Electrolyte, battery and electric device

Abstract

The embodiment of the invention provides an electrolyte, a battery and a power utilization device, the electrolyte comprises a lithium salt, a first additive and a second additive, the lithium salt comprises lithium hexafluorophosphate, the second additive is lithium fluorosulfonate, and the first additive has a structure as shown in a formula (1). The first additive and the second additive have a synergistic effect, an organic-inorganic composite CEI film is formed on the positive electrode, meanwhile, an inorganic SEI film with high ionic conductivity is formed on the negative electrode, and the CEI film and the SEI film can reduce side reactions between the electrode and an electrolyte, so that damage to the surface structure of the electrode and decomposition gas production of the electrolyte are reduced, and the service life of the electrolyte is prolonged. The cycle performance of the battery is improved; and the inorganic SEI film with high ionic conductivity can improve the transmission rate of conductive ions, so that the power performance of the battery is improved, and the battery has relatively good cycle performance and power performance.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to an electrolyte, a battery, and an electrical device. Background Art

[0002] In recent years, with the transformation of the global energy structure and the advancement of the "dual carbon" goals, secondary batteries such as lithium-ion batteries and sodium-ion batteries have become core technologies in the fields of energy storage and mobile energy due to their cyclic charging and discharging characteristics.

[0003] However, in related technologies, the battery electrolyte is prone to side reactions with the electrodes during multiple charge and discharge cycles, causing the electrode surface structure to be gradually damaged, which in turn leads to rapid decay of the battery capacity and deterioration of the battery's cycle performance; at the same time, the ionic conductivity of traditional electrolytes is limited, and ions cannot be transported quickly during battery charging and discharging, reducing the battery's power performance; the battery cannot have both good cycle performance and power performance, and needs further improvement. Summary of the Invention

[0004] The embodiments of the present application provide an electrolyte, a battery, and an electrical device, which aim to solve the aforementioned technical problems at least to a certain extent.

[0005] In a first aspect, an embodiment of the present application provides an electrolyte, comprising a lithium salt, a first additive, and a second additive, wherein the lithium salt comprises lithium hexafluorophosphate, the second additive is lithium fluorosulfonate, and the structure of the first additive is shown in the following formula (1): Formula (1).

[0006] In one embodiment, the mass ratio of the first additive to the second additive is (0.5-8):1.

[0007] In one embodiment, the mass percentage of the first additive in the electrolyte is 0.05%-2%; and / or The mass percentage of the second additive in the electrolyte is 0.05%-2%.

[0008] In one embodiment, the mass percentage of the first additive in the electrolyte is 0.1%-1.5%; and / or The mass percentage of the second additive in the electrolyte is 0.1%-1%.

[0009] In one embodiment, the electrolyte further includes a lithium salt and / or a solvent.

[0010] In one embodiment, the mass percentage of the lithium salt in the electrolyte is 10%-15%.

[0011] In one embodiment, the solvent includes at least one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, ethylene carbonate, ethyl acetate, propyl acetate, methyl propionate, methyl acetate, ethyl propionate, propyl propionate, ethyl butyrate, methylpropyl carbonate, γ-butyrolactone and γ-valerolactone.

[0012] In a second aspect, an embodiment of the present application further provides a battery comprising the electrolyte as described above.

