KR20130117715A - Electrode comprising polyolefin binder and lithium secondary battery comprising the same - Google Patents

Abstract

PURPOSE: An electrode as an electrode active material is provided to decrease a side reaction due to moisture and show an excellent adhesion with a small quantity which does not play as a resistance by using an electrode active material with no volume expansion during a charging and discharging process. CONSTITUTION: An electrode for a secondary battery comprises: an electrode current collector; and an electrode adhesive layer including the lithiated metal oxide formed on the electrode current collector. The binder comprises a polyolefin-group binder. The electrode adhesive layer contains a conductive material which is greater than 0.5 weight% and less than 3 weight% based on the total weight of the electrode material. The content of the polyolefin-group binder is greater than 2.0 weight% and less than 5.5 weight% based on the total weight of the electrode material.

Description

Electrode comprising a polyolefin-based binder and a lithium secondary battery comprising the same {Electrode Comprising Polyolefin Binder and Lithium Secondary Battery Comprising The Same}

The present invention relates to a secondary battery capable of repeated charging and discharging and an electrode constituting the secondary battery.

The increase in the price of energy sources due to the depletion of fossil fuels, the increase of interest in environmental pollution, and the demand for environmentally friendly alternative energy sources are becoming indispensable factors for future life. Various researches on power generation technologies such as nuclear power, solar power, wind power, and tidal power have been continuing, and electric power storage devices for more efficient use of such generated energy have also been attracting much attention.

Particularly, in the case of a lithium secondary battery, the demand for an energy source is rapidly increasing due to an increase in technology development and demand for a mobile device. Recently, the use of a lithium secondary battery as a power source for an electric vehicle (EV) and a hybrid electric vehicle , And the area of use is also expanding for applications such as power assisted power supply through gridization.

The binder plays an important role in mechanically stabilizing the electrode.

The electrode expands and contracts repeatedly according to charging and discharging of the battery. When such deformation occurs, the bonding between the active material or the conductive material is loosened and the contact resistance between particles increases. As a result, ohmic resistance of an electrode rises and battery characteristic falls.

These problems are caused by a decrease in the mechanical stability of the electrode can be solved by the use of a binder.

However, the use of excess binder not only reduces the electrode active material ratio but also causes the binder itself to act as a resistive element in the electrode, thereby reducing the performance of the battery. In addition, due to side reaction with the electrolyte, there is a problem that the capacity reduction and the cell resistance increase during the high temperature storage is accelerated.

On the other hand, insufficient adhesive force causes an electrode peeling phenomenon in a process such as electrode drying and pressing to increase the electrode failure rate. In addition, peeling of the electrode may occur due to an external impact, which may adversely affect the stability of the battery, such as life characteristics.

Therefore, there is a need for an electrode design capable of implementing effective adhesion and performance by differentiating the type and content of the binder according to the characteristics of the electrode active material.

The present invention is to provide an electrode including a polyolefin-based binder and a conductive material within a predetermined content range and a lithium secondary battery comprising the same.

According to the present invention,

An electrode current collector transferring electrons between the external conductor and the electrode active material; And

An electrode mixture layer formed on the electrode current collector and including a lithium metal oxide and a binder for occluding and desorbing lithium ions;

The binder provides a secondary battery electrode including a polyolefin-based binder.

The content of the polyolefin-based binder may be in the range of more than 2.0% by weight to less than 5.5% by weight relative to the total weight of the electrode mixture.

When the content of the polyolefin-based binder is 2.0% by weight or less, the increase in resistance is accelerated due to low adhesion, and in the case of 5.5% by weight or more, there is a problem of accelerating resistance due to side reaction with the electrolyte during high temperature storage.

The electrode mixture layer is in the range of more than 0.5% to less than 3% by weight, in the range of at least 1% and less than 3% by weight, in the range of at least 2% by weight and less than 3% by weight relative to the total weight of the electrode mixture. In may further include a conductive material.

Referring to the following experimental example, when the content of the conductive material is more than 3% by weight, even when increasing the content of the binder it can be seen that there is no significant difference in the initial resistance and the resistance increase rate after high temperature storage. However, when the content of the binder is more than 5.5% by weight relative to the total weight of the electrode mixture, it can be seen that the resistance increase rate after the initial resistance and the high temperature resistance is relatively increased.

Since the oxides of the following formulas (1) to (4) do not have a great degree of volume expansion during charge and discharge, the electronic conductivity can be maintained while exhibiting excellent adhesion within the above range.

