Electrolytes, individual cells, energy storage devices and power systems

Abstract

This application provides an electrolyte, a single-cell battery, an energy storage device, and an electrical system. The electrolyte of this application includes a first organic solvent, a second organic solvent, an electrolyte salt, and a phase stabilizer. The first organic solvent and the second organic solvent interweave to form their respective continuous network structures. The phase stabilizer is located at the phase interface between the first organic solvent and the second organic solvent. The hydrophobic parameter of the first organic solvent is smaller than that of the second organic solvent. The electrolyte salt is dissolved in both the first organic solvent and the second organic solvent. When the electrolyte of this application is applied to a single-cell battery, it can enable the single-cell battery to have a higher cycle life.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to an electrolyte, a single cell, an energy storage device, and an electrical system. Background Technology

[0002] Currently, carbonates and carboxylic esters are the main solvents in commercial lithium-ion battery electrolytes due to their wide operating temperature window, superior polarity, stable supply, and low cost. However, in battery systems using graphite and silicon as anode materials, these solvents have a narrow electrochemical stability window. As the active material expands and contracts during charging and discharging, electrolyte decomposition reactions continue to occur at the newly exposed interfaces, consuming electrolyte and active lithium, thus reducing the battery's cycle life. Summary of the Invention

[0003] This application provides an electrolyte that, when applied to a single battery cell, can enable the single battery cell to have a high cycle life.

[0004] In a first aspect, embodiments of this application provide an electrolyte comprising a first organic solvent, a second organic solvent, an electrolyte salt, and a phase stabilizer. The first organic solvent and the second organic solvent interweave to form their respective continuous network structures, and the phase stabilizer is located at the phase interface between the first organic solvent and the second organic solvent. The hydrophobic parameter of the first organic solvent is smaller than that of the second organic solvent, and the electrolyte salt is dissolved in the first organic solvent and the second organic solvent.

[0005] Furthermore, if the hydrophobic parameter of the first organic solvent is LogP1 and the hydrophobic parameter of the second organic solvent is LogP2, then 0.3≤LogP2-LogP1≤5.

[0006] Furthermore, the hydrophobic parameter LogP1 of the first organic solvent is in the range of -0.4≤LogP1≤2.

[0007] Furthermore, the hydrophobic parameter LogP2 of the second organic solvent is in the range of 2≤LogP2≤5.1.

[0008] Furthermore, the mass ratio M of the first organic solvent to the second organic solvent in the electrolyte is in the range of 3 ≤ M ≤ 17.

[0009] Furthermore, the mass fraction w1 of the first organic solvent in the electrolyte is in the range of 60% ≤ w1 ≤ 85%.

[0010] Furthermore, the mass fraction w2 of the second organic solvent in the electrolyte is in the range of 5% ≤ w2 ≤ 20%.

[0011] Furthermore, the mass fraction w3 of the phase stabilizer in the electrolyte is in the range of 0.05% ≤ w3 ≤ 5%.

[0012] Furthermore, the first organic solvent includes at least one of carbonate solvents and carboxylic acid ester solvents; The second organic solvent includes at least one of fluorocarbonate, fluorophosphate, fluoroether, and fluorophosphazene; The phase stabilizer includes at least one of alkenyl-containing sulfobetaine zwitterionic monomers and alkenyl-containing sodium sulfonate anionic monomers.

[0013] Further, the first organic solvent includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, methyl trifluoroethyl carbonate, 3,3,3-trifluoropropylene carbonate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, and ethyl 2,2-difluoroethyl acetate.

[0014] Furthermore, the number of fluorine atoms in the molecule of the second organic solvent is greater than or equal to 3.

[0015] Further, the second organic solvent includes bis(2,2,2-trifluoroethyl) carbonate, bis(2,2-difluoroethyl) carbonate, bis(2,2,2-trifluoroethyl) phosphite and tris(2,2,2-trifluoroethyl) phosphate, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 1,1,1 At least one of the following: 3,3,3-hexafluoroisopropyl methyl ether, hexafluoropropyltrifluoroethyl ether, 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane, bis(2,2,2-trifluoroethyl) ether, 1,1,2,2-tetrafluoroethyl ethyl ether, tri(trifluoroethoxy)methane, tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane, hexafluorocyclotriphosphazene, pentafluoroethoxycyclotriphosphazene, and pentafluorophenoxycyclotriphosphazene.

[0016] Further, the phase stabilizer comprises at least one of 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt, 1-(3-sulfonopropyl)-4-vinylpyridinium inner salt, N,N-dimethyl-N-acrylamidopropyl-N-propanesulfonic acid inner salt, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 4-((2-(methacryloxy)ethyl)dimethylamino)butane-1-sulfonic acid inner salt, 3-[bis[2-(methacryloxy)ethyl](methyl)ammonium]propane-1-sulfonate, sodium allyl sulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, and sodium 2-(methacryloxy)ethyl sulfonate.

[0017] Secondly, embodiments of this application also provide a single-cell battery, the single-cell battery including a positive electrode, a separator, a negative electrode, and the electrolyte described in embodiments of this application, wherein the separator is disposed between the positive electrode and the negative electrode.

[0018] Thirdly, embodiments of this application also provide an energy storage device, the energy storage device comprising: one or more single-cell batteries as described in embodiments of this application.

[0019] Fourthly, embodiments of this application also provide an electrical system, the electrical system comprising: Electrical equipment; and The energy storage device described in this application embodiment is used to supply power to the electrical equipment. The electrolyte of this application includes a first organic solvent, a second organic solvent, an electrolyte salt, and a phase stabilizer. The first organic solvent and the second organic solvent are interleaved to form their respective continuous network structures. The phase stabilizer is located at the phase interface between the first organic solvent and the second organic solvent. The hydrophobic parameter of the first organic solvent is smaller than that of the second organic solvent. In the relevant electrolyte, solvent molecules and electrolyte salt ions exist in a strongly solvated form of "high proportion of SSIP (solvent-separated ion pairs) + low proportion of CIP (ion pairs)". Due to the addition of a second organic solvent with a large hydrophobic parameter, the solvation structure of the electrolyte salt becomes a weakly solvated structure, achieving an effect similar to a localized high-concentration electrolyte salt. That is, the solvent molecules and electrolyte salt ions in the electrolyte exist in the form of "high proportion of AGG (solvent molecule aggregate structure) and CIP structure + low proportion of SSIP". This structure increases the reducing power of the electrolyte salt anions, allowing the anions to preferentially participate in the construction of the interfacial protective layer. At the same time, it lowers the desolvation energy barrier of the electrolyte salt metal ions (such as lithium ions), making the redox window of the electrolyte wider, alleviating the continuous consumption of the electrolyte during charge-discharge cycles, and mitigating the increase in interfacial impedance of the positive and negative electrode plates, thus extending the cycle life of the single cell. Furthermore, the electrolyte in this application is a bicontinuous interfacially jammed emulsion gel (bijel), which simultaneously possesses the physical properties of both emulsions and gels, exhibiting excellent flowability and stability. Moreover, the bicontinuous emulsion gel does not affect the ionic conductivity of the electrolyte. In summary, the electrolyte of this application combines the kinetic advantages of high conductivity with the electrochemical stability advantages of a wide redox window, thereby significantly extending the cycle life of individual cells without sacrificing the kinetics of the cell itself. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced 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 these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an energy storage system according to an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the structure of an energy storage system according to another embodiment of this application.

[0023] Figure 3 This is a schematic diagram of the structure of an energy storage system according to another embodiment of this application.

[0024] Figure 4 This is a schematic diagram of the structure of an electrical system according to an embodiment of this application.

[0025] Figure 5 This is a schematic diagram of the structure of an energy storage device according to an embodiment of this application.

[0026] Figure 6 This is a schematic diagram of the structure of a single battery cell according to an embodiment of this application.

[0027] Figure 7 For the application of an embodiment of the single cell battery Figure 6 A schematic diagram of the cross-sectional structure along the AA direction.

[0028] Figure 8 For yet another embodiment of the single cell battery, along Figure 6 A schematic diagram of the cross-sectional structure along the AA direction.

[0029] Figure 9 The images show photographs and microstructures of the electrolyte in Example 1. Figure 9 In the image, 'a' represents the electrolyte. Figure 9 Images b and c in the image are laser confocal scanning microscope images of the electrolyte.

[0030] Figure 10 This is a photograph of the electrolyte in Comparative Example 3.

[0031] Explanation of reference numerals in the attached figures: 100 - Energy storage system; 110 - First power conversion device; 120 - First user load; 130 - Second user load; 140 - High-voltage cable; 150 - Second power conversion device; 160 - Photovoltaic-energy storage-charging station; 170 - Automobile; 200 - Energy storage device; 100' - Power system; 110' - Power equipment; 300 - Single cell; 310 - Positive electrode; 320 - Separator; 330 - Negative electrode; 340 - Housing; 341 - Reception cavity; 350 - End cap assembly. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0033] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0034] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0035] It should be noted that, for ease of explanation, the same reference numerals denote the same components in the embodiments of this application, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments.

