WO2015070447A1

WO2015070447A1 - High-voltage non-aqueous electrolyte solution and high-voltage non-aqueous electrolyte solution secondary battery

Info

Publication number: WO2015070447A1
Application number: PCT/CN2013/087300
Authority: WO
Inventors: 黄学杰; 林明翔; 王昊; 陈瀚林; 胡小春
Original assignee: 中国科学院物理研究所; 苏州氟特电池材料有限公司; 上海图尔实业发展有限公司
Priority date: 2013-11-18
Filing date: 2013-11-18
Publication date: 2015-05-21

Abstract

A high-voltage non-aqueous electrolyte solution and a high-voltage non-aqueous electrolyte solution secondary battery. The high-voltage non-aqueous electrolyte solution comprises a lithium salt and, dissolving the lithium salt, a non-aqueous solvent and an additive; the additive is selected from at least one of the compounds as represented by formula (I), where: R1 is F, a C1-C8 alkyl group, a C1-C8 fluoroalkyl group or a C1-C8 fluoroalkoxy group, and R2 is a C1-C8 fluoroalkyl group or a C1-C8 fluoroalkoxy group. The high-voltage non-aqueous electrolyte solution secondary battery can form on a positive electrode surface thereof a protective layer by being charged initially to a high voltage such as 5.1 V, thus increasing the use performance of the high-voltage non-aqueous electrolyte solution secondary battery. The secondary battery has a charging cut-off voltage of 4.7 to 4.9 V, a high operating voltage platform, a high energy density, a low cycle capacity fade, a high charging/discharging coulomb efficiency, a great performance in withstanding high temperatures, and a wide range of applications.

Description

High voltage non-aqueous electrolyte and high voltage non-aqueous electrolyte secondary battery

The present invention relates to a non-aqueous electrolyte solution and a non-aqueous electrolyte secondary battery, and more particularly to a high-voltage non-aqueous electrolyte solution and a high-voltage non-aqueous electrolyte secondary battery.

Background technique

A secondary battery, also called a rechargeable battery or a battery, refers to a battery that can be activated by the activation of the active substance after the battery is discharged. A lithium ion battery is a secondary battery that is intercalated and deintercalated by a helium ion between a positive electrode and a negative electrode, and generally has a carbon material as a negative electrode and a lithium-containing compound as a positive electrode because of a specific energy. It has the advantages of high working voltage, wide application temperature range, low self-discharge rate, long cycle life and no pollution. It has been widely used as a mobile power source for mobile phones, portable computers, video cameras, and other vehicles.

In the development of lithium-ion batteries, cathode materials are the core bottleneck restricting their large-scale application. The cathode materials widely used at present include lithium gallium ateate (LiCo0 ₂ ), lithium iron phosphate (LiFeP0 ₄ ), spinel-type lithium manganate (ϋΜη ₂ 0 ₄ ), etc., wherein 0) 0 ₂ is high in cost, and i is charging When the voltage exceeds 4.2V, phase change and oxygen loss occur, and there is a certain safety hazard. Although LiFeP0 ₄ has the advantages of rich source and non-toxicity, its discharge platform is low (3.4V), and it is difficult to obtain high energy density: LiMn ₂ 0 ₄ due to the existence of HF in the electrolytic solution caused by dissolution of manganese as well as structural changes in the charge and discharge process, which causes at room temperature, especially at high temperatures (above 50 C) fast capacity fading.

Aiming at the properties of different cathode materials and their defects, researchers at home and abroad have conducted a large number of related researches to improve the positive electrode performance of lithium ion batteries. The use of metal materials to coat the positive electrode materials is a more effective solution. The barrier layer coated on the surface of the positive electrode material can be used to isolate the positive electrode material from the electrolyte, thereby effectively preventing the adverse interaction between the two, and can also be used to improve the conductivity of the positive electrode material, thereby improving the thermal stability of the positive electrode material. Properties, high temperature performance, cycle stability and discharge rate characteristics. However, the coating method can only protect the positive electrode material, and cannot simultaneously protect the additive materials such as conductive additives. The carbon black as a conductive additive is easily oxidized at a high voltage, and is particularly noticeable when the operating temperature is high.

Improving the working voltage of lithium-ion batteries is the development direction of high-energy lithium-ion battery technology. There are reports including spinel-type lithium nickel manganate (Li iasMn^ lithium cobalt phosphate (LiCoP0 ₄ ), lithium nickel phosphate (Li iP0 ₄ ), etc. These materials are used in lithium ion batteries to increase the output voltage and energy density of the battery. It is beneficial to further broaden the range of use of lithium-ion batteries in high-power electrical equipment, which has attracted wide attention of researchers in the industry. However, due to the electrochemical oxidation of conventional electrolytes based on UPF ₆ carbonate solution above 4.5 V Decomposition, which leads to the actual obstruction of these materials.