[0013] Beneficial effects of the embodiments of the present application: The embodiment of the present application provides an electrolyte, which includes a lithium salt, a first additive, and a second additive. The lithium salt includes lithium hexafluorophosphate, the second additive is lithium fluorosulfonate, and the first additive has a structure as shown in formula (1). The first additive preferentially undergoes an electrochemical oxidation reaction at the positive electrode due to its high oxidation potential. The benzene ring structure of the first additive undergoes oxidative dehydrogenation polymerization to form phenyl derivatives such as polyaniline, thereby constructing a composite cathode electrolyte interface film (CEI film) containing inorganic substances and phenyl derivatives. The phenyl derivatives significantly improve the flexibility and mechanical strength of the CEI film, maintain the lattice stability of the positive electrode active material through mechanical support, reduce electrolyte contact and inhibit high-temperature gas production; the organic reinforced CEI film effectively compensates for the positive electrode film formation defects (poor flexibility and weak mechanical support) caused by the insufficient oxidation stability of lithium fluorosulfonate. At the same time, the first additive has a tendency to reduce and decompose at the negative electrode, and the sulfur / fluorine species of the first additive (such as FSI - LiPF6 (lithium hexafluorophosphate) derivatives generate high-impedance inorganic substances such as Li2S (lithium sulfide) and Li3N (lithium nitride) under the catalysis of LiPF6 (lithium hexafluorophosphate) hydrolysis products, which may destroy the uniformity of the solid electrolyte interface film (SEI film) and deteriorate ion conduction. The sulfonate radical (-SO3 - ) It reduces the desolvation energy barrier of lithium ions through strong coordination competition, and its low reduction potential takes precedence over LiPF6 and the decomposition products of the first additive in reduction at the negative electrode, quickly forming a dense inorganic SEI film skeleton with high ionic conductivity mainly composed of lithium sulfite and lithium fluoride; this process inhibits the reduction and decomposition of the first additive through electron competition, and uses the dense SEI physical barrier to reduce the doping of the decomposition products of the first additive.

[0014] The first and second additives synergistically achieve bidirectional defect compensation: the first additive overcomes the shortcomings of lithium fluorosulfonate in cathode protection, while lithium fluorosulfonate reduces the risk of negative electrode damage from the first additive. The CEI and SEI membranes synergistically inhibit electrode-electrolyte side reactions and structural damage, significantly improving cycle performance. The highly conductive SEI membrane at the negative electrode accelerates ion transport and enhances power performance, ultimately achieving synergistic optimization of cycle and power performance. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state; while "inside" and "outside" refer to the outline of the device.

[0016] In related technologies, batteries cannot have both good cycle performance and power performance, and need further improvement.

[0017] The present invention provides an electrolyte solution, which includes a lithium salt, a first additive, and a second additive. The lithium salt includes lithium hexafluorophosphate, the second additive is lithium fluorosulfonate, and the structure of the first additive is shown in the following formula (1): Formula (1).

[0018] In this embodiment, the electrolyte includes a first additive and a second additive, the second additive has a sulfonate ion, and the first additive has a structure as shown in formula (1). The first additive preferentially undergoes an electrochemical oxidation reaction at the positive electrode due to its high oxidation potential. The benzene ring structure of the first additive undergoes oxidative dehydrogenation polymerization to form phenyl derivatives such as polyaniline, thereby constructing a composite cathode electrolyte interface film (CEI film) containing inorganic substances and phenyl derivatives. The phenyl derivatives significantly improve the flexibility and mechanical strength of the CEI film, maintain the lattice stability of the positive electrode active material through mechanical support, reduce electrolyte contact and inhibit high-temperature gas production; the organic reinforced CEI film effectively compensates for the positive electrode film formation defects (poor flexibility and weak mechanical support) caused by the insufficient oxidation stability of lithium fluorosulfonate. At the same time, the first additive has a tendency to reduce and decompose at the negative electrode, and the sulfur / fluorine species of the first additive (such as FSI) - LiPF6 (lithium hexafluorophosphate) derivatives generate high-impedance inorganic substances such as Li2S (lithium sulfide) and Li3N (lithium nitride) under the catalysis of LiPF6 (lithium hexafluorophosphate) hydrolysis products, which may destroy the uniformity of the solid electrolyte interface film (SEI film) and deteriorate ion conduction. The sulfonate radical (-SO3 - ) It reduces the desolvation energy barrier of lithium ions through strong coordination competition, and its low reduction potential takes precedence over LiPF6 and the decomposition products of the first additive in reduction at the negative electrode, quickly forming a dense inorganic SEI film skeleton with high ionic conductivity mainly composed of lithium sulfite and lithium fluoride; this process inhibits the reduction and decomposition of the first additive through electron competition, and uses the dense SEI physical barrier to reduce the doping of the decomposition products of the first additive.