[0036] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form based on future application needs. Currently, the main way to generate green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels.

[0037] Currently, the generation of green electricity generally relies on solar, wind, and hydropower. However, wind and solar power are generally characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak demand periods, and excessive power during off-peak periods. Unstable voltage can also damage the power grid. Therefore, insufficient electricity demand or insufficient grid capacity may lead to the problem of "wind and solar curtailment." Solving these problems requires energy storage. This involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, this energy can be converted back into electrical energy and released. Simply put, energy storage is like a large "power bank," storing electrical energy when solar and wind power are abundant and releasing the stored electricity when needed.

[0038] Taking electrochemical energy storage as an example, this solution provides an energy storage device for use in energy storage systems. The energy storage device is equipped with a set of chemical batteries, which mainly use the chemical elements in the batteries as energy storage media. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage media. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electricity is released for use, or transferred to places with a shortage of electricity for use.

[0039] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. The corresponding types of energy storage devices include: (1) Large-scale energy storage power stations (composed of multiple prefabricated energy storage modules) applied to wind power and photovoltaic power stations can help renewable energy power generation meet grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power regulation power source on the power supply side, the energy storage power station realizes the load matching of power in time and space, enhances the renewable energy absorption capacity, reduces instantaneous power changes, reduces the impact on the power grid, improves the problem of new energy power generation absorption, and is of great significance in power grid system backup, alleviating peak load power supply pressure and peak regulation and frequency regulation. (2) The energy storage prefabricated cabin applied on the grid side mainly functions as peak regulation, frequency regulation and grid congestion relief. In terms of peak regulation, it can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak electricity load period, thereby achieving a balance between power production and consumption. (3) Small energy storage cabinets applied to the electricity consumption side mainly function as self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improvement of power supply reliability. Depending on the application scenario, electricity consumption side energy storage can be divided into industrial and commercial energy storage cabinets, household energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaics. Industrial and commercial users can use energy storage for peak-valley price arbitrage and capacity cost management. In the electricity market implementing peak-valley pricing, by charging the energy storage system when the electricity price is low and discharging the energy storage system when the electricity price is high, peak-valley price arbitrage can be achieved, reducing electricity costs. In addition, industrial enterprises subject to two-part tariffs can use energy storage systems to store energy during off-peak hours and discharge during peak loads, thereby reducing peak power and the maximum demand declared, achieving the goal of reducing capacity costs. Household photovoltaics with energy storage can improve the level of self-consumption of electricity. Due to high electricity prices and poor power supply stability, the demand for household photovoltaic installations is driven. Given that photovoltaic power generation occurs during the day, while user load is generally higher at night, configuring energy storage can better utilize photovoltaic power, improve self-consumption levels, and reduce electricity costs. Furthermore, energy storage is needed in areas such as communication base stations and data centers for backup power.

[0040] In some embodiments, see Figure 1 , Figure 1 This is a schematic diagram of the structure of an energy storage system 100 according to an embodiment of this application. Figure 1 The embodiments are illustrated using a home energy storage scenario in user-side energy storage as an example. The energy storage device 200 of this application is not limited to the home energy storage scenario.

[0041] This application provides an energy storage system 100, which includes a first power conversion device 110 (photovoltaic panel), a first user load 120 (household lighting fixture), a second user load 130 (e.g., household appliances such as air conditioners), and an energy storage device 200. The energy storage device 200 is a small energy storage box that can be wall-mounted on an outdoor wall. However, the energy storage device 200 is not limited to wall mounting and can also be placed in a user's residence in other ways. Specifically, the photovoltaic panel can convert solar energy into electrical energy during periods of low electricity prices, and the energy storage device 200 stores this electrical energy and supplies it to lighting fixtures and household appliances during peak electricity prices, or provides power during power outages / power interruptions.

[0042] In some embodiments, see Figure 2 , Figure 2 This is a schematic diagram of the structure of an energy storage system 100 according to another embodiment of this application, and this application Figure 2 The embodiments are illustrated using a shared energy storage scenario on the generation / distribution side as an example. The energy storage device 200 of this application is not limited to its generation / distribution side energy storage scenario.

[0043] This application provides an energy storage system 100, which includes: a high-voltage cable 140, a first power conversion device 110, a second power conversion device 150, and an energy storage device 200 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 150 can be a wind power conversion device. Since the electricity generated by wind power conversion is volatile, random, and intermittent, the unstable electricity output by the wind power conversion device can be stored in the energy storage device 200 through grid connection. The energy storage device 200 is connected to the high-voltage cable 140 and outputs smooth electricity to the power consumption side of the distribution network, realizing peak shaving and frequency regulation, and stable grid operation; or, wind power conversion... The power conversion device is always connected to the high-voltage cable 140. Under normal power generation conditions, the power output of the wind power conversion device is supplied to the power consumption side of the distribution network through the high-voltage cable 140. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in the energy storage device 200 to reduce wind and solar curtailment rates and improve the problem of new energy power generation consumption. When the power load is high, the power grid issues an instruction to transmit the power stored in the energy storage device 200 together with the high-voltage cable 140 in grid-connected mode to supply power to the power consumption side. This provides the power grid with various services such as peak shaving, frequency regulation, and backup, giving full play to the peak shaving role of the power grid, promoting peak shaving and valley filling, and alleviating the power supply pressure of the power grid.

[0044] In some embodiments on the distribution network side, the first power conversion device 110 can be a photovoltaic panel, and the energy storage device 200 is connected to the high-voltage cable 140 and installed downstream of the high-voltage cable 140 between the user load and the photovoltaic power conversion device. The electrical energy output by the photovoltaic power conversion device is stored in the energy storage device 200, which can respond in a timely manner to act as a backup power source when the power grid / distribution network fails; or, it can provide power supply support to alleviate line congestion when the high-voltage cable 140 transmission line is blocked, and to delay the economic pressure caused by the expansion of the power grid / distribution capacity when the power grid is planned to be expanded.

[0045] In some embodiments, see Figure 3 , Figure 3 This is a schematic diagram of the structure of an energy storage system 100 according to another embodiment of this application, and this application Figure 3 The embodiments are illustrated using an industrial and commercial energy storage scenario as an example. The energy storage device 200 of this application is not limited to industrial and commercial energy storage scenarios.

[0046] This application provides an energy storage system 100, which includes: an energy storage device 200, a high-voltage cable 140, a factory equipped with a first power conversion device 110, a photovoltaic-energy storage-charging station 160, and a vehicle 170. In some embodiments of industrial and commercial scenarios, the first power conversion device 110 can be a photovoltaic panel, which converts solar energy into electrical energy and stores it in the energy storage device 200 in the factory. In the event of a power grid failure, the energy storage device 200 provides power to ensure the safe and stable operation of the factory without interruption. Alternatively, when the factory's power load is high, the power grid issues an instruction to transmit the electricity stored in the energy storage device 200 in conjunction with the high-voltage cable 140 in a grid-connected mode to supply the factory with electricity, providing various services such as peak shaving / frequency regulation and backup for the power grid operation. In addition, the first power conversion device 110 can also convert solar energy into electrical energy and store it in the energy storage device 200 of the photovoltaic-energy storage-charging station 160, which can directly charge the vehicle 170, making it fast and convenient.

[0047] Optionally, the first power conversion device 110 may include, but is not limited to, a photovoltaic panel, and the second power conversion device 150 may include, but is not limited to, a wind power conversion device. The first power conversion device 110 and the second power conversion device 150 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy, and mechanical energy into electrical energy.

[0048] Figure 4 This is a schematic diagram of the structure of an electrical system 100' according to an embodiment of this application.

[0049] Please see Figure 4 This application embodiment also provides an electrical system 100', which includes an electrical device 110' and an energy storage device 200. The energy storage device 200 is electrically connected to the electrical device 110' and is used to supply power to the energy storage device 200.

[0050] Optionally, the electrical equipment 110' can be, but is not limited to, at least one of the following: power grid, base station, power station, charging station, household appliances (such as air conditioner, refrigerator, washing machine, lighting equipment, etc.).

[0051] Optionally, the electrical equipment 110' and the energy storage device 200 can be electrically connected via a high-voltage cable 140.

[0052] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of an energy storage device 200 according to an embodiment of this application.

[0053] Optionally, the energy storage device 200 includes one or more individual battery cells 300.

[0054] The term "multiple" refers to two or more, such as, but not limited to, 2, 5, 10, 30, 50, 100, 200, 300, 400, 800, 1000, etc. The number of individual battery cells 300 included in the energy storage device 200 can be determined based on the rated capacity of the individual battery cells 300 and the rated capacity to be achieved by the energy storage device 200.

