KR101990609B1 - Lithium electrode and lithium secondary battery employing thereof - Google Patents

Abstract

The present invention relates to a lithium electrode and a lithium secondary battery comprising the same. More particularly, the present invention relates to a lithium secondary battery comprising an electrode protective layer formed on an electrode containing lithium, To a lithium secondary battery including a crosslinked polymer having a moiety derived from a chemical structure of a solvent and a lithium secondary battery comprising the electrode.
The electrode reduces the reaction between lithium and the electrolyte to reduce consumption of the electrolyte and lithium, thereby improving the life of the lithium secondary battery.

Description

[0001] The present invention relates to a lithium electrode and a lithium secondary battery including the lithium electrode,

The present invention relates to a lithium electrode having improved life characteristics by including an electrode protection layer on a surface thereof, and a lithium secondary battery including the same.

With the rapid development of the electronics, communications and computer industries, applications of energy storage technologies are expanding to camcorders, mobile phones, notebook PCs, and even electric vehicles. Accordingly, development of a small secondary battery that is light and long-lasting, and has high reliability and high performance is underway.

Lithium secondary batteries are attracting attention as a battery that satisfies these demands.

The lithium secondary battery has a structure in which an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode is laminated or wound, and the electrode assembly is embedded in a battery case, and a non- do. The lithium secondary battery produces electrical energy by oxidation and reduction reactions when lithium ions are inserted / removed from the positive electrode and the negative electrode.

The anode of the lithium secondary battery is used as an active material such as lithium metal or carbon, and the anode is used as an active material such as lithium oxide, transition metal oxide, metal chalcogenide compound, and conductive polymer.

The lithium used in the electrode, especially the lithium electrode, has high reactivity with the electrolyte component, and when the electrolyte component comes into contact with the lithium metal, a spontaneous reaction forms a film called a passivation layer. The protective film formed on the lithium surface during charging and discharging repeats destruction and formation. Therefore, when the battery is repetitively charged and discharged, the protective film component increases in the lithium negative electrode and the electrolyte is depleted. In addition, some of the reduced materials in the electrolyte cause side reactions with the lithium metal, thereby accelerating the consumption of lithium. As a result, the life of the battery is reduced.

Accordingly, various methods for stabilizing lithium have been proposed, and a method of forming a protective layer at a position in contact with the electrode has been proposed.

Korean Patent Registration No. 10-0578797 discloses that the stability of the lithium metal anode can be improved by using an additive such as alkyl acrylate capable of forming a polymer film on the surface of the anode by electrochemical reduction of the electrolyte solution.

In addition, the Republic of Korea Patent No. 10-0425585 call the lithium electrode surface, CH ₂ = CH-CO ₂ for - a _{(CH 2) 8 -CO 2 -CH} = protective crosslinked polymer films by using a di-acrylic monomer represented by CH ₂ Thereby improving the interfacial characteristics between the lithium electrode and the polymer electrolyte, thereby increasing the lifetime of the battery.

However, even when the polymer film or the crosslinked polymer protective film is used, the reaction between the electrolyte and the lithium electrode can not be satisfactorily suppressed.

Accordingly, Korean Patent Publication No. 2014-0036413 proposes a method of using an organic solvent inert to lithium as an electrolytic solution, but it is impossible to directly block the electrolytic solution from lithium even in this effort.

Korean Patent Registration No. 10-0578797, "Electrolyte for lithium metal battery and lithium metal battery containing same" Korean Patent Registration No. 10-0425585, "Lithium Polymer Secondary Battery with Crosslinked Polymer Protection Thin Film and Method for Manufacturing the same" Korea 2014-0036413, "Lithium battery"

In order to solve the above problem, the inventors of the present invention found that when the electrolyte and lithium can not be directly blocked, the contact between the electrolyte and lithium is accepted. As a result of conducting studies in order to delay the consumption of lithium as much as possible, It is possible to increase the life of the electrode by reducing the consumption of lithium by disposing a material having a molecular structure of a solvent as a protective layer capable of controlling the lithium interface between the lithium and the electrolyte. Respectively.

Accordingly, an object of the present invention is to provide an electrode for a lithium secondary battery having improved life characteristics.

