Battery monomer, battery and electric device

Abstract

The invention discloses a battery monomer, a battery and a power utilization device, the battery monomer comprises an electrolyte, the electrolyte comprises an electrolyte salt and a solvent, the solvent comprises a fluorosulfonamide solvent represented by a formula I, R1 is oxaalkylene with a C atom number of 2-7, R1 is connected with an N atom to form a 4-8-membered ring, and R2 is a hydrogen atom. The number of O atoms on a ring of a ring structure formed by connecting R1 and N atoms is 1-3; and R2 is F atom or trifluoromethyl. The cycle life of the battery can be prolonged, and the gas production rate of the battery is reduced. # imgabs0 #

Description

Technical Field

[0001] The present application relates to a battery cell, a battery and an electrical device. Background Art

[0002] With the realization of application scenarios such as long-range electric vehicles, drones, and electric aircraft, the demand for high-energy-density batteries is increasing. The energy density of traditional lithium-ion batteries with carbon-based materials as negative electrodes can no longer meet the demand, so a battery system with higher energy density is needed. Lithium metal batteries have attracted widespread attention due to their high energy density, but the cycle life of lithium metal batteries is relatively short, which affects their commercialization. At the same time, the reliability of lithium metal batteries will also affect their commercialization. The electrolyte currently used in lithium metal batteries usually has a large gas production, which affects the reliability of lithium metal batteries. The above statements are only used to provide background technical information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0003] The present application provides a battery cell, a battery, and an electrical device, which can increase the cycle life of the battery and reduce the gas production of the battery.

[0004] In a first aspect, the present application provides a battery cell, wherein the battery cell includes an electrolyte, and the electrolyte includes an electrolyte salt and a solvent.

[0005] The solvent includes a fluorosulfonamide solvent represented by formula I,

[0006]

[0007] R1 is an oxaalkylene group having 2 to 7 carbon atoms, R1 is connected to the N atom to form a 4- to 8-membered ring, and the number of O atoms on the ring structure formed by R1 and the N atom is 1 to 3; R2 is a F atom or a trifluoromethyl group.

[0008] The battery cell of the present application uses an electrolyte comprising a specially designed fluorosulfonamide solvent, which can extend the cycle life of the battery cell and reduce the gas production of the battery cell.

[0009] In some embodiments, R1 is an oxaalkylene group having 3 to 4 carbon atoms.

[0010] In some embodiments, R1 is linked to the N atom to form a 5- to 6-membered ring.

[0011] R1 is connected to the N atom to form a 5- to 6-membered ring, which can not only improve the reduction resistance, reduce the consumption of active lithium, and increase the cycle life of the battery cell, but also reduce the risk of gas production in the battery cell and improve the solubility of the electrolyte salt.

[0012] In some embodiments, the number of O atoms in the cyclic structure formed by connecting R1 and the N atom is 1.

[0013] In some embodiments, R2 is a F atom, which can lead to better solubility of the electrolyte salt.

[0014] In some embodiments, the fluorosulfonamide solvent includes one or more of the following:

[0015]

[0016] In some embodiments, the fluorosulfonamide solvent includes one or more of A-2, A-3, and A-4, thereby achieving excellent electrolyte salt solubility, outstanding redox stability, and low gas generation performance.

[0017] In some embodiments, the electrolyte salt includes one or more of a fluorosulfonamide lithium salt represented by formula II, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium dioxalatoborate, lithium difluorooxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0018]

[0019] R3 is a 3- to 8-membered oxygen heterocarbon ring which is substituted or unsubstituted by a substituent R, the number of O atoms on the oxygen heterocarbon ring is 1 to 3, and the substituent R includes one or more of methyl, ethyl, propyl, and isopropyl.

[0020] In some embodiments, the electrolyte salt includes a fluorosulfonamide lithium salt represented by Formula II.

[0021] The combination of the fluorosulfonamide lithium salt of Formula II and the fluorosulfonamide solvent of Formula I prevents significant reduction of the electrolyte components on the negative electrode side, thereby further improving the cycle life of the battery cells. Furthermore, the fluorosulfonamide lithium salt of Formula II and the fluorosulfonamide solvent of Formula I have a specific structure that, even with some degree of reduction, does not significantly alter the electrolyte component ratios, thereby significantly reducing the risk of gassing in the battery cells.

[0022] In some embodiments, R3 is a 5- to 6-membered carbonyl ring which is substituted or unsubstituted with the substituent R.

[0023] In some embodiments, R3 is an unsubstituted 5- to 6-membered oxacarbocycle.

[0024] R3 is a 5- to 6-membered oxygen-carbon ring, which can improve the reduction resistance of anions, reduce the consumption of active lithium, increase the cycle life of battery cells, reduce the risk of gas production in battery cells, and enable fluorosulfonamide lithium salts to have good ion transport properties.

[0025] In some embodiments, the number of O atoms in the oxocarbocycle is 1.

[0026] In some embodiments, the substituent R is a methyl group, which is beneficial for improving the solubility of the fluorosulfonamide lithium salt represented by Formula II in the solvent.

[0027] In some embodiments, the fluorosulfonamide lithium salt represented by Formula II includes one or more of the following:

[0028]

[0029] In some embodiments, the fluorosulfonamide lithium salt represented by Formula II includes one or more of B-6 and B-10, thereby achieving good reduction resistance, high negative electrode affinity, and low gas generation performance.

[0030] In some embodiments, the concentration of the electrolyte salt in the electrolyte solution is 0.5 mol / L-4 mol / L, and can be optionally 1.5 mol / L-2.5 mol / L. The concentration of the electrolyte salt within the above range helps the battery cell have a longer cycle life.

[0031] In some embodiments, the mass percentage of the fluorosulfonamide solvent in the solvent is 100%.

[0032] In some embodiments, the mass proportion of the fluorosulfonamide solvent in the solvent is greater than or equal to 60% and less than 100%, and can be optionally 80%-95%.

[0033] In some embodiments, the solvent further comprises a cyclic ether solvent, and the cyclic ether solvent comprises one or more of tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 2,2-bis(trifluoromethyl)-1,3-dioxolane, and 2-(trifluoromethyl)-1,3-dioxolane.