The present invention also provides a lithium secondary battery having a structure in which an electrode assembly having a structure in which a polymer film is interposed between a cathode, an anode, and a cathode and an anode is housed in a battery case and sealed. The lithium secondary battery may include a lithium salt-containing non-aqueous electrolyte.

The lithium secondary battery may be a lithium ion battery, may be a lithium ion polymer battery, may be a lithium polymer battery.

The lithium secondary battery may include an oxide of formula (1) as a negative electrode active material, and may include an oxide of formula (3) as a positive electrode active material.

The positive electrode or the negative electrode may be manufactured by a manufacturing method including the following processes.

Electrode manufacturing method,

Preparing a binder solution by dispersing or dissolving the binder in a solvent;

Preparing an electrode mixture slurry by mixing the binder solution with an electrode active material and a conductive material;

Coating the electrode mixture slurry on a current collector;

Drying the electrode; And

Compressing the electrode to a constant thickness.

In some cases, the method may further include drying the rolled electrode.

The binder solution manufacturing process is a process of preparing a binder solution by dispersing or dissolving a binder in a solvent.

The binder may include a polyolefin binder.

The binder including the polyolefin-based binder may be a halogen-substituted or unsubstituted polyolefin-based compound.

The polyolefin-based binder is made of polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), polyvinyl chloride (PVC) It may be one kind or two or more kinds selected from the group. However, it is not limited only to these.

The binder may further include all binders known in the art, and specifically, carboxy methyl cellulose, silane, ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, polyethylene glycol, polyvinyl alcohol, acrylic air Coalescing and the like.

The solvent may be selectively used according to the type of the binder. For example, an organic solvent such as isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, water, and the like may be used.

Since lithium metal oxide of the following general formula (1) has a property of absorbing moisture, in particular, it is preferable to use a binder dissolved in an organic solvent in order to minimize side reactions caused by moisture.

In one specific embodiment of the present invention, a binder solution may be prepared by dispersing / dissolving PVdF in N-methyl pyrrolidone (NMP).

An electrode mixture slurry may be prepared by mixing / dispersing an electrode active material and a conductive material in the binder solution. The electrode mixture slurry thus prepared may be transferred to a storage tank and stored until the coating process. In the said storage tank, in order to prevent an electrode mixture slurry from hardening, an electrode mixture slurry can be stirred continuously.

The electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + y} Mn _2-y O ₄ (where y 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 ; Formula _{LiNi 1-y M y O 2} ( where, the M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, y = 0.01 ~ 0.3 Im) Ni site type lithium nickel oxide which is represented by; Formula LiMn _2-y M _y O ₂ , wherein M = Co, Ni, Fe, Cr, Zn or Ta and y = 0.01 to 0.1, or Li ₂ Mn ₃ MO ₈ , where M = Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Carbon such as Fe ₂ (MoO ₄ ) ₃ , non-graphitizable carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x < Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{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, GeO 2, Bi 2 O 3, Bi 2 O 4, Bi ₂ O ₅ and the like; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like, but are not limited to these.

In a non-limiting example of the present invention, the electrode active material may include lithium metal oxide, and the lithium metal oxide may be preferably represented by the following formula (1).

Li _a M ' _b O _4-c A _c (1)

In the above formula, M 'is at least one element selected from the group consisting of Ti, Sn, Cu, Pb, Sb, Zn, Fe, In, Al and Zr;

a and b are 0.1? a? 4; Is determined according to the oxidation number of M 'in the range of 0.2? B? 4;

c is determined according to the oxidation number in the range of 0? c <0.2;

A is one or more of an anion of -1 or -2.

The oxide of Formula (1) may be represented by the following Formula (2).

Li _a Ti _b O ₄ (2)

In the above formula, 0.5? A? 3, 1? B? 2.5.

The lithium metal oxide may be Li _0.8 Ti _2.2 O ₄ , Li _2.67 Ti _1.33 O ₄ , LiTi ₂ O ₄ , Li _1.33 Ti _1.67 O ₄ , Li _1.14 Ti _1.71 O _4, or the like. However, it is not limited only to these.

In a non-limiting embodiment of the present invention, the lithium metal oxide may be Li _1.33 Ti _1.67 O ₄ or LiTi ₂ O ₄ . Li _1.33 Ti _1.67 O ₄ has a spinel structure with little change in crystal structure during charge and discharge and excellent reversibility.

The lithium metal oxide can be produced by a production method known in the art, for example, can be produced by a solid phase method, hydrothermal method, sol-gel method and the like. A detailed description thereof will be omitted.

The lithium metal oxide may be in the form of secondary particles in which primary particles are aggregated.

The particle diameter of the secondary particles may be 200 nm to 30 ㎛.