Another object of the present invention is to provide a lithium secondary battery comprising the electrode for a lithium secondary battery.

In order to achieve the above object,

Electrode collector,

An electrode material mixture layer formed on one or both surfaces of the electrode current collector and containing lithium; And

And an electrode protection layer formed on the electrode mixture layer,

Wherein the electrode protection layer comprises a crosslinked polymer having a moiety derived from a chemical structure of an ether-based solvent having a reduction potential lower than a reduction potential of lithium.

The crosslinked polymer is characterized in that the ethylenically unsaturated monomer containing a moiety derived from the chemical structure of the ether-based solvent and the crosslinkable monomer are cross-linked.

The present invention also provides a lithium secondary battery including a separator interposed between a positive electrode, a negative electrode, and a positive electrode, and an electrolyte, wherein at least one of the positive electrode, the negative electrode, and both electrodes is a lithium secondary battery Thereby providing a battery.

The electrode for a lithium secondary battery according to the present invention suppresses the reaction between an electrode active material, particularly lithium and an electrolyte solvent, so that lithium consumption is reduced. The life characteristics of the lithium secondary battery employing such an electrode are improved.

Hereinafter, the present invention will be described in detail.

Lithium secondary batteries use lithium as an electrode active material. At this time, lithium is consumed by the contact between lithium and an electrolyte, side reactions occur, resulting in deterioration of the life. In order to control the reaction at the interface between lithium and the electrolyte, an electrode protecting layer is disposed therebetween. In the present invention, a material selected in consideration of the reduction potential of lithium and an electrolyte, It is used as a protective layer.

The electrode protecting layer proposed in the present invention includes a crosslinked polymer obtained by cross-linking an ethylenically unsaturated monomer containing a moiety derived from the chemical structure of an ether-based solvent and a crosslinking monomer.

The ethylenically unsaturated monomer as the first monomer constituting the crosslinked polymer is used for controlling between lithium and the electrolyte in relation to the standard reduction potential and the crosslinkable monomer as the second monomer is used to increase the ionic conductivity of the electrode protective layer and to improve the physical properties E.g., film strength, etc.).

The standard reduction potential is related to the ionization tendency to lose electrons, and the lower the number, the stronger this tendency. The standard reduction potential of lithium is -3.04 V, and when a material having a reduction potential lower than that is used, it has a lower ionization tendency than lithium, resulting in a lower reactivity with lithium.

As non-aqueous solvents, ether solvents, carbonate solvents and the like are mainly used. Among them, the ether solvent has a lower value than the standard reduction potential of lithium, so that lithium can be stabilized.

The ethereal solvent may be selected from the group consisting of tetrahydrofuran, ethylene oxide, 1,3-dioxolane, dimethoxyethane, 3,5-dimethylisoxazole, 2,5-dimethylfuran, furan, 4-methyl-1,3-dioxolane, tetraethylene glycol dimethyl ether (TEGDME) and the like are used. The structure of these ether solvents includes at least one oxygen (O) atom, wherein the structure derived from the following compound having two or more oxygen atoms, rather than a structure such as tetrahydrofuran, ethylene oxide or oxane, The desired properties can be achieved in the invention:

, 디메톡시에탄:

1,3-dioxolane:

, Dimethoxyethane:

4-methyl-1,3-dioxolane:

Tetraethylene glycol dimethyl ether (TEGDME):

That is, in the present invention, an ethylenically unsaturated monomer containing a chemical structure of an ether-based solvent as a first monomer in a molecular structure is designed so that the advantages of the ether-based solvent of lithium stabilization can be exhibited in the electrode protective layer, .

Specifically, the ethylenically unsaturated monomer as the first monomer is represented as follows:

[Chemical Formula 1]

A-B

(In the formula 1,

A is a moiety comprising an ethylenically unsaturated polymerizable group,

B is a moiety derived from the chemical structure of the ether-based solvent.

In the above formula (1), A includes, but is not limited to, unsaturated alkenes, vinyl ethers, or acrylate groups or methacrylate groups. Examples of the polymerizable groups are C1 to C6 linear alkenes, C1 to C6 linear vinyl ethers, and C2 to C8 linear alkyl acryl esters or C2 to C8 cyclic alkyl acrylates. Examples of preferred polymerizable groups are a vinyl group, an allyl group, an acryloyl group or a methacryloyl group.

