CN108242556B - Electrolyte solution and secondary battery - Google Patents
Electrolyte solution and secondary battery Download PDFInfo
- Publication number
- CN108242556B CN108242556B CN201611218759.2A CN201611218759A CN108242556B CN 108242556 B CN108242556 B CN 108242556B CN 201611218759 A CN201611218759 A CN 201611218759A CN 108242556 B CN108242556 B CN 108242556B
- Authority
- CN
- China
- Prior art keywords
- electrolyte
- compound
- carbonate
- secondary battery
- group
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides an electrolyte and a secondary battery. The electrolyte includes an electrolyte salt, an organic solvent, and an additive. The organic solvent includes a carboxylic acid ester compound. The additive comprises a dinitrile compound, an aromatic compound overcharge additive and fluoroethylene carbonate and/or vinylene carbonate. When the electrolyte is applied to a secondary battery, the rate capability, the normal-temperature cycle performance, the high-temperature storage performance and the overcharge safety performance of the secondary battery can be improved.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to an electrolyte and a secondary battery.
Background
In the rapidly developing information age, the demand for electronic products such as mobile phones, notebooks, cameras, and the like has increased year by year. The secondary battery, especially the lithium ion secondary battery, is used as the working power supply of electronic products, has the characteristics of high energy density, no memory effect, high working voltage and the like, and is gradually replacing the traditional Ni-Cd and MH-Ni batteries. However, with the expansion of market demand of electronic products and the development of power and energy storage devices, the demand of people for secondary batteries is continuously increasing, and it is urgent to develop a secondary battery having high energy density and satisfying rapid charging and discharging. Currently, effective methods are to increase the voltage, the compaction density, and select a suitable electrolyte for the electrode active material.
Currently, the electrolyte widely used in the lithium ion secondary battery includes an electrolyte using lithium hexafluorophosphate as an electrolyte salt and a mixture of cyclic carbonate and chain carbonate as an organic solvent, but the above electrolyte has many disadvantages, particularly, the cycle performance, high-temperature storage performance, safety performance and rate capability of the secondary battery are poor at a high voltage.
Disclosure of Invention
In view of the problems of the background art, an object of the present invention is to provide an electrolyte and a secondary battery, which can improve rate capability, normal temperature cycle capability, high temperature storage capability, and overcharge safety capability of the secondary battery when applied to the secondary battery.
In order to achieve the above object, in one aspect of the present invention, there is provided an electrolyte comprising: electrolyte, organic solvent and additive. The organic solvent includes a carboxylic acid ester compound. The additive comprises a dinitrile compound, an aromatic compound overcharge additive and fluoroethylene carbonate and/or vinylene carbonate.
In another aspect of the present invention, the present invention provides a secondary battery including the electrolyte according to one aspect of the present invention.
Compared with the prior art, the beneficial effects of the invention include, but are not limited to:
when the electrolyte is applied to a secondary battery, the rate performance, the normal-temperature cycle performance, the high-temperature storage performance and the overcharge safety performance of the secondary battery can be improved.
Detailed Description
The electrolyte and the secondary battery according to the present invention will be described in detail below.
First, the electrolytic solution according to the first aspect of the invention is explained.
The electrolytic solution according to the first aspect of the invention includes an electrolyte salt, an organic solvent, and an additive. The organic solvent includes a carboxylic acid ester compound. The additive comprises a dinitrile compound, an aromatic compound overcharge additive and fluoroethylene carbonate and/or vinylene carbonate.
In the electrolytic solution according to the first aspect of the invention, the carboxylate compound is used to improve the rate performance of the secondary battery, but when the carboxylate compound is applied to a secondary battery of a high voltage system, it is easily decomposed by oxidation, and in addition, when the secondary battery using the carboxylate compound is used under a high temperature environment, the capacity loss of the secondary battery after many cycles is serious, and the high temperature storage performance of the secondary battery is seriously deteriorated. The dinitrile compound can be complexed with the anode of the secondary battery, the dynamic performance of the secondary battery is reduced while the interface side reaction at high temperature is reduced, meanwhile, the dinitrile compound has stronger electron-withdrawing characteristic, electrons are easy to obtain at the cathode to carry out reduction reaction, and the product obtained by reduction is unstable and can be deposited on the cathode, thereby influencing the normal-temperature cycle performance and the rate capability of the secondary battery. Fluoroethylene carbonate and/or vinylene carbonate can preferentially form a film on the surface of a negative electrode, and the reduction of a carboxylic ester compound and the side reaction of a dinitrile compound are inhibited, so that the normal-temperature cycle performance of the secondary battery is improved. The aromatic compound overcharge additive may improve overcharge safety performance of the secondary battery, but when the content thereof is increased, viscosity of the electrolyte is increased to deteriorate kinetic performance of the secondary battery. When the carboxylate compound, the dinitrile compound, the aromatic compound overcharge additive and the fluoroethylene carbonate and/or vinylene carbonate are simultaneously added into the electrolyte, the rate performance, the high-temperature storage performance, the normal-temperature cycle performance and the overcharge safety performance of the secondary battery can be simultaneously improved under the synergistic action of the above substances.
