Gel polymer electrolyte composition, gel polymer electrolyte, battery monomer and preparation method thereof, and electric device

Abstract

The invention discloses a gel polymer electrolyte composition, a gel polymer electrolyte, a battery monomer and a preparation method thereof, and an electric device. The gel polymer electrolyte composition comprises a non-aqueous electrolyte, a monomer as shown in a formula I and a polymer as shown in a formula II. When the gel polymer electrolyte composition is used in a battery monomer, the cycle life and the storage life of the battery monomer can be prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to a gel polymer electrolyte composition, a gel polymer electrolyte, a battery cell and a preparation method thereof, and an electric device. BACKGROUND

[0002] Lithium metal battery cells using lithium metal as the negative electrode have much higher mass and volume energy densities than lithium-ion battery cells, which are critical for the implementation of high-range electric vehicles, drones, electric aircraft, and other application scenarios. However, compared with lithium-ion battery cells, lithium metal battery cells have poor cycle life and storage life. SUMMARY

[0003] The present application provides a gel polymer electrolyte composition, a gel polymer electrolyte, a battery cell and a preparation method thereof, and an electric device, the gel polymer electrolyte composition is used in the battery cell, which can improve the cycle life and storage life of the battery cell.

[0004] In a first aspect, the present application provides a gel polymer electrolyte composition, comprising: a non-aqueous electrolyte, a monomer represented by formula I, and a polymer represented by formula II.

[0005]

[0006] R1, R2, R3, R4, R5, R6, N of which are active groups, and the N active groups are independently selected from any one of vinyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine, amine-substituted C1-C5 alkyl, thiol, thiol-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, methacrylate, and the remaining (6-N) are independently selected from any one of H, C1-C5 alkyl, C1-C5 haloalkyl, C1-C5 oxaalkyl, N is 3, 4, 5 or 6; R7 and R8 are independently selected from any one of vinyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine, amine-substituted C1-C5 alkyl, thiol, thiol-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, methacrylate, and R7 and R8 can be polymerized with the N active groups in R1, R2, R3, R4, R5, R6; M1, M2, M3, M4, M5, M6 are independently selected from any one of H, halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine, amine-substituted C1-C5 alkyl, C1-C5 alkyl, C1-C5 oxaalkyl at each occurrence, and at least one of M1, M2, M3, M4, M5, M6 is selected from any one of halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine, amine-substituted C1-C5 alkyl; n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n x m is 10-10000.

[0007] The gel polymer electrolyte composition provided by the embodiments of the present application comprises monomers represented by Formula I and polymers represented by Formula II, the monomers represented by Formula I and the polymers represented by Formula II can be polymerized, and thus the gel polymer electrolyte can be formed after polymerization. The polymer backbone of the gel polymer electrolyte is formed after the monomers represented by Formula I and the polymers represented by Formula II are polymerized. The gel polymer electrolyte is flexible and can have good contact with the electrode interface, thereby reducing the interface impedance.

[0008] The monomer shown in formula I and the polymer shown in formula II have a benzene ring, the benzene ring has rigidity, and at the same time has a large pi bond structure, which can improve the strength of the gel polymer electrolyte. The polymer shown in formula II also has an ether oxygen segment, the ether oxygen segment has flexibility, so that the polymer skeleton network formed has both rigidity and flexibility, so that the gel polymer electrolyte can maintain good contact with the electrode interface under the continuous expansion and contraction of the battery monomer during cyclic charging and discharging, and at the same time, the gel polymer electrolyte is not prone to breakage, thereby enabling the battery monomer to have a long cycle life and storage life. The polymer shown in formula II has an ether oxygen segment, which has good affinity for the non-aqueous electrolyte, so that the non-aqueous electrolyte is bound in the polymer skeleton network, so that it cannot flow freely. In this way, on the one hand, it can reduce the side reaction of the unstable organic solvent and lithium salt anion in the non-aqueous electrolyte continuously consuming active lithium on the negative electrode interface, and on the other hand, it is also conducive to the long-term stable infiltration of the non-aqueous electrolyte into the electrode assembly, reducing the occurrence of local dryness, thereby improving the cycle life of the battery monomer.

[0009] At least one of M1, M2, M3, M4, M5, and M6 in the polymer shown in formula II is selected from any one of a halogen atom, a C1-C5 halogenated alkyl group, a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, and an amine-substituted C1-C5 alkyl group. These groups can form a strong hydrogen bond interaction with the organic solvent and the lithium salt anion in the non-aqueous electrolyte, and through the hydrogen bond interaction, the organic solvent and the lithium salt anion can be anchored, so that they cannot migrate to the lithium metal negative electrode interface at will to consume active lithium.

[0010] n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n x m is 10-10000, so that the polymer skeleton network formed has both rigidity and flexibility, so that the gel polymer electrolyte can maintain good contact with the electrode interface under the continuous expansion and contraction of the battery monomer during cyclic charging and discharging, and at the same time, the gel polymer electrolyte is not prone to breakage, thereby enabling the battery monomer to have a long cycle life and storage life.

[0011] Therefore, the gel polymer electrolyte composition provided by the embodiments of the present application is used in the battery monomer, which can reduce the interface side reaction and improve the cycle life and storage life of the battery monomer.

[0012] In some embodiments, n is an integer between 2 and 400. In this way, the polymer shown in formula II has both flexibility and a suitable ratio of ether oxygen segment to benzene ring, so that the gel polymer electrolyte has good mechanical properties.

[0013] In some embodiments, m is an integer between 5 and 800. In this way, the formed gel polymer electrolyte can have a more suitable skeleton space, so that the gel polymer electrolyte can fully accommodate the non-aqueous electrolyte even in the case of a lower polymer skeleton mass fraction, and good ion transmission characteristics can be achieved.

[0014] In some embodiments, n x m is 100-4000. In this way, the battery cell can have a longer cycle life and storage life.

[0015] In some embodiments, the weight average molecular weight of the polymer represented by formula II is 7500-360,000. In this way, the battery cell can have a longer cycle life and storage life.

[0016] In some embodiments, the polymerization reaction of R7 and R8 with N active groups in R1, R2, R3, R4, R5, R6 includes a condensation polymerization reaction, an addition polymerization reaction.

[0017] In some embodiments, the N active groups in R1, R2, R3, R4, R5, R6 are the same.

[0018] In some embodiments, R7 and R8 are the same.

[0019] In some embodiments, the N active groups in R1, R2, R3, R4, R5, R6 are selected from any one of a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, and an amine-substituted C1-C5 alkyl group, and R7 and R8 are selected from any one of an isocyanate group and a methylene isocyanate group.

[0020] In some embodiments, the N active groups in R1, R2, R3, R4, R5, R6 are each independently selected from any one of an isocyanate group and a methylene isocyanate group, and R7 and R8 are selected from any one of a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, and an amine-substituted C1-C5 alkyl group.

[0021] In some embodiments, the N active groups in R1, R2, R3, R4, R5, R6 are selected from a vinyl group, and R7 and R8 are selected from any one of a vinyl group, an acrylate group, a methacrylate group, a mercapto group, and a mercapto-substituted C1-C5 alkyl group.

[0022] In some embodiments, the N active groups in R1, R2, R3, R4, R5, R6 are selected from any one of a mercapto group and a mercapto-substituted C1-C5 alkyl group, and R7 and R8 are selected from a vinyl group.

[0023] In some embodiments, N of R1, R2, R3, R4, R5, R6 is independently selected from any one of acrylate group, methacrylate group, and R7 and R8 are selected from any one of vinyl group, acrylate group, methacrylate group.

[0024] In some embodiments, N is 3, and R1, R3, R5 are active groups.

[0025] In some embodiments, the monomer of formula I is selected from any one of the following:

[0026]

[0027]

[0028] In some embodiments, one or two of M1, M2, M3, M4, M5, M6 are selected from any one of halogen atom, C1-C5 haloalkyl, hydroxyl group, hydroxyl-substituted C1-C5 alkyl, amine group, amine-substituted C1-C5 alkyl.

