on a copper foil current collector, drying, cold pressing and slitting to obtain a negative pole piece; preparing the prepared positive pole piece, negative pole piece and commercial PP/PE/PP three-layer diaphragm into a battery cell, packaging by adopting a polymer, and pouring 1.0mol/L LiPF₆And (3) preparing the electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) into the soft package lithium secondary battery of about 3.9Ah through chemical synthesis and other processes.

The lithium secondary batteries manufactured in examples 3 to 4 of the present invention and comparative example 2 were subjected to the following tests:

(1) and (4) safety performance testing: a high-temperature-resistant steel needle with the diameter of 3-8mm is adopted to carry out a needle punching experiment on the lithium secondary battery at the speed of 10-40mm/s, and whether the battery core is on fire or not is recorded, and the result is shown in Table 2.

(2) And (3) rate performance test: rate capability test was performed on lithium secondary batteries at charge and discharge rates of 0.2/0.2C, 0.2/0.5C, 0.2/1.0C, 0.2/1.5C and 0.2/2.0C, graphite/LiCoO₂The voltage range of the battery was 3.0-4.4V, and the test results are shown in Table 2.

TABLE 2 safety and rate capability test results of different conductive polymer modified electrode sheets corresponding to batteries

As can be seen from the test results in table 2, the batteries of examples 3 and 4 according to the present invention did not suffer from ignition when subjected to the needle punching test, whereas the batteries of comparative example 2 suffered from ignition when subjected to the needle punching test, indicating that the batteries of examples according to the present invention comprising the conductive polymer-modified electrode sheet grafted with a substituted lithium imide salt had higher flame resistance, and when the temperature of the batteries increased beyond constant temperature (curie temperature), the resistance thereof sharply increased, the current was interrupted, and the safety of the lithium secondary batteries was improved.

In addition, as can be seen from the test results in table 2, compared with comparative example 2, the batteries in examples 3 and 4 of the present invention have better rate performance, which is mainly because the conductive polymer grafted with the substituted imine lithium salt in the examples of the present invention has not only excellent thermal sensitivity and electronic conductivity, but also good ion conductivity, and can effectively improve the mobility of lithium ions, which is beneficial to the transmission of lithium ions, thereby improving the rate performance of the lithium secondary battery.

Example 5

The method for modifying the diaphragm by adopting the lithium poly (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) imide (shown as the formula (F)) and applying the diaphragm to the lithium secondary battery comprises the following steps:

(1) the preparation of poly (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) lithium imide (F) has a synthetic route shown in formula (10):

a) respectively adding 0.5mol of 3-bromo-4-n-octyl substituted thiophene, 1.1mol of triethylamine and 500mL of dichloromethane solvent into a 1000mL three-neck flask, slowly adding 0.5mol of perfluorobutanesulfonamide into the three-neck flask at the temperature of 30 ℃, stirring for reacting for 18 hours, filtering, and drying under reduced pressure to obtain (4-n-octyl substituted thiophene) (perfluorobutanesulfonyl) imide triethylamine salt;

b) respectively adding 0.25mol of (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) imide triethylamine salt and 250mL of acetonitrile solvent into a 500mL three-neck flask under the protection of argon, adding 0.5mol of anhydrous lithium carbonate solid into the three-neck flask in three batches at the temperature of 25 ℃, stirring for reacting for 6 hours, filtering after the reaction is finished, and drying under reduced pressure to obtain (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) imide lithium;

c) under the protection of argon, 1.0mol of anhydrous ferric trichloride and 250mL of acetonitrile solvent are respectively added into a 500mL three-neck flask, 0.2mol of (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) lithium imide is slowly added into the three-neck flask at the temperature of 0 ℃, stirred and reacted for 12 hours, after the reaction is finished, filtered, decompressed and dried, and then recrystallized by ethanol/toluene, filtered, washed and dried in vacuum at the temperature of 60 ℃ for 24 hours to obtain the poly (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) lithium imide (F), and the yield is 87%.