[0055] Optionally, the energy storage device 200 can be used, but is not limited to, energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power systems, and is also applied in multiple fields such as data centers, military equipment, aerospace, charging piles, and electric vehicles.

[0056] Optionally, the energy storage device 200 may include, but is not limited to, battery integrated systems such as single-cell batteries, or battery modules, battery packs, battery clusters, power banks, energy storage cabinets / prefabricated energy storage containers, etc. In other words, when the energy storage device 200 includes a single-cell battery 300, the energy storage device 200 can exist in the form of a single-cell battery 300. When the energy storage device 200 includes multiple single-cell batteries 300, the multiple single-cell batteries 300 can be stacked, arranged, assembled, etc., to form battery integrated systems such as battery modules, battery packs, battery clusters, power banks, energy storage cabinets / energy storage containers; that is, the energy storage device 200 exists in the form of battery integrated systems such as battery modules, battery packs, battery clusters, power banks, energy storage cabinets / energy storage containers, etc. The actual application form of the energy storage device 200 provided in this application embodiment can be, but is not limited to, the listed products, and can also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 200. This application embodiment only illustrates the case where the energy storage device 200 is a multi-cell battery (i.e., multiple single-cell batteries 300).

[0057] Optionally, the single cell 300 can be, but is not limited to, at least one of cylindrical, square, prismatic, or other shaped cells.

[0058] Optionally, the single cell 300 can be a rechargeable battery, which refers to a single cell 300 that can be recharged after discharge to activate the active materials and continue to be used. The single cell 300 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application does not specifically limit it.

[0059] Understandably, the 300 single cell can be, but is not limited to, sodium batteries, lithium batteries, magnesium batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0060] Figure 6 This is a schematic diagram of the structure of a single cell battery 300 according to an embodiment of this application. Figure 7 For an embodiment of the application, a single cell 300 is applied for. Figure 6 A schematic diagram of the cross-sectional structure along the AA direction. Figure 8 For yet another embodiment of the single cell 300, Figure 6 A schematic diagram of the cross-sectional structure along the AA direction.

[0061] Please see Figures 6 to 8 This application provides a single-cell battery 300, which includes a positive electrode 310, a separator 320, a negative electrode 330 and an electrolyte, wherein the separator 320 is disposed between the positive electrode 310 and the negative electrode 330.

[0062] Understandably, the positive electrode 310 and the negative electrode 330 are located on opposite sides of the separator 320, that is, the separator 320 is located between the positive electrode 310 and the negative electrode 330, separating the positive electrode 310 and the negative electrode 330.

[0063] It should be noted that the positive electrode 310, the separator 320, and the negative electrode 330 are all at least partially immersed in the electrolyte.

[0064] It should be noted that the positive electrode 310 and the negative electrode 330 can be collectively referred to as electrode plates.

[0065] It should be noted that the battery cell comprises a positive electrode 310, a separator 320, and a negative electrode 330. Optionally, the battery cell can be at least one of a wound battery cell or a stacked battery cell. The single cell 300 can be either a wound battery or a stacked battery.

[0066] like Figure 7 As shown, in one example, the single-cell battery 300 is a wound battery, and the cell is a wound cell. The positive electrode 310, the separator 320, and the negative electrode 330 are stacked sequentially and then wound to obtain the battery. Figure 8 As shown, in another example, the single cell 300 is a stacked cell, and the cell is a stacked cell. The cell includes multiple positive electrode plates 310, multiple separators 320 and multiple negative electrode plates 330. The positive electrode plates 310 and negative electrode plates 330 are stacked alternately in sequence, and a separator 320 is provided between adjacent positive electrode plates 310 and negative electrode plates 330.

[0067] Please see again Figures 6 to 8Optionally, the single-cell battery 300 further includes a housing 340 and an end cap assembly 350. The housing 340 and the end cap assembly 350 form a closed receiving cavity 341 for housing the electrolyte, the positive electrode 310, the separator 320, and the negative electrode 330. Understandably, the end cap assembly 350 electrically connects the positive electrode 310 and the negative electrode 330, leading them out for electrical connection to external devices or other single-cell batteries 300.

[0068] Currently, carbonates and carboxylic esters are the main solvents in commercial lithium-ion battery electrolytes due to their wide operating temperature window, superior polarity, stable supply, and low cost. However, in battery systems using graphite and silicon as anode materials, these solvents have a narrow electrochemical stability window. As the active material expands and contracts during charging and discharging, electrolyte decomposition reactions continue to occur at the newly exposed interfaces, consuming electrolyte and active lithium, thus reducing the battery's cycle life.

[0069] This application provides an electrolyte comprising a first organic solvent, a second organic solvent, an electrolyte salt, and a phase stabilizer. The first organic solvent and the second organic solvent are interleaved to form their respective continuous network structures. The phase stabilizer is located at the phase interface between the first organic solvent and the second organic solvent. The hydrophobic parameter of the first organic solvent is smaller than that of the second organic solvent. The electrolyte salt is dissolved in both the first organic solvent and the second organic solvent.

[0070] Understandably, the first organic solvent, the second organic solvent, and the phase stabilizer form a bicontinuous interfacially jammed emulsion gel (Bijel for short).

[0071] It should be noted that the first organic solvent and the second organic solvent are interspersed with each other, yet each is continuous.

[0072] It should be noted that the first organic solvent and the second organic solvent are macroscopically mutually soluble—that is, no stratification is observed in the mixed solution with the naked eye—but they are microscopically immiscible—that is, the two-phase structure that does not mix can be observed at the nanoscale using an electron microscope.

[0073] Optionally, the solubility of the electrolyte salt in the first organic solvent is greater than that in the second organic solvent.

[0074] Optionally, the first organic solvent is a low-hydrophobic organic solvent, and the second organic solvent is a high-hydrophobic organic solvent.

[0075] It should be noted that the bicontinuous emulsion-gel phase of the electrolyte in this application can be measured using optical microscopy or Raman microscopy. That is, the distribution of the first and second organic solvents in the electrolyte can be qualitatively determined using optical microscopy or Raman microscopy. Taking Raman mapping as an example, the instrument conditions are: laser wavelength 532 nm or 633 nm, spatial resolution ≤ 1 μm, and spectral range 200 cm⁻¹. -1 -2000cm -1 The electrolyte was dropped directly onto a glass slide and sealed with a coverslip to prevent evaporation. The instrument was set to a scan step size of 0.5 μm and an integration time of 3 s per point, and point-by-point spectral acquisition was performed on the target area. Multivariate analysis methods (such as MCR, PCA) or characteristic peak integration were used, combined with the characteristic peak positions of each solvent, to extract the contribution of each solvent component from the spectral data and generate a distribution map.

[0076] The electrolyte of this application includes a first organic solvent, a second organic solvent, an electrolyte salt, and a phase stabilizer. The first organic solvent and the second organic solvent interweave to form their respective continuous network structures, and the phase stabilizer is located at the phase interface between the first organic solvent and the second organic solvent. The hydrophobic parameter of the first organic solvent is smaller than that of the second organic solvent. In conventional electrolytes, solvent molecules and electrolyte salt ions exist in a strongly solvated form of "high proportion SSIP (solvent-separated ion pairs) + low proportion CIP (ion pairs)". Due to the addition of the second organic solvent with a larger hydrophobic parameter, the solvation structure of the electrolyte salt becomes a weakly solvated structure, achieving an effect similar to a locally high concentration of electrolyte salt—that is, the solvent molecules and electrolyte salt ions in the electrolyte exist in the form of "high proportion AGG (aggregate structure of solvent molecules) and CIP structure + low proportion SSIP". This structure increases the electrolyte salt's... The reducing power of anions allows them to preferentially participate in the construction of the interfacial protective layer; simultaneously, it lowers the desolvation energy barrier of the electrolyte salt's metal ions (e.g., lithium ions), widening the electrolyte's redox window and mitigating continuous electrolyte consumption during charge-discharge cycles. It also reduces the increase in impedance at the interfaces between the positive electrode 310 and the negative electrode 330 (e.g., the solid electrolyte interphase (SEI) film of the negative electrode 330 and the positive electrode electrolyte interphase (CEI) film of the positive electrode 310), thus extending the cycle life of the single-cell battery 300. Furthermore, the electrolyte of this application is a bicontinuous interfacially jammed emulsion gel (bijel), which possesses the physical properties of both emulsions and gels, exhibiting good fluidity and stability. Moreover, the bicontinuous emulsion gel does not affect the ionic conductivity of the electrolyte. In summary, the electrolyte proposed is a bicontinuous emulsion gel that combines the kinetic advantages of high conductivity with the electrochemical stability advantages of a wide redox window, thereby significantly extending the cycle life of the single cell 300 without sacrificing the kinetics of the single cell 300.

