Positive electrode manufacturing method and lithium secondary battery

Abstract

Provided is a positive electrode manufacturing method comprising the steps of: forming a lithium supplemental layer including a first positive electrode active material and a lithium supplemental material on a positive electrode current collector; and forming an active material layer including a second positive electrode active material on the lithium supplemental layer, wherein the step of forming the lithium supplemental layer includes a step of spraying a lithium supplemental slurry directly onto the positive electrode current collector.

Description

Method for manufacturing a positive electrode and lithium secondary battery

[0001] The present invention relates to a method for manufacturing a positive electrode and a lithium secondary battery, and more specifically, to a method for manufacturing a positive electrode and a lithium secondary battery capable of securing strong adhesion between a positive electrode current collector and an active material layer and increasing charge / discharge capacity.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0153492 dated November 1, 2024, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.

[0003] Rechargeable batteries are a representative example of electrochemical devices that utilize electrochemical energy, and their application areas are increasingly expanding. Recently, with the technological development and growing demand for portable devices such as portable computers, mobile phones, and cameras, the demand for rechargeable batteries as an energy source has been rapidly increasing. Among these rechargeable batteries, much research has been conducted on lithium-ion batteries, which have high energy density—that is, high capacity—and have been commercialized and are widely used.

[0004] Various studies are underway to improve the charge / discharge characteristics and durability of secondary batteries, and there is still room for improvement.

[0005] The first technical problem that the present invention aims to solve is to provide a method for manufacturing an anode capable of securing strong adhesion between the anode current collector and the active material layer.

[0006] The second technical objective of the present invention is to provide a lithium secondary battery capable of securing strong adhesion between the positive current collector and the active material layer, and having increased charge / discharge capacity.

[0007] To achieve the first technical objective, the present invention provides a method for manufacturing an anode, comprising the steps of: forming a lithium supplement layer comprising a first anode active material and a lithium supplement on an anode current collector; and forming an active material layer comprising a second anode active material on the lithium supplement layer, wherein the step of forming the lithium supplement layer comprises spraying the lithium supplement slurry directly onto the anode current collector.

[0008] In some embodiments, the lithium supplement slurry may have a viscosity of about 5,000 cPa to about 10,000 cPa at 25°C during the spraying step.

[0009] In some embodiments, the first positive active material and the second positive active material may include the same type of active material.

[0010] In some embodiments, the lithium supplement layer may further include a binder and a conductive material.

[0011] In some embodiments, the lithium supplement slurry may contain about 1.5 weight% to about 4.5 weight% of lithium supplement in the solid content.

[0012] In some embodiments, the thickness of the lithium supplement layer may be about 0.05 to about 0.4 times the thickness of the active material layer.

[0013] In some embodiments, the lithium supplement may comprise Li2O, Li2O2, LiF, Li2S, Li3N, Li5FeO4, Li6CoO4, Li2NiO2, Li2MnO3, Li2MoO3, Li2DHBN (3,4-dihydroxybenzonitrile dilithium salt), Li2C2O4, or a mixture thereof. In some embodiments, the lithium supplement may be Li5FeO4.

[0014] In some embodiments, the step of forming the active material layer may include the step of forming a first active material layer on the lithium supplement layer and the step of forming a second active material layer on the first active material layer.

[0015] In some embodiments, the spraying step may be performed by uniformly spraying the lithium replenishment slurry onto the positive current collector.

[0016] In some embodiments, the spraying step may be performed by spraying the lithium replenishment slurry onto the positive current collector in the form of a localized pattern.

[0017] To achieve the second technical objective, the present invention provides a lithium secondary battery comprising: a positive electrode; a negative electrode including a negative active material on a negative current collector; a separator provided between the positive electrode and the negative electrode; and an electrolyte, wherein the positive electrode includes a lithium supplementary layer including a first positive active material between the positive current collector and the active material layer, and the lithium supplementary layer includes LiFeO2. Here, the positive electrode is a positive electrode manufactured by the positive electrode manufacturing method described above.

[0018] In some embodiments, the lithium supplement layer may further include a compound of the following chemical formula 1.