At present, high-voltage electrolyte solvents widely studied at home and abroad include fluorinated solvents, nitrile solvents, and sulfone solvents. However, related studies have shown: Lithium salts: LiPF ₆ solubility in low-polarity fluorinated solvents Poor, and the nitrile and sulfone solvents have poor compatibility with low potential anodes such as graphite of lithium ion batteries. Therefore, the development and functionalization of functional additives for high-voltage electrolytes is the most economical and effective method for improving the compatibility of high-voltage electrodes with electrolytes and improving the electrochemical performance of batteries. Summary of the invention

The present invention provides a high-voltage non-aqueous electrolyte solution and a high-voltage non-aqueous electrolyte secondary battery, wherein at least one of the compounds represented by the general formula (I) is added as a high voltage to the high-voltage non-aqueous electrolyte solution. The non-aqueous electrolyte additive is a high-voltage non-aqueous electrolyte secondary battery prepared by using an electrolyte containing the compound, which has high energy density, reduced cycle capacity, high coulombic efficiency, and excellent high-temperature resistance.

The present invention also provides a high voltage nonaqueous electrolyte secondary battery prepared by using the above high voltage nonaqueous electrolyte and a method for improving the performance of the high voltage nonaqueous electrolyte secondary battery, which can be better The performance of the high voltage nonaqueous electrolyte secondary battery is improved.

In the present invention, the high voltage means that the operating voltage of the electrolyte/secondary battery is 4.5 V, particularly the operating voltage is 4.7 to 4.9 V unless otherwise specified.

In one aspect of the invention, there is provided the use of at least one of the compounds represented by the following formula (I) as a high-voltage non-aqueous electrolyte additive,

O jj® o

J z , , . _s , ( J )

Rl " ' SS IS , , R2

O O

In the formula: R1 is F, C1~C8 hydrocarbon sulfhydryl (S卩C _TO H _2TO+ , m = l~8), C1~C8 fluoroindenyl (ie C„F ₂ „ ₊ , n = l~8) or C1 ~C8 fluorodecyloxy;

R2 is a C1~C8 fluoroindenyl group (i.e., C„F ₂ „ ₊ , n = 1 to 8) or a fluorodecyloxy group.

Further, the fluorine in the C1~C8 fluoroindenyl group may be partially substituted, such as a monofluoroindenyl group, a difluoroanthracenyl group, or a perfluorofluorenyl group; the C1~C8 fluoroanthracene; The fluorenyl group in the group may be a linear fluorenyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group or the like, or a branched fluorenyl group such as an isopropyl group, an isobutyl group or a different group. A pentyl group, an isooctyl group or the like may also be a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclohexyl group or the like.

According to the application of the present invention, wherein R1 is F, C1~C3 hydrocarbon hydrazino, CF ₃ CH ₂ 0- or (CF ₃ ) ₂ CHO-, and R ₂ is a C1~C4 perfluorodecyl group. Further, CF ₃ CH ₂ 0- or (CF ₃ ) ₂ CHO- _; further, the R 1 is F or a C 1 -C 3 hydrocarbon group, and the R 2 is a Cl~C4 perfluoroindenyl group; The R1 is CH ₃ and the R 2 is CF ₃ .

The compound of the formula (I) of the present invention can be produced by the methods reported in the following literature:

Document 1: Hong-Bo Han, Yi-Xuan Zhou, Kai Liu, et al. Efficient Preparation of (Fluorosulfonyl) (pentafluoroethanesulfonyl) imide and Its Alkali Salts. Chem. Lett, 2010, 39: 472~474.

Literature 2: Zhang Heng, Han Hongbo, Gong Shouzhe, et al. Characterization and properties of a new lithium salt Li[N(S0 ₂ OCH(CF ₃ ) ₂ ) ₂ ] electrolyte. Chinese Science Bulletin, 2012, 57(27): 2623 ~ 2631 .

The present invention also provides a high voltage nonaqueous electrolyte comprising a lithium salt, a nonaqueous solvent in which the lithium salt is dissolved, and an additive selected from at least one of the compounds represented by the above formula (I). And the mass percentage of the additive in the high voltage non-aqueous electrolyte is 0.05 to 10%. Further, the preferred mass percentage of the additive in the high voltage nonaqueous electrolyte is from 0.5 to 5%.

The high-voltage non-aqueous electrolyte solution according to the present invention can be obtained by directly adding at least one of the compounds represented by the above formula (I) to a commercially available ordinary non-aqueous electrolyte solution, or by using a conventional lithium salt. At least one of the nonaqueous solvent and the compound represented by the above formula (I) is obtained by mixing. The high-voltage non-aqueous electrolyte according to the present invention is suitable for a non-aqueous electrolyte secondary battery, such as a lithium secondary battery. The lithium salt of the present invention is not particularly limited, and a lithium salt conventionally used in a nonaqueous electrolytic solution in the prior art is suitable for use in the present invention. In a specific embodiment of the invention, the lithium salt is selected from the group consisting of LiPF ₆ , LiBF ₄ , LiAsF ₆ , CF ₃ S0 ₃ Li, Li[N ( FS0 ₂ ) ₂ ] (LiFSI), Li[N ( CF ₃ S0 ₂ ) ₂ ] one or more of (LiTFSI), Li[N (C ₂ F ₅ S0 ₂ ) ₂ ] (LiBETI) , Li[C (C ₂ F ₅ S0 ₂ ) ₃ ]; The lithium salt is preferably one or more of LiPF ₆ , LiBF ₄ , LiFSK LiTFSK LiBETI; more specifically, the lithium salt is preferably LiPF ₆ . Further, the present invention is not particularly limited to the molar concentration of the lithium salt in the high-voltage nonaqueous electrolytic solution, and any lithium salt concentration which does not impair the technical effects of the present invention is suitable for the present invention. In a specific aspect of the invention, the molar concentration of the lithium salt in the high-voltage non-aqueous electrolyte solution is 0.3 to 3 mol/L; and further, the molar concentration of the lithium salt is preferably 0.5 to 2 mol/L.

