Gel polymer electrolyte composition, gel polymer electrolyte, battery cell and manufacturing method therefor, and electrical apparatus

Abstract

Disclosed in the present application are a gel polymer electrolyte composition, a gel polymer electrolyte, a battery cell and a manufacturing method therefor, and an electrical apparatus. The gel polymer electrolyte composition comprises: a non-aqueous electrolyte, a monomer represented by formula (I), and a polymer represented by formula (II). The gel polymer electrolyte composition is used in battery cells, thereby improving the cycle life and storage life of battery cells.

Description

Gel polymer electrolyte composition, gel polymer electrolyte, battery cell and its preparation method, and electrical device.

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410781703.6, filed on June 17, 2024, entitled “Gel polymer electrolyte composition, gel polymer electrolyte, battery cell and preparation method thereof, electrical device thereof”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to a gel polymer electrolyte composition, a gel polymer electrolyte, a battery cell and its preparation method, and an electrical device. Background Technology

[0004] Lithium metal battery cells, which use lithium metal as the negative electrode, have significantly higher gravimetric and volumetric energy densities than lithium-ion battery cells, making them crucial for applications such as long-range electric vehicles, drones, and electric aircraft. However, compared to lithium-ion battery cells, lithium metal battery cells have poorer cycle life and storage life.

[0005] Summary of the Invention

[0006] This application provides a gel polymer electrolyte composition, a gel polymer electrolyte, a battery cell, a method for preparing the same, and an electrical device. The gel polymer electrolyte composition, when used in a battery cell, can improve the cycle life and storage life of the battery cell.

[0007] In a first aspect, this application provides a gel polymer electrolyte composition comprising: a non-aqueous electrolyte, a monomer of Formula I, and a polymer of Formula II.

[0008] Of R1, R2, R3, R4, R5, and R6, N are active groups, and each of these N active groups is independently selected from vinyl, hydroxy, hydroxy-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, mercapto, mercapto-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, and methacrylate. The remaining (6-N) groups are independently selected from H, C1-C5 alkyl, C1-C5 haloalkyl, and C1-C5 oxaalkyl, where N is 3, 4, 5, or 6. R7 and R8 are independently selected from vinyl, hydroxy, hydroxy-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, mercapto, mercapto-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, and methacrylate. R7 and R8 are any of the acrylate groups, and R7 and R8 can undergo polymerization reactions with N active groups from R1, R2, R3, R4, R5, and R6; each time M1, M2, M3, M4, M5, and M6 appear, they are independently selected from H, halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, C1-C5 alkyl, and C1-C5 oxaalkyl, and at least one of M1, M2, M3, M4, M5, and M6 is selected from halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, and amino-substituted C1-C5 alkyl; n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n×m is 10-10000.

[0009] The gel polymer electrolyte composition provided in this application includes a monomer shown in Formula I and a polymer shown in Formula II. The monomer shown in Formula I and the polymer shown in Formula II can undergo a polymerization reaction, thereby forming a gel polymer electrolyte after polymerization. The monomer shown in Formula I and the polymer shown in Formula II form the polymer backbone of the gel polymer electrolyte after polymerization. The gel polymer electrolyte is flexible and can have good contact with the electrode interface, thereby reducing interfacial impedance.

[0010] The monomer shown in Formula I and the polymer shown in Formula II possess benzene rings, which are rigid and have a large π-bond structure, thus improving the strength of the gel polymer electrolyte. The polymer shown in Formula II also contains ether-oxygen segments, which are flexible. This allows the formed polymer backbone network to possess both rigidity and flexibility, ensuring good contact between the gel polymer electrolyte and the electrode interface during the continuous expansion and contraction of the battery cell during charge-discharge cycles. Simultaneously, it prevents the gel polymer electrolyte from breaking down, thereby contributing to a long cycle life and storage life of the battery cell. The ether-oxygen segments in the polymer shown in Formula II have good affinity for non-aqueous electrolytes, binding the non-aqueous electrolyte within the polymer backbone network and preventing its free flow. This reduces the side reactions that continuously consume active lithium at the negative electrode interface caused by unstable organic solvents and lithium salt anions in the non-aqueous electrolyte. Furthermore, it facilitates the long-term stable wetting of the electrode assembly by the non-aqueous electrolyte, reducing localized drying problems and thus improving the cycle life of the battery cell.

[0011] In the polymer shown in Formula II, at least one of M1, M2, M3, M4, M5, and M6 is selected from any one of halogen atoms, C1-C5 haloalkyl groups, hydroxyl groups, hydroxyl-substituted C1-C5 alkyl groups, amino groups, and amino-substituted C1-C5 alkyl groups. These groups can form strong hydrogen bond interactions with organic solvents and lithium salt anions in non-aqueous electrolytes. Through hydrogen bond interactions, organic solvents and lithium salt anions can be anchored, preventing them from migrating freely with lithium ions to the lithium metal anode interface and causing side reactions that consume active lithium.

[0012] n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n×m is 10-10000. This allows the formed polymer skeleton network to have 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 charge and discharge cycles. At the same time, it can make the gel polymer electrolyte less prone to breakage, thereby enabling the battery cell to have a long cycle life and storage life.

[0013] Therefore, the gel polymer electrolyte composition provided in this application embodiment can reduce interfacial side reactions and improve the cycle life and storage life of the battery cell when used in a battery cell.

[0014] In some embodiments, n is an integer between 2 and 400. This allows the polymer shown in Formula II to possess both flexibility and a suitable ratio of ether oxygen segments to benzene rings, thereby enabling the gel polymer electrolyte to have good mechanical properties.

[0015] In some embodiments, m is an integer between 5 and 800. This allows the formed gel polymer electrolyte to have a suitable skeletal space, enabling the gel polymer electrolyte to fully accommodate non-aqueous electrolytes even with a low polymer skeletal mass fraction, thus achieving good ion transport characteristics.

[0016] In some embodiments, n×m is 100-4000. This can result in longer cycle life and storage life for individual battery cells.

[0017] In some embodiments, the polymer shown in Formula II has a weight-average molecular weight of 75 million to 360,000. This allows the battery cell to have a longer cycle life and storage life.

[0018] In some embodiments, the polymerization reactions of R7 and R8 with N active groups among R1, R2, R3, R4, R5, and R6 include condensation polymerization and addition polymerization.

[0019] In some embodiments, the N active groups in R1, R2, R3, R4, R5, and R6 are identical.

[0020] In some embodiments, R7 and R8 are the same.

[0021] In some embodiments, N active groups among R1, R2, R3, R4, R5, and R6 are selected from any one of hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, and amino-substituted C1-C5 alkyl, and R7 and R8 are selected from any one of isocyanate and methylene isocyanate.