In the electrolyte according to the first aspect of the present invention, the carboxylate compound is one or more selected from compounds represented by formula 1. In formula 1, R1、R2Each independently selected from one of C1-10 alkyl and C1-10 halogenated alkyl. Wherein, the halogen atom in the alkyl halide is selected from one or more of F, Cl, Br and I.
In the electrolyte according to the first aspect of the present invention, the alkyl group having 1 to 10 carbon atoms may be a chain alkyl group or a cyclic alkyl group. Among them, the chain alkyl group includes a straight chain alkyl group and a branched chain alkyl group. The cyclic alkyl group may or may not have a substituent. In the above-mentioned alkyl group, the lower limit of the number of carbon atoms may be preferably 1,2 or 3, and the upper limit of the number of carbon atoms may be preferably 4, 5, 6, 7, 8, 9 or 10. Preferably, R1、R2Each independently selected from a chain alkyl group having 1 to 6 carbon atoms or a cyclic alkyl group having 3 to 8 carbon atoms. Even more preferably, R1、R2Each independently selected from a chain alkyl group having 1 to 4 carbon atoms or a cyclic alkyl group having 5 to 7 carbon atoms.
Specifically, the alkyl group having 1 to 10 carbon atoms may be one selected from the group consisting of a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a cyclopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a cyclobutyl group, a n-pentyl group, an isopentyl group, a tert-pentyl group, a neopentyl group, a cyclopentyl group, a2, 2-dimethylpropyl group, a 1-ethylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a n-hexyl group, an isohexyl group, a 2-hexyl group, a 3-hexyl group, a cyclohexyl group, a 2-methylpentyl group, a 3-methylpentyl group, a1, 1, 2-trimethylpropyl group, a 3, 3-dimethylbutyl group, a n-heptyl group, a 2-heptyl group, a 3-heptyl group, a 2-methylhexyl group, a 3-.
In the electrolyte solution according to the first aspect of the present invention, the number of substitution of halogen atoms in the halogenated alkyl group having 1 to 10 carbon atoms and the substitution position thereof are not particularly limited and may be selected according to actual needs. Specifically, the number of halogen atoms may be 1,2, 3 or 4. When the number of halogen atoms is 2 or more, the halogen atoms may be the same, may be completely different, or may be partially the same. The alkyl halide may be a chain alkyl halide or a cyclic alkyl halide. The chain halogenated alkyl groups further include straight chain halogenated alkyl groups and branched chain halogenated alkyl groups. The cyclic alkyl halide group may or may not have a substituent. In the haloalkane group, the number of carbon atoms may be preferably lower than 1,2 or 3, and the number of carbon atoms may be preferably upper than 4, 5, 6, 7, 8, 9 or 10. Preferably, R1、R2Each independently selected from a chain alkyl halide having 1 to 6 carbon atoms or a cyclic alkyl halide having 3 to 8 carbon atoms. Even more preferably, R1、R2Each independently selected from a chain alkyl halide having 1 to 4 carbon atoms or a cyclic alkyl halide having 5 to 7 carbon atoms.
Specifically, the alkyl halide having 1 to 10 carbon atoms is selected from the group consisting of chloromethyl, dichloromethyl, trichloromethyl, 1-chloroethyl, 1, 2-dichloroethyl, 2-chloro-n-propyl, 2-dichloro-n-propyl, 1-chloroisopropyl, monochloropropyl, 1-chloro-n-butyl, 2-chloroisobutyl, monochlorocyclobutyl, 1-chloro-n-pentyl, 2-chloro-n-pentyl, 1-chloroisopentyl, 2-dichloromethylpropyl, monochlorocyclopentyl, 3-chloro-2, 2-dimethylpropyl, 1-chloro-1-ethylpropyl, 1-chloro-1-methylbutyl, 2-chloro-2-methylbutyl, 2-chloro-n-hexyl, monochlorocyclohexyl, 2-chloromethylpentyl, chlorocyclohexyl, chlorocyclopentyl, chlorobutyl, 3-chloro-3-methylpentyl, 2-chloro-1, 1, 2-trimethylpropyl, 4-chloro-3, 3-dimethylbutyl, 2-chloro-n-heptyl. In the above groups, the Cl atom in the alkyl halide group can be partially or completely substituted by one or more of F, Br and I.
In the electrolyte according to the first aspect of the present invention, the carboxylate compound may be selected from one or more of methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, isobutyl propionate, pentyl propionate, isoamyl propionate, ethyl isopropionate, ethyl butyrate, ethyl isobutyrate, butyl butyrate, butyl isobutyrate, pentyl butyrate, isoamyl butyrate, ethyl valerate, ethyl isovalerate, propyl valerate, propyl isovalerate, and a compound in which the above carboxylate compound is partially or fully substituted with one or more of F, Cl, Br, and I. Preferably, the carboxylate compound is selected from methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate and one or more of the compounds of the carboxylate compounds, wherein the compounds are partially or completely substituted by one or more of F, Cl, Br and I.