[0034] In some embodiments, the mass proportion of the cyclic ether solvent in the solvent is greater than 0 and less than or equal to 40%, and can be optionally 5%-20%.

[0035] Adding an appropriate amount of cyclic ether solvent to the electrolyte can assist in dissolving the electrolyte salt.

[0036] In some embodiments, the battery cell comprises a lithium metal battery cell or a negative electrode-free lithium metal battery cell.

[0037] In some embodiments, the upper limit voltage of charging and discharging of the battery cell is greater than or equal to 4V.

[0038] In a second aspect, the present application provides a battery comprising the battery cell of the first aspect of the present application.

[0039] In a third aspect, the present application provides an electrical device comprising the battery according to the second aspect of the present application.

[0040] The electric device of the present application includes the battery provided by the present application, and thus has at least the same advantages as the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] To more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive effort.

[0042] Figure 1 It is a schematic diagram of an embodiment of a battery cell of the present application.

[0043] Figure 2 It is an exploded schematic diagram of an embodiment of a battery cell of the present application.

[0044] Figure 3 It is a schematic diagram of an embodiment of a battery module of the present application.

[0045] Figure 4 It is a schematic diagram of an embodiment of the battery pack of the present application.

[0046] Figure 5 yes Figure 4 An exploded schematic diagram of an embodiment of a battery pack is shown.

[0047] Figure 6 It is a schematic diagram of an embodiment of an electric device including the battery of the present application as a power source.

[0048] In the accompanying drawings, which are not necessarily drawn to scale, reference numerals are as follows: 1 battery pack, 2 upper housing, 3 lower housing, 4 battery module, 5 battery cell, 51 housing, 52 electrode assembly, 53 cover plate. DETAILED DESCRIPTION

[0049] Below, the embodiments of the battery cell, battery, and electrical device of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0050] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0051] Unless otherwise specified, 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.

[0052] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of this application.

[0053] Unless otherwise specified, all steps of the present 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 may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0054] Unless otherwise specified, in this application, the terms "first", "second", "third", etc. are used to distinguish different objects rather than to describe a specific order or a primary-secondary relationship.

[0055] Unless otherwise specified, the terms used in this application have the common meanings that are commonly understood by those skilled in the art.

[0056] Unless otherwise stated, the numerical values ​​of the various parameters mentioned in this application can be measured using various test methods commonly used in the art, for example, they can be measured according to the test methods given in the examples of this application. Unless otherwise stated, the test temperature of each parameter is 25°C.

[0057] The battery mentioned in the embodiments of the present application may include 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 may include a battery cell, a battery module or a battery pack.

[0058] A battery cell is the smallest unit that makes up a battery and can independently realize the function of charging and discharging. A battery cell can be cylindrical, rectangular or other shapes, etc., which is not limited in the embodiments of the present application. Figure 1 As an example, a battery cell 5 having a rectangular parallelepiped structure is shown.

[0059] When there are multiple battery cells, the multiple battery cells are connected in series, in parallel, or in mixed series via a busbar. In some embodiments, the battery may 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 embodiments, the battery may be a battery pack, which includes a housing and battery cells, with the battery cells or battery modules housed in the housing. In some embodiments, the housing may serve as part of the vehicle's chassis structure. For example, a portion of the housing may form at least a portion of the vehicle's floor, or a portion of the housing may form at least a portion of the vehicle's crossbeam or longitudinal beam.

[0060] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0061] The battery cell includes an electrode assembly, which may be a wound structure or a laminated structure, and the present invention is not limited thereto.

[0062] The battery cell may also include an outer packaging, which can be used to encapsulate the electrode assembly and electrolyte. The outer packaging can be a hard shell, such as a hard plastic shell, aluminum shell, steel shell, etc. The outer packaging can also be a soft package, such as a bag-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 Figure 2 As shown, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate. The base plate and side plates together form a receiving cavity. The housing 51 has an opening communicating with the receiving cavity. The cover plate 53 is used to cover the opening, thereby sealing the receiving cavity. The electrode assembly 52 is enclosed in the receiving cavity. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and can be adjusted according to needs.

[0064] In some embodiments, battery cells may be assembled into a battery module. A battery module may contain multiple battery cells, and the specific number may be adjusted according to the application and capacity of the battery module. Figure 3 FIG. 4 is a schematic diagram of a battery module 4 as an example. Figure 3 As shown, in the battery module 4, the plurality of battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, they can also be arranged in any other manner. Further, the plurality of battery cells 5 can be fixed by fasteners.

[0065] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0066] In some embodiments, the battery modules described above may also be assembled into a battery pack, and the number of battery modules contained in the battery pack may be adjusted according to the application and capacity of the battery pack.

[0067] Figure 4 and Figure 5 FIG. 1 is a schematic diagram of a battery pack 1 as an example. Figure 4 and Figure 5 As shown, a battery pack 1 may include a housing and multiple battery modules 4 disposed therein. The housing comprises an upper housing 2 and a lower housing 3. The upper housing 2 covers the lower housing 3 and forms an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 may be arranged in any manner within the housing.

[0068] An embodiment of the present application provides a battery cell that uses an electrolyte comprising a specially designed fluorosulfonamide solvent. The electrolyte can extend the cycle life of the battery cell and reduce the gas production of the battery cell.

[0069] The battery cells provided in the embodiments of the present application may include lithium metal battery cells and negative electrode-free lithium metal battery cells.

[0070] The battery cell provided in the embodiments of the present application includes an electrolyte, and the electrolyte includes an electrolyte salt and a solvent.

[0071] The solvent includes a fluorosulfonamide solvent shown in formula I, wherein R1 is an oxoalkylene group having 2 to 7 carbon atoms, R1 is connected to the N atom to form a 4- to 8-membered ring, and the number of O atoms on the ring structure formed by connecting R1 and the N atom is 1 to 3; R2 is a F atom or a trifluoromethyl group.

[0072]

[0073] In Formula I, oxaalkylene refers to a group formed by replacing the C atoms on the alkylene main chain with 1 to 3 O atoms. The alkylene may or may not have a branched structure. The number of C atoms in the alkylene is 2 to 7, and the total number of O atoms and C atoms in the ring of the cyclic structure formed by connecting R1 and the N atom is 4 to 8.

