WO2023134691A1 - High-voltage electrolyte and battery containing electrolyte - Google Patents

Abstract

Provided in the present disclosure are a high-voltage electrolyte and a battery containing the electrolyte, the electrolyte comprising an electrolyte salt, an organic solvent, and additives, and the additives comprising a first additive and a second additive; the first additive is selected from sulphonamide compounds, and the second additive is selected from 1,1'-sulphuryl diimidazole compounds. According to the present disclosure, by means of the synergistic effect of the first additive and the second additive, a film can be formed on the surface of the positive electrode, preventing direct contact between the electrode material and the electrolyte and stabilising the microstructure of the electrode material, reducing the dissolution of transition metal elements at a high temperature; in addition, an SEI film can also be formed on the surface of the negative electrode material, inhibiting the reduction reaction of the solvent on the negative electrode interface, and effectively improving the high-temperature storage performance, high-temperature cycle performance, low-temperature discharge performance, and thermal shock performance of the battery at a high voltage.

Description

A high-voltage electrolyte and a battery containing the electrolyte technical field

The disclosure belongs to the technical field of batteries, and relates to a high-voltage electrolyte and a battery containing the electrolyte.

Background technique

Batteries are widely used because of their high working voltage, high specific energy, long cycle life and no memory effect. At present, batteries have been widely used in the field of 3C digital consumer electronics products. With the advent of the 5G era, people have put forward higher requirements for the energy density of batteries, and increasing the charging cut-off voltage of batteries is one of the important means to increase energy density.

The electrolyte, as the "blood vessel" of the battery, plays a vital role in increasing the charge cut-off voltage of the battery. This is mainly because the electrolyte will continue to oxidize and decompose on the surface of the positive electrode under high voltage, resulting in serious deterioration of the high temperature (above 45°C) storage performance and thermal shock performance of the battery, which cannot meet the performance requirements of customers and projects.

In view of this, it is necessary to develop a high-voltage electrolyte that can effectively improve the high-temperature storage performance and thermal shock performance of the battery and take into account the kinetic performance.

Contents of the invention

In order to improve the deficiencies of the prior art, the purpose of the present disclosure is to provide a high-voltage electrolyte and a battery containing the electrolyte. The electrolyte of the present disclosure can effectively improve the performance of the battery on the basis of ensuring the kinetic performance of the battery under high voltage. High temperature cycle performance, low temperature discharge performance, high temperature storage performance and thermal shock performance.

The purpose of this disclosure is achieved through the following technical solutions:

An electrolytic solution, including an electrolyte salt, an organic solvent, and additives, the additives including a first additive and a second additive;

The first additive is selected from sulfonamide compounds, and the second additive is selected from 1,1'-sulfuryldiimidazole compounds.

According to an embodiment of the present disclosure, the first additive may be purchased from a commercial channel, or may be prepared by a method known in the art.

According to an embodiment of the present disclosure, the first additive is at least one selected from the compound shown in formula I or the compound shown in formula II:

In formula I and formula II, R _is selected from substituted or unsubstituted aryl, and if it is substituted aryl, the substituent is selected from alkyl, haloalkyl or halogen;

In formula I, R ₂ and R ₃ are the same or different, and are independently selected from alkyl groups;

In formula II, the N-containing ring group is a saturated ring group containing at least one N atom.

According to an embodiment of the present disclosure, in formula I and formula II, R ₁ is selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and the substituent is selected from C _1-6 alkyl (such as C _{1- 4} alkyl, specifically methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl), halogenated C _1-6 alkyl (for example, halogenated C _1-4 Alkyl, in particular halomethyl, haloethyl, halo-n-propyl, halo-isopropyl, halo-n-butyl, halo-isobutyl or halo-tert-butyl, also in particular trifluoro methyl) or halogen (eg F, Cl, Br or I, especially F).

According to an embodiment of the present disclosure, in formula I, R ₂ and R ₃ are the same or different, and are independently selected from C _1-6 alkyl groups, such as C _1-4 alkyl groups, specifically methyl, ethyl, n- Propyl, isopropyl, n-butyl, isobutyl or tert-butyl.