[0077] In some embodiments, the hydrophobic parameter of the first organic solvent is LogP1 and the hydrophobic parameter of the second organic solvent is LogP2, then 0.3≤LogP2-LogP1≤5.

[0078] It should be noted that the LogP1 of the first organic solvent and the LogP2 of the second organic solvent are both calculated using XLogP3 (XLogP3 3.0); they can also be obtained by querying PubChem. The hydrophobic parameter XLogP3 is a measure of the magnitude of a molecule's hydrophobicity and is used to predict the partition coefficient of a molecule between aqueous and non-aqueous phases.

[0079] Specifically, LogP2-LogP1 can be, but is not limited to, 0.3, 0.5, 0.8, 1.0, 1.3, 1.5, 1.8, 2.0, 2.3, 2.5, 2.8, 3.0, 3.3, 3.5, 3.8, 4.0, 4.3, 4.5, 4.8, etc.

[0080] In this embodiment, if LogP2-LogP1 is too small, the first organic solvent and the second organic solvent may mix at the microscopic level, making it difficult to form a bicontinuous emulsion gel. If LogP2-LogP1 is too large, the difference in hydrophobicity between the first organic solvent and the second organic solvent is too great, making it easy for stratification to occur, and similarly making it difficult to form a bicontinuous emulsion gel.

[0081] In some embodiments, the hydrophobic parameter LogP1 of the first organic solvent is in the range of -0.4≤LogP1≤2.

[0082] Specifically, the hydrophobic parameter LogP1 of the first organic solvent can be, but is not limited to, -0.4, -0.2, 0, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, etc.

[0083] In this embodiment, if the hydrophobic parameter LogP1 of the first organic solvent is too small, the hydrophobicity of the first organic solvent is weak, making the miscibility of the first organic solvent with the highly hydrophobic second organic solvent very poor. At the microscopic level, the two phases cannot be stabilized. Although they may dissolve after mechanical stirring and shaking, they are very prone to stratification, making it difficult to form a bicontinuous emulsion gel. If the hydrophobic parameter LogP1 of the first organic solvent is too large, the hydrophobicity of the first organic solvent and the second organic solvent is too similar. At the microscopic level, there is no obvious phenomenon of independent aggregation of the two phases, making it difficult to form a bicontinuous emulsion gel.

[0084] In some embodiments, the hydrophobic parameter LogP2 of the second organic solvent is in the range of 2≤LogP2≤5.1.

[0085] Specifically, the hydrophobic parameter LogP2 of the second organic solvent can be, but is not limited to, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.1, etc.

[0086] In this embodiment, if the hydrophobic parameter LogP2 of the second organic solvent is too small, the hydrophobicity of the first and second organic solvents is too similar. At the microscopic level, the two phases mix without significant independent aggregation, making it difficult to form a bicontinuous emulsion gel. If the hydrophobic parameter LogP2 of the second organic solvent is too large, the miscibility of the low-hydrophobic first and second organic solvents is very poor, and the microscopic level cannot stabilize the two phases. Although they may dissolve after mechanical stirring and shaking, they are very prone to stratification, again making it difficult to form a bicontinuous emulsion gel.

[0087] In some embodiments, the mass ratio M of the first organic solvent to the second organic solvent in the electrolyte is in the range of 3 ≤ M ≤ 17.

[0088] Specifically, the mass ratio M of the first organic solvent to the second organic solvent in the electrolyte can be, but is not limited to, 3, 5, 6, 8, 10, 12, 14, 16, 17, etc.

[0089] In this embodiment, if the mass ratio M of the first organic solvent to the second organic solvent in the electrolyte is too small, the content of the second organic solvent in the electrolyte will be too high. This will easily lead to phase separation, stratification, or gelation between the first and second organic solvents, which is detrimental to the formation of a bicontinuous emulsion gel. Conversely, if the mass ratio M of the first organic solvent to the second organic solvent in the electrolyte is too large, the content of the second organic solvent in the electrolyte will be too low. This will also easily lead to phase separation, stratification, or gelation between the first and second organic solvents, which is also detrimental to the formation of a bicontinuous emulsion gel.

[0090] In some embodiments, the mass fraction w1 of the first organic solvent in the electrolyte is in the range of 60% ≤ w1 ≤ 85%.

[0091] It should be noted that, in the following descriptions of this application, when percentages, percentages, percentage content, % etc. are involved, unless otherwise specified, they all refer to mass percentages and mass fractions.

[0092] Specifically, the mass fraction w1 of the first organic solvent in the electrolyte can be, but is not limited to, 60%, 63%, 65%, 68%, 70%, 73%, 75%, 78%, 80%, 83%, 85%, etc. In this embodiment, if the mass fraction w1 of the first organic solvent in the electrolyte is too low, the mass fraction w2 of the second organic solvent in the electrolyte will be too high. Phase separation, stratification, or gelation will easily occur between the first and second organic solvents, which is detrimental to the formation of a bicontinuous emulsion gel. Similarly, if the mass fraction w1 of the first organic solvent in the electrolyte is too high, the mass fraction w2 of the second organic solvent in the electrolyte will be too low, which will also make phase separation, stratification, or gelation easy to occur between the first and second organic solvents, which is also detrimental to the formation of a bicontinuous emulsion gel.

[0093] In some embodiments, the mass fraction w2 of the second organic solvent in the electrolyte is in the range of 5% ≤ w2 ≤ 20%.

[0094] Specifically, the mass fraction w1 of the second organic solvent in the electrolyte can be, but is not limited to, 5%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, etc. In this embodiment, if the mass fraction w2 of the second organic solvent in the electrolyte is too low, the mass fraction w1 of the first organic solvent in the electrolyte will be too high, making it easy for phase separation to occur between the first and second organic solvents, leading to stratification or gelation, which is detrimental to the formation of a bicontinuous emulsion gel. Conversely, if the mass fraction w2 of the second organic solvent in the electrolyte is too high, the mass fraction w1 of the first organic solvent in the electrolyte will be too low, making it easy for phase separation to occur between the first and second organic solvents, leading to stratification or gelation, which is detrimental to the formation of a bicontinuous emulsion gel.

[0095] In some embodiments, the mass fraction w3 of the phase stabilizer in the electrolyte is in the range of 0.05% ≤ w3 ≤ 5%.

[0096] Specifically, the mass fraction w1 of the phase stabilizer in the electrolyte can be, but is not limited to, 0.05%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 2%, 3%, 4%, 5%, etc.

[0097] In this embodiment, if the mass fraction w3 of the phase stabilizer in the electrolyte is too low, the content of the phase stabilizer in the electrolyte is insufficient to adequately block the first organic solvent and the second organic solvent. This causes the first organic solvent and the second organic solvent to easily aggregate, making it difficult to form an interpenetrating, intertwined, and continuous network structure. If the mass fraction w3 of the phase stabilizer in the electrolyte is too high, the first organic solvent and the second organic solvent are prone to forming a discontinuous two-phase structure, making it difficult to form a bicontinuous emulsion gel structure.

[0098] In some embodiments, the first organic solvent includes at least one of carbonate solvents and carboxylic acid ester solvents; the second organic solvent includes at least one of fluorocarbonate, fluorophosphate, fluoroether, and fluorophosphazene; and the phase stabilizer includes at least one of alkenyl-containing sulfobetaine zwitterionic monomers and alkenyl-containing sodium sulfonate anionic monomers.

[0099] Optionally, the carbonate solvent can be a fluorine-free substituted solvent or a carbonate solvent having one to three fluorine atoms. The carboxylic acid ester solvent can be a fluorine-free substituted solvent or a carboxylic acid ester solvent having one to three fluorine atoms.

[0100] In this embodiment, carbonate solvents and carboxylic acid ester solvents have a wide operating temperature window and strong hydrophilicity (low hydrophobicity), while fluorocarbonates, fluorophosphates, fluoroethers, and fluorophosphazenes have low hydrophilicity (strong hydrophobicity), which is beneficial for the formation of a bicontinuous phase. Furthermore, alkenyl-containing sulfobetaine zwitterionic monomers and alkenyl-containing sodium sulfonate anionic monomers can effectively separate the first organic solvent and the second organic solvent during electrolyte preparation, promoting the formation of a bicontinuous emulsion gel. When the electrolyte is injected into the bare cell to form a single cell 300, the alkenyl-containing sulfobetaine zwitterionic monomers and alkenyl-containing sodium sulfonate anionic monomers contain alkenyl groups, which partially undergo polymerization reactions in the single cell 300 to form oligomers. This further separates the first organic solvent and the second organic solvent and maintains the stability of the phase interface, making the bicontinuous emulsion gel of the electrolyte more stable during use and contributing to a longer cycle life for the single cell 300. In addition, alkenyl-containing sulfobetaine zwitterionic monomers and alkenyl-containing sodium sulfonate anionic monomers can also partially decompose and participate in the formation of nitrogen (N) and sulfur (S) inorganic components in the SEI and CEI films, which is beneficial to improving the stability of the SEI and CEI films of the single cell battery 300 and improving the cycle performance of the single cell battery 300.

