KR20220122271A - Current collector and thin film battery having the same - Google Patents

Abstract

The present invention provides a current collector and a thin film battery including the same, wherein the current collector has a structure in which a conductive oxide layer is laminated on an aluminum layer, the thickness of the aluminum layer is 70 nm or more, and the thickness of the conductive oxide layer is 30 to 180 nm.

Description

Current collector and thin film battery including same

The present invention relates to a current collector and a thin film battery including the same.

As miniaturization and weight reduction of electronic equipment are realized and the use of portable electronic equipment is generalized, studies on secondary batteries having high energy density as their power sources are being actively conducted.

Examples of the secondary battery include a nickel-cadmium battery, a nickel-metal hydride battery, a nickel-metal hydride battery, a nickel-hydrogen battery, and a lithium secondary battery. In addition, research on lithium secondary batteries having high energy density per unit weight and capable of rapid charging is on the rise.

In general, lithium secondary batteries are manufactured by using a material capable of inserting and deintercalating lithium ions as a positive electrode and a negative electrode, charging a non-aqueous electrolyte between the positive electrode and negative electrode, and oxidizing when lithium ions are inserted and desorbed from the positive electrode and negative electrode. It generates electrical energy by reaction and reduction reaction.

On the other hand, since the liquid electrolyte is used, there is a risk of safety issues due to overheating and the like becoming a topic of discussion. In order to overcome the problems of lithium secondary batteries using liquid electrolytes, research and development of all-solid-state lithium secondary batteries using solid electrolytes are being actively conducted in recent years.

Among them, the major research fields currently being developed are the cathode active material field and the solid electrolyte field. In the case of a lithium secondary battery that is currently commercialized, an aluminum foil or the like is used as a current collector. However, when the conventional aluminum foil is used as a current collector, spontaneous oxidation and corrosion reactions occur in the electrolyte solution, and thus the battery cannot function as a current collector, thereby reducing the performance of the battery.

In order to solve this problem, Korean Patent Laid-Open Publication No. 10-2013-0106965 and the like disclose a current collector including platinum (Pt), etc., which has excellent high-temperature stability and oxidation stability during battery charging and discharging. However, in the case of platinum (Pt), there is a problem in that the price of the battery is too high, which increases the overall price of the battery, and thus there is a limitation in that production and economic efficiency are low.

Republic of Korea Patent Publication No. 10-2013-0106965 (published on October 1, 2013)

The present invention provides a current collector that can replace the conventionally expensive platinum (Pt) and aluminum, which has a limitation in that the performance of the battery is deteriorated due to spontaneous oxidation and corrosion reactions occurring in the electrolyte solution and thus failing to serve as a current collector and An object of the present invention is to provide a thin film battery including the same.

The present invention provides a current collector comprising a structure in which a conductive oxide layer is laminated on an aluminum layer, wherein the aluminum layer has a thickness of 70 nm or more, and the conductive oxide layer has a thickness of 30 to 180 nm do.

In addition, the present invention provides a thin film battery including the current collector.

The current collector and the thin film battery including the same according to the present invention secure the flexibility and lightness of the battery due to the conductive oxide layer laminated on the aluminum layer, and provide the same conductivity as the platinum (Pt) to prevent deterioration of battery performance This can be done, and the production cost can be lowered, thereby increasing production and economic efficiency.

1 is a schematic diagram showing a stacked structure of a thin film battery according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

In the present invention, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

Spatially relative terms such as “bottom”, “bottom”, “bottom”, “top”, “top”, “upper”, etc. It can be used to easily describe the correlation with the components. Spatially relative terms should be understood as terms including different orientations of the device during use or operation in addition to the orientation shown in the drawings. For example, when an element shown in the drawing is turned over, an element described as "below" or "below" another element may be placed "above" or "above" the other element. Accordingly, the exemplary term “down” may include both the downward and upward directions. The device may also be oriented in other orientations, and thus spatially relative terms may be interpreted according to orientation.

<The current collector>

The current collector of the present invention serves as an intermediate medium for supplying electrons provided from an external conductor to the electrode active material, or, conversely, collects electrons generated as a result of an electrode reaction and flows to the external conductor. , including any layer, laminated structure, or film recognized by those skilled in the art as typically performing this function in a secondary battery.