[0074] The electrolyte solvent includes a fluorosulfonamide solvent represented by Formula I, which can significantly improve the stability of the positive electrode. This is because the fluorosulfonamide solvent represented by Formula I has a sulfur-oxygen double bond in its structure, which can make the sulfur atom center highly electron-deficient, thereby forming a conjugate with the lone pair of electrons of the nitrogen atom. Therefore, the structure of the fluorosulfonamide solvent is highly stable.

[0075] The fluorosulfonamide solvents shown in Formula I utilize a F atom or a trifluoromethyl group directly attached to a sulfur atom, thereby providing good solubility for the electrolyte salt. As the chain length of R2 increases, the solubility of the fluorosulfonamide solvent for the electrolyte salt decreases significantly, or even becomes almost insoluble.

[0076] In the fluorosulfonamide solvent structure shown in Formula I, R1 is an oxoalkylene group having 2 to 7 carbon atoms. The R1 group has a strong power supply effect and, when connected to the N atom, can also improve the reduction resistance of the fluorosulfonamide solvent.

[0077] In the fluorosulfonamide solvent structure shown in Formula I, R1 is an oxaalkylene group with 2 to 7 carbon atoms. This improves affinity with the anode, ensuring good electrolyte wettability of the battery cells even after extended cycling. R1 forms a ring with the nitrogen atom, significantly reducing the risk of gassing in the battery cells.

[0078] Therefore, the battery cell provided in the embodiment of the present application can have a long cycle life and low gas production. The gas production of the battery cell is reduced, and the reliability of the battery cell is also improved.

[0079] Alternatively, R1 may be an oxaalkylene group having 3 to 4 carbon atoms.

[0080] Optionally, R1 is linked to the N atom to form a 5- to 6-membered ring.

[0081] R1 connects with the N atom to form a 5- to 6-membered ring. This structure is stable and has a low risk of ring opening. At the same time, its structure is of moderate size, allowing for better dissolution of electrolyte salts. Therefore, R1 connecting with the N atom to form a 5- to 6-membered ring can improve reduction resistance, reduce active lithium consumption, and increase the cycle life of the battery cell. It can also reduce the risk of gassing in the battery cell and improve the solubility of the electrolyte salt.

[0082] When the number of O atoms in the ring structure formed by connecting R1 and the N atom is 2 or 3, the distance between two adjacent O atoms should not be too close. If the distance between two adjacent O atoms is too close, an acetal structure that is easily hydrolyzed and oxidized is easily formed.

[0083] Optionally, the number of O atoms in the ring of the cyclic structure formed by connecting R1 and the N atom is 1.

[0084] Alternatively, R2 may be a F atom, which may result in better solubility of the electrolyte salt.

[0085] Optionally, the fluorosulfonamide solvent may include one or more of the following:

[0086]

[0087] Optionally, the fluorosulfonamide solvent may include one or more of A-2, A-3, A-4, A-5, A-6, A-8, A-9, and A-10. This can improve reduction resistance, reduce active lithium consumption, and increase the cycle life of the battery cells, while also reducing the risk of gassing in the battery cells and improving the solubility of the electrolyte salt.

[0088] Optionally, the fluorosulfonamide solvent may include one or more of A-2, A-3, A-4, and A-5, thereby achieving better electrolyte salt solubility.

[0089] Optionally, the fluorosulfonamide solvent may include one or more of A-2, A-3, and A-4, thereby achieving excellent electrolyte salt solubility, outstanding redox stability, and low gas generation performance.

[0090] In some embodiments, the electrolyte salt may include one or more of a fluorosulfonamide lithium salt represented by Formula II, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium dioxalatoborate, lithium difluorooxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0091]

[0092] R3 is a 3- to 8-membered oxygen heterocarbon ring which is substituted or unsubstituted by a substituent R, the number of O atoms on the oxygen heterocarbon ring is 1 to 3, and the substituent R includes one or more of methyl, ethyl, propyl, and isopropyl.

[0093] In formula II, a 3- to 8-membered oxygen heterocarbocycle refers to a cyclic structure formed by connecting one or more O atoms to one or more C atoms, wherein the total number of O atoms and C atoms in the cyclic structure is 3 to 8, and the number of O atoms in the cyclic structure is 1 to 3. Each C atom in the oxygen heterocarbocycle may be independently substituted with a substituent R, i.e., the C atom may be in the form of -CHR- or -C(R)2-, or may not be substituted with a substituent R, i.e., the C atom may be in the form of -CH2-.

[0094] Alternatively, the electrolyte salt may include a fluorosulfonamide-based lithium salt represented by Formula II.

[0095] The anion of the fluorosulfonamide lithium salt shown in Formula II has a sulfonyl fluoride structure at one end and an oxygen-heterocarbocyclic ring at the other. The oxygen-heterocarbocyclic ring has a strong power-generating effect, stabilizing the anion and improving its reduction resistance. This, in turn, reduces active lithium consumption and increases the cycle life of the battery cell.

[0096] The anion of the fluorosulfonamide lithium salt shown in Formula II has an oxygen-heterocarbon ring as the terminal group. Compared with the cyclic alkyl structure and the chain alkyl structure, the oxygen-heterocarbon ring also has a certain affinity for the negative electrode, thereby avoiding the deterioration of the electrolyte wettability and ion transport performance of the negative electrode due to the significant difference in the affinity of the two ends of the anion to the negative electrode.

[0097] The anions of the fluorosulfonamide lithium salts shown in Formula II, which have oxygen-heterocarbocyclic end groups, can also reduce the problem of excessive gas production in battery cells caused by end groups with chain alkoxy structures. This is because chain alkoxy structures react with lithium to produce gas, which increases the risk of gas production in battery cells. For example, chain alkoxy structures with methoxy end groups react with lithium to produce methane (CH4) gas, as shown in the following reaction equation.

[0098] R0-O--CH3+Li→Li--CH3+R0-O--Li

[0099]

[0100] The anion of the fluorosulfonamide lithium salt shown in Formula II has an oxygen heterocarbon ring as the terminal group. Even if a similar reduction process as mentioned above occurs, gas substances will not be directly generated, thereby effectively reducing the risk of gas production in battery cells.

