CN111640985A - Non-aqueous electrolyte and high-voltage lithium ion battery containing same - Google Patents
Non-aqueous electrolyte and high-voltage lithium ion battery containing same Download PDFInfo
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- 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
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- 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
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- 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
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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- 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 invention provides a non-aqueous electrolyte and a high-voltage lithium ion battery containing the same. The non-aqueous electrolyte comprises a solvent, an additive and a conductive lithium salt; the solvent is a non-aqueous organic solvent, and the additives comprise a positive electrode protection additive, a negative electrode film forming additive and a low impedance additive; the positive electrode protection additive includes a nitrile compound including acrylonitrile, and at least two of the following nitrile compounds: succinonitrile, adiponitrile, 1, 2-bis (cyanoethoxy) ethane, 1,3, 6-hexanetrinitrile and glycerol trinitrile. The nitrile compound and the anode are complexed to form a similar protective layer, so that the anode structure is more stable, and the side reaction decomposition of the electrolyte is prevented by the metal ions dissolved out and catalyzed.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a non-aqueous electrolyte and a high-voltage lithium ion battery containing the same.
Background
In recent years, lithium ion batteries have been widely used in the fields of smart phones, tablet computers, smart wearing, electric tools, electric automobiles, and the like. With the acceleration of life rhythm and the development of electronic products, the demands of consumers on the charging environment and the energy density improvement of the lithium ion battery are more urgent, and correspondingly higher requirements on the use temperature range and the voltage of the lithium ion battery are provided; meanwhile, the lithium ion battery is required to have a long service life and high safety.
Therefore, there is a need to develop an electrolyte for a high-voltage soft-package lithium ion battery with long cycle life at high and low temperatures, and the lithium ion battery formed by the electrolyte has good storage and low-temperature charge and discharge properties. However, it is often difficult to simultaneously achieve high and low temperature performance with current electrolyte additives. Therefore, it is urgently required to develop a high-efficiency additive capable of broadening the use temperature of a high-voltage lithium ion battery and extending the cycle life of the battery.
Disclosure of Invention
The invention aims to solve the problem that the conventional electrolyte is difficult to simultaneously take high and low temperature performances into consideration and improve, and provides a non-aqueous electrolyte, a high-voltage lithium ion battery containing the non-aqueous electrolyte and a preparation method of the non-aqueous electrolyte. The non-aqueous electrolyte can simultaneously give consideration to and improve the high-low temperature performance of the high-voltage lithium ion battery.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a nonaqueous electrolyte comprising a solvent, an additive, and a conductive lithium salt; wherein the solvent is a non-aqueous organic solvent, and the additives comprise a positive electrode protection additive, a negative electrode film forming additive and a low impedance additive;
wherein the positive electrode protection additive comprises a nitrile compound comprising acrylonitrile and at least two of the following nitrile compounds: succinonitrile, adiponitrile, 1, 2-bis (cyanoethoxy) ethane, 1,3, 6-hexanetrinitrile and glycerol trinitrile;
the low impedance additive comprises lithium difluorophosphate;
the negative film forming additive comprises a carbonate compound.
In the invention, the nitrile compound is added into the electrolyte as the anode protection additive, and can be complexed with the anode to form a structure similar to a protection layer, so that the anode is more stable, and the side reaction decomposition of the electrolyte is prevented from being catalyzed by the dissolution of metal ions. The invention particularly introduces acrylonitrile, and the addition of the acrylonitrile can generate acrylonitrile free radicals after the negative electrode receives electrons, so as to initiate polymerization reaction to generate polyacrylonitrile to cover the surface of the electrode, thereby forming a tough SEI film, and realizing and improving the high and low temperature performance of the lithium ion battery.
Further, the electrolyte also comprises a high-temperature additive.
Further, the high temperature additive is selected from 1, 3-propane sultone.
Further, the carbonate compound is selected from vinylene carbonate and/or fluoroethylene carbonate.
Further, the dosage of the positive electrode protection additive accounts for 0.1-14 wt% of the total mass of the nonaqueous electrolyte. For example, 0.1 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%.