In addition, the current collector is an important constituent material in realizing the shape of the actual electrode plate, and in particular, the positive electrode is important that the current collector metal is not oxidized in a high potential region, and the current collector has electronic conductivity, electrochemical stability, and electrode plate In consideration of the manufacturing process, etc., aluminum (Al) or platinum (Pt) is usually used for the positive electrode, and active material particles are coated thereon and dried to manufacture the positive electrode plate.

However, in the case of a current collector including only aluminum, the flexibility is not excellent due to the metal of the aluminum, and it is difficult to achieve lightness of the battery. In addition, in the case of platinum (Pt), there is a problem in that the price of the battery is too high, which increases the overall price of the battery, and thus there is a limitation in that production and economic efficiency are low.

Accordingly, the current collector according to the present invention can solve the above problem by including a structure in which a conductive oxide layer is laminated on an aluminum (Al) layer. Specifically, the aluminum layer of the current collector of the present invention has a function as an electron transfer path due to low electrical resistance, and since the conductive oxide layer is stable in electrochemical oxidation reaction, it is possible to prevent oxidation of the lower aluminum side.

The aluminum layer of the present invention may be in the form of a foil or a mesh having holes in a non-limiting shape. An aluminum alloy in which an arbitrary material is added to aluminum may be used.

The conductive oxide layer is not particularly limited as long as it has conductivity and includes an oxide, but may include indium oxide, fluorine-doped indium oxide, and the like, and preferably include indium oxide.

The indium oxide may include an oxide mixed with at least one selected from the group consisting of zinc (Zn), potassium (Ga) and tin (Sn) and indium (In), specifically, indium oxide (Indium Oxide) , may include at least one selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (ITZO), and indium zinc oxide gallium (IGZO).

The current collector according to the present invention can prevent deterioration of battery performance by giving the same conductivity as platinum (Pt), etc. while securing flexibility and lightness of the battery due to the conductive oxide layer laminated on the aluminum layer, and the production cost can be lowered, thereby increasing production and economic efficiency.

In the case of including an oxide such as Ti, Si, Al, Cu, etc. instead of indium oxide, it is not preferable because the contact resistance with the electrode layer increases and a problem that the output density of the electrode decreases may occur.

In addition, when the conductive oxide layer is used alone as the current collector, a problem in which battery energy cannot be output due to high resistance may occur, which is not preferable.

In addition, when the conductive oxide layer is laminated on the aluminum layer and the conductive oxide layer is laminated in the direction of the active material of the secondary battery, the aluminum layer is laminated on the conductive oxide layer, not in the direction of the active material of the secondary battery. , when charging the electrode layer, the aluminum layer is oxidized, which is not preferable.

For the above reasons, it is preferable that the conductive oxide layer be laminated in the direction of the active material of the secondary battery. FIG. 1 is a schematic diagram showing the stacked structure of a thin film battery according to an embodiment of the present invention, and the conductive oxide layer of the present invention This is an example in which the positive active material of this secondary battery is stacked "?

The thickness of the aluminum layer included in the current collector according to the present invention may be 70 nm or more, preferably 70 nm to 1 μm, more preferably 70 to 300 nm, and most preferably 100 nm to 300 nm. When the thickness of the aluminum layer is less than 70 nm, energy loss may occur due to an increase in resistance.

In addition, the thickness of the conductive oxide layer included in the current collector according to the present invention may be 30 nm to 180 nm, preferably 50 nm to 150 nm. If the thickness of the conductive oxide layer is less than 30 nm, the current collector may be damaged due to failure to prevent oxidation of the aluminum layer.

The sheet resistance value of the current collector including the stacked structure according to the present invention may be 3 Ω/sqare or less, preferably 0.1 to 2 Ω/sqare. When the low sheet resistance value of the above range is satisfied, there is an advantage in that the efficiency of the thin film battery including the current collector can be increased, and it is advantageous for electron movement by reducing the contact resistance with the cathode material and prevents heat generation due to the high contact resistance. can

The current collector according to the present invention may be laminated by coating a conductive oxide layer on an aluminum layer. The coating may be performed by a thermal fusion method, a plating method, a vapor deposition method, etc., but is not limited thereto.

