CN115966770B - Electrolyte, electrochemical device and electronic device comprising same - Google Patents
Electrolyte, electrochemical device and electronic device comprising same Download PDFInfo
- Publication number
- CN115966770B CN115966770B CN202310219108.9A CN202310219108A CN115966770B CN 115966770 B CN115966770 B CN 115966770B CN 202310219108 A CN202310219108 A CN 202310219108A CN 115966770 B CN115966770 B CN 115966770B
- Authority
- CN
- China
- Prior art keywords
- electrolyte
- temperature
- lithium
- compound
- electrochemical device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The application provides an electrolyte, an electrochemical device and an electronic device comprising the electrolyte, wherein the electrolyte comprises a compound of formula (I). The electrolyte comprising the compound of the formula (I) is applied to an electrochemical device, so that a stable positive solid interface film with good ion diffusion performance can be formed on the surface of a positive electrode of the electrochemical device, the problem that a positive active material is damaged under high voltage is solved, the oxygen release of a positive active material layer is reduced, the oxidative decomposition and gas production of the electrolyte under high temperature can be improved, and the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device are improved.
Description
Technical Field
The present disclosure relates to the field of electrochemical technology, and in particular, to an electrolyte, an electrochemical device and an electronic device including the electrolyte.
Background
Electrochemical devices (lithium ion batteries) are widely used in the fields of smart phones, wearable devices, consumer unmanned aerial vehicles, electric vehicles and the like due to the advantages of high energy density, long cycle life, no memory effect and the like. With the wide application of lithium ion batteries in the above fields, the energy density requirements of the lithium ion batteries in the market are increasing.
As the energy density increases, the voltage of the lithium ion battery also increases. The increase in voltage of the lithium ion battery can aggravate the damage to the positive electrode active material layer, so that the oxygen release of the positive electrode active material layer is aggravated, and the catalytic electrolyte is subjected to oxidative decomposition at high temperature to produce gas.
Disclosure of Invention
The purpose of the present application is to provide an electrolyte, an electrochemical device and an electronic device comprising the same, so as to improve the high-temperature gas production of the electrolyte. The specific technical scheme is as follows:
in a first aspect the present application provides an electrolyte comprising a compound of formula (I):
Preferably, R 1 、R 2 And R is 3 Each independently selected from the group consisting of hydrogen, halogen, formaldehyde, acetaldehyde, ethylene carbonyl, propylene carbonyl, methyl, ethyl, propyl, butyl, vinyl,Propenyl, butenyl, ethynyl, propynyl, butynyl, pyrrolyl or pyridyl; r is R 4 、R 5 And R is 6 Each independently selected from the group consisting of hydrogen, methylthio, dimethyl sulfide, methyl, ethyl, propyl, butyl, ethenyl, propenyl, butenyl, ethynyl, propynyl, butynyl, pyrrolyl, and pyridyl. The application of the electrolyte including the compound of formula (I) having a group in the above range to an electrochemical device can improve oxidative decomposition gas production of the electrolyte at high temperature, thereby improving high-temperature storage performance and high-temperature intermittent cycle performance of the electrochemical device.
More preferably, the compound of formula (I) comprises at least one of the following compounds:
the electrolyte comprising the compound of the formula (I) in the range is applied to an electrochemical device, can form a stable positive solid interface film with better ion diffusion performance on the surface of a positive electrode, can improve the problem that a positive active material is damaged under high voltage, reduces the oxygen release of a positive active material layer, and further improves the oxidative decomposition and gas production of the electrolyte at high temperature, thereby further improving the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device.
In some embodiments of the present application, 0.1.ltoreq.A.ltoreq.3. The mass percentage of the compound shown in the formula (I) is regulated within the range, so that a positive solid interface film with proper thickness is formed on the surface of the positive electrode, the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device are further improved, and meanwhile, the electrochemical device has good normal-temperature cycle performance.
In some embodiments of the present application, the electrolyte further comprises a carboxylic acid ester comprising at least one of ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, or butyl propionate; based on the mass of the electrolyte, the mass percentage of the carboxylic ester is B.ltoreq.B.ltoreq.70. The electrolyte comprises a compound of formula (I) and carboxylate in the range, and the content of the carboxylate is regulated and controlled in the range, so that the ion transmission capability of the electrolyte can be ensured, the anode solid interface film is more stable, the electrolyte is not easy to decompose in the charge-discharge cycle process, and the oxygen release of an anode active material layer is reduced, thereby improving the oxidative decomposition gas production of the electrolyte at high temperature, and further improving the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of an electrochemical device.
In some embodiments of the present application, 0.0005. Ltoreq.A/B.ltoreq.0.4. By regulating the value of A/B within the above range, the synergistic effect between the compound of formula (I) and the carboxylic ester can be fully exerted, and the electrode solid interface film is further stable and is not easy to decompose in the charge-discharge cycle process, so that the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device are further improved.
In some embodiments of the present application, 0.0075. Ltoreq.A/B.ltoreq.0.2. By regulating the value of a/B within the above range, the high-temperature storage performance, the high-temperature intermittent cycle performance, and the normal-temperature cycle performance of the electrochemical device can be made more excellent.
In some embodiments of the present application, the electrolyte further comprises an ester additive comprising at least one of ethylene carbonate, 1, 3-propane sultone, or fluoroethylene carbonate; based on the mass of the electrolyte, the mass percentage of the ester additive is D.5-18. The electrolyte comprises the ester additive in the range and the content of the ester additive is regulated in the range, so that the electrode solid interface film is more stable, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device are improved, and meanwhile, the electrochemical device has good high-temperature storage performance. In the present application, the electrode solid interface film refers to a positive electrode solid interface film and a negative electrode solid interface film.
In some embodiments of the present application, the electrolyte further comprises a nitrile compound, the nitrile compounds include malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelic dinitrile, suberonitrile, sebaconitrile, 3 '-oxydiproponitrile, hex-2-enedinitrile, fumaric dinitrile, 2-pentenenitrile, methylglutaronitrile, 4-cyanopimelic dinitrile, (Z) -but-2-enedinitrile, 2, 3-tetrafluorosuccinonitrile ethylene glycol bis (propionitrile) ether, 1,3, 5-valeronitrile, 1,3, 6-capro-tril, 1,2, 3-tris (2-cyanooxy) propane, 1, 3-propanetetracarbonitrile at least one of 2,2' - (1, 4-phenylene) dipropylene dinitrile, 1, 5-pentylternanitrile, 1, 4-butyltetranitrile, or 1, 6-hexyltetranitrile; based on the mass of the electrolyte, the mass percentage of the nitrile compound is E.ltoreq.E.ltoreq.8. The electrolyte comprises the nitrile compound in the range and the content of the nitrile compound is regulated and controlled in the range, so that the positive electrode solid interface film is more stable, is not easy to decompose in the charge-discharge cycle process, reduces the oxygen release of the positive electrode active material layer, and can improve the oxidative decomposition gas production of the electrolyte at high temperature, thereby being beneficial to improving the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device, and meanwhile, the electrochemical device has good normal-temperature cycle performance.
