Electrolyte, electrochemical device, and electronic device

Abstract

To provide an electrolyte that is highly effective in improving the stability of positive and negative electrode interface protective films.SOLUTION: An electrolyte, an electrochemical device, and an electronic device are disclosed. The electrolyte includes lithium tetrafluoroborate and a compound of Chemical Formula I, and a mass percentage A of the lithium tetrafluoroborate satisfies 0.1%≤A≤2%, and a mass percentage B of the compound of Chemical Formula I satisfies 0.01%≤B≤20%. The lithium tetrafluoroborate reacts with the compound of Chemical Formula I to form a passivation film containing organic and inorganic components and enriched in at least one of B, P, and F. The passivation film is thin and robust, and its presence at the positive electrode interface and / or negative electrode interface effectively enhances the stability of the corresponding electrode piece interface, thereby improving the low-temperature resistance and low-temperature discharge performance of the electrochemical device.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This application relates to the technical field of electrochemical devices, and more particularly to electrolytes, electrochemical devices, and electronic devices. [Background technology]

[0002] Electrochemical devices have advantages such as high energy storage density, high open-circuit voltage, low self-discharge rate, long cycle life, and good safety, and are widely used in various fields such as portable energy storage, electronic devices, and electric vehicles. However, there are also increasing demands for the overall performance of electrochemical devices, such as high energy density and good high-temperature storage and cycle performance. Here, improving the composition of the electrolyte can improve the stability of the protective film formed at the positive and negative electrode interfaces, and further improve the high-temperature and low-temperature performance of the electrochemical device. However, in the related art, the effect of the electrolyte on improving the stability of the protective film at the positive and negative electrode interfaces is still insufficient, and therefore, the composition of the electrolyte needs to be optimized. Summary of the Invention

[0003] The embodiments of the present application provide an electrolyte, an electrochemical device, and an electronic device that can solve the problem of low stability of the electrolyte relative to the protective film at the interface between the positive and negative electrodes.

[0004] In a first aspect, examples of the present application include lithium tetrafluoroborate and a compound of formula I:

[0005] [ka] wherein R in the compound of formula I is a C2-C6 alkyl group which is unsubstituted or substituted with Ra, a C2-C6 alkenyl group which is unsubstituted or substituted with Ra, a C2-C6 alkynyl group which is unsubstituted or substituted with Ra, a C2-C6 nitrogen-containing heteroaromatic group which is unsubstituted or substituted with Ra, or a C6-C 12aromatic groups, and the substituents Ra of each group are each independently selected from fluorine or a C1-C6 fluorinated alkyl group; The present invention provides an electrolyte solution characterized in that, based on the total mass of the non-aqueous electrolyte solution, the mass percentage of the lithium tetrafluoroborate is A and the mass percentage of the compound of formula I is B, where 0.1%≦A≦2% and 0.01%≦B≦20%. By including the compound of formula I and lithium tetrafluoroborate in the electrolyte solution and controlling the mass percentages of the compound of formula I and lithium tetrafluoroborate within the ranges of the present application, the stability of the electrode piece interface can be effectively increased, the resistance of the electrochemical device can be improved, and the low-temperature discharge performance of the electrochemical device can be improved.

[0006] In an exemplary embodiment, the electrolyte satisfies at least one of the following conditions: (1) 0.2%≦A≦1.5%; and (2) 2.0%≦B≦10%.

[0007] In an exemplary embodiment, 15≦B / A≦70. By selecting the contents of both lithium tetrafluoroborate and the compound of formula I to satisfy the above range, the synergistic effect of the two compounds, lithium tetrafluoroborate and the compound of formula I, is apparent, which can improve the interface resistance between the positive and negative electrodes, form a thin passivation film (passivation layer), and effectively improve the ionic conductivity at the interface between the pole pieces.

[0008] In certain exemplary embodiments, the compound of formula I above is

[0009] [ka] It contains at least one of the following.

[0010] By selecting the compound of formula I, the compound of formula I can form a positive electrode interfacial passivation film and / or a negative electrode interfacial passivation film of a lithium-containing inorganic compound rich in S and F elements at the electrode interface, thereby increasing the stability of the positive and negative electrode interfaces, improving the resistance of the electrochemical device, increasing the ionic conductivity, and further improving the low-temperature discharge performance of the electrochemical device.

[0011] In certain illustrative embodiments, the electrolyte further comprises a compound of Formula II, wherein the compound of Formula II is:

[0012] [ka] It contains at least one of the following.

[0013] In one illustrative embodiment, the mass percentage of the compound of formula II, based on the total mass of the electrolyte, is C, where 0.1%≦C≦20%. The compound of formula II is a carboxylic acid ester compound, and has a low viscosity, a low melting point, and a high dielectric constant. By controlling the mass percentage of the compound of formula II in the electrolyte within the above range, when used as a co-solvent with the compound of formula I, the ionic conductivity of the electrolyte at low temperatures can be increased, thereby further improving the low-temperature performance of the electrochemical device.

[0014] In one illustrative embodiment, the electrolyte further comprises a fluorinated carbonate, the fluorinated carbonate comprising at least one of fluoroethylene carbonate, bis(fluoromethyl)carbonate, and 3,3,3-trifluoropropylene carbonate, and the mass percentage of the fluorinated carbonate, based on the total mass of the electrolyte, is F, where 0.01%≦F≦5% and 0.005≦F / (A+B)≦0.5. By selecting the mass percentage of the fluorinated carbonate within the above ranges, the fluorinated carbonate can further improve the interfacial resistance of the negative electrode and enhance the low-temperature discharge performance of the electrochemical device. In addition, the fluorinated carbonate acts in conjunction with the compound of Formula I and lithium tetrafluoroborate to enhance the dissociation degree of lithium tetrafluoroborate based on the high dielectric constant of the fluorinated carbonate and the compound of Formula I, thereby improving the low-temperature discharge performance of the electrochemical device.

