CN111732724A

CN111732724A - Polyaryletherketone single-ion polymer and single-ion gel polymer electrolyte

Info

Publication number: CN111732724A
Application number: CN202010609894.XA
Authority: CN
Inventors: 呼微; 尤莹雪; 朱广山; 谢海明; 卢云峰; 刘佰军
Original assignee: Northeast Normal University
Current assignee: Northeast Normal University
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2020-10-02
Anticipated expiration: 2040-06-30
Also published as: CN111732724B

Abstract

The invention provides a polyaryletherketone single ion polymer which has a structural formula shown in a formula (II) below. According to the invention, organic lithium salt styrene sulfonyl (trifluoromethanesulfonyl) imide Lithium (LiSTFSI) with high dissociation degree is grafted on the polyaryletherketone, so that anions are fixed on a polyaryletherketone substrate, and only lithium ions move in a system, thereby improving the electrochemical performance and stability of the battery. The invention also provides a single ion gel polymer electrolyte, which is prepared by blending the polyaryletherketone single ion polymer and the functional polymer in solution and then adding a proper amount of plasticizer. The prepared single-ion gel polymer electrolyte greatly improves the conductivity and the thermal stability of lithium ion, and has excellent and stable battery performance and wide application prospect.

Description

Polyaryletherketone single-ion polymer and single-ion gel polymer electrolyte

Technical Field

The invention belongs to the technical field of lithium battery application, and particularly relates to a polyaryletherketone single-ion polymer and a single-ion gel polymer electrolyte prepared from the polyaryletherketone single-ion polymer.

Background

With the rapid development of social industrial economy, human beings consume a large amount of non-renewable energy sources such as petroleum, coal, natural gas and the like in a short time, and serious energy shortage and environmental pollution problems are caused. These problems have severely restricted global economic development in the 21 st century, and thus the development of continuously efficient clean energy is one of the major research fields in academia and industry at present. Lithium Ion Batteries (LIBs) are rechargeable electrical energy storage devices that have high energy density, good cycling stability, and are environmentally friendly. So far, lithium ion batteries have been widely used in the fields of portable electronic devices, electric vehicles, smart grids, and the like.

Lithium ion batteries typically include a separator to prevent short circuits due to contact between the positive and negative electrodes. The separator, which is one of the key components in the electrochemical reaction process, although not involved in the electrochemical reaction, plays an important role in the capacity, operating temperature range, cycle stability and safety of the battery together with the electrolyte. Currently commercialized lithium ion batteries generally use a liquid electrolyte and a porous Polyethylene (PE) or polypropylene (PP) separator. In the traditional porous PP/PE membrane system, concentration polarization is generated due to different migration rates of anions and cations in electrolyte, so that unstable crystal nuclei are formed on the surface of a lithium metal negative electrode to form lithium dendrites, and the problems of poor safety, low coulombic efficiency, short service life and the like of the lithium metal battery are caused. In addition, the use of liquid electrolyte causes serious safety problems such as leakage and combustion of the battery electrolyte. These problems have all seriously hindered the progress of commercialization of lithium metal secondary batteries. A single-ion polymer electrolyte (SIPE) fixes an anionic group on a polymer in a covalent bond form, so that only lithium ions in the system move. Lithium ions can be deposited more uniformly in the charging and discharging process, and the formation of lithium dendrites is relieved. Meanwhile, the leakage problem of the electrolyte in the lithium ion battery can be solved, and the safety of the lithium ion battery is improved. Therefore, the SIPE is adopted to replace the traditional diaphragm, so that the problem of lithium dendrite can be solved to a certain extent, and the battery performance and the safety of the lithium ion battery are improved.

SIPE is characterized in that the electrolyte system does not contain a plasticizer, so that the safety problem caused by the leakage of an organic solvent can be avoided. And the uniform deposition of lithium ions can be regulated and controlled to a certain extent, so that the protection effect on the negative electrode is achieved. The Single Ion Gel Polymer Electrolyte (SIGPE) combines the advantages of a single ion polymer electrolyte, in which there is little free organic solvent, and an electrolyte solution in which lithium ions can migrate in a manner similar to the conduction of lithium ions in an electrolyte. Therefore, the SIGPE not only improves the safety of the battery, but also has high ionic conductivity. Therefore, SIGPE has been intensively studied by researchers, and is expected to be applied to fields such as electric vehicles, electric tools, military, and spacecraft, which have high safety requirements.

The ion conductivity of the SIGPE prepared by the traditional method at room temperature can reach 2.67 × 10^-3S cm^-1At room temperature, performance requirements such as high ionic conductivity and high stability cannot be simultaneously met, and the problems directly restrict further application of the SIGPE. Researchers develop modified polyaryletherketone which can be used for lithium ion battery diaphragms, the polymer has good thermal stability, and allyl double bonds of the polymer can be introduced into polymer molecular chains as active groups to provide active sites. However, the battery assembled with the separator prepared according to this method generates concentration polarization during charge and discharge, and thus the safety and cycle performance of the battery are still unsatisfactory.