[0029] In some embodiments, the polymer of formula II is selected from any one of the following:

[0030]

[0031]

[0032] In some embodiments, the molar ratio of the monomer of formula I to the polymer of formula II is 2:N. This can allow the end groups of the monomer of formula I and the polymer of formula II to match and react.

[0033] In some embodiments, the total mass fraction of the monomer of formula I and the polymer of formula II is 0.5%-20% based on the total mass of the gel polymer electrolyte composition.

[0034] In some embodiments, the gel polymer electrolyte composition further comprises an initiator.

[0035] In a second aspect, the present application provides a gel polymer electrolyte, which is obtained by polymerizing the gel polymer electrolyte composition of the first aspect of the present application.

[0036] In a third aspect, the present application provides a battery cell comprising a gel polymer electrolyte, which is obtained by polymerizing the gel polymer electrolyte composition of the first aspect of the present application.

[0037] The battery cell comprises a gel polymer electrolyte obtained by polymerizing the gel polymer electrolyte composition of the first aspect of the present application, and thus can have a longer cycle life and storage life.

[0038] In some embodiments, the method for polymerizing the gel polymer electrolyte composition of the first aspect of this application is in-situ curing polymerization.

[0039] Fourthly, this application provides a method for preparing a battery cell, comprising the following steps: providing a battery cell to be injected with electrolyte, mixing the gel polymer electrolyte composition of the first aspect of this application to obtain a precursor solution, injecting the obtained precursor solution into the battery cell to be injected with electrolyte, and then treating under heating conditions to allow the precursor solution to solidify and polymerize in situ inside the battery cell to form a gel polymer electrolyte, thereby obtaining the battery cell.

[0040] Fifthly, this application provides a battery, including a battery cell according to the third aspect of this application or a battery cell prepared by the preparation method according to the fourth aspect of this application.

[0041] Sixthly, this application provides an electrical device including a battery cell according to the fifth aspect of this application. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of one embodiment of the battery cell of this application.

[0044] Figure 2 This is an exploded view of one embodiment of the battery cell of this application.

[0045] Figure 3 This is a schematic diagram of one embodiment of the battery module of this application.

[0046] Figure 4 This is a schematic diagram of one embodiment of the battery pack of this application.

[0047] Figure 5 yes Figure 4 An exploded view of an embodiment of the battery pack shown.

[0048] Figure 6 This is a schematic diagram of one embodiment of an electrical device that uses the battery of this application as a power source.

[0049] The accompanying drawings are not necessarily drawn to scale. The reference numerals are explained as follows: 1 Battery pack, 2 Upper casing, 3 Lower casing, 4 Battery module, 5 Individual battery cell, 51 Housing, 52 Electrode assembly, 53 Cover plate. DETAILED DESCRIPTION

[0050] Hereinafter, specific embodiments of the gel polymer electrolyte composition, the gel polymer electrolyte, the battery cell and the method for manufacturing the same, and the electric device of the present application will be explained in detail with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed explanation is omitted. For example, there will be cases where detailed explanation of matters known well, repeated explanation of substantially identical structures are omitted. This is to avoid the following explanation from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the accompanying drawings and the following explanation are provided so that those skilled in the art can fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0051] The ranges disclosed herein are defined by the lower and upper limits in the form of a range, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The ranges defined in this manner can include the end values or not, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges of 60-110 and 80-120 are also contemplated. In addition, if the minimum range values of 1 and 2 are listed, and if the maximum range values of 3, 4, and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present application, unless otherwise specified, the numerical range "a-b" represents a shorthand notation for any real combination of integers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is just a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0052] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0053] If not specifically stated, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0054] If not otherwise specified, all steps of the present application can be carried out in sequence or randomly, preferably in sequence. For example, the method comprising steps (a) and (b) means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method further comprising step (c) means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0055] Unless otherwise specified, the terms used in the present application have the meanings commonly understood by a person skilled in the art.

[0056] Unless otherwise specified, the values of the parameters mentioned in the present application can be measured by various test methods commonly used in the art, for example, by the test methods given in the examples of the present application. Unless otherwise specified, the test temperature of each parameter is 25°C.

[0057] The battery mentioned in the examples of the present application can comprise one or more battery cells to provide a single physical module with higher voltage and capacity. For example, the battery mentioned in the present application can comprise a battery cell, a battery module or a battery pack, etc.

[0058] The battery cell is the smallest unit that constitutes a battery, which can realize the function of charging and discharging by itself. The battery cell can be in the shape of a cylinder, a cuboid or other shapes, which are not limited in the examples of the present application. For example, Figure 1 is a battery cell 5 in the shape of a cuboid as an example.

[0059] When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in a mixed manner by a busbar. In some examples, the battery can be a battery module; when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. In some examples, the battery can be a battery pack, which comprises a box and battery cells, and the battery cells or the battery module are contained in the box. In some examples, the box can be part of the chassis structure of the vehicle. For example, part of the box can be at least part of the floor of the vehicle, or part of the box can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0060] In some examples, the battery can be an energy storage device. The energy storage device comprises an energy storage container, an energy storage cabinet, etc.

[0061] The battery cell comprises an electrode assembly. The electrode assembly can be in a jelly-roll structure or in a stacked structure, which are not limited in the examples of the present application.

[0062] The battery cell can further include an outer package, which can be used to encapsulate the electrode assembly and the non-aqueous electrolyte. The outer package can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package can also be a soft package, such as a pouch-type soft package. The soft package can be made of plastic, such as one or more of aluminum-plastic film, polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0063] In some embodiments, as shown in FIG. 1, the outer package can include a housing 51 and a cover plate 53. The housing 51 can include a bottom plate and side plates connected to the bottom plate, which enclose a receiving cavity. The housing 51 has an opening in communication with the receiving cavity, and the cover plate 53 is used to cover the opening to close the receiving cavity. The electrode assembly 52 is encapsulated in the receiving cavity. The number of electrode assemblies 52 included in the battery cell 5 can be one or more, which can be adjusted according to requirements. Figure 2

[0064] In some embodiments, the battery cell can be assembled into a battery module, and the number of battery cells included in the battery module can be multiple, which can be adjusted according to the application and capacity of the battery module. Figure 3 FIG. 1 is a schematic view of a battery module 4 as an example. As shown in FIG. 1, in the battery module 4, a plurality of battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, other arbitrary arrangements can also be used. Further, the plurality of battery cells 5 can be fixed by fasteners. Figure 3

[0065] Optionally, the battery module 4 can further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0066] In some embodiments, the above-mentioned battery module can also be assembled into a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0067] Figure 4 FIG. 2 is a schematic view of a battery pack 1 as an example. As shown in FIG. 2, in the battery pack 1, a plurality of battery modules 4 can be arranged in the box body in an arbitrary manner. Figure 5 Figure 4 Figure 5 As shown in FIG. 2, in the battery pack 1, a box body and a plurality of battery modules 4 arranged in the box body can be included. The box body includes an upper box body 2 and a lower box body 3, and the upper box body 2 is used to cover the lower box body 3 and form a closed space for receiving the battery modules 4. The plurality of battery modules 4 can be arranged in the box body in an arbitrary manner.

[0068] ​​​​The insufficient cycle life and storage life of lithium metal battery cells are mainly caused by the serious interface side reactions, which continuously consume the organic solvent and lithium salt anion in the non-aqueous electrolyte, and also continuously consume the active lithium. In addition, the conventional non-aqueous electrolyte has free flowability, and the active reaction components in the non-aqueous electrolyte continuously contact the lithium metal negative electrode interface and continuously generate side reactions, resulting in low coulombic efficiency, short cycle life and short storage life of the lithium metal battery cells.

[0069] Based on this, the embodiments of the present application provide a gel polymer electrolyte composition which can form a gel polymer electrolyte after polymerization and can improve the cycle life and storage life of the battery cells.