[0022] In some embodiments, the N active groups in R1, R2, R3, R4, R5, and R6 are each independently selected from isocyanate groups and methylene isocyanate groups, and R7 and R8 are selected from hydroxyl groups, hydroxyl-substituted C1-C5 alkyl groups, amino groups, and amino-substituted C1-C5 alkyl groups.

[0023] In some embodiments, N active groups of R1, R2, R3, R4, R5, and R6 are selected from vinyl groups, and R7 and R8 are selected from vinyl groups, acrylate groups, methacrylate groups, mercapto groups, and mercapto-substituted C1-C5 alkyl groups.

[0024] In some embodiments, N active groups among R1, R2, R3, R4, R5, and R6 are selected from mercapto groups and mercapto-substituted C1-C5 alkyl groups, and R7 and R8 are selected from vinyl groups.

[0025] In some embodiments, the N active groups in R1, R2, R3, R4, R5, and R6 are each independently selected from acrylate groups and methacrylate groups, and R7 and R8 are selected from vinyl groups, acrylate groups, and methacrylate groups.

[0026] In some embodiments, N is 3, and R1, R3, and R5 are active groups.

[0027] In some embodiments, the monomer represented by Formula I is selected from any of the following:

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

[0029] In some embodiments, the polymer represented by Formula II is selected from any of the following:

[0030] In some embodiments, the molar ratio of the monomer shown in Formula I to the polymer shown in Formula II is 2:N. This allows the end groups of the monomer shown in Formula I and the polymer shown in Formula II to undergo a matching reaction.

[0031] In some embodiments, the total mass fraction of the monomers shown in Formula I and the polymers shown in Formula II is 0.5%-20% based on the total mass of the gel polymer electrolyte composition.

[0032] In some embodiments, the gel polymer electrolyte composition further includes an initiator.

[0033] Secondly, this application provides a gel polymer electrolyte, which is obtained by polymerizing the gel polymer electrolyte composition of the first aspect of this application.

[0034] Thirdly, this application provides a battery cell including a gel polymer electrolyte, which is obtained by polymerizing the gel polymer electrolyte composition of the first aspect of this application.

[0035] The battery cell includes a gel polymer electrolyte obtained by polymerizing the gel polymer electrolyte composition of the first aspect of this application, thereby having a longer cycle life and storage life.

[0036] In some embodiments, the method for polymerizing the gel polymer electrolyte composition of the first aspect of this application is in-situ curing polymerization.

[0037] 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.

[0038] 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.

[0039] Sixthly, this application provides an electrical device including a battery cell according to the fifth aspect of this application. Attached Figure Description

[0040] 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.

[0041] Figure 1 is a schematic diagram of one embodiment of the battery cell of this application.

[0042] Figure 2 is an exploded view of one embodiment of the battery cell of this application.

[0043] Figure 3 is a schematic diagram of one embodiment of the battery module of this application.

[0044] Figure 4 is a schematic diagram of one embodiment of the battery pack of this application.

[0045] Figure 5 is an exploded view of an embodiment of the battery pack shown in Figure 4.

[0046] Figure 6 is a schematic diagram of one embodiment of an electrical device that uses the battery of this application as a power source.

[0047] The accompanying drawings are not necessarily drawn to scale. The reference numerals are 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 Implementation

[0048] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the gel polymer electrolyte composition, gel polymer electrolyte, battery cell, preparation method thereof, and electrical device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0049] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0050] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0051] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0052] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0053] Unless otherwise stated, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0054] Unless otherwise stated, the values ​​of the parameters mentioned in this application can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in the embodiments of this application. Unless otherwise stated, the test temperature for each parameter is 25°C.

[0055] The battery mentioned in the embodiments of this application may include one or more battery cells as a single physical module to provide higher voltage and capacity. For example, the battery mentioned in this application may include battery cells, battery modules, or battery packs.

[0056] A battery cell is the smallest unit that makes up a battery, and it can independently perform the functions of charging and discharging. A battery cell can be cylindrical, cuboid, or other shapes, and the embodiments of this application are not limited to this. Figure 1 shows a cuboid battery cell 5 as an example.

[0057] When there are multiple battery cells, they are connected in series, parallel, or mixed via a busbar. In some embodiments, the battery can be a battery module; when there are multiple battery cells, they are arranged and fixed to form a battery module. In some embodiments, the battery can be a battery pack, which includes a housing and battery cells, with the battery cells or battery modules housed within the housing. In some embodiments, the housing can be part of the vehicle's chassis structure. For example, a portion of the housing can be at least part of the vehicle's floor, or a portion of the housing can be at least part of the vehicle's crossbeams and longitudinal beams.

[0058] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0059] The battery cell includes an electrode assembly. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to this.

[0060] The battery cell may also include an outer packaging, which can be used to encapsulate electrode components and non-aqueous electrolyte. The outer packaging can be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. The outer packaging can also be a flexible package, such as a pouch-type flexible package. The material of the flexible package can be plastic, such as one or more of aluminum-plastic film, polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0061] In some embodiments, as shown in FIG2, the outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates enclosing a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 is used to cover the opening to close the receiving cavity. Electrode assemblies 52 are encapsulated in the receiving cavity. The number of electrode assemblies 52 contained in the battery cell 5 may be one or more, and can be adjusted as needed.

[0062] In some embodiments, individual battery cells can be assembled into a battery module. The number of battery cells in a battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module. Figure 3 is a schematic diagram of a battery module 4 as an example. As shown in Figure 3, in the battery module 4, multiple battery cells 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other arbitrary manner. Furthermore, the multiple battery cells 5 can be fixed in place using fasteners.

[0063] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0064] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0065] Figures 4 and 5 are schematic diagrams of a battery pack 1 as an example. As shown in Figures 4 and 5, the battery pack 1 may include a housing and multiple battery modules 4 disposed within the housing. The housing includes an upper housing 2 and a lower housing 3. The upper housing 2 covers the lower housing 3, forming a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the housing.

[0066] The insufficient cycle life and storage life of lithium metal battery cells are mainly due to severe interfacial side reactions, which continuously consume organic solvents and lithium salt anions in the non-aqueous electrolyte, as well as active lithium. In addition, conventional non-aqueous electrolytes are free-flowing, and the active reactive components in them continue to contact the lithium metal anode interface and undergo continuous side reactions, resulting in low coulombic efficiency, short cycle life, and short storage life of lithium metal battery cells.

[0067] Based on this, embodiments of this 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 battery cells.

[0068] The gel polymer electrolyte composition provided in this application includes a non-aqueous electrolyte, a monomer shown in Formula I, and a polymer shown in Formula II.