According to an embodiment of the present disclosure, in formula II, the N-containing ring group is an unsubstituted or optionally substituted saturated ring group containing at least one _N atom;

R _a is halogen, -CN, -NO ₂ , -NH ₂ , -CO-NH ₂ or the following groups that are unsubstituted or optionally substituted by one or more R _b : C _1-6 alkyl, C _{1- 6} alkoxy, C _2-6 alkenyl or C _2-6 alkynyl;

R _b is halogen, C _1-6 alkyl, C _2-6 alkenyl, C _2-6 alkynyl or C _3-6 cycloalkyl.

According to an embodiment of the present disclosure, in formula II, the saturated ring group is a 4-10 membered saturated ring group (for example, a 5-8 membered saturated ring group, specifically a 5-membered saturated ring group, a 6-membered saturated ring group, a 7-membered saturated ring group, 1-membered saturated ring group or 8-membered saturated ring group).

According to an embodiment of the present disclosure, in formula II, the N-ring group includes heteroatoms, and the number of heteroatoms may be one, two or more than three. When two or more heteroatoms are contained, one of the heteroatoms is an N atom, and the other heteroatoms may be at least one of N atoms, O atoms or S atoms.

According to an embodiment of the present disclosure, in formula II, the N-ring group is selected from one of the N-ring groups shown below:

Among them, * indicates the connection end.

According to an embodiment of the present disclosure, the first additive is selected from at least one of the following compounds 1 to 8:

According to an embodiment of the present disclosure, the second additive may be purchased from a commercial channel, or may be prepared by a method known in the art.

According to an embodiment of the present disclosure, the second additive is selected from at least one of the compounds represented by formula III:

In formula III, n ₁ is 0, 1, 2 or 3; n ₂ is 0, 1, 2 or 3;

R ₄ and R ₅ are the same or different, and are independently selected from H, halogen, cyano, or the following groups that are unsubstituted or optionally substituted by one, two or more _R'a : C _1-6 alkyl , C _2-6 alkenyl, C _1-6 alkoxy, C _1-6 alkoxycarbonyl or sulfonic acid group (-SO ₃ H);

Each R' _a is the same or different, independently selected from halogen or C _1-6 alkyl.

According to an embodiment of the present disclosure, in formula III, R ₄ and R ₅ are the same or different, and are independently selected from H, propenyl, halogen, C _1-3 alkyl, methoxy, trifluoromethyl, C _{1 -3} alkoxycarbonyl, cyano or -SO ₃ F.

According to an embodiment of the present disclosure, the second additive is selected from at least one of compound 9 to compound 14:

As the electrolyte solution described in the present disclosure, the mass percentage of the first additive to the total mass of the electrolyte solution is 0.5wt% to 4wt%, such as 0.5wt%, 1.0wt%, 1.2wt%, 1.5wt% wt%, 1.7wt%, 1.8wt%, 2wt%, 2.2wt%, 2.4wt%, 2.5wt%, 2.7wt%, 3wt%, 3.2wt%, 3.4wt%, 3.5wt%, 3.7wt%, 4wt% % or any value in the range consisting of the above-mentioned two or two values, preferably 1 wt % to 3 wt %.

The lone pair of electrons on the N atom in the N-containing unsaturated five-membered ring in the first additive and the aromatic ring (such as benzene ring) connected by the ortho position make it have a higher electron cloud density, and it is added in a small amount to There will be a strong Lewis basicity in the electrolyte. The first additive can form a complex with _PF5 in the electrolyte (the thermal stability of lithium hexafluorophosphate is poor, and the following decomposition reactions are prone to occur: _LiPF6 →LiF+ _PF5 , the generated _PF5 has active chemical properties and can be combined with electrolytic Proton impurities present in a small amount in the solution react, which causes a rapid increase in the acidity and chroma of the electrolyte, thereby deteriorating the quality of the electrolyte, reducing the battery cycle performance and high temperature performance), thereby reducing the acidity and reactivity of the electrolyte to inhibit electrolysis The increase of liquid free acid; moreover, negative electron N atoms can complex with positive electrode materials (such as lithium cobaltate) and inhibit the reactivity of the electrode surface, reduce the oxidative decomposition of the electrolyte at high temperature, and effectively inhibit the thickness expansion of high temperature storage; in addition, the The above-mentioned first additive is easily oxidized and decomposed on the surface of the positive electrode in the electrolyte to form an interfacial film, which further improves the high-temperature cycle performance and low-temperature discharge performance of the battery.