Further, the nitrile compounds include acrylonitrile, and at least three of the following nitrile compounds: succinonitrile, adiponitrile, 1, 2-bis (cyanoethoxy) ethane, 1,3, 6-hexanetrinitrile and glycerol trinitrile.
Further, the positive electrode protection additive comprises 0.1-3 wt% of acrylonitrile, 0.1-3 wt% of adiponitrile, 0.1-3 wt% of 1, 2-bis (cyanoethoxy) ethane and 0.1-5 wt% of 1,3, 6-hexanetrinitrile based on the total mass of the nonaqueous electrolyte.
Further, the positive electrode protection additive comprises 0.1-3 wt% of acrylonitrile, 0.1-3 wt% of adiponitrile, 0.1-2 wt% of succinonitrile and 0.1-5 wt% of 1,3, 6-hexanetrinitrile based on the total mass of the nonaqueous electrolyte.
Further, the positive electrode protection additive comprises 0.1-3 wt% of acrylonitrile, 0.1-3 wt% of adiponitrile, 0.1-2 wt% of succinonitrile and 0.1-3 wt% of glycerol trinitrile based on the total mass of the nonaqueous electrolyte.
Further, the positive electrode protection additive comprises 0.1-3 wt% of acrylonitrile, 0.1-3 wt% of adiponitrile, 0.1-5 wt% of 1,3, 6-hexanetrinitrile and 0.1-3 wt% of glycerol trinitrile based on the total mass of the nonaqueous electrolyte.
Further, the positive electrode protection additive comprises acrylonitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte, succinonitrile accounting for 0.1-2 wt%, 1,3, 6-hexanetricarbonitrile accounting for 0.1-5 wt% of the total mass of the nonaqueous electrolyte and 1, 2-bis (cyanoethoxy) ethane accounting for 0.1-3 wt%.
Further, the positive electrode protection additive comprises 0.1-3 wt% of acrylonitrile, 0.1-2 wt% of succinonitrile, 0.1-3 wt% of adiponitrile, 0.1-5 wt% of 1,3, 6-hexanetrinitrile and 0.1-3 wt% of 1, 2-bis (cyanoethoxy) ethane based on the total mass of the nonaqueous electrolyte.
Further, the positive electrode protection additive comprises acrylonitrile, succinonitrile, adiponitrile, 1,3, 6-hexanetrinitrile and 0.1-3 wt% of glycerol trinitrile, wherein the acrylonitrile, the succinonitrile, the adiponitrile, the 1, 3-hexanetrinitrile and the 1, 3-hexanetrinitrile account for 0.1-3 wt% of the total mass of the nonaqueous electrolyte.
Furthermore, the carbonate compound accounts for 5-20 wt% of the total mass of the non-aqueous electrolyte. For example, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, or 20 wt%.
Further, the high-temperature additive is used in an amount of 0.5 to 5 wt%, preferably 1 to 5 wt%, based on the total mass of the nonaqueous electrolytic solution. For example, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%.
Further, the lithium difluorophosphate is used in an amount of 0.01 to 2 wt%, preferably 0.1 to 2 wt%, based on the total mass of the nonaqueous electrolytic solution. For example, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 2 wt%.
In the present invention, the non-aqueous organic solvent refers to an organic solvent containing no water or water in ppm level (e.g., <0.1ppm), and for example, the organic solvent needs to be subjected to a water removal treatment such as a molecular sieve before use.
Further, the non-aqueous organic solvent is selected from a mixture in which at least one of cyclic carbonates and at least one of linear carbonates and linear carboxylates are mixed in an arbitrary ratio.
Preferably, the cyclic carbonate is selected from at least one of ethylene carbonate and propylene carbonate, the linear carbonate is selected from at least one of dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, and the linear carboxylate is selected from at least one of ethyl propionate, propyl propionate and propyl acetate.
Further, in the non-aqueous organic solvent, the volume fraction of the cyclic carbonate is 15 to 40 vol% and the volume fraction of the linear carbonate and/or the linear carboxylate is 60 to 85 vol% based on 100 vol% of the total volume.