[0069] Of R1, R2, R3, R4, R5, and R6, N are active groups, and each of the N active groups is independently selected from vinyl, hydroxy, hydroxy-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, mercapto, mercapto-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, and methacrylate. The remaining (6-N) are independently selected from H, C1-C5 alkyl, C1-C5 haloalkyl, and C1-C5 oxaalkyl, and N is 3, 4, 5, or 6.

[0070] R7 and R8 are each independently selected from vinyl, hydroxy, hydroxy-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, mercapto, mercapto-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, and methacrylate, and R7 and R8 can undergo polymerization reactions with N active groups from R1, R2, R3, R4, R5, and R6.

[0071] Each time M1, M2, M3, M4, M5, and M6 appear, they are each independently selected from any one of H, halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, C1-C5 alkyl, and C1-C5 oxaalkyl, and at least one of M1, M2, M3, M4, M5, and M6 is selected from any one of halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, and amino-substituted C1-C5 alkyl.

[0072] n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n×m is 10-10000.

[0073] The gel polymer electrolyte composition provided in this application includes a monomer shown in Formula I and a polymer shown in Formula II. The monomer shown in Formula I and the polymer shown in Formula II can undergo a polymerization reaction, thereby forming a gel polymer electrolyte after polymerization. The monomer shown in Formula I and the polymer shown in Formula II form the polymer backbone of the gel polymer electrolyte after polymerization. The gel polymer electrolyte is flexible and can have good contact with the electrode interface, thereby reducing interfacial impedance.

[0074] The monomer shown in Formula I and the polymer shown in Formula II possess benzene rings, which are rigid and have a large π-bond structure, thus improving the strength of the gel polymer electrolyte. The polymer shown in Formula II also contains ether-oxygen segments, which are flexible. This allows the formed polymer backbone network to possess both rigidity and flexibility, ensuring good contact between the gel polymer electrolyte and the electrode interface during the continuous expansion and contraction of the battery cell during charge-discharge cycles. Simultaneously, it prevents the gel polymer electrolyte from breaking down, thereby contributing to a long cycle life and storage life of the battery cell. The ether-oxygen segments in the polymer shown in Formula II have good affinity for non-aqueous electrolytes, binding the non-aqueous electrolyte within the polymer backbone network and preventing its free flow. This reduces the side reactions that continuously consume active lithium at the negative electrode interface caused by unstable organic solvents and lithium salt anions in the non-aqueous electrolyte. Furthermore, it facilitates the long-term stable wetting of the electrode assembly by the non-aqueous electrolyte, reducing localized drying problems and thus improving the cycle life of the battery cell.

[0075] In the polymer shown in Formula II, at least one of M1, M2, M3, M4, M5, and M6 is selected from any one of halogen atoms, C1-C5 haloalkyl groups, hydroxyl groups, hydroxyl-substituted C1-C5 alkyl groups, amino groups, and amino-substituted C1-C5 alkyl groups. These groups can form strong hydrogen bond interactions with organic solvents and lithium salt anions in non-aqueous electrolytes. Through hydrogen bond interactions, organic solvents and lithium salt anions can be anchored, preventing them from migrating freely with lithium ions to the lithium metal anode interface and causing side reactions that consume active lithium.

[0076] n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n×m is 10-10000. This allows the formed polymer skeleton network to have 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 charge and discharge cycles. At the same time, it can make the gel polymer electrolyte less prone to breakage, thereby enabling the battery cell to have a long cycle life and storage life.

[0077] Therefore, the gel polymer electrolyte composition provided in this application embodiment can reduce interfacial side reactions and improve the cycle life and storage life of the battery cell when used in a battery cell.

[0078] n is an integer between 1 and 1000, for example, it 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 any range of the above values.

[0079] Optionally, 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.

[0080] Within the aforementioned range, the polymer shown in Formula II can possess both flexibility and a suitable ratio of ether oxygen segments to benzene rings, thereby enabling the gel polymer electrolyte to have better mechanical properties.

[0081] m is an integer between 1 and 1000, for example, it 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 any range of the above values.

[0082] Optionally, 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.

[0083] Within the above range, the formed gel polymer electrolyte can have a suitable skeleton space, so that the gel polymer electrolyte can completely accommodate the non-aqueous electrolyte even when the mass fraction of the polymer skeleton is low, thus achieving good ion transport characteristics.

[0084] n×m is 10-10000, for example, it can be 10000, 8000, 6000, 5000, 4000, 3000, 2500, 2000, 1500, 1000, 500, 200, 100, 50, 10, or any of the above values.

[0085] Optionally, in some embodiments, n×m can be 50-5000, 50-4000, 50-3000, 50-2500, 50-2000, 100-4000, 100-3000, 100-2500, or 100-2000.

[0086] Within the above range of n×m, battery cells can have longer cycle life and storage life.

[0087] In some embodiments, the weight-average molecular weight of the polymer shown in Formula II is 75 million to 650,000, for example, it can be 75 million, 80 million, 10,000, 20,000, 40,000, 80,000, 100,000, 120,000, 160,000, 180,000, 200,000, 220,000, 240,000, 280,000, 320,000, 360,000, 400,000, 450,000, 650,000, or any combination of the above values.

[0088] Optionally, the weight-average molecular weight of the polymer shown in Formula II is 75 million to 360,000, 75 million to 240,000, 75 million to 220,000, 75 million to 200,000, 75 million to 180,000, or 75 million to 160,000.

[0089] The polymer shown in Formula II has a weight-average molecular weight within the above range, which can enable the battery cell to have a longer cycle life and storage life.

[0090] In some embodiments, the polymerization reactions of R7 and R8 with N active groups among R1, R2, R3, R4, R5, and R6 include condensation polymerization and addition polymerization.

[0091] In some embodiments, the N active groups in R1, R2, R3, R4, R5, and R6 may be the same.

[0092] In some embodiments, R7 and R8 can be the same.

[0093] In some embodiments, the N active groups among R1, R2, R3, R4, R5, and R6 can be selected from hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, and amino-substituted C1-C5 alkyl, and R7 and R8 can be selected from isocyanate and methylene isocyanate. Optionally, the N active groups among R1, R2, R3, R4, R5, and R6 can be selected from hydroxyl and amino, and R7 and R8 can be selected from isocyanate and methylene isocyanate.

[0094] In some embodiments, the N active groups among R1, R2, R3, R4, R5, and R6 can be independently selected from isocyanate groups and methylene isocyanate groups, and R7 and R8 can be selected from hydroxyl groups, hydroxyl-substituted C1-C5 alkyl groups, amino groups, and amino-substituted C1-C5 alkyl groups. Optionally, the N active groups among R1, R2, R3, R4, R5, and R6 can be independently selected from isocyanate groups and methylene isocyanate groups, and R7 and R8 can be selected from hydroxyl groups and amino groups.