The single ion polymer is prepared by reacting flexible polymer or monomer with lithium salt, and although there are many rigid polymers with good thermal stability, the rigid polymer is rarely applied to the single ion polymer because the movement of the rigid polymer chain segment is poor. In the prior art, the SIGPE technology is that lithium salt is copolymerized on the main chain of a polymer to prepare a single-ion polymer, and the mobility of lithium ions of a battery assembled by the single-ion polymer is not high, so that the electrochemical performance of the battery is influenced.

Disclosure of Invention

In order to solve the technical problems, the invention tries to graft lithium salt on a rigid polymer with good thermal stability to prepare a single-ion polymer, so that the obtained single-ion gel polymer electrolyte can reduce concentration polarization generated in the charging and discharging process of the battery and improve the safety performance and the cycle performance of the battery. The invention aims to provide a polyaryletherketone single-ion polymer and a polyaryletherketone single-ion gel polymer electrolyte prepared from the polyaryletherketone single-ion polymer.

The first object of the present invention is to provide a polyaryletherketone monoionic polymer having a structural formula as shown in formula (II):

wherein R is₁、R₂、R₃、R₄Independently selected from C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkyl halide, C1-C6 carboxyl and C0-C6 alkylamine; r₅、R₆Independently selected from alkyl of C1-C6, alkoxy of C1-C6, alkyl halide of C1-C6,

Provided that R is₅、R₆At least one of them is

Wherein n is an integer from 4 to 7, representing a linking site; x: y is 3:7 to 7: 3.

Further, n is selected from 4,5,6,7, preferably 5.

Furthermore, the number average molecular weight of the polyaryletherketone single ion polymer is 30000-50000g/mol, preferably 35000-42000 g/mol.

Further, examples of the C1-C6 alkyl group are methyl, ethyl, propyl, butyl, pentyl, hexyl; examples of the alkyl halide of C1-C6 include, but are not limited to, trifluoromethyl, trichloromethyl; examples of the C1-C6 carboxylic acids include, but are not limited to, formate, acetate, propionate; the alkoxy group of C1-C6 includes but is not limited to methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy; the alkyl amine of C0-C6 includes but is not limited to amino, methylamino, ethylamino, propylamino, butylamino.

The second object of the present invention is to provide a method for preparing the above polyaryletherketone monoionic polymer, which comprises the following steps: dissolving allyl side group polyaryletherketone and lithium styrene sulfonyl (trifluoromethanesulfonyl) imide into an N, N-dimethylacetamide solution according to a molar ratio of 1: 0.5-3, adding an initiator, and carrying out a grafting reaction at 50-85 ℃ to obtain the polyaryletherketone single ion polymer.

The initiator is a radical polymerization initiator well known in the art, such as azobisisobutyronitrile, benzoyl peroxide, and the like.

Preferably, the molar ratio of the allyl side group polyaryletherketone to the lithium styrene sulfonyl (trifluoromethanesulfonyl) imide is 1: 0.6-2.

The allyl side group polyaryletherketone has a chemical structure of

R₁、R₂、R₃、R₄X, y are as defined above, R₇、R₈Independently selected from alkyl of C1-C6, alkoxy of C1-C6, alkyl halide of C1-C6, alkenyl of C2-C5; provided that R is₇、R₈At least one is selected from C2-C5 alkenyl.

In one embodiment of the present invention, R is₁，R₂Selected from trifluoromethyl, said R₃，R₄Selected from methyl, said R₇，R₈Selected from allyl, the allyl side group polyaryletherketone is obtained by a preparation method comprising the following steps：

Mixing hexafluorobisphenol A, 4 '-difluorobenzophenone and diallyl bisphenol A according to a molar ratio of 3-7: 10: 3-7, wherein the ratio of the total amount of the hexafluorobisphenol A and the diallyl bisphenol A to the amount of the 4,4' -difluorobenzophenone is 1:1-1.2, adding a catalyst, introducing nitrogen into a solvent and an azeotropic dehydrating agent, stirring, heating to 145-175 ℃ for reaction for 10 hours to obtain a viscous solution, adding distilled water into the viscous solution, cooling, crushing a product, washing with deionized water and ethanol, and drying to obtain the allyl side group polyaryletherketone.

The C2-C5 alkenyl groups have well-known meanings in the art and include, but are not limited to, ethenyl, propenyl, butenyl, pentenyl.

The catalyst is selected from sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and pyridine; the solvent is selected from N-methyl pyrrolidone, N-dimethylformamide, dimethyl sulfoxide or sulfolane; the azeotropic dehydrating agent is at least one of dimethylbenzene, chlorobenzene or toluene.

