KR102691507B1 - Monomer compound for solid polymer electrolyte, electrolyte composition including the same compound, solid polymer electrolyte formed from the same composition, and lithium secondary battery compsiring the same electrolyte - Google Patents

Abstract

The present invention relates to a composition for a solid polymer electrolyte, a solid polymer electrolyte formed therefrom, and a lithium secondary battery containing the same. Specifically, the mobility and conductivity of ions including lithium ions in the electrolyte are improved, and it is electrochemically stable. This excellent composition for a solid polymer electrolyte, a solid polymer electrolyte formed therefrom, and a lithium secondary battery including the same have improved output characteristics at low temperatures and have excellent electrochemical stability and safety.

Description

Monomer compounds for solid polymer electrolytes, solid polymer electrolyte compositions containing the same, solid polymer electrolytes formed therefrom, and lithium secondary batteries containing the same COMPOSITION, AND LITHIUM SECONDARY BATTERY COMPSIRING THE SAME ELECTROLYTE}

The present invention relates to a monomer compound for a solid polymer electrolyte, a solid polymer electrolyte composition containing the same, a solid polymer electrolyte formed therefrom, and a lithium secondary battery containing the same. Specifically, the mobility of ions including lithium ions in the electrolyte is improved. Provides a monomer compound for a solid polymer electrolyte with excellent electrochemical stability, a composition containing the same, a solid polymer electrolyte formed therefrom, and a lithium secondary battery including the same with improved output characteristics at low temperatures and excellent electrochemical stability and safety. do.

Various methods are being explored to increase the energy density of lithium-ion batteries, and one of them is the use of lithium metal in the cathode. However, lithium ion batteries using lithium metal negative electrodes have a problem in which battery performance is significantly reduced due to the lithium dendrite phenomenon that occurs during charging/discharging. In addition, existing lithium-ion batteries have a problem with low battery stability due to the use of flammable liquid electrolytes. To improve this, research is being actively conducted on the development of solid-state batteries using solid electrolytes with high ionic conductivity and high electrochemical stability.

In general, in all-solid-state batteries, linear polymers or cross-linked polymers of homopolymer or copolymer with ethylene oxide as the basic unit are mainly used as ion conductive polymers for forming solid electrolytes, but these polymers are not crystallized. There is a problem that the output characteristics and electrochemical characteristics of the all-solid-state battery are reduced due to low ionic conductivity at low temperatures.

Therefore, there is a need for the development of a solid electrolyte with improved output characteristics at low temperatures and excellent ionic conductivity.

KR 10-2018-0116145 (2018.10.24.)

The present invention was developed to solve the above-mentioned problems, and the first problem to be solved by the present invention is to provide a monomer compound for a solid polymer electrolyte with improved mobility of lithium ions, improved ionic conductivity, and excellent electrochemical stability. , a composition containing the same and a solid polymer electrolyte formed therefrom are provided.

The second problem to be solved by the present invention is to provide a lithium secondary battery with excellent output characteristics at low temperatures and excellent electrochemical stability and safety by introducing the above-mentioned solid polymer electrolyte.

In order to solve the first problem described above, the present invention provides a monomer compound for a polymer electrolyte represented by the following formula (1).

[Formula 1]

A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ hetero One or two or more selected from arylene groups are combined,

A ¹¹ is a combination of one or two or more selected from C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ heteroarylene group. ,

The A ¹¹ is substituted with one or more hydroxyl groups,

R ¹⁰ is each independently hydrogen, an alkyl group of C ₁ to C ₆ , a haloalkyl group of C ₁ to C ₆ , a heteroalkyl group of C ₁ to C ₆ , a cycloalkyl group of C ₅ to C ₁₀ , and an aryl group of C ₆ to C ₁₄ group or one selected from C ₃ to C ₁₄ heteroaryl group,

R ¹¹ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group,

R ¹² is an alkylene group of C ₂ to C ₉ , and n10 is an integer of 0 to 10.

In a preferred embodiment of the present invention, the monomer compound for solid polymer electrolyte may be represented by the following formula 1-1.

[Formula 1-1]

In Formula 1-1,

A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ hetero One or two or more selected from arylene groups are combined,

R ¹⁰ is each independently hydrogen, an alkyl group of C ₁ to C ₆ , a haloalkyl group of C ₁ to C ₆ , a heteroalkyl group of C ₁ to C ₆ , a cycloalkyl group of C ₅ to C ₁₀ , and an aryl group of C ₆ to C ₁₄ group or one selected from C3 to C14 heteroaryl group,

R ¹¹ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group,

R ¹² is an alkylene group of C ₂ to C ₁₀ , and n10 is an integer of 0 to 10.

In a preferred embodiment of the present invention, the compound may be a compound represented by the following formula 1-2.

[Formula 1-2]

In Formula 1-2,

A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ heteroaryl It is a combination of one or two or more selected from Rengi,

R ¹² is an alkylene group of C ₂ to C ₉

R ¹³ is hydrogen or a methyl group, and n10 is an integer from 0 to 10.

In a preferred embodiment of the present invention, the compound has the following formula:

It may be a compound represented by 1-3.

[Formula 1-3]

In Formula 1-3,

R ¹³ is hydrogen or a methyl group, and n10 is an integer from 0 to 10.

The present invention also provides a first monomer consisting of the above monomer compound for polymer electrolyte; A second monomer having two or more ethylenically unsaturated functional groups and capable of forming a crosslinked structure; and a lithium salt. It provides a solid polymer electrolyte composition comprising a.

In a preferred embodiment of the present invention, the ethylenically unsaturated functional group of the second monomer may be a vinyl group or an acryloyl group.

In a preferred embodiment of the present invention, the second monomer may include at least one of the compounds represented by the following formulas 2-1 to 2-3.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

In Formulas 2-1 to 2-3,

R ²⁰ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group,

R ²¹ is each independently a C ₁ to C ₁₀ alkylene group, a C ₅ to C ₁₄ cycloalkylene group, a C ₆ to C ₁₄ arylene group, a C ₃ to C ₁₃ heteroarylene group, or a C ₁ to C ₁₀ It is a haloalkylene group, and R ²² is each independently -(O ^* CH ₂ CH ₂ )(OCH ₂ CH ₂ ) _a1 -, -(O ^* CH ₂ CH(CH ₃ ))(OCH ₂ CH(CH ₃ )) _a2 - or -(O ^* CH ₂ CH ₂ )(OCH ₂ CH ₂ ) _a1 (OCH ₂ CH(CH ₃ )) _a3 -, where the oxygen (O ^* ) marked with * is bonded to R ²¹ ,

The a1 and a2 are each independently an integer from 0 to 10, and a3 is an integer from 1 to 10.

In a preferred embodiment of the present invention, the second monomer may be a compound represented by the following formula 2-4.

[Formula 2-4]

In Formula 2-4, b is each independently an integer of 1 to 5.

In a preferred embodiment of the present invention, the second monomer may be a compound represented by the following formula (3).

[Formula 3]

In Formula 3 above,

R ³⁰ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group.

In a preferred embodiment of the present invention, the solid polymer electrolyte composition may contain 3 to 60% by weight of the first monomer and 5 to 50% by weight of the second monomer.

In a preferred embodiment of the present invention, the lithium salt contains Li + as a cation, and F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , N(CN) ₂ ^- , ClO ₄ ^- , BF 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 ^- , (FSO ₂ ) ₂ N ^- , CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , (SF ₅ ) ₃ C ^- , (CF ₃ SO ₂ ) ₃ C ^- , 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 ^- It may include at least one selected from the group.

In a preferred embodiment of the present invention, the content of lithium salt in the solid polymer electrolyte composition may be 10 to 40% by weight of the total composition.

In a preferred embodiment of the present invention, the solid polymer electrolyte composition may further include a plasticizer and an initiator.

