Electrolyte, secondary battery, and electric device

Abstract

The application discloses an electrolyte, a secondary battery and a power utilization device, and belongs to the technical field of new energy sources. The application adds a specific halogenated tertiary butyl ether diluent in the electrolyte, ensures that the electrolyte inherits the contact ion pair and ion aggregate solvation structure characteristics of high-concentration electrolyte, effectively reduces the viscosity of the electrolyte, improves the flame retardancy of the electrolyte, and induces the production of LiF and other halides of Li at the interface between the electrode and the electrolyte. The LiF can make the mechanical strength and compactness of the interface film higher, prevent the electrolyte and the electrode from continuously reacting, and inhibit the generation of lithium dendrites. The other halides of Li have a lower ion diffusion barrier, can promote the transmission behavior of lithium ions at the interface, and improve the rate performance of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, and relates to electrolyte, secondary battery and power utilization equipment. BACKGROUND

[0002] In recent years, researchers have found that increasing the concentration of lithium salt in electrolyte can effectively widen the voltage stability window of electrolyte, because when the concentration of lithium salt is high, the solvation structure of lithium ions in electrolyte will change, and lithium ions and anions in electrolyte are more likely to coordinate to form contact ion pairs (CIPs) and ion aggregates (AGGs). However, increasing the concentration of lithium salt in electrolyte not only makes electrolyte more viscous, affecting its performance in low-temperature environment and wettability with separators, but also brings about non-negligible raw material cost.

[0003] In order to solve the above problems existing in high-concentration electrolyte (HCEs), researchers have proposed local high-concentration electrolyte (LHCEs). At present, hydrofluoroether compounds are mainly used as diluents, but the ion conductivity of the electrode / electrolyte interface layer with LiF as the main component induced by the hydrofluoroether compounds is low, which is not conducive to the conduction of lithium ions at the interface, and further not conducive to the rate performance of the battery. Therefore, it is urgent to develop a technology to effectively solve the above problems existing in diluents. SUMMARY

[0004] Based on the above problems, the purpose of the present application is to provide an electrolyte, a secondary battery and a power utilization equipment, which aims to reduce the viscosity of electrolyte while inheriting the CIPs and AGGs solvation structure characteristics inherent in high-concentration electrolyte, improve the conduction of lithium ions at the interface between electrode and electrolyte, and improve the rate performance of the battery.

[0005] In order to achieve the above purpose, in a first aspect, the present application provides an electrolyte, comprising lithium salt, solvent, additive and diluent; the diluent comprises at least one of the compounds of formula I,

[0006]

[0007] In formula I, R 1 -R 10 each independently comprises a halogen element, R 1 -R 10 two or more halogen elements are present in R

[0008] In some embodiments, the molar percentage of F in the compound of formula I is 60%-90% based on the sum of the molar amounts of halogen elements in the compound of formula I.

[0009] In some embodiments, R1 -R 10 Cl, Br and I are present in the medium.

[0010] In some embodiments, the compound of formula I includes at least one of the following compounds:

[0011]

[0012] In some embodiments, the volume fraction of the compound of formula I in the electrolyte is 20%-80%.

[0013] In some embodiments, at least one of conditions (I)-(II) is satisfied:

[0014] (I) the solvent includes an ether solvent, and the ether solvent includes at least one of 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, dimethoxymethane and diglyme;

[0015] (II) the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide;

[0016] In some embodiments, the additive includes at least one of fluoroethylene carbonate, acrylonitrile, vinylene carbonate, 1,3-propanesultone, dimethylsulfone, trimethyl phosphate, 1,3,5-triformylphloroglucinol and tripropargyl phosphate.

[0017] In some embodiments, at least one of conditions (a)-(b) is satisfied:

[0018] (a) the molar concentration of the lithium salt in the electrolyte is 0.5-6.0 mol / L;

[0019] (b) the mass fraction of the additive in the electrolyte is 0.1%-5.0%.