[0070] The gel polymer electrolyte composition provided by the embodiments of the present application comprises a non-aqueous electrolyte, a monomer represented by formula I and a polymer represented by formula II.

[0071]

[0072] N of R1, R2, R3, R4, R5 and R6 are active groups, and the N active groups are independently selected from any one of vinyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine group, amine group-substituted C1-C5 alkyl, mercapto group, mercapto group-substituted C1-C5 alkyl, isocyanate group, methylene isocyanate group, acrylate group and methacrylate group, and the remaining (6-N) are independently selected from any one of H, C1-C5 alkyl, C1-C5 halogenated alkyl and C1-C5 oxaalkyl, and N is 3, 4, 5 or 6.

[0073] R7 and R8 are independently selected from any one of vinyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine group, amine group-substituted C1-C5 alkyl, mercapto group, mercapto group-substituted C1-C5 alkyl, isocyanate group, methylene isocyanate group, acrylate group and methacrylate group, and R7 and R8 can undergo a polymerization reaction with the N active groups in R1, R2, R3, R4, R5 and R6.

[0074] M1, M2, M3, M4, M5 and M6 are independently selected from any one of H, halogen atom, C1-C5 halogenated alkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine group, amine group-substituted C1-C5 alkyl, C1-C5 alkyl and C1-C5 oxaalkyl at each occurrence, and at least one of M1, M2, M3, M4, M5 and M6 is selected from any one of halogen atom, C1-C5 halogenated alkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine group and amine group-substituted C1-C5 alkyl.

[0075] n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n x m is 10-10000.

[0076] The gel polymer electrolyte composition provided by the embodiments of the present application comprises monomers of Formula I and polymers of Formula II, the monomers of Formula I and the polymers of Formula II can undergo polymerization, and thus the gel polymer electrolyte can be formed after polymerization. The monomers of Formula I and the polymers of Formula II form a polymer skeleton of the gel polymer electrolyte after polymerization. The gel polymer electrolyte is flexible and can have good contact with the electrode interface, thereby reducing the interface impedance.

[0077] The monomers of Formula I and the polymers of Formula II have benzene rings, which have rigidity and large π-bond structures, and thus the strength of the gel polymer electrolyte can be improved. The polymers of Formula II also have ether oxygen chain segments, which have flexibility, and thus the polymer skeleton network formed has both rigidity and flexibility, so that the gel polymer electrolyte can maintain good contact with the electrode interface under the continuous expansion and contraction of the battery cell during cyclic charging and discharging, and the gel polymer electrolyte is not prone to breakage, thereby enabling the battery cell to have a long cycle life and storage life. The polymers of Formula II have ether oxygen chain segments, which have good affinity for non-aqueous electrolyte, and thus the non-aqueous electrolyte can be bound in the polymer skeleton network, so that it cannot flow freely. In this way, on the one hand, the side reaction of continuous consumption of active lithium of the unstable organic solvent and lithium salt anion in the non-aqueous electrolyte on the negative electrode interface can be reduced, and on the other hand, it is beneficial to the long-term stable infiltration of the non-aqueous electrolyte into the electrode assembly, reducing the occurrence of local dryness, thereby improving the cycle life of the battery cell.

[0078] At least one of M1, M2, M3, M4, M5, and M6 in the polymers of Formula II is selected from any one of a halogen atom, a C1-C5 halogenated alkyl group, a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, and an amine-substituted C1-C5 alkyl group, which can form a strong hydrogen bond interaction with the organic solvent and the lithium salt anion in the non-aqueous electrolyte, and through the hydrogen bond interaction, the organic solvent and the lithium salt anion can be anchored, so that they cannot migrate to the lithium metal negative electrode interface at will to cause the side reaction of consumption of active lithium.

[0079] n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n x m is 10-10000, and thus the polymer skeleton network formed has both rigidity and flexibility, so that the gel polymer electrolyte can maintain good contact with the electrode interface under the continuous expansion and contraction of the battery cell during cyclic charging and discharging, and the gel polymer electrolyte is not prone to breakage, thereby enabling the battery cell to have a long cycle life and storage life.

[0080] Therefore, the gel polymer electrolyte composition provided by the embodiments of the present application can be used in a battery monomer, can reduce the interface side reaction, and can improve the cycle life and storage life of the battery monomer.

[0081] n is an integer between 1 and 1000, for example, can be 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 900, 1000, or a range consisting of any of the above values.

[0082] Alternatively, in some embodiments, n can be an integer between 2 and 500, an integer between 2 and 400, an integer between 2 and 200, an integer between 2 and 100, or an integer between 2 and 50.

[0083] n is in the above range, which can make the polymer represented by formula II have flexibility and a suitable ratio of ether oxygen segment to benzene ring, so that the gel polymer electrolyte has good mechanical properties.

[0084] m is an integer between 1 and 1000, for example, can be 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 900, 1000, or a range consisting of any of the above values.

[0085] Alternatively, in some embodiments, m can be an integer between 5 and 800, an integer between 5 and 500, an integer between 5 and 400, an integer between 5 and 300, an integer between 20 and 200, an integer between 20 and 800, an integer between 20 and 500, an integer between 20 and 400, an integer between 20 and 300, or an integer between 20 and 200.

[0086] m is in the above range, which can make the formed gel polymer electrolyte have a more suitable skeleton space, so that the gel polymer electrolyte can completely accommodate the non-aqueous electrolyte even if the mass fraction of the polymer skeleton is low, and good ion transmission characteristics can be achieved.

[0087] n x m is 10-10000, for example, can be 10000, 8000, 6000, 5000, 4000, 3000, 2500, 2000, 1500, 1000, 500, 200, 100, 50, 10, or a range consisting of any of the above values.

[0088] Optionally, in some embodiments, n x m can be 50-5000, 50-4000, 50-3000, 50-2500, 50-2000, 100-4000, 100-3000, 100-2500, 100-2000.

[0089] n x m in the above range can make the battery monomer have longer cycle life and storage life.

[0090] In some embodiments, the weight average molecular weight of the polymer of Formula II can be 7500-650,000, for example, 7500, 8000, 10,000, 20,000, 40,000, 100,000, 800,000, 1,000,000, 1,200,000, 1,600,000, 1,800,000, 2,000,000, 2,200,000, 2,400,000, 2,800,000, 3,200,000, 3,600,000, 4,000,000, 4,500,000, 6,500,000, or a range consisting of any of the foregoing.

[0091] Optionally, the weight average molecular weight of the polymer of Formula II can be 7500-360,000, 7500-240,000, 7500-220,000, 7500-200,000, 7500-180,000, 7500-160,000.

[0092] The weight average molecular weight of the polymer of Formula II in the above range can make the battery monomer have longer cycle life and storage life.

[0093] In some embodiments, the polymerization reaction of R7 and R8 with N active groups in R1, R2, R3, R4, R5, R6 includes condensation polymerization reaction, addition polymerization reaction.

[0094] In some embodiments, the N active groups in R1, R2, R3, R4, R5, R6 can be the same.

[0095] In some embodiments, R7 and R8 can be the same.

[0096] In some embodiments, the N active groups in R1, R2, R3, R4, R5, R6 can be selected from any one of hydroxyl, hydroxyl-substituted C1-C5 alkyl, amine group, amine group-substituted C1-C5 alkyl, and R7 and R8 can be selected from any one of isocyanate group, methylene isocyanate group. Optionally, the N active groups in R1, R2, R3, R4, R5, R6 can be selected from any one of hydroxyl, amine group, and R7 and R8 can be selected from any one of isocyanate group, methylene isocyanate group.

[0097] In some embodiments, N active groups in R1, R2, R3, R4, R5, R6may be independently selected from any one of isocyanate group, methylene isocyanate group, R7and R8may be selected from any one of hydroxyl group, hydroxyl-substituted C1-C5 alkyl group, amine group, amine-substituted C1-C5 alkyl group. Alternatively, N active groups in R1, R2, R3, R4, R5, R6may be independently selected from any one of isocyanate group, methylene isocyanate group, R7and R8may be selected from any one of hydroxyl group, amine group.