[0095] The polymerization reactions of R7 and R8 with N active groups from R1, R2, R3, R4, R5, and R6 are condensation polymerization reactions. Condensation polymerization does not require the addition of an initiator and does not cause other side reactions. Furthermore, the condensation polymerization of hydroxyl groups with isocyanate groups produces polyurethane, and the condensation polymerization of amine groups with isocyanate groups produces polyurea. Polyurethane and polyurea possess dynamic hydrogen bond structures, which are beneficial for forming polymer network structures with flexible and self-healing properties. This polymer network structure exhibits good positive and negative electrode stability and structural strength, contributing to the good mechanical and electrochemical stability of the gel polymer electrolyte during long-term cycling of the battery cell.

[0096] In some embodiments, N active groups in R1, R2, R3, R4, R5, and R6 may be selected from vinyl groups, and R7 and R8 may be selected from vinyl groups, acrylate groups, methacrylate groups, mercapto groups, and mercapto-substituted C1-C5 alkyl groups.

[0097] In some embodiments, the N active groups among R1, R2, R3, R4, R5, and R6 may be selected from mercapto or mercapto-substituted C1-C5 alkyl groups, and R7 and R8 may be selected from vinyl groups.

[0098] In some embodiments, the N active groups in R1, R2, R3, R4, R5, and R6 can be independently selected from acrylate groups and methacrylate groups, and R7 and R8 can be selected from vinyl groups, acrylate groups, and methacrylate groups.

[0099] In some embodiments, N can be 3 or 4.

[0100] In some embodiments, N can be 3, and R1, R3, and R5 can be active groups. Optionally, N can be 3, R1, R3, and R5 can be active groups, and R2, R4, and R6 can be selected from H.

[0101] In some embodiments, the monomer represented by Formula I may be selected from any of the following:

[0102] In some embodiments, one or two of M1, M2, M3, M4, M5, and M6 may be selected from any one of halogen atoms, C1-C5 haloalkyl groups, hydroxyl groups, hydroxyl-substituted C1-C5 alkyl groups, amino groups, and amino-substituted C1-C5 alkyl groups. Optionally, one or two of M1, M2, M3, M4, M5, and M6 may be selected from any one of halogen atoms, hydroxyl groups, and amino groups.

[0103] In some embodiments, at least one of M1, M2, M3, M4, M5, and M6 may be selected from hydroxyl groups and any of the C1-C5 alkyl groups substituted with hydroxyl groups. The hydroxyl group can form strong hydrogen bonds with the organic solvent in the non-aqueous electrolyte and with oxygen, fluorine, nitrogen, and other atoms in the lithium salt anion, thereby better anchoring the organic solvent and the lithium salt anion.

[0104] Optionally, one or two of M1, M2, M3, M4, M5, and M6 may be selected from hydroxyl groups or hydroxyl-substituted C1-C5 alkyl groups.

[0105] Alternatively, one or two of M1, M2, M3, M4, M5, and M6 may be selected from hydroxyl groups, and the rest may be selected from H.

[0106] One or two of M1, M2, M3, M4, M5, and M6 are selected from hydroxyl groups, which can reduce the consumption of active lithium during the solid electrolyte interphase (SEI) film formation process.

[0107] In some embodiments, the polymer represented by Formula II may be selected from any of the following:

[0108] In some embodiments, the molar ratio of the monomer shown in Formula I to the polymer shown in Formula II can be 2:N. This allows the monomer shown in Formula I to undergo a matching reaction with the end groups of the polymer shown in Formula II.

[0109] In some embodiments, based on the total mass of the gel polymer electrolyte composition, the total mass fraction of the monomer shown in Formula I and the polymer shown in Formula II can be 0.5%-20%, for example, it 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 any range of the above values.

[0110] Optionally, the total mass fraction of the monomer shown in Formula I and the polymer shown in Formula II can be 1%-15%, 2%-10%, or 3%-8%.

[0111] In some embodiments, the gel polymer electrolyte composition may further include an initiator.

[0112] Optionally, the mass of the initiator can be 0.1%-10% of the total mass of the monomer shown in Formula I and the polymer shown in Formula II. An appropriate amount of initiator is beneficial for the full polymerization of the monomer shown in Formula I and the polymer shown in Formula II.

[0113] Optionally, the initiator may include one or more of azo initiators and peroxide initiators, for example, one or more of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (AMVN), acetyl peroxide, and hydrogen peroxide.

[0114] Non-aqueous electrolytes include lithium salts and organic solvents. Non-aqueous electrolytes can be high-concentration electrolytes or locally high-concentration electrolytes, which can further improve the cycle life and storage life of battery cells.

[0115] In some embodiments, the lithium salt may include, but is not limited to, one or more of lithium bis(trifluoromethyl)sulfonylimide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium bis(trifluoromethyl)sulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiOTF), lithium dioxolaneborate (LiBOB), lithium difluorooxolaneborate (LiDFOB), lithium difluorodioxolane phosphate, and lithium tetrafluorooxolane phosphate.

[0116] Optionally, the lithium salt may include lithium bisfluorosulfonylimide (LiFSI). This lithium salt can decompose on the negative electrode surface to form an inorganic fluorine-rich SEI film component, which is beneficial to the long cycle life of the battery cell; at the same time, this lithium salt also has good oxidation stability, which can support the cycling of the battery cell under high voltage.

[0117] In some embodiments, the lithium salt concentration of the non-aqueous electrolyte can be 0.5 mol / L to 4 mol / L, for example, it can be 0.5 mol / L, 1 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, or any range of the above values. Optionally, the lithium salt concentration of the non-aqueous electrolyte can be 1.5 mol / L to 3.5 mol / L, or 2 mol / L to 3.5 mol / L.

[0118] In some embodiments, the organic solvent may include ether solvents. Ether solvents may include one or more of chain ether solvents and cyclic ether solvents.

[0119] Chain ether solvents may include, but are not limited to, one or more of diethyl ether, dipropyl ether, ethylpropyl ether, methyl butyl ether, dibutyl ether, ethyl butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol diethyl ether, propylene glycol diethyl ether, butanediol dimethyl ether, butanediol diethyl ether, butanediol diethyl ether, butanediol diethyl ether. Cyclic ether solvents may include, but are not limited to, one or more of tetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxopentane, tetrahydropyran, 1,3-dioxane, and 1,4-dioxane.

