KR101746927B1 - Lithium electrode and lithium battery compring the same - Google Patents

Abstract

The present invention relates to a lithium electrode and a lithium battery including the lithium electrode.

Description

TECHNICAL FIELD [0001] The present invention relates to a lithium electrode and a lithium battery including the lithium electrode.

This application claims the benefit of the filing date of Korean Patent Application No. 10-2014-0072249 filed with the Korean Intellectual Property Office on June 13, 2014, the entire contents of which are incorporated herein by reference.

The present invention relates to a lithium electrode and a lithium battery including the lithium electrode.

The chemical cell consists of an anode (anode), a cathode (cathode), a separator separating the cathode / anode, and an electrolyte for eliminating the polarization generated during the electrochemical reaction, And a battery using lithium as a negative electrode is generally referred to as a lithium battery.

Since lithium is a highly reactive metal, the lithium electrode including lithium has a problem of stability that is difficult to handle the electrode itself during the process.

When lithium metal is used as the electrode, lithium dendrites are formed in the charging and discharging process, and the dendrites may short-circuit the battery.

Accordingly, there is a demand for research and development of a lithium electrode for simultaneously improving the stability of the lithium electrode and the performance and stability of the lithium cell including the lithium electrode.

ECS, 2002, 5, (12) A286 ~ 289, Live Scanning Electron Microscope Observations of Dendritic Growth in Lithium / Polymer Cells

The present application is intended to provide a lithium electrode and a lithium battery including the same.

In order to solve the above problems, the present application is directed to an electrode layer including lithium; And

And a protective layer comprising at least one functional group selected from -SO ₃ Li, -COOLi, and -OLi on at least one surface of the electrode layer.

The present application also provides a lithium battery including the lithium electrode.

The lithium electrode according to one embodiment of the present application has an effect of improving the stability.

The lithium electrode according to one embodiment of the present application has an effect of improving the lithium ion conductivity.

The lithium battery according to one embodiment of the present application has an effect of improving durability.

The lithium battery according to one embodiment of the present application has an effect of inhibiting the growth of lithium dendrite and preventing a short circuit.

The lithium battery according to one embodiment of the present application has an effect of improving the life and stability of the battery.

1 is a graph showing the performance of a cell manufactured according to the comparative example and the example of the present application.
2 is a schematic view of a lithium electrode according to one embodiment of the present application including a conventional lithium electrode and a protective layer.

The present application will be described in detail below.

The present application relates to an electrode layer comprising lithium; And

And a protective layer comprising a lithium ion conductive polymer lithium ion conductive polymer provided on at least one surface of the electrode layer and containing at least one functional group selected from -SO ₃ Li, -COOLi, and -OLi. do.

The lithium electrode according to one embodiment of the present application has an effect that the stability of the electrode itself is improved due to the protective layer. Therefore, it is easy to handle the electrode in the process, and even when it is included in the battery, the growth of lithium dendrites is suppressed and short-circuiting is prevented. Further, the life and stability of the battery can be improved.

2 is a schematic view of a lithium electrode according to one embodiment of the present application including a conventional lithium electrode and a protective layer.

As shown in FIG. 2, in general, lithium dendrite is generated during charging and discharging of a battery. When a protective layer is applied, the growth of lithium dendrite can be physically blocked to improve the charging / discharging efficiency. In Figure 2, X is a schematic representation of lithium dendrites failing to physically grow due to the protective layer.

According to one embodiment of the present application, the lithium ion conductive polymer may include a repeating unit represented by the following formula (D).

 [Chemical Formula D]

In the above formula (D)

R is a substituted or unsubstituted hydrocarbon group selected from the group consisting of fluorine, oxygen, nitrogen and sulfur,

X is -SO ₃ Li, -COOLi or -OLi,

and y is 2 to 100,000.

In the present specification, the term "hydrocarbon group" means a group having a carbon skeleton in which carbon (C) is replaced with at least one selected from the group consisting of oxygen (O), nitrogen (N) And hydrogen (H) can be replaced by halogen, especially fluorine (F).

