CN109873198A - Electrolyte and battery - Google Patents
Electrolyte and battery Download PDFInfo
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- CN109873198A CN109873198A CN201711271121.XA CN201711271121A CN109873198A CN 109873198 A CN109873198 A CN 109873198A CN 201711271121 A CN201711271121 A CN 201711271121A CN 109873198 A CN109873198 A CN 109873198A
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- 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
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E60/10—Energy storage using batteries
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Abstract
This application provides electrolyte and battery, the electrolyte includes fluorochemical and additive.Additive can form stable solid electrolyte interface film (SEI film) in battery forming process middle-jiao yang, function of the spleen and stomach pole surface, decomposition of other components in anode surface in inhibition electrolyte, and fluorochemical has excellent stability and extremely low surface tension, one layer of liquid film can be formed in electrode surface, so that electrolyte improves the cycle performance of battery in the decomposition of electrode surface during alleviating circulating battery；The two collaboration, mating reaction can further improve the cycle performance of battery, contain above-mentioned fluorochemical simultaneously in electrolyte and the cycle performance of battery of additive is good, the service life is long.
Description
Technical field
This application involves field of batteries, specifically, being related to electrolyte and battery.
Background technique
Currently, lithium ion battery applications field is extensive, with advantages such as high-energy density, memory-less effects, answered
For fields such as electric car, consumption electronic product, energy storage devices, and it is increasingly becoming the mainstream battery in above-mentioned field.But it is current
The common cycle performance of lithium ion battery of people is poor, and generally after using 2 years, cycle performance is decayed clearly, seriously affects
The consumption experience of consumer, and then lithium ion battery large-scale promotion in the market is influenced, thus, current battery needs
It improves.
Summary of the invention
The application is intended to solve at least some of the technical problems in related technologies.For this purpose, the application
One be designed to provide it is a kind of can be effectively improved the cycle performance of battery or the electrolyte of service life and containing its
Battery.
In the one aspect of the application, this application provides a kind of electrolyte.According to an embodiment of the present application, the electrolysis
Liquid includes fluorochemical and additive.Inventors have found that additive can form stabilization in battery forming process middle-jiao yang, function of the spleen and stomach pole surface
Solid electrolyte interface film (SEI film), inhibit electrolyte in other components anode surface decomposition, and fluorochemical have
There are excellent stability and extremely low surface tension, it, can be in electrode when that will be injected in battery containing the electrolyte of fluorochemical
Surface forms one layer of liquid film, avoids electrolyte from contacting with the direct of electrode surface, to alleviate electrolyte during circulating battery
It is consumed in the reaction of electrode surface, improves the cycle performance of battery；Moreover, inventor also found, using containing simultaneously containing above-mentioned
The cycle performance ratio that the battery of the electrolyte of fluorine compounds and electrolysis additive is shown only use above-mentioned fluorochemical or
Only using above-mentioned electrolysis additive will be more excellent, and the synergistic effect of the two, which further enhances, is formed by SEI film
Thermal stability slows down in long-term cyclic process and causes electrolyte persistently to consume due to last decomposition and the formation of SEI film, and two
Person can cooperate with, mating reaction, and cycle performance of battery significantly improves, and the service life is obviously prolonged, and service performance is very good.
In addition, can also have the following additional technical features: according to the electrolyte of above-described embodiment of the application
According to an embodiment of the present application, the fluorochemical is one of perfluoropolyether and perfluoro alkane or a variety of.
Perfluoropolyether and perfluoro alkane form liquid film in electrode surface by its lower surface tension, by one of the two or a variety of
It is mixed and is injected in battery with electrolyte, electrolyte can be alleviated during circulating battery in the decomposition of electrode surface, from
And improve the cycle performance of battery.
According to an embodiment of the present application, the additive is selected from vinylene carbonate, fluoro ethylene carbonate, dioxalic acid
One of lithium borate and difluorine oxalic acid boracic acid lithium are a variety of.As a result, stabilization can be formed in battery forming process middle-jiao yang, function of the spleen and stomach pole surface
Solid electrolyte interface film (SEI film), inhibit electrolyte in other components in the decomposition of anode surface, be effectively improved battery
Cycle performance.
According to an embodiment of the present application, the fluorochemical is in a liquid state under room temperature (25 DEG C), and boiling point is not less than 80
Degree Celsius.Fluorochemical boiling point is higher as a result, and electrochemical properties are stablized, and use temperature range is wider, low temperature resistant and high temperatures
Preferably it can effectively can inhibit the ingredient in electrolyte to decompose in electrode surface, battery can be effectively improved when applied to battery
Cycle performance, extend the service life of battery.
According to an embodiment of the present application, the gross mass based on the electrolyte, the mass fraction of the fluorochemical are
0.01%~2%.The mass fraction of fluorochemical can be obviously improved the cycle performance of battery within the above range, and guarantee
The first charge-discharge of battery efficiency with higher.
According to an embodiment of the present application, the perfluoropolyether is selected from one of the following or a variety of:
Wherein, m and n respectively may be the same or different, and indicate to be greater than 1 integer.Perfluor containing 1~formula of formula, 4 structure is poly-
Ether surface tension is low, and one or more by the perfluoropolyether of above structure inject in battery together with electrolyte, follows in battery
Protection liquid film can be formed in electrode surface during ring, protect electrolyte not to be decomposed, so as to improve poly- containing above-mentioned perfluor
The cycle performance and service life of the battery of ether.
According to an embodiment of the present application, the molecular weight of the perfluoropolyether is greater than 400.The perfluoropolyether can as a result,
Protection liquid film effectively is formed in electrode surface, and then contains the electrolyte long service life of above-mentioned perfluoropolyether, contains the electrolysis
The cycle performance of battery of liquid is preferable.
According to an embodiment of the present application, the chemical formula of the perfluoro alkane are as follows: CxF2x+2(formula 5), wherein x, which is selected from, is greater than 5
Integer.The perfluoro alkane surface tension of above structure is low, can electrode surface formed protection liquid film, protect electrolyte not by
It decomposes, to improve the service life of the electrolyte containing above-mentioned perfluoro alkane, and then improves the battery containing the electrolyte and follow
Ring performance.
According to an embodiment of the present application, the gross mass based on the electrolyte, the mass fraction of the vinylene carbonate
It is 0.1%~4%, the mass fraction of the fluoro ethylene carbonate is 0.5%~20%, the quality of the dioxalic acid lithium borate
Score is 0.1%~4%, and the mass fraction of the difluorine oxalic acid boracic acid lithium is 0.1%~4%.Electrolyte in battery as a result,
Manufacturing cost is low within the above range for additive mass fraction, and can be sufficiently formed SEI film in the anode surface of battery, hence it is evident that changes
The cycle performance of kind battery, and the storage gas generation property of battery will not be deteriorated, so that the service life of battery extends, service performance
Preferably.
According to an embodiment of the present application, above-mentioned electrolyte further includes lithium salts, and the lithium salts is selected from inorganic lithium salt and organolithium
One of salt is a variety of；Preferably, the lithium salts is selected from lithium hexafluoro phosphate (LiPF6), difluorophosphate (LiPO2F2), tetrafluoro
Lithium borate (LiBF4), hexafluoroarsenate lithium, lithium perchlorate, double fluorine sulfimide lithiums (LiFSI), double trifluoromethanesulfonimide lithiums
One of (LiTFSI) or it is a variety of；It is further preferred that the lithium salts is lithium hexafluoro phosphate (LiPF6).Above-mentioned lithium salts electrification
Have good stability, and is soluble in organic solvent, is easy to dissociate, and guarantees electrolyte lithium ion conductivity with higher, decomposes and produces
Object has fewer environmental impacts, and has environmental-friendly performance, and is easy to purify and prepare, and price is lower.
According to an embodiment of the present application, above-mentioned electrolyte further includes organic solvent, and the organic solvent is selected from ethylene carbonate
Ester, propene carbonate, butylene, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, carbonic acid first third
One in ester, ethyl propyl carbonic acid ester, 1,4- butyrolactone, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate and ethyl butyrate
Kind is a variety of.Above-mentioned organic solvent viscosity and dielectric constant are moderate, and good thermal stability, use temperature range is wide, chemistry and electricity
Chemical property is good, and safety and the compatibility height with environment, price are low.
In the another aspect of the application, this application provides a kind of batteries.According to an embodiment of the present application, the battery pack
Include mentioned-above electrolyte.The cycle performance of battery is remarkably reinforced, and service life significantly extends, and can greatly improve user's body
It tests.
Specific embodiment
Embodiments herein is described below in detail.The embodiments described below is exemplary, and is only used for explaining this Shen
Please, it should not be understood as the limitation to the application.Particular technique or condition are not specified in embodiment, according to text in the art
Described technology or conditions are offered, or are carried out according to product description.Reagents or instruments used without specified manufacturer,
For can be with conventional products that are commercially available.
The application is following discovery based on inventor and understanding and completes:
It is by perfluoropolyether and perfluoro alkane to improve the cycle performance of battery its method used in existing battery
At least one of inject lithium ion battery together with electrolyte, perfluoropolyether or perfluoro alkane rely on its lower surface tension
Coating is formed in electrode surface, alleviates electrolyte in the decomposition of electrode surface, so as to improve the cycle performance of lithium ion battery.But
It is that the liquid film formed by liquid perfluoropolyether and perfluoro alkane molecule is limited to the protecting effect of electrode, it can only be to a certain degree
The upper cycle performance for improving lithium ion battery.Which limits lithium ion batteries to apply in the market, to not be able to satisfy city
The demand of field.Inventor has found that will have fluorochemical and electrolysis additive compared with low-surface-energy to add simultaneously
Enter electrolyte, can cooperate with, mating reaction, forms protecting effect more preferably protective film in electrode surface, and then be obviously improved electricity
The cycle performance and service life in pond, and then meet higher and higher market demands, improve user experience.
In view of this, this application provides a kind of electrolyte in the one aspect of the application.According to the implementation of the application
Example, the electrolysis include fluorochemical and additive.Inventors have found that additive can be in battery forming process in anode table
Face is formed stable solid electrolyte interface film (SEI film), other components in electrolyte is inhibited to improve in the decomposition of anode surface
The cycle performance of battery, and fluorochemical have excellent stability with extremely low surface tension, and lower than electrolyte
It together and in the dry core of electrolyte injection battery, can be formed one layer of liquid film in electrode surface, to alleviate electricity by surface tension
Electrolyte improves the cycle performance of battery in the decomposition of electrode surface in the cyclic process of pond；Contain above-mentioned fluorochemical simultaneously
With the electrolyte of additive, the two can be cooperateed with, mating reaction, so that the cycle performance of battery containing the electrolyte significantly changes
Kind, the service life is obviously prolonged, and service performance is very good, and performance is substantially better than only containing in fluorochemical and electrolysis additive
A kind of battery.
According to an embodiment of the present application, in order to improve the cycle performance of battery, the property of fluorochemical is not limited especially
System, as long as can satisfy low-surface-energy and the needs for protecting electrolyte not to be decomposed, those skilled in the art can be with flexible choice.
In some embodiments of the present application, the fluorochemical is in a liquid state under room temperature (25 DEG C), and boiling point is Celsius not less than 80
Degree.Fluorochemical boiling point is higher as a result, and property is stablized, and use temperature range is wider, and low temperature resistant and high-temperature behavior is preferable, can
Effectively to inhibit the ingredient in electrolyte to decompose in electrode, it can be effectively improved the cycle performance of battery when applied to battery, prolong
The service life of long battery.
According to an embodiment of the present application, the type of fluoride is not particularly limited, as long as can satisfy with lower
Surface tension, those skilled in the art can according to need flexible choice.It is described containing fluorination in some embodiments of the present application
It closes object and is selected from one of perfluoropolyether and perfluoro alkane or a variety of.Perfluoropolyether and perfluoro alkane are lower by its as a result,
Surface tension forms liquid film in electrode surface, and at least one of the two is mixed with electrolyte and is injected in battery, in electricity
Electrolyte can be alleviated in the cyclic process of pond in the decomposition of electrode surface, so as to improve the cycle performance of battery.
According to an embodiment of the present application, the structure of perfluoropolyether is not particularly limited, as long as it is low to can satisfy surface tension
Needs, those skilled in the art can be with flexible choice.In some embodiments of the present application, the perfluoropolyether is selected from following
One of or it is a variety of:
Wherein, m and n respectively may be the same or different, and indicate to be greater than 1 integer.As a result, containing the complete of 1~formula of formula, 4 structure
Perfluoroalkyl polyether surface tension is low, and the perfluoropolyether containing above structure is injected in battery together with electrolyte, in circulating battery mistake
Protection liquid film can be formed in electrode surface in journey, protect electrolyte not to be decomposed, so as to improve above-mentioned perfluoropolyether is contained
The cycle performance and service life of battery.
According to an embodiment of the present application, the molecular size range of perfluoropolyether is not particularly limited, as long as meeting needs, ability
Field technique personnel can be with flexible choice.In some embodiments of the present application, the molecular weight of the perfluoropolyether is greater than 400.By
This, the chemical property of perfluoropolyether is stablized, and perfluoropolyether can be effectively formed protective film layer in electrode surface, and then containing upper
It states the cycle performance of battery of perfluoropolyether well and long service life, the cycle performance of battery containing the electrolyte is preferable.
According to an embodiment of the present application, the structure of perfluoro alkane is not particularly limited, as long as meeting needs, art technology
Personnel can be with flexible choice.In some embodiments of the present application, the chemical formula of the perfluoro alkane are as follows: CxF2x+2, wherein x choosing
From the integer for being greater than 5, chemical structure can be branch or linear chain structure.In preferable situation, the perfluoro alkane is selected from room temperature
It is in liquid under (25 DEG C), such as perfluor dodecane (C12F26).The perfluoro alkane surface tension containing above structure is low as a result, can
Protective film layer is formed in electrode surface, electrolyte is protected not to be decomposed, so that the electrolyte containing above-mentioned perfluoro alkane be injected
The cycle performance of battery can be improved in battery, and extend the service life of battery, service performance is preferable.
According to an embodiment of the present application, in order to alleviate electrolyte in the decomposition of electrode surface, based on the total of the electrolyte
Quality, the mass fraction of the fluorochemical are 0.01%~2%.The mass fraction of fluorochemical within the above range can
It is enough to be sufficiently formed protection liquid film in electrode surface, the decomposition of electrolyte is effectively relieved, the battery containing above-mentioned fluorochemical
Cycle performance is obviously improved, and guarantees the first charge-discharge efficiency with higher of battery.When the quality of fluorochemical
It is insufficient in the protection liquid film that electrode surface is formed when percentage composition is lower than 0.01%, to cycle performance of lithium ion battery
Improve it is unobvious, when the mass percentage of fluorochemical be higher than 2% when, can reduce lithium ion battery first charge-discharge effect
Rate.
According to an embodiment of the present application, it in order to further improve the cycle performance of battery, is added in above-mentioned electrolyte suitable
The additive of amount, additive are selected from vinylene carbonate, fluoro ethylene carbonate, dioxalic acid lithium borate and difluorine oxalic acid boracic acid lithium
One of or it is a variety of.Electrolysis additive is at low cost as a result, and can form SEI in battery forming process middle-jiao yang, function of the spleen and stomach pole surface
Film, inhibit electrolyte in other components anode surface decomposition, additive and fluorochemical synergistic effect under, Ke Yiming
The aobvious cycle performance for improving battery, so that the service life of battery extends, service performance is preferable.
In some embodiments of the present application, based on the gross mass of the electrolyte, the vinylene carbonate (VC)
Mass fraction is 0.1%~4%, and the mass fraction of the electrolysis additive vinylene carbonate in battery is in above-mentioned model as a result,
It is low to enclose interior manufacturing cost, and SEI film can be sufficiently formed in battery forming process middle-jiao yang, function of the spleen and stomach pole surface, inhibits other groups in electrolyte
Decomposition of the part in anode surface, hence it is evident that improve the cycle performance of battery, and the storage gas generation property of battery will not be deteriorated, so that electric
The service life in pond extends, and service performance is preferable.When the mass percentage of vinylene carbonate is lower than 0.1%, in electricity
Pond formation process middle-jiao yang, function of the spleen and stomach pole surface not sufficiently forms SEI film, so that the improvement to cycle performance of battery is unobvious, when carbonic acid Asia
When the mass percentage of vinyl acetate is higher than 4%, the storage gas generation property of lithium ion battery can be deteriorated, influence the usability of battery
Can, increase manufacturing cost.
In some embodiments of the present application, based on the gross mass of the electrolyte, the fluoro ethylene carbonate (FEC)
Mass fraction be 0.5%~20%.The mass fraction of the electrolysis additive fluoro ethylene carbonate in battery is upper as a result,
It is low to state manufacturing cost in range, and SEI film can be sufficiently formed in battery forming process middle-jiao yang, function of the spleen and stomach pole surface, hence it is evident that improves battery
Cycle performance, and the storage gas generation property of battery will not be deteriorated, so that the service life of battery extends, service performance is preferable.When
The mass percentage of fluoro ethylene carbonate be lower than 0.5% when, battery forming process middle-jiao yang, function of the spleen and stomach pole surface cannot abundant shape
It is unobvious to the improvement of cycle performance of lithium ion battery at SEI film, when the mass percentage of fluoro ethylene carbonate is higher than
When 20%, to the cycle performance of lithium ion battery without further improvement result, while the storage that can deteriorate lithium ion battery produces gas
Performance increases manufacturing cost.
In some embodiments of the present application, based on the gross mass of the electrolyte, the dioxalic acid lithium borate (LiBOB)
Mass fraction be 0.1%~4%.The mass fraction of the electrolysis additive dioxalic acid lithium borate in battery is above-mentioned as a result,
Manufacturing cost is low in range, and can be sufficiently formed SEI film in battery forming process middle-jiao yang, function of the spleen and stomach pole surface, hence it is evident that improves following for battery
Ring performance, and the storage gas generation property of battery will not be deteriorated, so that the service life of battery extends, service performance is preferable.When two
When the mass percentage of Lithium bis (oxalate) borate is lower than 0.1%, SEI is not sufficiently formed in battery forming process middle-jiao yang, function of the spleen and stomach pole surface
Film, it is unobvious to the improvement of cycle performance of lithium ion battery, when the mass percentage of dioxalic acid lithium borate is higher than 4%, meeting
Deteriorate the storage gas generation property of lithium ion battery, and increases manufacturing cost.
In some embodiments of the present application, based on the gross mass of the electrolyte, the difluorine oxalic acid boracic acid lithium
(LiODFB) mass fraction is 0.1%~4%.The quality of electrolysis additive difluorine oxalic acid boracic acid lithium in battery as a result,
Manufacturing cost is low within the above range for score, and can be sufficiently formed SEI film in battery forming process middle-jiao yang, function of the spleen and stomach pole surface, hence it is evident that changes
The cycle performance of kind battery, and the storage gas generation property of battery will not be deteriorated, so that the service life of battery extends, service performance
Preferably.When the mass percentage of difluorine oxalic acid boracic acid lithium be lower than 0.1% when, battery forming process middle-jiao yang, function of the spleen and stomach pole surface cannot
It is sufficiently formed SEI film, it is unobvious to the improvement of cycle performance of lithium ion battery, when the mass percentage of difluorine oxalic acid boracic acid lithium
When higher than 4%, the storage gas generation property of lithium ion battery can be deteriorated, and increase manufacturing cost.
According to an embodiment of the present application, above-mentioned electrolyte can also include lithium salts, and the type of the lithium salts is not particularly limited,
As long as can guarantee electrolyte conductivity with higher, those skilled in the art can according to need flexible choice.In this Shen
In some embodiments please, the lithium salts is selected from one of inorganic lithium salt and organic lithium salt or a variety of.The inorganic lithium salt can
To include but is not limited to lithium hexafluoro phosphate (LiPF6), difluorophosphate (LiPO2F2), LiBF4 (LiBF4), hexafluoroarsenate
One of lithium and lithium perchlorate are a variety of, the organic lithium salt can include but is not limited to double fluorine sulfimide lithiums (LiFSI),
Double trifluoromethanesulfonimide lithiums (LiTFSI), trifluoromethanesulfonic acid lithium (LiCF3SO3) and two (trimethyl fluoride sulfonyl) imine lithiums
(LiN(CF3SO2)2) one of or it is a variety of.Above-mentioned lithium salts transmission lithium ion ability is strong, guarantee electrolyte lithium with higher from
Electron conductivity, electrochemical stability and chemical stability are good, are soluble in organic solvent, are easy to dissociate, decomposition product is to environment
Influence is smaller, has environmental-friendly performance, and is easy to purify and prepare, and price is lower.
In some embodiments of the present application, the lithium salts is selected from lithium hexafluoro phosphate (LiPF6), difluorophosphate
(LiPO2F2), LiBF4 (LiBF4), hexafluoroarsenate lithium, lithium perchlorate, double fluorine sulfimide lithiums (LiFSI), double fluoroforms
One of alkane sulfimide lithium (LiTFSI) is a variety of.In some specific embodiments of the application, the lithium salts is hexafluoro
Lithium phosphate (LiPF6).The transmission lithium ion ability of lithium salts is strong as a result, guarantees electrolyte lithium ion conductivity with higher, electricity
Chemical stability and chemical stability are good, are soluble in organic solvent, are easy to dissociate, and decomposition product has fewer environmental impacts, tool
There is environmental-friendly performance, and be easy to purify and prepare, price is lower.
According to an embodiment of the present application, the concentration of the lithium salts is not particularly limited, as long as meeting needs, art technology
Personnel can be with flexible choice.In some embodiments of the present application, the concentration of lithium salts is 0.5mol/L~1.5mol/L, in this Shen
In other embodiments please, the concentration of lithium salts is 0.8mol/L~1.2mol/L.The concentration of lithium salts is within the above range as a result,
It can guarantee electrolyte lithium ion conductivity with higher, and modest viscosity, cost is relatively low.
According to an embodiment of the present application, above-mentioned electrolyte can also include organic solvent, and the type of the organic solvent does not have
Especially limitation, as long as can satisfy needs, those skilled in the art can be with flexible choice.In some embodiments of the present application,
The organic solvent is selected from ethylene carbonate, propene carbonate, butylene, methyl ethyl carbonate, dimethyl carbonate, carbonic acid two
Ethyl ester, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonic acid ester, 1,4- butyrolactone, methyl propionate, methyl butyrate, ethyl acetate,
One of ethyl propionate and ethyl butyrate are a variety of.The organic solvent viscosity and dielectric constant selected as a result, are moderate, thermostabilization
Property it is good, use temperature range is wide, and chemistry and chemical property are good, safety and high with the compatibility of environment, and price is low.
According to an embodiment of the present application, the preparation method of electrolyte is not particularly limited, and those skilled in the art can root
According to needing flexible choice.In some specific embodiments of the application, electrolyte is using the conventional side for mixing each material
Method is made.Preparation method is simple as a result, it is easy to accomplish, easy to operate, cost is relatively low.
In the another aspect of the application, this application provides a kind of batteries.According to an embodiment of the present application, the battery pack
Include mentioned-above electrolyte.It has the advantages of simple structure and easy realization as a result, it is at low cost, mentioned-above electrolyte is applied to battery
In, additive can form SEI film in the anode surface of battery, and the fluorochemical in electrolyte can be formed in electrode surface
Liquid film is protected, the two, which acts synergistically, can be effectively improved the cycle performance of battery, and the service performance of battery is made to obtain improving simultaneously benefit
In marketing.
According to an embodiment of the present application, the lithium ion battery further includes the positive plate containing positive electrode active materials, contains
The negative electrode tab and isolation film of negative electrode active material.Wherein, the specific type of the negative electrode active material is not particularly limited, this
Field technical staff can according to need flexible choice.In some embodiments of the present application, the negative electrode active material is selected from
Natural graphite, artificial graphite, carbonaceous mesophase spherules (MCMB), hard carbon, soft carbon, silicon, silico-carbo compound, Li-Sn alloy, Li-
Sn-O alloy, Sn, SnO, SnO2, spinel structure lithiumation TiO2-Li4Ti5O12, one of Li-Al alloy or a variety of；Institute
The specific type for stating positive electrode active materials is not particularly limited, and those skilled in the art can according to need flexible choice.At this
In some embodiments of application, positive electrode active materials include but is not limited to cobalt acid lithium, lithium nickelate, LiMn2O4, nickel ion doped, nickel cobalt
One of sour lithium, LiFePO4, nickel cobalt lithium aluminate and nickle cobalt lithium manganate are a variety of, and the above positive electrode active materials include existing skill
Positive electrode active materials in art through overdoping or cladding processing.The material for forming isolation film is not particularly limited, this field
Technical staff can according to need flexible choice.In some embodiments of the present application, isolation film includes polyethylene (PE) isolation
Film, polypropylene (PP) isolation film etc..In addition, according to isolation film surface whether the classification containing coating and coating, isolation film includes
Without one of the naked isolation film of coat, coating inorganic particles isolation film and polymer-coated isolation film or a variety of.It ties as a result,
Structure is simply easily achieved, and selects the battery of above-mentioned anode, negative electrode material and isolation film at low cost, and stability is good, service performance
It is good.
According to an embodiment of the present application, in general battery, the guarantor that is formed using liquid polymer molecule in electrode surface
Cuticula protects the component in electrolyte not to be decomposed, and can only alleviate the decomposition of electrolyte to a certain extent, can not be obvious
Improve the cycle performance and service performance of battery, and then is not able to satisfy the needs in market.And by electrolyte in the application
Composition is adjusted, at the same joined in the electrolytic solution can electrode surface formed protection liquid film fluorochemical and can be with
The additive of stable SEI film is formed in battery forming process middle-jiao yang, function of the spleen and stomach pole surface, to inhibit electrolyte in point of electrode surface
Solution, so that the cycle performance of battery is obviously improved, service performance is improved, and effectively meets the needs of existing market, is improved and is used
Family experience.
Embodiment
According to following preparation method, formed shown in table 1, prepare the lithium of embodiment 1-17 and comparative example 1-18 from
Sub- battery, specific as follows:
Preparation method:
1, lithium ion battery is formed
(1) prepared by positive plate
By positive electrode active materials cobalt acid lithium (LiCoO2), conductive agent Super P, binder polyvinylidene fluoride is according to weight
It is mixed, is added N-Methyl pyrrolidone (NMP) than 97:1.4:1.6, stirring to system obtains anode at transparent and homogeneous shape
Slurry；Anode sizing agent is evenly applied on plus plate current-collecting body aluminium foil；Aluminium foil is dried at 85 DEG C, then by cold pressing, sanction
After piece, cutting, it is dried to obtain positive plate.
(2) prepared by negative electrode tab
By negative electrode active material artificial graphite, conductive agent Super P, thickener sodium carboxymethylcellulose (CMC), binder
Butadiene-styrene rubber (SBR) is mixed according to weight ratio 96.4:1.5:0.5:1.6, and deionized water, stirring to obtain cathode slurry is added
Material；Negative electrode slurry is coated uniformly on negative current collector copper foil；Copper foil is dried at 85 DEG C, then by cold pressing, cut-parts,
After cutting, it is dried to obtain negative electrode tab.
(3) prepared by electrolyte
In dry argon atmosphere glove box, by ethylene carbonate (EC), methyl ethyl carbonate (EMC), diethyl carbonate
(DEC) it is that EC:EMC:DEC=30:50:20 is mixed according to mass ratio, additive is subsequently added into, after dissolving and being sufficiently stirred
Lithium salts LiPF is added6, electrolyte is obtained after mixing.Wherein, LiPF6Concentration be 1.05mol/L.It is used in electrolyte
Other electrolysis additives specific type and content it is as shown in table 1.In table 1, the content of electrolysis additive is base
In the mass percent that the gross mass of electrolyte is calculated.
(4) preparation of isolation film
Select polyethylene (PE) isolation film of 16 μ m-thicks.
(5) preparation of lithium ion battery
Positive plate, isolation film, negative electrode tab are folded in order, isolation film is between positive and negative plate and plays isolation
Effect, then winding obtains naked battery core；The above-mentioned electrolyte prepared is injected into the battery core after drying, by vacuum seal
Dress, stand, chemical conversion (0.02C constant-current charge to 3.3V, then with 0.1C constant-current charge to the processes such as 3.6V), shaping, volume test,
Obtain soft bag lithium ionic cell.
Additive types and dosage in the electrolyte of table 1 embodiment 1-17 and comparative example 1-18
2, performance of lithium ion battery test process
(1) cycle performance of lithium ion battery is tested
Lithium ion battery is placed in 25 DEG C of insulating boxs, 30 minutes is stood, lithium ion battery is made to reach constant temperature.It is up to perseverance
The lithium ion battery of temperature is 4.3V with 0.7C constant-current charge to voltage, is then 0.05C with 4.3V constant-voltage charge to electric current, then
It is 3.0V with 1C constant-current discharge to voltage, this is a charge and discharge cycles.Capacity to discharge for the first time is repeated for 100%
Charge and discharge cycles record circulating ring number until stopping test when discharge capacity decays to 80%, follow as evaluation lithium ion battery
The index of ring performance, test result are shown in Table 2.
Cycle performance of the lithium ion battery at 45 DEG C is tested simultaneously, test method is tested with above-mentioned 25 DEG C of cycle performances, is surveyed
Test result is shown in Table 2.
(2) high-temperature lithium ion battery storage test
Lithium ion battery is placed in 25 DEG C of insulating boxs, 30 minutes is stood, lithium ion battery is made to reach constant temperature.With 0.5C perseverance
For current charge to 4.4V, constant-voltage charge to electric current is 0.05C, then with 0.5C constant-current discharge to 3.0V, records discharge capacity, as
Lithium ion battery initial capacity.Later with 0.5C constant-current charge to 4.4V, constant-voltage charge to electric current is 0.05C, tests and records
The thickness of battery.Test lithium ion battery is gone in 60 DEG C of insulating boxs and carries out storage 21 days, during which tested and recorded every 3 days
Cell thickness is primary, transfers battery in 25 DEG C of insulating boxs after storage in 21 days, 60 minutes is stood, with 0.5C constant-current discharge
To 3.0V, discharge capacity is recorded, as lithium ion battery residual capacity.It calculates lithium ion battery and stores thickness swelling, and make
The index of gas production is stored for evaluation high-temperature lithium ion battery, test result is shown in Table 2.
Wherein, thickness swelling=(21 days thickness-original depths of storage)/original depth * 100%
(3) lithium ion battery first charge-discharge efficiency
Head effect=discharge capacity/initial charge capacity * 100% for the first time, test result is shown in Table 2.
The performance of lithium ion battery test result of table 2 embodiment 1-17 and comparative example 1-18
3, interpretation of result
From the data analysis in Tables 1 and 2 it is found that from comparative example 1 and comparative example 2-9 it is found that be added VC, FEC,
One or more of LiBOB, LiODFB can be obviously improved the cycle performance and head effect of lithium ion battery, meanwhile, it does not dislike
Change storage performance.But in order to give the better consumption experience of consumer, there is still a need for do further to mention for the cycle performance of lithium ion battery
It rises.
It is found that one or more of perfluoropolyether and perfluor dodecane is added from comparative example 1 and comparative example 10-12,
It can obviously improve the cycle performance of lithium ion battery, meanwhile, do not deteriorate storage performance.Equally, the cyclicity of lithium ion battery
It can there is still a need for promotions.
From in comparative example 2-12 and embodiment 1-17 it is found that by least one of perfluoropolyether and perfluor dodecane with
At least one of VC, FEC, LiBOB, LiODFB are combined, can be at least one be individually added into perfluoropolyether and perfluor dodecane
The cycle performance of lithium ion battery is further promoted on the basis of at least one of kind or VC, FEC, LiBOB, LiODFB, meanwhile,
Hardly deteriorate storage performance.
It is found that when the molecular weight of perfluoropolyether is close from embodiment 1,18,19, performance of lithium ion battery is changed
Kind effect is hardly influenced by its molecular structure.
From comparative example 13-16 and embodiment 1,3,5,7 it is found that when VC additional amount is more than 5%, severe exacerbation lithium ion
The storage performance of battery；When FEC additional amount is more than 20%, the storage performance of severe exacerbation lithium ion battery；LiBOB additional amount is super
When 5%, the storage performance of severe exacerbation lithium ion battery；When LiODFB additional amount is more than 5%, severe exacerbation lithium ion battery
Storage performance.
When the additional amount of perfluoropolyether or perfluor dodecane is more than 2% known to from comparative example 17-18 and embodiment 1-2
When, the serious first charge-discharge efficiency for reducing lithium ion battery.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example
Point is contained at least one embodiment or example of the application.In the present specification, schematic expression of the above terms are not
It must be directed to identical embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be in office
It can be combined in any suitable manner in one or more embodiment or examples.In addition, without conflicting with each other, the skill of this field
Art personnel can tie the feature of different embodiments or examples described in this specification and different embodiments or examples
It closes and combines.
Although embodiments herein has been shown and described above, it is to be understood that above-described embodiment is example
Property, it should not be understood as the limitation to the application, those skilled in the art within the scope of application can be to above-mentioned
Embodiment is changed, modifies, replacement and variant.
Claims (12)
1. a kind of electrolyte, comprising:
Fluorochemical；And
Additive.
2. electrolyte according to claim 1, wherein the fluorochemical is in perfluoropolyether and perfluoro alkane
It is one or more.
3. electrolyte according to claim 1, wherein the additive is selected from vinylene carbonate, fluoro ethylene carbonate
One of rouge, dioxalic acid lithium borate and difluorine oxalic acid boracic acid lithium are a variety of.
4. electrolyte according to claim 1, wherein the fluorochemical is in a liquid state at room temperature, and boiling point is not low
In 80 degrees Celsius.
5. electrolyte according to claim 1, wherein the gross mass based on the electrolyte, the fluorochemical
Mass fraction is 0.01%~2%.
6. electrolyte according to claim 2, wherein the perfluoropolyether is selected from one of the following or a variety of:
Wherein, m and n respectively may be the same or different, and indicate to be greater than 1 integer.
7. electrolyte according to claim 2, wherein the molecular weight of the perfluoropolyether is greater than 400.
8. electrolyte according to claim 2, wherein the chemical formula of the perfluoro alkane are as follows:
CxF2x+2Formula 5
Wherein, x is selected from the integer greater than 5.
9. electrolyte according to claim 3, wherein the gross mass based on the electrolyte, the vinylene carbonate
Mass fraction be 0.1%~4%, the mass fraction of the fluoro ethylene carbonate is 0.5%~20%, the dioxalic acid boron
The mass fraction of sour lithium is 0.1%~4%, and the mass fraction of the difluorine oxalic acid boracic acid lithium is 0.1%~4%.
10. electrolyte according to claim 1, wherein the electrolyte further includes lithium salts, and the lithium salts is selected from inorganic lithium
One of salt and organic lithium salt are a variety of；
Preferably, the lithium salts be selected from lithium hexafluoro phosphate, difluorophosphate, LiBF4, hexafluoroarsenate lithium, lithium perchlorate,
One of double fluorine sulfimide lithiums, double trifluoromethanesulfonimide lithiums are a variety of；
It is further preferred that the lithium salts is lithium hexafluoro phosphate.
11. electrolyte according to claim 1, wherein the electrolyte further includes organic solvent, the organic solvent choosing
From ethylene carbonate, propene carbonate, butylene, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, carbonic acid dipropyl
Ester, methyl propyl carbonate, ethyl propyl carbonic acid ester, 1,4- butyrolactone, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate and butyric acid
One of ethyl ester is a variety of.
12. a kind of battery, wherein including electrolyte of any of claims 1-11.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112002943A (en) * | 2020-09-10 | 2020-11-27 | 中国科学院过程工程研究所 | Electrolyte and preparation method and application thereof |
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|---|---|---|---|---|
| CN1739208A (en) * | 2003-01-23 | 2006-02-22 | 索尼株式会社 | Electrode and battery |
| US20070048622A1 (en) * | 2005-08-24 | 2007-03-01 | Jae-Gu Yoon | Organic electrolytic solution and lithium battery using the same |
| CN102598389A (en) * | 2009-06-24 | 2012-07-18 | 丰田自动车工程及制造北美公司 | High voltage electrolyte |
| CN105098235A (en) * | 2014-04-15 | 2015-11-25 | 东莞新能源科技有限公司 | Lithium ion secondary battery and electrolyte thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1739208A (en) * | 2003-01-23 | 2006-02-22 | 索尼株式会社 | Electrode and battery |
| US20070048622A1 (en) * | 2005-08-24 | 2007-03-01 | Jae-Gu Yoon | Organic electrolytic solution and lithium battery using the same |
| CN102598389A (en) * | 2009-06-24 | 2012-07-18 | 丰田自动车工程及制造北美公司 | High voltage electrolyte |
| CN105098235A (en) * | 2014-04-15 | 2015-11-25 | 东莞新能源科技有限公司 | Lithium ion secondary battery and electrolyte thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112002943A (en) * | 2020-09-10 | 2020-11-27 | 中国科学院过程工程研究所 | Electrolyte and preparation method and application thereof |
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