KR102230649B1 - Electrolyte, preparing method thereof, and secondary battery comprising the electrolyte - Google Patents

Abstract

It is a block copolymer containing a double-linked domain (co-continuous domain) including an ion conducting phase (conductive phase) and a structural phase (structural phase) , the structure is an electrolyte comprising a polymer segment having a glass transition temperature of less than room temperature, A method of manufacturing the same and a secondary battery including the same are provided.

Description

Electrolyte, manufacturing method thereof, and secondary battery comprising the same {Electrolyte, preparing method thereof, and secondary battery comprising the electrolyte}

An electrolyte, a method of manufacturing the same, and a secondary battery including the same are provided.

The lithium secondary battery is a high-performance secondary battery having the highest energy density among the currently commercialized secondary batteries, and can be used in various fields such as, for example, electric vehicles. Lithium secondary batteries suitable for electric vehicles can operate at high temperatures, and must be used for a long time after charging or discharging a large amount of electricity.

Polyethylene oxide electrolyte is known as an electrolyte used in a lithium secondary battery. Such an electrolyte exhibits excellent ionic conductivity at a high temperature of 60° C. or higher, but the ionic conductivity decreases at room temperature.

As another example of the electrolyte, a polyethylene oxide-polystyrene block copolymer electrolyte is known. These electrolytes do not reach a satisfactory level in mechanical properties, so there is a lot of room for improvement.

One aspect is to provide an electrolyte with improved mechanical properties and a method of manufacturing the same.

Another aspect is to provide a secondary battery with improved cycle efficiency and stability including the electrolyte.

According to one side

It is a block copolymer containing a double-linked domain (co-continuous domain) including an ionic conductive phase (conductive phase) and a structural phase (structural phase),

In the above structure, an electrolyte including a polymer segment having a glass transition temperature of less than or equal to room temperature is provided.

The structure includes a polymer which is a polymerization reaction product of i) a monofunctional polymerizable monomer, ii) a polyfunctional polymerizable monomer, and iii) a polymerizable monomer having a reactive functional group.

Another aspect is a chain transfer agent containing an ion conductive polymer, which is a polymer for forming an ion conductive phase, and i) a monofunctional polymerizable monomer, ii) a polyfunctional polymerizable monomer, and iii) a polymerizable monomer having a reactive functional group, which is a structural polymer forming monomer. It is made by a method for producing an electrolyte for obtaining the above-described electrolyte by carrying out a polymerization reaction of the electrolyte composition containing.

Another aspect is made by a secondary battery including a positive electrode, a negative electrode, and the above-described electrolyte interposed therebetween.

The electrolyte according to an embodiment has improved mechanical properties. The use of such an electrolyte increases cycle efficiency and safety.

1A to 1E schematically show the structure of a lithium battery including an electrolyte according to an embodiment.
1F is an exploded perspective view of a lithium battery according to another embodiment.
2A shows the results of evaluation of ionic conductivity of electrolytes prepared according to Examples 1-2 and Comparative Example 1. FIG.
2B shows the results of evaluation of ionic conductivity of electrolytes prepared according to Examples 2, 3 and 8 and Comparative Examples 1 and 4.
3 shows the results of linear sweep voltammetry (LSV) analysis of the electrolyte according to Example 1. FIG.
4A shows the impedance measurement results of coin cells manufactured according to Preparation Example 1 and Comparative Preparation Example 1. FIG.
Figure 4b shows the impedance measurement results of the coin cell manufactured according to Comparative Production Example 1.
Figure 4c shows the impedance measurement result of the coin cell manufactured according to Preparation Example 2
will be.
Figure 4d shows the impedance measurement result of the coin cell manufactured according to Comparative Production Example 2
will be.
5A is a photograph showing a state of an electrolyte after charging and discharging in a coin cell according to Comparative Production Example 3. FIG.
5B shows the charging profile of the coin cell according to Comparative Production Example 3 after performing the charging process.
6A to 6C are according to Production Example 1, Comparative Production Example 1, and Comparative Production Example 2
It shows the potential change according to the capacity after performing the charging/discharging process in the manufactured coin cell.
7 is a graph showing charge/discharge characteristics in a coin cell manufactured according to Preparation Example 2.
8 is a graph showing a change in capacity in a lithium secondary battery manufactured according to Preparation Example 8. FIG.
9 is a graph showing voltage changes according to capacity in a lithium secondary battery manufactured according to Preparation Example 8. FIG.
10 shows the capacity change in the lithium secondary battery manufactured according to Preparation Example 9 and Comparative Preparation Example 4.

Hereinafter, exemplary electrolytes, a method of manufacturing the same, and a secondary battery including the electrolyte will be described in more detail below with reference to the accompanying drawings.

It is a block copolymer containing a co-continuous domain including an ion conductive phase and a structural phase,

The structure includes a polymer segment having a glass transition temperature of less than room temperature.

The structure includes a polymer which is a polymerization reaction product of i) a monofunctional polymerizable monomer, ii) a polyfunctional polymerizable monomer, and iii) a polymerizable monomer having a reactive functional group.

The structure includes a polymer which is a polymerization reaction product of i) a monofunctional polymerizable monomer, ii) a polyfunctional polymerizable monomer, and iii) a polymerizable monomer having a reactive functional group.

The term “room temperature” refers to about 25°C.

The polymer segment having a glass transition temperature below room temperature is derived from the polymerizable monomer having the above-described reactive functional group, and specifically, the polymerizable monomer having the above-described reactive functional group is polymerized with a monofunctional polymerizable monomer and a polyfunctional polymerizable monomer. It is obtained by carrying out a reaction. Herein, the polymerization reaction includes a polymerization reaction, a crosslinking reaction and/or a graft reaction with a polymerizable monomer having a reactive functional group, a monofunctional polymerizable monomer and a polyfunctional polymerizable monomer.

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The structure includes a polymer including a polymer segment having a high glass transition temperature (Tg) and a polymer segment having a low glass transition temperature (Tg). A high glass transition temperature indicates, for example, a glass transition temperature exceeding room temperature, and is, for example, 30 to 300°C. Here, the term “polymer segment” refers to a partial chain constituting a polymer.

The structure of block copolymers generally used in the manufacture of electrolytes is composed of only polymer segments having a high glass transition temperature in order to realize excellent mechanical properties. Here, a high glass transition temperature means a glass transition temperature exceeding room temperature.

However, the structure constituting the block copolymer in the electrolyte according to an embodiment includes a polymer segment having a low glass transition temperature, specifically, a glass transition temperature of less than room temperature, in addition to the polymer segment having a high glass transition temperature. The glass transition temperature below room temperature means, for example, a glass transition temperature of -50 to 25°C. When the polymer segment having a glass transition temperature below room temperature is contained, the structural polymer and the block copolymer containing the same have excellent elastic properties. The structurally-forming polymer having excellent elasticity can be obtained by reacting the above-described polymerizable monomer having a reactive functional group with a monofunctional polymerizable monomer and a polyfunctional polymerizable monomer.

The content of the polymer segment having a low glass transition temperature in the polymer including the polymer segment having a high glass transition temperature (Tg) and a polymer segment having a low glass transition temperature (Tg) described above in terms of structure is, for example, a polymer for structural formation. (Total of polymer segments having a high glass transition temperature and polymer segments having a low glass transition temperature) 0.2 to 0.7 moles based on 1 mole.

The term “polymerization reaction product” refers to a product obtained from a polymerization reaction, a crosslinking reaction or a graft reaction, for example, the polymerization reaction product is i) a monofunctional polymerizable monomer, ii) a polyfunctional polymerizable monomer, and iii) reactivity It may mean a crosslinked copolymerization reaction product of an elastically retaining polymerizable monomer having a functional group. The crosslinking copolymerization reaction product is a product obtained from a crosslinking copolymerization reaction and/or a product obtained from a graft copolymerization reaction.

The size of the double-linked domain is 1 μm or more.

As an electrolyte for a lithium secondary battery, a polyethylene oxide-polystyrene block copolymer electrolyte is known. In this electrolyte, the ion conducting phase is made of polyethylene oxide, and the structure is made of polystyrene having a high glass transition temperature. However, such an electrolyte has good ionic conductivity at room temperature, but its mechanical properties are insufficient, so that a crack is formed during operation of the battery, resulting in a short circuit in the battery. In addition, when the above-described electrolyte is used as a lithium negative electrode protective film, the effect of suppressing the formation of dendrite of lithium metal is insignificant, and there is much room for improvement.

Accordingly, the present inventors use a block copolymer having a structure containing a double-linked domain including an ion conductive phase and a structural phase as a polymer for forming an electrolyte, and the size of the double-linked domain is adjusted to be greater than 1 μm compared to the conventional case. . At the same time, the elasticity of the block copolymer is controlled by controlling the composition of the polymer forming the structural phase of the block copolymer. Here, the composition of the polymer forming the structural phase can be adjusted by changing the type and content of the monomer of the starting material used to obtain the polymer.

According to one embodiment, a monofunctional polymerizable monomer, a polyfunctional polymerizable monomer, and an elastically retaining polymerizable monomer having a reactive functional group are used as the monomers.

The block copolymer having the size of the double-linked domain described above can be obtained by a reversible addition-fragmentation chain transfer (RAFT) reaction. In the case of such a RAFT reaction, it can be carried out using a chain transfer agent. When the RAFT reaction is performed using a chain transfer agent as described above, a block copolymer having a small polydispersity and an extended chain length can be obtained. And the block copolymer is a polymerization product obtained by the polymerization reaction (crosslinked copolymerization reaction) of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the elastically retaining polymerizable monomer having a reactive functional group. ), and retains the elasticity while having the rigidity (integrity). Here, the crosslinking copolymerization reaction may also include a graft copolymerization reaction.

According to an embodiment, the polydispersity (weight average molecular weight (Mw)/number average molecular weight (Mn)) of the block copolymer is 3.0 or less, for example, 1.0 to 2.0, specifically 1.05 to 1.17. And the weight average molecular weight of the block copolymer is 10,000 to 200,000 Daltons, for example, 40,000 to 150,000 Daltons.

When the above-described block copolymer is used, an electrolyte having excellent ionic conductivity and improved mechanical properties can be obtained by performing percolation of nanochannels capable of rapid movement of ions such as lithium ions. As the mechanical properties of the electrolyte are improved, it is possible to prevent the formation of cracks in the electrolyte during the charging and discharging process of the battery. In addition, when such an electrolyte is used as a cathode protective film, the effect of suppressing the formation of dendrite of lithium metal is very excellent. Therefore, it is possible to prevent a short circuit in the battery due to a decrease in mechanical properties of the electrolyte.

Mechanical properties refer to properties that exhibit mechanical strength, such as modulus of elasticity and tensile strength.

In this specification, the "ionic conducting phase" refers to the electrical performance of the block copolymer (for example,

Ionic conductivity). And “structurally” refers to a region mainly responsible for mechanical properties, durability, and thermal stability of the block copolymer. The double-linked domain including the ion conducting phase and the structural phase constitutes a substantially continuous phase and does not have a domain boundary. As such, the absence of domain boundaries can be confirmed through Scanning Electron Microscopy or Gas Sorption Isotherm.

The double-linked domain size is as large as 1 μm or more. For example, the size of the double-linked domain is 1 to 1000 µm, specifically 1 to 100 µm. The fact that the double-linked domain size has the above-described range is determined by using a scanning electron microscope or a transmission electron microscopy, or by a gas sorption isotherm after removing the material of one domain. It can be found by measuring the specific surface area of the obtained internal pores.
As described above, when the size of the double-connected domain is larger than 1 μm, there is an advantage in that excellent ionic conductivity and mechanical properties can be simultaneously secured compared to the case where the size of the double-connected domain is less than 1 μm. In addition, the cross-sectional size of the channel is 1 to 20 nm. As described above, the size of the double-connected domain, the length of the channel, and the cross-sectional size can be confirmed using a scanning electron microscope, a transmission electron microscope, and a gas sorption isotherm.

The length and cross-sectional size of the above-described channel can be controlled by adjusting the chain length of the polymer constituting the ion conducting phase. Here, the cross-sectional size represents the length or diameter of one side with the longest length.

The structure according to an embodiment is a monofunctional polymerizable monomer, a polyfunctional polymerizable monomer, and

It includes a polymer which is a polymerization reaction product of an elastically retaining polymerizable monomer having a reactive functional group. As described above, such a polymer contains a polymer segment having a glass transition temperature below room temperature and a polymer segment having a glass transition temperature exceeding room temperature. The structurally forming polymer contains a polymer segment having a glass transition temperature below room temperature, and exhibits rubber properties at room temperature. As a result, if such a structurally forming polymer is used, an electrolyte having excellent elasticity can be obtained. In addition, the structurally forming polymer contains a polymer segment having a glass transition temperature exceeding room temperature, so that it has glass characteristics at room temperature. By using such a structurally forming polymer, an electrolyte having excellent mechanical properties can be prepared.

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The polymerizable monomer having a reactive functional group has a copolymerizable functional group and a reactive functional group, and the polymer formed by polymerization to form a structural phase has excellent elasticity. Among the polymers forming the structural phase, a polymer segment having a glass transition temperature below room temperature is closely related to excellent elasticity.

Here, any reactive functional group may be used as long as it is a functional group capable of crosslinking reaction and/or graft polymerization. For example, one or more selected from a functional group containing an ethylenically unsaturated bond, a hydroxy group, an amino group, an amide group, a carboxyl group, and an aldehyde group may be mentioned.