[0120] Optionally, the organic solvent may include one or both of ethylene glycol dimethyl ether (DME) and propylene glycol dimethyl ether (DMP). These organic solvents exhibit good lithium salt solubility and stability at both positive and negative electrodes, which is beneficial for rapid ion conduction and stability at the positive and negative electrode interfaces.

[0121] In some embodiments, the non-aqueous electrolyte may further include a diluent. The diluent may include, but is not limited to, 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, One or more of the following: 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, perfluoroisopropylmethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, ethyl-1,1,2,2-tetrafluoroethyl ether, ethyl-2,2,2-tetrafluoroethyl ether, and bis(1,1,2,2-tetrafluoroethyl) ether.

[0122] Optionally, the diluent may include one or both of benzene and 1,2-bis(difluoromethoxy)ethane. This type of diluent has low viscosity, low molecular weight, and high stability, which can improve the interfacial stability of the positive and negative electrodes, while simultaneously reducing the viscosity and increasing the conductivity of the non-aqueous electrolyte, thereby enhancing the ion transport characteristics of the polymer electrolyte formed by polymerization.

[0123] In some embodiments, the non-aqueous electrolyte may include both an organic solvent and a diluent, and the mass fraction of the organic solvent may be 10%-80% and the mass fraction of the diluent may be 20%-90%, based on the total mass of the organic solvent and the diluent being 100%.

[0124] Optionally, the mass fraction of the organic solvent may be less than the mass fraction of the diluent.

[0125] Optionally, based on the total mass of the organic solvent and diluent as 100%, the mass fraction of the organic solvent can be 20%-40%, and the mass fraction of the diluent can be 60%-80%.

[0126] This application also provides a gel polymer electrolyte, which is obtained by polymerizing the above-described gel polymer electrolyte composition.

[0127] This application also provides a battery cell. The battery cell includes a gel polymer electrolyte, which is obtained by polymerizing the above-described gel polymer electrolyte composition.

[0128] The battery cell provided in this application includes a gel polymer electrolyte obtained by polymerizing the above-mentioned gel polymer electrolyte composition. Its polymer backbone structure can bind the non-aqueous electrolyte, thereby reducing interfacial side reactions, reducing the consumption of non-aqueous electrolyte and active lithium, and also having a longer cycle life and storage life.

[0129] Optionally, the polymerization method is in-situ curing polymerization.

[0130] The polymer backbone structure of gel polymer electrolytes can be obtained through methods such as NMR and FT-IR. For example, after disassembling a battery cell, a gel polymer electrolyte sample from its residual space is taken and injected into an NMR sample tube or FT-IR sample stage for testing. The resulting spectrum is compared with a standard spectrum to determine the specific structure, and then the polymer backbone structure type is obtained through comprehensive analysis.

[0131] The skeletal structure of the gel polymer electrolyte and the mass fraction of the bound non-aqueous electrolyte can be obtained by freeze-drying. For example, after disassembling the battery cell, a gel polymer electrolyte sample from the residual space is taken, and the sample mass m1 is weighed. This sample is then placed in a freeze dryer for freeze-drying. After freeze-drying, the remaining sample mass m2 is weighed. m1-m2 represents the mass of the organic solvent in the non-aqueous electrolyte. The freeze-dried sample is then thoroughly washed and dried using ethylene glycol dimethyl ether. The dried sample is weighed again, and its mass m3 represents the mass of the polymer skeleton. m2-m3 represents the mass of the lithium salt. This allows the determination of the mass fractions of different components in the gel polymer electrolyte, such as the polymer skeleton, non-aqueous electrolyte, organic solvent, and lithium salt.

[0132] A single battery cell also includes a positive electrode, a negative electrode, and a separator.

[0133] The battery cells provided in the embodiments of this application may include lithium metal battery cells and lithium metal battery cells without negative electrodes.

[0134] Taking a lithium metal battery cell as an example, the negative electrode may include a negative current collector and a lithium metal layer disposed on at least one surface of the negative current collector. The lithium metal layer includes elemental lithium or an alloy formed by lithium metal and other metals or metalloids. Optionally, other metallic elements include one or more of Sn, Zn, Al, Mg, Ag, Au, Ga, In, and Pt. Optionally, other metalloid elements include one or more of B, C, and Si.

[0135] A negative electrode-free lithium metal battery cell typically refers to a battery cell in which no negative electrode active material layer is actively formed on the negative electrode side during the battery cell manufacturing process. For example, the negative electrode active material layer is not formed at the negative electrode through processes such as coating or deposition. During the first charge, ions gain electrons on the negative electrode side and deposit on the surface of the negative electrode current collector to form a metallic phase. During discharge, the metal can transform into metal ions and return to the positive electrode, achieving cyclic charging and discharging. Compared to other battery cells, a negative electrode-free lithium metal battery cell can achieve a higher energy density due to the absence of a negative electrode active material layer. In some embodiments, to improve the performance of the battery cell, some conventional materials that can be used as negative electrode active materials, such as carbon materials, can also be placed on the negative electrode side of the negative electrode-free lithium metal battery cell. Although these materials have a certain capacity, because their content is small and they are not used as the main negative electrode active material in the battery cell, the battery cell constructed in this way can still be regarded as a negative electrode-free lithium metal battery cell. The CB value of a cathodeless lithium metal battery cell is typically very small; for example, in some embodiments, the CB value of a cathodeless 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 divided by the capacity per unit area of ​​the positive electrode in the battery cell. Because a cathodeless lithium metal battery cell contains little or no negative electrode active material, the capacity per unit area of ​​the negative electrode is small, resulting in a very small CB value, typically less than or equal to 0.1.

[0136] Taking a single lithium metal battery cell without a negative electrode as an example, the negative electrode sheet may include a negative current collector but does not include a lithium metal layer. During the charge and discharge cycle of a single lithium metal battery cell without a negative electrode, lithium from the positive electrode will be deposited and stripped off in the form of lithium metal on the negative electrode side.

[0137] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. Examples of metal foils include copper foil, copper alloy foil, nickel foil, and nickel alloy foil. The composite current collector may include a polymer substrate and a metal material layer formed on at least one surface of the polymer substrate. Examples of metal materials include, but are not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymer substrates include, but are not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0138] In some embodiments, the positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer comprising a positive active material. For example, the positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0139] The positive electrode active material includes materials capable of lithium extraction and insertion. Optionally, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites, and their respective modified compounds.

[0140] The modified compounds for the above-mentioned positive electrode active materials can be obtained by doping and / or surface coating of the positive electrode active materials.

[0141] In some embodiments, to further improve the energy density of a single battery cell, the positive electrode active material may include materials of the general formula Li. a Ni b Co c M d O e A f One or more of lithium transition metal oxides and their modified compounds. 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.