Further, the conductive lithium salt is selected from at least one of lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide and lithium bis (trifluoromethanesulfonyl) imide.
Further, the concentration of the conductive lithium salt is 1 to 1.2mol/L, for example, 1mol/L, 1.1mol/L, 1.2 mol/L.
The invention also provides a preparation method of the non-aqueous electrolyte, which comprises the following steps:
and mixing a solvent, a conductive lithium salt and the additive to prepare the non-aqueous electrolyte.
Further, the mixing is not limited by the order of addition.
The invention also provides a lithium ion battery which comprises the non-aqueous electrolyte.
Further, the lithium ion battery also comprises a positive electrode, a negative electrode and a diaphragm.
Wherein the positive electrode comprises a positive electrode active material, a binder and a conductive agent, and the negative electrode comprises a negative electrode active material, a binder and a conductive agent.
Further, the mass ratio of the positive electrode active material, the binder, and the conductive agent is well known in the art.
Further, the mass ratio of the negative electrode active material, the binder, and the conductive agent is well known in the art.
Further, the positive electrode active material is selected from LiCoO2、LiNiO2、LiMn2O4、LiFePO4、LixNiyM1-yO2Wherein x is more than or equal to 0.9 and less than or equal to 1.2, and y is more than or equal to 0.5<1, M is selected from one or more of Co, Mn, Al, Mg, Ti, Zr, Fe, Cr, Mo, Cu and Ca.
Further, the negative active material is graphite or a graphite composite material containing 1-12 wt% of SiOx/C or Si/C, wherein 2> x > 0.
Further, the conductive agent is selected from conductive agents known in the art for preparing a positive electrode or a negative electrode, for example, from acetylene black, carbon nanotubes, and the like.
Further, the separator is a separator known in the art, such as a polyethylene separator, a polypropylene separator, and the like.
Further, the charge cut-off voltage of the lithium ion battery is 4.4V or more.
Furthermore, the lithium ion battery has a capacity retention ratio of 85-94% after being subjected to charge-discharge cycling at 45 ℃ and under a charge-discharge voltage interval of 3.0-4.4V and by using a 1C current for 400 weeks.
Furthermore, the capacity retention rate of the lithium ion battery after 6 hours of storage at 85 ℃ is 84-94%.
Further, the lithium ion battery is placed for 4 hours at the temperature of-20 ℃ and then is discharged to 3V at the rate of 0.4C, and the low-temperature discharge capacity retention rate is 35-45%.
The invention also provides a preparation method of the lithium ion battery, which comprises the following steps:
(1) preparing a positive plate and a negative plate, wherein the positive plate contains a positive active substance, and the negative plate contains a negative active substance;
(2) mixing a solvent, a conductive lithium salt and the additive to prepare an electrolyte;
(3) winding the positive plate, the diaphragm and the negative plate to obtain a naked battery cell without liquid injection; and (3) placing the bare cell in an outer packaging foil, injecting the electrolyte in the step (2) into the dried bare cell, and preparing to obtain the lithium ion battery.
