KR20170083387A - Electrolyte for lithium secondary battery and lithium secondary battery comprising the same - Google Patents

Abstract

i) a block comprising a conductive domain and an olefin domain;
And ii) a solvate ionic liquid containing a lithium salt and a glycidic material, wherein the conductive domain comprises a polymer comprising an alkylene oxide repeating unit, wherein the olefinic domain comprises There is provided an electrolyte for a lithium secondary battery comprising a polymer containing an acid modified olefin type repeating unit and a lithium secondary battery comprising the electrolyte.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrolyte for a lithium secondary battery and a lithium secondary battery including the same,

An electrolyte for a lithium secondary battery and a lithium secondary battery comprising the electrolyte are disclosed.

Lithium secondary batteries are high performance secondary batteries having the highest energy density among currently commercialized secondary batteries and can be used in various fields such as electric vehicles.

As the cathode of the lithium secondary battery, a lithium metal thin film may be used. When such a lithium metal thin film is used as a negative electrode, reactivity with a liquid electrolyte during charging and discharging is high due to high reactivity of lithium. Or a dendrite is formed on the lithium negative electrode thin film, so that the lifetime and stability of the lithium secondary battery employing the lithium metal thin film may be deteriorated, and improvement is required.

One aspect is to provide an electrolyte for a lithium secondary battery improved in mechanical properties.

Another aspect is to provide a lithium battery including the above-described electrolyte and having improved cell performance.

On one side

i) a block copolymer comprising a conductive domain and an olefin domain, and ii) a solvate ionic liquid containing a lithium salt and a glidant,

Wherein the conductive domain comprises a polymer comprising an alkylene oxide repeating unit,

The olefin-based domain is an electrolyte for a lithium secondary battery comprising a polymer containing an acid-modified olefin-based repeating unit.

According to another aspect, an anode; The cathode described above; And an electrolyte interposed therebetween are provided.

The negative electrode is a lithium metal negative electrode, and the electrolyte may be a lithium metal negative electrode protective layer.

The electrolyte for a lithium secondary battery according to an embodiment has a protective film having excellent mechanical properties and improved stability to a liquid electrolyte. By using such a negative electrode, a lithium battery having improved cycle life can be manufactured.

Figure 1 schematically illustrates the structure of a solvate ionic liquid according to one embodiment.
2A and 2B schematically illustrate the structure of a lithium secondary battery according to one embodiment.
3 schematically shows a structure of a lithium secondary battery according to another embodiment.
Figure 4 shows conductivity and tensile strength changes in the electrolyte prepared according to Examples 9, 10 and 15.
Figure 5 shows the change in conductivity and tensile strength in the electrolyte prepared according to Examples 5, 8 and 10.
6 shows the results of ionic conductivity and tensile strength evaluation according to Examples 9, 10, and 12.
FIG. 7 shows the electrochemical stability of a symmetric cell fabricated according to Production Example 1. FIG.
FIGS. 8A and 8B show voltage profiles for the symmetric cell fabricated according to Production Example 5. FIG.
FIG. 9 shows the results of cell lifetime evaluation for the symmetric cells fabricated according to Production Examples 6, 13, and 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an exemplary electrolyte for a lithium secondary battery and a lithium secondary battery including the same will be described in detail with reference to the accompanying drawings.

i) a block copolymer comprising a conductive domain and an olefin domain, and ii) a solvate ionic liquid containing a lithium salt and a glidant, wherein the conductive domain is an alkylene Wherein the olefinic domain comprises a polymer comprising an acid-modified olefin-based repeating unit. The present invention also provides an electrolyte for a lithium secondary battery, which comprises a polymer comprising an oxide repeating unit.

In the present specification, the conductive domain is a region in which the block copolymer contributes to exhibit excellent ionic conductivity. And the olefinic domain is a region that contributes to mechanical properties such as the tensile strength of an electrolyte containing a block copolymer as a nonconductive region.

The lithium metal electrode has a large electric capacity per unit weight, so that it is possible to realize a high capacity battery. However, in the case of a lithium metal electrode, a dendrite structure is formed and grown in the process of removing / attaching lithium ions, thereby causing a short circuit between the positive electrode and the negative electrode. In addition, the lithium metal electrode has high reactivity to the electrolyte and may cause a side reaction with the electrolyte, thereby deteriorating the cycle life of the battery. In order to compensate for this, a protective film and / or an electrolyte that can complement the surface of the lithium metal electrode are required.

The protective film and / or electrolyte according to the prior art has excellent ionic conductivity, but the mechanical properties are insufficient and the function of suppressing lithium dendrite growth is not satisfactory. A method of adding inorganic particles to the protective film and / or the electrolyte has been proposed, but in this case, the mechanical properties of the protective film and the electrolyte can be improved, but the interface resistance can be increased.

The electrolyte according to an embodiment solves the above-mentioned problems and has a property of not only improving mechanical properties but also having excellent ionic conductivity by containing a block copolymer containing a conductive domain and an olefinic domain and a sol-gel ionic liquid.

The solvate ionic liquid comprises a lithium salt and a glaze material. Here, the glare substance may be at least one selected from monoglyme, diglyme, triglyme and tetraglyme, and specifically, triglyme (triethylene glycol dimethyl ether) or tetraglyme (tetraethylene Glycol dimethyl ether). Oxygen is contained to coordinate the lithium salt. The glare material may contain, for example, four or five oxygen atoms to form coordination compounds having excellent stability when coordinated with lithium.

In the block copolymer containing an alkylene oxide repeating unit, the alkylene oxide repeating unit retains oxygen and can coordinate lithium. As such, when lithium is coordinated, the movement of lithium ions in the electrolyte may be partially disturbed.

However, the electrolyte according to one embodiment contains a solvate ionic liquid, and the solvate ionic liquid has a structure in which the lithium (11) of the lithium salt is coordinated to the oxygen of the glycidic material (10) By having the structure in which the anion X ^- (12) exists, the lithium ion mobility can be improved. Where X ^- is, for example, FSI ^- (fluorosulfonylimide) or TFSI ^- (trifluoromethane) sulfonimide.

In FIG. 1, tetraethylene glycol dimethyl ether is used as an example of the glare material. When such a solvate ionic liquid is contained, the coordination bond of the alkylene oxide repeat unit and the lithium ion is excessively formed in the block copolymer as compared with the case where the electrolyte does not contain the solvate ionic liquid, Can be effectively prevented. As a result, as shown in FIG. 1, the electrolyte is excellent in electrochemical stability due to the coordination bond between lithium and a glare material, and the lithium ion mobility is improved on the surface of the lithium negative electrode, thereby providing an electrolyte having excellent ionic conductivity. The solvate ionic liquid is one of the Lewis bases and has an excellent effect of stabilizing the surface of the lithium metal and has an excellent effect of inhibiting lithium dendrite formation on the surface of the lithium metal anode.

The mixing molar ratio of the lithium salt of the solvate ionic liquid to the glaze material is from 1: 1 to 1: 4, for example from 1: 1.3 to 1: 2. A solvate ionic liquid can be formed at such a mixed molar ratio.

The mixing ratio of the alkylene oxide repeating unit and the solvate ionic liquid of the block copolymer is from 5: 1 to 20: 1, for example, from 10: 1 to 15: 1.