In addition, B is an alkyl group of C1 ~ C4 substituted or unsubstituted _{dioxolanyl, -O - [- (CH 2} ) n -O] m -R 3 (R 3 = alkyl group of C1 ~ C4, 1≤n≤ 5) each include a functional group which is linear or branched to each other, more preferably includes the following functional groups and the like:

This ethylenically unsaturated monomer is polymerized by the polymerizable portion (A) when applied as an electrode protective layer, wherein the portion (B) derived from the chemical structure of the etheric solvent is present in the side chain of the polymer forming the electrode protective layer . Thus, since the portion B includes the chemical structure of the ether-based solvent having a lower reduction potential than lithium in the molecular structure, the effect of the conventional ether-based solvent, that is, stabilization of lithium and reduction of the reaction between lithium and the reduced electrolyte An effect of delaying consumption of lithium can be obtained. As a result, the life of the lithium electrode can be prolonged, and at the same time, the life of the lithium secondary battery can be increased.

When the above-mentioned ethylenic unsaturated monomer is polymerized and applied as an electrode protective layer, the above effect can not be secured by using only this monomer. That is, when a homopolymer of an ethylenically unsaturated monomer is used as an electrode protective layer, it is easily swelled by an electrolyte or the like and can not contribute to the stabilization of the lithium electrode. Therefore, in the present invention, a crosslinkable monomer is used as a second monomer together with an ethylenically unsaturated monomer as a first monomer so as to form a crosslinked network structure of the electrode protecting layer. Such a crosslinked network structure increases the strength of the coating film, solves the swelling problem, and improves the ion conductivity of lithium ions.

The crosslinking monomer as the second monomer is a polyfunctional monomer having at least two, preferably from 2 to 8, preferably from 2 to 6, ethylenically unsaturated bonds, and is preferably a polyfunctional monomer having a molecular And those having an ethylene oxide functional group in the structure are used.

For example, the crosslinkable monomer may be selected from the group consisting of 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di , Neopentylglycol adipate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (Meth) acrylate, neopentyl glycol-modified trimethylpropane di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, dimethylol dicyclopentanedi Bifunctional acrylates such as acrylates and ethers; (Meth) acrylates such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; Pentafunctional acrylates such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And 6-functional acrylates such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate, but are not limited thereto.

An electrode protective layer of a crosslinked network structure is formed by crosslinking polymerization of an ethylenically unsaturated monomer as a first monomer and a crosslinking monomer as a second monomer, Due to the moiety, is located between the lithium and the electrolytic solution, the consumption of lithium can be suppressed even if the lithium and the electrolyte are in contact with each other, and the side reaction between lithium and the electrolytic solution is suppressed. In addition, by having a structurally crosslinked network structure, it is possible to physically suppress the generation of lithium dendrite on the surface of the conventional electrode by increasing the strength of the electrode protection layer, and to prevent the electrolyte solution from penetrating into the polymer membrane to dissolve the polymer membrane Can be effectively prevented.

The thickness of the electrode protection layer is not limited to the present invention, and may be within the range of 10 nm to 10 [mu] m, for example, while ensuring the above effect but not raising the internal resistance of the battery. If the thickness is less than the above range, the protective layer can not be performed. On the other hand, when the thickness exceeds the above range, stable interfacial characteristics can be imparted, but the initial interfacial resistance is increased, .

The preparation of the electrode protection layer according to the present invention is not particularly limited. For example, an ethylenically unsaturated monomer as a first monomer, a crosslinking monomer as a second monomer, and an initiator for crosslinking polymerization are added to a solvent, And performing a curing reaction.

At this time, it is necessary to limit the content so as to maintain the strength sufficient to serve as the electrode protective layer. Preferably, 5 to 50 parts by weight of a crosslinkable monomer as a second monomer is used for 100 parts by weight of the ethylenic unsaturated monomer as the first monomer. If the content is less than the above range, the effect described above can not be obtained. On the other hand, if the content exceeds the above range, the strength of the electrode protective layer excessively increases and the density increases, The battery performance may be deteriorated.