According to one embodiment of the present application, the terminal group of the lithium ion conductive polymer containing the repeating unit represented by the formula (D) may be selected from among hydrogen, a halogen group, a hydroxyl group and an amine group.

The repeating unit represented by the formula (D) may have a weight average molecular weight of 500 to 1,000,000, specifically 100,000 to 1,000,000.

According to one embodiment of the present application, the formula (D) may be represented by the following formula (E).

(E)

In the above formula (E)

A is -OCF ₂ CF (CF ₃₎ -, or a bond directly,

k is an integer of 1 to 30,

s is an integer from 1 to 10,

and y is an integer of 2 to 100,000.

According to one embodiment of the present application, the formula E may be represented by the following formulas E-1, E-2, E-3 or E-4.

[E-1]

[Formula E-2]

[Formula E-3]

[Formula E-4]

In Formulas (E-1) to (E-4), k and y are the same as defined in Formula (E).

According to one embodiment of the present application, the lithium ion conductive polymer may include a copolymer including a repeating unit represented by the following formula (A) and a repeating unit represented by the following formula (B).

(A)

[Chemical Formula B]

In the above Formulas A and B,

m and n represent the number of repeating units,

1? M? 500, 1? N? 500,

X ₁ , X ₂ and X ₃ are the same or different and each independently represents one of the following formulas (1) to (3)

[Chemical Formula 1]

(2)

(3)

In the above Chemical Formulas 1 to 3,

L ₁ is either a direct connection, -CZ ₂ Z ₃ -, and any of the substituted or unsubstituted monovalent fluorene unsubstituted fluorene group 2 -, -CO-, -O-, -S-, -SO 2 -, -SiZ 2 Z 3 One,

Z ₂ and Z ₃ are the same or different and are each independently any one of hydrogen, an alkyl group, a trifluoromethyl group (-CF ₃ ) and a phenyl group,

S ₁ to S ₅ are the same or different from each other, and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted amine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

a, b, c, p and q are the same or different and independently an integer of 0 or more and 4 or less,

p + q? 6,

a 'is an integer of 1 to 5,

In the formula (B), Y ₁ is represented by any one of the following formulas (4) to (6)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

In the above formulas 4 to 6,

L ₂ is a direct bond or any one selected from -CO-, -SO ₂ -, and a substituted or unsubstituted divalent fluorene group,

d, e, f, g and h are the same as or different from each other, and each independently an integer of 0 to 4,

f + g? 6,

b 'is an integer of 1 or more and 5 or less,

T ₁ to T ₅ are the same or different, each independently of at least one - and SO ₃ Li, or -COOLi -OLi, the rest are the same or different, and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted amine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group.

"는 인접한 치환기와 결합할 수 있는 위치를 나타낸다.In the present specification,

Quot; represents a position capable of bonding with an adjacent substituent.

Illustrative examples of such substituents are set forth below, but are not limited thereto.

In the present specification, examples of the halogen group include fluorine, chlorine, bromine or iodine.

In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 60, particularly 1 to 40, more particularly 1 to 20. Specific examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, hexyl and heptyl.

In the present specification, the alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 60, more preferably 2 to 40, and more particularly 2 to 20.

In the present specification, the alkoxy group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 60, more preferably 1 to 40, and more particularly 1 to 20.

In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms, more preferably 3 to 40 carbon atoms, and more preferably 5 to 20 carbon atoms, and particularly preferably a cyclopentyl group and a cyclohexyl group.

In the present specification, the heterocycloalkyl group includes at least one of S, O and N, and is not particularly limited, but preferably has 2 to 60 carbon atoms, specifically 2 to 40, more specifically 3 to 20, A pentyl group, and a cyclohexyl group are preferable.

In the present specification, the number of carbon atoms of the amine group is not particularly limited, but is preferably 1 to 60, more preferably 1 to 40, and more particularly 1 to 20. Specific examples of the amine group include a methylamine group, a dimethylamine group, an ethylamine group, a diethylamine group, a phenylamine group, a naphthylamine group, a biphenylamine group, an anthracenylamine group, a 9- , A diphenylamine group, a phenylnaphthylamine group, a ditolylamine group, a phenyltolylamine group, a triphenylamine group, and the like, but are not limited thereto.