In the electrolyte according to the first aspect of the invention, the dinitrile compound is selected from one or more compounds represented by formula 2. In formula 2, R3One selected from alkylene with 1-20 carbon atoms, halogenated alkylene with 1-20 carbon atoms, alkyleneoxy with 1-20 carbon atoms, halogenated alkyleneoxy with 1-20 carbon atoms, alkylene with 2-20 carbon atoms and halogenated alkylene with 2-20 carbon atoms, wherein halogen atoms are selected from one or more of F, Cl, Br and I.
NC-R3-CN formula2
In the electrolyte according to the first aspect of the present invention, preferably, R3Selected from the group consisting of C1-10 alkylene group, C1-10 halogenated alkylene group, and C1-10 alkyleneoxy groupOne of C1-10 haloalkylene oxy, C2-10 alkenylene and C2-10 haloalkenylene, wherein the halogen atom is selected from one or more of F, Cl and Br.
In the electrolyte solution according to the first aspect of the present invention, the number of oxygen atoms in the alkyleneoxy group or the haloalkyleneoxy group may be 1,2, or more.
In the electrolyte according to the first aspect of the present invention, the dinitrile compound is selected from the group consisting of malononitrile, succinonitrile, 2-methylsuccinonitrile, tetramethylsuccinonitrile, glutaronitrile, 2-methylglutaronitrile, adiponitrile, fumarodinitrile, 2-methyleneglutaronitrile, 3, 5-dioxa-pimelinonitrile, ethylene glycol di (2-cyanoethyl) ether, diethylene glycol di (2-cyanoethyl) ether, triethylene glycol di (2-cyanoethyl) ether, tetraethylene glycol di (2-cyanoethyl) ether, 1, 2-bis (2-cyanoethoxy) ethane, 1, 3-bis (2-cyanoethoxy) propane, 1, 4-bis (2-cyanoethoxy) butane, 1, 5-bis (2-cyanoethoxy) pentane, ethylene glycol di (4-cyanobutyl) ether, ethylene glycol di (2-cyanoethoxy) ether, and mixtures thereof, 1, 6-dicyano hexane and 1, 2-dibromo-2, 4-dicyano butane.
In the electrolyte according to the first aspect of the present invention, the aromatic compound overcharge additive is one or more selected from biphenyl, cyclohexylbenzene, toluene, xylene, fluorobenzene, tert-butylbenzene, and tert-amylbenzene.
In the electrolytic solution according to the first aspect of the invention, the volume of the carboxylate compound is 5% to 50% of the total volume of the organic solvent. Preferably, the volume of the carboxylate compound is 10% to 40% of the total volume of the organic solvent. Further preferably, the volume of the carboxylate compound is 20% to 35% of the total volume of the organic solvent.
In the electrolyte according to the first aspect of the invention, the content of the dinitrile compound is 0.5% to 10% by weight of the total weight of the electrolyte. Preferably, the content of the dinitrile compound is 1% to 5% of the total weight of the electrolyte.
In the electrolyte according to the first aspect of the present invention, the aromatic compound overcharge additive is contained in an amount of 0.5 to 15% by weight based on the total weight of the electrolyte. Preferably, the content of the aromatic compound overcharge additive is 1 to 5% of the total weight of the electrolyte.
In the electrolyte according to the first aspect of the present invention, the total content of fluoroethylene carbonate and/or vinylene carbonate is 0.05-12% of the total weight of the electrolyte.
In the electrolyte according to the first aspect of the present invention, preferably, the fluoroethylene carbonate is contained in an amount of 0.5% to 10% based on the total weight of the electrolyte. More preferably, the fluoroethylene carbonate is present in an amount of 1% to 5% based on the total weight of the electrolyte.
In the electrolyte according to the first aspect of the present invention, preferably, the content of the vinylene carbonate is 0.05% to 5% of the total weight of the electrolyte. Further preferably, the content of the vinylene carbonate is 0.2-1% of the total weight of the electrolyte.
In the electrolytic solution according to the first aspect of the invention, the electrolyte salt may be selected from a lithium salt, a sodium salt, or a zinc salt, depending on the secondary battery to which the electrolytic solution is applied.
In the electrolytic solution according to the first aspect of the invention, the content of the electrolyte salt is 6.2% to 25% by weight of the total weight of the electrolytic solution. Preferably, the content of the electrolyte salt is 6.25 to 18.8% of the total weight of the electrolyte. Further preferably, the content of the electrolyte salt is 10% to 15% of the total weight of the electrolyte.