[0101] Therefore, using the fluorosulfonamide lithium salt of Formula II in combination with the fluorosulfonamide solvent of Formula I can prevent significant reduction of the electrolyte components on the negative electrode side, thereby further improving the cycle life of the battery cells. Furthermore, the fluorosulfonamide lithium salt of Formula II and the fluorosulfonamide solvent of Formula I have a specific structure that, even if reduced to a certain extent, does not significantly change the proportions of the electrolyte components, thereby significantly reducing the risk of gassing in the battery cells.

[0102] Optionally, the substituent R may be a methyl group, which is beneficial for improving the solubility of the fluorosulfonamide lithium salt represented by Formula II in the solvent.

[0103] Alternatively, R3 may be an unsubstituted 3- to 8-membered oxygen heterocarbon ring, that is, R3 may be formed by 1 to 3 O atoms and one or more methylene groups -CH2-.

[0104] Alternatively, R3 may be a 5- to 6-membered oxacarbocyclic ring which may be substituted or unsubstituted by the substituent R. More preferably, R3 may be an unsubstituted 5- to 6-membered oxacarbocyclic ring.

[0105] R3 is a 5- to 6-membered oxygen-heterocarbocyclic ring. This ring has a stable structure and a low risk of ring opening. Furthermore, its structure is of moderate size and exhibits excellent ion transport properties. Therefore, a 5- to 6-membered oxygen-heterocarbocyclic ring can improve the reduction resistance of anions, reduce active lithium consumption, increase the cycle life of battery cells, reduce the risk of gassing in battery cells, and enhance the ion transport properties of fluorosulfonamide lithium salts.

[0106] When the number of O atoms on the oxygen heterocycle is 2 or 3, the distance between two adjacent O atoms should not be too close. If the distance between two adjacent O atoms is too close, an acetal structure that is easily hydrolyzed and oxidized is easily formed.

[0107] Alternatively, the number of O atoms on the ring of the oxygen heterocarbocycle may be 2. More preferably, the number of O atoms on the ring of the oxygen heterocarbocycle may be 1.

[0108] In some embodiments, the fluorosulfonamide lithium salt of Formula II may include one or more of the following:

[0109]

[0110] Optionally, the fluorosulfonamide lithium salt represented by Formula II may include one or more of B-5 to B-14. This can improve the reduction resistance of the anion, reduce the consumption of active lithium, and increase the cycle life of the battery cell, while also reducing the risk of gassing in the battery cell. Furthermore, the fluorosulfonamide lithium salt can have good ion transport properties.

[0111] Optionally, the fluorosulfonamide lithium salt represented by Formula II may include one or more of B-5, B-6, B-8, B-9, and B-10.

[0112] Alternatively, the fluorosulfonamide lithium salt represented by Formula II may include one or more of B-6 and B-10, thereby achieving good reduction resistance, high negative electrode affinity, and low gas generation performance.

[0113] The present application embodiment illustratively provides the preparation method of compound A-4, compound B-6. Other compounds of the present application embodiment can be prepared with reference to this exemplary method. According to the preparation method of the exemplary compound, those skilled in the art can easily obtain the specific method for realizing each synthesis step from the relevant scientific literature or the standard textbook in this field. Unless otherwise specified, commercially available or known compounds in the literature are used as the raw materials for synthesis. Those skilled in the art of organic synthesis will recognize that, for the purpose of optimizing the generation of the compounds described herein, the nature and order of the proposed synthesis steps can be changed.

[0114] The processes described in the examples of the present application can be monitored by any suitable method known in the art. For example, product formation can be monitored by spectroscopic means such as nuclear magnetic resonance spectroscopy (NMR, e.g. 1 H. 13 C or 19 F), infrared spectroscopy (IR), spectrophotometry (e.g., UV-visible), mass spectrometry (MS), or by chromatography, such as high performance liquid chromatography (HPLC), gas chromatography (GC), gel permeation chromatography (GPC), or thin layer chromatography (TLC).

[0115] Illustratively, compound A-4 can be prepared as follows.

[0116]

[0117] Sulfonyl chloride (20.0 g, 0.148 mol) and triethylamine (15.0 g, 0.148 mol) were added to a 500 mL two-necked flask under argon protection. Then, 200 mL of anhydrous tetrahydrofuran was added to dissolve the mixture and stirred at room temperature (25°C in this application). Morpholine (12.91 g, 0.148 mol) was added dropwise. After the addition was complete, the mixture was stirred at 40-45°C for 1 hour, then cooled to room temperature. 60 mL of potassium bifluoride (28.9 g, 0.37 mol) solution was added and stirred at room temperature for 2 hours. After the reaction was complete, the mixture was extracted with methyl tert-butyl ether (50 mL × 3). The organic phase was washed with saturated brine, separated, and then dried over anhydrous sodium sulfate. Filtered, the filtrate was concentrated under reduced pressure to remove the organic solvent to obtain a crude product, which was finally distilled under reduced pressure to obtain 12.02 g of a colorless liquid, namely compound A-4. Molar yield: 48.01%.

[0118] 1 H NMR (CDCl3, 400MHz), δ (ppm): 3.67 (m, 4H), 2.9 (s, 4H). 13 C NMR (CDCl3, 100MHz), δ (ppm): 70.1, 43.8. 19 F NMR(CDCl3,376MHz),δ(ppm):-129.4.HRMS(ESI+)m / z[M] + calcd.for C4H8FNO3S:169.0209.found:169.0214.

[0119] Illustratively, compound B-6 can be prepared as follows.

[0120]

[0121] Sulfonyl chloride (20.0 g, 0.148 mol) and triethylamine (15.0 g, 0.148 mol) were added to a 500 mL two-necked flask under argon protection. 200 mL of anhydrous tetrahydrofuran (THF) was then added to dissolve the mixture and stirred at room temperature. 3-Aminotetrahydrofuran (12.89 g, 0.148 mol) was added dropwise and stirred at room temperature for 1 hour. Then, 60 mL of potassium bifluoride (28.9 g, 0.37 mol) solution was added and stirred at room temperature for 2 hours. After the reaction was complete, extraction was performed with methyl tert-butyl ether (50 mL x 3). The organic phase was washed with saturated brine, separated, and then dried over anhydrous sodium sulfate. The organic phase was filtered and the filtrate was concentrated under reduced pressure to remove the organic solvent to obtain a crude product, 14.64 g of a colorless liquid compound intermediate.