The high-voltage non-aqueous electrolyte according to the present invention, wherein the non-aqueous solvent is used for dissolving the lithium salt, and the non-aqueous solvent of the present invention is not particularly limited as long as it is conventionally used without impairing the technical effects of the present invention. The solvent of the nonaqueous electrolytic solution is suitable for use in the present invention, and may include, but is not limited to, one or more of a carbonate, a carboxylate, an ether, a sulfone, and a ketone. In a specific embodiment of the present invention, the carbonate is selected from one or more of a C2 to C5 cyclic carbonate and a C3 to C7 chain carbonate; in particular, the C2 to C5 cyclic carbonate is selected from the group consisting of Ethylene carbonate (EC) or propylene carbonate (PC), the C3 to C7 chain carbonate is selected from the group consisting of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) or diethyl carbonate (DEC). Further, the nonaqueous solvent is a mixed solvent of a C2 to C5 cyclic carbonate and a C3 to C7 chain carbonate, and a volume ratio of the cyclic carbonate to the chain carbonate in the mixed solvent is 1:9. ~9:1; Further, the non-aqueous solvent is specifically a mixture of EC and DMC in a volume ratio of 1:9-9:1, an EC and EMC mixed solvent or volume in a volume ratio of 1:9 to 9:1. An EC and DEC mixed solvent of 1:9 to 9:1.

The high-voltage non-aqueous electrolyte of the present invention may further comprise an auxiliary agent (ie, a functional additive) for improving certain properties of the non-aqueous electrolyte secondary battery, such as improving the interface properties between the negative electrode and the electrolyte. Solid Electrolyte Interface (SEI) Membrane properties, improve electrolyte low temperature performance, improve electrolyte conductivity, improve electrolyte thermal stability, improve battery safety, and improve electrolyte cycle performance. The auxiliaries of the present invention are not particularly limited as long as the auxiliaries which do not impair the technical effects of the present invention are suitable for use in the present invention, and the auxiliaries may include, but are not limited to, film forming auxiliaries, conductive auxiliaries, flame retardant auxiliaries, Anti-over-filler, stabilizer, more One or more of the functional auxiliaries. In a specific embodiment of the present invention, the auxiliary agent is specifically a film-forming auxiliary agent, including but not limited to vinylene carbonate (VC), fluorovinylene carbonate (FEC), propane sultone (PS), One or more of vinyl sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, dimethyl sulfoxide.

In particular, the present invention has no particular limitation on the mass percentage of the auxiliary agent in the high-voltage non-aqueous electrolyte solution, and may be, for example, 0.01 to 5%, and further may be 0.1 to 3%, and further may be 0.2. ~1%.

The present invention also provides a high voltage nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode and the above nonaqueous electrolyte, wherein the positive electrode has a positive active material capable of reversibly deintercalating lithium ions, and the negative electrode has reversible A lithium ion-doped negative active material.

The high voltage nonaqueous electrolyte secondary battery according to the present invention, wherein the positive electrode active material may be a lithium transition metal composite oxide material such as lithium cobalt oxide, lithium nickel oxide or lithium manganese oxide, or may be The surface-modified lithium transition metal composite oxide material, such as a lithium transition metal composite oxide material coated with a metal material. The present invention is not particularly limited to the positive electrode active material. In a specific embodiment, the positive electrode active material is selected from the group consisting of a layered lithium manganese-based oxide, a doped lithium manganese oxide, or a surface-modified lithium manganese oxide. One or more, one selected from the group consisting of a layered high voltage lithium-rich manganese-based positive electrode material, a spinel-like lithium nickel manganese oxide material (LiMn ₂ 0 ₄ ) or coated with A1 ₂ 0 ₃ , MgO, Zr0 ₂ surface modification layer of LiNi sMn^C^

The high voltage nonaqueous electrolyte secondary battery according to the present invention, wherein the anode active material may be selected from the group consisting of metallic lithium, natural graphite, artificial graphite, hard carbon, soft carbon, Li-Sn alloy, Li-Sn-0. One or more of alloy, Sn, SnO, SnO ₂ , lithiated lithiated Ti0 ₂ , Li ₄ Ti ₅ 0 ₁₂ , Li-Al alloy, silicon, Li-Si alloy, and silicon-based composite material. The negative active material of the present invention is not particularly limited. In a specific embodiment, the negative active material is selected from the group consisting of artificial graphite, Li ₄ Ti ₅ 0 ₁₂ or metallic lithium.