Any solvent may be used as long as it can dissolve the ethylenic unsaturated monomer as the first monomer and the crosslinkable monomer as the second monomer, and preferably a non-aqueous organic solvent is used. The non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move, and known carbonate-based, ester-based, ether-based, ketone-based, alcohol-based or aprotic solvents can be used. Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, gamma-butyrolactone, -Dimethoxyethane, 1,2-diethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, 4-methyl- The organic solvent may be selected from the group consisting of diethyl ether, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivative, An aprotic organic solvent such as dimethyl-2-imidazolidinone, a propylene carbonate derivative, a tetrahydrofuran derivative, ether, methyl pyrophosphate, ethyl propionate and the like can be used.

The coating may be a method used in conventional wet processes such as spin coating, spray coating, doctor blade coating, dip coating and the like. However, it may be preferable to perform spin coating for uniformity of the coating and ease of control of the coating thickness.

If necessary, drying after coating is carried out. The drying can be appropriately selected at a temperature higher than the boiling point of the solvent and at a temperature lower than the Tg of the polymeric material of the electrode protective layer. The solvent remaining on the surface of lithium can be removed through the drying process and the adhesion of the electrode protective layer can be improved.

The curing reaction is carried out by UV or heat, and crosslinking takes place through this curing reaction.

The initiator varies depending on the UV / thermal polymerization method, and any known photoinitiator or thermal initiator can be used. Examples of the photoinitiator include benzoin, benzoin ethyl ether, benzoin isobutyl ether, alpha methyl benzoin ethyl ether, benzoin phenyl ether, acetophenone, dimethoxyphenylacetophenone, 2,2-diethoxyacetophenone , 1,1-dichloroacetophenone, trichloroacetophenone, benzophenone, p-chlorobenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2- 2-methyl anthraquinone, 2-methyl-1- (4-methylthiophenyl) -morpholinopropanone-2-methylpropiophenone, benzyl benzoate, benzoyl benzoate, anthraquinone, 2- (Darocure 1173 from CIba Geigy), Darocure 1116, Irgacure 907, 2-benzyl-2-dimethylamino-1- ( 4-morpholinophenyl) -butanone-1,1-hydroxycyclohexyl phenyl ketone (Irgacure 184 from CIba Geigy), microclerketone, benzyl dimethyl ketal, (-OO-) group, and the like may be used. Examples of the initiator include a peroxide (-OO-) group such as benzene, benzene, toluene, isopropyl thioxanthone, chlorothioxanthone, benzyl, benzyldisulfide, butanedione, carbazole, fluorenone, Di-tert-butyl peroxide, cumyl hydroperoxide, and the like can be used. As the azo-based compound (-N = N-) -based azobisisobutyronitrile , Azobisisobalonitrile, and the like can be used.

The content of the initiator is not particularly limited and preferably ranges not affecting the properties of the electrode protective layer and the electrode and electrolyte. For example, the content of the initiator is in the range of 1 to 15 parts by weight relative to 100 parts by weight of the total amount of monomers use.

Other specific methods and compositions are not mentioned herein and may be selected by the person skilled in the art.

The above-mentioned electrode protecting layer according to the present invention can be preferably introduced into an electrode for a lithium secondary battery.

The electrode for a lithium secondary battery includes an electrode current collector and an electrode mixture layer formed on one or both surfaces of the electrode current collector and including lithium. At this time, the above-described electrode protection layer is disposed on the electrode mixture layer, thereby suppressing the side reaction between lithium and the electrolyte, thereby delaying consumption of lithium.

The electrode may be an anode, a cathode, or both electrodes.

The electrode current collector is a positive electrode current collector when the electrode is a positive electrode, and is a negative electrode current collector when the electrode is a negative electrode.

The positive electrode current collector is not particularly limited as long as it has high conductivity without causing a chemical change in the battery. For example, carbon, nickel , Titanium, silver, or the like may be used.

The negative electrode current collector is not particularly limited as long as it has electrical conductivity without causing chemical change in the battery. For example, carbon, stainless steel, aluminum, nickel, titanium, sintered carbon, , Nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. The negative electrode current collector may be formed in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven fabric, and the like having fine irregularities on its surface.