[0122] 1H NMR (DMSO-d6, 400MHz), δ (ppm): 3.97 (m, 2H), 3.75 (m, 2H), 2.98 (m, 1H), 2.07 (m, 2H), 2.0 (s, 1H). 13 C NMR (DMSO-d6, 100MHz), δ (ppm): 73.3, 63.3, 43.0, 31.4. 19 F NMR(DMSO-d6,376MHz),δ(ppm):-129.7.HRMS(ESI+)m / z[M] + calcd.for C4H8FNO3S:169.0209.found:169.0214.

[0123] The intermediate compound (2.0 g, 11.82 mmol) was weighed and added to a 25 mL single-necked bottle, dissolved in 10 mL of methanol, cooled to below 10°C, and then added dropwise with an aqueous lithium hydroxide solution (LiOH, 0.283 g, 11.82 mmol dissolved in 1 mL of water). After the addition was completed, the temperature was raised to room temperature and stirred for 15 h until there was no NH chemical shift and the reaction was complete. The reaction was concentrated under reduced pressure to remove methanol, filtered, dried, and finally recrystallized to obtain 1.05 g of compound B-6 with a yield of 50.72%.

[0124] 1 H NMR (DMSO-d6, 400MHz), δ (ppm): 3.80 (m, 2H), 3.75 (m, 2H), 1.90 (m, 3H). 13 C NMR (DMSO-d6, 100MHz), δ (ppm): 68.0, 62.0, 20.0, 17.0. 19 F NMR(DMSO-d6,376MHz),δ(ppm):-129.7.HRMS(ESI+)m / z[M] + calcd.for C4H7FLiNO3S:175.0291.found:175.0288.

[0125] In some embodiments, the concentration of the electrolyte salt in the electrolyte solution may be 0.5 mol / L-4 mol / L, for example, 0.5 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 thereof. Alternatively, the concentration of the electrolyte salt in the electrolyte solution may be 1 mol / L-3 mol / L, or 1.5 mol / L-2.5 mol / L.

[0126] The concentration of the electrolyte salt within the above range helps the battery cell have a longer cycle life.

[0127] In some embodiments, the mass percentage of the fluorosulfonamide solvent in the solvent may be 100%.

[0128] In some embodiments, the weight percentage of the fluorosulfonamide solvent in the solvent may be greater than or equal to 60% and less than 100%, for example, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, or any range thereof. Alternatively, the weight percentage of the fluorosulfonamide solvent in the solvent may be 80%-95%.

[0129] In some embodiments, the solvent may further include a cyclic ether solvent. The cyclic ether solvent may have a branched structure or may not have a branched structure.

[0130] The solubility of electrolyte salts in some fluorosulfonamide solvents with larger structural designs is slightly poor. Adding an appropriate amount of cyclic ether solvent to the electrolyte can help dissolve the electrolyte salt.

[0131] Compared with conventional chain ether solvents, the use of cyclic ether solvents can also reduce the reduction gas production on the negative electrode side.

[0132] Alternatively, the cyclic ether solvent may include one or more of tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 2,2-bis(trifluoromethyl)-1,3-dioxolane, and 2-(trifluoromethyl)-1,3-dioxolane.

[0133] More optionally, the cyclic ether solvent may include tetrahydropyran, which can assist in dissolving the electrolyte salt while having good redox resistance, thereby facilitating both long cycle life and low gas generation performance of the battery cell.

[0134] Optionally, the mass proportion of the cyclic ether solvent in the solvent may be greater than 0 and less than or equal to 40%, for example, 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or any range thereof. Optionally, the mass proportion of the cyclic ether solvent in the solvent may be 5%-20%.

[0135] The cyclic ether solvent itself has low oxidation resistance, so its usage should not be too high.

[0136] Methods for preparing an electrolyte are well known. For example, an electrolyte salt and a solvent can be uniformly mixed to obtain an electrolyte. During the preparation process, the order in which the materials are added is not particularly limited; the materials can be added simultaneously or in batches.

[0137] The components and their contents in the electrolyte can be determined using conventional methods in the art. For example, the electrolyte in the battery cell can be extracted, and the various solvents and electrolyte salts in the electrolyte can be separated using gas chromatography. Each component can then be subjected to high-precision mass spectrometry and nuclear magnetic resonance spectroscopy to confirm its specific structure. After confirming the specific structure of each component, electrolyte salt solutions with different standard concentrations are prepared. The relationship between electrolyte salt content and peak area is fitted using the results of ion chromatography. By testing the electrolyte sample using ion chromatography, a quantitative result for the lithium salt concentration can be obtained. A mixture of solvent components with known ratios is prepared, and a solvent with known concentration is added as an internal standard. The relative correction factors for the peak area and concentration relationship of the internal standard for each component are obtained using the gas chromatography results. Gas chromatography is then performed on the electrolyte sample with the known internal standard added to obtain a quantitative result for the specific ratio of each solvent component.

[0138] The battery cell includes an electrolyte and an electrode assembly, and the electrode assembly includes a positive electrode sheet and a negative electrode sheet.

[0139] In some embodiments, the upper limit voltage of the battery cell charge and discharge may be greater than or equal to 4 V, and may optionally be greater than or equal to 4.2 V. The electrolyte provided in the embodiments of the present application can enable the battery cell to have high reduction resistance in a high voltage range, thereby enabling the battery cell to have a long cycle life, low gas production, and high reliability.

[0140] [Positive electrode]

[0141] In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material. For example, the positive electrode current collector has two opposing surfaces in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposing surfaces of the positive electrode current collector.

[0142] The positive electrode active material includes a material capable of extracting and inserting lithium. 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 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 their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, a composite material of lithium iron manganese phosphate and carbon, and their respective modified compounds.