Further, the high voltage nonaqueous electrolyte secondary battery further includes a separator disposed between the positive electrode and the negative electrode. The material and shape of the separator are not particularly limited as long as they are stable in the electrolytic solution and excellent in liquid retention, and may be a porous sheet or nonwoven fabric made of polyolefin such as polyethylene or polypropylene. In addition, the high-voltage non-aqueous electrolyte secondary battery further includes an outer casing, and the outer casing may be made of any material such as nickel-plated iron, stainless steel, aluminum or alloy thereof, nickel, titanium. And aluminum-plastic composite packaging film. The operating voltage of the high voltage nonaqueous electrolyte secondary battery of the present invention described above can be as high as 4.7 V to 4.9 V.

The present invention also provides a method for preparing a high voltage nonaqueous electrolyte secondary battery, comprising preparing a positive electrode and a negative electrode using a positive electrode active material and a negative electrode active material, respectively;

Dissolving at least one of a lithium salt and a compound represented by the above formula (I) in a nonaqueous solvent to obtain a nonaqueous electrolytic solution;

The positive electrode, the negative electrode, and the nonaqueous electrolytic solution are assembled into a high voltage nonaqueous electrolyte secondary battery.

According to the preparation method of the present invention, the assembly can be carried out by a conventional method, such as by placing a separator between the positive electrode and the negative electrode, and then inserting the positive electrode-separator-negative electrode into the outer casing, and then The non-aqueous electrolyte solution is injected into the outer casing to prepare the high-voltage non-aqueous electrolyte secondary battery.

Further, the preparation method of the present invention further comprises: charging the high-voltage non-aqueous electrolyte secondary battery for the first time, and controlling the charge cut-off voltage at the time of the first charge to be at least 5.1V.

The present invention also provides a high voltage nonaqueous electrolyte secondary battery produced by the above production method.

The present invention also provides a method of using the high voltage nonaqueous electrolyte secondary battery described above, comprising: charging the high voltage nonaqueous electrolyte secondary battery for the first time, and controlling the charge cutoff voltage at the time of the first charge to be at least 5.1. V. Further, the current density at the time of the first charge is 0.01 to 10 mA/cm ² , and may be, for example, 0.05 mA/cm ² . When the high-voltage non-aqueous electrolyte secondary battery is subsequently charged, the charge cut-off voltage for subsequent charging can be controlled to be 4.7 to 4.9 V, and the discharge cut-off voltage is 3.0 to 3.5 V.

The present invention also provides a method for improving the performance of the high-voltage non-aqueous electrolyte secondary battery, comprising: charging the high-voltage non-aqueous electrolyte secondary battery for the first time, and controlling the charge cut-off voltage at the time of the first charge to be at least 5.1V. Further, the current density at the time of the first charge is 0.01 to 10 mA/cm ² . The mechanism for improving the performance of the above high-voltage non-aqueous electrolyte secondary battery is mainly because the method can form a protective layer on the positive electrode surface of the secondary electrode, thereby effectively protecting the positive electrode material and preventing the positive electrode and the electrolyte. Bad interactions between. The implementation of the solution of the present invention has at least the following advantages:

1. The present invention uses at least one of the compounds represented by the general formula (I) as a high-voltage non-aqueous electrolyte additive, which can be directly added to a conventional electrolyte or mixed with a conventional lithium salt and an organic solvent. After use, the non-aqueous electrolyte added with the compound is not easily decomposed under a high voltage of 5V, which is favorable for promoting the popularization and application of the high-voltage positive electrode material.

2. The high-voltage non-aqueous electrolyte of the present invention has a simple preparation process, and the non-aqueous electrolyte secondary battery can improve the output voltage and power density of the secondary battery, thereby facilitating further widening the lithium-ion battery at high power. The range of use on electrical equipment.

3. The high voltage nonaqueous secondary battery of the present invention has an operating voltage of 4.7 to 4.9 V, high energy density, reduced cycle capacity, high coulombic efficiency, and excellent high temperature resistance, and has a wide range of applications.

4. The method for forming a protective layer on the positive electrode of a high-voltage non-aqueous electrolyte secondary battery is simple and easy to operate, and it is not necessary to prepare the electrode of the positive electrode material, and can be formed only at the time of first charging, the method can Better improve the performance of high voltage non-aqueous electrolyte secondary batteries.

DRAWINGS

1 is a charge and discharge curve of the first week of the high voltage nonaqueous electrolyte secondary battery of Example 1. FIG. 2 is a graph showing the coulomb efficiency of the batteries of Example 1 and Comparative Example 1 under the test conditions of 25 ° C as a function of the number of cycles. Trend;

Fig. 3 is a graph showing the trend of the Coulomb efficiency with the number of cycles of the batteries of Example 1 and Comparative Example 1 under the test conditions of 55 °C. detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. It is obvious that the described embodiments are a part of the embodiments of the present invention. , not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Example 1

l R2

The structural formula of the additive used in this embodiment is o ο

Wherein R1 is -CH _3, R2 is -CF _3.