Exemplarily, the method specifically comprises the following steps:
1) preparing a positive plate:
mixing ternary material (LiNi) of positive electrode active material0.5Co0.3Mn0.2O2) Mixing polyvinylidene fluoride (PVDF) serving as a binder and acetylene black serving as a conductive agent according to a weight ratio of 96.5:2:1.5, adding N-methylpyrrolidone (NMP), and stirring under the action of a vacuum stirrer until a mixed system becomes uniform and flowable anode slurry; uniformly coating the positive electrode slurry on an aluminum foil with the thickness of 9-12 mu m; drying the coated aluminum foil in an oven at the temperature of 100-130 ℃ for 4-10h, and then rolling and slitting to obtain a required positive plate;
2) preparing a negative plate:
preparing a graphite negative electrode material with the mass ratio of 95.9 wt%, a single-walled carbon nanotube (SWCNT) conductive agent with the mass ratio of 0.1 wt%, a conductive carbon black (SP) conductive agent with the mass ratio of 1 wt%, a sodium carboxymethylcellulose (CMC) binder with the mass ratio of 1 wt% and a Styrene Butadiene Rubber (SBR) binder with the mass ratio of 2% into slurry by a wet process, coating the slurry on the surface of a negative current collector copper foil, drying (the temperature is 85 ℃, the time is 5h), rolling and die cutting to obtain a graphite negative electrode sheet;
3) preparing an electrolyte:
uniformly mixing ethylene carbonate, propylene carbonate, diethyl carbonate and n-propyl propionate according to the mass ratio of 20:10:15:55 in a glove box filled with argon and qualified in water oxygen content, then quickly adding 1mol/L of fully dried lithium hexafluorophosphate and an additive, and uniformly stirring to prepare an electrolyte;
4) preparing a diaphragm:
selecting a polyethylene diaphragm with the thickness of 7-9 mu m;
5) preparation of lithium ion battery
Winding the prepared positive plate, the diaphragm and the prepared negative plate to obtain a naked battery cell without liquid injection; placing the bare cell in an outer packaging foil, injecting the prepared electrolyte into the dried bare cell, and performing vacuum packaging, standing, formation, shaping, sorting and other processes to obtain the required lithium ion battery.
Has the advantages that:
the invention provides a high-voltage lithium ion battery containing a nonaqueous electrolyte and a preparation method thereof. The lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm and electrolyte, wherein the positive electrode comprises a positive active material, a binder and a conductive agent, the negative electrode comprises a negative active material, a binder and a conductive agent, the electrolyte comprises a solvent, an additive and a conductive lithium salt, and the additive comprises a positive protective additive, namely a nitrile compound, a negative film forming additive, namely a carbonate compound, and a low-impedance additive, namely lithium difluorophosphate. The nitrile compound and the anode are complexed to form a structure similar to a protective layer, so that the anode structure is more stable, and the side reaction decomposition of the electrolyte is prevented from being catalyzed by the dissolution of metal ions. Meanwhile, acrylonitrile in the positive electrode protection additive can generate acrylonitrile free radicals after the negative electrode receives electrons, the acrylonitrile is initiated to generate polyacrylonitrile to cover the surface of the electrode, a firm but slightly high-impedance composite SEI film can be formed on the surface of the negative electrode together with negative electrode film forming additives (fluoroethylene carbonate and vinylene carbonate), the protection is enhanced, the high-temperature cycle performance is guaranteed, the negative electrode impedance is further reduced through the low-impedance additive (lithium difluorophosphate), an inorganic frame structure can be provided for the composite SEI film formed by the positive electrode protection additive, lithium ions can be transported efficiently, and therefore the lithium ion battery is guaranteed to have excellent high-temperature performance and low-temperature performance.
Detailed Description
The present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.
Comparative examples 1 to 7 and examples 1 to 12
The lithium ion batteries of comparative examples 1 to 7 and examples 1 to 12 were each prepared according to the following preparation method, except for the selection and addition of additives, and the specific differences are shown in table 1.
(1) Preparation of positive plate
LiNi as positive electrode active material0.5Co0.3Mn0.2O2Mixing polyvinylidene fluoride (PVDF) serving as a binder and acetylene black serving as a conductive agent according to a weight ratio of 96.5:2:1.5, adding N-methylpyrrolidone (NMP), and stirring under the action of a vacuum stirrer until a mixed system becomes uniform and flowable anode slurry; uniformly coating the positive electrode slurry on an aluminum foil with the thickness of 9-12 mu m; baking the coated aluminum foil in 5 sections of baking ovens with different temperature gradients, drying the aluminum foil in a baking oven at 120 ℃ for 8 hours, and rolling and cutting to obtain the required positive plate.