If the particle size of the secondary particles is less than 200 nm, a decrease in the adhesive force in the negative electrode manufacturing process. Complementing this requires the use of more binders, which is undesirable in terms of energy density. If the particle diameter of the secondary particles is more than 30 μm, the diffusion rate of lithium ions is low, and thus it is difficult to realize high output, which is not preferable.

In addition, in a non-limiting embodiment of the present invention, the electrode active material may include a lithium metal oxide having a spinel structure represented by the following formula (3).

Li _x M _y Mn _2-y O _4-z A _z (3)

Wherein 0 < y < 2, 0 z < 0.2,

M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, ;

A is one or more of an anion of -1 or -2.

The maximum substitution amount of A may be less than 0.2 mol%, and in a specific embodiment of the present invention, A may be at least one anion selected from the group consisting of halogen, S and N, such as F, Cl, Br, and I.

By substituting these anions, the binding force with the transition metal is improved and the structural transition of the compound is prevented, so that the lifetime of the battery can be improved. On the other hand, if the amount of substitution of the anion A is too large (t ≧ 0.2), it is not preferable because the life characteristics are lowered due to the incomplete crystal structure.

Specifically, the oxide of Formula (3) may be a lithium metal oxide represented by the following Formula (4).

Li _x Ni _y Mn _2-y O ₄ (4)

In the above formula, 0.9? X? 1.2 and 0.4? Y? 0.5.

More specifically, the lithium metal oxide may be LiNi _0.5 Mn _1.5 O ₄ or LiNi _0.4 Mn _1.6 O ₄ .

The conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery. Examples of the conductive material include graphite such as natural graphite and 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 whiskeys 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.

Fillers and the like may be optionally added to the electrode mixture slurry as necessary.

The filler is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, etc. can be used.

The coating of the electrode mixture slurry on a current collector is a process of coating the electrode mixture slurry on a current collector in a predetermined pattern and a predetermined thickness by passing through a coater head.

The method of coating the electrode mixture slurry on the current collector, the electrode slurry may be distributed on the current collector and uniformly dispersed using a doctor blade, die casting, comma coating ( comma coating, screen printing, and the like. In addition, the electrode mixture slurry may be bonded to the current collector by pressing or lamination after molding on a separate substrate.

The current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, the surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver, and the like, aluminum-cadmium alloy, and the like can be used. The positive electrode current collector may be formed into various shapes such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven fabric, or the like by forming fine irregularities on the surface to enhance the bonding force of the positive electrode active material. Specifically, the positive electrode current collector may be a metal current collector including aluminum, and the negative electrode current collector may be a metal current collector including copper. The electrode current collector may be a metal foil, and may be an aluminum (Al) foil or a copper (Cu) foil.

The drying process is a process of removing the solvent and water in the slurry to dry the slurry coated on the metal current collector, in a specific embodiment, is dried within 1 day in a vacuum oven of 50 to 200 ℃.

After the drying process, a cooling process may be further included, and the cooling process may be slow cooling to room temperature so that the recrystallized structure of the binder is well formed.

In order to increase the capacity density of the electrode after the coating process and to increase the adhesion between the current collector and the active materials, the electrode may be compressed into a desired thickness by passing it between two hot-rolled rolls. This process is called a rolling process.

Before passing the electrode between two hot heated rolls, the electrode can be preheated. The preheating process is a process of preheating the electrode before it is introduced into the roll in order to increase the compression effect of the electrode.

The electrode after the rolling process is completed as described above, may be dried within a day in a vacuum oven at 50 to 200 ℃ as a range satisfying the temperature of the melting point or more of the binder. The rolled electrode may be cut to a constant length and then dried.

After the drying process, a cooling process may be further included, and the cooling process may be slow cooling to room temperature so that the recrystallized structure of the binder is well formed.

The polymer membrane is a separator that separates between the positive electrode and the negative electrode. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as the separator.

As the separator, an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m.

Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like; Kraft paper and the like are used. Representative examples currently on the market include the Celgard ^R 2400, 2300 (from Hoechest Celanese Corp.), polypropylene separator (from Ube Industries Ltd. or Pall RAI), and polyethylene series (from Tonen or Entek).

In some cases, a gel polymer electrolyte may be coated on the separation membrane to increase the stability of the cell. Representative examples of such a gel polymer include polyethylene oxide, polyvinylidene fluoride, and polyacrylonitrile.

The electrode assembly may include a jelly-roll electrode assembly (or wound electrode assembly), a stacked electrode assembly (or a stacked electrode assembly), or a stack & folding electrode assembly having a structure known in the art.