According to an embodiment, the elastically retaining polymerizable monomer having a reactive functional group is at least one selected from the group consisting of an acrylic monomer, a methacrylic monomer, and an olefin-based monomer having a reactive functional group. As specific examples of the elastically retaining polymerizable monomer having a reactive functional group, butyl acrylate, 1,6-hexadiene, 1,4-butadiene, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylic Rate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxy Roxypropylene glycol (meth)acrylate, acrylic acid, methacrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth)acryloyloxy butyric acid, Itaconic acid, maleic acid, 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, 4-isocyanatobutyl (meth)acrylate, (meth)acrylamide , N-vinyl pyrrolidone, ethylene di (meth) acrylate, diethylene glycol (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylene propane tri (meth) acrylate, trimethylene propane triacrylic Rate, 1,3-butanediol (meth)acrylate, 1,6-hexanedioldi (meth)acrylate, allyl acrylate, N-vinyl caprolactam, and at least one selected from the compound represented by the following formula (10a).

[Formula 10a]

The monofunctional polymerizable monomer represents a compound having one (co)polymerizable functional group (eg, C=C). For example, styrene, 4-bromostyrene, tertbutylstyrene, methyl methacrylate, isobutyl methacrylate, 4-methylpentene-1, butylene terephthalate, ethylene terephthalate, ethylene, propylene, isobutyl methacrylic Rate, butadiene, dimethylsiloxane, isobutylene, vinylidene fluoride, acrylonitrile, 1-butyl vinyl ether, vinyl cyclohexane, fluorocarbon, cyclohexyl methacrylate, maleic anhydride, maleic acid (maleic acid), methacrylic acid and at least one selected from the group consisting of vinylpyridine.

The polyfunctional polymerizable monomer refers to a compound having two or more reactive functional groups, for example (co)polymerizable functional groups. For example l,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene 1,2,4-trivinylbenzene, 4,4”-divinyl-5'-(4- Vinylphenyl)-1,1': 3',1"-terphenyl, 1,3-divinylnaphthalene, 1,8-divinylnaphthalene, l,3,5-trivinylnaphthalene, 2,4-divinyl Biphenyl, 3,5,7-trivinylnaphthalene, l,2-divinyl-3,4-dimethylbenzene, l,5,6-trivinyl-3,7-diethylnaphthalene, l,3-divinyl -4,5-8-tributylnaphthalene and 2,2'-divinyl-4-ethyl-4'-propylbiphenyl.

According to an embodiment, the monofunctional polymerizable monomer is styrene, the polyfunctional polymerizable monomer is 1,4-divinylbenzene, and the polymerizable monomer having a reactive functional group is butyl acetate, 1,4-hexadiene or It is 1,6-hexadiene. The content of the polymerizable monomer having a reactive functional group in the electrolyte is 0.2 to 0.7 mol, for example 0.4, based on 1 mol of the total of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the elastically retaining polymerizable monomer having a reactive functional group. To 0.6667 moles. In addition, the content of the monofunctional polymerizable monomer is 0.15 to 0.5 moles, for example 0.16665 to 0.44445 moles, based on 1 mole of the total of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the elastically retaining polymerizable monomer having a reactive functional group. to be. The content of the polyfunctional polymerizable monomer is 0.05 to 0.3 mol, for example, 0.1111 to 0.2 mol, based on 1 mol of the total of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the elastically retaining polymerizable monomer having a reactive functional group. .

When the content of the monomer, which is the starting material forming the structural phase, is excellent in the tensile strength and elastic modulus of the finally obtained electrolyte, it is possible to prevent a short circuit inside the battery, as well as excellent mechanical properties and ionic conductivity. Do.

According to an embodiment, the mixing ratio of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the polymerizable monomer having a reactive functional group is 4:1:4, 2:1:2, 1:1:4, or 2:1: It is 4 molar ratio.

The ion-conducting phase is selected from ether-based monomers, acrylic-based monomers, methacrylic-based monomers, amine-based monomers, imide-based monomers, alkyl carbonate-based monomers, nitrile-based monomers, phosphazine-based monomers, olefin-based monomers, diene-based monomers, and siloxane-based monomers. And an ion conductive polymer containing one or more ion conductive repeating units.

The ion conductive repeating unit described above is a region responsible for the ionic conductivity of the block copolymer, and non-limiting examples include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, and 2-ethyl. And those derived from one or more monomers selected from hexyl acrylate, butyl methacrylate, 2-ethyl hexyl methacrylate, decyl acrylate, ethylene vinyl acetate, ethylene oxide, and propylene oxide. As the ion conductive repeating unit, ethoxylated trimethylolpropane triacrylate (ETPTA) may be used.

The ion conductive polymer is, for example, polyethylene oxide, polypropylene oxide, polymethyl methacrylate, polyethyl methacrylate, polydimethylsiloxane, polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polyethyl acrylate, poly2 -Ethylhexyl acrylate, polybutyl methacrylate, poly2-ethylhexyl methacrylate, polydecyl acrylate and polyethylene vinyl acetate, polyimide, polyamine, polyamide, polyalkyl carbonate, polynitrile, polyphosphazines ), polyolefins, polydienes, and one or more selected from the group consisting of.

The structural content is 50% or more, for example 50 to 90%, specifically 50 to 70%, based on the total volume of the electrolyte. When the structural content of the electrolyte is within the above-described range, the electrolyte has excellent mechanical properties. The electrolyte may further include an ionic liquid.

An ionic liquid has a melting point below room temperature and refers to a salt in a liquid state or a molten salt at room temperature at room temperature (25°C) composed of only ions. The ionic liquid is i) ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, tria at least one cation selected from the sol ryumgye, and mixtures thereof, ^{_{and, ii) BF 4 -, PF}} 6 -, AsF 6 -, SbF 6 -, AlCl 4 -, HSO 4 -, ClO 4 -, CH 3 SO 3 -, CF 3 _{^{CO 2 -, (CF 3 SO}} 2) 2 N -, Cl -, Br -, I -, SO 4 -, CF 3 SO 3 -, (C 2 F 5 SO 2) 2 N -, (C 2 F 5 _{SO 2) (CF 3 SO 2} ) N - comprises at least one selected from a compound containing at least one anion selected from at least one selected from the group consisting of ^-, and _{(CF 3 SO 2) 2 N} .

Ionic liquids are specifically N- methyl -N- propyl blood roldi nium bis (trifluoromethane sulfonyl) imide [PYR13 ⁺ TFSI ^-], N- butyl -N- methylpyrrolidin Stadium bis (3-trifluoro Romero tilsul sulfonyl) imide {N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide [PYR14 + TFSI -]}, 1- butyl-3-methylimidazolium methyl sulfonyl as imidazolium bis (trifluoromethanesulfonyl) imide { 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide}[BMITFSI], 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

The electrolyte further includes an alkali metal salt or an alkaline earth metal salt. If the alkali metal salt or alkaline earth metal salt is further included as described above, the ionic conductivity of the electrolyte may be further improved. Here, examples of the alkali metal salt or alkaline earth metal salt include chloride, hydride, nitride, phosphide, sulfoamide, triflate, thiocyanate, perchlorate, borate or selenide containing an alkali metal or alkaline earth metal. have. Examples of the alkali metal or alkaline earth metal include lithium, sodium, potassium, barium, and calcium.

Examples of alkali metal salts include LiSCN, LiN(CN) ₂ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₃ C, LiN(SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) ₂ , LiPF ₃ (CF ₂ CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ (CF ₃ ) ₃ , LiB(C ₂ O ₄ ) ₂ , NaSCN, NaSO ₃ CF ₃ , KTFSI, NaTFSI, Ba(TFSI) ₂ , Pb(TFSI) ₂ , Ca(TFSI) ₂ and LiPF ₃ (CF ₂ CF ₃ ) ₃ One or more selected from among the can be mentioned.

When the electrolyte contains the ionic liquid and the lithium salt, the molar ratio of the ionic liquid/lithium ion (IL/Li) may be 0.1 to 2.0, for example 0.2 to 1.8, specifically 0.4 to 1.5. The electrolyte having such a molar ratio is excellent in lithium ion mobility and ionic conductivity, as well as excellent mechanical properties, so that the growth of lithium dendrites on the negative electrode surface can be effectively suppressed.

The weight average molecular weight of the polymer block containing the ion conductive repeating units constituting the ion conductive phase is 1,000 Daltons or more, for example 1,000 to 100,000 Daltons, specifically 5,000 to 50,000 Daltons. If a polymer block having such a weight average molecular weight range is provided, the block copolymer has an appropriate degree of polymerization, and thus an electrolyte with improved ionic conductivity can be obtained by using the block copolymer.

The weight average molecular weight of the polymer block constituting the structural phase is 1,000 Daltons or more, for example, 10,000 to 500,000 Daltons, specifically 15,000 to 400,000 Daltons. The content of the polymer block constituting the structural phase is 20 to 45 parts by weight, for example 22 to 43 parts by weight, specifically 25 to 40 parts by weight based on 100 parts by weight of the total weight of the block copolymer. If a polymer block having such a weight average molecular weight range is used, an electrolyte having excellent mechanical properties and ionic conductivity can be obtained.

The block copolymer according to an embodiment may be a linear or branched block copolymer. In addition, the form of the block copolymer may include a lamellar type, a cylindrical shape, or a gyroid type. Branched block copolymers include, for example, graft polymers, star-shaped polymers, comb polymers, brush polymers, and the like.

According to another embodiment, the ion jeondosang (conductive phase), and the structure is a block copolymer containing a double connection domain (co-continuous domain) comprising a (structural phase), the structure is i) one bifunctional polymerizable monomer, There is provided an electrolyte comprising a polymer which is a polymerization reaction product of ii) a polyfunctional polymerizable monomer and iii) an elastically retaining polymerizable monomer having a reactive functional group.

In the block copolymer constituting the above-described electrolyte, the size of the double-linked domain is 1 μm or more.

The electrolyte according to an exemplary embodiment has excellent elasticity so as to suppress the formation of dendrite of lithium metal while percolation of nanochannels capable of rapid movement of lithium ions is achieved. In addition, the mechanical properties of the electrolyte are improved, and when used in a secondary battery, the occurrence of cracks is suppressed, thereby effectively preventing an electric short inside the rechargeable battery.

Hereinafter, a method of manufacturing an electrolyte according to an embodiment will be described.

Electrolytes can be prepared, for example, according to the one-pot polymerization induced microphase separation (PIMS) method. By this method, crosslinking and/or grafting during the ionic conduction phase and structural phase separation phenomena occur. The phase is fixed by the reaction to form a double linked phase without domain boundaries throughout the structure.

A polymer for forming an ion conductive phase having a chain transfer agent at the terminal is mixed with a monomer for forming a structural polymer to obtain an electrolyte composition. The electrolyte can be obtained by carrying out a polymerization reaction of the electrolyte composition. Here, the polymer for forming ion conductivity can be considered as an ion conductive polymer.

One or more selected from ionic liquids, alkali metal salts and alkaline earth metal salts may be further added to the electrolyte composition. Alternatively, the electrolyte obtained through the polymerization reaction described above may be impregnated with at least one selected from an ionic liquid, an alkali metal salt, and an alkaline earth metal salt.

The electrolyte composition further includes at _{least one inorganic particle selected from SiO 2} , TiO ₂ , ZnO, Al ₂ O ₃ , BaTiO ₃ , silsesquioxane of a cage structure, and a metal-organic framework (MOF). Can be included. The content of the inorganic particles is 1 to 20 parts by weight, for example 1 to 15 parts by weight, based on 100 parts by weight of the total weight of the electrolyte.

An organic solvent may be further included in the electrolyte composition. Here, as the organic solvent, tetrahydrofuran, methyl ethyl ketone, acetonitrile, ethanol, N,N-dimethylformamide, acetonitrile, methylene chloride, or a mixture thereof may be used.

To the above-described electrolyte composition, a polymerization initiator is added to accelerate the reactivity of the polymerization reaction. As the polymerization initiator, azobisisobutyronitrile (AIBN) or the like is used. The content of the polymerization initiator is at a conventional level.

The electrolyte obtained according to the above-described process may be in any desired form, for example, a layer, film or sheet having a thickness of 10 to 200 μm, for example 10 to 100 μm, specifically 10 to 60 μm. It can be manufactured in (sheet) form. In order to prepare the electrolyte in the form of a sheet, film or membrane, known techniques such as spin coating, roll coating, curtain coating, extrusion, casting, screen printing, inkjet printing, etc. may be used.

For example, an electrolyte can be obtained by applying the above-described electrolyte composition on a substrate, evaporating a solvent to form a film on the substrate, and separating the film from the substrate.

The electrolyte has, for example, a solid state.

The polymer for forming an ion conductive phase having a chain transfer agent at the end reacts with an ion conductive polymer, which is a polymer for forming an ion conductive phase, with a chain transfer agent, and a residue derived from the chain transfer agent is bonded to one end of the ion conductive polymer, resulting in an asymmetric end capped (asymmetric end). capped) may be an ion conductive polymer. A method of reacting an ion conductive polymer with a chain transfer agent to obtain an ion conductive polymer having a chain transfer agent at the terminal can be obtained according to a method known in the art.