[0015] In one illustrative embodiment, the electrolyte further comprises a cyclic sulfur-oxygen double bond compound, including at least one of 1,3-propane sultone, ethylene sulfate, and methylene methanedisulfonate, wherein the mass percentage of the cyclic sulfur-oxygen double bond compound, based on the total mass of the electrolyte, is S, where 0.01%≦S≦5.0% and 0.003≦S / (A+B)≦0.5. By selecting the mass percentage of the cyclic sulfur-oxygen double bond compound within the above ranges, the cyclic sulfur-oxygen double bond compound can further enrich the interface components between the positive and negative electrodes during charge and discharge and increase the density of the passivation film. Furthermore, the cyclic sulfur-oxygen double bond compound can cooperate with the compound of Formula I and lithium tetrafluoroborate to improve the ionic conductivity of the electrolyte at low temperatures based on the solvation structure of the cyclic sulfur-oxygen double bond compound and the compound of Formula I with respect to lithium ions.

[0016] In a second aspect, the present application provides an electrochemical device comprising the above-described electrolyte.

[0017] In a third aspect, the present application provides an electronic device comprising the electrochemical device described above.

[0018] According to the electrolyte, electrochemical device, and electronic device of the embodiments of the present application, lithium tetrafluoroborate and a compound of formula I are added to the electrolyte, and the mass percentage A of lithium tetrafluoroborate is selected to be 0.1%≦A≦2%, and the mass percentage B of the compound of formula I is selected to be 0.01%≦B≦20%, so that the lithium tetrafluoroborate can react with the compound of formula I to form a passivation film containing organic and inorganic components and rich in at least one of the elements B, P, and F. This passivation film is thin and durable, and exists at the positive electrode interface and / or negative electrode interface, thereby effectively increasing the stability of the electrode piece interface, improving the resistance of the electrochemical device, and improving the low-temperature discharge performance of the electrochemical device.

[0019] The passive film in this application also refers to a protective film layer formed on the interface between the positive electrode and / or negative electrode. DETAILED DESCRIPTION OF THE INVENTION

[0020] The technical solutions in the embodiments of the present application will be described clearly and completely below, but it should be clear that the described embodiments are only some embodiments of the present application, not all of the embodiments, and all other embodiments that those skilled in the art can obtain based on the present application are also within the scope of protection of the present application.

[0021] In the following description, the present application will be interpreted as taking a lithium ion battery as an example of an electrochemical device, but it should be noted that the electrochemical device of the present application is not limited to a lithium ion battery.

[0022] In a first aspect, the present application provides an electrolyte solution for use in an electrochemical device, the electrolyte solution comprising lithium tetrafluoroborate and a compound of Formula I, wherein, based on the total mass of the electrolyte solution, a mass percentage A of the lithium tetrafluoroborate satisfies 0.1%≦A≦2%, and a mass percentage B of the compound of Formula I satisfies 0.01%≦B≦20%, and the electrolyte solution is capable of forming a thin and robust passivation film at the interfaces between positive and negative electrodes, thereby improving the positive and negative electrode interfacial resistance and low-temperature discharge performance.

[0023] The electrolyte solution of the present application comprises a compound of formula I:

[0024] [ka] is. wherein R in the compound of formula I is a C2-C6 alkyl group which is unsubstituted or substituted with Ra, a C2-C6 alkenyl group which is unsubstituted or substituted with Ra, a C2-C6 alkynyl group which is unsubstituted or substituted with Ra, a C2-C6 nitrogen-containing heteroaromatic group which is unsubstituted or substituted with Ra, or a C6-C 12 The substituents Ra of each group are independently selected from fluorine or a C1 to C6 fluorinated alkyl group.

[0025] In the examples of the present application, by adding the compound of formula I to the electrolyte, the compound of formula I can form a positive electrode interfacial passivation film and / or a negative electrode interfacial passivation film made of a lithium-containing inorganic compound rich in S and F elements at the electrode interface, thereby increasing the stability of the positive and negative electrode interfaces, improving the resistance of the electrochemical device, increasing the ionic conductivity, and further improving the low-temperature discharge performance of the electrochemical device.

[0026] The mass percentage of the compound of Formula I, based on the mass of the electrolyte, is B, and in some embodiments, 0.01%≦B≦20%. In some embodiments, 1.0%≦B≦15%. In some embodiments, 2.0%≦B≦10%. In some embodiments, 2.0%≦B≦5%, and in some embodiments, 0.05%≦B≦10%. In some embodiments, the value of B is 0.01%, 0.03%, 0.05%, 0.07%, 1.0%, 8.0%, 10.0%, 13.0%, 18%, 20%, or a value within a range consisting of any two of these values. By selecting B within the above range, the content of the compound of Formula I is optimized, promoting uniform deposition of compounds containing elements such as S and F at the positive electrode interface, while simultaneously increasing the ionic conductivity at the positive electrode interface and improving the positive electrode interfacial resistance. If B exceeds the upper limit of 20%, the thickness of the passive film formed at the positive electrode interface increases, the ionic conductivity decreases, and the resistance deteriorates, thereby reducing the ionic conductivity at the positive electrode interface. If B is less than the lower limit of 0.01%, it becomes difficult to exert the effect of improving the interfacial resistance.

[0027] In certain embodiments, the compound of Formula I is

[0028] [ka] It contains at least one of the following.

[0029] The electrolyte further comprises lithium tetrafluoroborate, which can react with the compound of formula I to form a passivation film comprising an organic component and an inorganic component and rich in at least one of B, P, and F. The passivation film is thin and robust, and exists at the positive electrode interface or the negative electrode interface, which can effectively increase the stability of the electrode piece interface, improve the resistance of the electrochemical device, and improve the low-temperature discharge performance of the electrochemical device.