As the coating method, for example, an electroplating method using electric energy, a chemical plating method using a chemical change, a penetration plating method for forming a film by diffusion penetration, and spraying a molten metal onto the object to be plated with a sprayer to form a film plating methods such as a metal fusion method, a chemical vapor deposition method in which a volatile metal is evaporated to form a film on a body to be plated by thermal decomposition, etc., a cathode sputtering method, a vacuum deposition plating method, an ion plating method, etc., but are not limited thereto.

In addition, as the vapor deposition method, there are a PVD method, which is physical deposition, and a CVD method, which is a chemical deposition, as the vapor deposition method, and the PVD method includes a vacuum deposition method using resistance heating, electron beam heating, and induction heating; sputtering method; ion plating method; molecular beam epitaxy; There are an ion deposition method and the like, and the CVD method includes a thermal CVD method such as an atmospheric pressure CVD method and a reduced pressure CVD method; photoCVD methods such as photolysis and thermal decomposition; Coulomb discharge methods such as inductively coupled type Coulomb discharge and capacitively coupled type Coulomb discharge; Plasma CVD methods, such as ECR discharge, etc. exist.

The current collector according to the present invention may further include a metal layer or an oxide thin film layer for improving adhesion between the substrate and the current collector or the current collector and the active material.

The metal layer or oxide thin film layer for improving adhesion may include Ti, LiF, Ni, ITO, etc., and the ITO layer included in the adhesion improving layer is independent of the conductive oxide layer included in the current collector of the present invention. .

<Thin film battery>

The present invention may provide a thin film battery including the current collector described above.

The thin film battery including the current collector according to the present invention may include a positive electrode, a negative electrode, and an electrolyte interposed between the positive electrode and the negative electrode. As the positive electrode, the negative electrode, and the electrolyte interposed between the positive electrode and the negative electrode, well-known ones can be applied without limitation within the range that does not impair the object and effect of the present invention.

Although the stacked structure of the thin film battery according to an embodiment of the present invention is shown in FIG. 1 , the scope of the present invention is not limited thereto.

Specifically, if the structure in which the conductive oxide layer is laminated on the aluminum layer according to the present invention is satisfied, the stacking order of the positive electrode and the negative electrode is not limited.

In addition, the positive electrode and the negative electrode may be prepared by a conventional method known in the art. For example, a slurry is prepared by mixing and stirring a solvent, a binder, a conductive material, and a dispersant, if necessary, with the positive electrode active material or negative electrode active material, and then applying (coating) it to one surface of the current collector according to the present invention, compressing it, and drying it. An anode or a cathode can be manufactured.

The positive electrode may include a current collector and a positive active material layer formed on the current collector, and the negative electrode may include a negative current collector and a negative electrode active material layer formed on the negative current collector.

It is preferable that the positive active material has a structure laminated on the conductive oxide layer of the current collector to prevent oxidation of the current collector.

As the positive active material, as long as it can reversibly insert and release lithium ions, it may be used without particular limitation. Specifically, as the positive active material, one or more of a complex oxide or a complex phosphate of a metal of cobalt, manganese, nickel, aluminum, iron, or a combination thereof and lithium may be used, for example, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, or lithium iron phosphate can be used. As a representative example thereof, the lithium-containing compound described below may be used.

Li _x Mn _1-y M _y A ₂ (1)

Li _x Mn _1-y M _y O _2-z X _z (2)

Li _x Mn ₂ O _4-z X _z (3)

Li _x Mn _2-y M _y M' _z A ₄ (4)

Li _x Co _1-y M _y A ₂ (5)

Li _x Co _1-y M _y O _2-z X _z (6)

Li _x Ni _1-y M _y A ₂ (7)

Li _x Ni _1-y M _y O _2-z X _z (8)

Li _x Ni _1-y Co _y O _2-z X _z (9)

Li _x Ni _1-yz Co _y M _z A _α (10)

Li _x Ni _1-yz Co _y M _z O _2-α X _α (11)

Li _x Ni _1-yz Mn _y M _z A _α (12)

Li _x Ni _1-yz Mn _y M _z O _2-α X _α (13)

In the above formula, 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M' are the same or different from each other, and Mg, Al, Co, K, Na, Ca , Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and selected from the group consisting of rare earth elements, A is selected from the group consisting of O, F, S and P is selected from, and X is selected from the group consisting of F, S and P.