The structurally formed polymeric monomer includes i) a monofunctional polymerizable monomer, ii) a polyfunctional polymerizable monomer, and/or iii) a polymerizable monomer having a reactive functional group.

During the polymerization reaction, the chain transfer agent bonded to the ion conductive polymer is transferred to the polymer in structure. A chain transfer agent (aka RAFT (Reversible addition-fragmentation chain transfer agent)) is a material used in living radical polymerization that can control the molecular weight and molecular weight distribution desired for a polymer, and is the active point of the chain transfer reaction. It serves to transfer or promote chain transfer reactions.

As the polymerization reaction proceeds with a copolymerization reaction of a monofunctional polymerizable monomer, a polyfunctional polymerizable monomer, and a polymerizable monomer having a reactive functional group, a crosslinking reaction of the polyfunctional polymerizable monomer and a reactive functional group of the polymerizable monomer having a reactive functional group A crosslinking reaction and/or a graft reaction proceeds to form a polymer forming a structural phase. A block copolymer having a double-linked structure formed by inducing phase separation through the above-described copolymerization reaction and crosslinking reaction or the above-described copolymerization reaction and crosslinking reaction and/or graft reaction is obtained.

At least one selected from an ionic liquid, an alkali metal salt, and an alkaline earth metal salt may be further added to the electrolyte composition. Alternatively, at least one selected from an ionic liquid, an alkali metal salt and an alkaline earth metal salt may be further added to the electrolyte obtained by performing the polymerization reaction.

The chain transfer agent containing the ion-conducting polymer is prepared by reacting a chain transfer agent with at least one selected from the group consisting of polyether-based, polyacrylic, polymethacrylic, and polysiloxane-based.

The polymerization reaction, copolymerization reaction, and crosslinking reaction are performed by RAFT (reversible addition-fragmentation chain transfer) polymerization. The graft reaction can also be achieved by RAFT polymerization. This RAFT reaction can be carried out using a chain transfer agent. When the RAFT reaction is performed using a chain transfer agent as described above, a block copolymer having a small polydispersity and an extended chain length can be obtained. Therefore, in this block copolymer, the size of the double-linked domain is increased to 1 μm or more compared to the conventional case.

The chain transfer agent is a compound represented by the following formula (1a).

[Formula 1a]

In Formula 1a, L is a free radical leaving group, and R ₃ is a group that controls the C=S double bond reactivity and affects the rate of radical addition and fragmentation.

As an example of the L -CH ₂ CN, -C(CH ₃ ) ₂ CN, -C(CN)(CH ₃ )CH ₂ C(=O)OH, -C(CH ₃ ) ₂ CN, or -C( CH ₃ ) ₂ C(=O)OH. And _{examples of R 3} include a phenyl group, -SC ₁₂ H ₂₅ , or -N(CH ₃ )C ₆ H ₅ group.

As an example of a chain transfer agent, thiocarbonylthio compounds such as dithioesters, dithiocarbamates, trithiocarbonates, and xanthates are used, and specifically, the following One selected from the compounds represented by Formula 1b is used.

[Formula 1b]

The chain transfer agent containing the ion-conducting polymer may be, for example, a compound represented by the following formula (3).

[Formula 3]

In Formula 3, L ₁ is a group derived from L in Formula 1, for example -C(=O)-C(R ₁ )(R ₂ )- or -C(=O)-(CH ₂ ) _k -C(R ₁ )(R ₂ )- (k is an integer from 1 to 5). And _{examples of R 3} include a substituted or unsubstituted C ₁ to C ₂₀ alkyl group, a substituted or unsubstituted C ₂ to C ₂₀ alkenyl group, a substituted or unsubstituted C ₆ to C ₅₀ aryl group, a substituted or Unsubstituted C ₆ ~C ₅₀ heteroaryl group, substituted or unsubstituted C ₅ ~C ₃₄ saturated or unsaturated carbocyclic group, substituted or unsubstituted C ₅ ~C ₃₄ aromatic carbocyclic group, substituted or It is an unsubstituted C ₅ ~C ₃₄ heterocyclic group, a cyano group, a C ₁ ~C ₂₀ alkylthio group, a C ₁ ~C ₂₀ alkoxy group, or a C ₂ ~C ₂₀ dialkylamino group.

R ₃ is, for example, a phenyl group, -SC ₁₂ H ₂₅ , -C ₆ H ₅ or -N(CH ₃ )C ₆ H ₅ .

R ₁ and R ₂ are independently of each other hydrogen, a cyano group, a substituted or unsubstituted C ₁ to C ₂₀ alkyl group, a substituted or unsubstituted C ₂ to C ₂₀ alkenyl group, a substituted or unsubstituted C ₆ to C ₅₀ aryl group, substituted or unsubstituted C ₆ to C ₅₀ heteroaryl group, substituted or unsubstituted C ₅ to C ₃₄ saturated or unsaturated carbocyclic group, substituted or unsubstituted C ₅ to C ₃₄ aromatic a carbocyclic group, a substituted or unsubstituted C ₅ ~ C ₃₄ come heterocyclic group, C ₁ ~ C ₂₀ alkyl group, a C ₁ ~ C ₂₀ alkoxy group, or a C ₂ ~ C ₂₀ dialkylamino group.

L ₁ is specifically -C(=O) CH ₂ C(CN)(CH ₃ )- or -C(=O)C(CH ₃ ) _2-

The compound represented by Formula 3 may be, for example, a compound represented by the following Formula 3a.

[Formula 3a]

In Formula 3a, R ₁ to R ₃ are each independently hydrogen, a cyano group, or a substituted

Or an unsubstituted C ₁ ~C ₂₀ alkyl group, a substituted or unsubstituted C ₂ ~C ₂₀ alkenyl group, a substituted or unsubstituted C ₆ ~C ₅₀ aryl group, a substituted or unsubstituted C ₆ ~C ₅₀ Heteroaryl group, substituted or unsubstituted C ₅ to C ₃₄ saturated or unsaturated carbocyclic group, substituted or unsubstituted C ₅ to C ₃₄ aromatic carbocyclic group, substituted or unsubstituted C ₅ to C ₃₄ hetero A cyclic group, a C ₁ to C ₂₀ alkylthio group, a C ₁ to C ₂₀ alkoxy group, or a C ₂ to C ₂₀ dialkylamino group,

R is a substituted or unsubstituted C2-C10 alkylene,

n is a number of 3 to 5,000 as the degree of polymerization.

The chain transfer agent including the ion conducting phase is a compound represented by the following formula (4).

[Formula 4]

In Formula 4, n, L ₁ and Z are as defined in Formula 3.

Examples of the compound represented by Formula 4 include a polymer represented by Formula 4a below.

[Formula 4a]

In Formula 4a, n is a number of 2 to 5,000 as the degree of polymerization.

The weight average molecular weight of the chain transfer agent containing the polymer for forming the ion conductive phase is 300 to 28000 Daltons.

The temperature of the polymerization reaction varies depending on the type of starting material, but is carried out at, for example, 20 to 150°C, for example, 100 to 120°C.

The block copolymer obtained according to the above manufacturing method can obtain an electrolyte having excellent elasticity and excellent ionic conductivity and mechanical properties.

The electrolyte according to an embodiment includes i) a polymer which is a polymerization product of styrene, 1,4-divinylbenzene, and 1,6-hexadiene, and ii) a block copolymer of polyethylene oxide. The electrolyte according to another embodiment includes a block copolymer of i) a polymer which is a polymerization product of styrene, 1,4-divinylbenzene, and butyl acrylate, and ii) a polyethylene oxide.

A residue derived from a chain transfer agent is bonded to the end of the polymer included in the structure, and a linker derived from a chain transfer agent (a.k.a. Junk blocks) may exist.

The residue is -SC(=S)-R ₃ and the linker is -C(=O)-C(R ₁ )(R ₂ )- or -C(=O)-(CH ₂ ) _k -C(R ₁ )(R ₂ )- (k is an integer of 1 to 5), and R ₁ to R ₃ are each independently hydrogen, a cyano group, a substituted or unsubstituted C ₁ to C ₂₀ alkyl group, a substituted or unsubstituted C ₂ to C ₂₀ alkenyl group, substituted or unsubstituted C ₆ to C ₅₀ aryl group, substituted or unsubstituted C ₆ to C ₅₀ heteroaryl group, substituted or unsubstituted C ₅ to C ₃₄ saturated or Unsaturated carbocyclic group, substituted or unsubstituted C ₅ to C ₃₄ aromatic carbocyclic group, substituted or unsubstituted C ₅ to C ₃₄ heterocyclic group, C ₁ to C ₂₀ alkylthio group, C ₁ to C ₂₀ It is an alkoxy group or a C ₂ ~C ₂₀ dialkylamino group.

Examples of residues are -SC(=S)-C ₁₂ H ₂₅ , -SC(=S)-C ₆ H _{5 ,} or -SC(=S)-N(CH ₃ )C ₆ H ₅ , and the linker is an example For example -C(=O)-CH ₂ -, -C(=O)-C(CH ₃ ) ₂ -, -C(=O)-CH ₂ -C(CH ₃ ) ₂ -, -C(= O)-CH ₂ CH ₂ -C(CH ₃ ) ₂ -or -C(=O)-CH ₂ CH ₂ -C(CH ₃ )(CN)-.

The electrolyte may include a block copolymer represented by the following formula (1) or a block copolymer represented by the following formula (2).

[Formula 1]

In Formula 1, m and n represent the degree of polymerization, m is a number of 2 to 5,000, n is a number of 2 to 5,000, for example, a number of 5 to 1,000,

a, b, and c all represent a mole fraction, and are independently numbers of 0 to 1, and a, b, and c are selected so that their sum total is 1.

[Formula 2]

In Formula 2, m and n represent the degree of polymerization, m is a number of 2 to 5,000, n is a number of 2 to 5,000, for example, a number of 5 to 1,000,

a, b, and c all represent a mole fraction, and are independently numbers of 0 to 1, and a, b, and c are selected so that their sum total is 1.

As an example of the block copolymer represented by Formula 1, there is a block copolymer represented by Formula 1c below.

[Formula 1c]

In Formula 1c, m, n, a, b, and c are as defined in Formula 1.

As an example of the block copolymer represented by Chemical Formula 2, there is a block copolymer represented by Chemical Formula 2a.

[Formula 2a]

In Formula 2a, m, n, a, b, and c are as defined in Formula 2.

In Formula 1, Formula 1c, Formula 2, and Formula 2a, a is, for example, 0.15 to 0.5, for example 0.16665 to 0.44445, b is 0.05 to 0.3, for example 0.1111 to 0.2, and c is 0.2 to 0.7, For example, it is 0.4 to 0.6667.

The mixing ratio of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the polymerizable monomer having a reactive functional group is 4:1:4 (44.445:11.11:44.445), 1:1:4 (16.665:16.665:66.67), 2: 1:2 (40:20:40) or 2:1:4 (28.57:14.29:57.14) molar ratio.

According to one embodiment, the elastic modulus of the electrolyte at room temperature (25° C.) is 4.0 MPa or more, for example, 4.0 to 1200 MPa, which is very good. And the tensile strength (Tensile strength) is 0.01 MPa or more, for example, 0.1 to 20 MPa at 25 ℃. In this way, the electrolyte can simultaneously secure mechanical properties required for battery performance even at room temperature.

The electrolyte _{further includes at least one inorganic particle selected from SiO 2} , TiO ₂ , ZnO, Al ₂ O ₃ , BaTiO ₃ , silsesquioxane of a cage structure, and a metal-organic framework (MOF). can do. If the inorganic particles are further included, mechanical properties of the electrolyte may be improved.

The average particle diameter of the inorganic particles is less than 100 nm, for example, 1 nm to 100 nm. The average particle diameter of the inorganic particles may be 5nm to 100nm, for example 10nm to 100nm, specifically 10nm to 70nm or 30nm to 70nm. When the particle diameter of the inorganic particles is within the above range, an electrolyte having excellent film-forming properties and excellent mechanical properties can be prepared without deteriorating ionic conductivity.

The metal-organic skeletal structure is a porous crystalline compound in which metal ions of groups 12 to 15 or metal ion clusters of groups 12 to 15 are formed by chemical bonds with organic ligands.

The organic ligand refers to an organic group capable of chemical bonds such as coordination bonds, ionic bonds, or covalent bonds. For example, an organic group having two or more sites capable of bonding with the aforementioned metal ions is stable by bonding with metal ions. Can form a structure.

The Group 2 to Group 15 metal ions are cobalt (Co), nickel (Ni), molybdenum (Mo), tungsten (W), ruthenium (Ru), osdium (Os), cadmium (Cd), beryllium (Be), Calcium (Ca), barium (Ba), strontium (Sr), iron (Fe), manganese (Mn), chromium (Cr), vanadium (V), aluminum (Al), titanium (Ti), zirconium (Zr) ), copper (Cu), zinc (Zn), magnesium (Mg), hafnium (Hf), Nb, tantalum (Ta), Re, rhodium (Rh), iridium (Ir), palladium (Pd), platinum (Pt) , Silver (Ag), scandium (Sc), yttrium (Y), indium (In), thallium (Tl), silicon (Si), Ge, tin (Sn), lead (Pb), arsenic (As), antimony ( Sb) and at least one selected from bismuth (Bi), and the organic ligand is an aromatic dicarboxylic acid, an aromatic tricarboxylic acid, an imidazole-based compound, a tetrazole-based, 1,2,3-triazole, 1,2, 4-triazole, pyrazole, aromatic sulfonic acid, aromatic phosphoric acid, aromatic sulfinic acid, aromatic phosphinic acid, bipyridine, amino group, imino group, amide group, methane a group, a pyridine group, a group derived from at least one selected from a compound having at least one functional group selected from the group ^{pyrazin-dithiol} Osan (-CS ₂ H) group, a methane dithiol Osan anion (-CS _2).