In a preferred embodiment of the present invention, the plasticizer is succinonitrile, glutaronitrile, polyethylene glycol dimethylether, tetraethylene glycol, and ethylene carbonate. ), propylene carbonate, tetraethylene glycol dimethylether (tetraglyme), dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate (dioctyl phthalate), cyclic phosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide], 1 -Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide], N-methyl-N-propylpiperidinium bis(trifluoromethane Sulfonyl)imide [N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide], 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, N-butyl -N-ethylpyrrolidinium bis(trifluoromethanesulfonyl)imide [N-butyl-Nethylpyrrolidinium bis(trifluoromethanesulfonyl)imide] may be included.

Additionally, the present invention provides a solid polymer electrolyte formed by curing the solid polymer electrolyte composition.

In a preferred embodiment of the present invention, the solid polymer electrolyte may include a polymer having a three-dimensional network structure in which the first monomer and the second monomer are polymerized and cross-linked to each other.

In order to solve the second problem described above, the present invention provides an anode; cathode; and a lithium secondary battery including the solid polymer electrolyte.

The solid polymer electrolyte according to the present invention suppresses crystallization, improves the mobility of lithium ions, improves ion conductivity, and has excellent electrochemical stability, which can contribute to improving the stability and output of lithium secondary batteries.

The lithium secondary battery according to the present invention has excellent output characteristics at low temperatures and excellent electrochemical stability and safety, making it suitable for use in electric vehicles.

Figure 1 is a diagram showing a representative Nyquist plot measuring the impedance of a 2032 coin cell for measuring ionic conductivity manufactured according to Example 1.
Figure 2 is an LSV graph of a coin cell for measuring electrochemical stability manufactured according to Example 1.

Before describing the present invention in more detail, the meaning of terms used in this specification will be defined.

In this specification, “polyfunctional” refers to the characteristic of having two or more functional groups that participate in a reaction, and “multifunctional monomer” refers to a branched polymer or cross-linked polymer with two or more functional groups that can participate in a polymerization reaction. It means a monomer that can be formed.

In this specification, unless otherwise stated, the fact that a substituent is “substituted or unsubstituted” means that the substituent includes both cases where the substituent is substituted by a functional group to be described later and cases where the substituent is not substituted. Here, the functional group in case of substitution is, for example, alkyl, acyl, cycloalkyl (including dicycloalkyl and tricycloalkyl), haloalkyl, aryl ( aryl), heteroaryl, heteroalicyclic, hydroxy, alkoxy, azide, amine, ketone, ether, amide (amide), ester, triazole, isocyanate, arylalkyloxy, aryloxy, mercapto, alkylthio, arylthio , cyano, halogen, carbonyl, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl (O-thiocarbamyl), N-thiocarbamyl, C-amido (C-amido), N-amido (N-amido), S-sulfonamido (Ssulfonamido), N-sulfonami N-sulfonamido, C-carboxy, O-carboxy, isocyanate, thiocyanate, isothiocyanate, nitro , silyl, trihalomethane sulfonyl, pyrrolidinone, pyrrolidine, piperidine, piperazine, morpholine, aldehyde, phosphorus, sulfur, phosphate, phosphite, sulfate, disulfide, oxy; and aminos containing hydrocarbylmono- and di-(hydrocarbyldi-) substituted amino groups, and derivatives thereof, but are not limited thereto and include various functional groups commonly used in the art. do. Also, substituted means that the functional group is bonded to at least one carbon of the substituent.

In this specification, “ethylenically unsaturated functional group” refers to the structure of a C=C double bond, and the pi bond in the double bond can be broken to cause a polymerization reaction.

In this specification, “acryloyl group” includes a substituted or unsubstituted acryloyl group, preferably It means having a structure of. The R represents hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group.

As used herein, “alkyl group” refers to a monovalent aliphatic hydrocarbon group. The alkyl groups include linear (unbranched) and branched (branched). Alkyl groups include, for example, methyl, ethyl, propyl, isopropyl, n-butyl, n-pentyl, and n-hexyl. It may be one or more selected from the group consisting of (n-hexyl), but is not necessarily limited thereto.

As used herein, “cycloalkyl group” refers to a monovalent aliphatic cyclic hydrocarbon group. The cycloalkyl group is, for example, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. It is selected from the group consisting of (cyclodecyl). However, it is not necessarily limited to this.

Additionally, in this specification, “alkylene group” refers to a divalent aliphatic hydrocarbon group. The alkylene group represents, for example, one selected from methylene, ethylene, propylene, butylene, pentylene, and hexylene. However, it is not necessarily limited to this.

As used herein, “cycloalkylene group” refers to a divalent aliphatic cyclic hydrocarbon group. The positional relationship of the bivalent bond arm is not mattered. For example, it may be selected from the group consisting of 1,2-cycloalkylene group, 1,3-cycloalkylene group, 1,4-cycloalkylene group, and 1,5-cycloalkylene group. The cycloalkylene group is, for example, 1,2-cyclobutylene, 1,3-cyclobutylene, and 1,2-cyclopentylene. , 1,3-cyclopentylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1, 4-cyclohexylene, 1,2-cycloheptylene, 1,3-cycloheptylene, 1,4-cycloheptyl Len group (1,4-cyclohelptylene), 1,2-cyclooctylene group (1,2-cyclooctylene), 1,3-cyclooctylene group (1,3-cyclooctylene), 1,4-cyclooctylene group (1,4 -cyclooctylene), and 1,5-cyclooctylene (1,5-cyclooctylene), but is not limited thereto.

As used herein, “heteroalkyl group” means that one or more carbon atoms in the carbon chain of the alkyl group are replaced with a hetero atom.

As used herein, “heteroalkylene group” means that one or more carbon atoms in the carbon chain of an alkylene group are substituted with a heteroatom.

In addition, the heteroalkylene group of C _a to C _b refers to a heteroalkylene group having a to b carbon atoms among heteroalkylene groups.

As used herein, “heteroatom” means an atom other than carbon and hydrogen.

In this specification, an "aryl group" is an aromatic substituent having a univalent shared π electron system, and includes a monocyclic or polycyclic group of two or more rings, and a ring This means that all elements are made of carbon. Aryl groups include both substituted and unsubstituted groups.

Examples of aryl groups include , , , , , and However, it is not necessarily limited to this.

In this specification, “arylene group” refers to a divalent aromatic substituent that has one additional bonding arm in the aryl group.

In this specification, “heteroaryl group” means an aromatic substituent having a univalent shared pi electron system, and at least one of the atoms forming the ring is a heteroatom.

Examples of heteroaryl groups include , , , , , , , , , , , , , , , , , , , , , , , and There is.

Here, R ^m is H, a C ₁ -C ₂₀ alkyl group, or a C ₃ -C ₁₄ heteroaryl group.

Additionally, in this specification, a “heteroarylene group” refers to an aromatic substituent having a divalent shared pi electronic system, and represents a form in which the heteroarylene group has one more bonding arm.

As used herein, “haloalkyl group” specifically refers to an alkyl group in which one or more hydrogens are replaced with halogen (F, Cl, Br, I) atoms. Additionally, the haloalkyl group of C _a to C _b refers to a haloalkyl group having a to b carbon atoms. “Haloalkylene group” means an alkylene group in which one or more hydrogens have been replaced with a halogen atom.

Additionally, in this specification, “haloalkylene group” specifically means an alkylene group in which one or more hydrogens are replaced with a halogen atom. In addition, the haloalkylene group of C _a to C _b refers to a haloalkylene group having a to b carbon atoms.

Additionally, in this specification, “amide group” refers to a -C(O)NH- bond, and the hydrogen bonded to nitrogen in the amide bond may be substituted or unsubstituted.