In some embodiments of the present application, the electrolyte comprises a lithium salt additive comprising at least one of lithium difluorophosphate, lithium tetrafluoroborate, lithium trifluoromethanesulfonyl imide, lithium bistrifluoromethanesulfonimide, lithium bisoxalato borate, or lithium difluorooxalato borate; based on the mass of the electrolyte, the mass percentage of the lithium salt additive is C.0.01-4. The electrolyte comprises the lithium salt additive in the range and the content of the lithium salt additive is regulated and controlled in the range, so that the electrode solid interface film is more stable and is not easy to decompose in the charge-discharge cycle process, thereby being beneficial to improving the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device, and meanwhile, the electrochemical device has good high-temperature storage performance.
In some embodiments of the present application, 0.1.ltoreq.A/C.ltoreq.30. By regulating the value of a/C within the above range, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device can be made more excellent.
The second aspect of the present application provides an electrochemical device comprising the electrolyte provided in the first aspect of the present application, and the electrochemical device provided in the present application has good high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance.
A third aspect of the present application provides an electronic device comprising the electrochemical device provided in the second aspect of the present application. The electrochemical device provided by the application has good high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance. Thus, the electronic device has longer service life.
The beneficial effects of this application:
the application provides an electrolyte, an electrochemical device and an electronic device comprising the electrolyte, wherein the electrolyte comprises a compound of formula (I). The electrolyte comprising the compound of the formula (I) is applied to an electrochemical device, so that a stable positive solid interface film with good ion diffusion performance can be formed on the surface of a positive electrode of the electrochemical device, the problem that a positive active material is damaged under high voltage is solved, the oxygen release of a positive active material layer is reduced, the oxidative decomposition and gas production of the electrolyte under high temperature can be improved, and the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device are improved.
Of course, not all of the above advantages need be achieved simultaneously in the practice of any one of the products or methods of this application.
Detailed Description
The following description of the technical solutions in the embodiments of the present application will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present application, but not all embodiments. Based on the embodiments herein, a person of ordinary skill in the art would be able to obtain all other embodiments based on the disclosure herein, which are within the scope of the disclosure herein.
In the specific embodiment of the present application, the present application is explained using a lithium ion battery as an example of an electrochemical device, but the electrochemical device of the present application is not limited to a lithium ion battery.
In a first aspect the present application provides an electrolyte comprising a compound of formula (I):
The electrolyte comprising the compound of the formula (I) is applied to an electrochemical device, so that a stable positive solid interface film with proper thickness and good ion diffusion performance can be formed on the surface of a positive electrode, the problem that a positive active material is damaged at high voltage can be solved, and the oxygen release of a positive active material layer is reduced, thereby improving the oxidative decomposition and gas production of the electrolyte at high temperature, and further improving the high-temperature storage performance and high-temperature intermittent cycle performance of the electrochemical device. When A is too small, the thickness of the positive electrode solid interface film formed on the surface of the positive electrode is too small, even a complete positive electrode solid interface film cannot be formed on the surface of the positive electrode, so that the oxidative decomposition of the electrolyte at high temperature cannot be improved to produce gas, the high-temperature storage performance of the electrochemical device cannot be improved, and when A is too large, the thickness of the positive electrode solid interface film formed on the surface of the positive electrode is too large, the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device cannot be improved. The mass percentage of the compound shown in the formula (I) is regulated and controlled within the range, so that a positive solid interface film with proper thickness is formed on the surface of the positive electrode, and the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device can be improved. In the present application, "high temperature" means a temperature of 45℃or higher, and normal temperature means a temperature of 25.+ -. 5 ℃.
Preferably, R 1 、R 2 And R is 3 Each independently selected from the group consisting of atom, halogen, formaldehyde, acetaldehyde, ethylene carbonyl, propylene carbonyl, methyl, ethyl, propyl, butyl, ethenyl, propenyl, butenyl, ethynyl, propynyl, butynyl, pyrrole, or pyridyl; r is R 4 、R 5 And R is 6 Each independently selected from the group consisting of hydrogen, methylthio, dimethyl sulfide, methyl, ethyl, propyl, butyl, ethenyl, propenyl, butenyl, ethynyl, propynyl, butynyl, pyrrolyl, and pyridyl. The electrolyte comprising the compound of the formula (I) with the groups in the range is applied to an electrochemical device, a stable positive solid interface film with better ion diffusion performance can be formed on the surface of a positive electrode, the problem that a positive active material is destroyed under high voltage can be solved, the oxygen release of a positive active material layer is reduced, the oxidative decomposition gas production of the electrolyte under high temperature is further improved, and therefore the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device are further improved.
More preferably, the compound of formula (I) comprises at least one of the following compounds:
the electrolyte comprising the compound of the formula (I) in the range is applied to an electrochemical device, can form a stable positive solid interface film with better ion diffusion performance on the surface of a positive electrode, can improve the problem that a positive active material is damaged under high voltage, reduces the oxygen release of a positive active material layer, and further improves the oxidative decomposition and gas production of the electrolyte at high temperature, thereby further improving the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device.
In some embodiments of the present application, the electrolyte further comprises a carboxylic acid ester comprising at least one of ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, or butyl propionate; based on the mass of the electrolyte, the mass percentage of the carboxylic ester is B.ltoreq.B.ltoreq.70. For example, B may be 10, 20, 30, 40, 50, 60, 70 or a range of any two values therein. The electrolyte comprises a compound of formula (I) and carboxylate in the range, and the content of the carboxylate is regulated and controlled in the range, so that the ion transmission capability of the electrolyte can be ensured, the anode solid interface film is more stable, the electrolyte is not easy to decompose in the charge-discharge cycle process, the oxygen release of an anode active material layer is reduced, and the oxidative decomposition and gas production of the electrolyte at high temperature can be improved, thereby being beneficial to improving the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of an electrochemical device.
In some embodiments of the present application, 0.0005. Ltoreq.A/B.ltoreq.0.4, preferably 0.0075. Ltoreq.A/B.ltoreq.0.2. For example, a/B may be 0.0005, 0.0008, 0.001, 0.005, 0.01, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, or a range of any two values therein. By regulating the value of A/B within the above range, the synergistic effect between the compound of formula (I) and the carboxylate can be fully exerted, the ion transmission capability of the electrolyte can be ensured, the anode solid interface film can be further stabilized, the anode solid interface film is not easy to decompose in the charge-discharge cycle process, the oxygen release of the anode active material layer is reduced, and the oxidative decomposition gas production of the electrolyte at high temperature can be improved, so that the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device are further improved.
In some embodiments of the present application, the electrolyte further comprises an ester additive comprising at least one of Vinylene Carbonate (VC), ethylene carbonate (VEC), 1, 3-propane sultone, or fluoroethylene carbonate (FEC); based on the mass of the electrolyte, the mass percentage of the ester additive is D.5-18. For example, D may be 0.5, 1, 1.5, 3, 4.5, 6, 7.5, 9, 10, 11, 12, 15, 16, 18 or a range of any two values therein. The electrolyte comprises the ester additive in the range and the content of the ester additive is regulated and controlled in the range, so that the electrode solid interface film is more stable and is not easy to decompose in the charge-discharge cycle process, thereby being beneficial to improving the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device, and meanwhile, the electrochemical device has good high-temperature storage performance.