Examples of the above-described aromatic dicarboxylic acid and aromatic tricarboxylic acid include benzenedicarboxylic acid, benzenetricarboxylic acid, biphenyldicarboxylic acid or triphenyldicarboxylic acid.

The organic ligand described above may specifically be a group derived from a compound represented by the following formula 4b.

[Formula 4b]

The metal-organic framework is, for example, Ti ₈ O ₈ (OH) ₄ [O ₂ CC ₆ H ₄ C0 ₂ ] _{6 ,} Cu(bpy)(H ₂ O) ₂ (BF4),(bpy)(bpy=4 , 4'-bipyridine) or Zn ₄ O(O ₂ CC ₆ H ₄ -CO ₂ ) ₃ (Zn-terephthalic acid-MOF, Zn-MOF).

The electrolyte according to an embodiment may also be used as a protective film to protect the negative electrode. In this case, when the electrolyte is used as a protective film, an electrolyte may be additionally included. In this case, the electrolyte may be interposed between the anode and the electrolyte used as the above-described protective film according to an embodiment.

The electrolyte is at least one selected from a liquid electrolyte, a solid electrolyte, a gel electrolyte, a polymer ionic liquid, and a separator.

According to another aspect, a secondary battery including an electrolyte according to an embodiment is provided. The secondary battery has a structure in which a positive electrode, an electrolyte, and a negative electrode are stacked.

In addition to the secondary battery, the above-described electrolyte can be applied to a charge transport layer of a light emitting diode, an energy storage device such as a supercapacitor, and the like.

In the secondary battery, at least one selected from a liquid electrolyte, a polymer ionic liquid, a solid electrolyte, and a gel electrolyte may be further included. At least one selected from a liquid electrolyte, a polymer ionic liquid, a gel electrolyte, and an electrolyte may be interposed between the positive electrode and the electrolyte.

As described above, if at least one selected from a liquid electrolyte, a polymer ionic liquid, a solid electrolyte, and a gel electrolyte is further included, the ionic conductivity and mechanical properties of the battery may be further improved.

The liquid electrolyte further includes at least one selected from an organic solvent, an ionic liquid, an alkali metal salt, and an alkaline earth metal salt.

The organic solvent includes a carbonate-based compound, a glyme-based compound, and a dioxolane-based compound. Carbonate-based compounds include ethylene carbonate, propylene carbonate, dimethyl carbonate, fluoroethylene carbonate, diethyl carbonate, or ethylmethyl carbonate. And glyme compounds are poly(ethylene glycol) dimethyl ether; PEGDME, polyglyme, tetra(ethylene glycol) dimethyl ether; TEGDME, tetraglyme), tri(ethylene glycol) dimethyl ether Glycol) dimethyl ether (tri(ethylene glycol) dimethyl ether, triglyme), poly(ethylene glycol) dilaurate (PEGDL), poly(ethylene glycol) monoacrylate ; PEGMA), and poly(ethylene glycol) diacrylate (poly(ethylene glycol) diacrylate; PEGDA).

Examples of dioxolane compounds include 3-dioxolane, 4,5-diethyl-dioxolane, 4,5-dimethyl-dioxolane, 4-methyl-1,3-dioxolane, and 4-ethyl There is at least one selected from the group consisting of -1,3-dioxolane.

As the organic solvent, 2,2-dimethoxy-2-phenylacetophenone, dimethoxyethane, diethoxyethane, tetrahydrofuran, gamma butyrolactone, trimethyl phosphate, and the like may be used.

As the polymeric ionic liquid, a polymer obtained by polymerizing an ionic liquid monomer may be used, and a compound obtained in a polymeric form may be used. These polymeric ionic liquids have high solubility in organic solvents and have the advantage of further improving ionic conductivity when added to an electrolyte.

In the case of polymerizing the above-described ionic liquid monomer to obtain a polymeric ionic liquid, the resultant of the polymerization reaction is washed and dried, and then prepared to have an appropriate anion capable of imparting solubility in an organic solvent through anion substitution reaction. do. Polymeric ionic liquids according to one embodiment are i) ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphor nyumgye, sulfo nyumgye, triazole one or more cations selected from the sol ryumgye, and mixtures thereof, ^{_{and, ii) BF 4 -, PF}} 6 -, AsF 6 -, SbF 6 -, AlCl 4 -, HSO 4 -, ClO 4 -, CH 3 _{^{SO 3 -, CF 3 CO 2}} -, Cl -, Br -, I -, SO 4 -, CF 3 SO 3 -, (C 2 F 5 SO 2) 2 N -, (C 2 F 5 SO 2) ( ^{_{CF 3 SO 2) N -,}} NO 3 -, Al 2 Cl 7 -, CH 3 COO -, (CF 3 SO 2) 3 C -, (CF 3 CF 2 SO 2) 2 N -, (CF 3) 2 _{^{PF 4 -, (CF 3)}} 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, SF 5 CF 2 SO 3 -, SF 5 CHFCF 2 _{^{SO 3 -, CF 3 CF 2}} (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, (O (CF 3) 2 C 2 (CF 3) 2 O) ₂ PO ^- and (CF ₃ SO ₂ ) ₂ N ^- may contain a repeating unit including at least one anion selected from.

According to another embodiment, the polymeric ionic liquid may be prepared by polymerizing an ionic liquid monomer. The ionic liquid monomer is an ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based monomer having a polymerizable functional group such as a vinyl group, allyl group, acrylate group, methacrylate group, etc. , Pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, triazolium-based, and a mixture thereof, and at least one cation selected from among the above-described anions.

Examples of the ionic liquid monomer include 1-vinyl-3-ethylimidazolium bromide, and a compound represented by the following formula (5) or (6).

[Formula 5]

[Formula 6]

Examples of the above-described polymeric ionic liquid include a compound represented by the following formula (7) or a compound represented by formula (8).

[Formula 7]

In Formula 7, R ₁ and R ₃ are each the same or different, and each represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms, and may optionally include one or more heteroatoms. In Formula 7, R ₂ represents a chemical bond or a group containing 1 to 16 carbon atoms, and may optionally include one or more hetero atoms. In addition, X ^- represents an anion of an ionic liquid.

The polymeric ionic liquid represented by Chemical Formula 7 is poly(1-vinyl-3-alkylimidazolium), poly(1-allyl-3-alkylimidazolium), poly(1-( selected from the group consisting of methacrylic ilrok-3-alkyl imidazolium) a cation ^{_{and, CH 3 COO -, CF 3}} COO -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, _{(CF 3 SO 2) 3 C} -, (CF 3 CF 2 SO 2) 2 N -, C 4 F 9 SO 3 -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 CO) N - It contains an anion selected from among.

[Formula 8]

In the formula 8 ^Y-X is in formula (7) ^- is defined in the same manner as, for example, bis (trifluoromethanesulfonyl) imide (TFSI) , BF 4, or CF ₃ SO _3, n is from 500 to 2800.

The compound represented by Formula 8 may include polydiallyldimethylammonium bis(trifluoromethanesulfonyl)imide.

According to another embodiment, the polymer ionic liquid may include a low molecular weight polymer, a thermally stable ionic liquid, and a lithium salt. The low molecular weight polymer may have an ethylene oxide chain. The low molecular weight polymer may be glyme. Here, the glyme is, for example, polyethylene glycol dimethyl ether (polyglyme), tetraethylene glycol dimethyl ether (tetraglyme), and triethylene glycol dimethyl ether (triglyme).

The weight average molecular weight of the low molecular weight polymer is 75 to 2000, for example 250 to 500. And the thermally stable ionic liquid is as defined in the above-described ionic liquid. As for the lithium salt, all of the compounds in which the alkali metal is lithium among the above-described alkali metal salts can be used.

If the gel electrolyte is further included, the conductivity may be further improved.

The gel electrolyte is an electrolyte having a gel form and can be used as long as it is well known in the art.

The gel electrolyte may contain, for example, a polymer and a polymer ionic liquid.

The polymer may be, for example, a solid graft (block) copolymer electrolyte.

The solid electrolyte may be an organic solid electrolyte or an inorganic solid electrolyte.

The above-described gel electrolyte and solid electrolyte may have a sheet or film or layer form.

Examples of the organic solid electrolyte include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphoric acid ester polymers, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociation groups, etc. Can be used.

The inorganic solid _{electrolyte, Cu 3 N, Li 3 N} , LiPON, Li 3 PO 4 .Li 2 S.SiS 2, Li 2 S.GeS 2 .Ga 2 S 3, (Na, Li) 1 + x Ti _2-x Al _x (PO ₄ ) ₃ (0.1≤x≤0.9), Li _{1 + x} Hf _{2 - x} Al _x (PO ₄ ) ₃ (0.1≤x≤0.9), Na ₃ Zr ₂ Si ₂ PO ₁₂ , Li ₃ Zr ₂ Si ₂ PO ₁₂ , Na ₅ ZrP ₃ O ₁₂ , Na ₅ TiP ₃ O ₁₂ , Na ₃ Fe ₂ P ₃ O ₁₂ , Na ₄ NbP ₃ O ₁₂ , NLi _0.3 La _0.5 TiO ₃ , Na ₅ MSi ₄ O ₁₂ (M is a rare earth element such as Nd, Gd, Dy, etc.) Li ₅ ZrP ₃ O ₁₂ , Li ₅ TiP ₃ O ₁₂ , Li ₃ Fe ₂ P ₃ O ₁₂ , Li ₄ NbP ₃ O ₁₂ , Li _{1 + x} (M, Al,Ga) _x (Ge _1-y Ti _y ) _{2 -x} (PO ₄ ) ₃ (0≤X≤0.8, 0≤Y≤1.0, M is Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb), Li _{1 +x+ y} Q _x Ti _{2 - x} Si _y P _{3 - y} O ₁₂ (0<x≤0.4, 0<y≤0.6, Q is Al or Ga), Li ₆ BaLa ₂ Ta ₂ O ₁₂ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₅ La ₃ Nb ₂ O ₁₂ , Li ₅ La ₃ M ₂ O ₁₂ (M is Nb, Ta), Li _7+x A _x La _3-x Zr ₂ O ₁₂ (0<x<3, A is Zn), etc. may be used.

As the separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used, and a polyethylene/polypropylene two-layer separator, a polyethylene/polypropylene/polyethylene three-layer separator, a polypropylene/ A mixed multilayer film such as a polyethylene/polypropylene three-layer separator or the like may be used.

The electrolyte according to an embodiment may have a solid or gel form. And the thickness of the electrolyte is 200㎛ or less, for example, 10 to 200㎛, for example 10 to 100㎛, specifically, it can be produced in the form of a film, film or sheet having a thickness of 10 to 60㎛. In order to prepare the electrolyte in the form of a sheet, film or membrane, known techniques such as spin coating, roll coating, curtain coating, extrusion, casting, screen printing, inkjet printing, etc. may be used.

The electrolyte according to an embodiment may have a solid phase. And the thickness of the electrolyte is 100 μm or less, for example, 30 to 60 μm.

The ionic conductivity of the electrolyte is 1 X 10 ^-4 S/cm or more at 25° C., for example, 1 X

10 ^-4 S to 1 X 10 ^-3 SS/cm. And the elastic modulus (Young's modulus) of the electrolyte is 4.0 MPa or more, for example, 10 to 2000 MPa at 25°C. The electrolyte can simultaneously secure ionic conductivity and mechanical properties required for battery performance even at room temperature.

The electrolyte may further include at least one selected from a liquid electrolyte, a solid electrolyte, a gel electrolyte, a polymer ionic liquid, and a separator. As such, the electrolyte may be a mixed electrolyte type.

A secondary battery according to an embodiment includes, for example, a lithium battery, a lithium air battery, a lithium sulfur battery, a sodium lithium battery, and a magnesium lithium battery.

Magnesium lithium batteries use magnesium metal, which is relatively inexpensive and exists in a large amount, instead of lithium, which is a rare metal, as a negative electrode, and magnesium ions are inserted and desorbed into the positive electrode active material to allow charging and discharging. It is more than double, inexpensive and stable in the atmosphere And because it is environmentally friendly, has excellent price competitiveness, and has high energy storage characteristics, it is useful as a medium and large-sized battery, such as for power storage and electric vehicles, and is drawing attention as a next-generation secondary battery. In addition, the sodium lithium battery has a positive electrode capable of doping and undoping sodium ions, and a negative electrode capable of doping and undoping sodium ions.

Lithium batteries are widely used in fields such as mobile phones, notebook computers, storage batteries of power generation facilities such as wind power and solar power, electric vehicles, uninterruptible power supplies, and home storage batteries due to their high voltage, capacity, and energy density.

In the lithium battery, at least one selected from a liquid electrolyte, a polymer ionic liquid, a solid electrolyte, and a gel electrolyte may be further included. At least one selected from a liquid electrolyte, a polymer ionic liquid, a gel electrolyte, and an electrolyte may be interposed between the positive electrode and the electrolyte.