2. Preparation of high voltage non-aqueous electrolyte

At room temperature (25 ° C), 500 mL of ethylene carbonate (EC) and 500 mL of dimethyl carbonate (DMC) were uniformly mixed in a glove box to prepare a nonaqueous solvent, wherein the nonaqueous solvent was EC and DMC. Volume ratio is 1: 1;

To the non-aqueous solvent, 152 g of a lithium salt and 10 g of the additive of the above structural formula are added, and after stirring, a high-voltage non-aqueous electrolyte solution is obtained. In the present embodiment, the lithium salt used is lithium hexafluorophosphate (LiPF ₆ , purchased from Henan Fluoride) having a molar concentration of 1 mol/L, and the additive has a mass content of 1 wt% in the high voltage nonaqueous electrolyte.

3, preparation of positive and negative

Spinel-like lithium nickel manganese oxide (LiNi. ₅ M _ni . ₅ 0 ₄ , purchased from Shandong Qixing Energy Materials Co., Ltd.) as a positive electrode active material, polyvinylidene fluoride (PVDF) as a binder And carbon black as a conductive agent is dispersed in yttrium, yttrium-dimethylpyrrolidone (NMP) in a weight ratio of 90:5:5, and uniformly mixed to form a positive electrode composite slurry;

The positive electrode composite slurry was uniformly coated on an aluminum foil (as a current collector) having a thickness of 15 μΓΠ, dried at 60° C. to form a film having a thickness of 50 μΓΠ, and then pressed under a pressure of 1 MPaxl ^{2 2} . Continue to dry at 100 ° C for 12 hours to obtain a pole piece; cut the pole piece into a 1 cm ² area as a positive electrode;

The negative electrode was made of mesocarbon microbeads (MCMB, purchased from Ningbo Shanshan Technology Co., Ltd.) as a negative electrode active material, and the current collector was 9 μm of copper foil. The negative electrode was fabricated by general coating and compaction.

4. Preparation of high voltage non-aqueous electrolyte secondary battery

The dried positive electrode was placed in an argon glove box, and a 2325 porous film (purchased from Ube, Japan) was placed as a separator between the positive electrode and the negative electrode, and the high-voltage non-aqueous electrolyte prepared above was added dropwise to complete the electrode sheet. Infiltrated and assembled to obtain a high-voltage non-aqueous electrolyte secondary battery (referred to as A1). The high-voltage non-aqueous electrolyte secondary battery prepared above was subjected to a charge and discharge cycle test using an automatic charge and discharge device (LAND, Wuhan Jinnuo Technology Co., Ltd.); wherein, the current density during charge and discharge control was 0.05 mA/cm ² , The charge cutoff voltage during the first week of charging is 5.1V, the charge cutoff voltage during subsequent charging is 4.7V, and the discharge cutoff voltage is 3V. The charge and discharge curve is shown in Figure 1.

As can be seen from Fig. 1, when the charge cut-off voltage is about 4.7V, lithium ions in the electrode material are deintercalated, and the material specific capacitance reaches about 150 mAh/g. As the charge cut-off voltage continues to rise, the electrolyte begins to decompose. Example 2

A high-voltage non-aqueous early liquid secondary battery (referred to as A2) was prepared by the same method as in Example 1, except that the addition was carried out in the high-voltage non-aqueous electrolyte; 0.1 wt% of the mass content of the agent I was carried out. Example 3

A high-voltage non-aqueous liquid secondary battery (referred to as A3) was prepared by the same method as in Example 1, except that the addition was carried out in the high-voltage non-aqueous electrolyte;

Wt% o Example 4

A high-voltage non-aqueous IL-dissolving secondary battery (referred to as A4) was prepared by the same method as in Example 1, except that the high-voltage non-aqueous electrolyte solution was further added with a film: 1 wt% of film formation: Auxiliary vinylene carbonate (VC). Example 5

High voltage non-aqueous system was prepared by the same method as in Example 1.

(Represented as A5), except that the non-aqueous solvent of the high-voltage non-aqueous electrolyte is a mixed solvent of acid vinyl ester (EC) and diethyl carbonate (DEC) in a volume ratio of 1:1. Example 6 A high-voltage non-aqueous electrolyte secondary battery (referred to as A6) was prepared by the same method as in Example 1, except that the non-aqueous solvent of the high-voltage non-aqueous electrolyte was a vinyl carbonate having a volume ratio of 1:1. A mixed solvent of (EC) and ethyl methyl carbonate (EMC). Examples 7 to 12

o _L o

J ··■·-"

Rl I! i! 2 The additive for the high-voltage non-aqueous electrolyte has a structural formula of 0 0 , wherein R1 is (CF ₃ ) ₂ CHO-, R ₂ is (CF ₃ ) ₂ CHO-, and a high-voltage non-aqueous system is prepared. LiBF _{4 was} used as the lithium salt in the electrolyte, and a layered high-voltage lithium-rich manganese-based oxide was used as the positive electrode active material in the preparation of the positive and negative electrodes. The other steps were the same as in Examples 1 to 6, to obtain a high-voltage non-aqueous electrolysis. The liquid secondary battery is sequentially referred to as A7 to 12. Examples 13 to 18