[0030] The mass percentage of lithium tetrafluoroborate, based on the mass of the electrolyte, is A, and in some embodiments, A is 0.1%≦A≦2%. In some embodiments, A is 0.1%, 0.2%, 0.3%, 0.5%, 0.7%, 1.0%, 1.2%, 1.5%, 1.8%, or 2.0%, or a value within a range consisting of any two of these values. In some embodiments, 0.3%≦A≦2%. In some embodiments, 0.4%≦A≦1.8%. In some embodiments, 0.5%≦A≦2%. In some embodiments, 1.8%≦A≦2%. In the present application, A satisfies the above range, and further optimizing the content of lithium tetrafluoroborate can satisfy the above-mentioned range, and the lithium tetrafluoroborate and the compound of Formula I can jointly optimize the morphology of the positive and negative electrode interfaces, while reducing the increase in positive and negative electrode resistance due to excessive decomposition of lithium tetrafluoroborate itself. If A exceeds the upper limit of 10%, lithium tetrafluoroborate cannot be completely ionized, and the conductivity of the electrolyte decreases. If A falls below the lower limit of 0.3%, the content of B in the film-forming components becomes insufficient, making it difficult to exert the effect of improving the interface.

[0031] In some embodiments, 15≦B / A≦70. In some embodiments, 15≦B / A≦65.0. In some embodiments, 20.0≦B / A≦60.0. In some embodiments, 25.0≦B / A≦60.0. In some embodiments, 20.0≦B / A≦65.0. In some embodiments, the value of B / A is 0.005, 5.0, 15.0, 26.8, 31.8, 41.0, 52.7, 73.4, 84.5, or 95.0, or a value within a range consisting of any two of these values. In the present application, by controlling the value of B / A within the above range, the synergistic effect of the two compounds, lithium tetrafluoroborate and the compound of formula I, is apparent, which can improve the interface resistance of the positive and negative electrodes, form a thin passivation film, and effectively improve the ionic conductivity at the electrode piece interface.

[0032] In one embodiment, the electrolyte further comprises a compound of formula II, wherein the compound of formula II is:

[0033] [ka] It contains at least one of the following.

[0034] In some embodiments, the weight percentage of the compound of Formula II, based on the total weight of the electrolyte, is C, and C satisfies the following: 0.1%≦C≦20%. In some embodiments, 0.1%≦C≦10%. In some embodiments, 0.5%≦C≦15.0%. In some embodiments, 0.5%≦C≦12.0%. In some embodiments, 1.0%≦C≦15.0%. In some embodiments, the value of C is 0.1%, 0.5%, 1.5%, 8.8%, 9.8%, 10.0%, 12.8%, 13.6%, 15.5%, or 20.0%, or a value within a range consisting of any two of these values. The compound of formula II is a carboxylic acid ester compound having a low viscosity, a low melting point, and a high dielectric constant. When the mass percentage of the compound of formula II in the electrolyte is controlled within the above range, the ionic conductivity of the electrolyte at low temperatures can be increased when used as a co-solvent with the compound of formula I, thereby further improving the low-temperature performance of the electrochemical device.

[0035] In one embodiment, the electrolyte comprises a fluorinated carbonate, including at least one of fluoroethylene carbonate, bis(fluoromethyl)carbonate, and 3,3,3-trifluoropropylene carbonate.

[0036] In some embodiments, the weight percentage of the fluorinated carbonate, based on the total weight of the electrolyte, is F, and F satisfies the following: 0.01%≦F≦5.0%. In some embodiments, 0.1%≦F≦5.0%. In some embodiments, 0.5%≦F≦4.0%. In some embodiments, 0.9%≦F≦3.5%. In some embodiments, 0.1%≦F≦3.5%. In some embodiments, 0.9%≦F≦3%. In some embodiments, the value of F is 0.01%, 0.05%, 0.25%, 1.0%, 2.0%, 3.0%, 3.1%, 3.8%, 4.5%, or 5.0%, or a value within a range consisting of any two of these values. Fluorinated carbonate has good reducing performance, and by selecting the content of fluorinated carbonate within the above range, the fluorinated carbonate can further improve the interface resistance of the negative electrode and enhance the low-temperature discharge performance of the electrochemical device.In addition, the fluorinated carbonate can act in conjunction with the compound of formula I and lithium tetrafluoroborate, and based on the high dielectric constant of the fluorinated carbonate and the compound of formula I, increase the dissociation degree of lithium tetrafluoroborate, thereby improving the low-temperature discharge performance of the electrochemical device.

[0037] In some embodiments, F, A, and B satisfy the following condition: 0.005≦F / (A+B)≦0.5. In some embodiments, 0.01≦F / (A+B)≦0.4. In some embodiments, 0.05≦F / (A+B)≦0.3. In some embodiments, 0.06≦F / (A+B)≦0.2. In some embodiments, 0.06≦F / (A+B)≦0.2. In some embodiments, the value of F / (A+B) is 0.005, 0.007, 0.03, 0.09, 0.12, 0.15, 0.2, 0.25, 0.45, 0.5, or a value within a range formed by any two of these values. By adjusting the fluorinated carbonate, lithium tetrafluoroborate, and compound of formula I in the electrolyte solution so that the range of the above conditional formula is satisfied, the elements S, B, F, P, etc. contained in the passivation film formed at the electrode interface can be distributed more uniformly, further increasing the ionic conductivity of the electrochemical device and making the positive and negative electrode interfaces more stable.

[0038] In some embodiments, the electrolyte further comprises a cyclic sulfur-oxygen double bond compound comprising at least one of 1,3-propane sultone, ethylene sulfate, and methylene methanedisulfonate.

[0039] In some embodiments, the mass percentage of the cyclic sulfur-oxygen double bond compound, S, based on the total mass of the electrolyte satisfies the following condition: 0.01%≦S≦5.0%. In some embodiments, 0.2%≦S≦5.0%. In some embodiments, 0.4%≦S≦4.5%. In some embodiments, 0.3%≦S≦4.5%. In some embodiments, 0.2%≦S≦3.0%. In some embodiments, 3.0%≦S≦5.0%. In some embodiments, the value of S is 0.01%, 0.15%, 0.75%, 2.5%, 2.8%, 3.0%, 3.6%, 4.1%, 4.5%, or 5.0%, or a value within a range consisting of any two of these values. By selecting the cyclic sulfur-oxygen double bond compound within the above range, the cyclic sulfur-oxygen double bond compound can further enrich the components at the interface between the positive and negative electrodes during charge and discharge and increase the density of the passivation film. Furthermore, the cyclic sulfur-oxygen double bond compound can work in cooperation with the compound of Formula I and lithium tetrafluoroborate to improve the ionic conductivity of the electrolyte at low temperatures based on the solvation structure of the cyclic sulfur-oxygen double bond compound and the compound of Formula I with respect to lithium ions.