[0101] Optionally, the relative molecular mass of the first organic solvent is less than or equal to 160 g / mol, and the relative molecular mass of the second organic solvent is greater than or equal to 140 g / mol.

[0102] In some embodiments, the first organic solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl propyl carbonate (MPC), methyl trifluoroethyl carbonate (FEMC), 3,3,3-trifluoropropylene carbonate (TFPC), ethyl acetate (EA), propyl acetate (EP), ethyl propionate, propyl propionate (PP), and ethyl 2,2-difluoroethyl acetate (DFEA).

[0103] Optionally, the carbonate solvent may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl propyl carbonate (MPC), methyl trifluoroethyl carbonate (FEMC), and 3,3,3-trifluoropropylene carbonate (TFPC).

[0104] Optionally, the carboxylic acid ester solvent may be, but is not limited to, at least one of ethyl acetate (EA), propyl acetate (EP), ethyl propionate, propyl propionate (PP), ethyl 2,2-difluoroacetate (DFEA), etc.

[0105] In this embodiment, these organic solvents have high hydrophilicity (low hydrophobicity), which is beneficial for forming a bicontinuous emulsion gel with the second organic solvent. In addition, they can better dissolve electrolyte salts. Furthermore, these organic solvents have good low-temperature performance and good wettability to the positive electrode 310, separator 320 and negative electrode 330, which can better reduce the internal resistance of the single cell 300.

[0106] In some embodiments, the number of fluorine atoms in the molecule of the second organic solvent is greater than or equal to 3. Specifically, the number of fluorine atoms in the molecule of the second organic solvent can be, but is not limited to, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. In this embodiment, the molecule of the second organic solvent has a relatively large number of fluorine atoms, thereby giving the second organic solvent weak hydrophilicity (strong hydrophobicity), which is beneficial for the formation of a stable bicontinuous emulsion gel between the first organic solvent and the second organic solvent, and is beneficial for improving the cycle life of the single cell 300.

[0107] In some embodiments, the second organic solvent includes bis(2,2,2-trifluoroethyl) carbonate (TFEC), bis(2,2-difluoroethyl) carbonate, bis(2,2,2-trifluoroethyl) phosphite, tris(2,2,2-trifluoroethyl) phosphate (TFEP), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE-458), 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (HFE-6512), and 1,1,1,3,3,3-hexafluoroisopropyl At least one of the following: methyl ether (HFMOP), hexafluoropropyltrifluoroethyl ether (HFE449), 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane (HFE-578E), bis(2,2,2-trifluoroethyl) ether, 1,1,2,2-tetrafluoroethyl ethyl ether (HFE-374), tri(trifluoroethoxy)methane, tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane (HFE-347), hexafluorocyclotriphosphazene, pentafluoroethoxycyclotriphosphazene (PFPN), and pentafluorophenoxycyclotriphosphazene (FPPN).

[0108] Optionally, the fluorocarbonate may be, but is not limited to, at least one of bis(2,2,2-trifluoroethyl)carbonate (TFEC) and bis(2,2-difluoroethyl)carbonate.

[0109] Optionally, the fluorophosphate may be, but is not limited to, at least one of bis(2,2,2-trifluoroethyl) phosphite and tris(2,2,2-trifluoroethyl) phosphate (TFEP).

[0110] Optionally, the fluoroether can be, but is not limited to, at least one of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE-458), 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (HFE-6512), 1,1,1,3,3,3-hexafluoroisopropylmethyl ether (HFMOP), hexafluoropropyltrifluoroethyl ether (HFE449), 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane (HFE-578E), bis(2,2,2-trifluoroethyl) ether, 1,1,2,2-tetrafluoroethyl ether (HFE-374), tri(trifluoroethoxy)methane, and tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane (HFE-347).

[0111] Optionally, the fluorophosphazene can be, but is not limited to, at least one of hexafluorocyclotriphosphazene, pentafluoroethoxycyclotriphosphazene (PFPN), and pentafluorophenoxycyclotriphosphazene (FPPN).

[0112] In this embodiment, the molecules of these organic solvents have a large number of fluorine atoms, which makes the second organic solvent weakly hydrophilic (strongly hydrophobic), which is conducive to the formation of a stable bicontinuous emulsion gel between the first organic solvent and the second organic solvent, and is beneficial to improving the cycle life of the single cell 300.

[0113] The hydrophobic parameters XLogP3 of the first and second organic solvents are shown in Table 1 and Table 2, respectively.

[0114] Table 1. Hydrophobic parameters of the first organic solvent: XLogP3 (LogP1)

[0115] Table 2. Hydrophobic parameters of the second organic solvent: XLogP3 (LogP2)

[0116] In some embodiments, the phase stabilizer includes 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt (CAS: 6613-64-5), 1-(3-sulfonopropyl)-4-vinylpyridinium inner salt (CAS: 4271-44-7), N,N-dimethyl-N-acrylamidopropyl-N-propanesulfonic acid inner salt (CAS: 40623-75-4), 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt (CAS: 3637-26-1), 4 At least one of the following: -((2-(methacryloyloxy)ethyl)dimethylamino)butane-1-sulfonic acid inner salt (CAS: 6613-65-6), 3-[bis[2-(methacryloyloxy)ethyl](methyl)ammonium]propane-1-sulfonate (CAS: 1314713-40-0), sodium allyl sulfonate (CAS: 2495-39-8), sodium 2-acrylamido-2-methylpropanesulfonate (CAS: 15214-89-8), and sodium 2-(methacryloyloxy)ethyl sulfonate (CAS: 1804-87-1).

[0117] Optionally, the alkenyl-containing sulfobetaine zwitterionic monomers can be, but are not limited to, 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt (CAS: 6613-64-5), 1-(3-sulfonopropyl)-4-vinylpyridinium inner salt (CAS: 4271-44-7), N,N-dimethyl-N-acrylamidopropyl-N-propanesulfonic acid inner salt (CAS: 40623-75-4), 3-[N,N-dimethyl-N-acrylamidopropyl-N-propanesulfonic acid inner salt, etc. At least one of the following: 4-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate (CAS: 3637-26-1), 4-((2-(methacryloyloxy)ethyl)dimethylamino)butane-1-sulfonate (CAS: 6613-65-6), and 3-[bis[2-(methacryloyloxy)ethyl](methyl)ammonium]propane-1-sulfonate (CAS: 1314713-40-0).

[0118] Optionally, the alkenyl-containing sodium sulfonate anionic monomer may be, but is not limited to, at least one of sodium allyl sulfonate (CAS: 2495-39-8), sodium 2-acrylamido-2-methylpropanesulfonate (CAS: 15214-89-8), and sodium 2-(methacryloyloxy)ethyl sulfonate (CAS: 1804-87-1).

[0119] In this embodiment, these phase stabilizers effectively separate the first and second organic solvents during electrolyte preparation, forming a bicontinuous emulsion gel. Furthermore, these phase stabilizers contain alkenyl groups, which partially polymerize within the cell 300 to form oligomers, thereby maintaining the stability of the phase interface. This results in a more stable bicontinuous emulsion gel of the electrolyte during use, contributing to a longer cycle life for the cell 300. Additionally, the phase stabilizers can partially decompose and participate in the formation of nitrogen (N) and sulfur (S) inorganic components in the SEI and CEI films, further improving the stability of the SEI and CEI films and enhancing the cycle performance of the cell 300.

[0120] Optionally, the electrolyte salt may be, but is not limited to, at least one of lithium salt and sodium salt.

[0121] Optionally, the lithium salt includes at least one of lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalateborate)borate (LiBOB), lithium difluorodioxalate phosphate (LiDFOP), lithium difluorooxalate borate (LiDFOB), lithium (2-fluoromalonate)difluoroborate (LIFMDFB), lithium difluorophosphate (LiPO2F2), and lithium trifluoromethanesulfonate (CF3SO3Li).

[0122] Optionally, the sodium salt includes at least one of sodium hexafluorophosphate (NaPF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium tetrafluoroborate (NaBF4), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium bis(oxalateborate)borate (NaBOB), sodium difluorodioxalate phosphate (NaDFOP), sodium difluorooxalate borate (NaDFOB), sodium (2-fluoromalonate)difluoroborate (NAFMDFB), sodium difluorophosphate (NaPO2F2), and sodium trifluoromethanesulfonate (CF3SO3Na).