In addition to the additive for high-voltage non-aqueous electrolytes,

In the same manner as in Examples 1 to 6, except that R1 was -C ₂ H ₅ and R ₂ was CF ₃ CH ₂ 0-, a high-voltage nonaqueous electrolyte secondary battery was obtained, which was sequentially referred to as A13-18. Example 19~24

In addition to the additive used in high voltage nonaqueous electrolytes

O 0

θ

S - S

1 2

ό ό

Wherein R1 is -C¾, R2 is (CF ₃₎ ₂ CHO-, the preparation in the positive, the negative electrode using lithium titanate (Li ₄ Ti ₅ 0 ₁₂₎ as an anode active material, other sequentially same as in Example 1~6 A high-voltage non-aqueous electrolyte secondary battery was produced, which was sequentially referred to as A19 to 24. Example 25~30

The structure of the additive other than the high voltage electroless electrolyte is P Li® p

s ^Ν , , , ' s .,

Rl ' !i W 2

O O ,

Wherein R1 is -C ₄ H ₉ and R ₂ is -C ₂ F ₅ , and in the preparation of the high-voltage non-aqueous electrolyte, LiBF _{4 is} used as the lithium salt, and the others are sequentially the same as in Examples 1 to 6, thereby producing a high voltage non- The aqueous electrolyte secondary battery is sequentially referred to as A25 to 30. Examples 31 to 36

In addition to the additive for high-voltage non-aqueous electrolytes,

In the case where R1 is -F, R2 is -C ₂ F ₅ , and the negative electrode active material used is metal lithium, the other steps are the same as in the first to sixth embodiments, and a high-voltage non-aqueous electrolyte secondary battery is obtained. For A31~36o Comparative Example 1~36

High-voltage non-aqueous electrolyte secondary batteries (referred to as B1 to 36) were prepared by the same methods as in Examples 1 to 36, respectively, in which the difference was in the high-voltage non-aqueous electrolyte of the comparative example, and Example 1 was not added correspondingly. An additive for a high voltage non-aqueous electrolyte in 36. Test example 1~36

The A1~A36 batteries prepared in Examples 1 to 36 and the B1 to B36 batteries prepared in Comparative Examples 1 to 36 were subjected to a charge and discharge cycle test using an automatic charge and discharge apparatus at a test temperature of 25 ° C; wherein, charging and discharging were controlled. The current density is 0.05 mA/cm ² , the charge cut-off voltage at the first charge is 5.1 V, the charge cut-off voltage at the subsequent charge is 4.9 V, the discharge cut-off voltage is 3 V, and the cycle charge and discharge is 100 times.

Coulombic efficiency of A1 battery and B1 battery varies with cycle times at a test temperature of 25 °C As shown in Figure 2, the results show that the A1 battery is equivalent to the charge and discharge capacity of the B1 battery (conventional commercial battery) at room temperature, and the subsequent cycle efficiency of the A1 battery is higher than that of the B1 battery, indicating that the A1 battery is increased with the number of battery cycles. The degree of capacity attenuation is smaller than that of the B1 battery, and thus the electrolyte and the battery provided by the present invention are excellent in operating characteristics at room temperature, and can be used as an electrolyte of a high voltage battery such as a battery using LiNi sMn^O as a positive electrode active material.

At the test temperature of 25 °C, the discharge capacity of the A2~A36 battery and the B2~B36 battery after 100 cycles of cycling and the coulombic efficiency after 30 weeks of cycling were recorded as C1~C35 respectively. The specific results are shown in Table 1. Test example 36~70

The A1 battery and the B1 battery are respectively charged and discharged at 25 °C using an automatic charge and discharge device; wherein, the current density during charging and discharging is 0.1 mA/cm ² , and the charging cut-off voltage at the first charging is 5.1 V, subsequent charging The charge cut-off voltage is 4.9V, and the discharge cut-off voltage is 3V. The charge-discharge coulombic efficiency of A1 battery and B1 battery varies with the number of cycles as shown in Fig. 2. Except that the first charge is slightly lower due to the decomposition of the additive, the efficiency is slightly lower. The A1 battery has a higher charge and discharge coulombic efficiency than the B1 battery.

The same batch of batteries was tested for charge and discharge cycles at a test temperature of 55 °C. The current density during charge and discharge was 0.05 mA/cm ² , the charge cut-off voltage was 4.9 V, and the discharge cut-off voltage was 3 V. A1 battery, B1 battery The charge-discharge Coulomb efficiency varies with the number of cycles as shown in Figure 3. The results show that the A1 battery is significantly higher than the B1 battery at 55 °C, except for the first charge due to the decomposition of the additive, which results in a slightly lower Coulomb efficiency. The charge and discharge coulombic efficiency, thus indicating that the electrolyte and the battery provided by the invention exhibit excellent working characteristics in a high temperature environment, the capacity attenuation of the A1 battery is better than that of the B1 battery, and the ratio of the B1 electrolyte and the battery (commercial lithium hexafluorophosphate) Battery) has superior high temperature resistance.