1A to 1D schematically show the structure of a lithium battery including an electrolyte according to an embodiment.

As shown in FIG. 1A, the lithium battery has a structure in which an electrolyte 23 according to an embodiment is interposed between a positive electrode 21 and a negative electrode 22.

As shown in FIG. 1B, an intermediate layer 24 may be further included between the electrolyte 23 and the anode 21. The intermediate layer 24 has a composition different from that of the electrolyte 23 and may further include at least one selected from a liquid electrolyte, a polymer ionic liquid, a solid electrolyte, and a gel electrolyte.

As the above-described electrolyte 23 is disposed on at least a portion of the negative electrode 22, the surface of the negative electrode may be mechanically stabilized and thus electrochemically stabilized. Therefore, it is possible to suppress the formation of dendrites due to ion unevenness on the negative electrode surface during charging and discharging of the lithium battery, and the interfacial stability between the negative electrode and the electrolyte is improved. Therefore, the cycle characteristics of the lithium battery can be improved.

The electrolyte may serve as a protective film to protect the negative electrode surface by completely covering the negative electrode surface. For example, it is possible to prevent the negative electrode from directly contacting the surface of the negative electrode disposed between the electrolyte and the positive electrode and the highly reactive electrolyte. Therefore, it is possible to increase the stability of the negative electrode by protecting the negative electrode.

As shown in FIG. 1C, the intermediate layer 24 may have a two-layer structure in which a liquid electrolyte 24a and a solid electrolyte 24b are sequentially stacked. Here, the liquid electrolyte may be disposed adjacent to the electrolyte 23. Such a lithium battery has a lamination order of a negative electrode/electrolyte/intermediate layer (liquid electrolyte/solid electrolyte)/anode.

Referring to FIG. 1D, the lithium battery according to the exemplary embodiment may use a separator 24c as an intermediate layer. As the separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used, and a polyethylene/polypropylene two-layer separator, a polyethylene/polypropylene/polyethylene three-layer separator, a polypropylene/ A mixed multilayer film such as a polyethylene/polypropylene three-layer separator or the like may be used.

As shown in FIG. 1B, a liquid electrolyte 24a may be disposed as an intermediate layer of a lithium battery according to an embodiment. Here, the liquid electrolyte may be the same as or different from the composition of the liquid electrolyte that may be contained in the electrolyte 23.

1A to 1E, the anode may be a porous anode. The porous anode also includes an anode in which a liquid electrolyte may penetrate into the anode by capillary phenomenon or the like because the porous anode contains pores or does not intentionally exclude the formation of the anode.

For example, the porous positive electrode includes a positive electrode obtained by coating and drying a positive electrode active material composition including a positive electrode active material, a conductive agent, a binder, and a solvent. The positive electrode thus obtained may contain pores existing between particles of the positive electrode active material. A liquid electrolyte may be impregnated into such a porous anode.

According to another embodiment, the positive electrode may include a liquid electrolyte, a gel electrolyte, and a solid electrolyte. The liquid electrolyte, gel electrolyte, and solid electrolyte can be used as electrolytes for lithium batteries in the art, as long as they do not deteriorate the positive electrode active material by reacting with the positive electrode active material during the charging and discharging process.

In FIGS. 1A to 1E, a lithium metal thin film may be used as a negative electrode. The thickness of the lithium metal thin film may be less than 100 μm. For example, the lithium battery may have stable cycle characteristics even for a lithium metal thin film having a thickness of less than 100 μm. For example, in the lithium battery, the thickness of the lithium metal thin film may be 80 μm or less, for example, 60 μm or less, and specifically 0.1 to 60 μm. In the conventional lithium battery, when the thickness of the lithium metal thin film is reduced to less than 100 μm, the thickness of lithium deteriorated by side reactions and dendrite formation increases, making it difficult to implement a lithium battery providing stable cycle characteristics. However, if the electrolyte according to an embodiment is used, a lithium battery having stable cycle characteristics can be manufactured.

1F shows a structure of a lithium battery including an electrolyte according to another embodiment.

Referring to this, it includes an anode 11, a cathode 12, and an electrolyte 13. The positive electrode 11, the negative electrode 12, and the electrolyte 13 according to an embodiment described above are wound or folded to be accommodated in the battery case 15. Subsequently, an electrolyte solution is injected into the battery case 15 and sealed with a cap assembly 16 to complete the ion lithium battery 11. The battery case may be a cylindrical shape, a square shape, or a thin film type. For example, the lithium battery may be a large thin-film battery. The lithium battery may be an ion lithium battery.

A separator may be disposed between the positive electrode and the negative electrode to form a battery structure. After the battery structure is stacked in a bi-cell structure, it is impregnated with an electrolyte, and the resulting product is accommodated in a pouch and sealed, thereby completing a lithium polymer battery.

A plurality of the electrical structures are stacked to form a battery pack. These battery packs can be used in all devices requiring high capacity. For example, it can be used for laptops, smartphones, and electric vehicles.

The lithium battery is, for example, a lithium battery.

According to another aspect, there is provided a lithium battery comprising a positive electrode, a negative electrode, and the above-described electrolyte interposed therebetween, wherein the negative electrode is a lithium metal or lithium metal alloy electrode. Here, the lithium battery may be a lithium metal battery. As such, the negative electrode is a lithium metal or lithium alloy electrode, and at least one additional layer selected from a liquid electrolyte, a gel electrolyte, a solid electrolyte, a separator, and a polymer ionic liquid may be further included between the electrolyte and the positive electrode.

An at least partially formed sheet or film may be included on one surface of the anode or cathode.

The electrolyte may serve as a protective film for a lithium metal or lithium metal alloy electrode. When such an electrolyte is stacked on the negative electrode, it is possible to suppress the growth of lithium dendrite on the surface of the negative electrode after charging and discharging, and the effect of suppressing the occurrence of a short circuit inside the battery due to the occurrence of cracks in the electrolyte is very excellent.

The lithium battery according to an embodiment may have an operating voltage of 4.0 to 5.0V, for example, 4.5 to 5.0V.

Each component constituting a lithium battery including an electrolyte according to an exemplary embodiment and a method of manufacturing a lithium battery having such a component will be described in more detail as follows.

As a positive electrode active material for manufacturing a positive electrode, it may include at least one selected from the group consisting of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide, but is not limited thereto. Also, any positive electrode active material available in the art may be used.

For _{example, Li a A 1 - b B} b D 2 ( in the above formula, 0.90≤a≤1.8, and 0≤b≤0.5); Li _a E _1-b B _b O _2-c D _c (in the above formula, 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); _{LiE 2 - b B b O 4} -c D c ( wherein, 0≤b≤0.5, 0≤c≤0.05 a); Li _a Ni _{1 -b- c} Co _b B _c D _α (in the above formula, 0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05, 0<α≦2); _{Li a Ni 1 -b- c Co b} B c O 2 - α F α ( wherein, 0.90≤a≤1.8, 0≤b≤0.5, is 0≤c≤0.05, 0 <α <2) ; _{Li a Ni 1 -b- c Co b} B c O 2 - α F α ( wherein, 0.90≤a≤1.8, 0≤b≤0.5, is 0≤c≤0.05, 0 <α <2) ; Li _a Ni _{1 -b- c} Mn _b B _c D _α (in the above formula, 0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05, 0<α≦2); _{Li a Ni 1 -b- c Mn b} B c O 2 - α F α ( wherein, 0.90≤a≤1.8, 0≤b≤0.5, is 0≤c≤0.05, 0 <α <2) ; Li _a Ni _{1 -bc} Mn _b B _c O _2-α F _α (in the above formula, 0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05, 0<α<2); Li _a Ni _b E _c G _d O ₂ (In the above formula, 0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5, and 0.001≦d≦0.1); Li _a Ni _b Co _c Mn _d GeO ₂ (In the above formula, 0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5, 0≦d≦0.5, and 0.001≦e≦0.1); Li _{a NiG b} O ₂ (in the above formula, 0.90≦a≦1.8 and 0.001≦b≦0.1); Li _a CoG _b O ₂ (in the above formula, 0.90≦a≦1.8 and 0.001≦b≦0.1); Li _{a MnG b} O ₂ (in the above formula, 0.90≦a≦1.8 and 0.001≦b≦0.1); Li _a Mn ₂ G _b O ₄ (In the above formula, 0.90≦a≦1.8 and 0.001≦b≦0.1); QO ₂ ; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiIO ₂ ; LiNiVO ₄ ; Li _(3-f) J ₂ (PO ₄ ) ₃ (0≦f≦2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0≦f≦2); A compound represented by any one of the formulas of LiFePO _{4 may be used.}

In the above formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or combinations thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

The cathode active material may be, for example, a compound represented by Formula 9, a compound represented by Formula 10, or a compound represented by Formula 11.

[Formula 9]

Li _a Ni _b Co _c Mn _d O ₂

In Formula 9, 0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5, and 0≦d≦0.5.

[Formula 10]

Li ₂ MnO ₃

[Formula 11]

LiMO ₂

In Formula 11, M is Mn, Fe, Co, or Ni.

A positive electrode is prepared according to the following method.

A positive electrode active material composition in which a positive electrode active material, a binder, and a solvent are mixed is prepared.

A conductive agent may be further added to the positive electrode active material composition. The positive electrode active material composition is directly coated and dried on a metal current collector to prepare a positive electrode plate. Alternatively, the positive electrode active material composition may be cast on a separate support, and then a film peeled from the support may be laminated on a metal current collector to prepare a positive electrode plate.

In the positive electrode active material composition, a conductive agent, a binder, and a solvent may be the same as those of the negative electrode active material composition. Meanwhile, it is also possible to form pores in the electrode plate by further adding a plasticizer to the positive electrode active material composition and/or the negative electrode active material composition. The contents of the positive electrode active material, the conductive agent, the binder, and the solvent are the levels commonly used in lithium batteries. One or more of the conductive agent, binder, and solvent may be omitted depending on the use and configuration of the lithium battery.

The negative electrode can be obtained by carrying out almost the same method except that the negative active material is used instead of the positive active material in the above-described positive electrode manufacturing process.

As the negative electrode active material, a carbon-based material, silicon, silicon oxide, silicon-based alloy, silicon-carbon-based material composite, tin, tin-based alloy, tin-carbon composite, metal oxide, or a combination thereof is used. The carbon-based material may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as amorphous, plate, flake, spherical or fibrous natural graphite or artificial graphite, and the amorphous carbon is soft carbon (low temperature calcined carbon) or hard carbon (hard carbon). carbon), mesophase pitch carbide, calcined coke, graphene, carbon black, fullerene soot, carbon nanotubes, carbon fibers, etc. Anything that can be used is possible.

The negative active material may be selected from the group consisting of Si, SiOx (0 <x <2, for example 0.5 to 1.5), Sn, SnO ₂ , or silicon-containing metal alloys and mixtures thereof. As the metal capable of forming the silicon alloy, one or more of Al, Sn, Ag, Fe, Bi, Mg, Zn, in, Ge, Pb, and Ti may be used.

The negative active material may include a metal/metalloid alloyable with lithium, an alloy thereof, or an oxide thereof. For example, the metal/metalloid alloyable with lithium is Si, Sn, Al, Ge, Pb, Bi, SbSi-Y alloy (wherein Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal , A rare earth element or a combination element thereof, not Si), Sn-Y alloy (the Y is an alkali metal, an alkaline earth metal, a group 13 element, a group 14 element, a transition metal, a rare earth element, or a combination element thereof, and Sn Is not), MnOx (0 <x ≤ 2), and the like. The element Y is 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, Ti, Ge, P, As, Sb, Bi, S, It may be Se, Te, Po, or a combination thereof. For example, the oxide of the metal/metalloid that can be alloyed with lithium may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, SnO ₂ , SiO _x (0<x<2), and the like.

For example, a lithium negative electrode thin film may be used as the negative electrode.

The contents of the negative electrode active material, the conductive agent, the binder, and the solvent are the levels commonly used in lithium batteries.

As an electrolyte, an electrolyte according to an embodiment is used.

In addition to the above-described electrolyte, a separator commonly used in lithium batteries and/or a lithium salt-containing non-aqueous electrolyte may be further provided.

As the separator, an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 　0.01 to 10 µm, and the thickness is generally 5 to 20 µm. Examples of such a separator include olefin-based polymers such as polypropylene; Sheets or non-woven fabrics made of glass fiber or polyethylene are used. When a solid electrolyte is used as the electrolyte, the solid electrolyte may also serve as a separator.

Among the separators, specific examples of the olefin-based polymer include polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film having two or more layers thereof, and a polyethylene/polypropylene two-layer separator, polyethylene/polypropylene/polyethylene. A mixed multilayer film such as a three-layer separator, a polypropylene/polyethylene/polypropylene three-layer separator, and the like may be used.

The lithium salt-containing non-aqueous electrolyte is composed of a non-aqueous electrolyte and a lithium salt.

As the non-aqueous electrolyte, a non-aqueous electrolyte, an organic solid electrolyte, or an inorganic solid electrolyte is used.

The non-aqueous electrolyte solution contains an organic solvent. Any such organic solvent may be used as long as it can be used as an organic solvent in the art. For example, propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate , Fluoroethylene carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, N, N-dimethylacetamide, N,N-dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or mixtures thereof.