In the above preparation method, the lithium styrenesulfonyl (trifluoromethanesulfonyl) imide is obtained by a preparation method comprising the steps of:

(T1) stirring anhydrous acetonitrile, sodium p-styrenesulfonate and DMF (dimethyl formamide) under the nitrogen atmosphere to obtain a mixed solution, adding oxalyl chloride into the mixed solution for reaction, and filtering and removing the solvent to obtain a p-styrenesulfonyl chloride solution;

(T2) under the protection of nitrogen at 0 ℃, adding the p-styrenesulfonyl chloride and trifluoromethanesulfonimide obtained in the step (T1), 4-dimethylaminopyridine and triethylamine into acetonitrile, mixing and stirring, removing the solvent, adding dichloromethane, washing with a sodium bicarbonate aqueous solution and a hydrochloric acid solution respectively, removing the solvent, performing potassium ion exchange, filtering, and drying to obtain potassium styrenesulfonyl (trifluoromethanesulfonimide) imide;

(T3) in a glove box, lithium ion-exchanging the potassium styrenesulfonyl (trifluoromethanesulfonyl) imide obtained in the step (T2) in acetonitrile, filtering, and drying to obtain lithium styrenesulfonyl (trifluoromethanesulfonyl) imide LiSTFSI.

Further, in the step (T1), the molar ratio of the sodium p-styrene sulfonate, the DMF and the oxalyl chloride is 20-30:1-2: 25-35.

In the step (T2), the mol ratio of the p-styrene sulfonyl chloride to the trifluoromethanesulfonamide to the 4-dimethylaminopyridine to the triethylamine is 20-30:20-30:2-3: 80-90.

In one embodiment of the present invention, the polyaryletherketone monoionic polymer has the following structure represented by formula (I):

wherein x: y is 3:7 to 7: 3.

The synthesis route of the polyaryletherketone single ion polymer shown in the formula (I) is as follows:

the third purpose of the invention is to provide the application of the polyaryletherketone single ion polymer as a gel polymer electrolyte in a lithium battery.

The gel polymer electrolyte is prepared by a preparation method comprising the following steps:

(S1) dissolving the prepared polyaryletherketone single-ion polymer and a functional polymer in a solvent, wherein the polyaryletherketone single-ion polymer accounts for 45-65% of the total mass of the polyaryletherketone single-ion polymer and the functional polymer, filtering, casting on a plate, and forming a film at 45-160 ℃ for 10-30 h to obtain polyaryletherketone single-ion polymer electrolyte;

(S2) soaking the polyaryletherketone single-ion polymer electrolyte obtained in the step (1) in a plasticizer to obtain the polyaryletherketone single-ion gel polymer electrolyte.

The functional polymer in the step (S1) is at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyethylene oxide, polyoxypropylene, polyvinyl chloride, polyacrylonitrile, polymethyl methacrylate, or polyacrylonitrile-methyl methacrylate.

The solvent in the step (S1) is any one of N, N-dimethylacetamide, N-dimethylformamide, and N-methylpyrrolidone.

The plasticizer in the step (S2) is at least one of dimethyl carbonate (DMC), gamma-butyrolactone (GBL), Propylene Carbonate (PC), diethyl carbonate (DEC), Ethylene Carbonate (EC), and Ethyl Methyl Carbonate (EMC); the soaking time is 1-5 min.

Preferably, the plasticizer is a compound of ethylene carbonate/propylene carbonate with the volume ratio of 0.5-2:0.5-2, preferably 1-1.5: 1-1.5.

The invention adopts polyaryletherketone with a specific structure as a matrix to improve the thermal stability of a single-ion gel polymer electrolyte (SIGPE). In order to fix anions, lithium p-styrenesulfonyl (trifluoromethanesulfonyl) imide (LiSTFSI) is synthesized and then is subjected to free radical copolymerization with polyaryletherketone (APAEKx) with allyl side groups to obtain polyaryletherketone single ion polymer (APAEKx-LiSTFSI). The corresponding polyaryletherketone single ion gel polymer electrolyte (APAEKxSIGPE) is compounded by APAEKx-LiSTFSI and functional polymer. Because the lithium ion content in the prepared APAEKxSIGPE can be realized by adjusting the proportion of the APAEKx-LiSTFSI to the functional polymer, the ionic conductivity, the thermal stability and the like of the prepared single-ion gel polymer electrolyte can be obviously improved.

The preparation method of the gel polymer electrolyte based on the polyaryletherketone with a specific structure and the organic lithium salt has the following beneficial effects that:

(1) specific monomers are selected and prepared to obtain polyaryletherketone with a specific structure, and the polyaryletherketone is used as a matrix, so that the heat resistance of the electrolyte is effectively improved.

(2) The organic lithium salt of lithium styrene sulfonyl (trifluoromethanesulfonyl) imide (LiSTFSI) with high dissociation degree is prepared, so that lithium ions are more easily dissociated, and the lithium ions are grafted on the polyaryletherketone to fix anions on the polyaryletherketone substrate, so that only the lithium ions in a system move, and the electrochemical performance and the stability of the battery are improved. The prepared electrolyte material has excellent comprehensive performance, and the thermal stability and the electrochemical performance of the electrolyte material are optimized.