[0040] In some embodiments, S, A, and B satisfy the following condition: 0.003≦S / (A+B)≦0.5. In some embodiments, 0.005≦S / (A+B)≦0.4. In some embodiments, 0.01≦S / (A+B)≦0.3. In some embodiments, 0.01≦S / (A+B)≦0.2. In some embodiments, 0.008≦S / (A+B)≦0.2. In some embodiments, the value of S / (A+B) is 0.003, 0.004, 0.008, 0.01, 0.05, 0.3, 0.35, or 0.5, or a value within a range consisting of any two of these values. By adjusting the cyclic sulfur-oxygen double bond compound, lithium tetrafluoroborate, and the compound of Formula I in the electrolyte to satisfy the above-mentioned conditional formula range, the lithium ion mobility can be increased and the conductivity of the electrolyte can be improved based on the solvation structure formed by the cyclic sulfur-oxygen double bond compound, the compound of Formula I, and lithium tetrafluoroborate jointly, thereby improving the low-temperature discharge performance of the electrochemical device.

[0041] The electrolyte solution further contains a lithium salt. The type of lithium salt in the electrolyte solution is not particularly limited as long as it can achieve the objectives of the present application. For example, the electrolyte solution may contain at least one of lithium hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF), lithium difluorophosphate (LiPOF), lithium bistrifluoromethanesulfonylimide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bisoxalate borate (LiBOB), and lithium difluorooxalate borate (LiDFOB). Based on the total mass of the electrolyte solution, the mass percentage of the lithium salt may be 8% to 15%, for example, 8%, 9%, 10%, 11%, 12.5%, 13%, or 15%, or a range consisting of any two of these values.

[0042] The electrolyte may further contain a non-aqueous solvent. The present application does not particularly limit the type of non-aqueous solvent in the electrolyte, as long as it can achieve the objectives of the present application. For example, the electrolyte may contain at least one of a carbonate compound, a carboxylic acid ester compound, an ether compound, and other organic solvents. The carbonate compound may include at least one of a chain carbonate compound and a cyclic carbonate compound. The chain carbonate compound may include at least one of dimethyl carbonate, propylene carbonate, ethylene carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, and methyl ethyl carbonate. The cyclic carbonate compound may include at least one of butylene carbonate and vinyl ethylene carbonate. The carboxylic acid ester compound may include at least one of methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, γ-butyrolactone, decanolactone, valerolactone, and caprolactone. The ether compound may include at least one of ethylene glycol dimethyl ether, dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1-ethoxy-1-methoxyethane, 2-methyltetrahydrofuran, and tetrahydrofuran. The other organic solvent may include at least one of dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, and trioctyl phosphate.

[0043] In a second aspect, the present application provides an electrochemical device comprising the above-described electrolyte, and further comprising a positive electrode, a negative electrode, and a separator.

[0044] The present application does not particularly limit the materials, structures, and processing methods of the positive electrode, negative electrode, and separator of the electrochemical device, and any positive electrode, negative electrode, and separator that can be used in the relevant technical field can be applied to the present application.

[0045] I Positive electrode The positive electrode of the electrochemical device of the present application includes a positive electrode current collector and a positive electrode active material layer provided on the surface of the positive electrode current collector. The positive electrode active material layer may be applied to one or both surfaces of the positive electrode current collector.

[0046] The positive electrode material layers provided on the same side of the positive electrode current collector may be single or multiple, and each layer of the multiple positive electrode material layers may contain the same or different positive electrode active materials. The positive electrode active material used in the electrochemical device may include at least one of lithium nickel cobalt manganese oxide (e.g., NCM811, NCM622, NCM523, NCM111), lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium-rich manganese-based material, lithium cobalt oxide (LiCoO), lithium manganese oxide, lithium iron manganese phosphate, and lithium titanate.

[0047] The positive electrode layer of the present application further includes a conductive agent and a binder. The conductive agent and binder in the positive electrode layer are not particularly limited as long as they can achieve the objectives of the present application. For example, the conductive agent may include at least one of conductive carbon black, carbon nanotubes (CNTs), carbon fiber, flake graphite, graphene, a metal material, and a conductive polymer, but is not limited thereto. The conductive carbon black may include, but is not limited to, Super P, acetylene black, or Ketjen black. The carbon nanotubes may include, but are not limited to, single-walled carbon nanotubes and / or multi-walled carbon nanotubes. The carbon fiber may include, but is not limited to, vapor-grown carbon fiber (VGCF) and / or nanocarbon fiber. The metal material may include metal powder and / or metal fiber. Specifically, the metal may include, but is not limited to, at least one of copper, nickel, aluminum, and silver. The conductive polymer may include at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene, and polypyrrole, but is not limited to these. The binder may include at least one of polyacrylic acid ester, polyimide, polyamide, polyamideimide, polyvinylidene fluoride, styrene-butadiene copolymer (styrene-butadiene rubber, SBR), sodium alginate, polyvinyl alcohol, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethyl cellulose (CMC-Na), potassium carboxymethyl cellulose, sodium hydroxymethyl cellulose, and potassium hydroxymethyl cellulose, but is not limited to these. The present application does not particularly limit the mass ratio of the positive electrode active material, conductive agent, and binder in the positive electrode layer, and those skilled in the art can select the mass ratio according to actual needs as long as the objectives of the present application can be achieved.

[0048] The present application is not particularly limited to the positive electrode current collector, and any material may be used as long as it can achieve the objectives of the present application. For example, the positive electrode current collector may include aluminum foil, aluminum alloy foil, or a composite current collector (e.g., an aluminum-carbon composite current collector). The present application is not particularly limited to the thickness of the positive electrode current collector, and any material may be used as long as it can achieve the objectives of the present application. For example, the thickness of the positive electrode current collector is 5 μm to 20 μm, and preferably 6 μm to 18 μm. The present application is not particularly limited to the thickness of the positive electrode material layer, and any material may be used as long as it can achieve the objectives of the present application. For example, the thickness of the positive electrode material layer on one side is 30 μm to 120 μm.