(2) Preparation of negative plate
Preparing a graphite negative electrode material with the mass ratio of 95.9 wt%, a single-walled carbon nanotube (SWCNT) conductive agent with the mass ratio of 0.1 wt%, a conductive carbon black (SP) conductive agent with the mass ratio of 1 wt%, a sodium carboxymethylcellulose (CMC) binder with the mass ratio of 1 wt% and a Styrene Butadiene Rubber (SBR) binder with the mass ratio of 2 wt% into slurry by a wet process, coating the slurry on the surface of a negative current collector copper foil, drying (the temperature is 85 ℃, the time is 5 hours), rolling and die cutting to obtain the graphite negative electrode.
(3) Preparation of electrolyte
Uniformly mixing ethylene carbonate, propylene carbonate, diethyl carbonate and n-propyl propionate according to the mass ratio of 20:10:15:55 in a glove box filled with argon and qualified in water oxygen content (the solvent needs to be normalized), and quickly adding 1mol/L of fully dried lithium hexafluorophosphate (LiPF)6) And additives (specific amounts and selections are shown in table 1) to obtain an electrolyte.
(4) Preparation of the separator
The polyethylene diaphragm with the thickness of 7-9 μm is selected.
(5) Preparation of lithium ion battery
Winding the prepared positive plate, the diaphragm and the prepared negative plate to obtain a naked battery cell without liquid injection; placing the bare cell in an outer packaging foil, injecting the prepared electrolyte into the dried bare cell, and performing vacuum packaging, standing, formation, shaping, sorting and other processes to obtain the required lithium ion battery.
TABLE 1 composition of additives in comparative examples 1 to 7 and examples 1 to 12 (unit: mass fraction wt%)
The lithium ion batteries in the examples and comparative examples were tested for high temperature cycle, high temperature storage, and low temperature discharge performance under the following specific test conditions:
high-temperature cycle test: the batteries obtained in the examples and comparative examples were left at 45 ℃ for charge-discharge cycles using a current of 1C in a charge-discharge voltage interval of 3.0 to 4.4V, and the initial capacity Q and the initial thickness T were recorded, and the capacity Q was selected for cycles up to 400 weeks1And thickness is denoted as T0The capacity retention of the battery at high temperature cycle for 400 weeks was calculated by the following formula, and the results are reported in table 2.
Capacity retention (%) ═ Q1/Q×100；
Thickness change rate (%) - (T-T)0)/T×100；
High temperature storage at 85 ℃ for 6 hours experiment: examples will be given inThe cell obtained in the comparative example was subjected to a charge-discharge cycle test at room temperature for 3 times at a charge-discharge rate of 1C, and then the cell was charged to a full charge at a rate of 1C, and the maximum discharge capacity Q of the previous 3 1C cycles was recorded2. The fully charged cells were stored at 85 ℃ for 6 hours and the 1C discharge capacity Q of the cells after 6 hours was recorded3And calculating to obtain the capacity retention rate of the battery after storage, and recording the gas production condition of the battery, wherein the recording result is shown in table 2.
The calculation formula used therein is as follows: capacity retention (%) ═ Q3/Q2×100％。
And (3) low-temperature discharge test: the cells obtained in examples and comparative examples were subjected to 3 charge-discharge cycles at room temperature at a rate of 1C, and then charged to a full charge state at a rate of 1C, and a 1C capacity Q was recorded4. The battery in full charge state is placed at-20 ℃ for 4h, then discharged to 3V at 0.4C rate, and the discharge capacity Q is recorded5The low-temperature discharge capacity retention rate can be obtained by calculation, the low-temperature discharge capacity retention rate of the battery is calculated by the following formula, and the recorded results are shown in table 2.