In the electrolyte according to the first aspect of the present invention, the specific type of the organic solvent is not particularly limited, and may be selected according to actual needs. Preferably, a non-aqueous organic solvent is used. The non-aqueous organic solvent may include any kind of carbonate and a halogenated compound of the carbonate. The carbonate may include cyclic carbonates and chain carbonates. Specifically, the organic solvent may be selected from one or more of Ethylene Carbonate (EC), Propylene Carbonate (PC), butylene carbonate, pentylene carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, Ethyl Methyl Carbonate (EMC), γ -Butyrolactone (BL), and Tetrahydrofuran (THF).
In the electrolyte according to the first aspect of the present invention, the electrolyte may be prepared by a conventional method, for example, by uniformly mixing the materials in the electrolyte.
Next, a secondary battery according to a second aspect of the invention is explained.
A secondary battery according to a second aspect of the invention includes the electrolyte according to the first aspect of the invention.
In the secondary battery according to the second aspect of the invention, the secondary battery further includes: positive plate, negative plate and barrier film. The positive plate comprises a positive current collector and a positive diaphragm arranged on the positive current collector, and the positive diaphragm comprises a positive active material, a bonding agent and a conductive agent. The negative plate comprises a negative current collector and a negative diaphragm arranged on the negative current collector, wherein the negative diaphragm comprises a negative active material and a bonding agent, and can also comprise a conductive agent. The isolating film is arranged between the positive plate and the negative plate.
In the secondary battery according to the second aspect of the present invention, the separator may be any separator material used in existing secondary batteries, such as, but not limited to, polyethylene, polypropylene, polyvinylidene fluoride, and multilayer composite films thereof.
In the secondary battery according to the second aspect of the invention, the secondary battery may be a lithium ion secondary battery, a sodium ion secondary battery, or a zinc ion secondary battery.
When the secondary battery is a lithium ion secondary battery, the electrolyte salt may be selected from a lithium salt, and the lithium salt may be selected from LiPF6、LiBF4、LiFSI、LiTFSI、LiClO4、LiAsF6、LiBOB、LiDFOB、LiPO2F2、LiTFOP、LiN(SO2RF)2、LiN(SO2F)(SO2RF), wherein RF ═ CnF2n+1It represents a saturated perfluoroalkyl group, and n is an integer of 1 to 10. Preferably, the lithium salt is LiPF6。
When the secondary battery is a lithium ion secondary battery, the positive active material may be selected from lithium cobaltate (LiCoO)2) Lithium nickelate (LiNiO)2) Spinel type LiMn2O4Olivine type LiMPO4Ternary positive electrode material LiNixAyB(1-x-y)O2And Li1-x’(A’y’B’z’C1-y’-z’)O2One or more of them. Wherein the olivine type LiMPO4In the formula, M is selected from one or more of Co, Ni, Fe, Mn and V; in a ternary positive electrode material LiNixAyB(1-x-y)O2A, B is independently selected from one of Co, Al and Mn, A and B are different, 0<x<1，0<y<1 and x + y<1; in the ternary cathode material Li1-x’(A’y’B’z’C1-y’-z’)O2In the formula, A ', B' and C are respectively and independently selected from one of Co, Ni, Fe and Mn, 0<x’<1，0≤y’<1，0≤z’<1 and y '+ z'<1, and A ', B' and C are different.
When the secondary battery is a lithium ion secondary battery, the anode active material may be selected from metallic lithium. The negative active material may also be selected from < 2V (vs. Li/Li)+) A material that can intercalate lithium, and specifically, the negative active material may be selected from natural graphite, artificial graphite, mesophase micro carbon spheres (abbreviated as MCMB), hard carbon, soft carbon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO2Spinel-structured lithiated TiO2-Li4Ti5O12And one or more of Li-Al alloy.
When the secondary battery is a sodium ion secondary battery or a zinc ion secondary battery, only the corresponding positive electrode active material, negative electrode active material and electrolyte salt need to be changed.
The present application is further illustrated below with reference to examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present application. In the embodiment, only the case where the secondary battery is a lithium ion secondary battery is shown, but the present invention is not limited thereto.
In the following examples, materials, reagents and instruments used were commercially available, unless otherwise specified.
For ease of illustration, the additives used in the following examples are abbreviated as follows:
a1: propionic acid ethyl ester
A2: propylpropionate
B1: adiponitrile
B2: succinonitrile and its use
C1: biphenyl
C2: tert-butyl benzene
D1: fluoroethylene carbonate
D2: vinylene carbonate
The lithium ion secondary batteries of examples 1 to 17 and comparative examples 1 to 15 were each prepared as follows.