[0019] The first and second additives synergistically achieve bidirectional defect compensation: the first additive overcomes the shortcomings of lithium fluorosulfonate in cathode protection, while lithium fluorosulfonate reduces the risk of negative electrode damage from the first additive. The CEI and SEI membranes synergistically inhibit electrode-electrolyte side reactions and structural damage, significantly improving cycle performance. The highly conductive SEI membrane at the negative electrode accelerates ion transport and enhances power performance, ultimately achieving synergistic optimization of cycle and power performance.

[0020] In one embodiment, the mass ratio of the first additive to the second additive is (0.5-8): 1. Alternatively, the mass ratio of the first additive to the second additive may be any one of 0.5:1, 1:1, 3:1, 5:1, 7:1, 8:1, etc., or a range between any two thereof, which is not limited herein.

[0021] In this embodiment, when the mass ratio of the first additive to the second additive is less than 0.5:1, it is easy to cause the content of the first additive to be too little and the content of the second additive to be too much, resulting in insufficient content of phenyl derivatives such as polyaniline in the positive electrode CEI membrane, reduced density of the CEI membrane, and the CEI membrane presenting a porous structure (the porosity of the CEI membrane is greater than 40%). The anions in the electrolyte can easily penetrate the pores of the CEI membrane and embed into the positive electrode lattice, triggering a layered structure phase transition, thereby reducing the diffusion coefficient of the conductive ions (the diffusion coefficient of the conductive ions is reduced to 10 -12 cm 2 / s) and transmission rate; at the same time, the excess second additive competes for electrons at the positive electrode interface, and the SO3 generated by the oxidation of the second additive 2- Free radicals can catalyze the decomposition of solvents, increase battery gas production (battery gas production increases by 2 times), and accelerate the dissolution of transition metals. The dissolved ions can migrate to the negative electrode to catalyze the decomposition of the SEI film, causing battery expansion (battery expansion rate exceeds 5%). When the mass ratio of the first additive to the second additive is greater than 8:1, it is easy to cause the content of the first additive to be too much and the content of the second additive to be too little. The effect of the second additive in inhibiting the reduction reaction of the first additive at the negative electrode is not ideal. A large amount of the first additive undergoes a reduction reaction in the negative electrode region to generate phenyl derivatives that easily form cross-linked polymers (molecular weight of the cross-linked polymer>5000Da), blocking the conductive ion transmission channel (the pore size of the transmission channel<1nm), and increasing the interface impedance of the SEI film (interface impedance from 20Ω·cm 2 Increased to 100Ω·cm 2At the same time, the content of inorganic components such as sulfur oxides and lithium fluoride in the SEI film decreases (the mass percentage of lithium fluoride in the SEI film drops below 30%), which can easily lead to accelerated growth of lithium dendrites (lithium dendrite length increases to 10μm). The electron tunneling effect triggers continuous reduction and gas production of the electrolyte (gas production rate 0.3mL / Ah / cycle), causing battery expansion (battery thickness expansion rate exceeds 8%). Therefore, setting the mass ratio of the first additive to the second additive to (0.5-8):1 can further ensure the battery has good cycle performance and power performance.

[0022] In this embodiment, when the mass ratio of the first additive to the second additive is set at (0.5-8):1, the mass percentage of lithium fluoride in the positive electrode CEI membrane is 30%-50%, and the mass percentage of polyaniline is 50%-70%. In the negative electrode SEI membrane, the mass percentage of lithium fluoride is 70%-90%, and the mass percentage of lithium sulfite is 10%-30%. Lithium fluoride and lithium sulfite improve the conductivity and reduce the interfacial impedance of the SEI membrane, while polyaniline improves the flexibility and mechanical strength of the CEI membrane, reduces contact between the electrolyte and the electrode material, and inhibits electrolyte decomposition and gas production under high-temperature conditions. The first and second additives synergistically achieve dynamic equilibrium in the interfacial membrane, ensuring excellent battery cycling and power performance. After 1000 cycles at a high voltage of 4.4V, the battery exhibits a capacity retention rate of >85%, gas production of <0.05mL / Ah, and a stable interfacial impedance of 20Ω·cm. 2 Within.

[0023] X-ray photoelectron spectroscopy can be used to analyze the content of lithium sulfite, lithium fluoride, and polyaniline in the CEI and SEI films. The analysis depth is approximately 5nm-10nm, and the content of components such as lithium sulfite, lithium fluoride, and polyaniline in the interface film can be determined by peak fitting.