The negative electrode current collector may be used without particular limitation as long as it has conductivity without causing chemical change in the thin film battery. For example, as the negative electrode current collector, copper, aluminum, stainless steel, nickel, titanium, calcined carbon, a surface treatment of copper or stainless steel with carbon, nickel, titanium, silver, etc., an aluminum-cadmium alloy, etc. may be used. and preferably, a current collector including a structure in which an aluminum layer and a conductive oxide layer included in the current collector according to the present invention are stacked may be used.

As the anode active material, an anode active material capable of inserting and deintercalating lithium ions known in the art may be used without particular limitation, and as the anode active material, a carbon material such as crystalline carbon, amorphous carbon, carbon composite material, or carbon fiber , lithium metal, lithium alloy, etc. may be used. For example, the amorphous carbon includes hard carbon, coke, mesocarbon microbead (MCMB) calcined at 1500° C. or lower, mesophase pitch-based carbon fiber (MPCF), and the like. As crystalline carbon, there are graphite-based materials, and specifically, there are natural graphite, artificial graphite, graphitized coke, graphitized MCMB, graphitized MPCF, and the like.

The carbonaceous material has a d002 interplanar distance of 3.35 to 3.38 Å, and Lc (crystallite size) by X-ray diffraction is preferably a material having at least 20 nm or more. As the lithium alloy, an alloy of lithium and aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, or indium may be used.

The positive active material and the negative active material may be mixed with a binder and a solvent, respectively, to prepare a positive electrode active material slurry or an electrode active material slurry of the negative electrode active material slurry.

The binder is a material that acts as a paste of the active material, mutual adhesion of the active material, adhesion to the current collector, and a buffer effect against expansion and contraction of the active material, for example, polyvinylidene fluoride, polyhexafluoropropylene -Polyvinylidenefluoride copolymer, polyvinyl acetate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, polyvinyl ether, polymethyl methacrylate, polyethyl acrylate, polytetra fluoroethylene, polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, styrene-butadiene rubber, and acrylonitrile-butadiene rubber. The content of the binder is 0.1 to 30 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the total electrode active material. If the content of the binder is too small, the adhesive force between the electrode active material and the current collector is insufficient, and if the content of the binder is too large, the adhesion is improved, but the content of the electrode active material is reduced by that amount, which may be disadvantageous in increasing the battery capacity.

As a solvent of the active material slurry, a non-aqueous solvent or an aqueous solvent may be generally used. As the non-aqueous solvent, for example, acetone, N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, N,N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran, etc. may be used. and water, isopropyl alcohol, etc. may be used as the aqueous solvent, but is not limited thereto.

If necessary, the electrode active material slurry may further include a conductive material, a thickener, and the like.

The conductive material is a material that improves electron conductivity, and may be used without limitation as long as it does not cause chemical change and has electronic conductivity. Specifically, at least one selected from the group consisting of a graphite-based conductive material, a carbon black-based conductive material, and a metal or metal compound-based conductive material may be used. Examples of the graphite-based conductive material include artificial graphite, natural graphite, and the like, and examples of the carbon black-based conductive material include acetylene black, ketjen black, denka black, thermal black, and channel black ( channel black), carbon fiber, etc., and examples of the metal-based or metal compound-based conductive material include copper, nickel, aluminum, silver, tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , LaSrMnO ₃ and a perovskite material, and a conductive polymer such as a polyphenylene derivative may be used, but is not limited to the conductive materials listed above.

The content of the conductive material is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the total electrode active material. If the content of the conductive material is less than 0.1 parts by weight, electrochemical properties may be deteriorated, and if it exceeds 10 parts by weight, energy density per weight may decrease.

The thickener is not particularly limited as long as it can control the viscosity of the active material slurry, but for example, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, etc. may be used.

The positive and negative electrode active material slurries prepared as described above may be applied to positive and negative current collectors to prepare positive and negative electrodes.