(2) Preparing a composite diaphragm:

weighing 90 mass percent of lithium (F) poly (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) imide and 10 mass percent of PVDF, dissolving the lithium (F) poly (4-n-octyl substituted thiophene) (perfluorobutylsulfonyl) imide and the 10 mass percent of PVDF in NMP, stirring and mixing to obtain a uniform solution, and uniformly coating the solution on surfaces of a PP diaphragm by using a 1 mu m scraper to obtain the composite diaphragm of the embodiment 5 of the invention.

(3) Preparation of lithium secondary battery:

weighing 2% of polyvinylidene fluoride (PVDF), 2% of conductive agent super P and 96% of lithium cobaltate (LiCoO) in percentage by mass₂) Sequentially adding the aluminum foil into N-methylpyrrolidone (NMP), fully stirring and uniformly mixing to obtain slurry, coating the slurry on an aluminum foil current collector, drying, cold pressing and cutting to obtain a positive pole piece; weighing 2% of CMC, 3% of SBR, 1% of acetylene black and 94% of graphite in percentage by mass, sequentially adding the materials into deionized water, fully stirring and uniformly mixing to obtain slurry, coating the slurry on a copper foil current collector, drying, cold pressing and slitting to obtain a negative pole piece; preparing the prepared positive pole piece, negative pole piece and composite diaphragm into a battery cell, packaging by adopting a polymer, and filling 1.0mol/L LiPF₆The electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) is prepared into the electrolyte3.9Ah of soft-packed lithium secondary battery.

Example 6

The diaphragm is modified by adopting poly (thiophene) (trifluoroacetyl) imide lithium (shown as a formula (A)) and is applied to a lithium secondary battery, and the method comprises the following steps:

(1) the preparation of poly (thiophene) (trifluoroacetyl) imine lithium (A) has a synthetic route shown as a formula (11):

a) respectively adding 0.5mol of 3-bromine substituted thiophene, 1.1mol of triethylamine and 500mL of dichloromethane solvent into a 1000mL three-neck flask, slowly adding 0.5mol of trifluoroacetamide into the three-neck flask at the temperature of 30 ℃, stirring for reacting for 18 hours, filtering, and drying under reduced pressure to obtain (thiophene) (trifluoroacetyl) imine triethylamine salt;

b) respectively adding 0.25mol of (thiophene) (trifluoroacetyl) imine triethylamine salt and 250mL of acetonitrile solvent into a 500mL three-neck flask under the protection of argon, adding 0.5mol of anhydrous lithium carbonate solid into the three-neck flask in three batches at 25 ℃, stirring and reacting for 6 hours, filtering after the reaction is finished, and drying under reduced pressure to obtain (thiophene) (trifluoroacetyl) imine lithium;

c) under the protection of argon, 1.0mol of anhydrous ferric trichloride and 250mL of acetonitrile solvent are respectively added into a 500mL three-neck flask, 0.2mol of lithium (thiophene) (trifluoroacetyl) imide is slowly added into the three-neck flask at the temperature of 0 ℃, the mixture is stirred and reacted for 12 hours, after the reaction is finished, the mixture is filtered, decompressed and dried, and then recrystallized by ethanol/toluene, filtered, washed and dried in vacuum at the temperature of 60 ℃ for 24 hours to obtain the lithium (A) poly (thiophene) (trifluoroacetyl) imide, wherein the yield is 82%.

(2) Preparing a composite diaphragm:

weighing 90 mass percent of lithium poly (thiophene) (trifluoroacetyl) imide (A) and 10 mass percent of PVDF, dissolving the lithium poly (thiophene) (trifluoroacetyl) imide (A) and the PVDF in NMP, stirring and mixing to obtain a uniform solution, and uniformly coating the solution on the surface of the PP membrane by using a 1-micrometer scraper to obtain the composite membrane of the embodiment 6 of the invention.