In the present specification, the aryl group may be monocyclic or polycyclic, and the number of carbon atoms is not particularly limited, but is preferably 6 to 60, particularly 6 to 40, more particularly 6 to 20. Specific examples of the aryl group include monocyclic aromatic and naphthyl groups such as phenyl group, biphenyl group, triphenyl group, terphenyl group and stilbene group, binaphthyl group, anthracenyl group, phenanthrenyl group, pyrenyl group, perylenyl group, But are not limited to, a cyclic aromatic group such as a cyclopentyl group, a cyclohexenyl group, a cyclohexenyl group, a cyclohexenyl group, a chlorenyl group, a fluorenyl group, an acenaphthacenyl group, a triphenylene group and a fluoranthene group.

In the present specification, the heteroaryl group includes at least one of S, O and N as a hetero atom, and the number of carbon atoms is not particularly limited, but is preferably 2 to 60, particularly 2 to 40, more particularly 3 to 20 . Specific examples of the heteroaryl group include pyridyl, pyrrolyl, pyrimidyl, pyridazinyl, furanyl, thienyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl, Thiazolyl, thiazolyl, pyrazinyl, thiopyranyl, diazinyl, oxazinyl, thiazinyl, dioxinyl, triazinyl, tetrazinyl, quinolyl, iso Quinazolinyl, quinazolinyl, isoquinazolinyl, acridinyl, phenanthridinyl, imidazopyridinyl, diazanaphthalenyl, triazainene, indolyl, benzothiazolyl, benzoxazolyl, benzimidazole There may be mentioned, but not limited to, a condensed ring of a benzyl group, a benzyl group, a benzyl group, a benzyl group, a benzyl group, a benzyl group, a benzyl group, a benzyl group,

,

,

,

등이 있다. In the present specification, the fluorenyl group may be substituted by another substituent, and substituents may be bonded to each other to form a ring. For example,

,

,

,

.

As used herein, the term "substituted or unsubstituted" A halogen group; A nitrile group; A nitro group; A hydroxy group; Cyano; C ₁ to C ₆₀ linear or branched alkyl; C ₂ to C ₆₀ straight or branched chain alkenyl; C ₂ to C ₆₀ linear or branched alkynyl; C ₃ to C ₆₀ monocyclic or polycyclic cycloalkyl; A C ₂ to C ₆₀ monocyclic or polycyclic heterocycloalkyl; C ₆ to C ₆₀ monocyclic or polycyclic aryl; Substituted or unsubstituted with at least one substituent selected from the group consisting of C ₂ to C ₆₀ monocyclic or polycyclic heteroaryl, substituted or unsubstituted with at least two substituents selected from the group consisting of the substituents exemplified above it means. As described above, when two or more substituents are connected to each other, the two or more substituents may be the same or different.

According to one embodiment of the present application, m and n may be 2? M? 500 and 2? N? 500.

According to one embodiment of the present application, the copolymer may be a block copolymer.

In one embodiment of the present application, the ratio of m and n may be from 1: 9 to 7: 3. That is, when m + n is 1, n may have a ratio of 0.3 to 0.9.

In one embodiment of the present application, the ratio of m and n may be from 2: 8 to 6: 4. That is, when m + n is 1, n may have a ratio of 0.4 to 0.8.

According to one embodiment of the present application, the formula (1) may be represented by the following formula (1-1).

[Formula 1-1]

In Formula 1-1, S ₁ , S ₂ , a, b and L ₁ are the same as defined in Formula 1.

According to one embodiment of the present application, Formula 4 may be represented by Formula 4-1 below.

[Formula 4-1]

In Formula 4-1, T ₁ , T ₂ , d, e and L ₂ are as defined in Formula 4.

According to one embodiment of the present application, in the above Formulas A and B, X ₁ , X ₂ and X ₃ may be the same or different from each other, and each independently may be any one selected from the following formulas.

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

및

.

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

And

.

Wherein R and R 'are the same or different and are each independently -NO ₂ or -CF ₃ .

According to one embodiment of the present application, at least one of X ₁ , X ₂ and X ₃ in the above formulas (A) and (B) may be represented by the following formula (11).