The electrolyte interposed between the positive electrode and the negative electrode may be used without limitation as long as it is an electrolyte for a thin film battery, as long as it is a commonly used electrolyte or electrolyte, and preferably, an inorganic solid electrolyte or an organic solid electrolyte may be used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

Examples of the inorganic solid electrolyte include Li ₂ OB ₂ O ₃ , Li ₂ OV ₂ O ₅ -SiO ₂ , Li ₂ SO ₄ -Li ₂ OB ₂ O ₃ , Li ₃ PO ₄ , Li ₂ OLi ₂ WO ₄ -B ₂ O ₃ , LiPON (Li _2.9 PO _3.3 N _0.46 ), LiBON (Li _3.099 BO _2.532 N _0.516 ), and the like, and these may be used alone or in combination of two or more.

Examples of the organic solid electrolyte include lithium derivatives such as polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphoric acid ester polymers, poly agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, etc. A mixture of salts may be used, and these may be used alone or in combination of two or more.

Examples of the lithium salt include LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN(SO ₂ F) ₂ , LiN(SO ₂ CF ₃ ) ₂ , Li(CF) ₃ SO ₂ ) ₂ N, LiN(SO ₃ C ₂ F ₅ ) ₂ , LiB(C ₂ O ₄ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ , Li(CF ₃ SO ₃ ), LiC(SO ₂ ) CF ₃ ) ₃ , LiN(SO ₃ CF ₃ ) ₂ , LiC ₄ F ₉ SO ₃ , LiAlO ₄ , LiAlO ₂ , LiB(C ₂ O ₄ ) ₂ , LiAlCl ₄ , Li(CH ₃ CO ₂ ), Li(FSO) ₂ ) ₂ N, Li(CF ₃ SO ₂ ) ₃ C, LiCl, LiBr, or LiI, and the like, but are not limited thereto. These can be used individually or in mixture of 2 or more types.

The electrolyte may have a thickness of 0.7 to 3.0 μm.

In addition, a separate separator (separator) may exist between the positive electrode and the negative electrode according to the type of the thin film battery. As such a separation membrane, it can be used without particular limitation as long as it is commonly used in the art. In particular, it is suitable for the electrolyte to have low resistance to ion movement in the electrolyte and excellent moisture content of the electrolyte. It may be a conventional porous polymer film, or a porous nonwoven fabric, conventionally used as a separator, for example, an ethylene homopolymer, a propylene homopolymer, an ethylene/butene copolymer, an ethylene/hexene copolymer, an ethylene/methacrylate copolymer, It may be a material selected from polyester, Teflon, polytetrafluoroethylene, glass fiber having a high melting point, and polyethylene terephthalate, but is not limited thereto.

The separation membrane may have a pore diameter of 0.01 to 10 μm and a thickness of 3 to 100 μm, but is not limited thereto, and may be a single membrane or a multilayer membrane.

The thin film battery may be manufactured by a manufacturing method commonly known in the art. For example, the thin film battery is manufactured by obtaining a laminate by interposing a separator between the positive electrode and the negative electrode, then winding or folding the laminate to accommodate it in a thin film battery container, injecting an electrolyte into the thin film battery container, and sealing it with an encapsulating member can do.

The shape of the thin film battery of the present invention is not particularly limited, but may be a cylindrical shape, a square shape, a pouch type, or a coin type using a can.

Hereinafter, examples will be given to describe the present specification in detail. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present specification to those of ordinary skill in the art.

Example 1

A 0.5 T-thick glass (Corning) was used as a base substrate, and aluminum (Al) and indium tin oxide (ITO) were sequentially deposited to a thickness of 70 nm and 30 nm, respectively, as a positive electrode current collector on the glass substrate. Subsequently, LCO having a thickness of 3 μm as a positive active material, LiPON having a thickness of 2 μm as an electrolyte, and Li having a thickness of 2 μm as an anode active material were sequentially deposited. Then, the negative electrode current collector was deposited in the same composition and thickness as the positive electrode current collector to prepare the thin film battery of Example 1.