In the present specification, the stack & folding type electrode assembly is a method of folding or winding a separator sheet after arranging unit cells having a structure in which a separator is interposed between an anode and a cathode on a separator sheet. It can be understood as a concept including a stack & folding type electrode assembly to be manufactured.

In addition, the electrode assembly may include an electrode assembly having a structure in which any one of an anode and a cathode is laminated by a method such as thermal fusion in a state in which a structure is interposed between the separators.

As the non-aqueous electrolyte, a non-aqueous electrolyte, an organic solid electrolyte, an inorganic solid electrolyte, and the like are used.

Examples of the nonaqueous electrolyte include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate , Gamma -butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, Diethyl ether, formamide, dimethyl formamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane A non-protonic organic solvent such as an ether, a methyl pyrophosphate, or an ethyl propionate is used as the solvent, a sulfone, a methyl sulfolane, a 1,3-dimethyl-2-imidazolidinone, a propylene carbonate derivative, a tetrahydrofuran derivative, .

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.

As the inorganic solid electrolyte, for example, 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, sulfates, and the like of Li, such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may be 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, chloroborane lithium, lower aliphatic carboxylic acid lithium, 4-phenylborate, imide, and the like can be used.

For the purpose of improving the charge / discharge characteristics and the flame retardancy, the electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (fluoro-ethylene carbonate, PRS (propene sultone), FPC (fluoro-propylene carbonate), and the like.

Lithium secondary battery according to the present invention, after storage for 3 weeks at 60 ℃ as SOC 100, the measured capacity retention rate may be in the range of 85% or more and less than 100%, and at the same time the resistance increase rate is from 100% or more of the initial capacity It may be in the range of less than 135%.

The lithium secondary battery according to the present invention can be used not only in a battery cell used as a power source of a small device but also as a unit cell in a middle- or large-sized battery module including a plurality of battery cells.

Also, the present invention provides a battery pack including the battery module as a power source of a middle- or large-sized device, wherein the middle- or large-sized device is an electric vehicle (EV), a hybrid electric vehicle (HEV) An electric vehicle including a plug-in hybrid electric vehicle (PHEV), a power storage device, and the like, but the present invention is not limited thereto.

The structure of the battery module and the battery pack and the method of manufacturing the battery module and the battery pack are well known in the art, so a detailed description thereof will be omitted herein.

Since the electrode according to the present invention includes a polyolefin-based binder dissolved in an organic solvent, when a material having high moisture hygroscopicity is used as the electrode active material, side reactions due to moisture can be minimized as compared to the aqueous binder.

In addition, in the case of using the electrode active material without volume expansion during charge and discharge as the electrode active paper, it is possible to exhibit excellent binding strength even in a small amount that does not act as a resistance.

Lithium secondary battery comprising an electrode according to the present invention, since it comprises a polyolefin-based binder in the content range of more than 2.0% by weight to less than 5.5% by weight relative to the total weight of the electrode mixture, exhibits excellent high temperature storage characteristics There is this.

1 is a graph comparing the high temperature storage characteristics of non-limiting examples and comparative examples of the present invention.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

&Lt; Example 1 >

LiNi _0.5 Mn _1.5 O ₄ : Super-P: PVdF amount was measured to be 88.5: 8.5: 3, and then mixed in NMP to mix a positive electrode slurry to prepare a positive electrode slurry, 20 μm thick aluminum foil in the positive electrode slurry After coating to a thickness of 200 μm, the porosity was rolled to 30%, and dried at 60 ° C. for 24 hours to prepare a positive electrode.

Li ₄ Ti ₅ O ₁₂ (D50: 8.66 μm, BET: 4.01 m ² / g): Super-P: PVdF is weighed to be 93.5: 2: 4.5 and mixed in NMP to mix the negative electrode slurry. After preparing, the negative electrode slurry was coated on a copper foil having a thickness of 10 μm, rolled to have a porosity of 30%, and dried at 60 ° C. for 24 hours to prepare a negative electrode.

EC: DMC: DEC = 1: 2: A battery cell was prepared using an electrolyte solution containing 1M LiPF ₆ in a solvent.

&Lt; Comparative Example 1 &

A battery cell was manufactured in the same manner as in Example 1, except that the amount of Super-P: PVdF at the negative electrode was 3: 5.5.

Comparative Example 2

A battery cell was manufactured in the same manner as in Example 1 except that the amount of Super-P: PVdF at the negative electrode was 3: 6.5.

<Experimental Example 1>

The high temperature characteristics of Example 1 and Comparative Examples 1 and 2 were compared.