At the test temperature of 55 °C, the discharge capacity of the A2~A36 battery and the B2~B36 battery after 100 cycles of cycling and the coulombic efficiency after 30 weeks of cycling were recorded as C36~C70 respectively. The specific results are shown in Table 1. Table 1 Test Example 1 and Test Example 2 Results (C1 to C70) Comparison of discharge capacity after 100 cycles Cycle Coulombic efficiency after 30 weeks of cycle

The C1 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C2 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series. The C3 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C4 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C5 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C6 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C7 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C8 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C9 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The CIO A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The Cll A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C12 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C13 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C14 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C15 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C16 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C17 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C18 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C19 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C20 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C21 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C22 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C23 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C24 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C25 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C26 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C27 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C28 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C29 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C30 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C31 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C32 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

C33 A series battery capacity is 1.05 times that of B series. A series battery has a coulombic efficiency of 1.01 times that of B series.

The C34 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C35 A series battery capacity is 1.05 times that of the B series. The A series battery has a coulombic efficiency of 1.01 times that of the B series.

The C36 A series battery capacity is 1.20 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C37 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C38 A series battery capacity is 1.26 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C39 A series battery capacity is 1.21 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C40 A series battery capacity is 1.20 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C41 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C42 A series battery capacity is 1.18 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C43 A series battery capacity is 1.22 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series. The C44 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C45 A series battery capacity is 1.21 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C46 A series battery capacity is 1.20 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C47 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C48 A series battery capacity is 1.21 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C49 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C50 A series battery capacity is 1.22 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C51 A series battery capacity is 1.24 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C52 A series battery capacity is 1.23 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C53 A series battery capacity is 1.19 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C54 A series battery capacity is 1.20 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C55 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C56 A series battery capacity is 1.22 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C57 A series battery capacity is 1.21 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C58 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C59 A series battery capacity is 1.20 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C60 A series battery capacity is 1.22 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C61 A series battery capacity is 1.23 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C62 A series battery capacity is 1.19 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C63 A series battery capacity is 1.25 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C64 A series battery capacity is 1.20 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C65 A series battery capacity is 1.23 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C66 A series battery capacity is 1.18 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C67 A series battery capacity is 1.22 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C68 A series battery capacity is 1.23 times that of the B series. The A series battery has a coulombic efficiency of 1.05 times that of the B series.

The C69 A series battery capacity is 1.20 times that of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series.

The C70 A series battery capacity is 1.20 times of the B series. The A series battery has a coulombic efficiency of 1.04 times that of the B series. Finally, the above embodiments are only used to illustrate the technical solution of the present invention, and are not limited thereto; The foregoing embodiments have been described in detail, and those skilled in the art should understand that the technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced. These modifications and substitutions do not depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

Rights request

1. Use of at least one of the compounds represented by the following formula (I) as a high-voltage non-aqueous electrolyte additive;

⁰ ϋ ^φ 9

... s -' , , s, Π )

Rl""'! ! H, R2

o o

In the formula:

R1 is ¥, C1 to C8 carbhydrazyl, C1 to C8 fluoroindenyl or C1 to C8 fluorodecyloxy; and R2 is C1 to C8 fluoroindenyl or C1 to C8 fluorodecyloxy.

The application according to claim 1, wherein the R1 is F, C1~C3 hydrocarbon hydrazino, CF ₃ CH ₂ 0- or (CF ₃ ) ₂ CHO-, and the R ₂ is C1~ C4 perfluorodecyl, CF ₃ CH ₂ 0- or (CF ₃ ) ₂ CHO-.

A high-voltage nonaqueous electrolytic solution comprising a lithium salt, a nonaqueous solvent in which the lithium salt is dissolved, and an additive selected from the compound represented by the general formula (I) according to claim 1. At least one of the additives, and the additive is contained in the high-voltage non-aqueous electrolyte in a mass percentage of 0.05 to 10%.

The high-voltage non-aqueous electrolyte according to claim 3, wherein the additive is contained in the high-voltage nonaqueous electrolytic solution in an amount of 0.5 to 5% by mass.

The high-voltage non-aqueous electrolyte according to claim 3, wherein the lithium salt is selected from the group consisting of LiPF ₆ , LiBF ₄ , LiAsF ₆ , CF ₃ S0 ₃ Li, Li[N ( FS0 ₂ ) ₂ ] One or more of Li[N ( CF ₃ S0 ₂ ) ₂ ], Li[N ( C ₂ F ₅ S0 ₂ ) ₂ ], Li[C ( C ₂ F ₅ S0 ₂ ) ₃ ].

The high-voltage nonaqueous electrolytic solution according to claim 5, wherein a molar concentration of the lithium salt in the high-voltage nonaqueous electrolytic solution is 0.3 to 3 mol/L.