In some embodiments of the present application, the electrolyte further comprises a nitrile compound, the nitrile compounds include malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelic dinitrile, suberonitrile, sebaconitrile, 3 '-oxydiproponitrile, hex-2-enedinitrile, fumaric dinitrile, 2-pentenenitrile, methylglutaronitrile, 4-cyanopimelic dinitrile, (Z) -but-2-enedinitrile, 2, 3-tetrafluorosuccinonitrile ethylene glycol bis (propionitrile) ether, 1,3, 5-valeronitrile, 1,3, 6-capro-tril, 1,2, 3-tris (2-cyanooxy) propane, 1, 3-propanetetracarbonitrile at least one of 2,2' - (1, 4-phenylene) dipropylene dinitrile, 1, 5-pentylternanitrile, 1, 4-butyltetranitrile, or 1, 6-hexyltetranitrile; based on the mass of the electrolyte, the mass percentage of the nitrile compound is E.ltoreq.E.ltoreq.8, for example, E can be 1,2,3, 4, 5, 6, 7, 8 or a range consisting of any two values. The electrolyte comprises the nitrile compound in the range and the content of the nitrile compound is regulated and controlled in the range, so that the positive electrode solid interface film is more stable, is not easy to decompose in the charge-discharge cycle process, reduces the oxygen release of the positive electrode active material layer, and can improve the oxidative decomposition gas production of the electrolyte at high temperature, thereby being beneficial to improving the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device, and meanwhile, the electrochemical device has good normal-temperature cycle performance.
In some embodiments of the present application, the electrolyte comprises a lithium salt additive comprising at least one of lithium difluorophosphate, lithium tetrafluoroborate, lithium trifluoromethanesulfonyl imide, lithium bistrifluoromethanesulfonimide, lithium bisoxalato borate, or lithium difluorooxalato borate; the lithium salt additive is present in an amount of 0.01.ltoreq.C.ltoreq.4 by mass based on the mass of the electrolyte, e.g.C may be 0.01, 0.05, 0.1, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4 or a range of any two values therein. The electrolyte comprises the lithium salt additive in the range and the content of the lithium salt additive is regulated and controlled in the range, so that the electrode solid interface film is more stable and is not easy to decompose in the charge-discharge cycle process, thereby improving the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device, and simultaneously the electrochemical device has good high-temperature storage performance.
In some embodiments of the present application, 0.1.ltoreq.A/C.ltoreq.30. For example, a/C may be 0.1, 0.2, 0.5, 1, 2, 3.5, 5, 7, 10, 15, 18, 21, 27, 30 or a range of any two values therein. By regulating the value of a/C within the above range, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device can be made more excellent.
In some embodiments of the present application, the electrolyte comprises a compound of formula (I), a carbonate solvent, and a lithium salt, wherein the carbonate solvent comprises at least one of Ethylene Carbonate (EC), propylene Carbonate (PC), butylene Carbonate (BC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), dioctyl carbonate, dipentyl carbonate, ethylisobutyl carbonate, isopropylmethyl carbonate, di-n-butyl carbonate, diisopropylcarbonate, or propylcarbonate; the lithium salt includes lithium hexafluorophosphate. The mass percentage of the carbonate solvent is 80 to 88 percent and the mass percentage of the lithium salt is 8 to 15 percent based on the mass of the electrolyte. For example, the carbonate solvent may be 80%, 82%, 84%, 86%, 88% by mass or a range of any two of these values, and the lithium salt may be 8%, 9%, 10%, 11%, 13%, 15% by mass or a range of any two of these values. The electrolyte comprises the carbonate solvent and the lithium salt in the above ranges, and the content of the carbonate solvent and the lithium salt is regulated and controlled in the above ranges, so that an electrolyte environment which enables the electrode solid interface film to be more stable can be obtained, and the high-temperature storage performance and the high-temperature intermittent cycle performance of the electrochemical device can be improved.
In some embodiments of the present application, the electrolyte includes a compound of formula (I), a carbonate solvent, a lithium salt, and a carboxylic acid ester, and the electrolyte may further include at least one of an ester additive, a nitrile compound, or a lithium salt additive. Wherein the carbonate solvent comprises at least one of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, dioctyl carbonate, dipentyl carbonate, ethylisobutyl carbonate, isopropylmethyl carbonate, di-n-butyl carbonate, diisopropyl carbonate or propyl carbonate; the lithium salt includes lithium hexafluorophosphate. The mass percentage of the carbonate solvent is 10 to 80% and the mass percentage of the lithium salt is 8 to 15% based on the mass of the electrolyte. For example, the carbonate-based solvent may be 10%, 15%, 20%, 30%, 40%, 50%, 60%, 70%, 80% by mass or a range of any two values therein, and the lithium salt may be 8%, 9%, 10%, 11%, 13%, 15% by mass or a range of any two values therein. The mass percent of the carboxylic ester is 10 to 70 percent, the mass percent of the ester additive is 0.5 to 18 percent, the mass percent of the nitrile compound is 1 to 8 percent, and the mass percent of the lithium salt additive is 0.01 to 4 percent. The electrolyte comprises a carbonic ester solvent, lithium salt and carboxylic ester in the above ranges, and optionally the electrolyte further comprises at least one of an ester additive, a nitrile compound or a lithium salt additive, and the content of the components is regulated and controlled in the above ranges, so that the electrode solid interface film is more stable, and the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the electrochemical device are improved.
The second aspect of the present application provides an electrochemical device comprising the electrolyte provided in the first aspect of the present application, and the electrochemical device provided in the present application has good high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance.
The electrochemical device of the application also comprises an electrode assembly, wherein the electrode assembly comprises a positive electrode plate, a negative electrode plate and a separation membrane.
The positive electrode sheet is not particularly limited as long as the object of the present application can be achieved. For example, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The present application is not particularly limited as long as the object of the present application can be achieved. For example, the positive electrode current collector may include an aluminum foil or an aluminum alloy foil, or the like. The positive electrode active material layer of the present application contains a positive electrode active material. The kind of the positive electrode active material is not particularly limited as long as the object of the present application can be achieved. For example, the positive electrode active material may include lithium nickel cobalt manganese oxide (811, 622, 523, 111), lithium nickel cobalt aluminate, lithium iron phosphate, lithium-rich manganese-based material, lithium cobalt oxide (LiCoO) 2 ) At least one of lithium manganate, lithium iron manganese phosphate, lithium titanate, and the like. In the present application, the positive electrode active material may further contain a non-metal element, for example, at least one of fluorine, phosphorus, boron, chlorine, silicon, sulfur, and the like, which further improves the stability of the positive electrode active material. In the present application, the thicknesses of the positive electrode current collector and the positive electrode active material layer are not particularly limited as long as the objects of the present application can be achieved. For example, the thickness of the positive electrode current collector is 5 μm to 20 μm, preferably 6 μm to 18 μm. The thickness of the single-sided positive electrode active material layer is 30 μm to 120 μm. In the present application, the positive electrode active material layer may be provided on one surface in the thickness direction of the positive electrode current collector, or may be provided on both surfaces in the thickness direction of the positive electrode current collector. The term "surface" as used herein may be The entire region of the positive electrode current collector may be a partial region of the positive electrode current collector, and the present application is not particularly limited as long as the object of the present application can be achieved. The positive electrode active material layer of the present application may further contain a conductive agent and a binder.