[0049] Optionally, the positive electrode may further include a conductive layer, which is located between the positive electrode current collector and the positive electrode material layer. The present application does not particularly limit the composition of the conductive layer, and may be a conductive layer commonly used in the art. The conductive layer includes a conductive agent and a binder. The present application does not particularly limit the conductive agent and binder in the conductive layer, and may be at least one of the above conductive agents and binders. The present application does not particularly limit the mass ratio of the conductive agent and binder in the conductive layer, and those skilled in the art can select it according to actual needs as long as the objectives of the present application can be achieved.

[0050] The electrochemical device of the present application further includes a negative electrode including a negative electrode current collector and a negative electrode material layer provided on at least one surface of the negative electrode current collector. The phrase "a negative electrode material layer provided on at least one surface of the negative electrode current collector" refers to the negative electrode material layer being provided on one surface of the negative electrode current collector in the thickness direction, or on two surfaces of the negative electrode current collector in the thickness direction. The "surface" here may refer to the entire area of ​​the negative electrode current collector or a partial area of ​​the negative electrode current collector. The present application is not particularly limited, and any material may be used as long as it can achieve the objectives of the present application. The present application is not particularly limited, and any material may be used as long as it can achieve the objectives of the present application, such as copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a composite current collector.

[0051] The negative electrode material layer of the present application contains a negative electrode active material. There is no particular limitation on the negative electrode active material in the present application, and any material can be used as long as the object of the present application can be achieved. For example, the negative electrode active material may include at least one of natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, SiO x (0.5 < x < 1.6), Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO2, lithium titanate Li4Ti5O with a spinel structure 12 , Li-Al alloy, and metallic lithium. The negative electrode material layer of the present application further contains a binder. There is no particular limitation on the binder in the negative electrode material layer of the present application, and any binder can be used as long as the object of the present application can be achieved. For example, the binder may be at least one of the above-mentioned binders. The negative electrode material layer of the present application further contains a conductive agent. There is no particular limitation on the conductive agent in the negative electrode material layer of the present application, and any conductive agent can be used as long as the object of the present application can be achieved. For example, the conductive agent may be at least one of the above-mentioned conductive agents. There is no particular limitation on the mass ratio of the negative electrode active material, binder, and conductive agent in the negative electrode material layer of the present application, and those skilled in the art can select according to actual needs as long as the object of the present application can be achieved.

[0052] There is no particular limitation on the thickness of the negative electrode current collector in the present application, and any thickness can be used as long as the object of the present application can be achieved. For example, the thickness of the negative electrode current collector is 5 μm to 16 μm. There is no particular limitation on the thickness of the negative electrode material layer in the present application, and any thickness can be used as long as the object of the present application can be achieved. For example, the thickness of the negative electrode material layer on one side is 30 μm to 120 μm.

[0053] Optionally, the negative electrode may include a conductive layer located between the negative electrode current collector and the negative electrode material layer. The present application does not particularly limit the composition of the conductive layer, and it may be a conductive layer commonly used in the art. The conductive layer further includes a conductive agent and a binder. The present application does not particularly limit the conductive agent and binder in the conductive layer, and it may be at least one of the above conductive agents and binders. The present application does not particularly limit the mass ratio of the conductive agent and binder in the conductive layer, and those skilled in the art can select it according to actual needs as long as the objectives of the present application can be achieved. The present application does not particularly limit the thickness of the conductive layer, and it may be any thickness that can achieve the objectives of the present application. For example, the thickness of the conductive layer is 1 μm to 10 μm.

[0054] The electrochemical device of the present application further includes a separator that separates the positive electrode piece from the negative electrode, prevents short circuits within the electrochemical device, allows free passage of electrolyte ions, and does not affect the progress of the electrochemical charge / discharge process. The present application does not limit the separator in any way, as long as it achieves the objectives of the present application. For example, the separator material may include at least one of polyolefins (PO) mainly consisting of polyethylene (PE), polypropylene (PP), polyester (e.g., polyethylene terephthalate (PET) film), cellulose, polyimide (PI), polyamide (PA), polyurethane, and aramid. The separator type may include at least one of woven membrane, nonwoven membrane, microporous membrane, composite membrane, rolled membrane, and spun membrane, but is not limited to these. The present application does not limit the separator thickness in any way, as long as it achieves the objectives of the present application. For example, the separator thickness may be 3 μm to 30 μm.

[0055] In the present application, the separator may include a substrate and a surface treatment layer. The substrate may be a nonwoven fabric or composite membrane having a porous structure, and the material of the substrate may include at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyimide. Optionally, a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, and a polypropylene-polyethylene-polypropylene porous composite membrane may be used. Optionally, the thickness of the base membrane is 3 μm to 25 μm. Optionally, a surface treatment layer may be provided on at least one surface of the substrate, and the surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic material. For example, the inorganic layer contains inorganic particles and a binder. The inorganic particles are not particularly limited, and may include, for example, at least one of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, tin oxide, cerium oxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and barium sulfate. The binder is not particularly limited, and may include, for example, at least one of the binders listed above. The polymer layer contains a polymer. The polymer material may include at least one of polyamide, polyacrylonitrile, acrylic acid ester polymer, polyacrylic acid, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride, and poly(vinylidene fluoride-hexafluoropropylene). Optionally, the surface treatment layer has a thickness of 1 μm to 10 μm.

[0056] The electrochemical device of the present application further includes a packaging bag for containing the positive electrode pieces, separator, negative electrode, and electrolyte, as well as other components known in the art for electrochemical devices, but the present application is not limited to these other components. The present application is not particularly limited to the packaging bag, and any packaging bag known in the art may be used as long as it can achieve the objectives of the present application.

[0057] The present application is not particularly limited to the type of electrochemical device, and can include any device in which an electrochemical reaction occurs. In the present application, electrochemical devices may include, but are not limited to, lithium metal electrochemical devices, lithium ion electrochemical devices (lithium ion batteries), lithium polymer electrochemical devices, and lithium ion polymer electrochemical devices (lithium ion polymer batteries).