As the electrolyte solution described in the present disclosure, the mass percentage of the second additive to the total mass of the electrolyte solution is 0.5wt% to 4wt%, such as 0.5wt%, 1.0wt%, 1.2wt%, 1.5wt% wt%, 1.7wt%, 1.8wt%, 2wt%, 2.2wt%, 2.4wt%, 2.5wt%, 2.7wt%, 3wt%, 3.2wt%, 3.4wt%, 3.5wt%, 3.7wt%, 4wt% % or any value in the range consisting of the above-mentioned two or two values, preferably 1 wt % to 3 wt %.

The second additive can form a uniform and dense protective film on the surface of the positive electrode material, which reduces the unevenness of Li ⁺ embedded in the positive electrode, and at the same time inhibits the corrosion of the positive electrode material by HF, and avoids the infiltration of particles of the positive electrode material during the cycle process. The generation of cracks reduces the dissolution of transition metal elements at high temperatures. At the same time, the second additive can also be reduced on the surface of the negative electrode material (reduction potential: 1.5V vs Li ⁺ /Li) to form a dense and stable SEI film, reducing electrolysis. Oxidative decomposition of the liquid on the surface of the negative electrode material.

Further, the second additive can be decomposed into components such _{as Li2SO3} , which has lower impedance, reduces the resistance of lithium ions, and improves the low-temperature discharge performance of the battery; both the first additive and the second additive It can be oxidized to form a film at the positive electrode, and the combination of the two can further optimize the thermal stability and oxidation resistance of the film, thereby improving the thermal shock and high temperature performance of the battery.

The use of the electrolyte comprising the first additive and the second additive in the present disclosure can not only improve the high-temperature storage performance and thermal shock performance of the battery, but also take into account the high-temperature cycle performance and low-temperature discharge performance of the battery.

As the electrolyte solution described in the present disclosure, the electrolyte salt is at least one selected from electrolyte lithium salt, electrolyte sodium salt, electrolyte zinc salt, electrolyte magnesium salt and electrolyte aluminum salt.

As the electrolyte solution described in the present disclosure, the electrolyte salt includes lithium hexafluorophosphate, lithium difluorophosphate, lithium difluorobisoxalatephosphate, lithium tetrafluorooxalatephosphate, lithium oxalatephosphate, lithium bisoxalateborate, lithium difluorooxalateborate, At least one of lithium fluoroborate, lithium bisfluorosulfonyl imide and lithium bistrifluorosulfonyl imide.

As the electrolyte solution described in the present disclosure, the organic solvent includes ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, ethyl propionate, propyl propionate, ethyl acetate , at least one of ethyl n-butyrate and γ-butyrolactone.

As the electrolyte solution described in the present disclosure, the mass of the electrolyte salt accounts for 12.5wt% to 20wt% of the total mass of the electrolyte, such as 12.5wt%, 13wt%, 14wt%, 15wt%, 16wt% %, 17wt%, 18wt%, 19wt%, 20wt%, or any point value in the range consisting of two or two points above.

According to an embodiment of the present disclosure, the electrolyte is a high voltage electrolyte.

According to an embodiment of the present disclosure, the high voltage refers to a voltage greater than or equal to 4.45V.

The present disclosure also provides a method for preparing the above electrolyte, the method comprising the steps of:

mixing an electrolyte salt, an organic solvent and an additive to prepare the electrolyte;

Wherein, the additive includes a first additive and a second additive; the first additive is selected from sulfonamide compounds, and the second additive is selected from 1,1'-sulfuryldiimidazole compounds.

The present disclosure also provides a battery, which includes the above-mentioned electrolyte solution.