The negative electrode sheet is not particularly limited as long as the object of the present application can be achieved. For example, the negative electrode tab includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector. The negative electrode current collector is not particularly limited as long as the object of the present application can be achieved. For example, the negative electrode current collector may include copper foil, copper alloy foil, nickel foil, titanium foil, foam nickel, foam copper, or the like. The anode active material layer of the present application contains an anode active material. The kind of the negative electrode active material is not particularly limited in the present application, as long as the object of the present application can be achieved. For example, the anode active material may contain natural graphite, artificial graphite, intermediate phase micro carbon spheres (MCMB), hard carbon, soft carbon, silicon-carbon composite, siO x （0<x is less than or equal to 2) or metallic lithium, etc. In the present application, the thicknesses of the anode current collector and the anode active material layer are not particularly limited as long as the object of the present application can be achieved. For example, the negative electrode current collector has a thickness of 4 μm to 12 μm, and the single-sided negative electrode active material layer has a thickness of 30 μm to 130 μm. In the present application, the anode active material layer may be provided on one surface in the anode current collector thickness direction, or may be provided on both surfaces in the anode current collector thickness direction. The "surface" here may be the entire region of the negative electrode current collector or may be a partial region of the negative electrode current collector, and the present application is not particularly limited as long as the object of the present application can be achieved. The anode active material layer of the present application may further contain a conductive agent and a binder.
The above-mentioned conductive agent and binder are not particularly limited as long as the object of the present application can be achieved. For example, the conductive agent may include at least one of conductive carbon black (Super P), carbon Nanotubes (CNTs), carbon nanofibers, crystalline graphite, carbon dots, graphene, or the like. The binder may include at least one of polyacrylate, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyimide, polyamideimide, styrene Butadiene Rubber (SBR), polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), aqueous acrylic resin, carboxymethyl cellulose (CMC), sodium carboxymethyl cellulose (CMC-Na), or the like.
The separator is not particularly limited as long as the object of the present application can be achieved. For example, the release film may include a substrate layer and a surface treatment layer. The substrate layer may be a nonwoven fabric, a film, or a composite film having a porous structure, and the material of the substrate layer may include at least one of polyethylene, polypropylene, polyethylene terephthalate, polyimide, or the like. Optionally, a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite membrane may be used. Optionally, a surface treatment layer is disposed on at least one surface of the substrate layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or may be a layer formed by mixing a polymer and an inorganic material. For example, the inorganic layer includes inorganic particles and a binder, and the inorganic particles are not particularly limited, and may be selected from at least one of alumina, silica, magnesia, titania, hafnia, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconia, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium sulfate, and the like, for example. The binder is not particularly limited, and may be at least one selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polytetrafluoroethylene, polyhexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyvinylpyrrolidone, polyvinyl ether, and polymethyl methacrylate, for example. The polymer layer contains polymer, and the material of the polymer comprises at least one of polyamide, polyacrylonitrile, acrylic polymer, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or polyvinylidene fluoride-hexafluoropropylene and the like. In the present application, the thickness of the separator is not particularly limited as long as the object of the present application can be achieved, for example, the thickness of the separator may be 5 μm to 500 μm.
The electrochemical device of the present application is not particularly limited, and may include any device in which an electrochemical reaction occurs. In one embodiment of the present application, the electrochemical device may include, but is not limited to: lithium ion secondary batteries (lithium ion batteries), lithium metal secondary batteries, sodium ion secondary batteries (sodium ion batteries), sodium metal secondary batteries, lithium polymer secondary batteries, lithium ion polymer secondary batteries, and the like.
The process of preparing the electrochemical device is well known to those skilled in the art, and the present application is not particularly limited, and may include, for example, but not limited to, the following steps: sequentially stacking the positive electrode plate, the isolating film and the negative electrode plate, winding and folding the positive electrode plate, the isolating film and the negative electrode plate according to the requirements to obtain an electrode assembly with a winding structure, placing the electrode assembly into a packaging bag, injecting electrolyte into the packaging bag, and sealing to obtain an electrochemical device; or sequentially stacking the positive electrode plate, the isolating film and the negative electrode plate, fixing four corners of the whole lamination structure by using adhesive tapes to obtain an electrode assembly of the lamination structure, placing the electrode assembly into a packaging bag, injecting electrolyte into the packaging bag, and sealing to obtain the electrochemical device. In addition, an overcurrent prevention element, a guide plate, or the like may be placed in the package as needed, thereby preventing the pressure inside the electrochemical device from rising and overcharging and discharging. The packaging bag is not limited in this application, and a person skilled in the art can select according to actual needs, so long as the purpose of this application can be achieved. For example, an aluminum plastic film package may be used.
A third aspect of the present application provides an electronic device comprising the electrochemical device provided in the second aspect of the present application. The electrochemical device provided by the application has good high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance. Thus, the electronic device has longer service life.
The electronic device of the present application is not particularly limited, 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-input computer, a mobile computer, an electronic book player, a portable telephone, a portable facsimile machine, a portable copier, a portable printer, a headset, a video recorder, a liquid crystal television, a portable cleaner, a portable CD-player, a mini-compact disc, a transceiver, an electronic organizer, a calculator, a memory card, a portable audio recorder, a radio, a backup power source, a motor, an automobile, a motorcycle, a power assisted bicycle, a lighting fixture, a toy, a game machine, a clock, an electric tool, a flash light, a camera, a household large battery or a lithium ion capacitor, and the like.
Examples
Hereinafter, embodiments of the present application will be described in more detail with reference to examples and comparative examples. The various tests and evaluations were carried out according to the following methods. Unless otherwise specified, "parts" and "%" are mass references.
Test method and test equipment
High temperature storage performance test:
the high temperature storage performance of the lithium ion battery was evaluated by storing the thickness expansion rate of the lithium ion battery at 60 ℃ for a storage time of 10%. The specific test flow is as follows: testing the initial thickness D1 of the lithium ion battery at 25 ℃; and (3) charging the lithium ion battery to 4.5V at a constant current of 0.5C and then charging the lithium ion battery to a constant voltage of 4.5V until the current is 0.05C at 25 ℃, then standing the lithium ion battery in a high-temperature furnace at 60 ℃, testing the thickness of the lithium ion battery every day, recording the thickness D2 of the lithium ion battery, and recording the number of days when the thickness expansion rate is 10% according to the calculation method of the thickness expansion rate, wherein the thickness expansion rate is= (D2-D1)/D1×100%, and is used as an index for evaluating the high-temperature storage performance of the lithium ion battery.