[0123] Optionally, the mass fraction w4 of the electrolyte salt in the electrolyte is in the range of 5% ≤ w4 ≤ 20%. Specifically, the mass fraction w4 of the electrolyte salt in the electrolyte can be, but is not limited to, 5%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, etc.

[0124] Understandably, the molar concentration of the electrolyte salt in the electrolyte solution is from 0.3 mol / L to 2 mol / L. In the embodiments of this application, when referring to the numerical range x to y, unless otherwise specified, it means that the value can be any value between x and y, including the endpoint value x and the endpoint value y.

[0125] Optionally, the electrolyte further includes film-forming additives. Optionally, the film-forming additives include at least one selected from fluoroethylene carbonate (FEC), ethylene sulfate (DTD), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), tris(trimethylsilane) phosphate (TMSP), tris(trimethylsilane) borate, adiponitrile, succinic anhydride, and 1,3,6-hexanetrionitrile.

[0126] Optionally, the electrolyte in the embodiments of this application is in a clear and transparent state, or in a semi-transparent state.

[0127] Optionally, the turbidity value of the electrolyte ranges from 0 to 300 NTU. Specifically, the turbidity value of the electrolyte can be, but is not limited to, 0, 10 NTU, 30 NTU, 50 NTU, 80 NTU, 100 NTU, 130 NTU, 150 NTU, 180 NTU, 200 NTU, 230 NTU, 250 NTU, 280 NTU, 300 NTU, etc. Turbidity value testing: The turbidity value of the prepared electrolyte is tested using an optical turbidimeter (range 0-1000 NTU, accuracy 1 NTU).

[0128] This application also provides a method for preparing an electrolyte, the method comprising: (1) Provide a first organic solvent, an electrolyte salt and a film-forming additive, and dissolve the electrolyte salt and the film-forming additive in the first organic solvent to obtain a first solution; (2) Providing a second organic solvent and a phase stabilizer, and dissolving the phase stabilizer in the second organic solvent to obtain a second solution; and (3) Under stirring, the second solution is slowly added to the first solution, and after mechanical stirring or ultrasonic mixing, the electrolyte of the bicontinuous emulsion gel is obtained.

[0129] It should be noted that the uniform dispersion of the two phases can be well controlled by adjusting the rate at which the second solution is added to the first solution and the stirring rate.

[0130] It should be noted that, in other embodiments, the film-forming additive may also be dissolved together with the phase stabilizer in a second organic solvent.

[0131] It should be noted that for detailed descriptions of other aspects of the first organic solvent, the second organic solvent, the phase stabilizer, the electrolyte salt, and the film-forming additives, please refer to the descriptions in the corresponding sections of the above embodiments, which will not be repeated here.

[0132] The electrolyte preparation method of this application involves dissolving the electrolyte salt and the phase stabilizer in a first organic solvent and a second organic solvent, respectively. This method can prevent the electrolyte salt from affecting the dissolution of the phase stabilizer and avoids the difficulty of subsequent stirring caused by direct mixing, which makes it difficult to form a dispersed and stable bicontinuous emulsion gel electrolyte.

[0133] It should be noted that the composition and content of each component of the electrolyte in this application can be measured by gas chromatography-mass spectrometry (GC-MS). After the electrolyte is assembled into the single cell 300, the electrolyte is first separated by centrifugation, and then measured by GC-MS.

[0134] The following detailed description of the single-cell battery 300 (lithium-ion battery) and electrolyte of this application provides further details through specific embodiments. In the following embodiments, the single-cell battery 300 is described using a lithium-ion battery as an example and should not be construed as limiting the single-cell battery 300 of the embodiments of this application.

[0135] Examples 1 to 18, Comparative Examples 1 to 10 The lithium-ion batteries of each embodiment and comparative embodiment were prepared by the following steps: (1) Preparation of positive electrode 310: Commercially available positive electrode active materials lithium iron phosphate (LFP), polyvinylidene fluoride (PVDF, binder), and conductive carbon black (SP) were dispersed in the solvent N-methylpyrrolidone (NMP) at a mass ratio of 97:2.5:0.5 and mixed evenly to obtain a positive electrode slurry. The positive electrode slurry was coated on the positive electrode current collector aluminum foil, and the coating weight per unit area of ​​the positive electrode slurry was 33 mg / cm². 2 After embossing, drying, cold pressing, slitting, and cutting, the positive electrode sheet 310 is obtained.

[0136] (2) Preparation of negative electrode sheet 330: The negative electrode active material artificial graphite, conductive carbon black (SP), thickener (sodium carboxymethyl cellulose, CMC) and binder (styrene-butadiene rubber, SBR) were dispersed in deionized water at a mass ratio of 96.5:0.5:1:2 and mixed evenly to obtain a negative electrode slurry. The negative electrode slurry was coated on the negative electrode current collector, and the coating weight per unit area of ​​the negative electrode slurry was 16 mg / cm². 2 After drying, cold pressing, slitting, and cutting, negative electrode sheet 330 is obtained.

[0137] (3) Electrolyte preparation: Electrolytes for each example and comparative example were prepared in an argon atmosphere glove box with moisture and oxygen content ≤0.1ppm. The total mass of the electrolyte prepared in each group was 1kg. Specifically: Electrolyte of Comparative Example 1: EC (first organic solvent), EMC (first organic solvent), and DMC (first organic solvent) were mixed in a mass ratio of 1:1:1. Then, LiPF6 (lithium salt), LiFSI (lithium salt), VC (film-forming additive), FEC (film-forming additive), DTD (film-forming additive), TMSP (film-forming additive), and 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt (phase stabilizer) were added sequentially and stirred until completely dissolved to obtain the electrolyte. The electrolyte of Comparative Example 1, by mass fraction, included 10% LiPF6, 5% LiFSI, 2.5% VC, 1% FEC, 0.5% DTD, 0.5% TMSP, 0.5% 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt, and 80% first organic solvent.

[0138] Electrolyte of Comparative Example 2: EC, EMC, and DMC were mixed in a mass ratio of 1:1:1. HFE-458 (second organic solvent), LiPF6, LiFSI, VC, FEC, DTD, and TMSP were added sequentially and stirred until completely dissolved. The electrolyte of Comparative Example 2, by mass fraction, included 15.5% HFE-458 (second organic solvent), 10% LiPF6, 5% LiFSI, 2.5% VC, 1% FEC, 0.5% DTD, 0.5% TMSP, and 65% first organic solvent.

[0139] Electrolyte of Comparative Example 3: The first organic solvent EC, EMC, and DMC were mixed in a mass ratio of 1:1:1. HFE-458 (second organic solvent), LiPF6, LiFSI, VC, FEC, DTD, TMSP, and 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt (phase stabilizer) were added sequentially and stirred until completely dissolved to obtain the electrolyte. The electrolyte of Comparative Example 3, by mass fraction, included 15% HFE-458, 10% LiPF6, 5% LiFSI, 2.5% VC, 1% FEC, 0.5% DTD, 0.5% TMSP, 0.5% 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt, with the balance being the first organic solvent.

[0140] Electrolyte of Example 1: ① The first organic solvents EC, EMC, and DMC were mixed in a mass ratio of 1:1:1. Then, LiPF6, LiFSI, VC, FEC, DTD, and TMSP were added sequentially and stirred until homogeneous to obtain a first solution. ② 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt (phase stabilizer) was added to the second organic solvent HFE-458 and stirred until homogeneous to obtain a second solution. ③ The second solution was slowly added to the first solution and ultrasonically mixed for 10 minutes to obtain the electrolyte of Example 1. The electrolyte of Example 1, by mass fraction, includes 15% HFE-458, 10% LiPF6, 5% LiFSI, 2.5% VC, 1% FEC, 0.5% DTD, 0.5% TMSP, 0.5% 1-(3-sulfonopropyl)-2-vinylpyridinium inner salt, and 65% of the first organic solvent.

[0141] The electrolyte preparation order, film-forming additives, and lithium salts of Comparative Examples 4, 6 to 7, and 2 to 18 were the same as those of Example 1. The differences lay in the type and mass fraction of the first organic solvent, the type and mass fraction of the second organic solvent, the type and mass fraction of the phase stabilizer, and the type and mass content of the first organic solvent, the second organic solvent, and the special additives used in each group. It should be noted that when the first organic solvent includes at least two types, the at least two first organic solvents are mixed in equal mass ratios; when the second organic solvent includes at least two types, the at least two second organic solvents are mixed in equal mass ratios. The types and mass fractions of the first organic solvent, second organic solvent, and phase stabilizer for each example and comparative example are shown in Table 3 below.

[0142] The preparation method of the electrolyte in Comparative Example 5 is the same as that in Example 1, except that the composition of the electrolyte is different. The electrolyte in Comparative Example 5 includes, by mass fraction: 15% HFE-458 (second organic solvent), 7% LiPF6, 2.5% VC, 0.5% 1-(3-sulfonylpropyl)-2-vinylpyridinium inner salt, and the balance being the first organic solvent.