According to an embodiment of the present disclosure, the battery further includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet.

According to an embodiment of the present disclosure, the charging cut-off voltage of the battery is greater than or equal to 4.45V.

As an improvement of the battery described in the present disclosure, the positive electrode sheet includes a positive electrode current collector and a positive electrode membrane, and the positive electrode membrane includes a positive electrode active material, and the positive electrode active material is LiCoO ₂ , LiNiO ₂ , LiCo _y M One or more of _1-y O ₂ , LiNi _y M _1-y O ₂ , LiMn _y M _1-y O ₂ and LiNi _1-xyz Co _x Mn _y M _z O ₂ , wherein M is selected from One or two of Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti, 0≤x≤1, 0≤y≤1,0 ≤z≤1 and 0≤x+y+z≤1.

As an improvement of the battery described in the present disclosure, the negative electrode sheet includes a negative electrode current collector and a negative electrode membrane, and the negative electrode membrane includes a negative electrode active material, and the negative electrode active material is artificial graphite, natural graphite, lithium titanate and at least one of silicon-carbon composite materials composed of SiO _w and graphite, 1<w<2.

Beneficial effects of the present disclosure:

The present disclosure provides a high-voltage electrolyte and a battery containing the electrolyte, the electrolyte includes an electrolyte salt, an organic solvent and an additive, the additive includes a first additive and a second additive; the first additive is selected from Sulfonamide compounds, the second additive is selected from 1,1'-sulfuryl diimidazole compounds.

Through the synergistic effect of the first additive and the second additive, the present disclosure can form a film on the surface of the positive electrode, avoid direct contact between the electrode material and the electrolyte, stabilize the microstructure of the electrode material, and reduce the dissolution of transition metal elements at high temperatures. It can also form an SEI film on the surface of the negative electrode material, inhibit the reduction reaction of the solvent at the negative electrode interface, and effectively improve the high-temperature storage performance, high-temperature cycle performance, low-temperature discharge performance and thermal shock performance of the battery under high voltage.

Detailed ways

The present disclosure will be further described in detail in conjunction with specific embodiments below. It should be understood that the following examples are only for illustrating and explaining the present disclosure, and should not be construed as limiting the protection scope of the present disclosure. All technologies implemented based on the above contents of the present disclosure are covered within the intended protection scope of the present disclosure.

The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples can be obtained from commercial sources unless otherwise specified.

In the description of the present disclosure, it should be noted that the terms "first", "second" and so on are only used for descriptive purposes, and do not indicate or imply relative importance.

Example 1

In an argon-filled glove box (oxygen content ≤ 1ppm, water content ≤ 1ppm), mix ethylene carbonate, propylene carbonate and propyl propionate in a mass ratio of EC:PC:PP=2:1:7 , then slowly add 12.5wt% lithium hexafluorophosphate (LiPF ₆ ) based on the total weight of the electrolyte to the mixed solution, and finally add 1.0wt% of the first additive and 1.5wt% of the second additive based on the total weight of the electrolyte (the specific structural formula is shown in the table 1), after stirring uniformly, the electrolyte solution of Example 1 was obtained.

Embodiment 2～17 and comparative example 1～2

In Examples 2-17 and Comparative Examples 1-2, except that the amount and selection of the first additive and the second additive in the electrolyte are added as shown in Table 1, the others are the same as in Example 1.