The SOC 100 was stored at a high temperature of 60 ° C., and 1C capacity and discharge resistance were measured every week.

Referring to Table 1, Comparative Examples 2 and 3 was similar to the initial resistance and resistance increase and decrease after 3 weeks high temperature storage, it was confirmed that the binder ratio is not significantly affected. Comparative Example 2 showed a similar level of capacity retention after high-temperature storage for 3 weeks, compared to Example 1, but it was confirmed that the resistance increase rate was relatively higher. In the case of Example 1 using a smaller amount of binder than Comparative Examples 1 and 2, it was confirmed that not only the initial resistance was low but also the resistance increase / decrease rate was relatively low at high temperature storage.

Before high temperature storage After 3 weeks of high temperature storage Volume
Retention rate (%) resistance
% Increase 1C capacity (mAh) Discharge resistance (mΩ) The third week
1C capacity (mAh) The third week
Discharge resistance (mΩ) Example 1 18.42 1.73 16.03 2.24 87.03 129.50 Comparative Example 1 18.26 1.93 16.09 2.63 88.12 136.22 Comparative Example 2 21.44 1.95 18.01 2.69 84.05 138.02

        Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (18)

Electrode collector;
An electrode mixture layer formed on the electrode current collector and including a lithium metal oxide and a binder;
The binder is a secondary battery electrode comprising a polyolefin-based binder. The electrode of claim 1, wherein the electrode mixture layer further comprises a conductive material within a range of more than 0.5 wt% to less than 3 wt% based on the total weight of the electrode mix. The electrode of claim 1, wherein the electrode mixture layer further comprises a conductive material within a range of 1% by weight to less than 3% by weight based on the total weight of the electrode mixture. The electrode of claim 1, wherein the electrode mixture layer further comprises a conductive material within a range of 2% by weight to less than 3% by weight based on the total weight of the electrode mixture. The electrode of claim 1, wherein a content of the polyolefin-based binder is in a range of more than 2.0 wt% to less than 5.5 wt% based on the total weight of the electrode mixture. The electrode according to claim 1, wherein the polyolefin-based binder is a halogen-substituted or unsubstituted poly olefin compound. The method of claim 1, wherein the polyolefin-based binder is polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), polyvinyl An electrode which is one or two or more compounds selected from the group consisting of chloride (PVC). The electrode represented by the formula (1) according to claim 1, wherein the lithium metal oxide is:
Li _a M ' _b O _4-c A _c (1)
In the above formula, M 'is at least one element selected from the group consisting of Ti, Sn, Cu, Pb, Sb, Zn, Fe, In, Al and Zr;
a and b are 0.1? a? 4; Is determined according to the oxidation number of M 'in the range of 0.2? B? 4;
c is determined according to the oxidation number in the range of 0? c <0.2;
A is one or more of an anion of -1 or -2. The electrode of claim 8, wherein the oxide of formula (1) is represented by the following formula (2):
Li _a Ti _b O ₄ (2)
In the above formula, 0.5? A? 3, 1? B? 2.5. The electrode of claim 9, wherein the lithium metal oxide is Li _1.33 Ti _1.67 O ₄ or LiTi ₂ O ₄ . The electrode of claim 1, wherein the lithium metal oxide is represented by the following general formula (3):
Li _x M _y Mn _2-y O _4-z A _z (3)
Wherein 0 < y < 2, 0 z < 0.2,
M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, ;
A is one or more of an anion of -1 or -2. The electrode according to claim 11, wherein the oxide of formula (3) is represented by the following formula (4):
Li _x Ni _y Mn _2-y O ₄ (4)
In the above formula, 0.9? X? 1.2 and 0.4? Y? 0.5. The electrode of claim 12, wherein the lithium metal oxide is LiNi _0.5 Mn _1.5 O ₄ or LiNi _0.4 Mn _1.6 O ₄ . A lithium secondary battery comprising an electrode and a polymer membrane according to any one of claims 1 to 13, wherein an electrode assembly having a structure in which a polymer membrane is interposed between a cathode and an anode is embedded in a battery case. The lithium secondary battery of claim 14, wherein the lithium secondary battery is a lithium ion battery. The lithium secondary battery of claim 14, wherein the lithium secondary battery is a lithium ion polymer battery. The lithium secondary battery of claim 14, wherein the lithium secondary battery is a lithium polymer battery. The method of claim 14, wherein after storage for 3 weeks at 60 ° C. with SOC 100, the measured capacity retention is in the range of at least 85% and less than 100%, and at the same time the resistance increase is at least 100% and less than 135% of the initial capacity. Lithium secondary battery in range.

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