(1) Preparation of positive plate
The positive electrode active material lithium cobaltate (LiCoO)2) Mixing polyvinylidene fluoride serving as a bonding agent and acetylene black serving as a conductive agent according to a weight ratio of 96:2:2, adding N-methyl pyrrolidone (NMP), and stirring under the action of a vacuum stirrer until a system becomes uniform and transparent to obtain anode slurry; uniformly coating the positive electrode slurry on a positive electrode current collector aluminum foil with the thickness of 12 mu m; and (3) airing the aluminum foil at room temperature, transferring the aluminum foil to a 120 ℃ oven for drying for 1h, and then performing cold pressing and slitting to obtain the positive plate.
(2) Preparation of negative plate
Mixing the negative active material artificial graphite, the thickener sodium carboxymethyl cellulose (CMC) and the binder styrene butadiene rubber according to the weight ratio of 97:1:2, adding the mixture into deionized water, and obtaining negative slurry under the stirring action of a vacuum stirrer; uniformly coating the negative electrode slurry on a negative electrode current collector copper foil with the thickness of 8 mu m; and (3) airing the copper foil at room temperature, transferring the copper foil to a 120 ℃ oven for drying for 1h, and then performing cold pressing and slitting to obtain the negative plate.
(3) Preparation of electrolyte
At water content<In a 10ppm argon atmosphere glove box, EC, PC and DEC are calculated according to the volume ratio of EC to PCPC: DEC ═ 1:1:1, followed by thoroughly drying the lithium salt LiPF6Dissolving the electrolyte in a mixed organic solvent, adding a carboxylic ester compound, a dinitrile compound, an aromatic compound overcharge additive and fluoroethylene carbonate and/or vinylene carbonate, and uniformly mixing to obtain the electrolyte. Wherein, LiPF6The content of (b) was 12.5% by weight of the total electrolyte. Specific kinds and contents of the carboxylate compound, dinitrile compound, aromatic compound overcharge additive, fluoroethylene carbonate and vinylene carbonate used in the electrolyte are shown in table 1. In table 1, the content of the carboxylic acid ester compound is a volume percentage calculated based on the total volume of the organic solvent, and the content of the dinitrile compound, the aromatic compound overcharge additive, the fluoroethylene carbonate, and the vinylene carbonate is a weight percentage calculated based on the total weight of the electrolyte.
(4) Preparation of the separator
A16 μm thick polypropylene separator (type C210, supplied by Celgard) was used.
(5) Preparation of lithium ion secondary battery
Stacking the positive plate, the isolating film and the negative plate in sequence to enable the isolating film to be positioned between the positive plate and the negative plate to play an isolating role, and then winding to obtain a bare cell; placing a bare cell in an outer packaging foil, after the cell is stood at a high temperature of 75 ℃ for 24 hours, and the water content of the cell meets the specification, injecting the prepared electrolyte into the dried bare cell, and performing vacuum packaging, standing, formation, shaping and other procedures, thereby obtaining the lithium ion secondary battery.
TABLE 1 parameters for examples 1-17 and comparative examples 1-15
Note: "-" indicates no addition.
Next, a test procedure of the lithium ion secondary battery is explained.
(1) Rate capability test of lithium ion secondary battery
At 25 ℃, the lithium ion secondary battery is charged to a voltage of 4.3V by a constant current of 1C (nominal capacity), then charged to a current of less than or equal to 0.05C by a constant voltage of 4.3V, and after standing for 5min, discharged to a cut-off voltage of 3V by a constant current of 0.2C, and the actual discharge capacity is recorded as D0.
And then charging the lithium ion secondary battery to a voltage of 4.3V at a constant current of 1C, then charging to a current of less than or equal to 0.05C at a constant voltage of 4.3V, standing for 5min, and then discharging to a cut-off voltage of 3V at a constant current of 2C, wherein the discharge capacity at the moment is marked as D1.
The lithium ion secondary battery 2C/0.2C rate performance is D1/D0 × 100%. Each group was tested for 15 lithium ion secondary batteries and the average was taken.
(2) Normal temperature cycle performance test of lithium ion secondary battery
At 25 ℃, the lithium ion secondary battery is charged to a voltage of 4.3V at a constant current of 1C, then charged to a current of 0.05C at a constant voltage, and then discharged to a voltage of 3.0V at a constant current of 1C, which is a charge-discharge cycle process, and the discharge capacity of the current is the discharge capacity of the first cycle. The lithium ion secondary battery was subjected to 300-cycle charge/discharge tests in accordance with the above-described method, and the discharge capacity at the 300 th cycle was detected.
Capacity retention (%) of the lithium ion secondary battery after 300 cycles at 25 ℃ ═ 100% (discharge capacity of the lithium ion secondary battery after 300 cycles/discharge capacity of the lithium ion secondary battery after the first cycle). Each group was tested for 15 lithium ion secondary batteries and the average was taken.