[0024] In one embodiment, the mass percentage of the first additive in the electrolyte is 0.05%-2%. Alternatively, the mass percentage of the first additive in the electrolyte can be any one of 0.05%, 0.1%, 0.5%, 1%, 1.3%, 1.6%, 2%, or any range between two thereof, without limitation herein. Preferably, the mass percentage of the first additive in the electrolyte is 0.1%-1.5%.

[0025] In this embodiment, the mass percentage of the first additive in the electrolyte is set to 0.05%-2%, which can ensure that the first additive can better form a high ionic conductivity inorganic SEI film skeleton at the negative electrode and inhibit the side reaction of the second additive at the negative electrode; at the same time, the oxidation of the second additive to generate SO3 2-Free radicals, thereby reducing the side reactions of the second additive in the battery.

[0026] In one embodiment, the mass percentage of the second additive in the electrolyte is 0.05%-2%. Alternatively, the mass percentage of the second additive in the electrolyte can be any one of 0.05%, 0.1%, 0.5%, 1%, 1.3%, 1.6%, 2%, or any range between two thereof, without limitation herein. Preferably, the mass percentage of the second additive in the electrolyte is 0.1%-1%.

[0027] In this embodiment, the mass percentage of the second additive in the electrolyte is set to 0.05%-2%, which can ensure that the second additive can form a dense CEI film containing phenyl derivatives such as polyaniline at the positive electrode, reducing the contact between the electrolyte and the electrode material; at the same time, it reduces the reduction reaction of the first additive in the negative electrode region to generate phenyl derivatives, thereby reducing the blockage of the conductive ion transmission channel of the SEI membrane by the cross-linked polymer formed between the phenyl derivatives, ensuring that the SEI membrane has a lower interface impedance.

[0028] In one embodiment, the first additive and the second additive can be purchased directly or prepared by themselves. Specifically, the first additive is N-phenylbis(fluorosulfonyl)imide. N-phenylbis(fluorosulfonyl)imide (CAS No.: 1622206-83-0) and lithium fluorosulfonate can be purchased directly.

[0029] In one embodiment, the electrolyte further includes a lithium salt, and the mass percentage of the lithium salt in the electrolyte is 10%-15%. Alternatively, the mass percentage of the lithium salt in the electrolyte can be any one of 10%, 11%, 12%, 13%, 14%, 15%, or any range between two thereof, without limitation herein. In this embodiment, setting the mass percentage of the lithium salt in the electrolyte within the above range can result in the electrolyte having good ionic conductivity.

[0030] In one embodiment, the electrolyte further includes a solvent, and the solvent includes at least one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, ethylene carbonate, ethyl acetate, propyl acetate, methyl propionate, methyl acetate, ethyl propionate, propyl propionate, ethyl butyrate, methylpropyl carbonate, γ-butyrolactone, and γ-valerolactone.

[0031] The present application also provides a battery, comprising the electrolyte as described above. In this embodiment, the battery may comprise a lithium-ion battery or a sodium-ion battery, and the type of battery is not limited here.

[0032] The present application also provides an electrical device, including the electrolyte described above, or including the battery described above. In this embodiment, the type of the electrical device is not limited, and the electrical device can be a car, a ship, an unmanned aerial vehicle, a fixed power source, a portable power source, etc.

[0033] The above scheme is further described below with reference to specific implementation examples. The embodiments of this application are described in detail as follows: Example 1 1. Preparation of electrolyte In an argon atmosphere glove box (water content <1 ppm, oxygen content <1 ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) were mixed uniformly in a mass ratio of 30:40:30 to obtain a solvent, and lithium hexafluorophosphate (LiPF6), a first additive, and a second additive were added to the solvent, dissolved, and mixed uniformly to obtain an electrolyte; wherein: The mass percentage of lithium hexafluorophosphate (LiPF6) in the electrolyte is 12.5%; The mass percentage of the first additive in the electrolyte is 1%; The second additive is lithium fluorosulfonate, and the mass percentage of the second additive in the electrolyte is 0.5%; The rest is solvent.