In addition, in this specification, “no substituent exists” means a form in which both atoms are directly bonded without the corresponding substituent. For example, when substituent A is not present in a molecule of the form CH ₃ -A-CH ₃ , the chemical formula of the molecule is CH ₃ -CH ₃ .

Hereinafter, the present invention will be described in more detail.

The present inventors accelerated research to solve the problem of poor output of secondary batteries, such as a significant decrease in ionic conductivity at low temperatures due to crystallization of solid polymer electrolytes in conventional all-solid-state secondary batteries, and came up with the present invention. It came down to this.

First, the solid polymer electrolyte composition of the present invention will be described.

(1) Solid polymer electrolyte composition

The present invention provides a solid polymer electrolyte composition to solve the above-mentioned problems, including a first monomer, a second monomer, and a lithium salt. The first monomer is a polyfunctional monomer containing a urethane bond and two or more ethylenically unsaturated functional groups, and the second monomer contains two or more ethylenically unsaturated bonds to enable crosslinking between the first monomer or the second monomer. It is a multifunctional monomer.

By using the polymer electrolyte composition containing the first monomer, the present invention can further suppress crystallization of the solid polymer electrolyte and implement a solid polymer electrolyte with improved mobility and conductivity of ions including lithium in the electrolyte even at low temperatures.

In addition, because a hydroxy group is present in the side chain, the solid electrolyte produced from the polymer as the monomer of the present invention has good adhesion at the interface between the anode and the cathode, which has the effect of lowering the interfacial resistance between the electrode and the solid electrolyte.

1) First monomer

The first monomer included in the solid polymer electrolyte composition according to the present invention is a polyfunctional monomer compound containing a urethane bond and two or more ethylenically unsaturated functional groups, as represented by the following formula (1).

[Formula 1]

The solid polymer electrolyte formed from the above composition can have excellent lithium ion mobility and ion conductivity by significantly suppressing crystallization at low temperatures compared to conventional polyethylene oxide-based polymer electrolytes, thereby significantly improving the low-temperature output characteristics of lithium secondary batteries. There is an advantage to being able to do it. In particular, the solid polymer electrolyte has the effect of preventing the formation of ion pairs with anions through coordination of the urethane bond contained in the polymerized monomer with lithium ions, thereby improving the solubility of lithium ions. In addition, since it contains two polymerizable ethylenically unsaturated functional groups, crosslinking is possible during polymerization to form a polymer with a three-dimensional network structure, which has the effect of imparting mechanical properties. In particular, since not only the second monomer, which is a crosslinkable multifunctional monomer, but also the first monomer is composed of a crosslinkable polyfunctional monomer, not only excellent electrical properties but also excellent mechanical properties (tensile strength and shear strength) can be achieved.

R ¹⁰ is each independently selected from hydrogen, an alkyl group, a haloalkyl group, a heteroalkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group.

Preferably, R ¹⁰ is each independently hydrogen, C ₁ to C ₆ alkyl group, C ₁ to C ₆ haloalkyl group, C ₁ to C ₆ heteroalkyl group, C ₅ to C ₁₀ cycloalkyl group, C ₆ to C It may be one selected from an aryl group of ₁₄ or a heteroaryl group of C ₃ to C ₁₄ .

R ¹¹ is each independently hydrogen, an alkyl group, a haloalkyl group, or a heteroalkyl group. Preferably, R ¹¹ may each independently be hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group.

A ¹⁰ has one or more structures selected from the group consisting of an alkylene group, a cycloalkylene group, an arylene group, a heteroarylene group, and a polyalkylene oxide structure. It is a bonded connector.

Preferably, A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ to C ₁₀ alkylene group, C ₅ to C ₁₄ cycloalkylene group, C ₆ to C ₁₄ arylene group, C ₃ to C ₁₄ It may be a linking group in which one or two or more selected from heteroarylene groups are combined.

Here, R ¹² is an alkylene group of C ₂ to C ₉ , and n10 is an integer of 0 to 10.

A ¹¹ is a divalent linking group substituted with one or more hydroxyl groups.

Preferably, a linkage of one or two or more selected from C ₂ to C ₉ alkylene group, C ₅ to C ₁₄ cycloalkylene group, C ₆ to C ₁₄ arylene group, and C ₃ to C ₁₄ heteroarylene group. It could be a sign.

When A ¹¹ is one of the above substituents, the substituent is substituted with one hydroxy group, and when A ¹¹ is a combination of two or more of the above substituents, at least one of the substituents is substituted with a hydroxy group.

More preferably, A ¹¹ is an ethylene group substituted with one hydroxy group, that is, It can be.

In this case, the monomer compound for solid polymer electrolyte is a compound represented by the following formula 1-1.

[Formula 1-1]

In Formula 1-1,

A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ hetero One or two or more selected from arylene groups are combined,

R ¹⁰ is each independently hydrogen, an alkyl group of C ₁ to C ₆ , a haloalkyl group of C ₁ to C ₆ , a heteroalkyl group of C ₁ to C ₆ , a cycloalkyl group of C ₅ to C ₁₀ , and an aryl group of C ₆ to C ₁₄ group or one selected from C ₃ to C ₁₄ heteroaryl group,

R ¹¹ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group,

R ¹² is an alkylene group of C ₂ to C ₁₀ , and n10 is an integer of 0 to 10.

Additionally, in Formula 1-1, R ¹⁰ may be hydrogen. In this case, the first monomer may be a compound represented by the following formula 1-2.

[Formula 1-2]

In Formula 1-2,

A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ heteroaryl It is a linking group in which one or two or more selected from the ren groups are bonded,

Here, R ¹² is an alkylene group of C ₂ to C ₁₀ , and n10 is an integer of 0 to 10.

Additionally, R ¹³ is hydrogen or a methyl group.

Preferably, A ¹⁰ may be preferably -CH ₂ CH ₂ (OCH ₂ CH ₂ ) _n10 -, where n10 is an integer from 0 to 10.

In this case, the first monomer is a compound represented by the following formula 1-3.

[Formula 1-3]

In Formula 1-3,

R ¹³ is hydrogen or a methyl group, and n10 is an integer from 0 to 10.

The polymer electrolyte composition according to the present invention may include the first monomer in an amount of 3 to 60% by weight. Preferably, the content of the first monomer may be 5 to 30% by weight. If the content of the first monomer is less than 3% by weight, there may be a disadvantage of not showing the advantages of the first monomer. Conversely, if the content of the first monomer is more than 60% by weight, the crosslinking density increases, lowering processability, and relatively lithium in the polymer solid electrolyte. There may be a problem of low ionic conductivity at room temperature due to salt and plasticizer being present in a low ratio.

2) second monomer

In addition to the first monomer containing the urethane bond, the present invention has two or more ethylenically unsaturated functional groups, and thus can cause a crosslinking reaction between the first monomer or the second monomer to form a three-dimensional network structure. It may further include a polyfunctional second monomer.

The second monomer has two or more ethylenically unsaturated functional groups, so that upon curing, polymerization may occur at two or more points, thereby allowing a crosslinking reaction to occur, thereby forming a three-dimensional network structure, thereby forming a polymer having excellent mechanical properties. It makes it possible to implement a solid polymer electrolyte for solid batteries.

Here, the ethylenically unsaturated functional group may preferably have a vinyl group or acryloyl group structure. Containing two or more ethylenically unsaturated functional groups includes not only containing two or more vinyl groups or two or more acryloyl groups, but also including two or more vinyl groups and acryloyl groups together.

The second monomer may preferably be a multifunctional acrylate-based monomer containing two or more acryloyl groups.