(3) The gel polymer electrolyte prepared by the invention has excellent electrochemical performance, the long-cycle stability of the assembled battery is good, and the capacity retention rate of the battery is more than 93% after 150 cycles of operation.

Drawings

FIG. 1 is APAEK prepared in preparations 1-3₃₀、APAEK₅₀、APAEK₇₀Is/are as follows¹HNMR atlas.

FIG. 2 is a graphic representation of potassium styrenesulfonyl (trifluoromethanesulfonyl) imide (KSTFSI) of preparation 4¹HNMR atlas.

FIG. 3 is APAEK prepared in preparations 1-3₃₀、APAEK₅₀、APAEK₇₀IR spectrum of (a).

FIG. 4 is an IR spectrum of potassium styrenesulfonyl (trifluoromethanesulfonyl) imide (KSTFSI) of preparation 4.

FIG. 5 is a polyaryletherketone monoionic gel polymer electrolyte (45% APAEK) of example 1₃₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 6 is the polyaryletherketone monoionic gel polymer electrolyte (55% APAEK) of example 2₃₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 7 shows a polyaryletherketone monoionic gel polymer electrolyte (65% APAEK) of example 3₃₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 8 is the polyaryletherketone monoionic gel polymer electrolyte (45% APAEK) of example 4₅₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 9 shows a polyaryletherketone monoionic gel polymer electrolyte (55% APAEK) of example 5₅₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 10 is the polyaryletherketone monoionic gel polymer electrolyte (65% APAEK) of example 6₅₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 11 is an example7 polyaryletherketone single ion gel polymer electrolyte (45% APAEK)₇₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 12 is a polyaryletherketone monoionic gel polymer electrolyte (55% APAEK) of example 8₇₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

FIG. 13 shows a polyaryletherketone monoionic gel polymer electrolyte (65% APAEK) of example 9₇₀SIGPE) electrochemical performance plot of assembled lithium ion batteries.

Detailed Description

The technical solution of the present invention is clearly and completely described below with reference to specific embodiments. Of course, the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

Preparation example 1

0.0084mol of hexafluorobisphenol A, 0.0036mol of diallyl bisphenol A, 0.012mol of 4,4' -difluorobenzophenone, 1.9872g of anhydrous potassium carbonate, 18mL of sulfolane (TMS) and 8mL of toluene are sequentially added into a three-neck flask provided with a mechanical stirrer, a nitrogen inlet pipe, a thermometer and a water separator, nitrogen is introduced into the flask and stirred, the temperature is raised to 145-175 ℃ to react for 10 hours to obtain viscous solution, then the viscous solution is added into distilled water, the product is crushed after cooling, and then washed by deionized water and ethanol and dried to obtain allyl side group polyaryletherketone APAEK-30.

Preparation example 2

The method and conditions are the same as those in preparation example 1, except that the monomers are used in amounts of 0.006mol of hexafluorobisphenol A, 0.006mol of diallyl bisphenol A and 0.012mol of 4,4' -difluorobenzophenone, and finally the allyl side group polyaryletherketone APAEK-50 is obtained.

Preparation example 3

The method and conditions are the same as those of preparation example 1, except that the monomer dosage is 0.0036mol of hexafluorobisphenol A, 0.0084mol of diallyl bisphenol A and 0.012mol of 4,4' -difluorobenzophenone, and finally the allyl side group polyaryletherketone APAEK-70 is obtained.

Preparation example 4

(1) Stirring 60mL of anhydrous acetonitrile, 0.029mol of sodium p-styrenesulfonate and 0.0015mol of DMF (dimethyl formamide) under the nitrogen atmosphere to obtain a mixed solution, adding 0.035mol of oxalyl chloride into the mixed solution to react for 24 hours, and filtering and removing the solvent to obtain a p-styrenesulfonyl chloride solution;

(2) adding 29.1mmol of trifluoromethanesulfonamide, 2.58mmol of DMAP, 0.087mol of triethylamine and 50mL of acetonitrile into a three-necked flask under nitrogen atmosphere, stirring to obtain a mixed solution, adding 29.1mmol of p-styrenesulfonyl chloride obtained in the step (1) into the mixed solution at 0 ℃, stirring for 20h, removing the solvent, adding dichloromethane, washing with a sodium bicarbonate aqueous solution and a hydrochloric acid solution respectively, removing the solvent, performing potassium ion exchange, filtering, and drying to obtain potassium styrenesulfonyl (trifluoromethanesulfonyl) imide.

(3) And (3) in a glove box, performing lithium ion exchange on the potassium styrenesulfonyl (trifluoromethanesulfonyl) imide obtained in the step (2) in acetonitrile, filtering and drying to obtain the lithium styrenesulfonyl (trifluoromethanesulfonyl) imide LiSTFSI.