The mixing ratio of the alkylene oxide repeating unit, the polymer and the polymer including the olefin repeating unit is 1: 9 to 9: 1, for example, 1: 1.5 to 1: 8, specifically 1: 1.5 to 1: 5 . When the above-mentioned mixing weight ratio is satisfied, the ion conductivity of the electrolyte is excellent and the mechanical properties are excellent, so that the growth of the dendrite on the surface of the lithium metal can be effectively suppressed.

The polymer block having an alkylene oxide repeating unit in an electrolyte according to an embodiment is a conductive region, and the polymer block containing an olefin repeating unit is a nonconductive region.

The lithium salt can be used as long as it is commonly used in a lithium secondary battery. Lithium salt, for example, _{LiSCN, LiN (CN) 2,} LiClO 4, LiBF 4, LiAsF 6, LiPF 6, LiCF 3 SO 3, LiN (SO 2 F) 2, (SO ₃ CF ₂ ) ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) ₂ , LiSbF ₆ And at least one selected from LiPF ₃ (CF ₂ CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ (CF ₃ ) ₃ and LiB (C ₂ O ₄ ) ₂ is used. The content of the lithium salt is 10 to 70 parts by weight, for example, 20 to 50 parts by weight, based on 100 parts by weight of the block copolymer. When the content of the lithium salt is in the above range, the ion conductivity of the electrolyte is excellent.

When LiN (SO ₂ F) ₂ is used as the lithium salt, the ionic conductivity and mechanical properties of the electrolyte containing the solvate ionic liquid are superior to those in the case of using LiN (CF ₃ SO ₂ ) ₂ .

The electrolyte according to one embodiment has a tensile strength of 1 MPa or more at 25 DEG C, for example, 1 to 9.8 MPa or more, specifically 50 to 80 MPa. And the ionic conductivity of the electrolyte is 1 X 10 ^-4 S / cm or more at 25 ° C, for example, 1 × 10 ^-4 S / cm to 4.0 × 10 ^-4 S / cm. The ionic conductivity of the electrolyte is 1 × 10 ^-3 S / cm or more at 60 ° C.

The thickness of the electrolyte according to one embodiment is 1 to 200 占 퐉, for example, 40 to 150 占 퐉.

According to one embodiment, the electrolyte further includes a liquid electrolyte, whereby the ion conductivity of the electrolyte can be further improved.

The liquid electrolyte further includes at least one selected from an organic solvent and an ionic liquid. Examples of the organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, fluoroethylene carbonate, gamma butyrolactone, succinonitrile, sulfoline, dimethyl sulfone, ethyl methyl sulfone, , Adiponitrile, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether.

In the electrolyte according to one embodiment, mechanical properties are improved while ensuring excellent ionic conductivity by using a block copolymer containing a conductive domain and an olefin domain. Further, since a uniform ion distribution is secured at the interface between the electrode and the electrolyte, dendrite formation can be effectively suppressed. By using such an electrolyte, a lithium secondary battery having improved lifetime characteristics can be produced.

The block copolymers constituting the electrolyte can be synthesized in large quantities using atom transfer radical polymerization (ATRP) and reversible addition fragmentation chain transfer polymerization (RAFT), and the production cost is low.

The block copolymer contains an olefin repeating unit and is excellent in crystallinity and excellent in thermal stability. Thermal stability can be confirmed by differential scanning calorimetry analysis. The glass transition temperature of the block copolymer is 150 to 300 占 폚.

The content of the polymer block containing the olefin repeating unit is 50 to 90 parts by weight, for example, 60 to 89 parts by weight, based on 100 parts by weight of the total amount of the block copolymer. When the content of the polymer block containing the olefin repeating unit is within the above range, an electrolyte having excellent mechanical properties can be obtained.

A polymer containing an olefin repeating unit is a polymer containing an acid-modified olefin repeating unit. The polymer containing an acid-modified olefin repeating unit is at least one selected from the group consisting of maleic acid-modified polyethylene, maleic acid-modified polybutylene, maleic acid-modified polyisobutylene, and maleic acid-modified polypropylene.

The degree of grafting in the polymer containing the acid-modified olefin repeating unit is from 1.0 to 20.0% by weight. And the average number of acidic groups per molecule is from 1 to 3, for example 1.7. For example, in maleic acid-modified olefins, the average number of maleic groups per molecule is from 1 to 3, for example, 1.7. An electrolyte containing a polymer containing an acid-modified olefin repeating unit having such a degree of graft has excellent mechanical properties.

The weight average molecular weight of the polymer block containing the alkylene oxide repeating unit in the block copolymer is 1,000 Daltons or more, for example, 2,000 to 500,000 Daltons, specifically 3,000 to 400,000 Daltons.

The weight average molecular weight of the polymer block containing the olefin repeating unit is 1,000 Daltons or more, for example, 2,000 to 500,000 Daltons, specifically 3,000 to 400,000 Daltons. When such a polymer block having a weight average molecular weight is used, an electrolyte having excellent mechanical properties can be obtained.

According to one embodiment, the block copolymer includes a block copolymer comprising a maleic acid-modified polypropylene first block and a polyethylene oxide second block; A block copolymer comprising a maleic acid-modified polypropylene first block and a polypropylene oxide second block; A block copolymer comprising a maleic acid-modified polybutylene first block and a polyethylene oxide second block; Or a block copolymer comprising a maleic acid-modified polybutylene first block and a polypropylene oxide second block. The mixing weight ratio of the first block to the second block is from 1.5: 1 to 8: 1, for example, from 1.5: 1 to 5: 1.

The electrolyte may further include inorganic particles. When such an inorganic particle is further included, an electrolyte improved in mechanical properties can be produced. The average particle size of the inorganic particles may be 1 탆 or less, for example, 500 nm or less, specifically 100 nm or less. For example, the particle size of the inorganic particles may be from 1 nm to 100 nm. For example, the particle size of the inorganic particles may be from 5 nm to 100 nm. For example, the particle size of the inorganic particles may be 10 nm to 100 nm. For example, the particle size of the inorganic particles may be 10 nm to 70 nm. For example, the particle size of the inorganic particles may be 30 nm to 70 nm. When the particle size of the inorganic particles is within the above range, an electrolyte excellent in film forming property and excellent in mechanical properties can be produced without lowering the ion conductivity.

As the inorganic particles, SiO ₂ , TiO ₂ , ZnO, Al ₂ O ₃ , BaTiO ₃ , silsesquioxane having a keez structure, and metal-organic framework (MOF) particles are Li _{1 + x + y} Al _x Ti _{2 - x} Si _y P _{3 - y} O ₁₂ (0 <x <2, 0 ≦ y <3), Pb (Zr, Ti) O ₃ (PZT), Pb _{1 - x} La _x Zr _{1 -y} Ti _{y O 3 (PLZT) (O≤x <} 1, O≤y <1), PB (Mg 3 Nb 2/3) O 3 -PbTiO 3 (PMN-PT), HfO 2, SrTiO 3, SnO 2, CeO 2 _{, Na 2 O, MgO, NiO} , CaO, BaO, ZnO, ZrO 2, y 2 O 3, SiC, lithium phosphate (Li ₃ PO _4), lithium titanium phosphate _{(Li x Ti y (PO 4} ) 3, 0 < x <2, 0 <y < 3), lithium aluminum titanium phosphate _{(Li x Al y Ti z (} PO 4) 3, 0 <x <2, 0 <y <1, 0 <z <3), Li 1 + _{x + y} (Al, Ga) _x (Ti, Ge) _{2 - x} Si _y P _{3 - y} O ₁₂ (O _{? x} ? 1, O _{? y} ? 1), lithium lanthanide titanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (LixGeyPzSw, 0 <x < _{x N y, 0 <x <} 4, 0 <y <2), SiS 2 (Li x Si y S z, 0 <x <3,0 <y <2, 0 <z <4) based glass, P ₂ S ₅ (Li _x P _y S _z , 0 <x <3, 0 <y < 3, 0 < z < 7) series glass, Li ₂ O, LiF, LiOH, Li ₂ CO ₃ , LiAlO ₂ , Li ₂ O- Al ₂ O ₃ -SiO ₂ -P ₂ O ₅ -TiO ₂ -GeO ₂ system Ceramics, and garnet-based ceramics Li _{3 + x} La ₃ M ₂ O ₁₂ (M = Te, Nb, or Zr).