[0143] The modified compounds of the above-mentioned positive electrode active materials may be used to perform doping modification and / or surface coating modification on the positive electrode active materials.

[0144] In some embodiments, in order to further improve the energy density of the battery cell, the positive electrode active material may include a general formula of Li a Ni b Co c M d O e A f One or more lithium transition metal oxides and modified compounds thereof. 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.

[0145] In some embodiments, as examples, the positive electrode active material may include but is not limited to LiCoO2, LiNiO2, LiMnO2, LiMn2O4, 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 Co0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 One or more of O2, LiFePO4, LiMnPO4, and their respective modified compounds.

[0146] In some embodiments, the positive electrode film layer may further 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.

[0147] In some embodiments, the positive electrode film layer may further 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), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic resin.

[0148] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. As an example of a metal foil, aluminum foil may be used. The composite current collector may 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 may include, but is not limited to, one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include, but is not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0149] The positive electrode film layer can be formed by coating a positive electrode slurry onto a positive electrode current collector, drying it, and cold pressing it. The positive electrode slurry is typically formed by dispersing the positive electrode active material, an optional positive electrode conductive agent, an optional positive electrode binder, and any other components in a solvent and stirring them uniformly. The solvent can be, but is not limited to, N-methylpyrrolidone (NMP).

[0150] [Negative electrode]

[0151] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a lithium-containing layer disposed on at least one surface of the negative electrode current collector.

[0152] In some embodiments, the material in the lithium-containing layer may include one or more of lithium element and lithium alloy.

[0153] A lithium alloy may be an alloy of metallic lithium and other metallic elements or non-metallic elements. For example, the other metallic elements in the lithium alloy may include one or more of tin, zinc, aluminum, magnesium, silver, gold, gallium, indium, and platinum, and the non-metallic elements in the lithium alloy may include one or more of boron, carbon, and silicon.

[0154] In some embodiments, the negative electrode sheet may include a negative electrode current collector but not a lithium-containing layer, thereby assembling to form a negative electrode-free lithium metal battery cell.

[0155] A negative electrode-free lithium metal battery cell generally refers to a battery cell in which a negative electrode active material layer is not actively provided on the negative electrode side during the manufacturing process of the battery cell. For example, a negative electrode active material layer is not formed by coating or deposition of a carbonaceous active material layer at the negative electrode during the manufacturing process of the battery cell. 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 metal phase. During discharge, the metal can be converted into metal ions and return to the positive electrode, realizing cyclic charge and discharge. Compared with other battery cells, negative electrode-free lithium metal battery cells can achieve higher energy density because they do not have a negative electrode active material layer.

[0156] In some embodiments, to improve battery cell performance, the negative electrode side of the negative electrode-free lithium metal battery cell may also be provided with some conventional substances that can be used as negative electrode active materials, such as carbon materials. Although these substances have a certain capacity, due to their low content and their non-use as the primary negative electrode active material in the battery cell, the battery cell thus constructed can still be considered a negative electrode-free lithium metal battery cell.

[0157] The CB value of a negative electrode-free lithium metal battery cell is typically very small. For example, in some embodiments, the CB value of a negative electrode-free lithium metal battery cell can be less than or equal to 0.1. The CB value is the unit area capacity of the negative electrode in the battery cell divided by the unit area capacity of the positive electrode. Because a negative electrode-free lithium metal battery cell contains no or only a small amount of negative electrode active material, the unit area capacity of the negative electrode is small, and thus the CB value is very small, for example, typically less than or equal to 0.1.

[0158] In some embodiments, the negative electrode current collector may include a metal foil, a three-dimensional porous current collector, or a composite current collector. As examples of metal foils, copper foil, copper alloy foil, nickel foil, nickel alloy foil, aluminum foil, and aluminum alloy foil may be used. As examples of three-dimensional porous current collectors, copper mesh, nickel mesh, aluminum mesh, foam copper, foam nickel, and foam aluminum may be used. The composite current collector may 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 may include, but is not limited to, one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include, but is not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0159] [Isolation film]

[0160] The battery assembly may also include a separator. This separator can be positioned between the positive and negative electrode sheets, primarily to prevent internal short circuits. This application does not specifically limit the type of separator; any known porous membrane with good chemical and mechanical stability may be used.

[0161] In some embodiments, the material of the isolation membrane may include, but is not limited to, one or more of fiberglass, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and polyimide. The isolation membrane may be a single-layer film or a multi-layer composite film. When the isolation membrane is a multi-layer composite film, the materials of each layer may be the same or different.

[0162] The preparation method of battery cells is well known. In some embodiments, the positive electrode sheet, separator, negative electrode sheet and electrolyte can be assembled to form a battery cell. As an example, the positive electrode sheet, separator, and negative electrode sheet can be formed into an electrode assembly through a winding process and / or a lamination process. The electrode assembly is placed in an outer package, dried, and then injected with electrolyte. After vacuum packaging and standing, a battery cell is obtained. Multiple battery cells can be further connected in series, in parallel, or in a mixed connection to form a battery module. Multiple battery modules can also be connected in series, in parallel, or in a mixed connection to form a battery pack. In some embodiments, multiple battery cells can also directly form a battery pack.

[0163] Electrical devices

[0164] The present application also provides an electrical device, which includes a battery provided in the present application. The battery can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device can be, but is not limited to, a mobile device (such as a mobile phone, a tablet computer, a laptop 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, a satellite, an energy storage system, etc.

[0165] The electric device can select the type of battery according to its usage requirements, such as a battery cell, a battery module or a battery pack.

[0166] Figure 6 The diagram is a schematic diagram of an exemplary electric device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of this device, a battery pack or battery module can be used.

[0167] As another example, an electric device may be a mobile phone, a tablet computer, a laptop computer, etc. Such an electric device is usually required to be lightweight and thin, and may use a battery cell as a power source.

[0168] Example

[0169] The following examples describe the present disclosure in more detail and are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further processing, and all instruments used in the examples are commercially available.