(11)

In Formula 11,

S ₆ to S ₈ are the same or different from each other, and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted amine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

s and t are the same as or different from each other, and each independently represents an integer of 0 to 4,

r is an integer from 0 to 8 inclusive.

When the copolymer includes the bulky fluorene group, the copolymer has heat resistance and rigid physical properties due to a rigid aromatic skeleton and can improve the durability, and the entanglement of the polymer chain In the entanglement, the hydrodynamic volume becomes large, and it can easily transfer the lithium ion.

According to one embodiment of the present application, in the above formulas A and B, at least one of X < _{1 >} and X < ₂ >

또는

일 수 있다.According to one embodiment of the present application, in the above Formulas A and B, at least one of X ₁ , X ₂ and X ₃ is

or

Lt; / RTI >

According to one embodiment of the present application, in formula (B), Y < ₁ > May be any one selected from the following structural formulas.

,

,

,

,

,

,

,

,

,

,

,

,

,

및

.

,

,

,

,

,

,

,

,

,

,

,

,

,

And

.

Wherein Q is -SO ₃ Li, -COOLi or -OLi and Q 'is hydrogen, -SO ₃ Li, -COOLi or -OLi.

According to one embodiment of the present application, the copolymer may further comprise a repeating unit represented by the following formula (C).

≪ RTI ID = 0.0 &

According to one embodiment of the present application, in the above formula (C), Z is a trivalent organic group.

According to one embodiment of the present application, the repeating unit of the above-mentioned formula (C) is a brancher, which serves to connect or crosslink the polymer chain. Depending on the number of repeating units of formula (C), branches may be formed on the chain, or the chains may be crosslinked with each other to form a net-like structure.

According to one embodiment of the present application, in the above formula (C), Z is a trivalent organic group and may be linked with additional repeating units in each of three directions to elongate the polymer chain.

According to one embodiment of the present application, the number of ion transfer functional groups, the molecular weight and the like can be controlled by using a braner which is a repeating unit of the above-mentioned formula (C), and mechanical properties can be enhanced.

According to an embodiment of the present application, when the number of repeating units of the repeating unit represented by the above formula (C) is k, k may be an integer of 1 to 300.

According to one embodiment of the present application, the repeating unit of formula (C) may be a polymer repeating unit constituting the main chain. For example, Z may be connected to at least one selected from X ₁ , X ₂ , X ₃ and Y ₁ to form one repeating unit. One repeating unit formed as described above may form a main chain. In this case, the number of repeating units is equal to k.

In the present specification, when two or more members selected from Z, X ₁ , X ₂ , X ₃ and Y ₁ are bonded, they each have a linking group of oxygen (-O-). The oxygen linkage is a linking group in which the compound escapes by condensation polymerization and remains in the chain. For example, when the dihalide-based monomer and the diol-based monomer are polymerized, HF is released and only oxygen (-O-) remains in the chain.

According to one embodiment of the present application, in the above formula (C), Z is represented by the following formula (C-1) or (C-2).

[Chemical formula C-1]

[Chemical formula C-2]

In the above formulas C-1 and C-2,

Z ₁ may be represented by any one of the following formulas (7) to (9).

(7)

[Chemical Formula 8]

[Chemical Formula 9]

In the above formulas (7) to (9)

L ₃ to L ₆ are the same or different and are each independently a direct bond, -O-, -CO- or -SO ₂ -

E ₁ to E ₇ are the same or different from each other, and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted amine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

c ', d', e 'and h' are the same or different and each independently an integer of 0 to 4,

f ', g' and i 'are the same as or different from each other and each independently an integer of 0 or more and 3 or less,

X ₄ and X ₅ are the same as or different from each other, and each independently is the same as defined in X ₃ or Y _{1 in} the above formula (B).

According to one embodiment of the present application, in the above formula (C), Z may be any one selected from the following formulas.

,

,

,

,

,

,

,

,

및

.

,

,

,

,

,

,

,

,

And

.

According to one embodiment of the present application, the repeating unit of formula (A) can be represented by the following structural formula.

In the above formula, m is the same as described above.