[0098] The polymerization reaction of R7and R8with N active groups in R1, R2, R3, R4, R5, R6is condensation polymerization. The condensation polymerization does not require additional initiator and does not cause other side reactions. In addition, the condensation polymerization of hydroxyl group and isocyanate group generates polyurethane, and the condensation polymerization of amine group and isocyanate group generates polyurea. The polyurethane and polyurea have dynamic hydrogen bond structure, which is conducive to the formation of polymer network structure with flexibility and self-repairing characteristics. The polymer network structure has good positive and negative electrode stability and structural strength, which is conducive to the good mechanical stability and electrochemical stability of the gel polymer electrolyte in the long cycle process of the battery cell.

[0099] In some embodiments, N active groups in R1, R2, R3, R4, R5, R6may be selected from vinyl group, R7and R8may be selected from any one of vinyl group, acrylate group, methacrylate group, thiol group, thiol-substituted C1-C5 alkyl group.

[0100] In some embodiments, N active groups in R1, R2, R3, R4, R5, R6may be selected from any one of thiol group, thiol-substituted C1-C5 alkyl group, R7and R8may be selected from vinyl group.

[0101] In some embodiments, N active groups in R1, R2, R3, R4, R5, R6may be independently selected from any one of acrylate group, methacrylate group, R7and R8may be selected from any one of vinyl group, acrylate group, methacrylate group.

[0102] In some embodiments, N can be 3 or 4.

[0103] In some embodiments, N can be 3, R1, R3, R5may be active groups. Alternatively, N can be 3, R1, R3, R5may be active groups, R2, R4, R6may be selected from H.

[0104] In some embodiments, the monomer represented by formula I can be selected from any one of the following:

[0105]

[0106] In some embodiments, one or two of M1, M2, M3, M4, M5, M6may be selected from any one of a halogen atom, a C1-C5haloalkyl group, a hydroxyl group, a hydroxyl-substituted C1-C5alkyl group, an amine group, an amine-substituted C1-C5alkyl group. Alternatively, one or two of M1, M2, M3, M4, M5, M6may be selected from any one of a halogen atom, a hydroxyl group, an amine group.

[0107] In some embodiments, at least one of M1, M2, M3, M4, M5, M6may be selected from any one of a hydroxyl group, a hydroxyl-substituted C1-C5alkyl group. The hydroxyl group can form strong hydrogen bonding with oxygen, fluorine, nitrogen, etc. atoms in the organic solvent of the non-aqueous electrolyte and the anion of the lithium salt, and thus can better play an anchoring role on the organic solvent and the anion of the lithium salt.

[0108] Alternatively, one or two of M1, M2, M3, M4, M5, M6may be selected from any one of a hydroxyl group, a hydroxyl-substituted C1-C5alkyl group.

[0109] More alternatively, one or two of M1, M2, M3, M4, M5, M6may be selected from a hydroxyl group, and the rest can be selected from H.

[0110] One or two of M1, M2, M3, M4, M5, M6selected from a hydroxyl group can reduce the consumption of active lithium in the formation of a solid electrolyte interface (SEI) film.

[0111] In some embodiments, the polymer represented by Formula II can be selected from any one of the following:

[0112]

[0113] In some embodiments, the molar ratio of the monomer represented by Formula I to the polymer represented by Formula II can be 2:N. This can enable the end groups of the monomer represented by Formula I and the polymer represented by Formula II to match and react.

[0114] In some embodiments, the total mass fraction of the monomer represented by Formula I and the polymer represented by Formula II can be 0.5%-20%, for example, can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or a range consisting of any of the above values, based on the total mass of the gel polymer electrolyte composition.

[0115] Alternatively, the total mass fraction of the monomer represented by Formula I and the polymer represented by Formula II can be 1%-15%, 2%-10%, 3%-8%.

[0116] In some embodiments, the gel polymer electrolyte composition can further include an initiator.

[0117] Optionally, the mass of the initiator can be 0.1%-10% of the total mass of the monomer of Formula I and the polymer of Formula II. The appropriate amount of initiator is conducive to the sufficient polymerization of the monomer of Formula I and the polymer of Formula II.

[0118] Optionally, the initiator can include one or more of azo initiators, peroxide initiators, for example, can include one or more of azobisisobutyronitrile (AIBN), azobisisoheptane (AMVN), acetyl peroxide, hydrogen peroxide.

[0119] The non-aqueous electrolyte includes a lithium salt and an organic solvent. The non-aqueous electrolyte can be a high-concentration electrolyte or a locally high-concentration electrolyte, whereby the cycle life and storage life of the battery cell can be further improved.

[0120] In some embodiments, the lithium salt can include, but is not limited to, one or more of lithium bisfluorosulfonylimide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium bis(trifluoromethyl)sulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiOTF), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorodioxalate phosphate, lithium tetrafluorodioxalate phosphate.

[0121] Optionally, the lithium salt can include lithium bisfluorosulfonylimide (LiFSI). This lithium salt can decompose on the surface of the negative electrode to form an SEI film component rich in inorganic fluorine, thereby facilitating the battery cell to have a long cycle life; at the same time, this lithium salt also has good oxidation stability, which can support the cycle of the battery cell under high pressure.

[0122] In some embodiments, the lithium salt concentration of the non-aqueous electrolyte can be 0.5mol / L-4mol / L, for example, can be 0.5mol / L, 1mol / L, 1mol / L, 1.5mol / L, 2mol / L, 2.5mol / L, 3mol / L, 3.5mol / L, 4mol / L, or a range consisting of any of the above values. Optionally, the lithium salt concentration of the non-aqueous electrolyte can be 1.5mol / L-3.5mol / L, 2mol / L-3.5mol / L.

[0123] In some embodiments, the organic solvent can include an ether solvent. The ether solvent can include one or more of a chain ether solvent, a cyclic ether solvent.

[0124] The chain ether solvent can include, but is not limited to, one or more of diethyl ether, dipropyl ether, ethyl propyl ether, methyl butyl ether, dibutyl ether, ethyl butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol methyl ethyl ether, propylene glycol diethyl ether, butanediol dimethyl ether, butanediol methyl ethyl ether, butanediol diethyl ether. The cyclic ether solvent can include, but is not limited to, one or more of tetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxolane, tetrahydropyran, 1,3-dioxane, 1,4-dioxane.

[0125] Optionally, the organic solvent can include one or both of ethylene glycol dimethyl ether (DME) and propylene glycol dimethyl ether (DMP). Such organic solvents have good lithium salt solubility and positive and negative electrode stability, which is conducive to fast ion conduction and positive and negative electrode interface stability.

[0126] In some embodiments, the non-aqueous electrolyte can further include a diluent. The diluent can include, but is not limited to, one or more of benzene, fluorobenzene, p-difluorobenzene, m-difluorobenzene, o-difluorobenzene, trifluorotoluene, trifluoromethoxybenzene, decafluoropentane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,2-dimethoxy-1,1,2,2-tetrafluoroethane, 1,2-bis(difluoromethoxy)ethane, 1,2-bis(trifluoromethoxy)ethane, 1,2-diethoxy-1,1,2,2-tetrafluoroethane, 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane, bis(2,2,2-trifluoroethyl) ether, bis(2,2-difluoroethyl) ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, ethyl trifluoromethyl ether, difluoromethyl-2,2,3,3,3-pentafluoropropyl ether, heptafluoropropyl-1,2,2,2-tetrafluoroethyl ether, difluoromethyl 2,2,3,3-tetrafluoropropyl ether, perfluoroisopropyl methyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, ethyl-1,1,2,2-tetrafluoroethyl ether, ethyl-2,2,2-tetrafluoroethyl ether, bis(1,1,2,2-tetrafluoroethyl) ether.