[0020] In the second aspect of the present application, a secondary battery is provided, including a positive electrode sheet, a negative electrode sheet, a separator and the electrolyte of the first aspect.

[0021] In the third aspect of the present application, a power consumption device is provided, including the secondary battery of the second aspect, and the secondary battery serves as a power supply of the power consumption device.

[0022] The application has the beneficial effects that by adding the specific halogenated tertiary butyl ether diluent in the electrolyte, the electrolyte can not only inherit the contact ion pair and ion aggregate solvation structure characteristics of high concentration electrolyte, effectively reduce the viscosity of the electrolyte, but also improve the flame retardance of the electrolyte, induce the production of LiF and other halides of Li at the interface between the electrode and the electrolyte, wherein the LiF can make the mechanical strength and density of the interface film higher, prevent the continuous side reaction of the electrolyte and the electrode, and inhibit the generation of lithium dendrites; the other halides of Li have a lower ion diffusion barrier, which can promote the transmission behavior of lithium ions at the interface and improve the rate performance of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 Current density-voltage curve of the electrolyte of Example 1;

[0024] Fig. 2 Negative electrode surface photos of the electrolytes of Example 1 and Comparative Example 1 after 50 cycles. DETAILED DESCRIPTION

[0025] In order to better illustrate the purpose, technical scheme and advantages of the application, the application will be further described below in combination with specific examples and comparative examples, and the purpose is to understand the content of the application in detail, rather than limit the application. All other examples obtained by those of ordinary skill in the art without creative labor are within the protection scope of the application. The experimental reagents and instruments involved in the implementation of the application are common ordinary reagents and instruments unless otherwise specified. In the application, the open technical features described include closed technical solutions consisting of listed features, and also include open technical solutions containing listed features.

[0026] According to a first aspect of the application, an electrolyte is provided, which comprises a lithium salt, a solvent, an additive and a diluent, wherein the diluent comprises at least one of the compounds of formula I,

[0027]

[0028] In formula I, R 1 -R 10 each independently comprises a halogen element, R 1 -R 10 Two or more halogen elements are present in R

[0029] The addition of at least one compound of formula I as a diluent in the electrolyte can effectively reduce the viscosity of the electrolyte itself while ensuring that the electrolyte inherits the contact ion pair and ion aggregate solvation structure characteristics of high-concentration electrolytes, resulting in good low-temperature performance and good wettability with the separator. Moreover, the electrolyte's flame retardancy can be improved, and LiF and other halides of Li can be induced to form at the interface between the electrode and the electrolyte. LiF can make the interface film more mechanically strong and dense, preventing continuous side reactions between the electrolyte and the electrode and inhibiting the formation of lithium dendrites. Other halides of Li have a lower ion diffusion barrier, which can promote the transport of lithium ions at the interface and improve the rate performance of the battery.

[0030] In some embodiments, L comprises a C1alkylene, C2alkylene, C3alkylene, C4alkylene, C5alkylene, or C6alkylene. When L comprises a C2-C6alkylene, it can be either straight-chained or branched.

[0031] In some embodiments, the mole percentage of F in the compound of formula I is 60-90%, such as 60%, 70%, 80%, or 90%, based on the sum of the mole amounts of halogen elements in the compound, so that the cycle performance and rate performance balance of the battery are better.

[0032] In some embodiments, R 1 -R 10 contains two, three, four, or five halogen elements. In one embodiment, R 1 -R 10 contains at least one of Cl, Br, and I, for example, R 1 -R 10 contains Cl, or Br, or I, or Cl and Br, or Cl and I, or Br and I, or Cl, Br, and I.

[0033] In some embodiments, the compound of formula I includes at least one of the following compounds:

[0034] When the electrolyte contains at least one of 2-(chloromethoxy)-1,1,1,3,3-hexafluoro-2-(trifluoromethyl)propane (i.e., diluent A), 2-(bromomethoxy)-1,1,1,3,3-hexafluoro-2-(trifluoromethyl)propane (i.e., diluent B), and 2-(iodomethoxy)-1,1,1,3,3-hexafluoro-2-(trifluoromethyl)propane (i.e., diluent C), the cycle performance and rate performance of the battery are better.