[0058] The manufacturing process of the electrochemical device of the present application is well known to those skilled in the art and is not particularly limited. For example, the manufacturing process may include, but is not limited to, the following steps: stacking a positive electrode piece, a separator, and a negative electrode in order, and optionally winding or folding the stacked electrode assembly to obtain a wound electrode assembly, placing the electrode assembly in a packaging bag, injecting an electrolyte, and sealing the bag to obtain an electrochemical device; or stacking a positive electrode piece, a separator, and a negative electrode in order, and then securing the four corners of the entire stacked structure with tape to obtain a stacked electrode assembly, placing the electrode assembly in a packaging bag, injecting an electrolyte, and sealing the bag to obtain an electrochemical device. Furthermore, if necessary, an overcurrent protection element, a conductive plate, etc. can be placed in the packaging bag to prevent pressure buildup and overcharging and discharging within the electrochemical device.

[0059] The present application further provides an electronic device including the electrochemical device according to any of the above embodiments, and therefore the electronic device provided herein has good performance in use.

[0060] The present application is not particularly limited to the type of electronic device, and may be any electronic device known in the art. In some embodiments, the electronic device may include, but is not limited to, a notebook computer, a pen-based computer, a mobile computer, an e-book player, a mobile phone, a mobile facsimile machine, a mobile copier, a mobile printer, a headset-type stereo headphone, a video recorder, an LCD television, a portable vacuum cleaner, a portable CD player, a minidisc, a transceiver, an electronic organizer, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a bicycle, a bicycle, a lighting fixture, a toy, a game console, a watch, a power tool, a flash, a camera, a large-scale household battery, and a lithium-ion capacitor.

[0061] The following describes the fabrication of electrochemical devices based on specific examples, and those skilled in the art should understand that the fabrication methods described herein are merely exemplary, and that any suitable fabrication method is within the scope of the present application.

[0062] Example Hereinafter, the embodiments of the electrochemical device of the present application will be described in more detail with examples and comparative examples using a lithium ion battery as an example. Those skilled in the art should understand that the manufacturing methods described in the present application are merely examples, and that any appropriate manufacturing method is within the scope of the present application. Various tests and evaluations are performed according to the following methods. Unless otherwise specified, "parts" or "%" are based on mass.

[0063] Test Method 1. -10℃ 50% SOC resistance test method At 25°C, discharge a lithium-ion battery at 0.5C to 3.0V, let it rest for 5 minutes, then charge it at 0.5C to 4.5V, and charge it at 4.5V with a constant voltage of 0.025C. Let it rest for 5 minutes, then discharge it at 0.1C to 3.0V, recording the discharged capacity as C1. Charge it at 0.5C to 4.5V, then charge it at a constant voltage of 0.025C at 4.5V, and let it rest for 5 minutes. Then, at -10°C, discharge the lithium-ion battery at 0.1C for 5 hours, recording the battery voltage as V1. Then, discharge it at 1C for 1 second, recording the battery voltage as V2. -10℃ 50%SOC resistance = (V1-V2) / (1C-0.1C1).

[0064] 2. Low-temperature discharge performance test method The lithium-ion battery is placed in a constant temperature environment at 25°C and allowed to stand for 30 minutes to allow the lithium-ion battery to reach a constant temperature of 25°C. It is then charged to 4.5V at a constant current of 0.5C, charged to a current of 0.025C at a constant voltage of 4.5V, and discharged to 3.0V at a constant current of 0.2C. The discharge capacity at 25°C is recorded as C2. It is then charged to 4.5V at a constant current of 0.5C, charged to a current of 0.025C at a constant voltage of 4.5V, and transferred to a constant temperature test box at -10°C. It is allowed to stand for 60 minutes to allow the lithium-ion battery to reach a constant temperature of -10°C. It is then discharged to 3.0V at a constant current of 0.2C. The discharge capacity at -10°C is recorded as C3. -10℃ Low temperature discharge capacity retention rate = C3 / C2×100%.

[0065] 1. Manufacturing of positive electrode pieces The positive electrode active material is LiCoO2, the positive electrode conductive agent is conductive carbon black (Super P), and the positive electrode binder is polyvinylidene fluoride (PVDF, Mw = 7 × 10 6) were mixed in a mass ratio of 97.5:1:1.5, N-methylpyrrolidone (NMP) was added as a solvent, and the mixture was uniformly stirred using a vacuum stirrer to obtain a positive electrode slurry with a solids content of 75 wt%. The positive electrode slurry was uniformly applied to one surface of an aluminum foil positive electrode current collector with a thickness of 10 μm, dried at 85°C, and cold pressed to obtain a positive electrode piece with a 50 μm thick positive electrode material layer applied to one side. The above process was then repeated on the other surface of the aluminum foil to obtain a positive electrode piece with a positive electrode material layer applied to both sides. The aluminum tab of the positive electrode tab was then cut and welded to obtain a positive electrode piece with a size of 74 mm x 851 mm, which was then left to stand. The compaction density of the positive electrode material layer was 4.15 g / cm. 3 is.

[0066] 2. Manufacturing of negative electrode pieces The negative electrode active material is artificial graphite, the negative electrode conductive agent is Super P, and the thickener is carboxymethyl cellulose (CMCNa, Mw=7×10 5 ), and the negative electrode binder styrene butadiene rubber (SBR, Mw=5×10 6 ) were mixed in a mass ratio of 97.5:1:0.5:1, then deionized water was added as a solvent and the mixture was uniformly stirred using a vacuum mixer to obtain a negative electrode slurry with a solids content of 50 wt%. The negative electrode slurry was uniformly applied to one surface of a copper foil negative electrode current collector with a thickness of 8 μm, dried at 85°C, and cold pressed to obtain a negative electrode piece with a 60 μm thick negative electrode material layer applied to one side. The above process was then repeated on the other surface of the copper foil to obtain a negative electrode piece with a negative electrode material layer applied to both sides. After further cutting and welding of the nickel tab of the negative electrode tab, a negative electrode piece with a size of 76 mm x 867 mm was obtained and left to stand, with the compaction density of the negative electrode material layer being 1.75 g / cm. 3 is.