(3) Preparation of lithium secondary battery:

weighing 2% of polyvinylidene fluoride (PVDF), 2% of conductive agent super P and 96% of lithium cobaltate (LiCoO) in percentage by mass₂) Sequentially adding the aluminum foil into N-methylpyrrolidone (NMP), fully stirring and uniformly mixing to obtain slurry, coating the slurry on an aluminum foil current collector, drying, cold pressing and cutting to obtain a positive pole piece; weighing 2% of CMC, 3% of SBR, 1% of acetylene black and 94% of graphite in percentage by mass, sequentially adding the materials into deionized water, fully stirring and uniformly mixing to obtain slurry, coating the slurry on a copper foil current collector, drying, cold pressing and slitting to obtain a negative pole piece; preparing the prepared positive pole piece, negative pole piece and composite diaphragm into a battery cell, packaging by adopting a polymer, and filling 1.0mol/L LiPF₆And (3) preparing the electrolyte (EC, EMC, DEC, PC and FEC in a weight ratio of 30:25:30:10:5) into the soft package lithium secondary battery of about 3.9Ah through chemical synthesis and other processes.

Comparative example 3

The method for modifying the diaphragm by adopting poly (3-n-octyl substituted) thiophene (P3OT) and applying the diaphragm to the lithium secondary battery comprises the following steps:

(1) preparing a composite diaphragm:

weighing 90 mass percent of poly (3-n-octyl substituted) thiophene (P3OT) and 10 mass percent of PVDF (polyvinylidene fluoride) in NMP (N-methyl pyrrolidone), stirring and mixing to obtain a uniform solution, and uniformly coating the solution on the surface of a PP diaphragm by using a 1 mu m scraper to obtain the diaphragm of the comparative example 3;

(2) preparation of lithium secondary battery:

The lithium secondary batteries manufactured in examples 5 to 6 of the present invention and comparative example 3 were subjected to the following tests:

(1) and (4) safety performance testing: a high-temperature resistant steel needle with the diameter of 3-8mm is adopted to carry out a needle punching experiment on the lithium secondary battery at the speed of 10-40mm/s, and whether the battery core is on fire is recorded, and the result is shown in table 3.

(2) And (3) rate performance test: rate capability test was performed on lithium secondary batteries at charge and discharge rates of 0.2/0.2C, 0.2/0.5C, 0.2/1.0C, 0.2/1.5C and 0.2/2.0C, graphite/LiCoO₂The voltage range of the cell was 3.0-4.4V and the test results are shown in Table 3.

TABLE 3 test results of safety and rate capability of different conductive polymer modified composite diaphragms corresponding to batteries

As can be seen from the test results in table 3, the batteries of examples 5 and 6 according to the present invention did not ignite when subjected to the needle punching test, whereas the batteries of comparative example 3 ignited without igniting when subjected to the needle punching test, indicating that the batteries of examples according to the present invention having the conductive polymer-modified composite separator grafted with a substituted lithium imide salt had higher flame resistance and increased safety of the lithium secondary battery by sharply increasing the resistance and interrupting the current when the temperature of the battery increased beyond constant temperature (curie temperature).

In addition, as can be seen from the test results in table 3, compared with comparative example 3, the batteries in examples 5 and 6 of the present invention have better rate performance, which is mainly because the conductive polymer grafted with the substituted imine lithium salt in the examples of the present invention has not only excellent thermal sensitivity and electron conductivity, but also good ion conductivity, and can effectively increase the mobility of lithium ions, which is beneficial to the transmission of lithium ions, thereby increasing the rate performance of the lithium secondary battery.