The high-voltage non-aqueous electrolyte according to claim 3, wherein the non-aqueous solvent is one or more selected from the group consisting of carbonates, carboxylates, ethers, sulfones, and ketones.

The high-voltage nonaqueous electrolytic solution according to claim Ί, wherein the carbonate is one or more selected from the group consisting of C2 to C5 cyclic carbonates and C3 to C7 chain carbonates.

9. The high voltage non-aqueous electrolyte according to claim 8, wherein The C2 to C5 cyclic carbonate is selected from the group consisting of ethylene carbonate or propylene carbonate, and the C3 to C7 chain carbonate is selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate.

The high-voltage nonaqueous electrolytic solution according to claim 9, wherein the nonaqueous solvent is a mixed solvent of a C2 to C5 cyclic carbonate and a C3 to C7 chain carbonate, and the mixed solvent The volume ratio of the cyclic carbonate to the chain carbonate is 1:9 to 9:1.

The high-voltage non-aqueous electrolyte according to claim 3, further comprising an auxiliary agent selected from the group consisting of a film forming aid, a conductive auxiliary agent, a flame retardant auxiliary, and an over-reliance One or more of a agent, a stabilizer, and a multifunctional agent.

The high-voltage non-aqueous electrolyte according to claim 11, wherein the film-forming auxiliary agent is selected from the group consisting of vinylene carbonate, vinyl fluorocarbonate, vinyl sulfite, and propylene sulfite. One or more of dimethyl sulfite, diethyl sulfite, dimethyl sulfoxide.

The high-voltage non-aqueous electrolyte according to claim 11, wherein the auxiliary agent has a mass percentage of 0.01 to 5% in the high-voltage nonaqueous electrolytic solution.

A high-voltage non-aqueous electrolyte secondary battery, comprising: a positive electrode, a negative electrode, and the high-voltage non-aqueous electrolyte according to any one of claims 3 to 13, wherein the positive electrode has reversible deintercalation lithium A positive electrode active material of ions having a negative electrode active material capable of reversibly deintercalating lithium ions.

The high-voltage non-aqueous electrolyte secondary battery according to claim 14, wherein the positive electrode active material is selected from a layered lithium manganese-based oxide, a doped lithium manganese oxide, or a surface modification. One or more of lithium manganese oxides.

The high-voltage non-aqueous electrolyte secondary battery according to claim 15, wherein the positive electrode active material is selected from the group consisting of a layered high-voltage lithium-rich manganese-based positive electrode material and a spinel-shaped lithium nickel manganese oxide. (LiNi sMn^C^ ) or LiNio. ₅ Mn _L 50 coated with a surface modification layer of A1 ₂ 0 ₃ , MgO or Zr0 ₂

The high voltage nonaqueous electrolyte secondary battery according to claim 14, wherein the anode active material is selected from the group consisting of metal lithium, natural graphite, artificial graphite, hard carbon, soft carbon, Li-Sn alloy, Li-Sn-0 alloy, Sn, SnO, SnO ₂ , spinel-structured lithiated Ti0 ₂ , Li ₄ Ti ₅ 0 ₁₂ , Li-Al alloy, silicon, Li-Si alloy, silicon-based composite material Or a variety.

18. The high voltage nonaqueous electrolyte secondary battery according to claim 17, wherein The negative active material is selected from the group consisting of artificial graphite, Li ₄ Ti ₅ 0 ₁₂ or metallic lithium.

19. A method of preparing a high voltage nonaqueous electrolyte secondary battery, comprising:

Preparing a positive electrode and a negative electrode using a positive active material and a negative active material, respectively;

Dissolving at least one of the lithium salt and the compound represented by the formula (I) according to claim 1 in a nonaqueous solvent to obtain a nonaqueous electrolytic solution;

The preparation method according to claim 19, further comprising: charging the high-voltage non-aqueous electrolyte secondary battery for the first time, and controlling the charge cut-off voltage at the time of the first charge to be at least 5.1V.

A high voltage nonaqueous electrolyte secondary battery, which is produced by the production method according to claim 20.

The method of using a high voltage nonaqueous electrolyte secondary battery according to claim 14, comprising: charging the high voltage nonaqueous electrolyte secondary battery for the first time, and controlling the charging cutoff at the time of the first charging The voltage is at least 5.1V.

The method according to claim 22, wherein the current density at the time of the first charging is controlled to be 0.01 to 10 mA/cm ² .

The method according to claim 22, wherein the high-voltage non-aqueous electrolyte secondary battery is subsequently charged, and the charge-off voltage for controlling subsequent charging is 4.7 to 4.9 V, and the discharge cut-off voltage is 3.0 to 3.5V.

25. A method of improving the performance of a high voltage nonaqueous electrolyte secondary battery according to claim 14, wherein the high voltage nonaqueous electrolyte secondary battery is charged for the first time, and charging is controlled for the first charge. The cutoff voltage is at least 5.1V.

26. The method according to claim 25, wherein the current density at the time of the first charging is controlled to be 0.01 to 10 mA/cm<^2> .