According to one embodiment of the present application, the repeating unit of the above formula (B) can be represented by the following structural formula.

,

,

,

,

In the above structural formulas, n is the same as described above.

According to one embodiment of the present application, the weight average molecular weight of the copolymer may be 100,000 or more and 1,000,000 or less. When the weight average molecular weight of the copolymer is within the above range, the solubility of a suitable copolymer can be maintained while having mechanical properties as a protective layer.

According to one embodiment of the present application, the protective layer may be provided on at least one surface of the electrode layer.

According to one embodiment of the present application, the protective layer may be provided on one surface of the electrode layer.

According to an embodiment of the present application, the protective layer may be provided on both sides of the electrode layer.

According to one embodiment of the present application, the protective layer may be provided to surround the electrode layer.

According to one embodiment of the present application, the thickness of the protective layer may be 0.01 to 50 탆, specifically 0.1 to 50 탆.

According to one embodiment of the present application, the lithium contained in the electrode layer can serve as an active material.

According to one embodiment of the present application, the lithium included in the electrode layer is lithium metal; Lithium metal alloy; Or a composite of lithium and at least one selected from the group consisting of coke, activated carbon, graphite, graphitized carbon, carbon nanotubes and carbon such as graphine; ≪ / RTI >

According to one embodiment of the present application, the lithium metal alloy may be an alloy of lithium and at least one selected from the group consisting of Al, Mg, Si, Sn, B and Fe.

According to one embodiment of the present application, the mass ratio of the metal other than lithium to the lithium metal alloy may be 0.1% to 50% of the lithium.

According to an embodiment of the present application, the electrode layer may further include at least one of a binder, a solvent, a conductive material, and a dispersant.

According to one embodiment of the present application, the lithium electrode is prepared by mixing and stirring a lithium-containing active material, a binder, a solvent, a conductive material, and a dispersing material produced by a general method to form a slurry, Followed by compression drying.

According to one embodiment of the present application, the collector may be formed of a foil or the like made of a combination of copper, nickel, etc., and alloys thereof. The negative electrode current collector may have fine irregularities on the surface thereof to increase the adhesive force of the negative electrode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

According to one embodiment of the present application, the binder is a component that assists in bonding between the negative electrode active material and the conductive material and bonding to the negative electrode collector, and includes polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated- Butadiene rubber, fluorine rubber, and various copolymers thereof.

According to one embodiment of the present application, the conductive material is a component for further improving the conductivity of the electrode active material. The conductive material is not particularly limited as long as the conductive material does not cause a chemical change in the battery and has conductivity. For example, Graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The present application also provides a lithium battery including the lithium electrode.

According to one embodiment of the present application, the lithium electrode is a cathode of a lithium battery.

Generally, a battery using lithium as a negative electrode is referred to as a lithium battery. The lithium battery may be a primary battery or a secondary battery.

According to one embodiment of the present application, the lithium battery is a lithium secondary battery. Specific examples thereof include a lithium secondary battery, a lithium polymer battery, a lithium sulfur battery, and a lithium air battery.

According to one embodiment of the present application, the lithium battery includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, and the negative electrode may be the lithium electrode.

According to one embodiment of the present application, when the lithium electrode is used as the cathode of the lithium battery, the surface on which the protection layer is provided in the electrode layer may be in the anode side direction.

According to one embodiment of the present application, the lithium battery includes a positive electrode and a negative electrode, the negative electrode is the lithium electrode, and the surface on which the protective layer is provided in the electrode layer may be in the positive electrode side direction. That is, the lithium battery does not include a separation membrane, and the protective layer of the lithium electrode may serve as a separation membrane.

When the lithium electrode according to one embodiment of the present application is used as a negative electrode of a lithium battery, it is possible to prevent the occurrence of battery shortage by suppressing the growth of lithium dendrite in the negative electrode during charging and discharging and further improve the life and stability of the battery .

According to an embodiment of the present application, the anode may be manufactured in such a manner that the cathode active material is coated on the cathode current collector according to a general method. LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , and Li (Ni _a Co _b Mn _c ) may be used as the positive electrode active material. O ₂ , where a, b and c are each a number from 0 to 1, a + b + c = 1, LiFePO ₄ or a mixture of one or more thereof. The positive electrode current collector may be a foil or the like made of a combination of aluminum, nickel, etc., and one or more of these alloys.