Testing of high temperature intermittent cycle performance:
the specific test flow is as follows: the lithium ion battery is placed in a high-temperature furnace at 45 ℃, the lithium ion battery is charged to 4.5V at a constant current of 0.5C, then is charged to 0.05C at a constant voltage, the initial full charge thickness of the lithium ion battery is measured, the lithium ion battery is placed at 45 ℃ for 1170min, and then is discharged to 3.0V at a constant current of 0.5C, and the cycle is the first time. And (3) circulating the lithium ion battery for a plurality of times according to the conditions, and measuring the full charge thickness of the lithium ion battery each time. And repeating the charge-discharge cycle with the capacity of the first discharge being 100%, stopping the test until the discharge capacity retention rate is reduced to 70% of the first discharge capacity, and recording the cycle number as an index for evaluating the intermittent cycle capacity retention rate of the lithium ion battery.
Capacity retention= (capacity after each turn of discharge/first turn discharge capacity) ×100%.
Testing of normal temperature cycle performance:
under the condition of 25 ℃, the lithium ion battery is charged to 4.25V at a constant current of 1.2C, is charged to 0.7C at a constant voltage of 4.25V, is charged to 4.5V at a constant current of 0.7C, is charged to 0.05C at a constant voltage of 4.5V, is kept stand for 5min, is discharged to 3.0V at a constant current of 0.5C, and is circulated for the first time at this time, and the discharge capacity is recorded. And (3) cycling the lithium ion battery for a plurality of times according to the conditions, and measuring the discharge capacity of the lithium ion battery every time. And repeating the charge-discharge cycle with the capacity of the first discharge being 100%, stopping the test when the discharge capacity retention rate is reduced to 80% of the first discharge capacity, and recording the cycle number as an index for evaluating the normal-temperature cycle capacity retention rate of the lithium ion battery. Capacity retention= (capacity after each turn of discharge/first turn discharge capacity) ×100%.
Example 1-1
< preparation of electrolyte >
In an argon atmosphere glove box with the water content less than 10ppm, mixing EC, PC and DEC according to the mass ratio of 10:30:60 to obtain a base solvent, and then adding lithium salt LiPF into the base solvent 6 And the compound shown in the formula (I) is shown in the formula (I-1), and the electrolyte is obtained after uniform stirring. Wherein based on the mass of the electrolyte, liPF 6 The mass percentage of the compound of the formula (I) is 12 percent and the mass percentage of the compound of the formula (I) is 0.3 percent.
< preparation of Positive electrode sheet >
LiCoO as positive electrode active material 2 Mixing conductive carbon black serving as a conductive agent, PVDF serving as a binder according to the mass ratio of 95:2:3, adding N-methylpyrrolidone (NMP), and uniformly stirring under the action of a vacuum stirrer to obtain the anode with the solid content of 70wt%And (3) sizing. The positive electrode slurry was uniformly coated on one surface of a positive electrode current collector aluminum foil having a thickness of 12 μm, and the aluminum foil was baked at 85 ℃ for 4 hours to obtain a positive electrode sheet coated with a single-sided positive electrode active material layer having a coating thickness of 110 μm and a width of 74 mm. Repeating the steps on the other surface of the aluminum foil to obtain the positive electrode plate with the double-sided coating positive electrode active material layer. And then drying for 4 hours at the temperature of 85 ℃ under vacuum, and carrying out cold pressing, cutting and slitting to obtain the positive pole piece with the specification of 74mm multiplied by 867 mm.
< preparation of negative electrode sheet >
Mixing the negative electrode active material graphite, the binder styrene-butadiene rubber and the negative electrode thickener sodium carboxymethyl cellulose according to the mass ratio of 95:2:3, adding deionized water, and uniformly stirring under the action of a vacuum stirrer to obtain the negative electrode slurry with the solid content of 75 wt%. The negative electrode slurry was uniformly coated on one surface of a negative electrode current collector copper foil having a thickness of 12 μm, and the copper foil was baked at 85 ℃ for 4 hours to obtain a negative electrode tab coated with a negative electrode active material layer on one side having a coating thickness of 130 μm and a width of 76.6 mm. Repeating the steps on the other surface of the copper foil to obtain the negative electrode plate with the double-sided coating negative electrode active material layer. And then drying for 4 hours at the temperature of 85 ℃ under vacuum, and obtaining the negative electrode plate with the specification of 76.6mm multiplied by 875mm through cold pressing, cutting and slitting.
< preparation of isolation Membrane >
Mixing PVDF and alumina ceramic according to a mass ratio of 1:2, adding NMP as a solvent, preparing ceramic layer slurry with a solid content of 12wt%, uniformly stirring, uniformly coating the slurry on one surface of a polyethylene substrate with a thickness of 5 mu m, and drying to obtain the isolation film with a single-sided coating of 2 mu m alumina ceramic layer. PVDF is added into NMP solvent and stirred uniformly, PVDF slurry with 25wt% of solid content is prepared, and then 0.15mg/cm of PVDF slurry is coated on the surface of the alumina ceramic layer 2 Drying at 85deg.C for 4 hours, and finally, the other surface of the polyethylene substrate is also coated with 0.15mg/cm 2 Is baked at 85 ℃ for 4 hours to obtain the isolating film.
< preparation of lithium ion Battery >
And sequentially stacking the prepared positive electrode plate, the isolating film and the negative electrode plate, enabling one surface of the isolating film coated with the aluminum oxide ceramic layer and PVDF to face the positive electrode plate, and only one surface coated with PVDF to face the negative electrode plate, so that the isolating film is positioned between the positive electrode plate and the negative electrode plate to play a role of isolation, and then winding to obtain the electrode assembly. And (3) after welding the electrode lugs, placing the electrode assembly into an aluminum plastic film packaging bag, drying the electrode assembly in a vacuum oven at 85 ℃ for 12 hours to remove water, injecting the prepared electrolyte, and carrying out the procedures of vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery.
Examples 1-2 to 1-15
The procedure of example 1-1 was repeated, except that the type and mass percentage of the compound of formula (I) and the mass percentage of the base solvent were changed as shown in Table 1 in < preparation of electrolyte >, and the mass percentage of the lithium salt was not changed.
Examples 2-1 to 2-21
The procedure of examples 1 to 12 was repeated, except that in the < preparation of electrolyte > carboxylic acid ester was added as shown in Table 2, and the type and mass% of the compound of formula (I), the type and mass% of the carboxylic acid ester were adjusted as shown in Table 2, and the mass% of the base solvent was changed, with the exception that the mass% of the lithium salt was unchanged.