(3) High temperature storage performance test of lithium ion secondary battery
The lithium ion secondary battery was charged at 25 ℃ at a constant current of 0.5C to a voltage of 4.3V and then at a constant voltage of 4.3V to a current of 0.05C, and the thickness of the lithium ion secondary battery was measured and recorded as h0(ii) a Then the lithium ion secondary battery is placed into a constant temperature box with the temperature of 60 ℃, is taken out after being stored for 30 days, and the thickness of the lithium ion secondary battery is tested and recorded as h1。
Thickness expansion rate [ (h) of lithium ion secondary battery after 30 days of storage at 60 ℃1-h0)/h0]X 100%. Each group was tested for 15 lithium ion secondary batteries and the average was taken.
(4) Overcharge safety performance test of lithium ion secondary battery
The state of the lithium ion secondary battery was observed at 25 ℃ by constant-current charging the lithium ion secondary battery at 3C (nominal capacity) to a voltage of 7.5V, followed by continuing constant-voltage charging at 7.5V for 5 h. And calculating the passing rate of the lithium ion secondary battery by taking the non-ignition, non-combustion and non-explosion as judgment standards.
TABLE 2 test results of examples 1 to 17 and comparative examples 1 to 15
It can be known from the analysis of the related data in table 2 that the electrolyte of the present invention can simultaneously improve the normal temperature cycle performance, the high temperature storage performance, the rate performance and the overcharge safety performance of the lithium ion secondary battery when applied to the lithium ion secondary battery.
In comparative example 2 in which only the carboxylate compound was added, the rate performance of the lithium ion secondary battery was improved, but the normal temperature cycle performance and the high temperature storage performance were deteriorated. In comparative example 3, only the dinitrile compound was added, the high-temperature storage property could be improved, but the rate property and the normal-temperature cycle property were somewhat deteriorated. The addition of only the aromatic compound overcharge additive in comparative example 4 can improve the overcharge safety performance, but other properties are deteriorated. The addition of fluoroethylene carbonate in comparative example 5 can improve normal temperature cycle properties but deteriorate high temperature storage properties. In comparative example 6, the addition of both the carboxylate compound and the dinitrile compound improved the high-temperature storage property while improving the rate property, but the normal-temperature cycle property was deteriorated. In comparative example 7, the carboxylic acid ester compound and the aromatic compound overcharge additive were simultaneously added, so that both the rate capability and the overcharge safety performance were considered, but the normal temperature cycle performance and the high temperature storage performance were deteriorated. In comparative example 8, in which the carboxylate compound and fluoroethylene carbonate were simultaneously added, rate performance and normal temperature cycle performance were improved, but high temperature storage performance was deteriorated. In comparative example 9, the simultaneous addition of dinitrile compound and aromatic compound overcharge additive improved high-temperature storage performance and overcharge safety performance, but rate performance and normal-temperature cycle performance were deteriorated. The simultaneous addition of dinitrile compound and fluoroethylene carbonate in comparative example 10 can improve high-temperature storage properties and normal-temperature cycle properties, but the rate properties are poor. The simultaneous addition of the aromatic compound overcharge additive and fluoroethylene carbonate in comparative example 11 can improve the normal temperature cycle property and the overcharge safety property, but deteriorate the high temperature storage property. The simultaneous addition of the carboxylate compound, dinitrile compound and aromatic compound overcharge additive in comparative example 12 can improve rate properties, high-temperature storage properties and overcharge safety properties, but the normal-temperature cycle properties are deteriorated. The simultaneous addition of the carboxylate compound, the dinitrile compound and the fluoroethylene carbonate in comparative example 13 can improve rate performance, high-temperature storage performance and normal-temperature cycle performance, but the lithium ion secondary battery cannot pass the overcharge test. The simultaneous addition of the carboxylic acid ester compound, the aromatic compound overcharge additive and the fluoroethylene carbonate in comparative example 14 can improve rate property, overcharge safety property and normal temperature cycle property, but deteriorate high temperature storage property. The simultaneous addition of dinitrile compound, aromatic compound overcharge additive and fluoroethylene carbonate in comparative example 15 can improve high-temperature storage property, overcharge safety property and normal-temperature cycle property, but rate property is deteriorated.
Claims (13)
1. An electrolyte, comprising:
an electrolyte salt;
an organic solvent; and
an additive;
it is characterized in that the preparation method is characterized in that,
the organic solvent includes a carboxylic acid ester compound;
the additive comprises:
a dinitrile compound;
an aromatic overcharge additive; and
fluoroethylene carbonate and/or vinylene carbonate;
the volume of the carboxylic ester compound is 5-20% of the total volume of the organic solvent;
the content of the dinitrile compound is 0.5-10% of the total weight of the electrolyte;
the content of the aromatic compound overcharge additive is 0.5-15% of the total weight of the electrolyte;
the total content of the fluoroethylene carbonate and/or vinylene carbonate is 0.05-12% of the total weight of the electrolyte.
2. The electrolyte of claim 1, wherein the carboxylate compound is selected from one or more compounds represented by formula 1;
wherein the content of the first and second substances,
R1、R2each independently selected from one of C1-10 alkyl and C1-10 halogenated alkyl;
the halogen atom in the halogenated alkyl group is selected from one or more of F, Cl, Br and I.