According to one embodiment of the present application, the separation membrane is not particularly limited and may be in the form of a porous membrane. Specifically, the separation membrane may be formed of polyethylene, polypropylene, other polyolefin-based membranes, or multilayer films thereof. Or a ceramic coating may be applied to the separation membrane.

The lithium battery according to one embodiment of the present application can be manufactured by a conventional method known in the art and can be manufactured by injecting an electrolyte into a cylindrical, square, or pouch-shaped outer shape assembled with the cathode, anode, have. The separation membrane may not be included.

Hereinafter, the present application will be described in more detail by way of examples. However, the following embodiments are intended to illustrate the present application, and the scope of the present application is not limited thereby.

<Preparation Example> Preparation of Lithium Ion Conducting Polymer

(Manufactured by BRANDER)

5 g (18.8 mmol) of 1,3,5-benzenetricarbonyltrichloride, 6.7 g (50.0 mmol) of aluminum chloride and 50 mL of distilled dichloromethane (DCM) were added to a 250 mL round- At 25 占 폚 for 30 minutes. Next, 20 mL of dichloromethane and 4.5 g (48.8 mmol) of fluorobenzene were added to a dropping funnel of 100 mL, and this fluorobenzene solution was added dropwise to the reaction product of the round flask. The reaction mixture was stirred for 4 hours under a nitrogen atmosphere, 20 mL of distilled water was added thereto, and the reaction mixture was further stirred for 12 hours or more. The reaction product was extracted with dichloromethane and the organic solvent was removed. The obtained crude product was recrystallized from ethanol to obtain a white branched copolymer [3,5-bis (4-fluorobenzoyl) phenyl] (4-fluorophenyl) methanone (yield: 70%). The structure of the above [3,5-bis (4-fluorobenzoyl) phenyl] (4-fluorophenyl) methanone was confirmed by 1H-NMR, 13C-NMR spectroscopy and elemental analysis. (Ppm) 8.24 (s, 3H), 7.96 (m, 6H), 7.46 (m, 6H)

(Manufacture of branched minor blocks)

After a dean-stark apparatus was connected to a 500 mL round flask, 17.238 g (79.00 mmol) of 4,4'-difluorobenzophenone, [3,5-bis (4-fluorobenzoyl) 24.512 g (69.92 mmol) of 9,9-bis (4-hydroxyphenyl) fluorene, 19.327 g (139.84 mmol) of potassium carbonate, 200 mL of methyl-2-pyrrolidone, and 120 mL of benzene were added. The reaction mixture was then stirred in an oil bath at 140 占 폚 under nitrogen for 4 hours to react the azotrope adsorbed on the molecular sieves of the Dean-Stark apparatus while the benzene was refluxed After the reaction mixture was completely removed with nitrogen, the reaction temperature was raised to 182 ° C, and 100 mL of N-methyl-2-pyrrolidone was further added thereto to carry out condensation polymerization for 12 hours. After the completion of the reaction, the temperature of the reaction product was reduced to 60 ° C, and about 200 mL of N-methyl-2-pyrrolidone in the reaction product was removed while a vacuum was applied and the temperature of the reaction product was raised to 120 ° C. Then, the temperature of the reaction mixture was reduced to room temperature, 300 mL of methyltetrahydrofuran (THF) was added to dilute the reaction product, the diluted reaction product was poured into 3 L of methanol to separate the copolymer from the solvent, (cake form) was dried in a vacuum oven at 80 캜 for 12 hours or more to prepare 34.8 g of a branched white minor block having a weight average molecular weight of 5,000 g / mol and a terminal group characterized by flourine elements.