[0127] Optionally, the diluent can include one or both of benzene and 1,2-bis(difluoromethoxy)ethane. Such diluents have low viscosity, low molecular weight, and high stability, which can improve the interface stability of the positive and negative electrodes, while reducing the viscosity and increasing the electrical conductivity of the non-aqueous electrolyte, thereby improving the ion transport properties of the gel polymer electrolyte formed by polymerization.

[0128] In some embodiments, the non-aqueous electrolyte can simultaneously include an organic solvent and a diluent, and the mass fraction of the organic solvent can be 10%-80% and the mass fraction of the diluent can be 20%-90%, based on the total mass of the organic solvent and the diluent being 100%.

[0129] Optionally, the mass fraction of the organic solvent can be less than the mass fraction of the diluent.

[0130] Optionally, the mass fraction of the organic solvent can be 20%-40% and the mass fraction of the diluent can be 60%-80%, based on the total mass of the organic solvent and the diluent being 100%.

[0131] The embodiments of the present application also provide a gel polymer electrolyte, which is obtained by polymerizing the gel polymer electrolyte composition described above.

[0132] The embodiments of the present application also provide a battery cell. The battery cell includes a gel polymer electrolyte, which is obtained by polymerizing the gel polymer electrolyte composition described above.

[0133] The battery cell provided by the embodiments of the present application includes the gel polymer electrolyte obtained by polymerizing the gel polymer electrolyte composition described above, and the polymer skeleton structure of the gel polymer electrolyte can bind the non-aqueous electrolyte, thereby reducing the interface side reaction, reducing the consumption of the non-aqueous electrolyte and active lithium, and also having a longer cycle life and storage life.

[0134] Optionally, the polymerization method is in-situ curing polymerization.

[0135] The type of the polymer skeleton structure of the gel polymer electrolyte can be obtained by NMR, FT-IR and the like. Illustratively, after the battery cell is disassembled, a residual space gel polymer electrolyte sample is taken, and is injected into an NMR sample tube or an FT-IR sample table for testing. The obtained result spectrum is compared and analyzed with a standard spectrum to determine the specific structure, and the type of the polymer skeleton structure is obtained through comprehensive analysis.

[0136] The mass fraction of the skeleton structure of the gel polymer electrolyte and the bound non-aqueous electrolyte can be obtained by freeze-drying. Illustratively, after the battery cell is disassembled, a residual space gel polymer electrolyte sample is taken, and the mass m1 of the sample is weighed. Then, the sample is placed in a freeze dryer for freeze-drying. After freeze-drying, the mass m2 of the residual sample is weighed, and m1-m2 is the mass of the organic solvent in the non-aqueous electrolyte. The freeze-dried sample is then washed and dried with ethylene glycol dimethyl ether. The mass m3 of the dried sample is weighed again, which is the mass of the polymer skeleton, and m2-m3 is the mass of the lithium salt. Thus, the mass fractions of different components in the gel polymer electrolyte, such as the polymer skeleton, the non-aqueous electrolyte, the organic solvent and the lithium salt, can be obtained.

[0137] The battery cell further includes a positive electrode tab, a negative electrode tab, and a separator.

[0138] The battery cell provided by the embodiments of the present application can include a lithium metal battery cell, a negative electrode-free lithium metal battery cell.

[0139] Taking the lithium metal battery cell as an example, the negative electrode tab can include a negative electrode current collector and a lithium metal layer disposed on at least one surface of the negative electrode current collector. The lithium metal layer includes elemental lithium or an alloy of lithium and other metals or quasi-metals. Optionally, the other metal elements include one or more of Sn, Zn, Al, Mg, Ag, Au, Ga, In, and Pt. Optionally, the other quasi-metal elements include one or more of B, C, and Si.

[0140] The negative electrode-free lithium metal battery cell generally refers to a battery cell that is not actively provided with a negative electrode active material layer on the negative electrode side during the manufacturing process of the battery cell, for example, a carbon-based active material layer is not disposed on the negative electrode by coating or deposition or other processes during the manufacturing process of the battery cell to form a negative electrode active material layer. During the first charging, ions obtain electrons on the negative electrode side and deposit on the surface of the negative electrode current collector to form a metal phase. During discharging, the metal can be converted into metal ions to return to the positive electrode, realizing the cycle of charging and discharging. Compared with other battery cells, the negative electrode-free lithium metal battery cell has no negative electrode active material layer, thereby achieving a higher energy density. In some embodiments, in order to improve the performance of the battery cell, some substances that can be used as negative electrode active materials, such as carbon materials, can also be disposed on the negative electrode side of the negative electrode-free lithium metal battery cell. Although these substances have a certain capacity, due to their small amount and not being used as the main negative electrode active material in the battery cell, the battery cell thus constituted can still be regarded as a negative electrode-free lithium metal battery cell. The CB value of the negative electrode-free lithium metal battery cell is usually very small, for example, in some embodiments, the CB value of the negative electrode-free lithium metal battery cell can be less than or equal to 0.1. The CB value is the capacity per unit area of the negative electrode in the battery cell divided by the capacity per unit area of the positive electrode. Since the negative electrode-free lithium metal battery cell does not contain or contains only a small amount of negative electrode active material, the capacity per unit area of the negative electrode is small, and thus the CB value is very small, for example, usually less than or equal to 0.1.

[0141] Taking the negative electrode-free lithium metal battery cell as an example, the negative electrode tab can include a negative electrode current collector and does not include a lithium metal layer. During the cycle of charging and discharging of the negative electrode-free lithium metal battery cell, lithium of the positive electrode will be deposited and peeled off in the form of lithium metal on the negative electrode side.

[0142] In some embodiments, the negative current collector can employ a metal foil or a composite current collector. As an example of the metal foil, a copper foil, a copper alloy foil, a nickel foil, a nickel alloy foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0143] In some embodiments, the positive electrode tab includes a positive current collector and a positive film layer disposed on at least one surface of the positive current collector, the positive film layer including a positive active material. For example, the positive current collector has two surfaces opposite in the thickness direction of the positive current collector, and the positive film layer is disposed on either one or both of the two opposite surfaces of the positive current collector.

[0144] The positive active material includes a material capable of deintercalating and intercalating lithium, and optionally, the positive active material can include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and modified compounds of each of the foregoing. Examples of the lithium transition metal oxides can include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and modified compounds of each of the foregoing. Examples of the lithium-containing phosphates can include, but are not limited to, one or more of lithium iron phosphate, a composite of lithium iron phosphate and carbon, lithium manganese phosphate, a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon, and modified compounds of each of the foregoing.

[0145] The modified compounds of each of the foregoing positive active materials can be a doping modification and / or a surface coating modification of the positive active material.

[0146] In some embodiments, to further improve the energy density of the battery cell, the positive active material can include one or more of lithium transition metal oxides of the general formula Li a Ni b Co c M d O e A f 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A includes one or more of N, F, S, and Cl.

[0147] In some embodiments, the cathode active material can include, by way of example, but not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(also written as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(also written as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2(also written as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2(also written as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(also written as NCM811), LiNi 0.96 Co 0.02 Mn 0.02 O2(also written as Ni96), LiNi 0.80 Co 0.15 Al 0.05 O2, LiFePO4, LiMnPO4, and respective modified compounds thereof.

[0148] In some embodiments, the cathode film layer can also optionally include a cathode conductive agent. By way of example, the cathode conductive agent can include, but is not limited to, one or more of super P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0149] In some embodiments, the cathode film layer can also optionally include a cathode binder. By way of example, the cathode binder can include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic ester-based resin.

[0150] In some embodiments, the positive electrode current collector can employ a metal foil or a composite current collector. As an example of a metal foil, an aluminum foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0151] The positive electrode film layer can be formed by coating a positive electrode slurry on a positive electrode current collector, drying, and cold-pressing. The positive electrode slurry is generally formed by dispersing and uniformly stirring a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and any other components in a solvent. The solvent can be N-methyl pyrrolidone (NMP), but is not limited thereto.