When the electrode according to the present invention is an anode, the electrode mixture layer includes a cathode active material, and in the case of a cathode, includes an anode active material. At this time, each of the electrode active materials can be any active material applied to conventional electrodes, and is not particularly limited in the present invention.

The cathode active material may be varied depending on the use of the lithium secondary battery, and a known material is used for the specific composition. For example, any lithium transition metal oxide selected from the group consisting of lithium cobalt oxide, lithium manganese oxide, lithium copper oxide, lithium nickel oxide and lithium manganese composite oxide, and lithium-nickel-manganese- More specifically, lithium manganese oxides such as Li _{1 + x} Mn _{2 - x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ and LiMnO ₂ ; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; Lithium nickel oxide represented by LiNi _{1 - x} M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga and x = 0.01 to 0.3); LiMn _{2 - x} MxO ₂ (where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 to 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni , Cu or Zn) of lithium manganese complex oxide, Li (Ni _a Co _b Mn _c expressed in), O ₂ (where, 0 <a <1, 0 <b <1, 0 <c <1, a + b + c = 1), Fe ₂ (MoO ₄ ) ₃ ; Sulfur element, disulfide compound, organosulfur compound and carbon-sulfur polymer ((C ₂ S _x ) _n : x = 2.5 to 50, n≥2); Graphite materials; Carbon black based materials such as Super-P, Denka black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black and carbon black; Carbon derivatives such as fullerene; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; And conductive polymers such as polyaniline, polythiophene, polyacetylene, and polypyrrole; And a form in which a catalyst such as Pt or Ru is supported on the porous carbon support, but the present invention is not limited thereto.

The negative electrode active material may be selected from the group consisting of lithium metal, a lithium alloy, a lithium metal composite oxide, a lithium-containing titanium composite oxide (LTO), and combinations thereof. The lithium alloy may be an alloy of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al and Sn. The lithium metal composite oxide is any one of metal (Me) oxides (MeO _x ) selected from the group consisting of lithium and Si, Sn, Zn, Mg, Cd, Ce, Ni and Fe. For example, LixFe ₂ O ₃ 0 = x = 1) or LixWO ₂ (0 < x = 1).

In addition to this, the negative electrode active material is SnxMe _{1 - x} Me _'y O _z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, of the periodic table Group 1, Group 2, Group 3 element, Halogen; 0 < x = 1; 1 = y = 3; 1 = z = 8); _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO2 2, Bi 2 O 3, Bi 2 O 4 , and Bi ₂ O ₅ and the like, and carbonaceous anode active materials such as crystalline carbon, amorphous carbon or carbon composite may be used alone or in combination of two or more.

At this time, the electrode mixture layer may further include a binder resin, a conductive material, a filler, and other additives.

The binder resin is used for bonding between the electrode active material and the conductive material and bonding to the current collector. Examples of such a binder resin include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetra Examples thereof include fluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber and various copolymers thereof.

The conductive material is used to further improve the conductivity of the electrode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, 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 whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Polyphenylene derivatives and the like can be used.

The filler is optionally used as a component for suppressing the expansion of the electrode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The production of the electrode for a lithium secondary battery according to the present invention is not particularly limited and follows a general electrode manufacturing process.

For example, the electrode mixture layer and the electrode protection layer are sequentially stacked on the electrode current collector.

In this case, the electrode material mixture layer may be prepared in the form of a lithium metal foil in the case of a lithium metal electrode or a form in which a lithium metal powder is coated on a support.

The present invention also provides a lithium secondary battery comprising a positive electrode, a negative electrode, a separator interposed between both electrodes, and an electrolyte, wherein the positive electrode, the negative electrode or both electrodes are the above-described electrodes.

The lithium secondary battery can extend the lifetime of the lithium secondary battery by preventing consumption of lithium due to the electrode protection layer formed in the electrode and suppressing or minimizing the side reaction between lithium and the electrolyte.

Preferably, the lithium secondary battery according to the present invention may be a lithium metal battery in which the anode is lithium metal.

At this time, the separator may be formed of a porous substrate. The porous substrate may be any porous substrate commonly used in an electrochemical device. For example, a polyolefin porous film or a nonwoven fabric may be used. It is not.