[0170] Example 1

[0171] (1) Preparation of electrolyte

[0172] Mix the fluorosulfonamide solvent A-4 and the cyclic ether solvent tetrahydropyran in a mass ratio of 9:1 to form a solvent mother liquor. Add 1.75 g of the fluorosulfonamide lithium salt B-6 to 5 ml of the solvent mother liquor and stir thoroughly to form a colorless, transparent electrolyte.

[0173] (2) Preparation of positive electrode sheet

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

[0175] (3) Preparation of negative electrode sheet

[0176] A 50 μm thick lithium foil was laminated to a 12 μm thick copper foil by roller pressing, and then cut into a 41 mm × 51 mm rectangle as a negative electrode sheet for later use.

[0177] (4) Preparation of isolation membrane

[0178] The polyethylene porous film was cut into a rectangle of 45 mm × 55 mm and used as a separator for later use.

[0179] (5) Preparation of battery cells

[0180] A cut positive electrode sheet and two cut negative electrode sheets were stacked together, separated by a separator to form an electrode assembly. The electrode assembly was placed in an aluminum-plastic film bag, and 0.30g of the prepared electrolyte was injected. After vacuum hot pressing and resting for at least 6 hours, a lithium metal battery cell was obtained. The rated capacity of the battery cell was 70mAh.

[0181] Cycle life test

[0182] At 25°C, the battery cell prepared above was charged at a constant current of 0.2C (14mA) to 4.3V. It was then charged at a constant voltage to a current of 0.1C (7mA). At this point, the battery cell was fully charged, and the charge capacity at this point was recorded as the first cycle charge capacity. After the battery cell was allowed to rest for 5 minutes, it was discharged at a constant current of 1C (70mA) to 2.8V. This constituted a cycle charge and discharge process, and the discharge capacity at this point was recorded as the first cycle discharge capacity. The battery cell was subjected to a cyclic charge and discharge test according to the above method, and the discharge capacity after each cycle was recorded. The battery cell was considered to have reached the end of its life when its discharge capacity decayed to 80% of its first cycle discharge capacity. The number of cycles at this point was used to characterize the cycle life of the battery cell.

[0183] Gas production test

[0184] Use the Archimedean displacement method to test gas production. First, take a beaker and add a certain amount of dimethyl silicone oil to it. Immerse the battery cell before cycling in the dimethyl silicone oil. Place the beaker, dimethyl silicone oil, and battery cell on a balance and record the total mass m1. After the battery cell has cycled 300 times according to the above method, immerse the battery cell again in dimethyl silicone oil and place the beaker, dimethyl silicone oil, and battery cell on a balance and record the total mass m2 again. The gas production of the battery cell after 300 cycles is L = (m2-m1) / ρ. ρ is the density of dimethyl silicone oil, measured in g / ml. m1 is the total mass of the beaker, dimethyl silicone oil, and battery cell before cycling, measured in g. m2 is the total mass of the beaker, dimethyl silicone oil, and battery cell after 300 cycles, measured in g.

[0185] Example 2

[0186] The preparation and testing methods of the battery cells are similar to those in Example 1, except that the composition of the electrolyte is different.

[0187] Take 1.87g of lithium bis(fluorosulfonyl)imide (LiFSI) and add 5ml of a solvent mother liquor prepared by mixing fluorosulfonamide solvent A-4 and cyclic ether solvent tetrahydropyran in a mass ratio of 9:1. Stir thoroughly to form a colorless and transparent electrolyte.

[0188] Comparative Example 1

[0189] The preparation and testing methods of the battery cells are similar to those in Example 1, except that the composition of the electrolyte is different.

[0190] Take 0.76g of lithium hexafluorophosphate, add 5ml of a solvent mother solution of ethylene carbonate and ethyl methyl carbonate in a mass ratio of 3:7, stir thoroughly to form a colorless and transparent electrolyte.

[0191] Comparative Example 2

[0192] The preparation and testing methods of the battery cells are similar to those in Example 1, except that the composition of the electrolyte is different.

[0193] Take 1.75g ​​of fluorosulfonamide lithium salt B-6, add 5ml of solvent mother solution prepared by mixing N,N-dimethylaminosulfonyl fluoride and tetrahydropyran in a mass ratio of 9:1, and stir thoroughly to form a colorless and transparent electrolyte.

[0194] Table 1

[0195]

[0196] The test results of Example 1 and Comparative Example 1 indicate that the electrolyte comprising a fluorosulfonamide lithium salt and a fluorosulfonamide solvent of the present application can improve the cycle life of battery cells and reduce gas production. The electrolyte of Comparative Example 1 is suitable for lithium-ion battery cells and does not significantly improve the performance of lithium metal battery cells.

[0197] The test results of Example 1 and Comparative Example 2 show that when conventional dimethylamine sulfonyl fluoride solvent is used, the alkyl group connected to the N atom in its structure has poor affinity with the negative electrode, which leads to a poor cycle life of the battery monomer. At the same time, the use of alkyl groups as end groups is also prone to reduction reactions, resulting in a high gas production of the battery monomer.

[0198] From the test results of Example 1 and Example 2, it can be seen that using the fluorosulfonamide lithium salt represented by Formula II as the electrolyte salt can enable the battery cell to have a lower gas production and a longer cycle life.

[0199] Examples 3 to 5

[0200] The preparation method and testing method of the battery cell are similar to those in Example 1, except that the type of electrolyte salt in the electrolyte is different. See Table 2 for details.

[0201]

[0202]

[0203] Table 2

[0204]

[0205] It can be seen from the test results of Examples 1 and 3 to 5 that by further selecting the type of fluorosulfonamide lithium salt represented by Formula II, the battery cell can have a longer cycle life and lower gas production.

[0206] Examples 6 to 9

[0207] The preparation and testing methods of the battery cells are similar to those of Example 3, except that the type of fluorosulfonamide solvent in the electrolyte is different. See Table 3 for details.

[0208]

[0209]

[0210] Table 3

[0211]

[0212] It can be seen from the test results of Example 3 and Examples 6 to 9 that by further selecting the type of fluorosulfonamide solvent, the battery monomer can have a longer cycle life and lower gas production.

[0213] Examples 10 to 11

[0214] The preparation and testing methods of the battery cells are similar to those of Example 3, except that the type of cyclic ether solvent in the electrolyte is different. See Table 4 for details.