Examples 2 to 9 and Comparative Examples 1 to 9

A thin film battery was manufactured in the same configuration and method as in Example 1, except that the current collector configuration was changed as shown in Table 1 below.

composition current collector layer 1 layer 2 layer (conductive oxide layer) Al Conductive oxide layer (ITO) ITO Non-conductive oxide layer (TiO2) Al Example 1 70 nm - 30 nm - - Example 2 100 nm - 30 nm - - Example 3 100 nm - 50 nm - - Example 4 100 nm - 100 nm - - Example 5 100 nm - 150 nm - - Example 6 150 nm - 50 nm - - Example 7 150 nm - 100 nm - - Example 8 200 nm - 150 nm - - Example 9 300 nm - 180 nm - - Comparative Example 1 100 nm - - - - Comparative Example 2 - - 100 nm - - Comparative Example 3 50 nm - 25 nm - - Comparative Example 4 50 nm - 50 nm - - Comparative Example 5 50 nm - 100 nm - - Comparative Example 6 100 nm - 25 nm - - Comparative Example 7 100 nm - 200 nm - - Comparative Example 8 100 nm - - 100 nm - Comparative Example 9 - 100 nm - - 100 nm

Experimental Example 1: Damage to the current collector and whether the battery is driven

The thin film batteries of the Examples and Comparative Examples were charged at 0.1 C at room temperature until it reached 4.2 V, and discharged at 0.1 C until it reached 3.0 V to check whether the battery was driven. After the charge/discharge test, it was visually confirmed whether the current collector was damaged, and the results are shown in Table 2 below.

<Whether the current collector is damaged>

O: No damage to the current collector

X: Damage to the current collector

Experimental Example 2: Evaluation of sheet resistance

For the thin film batteries of Examples and Comparative Examples, the sheet resistance was measured with a sheet resistance measuring device (NAPSON RG-80). The measured sheet resistance was evaluated according to the following evaluation criteria, and the results are shown in Table 2 below.

<Criteria for evaluation of surface resistance>

○: 2 Ω/sq or less

△: more than 2 Ω/sq to 3 Ω/sq or less

X: >3 Ω/sq

Whether the current collector is damaged Battery powered or not Sheet resistance (Ω/sq) Example 1 O O △ Example 2 O O △ Example 3 O O O Example 4 O O O Example 5 O O O Example 6 O O O Example 7 O O O Example 8 O O O Example 9 O O O Comparative Example 1 X X △ Comparative Example 2 O X X Comparative Example 3 X X X Comparative Example 4 X X X Comparative Example 5 X X X Comparative Example 6 X X △ Comparative Example 7 O X X Comparative Example 8 X X X Comparative Example 9 O X O

As can be seen in Table 2, in the case of an embodiment including a current collector satisfying the stacking order and thickness range according to the present invention, the same conductivity as conventional platinum (Pt) while securing flexibility and lightness of the battery It can be confirmed that it is possible to prevent the deterioration of battery performance by giving it, and it is possible to lower the production cost, thereby increasing production and economic efficiency.

On the other hand, if it consists of a single layer of an aluminum layer or a conductive oxide layer, if it includes a non-conductive oxide layer such as TiO ₂ rather than a conductive oxide layer, and if the stacking order or thickness of each layer is out of the range, charge/discharge test results result in damage to the current collector Alternatively, it is possible to check a problem in which an abnormality occurs in battery operation, and the result of deterioration of battery performance due to poor conductivity can be confirmed.

Claims (7)

A current collector comprising a structure in which a conductive oxide layer is laminated on an aluminum layer,
The thickness of the aluminum layer is 70 nm or more,
The current collector, characterized in that the thickness of the conductive oxide layer is 30 to 180 nm.
According to claim 1,
The conductive oxide layer is a current collector, characterized in that it comprises indium oxide.
3. The method of claim 2,
The indium oxide is at least one selected from the group consisting of indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium tin oxide (ITZO), and indium zinc oxide gallium (IGZO) A current collector, characterized in that it comprises a.
According to claim 1,
A current collector, characterized in that the sheet resistance value of the current collector is 3 Ω/sqare or less.
According to claim 1,
The current collector, characterized in that the conductive oxide layer is laminated in the direction of the positive active material of the secondary battery.
A positive electrode comprising the current collector and the positive electrode active material according to any one of claims 1 to 5; and a thin film battery comprising an anode.
7. The method of claim 6,
The cathode active material is to be laminated on the conductive oxide layer of the current collector, a thin film battery.

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