Examples 3-1 to 3-10
The procedure of examples 2 to 16 was repeated, except that in the < preparation of electrolyte > as shown in Table 3, an ester additive and/or a nitrile compound were/is added, and the type and mass percentage of the ester additive, the type and mass percentage of the nitrile compound were/is adjusted as shown in Table 3, and the mass percentage of the base solvent was changed, whereby the mass percentage of the lithium salt was not changed.
Examples 4-1 to 4-14
The procedure of examples 3 to 7 was repeated, except that in < preparation of electrolyte > as shown in Table 4, a lithium salt additive was added, and the type and mass% of the compound of formula (I), the type and mass% of the lithium salt additive, and the mass% of the base solvent were changed as shown in Table 4.
Comparative examples 1 to 1
The procedure of example 1-1 was repeated, except that the compound of the formula (I) was not added to the process of < preparation of electrolyte > and the mass percentage of the base solvent was changed and the mass percentage of the lithium salt was not changed.
Comparative examples 1 to 2
The procedure of example 1-1 is followed, except that the compound of formula (I) is replaced with diethyl (thiophen-2-ylmethyl) phosphate as an additive in < preparation of electrolyte >.
Comparative examples 1-3 to 1-4
The procedure of example 1-1 was repeated, except that the mass percentage of the compound of formula (I) and the mass percentage of the base solvent were changed as shown in Table 1 in < preparation of electrolyte >, and the mass percentage of the lithium salt was not changed.
Comparative example 2-1
The procedure of examples 2 to 9 was repeated, except that the compound of the formula (I) was not added as shown in Table 2 in the < preparation of electrolyte solution >, the mass percentage of the base solvent was changed and the mass percentage of the lithium salt was not changed.
Comparative example 3-1
The procedure of examples 3 to 4 was followed except that the compound of formula (I) was not added to the process of < preparation of electrolyte > and the mass percentage of the base solvent was changed and the mass percentage of the lithium salt was unchanged.
Comparative example 3-2
The procedure of examples 3 to 5 is followed, except that the compound of formula (I) is not added in < preparation of electrolyte > and the mass percentage of the base solvent is changed and the mass percentage of the lithium salt is unchanged.
Comparative examples 3 to 3
The procedure of examples 3 to 7 was followed, except that the compound of the formula (I) was not added to the process of < preparation of electrolyte > and the mass percentage of the base solvent was changed and the mass percentage of the lithium salt was not changed.
Comparative example 4-1
The procedure of examples 4 to 5 was followed except that the compound of formula (I) was not added to the process of < preparation of electrolyte > and the mass percentage of the base solvent was changed and the mass percentage of the lithium salt was unchanged.
The preparation parameters and performance parameters of each example and comparative example are shown in tables 1 to 4.
TABLE 1
Note that: the "/" in Table 1 indicates no relevant preparation parameters.
As can be seen from examples 1-1 to 1-9, comparative examples 1-1 and comparative examples 1-2, the application of the electrolyte including the compound of formula (I) to a lithium ion battery can extend the storage time of the lithium ion battery at 60 ℃ and increase the number of high-temperature intermittent cycles of the lithium ion battery, thereby enabling the lithium ion battery to have better high-temperature storage performance and high-temperature intermittent cycle performance.
The mass percent A% of the compounds of formula (I) generally affects the high temperature storage performance and the high temperature intermittent cycling performance of lithium ion batteries. It can be seen from examples 1 to 5, examples 1 to 10 to examples 1 to 15, comparative examples 1 to 3 and comparative examples 1 to 4 that when the a value is too small, the storage time of the lithium ion battery at 60 ℃ is short. When the A value is too large, the storage time of the lithium ion battery at 60 ℃ is short and the number of high-temperature intermittent cycle turns is small. When A is more than or equal to 0.01 and less than or equal to 5, the lithium ion battery has better high-temperature storage performance and more high-temperature intermittent cycle numbers. When A is more than or equal to 0.1 and less than or equal to 3, the storage time of the lithium ion battery at 60 ℃ is longer, and the number of high-temperature intermittent circulation turns is more. Therefore, the regulation and control A is in the range of the application, the storage time of the lithium ion battery at 60 ℃ is longer, the number of high-temperature intermittent cycle turns is more, and the lithium ion battery has better high-temperature storage performance and high-temperature intermittent cycle performance.
TABLE 2
Note that: the "/" in Table 2 indicates no relevant parameters.
The kind of carboxylic acid ester generally affects the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the lithium ion battery. As can be seen from examples 1-12 and examples 2-1 to 2-6, the lithium ion battery with the carboxylic acid ester in the range of the application has longer storage time at 60 ℃ and more cycle numbers at normal temperature and can maintain more high-temperature intermittent cycle numbers, so that the electrolyte solution further introduces the carboxylic acid ester under the condition of containing the compound shown as the formula (I), so that the lithium ion battery has better high-temperature storage performance and normal-temperature cycle performance while having good high-temperature intermittent cycle performance.
The mass percent of the carboxylic ester B% generally affects the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the lithium ion battery, and when the B value is within the range of the application, the storage time of the lithium ion battery at 60 ℃ is longer, the number of high-temperature intermittent cycle turns and the number of normal-temperature cycle turns are more, namely the lithium ion battery has better high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance as can be seen from examples 2-2, 2-7 and 2-12.
The ratio of the mass percent of the compound of formula (I) to the mass percent of the carboxylate A/B generally affects the high temperature storage performance, the high temperature intermittent cycle performance and the normal temperature cycle performance of the lithium ion battery, and it can be seen from examples 2-2, 2-13 to 2-21 that the lithium ion battery has longer storage time at 60 ℃ and more high temperature intermittent cycle numbers and normal temperature cycle numbers when A/B is within the scope of the present application. Namely, the lithium ion battery has better high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance.
As can be seen from examples 2 to 9, examples 1 to 12 and comparative examples 2 to 1, when the electrolyte of the lithium ion battery includes only the compound of formula (I) or only the carboxylate, the storage time of the lithium ion battery at 60 ℃ is short, the number of high-temperature intermittent cycles and the number of normal-temperature cycles are small; when the electrolyte of the lithium ion battery simultaneously comprises the compound shown in the formula (I) and carboxylic ester, the lithium ion battery has longer storage time at 60 ℃, more high-temperature intermittent cycle numbers and more normal-temperature cycle numbers, namely the lithium ion battery has better high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance.
TABLE 3 Table 3
Note that: the "/" in Table 3 indicates no relevant preparation parameters.
The type of the ester additive and its mass percentage content D% generally affect the high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance of the lithium ion battery. As can be seen from examples 2-16 and examples 3-1 to 3-4, the lithium ion battery with the class and D value of the ester additive in the range of the application has longer storage time at 60 ℃, more high-temperature intermittent cycle number and more normal-temperature cycle number, so that the electrolyte can improve the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the lithium ion battery at the same time by further introducing the ester additive under the condition that the electrolyte contains the compound shown as the formula (I).