The silsesquioxane of the cage structure may be, for example, Polyhedral Oligomeric Silsesquioxane (POSS). There are no more than eight silicones present in such POSS, for example six or eight.

The silsesquioxane of the cage structure may be a compound represented by the following formula

All.

[Chemical Formula 1]

^{_{Si k O 1 .5k (R 1}} ) a (R 2) b (R 3) c

In the above formula R ¹ , R ² , and R ³ are independently of each other hydrogen,

A substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C2-C30 alkynyl group, A substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted C2-C30 heteroaryl group, a substituted or unsubstituted C4-C30 carbon ring Group, or a silicon-containing functional group.

In the above formula (1), k = a + b + c and 6? K? 20.

The silsesquioxane of the cage structure may be a compound represented by the following formula (2) or a compound represented by the following formula (3).

 (2)

Wherein R _{1 to} R ₈ are independently selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C2-C30 Substituted or unsubstituted C2-C30 alkynyl group, substituted or unsubstituted C6-C30 aryl group, substituted or unsubstituted C6-C30 aryloxy group, substituted or unsubstituted A C2-C30 heteroaryl group, a substituted or unsubstituted C4-C30 carbon ring group, or a silicon-containing functional group.

 (3)

In Formula 3, R ₁ -R ₆ are independently hydrogen, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C2-C30 to each other Substituted or unsubstituted C2-C30 alkynyl group, substituted or unsubstituted C6-C30 aryl group, substituted or unsubstituted C6-C30 aryloxy group, substituted or unsubstituted A C2-C30 heteroaryl group, a substituted or unsubstituted C4-C30 carbon ring group, or a silicon-containing functional group.

According to one embodiment, the silsesquioxane of the cage structure is R _{1 -} R ₇ is a heptathobutyl group. The silsesquioxane of the cage structure may be, for example, heptaisobutyl-t8-silsesquioxane.

The content of the inorganic particles is 1 to 40 parts by weight, for example, 5 to 20 parts by weight, based on 100 parts by weight of the block copolymer. When the content of the inorganic particles is within the above range, an electrolyte having excellent mechanical properties and ionic conductivity can be produced.

The metal-organic skeleton structure is a porous crystalline compound in which a metal ion of group 2 to 15 or a metal ion cluster of group 2 to 15 is formed by a chemical bond with an organic ligand.

The organic ligand means an organic group capable of chemical bonding such as coordination bond, ionic bond or covalent bond. For example, the organic ligand is an organic group having two or more sites capable of binding to the metal ion described above, A structure can be formed.

The Group 2 to Group 15 metal ions may be at least one selected from the group consisting of Co, Ni, Mo, W, Ru, Os, Cd, beryllium, (Ba), Sr, Fe, Mn, Cr, V, Al, Ti, Zr, Zr, (Pt), copper (Cu), zinc (Zn), magnesium (Mg), hafnium (Hf), Nb, tantalum (Ta), Re, rhodium (Rh), iridium (Ir), palladium , Ag, Sc, Y, In, Thl, Si, Ge, Sn, Pb, As, Sb) and bismuth (Bi), and the organic ligand is at least one selected from aromatic dicarboxylic acid, aromatic tricarboxylic acid, imidazole compound, tetrazole compound, 1,2,3- A sulfonic acid, an aromatic phosphoric acid, an aromatic sulfinic acid, an aromatic phosphinic acid, a bipyridine, an amino group, an imino group, an acyl group, A compound having at least one functional group selected from the group consisting of a methine group, a methane group, a methane group, a methane dithio acid (-CS ₂ H) group, a methane dithioate anion (-CS ₂ ^- ) group, a pyridine group and a pyrazine group.

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

The above-mentioned organic ligands may specifically be a group derived from a compound represented by the following general formula (4).

[Chemical Formula 4]

The metal-organic skeleton structure can be, for example, Ti ₈ O ₈ (OH) ₄ [O ₂ CC ₆ H ₄ -CO ₂ ] _6, Cu (bpy) (H ₂ O) ₂ (BF ₄ ) ₂ = 4, 4'-bipyridine}, Zn 4 O (O 2 CC 6 H 4 -CO 2) 3 (Zn-terephthalic acid-MOF, Zn-MOF) or _{Al (OH) {O 2 CC} 6 H 4 -CO ₂ }.

The electrolyte according to one embodiment may further include at least one selected from an ionic liquid, a polymeric ionic liquid, and an oligomer, which are conventionally used in a lithium secondary battery.

The ionic liquid refers to a salt in a liquid state or a room-temperature molten salt at room temperature, which has a melting point below room temperature and is composed of only ions. The ionic liquid may be selected from the group consisting of i) an ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, And at least one cation selected from the group consisting of 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 ^- , (FSO 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 ^- .

The ionic liquid may be, for example, N-methyl-N-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide N-butyl-N-methylpyrrolidiumbis (3-trifluoromethylsulfonyl) (Trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide and 1-ethyl-3-methylimidazolium bis Or more.

The content of the ionic liquid is 5 to 40 parts by weight, for example, 10 to 20 parts by weight, based on 100 parts by weight of the block copolymer. When the content of the ionic liquid is within the above range, an electrolyte excellent in ionic conductivity and mechanical properties can be obtained.

The polymeric ionic liquid may be obtained by polymerizing an ionic liquid monomer, or may be a polymeric compound. Such a polymeric ionic liquid has a high solubility in an organic solvent and has an advantage that ionic conductivity can be further improved when it is added to an electrolyte. In the case of obtaining a polymeric ionic liquid by polymerizing the ionic liquid monomer described above, The resultant is washed and dried, and then an anion suitable for imparting solubility to an organic solvent through anion substitution reaction is prepared.

The polymeric ionic liquid according to one embodiment includes at least one selected from the group consisting of i) ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolinium, oxazolium, pyridazinium, And at least one cation selected from the group consisting of 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 -, (FSO 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 -, NO 3 -, Al 2 Cl 7 -, (CF 3 SO 2) 3 C -, (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 &gt;} PO-. &Lt; ^/ RTI &gt;

According to another embodiment, the polymeric ionic liquid can be prepared by polymerizing an ionic liquid monomer. The ionic liquid monomer preferably has a functional group capable of polymerizing with a vinyl group, an allyl group, an acrylate group, a methacrylate group and the like, and is selected from the group consisting of ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, May have at least one cation selected from a pyrazolium series, an oxazolium series, a pyridazinium series, a phosphonium series, a sulfonium series, a triazole series and mixtures thereof and the above-mentioned anion.