Preparation example 5

3.84mmol of APAEK-30, 2.76mmol of LiSTFSI, 0.91mg of AIBN and 6mL of DMAc are put into a three-neck flask connected with double calandria, the system is deoxidized by three times of freezing-pumping-unfreezing cycles, and then the reaction is carried out for 24 hours in an oil bath at the temperature of 55 ℃. After the reaction is finished, precipitating by using ethanol, washing by using the ethanol for three times, and carrying out vacuum drying for 24 hours at the temperature of 100 ℃. So as to obtain the product polyaryletherketone single ion polymer APAEK₃₀-LiSTFSI。

Preparation example 6

3.84mmol of APAEK-50, 4.61mmol of LiSTFSI, 1.51mg of AIBN and 7mL of DMAc are put into a three-neck flask connected with double calandria, the system is deoxidized by three freezing-pumping-unfreezing cycles, and then the reaction is carried out for 24 hours in an oil bath at the temperature of 55 ℃. After the reaction is finished, precipitating by using ethanol, washing by using the ethanol for three times, and carrying out vacuum drying for 24 hours at the temperature of 100 ℃. So as to obtain the product polyaryletherketone single ion polymer APAEK₅₀-LiSTFSI。

Preparation example 7

3.84mmol of APAEK-70, 6.45mmol of LiSTFSI, 2.12mg of AIBN and 9mLDMAc is put into a three-neck flask connected with a double-calandria, the system is deoxidized through three times of freezing-pumping-unfreezing circulation, and then the reaction is carried out for 24 hours in an oil bath at the temperature of 55 ℃. After the reaction is finished, precipitating by using ethanol, washing by using the ethanol for three times, and carrying out vacuum drying for 24 hours at the temperature of 100 ℃. So as to obtain the product polyaryletherketone single ion polymer APAEK₇₀-LiSTFSI。

Example 1

Adding 0.108g of APAEK₃₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.132g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain the polyaryletherketone single-ion gel polymer electrolyte of 45 percent of APAEK₃₀SIGPE。

Example 2

Adding 0.132g of APAEK₃₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.108g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain 55% APAEK of the polyaryletherketone single-ion gel polymer electrolyte₃₀SIGPE。

Example 3

Adding 0.156g of APAEK₃₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.084g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain the polyaryletherketone single-ion gel polymer electrolyte of 65 percent APAEK₃₀SIGPE。

Example 4

Adding 0.108g of APAEK₅₀LiSTFSI dissolved in 3.6mL of NMPDissolving in solvent by ultrasonic wave. Adding 0.132g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain the polyaryletherketone single-ion gel polymer electrolyte of 45 percent of APAEK₅₀SIGPE。

Example 5

Adding 0.132g of APAEK₅₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.108g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain 55% APAEK of the polyaryletherketone single-ion gel polymer electrolyte₅₀SIGPE。

Example 6

Adding 0.156g of APAEK₅₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.084g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain the polyaryletherketone single-ion gel polymer electrolyte of 65 percent APAEK₅₀SIGPE。

Example 7

Adding 0.108g of APAEK₇₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.132g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain the polyaryletherketone single-ion gel polymer electrolyte of 45 percent of APAEK₇₀SIGP。

Example 8

Adding 0.132g of APAEK₇₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.108g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain 55% APAEK of the polyaryletherketone single-ion gel polymer electrolyte₇₀SIGPE。

Example 9

Adding 0.156g of APAEK₇₀LiSTFSI was dissolved in 3.6mL of NMP solvent and sonicated to dissolve. Adding 0.084g of PEO after the PEO is completely dissolved, performing ultrasonic treatment, filtering impurities by using 400-mesh filter cloth after the polymer is completely dissolved and uniformly dispersed, casting the mixture on a clean glass plate, performing vacuum drying at 80 ℃ for 12h to form a film to obtain the polyaryletherketone single-ion polymer electrolyte, soaking the polyaryletherketone single-ion gel polymer electrolyte in EC/PC (v/v, 1:1) for 2min to obtain the polyaryletherketone single-ion gel polymer electrolyte of 65 percent APAEK₇₀SIGPE。

1. Characterization analysis

Structural analysis of allyl pendant polyaryletherketone APAEK-30 of preparation 1, allyl pendant polyaryletherketone APAEK-50 of preparation 2, allyl pendant polyaryletherketone APAEK-70 of preparation 3, and lithium styrene sulfonyl (trifluoromethanesulfonyl) imide of preparation 4:

FIG. 1 is APAEK prepared in preparations 1-3₃₀、APAEK₅₀、APAEK₇₀Is/are as follows¹HNMR atlas. It can be seen that the nuclear magnetic characterization results of the allyl side group polyaryletherketone and lithium styrenesulfonyl (trifluoromethanesulfonyl) imide are as follows: using CDCl₃Dissolving allyl side group polyaryletherketone, and detecting the structure of the polyaryletherketone by a nuclear magnetic hydrogen spectrum, wherein the result is shown in the attached figure 1: the peaks at chemical shifts between 1.62 and 1.20ppm correspond to the hydrogen atoms on the allyl groups confirming the presence of an alkenyl propane with chemical shifts at 7.85 to 7.75ppm, 7.45 to 7.19ppm and 7.11 to 6.87ppm with the hydrogen peaks on the three groups of aromatic rings. Due to the electron withdrawing effect of the carbonyl group, the hydrogen displacement adjacent to the carbonyl group moves to a low field; and due to the electron-donating effect of the oxygen atom,the hydrogen adjacent to oxygen will move towards high field, so there are three different groups of aromatic hydrogen shifts, thus proving the functional group structure of allyl side group polyaryletherketone.