[0035] In some embodiments, the volume fraction of the compound of formula I in the electrolyte is 20%-80%, such as 20%, 30%, 40%, 50%, 60%, 70%, or 80%, etc., so that the battery has better cycle performance.

[0036] The volume fraction of the compound of formula I in the electrolyte can be obtained by the following method:

[0037] The electrolyte and deuterated dimethyl sulfoxide (DMSO) are mixed and dispersed at a volume ratio of 1:4 to obtain a sample solution, which is tested by a nuclear magnetic resonance instrument. The compound of formula I is qualitatively determined by chemical shift, and the molar concentration of the compound of formula I in the sample solution is quantitatively determined by peak area, and then converted into volume fraction.

[0038] In some embodiments, the viscosity of the electrolyte at 25°C is 1.3-3 mPa·S, such as 1.3 mPa·S, 1.5 mPa·S, 2 mPa·S, 2.5 mPa·S, or 3 mPa·S, etc. Not only does the battery have good low-temperature performance, but also the electrolyte has good wettability with the separator.

[0039] The viscosity of the electrolyte can be obtained by the following method:

[0040] According to the standard GB / T 10247-2008, the viscosity of the electrolyte (16 mL) is measured by a rotary viscometer. A No. 0 rotor is used at a rotation speed of 50 rpm and a test temperature of 25°C.

[0041] In some embodiments, the decomposition voltage of the electrolyte is above 4.5V, such as 4.5V, 4.6V, 4.7V, or 4.8V, etc. These electrolytes can be adapted to high-voltage positive electrode materials such as ternary nickel-cobalt-manganese, ternary nickel-cobalt-aluminum, lithium iron phosphate, lithium manganese phosphate, etc., significantly improving the energy density of the battery. In the ternary nickel-cobalt-manganese, the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and manganese element is ≥0.8; and / or in the ternary nickel-cobalt-aluminum, the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and aluminum element is ≥0.8. Alternatively, in the ternary nickel-cobalt-manganese, the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and manganese element is in the range of 0.80, 0.85, 0.90, 0.95, 0.99, or any range formed by any two of the above values. Alternatively, in the ternary nickel-cobalt-aluminum, the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and aluminum element is in the range of 0.80, 0.85, 0.90, 0.95, 0.99, or any range formed by any two of the above values.

[0042] The decomposition voltage of the electrolyte can be obtained by the following method:

[0043] The linear sweep voltammetry (LSV) is used for testing. The metal lithium and the carbon-coated aluminum foil are used as the working electrode and the counter electrode respectively, 50 μL of the electrolyte is added to assemble a CR-2032 button cell, the electrochemical workstation is connected, the voltage range is set to 2.5-6.0 V, the scanning speed is set to 1 mV / s, and the decomposition voltage of the electrolyte is determined according to the initial position of the peak potential in the CV curve.

[0044] In some embodiments, the solvent in the electrolyte includes an ether solvent. As an example, the ether solvent includes at least one of 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2ME-THF), 1,3-dioxolane (DOL), dimethoxymethane (DMM), and diethylene glycol dimethyl ether (DG). The compound of formula I has good compatibility in the ether solvent, and is suitable for the electrolyte system with the addition of the ether solvent.

[0045] In some embodiments, the lithium salt in the electrolyte includes at least one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium bis(fluorosulfonyl)imide (LiFSI). When TFSI - and / or FSI - is contained in the electrolyte, the CIPs and AGGs can better promote the formation of stable SEI / CEI protective layers at the interface between the positive and negative electrodes and the electrolyte, avoid the generation of lithium dendrites, inhibit the oxidative decomposition of the electrolyte, and improve the cycle performance of the battery.

[0046] In some embodiments, the molar concentration of the lithium salt in the electrolyte is 0.5-6.0 mol / L, such as 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, or 6 mol / L, etc., so as to make the cycle performance of the battery better at a lower cost.