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

[Chemical Formula 5]

[Chemical Formula 6]

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

(7)

In Formula 7, R ₁ and R ₃ independently represent hydrogen, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C2-C30 A substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C2-C30 heteroaryl group, and a substituted or unsubstituted C4-C30 carbon ring group. In Formula 10, R ₂ represents a chemical bond or represents a C1-C3 alkylene group, a C6-C30 arylene group, a C2-C30 heteroarylene group, or a C4-C30 carbon ring group,

X ^- represents an anion of the ionic liquid, and n is 500 to 2,800.

[Chemical Formula 8]

In the formula 8 ^Y-X is of the general formula (7) ^- is defined in the same manner as, n is from 500 to 2800.

Y ^- in formula (8) is, for example, bis (trifluoromethanesulfonyl) imide (TFSI), bis (fluoromethanesulfonyl) imide, BF ₄ or CF ₃ SO ₃ .

Polymeric ionic liquids include, for example, poly (1-vinyl-3-alkylimidazolium), poly (1-allyl-3-alkylimidazolium), poly (1- (methacryloyloxy- and selected from imidazolium) ^{_{cation, CH 3 COO -, CF 3}} COO -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (FSO 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 - from Selected anions.

The compound represented by the above formula (8) includes polydiallyldimethylammonium bis (trifluoromethanesulfonyl) imide.

The electrolyte according to one embodiment can be used as a protective film for a lithium secondary battery such as a lithium air battery, a lithium ion battery, and a lithium polymer battery. For example, the electrolyte can be used as a protective film of a lithium metal battery having a lithium metal cathode, for example, a protective film for a high-voltage lithium metal battery. The above-described electrolyte can be prepared as a free standing type membrane. Here, "high voltage" refers to a case where the charging voltage is in the range of 4.0V to 5.5V.

Hereinafter, a method of manufacturing an electrolyte for a lithium secondary battery according to one embodiment will be described.

First, a block copolymer containing a conductive domain and an olefin-based domain, a glycidic material, a lithium salt and an organic solvent are mixed at 25 to 100 ° C, for example, at about 90 ° C to obtain a composition for forming an electrolyte.

The composition for forming an electrolyte is coated on a substrate and dried to prepare an electrolyte. The process of preparing the electrolyte is carried out in an anhydrous condition in a glove box or dryer. The anhydrous conditions are carried out in a dry box under an inert gas atmosphere such as argon gas. The reason for this is that the operation is performed under anhydrous conditions because the glare material is sensitive to moisture and may adversely affect the characteristics of the finally obtained electrolyte.

The drying is carried out under a vacuum condition at 30 to 90 캜, for example, 80 캜.

The organic solvent may be any organic solvent that can be used in the art. For example, there can be mentioned, for example, xylene, tetrahydrofuran, N-methylpyrrolidone, acetonitrile, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran,? -Butyrolactone, dioxolane, But are not limited to, tetrahydrofuran, dioxolane, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, , Dimethyl ether, or a mixture thereof, and the like can be used. The content of the organic solvent is 100 to 5000 parts by weight based on 100 parts by weight of the block copolymer.

The composition for forming an electrolyte may further contain inorganic particles. The electrolyte-forming composition may further include at least one selected from an ionic liquid and a polymeric ionic liquid.

When the electrolyte is formed using the composition for forming an electrolyte, at least a portion of the lithium metal may be coated and dried to prepare an electrolyte.

The above-mentioned coating method can be used as long as it is a commonly available method for forming a protective film. For example, methods such as spin coating, roll coating, curtain coating, extrusion, casting, screen printing, inkjet printing, doctor blading and the like can be used.

The electrolyte has a voltage range of 0 V to 6.0 V, for example, 0 V

0.0 &gt; 0V &lt; / RTI &gt; to 4.0V. The protective film according to one embodiment can be applied to an electrochemical device operated at a high voltage by having an electrochemically stable wide voltage window.

According to another aspect, there is provided a lithium battery including an anode, a cathode according to an embodiment, and an electrolyte interposed therebetween. The lithium battery may be, for example, a lithium secondary battery.

The electrolyte may be a mixed electrolyte type including at least one selected from a liquid electrolyte, a solid electrolyte, a gel electrolyte, a polymer ionic liquid, and a separator.

The lithium battery may further include at least one selected from a liquid electrolyte, a polymer ionic liquid, a solid electrolyte, and a gel electrolyte. At least one selected from a liquid electrolyte, a polymeric ionic liquid, a gel electrolyte, and a solid electrolyte may be interposed between the anode and the polymer electrolyte. As described above, the ionic conductivity and the mechanical properties of the electrolyte can be further improved by including at least one selected from a liquid electrolyte, a polymeric ionic liquid, a solid electrolyte, and a gel electrolyte.

According to one embodiment, the electrolyte further comprises a liquid electrolyte such that the structural domain of the electrolyte forms an ionically conductive pathway through the electrolyte. The liquid electrolyte further includes at least one selected from an organic solvent, an ionic liquid, and a lithium salt.

Examples of the organic solvent include a carbonate compound, a glycol compound, and a dioxolane compound.

The carbonate compound may be ethylene carbonate, propylene carbonate, dimethyl carbonate, fluoroethylene carbonate, diethyl carbonate, or ethyl methyl carbonate. The glycine compound may be selected from the group consisting of poly (ethylene glycol) dimethyl ether (PEGDME, polyglyme), tetra (ethylene glycol) dimethyl ether (TEGDME, tetraglyme) Poly (ethylene glycol) monoacrylate (PEGDL), poly (ethylene glycol) monoacrylate, poly (ethylene glycol) PEGMA), and poly (ethylene glycol) diacrylate (PEGDA).

Examples of dioxolane-based compounds include 3-dioxolane, 4,5-diethyl-dioxolane, 4,5-dimethyl-dioxolane, 4-methyl- -1,3-dioxolane. &Lt; / RTI &gt; The organic solvent may be selected from the group consisting of 2,2-dimethoxy-2-phenylacetophenone, dimethyl ether (DME), 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, gamma butyrolactone, 1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (1,1,2,2-Tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether).

The gel electrolyte is an electrolyte having a gel form, and any of those known in the art can be used. The gel electrolyte may contain, for example, a polymer and a polymeric ionic liquid. The polymer may be, for example, a solid graft (block) copolymer electrolyte.

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

Examples of the organic solid electrolyte include a polymer including a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, and an ionic dissociation group Can be used.

The inorganic solid _{electrolyte, Li 3 N, LiI, Li} 5 NI 2, Li 3 N-LiI-LiOH, Li 2 SiS 3, Li 4 SiO 4, Li 4 SiO 4 -LiI-LiOH, Li 3 PO 4 - _{Li 2 S-SiS 2, Cu} 3 N, LiPON, Li 2 S.GeS 2 .Ga 2 S 3, Li 2 O.11Al 2 O 3, (Na, Li) 1 + x Ti 2x 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 , Na-Silicates, Li _0.3 La _0.5 TiO ₃ , Na ₅ MSi ₄ O ₁₂ (M is a rare earth element such as _{Nd, Gd, Dy) 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 _1y Ti _y ) _2x (PO ₄ ) ₃ (X0.8, 0Y1.0, M is Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, _{1 + x + y Q x Ti} 2x Si y P 3y O 12 (0 < x0.4, 0 < y0.6, 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).