Examples of the lithium salt include, for example, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiAlO ₂ , LiAlCl ₄ , LiN(C _x F _{2x + 1} SO 2 )(C _y F _{2y + 1} SO ₂ ) (where x and y are natural numbers), LiCl, LiI, or mixtures thereof.

The lithium battery according to one embodiment has excellent life characteristics and can be used not only for battery cells used as power sources for small devices, but also for medium and large battery packs or battery modules including a plurality of battery cells used as power sources for medium and large devices. It can also be used as a unit cell.

Examples of the medium and large-sized devices include electric vehicle electric bicycles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc. E-bike), an electric two-wheeled vehicle power tool power storage device including an electric scooter (E-scooter), and the like, but are not limited thereto. It will be described in more detail through the following examples and comparative examples. However, the examples are for illustrative purposes and are not limited thereto.

Example 1: Preparation of electrolyte (S:DVB:1,6-HD=4:1:4 molar ratio)

PEO-CTA represented by the following formula (12) (weight average molecular weight: 10 ⁴ Daltons, polydispersity (Mw/Mn): about 1.11), styrene (hereinafter referred to as S), 1,4-divinylbenzene (hereinafter referred to as DVB) and 1,6-hexadiene ( 1,6-hexadiene (hereinafter referred to as 1,6-HD) was mixed to obtain a monomer mixture. Here, the content of PEO-CTA in the monomer mixture was about 35% by weight, and the mixing ratio of styrene, 1,4-divinylbenzene and 1,6-hexadiene was 4:1:4 molar ratio.

[Formula 12]

PEO-CTA

In Formula 12, n was adjusted so that the weight average molecular weight of the polymer represented by Formula 12 was about 10 ^{4 Daltons.}

N-methyl-N-propyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide) as an ionic liquid in the monomer mixture (PYR13+) TFSI-], bis(trifluoromethylsulfonyl)imide (LiTFSI), which is a lithium salt, and polyethylene glycol dimethyl ether (PEGDME) (weight average molecular weight: about 250 Dalton) were added and mixed to obtain an electrolyte composition. In the composition, the content of PEO-CTA is 35% by volume, the total content of monomers (styrene + 1,4-divinylbenzene + 1,6-hexadiene) is about 55% by volume, and the total content of ionic liquid and lithium salt is 10. It was volume %.

The mixing ratio of the ionic liquid and the lithium salt was 3:1 molar ratio, and the mixing ratio of the ionic liquid and PEGDME was 80:20 by volume.

AIBN (Azobisisobutyronitrile), which is a radical initiator, is added to the electrolyte composition, coated on a support substrate using a doctor blade, and then subjected to a polymerization reaction by heat treatment at about 110° C. for 12 hours to form a block copolymer represented by the following formula (1c). An electrolyte consisting of the coalescence {PEO-b-(S-co-DVB-co-HD)} was obtained. The content of AIBN was about 0.05 mol based on 1 mol of PEO-CTA.

[Formula 1c]

In Formula 1c, m and n represent the degree of polymerization, n is the weight average molecular weight of the ion conductive block (PEO block) was ^{controlled to be about 10 4} Daltons, and m is the weight average molecular weight of the block copolymer represented by Formula 1c. It was controlled to be about 56,000 Daltons.

All of a, b, and c represent the mole fraction, the sum of which is 1, a is about 0.44445, b is about 0.1111, and c is about 0.44445. Thus, the ratio of a, b and c was 4:1:4.

Example 2: Preparation of electrolyte (S:DVB:BA=2:1:2 molar ratio)

When preparing the monomer mixture, n-butyl acrylate was used instead of 1,6-hexadiene.

Except that the mixing molar ratio of styrene, 1,4-divinylbenzene and n-butyl acrylate (hereinafter referred to as BA) is 2:1:2 (styrene:DVB:BA=2:1:2 molar ratio) Then, in the same manner as in Example 1, an electrolyte composed of a block copolymer {PEO-b-(S-co-DVB-co-BA)} represented by the following formula 2a was obtained.

[Formula 2a]

In Formula 2a, n was controlled so that the weight average molecular weight of the ion conductive block (PEO block) was about 10 ⁴ Daltons, and m was controlled so that the weight average molecular weight of the block copolymer represented by Formula 2a was about 56,000 Daltons. a, b, and c all represent the mole fraction, the sum of which is 1, a is about 0.4, b is about 0.2, and c is about 0.4.

Example 3: Preparation of electrolyte (S:DVB:BA=2:1:4 molar ratio)

When preparing the monomer mixture, n-butyl acrylate was used instead of 1,6-hexadiene.

Block represented by the following formula 2a by carrying out in the same manner as in Example 1, except that the mixing molar ratio of styrene, 1,4-divinylbenzene and n-butyl acrylate (BA) is 2:1:4. An electrolyte consisting of a copolymer {PEO-b-(S-co-DVB-co-BA)} was obtained.

[Formula 2a]

In Formula 2a, n was controlled so that the weight average molecular weight of the ion conductive block (PEO block) was about 10 ⁴ Daltons, and m was controlled so that the weight average molecular weight of the block copolymer represented by Formula 2a was about 56,000 Daltons.

a, b, and c all represent the mole fraction, the sum of which is 1, a is about 0.2857, b is about 0.1429, and c is about 0.5714. Thus, the ratio of a, b and c was 2:1:4.

Example 4: Preparation of electrolyte (S:DVB:1,6-HD=4:1:4 molar ratio)

The weight average molecular weight of PEO-CTA represented by Chemical Formula 12 was changed ^{to 10 3 Daltons.}

Except that, it was carried out in the same manner as in Example 1 to obtain an electrolyte.

Example 5: Preparation of electrolyte (S:DVB:1,4-HD=4:1:4 molar ratio

When preparing a monomer mixture, 1,4-butadiene (1,4-hexadiene:

(Hereinafter referred to as 1,4-HD), except for using, was carried out in the same manner as in Example 1 to obtain an electrolyte.

Example 6: Preparation of electrolyte

Except for using 4,4"-divinyl-5'-(4-vinylphenyl)-1,1': 3',1"-terphenyl instead of 1,4-divinylbenzene when preparing the monomer mixture, It carried out in the same manner as in Example 1 to obtain an electrolyte.

Example 7: Preparation of electrolyte

When preparing the monomer mixture, a compound represented by the following formula 10a was used instead of 1,6-hexadiene.

Except, it was carried out in the same manner as in Example 1 to obtain an electrolyte.

[Formula 10a]

Example 8: Preparation of electrolyte (S:DVB:BA=1:1:4 molar ratio)

When preparing the monomer mixture, n-butyl acrylate was used instead of 1,6-hexadiene.

Block copolymer represented by Formula 1c was carried out in the same manner as in Example 1, except that the mixing molar ratio of styrene, 1,4-divinylbenzene and n-butyl acrylate (BA) was 1:1:4. An electrolyte consisting of the coalescence {PEO-b-(S-co-DVB-co-BA)} was obtained.

[Formula 1c]

In Formula 1c, m and n represent the degree of polymerization, n is the weight average molecular weight of the ion conductive block (PEO block) was ^{controlled to be about 10 4} Daltons, and m is the weight average molecular weight of the block copolymer represented by Formula 1c. It was controlled to be about 56,000 Daltons.

a, b, and c all represent the mole fraction, the sum of which is 1, a is about 0.16665, b is about 0.16665, and c is about 0.6667. Thus, the ratio of a, b and c was 1:1:4.

Comparative Example 1: Preparation of electrolyte (structure) (S:DVB=4:1 molar ratio)

PEO-CTA represented by the following Formula 12 (weight average molecular weight: 10 ⁴ Daltons, polydispersity (Mw/Mn): about 1.11) was mixed with styrene and 1,4-divinylbenzene to obtain a polymer composition. The content of PEO-CTA in the composition was about 35% by weight, and the mixing ratio of styrene and 1,4-divinylbenzene was 4:1 molar ratio.

[Formula 12]

PEO-CTA

In Formula 12, n was controlled so that the weight average molecular weight of PEO-CTA represented by Formula 12 was 10 ^{4 Dalton.}

AIBN (Azobisisobutyronitrile), which is a radical initiator, is added to the polymer composition, and then heat-treated at about 100° C. for 3 hours to conduct a polymerization reaction. ). The content of AIBN was about 0.05 mol based on 1 mol of PEO-CTA.

Comparative Example 2: Preparation of electrolyte (S:DVB=4:1 molar ratio)

1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide: BMIPTFSI) of the following formula 13, which is an ionic liquid in a polymer composition, lithium The same as in Comparative Example 1, except that bis(trifluoromethylsulfonyl)imide (LiTFSA) and polyethylene glycol dimethyl ether (PEGDME) (number average molecular weight: about 250 Dalton) of the following formula 14 as salts were added. Conducted according to the method to prepare an electrolyte. The mixing ratio of the ionic liquid and the lithium salt was 3:1 molar ratio, and the mixing ratio of the ionic liquid and PEGDME was 80:20 by volume.

[Formula 13] [Formula 14]

Comparative Example 3: Preparation of electrolyte

N-methyl-N-propyl-pyrrolidium bis(trifluoromethanesulfonyl)imide) [PYR13+TFSI-] as an ionic liquid in the polymer composition, bis(trifluoromethylsulfonyl) as a lithium salt already An electrolyte was prepared in the same manner as in Comparative Example 1, except that LiTFSA and polyethylene glycol dimethyl ether (PEGDME) (number average molecular weight: about 250 Dalton) were added. The mixing ratio of the ionic liquid and the lithium salt was 3:1 molar ratio, and the mixing ratio of the ionic liquid and PEGDME was 80:20 by volume.

Comparative Example 4: Preparation of electrolyte (BA:DVB=4:1 molar ratio)

PEO-CTA (weight average molecular weight: 10 ⁴ Daltons, polydispersity (Mw/Mn): about 1.11) was mixed with n-butyl acrylate and 1,4-divinylbenzene to obtain a polymer composition. In the polymer composition, the content of PEO-CTA was about 35% by weight, and the mixing ratio of n-butyl acrylate and 1,4-divinylbenzene was 4:1 molar ratio.

[Formula 12]

PEO-CTA

In Formula 12, n was controlled so that the weight average molecular weight of PEO-CTA represented by Formula 12 was 10 ^{4 Dalton.}

AIBN (Azobisisobutyronitrile), which is a radical initiator, is added to the polymer composition and heat-treated at about 100° C. for 3 hours to carry out a polymerization reaction. ). The content of AIBN was about 0.05 mol based on 1 mol of PEO-CTA.

Production Example 1: Preparation of lithium battery (coin cell)

A mixture of LiCoO ₂ , carbon conductive agent (Denka Black) and polyvinylidene fluoride (PVdF) in a weight ratio of 92:4:4 was mixed with N-methylpyrrolidone (NMP) in an agate mortar to form a slurry. Was prepared. The slurry was bar-coated on an aluminum current collector having a thickness of 15 μm, dried at room temperature (25° C.), dried once again under vacuum and 120° C., and rolled and punched to prepare a 55 μm-thick positive electrode. .

The positive electrode was wetted in polyethylene glycol dimethyl ether (PEGDME) (weight average molecular weight: about 250 daltons) for 1 hour. A coin cell was manufactured by interposing the electrolyte prepared in Example 1 between the wetted positive electrode and the lithium metal thin film as the counter electrode.

Production Example 2-7: Manufacture of lithium battery (coin cell)

A coin cell was manufactured in the same manner as in Preparation Example 1, except that the electrolyte prepared according to Examples 2-7 was used instead of the electrolyte prepared according to Example 1.

Production Example 8: Preparation of lithium secondary battery (full cell)

First, an electrolyte composition was prepared by carrying out according to the following procedure.

PEO-CTA represented by the following Formula 12) (weight average molecular weight = 10 ⁴ , polydispersity: about 1.11) in a 4:4:1 molar ratio of styrene (styrene: hereinafter referred to as S), divinylbenzene (DVB), and The monomer mixture was obtained by mixing n-butyl acrylate. The content of PEO-CTA in the monomer mixture was about 35% by weight, and the mixing ratio of styrene, 1,4-divinylbenzene and n-butyl acrylate was 2:1:2 molar ratio.

[Formula 12]

PEO-CTA

In Formula 12, n was adjusted so that the weight average molecular weight of the polymer represented by Formula 12 was about 10 ^4.

In the monomer mixture, the ionic liquid N-methyl-N-propyl-pyrrolidium bis(trifluoromethanesulfonyl)imide) [PYR13+TFSI-], the lithium salt bis(trifluoromethylsulfonyl) Imide (LiTFSI) and polyethylene glycol dimethyl ether (PEGDME) (weight average molecular weight: about 250 Dalton) were added and mixed, and radical initiator AIBN (Azobisisobutyronitrile) was added, followed by stirring at room temperature (25° C.) to obtain an electrolyte composition. . In the composition, the content of PEO-CTA was 35% by volume, the total content of monomers was about 55% by volume, and the total content of the ionic liquid and lithium salt was 10% by volume.

The mixing ratio of the ionic liquid and the lithium salt was 3:1 molar ratio, and the mixing ratio of the ionic liquid and PEGDME was 80:20 by volume.

Lithium metal on which the electrolyte composition was coated with a doctor blade on the top of a lithium metal thin film (thickness: about 20 μm), and the electrolyte (cathode protective film) (thickness: about 17 μm) was formed in a vacuum oven at about 110° C. for about 12 hours A negative electrode was prepared.