[0142] In some embodiments, as an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), LiNi 0.96 Co 0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 O2, LiFePO4, LiMnPO4, and one or more of their respective modified compounds.

[0143] During the charging and discharging process, lithium (Li) undergoes insertion / extraction and consumption within a single battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this application, the molar Li content represents the initial state of the material, i.e., the state before material addition. As the positive electrode active material is applied to the battery cell, the molar Li content changes after charge-discharge cycles. Similarly, in the examples of positive electrode active materials in this application, the molar O content is only a theoretical value. Lattice oxygen release causes changes in the molar O content, leading to fluctuations in the actual molar O content.

[0144] In some embodiments, the positive electrode film may optionally include a positive electrode conductive agent. As an example, the positive electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0145] In some embodiments, the positive electrode film layer may optionally include a positive electrode binder. As an example, the positive electrode binder may include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0146] In some embodiments, the positive current collector may be a metal foil or a composite current collector. An example of a metal foil is aluminum foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0147] The positive electrode film can be formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is typically formed by dispersing positive electrode active materials, positive electrode conductive agents, positive electrode binders, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0148] A separator can be disposed between the positive and negative electrode plates, primarily serving to prevent internal short circuits. This application does not impose any particular limitation on the type of separator; any known porous membrane with good chemical and mechanical stability can be selected. In some embodiments, the separator material may include, but is not limited to, one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and polyimide. The separator can be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different.

[0149] This application also provides a method for preparing a single battery cell.

[0150] The preparation method includes the following steps: providing a battery cell to be injected with electrolyte, mixing the above-mentioned 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 it 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.

[0151] In some embodiments, the heating temperature can be 60°C-80°C.

[0152] In some embodiments, the heating time can be 6h-24h.

[0153] In some embodiments, the precursor solution can be heated during the static soaking process to allow the precursor solution to solidify and polymerize in situ inside the battery cell to form a gel polymer electrolyte.

[0154] Optionally, the precursor solution can be allowed to stand and soak at 20℃-45℃ for 2h-12h to allow the precursor solution to soak the battery cell to be injected; then it can be allowed to stand and soak at 60℃-80℃ for 6h-24h to allow the precursor solution to solidify and polymerize in situ inside the battery cell to form a gel polymer electrolyte.

[0155] The preparation method of the battery cell to be injected with electrolyte is well 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. The electrode assembly is placed in an outer packaging and dried to obtain the battery cell to be injected with electrolyte.

[0156] Electrical appliances

[0157] This application also provides an electrical device, which includes the battery provided in this application embodiment. The battery can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device can be, but is not limited to, mobile devices (such as mobile phones, tablets, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0158] Electrical devices can choose the type of battery according to their usage needs, such as individual battery cells, battery modules, or battery packs.

[0159] Figure 6 is a schematic diagram of an example electrical device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0160] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source.

[0161] Example

[0162] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. 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 by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0163] In the following embodiments and comparative examples, for the sake of simplicity, the monomers shown in Formula I are numbered as follows.

[0164] In the following examples and comparative examples, for the sake of simplicity, the polymers shown in Formula II are numbered as follows.

[0165] This application provides an exemplary method for preparing the polymer represented by Formula II, numbered 18. Other polymers represented by Formula II in this application can be prepared by referring to this exemplary method. Based on the exemplary method for preparing the polymer represented by Formula II, those skilled in the art can readily obtain specific methods for implementing each synthetic step from relevant scientific literature or standard textbooks in the field. Unless otherwise specified, commercially available or literature-known compounds are used as raw materials for synthesis. Those skilled in organic synthesis will recognize that the nature and order of the proposed synthetic steps can be modified to optimize the generation of the compounds described in this application.

[0166] The process described in the embodiments of this application can be monitored using any suitable method known in the art. For example, product formation can be achieved through spectroscopic means such as nuclear magnetic resonance spectroscopy (NMR, e.g.) 1 H, 13 C or 19 F) Infrared spectroscopy (IR), mass spectrometry (MS), and X-ray photoelectron spectroscopy (XPS) are used for monitoring.

[0167] For example, the method for synthesizing the polymer shown in Formula II, number 18, is as follows.

[0168] 16.42 g (0.1 mol) of 2-(2,3-dihydrobenzofuran-6-yl)ethanol-1-ol was dissolved in 60 mL of acetonitrile. After stirring and cooling to 0 °C, 2 mol / L hydrochloric acid solution was added dropwise to adjust the pH to 4–5. After the addition was complete, the mixture was kept at 45 °C for 15 min and then stirred for 3 h. After the reaction was complete, the mixture 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 the mixture was stirred for 1 h. Then, iodomethane (CH3I, 17.03 g, 0.12 mol) was added dropwise. After the addition was complete, the temperature was raised to room temperature (approximately 25 °C) and stirred for 3 h. After the reaction was complete, the organic solvent acetonitrile was removed by vacuum concentration. The mixture was extracted with dichloromethane (50 mL × 3), washed with saturated brine, and then dried over anhydrous sodium sulfate. After filtration, the organic phase was concentrated under reduced pressure to remove the organic solvent dichloromethane (DCM) to obtain the crude product. The crude product was then subjected to V... 乙酸乙酯 :V 石油醚 Recrystallization at a ratio of 1:10 yielded 12.02 g of white solid 1, which was set aside for later use.

[0169] 1 H NMR (DMSO-d6, 400MHz), 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, 100MHz), 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.

[0170] Compound 1 (5 g, 25.48 mmol) was dissolved in 50 mL of N,N-dimethylformamide (DMF). The solution was stirred and cooled to -20°C to -10°C. Then, 2 mol / L sodium hydroxide solution was added dropwise to adjust the pH to 10–12. After the addition was complete, ethylene glycol (0.79 g, 12.74 mmol) was added dropwise. Finally, methylamine (2.40 g, 50.96 mmol) was added dropwise. The mixture was stirred for 30 min, then heated to 45°C and stirred for 3 h. After the reaction was complete, the reaction solution was dialyzed into a dialysis bag (5 kDa) until the water outside the bag was neutral. Finally, 6.12 g (74.73% yield) of polymer 2 was obtained by freeze-drying. 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.

[0171] 4g of polymer 2 was dissolved in 30mL of N,N-dimethylformamide (DMF). After stirring and cooling to 0℃, BBr3 / DCM solution was added dropwise until no methyl peak with a shift of 3.73 was observed in the NMR spectrum. After the addition was complete, crushed ice was added to quench the reaction. The reaction solution was then injected into a dialysis bag (5kDa) for dialyzing until the water outside the dialysis bag was neutral. Finally, 2.2g of polymer was obtained by freeze-drying, which is polymer II represented by formula number 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.