The type of nitrile compound and its mass percentage content E% generally affect the high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance of the lithium ion battery. As can be seen from examples 2 to 16, examples 3 to 5 and examples 3 to 6, the type and E value of the nitrile compound are in the range of the present application, and the storage time at 60 ℃ is longer, the number of high-temperature intermittent cycles is more, and the number of normal-temperature intermittent cycles is more, so that it is illustrated that the electrolyte solution further introduces the nitrile compound under the condition of containing the compound of formula (I), and the high-temperature storage performance and the high-temperature intermittent cycle performance of the lithium ion battery can be further improved.
It can be seen from examples 2 to 16, examples 3 to 7 to examples 3 to 8 that when the electrolyte of the lithium ion battery includes both the ester additive and the nitrile compound, the lithium ion battery has a longer storage time at 60 c, and has more intermittent cycles at high temperature and more cycles at normal temperature. Therefore, the electrolyte can further improve the high-temperature storage performance, the high-temperature intermittent cycle performance and the normal-temperature cycle performance of the lithium ion battery by simultaneously introducing the ester additive and the nitrile compound under the condition of containing the compound shown as the formula (I).
As can be seen from examples 3 to 4, examples 2 to 16 and comparative example 3 to 1, when the electrolyte of the lithium ion battery includes only the compound of formula (I) or only the ester additive, the storage time of the lithium ion battery at 60 ℃ is short, and the number of high-temperature intermittent cycles and the number of normal-temperature cycles are small; when the electrolyte of the lithium ion battery simultaneously comprises the compound shown in the formula (I) and the ester additive, the lithium ion battery has longer storage time at 60 ℃, more high-temperature intermittent cycle numbers and more normal-temperature cycle numbers, namely the lithium ion battery has better high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance.
As can be seen from examples 3 to 5, examples 2 to 16 and comparative examples 3 to 2, when the electrolyte of the lithium ion battery includes only the compound of formula (I) or only the nitrile compound, the storage time of the lithium ion battery at 60 ℃ is short, the number of intermittent cycles at high temperature and the number of cycles at normal temperature are small; when the electrolyte of the lithium ion battery comprises the compound shown in the formula (I) and the nitrile compound, the lithium ion battery has longer storage time at 60 ℃, more high-temperature intermittent cycle numbers and more normal-temperature cycle numbers, namely the lithium ion battery has better high-temperature storage performance and high-temperature intermittent cycle performance and good normal-temperature cycle performance.
As can be seen from examples 3 to 7, examples 2 to 16 and comparative examples 3 to 3, when the electrolyte of the lithium ion battery includes only the compound of formula (I) or only the nitrile compound and the nitrile compound, the storage time of the lithium ion battery at 60 ℃ is short, the number of intermittent cycles at high temperature and the number of cycles at normal temperature are small; when the electrolyte of the lithium ion battery simultaneously comprises the compound of the formula (I), the ester additive and the nitrile compound, the lithium ion battery has longer storage time at 60 ℃, more high-temperature intermittent cycle numbers and more normal-temperature cycle numbers, namely the lithium ion battery has better high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance.
TABLE 4 Table 4
Note that: the "/" in Table 4 indicates no relevant preparation parameters.
The type of lithium salt additive and its mass percentage content C% generally affect the high-temperature storage performance, high-temperature intermittent cycle performance and normal-temperature cycle performance of lithium ion batteries. As can be seen from examples 3-7, 4-1 to 4-9, the lithium ion battery with the lithium salt additive having the types and C values within the range of the present application has a longer storage time at 60 ℃ and a larger number of high-temperature intermittent cycles and normal-temperature cycles, thereby indicating that the electrolyte solution further introduces the lithium salt additive under the condition of containing the compound of formula (I), thereby improving the high-temperature intermittent cycle performance and normal-temperature cycle performance of the lithium ion battery, and simultaneously the lithium ion battery has better high-temperature storage performance.
The ratio of the mass percent of the compound of formula (I) to the mass percent of the lithium salt additive, a/C, generally affects the high temperature storage performance, the high temperature intermittent cycle performance and the normal temperature cycle performance of the lithium ion battery, and it can be seen from examples 4-5 to 4-14 that when a/C is within the scope of the present application, the storage time of the lithium ion battery at 60 ℃ is longer, the number of high temperature intermittent cycle numbers and the number of normal temperature cycle numbers are more, i.e., the lithium ion battery has better high temperature storage performance, high temperature intermittent cycle performance and normal temperature cycle performance.
As can be seen from examples 4-5, examples 3-7 and comparative example 4-1, the lithium ion battery has less high temperature intermittent cycle number and normal temperature cycle number when the electrolyte of the lithium ion battery includes only the compound of formula (I) or only the lithium salt additive; when the electrolyte of the lithium ion battery simultaneously comprises the compound shown in the formula (I) and the lithium salt additive, the lithium ion battery has longer storage time at 60 ℃, more high-temperature intermittent cycle numbers and more normal-temperature cycle numbers, namely the lithium ion battery has better high-temperature intermittent cycle performance and normal-temperature cycle performance, and has good high-temperature storage performance.
It should be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments.
The foregoing is merely a preferred embodiment of the present application, and is not intended to limit the scope of the present application. Any modifications, equivalent substitutions, improvements, etc. that are within the spirit and principles of the present application are intended to be included within the scope of the present application.
Claims (12)
1. An electrolyte comprising a compound of formula (I):
wherein X is selected from CR 6 Or N;
R 1 、R 2 and R is 3 Each independently selected from hydrogen atom, halogen, C 2 -C 5 Carbonyl group, C of (2) 1 -C 5 C which is unsubstituted or substituted by Ra 1 -C 5 Alkyl, C unsubstituted or substituted by Ra 2 -C 5 Alkenyl, unsubstituted or substituted C with Ra 2 -C 5 Alkynyl, unsubstituted or substituted with Ra for C 3 -C 5 N-heterocycloalkyl, C 3 -C 5 N heteroaryl of (a); r is R 4 、R 5 And R is 6 Each independently selected from hydrogen atoms, C 1 -C 5 Alkylthio, C 2 -C 5 Sulfide, C 3 -C 5 N-heterocycloalkyl, C 3 -C 5 N heteroaryl of (2), unsubstituted or substituted by RaC of (2) 1 -C 5 Alkyl, C unsubstituted or substituted by Ra 2 -C 5 Alkenyl, unsubstituted or substituted C with Ra 2 -C 5 Alkynyl of (a); the substituents Ra of the individual radicals are each independently selected from halogen, C 1 -C 5 Aldehyde group, C 2 -C 5 Carbonyl group, C of (2) 2 -C 5 Ester group, sulfonic acid group, amino group, C 2 -C 5 Amide, cyano or anhydride;
the electrolyte further comprises a carboxylate; based on the mass of the electrolyte, the mass percentage of the compound of the formula (I) is A%, A is more than or equal to 0.01 and less than or equal to 5, and the mass percentage of the carboxylic ester is B%, and B is more than or equal to 10 and less than or equal to 70; A/B is more than or equal to 0.0005 and less than or equal to 0.4.