The lithium metal electrode may be a lithium metal thin film electrode or a lithium metal alloy electrode, and a liquid electrolyte containing at least one selected from an organic solvent, an ionic liquid, and a lithium salt may be further interposed between the electrolyte and the anode.

When a negative electrode according to one embodiment is employed, the lithium secondary battery can be manufactured with improved capacity retention. Such a lithium battery is widely used in fields such as cell phones, notebook computers, batteries for power generation facilities such as wind power and solar power, electric vehicles, uninterruptible power supplies, and household batteries due to high voltage, capacity and energy density.

2A and 2B schematically show a structure of a lithium battery including a protective film according to one embodiment.

As shown in FIG. 2A, the lithium battery has a structure in which an electrolyte 23 according to an embodiment is interposed between the anode 21 and the cathode 22. The electrolyte (24) may also serve as a protective film at the same time. Here, the cathode 22 is a lithium metal electrode. A protective film 24 may be further included between the electrolyte 24 and the cathode 22. The electrolyte 23 may further include at least one selected from a liquid electrolyte, a polymer ionic liquid, a solid electrolyte, and a gel electrolyte. The electrolyte may further include a separator.

As the electrolyte 23 described above is disposed on at least a part of the cathode 22, the cathode surface can be electrochemically stabilized while being mechanically stabilized. Therefore, the formation of dendrites on the surface of the negative electrode during charging and discharging of the lithium battery can be suppressed, and the interface stability between the negative electrode and the electrolyte is improved. Therefore, the cycle characteristics of the lithium battery can be improved.

As the separator, polyethylene, polypropylene, polyvinylidene fluoride or a multilayer film of two or more thereof may be used. The separator may be a polyethylene / polypropylene double layer separator, a polyethylene / polypropylene / polyethylene three layer separator, a polypropylene / Polyethylene / polypropylene three-layer separator and the like can be used. The separator may further include an electrolyte containing a lithium salt and an organic solvent.

2A and 2B, the anode may be a porous anode. The porous anode includes pores which contain pores or which do not exclude the formation of an anode intentionally so that the liquid electrolyte can be permeated into the inside of the anode by capillary phenomenon or the like. For example, the porous anode includes a cathode obtained by coating and drying a cathode active material composition comprising a cathode active material, a conductive agent, a binder and a solvent. The thus obtained positive electrode may contain pores existing between the positive electrode active material particles. Such a porous anode may be impregnated with a liquid electrolyte.

According to another embodiment, the anode may comprise a liquid electrolyte, a gel electrolyte, a solid electrolyte, and the like. The liquid electrolyte, the gel electrolyte, and the solid electrolyte may be used as an electrolyte of a lithium battery in the related art, as long as they do not deteriorate the cathode active material by reacting with the cathode active material during charging and discharging.

In FIGS. 2A and 2B, a lithium metal thin film can be used as a cathode. The thickness of the lithium metal thin film may be 100 탆 or less. For example, the lithium battery can obtain a stable cycle characteristic even for a lithium metal thin film having a thickness of 100 m or less. For example, in the lithium battery, the thickness of the lithium metal thin film may be 80 탆 or less, for example, 60 탆 or less, specifically 0.1 to 60 탆. In a conventional lithium battery, when the thickness of the lithium metal thin film is reduced to 100 탆 or less, the thickness of lithium deteriorated due to side reaction, dendrite formation, or the like is increased and it is difficult to realize a lithium battery that provides stable cycle characteristics. However, by using the electrolyte according to one embodiment, a lithium battery having stable cycle characteristics can be manufactured.

3 schematically shows a structure of a lithium secondary battery according to another embodiment.

Referring to this, an anode 33, a cathode 32 according to one embodiment, and an electrolyte 34 are included. The positive electrode 33, the negative electrode 32, and the electrolyte 34 described above are wound or folded to be accommodated in the battery case 35. Then, an electrolyte is injected into the battery case 35 and sealed with a cap assembly 36, thereby completing the lithium secondary battery 31. The battery case may have a cylindrical shape, a rectangular shape, a thin film shape, or the like. For example, the lithium battery may be a large-sized thin-film battery.

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

The constituent elements constituting the lithium battery including the electrolyte according to one embodiment and the method of manufacturing the lithium battery having such constituent elements will be described in more detail as follows.

The positive electrode active material for producing the positive electrode 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. And any cathode active material available in the art may be used.

For example, Li _a A _{1 - b} B _b D ₂ , where 0.90? A? 1.8, and 0? B? 0.5; Li _a E _1-b B _b O _{2 -c} D _c wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0 _{? C?} 0.05; LiE _{2 - b} B _b O _{4 - c} D _{c where} 0? B? 0.5, 0 _{? C?} 0.05; Li _a Ni _{1 -b- c} Co _b B _c D _? Wherein, in the formula, 0.90 _{? A?} 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0? Li _a Ni _{1 -b- c} Co _b B _c O _{2 - ?} F _? Wherein, in the formula, 0.90? A? 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0 <? Li _a Ni _{1 -b- c} Co _b B _c O _{2 - ?} F _? Wherein, in the formula, 0.90? A? 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0 <? Li _a Ni _{1 -b- c} Mn _b B _c D _? Wherein, in the formula, 0.90 _{? A?} 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0? Li _a Ni _{1 -b- c} Mn _b B _c O _{2 - ?} F _? Wherein, in the formula, 0.90? A? 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0? Li _a Ni _{1 -b- c} Mn _b B _c O _{2 - ?} F _? Wherein, in the formula, 0.90? A? 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0? Li _a Ni _b E _c G _d O ₂ wherein 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 wherein 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, 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, 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} ); _{(0≤f≤2) Li (3-f} ) Fe 2 (PO 4) 3; A compound represented by any one of the formulas of LiFePO ₄ can 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, a rare earth element or a combination 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 combinations 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 the following formula (9), a compound represented by the following formula (10) or a compound represented by the following formula (11).

[Chemical Formula 9]

Li _a Ni _b Co _c Mn _d O ₂

In the above formula (9), 0.90? A? 1.8, 0? B? 0.9, 0? C? 0.5, and 0? D?

[Chemical formula 10]

Li ₂ MnO ₃

(11)

LiMO ₂

In the above formula (11), M is Mn, Fe, Co, or Ni.

The anode is prepared according to the following method.

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

A conductive agent may further be added to the cathode active material composition.

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

As the conductive agent, binder and solvent in the positive electrode active material composition, the same materials as those for the negative electrode active material composition may be used. It is also possible to add a plasticizer to the cathode active material composition and / or the anode active material composition to form pores inside the electrode plate.

The content of the cathode active material, the conductive agent, the binder, and the solvent is a level commonly used in a lithium battery. At least one of the conductive agent, the binder and the solvent may be omitted depending on the use and configuration of the lithium battery.

The cathode may be a lithium metal thin film or a lithium alloy thin film.

The lithium alloy may include lithium and a metal / metalloid capable of alloying with lithium. For example, the metal / metalloid capable of being alloyed with lithium may be at least one selected from the group consisting of Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloy (Y is an alkali metal, an alkali earth metal, (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 is a transition metal, a rare earth element or a combination element thereof and not Si) , Not Sn), and the like. The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Se, Te, Po, or a combination thereof.