[0047] In some embodiments, the additive in the electrolyte includes at least one of fluoroethylene carbonate (FEC), acrylonitrile, vinylene carbonate (VC), 1,3-propanesultone (PS), dimethylsulfonylmethane (DMSM), trimethyl phosphate (TMP), 1,3,5-triformylphloroglucinol (TFP), and tripropargyl phosphate (TPP), so as to increase the compactness and ionic conductivity of the SEI layer on the surface of the lithium metal, and also improve the flame retardant performance and high and low temperature test stability of the electrolyte.

[0048] In some embodiments, the mass fraction of the additive in the electrolyte is 0.1%-5.0%, such as 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, or 5.0%, etc., so as to improve the cycle performance, rate performance, etc. of the battery at a lower cost.

[0049] According to a second aspect of the present application, a secondary battery is provided, comprising a positive electrode sheet, a negative electrode sheet, a separator, and the above-mentioned electrolyte.

[0050] In some embodiments, the negative electrode sheet comprises a negative electrode active material. As an example, the negative electrode active material comprises at least one of lithium metal, carbon-based material, silicon-based material, and metal oxide material. Among them, lithium metal has extremely low electrochemical potential (-3.04 V vs. hydrogen standard electrode) and ultra-high theoretical specific capacity (about 3860 mAh / g), and is one of the ideal negative electrode active materials for the next generation of high-energy-density battery systems. The lithium metal negative electrode has strong electrochemical activity, and the commercial carbonate-based electrolyte will have serious side reactions with it, generating an unstable solid-state interfacial electrolyte film (SEI) on the lithium metal negative electrode side. During subsequent electrochemical cycling, the SEI film will undergo continuous changes in dissolution-reformation, constantly consuming lithium salts in the electrolyte, causing capacity attenuation. The side reaction of ether-based solvents with lithium metal negative electrode is weaker, and is more suitable for lithium metal negative electrode system batteries. Optionally, the ether-based solvent comprises at least one of 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2ME-THF), 1,3-dioxolane (DOL), dimethoxymethane (DMM), and diethylene glycol dimethyl ether (DG). The volume ratio of the compound of formula I and the ether-based solvent can be selected as (0.1-9):1, such as 0.1:1, 0.2:1, 0.5:1, 0.7:1, 1:1, 3:1, 5:1, 7:1, or 9:1, etc.

[0051] In some embodiments, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer disposed on at least one side of the positive electrode current collector, wherein the positive electrode active layer comprises a positive electrode active material. As an example, the positive electrode active material comprises at least one of lithium cobaltate, ternary nickel-cobalt-manganese, ternary nickel-cobalt-aluminum, lithium iron phosphate, and lithium manganese phosphate.

[0052] In an embodiment, the positive electrode active material comprises at least one of ternary nickel-cobalt-manganese, ternary nickel-cobalt-aluminum, lithium iron phosphate, and lithium manganese phosphate, wherein the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and manganese element in ternary nickel-cobalt-manganese ≥ 0.8; and / or the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and aluminum element in ternary nickel-cobalt-aluminum ≥ 0.8, so as to make the energy density of the battery higher. Optionally, the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and manganese element in ternary nickel-cobalt-manganese is 0.80, 0.85, 0.90, 0.95, 0.99, or a range formed by any two of the above numbers. Optionally, the molar amount of nickel element / the sum of molar amounts of nickel element, cobalt element, and aluminum element in ternary nickel-cobalt-aluminum is 0.80, 0.85, 0.90, 0.95, 0.99, or a range formed by any two of the above numbers.

[0053] In some embodiments, the mass fraction of the positive active material in the positive active layer is 70-90%, such as 70%, 75%, 80%, 85%, 90%, or a range formed by any two of the above values.

[0054] In some embodiments, the positive active layer further comprises a conductive agent. As an example, the conductive agent comprises at least one of conductive carbon black and super conductive carbon black (acetylene black, Super P, etc.).