[0034] 2. Preparation of positive electrode sheet Lithium iron phosphate, conductive agent CNT (conductive carbon nanotube), conductive agent SP (conductive carbon black) and binder PVDF (polyvinylidene fluoride) are uniformly dispersed in NMP (N-methylpyrrolidone) solvent at a mass ratio of 96:0.5:1.0:2.5. After stirring for a period of time under a vacuum environment, a positive electrode slurry with a solid content of 60% is obtained. The positive electrode slurry is evenly coated on both surfaces of the aluminum foil, the electrode is dried, and the pressure is adjusted to 2.45g / cm 3 The density is compacted and rolled, and finally die-cut into the specified size to obtain the positive electrode sheet.

[0035] 3. Preparation of negative electrode sheet Graphite, SP (conductive carbon black), binder CMC (carboxymethyl cellulose) and binder SBR (styrene-butadiene rubber emulsion) are uniformly dispersed in deionized water at a mass ratio of 96.0:1.0:1.0:2.0. After being fully stirred under vacuum, a negative electrode slurry with a solid content of 60% is obtained. The negative electrode slurry is evenly coated on both surfaces of the copper foil, the electrode is dried, and the surface is heated to 1.6 g / cm 3 The density is compacted and rolled, and finally die-cut into the specified size to obtain the negative electrode sheet. 4. Preparation of lithium-ion batteries The positive electrode sheet, polyethylene separator, and negative electrode sheet prepared above were stacked in order, with the separator positioned between the positive and negative electrode sheets to act as a separator. The stacked battery was assembled, with the positive tab connected to the positive electrode sheet and the negative tab connected to the negative electrode sheet, to obtain an electrode assembly. The electrode assembly was placed in an aluminum foil bag, and the positive and negative tabs were led out of the inner space of the aluminum foil bag to the outer space of the aluminum foil bag. The bag was vacuum-dried at 85°C for 48 hours, and the electrolyte prepared above was injected at an injection rate of 3.0 g / Ah. The battery was vacuum-sealed, formed, aged, and then capacitated to obtain a lithium-ion battery. The upper limit voltage for formation was 3.9 V, the formation temperature was 45°C, and the formation rest time was 2 hours; the aging temperature was 45°C, and the aging rest time was 24 hours; the capacitated battery was charged at 0.1C to 4.35 V, left for 5 minutes, and then discharged at 0.1C to 3.0 V. The above steps were then repeated three times to obtain a lithium-ion battery.

[0036] The preparation methods of the lithium ion batteries of Examples 2-25 and Comparative Examples 1-4 are the same as that of Example 1, except that the electrolyte compositions are different, as shown in Table 1.

[0037] Table 1

[0038] Test Method The electrochemical performance of the lithium-ion batteries prepared in Examples 1 to 25 and Comparative Examples 1 to 4 was tested as follows: (1) High temperature cycle performance test: At 45°C, the lithium-ion battery is charged and discharged 1500 times at a current of 1C. The capacity retention rate (%) = (1500th discharge capacity / 1st discharge capacity) × 100%.

[0039] (2) Low temperature discharge performance test method: Place a lithium-ion battery with capacity separation in a 25°C environment and charge it at a constant current and voltage of 1C to the upper cutoff voltage, with a cutoff current of 0.05C. Then discharge it at a constant current of 1C to the lower cutoff voltage. Record the discharge capacity at room temperature at this time as C1. Then charge the battery again at a constant current and voltage of 1C to the upper cutoff voltage, with a cutoff current of 0.05C. Place the fully charged battery in a low-temperature constant temperature box at -20±2°C for 5 hours, and then discharge it at a constant current of 0.5C to the lower cutoff voltage. Record the discharge capacity at this time as C2. Capacity retention rate = (C2 / C1)×100%.

[0040] (3) Capacity retention rate after 30 days of high-temperature storage The 1C discharge capacity of the lithium-ion battery is recorded as C0. The battery is then placed in a 60°C oven for storage for 30 days. After the storage time is over, the lithium-ion battery is taken out and cooled to room temperature. At 25°C, it is discharged at a constant current of 1C to 2V, and the discharge capacity is recorded as C1. The high-temperature storage capacity retention rate is calculated as follows: High-temperature storage capacity retention rate (%) = (discharge capacity C1 in the first cycle after storage / 1C discharge capacity C0) × 100%.