[0215] Table 4

[0216]

[0217] It can be seen from the test results of Example 3 and Examples 10 to 11 that by further selecting the type of cyclic ether solvent, the battery monomer can have a longer cycle life and lower gas production.

[0218] Examples 12 to 17

[0219] The preparation method and testing method of the battery cell are similar to those of Example 3, except that the molar concentration of the electrolyte salt in the electrolyte is different. See Table 5 for details.

[0220] Table 5

[0221]

[0222]

[0223] It can be seen from the test results of Example 3 and Examples 12 to 17 that by further adjusting the molar concentration of the electrolyte salt, the battery cell can have a longer cycle life and lower gas production.

[0224] Examples 18 to 21

[0225] The preparation and testing methods of the battery cells are similar to those of Example 3, except that the mass ratios of the fluorosulfonamide solvent and the cyclic ether solvent in the electrolyte are different. See Table 6 for details.

[0226] Table 6

[0227]

[0228] Examples 22 to 25

[0229] The preparation and testing methods of the battery cells are similar to those of Example 9, except that the mass ratios of the fluorosulfonamide solvent and the cyclic ether solvent in the electrolyte are different. See Table 7 for details.

[0230] Table 7

[0231]

[0232] The test results in Tables 6 and 7 show that adding a small amount of cyclic ether solvent to the solvent can extend the cycle life of the battery cells. Because cyclic ether solvents themselves have lower oxidation resistance than fluorosulfonamide solvents, using a higher amount of cyclic ether solvent will reduce the cycle life of the battery cells and increase gas production.

[0233] The test results in Tables 6 and 7 also show that cyclic ether solvents have a better auxiliary dissolution effect on fluorosulfonamide solvents with larger structural designs, and can also significantly improve the cycle life of battery cells.

[0234] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and within the scope of the technical solution of the present application, embodiments having substantially the same structure as the technical idea and exerting the same effects are all included in the technical scope of the present application. In addition, within the scope of the subject matter of the present application, various modifications that can be conceived by those skilled in the art to the embodiments, and other methods constructed by combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A battery cell comprising an electrolyte, wherein the electrolyte comprises an electrolyte salt and a solvent, wherein: The solvent includes a fluorosulfonamide solvent represented by formula I, R1 is an oxaalkylene group having 2 to 7 carbon atoms, R1 is connected to the N atom to form a 4- to 8-membered ring, and the number of O atoms on the ring structure formed by R1 and the N atom is 1 to 3; R2 is a F atom or a trifluoromethyl group.

2. The battery cell according to claim 1, wherein: The fluorosulfonamide solvent satisfies at least one of the following conditions (1) to (4): (1) R1 is an oxaalkylene group having 3 to 4 carbon atoms; (2) R1 is connected to the N atom to form a 5- to 6-membered ring; (3) The number of O atoms in the ring structure formed by connecting R1 and the N atom is 1; (4) R2 is a F atom.

3. The battery cell according to any one of claims 1 to 2, characterized in that: The fluorosulfonamide solvents include one or more of the following:

4. The battery cell according to claim 3, characterized in that The fluorosulfonamide solvent includes one or more of A-2, A-3, and A-4.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The electrolyte salt includes one or more of the following: fluorosulfonamide lithium salts shown in formula II, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium dioxalatoborate, lithium difluorooxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate. R3 is a 3- to 8-membered oxygen heterocarbon ring which is substituted or unsubstituted by a substituent R, the number of O atoms on the oxygen heterocarbon ring is 1 to 3, and the substituent R includes one or more of methyl, ethyl, propyl, and isopropyl.

6. The battery cell according to claim 5, characterized in that The electrolyte salt includes a fluorosulfonamide lithium salt represented by Formula II.

7. The battery cell according to any one of claims 5 to 6, characterized in that: The fluorosulfonamide lithium salt represented by formula II satisfies at least one of the following conditions (1) to (4): (1) R3 is a 5- to 6-membered oxygen heterocarbon ring substituted or unsubstituted by a substituent R; (2) R3 is an unsubstituted 5- to 6-membered oxygen heterocarbon ring; (3) The number of O atoms on the ring of the oxygen heterocycle is 1; (4) The substituent R is a methyl group.

8. The battery cell according to any one of claims 5 to 7, characterized in that: The fluorosulfonamide lithium salt represented by formula II includes one or more of the following:

9. The battery cell according to claim 8, characterized in that The fluorosulfonamide lithium salt represented by formula II includes one or more of B-6 and B-10.

10. The battery cell according to any one of claims 1 to 9, characterized in that: The concentration of the electrolyte salt in the electrolyte solution is 0.5 mol / L-4 mol / L.

11. The battery cell according to claim 10, characterized in that The concentration of the electrolyte salt in the electrolyte solution is 1.5 mol / L-2.5 mol / L.

12. The battery cell according to any one of claims 1 to 11, characterized in that: The mass proportion of the fluorosulfonamide solvent in the solvent is greater than or equal to 60% and less than 100%.

13. The battery cell according to claim 12, characterized in that: The mass proportion of the fluorosulfonamide solvent in the solvent is 80%-95%.

14. The battery cell according to any one of claims 1 to 11, characterized in that: The mass percentage of the fluorosulfonamide solvent in the solvent is 100%.

15. The battery cell according to any one of claims 1 to 13, characterized in that: The solvent also includes a cyclic ether solvent, The cyclic ether solvent includes one or more of tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 2,2-bis(trifluoromethyl)-1,3-dioxolane, and 2-(trifluoromethyl)-1,3-dioxolane; and / or The mass proportion of the cyclic ether solvent in the solvent is greater than 0 and less than or equal to 40%.

16. The battery cell according to claim 15, characterized in that The mass proportion of the cyclic ether solvent in the solvent is 5%-20%.

17. The battery cell according to any one of claims 1 to 16, characterized in that: The battery cell includes one of a lithium metal battery cell and a negative electrode-free lithium metal battery cell; and / or, The upper limit voltage of charging and discharging of the battery cell is greater than or equal to 4V.

18. A battery, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 17.

19. An electrical device, characterized in that: Including the battery according to claim 18.

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