As the electrolyte, a separator and / or a lithium salt-containing nonaqueous electrolyte commonly used in a lithium battery may be used.

The separator is made of an insulating thin film having high ion permeability and mechanical strength. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 20 mu m. As such a separator, for example, an olefin-based polymer such as polypropylene; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid polymer electrolyte is used as the electrolyte, the solid polymer electrolyte may also serve as a separator.

As the specific examples of the separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more thereof may be used. Examples of the separator include a polyethylene / polypropylene double layer separator, a polyethylene / polypropylene / polyethylene triple layer separator, Polypropylene / polyethylene / polypropylene three-layer separator, and the like.

The lithium salt-containing nonaqueous electrolyte is composed of a nonaqueous 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 nonaqueous electrolytic solution includes an organic oil. These organic solvents may be used as long as they can be used as organic solvents in the art. Examples of the solvent include 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 N, N-dimethylformamide, N, N-dimethylformamide, tetrahydrofuran, tetrahydrofuran, N-dimethylacetamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether or mixtures thereof. And an example wherein the lithium salt is, for _{example, LiPF 6, LiBF 4, LiSbF} 6, LiAsF 6, LiClO 4, LiCF 3 SO 3, Li (CF 3 SO 2) 2 N, Li (FSO 2) 2 N, LiC 4 _{F 9 SO 3, LiAlO 2,} LiAlCl 4, LiN (C x F 2x + 1 SO2) (C y F 2y + 1 SO 2) ( with the proviso that x and y are natural numbers), there is LiCl, LiI and mixtures thereof. For the purpose of improving the charge-discharge characteristics and the flame retardancy, non-aqueous electrolytes include, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, hexamethylphosphoamide hexamethyl phosphoramide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxyethanol, Etc. may be added. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability.

The lithium battery according to one embodiment is excellent in capacity and lifetime characteristics and can be used not only in a battery cell used as a power source of a small device but also in a middle- or large-sized battery pack or battery including a plurality of battery cells used as a power source of a middle- The module can also be used as a unit cell.

Examples of the medium and large-sized devices include an electric vehicle (EV) including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV) E-bike, an electric motorcycle electric power tool electric power storage device including an electric scooter (E-scooter), but the present invention is not limited thereto.

As used herein, "alkyl" refers to fully saturated branched or unbranched (or linear or linear) hydrocarbons.

Non-limiting examples of "alkyl" include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n- pentyl, isopentyl, neopentyl, isoamyl, -Methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl and the like.

"Alkyl" at least one hydrogen atom of an alkyl group of a halogen atom, halogen-substituted C1-C20 (for _{example: CCF 3, CHCF 2, CH} 2 F, CCl 3 , etc.), an alkoxy of C1-C20 alkoxy, C2-C20 of A sulfamoyl group, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, a C1-C20 alkyl group, a hydroxyl group, a nitro group, a cyano group, an amino group, an amidino group, a hydrazine, a hydrazone, C20 alkenyl, C2-C20 alkynyl, C1-C20 heteroalkyl, C6-C20 aryl, C6-C20 arylalkyl, C6-C20 heteroaryl, C7-C20 heteroaryl An alkyl group, a C6-C20 heteroaryloxy group, a C6-C20 heteroaryloxyalkyl group or a C6-C20 heteroarylalkyl group.

The term &quot; halogen atom &quot; includes fluorine, bromine, chlorine, iodine and the like.

"Alkenyl" refers to branched or unbranched hydrocarbons having at least one carbon-carbon double bond. Non-limiting examples of the alkenyl group include vinyl, allyl, butenyl, isopropenyl, isobutenyl and the like, and at least one hydrogen atom of the alkenyl may be substituted with the same substituent as the alkyl group described above .

"Alkynyl" refers to branched or unbranched hydrocarbons having at least one carbon-carbon triple bond. Non-limiting examples of the "alkynyl" include ethynyl, butynyl, isobutynyl, isopropynyl, and the like.

At least one hydrogen atom of &quot; alkynyl &quot; may be substituted with the same substituent as in the alkyl group described above.

"Aryl" also includes a group in which the aromatic ring is fused to one or more carbon ring rings. Non-limiting examples of &quot; aryl &quot; include phenyl, naphthyl, tetrahydronaphthyl, and the like. Also, at least one hydrogen atom in the &quot; aryl &quot; group may be substituted with the same substituent as in the case of the above-mentioned alkyl group.

"Heteroaryl" means monocyclic or bicyclic organic compounds containing one or more heteroatoms selected from N, O, P or S and the remaining ring atoms carbon. The heteroaryl group may contain, for example, from 1 to 5 hetero atoms, and may include 5-10 ring members. The S or N may be oxidized to have various oxidation states.

Examples of heteroaryl include thienyl, furyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, , 5-oxadiazolyl, 1,3,4-oxadiazolyl group, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, Thiadiazolyl, isothiazol-3-yl, isothiazol-4-yl, isothiazol-5-yl, oxazol- Yl, isoxazol-3-yl, 1,2,4-triazol-5-yl, Yl, pyrid-3-yl, 2-pyrazin-4-yl, 1,2,3-triazol-5-yl, tetrazolyl, 2-yl, pyrazin-4-yl, pyrazin-5-yl, 2-pyrimidin-2-yl, 4-pyrimidin-2-yl or 5-pyrimidin-2-yl.

The term &quot; heteroaryl &quot; includes those where the heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocycle.

The &quot; carbon ring &quot; group used in the formula refers to a saturated or partially unsaturated non-aromatic monocyclic, bicyclic or tricyclic hydrocarbon group. Examples of monocyclic hydrocarbons include cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, and the like. Examples of bicyclic hydrocarbons are bornyl, decahydronaphthyl, bicyclo [2.1.1] hexyl, bicyclo [2.2.1] heptyl, bicyclo [2.2.1] heptenyl, or bicyclo [2.2.2] octyl. And examples of tricyclic hydrocarbons include adamantly.

 "Heterocycle" is a cyclic hydrocarbon containing at least one heteroatom and may contain from 5 to 20, for example from 5 to 1, carbon atoms. Wherein the heteroatom is one selected from sulfur, nitrogen, oxygen and boron.

"Alkoxy "," aryloxy ", and "heteroaryloxy" mean alkyl, aryl, and heteroaryl, respectively, bonded to an oxygen atom herein.

Will be explained in more detail through the following examples and comparative examples. However, the embodiments are for illustrative purposes only and are not intended to be limiting.

Example  1: Preparation of electrolyte

(Weight average molecular weight (Mw: 22,000), LiFSI and tetraethylene (hereinafter referred to as " OEO ") The molar ratio of OEO, LiFSI and G4 in the composition was 10: 3.0: 4.0, and the molar ratio of OEO to the sum of G4 of LiFSI was 10: 7.0. , And the content of xylene was about 2000 parts by weight based on 100 parts by weight of OEO.

As the nonconductive polyolefin block in the block copolymer, maleic acid-modified polypropylene (Mw = 3,000, average number of maleic acid groups per molecule: 1.7) , And the mixing ratio of the nonconductive polyolefin block to the conductive polyethylene oxide block (Mw = 3,400) in the block copolymer was 62:38 by weight.