[0152] The separator film can be disposed between the positive electrode tab and the negative electrode tab, and mainly functions to prevent internal short circuit. The type of the separator film is not particularly limited in the present application, and any publicly known porous structure film having good chemical stability and mechanical stability can be used. In some embodiments, the material of the separator film can include, but is not limited to, one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and polyimide. The separator film can be a single layer film or a multi-layer composite film. When the separator film is a multi-layer composite film, the materials of the layers can be the same or different.

[0153] The present application also provides a method for preparing a battery cell.

[0154] The method for preparing a battery cell includes the following steps: providing a battery cell to be injected with electrolyte, mixing the above gel polymer electrolyte composition to obtain a precursor solution, injecting the obtained precursor solution into the battery cell to be injected with electrolyte, and then treating under heating conditions to allow the precursor solution to in-situ solidify and polymerize into a gel polymer electrolyte inside the battery cell, thereby obtaining the battery cell.

[0155] In some embodiments, the heating temperature can be 60-80°C.

[0156] In some embodiments, the heating time can be 6-24 hours.

[0157] In some embodiments, the heating treatment can be performed during the standing and infiltration of the precursor solution, so as to allow the precursor solution to in-situ solidify and polymerize into a gel polymer electrolyte inside the battery cell.

[0158] Optionally, the precursor solution standing infiltration process can first be standing infiltration at 20-45°C for 2-12h to make the precursor solution infiltrate the battery cell to be injected with liquid; and then standing infiltration at 60-80°C for 6-24h to make the precursor solution in-situ solidify and polymerize to form a gel polymer electrolyte inside the battery cell.

[0159] The preparation method of the battery cell to be injected with liquid is known. In some embodiments, the positive electrode sheet, the separator, and the negative electrode sheet can be formed into an electrode assembly through a winding process and / or a stacking process, and the electrode assembly can be placed in an outer package. After drying, the battery cell to be injected with liquid is obtained.

[0160] Electricity-using device

[0161] The embodiments of the present application also provide a power utilization device, which comprises the battery provided by the embodiments of the present application. The battery can be used as a power source of the power utilization device, or can be used as an energy storage unit of the power utilization device. The power utilization device can be, but is not limited to, a mobile device (such as a mobile phone, a tablet computer, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc.

[0162] The power utilization device can select the type of the battery (such as a battery cell, a battery module, or a battery pack) according to the use requirement of the power utilization device.

[0163] Figure 6 FIG. 1 is a schematic diagram of a power utilization device as an example. The power utilization device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirement of high power and high energy density of the power utilization device, a battery pack or a battery module can be used.

[0164] The power utilization device as another example can be a mobile phone, a tablet computer, a notebook computer, etc. The power utilization device usually requires thinning, and a battery cell can be used as a power source.

[0165] Example

[0166] The embodiments described below more specifically describe the disclosure of the present application, which are merely illustrative and various modifications and changes within the scope of the disclosure of the present application are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and the instruments used in the embodiments are commercially available.

[0167] In the following examples and comparative examples, the monomers of Formula I are numbered as follows for simplicity.

[0168]

[0169] In the following examples and comparative examples, the polymers of Formula II are numbered as follows for simplicity.

[0170]

[0171] The present example exemplarily provides a method for preparing the polymer of Formula II numbered 18. Other polymers of Formula II of the present example can be prepared according to the exemplified method. According to the exemplified method for preparing the polymer of Formula II, one skilled in the art can easily obtain the specific method for implementing each synthetic step from the relevant scientific literature or standard textbooks in the art. Unless specifically indicated, commercially available or known in the literature compounds are used herein as starting materials for synthesis. One skilled in the art of organic synthesis will recognize that the nature and order of the synthetic steps can be varied for the purpose of optimizing the generation of the compounds described herein.

[0172] The process described in the present example can be monitored according to any suitable method known in the art. For example, product generation can be monitored by spectroscopic means such as nuclear magnetic resonance spectroscopy (NMR, e.g.1H NMR,13C NMR), infrared spectroscopy (IR), mass spectrometry (MS), X-ray photoelectron spectroscopy (XPS). 1 H, 13 C or 19 F), infrared spectroscopy (IR), mass spectrometry (MS), X-ray photoelectron spectroscopy (XPS).

[0173] Exemplarily, the synthesis method of the polymer of Formula II numbered 18 is as follows.

[0174]

[0175] After 2-(2,3-dihydrobenzofuran-6-yl)ethanol 1-ol (16.42 g, 0.1 mol) was dissolved in 60 mL of acetonitrile, it was stirred and cooled to 0°C, 2 mol / L hydrochloric acid solution was added dropwise, the pH was adjusted to 4-5, and after 15 min of incubation, the temperature was raised to 45°C and stirred for 3 h. After the reaction was completed, it was cooled to 0°C in an ice water bath, 1 mol / L sodium hydroxide solution was added to adjust the pH to 8-9, and stirred for 1 h. Then, methyl iodide (CH3I, 17.03 g, 0.12 mol) was added dropwise, the temperature was raised to room temperature (about 25°C) and stirred for 3 h after the dropwise addition was completed. After the reaction was completed, the organic solvent acetonitrile was removed by reduced pressure concentration, extracted with dichloromethane (50 mL x 3), washed with saturated brine, and then the organic phase was dried with anhydrous sodium sulfate, filtered, and the organic phase was concentrated by reduced pressure to remove the organic solvent dichloromethane (DCM) to obtain a crude product. The crude product was purified by V 乙酸乙酯 :V石油醚 = 1 : 10 recrystallization to obtain 12.02 g of white solid 1, ready for use.

[0176] 1 H NMR (DMSO-d6, 400 MHz), δ (ppm): 6.96 (m, 1H), 6.58 (m, 2H), 3.86 (m, 4H), 3.73 (s, 3H), 2.74 (m, 4H), 2.02 (m, 2H). 13 C NMR (DMSO-d6, 100 MHz), δ (ppm): 161.3, 138.4, 128.8, 123.0, 120.1, 113.4, 65.4, 65.1, 56.3, 39.0, 28.8. HRMS (ESI + )m / z [M] + calcd. for C 11 H 16 O3: 196.1099, found: 196.1093.

[0177] Compound 1 (5 g, 25.48 mmol) was dissolved in 50 mL of N, N-dimethylformamide (DMF), stirred and cooled to -20 to -10 °C, then 2 mol / L sodium hydroxide solution was added dropwise, pH was adjusted to 10-12, after dropwise addition was completed, ethylene glycol (0.79 g, 12.74 mmol) was added dropwise, after dropwise addition was completed, methanol amine (2.40 g, 50.96 mmol) was added, after stirring for 30 min, the temperature was raised to 45 °C and stirred for 3 h. After the reaction was completed, the reaction liquid was injected into a dialysis bag (5 kDa) and dialyzed until the water outside the dialysis bag was neutral, and finally freeze-dried to obtain 6.12 g (mass yield: 74.73%) of polymer 2. Elements analysis: calcd: C, 62.83; H, 8.63; N, 13.32; O, 15.22. Found: C, 62.46; H, 8.58; N, 13.13; O, 15.83. M n : 6000, PDI: 1.8.

[0178]

[0179] To 4 g of polymer 2 dissolved in 30 mL of N,N-dimethylformamide (DMF), stirring and cooling to 0 °C, BBr3 / DCM solution was added dropwise until the 3.73 methyl peak was not shifted in the nuclear magnetic resonance spectrum, after the dropwise addition was completed, ice was added to quench the reaction, the reaction solution was injected into a dialysis bag (5 kDa) and dialyzed until the water outside the dialysis bag was neutral, and finally 2.2 g of polymer was obtained by freeze-drying, which was the polymer represented by formula II numbered 18. Elements analysis: calcd: C, 61.20; H, 8.22; N, 14.27; O, 16.31. Found: C, 60.69; H, 8.57; N, 13.89; O, 16.85. M n : 6000, PDI: 2.0.