3. The electrolyte of claim 2, wherein the carboxylate compound is selected from the group consisting of methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, isobutyl propionate, pentyl propionate, isopentyl propionate, ethyl isopropionate, ethyl butyrate, ethyl isobutyrate, butyl butyrate, butyl isobutyrate, pentyl butyrate, isopentyl butyrate, ethyl valerate, ethyl isovalerate, propyl valerate, propyl isovalerate, and one or more compounds in which the carboxylate compound is partially or fully substituted with one or more of F, Cl, Br, and I.
4. The electrolyte according to claim 3, wherein the carboxylate compound is selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and one or more of the foregoing carboxylate compounds partially or fully substituted with one or more of F, Cl, Br, and I.
5. The electrolyte of claim 1, wherein the dinitrile compound is selected from one or more of the compounds represented by formula 2;
NC-R3-CN formula 2
Wherein the content of the first and second substances,
R3one selected from alkylene group with 1-20 carbon atoms, halogenated alkylene group with 1-20 carbon atoms, alkyleneoxy group with 1-20 carbon atoms, halogenated alkyleneoxy group with 1-20 carbon atoms, alkylene group with 2-20 carbon atoms and halogenated alkylene group with 2-20 carbon atoms, and halogen atom is selected from one or more of F, Cl, Br and I.
6. The electrolyte of claim 5, wherein the dinitrile compound is selected from the group consisting of malononitrile, succinonitrile, 2-methyl succinonitrile, tetramethyl succinonitrile, glutaronitrile, 2-methyl glutaronitrile, adiponitrile, fumarodinitrile, 2-methylene glutaronitrile, 3, 5-dioxa-pimelonitrile, ethylene glycol di (2-cyanoethyl) ether, diethylene glycol di (2-cyanoethyl) ether, triethylene glycol di (2-cyanoethyl) ether, tetraethylene glycol di (2-cyanoethyl) ether, 1, 2-bis (2-cyanoethoxy) ethane, 1, 3-bis (2-cyanoethoxy) propane, 1, 4-bis (2-cyanoethoxy) butane, 1, 5-bis (2-cyanoethoxy) pentane, ethylene glycol di (4-cyanobutyl) ether, ethylene glycol di (2-cyanobutyl) ether, and mixtures thereof, 1, 6-dicyano hexane and 1, 2-dibromo-2, 4-dicyano butane.
7. The electrolyte of claim 1, wherein the aromatic compound overcharge additive is selected from one or more of biphenyl, cyclohexylbenzene, toluene, xylene, fluorobenzene, tert-butylbenzene, and tert-amylbenzene.
8. The electrolyte of claim 1,
the content of the dinitrile compound is 1-5% of the total weight of the electrolyte;
the content of the aromatic compound overcharge additive accounts for 1-5% of the total weight of the electrolyte.
9. The electrolyte of claim 1, wherein the electrolyte salt is present in an amount of 6.2% to 25% by weight based on the total weight of the electrolyte.
10. The electrolyte of claim 9, wherein the electrolyte salt is present in an amount of 6.25% to 18.8% by weight of the total electrolyte.
11. The electrolyte of claim 10, wherein the electrolyte salt is present in an amount of 10% to 15% by weight of the total electrolyte.
12. The electrolyte of claim 1, wherein the organic solvent further comprises one or more of ethylene carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylethyl carbonate, γ -butyrolactone, and tetrahydrofuran.