The mixture was stirred and subjected to a homogenization process at about 90 ° C for 4 hours. The resultant was then placed in a Teflon dish of an in-house-built stainless steel drying box and then sealed in a sealed box at about 80 ^° C. under vacuum (0.2 MPa / cm ² ) for about 24 hours Lt; RTI ID = 0.0 &gt; 150 &lt; / RTI &gt;

Example  2-12, 15: Preparation of electrolyte

An electrolyte was prepared in the same manner as in Example 1 except that the molar ratio of OEO, LiFSI, and G4 was changed as shown in Table 1 below.

division The molar ratio of OEO, LiFSI and G4 The molar ratio of the sum of OEO, LiFSI and G4 Example 2 10: 1.4: 2.6 10: 4.0 Example 3 10: 1.75: 3.0 10: 4.75 Example 4 10: 1.5: 2.6 10: 4.1 Example 5 10: 1.45: 2.5 10: 3.95 Example 6 10: 2.0: 2.0 10: 4.0 Example 7 10: 1.75: 2.5 10: 4.25 Example 8 10: 1.35: 2.5 10: 3.85 Example 9 10: 1.5: 3.0 10: 4.5 Example 10 10: 1.3: 2.6 10: 3.9 Example 11 10: 0.8: 1.6 10: 2.4 Example 12 10: 1.5: 2.0 10: 3.5 Example 15 10: 1.4: 2.8 10: 4.2

Example  13

Except that LiTFSI was used instead of LiFSI in the preparation of the composition for electrolyte formation, and the molar ratio of OEO, LiTFSI and G4 was 10: 2.0: 2.0 and the molar ratio of OEO and LiTFSI was 10: 4.0, To prepare an electrolyte.

Example 14

Except that LiTFSI was used instead of LiFSI in the preparation of the composition for electrolyte formation, and the molar ratio of OEO, LiTFSI and G4 was 10: 1.5: 3.0, and the molar ratio of OEO and LiTFSI was 10: 4.5. To prepare an electrolyte.

Comparative Example 1: Preparation of electrolyte

5 g of the nonconductive polyolefin block and the conductive polyethylene oxide block copolymer (OEO) (Sanyo Chemical Ltd) used in Example 1 were added to 100 ml of xylene and this was added to a solution of 1- And stirred for 2 hours. The xylene content was about 2000 parts by weight based on 100 parts by weight of OEO

Next, LiFSI was added to the mixture, and the mixture was stirred at 90 캜 for 4 hours in an argon gas atmosphere to prepare a composition for forming an electrolyte. In this composition, the mixing molar ratio of OEO and LiFSI was 10: 1.4. The composition was dried in a Teflon dish under vacuum conditions at 80 DEG C for 20 hours to prepare an electrolyte having a thickness of about 150 mu m.

[Production of symmetric cell]

Production Example 1

A lithium metal was laminated on both sides of the electrolyte prepared according to Example 1 to prepare a symmetric cell.

Production Example  2-15

A symmetric cell was fabricated in the same manner as in Production Example 1, except that the electrolyte prepared in Example 2-15 was used in place of the electrolyte prepared in Example 1.

Comparative Production Example 1

A symmetric cell was fabricated in the same manner as in Production Example 1, except that the electrolyte prepared in Comparative Example 1 was used in place of the electrolyte prepared in Example 1.

Evaluation example  4: ion conductivity

The ionic conductivities of the electrolytes prepared in Example 1-10 and Comparative Example 1 were measured

Was measured according to the following method. The electrolyte was subjected to a voltage bias of 10 mV in the frequency range of 1 Hz to 1 MHz, the temperature was scanned, and the ion conductivity was evaluated by measuring the resistance. The evaluation results are shown in Table 2 below.

division Conductivity (× 10 ^-4 Scm ^-1 ) 25 ℃ 60 ° C Example 1 4.0 20.6 Example 2 2.10 7.65 Example 3 1.95 6.80 Example 4 1.77 6.40 Example 5 1.34 4.97 Example 6 0.966 6.60 Example 7 0.933 6.60 Example 8 0.933 4.48 Example 9 - 3.14 Example 10 - 3.60 Comparative Example 1 0.00045 -

Referring to Table 2, it was found that the electrolyte prepared according to Example 1-10 had improved conductivity as compared with Comparative Example 1. It was also found that the electrolyte prepared according to Examples 9 and 10 exhibited excellent conductivity.

Evaluation example  5: Tensile modulus  And Elongation

The tensile strength of the electrolyte prepared according to Example 1-12 and Comparative Example 1 was measured using DMA800 (TA Instruments), and the electrolyte specimen was prepared through ASTM standard D412 (Type V specimens) .

The tensile strength evaluation results are shown in Table 3 below.

division Tensile Strength (MPa) Example 1 1.0 Example 2 3.7 Example 3 1.4 Example 4 2.2 Example 5 5.1 Example 6 2.5 Example 7 6.1 Example 8 7.3 Example 9 5.5 Example 10 9.8 Example 11 9.2 Example 12 6.7 Comparative Example 1 13

As shown in Table 3, it was found that the electrolyte prepared according to Example 1-12 had excellent tensile strength. As shown in Table 3, the electrolyte of Comparative Example 1 has an excellent tensile strength, but as can be seen from Table 2, the ionic conductivity is poor and it is difficult to actually apply the electrolyte as an electrolyte.

Evaluation example  6: Ionic conductivity - Evaluation of tensile strength

1) Examples 9, 10, 15

The changes in the conductivity and tensile strength according to ranges in the electrolyte (10OEO-x (LiFSI-2G4) prepared according to Examples 9, 10 and 15 are shown in Fig.

2) Examples 5, 8 and 10

The changes in the conductivity and tensile strength according to the range of x in the electrolyte (10OEO-xLiFSI-2.5G4) prepared according to Examples 5, 8 and 10 are shown in Fig.

Referring to FIG. 4, the electrolytes prepared according to Examples 5, 8, and 10 have excellent ion conductivity and excellent tensile strength characteristics.

3) Embodiment  9, 10 and 12

The results of ionic conductivity and tensile strength evaluation according to Examples 9, 10 and 12 are shown in FIG.

Referring to FIG. 5, it can be seen that the electrolytes prepared according to Examples 9 and 10 are excellent in ionic conductivity and tensile strength.

Evaluation example  3: Electrochemical stability

The cyclic voltammetry was performed on the symmetric cell manufactured in Production Example 1,

, The electrochemical stability of the composite electrolyte layer coated on the lithium metal for a voltage range of 0 to 6 V (vs. Li) at a scan rate of 1 mV / sec was evaluated. The electrochemical stability evaluation results are shown in Fig.

Referring to FIG. 7, it was found that the lithium secondary battery produced according to Preparation Example 1 was electrochemically stable in the range of 0 to 5 V.

Evaluation example  4: Paragraph time

The voltage profile was examined for the symmetric cell fabricated according to Production Example 5. Was performed at ⁽² at 60 ° C 0.25 mA cm) when the evaluation conditions A (at 60 ° C 0.5 mA cm ^-2) or conditions B.

The results of short-circuit time evaluation are shown in Figs. 8A and 8B.

Referring to Fig. 8A, the voltage of the symmetric cell at a current density of 0.5 mA cm &lt; ^{2 &} gt ^; was observed to have a sudden voltage drop of about 1.5 hours. As shown in Fig. 8B, a sharp voltage drop was observed at a current density of 0.25 mA cm & lt ^; &quot; ^{2 &} gt ^; at 45 hours. This cell voltage drop is due to a short circuit due to the lithium dendrite. Referring to the results shown in FIGS. 8A and 8B, it can be seen that the symmetric cell of Production Example 5 is excellent in safety.