[0180] Example 1

[0181] (1) Preparation of a lithium metal battery monomer to be injected

[0182] The positive active material LiNi 0.8 Co 0.1 Mn 0.1 O2, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 98:1:1, added to the solvent N-methyl pyrrolidone (NMP), and stirred until the system was uniform, obtaining a positive electrode slurry with a solid content of about 70%; the positive electrode slurry was uniformly coated on both surfaces of the positive electrode current collector aluminum foil at a loading of about 12.5 mg / cm 2 After air drying, it was transferred to an oven for further drying, and then cut into a 40 mm x 50 mm rectangle as a positive electrode sheet for standby.

[0183] The polyethylene porous film was cut into a 45 mm x 55 mm rectangle as a separator film for standby.

[0184] A 50 μm lithium foil was coated on a 12 μm copper foil by rolling, and then cut into a 41 mm x 51 mm rectangle as a negative electrode sheet for standby.

[0185] A piece of the cut positive electrode sheet was matched with two pieces of the cut negative electrode sheet, the above-mentioned separator film was used in the middle to isolate, and was wrapped in an aluminum plastic film bag to form a lithium metal battery monomer to be injected.

[0186] (2) Preparation of a non-aqueous electrolyte

[0187] Ethylene glycol dimethyl ether (DME) and 1,2-bis(difluoromethoxy)ethane were mixed in a mass ratio of 3:7 to form a solvent mother liquor; 2.805 g of lithium bisfluorosulfonylimide (LiFSI) was added to 5 ml of the solvent mother liquor, and stirred thoroughly to form a colorless transparent non-aqueous electrolyte.

[0188] (3) Preparation of the finished lithium metal battery cell

[0189] After the monomer of formula I numbered 1 and the polymer of formula II numbered 1 are pre-mixed in a molar ratio of 2:3, an appropriate amount of the non-aqueous electrolyte prepared above is injected to form a precursor solution, and the total mass fraction of the monomer of formula I and the polymer of formula II in the precursor solution is 5%; 0.3 g of the precursor solution is injected into the lithium metal battery cell prepared above, and then the aluminum plastic film bag is vacuum heat sealed and packaged, and after standing at 25°C for 6 hours, it is transferred to 60°C for 12 hours, so that the in-situ polymerization and curing reaction of the monomer of formula I and the polymer of formula II is completed, forming a gel polymer electrolyte, i.e. a finished lithium metal battery cell. The rated capacity of the lithium metal battery cell is 70 mAh.

[0190] Examples 2 to 26

[0191] The preparation method of the finished lithium metal battery cell is the same as that of Example 1, except that one or more of the type of monomer of formula I, the type of polymer of formula II, and the molar ratio of the monomer of formula I to the polymer of formula II are different, and the specific parameters are shown in Table 1. Optionally, according to the different reaction types between the monomer of formula I and the polymer of formula II, an initiator can also be added to the precursor solution, such as 0.05% AIBN based on the total mass of the monomer of formula I and the polymer of formula II.

[0192] Comparative Example 1

[0193] (1) Preparation of the lithium metal battery cell to be injected

[0194] The same as Example 1.

[0195] (2) Preparation of the non-aqueous electrolyte

[0196] The same as Example 1.

[0197] (3) Preparation of the finished lithium metal battery cell

[0198] 0.3 g of the non-aqueous electrolyte is injected into the lithium metal battery cell prepared above, and then the aluminum plastic film bag is vacuum heat sealed and packaged, and after standing at 25°C for 6 hours, it is transferred to 60°C for 12 hours, to obtain a finished lithium metal battery cell. The rated capacity of the lithium metal battery cell is 70 mAh.

[0199] Comparative Examples 2 to 3

[0200] The preparation method of the finished lithium metal battery cell is the same as that of Example 1, except that the type of polymer of formula II is different, and the specific parameters are shown in Table 1.

[0201] Cycling performance test

[0202] Take the above prepared lithium metal battery monomer, set the ambient temperature to 25℃, use 0.2C (i.e. 14mA) constant current charging to reach the cut-off voltage 4.3V, then continue to use 4.3V constant voltage charging until the current decays to 0.1C (i.e. 7mA); then discharge at 1C (i.e. 70mA) constant current to 2.8V to get the first circle discharge capacity. Repeat the above charge and discharge cycle, record the discharge capacity after each cycle. When the discharge capacity decays to 80% of the first circle discharge capacity, the lithium metal battery monomer is considered to have reached the end of life, and the number of cycles the lithium metal battery monomer has undergone is recorded as the cycle life of the lithium metal battery monomer.

[0203] High temperature storage performance test

[0204] Take the above prepared lithium metal battery monomer, set the ambient temperature to 25℃, use 0.2C (i.e. 14mA) constant current charging to reach the cut-off voltage 4.3V, then continue to use 4.3V constant voltage charging until the current decays to 0.1C (i.e. 7mA), then discharge at 1C (i.e. 70mA) constant current to 2.8V to get the initial capacity; then use 0.2C (i.e. 14mA) constant current charging to reach the cut-off voltage 4.3V, then continue to use 4.3V constant voltage charging until the current decays to 0.1C (i.e. 7mA), at this time the lithium metal battery monomer is in a full charge state, the full charge state of the lithium metal battery monomer is transferred into a constant temperature oven at 60℃ for 1 month, and after the temperature of the lithium metal battery monomer drops to 25℃, it is discharged at 1C (i.e. 70mA) constant current to 2.8V, then use 0.2C (i.e. 14mA) constant current charging to reach the cut-off voltage 4.3V, then continue to use 4.3V constant voltage charging until the current decays to 0.1C (i.e. 7mA), then discharge at 1C (i.e. 70mA) constant current to 2.8V, this circle capacity is recorded as the recovery capacity; then use 0.2C (i.e. 14mA) constant current charging to reach the cut-off voltage 4.3V, then continue to use 4.3V constant voltage charging until the current decays to 0.1C (i.e. 7mA), at this time the lithium metal battery monomer is in a full charge state, the full charge state of the lithium metal battery monomer is transferred into a constant temperature oven at 60℃ for 1 month; this cycle is repeated until the recovery capacity obtained by the above method decays to 80% of the initial capacity, and the total storage time (in months) at this time is taken as the high temperature storage life of the lithium metal battery monomer. The larger the value, the better the high temperature stability of the lithium metal battery monomer.

[0205] Table 1

[0206]

[0207]

[0208] From the test results of Examples 1 to 26 and Comparative Example 1, it can be seen that the cycle life and storage life of the lithium metal battery cell using the gel polymer electrolyte are superior to those of the lithium metal battery cell using the non-aqueous electrolyte (i.e., the lithium metal battery cell of Comparative Example 1). This is because the gel polymer electrolyte plays a wrapping and anchoring role on the organic solvent having high interfacial reactivity and the lithium salt anion of the non-aqueous electrolyte, thereby making the non-aqueous electrolyte unable to flow freely, making the non-aqueous electrolyte unable to be reduced at the lithium metal negative electrode interface, and thus reducing the consumption of active lithium, thereby improving the cycle life and storage life of the metal battery cell.

[0209] From the test results of Examples 1 to 14, it can be seen that the improvement effects on the cycle life and storage life of the lithium metal battery cell are different for the polymers of Formula II with different n and / or m, different ether oxygen atom contents, and different benzene ring structure contents. The molecular weight of the polymer of Formula II of Comparative Example 2 is too large, at which time the formed gel polymer electrolyte has almost no flexibility and is easy to crystallize, the gel polymer electrolyte has poor adhesion to the electrode interface, and the ion transport characteristics are poor.

[0210] From the test results of Examples 1, Examples 15 to 25, and Comparative Example 3, it can be seen that by forming a hydrogen bond interaction between at least one of M1, M2, M3, M4, M5, and M6 and the organic solvent and the lithium salt anion in the non-aqueous electrolyte, the lithium metal battery cell can have good cycle life and storage life.