[0143] Electrolyte for Comparative Example 8: Prepare a 4 mol / L LiPF6-PC electrolyte. Weigh the LiPF6-PC electrolyte and ethylbenzene at a mass ratio of 4:6 and mix them to form an immiscible two-phase system. Add 10% by mass of tributyl phosphate as a surfactant to form a homogeneous organic microemulsion electrolyte.

[0144] Comparative Example 9 Electrolyte: First, prepare a 4 mol / L LiFSI-TMP (trimethyl phosphate) electrolyte. Weigh out the LiFSI-TMP electrolyte and pentafluoroethoxycyclotriphosphazene (PFPN) in a mass ratio of 4:6, and mix them to form an immiscible two-phase system. While stirring, add 10% tris(2,2,2-trifluoroethyl) phosphate (TFEP) dropwise as a surfactant to this system.

[0145] Electrolyte of Comparative Example 10: EMC and FEC were mixed in a volume ratio of 2:1, and LiDFOB and LiBF4 were added to obtain a first-phase solution of 1 mol / L LiDFOB and 0.2 mol / L LiBF4. 5 vol.% of perfluorohexyl sulfonyl fluoride (insoluble phase) was added to the first-phase solution. Then, tris(2,2,2-trifluoroethyl)borate ester was added dropwise as a bridging phase solvent while stirring to obtain a mixed-phase electrolyte, wherein the volume ratio of the first phase / insoluble phase / bridging phase was 100:5:30. Finally, 1% vinyldimethylfluorosilane was added to the above electrolyte.

[0146] (4) The diaphragm 320 includes a polyethylene porous substrate (PE) and a ceramic coating disposed on two opposite surfaces of the polyethylene porous substrate. The polyethylene porous substrate (PE) has a thickness of 7 μm and the ceramic coating has a thickness of 1.5 μm. The ceramic coating includes alumina and polyvinylidene fluoride (PVDF).

[0147] (5) Assembly of lithium-ion battery (single cell 300): The above-mentioned positive electrode 310, separator 320 and negative electrode 330 are stacked in sequence, so that the separator 320 is between the positive electrode 310 and the negative electrode 330. It is wound into a bare cell, and after welding the tabs, it is hot-pressed and vacuum dried. Then, it is injected with liquid, packaged, placed, formed, and capacity tested, and finally a soft-pack lithium-ion battery with a capacity of about 3.2Ah is prepared. Among them, the lithium-ion battery formation adopts the following process: Step 1: The unformed lithium-ion battery is placed in a 45°C formation cabinet for 10 min, and charged at 0.1C rate for 7 min to 1.17% SOC; Step 2: Placed for 3 min, charged at 0.2C rate to 30% SOC.

[0148] The following performance tests were performed on the lithium-ion batteries of each embodiment and comparative example: (1) Turbidity test: The turbidity of the prepared electrolyte was tested using an optical turbidimeter (range 0-1000 NTU, accuracy 1 NTU).

[0149] (2) Cyclic life test: The lithium-ion battery was discharged to 2.5V at a constant power of 1P in a constant temperature environment of 45±5℃, allowed to rest for 10 minutes, and then charged to 3.65V at a constant power of 1P. After resting for 10 minutes, this charge-discharge cycle was repeated, and the discharge capacity (DC) of each cycle was recorded. x Calculate the ratio of the discharge capacity in the nth cycle to the initial discharge capacity in the third cycle, i.e., the capacity retention rate η. n =DCn / DC3×100%. When the capacity retention rate η... x When the percentage is 90%, record the number of cycles n at this point.

[0150] (3) Phase distribution of the electrolyte: Measurements were performed using laser confocal scanning microscopy (LCSM) or micro Raman mapping. Taking LCSM as an example, a static 2D grayscale image was obtained using an LCSM (Leica SP8, equipped with a 405 / 488 / 561 / 640 nm laser): 40× water mirror (NA 1.1), 488 nm excitation, emission acquisition range 500-550 nm, pinhole 1 Airy Unit, scanning format 1024×1024, pixel size 150 nm, single frame acquisition. 0.01wt% fluorescein was added to the electrolyte and injected into a sealed quartz cell with a thickness of 150μm. The cell was allowed to stand at room temperature for 30 min to equilibrate. The focal plane was adjusted to the center of the sample, and a single grayscale image was acquired. Raman mapping instrument conditions: laser wavelength 532nm or 633nm, spatial resolution ≤1μm, spectral range 200 cm⁻¹. -1 -2000cm -1 The electrolyte was dropped directly onto a glass slide and sealed with a coverslip to prevent evaporation. The instrument scan step size was set to 0.5 μm and the integration time per point to 3 s, and point-by-point spectral acquisition was performed on the target area. Multivariate analysis methods (such as MCR, PCA) or characteristic peak integration were used, combined with the characteristic peak positions of each solvent, to extract the contribution of each solvent component from the spectral data and generate a distribution map. The phase distribution maps obtained by both methods exhibited consistent characteristics.

[0151] The performance parameters of the electrolytes and lithium-ion batteries in each embodiment and comparative example are shown in Tables 3 and 4 below.

[0152] Table 3. Composition and content of electrolytes in various embodiments and comparative examples

[0153] Table 4 Performance parameters of electrolytes and lithium-ion batteries in each embodiment and comparative example

[0154] The test results of Example 1, Comparative Example 1, and Comparative Example 2 show that the electrolyte of the lithium-ion battery in Comparative Example 1 includes a first organic solvent and a phase stabilizer, but lacks a second organic solvent, resulting in poor cycle life at 45°C. The electrolyte of the lithium-ion battery in Comparative Example 2 includes a first organic solvent and a second organic solvent, but lacks a phase stabilizer. The cycle life of the lithium-ion battery at 45°C is improved compared to Comparative Example 1, but the improvement is small. This is because the phase stabilizer is an important component in constructing the bicontinuous emulsion gel (Bijel) phase electrolyte. The electrolyte in Example 1 includes a first organic solvent, a second organic solvent, and a phase stabilizer. This electrolyte exhibits certain immiscibility, providing the necessary conditions for preparing the bicontinuous emulsion gel phase. Furthermore, the weak solvation structure of the electrolyte allows for the achievement of good cycle life. In Example 1, the oligomers generated by the polymerization reaction of the aggregated phase stabilizer or a portion thereof can separate the two hydrophobic solvent systems (i.e., the first organic solvent and the second organic solvent), resulting in a macroscopically bicontinuous phase interface in the electrolyte. This unique phase distribution helps to weaken the solvation structure of lithium ions, suppress the reduction and oxidative decomposition reactions of the organic solvents (the first and second organic solvents) and lithium salts in the electrolyte, reduce the continuous consumption of the electrolyte during cycling, and alleviate the increase in interfacial impedance between the positive electrode 310 and the negative electrode 330, significantly extending the cycle life of the lithium-ion battery. Therefore, compared to Comparative Examples 1 and 2, the lithium-ion battery of Example 1 exhibits a significantly improved cycle life.

[0155] The test results of Example 1 and Comparative Example 3 show that the electrolytes of Example 1 and Comparative Example 3 have the same composition and content of each component. The difference lies in the preparation process of the electrolytes. The electrolyte of Comparative Example 3 was prepared using a conventional method, first mixing the first organic solvent and the second organic solvent, and then sequentially adding the lithium salt, film-forming additive, and phase stabilizer. The electrolyte of Comparative Example 3 was moderately turbid and partially gelled. The lithium-ion battery of Comparative Example 3 had a lower cycle life, which was lower than that of Comparative Example 1 (which did not contain the second organic solvent) and Comparative Example 2 (which did not contain the phase stabilizer). The turbidity of the electrolyte of Comparative Example 3 was also higher. This is because lithium salts and film-forming additives have strong redox properties in the electrolyte. The free radicals generated easily initiate the polymerization reaction of the phase stabilizer at room temperature. The high molecular weight polymers produced by the polymerization of insufficiently dispersed phase stabilizers encapsulate the lithium salt and electrolyte, causing a gel phenomenon. This results in only the liquid portion of the prepared electrolyte being usable, and this portion of the liquid electrolyte is missing a significant amount of lithium salt and film-forming additives. Therefore, the cycle performance of the lithium-ion battery deteriorates considerably. In Example 1, the lithium salt and film-forming additives are first dissolved in a first organic solvent, and the phase stabilizer is dissolved in a second organic solvent. Then, the solution containing the dissolved phase stabilizer is slowly added to the solution containing the lithium salt and film-forming additives to form the electrolyte. The phase stabilizer can be polymerized in a smaller and more appropriate amount. The low molecular weight polymers (phase stabilizer oligomers) and aggregates of phase stabilizer monomers coexist in the electrolyte without gelation and sedimentation. Its "self-assembly" characteristic helps the electrolyte to generate a bicontinuous phase interface. This stable electrolyte not only does not affect the film-forming additives' ability to form films, but also greatly improves the cycle life of lithium-ion batteries by regulating the solvation structure of lithium ions and slowing down the decomposition of the first organic solvent, the second organic solvent, and lithium salt.