[0019] <Chemical Formula 1>

[0020] Li a Fe 1-x M x O y

[0021] (Here, 1 <a≤5, 0≤x≤0.35, 2<y≤4, M은 Ga, Zr, Ti, Mg, Ca, Ba, Sc, Mn, Zn, Cu, V, Cr, Sr, In, Al, 또는 그 조합임)

[0022] In some embodiments, the lithium supplement layer may further include Li5FeO4.

[0023] By employing the anode manufacturing method of the present invention, strong adhesion between the anode current collector and the active material layer can be secured, and the charge / discharge capacity of the lithium secondary battery can also be increased.

[0024] The effects obtainable from the exemplary embodiments of the present invention are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects resulting from the implementation of the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0025] FIG. 1 is a schematic diagram showing an anode manufacturing apparatus according to one embodiment of the present invention.

[0026] FIG. 2 is a flowchart illustrating a method for manufacturing an anode according to one embodiment of the present invention.

[0027] FIG. 3 is a schematic diagram showing a cross-section of an anode manufactured according to one embodiment of the present invention.

[0028] FIG. 4 is a schematic diagram showing a cross-section of an anode according to another embodiment of the present invention.

[0029] FIG. 5 is a front view showing a lithium secondary battery according to one embodiment of the present invention.

[0030] FIG. 6 is a cross-sectional view showing an electrode assembly according to one embodiment of the present invention.

[0031] FIG. 7 is a cross-sectional view showing a cathode according to one embodiment of the present invention.

[0032] Hereinafter, preferred embodiments of the concept of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the concept of the present invention may be modified in various different forms, and the scope of the concept of the present invention should not be interpreted as being limited by the embodiments described below. It is preferable to interpret the embodiments of the concept of the present invention as being provided to more completely explain the concept of the present invention to those with average knowledge in the art. Identical reference numerals denote identical elements throughout. Furthermore, various elements and areas in the drawings are depicted schematically. Accordingly, the concept of the present invention is not limited by the relative sizes or spacing depicted in the accompanying drawings.

[0033] Terms such as first, second, etc. may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the concept of the present invention, the first component may be named the second component, and conversely, the second component may be named the first component.

[0034] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the concept of the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, expressions such as "comprising" or "having" are intended to indicate the existence of the features, number, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, actions, components, parts, or combinations thereof.

[0035] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the art to which the concept of the present invention pertains. Furthermore, it will be understood that commonly used terms, such as those defined in advance, should be interpreted as having meanings consistent with their intent in the context of the relevant technology, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0036] Where an embodiment can be implemented differently, a specific process sequence may be performed differently from the order described. For example, two processes described in succession may be performed substantially simultaneously or in the reverse order of the description.

[0037] In the accompanying drawings, variations of the depicted shapes may be anticipated, for example, depending on manufacturing techniques and / or tolerances. Accordingly, embodiments of the present invention should not be interpreted as being limited to specific shapes of the areas depicted herein, but should include, for example, variations in shape resulting from the manufacturing process. All terms "and / or" used herein include each of the mentioned components and all combinations of one or more of them.

[0038]

[0039] (1st embodiment)

[0040] FIG. 1 is a schematic diagram showing an anode manufacturing apparatus (100) according to one embodiment of the present invention. FIG. 2 is a flowchart showing an anode manufacturing method according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing a cross-section of an anode (10) manufactured according to one embodiment of the present invention.

[0041] Referring to FIGS. 1 to 3, the anode manufacturing device (100) may include an unwinder (151) configured to unwind an anode current collector (11), a spray nozzle (110) configured to spray a lithium supplement layer (13) onto the anode current collector (11), a coater (120) configured to form an active material layer (15) on the lithium supplement layer (13), and a rewinder (155) configured to rewound an anode (10) including the lithium supplement layer (13) and the active material layer (15).

[0042] In some embodiments, the positive current collector (11) may be wound in the unwinder (151), and the unwinder (151) may be configured to unwind the positive current collector (11) at a constant linear speed.

[0043] The above positive current collector (11) is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. The above positive current collector (11) may include, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel with a surface treated with carbon, nickel, titanium, silver, etc.