[0067] 3. Electrolyte production In an argon atmosphere glove box with a water content of less than 10 ppm, dimethyl carbonate, propylene carbonate, and ethylene carbonate are mixed in a mass ratio of 60:30:10 to obtain a base solvent, and then lithium tetrafluoroborate, the compound of Formula I, and lithium hexafluorophosphate (LiPF) are dissolved in the base solvent to obtain an electrolyte solution, where the mass percentage of LiPF is 12.5% ​​based on the total mass of the electrolyte solution. The weight percentages of lithium tetrafluoroborate and the weight percentages of the compound of formula I are as shown in Table 1, with the remainder being the base solvent.

[0068] 4. Separator A 15 μm thick polyethylene (PE) porous membrane is used.

[0069] 5. Lithium-ion battery manufacturing The separator, positive electrode piece, separator, and negative electrode piece prepared above are stacked in this order and wound to obtain a wound electrode assembly. The electrode assembly is placed in an aluminum laminate film packaging bag, dried, and then an electrolyte is injected. The assembly is then vacuum sealed, left to stand, chemically formed (charged to 3.5 V at a constant current of 0.2 C, then charged to 3.9 V at a constant current of 1 C), capacity measured, degassed, and trimmed to obtain a lithium-ion battery.

[0070] Examples 1-2 to 1-17 are the same as Example 1-1, except that in the preparation of the electrolyte solution, the type of compound of formula I, the content B of the compound of formula I, and the content A of lithium tetrafluoroborate were adjusted as shown in Table 1. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0071] Comparative Example 1-2 is the same as Example 1-1, except that lithium tetrafluoroborate is not added to the electrolyte, where the mass percentage of the base solvent changes accordingly and the mass percentage of the lithium salt remains constant.

[0072] Comparative Examples 1-3 to 1-6 are the same as Example 1-1, except that in the preparation of the electrolyte solution, the content B of the compound of formula I and the content A of lithium tetrafluoroborate were adjusted as shown in Table 1. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0073] Examples 2-1 to 2-7 are the same as Examples 1-4, except that the compounds of formula II were added in the preparation of the electrolyte solutions as shown in Table 2. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0074] Examples 3-1 to 3-6 are the same as Examples 1-4, except that fluorinated carbonate was added to the electrolyte solution as shown in Table 3. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0075] Examples 3-7 and 3-8 are the same as Examples 1-4, except that the compound of formula II and the fluorinated carbonate were added to prepare the electrolyte solution as shown in Table 3. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0076] Examples 4-1 to 4-4 are the same as Examples 1-4, except that a cyclic sulfur-oxygen double bond compound was added to the electrolyte solution as shown in Table 4. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0077] Examples 4-5 to 4-6 are the same as Examples 1-4, except that the cyclic sulfur-oxygen double bond compound and the compound of formula II were added to prepare the electrolyte solution as shown in Table 4. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0078] Examples 4-7 and 4-8 are the same as Examples 1-4, except that a cyclic sulfur-oxygen double bond compound and a fluorinated carbonate were added to the electrolyte solution as shown in Table 4. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0079] Examples 4-9 and 4-10 are the same as Examples 1-4, except that the cyclic sulfur-oxygen double bond compound, fluorinated carbonate, and compound of Formula II were added to the electrolyte solution as shown in Table 4. Here, the mass percentage of the base solvent was changed accordingly, and the mass percentage of the lithium salt was unchanged.

[0080] Table 1 shows the manufacturing parameters and performance parameters of Examples 1-1 to 1-17 and Comparative Examples 1-1 to 1-6.

[0081] [Table 1] Note: " / " in Table 1 indicates that there is no corresponding parameter.

[0082] As can be seen from Examples 1-1 to 1-17 and Comparative Examples 1-1 to 1-6 in Table 1, the inclusion of the compound of formula I and lithium tetrafluoroborate in the electrolyte can effectively improve the low-temperature resistance of the electrochemical device, and the compound of formula I and lithium tetrafluoroborate can form a passivation film rich in elements such as B, P, and S at the positive electrode interface, thereby reducing the interface resistance and simultaneously improving the low-temperature discharge performance of the electrochemical device.

[0083] As can be seen from Examples 1-1 to 1-6 and Comparative Examples 1-3 and 1-4, when the mass percentage A of lithium tetrafluoroborate satisfies the range of 0.1%≦A≦2%, the low-temperature resistance performance of the electrochemical device can be effectively improved. When A is below the lower limit of 0.3%, it becomes difficult to exert the effect of improving the interface stability. When A exceeds the upper limit of 10%, lithium tetrafluoroborate cannot be completely ionized, the conductivity of the electrolyte decreases, and in severe cases, the resistance of the lithium ion battery is deteriorated.

[0084] As can be seen from Examples 1-7 to 1-17 and Comparative Examples 1-5 and 1-6, when the mass percentage B of the compound of Formula I satisfies 0.01%≦B≦20%, the low-temperature interfacial resistance performance of the electrochemical device can be effectively improved. Similarly, when B is below the lower limit of 1%, it becomes difficult to exert the interfacial modification effect. When B exceeds the upper limit of 30%, the thickness and bulkiness of the formed passivation film increases, the ionic conductivity decreases, and therefore the resistance of the lithium-ion battery deteriorates.

[0085] As can be seen from Examples 1-1 to 1-17, when A and B satisfy 15≦B / A≦70, the passivation film formed by the compound of Formula I and lithium tetrafluoroborate can improve the conductivity of lithium ions, thereby effectively improving the low-temperature discharge performance of lithium ion batteries.

[0086] The manufacturing parameters and performance parameters of Examples 1-4 and 2-1 to 2-7 are as shown in Table 2.

[0087] [Table 2]

[0088] As can be seen from Examples 1-4, 2-1 to 2-7 in Table 2, by introducing the compound of formula II into the electrolyte and making the content C of the compound of formula II satisfy 0.1%≦C≦20%, the viscosity of the electrolyte can be reduced and at the same time, the dissociation of the lithium salt can be promoted, thereby further effectively improving the low temperature resistance performance of the electrochemical device.