Evaluation example  5: Charging and discharging  Characteristics (cell life)

The symmetric cells fabricated according to Preparation Examples 6, 13 and 14 were subjected to constant current charging at a current of 0.1 C rate at 25 DEG C and then cut-off at a current of 0.05 C rate in the constant voltage mode. Then, the discharge was performed at a constant current of 0.1 C rate during the discharge (Mars phase, 1 ^st cycle). The charging and discharging process was performed two more times to complete the conversion process.

The symmetric cell having undergone the above-described conversion step was charged at a constant current of 0.5 C at 60 DEG C and then subjected to a constant current discharge at a current of 1.0 mA at 0.2 C.

The above charge / discharge process was repeated 30 times. The voltage change with time was evaluated and shown in Fig.

Referring to FIG. 9, it can be seen that the symmetric cells manufactured according to Production Examples 6, 13 and 14 have excellent cell lifetimes. Among them, the cell life of the symmetric cell of Production Example 6 using LiFSI was superior to that of Production Examples 13 and 14.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the exemplary embodiments or constructions. It will be apparent to those skilled in the art that various modifications and variations are possible in light of the above teachings will be. Accordingly, the scope of protection of the present invention should be determined by the appended claims.

10: Glare substance 11: Lithium salt lithium
12: Negative ion
23: electrolyte 24: protective film
30: Lithium battery 22, 32: cathode
21, 33: anode 34: separator
35: Battery case 36: Cap assembly

Claims (20)

i) a block comprising a conductive domain and an olefin domain;
Copolymer and ii) a solvate ionic liquid containing a lithium salt and a gaseous material,
Wherein the conductive domain comprises a polymer comprising an alkylene oxide repeating unit,
Wherein the olefinic domain comprises a polymer comprising an acid modified polyolefin repeat unit. The method according to claim 1,
Wherein the molar ratio of the lithium salt to the glaze material in the salt ionic liquid is 1:15 to 1: 4. The method according to claim 1,
Wherein the glaze material is at least one selected from the group consisting of monoglyme, diglyme, triglyme, and tetraglyme. The method according to claim 1,
The polymer containing an acid-modified olefin-based repeating unit is a maleic acid-modified polyolefin. The method according to claim 1,
The block copolymer; And the solvate ionic liquid is in a molar ratio of 5: 1 to 20: 1. The method according to claim 1,
Wherein the electrolyte further comprises inorganic particles. The method according to claim 1,
Wherein the weight ratio of the polymer comprising an acid-modified olefin-based repeating unit to the polymer containing an alkylene oxide repeating unit is 1: 9 to 9: 1. The method according to claim 1,
The polymer comprising an acid-modified olefin-based repeating unit is at least one selected from the group consisting of acid-modified polyethylene, acid-modified polybutylene, acid-modified polyisobutylene, and acid-modified polypropylene. The method according to claim 1,
Wherein the block copolymer has a number average molecular weight of 10,000 to 200,000 daltons. The method according to claim 1,
The lithium salt _{LiSCN, LiN (CN) 2,} LiClO 4, LiBF 4, LiAsF 6, LiPF 6, LiCF 3 SO 3, Li (FSO 2) 2 N, Li (CF 3 SO 2) 3 C, LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) ₂ , LiSbF ₆ And at least one selected from LiPF ₃ (CF ₂ CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ (CF ₃ ) ₃ and LiB (C ₂ O ₄ ) ₂ . The method according to claim 6,
The metal-organic framework (MOF) particles of SiO ₂ , TiO ₂ , ZnO, Al ₂ O ₃ , BaTiO ₃ , and the silsesquioxane structure of the structure are Li _{1 + x + y} Al _{x Ti 2 -x Si y P 3-} y O 12 (0 <x <2, 0≤y <3), Pb (Zr, Ti) O 3 (PZT), Pb 1 - x La x Zr 1 -y Ti y _{O 3 (PLZT) (O≤x <} 1, O≤y <1), PB (Mg 3 Nb 2/3) O 3 -PbTiO 3 (PMN-PT), HfO 2, SrTiO 3, SnO 2, CeO 2 _{, Na 2 O, MgO, NiO} , CaO, BaO, ZnO, ZrO 2, Y 2 O 3, SiC, lithium phosphate (Li ₃ PO _4), lithium titanium phosphate _{(Li x Ti y (PO 4} ) 3, 0 < x <2, 0 <y < 3), lithium aluminum titanium phosphate _{(Li x Al y Ti z (} PO 4) 3, 0 <x <2, 0 <y <1, 0 <z <3), Li 1 + _{x + y} (Al, Ga) _x (Ti, Ge) _{2 - x} Si _y P _{3 - y} O ₁₂ (O _{? x} ? 1, O _{? y} ? 1), lithium lanthanide titanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (LixGeyPzSw, 0 <x < _{x N y, 0 <x <} 4, 0 <y <2), SiS 2 (Li x Si y S z, 0 <x <3,0 <y <2, 0 <z <4) based glass, P ₂ S ₅ (Li _x P _y S _z , 0 < x < 3, 0 <y <3, 0 <z <7) based _{glass, Li 2 O, LiF, LiOH} , Li 2 CO 3, LiAlO 2, Li 2 O-Al 2 O 3 -SiO 2 -P 2 O 5 -TiO 2 - Wherein the electrolyte is at least one selected from the group consisting of GeO ₂ ceramics and Garnet ceramics Li _{3 + x} La ₃ M ₂ O ₁₂ (M = Te, Nb, Zr). The electrolyte for a lithium secondary battery according to claim 1, wherein the polymer containing the ethylene oxide repeating unit is at least one selected from the group consisting of polyethylene oxide, polybutylene oxide and polypropylene oxide. The method according to claim 1,
Wherein the degree of grafting in the polymer containing the acid-modified olefin repeating unit is 1.0 to 20.0 wt%. The method according to claim 1,
Wherein the content of the lithium salt is 10 to 70 parts by weight based on 100 parts by weight of the block copolymer. The method according to claim 1,
Wherein the electrolyte has a thickness of 1 to 200 占 퐉. The method according to claim 1,
Wherein the tensile strength is 1 MPa or more at 25 占 폚. The method according to claim 1,
The brush bait ionic liquid is tetra-glyme, and LiN (SO ₂ F) include ₂ (LiFSI) or tetra-glyme, and LiN (SO ₂ CF ₃₎ a lithium secondary battery electrolyte containing ₂ (LiTFSI). The method according to claim 1,
Wherein the block copolymer comprises a maleic acid-modified polypropylene first block and a polyethylene oxide second block;
A block copolymer comprising a maleic acid-modified polypropylene first block and a polypropylene oxide second block;
A block copolymer comprising a maleic acid-modified polybutylene first block and a polyethylene oxide second block; or
A block copolymer comprising a maleic acid-modified polybutylene first block and a polypropylene oxide second block; and an electrolyte for the lithium secondary battery. 18. A lithium secondary battery comprising a positive electrode, a negative electrode according to any one of claims 1 to 18, and an electrolyte interposed therebetween. 20. The method of claim 19,
Wherein the negative electrode is a lithium metal negative electrode, and the electrolyte is a lithium metal negative electrode protective layer.

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