The second monomer may preferably include at least one of the compounds represented by the following formulas 2-1 to 2-3.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

In Formulas 2-1 to 2-3,

R ²⁰ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group,

R ²¹ is each independently a C ₁ to C ₁₀ alkylene group, a C ₅ to C ₁₄ cycloalkylene group, a C ₆ to C ₁₄ arylene group, a C ₃ to C ₁₃ heteroarylene group, or a C ₁ to C ₁₀ It is a haloalkylene group, and R ²² is each independently -(O ^* CH ₂ CH ₂ )(OCH ₂ CH ₂ ) _a1 -, -(O ^* CH ₂ CH(CH ₃ ))(OCH ₂ CH(CH ₃ )) _a2 - or -(O ^* CH ₂ CH ₂ )(OCH ₂ CH ₂ ) _a1 (OCH ₂ CH(CH ₃ )) _a3 -, where the oxygen (O ^* ) indicated by * is bonded to R ²¹ ,

a1 and a2 are each independently integers from 0 to 10, and a3 is an integer from 1 to 10.

Preferably, the second monomer may be a compound represented by the following formula 2-4.

[Formula 2-4]

In Formula 2-4, b is each independently an integer of 1 to 5.

Also, preferably, the second monomer may be a compound represented by the following formula 2-4-1.

[Formula 2-4-1]

In addition, in a preferred embodiment of the present invention, the second monomer may be a compound represented by the following chemical formula 3.

[Formula 3]

In Formula 3 above,

R ³⁰ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group.

Additionally, as described above, the acryloyl groups may each independently be substituted or unsubstituted, and for example, may be a methacryloyl group substituted with a methyl group.

The second monomer may preferably be included in an amount of 5 to 50% by weight based on the total composition. More preferably, it may be included in an amount of 10 to 30% by weight.

If the content of the second monomer exceeds 50% by weight, the crosslinking density may increase and the ionic conductivity at room temperature may decrease. Additionally, if the content of the second monomer is less than 5% by weight, the effect of adding the second monomer is hardly visible.

In addition, the sum of the contents of the first monomer and the second monomer may be 10 to 70% by weight, preferably 15 to 60% by weight, relative to the solid polymer electrolyte composition.

If the total content of the monomer is less than 10% by weight of the total composition, even if curing is performed, the content of the polymer constituting the polymer matrix is relatively reduced, so there may be a problem in which the solid polymer electrolyte membrane is not properly formed. If it exceeds this, there may be a problem in which the ionic conductivity of the electrolyte decreases due to the relatively low content of lithium salt and plasticizer.

3) Lithium salt

The lithium salt is used as an electrolyte salt in a lithium all-solid secondary battery, and is used as a medium to transfer ions. Typically, lithium salts include lithium cations (Li ⁺ ), F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , N(CN) ₂ ^- , ClO ₄ ^- , BF 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 ^- , (FSO ₂ ) ₂ N ^- , CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , (SF ₅ ) ₃ C ^- , (CF ₃ SO ₂ ) ₃ C ^- , 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 ^- at least one anion selected from the group consisting of It may include

The lithium salt may be appropriately modified within the range commonly available, but may be included in a content of 10 to 40% by weight in the solid polymer electrolyte composition in order to obtain the optimal effect of forming an anti-corrosion film on the electrode surface.

The solid polymer electrolyte composition of the present invention includes a lithium salt in the content within the above range, resulting in high lithium cation (Li ⁺ ) ion transport characteristics (i.e., cation transport rate ( transference number)) can be secured, and the effect of reducing the diffusion resistance of lithium ions can be achieved to improve cycle capacity characteristics. At this time, when the lithium salt content is less than 10% by weight, it is difficult to secure sufficient ionic conductivity of lithium ions due to the relatively low lithium ion content. In addition, if the concentration of the lithium salt exceeds 40% by weight, the lithium salt is not solvated in the polymer matrix and a large amount of lithium salt forming an ion-pair exists, so there is no significant increase in effectiveness and it is economical. Since it is disadvantageous, it is desirable to appropriately adjust it to suit the purpose within the above content range.

4) Plasticizer

The solid polymer electrolyte composition according to the present invention may further include a plasticizer.

Plasticizers serve to facilitate the transfer of lithium ions at low temperatures by lowering the crystallinity between polymer chains forming a solid polymer electrolyte, improve the processability of the solid polymer electrolyte, and make it easier to control mechanical strength.

The plasticizer is preferably succinonitrile, glutaronitrile, polyethylene glycol dimethylether, tetraethylene glycol, ethylene carbonate, and propylene carbonate. ), tetraethylene glycol dimethylether (tetraglyme), dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, cyclic Phosphate (cyclic phosphate), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide], 1-butyl-3-methyl Midazolium bis(trifluoromethanesulfonyl)imide [1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide], N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide[N -methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide], 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, N-butyl-N-ethylpyrrolidinium It may include one or more selected from bis(trifluoromethanesulfonyl)imide [N-butyl-Nethylpyrrolidinium bis(trifluoromethanesulfonyl)imide], but is not necessarily limited thereto.

The content of the plasticizer may be 10 to 70% by weight of the total solid polymer electrolyte composition. If the content of the plasticizer is less than 10% by weight, the crystallinity of the solid polymer electrolyte may increase at low temperatures, which may cause a problem of lowering ionic conductivity. If it exceeds 70% by weight, the mechanical properties of the solid polymer electrolyte may deteriorate. There may be a problem.

The content of the plasticizer may preferably be 15 to 65% by weight.

5) Initiator

Additionally, the solid polymer electrolyte composition according to the present invention can form a solid polymer electrolyte through a crosslinking reaction of monomers. As polymerization and crosslinking reactions occur, the solid polymer electrolyte composition is cured to form a solid polymer electrolyte. The solid polymer electrolyte composition may further include an initiator that triggers this crosslinking reaction. The initiator may preferably be a photoinitiator, and the crosslinking reaction may occur by irradiation of ultraviolet rays.

Examples of the photoinitiator include 1-phenyl-2-hydroxy-2-methyl propane-1-one (1-phenyl-2-hydroxy-2-methyl propane-1-one; HMPP), phenylbis (2,4 ,6-trimethylbenzoyl)phosphine oxide, chloroacetophenone, Diethoxy Acetophenone, Hydroxy acetophenone, 1-hydroxycyclohexyl phen ketoylne , α-Aminoacetophenone, Benzoin Ether, Benzyl Dimethyl Ketal, Benzophenone, and Thioxanthone, and are necessarily limited to these. This does not mean that they can be used individually or in combination of two or more types.

Additionally, the initiator may be included in an amount of 0.001 to 10 parts by weight, specifically 0.03 to 3 parts by weight, based on 100 parts by weight of the total monomers.

When the initiator is included in an amount within the range of 0.001 to 10 parts by weight, the curing conversion rate can be increased to form a stable solid polymer electrolyte film, and the pre-gel reaction can be prevented, improving the durability of the solid electrolyte composition over time. Changes can be minimized.

The solid polymer electrolyte composition according to the present invention can form a solid polymer electrolyte through a crosslinking reaction between the monomers. Preferably, the solid polymer electrolyte composition containing the monomers, a plasticizer, a lithium salt, and an initiator may be manufactured by irradiating UV light to undergo photopolymerization and crosslinking reactions.

To prepare a solid electrolyte, after forming a polymer cross-linked structure by UV irradiation as described above, a step of drying the obtained material may be further included.

The drying step may be carried out for several hours under hot air or vacuum drying conditions.

6) Organic solvent

In a preferred embodiment of the present invention, the solid polymer electrolyte composition may further include an organic solvent to adjust viscosity or to improve solubility between monomers used. Organic solvents that can be used include tetrahydrofuran, 2-methyl tetrahydrofuran, dimethylformamide (DMF), acetonitrile, N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide ( DMSO), dimethylacetamide (DMAc), dichloromethane, acetone, isopropyl alcohol, methyl ethyl ketone (MEK), etc., but are not necessarily limited to these, and include one or more of these. You can select and use.