[0089] The manufacturing parameters and performance parameters of Examples 1-4 and 3-1 to 3-8 are as shown in Table 3.

[0090] [Table 3]

[0091] As can be seen from Examples 1-4 and 3-1 to 3-8 in Table 3, adding a fluorinated carbonate to the electrolyte and ensuring that the fluorinated carbonate content F satisfies the ranges 0.01%≦F≦5% and 0.005≦F / (A+B)≦0.5 effectively improves the low-temperature resistance and low-temperature discharge performance of lithium-ion batteries. This is because the fluorinated carbonate enhances the dissociation ability of lithium salts and increases the ionic conductivity of the electrolyte. However, a low content of fluorinated carbonate limits the dissociation ability, while a high content of fluorinated carbonate increases the viscosity of the electrolyte. When the contents of the compound of Formula I, lithium tetrafluoroborate, and fluorinated carbonate are within the above ranges, the conductivity of the electrolyte is improved while the composition of the passivation film is further optimized, resulting in a low-resistance passivation film, thereby simultaneously optimizing the low-temperature resistance and low-temperature discharge performance.

[0092] Table 4 shows the manufacturing parameters and performance parameters of Examples 1-4 and Examples 4-1 to 4-10.

[0093] [Table 4]

[0094] As can be seen from Examples 1-4 and 4-1 to 4-4 in Table 4, when the content S of the cyclic sulfur-oxygen double bond compound satisfies the ranges 0.01%≦S≦5.0% and 0.003≦S / (A+B)≦0.5, the cyclic sulfur-oxygen double bond compound can further enrich the positive and negative electrode interface components and increase the density of the passivation film, thereby effectively improving the low-temperature resistance performance and low-temperature discharge performance of the electrochemical device. If S is below this range, the improvement in the low-temperature resistance and low-temperature discharge performance of the electrochemical device is not significant. If S exceeds this range, the conductivity of the electrolyte decreases, and the improvement in the low-temperature resistance performance of the electrochemical device is insufficient.

[0095] As can be seen from Examples 4-5 to 4-6 and Examples 4-9 to 4-10 in Table 4, by adding a cyclic sulfur-oxygen double bond compound to the electrolyte, the cyclic sulfur-oxygen double bond compound can form a solvation structure in combination with the compound of Formula I and the compound of Formula II, which can promote the transport of lithium ions and thereby further improve the low-temperature discharge performance of the electrochemical device.

[0096] Both the compound of formula II and the fluorinated carbonate can enhance the dissociation ability of lithium salts. As can be seen from Examples 4-5 to 4-10, the compound of formula II and the fluorinated carbonate can further improve the low-temperature resistance performance of electrochemical devices by combining them with cyclic sulfur-oxygen double bond compounds.

[0097] It should be noted that, in this specification, relational terms such as "first," "second," and the like are used merely to distinguish one entity or operation from another, and do not necessarily require or imply the existence of an actual relationship or order between those entities or operations. Furthermore, the terms "comprise," "comprises," and similar terms are intended to imply a non-exclusive inclusion, meaning that a process, method, or article that includes a set of elements includes not only the explicitly listed elements, but also other elements not expressly listed or elements inherent in the process, method, or article.

[0098] The embodiments described in this specification are described in relation to each other, and the same or similar parts among the embodiments can be mutually referenced. In each embodiment, the differences from other embodiments are mainly described.

[0099] The above description is merely a preferred embodiment of the present application, and does not limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall all be included in the protection scope of the present application.

Claims

1. comprising lithium tetrafluoroborate and a compound of formula I, 【Chemistry 1】 wherein R in the compound of formula I is C unsubstituted or substituted with Ra. ２ ~C ６ alkyl group, unsubstituted or substituted with Ra ２ ~C ６ Alkenyl group, unsubstituted or substituted with Ra ２ ~C ６ Alkynyl group, unsubstituted or substituted with Ra ２ ~C ６ a nitrogen-containing heteroaromatic group or an unsubstituted or Ra-substituted C ６ ~C １２ The substituents Ra of each group are independently selected from fluorine or C １ ~C ６ fluorinated alkyl groups, 1. An electrolyte solution characterized in that, based on the total mass of the non-aqueous electrolyte solution, the mass percentage of the lithium tetrafluoroborate is A and the mass percentage of the compound of Formula I is B, wherein 0.1%≦A≦2%, and 0.01%≦B≦20%.

2. The electrolyte solution is (1) 0.2%≦A≦1.5%; (2) 2.0%≦B≦10%. The electrolyte solution according to claim 1, wherein B satisfies at least one of the following conditions:

3. 3. The electrolyte solution according to claim 1, wherein B / A satisfies 15≦B / A≦70.

4. The compound of formula I is 【Chemistry 2】 The electrolyte solution according to claim 1, comprising at least one of the following:

5. The non-aqueous electrolyte further comprises a compound of Formula II, The compound of formula II is 【Transformation 3】 The electrolyte solution according to claim 1, comprising at least one of the following:

6. 6. The electrolyte of claim 5, wherein the mass percentage of the compound of formula II is C, based on the total mass of the electrolyte, where 0.1%≦C≦20%.

7. the electrolyte solution contains a fluorinated carbonate containing at least one of fluoroethylene carbonate, bis(fluoromethyl)carbonate, and 3,3,3-trifluoropropylene carbonate; 2. The electrolyte of claim 1, wherein the mass percentage of the fluorinated carbonate, based on the total mass of the electrolyte, is F, where 0.01%≦F≦5% and 0.005≦F / (A+B)≦0.

5.

8. the electrolyte solution contains a cyclic sulfur-oxygen double bond compound including at least one of 1,3-propane sultone, ethylene sulfate, and methylene methanedisulfonate; 2. The electrolyte of claim 1, wherein the mass percentage of the cyclic sulfur-oxygen double bond compound is S, based on the total mass of the electrolyte, and wherein 0.01%≦S≦5.0% and 0.003≦S / (A+B)≦0.

5.

9. An electrochemical device comprising the electrolyte solution according to claim 1 or 2.

10. An electronic device comprising the electrochemical device of claim 9.

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