The electrolyte composition of table 1 embodiment and comparative example

the	The first additive and content	The second additive and content
Example 1	1 wt% compound 1	1.5 wt% compound 9
Example 2	1 wt% Compound 1	1.5 wt% compound 10
Example 3	1 wt% Compound 1	1.5 wt% Compound 11
Example 4	1 wt% Compound 1	1.5 wt% Compound 12
Example 5	1 wt% Compound 1	1.5 wt% Compound 13
Example 6	1 wt% Compound 1	1.5 wt% compound 14
Example 7	1 wt% Compound 2	1.5 wt% Compound 9
Example 8	1 wt% Compound 3	1.5 wt% Compound 9
Example 9	1 wt% Compound 4	1.5 wt% compound 9
Example 10	1 wt% compound 5	1.5 wt% compound 9
Example 11	1 wt% compound 6	1.5 wt% compound 9
Example 12	1 wt% compound 7	1.5 wt% compound 9
Example 13	1 wt% Compound 8	1.5 wt% compound 9
Example 14	0.3 wt% Compound 1	1.5 wt% Compound 9
Example 15	4 wt% compound 1	1.5 wt% compound 9
Example 16	1 wt% Compound 1	0.3 wt% compound 9
Example 17	1 wt% Compound 1	4 wt% compound 9
Comparative example 1	/	1.5 wt% compound 9
Comparative example 2	1 wt% compound 1	/

test case

1. Assembling batteries: use the electrolytes of the above-mentioned Examples 1-17 and Comparative Examples 1-2 as the electrolytes of the batteries respectively, and assemble them into soft-pack batteries, wherein,

Diaphragm: PP diaphragm;

Positive pole piece: the positive current collector is aluminum foil, and the positive coating is composed of lithium cobalt oxide, acetylene black and polyvinylidene fluoride PVDF with a mass ratio of 95:3:2;

Negative electrode sheet: The negative electrode current collector is copper foil, and the negative electrode coating is composed of artificial graphite, acetylene black and styrene-butadiene rubber (SBR) with a mass ratio of 94:3:3.

After stacking the positive pole piece, the negative pole piece and the PP separator in sequence, add the electrolytes prepared in Examples 1-17 and Comparative Examples 1-2 to assemble soft-pack batteries, which are respectively recorded as test batteries 1-17 and comparative batteries 1~2.

2. Electrochemical performance test: use the blue electric charge and discharge test cabinet to conduct electrochemical performance test through the following test methods:

(1) High temperature cycle performance test

High-temperature cycle performance test: At 45°C, charge the divided battery to 4.50V at 0.7C constant current and constant voltage, cut-off current at 0.05C, and then discharge at 0.5C constant current to 3.0V, and cycle accordingly. After 300 cycles, calculate the capacity retention rate at the 300th week, and the calculation formula is as follows:

The 300th cycle cycle capacity retention rate (%)=(300th cycle discharge capacity/first cycle discharge capacity)×100%.

(2) 14-day high-temperature storage test at 60°C

Put the battery at room temperature and charge and discharge once at 0.5C (4.50V～3.0V), record the discharge capacity C0 of the battery before storage, then charge the battery with a constant current and constant voltage to a full state of 4.50V, and use a vernier caliper to test the battery for high temperature storage Thickness d1 (connect the two diagonal lines of the above battery respectively through a straight line, and the intersection point of the two diagonal lines is the battery thickness test point), put the battery in a 60°C incubator and store it for 14 days, and take it out after storage Test the thermal thickness d2 of the battery after storage, and calculate the battery thickness expansion rate after the battery is stored at 60°C for 14 days; after the battery is cooled at room temperature for 24 hours, discharge the battery at a constant current of 0.5C to 3.0V again, and then discharge it at a constant current of 0.5C Charge to 4.50V at constant current and voltage, record the discharge capacity C1 and charge capacity C2 of the battery after storage, and calculate the residual capacity retention rate and recovery capacity retention rate after the battery is stored at 60°C for 14 days. The calculation formula is as follows:

Thickness expansion rate after storage at 60°C for 14 days = (d2-d1)/d1*100%;

Residual capacity retention after storage at 60°C for 14 days = C1/C0*100%;

After storage at 60°C for 14 days, the recovery capacity retention rate=C2/C0*100%.