Capacity retention (%) ═ Q5/Q4×100。
As can be seen from the results of table 2: it can be seen from comparison of comparative examples 1 to 3 that the addition and optimization of nitrile compounds can significantly improve the high-temperature cycle performance and high-temperature storage electrical performance of batteries, but the low-temperature discharge is poor. Further, by comparing comparative examples 2 and 5, it can be seen that the low-temperature performance of the battery can be improved by adding lithium difluorophosphate, and meanwhile, by comparing comparative examples 2 and 4, the high-temperature cycle performance of the battery can be effectively improved by adding negative electrode film-forming fluoroethylene carbonate. Further, as can be seen from comparison of examples 1 to 9 with comparative examples 1 to 7, the optimized combination of the additives nitrile compound, fluoroethylene carbonate, 1, 3-propane sultone, vinylene carbonate and lithium difluorophosphate can significantly improve the high-temperature cycle and high-temperature storage performance of the high-voltage lithium ion battery, and simultaneously have good low-temperature discharge performance. Further, as can be seen from comparative examples 1, 10 to 12 and comparative example 6 or from comparative example 2 and comparative example 7, by selecting a combination of three or more nitrile compounds as additives, the resulting battery achieves better high-temperature performance and is more excellent in safety performance under high-temperature conditions. In particular, when acrylonitrile is selected as the positive electrode protective additive, the battery achieves better high-temperature and low-temperature properties.
TABLE 2 results of experimental tests of comparative examples 1 to 7 and examples 1 to 12
In summary, the non-aqueous electrolyte for the high-voltage lithium ion battery provided by the invention contains an optimized combination of various additives such as a positive electrode protection additive nitrile compound, a negative electrode film-forming additive carbonate compound, a high-temperature additive 1, 3-propane sultone, a low-impedance additive lithium difluorophosphate and the like, and the additives have a synergistic effect, so that the high-voltage lithium ion battery has excellent high-temperature cycle and high-temperature storage electrical properties, and simultaneously forms an excellent interface to reduce impedance, and can also have low-temperature discharge performance.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A nonaqueous electrolytic solution, wherein the nonaqueous electrolytic solution comprises a solvent, an additive and a conductive lithium salt; the solvent is a non-aqueous organic solvent, and the additives comprise a positive electrode protection additive, a negative electrode film forming additive and a low impedance additive;
wherein the positive electrode protection additive comprises a nitrile compound comprising acrylonitrile and at least two of the following nitrile compounds: succinonitrile, adiponitrile, 1, 2-bis (cyanoethoxy) ethane, 1,3, 6-hexanetrinitrile and glycerol trinitrile;
the low impedance additive comprises lithium difluorophosphate;
the negative film forming additive comprises a carbonate compound.
2. The nonaqueous electrolytic solution of claim 1, wherein the additive further comprises a high temperature additive.
3. The nonaqueous electrolytic solution of claim 2, wherein the high-temperature additive is selected from 1, 3-propane sultone.
4. The nonaqueous electrolytic solution of claims 1 to 3, wherein the positive electrode protection additive is 0.1 to 3 wt% of acrylonitrile, 0.1 to 3 wt% of adiponitrile, 0.1 to 3 wt% of 1, 2-bis (cyanoethoxy) ethane, and 0.1 to 5 wt% of 1,3, 6-hexanetrinitrile, based on the total mass of the nonaqueous electrolytic solution; alternatively, the first and second electrodes may be,
the positive electrode protection additive comprises acrylonitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte, adiponitrile accounting for 0.1-3 wt%, succinonitrile accounting for 0.1-2 wt% and 1,3, 6-hexanetrinitrile accounting for 0.1-5 wt% of the total mass of the nonaqueous electrolyte; alternatively, the first and second electrodes may be,
the positive electrode protective additive comprises acrylonitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte, adiponitrile accounting for 0.1-3 wt%, succinonitrile accounting for 0.1-2 wt% and glycerol trinitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte; alternatively, the first and second electrodes may be,
the positive electrode protective additive comprises acrylonitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte, adiponitrile accounting for 0.1-3 wt%, 1,3, 6-hexanetricarbonitrile accounting for 0.1-5 wt% of the total mass of the nonaqueous electrolyte and glycerol trinitrile accounting for 0.1-3 wt%; alternatively, the first and second electrodes may be,
the positive electrode protection additive comprises acrylonitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte, succinonitrile accounting for 0.1-2 wt%, 1,3, 6-hexanetricarbonitrile accounting for 0.1-5 wt% of the total mass of the nonaqueous electrolyte and 1, 2-bis (cyanoethoxy) ethane accounting for 0.1-3 wt%; alternatively, the first and second electrodes may be,
the positive electrode protection additive comprises acrylonitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte, succinonitrile accounting for 0.1-2 wt%, adiponitrile accounting for 0.1-3 wt%, 1,3, 6-hexanetrinitrile accounting for 0.1-5 wt% and 1, 2-di (cyanoethoxy) ethane accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte; alternatively, the first and second electrodes may be,
the positive electrode protection additive comprises acrylonitrile accounting for 0.1-3 wt% of the total mass of the nonaqueous electrolyte, succinonitrile accounting for 0.1-2 wt%, adiponitrile accounting for 0.1-3 wt%, 1,3, 6-hexanetricarbonitrile accounting for 0.1-5 wt% of the total mass of the nonaqueous electrolyte and glycerol trinitrile accounting for 0.1-3 wt%.