FIG. 2 is a graphic representation of potassium styrenesulfonyl (trifluoromethanesulfonyl) imide (KSTFSI) of preparation 4¹HNMR atlas. By d₆-DMSO dissolves lithium styrenesulfonyl (trifluoromethanesulfonyl) imide, and the structure is detected by nuclear magnetic hydrogen spectroscopy, and the result is shown in the attached figure 2: chemical shifts 5.38ppm, 5.95ppm, and 6.78ppm respectively correspond to hydrogen atoms on the vinyl group; chemical shifts 7.57ppm and 7.71ppm respectively correspond to hydrogen atoms on a benzene ring, and the functional group structure of the lithium styrenesulfonyl (trifluoromethanesulfonyl) imide LiSTFSI is proved.

FIG. 3 is APAEK prepared in preparations 1-3₃₀、APAEK₅₀、APAEK₇₀IR spectrum of (a). The infrared characterization result of the allyl side group polyaryletherketone is shown in figure 3: 1174cm^-1And 1208cm^-1Corresponds to-CF₃Absorption peak of (4); 1655cm^-1Corresponding to the telescopic absorption peak of carbonyl; 1594cm^-1And 1498cm^-1Is located at 835cm which is a characteristic peak of vibration in a benzene ring plane^-1The position is an absorption peak substituted by a benzene ring at the para position; 1016cm^-1And 1243cm^-1Absorption peak of symmetric and asymmetric stretching vibration corresponding to ether bond, 990cm^-1Characteristic absorption peak of allyl group.

FIG. 4 is an IR spectrum of potassium styrenesulfonyl (trifluoromethanesulfonyl) imide (KSTFSI) of preparation 4. The infrared characterization of lithium styrenesulfonyl (trifluoromethanesulfonyl) imide is shown in fig. 4: 1174cm^-1And 1208cm^-1Corresponds to-CF₃Absorption peak of (4); 1594cm^-1And 1498cm^-1The position is a characteristic peak of vibration in a benzene ring plane; 1330cm^-1And 1140cm^-1And the symmetric stretching vibration peak and the asymmetric stretching vibration peak correspond to O-S-O.

2. Analysis of thermal stability

Table 1 shows the thermal stability test data of APAEK-30, APAEK-50 and APAEK-70 prepared in preparation examples 1-3.

TABLE 1

Sample (I)	T_d5(℃)	T_d10(℃)
			Preparation example 1	485	510
Preparation example 2	473	489
			Preparation example 3	462	478

Table 2 shows APAEK prepared in preparation examples 5 to 7₃₀-LiSTFSI、APAEK₅₀LiSTFSI and APAEK₇₀Thermal stability test data of LiSTFSI.

TABLE 2

Sample (I)	T_d5(℃)	T_d10(℃)
			Preparation example 5	397	422
Preparation example 6	375	408
			Preparation example 7	345	371

T_d5And T_d10The temperatures at 5% and 10% weight loss, respectively, are indicated.

It can be seen that 5% and 10% of thermal weight loss temperatures of the allyl side group polyaryletherketone and the polyaryletherketone single ion polymer prepared by the invention are respectively higher than 340 ℃, which shows that the allyl side group polyaryletherketone and the polyaryletherketone single ion polymer have good thermal stability.

Application exampleProperties of polyaryletherketone single ion gel polymer electrolyte

(1) Morphology characterization of polyaryletherketone single-ion gel polymer electrolyte

The polyaryletherketone single ion gel polymer electrolytes of examples 1-9 have smooth surfaces, no cracks and transparent films, thereby showing that the gel polymer electrolytes prepared by the invention have excellent compatibility.

(2) Dimensional stability test of polyaryletherketone single ion gel polymer electrolyte

The polyaryletherketone single ion gel polymer electrolyte obtained in the embodiments 1-9 of the invention is cut into 2 x 2cm squares, then placed in an oven at 150 ℃ for heating for 30min, and after being taken out, the size and the shape of the wafer are observed and recorded. The results are shown in Table 3: due to the good thermal stability of the polyaryletherketone and the important matrix skeleton effect thereof, the polyaryletherketone single ion gel polymer electrolyte of the embodiments 1-9 has the dimensional shrinkage lower than 8%, shows good thermal dimensional stability, and can effectively ensure the safety of the battery at high temperature.