(Production of polyarylene ether copolymer containing lithium sulfonate)

13.082 g (2.616 mmol) of the branched minor block prepared as described above, 10.162 g (46.572 mmol) of 4,4'-difluorobenzophenone, [3,5-bis (4-fluorobenzoyl) phenyl] (2.093 mmol) of lithium aluminum hydride, 11.945 g (52.328 mmol) of hydroquinone sulfonic acid lithium salt, 14.463 g (104.650 mmol) of potassium carbonate, 200 mL of dimethyl sulfoxide and 120 mL of benzene were added . The reaction mixture was then stirred in an oil bath at 140 占 폚 under nitrogen for 4 hours to react the azotrope adsorbed on the molecular sieves of the Dean-Stark apparatus while the benzene was refluxed After the reaction mixture was completely removed with nitrogen, the reaction temperature was elevated to 182 ° C, and 100 mL of dimethyl sulfoxide was further added thereto to conduct condensation polymerization for 12 hours. After completion of the reaction, 200 mL of dimethyl sulfoxide was added to dilute the reactant, and the diluted reaction product was poured into 3 L of methanol to separate the copolymer from the solvent. The resulting cake was filtered, Dried in an oven for 12 hours or longer to prepare a polyarylene ether copolymer containing lithium sulfonate in which branched and hydrophilic blocks were alternately chemically bonded. The weight average molecular weight of the copolymer was about 800,000.

<Comparative Example>

Cells were fabricated by using 40 ㎛ thick lithium metal as anode and cathode symmetric cells, PE (PolyEthylene) as separator, and TD2 (Ether system electrolyte) as electrolytic solution.

<Examples>

Except that a solution prepared by dispersing the lithium ion conductive polymer on one surface of a lithium metal used as a cathode was coated with a doctor blade and then dried at room temperature to form a protective layer, Respectively. At this time, the coating thickness of the protective layer was 10 mu m.

2 is a schematic view of a lithium electrode according to one embodiment of the present application including a conventional lithium electrode and a protective layer. For example, in the comparative example, the lithium electrode on the left side in FIG. 2 is used as a negative electrode, and the above embodiment can be explained as using the lithium electrode on the right side in FIG.

<Experimental Example>

The charge and discharge efficiencies of the cells prepared in the above Comparative Examples and Examples were measured under the charge and discharge conditions of C-rate: 0.4 C and DOD: 40%. The results are shown in FIG. 1 and Table 1.

Comparative Example Example Charging / discharging efficiency (%) 88 92.4

1 is a graph showing the performance of a cell manufactured according to the comparative example and the example of the present application.

As shown in FIG. 1 and Table 1, it can be seen that the lithium ion conductive polymer-coated embodiment exhibits about 4.5% higher efficiency than the comparative example.

Accordingly, the lithium battery including the lithium electrode according to one embodiment of the present application can exhibit high charge / discharge efficiency due to the protective layer including the lithium ion conductive polymer.

Claims (16)

An electrode layer containing lithium; And
And a lithium ion conductive polymer disposed on at least one side of the electrode layer and containing at least one functional group selected from -SO ₃ Li, -COOLi, and -OLi. The lithium electrode according to claim 1, wherein the lithium ion conductive polymer comprises a repeating unit represented by the following formula (D):
[Chemical Formula D]

In the above formula (D)
R is a substituted or unsubstituted hydrocarbon group selected from the group consisting of fluorine, oxygen, nitrogen and sulfur,
X is -SO ₃ Li, -COOLi or -OLi,
and y is 2 to 100,000. The lithium electrode according to claim 2, wherein the formula (D) is represented by the following formula (E):
(E)

In the above formula (E)
A is -OCF ₂ CF (CF ₃₎ -, or a bond directly,
k is an integer of 1 to 30,
s is an integer from 1 to 10,
and y is an integer of 2 to 100,000. The method of claim 2,
Wherein the repeating unit represented by the formula (D) has a weight average molecular weight of 500 to 1,000,000. The lithium electrode according to claim 1, wherein the lithium ion conductive polymer comprises a copolymer comprising a repeating unit represented by the following formula (A) and a repeating unit represented by the following formula (B):
(A)

[Chemical Formula B]

In the above Formulas A and B,
m and n represent the number of repeating units,
1? M? 500, 1? N? 500,
X ₁ , X ₂ and X ₃ are the same or different and each independently represents one of the following formulas (1) to (3)
[Chemical Formula 1]