[0044] In some embodiments, the positive current collector (11) may form fine irregularities on its surface to increase adhesion with the active material or other particles described later. In some embodiments, the positive current collector (11) may have various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0045] In some embodiments, the positive current collector (11) may have a thickness of about 10 μm to about 25 μm, but the present invention is not limited thereto.

[0046] The lithium supplement layer (13) may be provided on the positive current collector (11). The lithium supplement layer (13) may be provided on the positive current collector (11) by spraying a lithium supplement slurry (111) through a spray nozzle (110) (S110).

[0047] The lithium supplement layer (13) may include a first positive electrode active material and a lithium supplement. In some embodiments, the lithium supplement layer (13) may further include a binder and a conductive material.

[0048] The first positive electrode active material may comprise, for example, a lithium transition metal oxide; a lithium metal iron phosphate; a lithium nickel-manganese-cobalt oxide; an oxide in which a portion of the lithium nickel-manganese-cobalt oxide is substituted with another transition metal; or two or more of these, but is not limited thereto. Specifically, the positive electrode active material may comprise, for example, a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; and a compound with the chemical formula Li 1+x Mn 2-x Lithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2, etc.; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, Cu2V2O7, etc.; chemical formula LiNi 1-x Ni-site type lithium nickel oxide represented by MxO2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); chemical formula LiMn 2-x M x Lithium manganese composite oxide represented by O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu, or Zn); Li in which part of the Li of the chemical formula is substituted with aluminum ions. 1+x(Ni a Co b Mn c Al d ) 1-x Examples include O2 (x = 0 to 0.03, a = 0.3 to 0.95, b = 0.01 to 0.35, c = 0.01 to 0.5, d = 0.001 to 0.03, a+b+c+d=1); lithium metal phosphate LiMPO4 (where M is M = Fe, Co, Ni, or Mn), disulfide compounds; Fe2(MoO4)3, etc., but are not limited to these.

[0049] The lithium supplement may comprise, for example, Li2O, Li2O2, LiF, Li2S, Li3N, Li5FeO4, Li6CoO4, Li2NiO2, Li2MnO3, Li2MoO3, Li2DHBN (3,4-dihydroxybenzonitrile dilithium salt), Li2C2O4, or a mixture thereof. In some embodiments, the lithium supplement may comprise Li5FeO4. In some embodiments, the lithium supplement may comprise Li2NiO2.

[0050] The above binder is adhesive, stable in electrochemical reactions, and capable of binding electrode materials such as the positive active material and positive conductive material to maintain a stable form, and is not limited to specific components.Non-limiting examples of such binders include styrene butadiene rubber (SBR), butadiene rubber (BR), nitrile butadiene rubber (NBR), styrene butadiene styrene block polymer (SBS), styrene ethylene butadiene block polymer (SEB), styrene-(styrene butadiene)-styrene block polymer, natural rubber (NR), isoprene rubber (IR), ethylene-propylene-diene terpolymer (EPDM), poly(ethylene-co-propylene-co-5-methylene-2-norbornene) polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyvinyl chloride, polyvinylidene fluoride-co-hexafluoropropylene, and polyvinylidene It may be polyvinylidene fluoride-co-trichloroethylene, polymethyl(meth)acrylate, polyethylhexylacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene, polypropylene, ethylene vinyl acetate copolymer (polyethylene-co-vinyl acetate), polyethylene oxide, polypropylene oxide, polyarylate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, or may contain two or more of these.Specifically, the binder may include styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), polymethyl methacrylate, polyethylhexyl acrylate, and polybutyl acrylate. In a specific embodiment, the binder may include one or more selected from these.

[0051] The above conductive material is intended to reduce electrical resistance and is not particularly limited as long as it is conductive without causing chemical changes in the battery. Non-limiting examples of the above conductive material include graphite such as natural graphite or artificial graphite; carbon black-based carbon compounds such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskey such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives. In a specific embodiment, the above conductive material may include one or more selected from these.

[0052] The above lithium supplement slurry may further include a solvent capable of dissolving or dispersing the first positive active material, the lithium supplement, the binder, and the conductive material.