The separator may be formed of a material selected from the group consisting of polyethylene, polypropylene, polybutylene, polypentene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, A porous substrate made of any one selected from the group consisting of polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalate, or a mixture of two or more thereof.

The electrolyte solution of the lithium secondary battery is a lithium salt-containing electrolyte, which may be an aqueous or non-aqueous non-aqueous electrolyte, preferably a non-aqueous electrolyte comprising an organic solvent electrolyte and a lithium salt. An organic solid electrolyte or an inorganic solid electrolyte, but the present invention is not limited thereto.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, gamma-butyrolactone, -Dimethoxyethane, 1,2-diethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, 4-methyl- The organic solvent may be selected from the group consisting of diethyl ether, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivative, Dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

As the non-aqueous solvent, an ether-based solvent is used to resemble the electrode protecting layer of the present invention. Examples thereof include tetrahydrofuran, ethylene oxide, 1,3-dioxolane, 3,5-dimethylisoxazole, Dimethylfuran, furan, 2-methylfuran, 1,4-oxane, 4-methyl dioxolane and the like are used

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, LiSCN, LiC (CF 3 SO 2) 3, (CF 3 SO 2) 2 NLi, (FSO 2) 2 NLi, chloroborane lithium , Lower aliphatic carboxylic acid lithium, lithium 4-phenylborate, imide and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

For the purpose of improving charge / discharge characteristics, flame retardancy, etc., non-aqueous electrolytes may be used in the form of, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

The lithium secondary battery according to the present invention can be laminated, stacked, and folded in addition to winding, which is a general process. The battery case may have a cylindrical shape, a square shape, a pouch shape, a coin shape, or the like.

Claims (10)

Electrode collector,
An electrode material mixture layer formed on one or both surfaces of the electrode current collector and containing lithium; And
And an electrode protection layer formed on the electrode mixture layer,
Wherein the electrode protective layer comprises a crosslinked polymer having a moiety derived from a chemical structure of an ether-based solvent having a reducing potential lower than a reduction potential of lithium,
Wherein the crosslinking polymer is crosslinked with an ethylenically unsaturated monomer containing a moiety derived from a chemical structure of an ether-based solvent and a crosslinking monomer. delete The method according to claim 1,
Wherein the ethylenically unsaturated monomer is represented by the following Formula 1:
[Chemical Formula 1]
AB
(In the formula 1,
A is a moiety comprising an ethylenically unsaturated polymerizable group,
B is a moiety derived from the chemical structure of the ether-based solvent. The method of claim 3,
Wherein the ether solvent is 1,3-dioxolane, dimethoxyethane, 4-methyl-1,3-dioxolane, or tetraethylene glycol dimethyl ether (TEGDME). The method according to claim 1,
The crosslinkable monomer may be at least one selected from the group consisting of 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate, neopentylglycol adipate di Acrylate, tricyclodecane dimethanol (meth) acrylate, dimethylol dicyclopentanedi (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol-modified trimethylpropane di A bifunctional acrylate; (Meth) acrylates such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional acrylate including modified trimethylolpropane tri (meth) acrylate; Tetrafunctional acrylates of diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; Pentafunctional acrylates of propionic acid-modified dipentaerythritol penta (meth) acrylate; And 6-functional acrylates such as dipentaerythritol hexa (meth) acrylate or caprolactone-modified dipentaerythritol hexa (meth) acrylate; And a combination thereof. The electrode for a lithium secondary battery according to claim 1, The method according to claim 1,
Wherein the electrode protection layer has a thickness of 10 nm to 10 占 퐉. The method according to claim 1,
Wherein the electrode is an anode, a cathode, or both electrodes of a lithium secondary battery. The method according to claim 1,
Wherein the electrode is a cathode for a lithium metal battery. A lithium secondary battery comprising a positive electrode, a negative electrode, a separator interposed between both electrodes and an electrolyte,
The lithium secondary battery according to claim 1, wherein one of the positive electrode, the negative electrode, and both electrodes comprises the electrode for a lithium secondary battery. 10. The method of claim 9,
Wherein the lithium secondary battery is a lithium metal battery.