TABLE 3

Sample (I)	Dimensional shrinkage (%)
		Example 1	7.1
Example 2	6.6
		Example 3	6.3
Example 4	7.4
		Example 5	6.9
Example 6	6.5
		Example 7	7.7
Example 8	7.3
		Example 9	7.1

(3) Examples 1-9 polyaryletherketone single ion gel polymer electrolyte ionic conductivity and lithium ion transport number tests

Ionic conductivity: constructing a blocking electrode of stainless steel/electrolyte/stainless steel structure, measuring the impedance thereof by using an electrochemical workstation, and adopting the formula: sigma-L/SR_bCalculating the ionic conductivity, wherein σ is the ionic conductivity of the electrolyte, L is the thickness of the electrolyte, S is the area of the electrolyte, R_bIs the resistance of the electrolyte at room temperature.

Transference number of lithium ion: an electrode of a lithium sheet/electrolyte/lithium sheet structure is constructed, steady-state current method measurement is carried out through an electrochemical workstation, the polarization voltage is 10mV, the frequency range is 1 MHz-100 Hz, impedance before and after a lithium electrode passivation layer is formed is measured, and a formula is adopted: t is t⁺＝I_s(△V–I_oR_o)/I_o(△V–I_sR_s) Calculating the transference number of lithium ions, wherein △ V is given polarization voltage, I_oAnd I_sRespectively the initial current and the steady-state current before and after passivation, R_oAnd R_sThe interfacial impedance of the cell before and after the reaction, respectively.

As shown in Table 4, the thermal stability of the single ion gel polymer electrolytes obtained in examples 1-3 was better, while the conductivity of the polyaryletherketone single ion gel polymer electrolytes described in examples 4-9 was higher, i.e., 5.9 × 10 or more was 5.9 ×^-4S cm^-1And the transference number of lithium ions is more than or equal to 0.94, so that the single-ion gel polymer electrolyte has better application prospect.

TABLE 4

(4) Battery Performance testing of polyaryletherketone Mono-ion gel Polymer electrolytes of examples 1-9

Testing electrical properties includes the following steps:

preparing a positive plate: mixing LiFePO₄Polyvinylidene fluorideDissolving ethylene and acetylene black in N-methyl pyrrolidone in a mass ratio of 8:1:1, and uniformly mixing. And (3) scraping the slurry on an aluminum foil by using a scraper, drying, rolling, cutting into pieces, weighing and drying in vacuum.

Assembling the battery: and placing the positive plate, the polyaryletherketone single-ion gel polymer electrolyte and the metal lithium plate in a battery shell, and then packaging.

And (3) testing the electrical property of the battery: testing the charge-discharge performance of the battery by using a battery performance testing cycle tester (BTS-4000), wherein the test conditions are as follows: 25 ℃ and 0.2C.

The results are shown in FIGS. 5-13: as can be seen, in example 1, 45% APAEK₃₀Under the condition of 156 cycles of circulation, the specific discharge capacity of the SIGPE is kept at 97mAh g^-1The coulombic efficiency can be kept at 101%, and the capacity retention rate is 100%; in example 2, 55% APAEK₃₀Under the condition of 163 cycles of the SIGPE, the specific discharge capacity is kept at 100mAh g^-1The coulombic efficiency can be kept at 98%, and the capacity retention rate is 98.8%; in example 3, 65% APAEK₃₀The discharge capacity of the SIGPE is kept at 101mAh g under the condition of 154 cycles^-1The coulombic efficiency can be kept about 100%, and the capacity retention rate is 99.2%; in example 4, 45% APAEK₅₀Under the condition of 159 cycles of the SIGPE, the specific discharge capacity is kept at 114mAhg^-1The coulombic efficiency can be kept about 100%, and the capacity retention rate is 99.4%; in example 5, 55% APAEK₅₀Under the condition of 151 cycles of the SIGPE, the specific discharge capacity is kept at 112mAh g^-1The coulombic efficiency can be kept at about 97%, and the capacity retention rate is 94.2%; in example 6, 65% APAEK₅₀The specific discharge capacity of the SIGPE is kept at 127mAh g under the condition of circulating 154 circles^-1The coulombic efficiency can be kept at 98%, and the capacity retention rate is 97.3%; in example 7, 45% APAEK₇₀Under the condition of 222 cycles of the SIGPE, the specific discharge capacity is kept at 139mAh g^-1The coulombic efficiency can be kept at 101%, and the capacity retention rate is 98.6%; in example 8, 55% APAEK₇₀Under the condition of 160 cycles of the SIGPE, the specific discharge capacity is kept at 146mAh g^-1Coulombic efficiencyCan be kept at 101%, and the capacity retention rate is 98.5%; in example 9, 65% APAEK₇₀The specific discharge capacity of the SIGPE is maintained at 154mAh g under the condition of 152 cycles of circulation^-1The coulombic efficiency can be kept at 101%, and the capacity retention rate is 99.2%. It can be seen that the battery assembled by the single-ion gel polymer electrolyte has high discharge specific capacity and stable cycle efficiency.