Claims

The conductive polymer alkali metal salt with the heat-sensitive property is characterized by comprising a conductive polymer repeating unit and a substituted imine alkali metal salt grafted on the conductive polymer repeating unit, wherein the conductive polymer repeating unit comprises a five-membered unsaturated heterocyclic structure, the substituted imine alkali metal salt comprises or more of substituted imide alkali metal salt and substituted sulfonyl imide alkali metal salt, and the substituted imine alkali metal salt forms an N-C bond with a C atom in the five-membered unsaturated heterocyclic structure through an N atom.
2. The alkali metal salt of a conductive polymer having thermosensitive properties according to claim 1, wherein the chemical expression of the substituted imide alkali metal salt is-N (M)⁺)-C(＝O)-Z₁Wherein M is Li, Na, K, Rb or Cs, Z₁ kinds selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy.
3. The alkali metal salt of a conductive polymer having heat-sensitive properties according to claim 1 or 2, wherein the chemical expression of the substituted sulfonimide alkali metal salt is-N (M)⁺)-S(＝O)₂-Z₂Wherein M is Li, Na, K, Rb or Cs, Z₂ kinds selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy.
4. The alkali metal salt of a conductive polymer having heat-sensitive properties of any one of claims 1 to 3, , wherein the alkali metal salt of a conductive polymer comprises or more repeating units of the conductive polymer.
5. The alkali metal salt of a conductive polymer having thermal sensitivity of any one of claims 1-4 and , wherein the repeat unit of the conductive polymer comprises or more five-membered unsaturated heterocyclic structures.
6. The alkali metal salt of a conductive polymer with thermal sensitivity of any one of claims 1-5 and , wherein the five-membered unsaturated heterocyclic structure includes at least of thiophene, pyrrole and furan.
7. The alkali metal salt of a conductive polymer having thermal sensitivity of any one of claims 1-6 and , wherein the repeat unit of the conductive polymer comprises five-membered unsaturated heterocyclic ring structures, and the groups at positions 3 and 4 of the five-membered unsaturated heterocyclic ring structures are R respectively₁And R₂Said R is₁And R₂Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₁And R₂At least of (a) are the substituted imine alkali metal salt.
8. The alkali metal salt of a conductive polymer having thermal sensitivity of , wherein the repeating unit of the conductive polymer comprises a plurality of five-membered unsaturated heterocyclic structures, at least of all groups at the 3-and 4-positions of the five-membered unsaturated heterocyclic structures are the substituted imine alkali metal salt, and the rest of the groups are any groups selected from hydrogen, fluorine, chlorine, bromine, iodine, the substituted imine alkali metal salt, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy.
9. The alkali metal salt of a conductive polymer having heat-sensitive properties of claim 2, wherein Z is₁Wherein the alkyl group, the haloalkyl group, the alkoxy group, and the haloalkoxy group have 1 to 20 carbon atoms, and the alkenyl group, the haloalkenyl group, the alkenyloxy group, and the alkenyloxy group,The carbon atom number of the halogenated alkenyloxy is 2-20, and the carbon atom number of the aryl, the halogenated aryl, the aryloxy and the halogenated aryloxy is 6-20.
10. The alkali metal salt of a conductive polymer having heat-sensitive properties of claim 3, wherein Z is₂Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20.
11. The alkali metal salt of a conductive polymer having heat-sensitive properties of claim 7, wherein R is₁And R₂Wherein the number of carbon atoms of the alkyl group, the halogenated alkyl group, the alkoxy group and the halogenated alkoxy group is 1 to 20, the number of carbon atoms of the alkenyl group, the halogenated alkenyl group, the alkenyloxy group and the halogenated alkenyloxy group is 2 to 20, and the number of carbon atoms of the aryl group, the halogenated aryl group, the aryloxy group and the halogenated aryloxy group is 6 to 20.
12, A method for preparing an alkali metal salt of a conductive polymer having heat-sensitive properties, comprising the steps of:

reacting a polymer monomer at-40-100 ℃ for 6-48 hours in the presence of an initiator and a solvent, and polymerizing the polymer monomer to obtain a conductive polymer alkali metal salt with heat-sensitive characteristics, wherein the polymer monomer comprises a five-membered unsaturated heterocyclic structure and a substituted imine alkali metal salt positioned on the five-membered unsaturated heterocyclic structure, the conductive polymer alkali metal salt comprises a conductive polymer repeating unit and a substituted imine alkali metal salt grafted on the conductive polymer repeating unit, the conductive polymer repeating unit comprises a five-membered unsaturated heterocyclic structure, the substituted imine alkali metal salt comprises or more of a substituted imide alkali metal salt and a substituted sulfimide alkali metal salt, and the substituted imine alkali metal salt forms an N-C bond with a C atom in the five-membered unsaturated heterocyclic structure through an N atom.
13. The method of claim 12, wherein the polymer monomer is prepared by:

reacting a halogen-substituted five-membered unsaturated heterocyclic compound with a substituted amine compound in the presence of an acid-binding agent and a solvent at 0-60 ℃ for 6-48 hours to obtain an amine salt, wherein the substituted amine compound comprises or more of substituted amide compounds and substituted sulfonamide compounds;

under the protection of inert gas, reacting the amine salt with anhydrous alkali carbonate at 0-30 ℃ for 2-24 hours to obtain alkali metal salt, and obtaining the polymer monomer.
14. The method of claim 13, wherein the substituted amide compound has the chemical formula Z₁-C(＝O)-NH₂The chemical expression of the substituted sulfonamide compound is Z₂-S(＝O)₂-NH₂Z is the same as₁And Z₂ kinds selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy.
15. The method according to claim 13, wherein the halogen-substituted five-membered unsaturated heterocyclic compound comprises at least kinds of halogen-substituted thiophene, halogen-substituted furan and halogen-substituted pyrrole, and groups at positions 3 and 4 in the halogen-substituted five-membered unsaturated heterocyclic compound are R respectively₃And R₄Said R is₃And R₄Each selected from any of hydrogen, fluorine, chlorine, bromine, iodine, alkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, haloalkenyl, alkenyloxy, haloalkenyloxy, aryl, haloaryl, aryloxy and haloaryloxy, and the R is₃And R₄At least is fluorine, chlorine, bromine or iodine.
16. The method of claim 12, wherein the initiator comprises or more of azobisisobutyronitrile, dibenzoyl peroxide, potassium persulfate, hydrogen peroxide-ferrous chloride, and anhydrous ferric chloride, and the molar ratio of the polymer monomer to the initiator is 1: 0.1-8.
17. The preparation method of claim 13, wherein the molar ratio of the halogen-substituted five-membered unsaturated heterocyclic compound to the acid-binding agent is 1: 1-10; the molar ratio of the halogen substituted five-membered unsaturated heterocyclic compound to the substituted amine compound is 1: 1-8; the molar ratio of the amine salt to the anhydrous alkali carbonate is 1: 1-10.
18, composite current collector, comprising a current collector body and a heat sensitive material layer disposed on one or both side surfaces of the current collector body , wherein the heat sensitive material layer comprises the heat sensitive conductive polymer alkali metal salt according to any one of claims 1-11 and .
19. The composite current collector of claim 18, wherein the heat sensitive material layer further comprises a binder, and wherein the alkali metal salt of a conductive polymer having heat sensitive properties is fixed in the heat sensitive material layer by the binder.
20. The composite current collector of claim 18, wherein the mass ratio of the alkali metal salt of the conductive polymer having heat-sensitive properties to the binder in the heat-sensitive material layer is 1-100: 1.
21. The composite current collector of claim 18, wherein the thickness of the thermal sensitive material layer is 0.01 μ ι η to 10 μ ι η.
22, kinds of electrode material, characterized in that, it includes electrode active material and coating layer set on the surface of the electrode active material, the coating layer includes conducting polymer alkali metal salt with heat-sensitive property as described in any of claims 1-11, the electrode active material is positive electrode active material or negative electrode active material.
23. The electrode material of claim 22, wherein the coating has a thickness of 1nm to 10 μ ι η.
24, electrode sheet, comprising a current collector and an electrode active material layer disposed on the current collector, wherein the electrode active material layer comprises the conductive polymer alkali metal salt with heat-sensitive property according to any of claims 1-11, and the electrode sheet is a positive electrode sheet or a negative electrode sheet.
25, composite diaphragm, comprising a diaphragm body and a heat-sensitive material layer disposed on one or both side surfaces of the diaphragm body , wherein the heat-sensitive material layer comprises the heat-sensitive conductive polymer alkali metal salt according to any of claims 1-11.
26, secondary battery, comprising a positive electrode, a negative electrode, and a separator and an electrolyte arranged between the positive electrode and the negative electrode, wherein the positive electrode, the negative electrode and/or the separator comprise the conductive polymer alkali metal salt with heat-sensitive property of any of claims 1-11- .