[0055] In some embodiments, the mass fraction of the conductive agent in the positive active layer is 3-15%, such as 3%, 5%, 10%, 15%, or a range formed by any two of the above values.

[0056] In some embodiments, the positive active layer further comprises a binder. As an example, the binder comprises at least one of oily binder polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), and carboxymethyl cellulose (CMC).

[0057] In some embodiments, the mass fraction of the binder in the positive active layer is 3-15%, such as 3%, 5%, 10%, 15%, or a range formed by any two of the above values.

[0058] In some embodiments, the material of the separator comprises at least one of polypropylene and polyethylene.

[0059] In some embodiments, the secondary battery forms, during the first charging process, an SEI film on the surface of the negative electrode, the film having a thickness of 3-200 nm, the film containing LiF and at least one of other halides of Li. In one of the embodiments, the SEI film contains LiF and LiCl, or LiF and LiBr, or LiF and LiI, or LiF, LiCl, and LiBr, or LiF, LiCl, and LiI, or LiF, LiBr, and LiI, or LiF, LiCl, LiBr, and LiI. The thickness of the SEI film is related to the amount of the compound of Formula I added, and generally the higher the amount of the compound of Formula I added, the thicker the SEI film.

[0060] According to a third aspect of the present application, a power consuming device is provided, which comprises the above secondary battery as its power supply. As an example, the power consuming device comprises at least one of a digital product, an energy storage power station, and an electric vehicle.

[0061] Embodiment 1

[0062] The present embodiment provides an electrolyte, and a preparation method thereof comprises the following steps:

[0063] The solvent 1,2-dimethoxyethane (DME) and the diluent 2-(bromomethoxy)-1,1,1,3,3-hexafluoro-2-(trifluoromethyl)propane (diluent B) were mixed and dispersed in a volume ratio of 2:1, then the lithium salt lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) was added and dispersed, then the additive fluoroethylene carbonate (FEC) was added and dispersed, to obtain the electrolyte.

[0064] In the electrolyte, the volume fraction of the diluent is 66.7%, the molar concentration of the lithium salt is 1 mol / L, and the mass fraction of the additive is 0.1%.

[0065] Examples 2-17

[0066] These examples all provide an electrolyte, and the differences between these electrolytes and Example 1 are shown in Table 1.

[0067] Comparative Example 1

[0068] This comparative example provides an electrolyte, and the difference between this electrolyte and Example 1 is that no diluent is added, and the mass fraction of the additive is 0.5%.

[0069] Comparative Example 2

[0070] This comparative example provides an electrolyte, and the difference between this electrolyte and Example 1 is that the diluent is hydrofluoroether (HFE, CAS: 406-78-0).

[0071] Table 1

[0072]

[0073] The electrolytes obtained in each example and comparative example were subjected to the following performance tests:

[0074] Viscosity test: The prepared electrolyte (16 mL) was subjected to viscosity measurement using a rotary viscometer. A No. 0 rotor was used at a rotation speed of 50 rpm, and the test temperature was 25°C;

[0075] Decomposition voltage test: A CR-2032 button cell was assembled by adding 50 μL of the prepared electrolyte, using lithium metal and carbon-coated aluminum foil as the working electrode and the counter electrode, respectively, connecting an electrochemical workstation, setting the voltage range to 2.5-6.0 V, and setting the scan speed to 1 mV / s. The decomposition voltage of the electrolyte was determined according to the starting position of the peak potential in the CV curve.