13. A secondary battery comprising the electrolyte according to any one of claims 1 to 12.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611218759.2A CN108242556B (en) | 2016-12-26 | 2016-12-26 | Electrolyte solution and secondary battery |
| PCT/CN2017/093864 WO2018120794A1 (en) | 2016-12-26 | 2017-07-21 | Electrolyte and secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611218759.2A CN108242556B (en) | 2016-12-26 | 2016-12-26 | Electrolyte solution and secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108242556A CN108242556A (en) | 2018-07-03 |
| CN108242556B true CN108242556B (en) | 2020-01-17 |
Family
ID=62701640
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611218759.2A Active CN108242556B (en) | 2016-12-26 | 2016-12-26 | Electrolyte solution and secondary battery |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN108242556B (en) |
| WO (1) | WO2018120794A1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112002942B (en) * | 2018-09-21 | 2022-08-02 | 宁德新能源科技有限公司 | Electrolyte and electrochemical device containing same |
| CN109802180B (en) * | 2019-01-25 | 2021-08-03 | 宁德新能源科技有限公司 | Electrolyte solution and electrochemical device |
| KR102633527B1 (en) * | 2019-11-18 | 2024-02-06 | 주식회사 엘지에너지솔루션 | Non-aqueous electrolyte for lithium secondary battery and lithium secondary battery comprising the same |
| US11742518B2 (en) | 2019-12-24 | 2023-08-29 | Ningde Amperex Technology Limited | Electrolyte, and electrochemical device and electronic device using the same |
| EP4037052B1 (en) * | 2019-12-24 | 2023-07-05 | Contemporary Amperex Technology Co., Limited | Secondary battery and device containing secondary battery |
| EP3985775A1 (en) * | 2020-10-16 | 2022-04-20 | Tiamat SAS | Electrolyte for na-ion battery |
| EP4260396A2 (en) * | 2020-12-11 | 2023-10-18 | Sila Nanotechnologies Inc. | Electrolytes for lithium-ion battery cells with volume-changing anode particles |
| US20230299362A1 (en) * | 2022-03-18 | 2023-09-21 | Sila Nanotechnologies, Inc. | Electrolyte compositions for lithium-ion battery cells with anodes comprising a blend of silicon-carbon composite particles and graphite particles |
| CN116802873A (en) * | 2022-05-25 | 2023-09-22 | 宁德新能源科技有限公司 | Electrochemical device and electronic device comprising same |
| CN115995553A (en) * | 2022-11-18 | 2023-04-21 | 珠海冠宇电池股份有限公司 | Battery cell |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101000971A (en) * | 2006-12-27 | 2007-07-18 | 天津大学 | High safety, high power lithium ion power battery |
| CN101394008A (en) * | 2008-11-03 | 2009-03-25 | 广州天赐高新材料股份有限公司 | Lithium ion secondary battery using lithium iron phosphate as anode material with overall consideration of high and low temperature performance |
| CN103474708A (en) * | 2013-09-29 | 2013-12-25 | 天津力神电池股份有限公司 | Lithium ion battery comprising electrolyte solutions with improved safety and storage performance |
| CN106159330A (en) * | 2016-10-08 | 2016-11-23 | 东莞市凯欣电池材料有限公司 | A kind of PC base high-voltage electrolyte and a kind of lithium ion battery |
-
2016
- 2016-12-26 CN CN201611218759.2A patent/CN108242556B/en active Active
-
2017
- 2017-07-21 WO PCT/CN2017/093864 patent/WO2018120794A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101000971A (en) * | 2006-12-27 | 2007-07-18 | 天津大学 | High safety, high power lithium ion power battery |
| CN101394008A (en) * | 2008-11-03 | 2009-03-25 | 广州天赐高新材料股份有限公司 | Lithium ion secondary battery using lithium iron phosphate as anode material with overall consideration of high and low temperature performance |
| CN103474708A (en) * | 2013-09-29 | 2013-12-25 | 天津力神电池股份有限公司 | Lithium ion battery comprising electrolyte solutions with improved safety and storage performance |
| CN106159330A (en) * | 2016-10-08 | 2016-11-23 | 东莞市凯欣电池材料有限公司 | A kind of PC base high-voltage electrolyte and a kind of lithium ion battery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108242556A (en) | 2018-07-03 |
| WO2018120794A1 (en) | 2018-07-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108242556B (en) | Electrolyte solution and secondary battery | |
| WO2020248567A1 (en) | Secondary lithium-ion battery electrolyte for reducing battery resistance and secondary lithium-ion battery thereof | |
| CN109309226B (en) | Electrochemical energy storage device | |
| CN108123172B (en) | Electrolyte and secondary lithium battery | |
| CN110429335B (en) | Electrolyte solution, electrochemical device and electronic device comprising same | |
| CN108242557B (en) | Electrolyte solution and secondary battery | |
| CN107293782B (en) | Non-aqueous electrolyte and lithium ion battery | |
| WO2018120791A1 (en) | Electrolyte and secondary battery | |
| US20140356734A1 (en) | Electrolyte for lithium ion secondary battery and lithium ion secondary battery comprising the same | |
| CN109148951B (en) | Electrolyte and lithium ion battery | |
| CN110611121B (en) | Electrolyte and lithium ion battery containing same | |
| WO2018120793A1 (en) | Electrolyte and secondary battery | |
| CN109830749B (en) | Electrolyte and electrochemical device | |
| WO2018120787A1 (en) | Electrolyte and secondary battery | |
| CN109309246A (en) | Electrolyte and electrochemical energy storage device | |
| CN109390629B (en) | Electrolyte and battery | |
| WO2021179300A1 (en) | Electrochemical device and electronic device comprising same | |
| CN110808411B (en) | Electrolyte and lithium ion battery | |
| CN109309249B (en) | Electrolyte and electrochemical energy storage device | |
| CN109119599B (en) | Secondary battery and preparation method thereof | |
| US20220216515A1 (en) | Electrolyte and electrochemical apparatus | |
| CN110854432B (en) | Electrolyte solution, and electrochemical device and electronic device using same | |
| CN112103561A (en) | Electrolyte and electrochemical device | |
| CN111740162A (en) | Electrolyte solution, electrochemical device including the same, and electronic device | |
| WO2021128203A1 (en) | Electrolyte and electrochemical 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 |