The gel polymer electrolyte provided by the invention has good specific discharge capacity and high coulombic efficiency, and is attributed to the structure and composition thereof, the special structure of styrene sulfonyl (trifluoromethanesulfonyl) imide lithium in the single-ion polymer, wherein the electron delocalization of nitrogen atoms is realized by-SO with strong electron-withdrawing capability₂-N^(-)-SO₂-CF₃The groups are enhanced by a para-position synergistic effect with the benzene ring, so that Li⁺More readily dissociates and provides a source of lithium. By addition of PEO, in which the ether oxygen bond can be bound to Li⁺Complexation, in turn, promotes Li⁺Conduction of (3). The above structure and composition contribute to good electrochemical performance of the electrolyte.

In addition, in order to verify that the gel polymer electrolyte provided by the present invention has satisfactory electrochemical properties at higher temperatures, the cells were assembled in the same manner as described above, and the electrochemical properties of the cells at 50 ℃, 0.2 ℃ were tested, with the results shown in table 5 below:

TABLE 5

It can be seen that the battery assembled with the gel polymer electrolyte provided by the present invention has excellent long cycle stability and safety at 50 ℃, further highlighting the advantages of the present invention.

In conclusion, the lithium ion battery assembled by the polyaryletherketone single-ion gel polymer electrolyte prepared by the invention has good lithium ion conductivity and stable battery performance, and has good commercial popularization prospect.

Claims

1. A polyaryletherketone monoionic polymer having a formula of formula (II):

wherein R is₁、R₂、R₃、R₄Independently selected from C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkyl halide, C1-C6 carboxyl and C0-C6 amine; r₅、R₆Independently selected from alkyl of C1-C6, alkoxy of C1-C6, alkyl halide of C1-C6,

Provided that R is₅、R₆At least one of them is

2. The polyaryletherketone monoionic polymer of claim 1, wherein the polyaryletherketone monoionic polymer has a number average molecular weight of 30000-50000g/mol, preferably of 35000-42000 g/mol.

3. The polyaryletherketone monoionic polymer of claim 1 wherein said C1-C6 alkyl is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl; the alkyl halide of C1-C6 is selected from trifluoromethyl and trichloromethyl; the carboxylic acid of C1-C6 is selected from formate, acetate and propionate; the alkoxy of C1-C6 is selected from methoxy, ethoxy, propoxy, butoxy, pentoxy and hexoxy; the amine of C0-C6 is selected from amino, methylamino, ethylamino, propylamino and butylamino.

4. The polyaryletherketone monoionic polymer of claim 1 having the following structural formula (I):

5. a process for the preparation of a polyaryletherketone monoionic polymer as claimed in any one of claims 1 to 4, comprising the steps of: dissolving allyl side group polyaryletherketone and lithium styrene sulfonyl (trifluoromethanesulfonyl) imide into an N, N-dimethylacetamide solution according to a molar ratio of 1: 0.5-3, adding an initiator, and carrying out a grafting reaction at 50-85 ℃ to obtain a polyaryletherketone single ion polymer;

the allyl side group polyaryletherketone has the chemical structure as follows:

wherein R is₇、R₈Independently selected from alkyl of C1-C6, alkoxy of C1-C6, alkyl halide of C1-C6, alkenyl of C2-C5; provided that R is₇、R₈At least one is selected from C2-C5 alkenyl.

6. The method of claim 5, wherein the molar ratio of the allyl pendant poly (aryl ether ketone) to the lithium styrene sulfonyl (trifluoromethanesulfonyl) imide is 1: 0.6-2.

7. The method of claim 5, wherein said pendant allyl polyaryletherketone is prepared by a method comprising the steps of: mixing hexafluorobisphenol A, 4 '-difluorobenzophenone and diallyl bisphenol A according to a molar ratio of 3-7: 10: 3-7, wherein the ratio of the total amount of the hexafluorobisphenol A and the diallyl bisphenol A to the amount of the 4,4' -difluorobenzophenone is 1:1-1.2, adding a catalyst, introducing nitrogen into a solvent and an azeotropic dehydrating agent, stirring, heating to 145-175 ℃, reacting for 10 hours to obtain a viscous solution, and performing post-treatment to obtain the allyl side group polyaryletherketone.

8. The process for preparing the polyaryletherketone monoionic polymer of formula (I) as claimed in claim 4, wherein the synthesis route is as follows:

9. use of the polyaryletherketone monoionic polymer of any of claims 1-4 as a gel polymer electrolyte in a lithium battery.

10. The use of claim 9, wherein the gel polymer electrolyte is prepared by a preparation method comprising the steps of:

(S1) dissolving the prepared polyaryletherketone single-ion polymer and a functional polymer in a solvent, wherein the polyaryletherketone single-ion polymer accounts for 45-65% of the total mass of the polyaryletherketone single-ion polymer and the functional polymer, and forming a film to obtain a polyaryletherketone single-ion polymer electrolyte;

(S2) soaking the polyaryletherketone single ion polymer electrolyte obtained in the step (S1) in a plasticizer to obtain the polyaryletherketone single ion gel polymer electrolyte.