(3) Low temperature discharge performance test

Under the ambient conditions of 25°C, discharge the battery after 0.5C to 3.0V, and leave it for 5 minutes; then charge it to 4.50V at 0.2C, and when the cell voltage reaches 4.50V, change to 4.50V constant voltage charge until charging The current is less than or equal to the given cut-off current of 0.05C, and put it aside for 5 minutes; transfer the fully charged core to a high and low temperature box, set it to -10°C, and wait for 120 minutes after the temperature of the incubator reaches; then discharge it at 0.2C to the cut-off voltage of 3.0V , put it aside for 5 minutes; then adjust the temperature of the high and low temperature box to 25°C±3°C, and wait for 60 minutes after the temperature of the incubator reaches the temperature; then charge it to 4.50V at 0.2C, and when the battery voltage reaches 4.50V, change it to 4.50V Charge at a constant voltage until the charging current is less than or equal to the given cut-off current of 0.05C; leave it on hold for 5 minutes; calculate the 3.0V capacity retention rate for low-temperature discharge at -10°C. Calculated as follows:

-10°C discharge 3.0V capacity retention rate (%)=(-10°C discharge to 3.0V discharge capacity/25°C discharge to 3.0V discharge capacity)×100%.

(4) thermal shock performance

Under the ambient conditions of 25°C, discharge to 3.0V with a given current of 0.2C; hold for 5 minutes; charge with a charging current of 0.2C to 4.50V, when the cell voltage reaches 4.50V, change to 4.50V constant voltage charge until charging The current is less than or equal to the given cut-off current of 0.05C; put the cell into the oven after leaving it on hold for 1 hour, and the temperature of the oven rises to 130°C±2°C at a rate of 5°C±2°C/min, and stops after 30 minutes. If the core does not ignite or explode, it is a pass.

Table 2 Comparison of the test results of the battery assembled with the electrolyte of Examples 1-17 and Comparative Examples 1-2

By comparative example 1～2 and the test result of embodiment 1～17 in table 2, it can be seen that:

The synergistic effect of the first additive and the second additive not only inhibits the increase of the acidity of the electrolyte, but also forms an interface protective film on the surface of the positive and negative electrodes, which is conducive to improving the stability of the battery interface and further improving the high temperature of the battery under high voltage. Storage performance, high temperature cycle performance, low temperature discharge performance and thermal shock performance.

In addition, in Example 14, because the addition amount of the first additive was too small, the formation of an incomplete interfacial film resulted in poor thermal shock performance, high-temperature cycle performance, low-temperature discharge performance and high-temperature storage performance of the battery. In Example 15, because the addition amount of the first additive is too large, the interfacial film is too thick and the impedance is large, resulting in a decline in the high-temperature cycle performance, low-temperature discharge performance and high-temperature storage performance of the battery. In Example 16, thermal shock performance, high-temperature cycle performance and high-temperature storage performance deteriorated due to the low addition amount of the second additive compound. In Example 17, because the addition amount of the second additive is too large, the impedance is too large, and the high-temperature storage gas production increases.

Because Comparative Example 1 does not contain the first additive, the thermal shock performance, high-temperature cycle performance and low-temperature discharge performance of the battery are obviously deteriorated. Because Comparative Example 2 does not contain the second additive, the thermal shock performance, high-temperature cycle performance and low-temperature discharge performance of the battery deteriorate significantly.

The applicant declares that the present disclosure illustrates the detailed process equipment and process flow of the present disclosure through the above-mentioned examples, but the present disclosure is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present disclosure must rely on the above-mentioned detailed process equipment and process flow. process can be implemented. Those skilled in the art should understand that any improvement to the present disclosure, the equivalent replacement of each raw material of the disclosed product, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present disclosure.

The embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above-mentioned embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims (15)

1. An electrolytic solution, including electrolyte salt, organic solvent and additives, characterized in that the additives include a first additive and a second additive;

   The first additive is selected from sulfonamide compounds, and the second additive is selected from 1,1'-sulfuryldiimidazole compounds.
2. The electrolyte solution according to claim 1, wherein the first additive is selected from at least one of the compounds shown in formula I or the compound shown in formula II:

   

   In formula I and formula II, _R is selected from substituted or unsubstituted aryl, and if it is substituted aryl, the substituent is selected from alkyl, haloalkyl or halogen;

   In formula I, R ₂ and R ₃ are the same or different, and are independently selected from alkyl groups;