[0172] Example 1

[0173] (1) Preparation of lithium metal battery cells to be injected with liquid electrolyte

[0174] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 98:1:1 and added to the solvent N-methylpyrrolidone (NMP). The mixture was stirred until the system was homogeneous, yielding a positive electrode slurry with a solid content of approximately 70%. The positive electrode slurry was then subjected to a reaction at approximately 12.5 mg / cm³. 2 The loading amount is evenly coated on both surfaces of the positive current collector aluminum foil, dried, transferred to an oven for further drying, and then cut into 40mm×50mm rectangles as positive electrode sheets for later use.

[0175] Cut the polyethylene porous membrane into rectangles of 45mm × 55mm to serve as a release liner.

[0176] A 50μm lithium foil is rolled onto a 12μm copper foil and then cut into 41mm×51mm rectangles to serve as negative electrode sheets for later use.

[0177] Take a cut positive electrode sheet and match it with two cut negative electrode sheets, separate them with the aforementioned separator, and wrap them in an aluminum-plastic film bag to form a lithium metal battery cell to be injected with liquid.

[0178] (2) Preparation of non-aqueous electrolyte

[0179] Ethylene glycol dimethyl ether (DME) and 1,2-bis(difluoromethoxy)ethane were mixed in a mass ratio of 3:7 to form a solvent stock solution; then 2.805g of lithium bisfluorosulfonylimide (LiFSI) was added to 5ml of the solvent stock solution and stirred thoroughly to form a colorless and transparent non-aqueous electrolyte.

[0180] (3) Preparation of finished lithium metal battery cells

[0181] The monomer shown in Formula I (numbered 1) and the polymer shown in Formula II (numbered 1) are premixed at a molar ratio of 2:3. An appropriate amount is then injected into the previously prepared non-aqueous electrolyte to form a precursor solution. The total mass fraction of the monomer shown in Formula I and the polymer shown in Formula II in the precursor solution is 5%. 0.3g of the precursor solution is injected into the prepared lithium metal battery cell to be injected. The cell is then vacuum-sealed in an aluminum-plastic film bag and allowed to stand at 25°C for 6 hours, followed by standing at 60°C for 12 hours. This allows the monomer shown in Formula I and the polymer shown in Formula II to complete the in-situ polymerization and solidification reaction, forming a gel polymer electrolyte, thus obtaining the finished lithium metal battery cell. The rated capacity of the lithium metal battery cell is 70mAh.

[0182] Examples 2 to 26

[0183] The preparation method of the finished lithium metal battery cell is the same as in Example 1, except that one or more of the following are different: the type of monomer shown in Formula I, the type of polymer shown in Formula II, and the molar ratio of the monomer shown in Formula I to the polymer shown in Formula II. Specific parameters are detailed in Table 1. Optionally, depending on the reaction type between the monomer shown in Formula I and the polymer shown in Formula II, an initiator, such as AIBN at 0.05% of the total mass of the monomer shown in Formula I and the polymer shown in Formula II, can be added to the precursor solution.

[0184] Comparative Example 1

[0185] (1) Preparation of lithium metal battery cells to be injected with liquid electrolyte

[0186] Same as Example 1.

[0187] (2) Preparation of non-aqueous electrolyte

[0188] Same as Example 1.

[0189] (3) Preparation of finished lithium metal battery cells

[0190] 0.3g of non-aqueous electrolyte was injected into the prepared battery cell, and then the aluminum-plastic film bag was vacuum heat-sealed. After standing at 25°C for 6 hours, it was transferred to 60°C and stood for 12 hours to obtain the finished lithium metal battery cell. The rated capacity of the lithium metal battery cell is 70mAh.

[0191] Comparative Examples 2 to 3

[0192] The preparation method of the finished lithium metal battery cell is the same as that in Example 1, except that the type of polymer shown in Formula II is different. For specific parameters, please refer to Table 1.

[0193] Cyclic performance test

[0194] Take the prepared lithium metal battery cell and set the ambient temperature to 25℃. Charge it at a constant current of 0.2C (14mA) until the cutoff voltage of 4.3V is reached. Then, continue charging at a constant voltage of 4.3V until the current decays to 0.1C (7mA). Then, discharge it at a constant current of 1C (70mA) to 2.8V to obtain the first discharge capacity. Repeat the above charge-discharge cycle and record the discharge capacity after each cycle. When the discharge capacity decays to 80% of the first discharge capacity, the lithium metal battery cell is considered to have reached the end of its lifespan. Record the number of cycles the lithium metal battery cell has undergone at this point as the cycle life of the lithium metal battery cell.

[0195] High-temperature storage performance test

[0196] Take the prepared lithium metal battery cell and set the ambient temperature to 25℃. Charge it with a constant current of 0.2C (14mA) until the cutoff voltage of 4.3V is reached. Then continue charging with a constant voltage of 4.3V until the current decreases to 0.1C (7mA). Then discharge it with a constant current of 1C (70mA) to 2.8V to obtain the initial capacity. Then charge it with a constant current of 0.2C (14mA) until the cutoff voltage of 4.3V is reached. Then continue charging it with a constant voltage of 4.3V until the current decreases to 0.1C (7mA). At this point, the lithium metal battery cell is fully charged. Transfer the fully charged lithium metal battery cell to a 60℃ constant temperature chamber and store it for one month. After the temperature of the lithium metal battery cell drops to 25℃, discharge it with a constant current of 1C (70mA) to 2.8V. Then discharge it with a constant current of 0.2C (14mA) to 2.8V. After charging at a constant current of 0.2C (14mA) to reach the cutoff voltage of 4.3V, continue charging at a constant voltage of 4.3V until the current decreases to 0.1C (7mA). Then, discharge at a constant current of 1C (70mA) to 2.8V. This cycle capacity is recorded as the recovery capacity. Then, charge again at a constant current of 0.2C (14mA) to reach the cutoff voltage of 4.3V, and continue charging at a constant voltage of 4.3V until the current decreases to 0.1C (7mA). At this point, the lithium metal battery cell is fully charged. Transfer the fully charged lithium metal battery cell to a 60°C constant temperature chamber and store it for one month. Repeat this cycle until the recovery capacity obtained using the above method decreases to 80% of the initial capacity. The total storage time experienced at this point (in months) is taken as the high-temperature storage life of the lithium metal battery cell. The larger this value, the better the high-temperature stability of the lithium metal battery cell.