Separately, LiCoO ₂ , a conductive agent (Super-P; Timcal Ltd.), polyvinylidene fluoride (PVdF), and N-pyrrolidone were mixed to obtain a positive electrode composition. In the positive electrode composition, _{the mixing weight ratio of LiCoO 2} , the conductive agent and PVDF was 97:1.5:1.5.
The positive electrode composition was coated on an aluminum foil (thickness: about 15 μm) and dried at 25° C., and the dried result was dried at about 110° C. in vacuum to prepare a positive electrode.

delete

A lithium secondary battery (anode/separator/electrolyte (cathode protective film)/cathode) was prepared by disposing a lithium metal negative electrode having an electrolyte (cathode protective film) formed on the positive electrode obtained according to the above process, and disposing a separator between the positive electrode and the electrolyte. PVDF-4 (Cheil Industries) was used as a separator.

A liquid electrolyte was added between the positive electrode and the electrolyte of the lithium secondary battery. As a liquid electrolyte, a lithium salt in which _{1.3M LiPF 6} was dissolved was added to a mixed solvent of ethylene carbonate (EC), propylene carbonate (PC), and fluoroethylene carbonate (FEC) in a volume ratio of 2:6:2.

Production Example 9: Manufacture of lithium secondary battery (full cell)

A lithium secondary battery was manufactured in the same manner as in Preparation Example 8, except that the liquid electrolyte used the liquid electrolyte obtained according to the following procedure.

The liquid electrolyte is polyethylene glycol dimethyl ether (PEGDME) in a volume ratio of 8:2:1,

It was obtained by adding a lithium salt in which 1M LiTFSI was dissolved in a mixed solvent of fluoroethylene carbonate (FEC) and trimethyl phosphate (TMP). Then, 2 parts by weight of lithium bis(oxalato) borate (LiBOB) was added to 100 parts by weight of bis(trifluoromethylsulfonyl)imide (LiTFSI).

Comparative Production Example 1: Preparation of coin cell

A mixture of LiCoO ₂ , carbon conductive agent (Denka Black) and polyvinylidene fluoride (PVdF) in a weight ratio of 92:4:4 was mixed with N-methylpyrrolidone (NMP) in an agate mortar to form a slurry. Was prepared. The slurry was bar-coated on an aluminum current collector having a thickness of 15 μm, dried at room temperature, dried again under vacuum and 120° C., and rolled and punched to prepare a positive electrode having a thickness of 55 μm.

The positive electrode was immersed in PEGDME (weight average molecular weight: 250 Dalcon) and wetting was performed for 1 hour. A coin cell was manufactured by interposing a mixture of an electrolyte prepared according to Comparative Example 1, an ionic liquid, and a lithium salt between the wetted positive electrode and a lithium metal thin film as a counter electrode.

As the ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide: BMIPTFSI) was used, and as the lithium salt, bis (Trifluoromethylsulfonyl)imide (LiTFSI) was used.

In the liquid electrolyte, the weight ratio of BMIPTFSI and LiTFSI was 3:1, and the mixing ratio of BMIPTFSI and PEGDME was 80:20 by volume.

Comparative Production Example 2: Preparation of coin cell

A mixture of LiCoO ₂ , carbon conductive agent (Denka Black) and polyvinylidene fluoride (PVdF) in a weight ratio of 92:4:4 was mixed with N-methylpyrrolidone (NMP) in an agate mortar to form a slurry. Was prepared. The slurry was bar-coated on an aluminum current collector having a thickness of 15 μm, dried at room temperature, dried again under vacuum and 120° C., and rolled to prepare a positive electrode having a thickness of 55 μm.

The positive electrode was immersed in PEGDME (weight average molecular weight: 250 Daltons) and wetting was performed for 1 hour. A coin cell was manufactured by interposing the electrolyte prepared according to Comparative Example 2 between the wetted positive electrode and the lithium metal thin film as the counter electrode.

Comparative Production Example 3: Preparation of Coin Cell

A coin cell was manufactured in the same manner as in Comparative Preparation Example 2, except that the electrolyte prepared according to Comparative Example 3 was used instead of the electrolyte prepared according to Comparative Example 2.

Comparative Production Example 4: Preparation of lithium secondary battery (full cell)

A lithium secondary battery was manufactured in the same manner as in Preparation Example 9, except that the thickness of the lithium negative electrode thin film was changed to about 40 μm without forming a negative electrode protective film on the lithium negative electrode thin film.

Evaluation Example 1: Conductivity measurement

1) Example 1-2 and Comparative Example 1

The conductivity of the electrolytes prepared according to Example 1, Example 2, and Comparative Example 1 was measured at 25°C according to the following method.

The electrolytes prepared according to Example 1-2 and Comparative Example 1 were subjected to a voltage bias of 10 mV in the frequency range of 1 Hz to 1 MHz, and the ionic conductivity was evaluated by scanning the temperature and measuring the resistance, and is shown in FIG. 2A. In FIG. a, “before wetting” indicates the state before wetting in polyethylene glycol dimethyl ether (PEGDME) (weight average molecular weight: about 250 dalton) in the electrolyte for about 1 hour, and “after wetting” indicates the state before wetting in polyethylene glycol dimethyl ether (PEGDME). It shows the state after wetting was performed for 1 hour.

Referring to FIG. 2A, it can be seen that the electrolytes prepared according to Examples 1 and 2 have improved conductivity compared to the electrolyte of Comparative Example 1.

2) Examples 2, 3 and 8 and Comparative Examples 1 and 4

The conductivity of the electrolytes prepared according to Examples 2, 3 and 8 and Comparative Examples 1 and 4 was measured at 25°C according to the following method.

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The electrolytes prepared according to Examples 2, 3 and 8 and Comparative Examples 1 and 4 were subjected to a voltage bias of 10 mV in the frequency range of 1 Hz to 1 MHz, and the conductivity was evaluated by scanning the temperature and measuring the resistance. I got it.

Referring to FIG. 2B, it can be seen that the electrolytes prepared according to Examples 2, 3 and 8 have improved conductivity compared to the electrolytes of Comparative Examples 1 and 4.

Evaluation Example 2: Electrochemical stability

A cell was fabricated by using the electrolyte according to Example 1, respectively, interposed between the lithium electrode and the stainless electrode. The cell was analyzed according to Linear Sweep Voltammetry (LSV) to examine the electrochemical stability, and the results of the linear scanning voltage analysis are shown in FIG. 3.

The measurement conditions for the linear scan voltage method were in the voltage range of 3V to 7V, the scan rate was about 0.5 mV/s, and the measurement temperature was about 25°C.

Referring to FIG. 3, it was found that the electrochemical stability of the cell employing the electrolyte of Example 1 was improved to about 4.5V.

Evaluation Example 3: Impedance Measurement

1) Production Example 1 and Comparative Production Example 1

Impedance was measured after charging and discharging by the AC impedance method at 25°C to the electrode of the coin cell of Production Example 1 and Comparative Production Example 1. For impedance measurement, an impedance analyzer (Solatron SI1260 impedance/gain-phase analyzer) was used, and a 4-probe method was used as a measurement method.

The impedance measurement results of the coin cells manufactured according to Preparation Example 1 and Comparative Preparation Example 1 are as shown in FIGS. 4A and 4B, respectively.

Referring to this, it can be seen that the cell of Fabrication Example 1 has significantly improved impedance characteristics compared to the case of Comparative Production Example 1.

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2) Production Example 2 and Comparative Production Example 2

The impedance of the coin cell manufactured according to Preparation Example 2 and Comparative Preparation Example 2 was described above.

Measurements were made in the same manner as the method applied to the coin cell manufactured according to Preparation Example and Comparative Preparation Example 1, and are shown in FIGS. 4C and 4D, respectively.

Referring to this, it was found that the impedance characteristic of the coin cell manufactured according to Preparation Example 2 (see FIG. 4C) was improved as compared with the case of Comparative Preparation Example 2 (FIG. 4D).

Evaluation Example 4: Filling Profile

In the coin cells prepared according to Preparation Example 1 and Comparative Preparation Example 3, charging was performed at 25°C at 0.05C until 4.3V was reached.

After this charging process, it was investigated whether or not cracks of the electrolyte occurred in the coin cells according to Comparative Production Example 3 and Production Example 1, and the results are shown in FIG. 5A.

As shown in Figure 5a, it was possible to observe the crack shape of the electrolyte in the coin cell of Comparative Production Example 3.

In addition, the charging profile of the coin cell according to Production Example 1 and Comparative Production Example 3 in which the above-described charging process was performed was examined. 5B shows a charging profile for a coin cell manufactured according to Comparative Preparation Example 3.

The coin cell manufactured according to Manufacturing Example 1 maintains a constant potential unlike the case of Comparative Manufacturing Example 3, whereas the coin cell manufactured according to Comparative Manufacturing Example 3 was charged by continuously decreasing the potential as shown in FIG. 5B. It was found that this was not done.

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Evaluation Example 5: Charge and Discharge Characteristics

1) Production Example 1, Comparative Production Example 1 and Comparative Production Example 2

Charging and discharging of the coin cells prepared according to Preparation Example 1 and Comparative Preparation Example 1-2 were performed according to the following procedure.

The coin cells prepared according to Production Example 1 and Comparative Production Example 1-2 were charged and discharged 50 times with a constant current of 0.1C in a voltage range of 3.0 to 4.3 V compared to lithium metal at room temperature (20-25° C.). This charging and discharging process was repeatedly performed 4 times.

After performing the charging/discharging process, the potential change according to the capacity is shown in FIGS. 6A to 6C.

In Figure 6a, 1a, 2a, 3a, 4a represent the 1st cycle, 2nd cycle, 3rd cycle, and 4th cycle charging graph, respectively, and 1b, 2b, 3b, 4b are 1st cycle, 2nd cycle, and 3rd cycle. The discharge graphs of the cycle and the fourth cycle are shown. And in FIGS. 6B to 6C, 1a, 3a, 5a, and 7a represent the 1st cycle, 3rd cycle, 5th cycle, and 7th cycle charging graph, respectively, and 1b, 3b, 5b, and 7b are 1st cycle and 3rd cycle, respectively. The discharge graphs of the cycle, the 5th cycle and the 7th cycle are shown.

The above Production Example except that the charging/discharging process was repeatedly performed 7 times compared to the method of evaluating the charging/discharging characteristics of the coin cell manufactured according to Manufacturing Example 1 for the coin cell manufactured according to Comparative Manufacturing Example 1-2. The charging/discharging characteristics of the coin cells manufactured according to Comparative Production Example 1-2 were evaluated in the same manner as the method for evaluating the charging/discharging characteristics of the coin cells manufactured according to 1.

The evaluation results of charging/discharging characteristics of the coin cell manufactured according to Preparation Example 1 and the coin cell manufactured according to Comparative Preparation Example 1-2 are shown in FIGS. 6A to 6C, respectively.

With reference to this, it was found that the charge/discharge characteristics of the coin cell manufactured according to Preparation Example 1 were improved compared to the coin cells manufactured according to Comparative Preparation Examples 1 and 2.

2) Production Example 2-7

The charging and discharging characteristics of the coin cell manufactured according to Preparation Example 2-7 were investigated.

The results for Preparation Example 2 are shown in FIG. 7.

Referring to this, it was confirmed that the coin cell manufactured according to Preparation Example 2 had excellent charge/discharge characteristics compared to the cases of Comparative Production Example 1 and Comparative Production Example 2 of FIGS. 6B and 6C. In addition, it was found that the coin cell manufactured according to Preparation Example 3-7 exhibited excellent charge/discharge characteristics as in Preparation Example 2.

3) Production Example 8

The lithium secondary battery prepared according to Preparation Example 8 was charged and discharged 55 times with a constant current of 0.1C in a voltage range of 3.0 to 4.3 V compared to lithium metal at room temperature (20-25°C). The results of the charging and discharging experiments in 1, 5, 10, 20, 40, and 50 cycles are shown in FIGS. 8 and 9. 8 is a graph showing a change in capacity and efficiency according to the number of cycles, and FIG. 9 is a graph showing a change in voltage according to the capacity.

The efficiency shown in FIG. 8 is calculated and shown according to Equation 1 below.

[Equation 1]

Efficiency (%) = (discharge capacity/charge capacity) × 100

Referring to FIG. 8, it was found that the lithium secondary battery manufactured according to Preparation Example 8 has excellent charge/discharge efficiency and capacity retention. And, referring to FIG. 9, it was confirmed that the lithium secondary battery manufactured according to Preparation Example 8 had excellent cycle characteristics.

4) Production Example 9 and Comparative Production Example 4

The lithium secondary batteries prepared according to Preparation Example 9 and Comparative Preparation Example 4 were charged and discharged 10 times at room temperature (20-25°C) with a constant current of 0.1C in a voltage range of 3.0 to 4.3 V compared to lithium metal. Subsequently, charging and discharging were performed 11 to 20 times with a constant current of 0.2C in a voltage range of 3.0 to 4.3 V. Thereafter, charging and discharging were performed 20 to 30 times with a constant current of 0.1 C in a voltage range of 3.0 to 4.3 V. The capacity characteristics according to the number of cycles are shown in FIG. 10. In FIG. 10, PIPS is for Production Example 4 and Bare Li is for Comparative Production Example 4.