[0076] Rate performance test: The electrolyte was assembled into a battery with a positive electrode sheet, a negative electrode sheet, and a separator. The negative electrode sheet was a lithium metal sheet. The positive electrode sheet was prepared by the following method: the positive electrode active material (LiNi 0.8 Co 0.1 Mn0.1 O2), Super P and PVDF were mixed and ground in a mass ratio of 8:1:1, then a certain amount of NMP was added to the mixture, and the grinding and dispersion were continued, then the obtained slurry was coated on a copper foil with a scraper, and after vacuum drying at 80℃ for 12h, it was cut into 13mm round pieces with a punch machine; the separator was a polypropylene film. The assembled battery was charged at 0.5C constant current and constant voltage to 4.3V, and then discharged at 0.5C, 1C, 1.5C and 2C rates to 2.8V, respectively, and the capacity change of the battery was recorded;

[0077] Cycle performance test: the electrolyte was assembled into a battery according to the method in the rate performance test, and the obtained battery was charged and discharged at 0.2C rate in the voltage range of 4.3-2.8V, and the cycle number when the capacity decayed to 80% of the initial capacity was recorded.

[0078] Some test results are shown in Figs. 1-2 and Table 2.

[0079] Table 2

[0080]

[0081]

[0082] As can be seen from Table 1, the electrolyte of each embodiment of the present application has low viscosity, high decomposition voltage, excellent cycle performance and rate performance, such as viscosity of 1.3-3mPa·S at 25℃, decomposition voltage above 4.5V, cycle number above 240 when the capacity decayed to 80% of the initial capacity, 0.5C discharge capacity above 180mAh·g -1 1C discharge capacity above 170mAh·g -1 1.5C discharge capacity above 160mAh·g -1 2C discharge capacity above 145mAh·g -1 .

[0083] As can be seen from the comparison of each embodiment with Comparative Example 1, by adding the compound of formula I to the electrolyte, not only can the decomposition voltage of the electrolyte be improved, but also the cycle life of the battery can be significantly improved.

[0084] As can be seen from the comparison of each embodiment with Comparative Example 1, compared with adding a conventional hydrofluoroether diluent, adding the compound of formula I can make the cycle performance and rate performance of the battery better.

[0085] As can be seen from the comparison of Examples 1 and 7-10, when the volume fraction of the compound of formula I in the electrolyte is in the range of 20%-80%, the decomposition voltage of the electrolyte is higher, and the cycle performance and rate performance are better.

[0086] In addition, Fig. 1The electrolyte of Example 1 has a high decomposition voltage; Fig. 2 It is shown that, compared with Comparative Example 1, Example 1 can effectively inhibit the generation of lithium metal negative electrode lithium dendrites due to the addition of a specific diluent.

[0087] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. An electrolyte, characterized in that, It comprises a lithium salt, a solvent, an additive, and a diluent; the diluent comprises at least one compound of formula I. Formula I; In Equation I, R 1 -R 10 Each contains halogen elements independently, R 1 -R 10 The presence of two or more halogens, with at least one of them containing F; L contains C1-C6 alkylene groups; The compound with the structure shown in Formula I includes at least one of the following structures: ； The compound with the structure shown in Formula I has a volume fraction of 20%-80% in the electrolyte.

2. The electrolyte as described in claim 1, characterized in that, At least one of conditions (I)-(II) must be satisfied: (I) The solvent includes ether solvents, which include at least one of 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, dimethoxymethane and diethylene glycol dimethyl ether; (II) The lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide.

3. The electrolyte as described in claim 1, characterized in that, The additives include at least one of fluoroethylene carbonate, acrylonitrile, vinylene carbonate, 1,3-propanesulfonyl lactone, dimethylsulfonylmethane, trimethyl phosphate, 1,3,5-trialdehyde phloroglucinol, and tripropynyl phosphate.

4. The electrolyte as described in claim 1, characterized in that, At least one of conditions (a)-(b) must be satisfied: (a) The molar concentration of the lithium salt in the electrolyte is 0.5-6.0 mol / L; (b) The mass fraction of the additive in the electrolyte is 0.1%-5.0%.

5. A secondary battery, characterized in that, It includes a positive electrode, a negative electrode, a separator, and an electrolyte as described in any one of claims 1-4.

6. An electrical appliance, characterized in that, Includes the secondary battery as described in claim 5, wherein the secondary battery serves as the power supply for the electrical equipment.

Images