(2) solid polymer electrolyte

Additionally, the present invention relates to a solid polymer electrolyte in which the solid polymer electrolyte composition is cured through polymerization and crosslinking reactions.

The curing method is not particularly limited, and the composition can be cured by polymerizing and crosslinking the monomers in the composition through methods commonly known in the art as described above.

Specifically, a solid polymer electrolyte can be prepared by coating the solid polymer electrolyte composition on the surface of a film or electrode, and curing the solid polymer electrolyte composition by polymerizing and crosslinking by irradiating ultraviolet rays.

The coating method may use known coating methods such as slot die, gravure coating, spin coating, spray coating, roll coating, casting, screen printing, or inkjet printing.

The solid polymer electrolyte according to the present invention manufactured by this method may have a lithium salt and a plasticizer evenly dispersed within a polymer matrix of a three-dimensional network structure formed by a cross-linking reaction of monomers contained in the composition. . Therefore, the polymer solid electrolyte of the present invention can exhibit high ionic conductivity at low temperatures.

Preferably, the polymer matrix may be one in which the first monomer and the second monomer are polymerized and cross-linked in a random order to form a three-dimensional network structure. This structure can reduce crystallinity by suppressing interactions between polymer chains in the solid polymer electrolyte compared to a conventional polymer matrix in the form of a block copolymer, and can improve ionic conductivity at low temperatures.

(3) Lithium secondary battery

In addition, the present invention provides a lithium secondary battery including a positive electrode; a negative electrode; and a solid polymer electrolyte according to the present invention.

The lithium secondary battery can be manufactured according to conventional methods known in the art. For example, it can be manufactured by applying the solid polymer electrolyte composition on the positive electrode, curing the composition, and stacking the negative electrode.

1) anode

The positive electrode current collector is not particularly limited as long as it is conductive without causing chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel. , surface treated with nickel, titanium, silver, etc. can be used.

The positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium, and may specifically include a lithium composite metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel, or aluminum. there is. More specifically, the lithium composite metal oxide is lithium-manganese-based oxide (for example, LiMnO ₂ , LiMn ₂ O ₄ , etc.), lithium-cobalt-based oxide (for example, LiCoO ₂ , etc.), lithium-nickel-based oxide. (e.g. LiNiO ₂ etc.), lithium-nickel-manganese oxide (e.g. LiNi _1-Y MnYO ₂ (where 0<Y<1), LiMn _2-z Ni _z O ₄ (here , 0<Z<2), etc.), lithium-nickel-cobalt-based oxide (for example, LiNi _1-Y1 Co _Y1 O ₂ (where 0<Y1<1), etc.), lithium-manganese-cobalt-based oxide (For example, LiCo _1-Y2 Mn _Y2 O ₂ (where 0<Y2<1), LiMn _2-z1 Co _z1 O ₄ (where 0<Z1<2), etc.), lithium-nickel-manganese -Cobalt-based oxide (for example, Li(Ni _p Co _q Mn _r1 )O ₂ (where 0<p<1, 0<q<1, 0<r1<1, p+q+r1=1) or Li(Ni _p1 Co _q1 Mn _r2 )O (here, 0 < p1 < 2, 0 < q1 < 2, 0 < r2 < 2, p1 + q1 + r2 = 2), etc.), or lithium-nickel-cobalt-transition metal (M) oxide (e.g. , Li(Ni _p2 Co _q2 Mn _r3 M _S2 )O ₂ (where M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg and Mo, and p2, q2, r3 and s2 are The atomic fractions of each independent element include 0＜p2＜1, 0＜q2＜1, 0＜r3＜1, 0＜s2＜1, p2+q2+r3+s2=1)), etc. , any one or two or more of these compounds may be included.

Among these, in that the capacity characteristics and stability of the battery can be improved, the lithium composite metal oxide is LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , lithium nickel manganese cobalt oxide (for example, Li(Ni _1/3 Mn _1/3 Co _{1 /3} )O ₂ , Li(Ni _0.6 Mn _0.2 Co _0.2 )O ₂ , Li(Ni _0.5 Mn _0.3 Co _0.2 )O ₂ , Li(Ni _0.7 Mn _0.15 Co _0.15 )O ₂ and Li(Ni _0.8 Mn _0.1 Co _0.1 )O ₂ , etc.), or lithium nickel cobalt aluminum oxide (for example, Li(Ni _0.8 Co _0.15 Al _0.05 )O ₂ , etc.).

The positive electrode active material may be included in an amount of 80% to 99% by weight based on the total weight of solids in the positive electrode slurry.

The binder is a component that assists in the bonding of the active material and the conductive material and the bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of solids in the positive electrode slurry. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, and tetrafluoride. Roethylene, polyethylene, polypropylene, ethylene-propylene-diene termonomer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, and various copolymers.

The conductive material is typically added in an amount of 1 to 30% by weight based on the total weight of solids in the positive electrode slurry.

These conductive materials are not particularly limited as long as they are conductive without causing chemical changes in the battery. For example, carbon black, acetylene black (or Denka black), Ketjen black, channel black, furnace black, lamp black, or carbon powder such as thermal black; Graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.

The solvent may include an organic solvent such as NMP (N-methyl-2-pyrrolidone), and may be used in an amount that provides a desirable viscosity when including the positive electrode active material and optionally a binder and a conductive material. For example, the solid content concentration in the slurry containing the positive electrode active material and, optionally, the binder and the conductive material may be 50% by weight to 95% by weight, preferably 70% by weight to 90% by weight.

2) cathode

Additionally, the negative electrode can be manufactured by forming a negative electrode mixture layer on the negative electrode current collector. The negative electrode mixture layer can be formed by coating a negative electrode slurry containing a negative electrode active material, a binder, a conductive material, and a solvent on a negative electrode current collector, followed by drying and rolling.

The negative electrode current collector generally has a thickness of 3 to 500 μm. This negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel. Surface treatment with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used.

In addition, like the positive electrode current collector, the bonding power of the negative electrode active material can be strengthened by forming fine irregularities on the surface, and can be used in various forms such as films, sheets, foils, nets, porous materials, foams, and non-woven materials.

In addition, the negative electrode active material is lithium metal, a carbon material capable of reversibly intercalating/deintercalating lithium ions, a metal or an alloy of these metals and lithium, a metal complex oxide, and a material capable of doping and dedoping lithium. It may include at least one selected from the group consisting of a material and a transition metal oxide.

As the carbon material capable of reversibly intercalating/deintercalating lithium ions, any carbon-based anode active material commonly used in lithium ion secondary batteries can be used without particular restrictions, and representative examples include crystalline carbon, Amorphous carbon or a combination thereof can be used.

Examples of the crystalline carbon include graphite such as amorphous, plate-shaped, flake-shaped, spherical or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon (low-temperature calcined carbon). Alternatively, hard carbon, mesophase pitch carbide, calcined coke, etc. may be mentioned.

The metal complex oxides include PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , Bi ₂ O ₅ , Li _x Fe ₂ O ₃ (0≤x≤1), Li _x WO ₂ (0≤x≤1), and Sn _x Me _1-x Me _'y O _z (Me: Mn, Fe , Pb, Ge': Al, B, P, Si, group 1, 2, and 3 elements of the periodic table, 0<x≤1; 1≤z≤8) Any selected from the group may be used.

Materials capable of doping and dedoping the lithium include Si, SiO _x (0<x≤2), a Si-Y alloy (wherein Y is an element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, transition metals, rare earth elements, and combinations thereof, but is not Si), Sn, SnO ₂ , Sn-Y (wherein Y is an element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, transition metals, rare earth elements, and combinations thereof, but is not Sn), and the like. In addition, at least one of these may be mixed with SiO ₂ for use. The above element Y may be selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po, and combinations thereof.