[0156] The test results from Examples 1 to 5 and Comparative Examples 4 to 7 show that when the mass fraction w1 of the first organic solvent in the electrolyte is in the range of 60% ≤ w1 ≤ 85%; the mass fraction w2 of the second organic solvent in the electrolyte is in the range of 5% ≤ w2 ≤ 20%; and the mass fraction w3 of the phase stabilizer in the electrolyte is in the range of 0.05% ≤ w3 ≤ 5%, the lithium-ion battery has a high cycle life. Comparative Example 4 shows that when the mass fraction of the first organic solvent in the electrolyte is too low and the mass fraction of the second organic solvent is too high, the electrolyte becomes slightly turbid and partially gelled, reducing the cycle life of the lithium-ion battery. The test results from Comparative Example 5 show that when the mass fraction of the first organic solvent in the electrolyte is too high and the mass fraction of the second organic solvent is too low, the electrolyte becomes moderately turbid and opaque, significantly reducing the cycle life of the lithium-ion battery. Comparative Example 6 shows that when the mass fraction of the phase stabilizer in the electrolyte is too low, the cycle life of the lithium-ion battery decreases. As shown in Comparative Example 7, when the mass fraction of phase stabilizer in the electrolyte is too high, the electrolyte becomes heavily turbid and partially gelled, reducing the cycle life of the lithium-ion battery.

[0157] The test results from Examples 1, 6 to 18 show that using different types of first organic solvents, second organic solvents, and phase stabilizers can significantly improve the cycle life of lithium-ion batteries when the electrolyte forms a bicontinuous emulsion gel. Among these, the lithium-ion batteries of Examples 10, 13, 14, and 18 exhibit higher cycle lives compared to other examples. In particular, Example 18, using EC, EMC, DMC, and EA as the first organic solvent, HFE-578E as the second organic solvent, and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt as the phase stabilizer, can further improve the cycle life of the lithium-ion battery. Example 18 nearly doubled the number of cycles of the lithium-ion battery, demonstrating that the Bijel electrolyte of this application can significantly extend the cycle life of lithium-ion batteries without sacrificing kinetics.

[0158] As can be seen from the test results of Examples 1 to 18, the electrolyte of this application can greatly improve the cycle life of lithium-ion batteries, so that the number of cycles when the cycle capacity retention rate of lithium-ion batteries is 90% is greater than or equal to 470.

[0159] The test results of Examples 1 and Comparative Examples 8 to 10 show that the electrolytes in Comparative Examples 8 to 10 are all microemulsion electrolytes. When applied to lithium-ion batteries, the cycle life of the lithium-ion batteries is relatively low. This may be because the high-concentration lithium salt microemulsion electrolytes in Comparative Examples 8 and 9 have low conductivity and poor wetting, which cannot meet the normal lithium-ion transport requirements in lithium-ion batteries. This leads to abnormalities such as lithium plating and electrolyte bridging, and the capacity retention rate of the lithium-ion battery drops rapidly during cycling. In Comparative Example 10, the three-phase solvent system of the electrolyte has a narrow redox electrochemical stability window, and the film-forming ability of the additives is limited, resulting in a weak improvement in the cycle life of the lithium-ion battery.

[0160] Figure 9 The images show photographs and microstructures of the electrolyte in Example 1. Figure 9 In the image, 'a' represents the electrolyte. Figure 9 Images b and c in the image are laser confocal scanning microscope images of the electrolyte. Figure 10 A photograph of the electrolyte in Comparative Example 3. (Source: [Insert Source Here]) Figure 9 It can be seen that the electrolyte in Example 1 is slightly turbid and transparent, forming a bicontinuous emulsion-gel phase. From Figure 10 It can be seen that the electrolyte of Comparative Example 3 was moderately turbid and partially gelled, and did not form a bicontinuous emulsion-gel phase.

[0161] In this application, the terms "embodiment" and "implementation" mean that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of these phrases in various locations throughout the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this application can be combined with other embodiments. Furthermore, it should be understood that the features, structures, or characteristics described in the various embodiments of this application can be arbitrarily combined to form yet another embodiment that does not depart from the spirit and scope of the technical solution of this application, provided there is no contradiction between them.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. An electrolyte, characterized in that, The electrolyte comprises a first organic solvent, a second organic solvent, an electrolyte salt, and a phase stabilizer. The first organic solvent and the second organic solvent are interleaved to form their respective continuous network structures. The phase stabilizer is located at the phase interface between the first organic solvent and the second organic solvent. The hydrophobic parameter of the first organic solvent is smaller than that of the second organic solvent. The electrolyte salt is dissolved in both the first organic solvent and the second organic solvent.

2. The electrolyte according to claim 1, characterized in that, The hydrophobic parameter of the first organic solvent is LogP1, and the hydrophobic parameter of the second organic solvent is LogP2, then 0.3≤LogP2-LogP1≤5.

3. The electrolyte according to claim 1, characterized in that, The hydrophobic parameter LogP1 of the first organic solvent is in the range of -0.4≤LogP1≤2; And / or, The hydrophobic parameter LogP2 of the second organic solvent is in the range of 2≤LogP2≤5.

1.

4. The electrolyte according to claim 1, characterized in that, The mass ratio M of the first organic solvent to the second organic solvent in the electrolyte is in the range of 3 ≤ M ≤ 17.

5. The electrolyte according to claim 1, characterized in that, The mass fraction w1 of the first organic solvent in the electrolyte is in the range of 60% ≤ w1 ≤ 85%; And / or, The mass fraction w2 of the second organic solvent in the electrolyte is in the range of 5% ≤ w2 ≤ 20%.

6. The electrolyte according to claim 1, characterized in that, The mass fraction w3 of the phase stabilizer in the electrolyte is in the range of 0.05% ≤ w3 ≤ 5%.

7. The electrolyte according to any one of claims 1-6, characterized in that, The first organic solvent includes at least one of carbonate solvents and carboxylic acid ester solvents; The second organic solvent includes at least one of fluorocarbonate, fluorophosphate, fluoroether, and fluorophosphazene; The phase stabilizer includes at least one of alkenyl-containing sulfobetaine zwitterionic monomers and alkenyl-containing sodium sulfonate anionic monomers.

8. The electrolyte according to claim 7, characterized in that, The first organic solvent includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, methyl trifluoroethyl carbonate, 3,3,3-trifluoropropylene carbonate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, and ethyl 2,2-difluoroethyl acetate.

9. The electrolyte according to claim 7, characterized in that, The second organic solvent molecule contains 3 or more fluorine atoms.

10. The electrolyte according to claim 7, characterized in that, The second organic solvent includes bis(2,2,2-trifluoroethyl) carbonate, bis(2,2-difluoroethyl) carbonate, bis(2,2,2-trifluoroethyl) phosphite and tris(2,2,2-trifluoroethyl) phosphate, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 1,1,1,3, At least one of 3,3-hexafluoroisopropyl methyl ether, hexafluoropropyltrifluoroethyl ether, 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane, bis(2,2,2-trifluoroethyl) ether, 1,1,2,2-tetrafluoroethyl ethyl ether, tri(trifluoroethoxy)methane, tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane, hexafluorocyclotriphosphazene, pentafluoroethoxycyclotriphosphazene, and pentafluorophenoxycyclotriphosphazene.

11. The electrolyte according to claim 7, characterized in that, The phase stabilizer includes at least one of 1-(3-sulfonylpropyl)-2-vinylpyridinium inner salt, 1-(3-sulfonylpropyl)-4-vinylpyridinium inner salt, N,N-dimethyl-N-acrylamidopropyl-N-propanesulfonic acid inner salt, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 4-((2-(methacryloxy)ethyl)dimethylamino)butane-1-sulfonic acid inner salt, 3-[bis[2-(methacryloxy)ethyl](methyl)ammonium]propane-1-sulfonate, sodium allyl sulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, and sodium 2-(methacryloxy)ethyl sulfonate.

12. A single-cell battery, characterized in that, The single cell includes a positive electrode, a separator, a negative electrode, and an electrolyte as described in any one of claims 1-11, wherein the separator is disposed between the positive electrode and the negative electrode.

13. An energy storage device, characterized in that, The energy storage device includes one or more single-cell batteries as described in claim 12.

14. An electrical system, characterized in that, The power system includes: Electrical equipment; and The energy storage device of claim 13, wherein the energy storage device is used to supply power to the electrical equipment.

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