5. The nonaqueous electrolytic solution of any one of claims 1 to 4, wherein the carbonate-based compound is selected from vinylene carbonate and/or fluoroethylene carbonate; the amount of the carbonate compound is 5-20 wt% of the total mass of the non-aqueous electrolyte.
6. The nonaqueous electrolytic solution of any one of claims 2 to 5, wherein the amount of the high-temperature additive is 0.5 to 5 wt% based on the total mass of the nonaqueous electrolytic solution.
7. The nonaqueous electrolytic solution of any one of claims 1 to 6, wherein the amount of the lithium difluorophosphate is 0.01 to 2 wt% based on the total mass of the nonaqueous electrolytic solution.
8. The nonaqueous electrolytic solution of any one of claims 1 to 7, wherein the nonaqueous organic solvent is selected from a mixture in which at least one of cyclic carbonates and at least one of linear carbonates and linear carboxylates are mixed in an arbitrary ratio.
9. A lithium ion battery comprising the nonaqueous electrolytic solution of any one of claims 1 to 8.
10. The lithium ion battery according to claim 9, wherein the lithium ion battery comprises at least one of the following (1) to (3):
(1) the charge cut-off voltage of the lithium ion battery is more than 4.4V;
(2) under the condition of 45 ℃, the lithium ion battery uses 1C current to perform charge-discharge circulation to 400 weeks under the charge-discharge voltage interval of 3.0-4.4V, and the capacity retention ratio is 85-94%;
(3) the capacity retention rate of the lithium ion battery after 6 hours of storage at 85 ℃ is 84-94%.
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| CN112751084A (en) * | 2020-12-30 | 2021-05-04 | 珠海冠宇电池股份有限公司 | Non-aqueous electrolyte for lithium ion battery and lithium ion battery comprising same |
| CN112751085A (en) * | 2020-12-30 | 2021-05-04 | 珠海冠宇电池股份有限公司 | Non-aqueous electrolyte for lithium ion battery and lithium ion battery comprising same |
| CN113013489A (en) * | 2021-02-25 | 2021-06-22 | 珠海冠宇电池股份有限公司 | Electrolyte and lithium ion battery comprising same |
| CN113422105A (en) * | 2021-06-29 | 2021-09-21 | 珠海冠宇电池股份有限公司 | Lithium ion battery and electronic device |
| CN113839093A (en) * | 2021-09-16 | 2021-12-24 | 湖州昆仑亿恩科电池材料有限公司 | Non-aqueous electrolyte of lithium ion battery and application thereof |
| CN114024033A (en) * | 2020-12-30 | 2022-02-08 | 珠海冠宇电池股份有限公司 | Non-aqueous electrolyte for lithium ion battery and lithium ion battery comprising same |
| JP2023503203A (en) * | 2020-10-15 | 2023-01-27 | 寧徳新能源科技有限公司 | electrochemical and electronic devices |
| WO2023182649A1 (en) * | 2022-03-21 | 2023-09-28 | 주식회사 엘지에너지솔루션 | Lithium secondary battery having suppressed metal elution |
| WO2024021962A1 (en) * | 2022-07-28 | 2024-02-01 | 张家港市国泰华荣化工新材料有限公司 | Non-aqueous electrolyte solution and lithium ion battery |
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