[0197] Table 1

[0198] The test results from Examples 1 to 26 and Comparative Example 1 show that the cycle life and storage life of lithium metal battery cells using gel polymer electrolytes are superior to those using non-aqueous electrolytes (i.e., the lithium metal battery cell of Comparative Example 1). This is because the gel polymer electrolyte encapsulates and anchors the highly reactive organic solvents and lithium salt anions in the non-aqueous electrolyte, thereby preventing the non-aqueous electrolyte from flowing freely and reducing its reduction at the lithium metal anode interface. This reduces the consumption of active lithium and improves the cycle life and storage life of the metal battery cell.

[0199] The test results from Examples 1 to 14 show that different n and / or m, different ether oxygen atom contents, and different benzene ring structure contents in the polymers shown in Formula II result in different effects on improving the cycle life and storage life of lithium metal battery cells. The polymer shown in Formula II of Comparative Example 2 has an excessively large molecular weight. The resulting gel polymer electrolyte has almost no flexibility and is prone to crystallization, exhibiting poor adhesion between the gel polymer electrolyte and the electrode interface, and poor ion transport characteristics.

[0200] The test results of Examples 1, 15 to 25 and Comparative Example 3 show that by having at least one of M1, M2, M3, M4, M5 and M6 form hydrogen bonds with organic solvents and lithium salt anions in the non-aqueous electrolyte, lithium metal battery cells can have good cycle life and storage life.

[0201] The test results from Examples 1, 15 to 25 also show that by further optimizing the structure of the monomer shown in Formula I and the polymer shown in Formula II, the cycle life and storage life of lithium metal battery cells can be further improved.

[0202] The test results of Examples 1 and 26 show that by optimizing the molar ratio of the monomer shown in Formula I and the polymer shown in Formula II, the end groups of the monomer shown in Formula I and the polymer shown in Formula II can be matched and reacted, thereby further improving the cycle life and storage life of lithium metal battery cells.

[0203] Examples 2-1 to 2-4

[0204] Except for the difference in the total mass content of the monomer shown in Formula I and the polymer shown in Formula II in the precursor solution, the preparation method of the lithium metal battery cell is the same as in Example 1.

[0205] Table 2

[0206] The test results above show that the total mass fraction of the monomer shown in Formula I and the polymer shown in Formula II in the precursor liquid are different, resulting in different cycle life and storage performance of lithium metal battery cells.

[0207] Examples 3-1 to 3-18 and Comparative Example 4

[0208] Except for the different composition of the non-aqueous electrolyte in the precursor solution, the preparation method of the lithium metal battery cell is the same as in Example 1.

[0209] For the sake of simplicity, the non-aqueous electrolytes are numbered as follows in the following examples and comparative examples.

[0210] Table 3

[0211] The test results above show that the composition of non-aqueous electrolytes can also affect the cycle life of lithium metal battery cells.

[0212] Comparative Example 4 uses ester solvents, which have high reactivity with the lithium metal anode of lithium metal battery cells and will cause severe active lithium corrosion during cycling, resulting in poor cycle life and storage life of lithium metal battery cells.

[0213] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A gel polymer electrolyte composition, comprising: Non-aqueous electrolyte, monomers shown in Formula I and polymers shown in Formula II, Of R1, R2, R3, R4, R5, and R6, N are active groups, and each of the N active groups is independently selected from vinyl, hydroxy, hydroxy-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, mercapto, mercapto-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, and methacrylate. The remaining (6-N) are independently selected from H, C1-C5 alkyl, C1-C5 haloalkyl, and C1-C5 oxaalkyl, and N is 3, 4, 5, or 6. R7 and R8 are each independently selected from vinyl, hydroxy, hydroxy-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, mercapto, mercapto-substituted C1-C5 alkyl, isocyanate, methylene isocyanate, acrylate, and methacrylate, and R7 and R8 can undergo polymerization reactions with N active groups from R1, R2, R3, R4, R5, and R6; Each time M1, M2, M3, M4, M5, and M6 appear, they are independently selected from any one of H, halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, amino-substituted C1-C5 alkyl, C1-C5 alkyl, and C1-C5 oxaalkyl, and at least one of M1, M2, M3, M4, M5, and M6 is selected from any one of halogen atom, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, and amino-substituted C1-C5 alkyl. n is an integer between 1 and 1000, m is an integer between 1 and 1000, and n×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×m is 100-4000.

3. The gel polymer electrolyte composition according to any one of claims 1-2, wherein, The weight-average molecular weight of the polymer shown in Formula II is 75 million to 360,000.

4. The gel polymer electrolyte composition according to any one of claims 1-3, wherein, The polymerization reactions of R7 and R8 with N active groups from R1, R2, R3, R4, R5, and R6 include condensation polymerization and addition polymerization.

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

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

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

8. The gel polymer electrolyte composition according to any one of claims 1-7, wherein, The monomer shown in Formula I is selected from any one of the following:

9. The gel polymer electrolyte composition according to any one of claims 1-8, wherein, One or two of M1, M2, M3, M4, M5, and M6 are selected from any one of halogen atoms, C1-C5 haloalkyl, hydroxyl, hydroxyl-substituted C1-C5 alkyl, amino, and amino-substituted C1-C5 alkyl.

10. The gel polymer electrolyte composition according to any one of claims 1-9, wherein, The polymer shown in Formula II is selected from any one of the following:

11. The gel polymer electrolyte composition according to any one of claims 1-10, wherein, The molar ratio of the monomer shown in Formula I to the polymer shown in Formula II is 2:N.

12. The gel polymer electrolyte composition according to any one of claims 1-11, wherein, Based on the total mass of the gel polymer electrolyte composition, the total mass fraction of the monomer shown in Formula I and the polymer shown in Formula II is 0.5%-20%.

13. The gel polymer electrolyte composition according to any one of claims 1-12, wherein, The gel polymer electrolyte composition also includes an initiator.

14. A gel polymer electrolyte, wherein, It is obtained by polymerizing the gel polymer electrolyte composition according to any one of claims 1-13.

15. A single battery cell, wherein, The invention includes a gel polymer electrolyte, which is obtained by polymerizing the gel polymer electrolyte composition according to any one of claims 1-13.

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

17. A method for preparing a single battery cell, comprising the following steps: A battery cell to be injected with electrolyte is provided, and a precursor solution is obtained by mixing the gel polymer electrolyte composition according to any one of claims 1-13. The obtained precursor solution is injected into the battery cell to be injected with electrolyte, and then the precursor solution is treated under heating conditions to solidify and polymerize in situ inside the battery cell to form a gel polymer electrolyte, thereby obtaining the battery cell.

18. A battery comprising a battery cell according to any one of claims 15-16 or a battery cell prepared by the preparation method according to claim 17.

19. An electrical device comprising the battery of claim 18.

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