[0041] The test results are shown in Table 2 below: Table 2

[0042] As can be seen from the test results in Table 2, compared with Comparative Examples 1 to 4, the lithium-ion batteries prepared in Examples 1 to 25 have improved capacity retention rates for 30 days of high-temperature storage, 1500 cycles of high-temperature cycling at 45°C, and low-temperature discharge. This indicates that by adding a first additive and a second additive to the electrolyte, the second additive is lithium fluorosulfonate, and the first additive has a structure as shown in Formula (1). The first additive can preferentially undergo electrochemical oxidation reactions at the positive electrode to form a cathode electrolyte interface film (CEI film) containing inorganic substances and phenyl derivatives such as polyaniline, reducing the contact between the electrolyte and the electrode material and inhibiting the decomposition and gas production of the electrolyte under high-temperature conditions. The second additive can quickly occupy the active sites of the negative electrode and preferentially form a high-ionic conductivity inorganic SEI film skeleton composed mainly of sulfur oxides such as lithium sulfite and lithium fluoride on the negative electrode surface, reducing the side reactions between the first additive and the negative electrode. At the same time, the second additive inhibits the reduction reaction of the first additive through electron competition, reducing the impact of the decomposition products of the first additive on the conductivity of the SEI film. The first additive and the second additive work synergistically to form an organic-inorganic composite CEI film at the positive electrode, and at the same time, an inorganic SEI film with high ionic conductivity is formed at the negative electrode. The CEI film and SEI film can reduce the side reactions between the electrode and the electrolyte, thereby reducing the damage to the electrode surface structure and the decomposition and gas production of the electrolyte, and improving the cycle performance of the battery; and the inorganic SEI film with high ionic conductivity can increase the transmission rate of conductive ions, thereby improving the power performance of the battery, so that the battery can have both good cycle performance and power performance.

[0043] From the comparison between Examples 1-16 and Examples 17-25, it can be seen that setting the mass ratio of the first additive to the second additive to (0.5-8):1 can ensure that the battery has better cycle performance and power performance.

[0044] From the comparison of Examples 1-12, Examples 15-16, Example 23, and Example 25, it can be seen that controlling the mass percentage of the first additive in the electrolyte within the range of 0.05%-2% can ensure that the battery has good cycle performance.

[0045] From the comparison of Examples 1-12, 13-14, and 24-25, it can be seen that controlling the mass percentage of the second additive in the electrolyte within the range of 0.05%-2% can ensure that the battery has good cycle performance.

[0046] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. An electrolyte, characterized in that: The electrolyte includes a lithium salt, a first additive, and a second additive. The lithium salt includes lithium hexafluorophosphate, the second additive is lithium fluorosulfonate, and the structure of the first additive is shown in the following formula (1): Formula (1).

2. The electrolyte according to claim 1, characterized in that The mass ratio of the first additive to the second additive is (0.5-8):

1.

3. The electrolyte according to claim 1 or 2, characterized in that The mass percentage of the first additive in the electrolyte is 0.05%-2%; and / or The mass percentage of the second additive in the electrolyte is 0.05%-2%.

4. The electrolyte according to claim 3, characterized in that The mass percentage of the first additive in the electrolyte is 0.1%-1.5%; and / or The mass percentage of the second additive in the electrolyte is 0.1%-1%.

5. The electrolyte according to claim 1 or 2, characterized in that The electrolyte further includes a lithium salt and / or a solvent.

6. The electrolyte according to claim 5, characterized in that The mass percentage of the lithium salt in the electrolyte is 10%-15%.

7. The electrolyte according to claim 5, characterized in that The solvent includes at least one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, ethylene carbonate, ethyl acetate, propyl acetate, methyl propionate, methyl acetate, ethyl propionate, propyl propionate, ethyl butyrate, methylpropyl carbonate, γ-butyrolactone and γ-valerolactone.

8. A battery, characterized in that: Comprising the electrolyte according to any one of claims 1 to 7.

9. An electrical device, characterized in that: A battery comprising the battery of claim 8.

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