(2)

(3)

In the above Chemical Formulas 1 to 3,
L ₁ is either a direct connection, -CZ ₂ Z ₃ -, and any of the substituted or unsubstituted monovalent fluorene unsubstituted fluorene group 2 -, -CO-, -O-, -S-, -SO 2 -, -SiZ 2 Z 3 One,
Z ₂ and Z ₃ are the same or different and are each independently any one of hydrogen, an alkyl group, a trifluoromethyl group (-CF ₃ ) and a phenyl group,
S ₁ to S ₅ are the same or different from each other, and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted amine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,
a, b, c, p and q are the same as or different from each other, each independently an integer of 0 or more and 4 or less,
p + q? 6,
a 'is an integer of 1 to 5,
In the formula (B), Y ₁ is represented by any one of the following formulas (4) to (6)
[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

In the above formulas 4 to 6,
L ₂ is a direct bond or any one selected from -CO-, -SO ₂ -, and a substituted or unsubstituted divalent fluorene group,
d, e, f, g and h are the same as or different from each other, and each independently an integer of 0 to 4,
f + g? 6,
b 'is an integer of 1 or more and 5 or less,
T ₁ to T ₅ are the same or different from each other, and at least one of them is independently at least one of -SO ₃ Li, -COOLi or -OLi, and the others are the same or different, and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted amine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group. The method of claim 5,
X ₁ , X ₂ and X ₃ are the same or different and each independently selected from the following structural formulas:

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

And

,
In the above formulas, R and R 'are the same as or different from each other, and each independently -NO ₂ or -CF ₃ . The method of claim 5,
Wherein Y &lt; _{1 &gt;} is any one selected from the following structural formulas:

,

,

,

,

,

,

,

,

,

,

,

,

,

And

,
In the above formula, Q is -SO ₃ Li, -COOLi or -OLi, Q 'is hydrogen, -SO ₃ Li, -COOLi or -OLi. The method of claim 5,
Wherein the copolymer further comprises a repeating unit represented by the following formula (C): &lt; EMI ID =
&Lt; RTI ID = 0.0 &

In the above formula (C), Z is a trivalent organic group. The method of claim 8,
Wherein Z is represented by the following formula (C-1) or (C-2):
[Chemical formula C-1]

[Chemical formula C-2]

In the above formulas C-1 and C-2,
Z ₁ is represented by any one of the following formulas (7) to (9)
(7)

[Chemical Formula 8]

[Chemical Formula 9]

In the above formulas (7) to (9)
L ₃ to L ₆ are the same or different and are each independently a direct bond, -O-, -CO- or -SO ₂ -
E ₁ to E ₇ are the same or different from each other, and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted amine group; A substituted or unsubstituted aryl group; A substituted or unsubstituted heteroaryl group; Or a substituted or unsubstituted fluorenyl group,
c ', d', e 'and h' are the same or different and each independently an integer of 0 to 4,
f ', g' and i 'are the same as or different from each other and each independently an integer of 0 or more and 3 or less,
X ₄ and X ₅ are each independently the same as defined for X ₃ or Y _{1 in} the above formula (B). The method of claim 8,
Wherein Z &lt; _{1 &gt;} is any one selected from the following structural formulas:

,

,

,

,

,

,

,

,

And

. The method of claim 5,
Wherein the weight average molecular weight of the copolymer is 100,000 or more and 1,000,000 or less. The lithium electrode according to claim 1, wherein the thickness of the protective layer is 0.01 to 50 탆. The lithium secondary battery according to claim 1, wherein the lithium contained in the electrode layer is lithium metal; Lithium metal alloy; Or a composite of lithium and at least one selected from the group consisting of coke, activated carbon, graphite, graphitized carbon, carbon nanotubes, graphine and carbon, And a lithium electrode. 14. The lithium electrode according to claim 13, wherein the lithium metal alloy is an alloy of lithium and at least one selected from the group consisting of Al, Mg, Si, Sn, B and Fe. A lithium battery comprising the lithium electrode according to any one of claims 1 to 14. 16. The lithium battery according to claim 15, wherein the lithium electrode is a cathode.

Images