Referring to FIG. 10, it was confirmed that the lithium secondary battery manufactured according to Preparation Example 9 had excellent cycle characteristics compared to the lithium secondary battery manufactured according to Comparative Preparation Example 4.

Evaluation Example 6: Young's modulus and tensile strength

For the electrolytes prepared according to Examples 1, 2, 3, and Comparative Example 1, Young's modulus and maximum tensile strength were measured through Lloyd LR-10K, and the electrolyte specimen was ASTM standard D638 ( Type V specimens).

The electrolyte was measured for tensile strength at a rate of 5 mm per minute ^{at 25 o C and a relative humidity of about 30%.}

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The above-described elastic modulus and tensile strength measurement results are shown in Table 1 below.

division Young's modulus (MPa) Tensile strength (MPa) Example 2 12.4 1.6 Example 3 1129 18.3 Comparative Example 1 0.081 6.1

Referring to Table 1, it was confirmed that the electrolyte prepared according to Example 3 had improved elastic modulus and tensile strength compared to the case of Comparative Example 1, thereby improving mechanical properties. In addition, the electrolyte prepared according to Example 2 had an increased modulus of elasticity compared to the case of Comparative Example 1. The tensile strength of the electrolyte prepared according to Example 2 was slightly smaller than that of Comparative Example 1, but it was confirmed that it had a tensile strength (about 0.1 mS/cm or more) suitable for use as an electrolyte. As described above, it was found that the electrolytes prepared according to Examples 2 and 3 exhibit excellent mechanical properties.

In addition, the electrolyte prepared according to Example 1 exhibited the same level of elastic modulus and tensile strength properties as the electrolytes of Examples 2 and 3.

Evaluation example 7: Electron scanning microscopy analysis

The electrolyte prepared according to Examples 1-8 was analyzed using a scanning electron microscope to investigate the size of the double-linked domain.

The size of the ion conductive domain of the electrolyte prepared according to Examples 1-8 was found to be about 1 μm or more.

In the above, one embodiment has been described with reference to the drawings and embodiments, but this is only illustrative, and those of ordinary skill in the art can understand that various modifications and other equivalent implementations are possible therefrom. will be. Therefore, the scope of protection of the present invention should be determined by the appended claims.

110: lithium battery 120: negative electrode
130: anode 140: separator

Claims (27)

An electrolyte comprising a block copolymer containing a co-continuous domain including an ion conductive phase and a structural phase,
The structure includes a polymer segment having a glass transition temperature of less than room temperature (25 ℃),
The ion conductive phase includes an ion conductive polymer,
The structure includes a polymer that is a polymerization product of i) a monofunctional polymerizable monomer, ii) a polyfunctional polymerizable monomer, and iii) a polymerizable monomer having a reactive functional group,
At the end of the polymer included in the structure, a residue derived from a chain transfer agent is bonded, and a linker derived from a chain transfer agent exists between the polymer for forming an ionic conduction phase and the polymer for forming the structure. And
The residue is -SC(=S)-R ₃ and the linker is -C(=O)-C(R ₁ )(R ₂ )- or -C(=O)-(CH ₂ ) _k -C(R ₁ )(R ₂ )- (k is an integer from 1 to 5),
R ₁ to R ₃ are independently of each other hydrogen, cyano group, C ₁ to C ₂₀ alkyl group, C ₂ to C ₂₀ alkenyl group, C ₆ to C ₅₀ aryl group, C ₆ to C ₅₀ heteroaryl group, C ₅ to C ₃₄ saturated or unsaturated carbocyclic group, C ₅ ~ C ₃₄ aromatic carbocyclic group, C ₅ ~ C ₃₄ heterocyclic group, C ₁ ~ C ₂₀ alkylthio group, C ₁ ~ C ₂₀ alkoxy group, or a C ₂ ~ C ₂₀ Is a dialkylamino group,
The polymerizable monomer having the reactive functional group is butyl acrylate, 1,6-hexadiene, 1,4-butadiene, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4- Hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol ( Meth)acrylate, acrylic acid, methacrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth)acryloyloxy butyric acid, itaconic acid, male Acid, 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, 4-isocyanatobutyl (meth)acrylate, (meth)acrylamide, N-vinyl Pyrrolidone, ethylene di (meth) acrylate, diethylene glycol (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylene propane tri (meth) acrylate, trimethylene propane triacrylate, 1, 3-butanediol (meth)acrylate, 1,6-hexanedioldi (meth)acrylate, allyl acrylate, N-vinyl caprolactam, and one or more selected from the group consisting of a compound represented by the following formula (10a),
The content of the polymerizable monomer having a reactive functional group is 0.2 to 0.7 mol based on 1 mol of the total of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the polymerizable monomer having a reactive functional group:
[Formula 10a]

. The method of claim 1,
In the polymerizable monomer having a reactive functional group, the reactive functional group is at least one selected from a functional group containing an ethylenically unsaturated bond, a hydroxy group, an amino group, an amide group, a carboxyl group, and an aldehyde group. The method of claim 1,
The electrolyte in which the polymerizable monomer having a reactive functional group is at least one selected from the group consisting of an acrylic monomer, a methacrylic monomer, and an olefin monomer having a reactive functional group. delete The method of claim 1,
The monofunctional polymerizable monomer is styrene, 4-bromostyrene, tertbutylstyrene, methyl methacrylate, isobutyl methacrylate, 4-methylpentene-1, butylene terephthalate, ethylene terephthalate, ethylene, propylene, Isobutyl methacrylate, butadiene, dimethylsiloxane, isobutylene, vinylidene fluoride, acrylonitrile, 1-butyl vinyl ether, vinyl cyclohexane, fluorocarbon, cyclohexyl methacrylate, amide, maleic anhydride ( maleic anhydride), maleic acid, methacrylic acid, and one or more electrolytes selected from the group consisting of vinylpyridine. The method of claim 1,
The polyfunctional polymerizable monomer is l,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene 1,2,4-trivinylbenzene, 4,4"-divinyl-5'-(4-vinylphenyl)-1,1':3',1"-terphenyl, 1,3-divinylnaphthalene, 1,8-divinylnaphthalene, l,3,5-trivinylnaphthalene, 2, 4-divinylbiphenyl, 3,5,7-trivinylnaphthalene, l,2-divinyl-3,4-dimethylbenzene, l,5,6-trivinyl-3,7-diethylnaphthalene, l, An electrolyte that is at least one selected from 3-divinyl-4,5-8-tributylnaphthalene and 2,2'-divinyl-4-ethyl-4'-propylbiphenyl. The method of claim 1,
The monofunctional polymerizable monomer is styrene and
The polyfunctional polymerizable monomer is divinylbenzene,
The electrolyte in which the polymerizable monomer having a reactive functional group is butyl acetate, 1,6-hexadiene, or 1,4-hexadiene. delete The method of claim 1,
The content of the monofunctional polymerizable monomer is 0.15 to 0.5 moles based on the total 1 mole of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the polymerizable monomer having a reactive functional group,
The content of the polyfunctional polymerizable monomer is 0.05 to 0.3 mol based on the total 1 mol of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the polymerizable monomer having a reactive functional group. The method of claim 1,
The mixture ratio of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the polymerizable monomer having a reactive functional group is 4:1:4, 2:1:2, 1:1:4, or 2:1:4 molar ratio. The method of claim 1,
The ion conducting phase is selected from among ether-based monomers, acrylic monomers, methacrylic monomers, amine-based monomers, imide-based monomers, alkyl carbonate-based monomers, nitrile-based monomers, phosphazine-based monomers, olefin-based monomers, diene-based monomers and siloxane-based monomers. An electrolyte comprising an ion conductive polymer containing at least one selected ion conductive repeating unit. The method of claim 1,
i) ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based,
At least one cation selected from piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, triazolium-based, and mixtures thereof,
^{_{ii) BF 4 -, PF 6}} -, AsF 6 -, SbF 6 -, AlCl 4 -, HSO 4 -, ClO 4 -, CH 3 SO 3 -, CF 3 CO 2 -, (CF 3 SO 2) 2 N ^{-, Cl -, Br -,} I -, SO 4 -, CF 3 SO 3 -, (C 2 F 5 SO 2) 2 N - , and _{(C 2 F 5 SO 2)} (CF 3 SO 2) N-, Electrolyte further comprising at least one ionic liquid selected from compounds containing at least one anion selected from at least one selected from. The method of claim 1,
LiSCN, LiN(CN) ₂ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiSbF _{6 ,} Li(CF ₃ SO ₂ ) ₃ C, LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ CF ₂ CF ₃ ) ₂ , LiPF ₃ (CF ₂ CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ (CF ₃ ) ₃ , LiB(C ₂ O ₄ ) ₂ , NaSCN, NaSO ₃ CF ₃ , KTFSI, NaTFSI, Ba(TFSI) ₂ , Pb(TFSI) ₂ , Ca(TFSI) ₂ and LiPF ₃ (CF ₂ CF ₃ ) ₃ An electrolyte further comprising one or more alkali metal salts or alkaline earth metal salts selected from among. The method of claim 1,
The electrolyte is a block copolymer of i) a polymer which is a polymerization product of styrene, 1,4-divinylbenzene and 1,6-hexadiene and ii) polyethylene oxide,
The electrolyte is a block copolymer of i) a polymer which is a polymerization product of styrene, 1,4-divinylbenzene and 1,4-hexadiene and ii) polyethylene oxide, or
i) A polymer that is a polymerization product of styrene, 1,4-divinylbenzene and butyl acrylate, and ii) an electrolyte that is a block copolymer of polyethylene oxide. The method of claim 1,
The electrolyte further comprises at _{least one inorganic particle selected from SiO 2} , TiO ₂ , ZnO, Al ₂ O ₃ , BaTiO ₃ , silsesquioxane having a cage structure, and a metal-organic framework (MOF). Containing electrolytes. The method of claim 1,
The electrolyte is an electrolyte comprising a polymerization reaction product of a composition comprising a chain transfer agent containing an ion conductive polymer, a monofunctional polymerizable monomer, a polyfunctional polymerizable monomer, and an elastically retaining polymerizable monomer having a reactive functional group. The method of claim 1,
The double-linked domain size is 1 μm or more,
The structure is an electrolyte comprising a polymerization reaction product of a composition comprising a monofunctional polymerizable monomer, a polyfunctional polymerizable monomer, and an elastically retaining polymerizable monomer having a reactive functional group. The method of claim 1,
The electrolyte further comprises at least one selected from a liquid electrolyte, a solid electrolyte, a gel electrolyte, a polymer ionic liquid, and a separator. A chain transfer agent containing an ion conductive polymer, which is a polymer for forming an ion conductive phase, and i) a monofunctional polymerizable monomer, which is a structural polymer forming monomer, ii) a polyfunctional polymerizable monomer, and iii) a polymerizable monomer having a reactive functional group. It is prepared by carrying out a polymerization reaction of the electrolyte composition,
The polymerizable monomer having the reactive functional group is butyl acrylate, 1,6-hexadiene, 1,4-butadiene, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4- Hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol ( Meth)acrylate, acrylic acid, methacrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth)acryloyloxy butyric acid, itaconic acid, male Acid, 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, 4-isocyanatobutyl (meth)acrylate, (meth)acrylamide, N-vinyl Pyrrolidone, ethylene di (meth) acrylate, diethylene glycol (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylene propane tri (meth) acrylate, trimethylene propane triacrylate, 1, 3-butanediol (meth)acrylate, 1,6-hexanedioldi (meth)acrylate, allyl acrylate, N-vinyl caprolactam, and one or more selected from the group consisting of a compound represented by the following formula (10a),
The content of the polymerizable monomer having a reactive functional group is 0.2 to 0.7 mol based on 1 mol of the total of the monofunctional polymerizable monomer, the polyfunctional polymerizable monomer, and the polymerizable monomer having a reactive functional group,
The chain transfer agent containing the ion conductive polymer is prepared by reacting a chain transfer agent with at least one selected from the group consisting of polyether, polyacrylic, polymethacrylic, and polysiloxane. A method for preparing an electrolyte to obtain the electrolyte of any one of claims 7 and 9 to 18:
[Formula 10a]

. The method of claim 19,
At least one selected from an ionic liquid, an alkali metal salt and an alkaline earth metal salt is further added to the electrolyte composition, or at least one selected from an ionic liquid, an alkali metal salt and an alkaline earth metal salt is further added to the electrolyte obtained by performing the polymerization reaction. Method for preparing an electrolyte. delete The method of claim 19,
The chain transfer agent is at least one selected from dithioesters, dithiocarbamates, trithiocarbonates, and xanthates. The method of claim 19,
The method for producing an electrolyte in which the polymerization reaction is carried out at 20 to 150°C. A secondary battery comprising a positive electrode, a negative electrode, and the electrolyte according to any one of claims 1 to 3, 5 to 7, and 9 to 18 interposed therebetween. The secondary battery according to claim 24, further comprising at least one selected from a liquid electrolyte, a solid electrolyte, a gel electrolyte, a polymer ionic liquid, an inorganic particle, and a separator. The method of claim 25,
The negative electrode is a lithium metal or lithium metal alloy electrode,
A secondary battery further comprising at least one selected from a liquid electrolyte, a gel electrolyte, a solid electrolyte, a separator, and a polymer ionic liquid between the electrolyte and the positive electrode. The method of claim 24,
A secondary battery comprising a sheet or film formed at least partially on one surface of the positive or negative electrode.

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