Examples of the transition metal oxide include lithium-containing titanium complex oxide (LTO), vanadium oxide, and lithium vanadium oxide.

The negative electrode active material may be included in an amount of 80% to 99% by weight based on the total weight of solids in the negative electrode slurry.

The binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of solids in the negative electrode slurry. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, and tetrafluoride. Roethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber, and various copolymers thereof.

The conductive material is a component to further improve the conductivity of the negative electrode active material, and may be added in an amount of 1 to 20% by weight based on the total weight of solids in the negative electrode slurry. These conductive materials may be the same as or different from the conductive materials used in manufacturing the anode, and may be, for example, carbon black, acetylene black (or Denka black), Ketjen black, channel black, furnace black, lamp black, or thermal black. carbon powder, etc.; Graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.

The solvent may include water or an organic solvent such as NMP or alcohol, and may be used in an amount that provides a desirable viscosity when including the negative electrode active material and optionally a binder and a conductive material. For example, the solid content concentration in the slurry containing the negative electrode active material and optionally the binder and the conductive material may be 50% by weight to 95% by weight, preferably 70% by weight to 90% by weight.

A lithium secondary battery comprising the positive and negative electrodes described above and the solid polymer electrolyte according to the present invention maintains the electrochemical stability of the solid polymer electrolyte, but crystallization of the electrolyte is suppressed at low temperatures, so the output of the battery does not significantly decrease even at low temperatures. It has the advantage of maintaining excellent lithium ion mobility and excellent ion conductivity.

Hereinafter, the configuration and effects of the present invention will be described in more detail through specific examples. However, the scope of the present invention is not limited to the following examples, and those skilled in the art can easily make changes within the scope of the technical idea of the present invention by substituting or adding to the structure of the present invention from the content described in the claims. You will be able to.

Synthesis Example 1

10 g of 4-hydroxy-1,3-dioxolan-2-one was dissolved in 100 mL of dichloromethane. Afterwards, 1.1 equivalents of triethylamine and methacryloyl chloride were added dropwise at 0°C and stirred at room temperature for 24 hours to produce (2-oxo-1,3-dioxolan-4-yl)methyl. Methacrylate ((2-oxo-1,3-dioxolan-4-yl)methyl methacrylate) was obtained. The resulting material was dissolved in DMF, and then 0.5 equivalent of 1,2-bis(2-aminoethoxy)ethane was dissolved together with benzyltriethylammonium chloride. chloride) was added in the amount of 0.01 equivalent and stirred while maintaining the temperature at 80°C, and the reaction proceeded for 4 hours to synthesize the first monomer ITM 1 of the structure below.

<ITM 1>

Synthesis Example 2

In Synthesis Example 1, instead of 1,2-bis(2-aminoethoxy)ethane, poly(ethylene glycol) bis(amine) (Poly(ethylene glycol) bis( The first monomer ITM 2 was synthesized in the same manner except that amine), Mn=2000) was used.

<ITM 2>

Synthesis Example 3

The first monomer ITM 3 was synthesized in the same manner as in Synthesis Example 1 except that 2,6-diamniopyridine was used instead of 1,2-bis(2-aminoethoxy)ethane. did.

<ITM 3>

Synthesis Example 4

In Synthesis Example 1, 4,4'-diamino-2,2'-bisphenyldicarboxylic acid (4,4'-Diamino-2,2'-) was used instead of 1,2-bis(2-aminoethoxy)ethane. The first monomer ITM 4 was synthesized in the same manner except for using biphenyldicarboxylic acid.

<ITM 4>

Synthesis Example 5

In Synthesis Example 1, 2,2-bis(4-aminophenyl)hexafluoropropane was used instead of 1,2-bis(2-aminoethoxy)ethane. The first monomer ITM 5 below was synthesized in the same manner except that.

<ITM 5>

Synthesis Example 6

Same as Synthesis Example 1 except that 4,6-diamino-2-pyrimidinethiol was used instead of 1,2-bis(2-aminoethoxy)ethane. The first monomer ITM 6 was synthesized using the following method.

<ITM 6>

Synthesis Example 7

8 g of 4-hydroxymethyl-1,3-dioxolan-2-one was dissolved in 100 mL of dichloromethane. Afterwards, 1.1 equivalents of triethylamine and bromobut-2-enyl chloride (bromobut-2-enyl chloride) were added dropwise at 0°C and stirred at room temperature for 24 hours to produce (2-oxo-1,3-diox) Solan-4-yl)methyl-6-bromo-2-methylidenehexanoate was obtained.

The resulting material was dissolved in DMF, then 0.5 equivalent of 1,2-bis(2-aminoethoxy)ethane was dissolved together, 0.01 equivalent of benzyltriethylammonium chloride was added, and the temperature was maintained at 80° C. while stirring and stirring. The reaction was carried out over time to synthesize the first monomer ITM 7 with the following structure.

<ITM 7>

Example 1

ITM 1 synthesized in Synthesis Example 1 as the first monomer, trimethylolpropane ethoxylate triacrylate (formula 2-4-1 below) as the second monomer, and LiTFS I (Lithium bis(trifluoromethanesulfonyl) as the lithium salt. )imide, (Formula 4-1 below), Succinonitrile (Formula 5-1 below) as a plasticizer are mixed in a weight ratio of 5:10:23:62, and Irgacure 819 as a photoinitiator is mixed with the first and second monomers. A solid polymer electrolyte composition was prepared by adding 0.05 parts by weight based on the total of 100 parts by weight. The prepared solid electrolyte composition was applied on a glass plate and irradiated with UV light with a wavelength of 365 nm for 5 minutes to prepare a 200㎛ solid polymer electrolyte membrane.

The solid polymer electrolyte membrane was peeled off from the glass plate, and the solid polymer electrolyte membrane was stacked between them using lithium metal as an electrode, and then manufactured as a 2032 coin cell for measuring ionic conductivity.

In addition, a coin cell for measuring electrochemical stability was manufactured by stacking the same electrolyte membrane between lithium metal and stainless steel as electrodes.

[Formula 2-4-1]

[Formula 4-1]

[Formula 5-1]

Examples 2 to 6

A solid polymer electrolyte was prepared in the same manner as in Example 1, but the mixing weight ratio of ITM 1 / second monomer / LiTFSI / Succinonirile was varied as shown in Table 1. A solid electrolyte composition was prepared for measuring ion conductivity in the same manner as 2032. A coin cell and a coin cell for measuring electrochemical stability were manufactured.

Examples 7 to 10

ITM 2 was used as the first monomer, PEGDA (Poly(ethylene glycol) diacrylate: Mw 700, Formula 3 below) was used as the second monomer, LiClO ₄ was used as the lithium salt, and 1-butyl-3-methylimidazolium bis ( Trifluoromethanesulfonyl)imide (1-butyl-3-methylimidazolium bis(trifluoromethansulfonyl)imide, Chemical Formula 5-2 below) was varied in its content as shown in Table 2, and the solid polymer was prepared in the same manner as in Example 1. An electrolyte composition was prepared.

The prepared solid electrolyte compositions were again manufactured into a solid electrolyte membrane in the same manner as in Example 1, and were used to manufacture a 2032 coin cell for measuring ionic conductivity and a coin cell for measuring electrochemical stability.

[Formula 3]

Examples 11-15

ITM 3 prepared according to Synthesis Example 3 as the first monomer, 3-(Acryloyloxy)-2-hydroxypropyl methacrylate as the second monomer, Formula 2 below -5) was used, LiTFSI and LiBOB (lithium bis(oxalate)borate, following formula 4-2) were mixed at a weight ratio of 1:1 as a lithium salt, and succinonitrile was used as a plasticizer as shown in Tables 2 and 3. Likewise, a solid polymer electrolyte composition was prepared with Irgacure 819, a photoinitiator, by varying the respective contents. The prepared solid polymer electrolyte compositions were manufactured in the same manner as in Example 1 into a solid polymer electrolyte membrane and a 2032 coin cell for measuring ionic conductivity and a coin cell for measuring electrochemical stability using the same.

[Formula 2-5]

[Formula 4-2]

Examples 16-19

As the first monomer, Example 16 was ITM 4 synthesized according to Synthesis Example 4, Example 17 was ITM 5 synthesized according to Synthesis Example 5, Example 18 was ITM 6 synthesized according to Synthesis Example 6, and Example 19 was ITM 4 synthesized according to Synthesis Example 6. ITM 7 synthesized according to Synthesis Example 7, trimethylol ethoxylate triacrylate as the second monomer, LiNO ₃ as the lithium salt, and succinonitrile as the plasticizer were mixed in a weight ratio of 5:10:25:50. A solid polymer electrolyte composition was prepared by adding 0.05 parts by weight of Irgacure 819 as a photoinitiator based on 100 parts by weight of the polyfunctional monomer. A solid polymer electrolyte membrane was prepared from the prepared solid polymer electrolyte composition in the same manner as in Example 1, and a 2032 coin cell for measuring ionic conductivity and a coin cell for measuring electrochemical stability were manufactured.

Comparative Example 1

Using the monomer PEGDA (Mw 700) having a two-functional group, LiTFSI as the lithium salt and succinonitrile as the plasticizer were mixed in a weight ratio of PEGDA:lithium salt:plasticizer of 20:30:50, and the photoinitiator Irgarcure 819 was mixed with the monomer 100. A solid polymer electrolyte composition was prepared by mixing an additional 0.05 parts by weight. In addition, a solid polymer electrolyte membrane was prepared in the same manner as in Example 1, and a 2032 coin cell for measuring ionic conductivity and a coin cell for measuring electrochemical stability were manufactured using it.

Comparative Example 2

PEO (polyethylene oxide: Mw 10,000) as an ion conductive polymer, LiTFSI as a lithium salt, and succinonitrile as a plasticizer are used. The ion conductive polymer: lithium salt: plasticizer is mixed in a weight ratio of 20:30:50 and dissolved in the solvent THF. Afterwards, it was cast on a glass plate.

A solid polymer electrolyte membrane was prepared by volatilizing the solvent from the mixture cast on the glass plate at a temperature of 50°C. The solid polymer electrolyte membrane was manufactured in the same manner as Example 1 into a 2032 coin cell for measuring ionic conductivity and a coin cell for measuring electrochemical stability.

Comparative Example 3

Using PEO as an ion conductive polymer and PEGDA (Mw 700) as a bifunctional monomer, LiTFSI as a lithium salt, and succinonitrile as a plasticizer, the mixing weight ratio of polyethylene oxide: monomer: lithium salt: plasticizer was 20:5:25:50. A solid polymer electrolyte composition was prepared by dissolving in THF solvent and adding 0.05 parts by weight of photoinitiator Irgacure 819 based on 100 parts by weight of monomer.

The solid polymer electrolyte composition was manufactured into a solid polymer electrolyte membrane using the same method as that presented in Example 1, and was used to manufacture a 2032 coin cell for measuring ionic conductivity and a coin cell for measuring electrochemical stability.

Experimental Example 1

The ionic conductivity of the solid polymer electrolyte can be obtained by measuring the impedance and using Equation 1 below. A sample of a 2032 coin cell for measuring ionic conductivity manufactured according to Examples and Comparative Examples was brought into contact with a substrate, and then an alternating current voltage was applied through electrodes on both sides of the sample. At this time, the measurement frequency was set to an amplitude range of 1.0 MHz to 0.1 Hz as the applied condition, and the impedance was measured using VMP3 from BioLogic. The resistance of the bulk electrolyte was calculated from the intersection point where the semicircle or straight line of the measured impedance trace meets the real side, and the ionic conductivity of the polymer solid electrolyte membrane was calculated from the area and thickness of the sample.

[Equation 1]

.

σ: Ion conductivity (mS/cm)

R: Intersection between the impedance trace and the real axis

A: Area of solid electrolyte membrane

t: Thickness of solid electrolyte membrane

The ionic conductivity values measured in this way are shown in Tables 1 to 4 below, respectively.

Experimental Example 2

To measure electrochemical stability, a coin cell was manufactured by using stainless steel as the measuring electrode and lithium metal as the counter electrode, inserting the manufactured electrolyte membrane between these electrodes, and linear scanning voltammetry up to 6V at a scan rate of 5mV/s. Electrochemical stability was measured through (Linear Sweep Voltammetry, LSV). The results are shown in Tables 1 to 4 below, respectively.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 composition
ingredient Ion conductivity
polymer first monomer type ITM 1 ITM 1 ITM 1 ITM 1 ITM 1 ITM 1 content 5 10 10 20 30 15 second monomer type Chemical formula 2-4-1 Chemical formula 2-4-1 Chemical formula 2-4-1 Chemical formula 2-4-1 Chemical formula 2-4-1 Chemical formula 2-4-1 content 10 5 10 5 5 15 lithium salt type LiTFSI LiTFSI LiTFSI LiTFSI LiTFSI LiTFSI content 23 30 30 25 30 20 plasticizer type Formula 5-1 Formula 5-1 Formula 5-1 Formula 5-1 Formula 5-1 Formula 5-1 content 62 50 50 55 35 50 Ion conductivity
(mS/cm) 1.5 1.7 1.3 1.4 1.2 1.3 Electrochemical stability
(V) 5.2 5.0 4.9 5.1 4.8 4.8

Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 composition
ingredient Ion conductivity
polymer first monomer type ITM 2 ITM 2 ITM 2 ITM 2 ITM 3 ITM 3 content 5 10 10 20 5 10 second monomer type PEGDA PEGDA PEGDA PEGDA Formula 2-5 Formula 2-5 content 10 5 10 5 10 5 lithium salt type LiClO ₄ LiClO ₄ LiClO ₄ LiClO ₄ LiTFSI, LiBOB LiTFSI, LiBOB content 23 30 30 25 23 30 Plasticizer type Formula 5-2 Formula 5-2 Formula 5-2 Formula 5-2 Formula 5-1 Formula 5-1 content 62 50 50 55 62 50 Ion conductivity
(mS/cm) 1.6 1.8 1.3 1.4 1.5 1.4 Electrochemical stability
(V) 4.8 4.9 5.0 5.0 4.9 4.7

Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 composition
ingredient ion
conductivity
polymer first monomer type ITM 3 ITM 3 ITM 3 ITM 4 ITM 5 ITM 6 ITM 7 content 10 20 30 5 5 5 5 second monomer type Formula 2-5 Formula 2-5 Formula 2-5 Chemical formula 2-4-1 Chemical formula 2-4-1 Chemical formula 2-4-1 Chemical formula 2-4-1 content 10 5 5 10 10 10 10 lithium salt type LiTFSI, LiBOB LiTFSI, LiBOB LiTFSI, LiBOB LINO ₃ LINO ₃ LINO ₃ LiNO _3[ content 30 25 30 25 25 25 25 plasticizer type Formula 5-1 Formula 5-1 Formula 5-1 Formula 5-1 Formula 5-1 Formula 5-1 Formula 5-1 content 50 55 35 50 50 50 50 Ion conductivity
(mS/cm) 1.1 1.0 1.2 1.7 1.3 1.4 1.7 Electrochemical stability
(V) 4.8 4.9 5.0 5.1 5.0 5.2 5.1

Comparative Example 1 Comparative Example 2 Comparative Example 3 composition
ingredient Ion conductivity
polymer polymer type - PEO PEO content - 20 20 second monomer type PEGDA - PEGDA content 20 - 5 lithium salt type LiTFSI LiTFSI LiTFSI content 30 30 25 plasticizer type Formula 5-1 Formula 5-1 Formula 5-1 content 50 50 50 Ion conductivity
(mS/cm) 0.2 0.02 0.05 Electrochemical stability (V) 4.2 4.2 4.3

The coin cell containing a solid electrolyte prepared using ITM 1 as the first monomer and trimethylolpropane ethoxylate triacrylate as the second monomer as in Examples 1 to 6 had an ionic conductivity of 1 mS/ at room temperature. It was confirmed that it showed a high value of more than cm and had high electrochemical stability of more than 4.0V. This is due to the presence of functional groups that can increase the solubility of lithium salt, such as hydroxyl and urethane groups, in the network-structured solid polymer electrolyte manufactured through UV curing, and the anion of the lithium salt is coordinated to facilitate the movement of lithium ions, thereby increasing ionic conductivity at low temperatures. is judged to improve.

In addition, in each example, as the content of the plasticizer increases, the transfer of lithium ions becomes easier, but as the content of the second monomer gradually increases, the chain mobility between the polymers of the polythioether present decreases, generally It was confirmed that the ionic conductivity decreased slightly.

However, in Comparative Example 1, only monomers having two functional groups constituted the polymer matrix of the polymer electrolyte membrane, so the cured density was increased and the fluidity of the polymer chain was relatively reduced, resulting in low ionic conductivity at room temperature.

Comparative Example 2 is a polymer electrolyte manufactured using polyethylene oxide, which has been used conventionally. It was found that despite the use of a plasticizer, it was difficult to secure satisfactory ionic conductivity due to high crystallinity at room temperature.

Comparative Example 3 includes a solid polymer electrolyte having a semi-IPN structure using polyethylene oxide, which has been used conventionally, as an ion conductive polymer, but also using bifunctional monomers. The specific gravity of polyethylene oxide as an ion conductive polymer is high, so it can be used at low temperatures. It is believed that it shows low ionic conductivity because it is difficult to lower the crystallinity.

Claims (17)

Monomer compound for polymer electrolyte, characterized in that represented by the following formula 1-1:
[Formula 1-1]

In Formula 1-1,
A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ hetero One or two or more selected from arylene groups are combined,
R ¹⁰ is each independently hydrogen, an alkyl group of C ₁ to C ₆ , a haloalkyl group of C ₁ to C ₆ , a heteroalkyl group of C ₁ to C ₆ , a cycloalkyl group of C ₅ to C ₁₀ , and an aryl group of C ₆ to C ₁₄ group or one selected from C ₃ to C ₁₄ heteroaryl group,
R ¹¹ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group,
R ¹² is an alkylene group of C ₂ to C ₁₀ , and n10 is an integer of 0 to 10.
delete According to paragraph 1,
The above compound is a monomer compound for polymer electrolyte, characterized in that it is a compound represented by the following formula 1-2:
[Formula 1-2]

In Formula 1-2,
A ¹⁰ is -R ¹² -(OR ¹² ) _n10 -, C ₂ ~ C ₁₀ alkylene group, C ₅ ~ C ₁₄ cycloalkylene group, C ₆ ~ C ₁₄ arylene group, and C ₃ ~ C ₁₄ heteroaryl It is a combination of one or two or more selected from Rengi,
R ¹² is an alkylene group from C ₂ to C ₁₀
R ¹³ is hydrogen or a methyl group, and n10 is an integer from 0 to 10.
According to paragraph 1,
The above compound is a monomer compound for polymer electrolyte, characterized in that it is a compound represented by the following formula 1-3:
[Formula 1-3]

In Formula 1-3,
R ¹³ is hydrogen or a methyl group, and n10 is an integer from 0 to 10.
A first monomer consisting of the monomer compound for polymer electrolyte according to claim 1; A second monomer having two or more ethylenically unsaturated functional groups and capable of forming a crosslinked structure; and a lithium salt. A solid polymer electrolyte composition comprising a lithium salt.
According to clause 5,
A solid polymer electrolyte composition, wherein the ethylenically unsaturated functional group of the second monomer is a vinyl group or an acryloyl group.
According to clause 6,
A solid polymer electrolyte composition, wherein the second monomer includes at least one of the compounds represented by the following formulas 2-1 to 2-3:
[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

In Formulas 2-1 to 2-3,
R ²⁰ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group,
R ²¹ is each independently a C ₁ to C ₁₀ alkylene group, a C ₅ to C ₁₄ cycloalkylene group, a C ₆ to C ₁₄ arylene group, a C ₃ to C ₁₃ heteroarylene group, or a C 1 to C 10 haloalkyl group. It's Rengi,
R ²² is each independently -(O ^* CH ₂ CH ₂ )(OCH ₂ CH ₂ ) _a1 -, -(O ^* CH ₂ CH(CH ₃ ))(OCH ₂ CH(CH ₃ )) _a2 - or -( O ^* CH ₂ CH ₂ )(OCH ₂ CH ₂ ) _a1 (OCH ₂ CH(CH ₃ )) _a3 -,
The oxygen (O ^* ) marked with * is bonded to R ²¹ ,
The a1 and a2 are each independently an integer from 0 to 10, and a3 is an integer from 1 to 10.
According to clause 6,
A solid polymer electrolyte composition, wherein the second monomer is a compound represented by the following formula 2-4:
[Formula 2-4]

In Formula 2-4, b is each independently an integer of 1 to 5.
According to clause 6,
A solid polymer electrolyte composition, characterized in that the second monomer is a compound represented by the following formula (3):
[Formula 3]

In Formula 3 above,
R ³⁰ is each independently hydrogen, a C ₁ to C ₆ alkyl group, a C ₁ to C ₆ haloalkyl group, or a C ₁ to C ₆ heteroalkyl group.
According to clause 5,
The solid polymer electrolyte composition is characterized in that it contains 3 to 60% by weight of the first monomer and 5 to 50% by weight of the second monomer.
According to clause 5,
The lithium salt contains Li ⁺ as a cation, and F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , N(CN) ₂ ^- , ClO ₄ ^- , BF ₄ ^- , AlO ₄ ^- , AlCl as anions. 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 ^- , (FSO ₂ ) ₂ N ^- , CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , (SF ₅ ) ₃ C ^- , (CF ₃ SO ₂ ) ₃ C ^- , 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 ^- containing at least one selected from the group consisting of A solid polymer electrolyte composition characterized by:
According to clause 5,
A solid polymer electrolyte composition, characterized in that the content of lithium salt in the solid polymer electrolyte composition is 10 to 40% by weight based on the total composition.
According to clause 5,
The solid polymer electrolyte composition is characterized in that it further comprises a plasticizer and an initiator.
According to clause 13,
The plasticizer is succinonitrile, glutaronitrile, polyethylene glycol dimethylether, tetraethylene glycol, ethylene carbonate, propylene carbonate, and tetraethylene glycol. Ethylene glycol dimethylether (tetraglyme), dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, cyclic phosphate phosphate), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide], 1-butyl-3-methylimidazolium bis (Trifluoromethanesulfonyl)imide [1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide], N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide [N-methyl- N-propylpiperidinium bis(trifluoromethanesulfonyl)imide], 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, N-butyl-N-ethylpyrrolidinium bis(tri A solid polymer electrolyte composition comprising at least one selected from fluoromethanesulfonyl)imide [N-butyl-Nethylpyrrolidinium bis(trifluoromethanesulfonyl)imide].
A solid polymer electrolyte formed by curing the solid polymer electrolyte composition according to claim 5.
According to clause 15,
The solid polymer electrolyte is characterized in that it contains a polymer having a three-dimensional network structure in which the first monomer and the second monomer are polymerized and cross-linked to each other.
anode; cathode; And a lithium secondary battery comprising the solid polymer electrolyte according to claim 15.