   In formula II, the N-containing ring group is a saturated ring group containing at least one N atom.
3. The electrolyte according to claim 2, wherein, in formula I and formula II, _R is selected from substituted or unsubstituted phenyl or substituted or unsubstituted naphthyl, wherein the substituent is selected from C _{1- 6} alkyl, halogenated C _1-6 alkyl or halogen;

   Preferably, in the formula I, R ₂ and R ₃ are the same or different, and are independently selected from C _1-6 alkyl groups.
4. The electrolyte solution according to claim 2 or 3, characterized in that, in the formula II, the N-containing ring group is unsubstituted or optionally substituted by one or more R _a containing at least one N atom Saturated ring group;

   R _a is halogen, -CN, -NO ₂ , -NH ₂ , -CO-NH ₂ or the following groups that are unsubstituted or optionally substituted by one or more R _b : C _1-6 alkyl, C _{1- 6} alkoxy, C _2-6 alkenyl or C _2-6 alkynyl;

   R _b is halogen, C _1-6 alkyl, C _2-6 alkenyl, C _2-6 alkynyl or C _3-6 cycloalkyl.
5. Electrolyte solution according to claim 4, is characterized in that, described saturated cyclic group is 4-10 membered saturated cyclic group.
6. The electrolytic solution according to any one of claims 2-5, characterized in that, in formula II, the N-ring group is selected from one of the N-ring groups shown below:

   

   Among them, * indicates the connection end.
7. The electrolyte solution according to any one of claims 1-6, wherein the first additive is selected from at least one of the following compounds 1 to 8:

   
8. The electrolyte according to any one of claims 1-7, wherein the second additive is selected from at least one of the compounds shown in formula III:

   

   In formula III, n ₁ is 0, 1, 2 or 3; n ₂ is 0, 1, 2 or 3;

   R ₄ and R ₅ are the same or different, and are independently selected from H, halogen, cyano, or the following groups that are unsubstituted or optionally substituted by one, two or more _R'a : C _1-6 alkyl , C _2-6 alkenyl, C _1-6 alkoxy, C _1-6 alkoxycarbonyl or sulfonic acid group (-SO ₃ H);

   Each R' _a is the same or different, independently selected from halogen or C _1-6 alkyl.
9. The electrolyte solution according to claim 8, wherein, in formula III, R and _R are the same or different, independently _selected from H, propenyl, halogen, C _1-3 alkyl, methoxy, Trifluoromethyl, C _1-3 alkoxycarbonyl, cyano or -SO ₃ F.
10. The electrolyte according to any one of claims 1-9, wherein the second additive is selected from at least one of compound 9 to compound 14:

    

    
11. The electrolytic solution according to any one of claims 1-10, characterized in that the mass of the first additive accounts for 0.5wt% to 4wt% of the total mass of the electrolytic solution, preferably 1wt% to 3 wt%.
12. The electrolyte solution according to any one of claims 1-11, characterized in that, the percentage of the mass of the second additive to the total mass of the electrolyte is 0.5wt%-4wt%, preferably 1wt%- 3 wt%.
13. The electrolyte solution according to any one of claims 1-12, wherein the electrolyte salt is selected from at least one of electrolyte lithium salt, electrolyte sodium salt, electrolyte zinc salt, electrolyte magnesium salt and electrolyte aluminum salt;

    Preferably, the electrolyte salt includes lithium hexafluorophosphate, lithium difluorophosphate, lithium difluorobisoxalatephosphate, lithium tetrafluorooxalatephosphate, lithium oxalatephosphate, lithium bisoxalateborate, lithium difluorooxalateborate, lithium tetrafluoroborate, bistrifluoroborate At least one of lithium fluorosulfonyl imide and lithium bisfluorosulfonyl imide;

    More preferably, the mass percentage of the electrolyte salt to the total mass of the electrolyte is 12.5wt%-20wt%.
14. The electrolyte according to any one of claims 1-13, wherein the organic solvent comprises ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, ethyl propionate At least one of ester, propyl propionate, ethyl acetate, ethyl n-butyrate and γ-butyrolactone.
15. A battery, characterized in that the battery comprises the electrolyte solution according to any one of claims 1-14.