2. The electrolyte of claim 1, wherein R 1 、R 2 And R is 3 Each independently selected from hydrogen atom, halogen, formaldehyde, acetaldehyde, ethylene carbonyl, propylene carbonyl, methyl, ethyl, propyl, butyl, vinyl, propenyl, butenyl, ethynyl, propynyl, butynyl, pyrrole, or pyridyl; r is R 4 、R 5 And R is 6 Each independently selected from the group consisting of hydrogen, methylthio, dimethyl sulfide, methyl, ethyl, propyl, butyl, ethenyl, propenyl, butenyl, ethynyl, propynyl, butynyl, pyrrolyl, and pyridyl.
3. The electrolyte of claim 1, wherein the compound of formula (I) comprises at least one of the following compounds:
4. the electrolyte according to claim 1, wherein 0.1.ltoreq.A.ltoreq.3.
5. The electrolyte of claim 1, wherein the carboxylic acid ester comprises at least one of ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, or butyl propionate.
6. The electrolyte according to claim 5, wherein 0.0075. Ltoreq.A/B.ltoreq.0.2.
7. The electrolyte of claim 5, wherein the electrolyte further comprises an ester additive comprising at least one of ethylene carbonate, 1, 3-propane sultone, or fluoroethylene carbonate; based on the mass of the electrolyte, the mass percentage of the ester additive is D, and D is more than or equal to 0.5 and less than or equal to 18.
8. The electrolyte according to claim 5 or 7, wherein the electrolyte further comprises a nitrile compound, the nitrile compounds include malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelic dinitrile, suberonitrile, sebaconitrile, 3 '-oxydiproponitrile, hex-2-enedinitrile, fumaric dinitrile, 2-pentenenitrile, methylglutaronitrile, 4-cyanopimelic dinitrile, (Z) -but-2-enedinitrile, 2, 3-tetrafluorobutanedinitrile ethylene glycol bis (propionitrile) ether, 1,3, 5-valeronitrile, 1,3, 6-capro-tril, 1,2, 3-tris (2-cyanooxy) propane, 1, 3-propanetetracarbonitrile at least one of 2,2' - (1, 4-phenylene) dipropylene dinitrile, 1, 5-pentylternanitrile, 1, 4-butyltetranitrile, or 1, 6-hexyltetranitrile; based on the mass of the electrolyte, the mass percentage of the nitrile compound is E.ltoreq.E.ltoreq.8.
9. The electrolyte of claim 8, wherein the electrolyte comprises a lithium salt additive comprising at least one of lithium difluorophosphate, lithium tetrafluoroborate, lithium trifluoromethanesulfonyl imide, lithium bistrifluoromethanesulfonimide, lithium bisoxalato borate, or lithium difluorooxalato borate; based on the mass of the electrolyte, the mass percentage of the lithium salt additive is C.0.01-4.
10. The electrolyte of claim 9, wherein 0.1-30 a/C.
11. An electrochemical device comprising the electrolyte of any one of claims 1 to 10.
12. An electronic device comprising the electrochemical device of claim 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310219108.9A CN115966770B (en) | 2023-03-09 | 2023-03-09 | Electrolyte, electrochemical device and electronic device comprising same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310219108.9A CN115966770B (en) | 2023-03-09 | 2023-03-09 | Electrolyte, electrochemical device and electronic device comprising same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115966770A CN115966770A (en) | 2023-04-14 |
| CN115966770B true CN115966770B (en) | 2023-06-02 |
Family
ID=85888658
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310219108.9A Active CN115966770B (en) | 2023-03-09 | 2023-03-09 | Electrolyte, electrochemical device and electronic device comprising same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115966770B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110931862A (en) * | 2019-10-31 | 2020-03-27 | 合肥国轩高科动力能源有限公司 | Difunctional electrolyte additive and lithium ion battery electrolyte containing same |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6767671B2 (en) * | 2000-07-14 | 2004-07-27 | Mitsubishi Chemical Corporation | Non-aqueous electrolytic solution and secondary battery containing same |
| WO2014168165A1 (en) * | 2013-04-12 | 2014-10-16 | 富士フイルム株式会社 | Photoelectric conversion element, dye-sensitized solar cell, metal-complex dye, dye solution, dye-adsorbed electrode, and method for manufacturing dye-sensitized solar cell |
| KR102059223B1 (en) * | 2015-05-14 | 2019-12-24 | 주식회사 엘지화학 | Non-aqueous electrolyte solution and secondary battery comprising the same |
| CN111244543A (en) * | 2020-01-15 | 2020-06-05 | 松山湖材料实验室 | High-voltage lithium ion battery electrolyte additive, electrolyte, battery and formation method thereof |
| CN115332638B (en) * | 2022-10-14 | 2023-03-24 | 宁德新能源科技有限公司 | Electrolyte, electrochemical device and electronic device |
-
2023
- 2023-03-09 CN CN202310219108.9A patent/CN115966770B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110931862A (en) * | 2019-10-31 | 2020-03-27 | 合肥国轩高科动力能源有限公司 | Difunctional electrolyte additive and lithium ion battery electrolyte containing same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115966770A (en) | 2023-04-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111342135B (en) | Electrochemical device and electronic device comprising same | |
| CN111525191B (en) | Electrolyte and electrochemical device | |
| CN113809399B (en) | Electrolyte, electrochemical device and electronic device comprising same | |
| CN112400249A (en) | Electrolyte and electrochemical device | |
| CN114068910A (en) | Electrochemical device and electronic device | |
| CN109830749B (en) | Electrolyte and electrochemical device | |
| CN113241478B (en) | Electrolyte solution, electrochemical device, and electricity-consuming apparatus | |
| WO2023216473A1 (en) | Electrochemical apparatus and electronic apparatus | |
| CN116097471A (en) | Electrochemical device and electronic device comprising same | |
| CN109994778B (en) | Electrolyte solution and secondary battery | |
| CN112005418A (en) | Electrolyte and electrochemical device | |
| CN117913220A (en) | Secondary battery and electricity utilization device comprising same | |
| CN111697267A (en) | Electrolyte solution, electrochemical device containing electrolyte solution, and electronic device | |
| CN116053591B (en) | Electrolyte of secondary battery, secondary battery and electronic device | |
| CN116741941A (en) | Electrode assembly, electrochemical device and electricity utilization device | |
| CN115966770B (en) | Electrolyte, electrochemical device and electronic device comprising same | |
| CN111600065A (en) | Electrolyte solution and electrochemical device using the same | |
| CN115954547B (en) | Electrolyte, electrochemical device and electronic device | |
| CN115986210B (en) | Electrochemical device and electronic device | |
| CN113889664B (en) | Electrolyte, electrochemical device, and electronic device | |
| CN114628787B (en) | Electrolyte, electrochemical device, and electronic device | |
| CN112886061B (en) | Electrolyte and electrochemical device containing same | |
| CN117577959A (en) | Electrochemical device and electronic device | |
| CN115832429A (en) | Electrolyte, electrochemical device and electronic device | |
| CN116706232A (en) | Electrolyte of secondary battery, secondary battery and electronic device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |