Art
[1]
Mutual citations and related application (s)
[2]
This application claims the benefit of priority based on 112 dates Korea Patent Application No. 2017-0005599, and No. 112 dated Korea Patent Application No. 2018-0004665 May 2018 May 2017, all described in the literature of the Korea Patent Application content of which is incorporated as a part hereof.
[3]
[4]
Art
[5]
The present invention relates to a lithium secondary battery comprising this composition and a high temperature for the safety is improved gel polymer electrolyte.
BACKGROUND
[6]
Recently, increasing interest in energy storage technology. In particular, mobile phones, camcorders and notebook PC, and further as its application has expanded to the electric car, it is increasingly embodied a commitment to research and development of energy-saving technologies.
[7]
The electrochemical device is a field in the most attention among these energy storage technology, particularly there is emerging interest in the secondary battery can be charged and discharged.
[8]
The lithium secondary battery developed in the early 1990s from the secondary battery that is currently being applied has been highlighted in a high working voltage is much greater energy density points.
[9]
The conventional secondary battery has been mainly used ion conductive non-aqueous electrolytic solution obtained by dissolving the salt in a non-aqueous organic solvent.
[10]
However, the non-aqueous electrolyte has a disadvantage that the electrode material is degenerated as well as the most likely to be a volatile organic solvent, safety is low by the combustion caused by temperature rise of ambient temperature, and the battery itself. In particular, there is a problem in that the gas is generated to expand the cell thickness in the cell interior by a side reaction and decomposition and / or an organic solvent and an electrode of a carbonate organic solvent during charging and discharging.
[11]
This non-aqueous gel polymer electrolyte proposed in order to improve the disadvantage of the electrolyte as well as to keep constant the thickness of the battery is excellent in electrochemical stability, the gel because due to its own adhesive force excellent contact between the electrode and the electrolyte film- It has been used in battery manufacturing.
[12]
Manufacturing method of a secondary battery applying the gel polymer electrolyte may have two methods are known as follows.
[13]
First, after the salt is prepared by mixing the for the gel-forming composition of the polymerizable monomer and a polymerization initiator in the melted non-aqueous organic solvent, and pouring it into a positive electrode, a negative electrode, and battery separators is that contains the wound or laminated electrode assembly , followed by gelling (crosslinking), under suitable temperature and time conditions, it is possible to prepare a secondary battery containing a gel polymer electrolyte. However, the method has the disadvantage of low stability at the time of the heating process for wettability (wetting) and gelling (gelation).
[14]
Another method, a method for producing a positive electrode, a negative electrode coated with a gel polymer electrolyte composition of the membrane surface and then, by heat or that gelation by using a UV, and then combining this cell, and add a conventional electrolyte is injected. The method is a situation that does not satisfy in terms of performance as well as thermal stability of the secondary battery because it further comprises a non-aqueous organic solvent.
[15]
Thus, there is a need for the development of the gel polymer electrolyte with improved performance such as wettability and high temperature stability.
[16]
[17]
Prior Art Document
[18]
Korea Patent Laid-Open Publication No. 2015-0125928 No.
Detailed Description of the Invention
SUMMARY
[19]
The present invention has been made in view of solving the above problems.
[20]
The first object of the present invention is to provide a wettability and a high temperature stability is improved composition for gel polymer electrolytes.
[21]
A second object of the present invention is to provide a gel polymer electrolyte formed by polymerization of a composition for the gel polymer electrolyte.
[22]
Further, a third object of the present invention is that by including the gel polymer electrolyte, provides an improved high-temperature safety of lithium secondary battery.
Problem solving means
[23]
In order to solve the above problems, in the embodiment of the present invention
[24]
A lithium salt;
[25]
The non-aqueous organic solvent;
[26]
To the oligomer represented by formula (1); And
[27]
It provides for a gel polymer electrolyte composition including a; a polymerization initiator.
[28]
Formula 1
[29]
[30]
In the formula 1,
[31]
R 1 to R 3 are each independently substituted with fluorine or unsubstituted alkylene group having 1 to 4 rings,
[32]
R 4 and R 5 are each independently an aliphatic hydrocarbon group or aromatic hydrocarbon group,
[33]
R 6 and R 7 are independently an alkyl group or a group having 1 to 10 carbon atoms each , and wherein R 8 and R 9 are independently an alkyl group or a group having 1 to 10 carbon atoms each , and
[34]
R 10 is an aliphatic hydrocarbon group or aromatic hydrocarbon group,
[35]
R 11 is an alkylene group having 1 to 3 carbon atoms,
[36]
R 12 is hydrogen or an alkyl group having 1 to 2;
[37]
N is any integer of 1 to 70,
[38]
m is any integer of 1 to 3.
[39]
[40]
In the oligomer of formula (1), the aliphatic hydrocarbon group may contain an alicyclic hydrocarbon group or linear hydrocarbon.
[41]
The alicyclic hydrocarbon group is a small number cycloalkylene group of substituted or unsubstituted 4 to 20 carbon atoms; Isocyanate group-cycloalkylene group of substituted or unsubstituted 4 to 20 carbon atoms containing a (NCO); Cycloalkenyl group substituted or unsubstituted 4 to 20 carbon atoms; And there may be mentioned a substituted or unsubstituted at least one or more selected from the group consisting of unsubstituted heterocycloalkyl alkylene having 2 to 20 carbon atoms.
[42]
The linear hydrocarbon group is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Isocyanate group-containing substituted (NCO) or unsubstituted alkylene group having 1 to 20 carbon atoms; Xylene alkoxyl group of substituted or unsubstituted C1 to C20; Substituted or unsubstituted alkenylene group of 2 to 20 carbon atoms; And there may be mentioned at least one or more selected from the substituted or non-substituted alkynylene group the group consisting of a ring having 2 to 20 carbon atoms.
[43]
Also, in the oligomer of the formula (1), the aromatic hydrocarbon group is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or there may be mentioned a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
[44]
[45]
Specifically, an oligomer represented by the formula (1) can be given to an oligomer of the formula 1a.
[46]
[Chemical Formula 1a]
[47]
[48]
In Formula 1a,
[49]
R 4 and R 5 is an aliphatic hydrocarbon group, each independently,
[50]
R 8 and R 9 are each independently a,
[51]
R 10 is an aliphatic hydrocarbon group, R 11 is an alkylene group having 1 to 3 carbon atoms,
[52]
R 12 is hydrogen or an alkyl group having 1 to 2;
[53]
N is any integer of from 10 to 20,
[54]
m is any integer of 1 to 2.
[55]
[56]
More specifically, the oligomer represented by the formula (1a) may be an oligomer represented by the formula 1a-1 to.
[57]
[Chemical Formula 1a-1]
[58]
[59]
In the formula 1a-1,
[60]
n is any integer of from 10 to 20.
[61]
[62]
Formula 1 represented oligomer may be included in total based on the weight of a 0.5% by weight to 20% by weight of the composition for gel polymer electrolyte, in particular 0.5% to 10% by weight.
[63]
Further, the weight average molecular weight (MW) of the oligomer represented by the formula (1) is 1,000 g / mol to about 10,000 g / mol, specifically 3,000 g / mol to about 8,000 g / mol, and more particularly 3,000 g / mol to about 5,000 g / mol may be.
[64]
[65]
Further, one embodiment of the present invention, provides a gel polymer electrolyte formed by polymerizing the above-mentioned gel polymer electrolyte composition under an inert atmosphere.
[66]
[67]
In one embodiment of the present invention
[68]
It provides a separator, and a lithium secondary battery including the gel polymer electrolyte of the present invention interposed between the negative electrode, a positive electrode, the negative electrode and the positive electrode.
Effects of the Invention
[69]
According to one embodiment of the present invention by including an oligomer having a hydrophilic and a hydrophobic functional group may be a wetting composition for preparing the gel polymer electrolyte having enhanced. Further, by using this, a low surface tension of the electrode surface, it is possible during the initial charge to form a stable ion conductive coating film on the electrode surface to provide a gel polymer electrolyte which can prevent the electrolyte side reactions. Furthermore, the present invention can be manufactured according to the improved high temperature stability of lithium secondary batteries by providing such a gel polymer electrolyte.
Brief Description of the Drawings
[70]
Following figures attached to this specification are intended to illustrate preferred embodiments of the present invention, the components which serve to further understand the teachings of the present invention with the content of the above-described invention, the invention is only to details set forth in those figures It is limited and are not to be construed.
[71]
Figure 1 is a graph showing the high-temperature safety of the secondary battery according to the measurement results of Experimental Example 1 of the present invention.
Best Mode for Carrying Out the Invention
[72]
A detailed explanation follows below with more detail the present invention.
[73]
Herein and in the terms or words used in the claims is general and not be construed as limited to the dictionary meanings are not, the inventor can adequately define terms to describe his own invention in the best way on the basis of the principle that the interpreted based on the meanings and concepts corresponding to technical aspects of the present invention.
[74]
A "*", unless otherwise specified in the present invention refers to a connected part between the same or different atom or an end portion of the formula.
[75]
[76]
One embodiment of the present invention,
[77]
The non-aqueous organic solvent;
[78]
A lithium salt;
[79]
To the oligomer represented by formula (1); And
[80]
It provides for a gel polymer electrolyte composition including a; a polymerization initiator.
[81]
Formula 1
[82]
[83]
In the formula 1,
[84]
R 1 to R 3 are each independently substituted with fluorine or unsubstituted alkylene group having 1 to 4 rings,
[85]
R 4 and R 5 are each independently an aliphatic hydrocarbon group or aromatic hydrocarbon group,
[86]
R 6 and R 7 are independently an alkyl group or a group having 1 to 10 carbon atoms each , and wherein R 8 and R 9 are independently an alkyl group or a group having 1 to 10 carbon atoms each , and
[87]
Wherein R 10 is an aliphatic hydrocarbon group or aromatic hydrocarbon group,
[88]
R 11 is an alkylene group having 1 to 3 carbon atoms,
[89]
R 12 is hydrogen or an alkyl group having 1 to 2;
[90]
N is any integer of 1 to 70,
[91]
m is any integer of 1 to 3.
[92]
[93]
In this case, the group in the oligomer of the formula (1), wherein the aliphatic hydrocarbon group may comprise a cycloaliphatic hydrocarbon group or linear hydrocarbon.
[94]
The alicyclic hydrocarbon group is a small number cycloalkylene group of substituted or unsubstituted 4 to 20 carbon atoms; Isocyanate group-cycloalkylene group of substituted or unsubstituted 4 to 20 carbon atoms containing a (NCO); Cycloalkenyl group substituted or unsubstituted 4 to 20 carbon atoms; And there may be mentioned a substituted or unsubstituted at least one or more selected from the group consisting of unsubstituted heterocycloalkyl alkylene having 2 to 20 carbon atoms.
[95]
The linear hydrocarbon group is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Isocyanate group-containing substituted (NCO) or unsubstituted alkylene group having 1 to 20 carbon atoms; Xylene alkoxyl group of substituted or unsubstituted C1 to C20; Substituted or unsubstituted alkenylene group of 2 to 20 carbon atoms; And there may be mentioned at least one or more selected from the substituted or non-substituted alkynylene group the group consisting of a ring having 2 to 20 carbon atoms.
[96]
Also, in the oligomer of the formula (1), the aromatic hydrocarbon group is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or there may be mentioned a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
[97]
[98]
Specifically, an oligomer represented by the formula (1) can be given to an oligomer of the formula 1a.
[99]
[Chemical Formula 1a]
[100]
[101]
In Formula 1a,
[102]
R 4 and R 5 is an aliphatic hydrocarbon group, each independently,
[103]
R 8 and R 9 are each independently a,
[104]
R 10 is an aliphatic hydrocarbon group, R 11 is an alkylene group having 1 to 3 carbon atoms,
[105]
R 12 is hydrogen or an alkyl group having 1 to 2;
[106]
N is any integer of from 10 to 20,
[107]
m is any integer of 1 to 2.
[108]
[109]
More specifically, the oligomer represented by the formula (1a) may be an oligomer represented by the formula 1a-1 to.
[110]
[Chemical Formula 1a-1]
[111]
[112]
In the formula 1a-1,
[113]
n is any integer of from 10 to 20.
[114]
[115]
In the present composition for the gel polymer electrolyte of the invention, an oligomer of the formula (1) it is positive at the terminal at the same time containing a hydrophilic segment of an acrylate-based functional group which can form crosslinks by itself, and the hydrophobic part of the fluorine-substituted ethylene group because they contain, it is possible to give a surface active agent (surfactant) function within the cell to lower the surface resistance of the electrode interface. Therefore, for the gel polymer electrolyte composition comprising an oligomer of the formula (1) it can be improved than the wetting effect. In addition, by an oligomer of the formula (1) is comprising a primary amide group (amide group) and highly stable fluorinated ethylene electrochemically in the structure of chain units, a lithium ion (Li + side reaction, and a lithium salt of a) (salt) of it is possible to control the decomposition reaction, CO or CO at the time of overcharge 2 can reduce the gas generation and the like. Using these for the gel polymer electrolyte composition having excellent mechanical properties and thermal, chemical and oxidative stability, low surface tension of the electrode surface, it can form a stable ion conductive film at the time of initial charging electrode surface to prevent the electrolyte side reaction the gel polymer electrolyte can be produced in, and has a high temperature stability can be prepared by an improved lithium secondary battery comprising the same.
[116]
[117]
According to one embodiment of the invention, an oligomer of the formula (1) it may be included in, based on the total weight of the composition for gel polymer electrolyte having a 0.5% by weight to 20% by weight, in particular 0.5% to 10% by weight. If, the disadvantage that if If the content of the oligomer is less than 0.5% by weight and the gel reaction forming effect of the total electrolyte is insufficient, the amount of oligomer is more than 20% by weight is contained excess oligomers and the resistance increases and the ionic conductivity decreases It may occur.
[118]
[119]
Further, according to one embodiment of the invention, the weight average molecular weight (MW) of the oligomer represented by the formula (1) can be adjusted by the number of repeat units, from about 1,000 g / mol to about 10,000 g / mol, specifically 3,000 g / mol to about 8,000 g / mol, and more specifically can be 3,000 g / mol to about 5,000 g / mol days.
[120]
When the weight average molecular weight of said oligomer is within the above range, it is possible to effectively improve the mechanical strength of the battery comprising the same.
[121]
If, because of the weight average molecular weight of the oligomer group 1,000 g / mol is less than, the hard polymer matrix form when the gel reaction proceeds, can be reduced in the electrolyte side reaction suppression effect. When the weight average molecular weight of the oligomer exceeds 10,000 g / mol, the properties of the oligomer itself is stiff (rigid), as well as lower the electrolyte solvent and the affinity to be dissolved is difficult and also increases its viscosity, some dissolved electrolyte Initial greatly disappointed down the battery electrolyte wettability, it can lead to degradation of the secondary battery.
[122]
The weight average molecular weight is one having a molecular weight unless specified otherwise the terms may mean the figures, particularly of the standard polystyrene as measured by GPC (Gel Permeation Chromatograph) may mean the weight average molecular weight. For example, the present invention, measured with a Agilent 1200 Series GPC 社 condition, wherein the column can be used for the Agilent 社 PL mixed B columns used, the solvents can be used to THF.
[123]
[124]
On the other hand, the lithium salt contained in the composition for gel polymer electrolyte according to an embodiment of the present invention can be used without limitation, those which are commonly used in a lithium secondary battery electrolyte, such as Li in the cation + contains the anion as F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF 6 - , AsF 6 - , BF 2 C 2 O 4 - , BC 4 O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , C 4 F 9 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (F 2 SO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - and ( CF 3 CF 2 SO 2 ) 2 N - can include at least one selected from the group consisting of. The lithium salt according to one or required may be used by mixing two or more. The lithium salt used in conventional range can be appropriately changed within However, in order to obtain the best corrosion resistant film-forming effect of the electrode surface, 0.8 M to about 2M, specifically, a concentration of 0.8M to 1.5M in the gel polymer electrolyte composition of It may include a.
[125]
[126]
In addition, the non-aqueous organic solvent contained in the composition for gel polymer electrolyte according to an embodiment of the present invention may be a decomposition due to oxidation minimized in the charge-discharge process of the secondary battery, it can exhibit the desired properties with the additives so long as there are no restrictions. For example, each may be mixed alone, or two or more kinds of ether solvents, ester solvents, amide solvents, or the like.
[127]
In an ether solvent of said organic solvent is dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, available methyl propyl ether, and any one or a mixture of two or more of those selected from the group consisting of: ethyl propyl ether, but , and the like.
[128]
In addition, the ester solvent may include at least one or more compounds selected from the cyclic carbonate compound, a linear carbonate compound, a linear ester compound, the group consisting of a cyclic ester compound.
[129]
Specific examples of double the cyclic carbonate compound is ethylene carbonate (ethylene carbonate, EC), propylene carbonates (propylene carbonate, PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate , 2,3-pen there is any one or a mixture of two or more of those selected from ethylene carbonate, vinylene carbonate, and the group consisting of ethylene carbonate (FEC) fluoro.
[130]
Further, specific examples of the linear carbonate compounds include the group consisting of dimethyl carbonate (dimethyl carbonate, DMC), diethyl carbonate (diethyl carbonate, DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate and ethyl propyl carbonate the one or the like of two or more of a mixture thereof is selected from may be used as a representative, and the like.
[131]
The linear ester compound two of any one thereof is selected from the specific examples of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate group consisting of or more such as the mixture may be used as a representative, and the like.
[132]
The cyclic ester compound is the specific example γ- butyrolactone, two or more of any one or combinations selected from a lactone, γ- caprolactone, lactone, such as the group consisting of ε- caprolactone as σ- ballet as γ- ballet species the mixture can be used for, but is not limited to this.
[133]
The cyclic carbonate compound in an ester solvent may be used preferably because good dissociate a lithium salt in a high dielectric constant is used as the organic solvent having a high viscosity electrolyte, a low viscosity such as this cyclic carbonate compound as dimethyl carbonate and diethyl carbonate, a numeral that using a mixture of dielectric constant linear carbonate compound and linear ester compound in an appropriate ratio can make a gel polymer electrolyte having high electric conductivity may be used more preferably.
[134]
[135]
Further, in the composition for gel polymer electrolyte according to an embodiment of the present invention, the polymerization initiator may be used conventional polymerization initiators known in the art. For example, the typical examples of the polymerization initiator, benzoyl peroxide (benzoyl peroxide), acetyl peroxide (acetyl peroxide), dilauryl peroxide (dilauryl peroxide), di -tert- butyl peroxide (di-tert-butyl peroxide ), t- butyl peroxy-2-ethyl-hexanoate (t-butyl peroxy-2-ethyl-hexanoate), cumyl hydroperoxide (cumyl hydroperoxide) and hydrogen peroxide (organic peroxides, such as hydrogen peroxide) or peroxides hydrochloride and 2,2'-azobis (2-cyano-butane), dimethyl 2,2'-azobis (2-methylpropionate), 2,2'-azobis (methylbutyronitrile) , 2,2'-azobis (isobutyronitrile) (AIBN; 2,2'-azobis (iso-butyronitrile)) and 2,2'-azo-bis-dimethyl-valeronitrile (AMVN; 2,2 & apos; but one or more species, such as azo compounds selected from the group consisting of Azobisdimethyl-Valeronitrile), but not always limited thereto.
[136]
The polymerization initiator is decomposed in the heat, but not limited 30 ℃ to 100 ℃, particularly decomposition by heat of 60 ℃ to 80 ℃ or room temperature (5 ℃ to 30 ℃) within the cell to form a radical, a free radical polymerization and a polymerizable oligomer may be formed by reacting the gel polymer electrolyte.
[137]
The polymerization initiator may be included in amount of 0.1 parts by weight to 5 parts by weight per 100 parts by weight of the oligomer. When the above polymerization initiator exceeds 5 parts by weight, the unreacted polymerization initiator remaining in the gel polymer electrolyte produced upon mijil may adversely affect the battery performance. Conversely, the polymerization initiator has a problem that the support is well-made gelled in less than 0.1 part by weight or more when certain temperature conditions.
[138]
[139]
On the other hand, lithium secondary batteries gel polymer electrolyte composition according to an embodiment of the present invention may further include additional additives as needed. In addition, the additive can be used in the present invention is mixed vinylene carbonate, vinyl ethylene carbonate, fluoro-ethylene carbonate, vinyl ethylene carbonate, cyclic sulfite, saturated sultone, unsaturated sultone, non-annular sulfone, etc., each alone or in combination and it can be used.
[140]
In this case, the cyclic sulfites include ethylene sulfite, methyl ethylene sulfite, ethyl ethylene sulfite, 4,5-dimethyl ethylene sulfite, 4,5-diethyl ethylene sulfite, propylene sulfite, 4,5-dimethyl propylene sulfite, 4,5-diethyl propylene sulfite, 4,6-dimethyl propylene sulfite, 4,6-diethyl propylene sulfite, 1,3-butylene, and the like, and glycol sulfite, saturated sultone It includes 1,3-propane sultone, 1,4-butane sultone and the like, unsaturated sultone include ethene sultone, 1,3-propene sultone, 1,4-butene sultone, 1-methyl-1,3 -propene sultone and the like, non-cyclic sulfones include divinyl sulfone, and the like, dimethyl sulfone, diethyl sulfone, methyl ethyl sulfone, methyl vinyl sulfone.
[141]
The additional additives may be of two or more thereof is a mixture of 0.01 to 5% by weight based on the total composition for the gel polymer electrolyte, specifically, it may be included in an amount of 0.01 to 3% by weight, preferably 0.05 to 3% by weight. The additional When the content of additives is less than 0.01% by weight when the of the battery low-temperature output improved, and high-temperature storage characteristics and high-temperature cycle life characteristics improving effect insignificant, and the amount of the additional additives is more than 5% by weight of the charge and discharge of the battery when a side reaction in the electrolyte is likely to occur quickly. In particular, mothayeo not sufficiently decomposed at a high temperature at the time of the SEI film-forming additive to be added in excess, there can be, and in the electrolyte at room temperature, there remains unreacted or precipitated. Accordingly, there may occur a side reaction that the life or resistance characteristics of the secondary battery decreases.
[142]
[143]
Further, one embodiment of the present invention, provides a gel polymer electrolyte formed by polymerizing the above-mentioned gel polymer electrolyte composition under an inert atmosphere.
[144]
[145]
In one embodiment of the present invention
[146]
Interposed between the cathode, the anode, the cathode and the anode separator, and
[147]
It provides a rechargeable lithium battery including the gel polymer electrolyte of the present invention.
[148]
[149]
Specifically, the gel polymer electrolyte may be produced by curing reaction after injecting the above-mentioned gel polymer electrolyte composition into the rechargeable battery.
[150]
For example, the gel polymer electrolyte is a gel polymer electrolyte composition for the inside of the secondary battery in-situ may be formed by polymerization.
[151]
More As a specific embodiment, (a) an anode, a cathode, and phase and (b) a gel polymer according to the invention to the cell case of inserting the electrode assembly consisting of a separator interposed between the positive electrode and the negative electrode in a battery case after injecting the electrolyte composition may include the step of polymerizing to form a gel polymer electrolyte.
[152]
The lithium secondary battery within the in-situ polymerization is possible through the electron beam (E-BEAM), gamma ray, room temperature or high temperature aging process, according to one embodiment of the present invention can be carried out through thermal polymerization. At this time, the polymerization time can be about 2 minutes to 12 hours, and may take, heat polymerization temperature is 60 ℃ to 100 ℃, with 60 ℃ to 80 ℃ specifically.
[153]
More specifically, the lithium secondary battery within the in-situ polymerization reaction is injected into the battery cell and then adding and mixing a predetermined amount of the polymerization initiator and the oligomer in the composition for gel polymer electrolyte containing the lithium salt. After sealing the main aekgu of such cells, for example by heating for 1 to 20 hours at 60 ℃ to 80 ℃ performed in the polymerization, as a lithium salt-containing gel polymer electrolyte composition for gel is made of a gel polymer electrolyte.
[154]
The lithium secondary battery according to an embodiment of the present invention is excellent in capacity characteristics of the lithium secondary battery in both the charging voltage is 3.0V to 5.0V range, the line voltage and high-voltage region.
[155]
[156]
Further, it is possible by using a gel polymer electrolyte of the present invention further contain, the total weight of the inorganic particles of 10% to 25% by weight with respect to the gel polymer electrolyte having a case of realizing a coating type gel polymer electrolyte.
[157]
The inorganic particles are impregnated with a polymer network, a high-viscosity solvent through the pores formed by the empty space between the inorganic particles can be well impregnated deuldorok. That is, by including inorganic particles, it is possible to obtain the effect to be further improved the wettability of the high-viscosity solvent by affinity and capillary forces between the polar material.
[158]
These mineral particles have a dielectric constant is high, the operating voltage range of the lithium secondary battery (e.g., Li / Li + can be used inorganic particles of 0 to 5V based) that the oxidation and / or reduction reaction in place.
[159]
[160]
Specifically, the inorganic particles that at least as a representative example the dielectric constant 5 BaTiO 3 , BaTiO 3 , Pb (Zr, Ti) O 3 (PZT), Pb 1 - a La a Zr 1 - b Ti b O 3 (PLZT where, 0
[197]
Example 1
[198]
(Gel polymer electrolyte composition prepared for)
[199]
1M LiPF 6 that the non-aqueous organic solvent soluble (ethylene carbonate (EC): ethyl methyl carbonate (EMC) = 3: 7 volume ratio) of the compound of the formula 1a-1 in 94.8g (n = 10, weight average molecular weight (Mw) : to 3,000 g / mol) 5g, and dimethyl 2,2'-azobis (2-methylpropionate) (CAS No. 2589-57-3) was added to 0.2g composition for gel polymer electrolyte as a polymerization initiator was prepared .
[200]
[201]
(Preparation of lithium secondary battery)
[202]
As a cathode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 ; NCM) 94% by weight, of a conductive material of carbon black (carbon black) 3% by weight of polyvinyl a binder fluoride (PVDF) 3 parts by weight % were added to N- methyl-2-pyrrolidone (NMP) solvent producing a positive electrode active material slurry (solid content 50%). After the positive electrode active material slurry is applied to a thickness approximately the positive electrode collector of aluminum (Al) film of 20㎛ and dried to produce a positive electrode, a positive electrode subjected to a roll press (press roll) was prepared.
[203]
A carbon powder, a binder, a negative electrode active material to PVDF, the conductive material of carbon black (carbon black), respectively 96 wt%, 3 wt% to 1 wt% was added to the solvent NMP negative electrode active material slurry (solid content 80%) It was prepared. After the above is a negative electrode active material slurry was applied to a thickness of the anode current collector, copper (Cu) thin film of 10㎛ and dried to produce a negative electrode, a negative electrode subjected to a roll press (press roll) was prepared.
[204]
By laminating the positive electrode, a negative electrode and a polypropylene / polyethylene / polypropylene (PP / PE / PP) separator consisting of three layers, in order to prepare an electrode assembly.
[205]
The positive electrode, a negative electrode and a polypropylene / polyethylene / polypropylene (PP / PE / PP) produced an electrode assembly with a separator consisting of three layers, and receiving them in a battery case, and the manufacturing gel polymer electrolyte composition was injected .
[206]
Subsequently, it was prepared a rechargeable lithium battery including the following, heat polymerized gel polymer electrolyte for 5 hours by heating at 65 ℃ stored at room temperature for 2 days.
[207]
[208]
Example 2
[209]
At the time of manufacture for the gel polymer electrolyte composition, and the composition for gel polymer electrolyte in a manner similar to that of example 1 except that the addition of non-aqueous organic solvent and a polymerization initiator compound 10g 0.2g of formula 1a-1 wherein in 89.8g It was prepared in a secondary battery including the gel polymer electrolyte using the same.
[210]
[211]
Example 3.
[212]
At the time of manufacture for the gel polymer electrolyte composition, and the composition for gel polymer electrolyte in a manner similar to that of example 1 except that the addition of non-aqueous organic solvent 1g compound of formula 1a-1 wherein the polymerization initiator to 98.98g and 0.02g It was prepared in a secondary battery including the gel polymer electrolyte using the same.
[213]
[214]
Example 4.
[215]
When the gel polymer electrolyte composition prepared for a non-aqueous organic solvent a compound of formula 1a-1 to the 94.8g (weight average molecular weight (Mw): 1,000 g / mol) and is the exception that the addition of 5g and a polymerization initiator 0.2g It was produced in the example 1 and by a method similar to the composition for gel polymer electrolyte and a secondary battery including the gel polymer electrolyte using the same.
[216]
[217]
Example 5.
[218]
When the gel polymer electrolyte composition prepared for, and is described in Example 1 the same manner as the composition and this for the gel polymer electrolyte, except the non-aqueous organic solvent, 78g to the addition of compound 20g and a polymerization initiator 2g of the formula 1a-1 to prepare a secondary battery including the gel polymer electrolyte using.
[219]
[220]
Example 6.
[221]
At the time of manufacture for the gel polymer electrolyte composition, the compound of formula 1a-1 wherein the non-aqueous organic solvent, 94.8g (weight average molecular weight (Mw): 10,000 g / mol) and is the same as example 1 except that the addition of 5g a method to prepare a secondary battery including the gel polymer electrolyte using the composition and for this gel polymer electrolyte.
[222]
[223]
Example 7.
[224]
When the gel polymer electrolyte composition prepared for a non-aqueous compound of formula 1a-1 wherein the organic solvent 99.68g (n = 10, weight average molecular weight (Mw): 3,000 g / mol) which was added to 0.3g and the polymerization initiator, 0.02g and a secondary battery was prepared comprising the same manner as in example 1, a gel polymer electrolyte composition and a gel polymer electrolyte using the same for a negative one.
[225]
[226]
Example 8.
[227]
When the composition prepared for the gel polymer electrolyte, non-aqueous compound of formula 1a-1 wherein the organic solvent 70g (n = 10, weight average molecular weight (Mw): 3,000 g / mol), except that the addition of 25g and a polymerization initiator 5g It was prepared in a secondary battery comprising the above example 1, by a method similar to the composition for gel polymer electrolytes, and gel polymer electrolyte using the same.
[228]
[229]
Example 9.
[230]
When the gel polymer electrolyte composition prepared for a non-aqueous compound of formula 1a-1 wherein the organic solvent 94.8g: the addition of a (n = 10, weight average molecular weight (Mw) 500 g / mol) 5g and a polymerization initiator 0.2g except for a secondary battery was prepared comprising the above example 1, by a method similar to the composition for gel polymer electrolytes, and gel polymer electrolyte using the same.
[231]
[232]
Example 10.
[233]
When the gel polymer electrolyte composition prepared for a non-aqueous organic solvent a compound of formula 1a-1 to the 94.8g (n = 10, weight average molecular weight (Mw): 20,000 g / mol) to the addition of 5g and a polymerization initiator 0.2g except for a secondary battery was prepared comprising the above example 1, by a method similar to the composition for gel polymer electrolytes, and gel polymer electrolyte using the same.
[234]
[235]
Comparative Example 1.
[236]
(The non-aqueous electrolyte, Ltd.)
[237]
1M LiPF 6 the non-aqueous organic solvent to prepare a non-aqueous electrolyte solution by dissolving the (ethylene carbonate (EC): 7 volume ratio: ethyl methyl carbonate (EMC) = 3).
[238]
[239]
(Preparation of lithium secondary battery)
[240]
As a cathode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 ; NCM) 94% by weight, of a conductive material of carbon black (carbon black) 3% by weight of polyvinyl a binder fluoride (PVDF) 3 parts by weight % were added to N- methyl-2-pyrrolidone (NMP) solvent producing a positive electrode active material slurry (solid content 50%). After the positive electrode active material slurry is applied to a thickness approximately the positive electrode collector of aluminum (Al) film of 20㎛ and dried to produce a positive electrode, a positive electrode subjected to a roll press (press roll) was prepared.
[241]
A carbon powder, a binder, a negative electrode active material to PVDF, the conductive material of carbon black (carbon black), respectively 96 wt%, 3 wt% to 1 wt% was added to the solvent NMP negative electrode active material slurry (solid content 80%) It was prepared. After the above is a negative electrode active material slurry was applied to a thickness of the anode current collector, copper (Cu) thin film of 10㎛ and dried to produce a negative electrode, a negative electrode subjected to a roll press (press roll) was prepared.
[242]
By laminating the positive electrode, a negative electrode and a polypropylene / polyethylene / polypropylene (PP / PE / PP) separator consisting of three layers, in order to prepare an electrode assembly.
[243]
The positive electrode, negative electrode and a polypropylene / polyethylene / polypropylene (PP / PE / PP) produced an electrode assembly with a separator consisting of three layers, and, by accommodating them in a battery case and injecting the non-aqueous electrolyte thus prepared lithium secondary battery, It was prepared (Full cell).
[244]
[245]
Comparative Example 2.
[246]
(Gel polymer electrolyte composition prepared for)
[247]
1M LiPF 6 is dissolved non-aqueous organic solvent (ethylene carbonate (EC): ethyl methyl carbonate (EMC) = 3: 7 volume ratio) to the 95g ETPTA (ethoxylated tri-methylolpropane triacrylate) represented by the formula (3) oligomers 5g and a polymerization initiator as dimethyl 2,2'-azobis (2-methylpropionate) (CAS No. 2589-57-3) was added to 0.2g were prepared for gel polymer electrolyte composition.
[248]
[Formula 3]
[249]
[250]
[251]
(Preparation of lithium secondary battery)
[252]
Except for using the above prepared for gel polymer electrolyte composition was prepared in a rechargeable lithium battery including the gel polymer electrolyte by the same method as in Example 1.
[253]
[254]
To summarized the construction of Examples 1 to 10 compared for gel polymer electrolyte composition of Example 1 and for the composition of the second gel polymer compositions are shown in Table 1.
[255]
TABLE 1
[256]
[257]
Experimental Example
[258]
Experimental Example 1: High-temperature Stability evaluation (1)
[259]
Examples 1 and 2 of the gel polymer electrolyte secondary battery, and comparing the secondary battery, and Comparative Example 2 of the gel polymer electrolyte having a high-temperature storage to the secondary battery each at the SOC 100% state, including containing a non-aqueous electrolyte solution of Example 1 containing (60 ℃) which was then measured for the thickness increase rate (%). The results are shown in Fig.
[260]
Looking at the thickness increase rate (%) of Figure 1, in the case of Example 1 and the secondary battery 2 using for the gel polymer electrolyte composition comprising the oligomer according to the present invention, compared with the non-aqueous electrolytic solution that does not contain the oligomer example 1 compared to a secondary battery and a secondary battery of Comparative example 2 using the composition for gel polymer electrolyte can be confirmed that the thickness increase rate at a significantly reduced from 60 ℃ after 4 weeks.
[261]
[262]
Experimental Example 2: High-temperature Stability Evaluation 2
[263]
Subjected to a lithium secondary battery prepared in Examples 3-10 was charged with 0.1C rate 3 hours. Then, the degassing (degas) / resealed (reseal), and is charged by constant current / constant voltage condition by 0.2C at room temperature for up to 4.15V with 0.2C to 3.0V with a constant current discharge conditions to perform the initial charging and discharging. After the initial charging and discharging, respectively, and charged to 4.15V, 60 ℃ 6 in the main reservoir (SOC (state of charge), 100%) of capacity retention rate, compared to 6 weeks 0 parked car with the cell (%), and thickness change ratio for (swelling ) it was measured.
[264]
The results are shown in Table 2.
[265]
TABLE 2
[266]
[267]
The As shown in Table 2, and Examples 3 to 6, a lithium secondary battery manufactured by the high-temperature storage capacity retention rate after at least about 94%, after high-temperature storage can be seen that the thickness increase is greater than about 7.5%.
[268]
On the other hand, the lithium secondary battery of Example 7 having a small amount of oligomer is included for the gel polymer electrolyte composition is the performance test were not upset hard gel.
[269]
Further, in the oligomer is provided with a gel polymer electrolyte containing an excess For exemplary lithium secondary battery 8 is a resistance increase the high temperature storage after the capacity retention ratio is more than 90.1% because of the in the electrolyte, after high-temperature storage thickness growth by 15.9% Example 3 a lithium secondary battery manufactured to 6 it can be seen that the contrast deteriorates.
[270]
The weight average molecular weight is carried out provided with a gel polymer electrolyte containing a low oligomers example after high temperature storage of the lithium secondary battery, the capacity maintenance rate of 9 is more than 91%, after high-temperature storage thickness growth gel polymer in the same condition as 10.8% causing a reaction in the reaction disadvantage, embodiments can be seen that the deteriorated lithium secondary battery prepared in example 3 compared to 6.
[271]
In addition, the weight of the lithium secondary battery of Example 10, the average molecular weight is provided with a gel polymer electrolyte containing a high oligomer is a gel polymer electrolyte composition, since the wetting effect decreases with increasing viscosity, exemplary lithium prepared in Examples 3 to 6 it can be seen that the deterioration of contrast secondary battery.
Claims
[Claim 1]
A lithium salt; The non-aqueous organic solvent; To the oligomer represented by formula (1); A gel polymer electrolyte composition comprises; and a polymerization initiator. Formula 1 In Formula 1, R 1 to R 3 each independently are substituted or unsubstituted alkylene group of 1 to 4 carbon atoms ring with fluorine, R 4 and R 5 is an aliphatic hydrocarbon, each independently, or an aromatic hydrocarbon group and, R 6 and R 7 are each independently an alkyl group or a group having 1 to 10 carbon atoms , and wherein R 8 and R 9 is an alkyl group or a group having 1 to 10 carbon atoms independently , and wherein R 10 is an aliphatic hydrocarbon group or aromatic hydrocarbon group and, R 11 is an alkylene group of a carbon number of 1 to 3, R 12 is hydrogen or an alkyl group having 1 to 2, n is between 1 and 70 any integer of, m is any integer of 1 to 3 .
[Claim 2]
The method according to claim 1, in the oligomer of the formula (1), the aliphatic hydrocarbon group is a cycloalkylene group of the substituted or unsubstituted 4 to 20 carbon atoms; Isocyanate group-cycloalkylene group of substituted or unsubstituted 4 to 20 carbon atoms containing a (NCO); Cycloalkenyl group substituted or unsubstituted 4 to 20 carbon atoms; And a substituted or unsubstituted C2 to heterocycloalkyl or more of at least one selected from the group consisting of alkylene groups of 20 alicyclic hydrocarbon group, or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Isocyanate group-containing substituted (NCO) or unsubstituted alkylene group having 1 to 20 carbon atoms; Xylene alkoxyl group of substituted or unsubstituted C1 to C20; Substituted or unsubstituted alkenylene group of 2 to 20 carbon atoms; And a substituted or unsubstituted carbon atoms, and at least one linear hydrocarbon group selected from 2 to 20 alkynylene group group consisting of the aromatic hydrocarbon group is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or a substituted or unsubstituted heteroarylene group that a gel polymer electrolyte composition of 2 to 20 carbon atoms.
[Claim 3]
The method according to claim 1, wherein the composition for gel polymer electrolyte to an oligomer of the formula (1) comprises an oligomer represented by the following formula 1a: [Chemical Formula 1a] in the formula 1a, R 4 and R 5 is an aliphatic, each independently hydrocarbon group, R 8 and R 9 are each independently a, R 10 is an aliphatic hydrocarbon group, R 11 is an alkylene group of a carbon number of 1 to 3, R 12 is hydrogen or an alkyl group having 1 to 2, n is is any integer of from 10 to 20, m is any integer of 1 to 2.
[Claim 4]
The method according to claim 3, the oligomer represented by the formula (1a) is to a composition for a gel polymer electrolyte comprising an oligomer of the formula 1a-1: [Chemical Formula 1a-1] in the formula 1a-1, n is from 10 to which it is the integer of 20.
[Claim 5]
The method according to claim 1, the oligomer of the formula (1) is a gel polymer electrolyte composition is included at 0.5% to 20% by weight, based on the total weight for the gel polymer electrolyte composition.
[Claim 6]
The method according to claim 5, the oligomer of the formula (1) is a gel polymer electrolyte composition is included at 0.5% to 10% by weight, based on the total weight for the gel polymer electrolyte composition.
[Claim 7]
The method according to claim 1, and a weight average molecular weight (MW) of the oligomer represented by the formula (1) is 1,000 g / mol to about 10,000 g / mol in that a gel polymer electrolyte composition.
[Claim 8]
The system according to claim 7, and a weight average molecular weight (MW) of the oligomer represented by the formula (1) is 3,000 g / mol to about 8,000 g / mol in that a gel polymer electrolyte composition.
[Claim 9]
The method according to claim 8, and a weight average molecular weight (MW) of the oligomer represented by the formula (1) is 3,000 g / mol to about 5,000 g / mol in that a gel polymer electrolyte composition.
[Claim 10]
After injecting the cells for the gel polymer electrolyte composition of claim 1 under an inert atmosphere, a gel polymer electrolyte being formed by polymerization.
[Claim 11]
A negative electrode, a positive electrode, a lithium secondary battery comprises a separator, and a gel polymer electrolyte according to Claim 10 disposed between the cathode and the anode.