[0211] From the test results of Examples 1, Examples 15 to 25, it can be further seen that by further optimizing the structures of the monomer of Formula I and the polymer of Formula II, the cycle life and storage life of the lithium metal battery cell can be further improved.

[0212] From the test results of Examples 1 and Example 26, it can be seen that by optimizing the molar ratio of the structures of the monomer of Formula I and the polymer of Formula II, the monomer of Formula I and the end group of the polymer of Formula II can be matched for reaction, thereby further improving the cycle life and storage life of the lithium metal battery cell.

[0213] Examples 2-1 to 2-4

[0214] The preparation method of the lithium metal battery cell is the same as that of Example 1, except that the total mass content of the monomer of Formula I and the polymer of Formula II in the precursor solution is different.

[0215] Table 2

[0216]

[0217] The test results show that the total mass fraction of the monomer represented by Formula I and the polymer represented by Formula II in the precursor solution is different, and the cycle life and storage performance of the lithium metal battery cell are different.

[0218] Examples 3-1 to 3-18 and Comparative Example 4

[0219] The preparation method of the lithium metal battery cell is the same as that of Example 1, except that the non-aqueous electrolyte composition in the precursor solution is different.

[0220] In the following examples and comparative examples, for the sake of brevity, the non-aqueous electrolyte numbers are as follows.

[0221]

[0222]

[0223] Table 3

[0224]

[0225]

[0226] The test results show that the composition of the non-aqueous electrolyte also affects the cycle life of the lithium metal battery cell.

[0227] Comparative Example 4 uses an ester solvent, which has high reactivity to the lithium metal negative electrode of the lithium metal battery cell, and can cause severe active lithium corrosion during cycling, thus resulting in poor cycle life and storage life of the lithium metal battery cell.

[0228] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect within the scope of the technical solutions of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art, other modes constructed by combining part of the constituent elements of the embodiments are also included in the scope of the present application.

Claims

1. A gel polymer electrolyte composition, characterized by, comprise: a non-aqueous electrolyte solution, a monomer represented by Formula I, and a polymer represented by Formula II, N of R1, R2, R3, R4, R5, R6 are active groups, and the N active groups are each independently selected from any one of a vinyl group, a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, an amine-substituted C1-C5 alkyl group, a mercapto group, a mercapto-substituted C1-C5 alkyl group, an isocyanate group, a methylene isocyanate group, an acrylate group, and a methacrylate group, and the remaining (6-N) are each independently selected from any one of H, a C1-C5 alkyl group, a C1-C5 haloalkyl group, and a C1-C5 oxaalkyl group, and N is 3, 4, 5, or 6; R7 and R8 are each independently selected from any one of a vinyl group, a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, an amine-substituted C1-C5 alkyl group, a mercapto group, a mercapto-substituted C1-C5 alkyl group, an isocyanate group, a methylene isocyanate group, an acrylate group, and a methacrylate group, and R7 and R8 can be polymerized with the N active groups of R1, R2, R3, R4, R5, and R6; M1, M2, M3, M4, M5, M6 are each independently selected from any one of H, a halogen atom, a C1-C5 haloalkyl group, a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, an amine-substituted C1-C5 alkyl group, a C1-C5 alkyl group, and a C1-C5 oxaalkyl group, and at least one of M1, M2, M3, M4, M5, and M6 is selected from any one of a halogen atom, a C1-C5 haloalkyl group, a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, and an amine group; n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n x m is 10-10000.

2. The gel polymer electrolyte composition according to claim 1, wherein n is an integer between 2 and 400; and / or m is an integer between 5 and 800; and / or n x m is 100-4000.

3. The gel polymer electrolyte composition according to any one of claims 1-2, characterized in that, The weight average molecular weight of the polymer represented by Formula II is 7500-360,000.

4. The gel polymer electrolyte composition according to any one of claims 1 to 3, characterized in that, The polymerization of R7 and R8 with the N active groups of R1, R2, R3, R4, R5, and R6 includes condensation polymerization and addition polymerization.

5. The gel polymer electrolyte composition according to any one of claims 1-4, wherein the N active groups of R1, R2, R3, R4, R5, and R6 are the same; and / or R7 and R8 are the same.

6. The gel polymer electrolyte composition according to any one of claims 1 to 5, wherein The monomer represented by Formula I and the polymer represented by Formula II satisfy any one of the following conditions (1) to (5): (1) N of R1, R2, R3, R4, R5, and R6 are active groups selected from any one of a hydroxyl group, a hydroxyl-substituted C1-C5 alkyl group, an amine group, and an amine-substituted C1-C5 alkyl group, and R7 and R8 are selected from any one of an isocyanate group and a methylene isocyanate group. (2) N of R1, R2, R3, R4, R5, R6 is independently selected from any one of isocyanate group, methylene isocyanate group, R7 and R8 are selected from any one of hydroxyl group, hydroxyl-substituted C1-C5 alkyl group, amine group, amine-substituted C1-C5 alkyl group; (3) N of R1, R2, R3, R4, R5, R6 is selected from vinyl group, R7 and R8 are selected from any one of vinyl group, acrylate group, methacrylate group, mercapto group, mercapto-substituted C1-C5 alkyl group; (4) N of R1, R2, R3, R4, R5, R6 is selected from any one of mercapto group, mercapto-substituted C1-C5 alkyl group, R7 and R8 are selected from vinyl group; (5) N of R1, R2, R3, R4, R5, R6 is independently selected from any one of acrylate group, methacrylate group, R7 and R8 are selected from any one of vinyl group, acrylate group, methacrylate group.

7. The gel polymer electrolyte composition according to any one of claims 1 to 6, characterized in that, N is 3, R1, R3, R5 are active groups.

8. The gel polymer electrolyte composition according to any one of claims 1 to 7, wherein The monomer represented by formula I is selected from any one of the following:

9. The gel polymer electrolyte composition according to any one of claims 1 to 8, characterized in that, One or two of M1, M2, M3, M4, M5, M6 is selected from any one of halogen atom, C1-C5 halogenated alkyl group, hydroxyl group, hydroxyl-substituted C1-C5 alkyl group, amine group, amine-substituted C1-C5 alkyl group.

10. The gel polymer electrolyte composition according to any one of claims 1 to 9, characterized in that, The polymer represented by formula II is selected from any one of the following:

11. The gel polymer electrolyte composition according to any one of claims 1 to 10, wherein The molar ratio of the monomer represented by formula I to the polymer represented by formula II is 2:N.

12. The gel polymer electrolyte composition according to any one of claims 1 to 11, wherein, The total mass fraction of the monomer represented by formula I and the polymer represented by formula II is 0.5%-20% based on the total mass of the gel polymer electrolyte composition.

13. The gel polymer electrolyte composition according to any one of claims 1 to 12, wherein The gel polymer electrolyte composition further comprises an initiator.

14. A gel polymer electrolyte, characterized by, The gel polymer electrolyte composition of any one of claims 1-13 is polymerized.

15. A battery cell, characterized by The gel polymer electrolyte obtained by polymerizing the gel polymer electrolyte composition of any one of claims 1-13.

16. The battery cell of claim 15, wherein, The method of polymerizing the gel polymer electrolyte composition of any one of claims 1-13 is in-situ solidification polymerization.

17. A method for preparing a battery monomer, comprising the following steps: providing a battery monomer to be injected, mixing the gel polymer electrolyte composition of any one of claims 1-13 to obtain a precursor liquid, injecting the obtained precursor liquid into the battery monomer to be injected, and then treating under heating conditions to make the precursor liquid in-situ solidification polymerization inside the battery monomer to form a gel polymer electrolyte, thereby obtaining a battery monomer.

18. A battery, characterized by The battery monomer of any one of claims 15-16 or prepared by the method of claim 17.

19. An electrical device, comprising: The battery of claim 18.

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