[0053] In some embodiments, the solvent may be a solvent commonly used in the art, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water, and one of these alone or a mixture of two or more may be used.

[0054] The amount of the solvent used may be determined to dissolve or disperse the first positive active material, conductive material, and binder, taking into account the coating thickness and manufacturing yield of the lithium replenishment slurry. Furthermore, the amount of the solvent used may be determined so that the lithium replenishment slurry has a viscosity suitable for spraying.

[0055] In some embodiments, the lithium supplement slurry may have a viscosity of about 5000 cPa to about 10000 cPa at 25°C. In some embodiments, the lithium supplement slurry may have a range of about 5000 cPa to about 10000 cPa, about 5200 cPa to about 9800 cPa, about 5500 cPa to about 9500 cPa, about 5700 cPa to about 9300 cPa, about 6000 cPa to about 9000 cPa, about 6200 cPa to about 8800 cPa, about 6500 cPa to about 8500 cPa, about 6700 cPa to about 8300 cPa, about 7000 cPa to about 8000 cPa, about 7200 cPa to about 7800 cPa, or between any two of these values ​​at 25°C.

[0056] If the viscosity of the above lithium replenishment slurry is too low, excessive energy and time may be required for drying. If the viscosity of the above lithium replenishment slurry is too high, spray characteristics may be degraded.

[0057] In some embodiments, the lithium supplement slurry may contain about 1.5 weight% to about 4.5 weight% of lithium supplement in the solid content. In some embodiments, the lithium supplement slurry comprises a lithium supplement of about 1.5 wt% to about 4.5 wt%, about 1.6 wt% to about 4.4 wt%, about 1.7 wt% to about 4.3 wt%, about 1.8 wt% to about 4.2 wt%, about 1.9 wt% to about 4.1 wt%, about 2 wt% to about 4 wt%, about 2.1 wt% to about 3.9 wt%, about 2.2 wt% to about 3.8 wt%, about 2.3 wt% to about 3.7 wt%, about 2.4 wt% to about 3.6 wt%, about 2.5 wt% to about 3.5 wt%, about 2.6 wt% to about 3.4 wt%, about 2.7 wt% to about 3.3 wt%, about 2.8 wt% to about 3.2 wt%, and about 2.9 wt% in the solid content. It may have a range of up to about 3.1 weight%, or between any two of these figures.

[0058] The above lithium supplement plays a role in supplying lithium during the formation process, thereby contributing to reducing lithium loss in the cathode active material and maintaining charge / discharge capacity. If the content of the lithium supplement is excessively low, the effect of reducing lithium loss in the cathode active material is insufficient, which may lead to a decrease in the charge / discharge capacity of the manufactured battery. If the content of the lithium supplement is excessively high, electrical conductivity decreases, which may be economically disadvantageous.

[0059] In some embodiments, the lithium replenishment slurry may contain about 0.8 wt% to about 2.2 wt% of a conductive material in the solid content. In some embodiments, the lithium replenishment slurry may have a range of about 0.8 wt% to about 2.2 wt%, about 0.9 wt% to about 2.1 wt%, about 1 wt% to about 2 wt%, about 1.1 wt% to about 1.9 wt%, about 1.2 wt% to about 1.8 wt%, about 1.3 wt% to about 1.7 wt%, about 1.4 wt% to about 1.6 wt%, or between any two of these figures.

[0060] If the content of the conductive material is too small, the electrical resistance may increase excessively. If the content of the conductive material is too large, the fraction of the active material decreases, which may reduce the charge / discharge capacity.

[0061] In some embodiments, the lithium supplement slurry may contain about 1.5 weight% to about 4 weight% of a binder in the solid content. In some embodiments, the lithium supplement slurry may have a binder in the solid content of about 1.5 wt% to about 4 wt%, about 1.6 wt% to about 3.9 wt%, about 1.7 wt% to about 3.8 wt%, about 1.8 wt% to about 3.7 wt%, about 1.9 wt% to about 3.6 wt%, about 2 wt% to about 3.5 wt%, about 2.1 wt% to about 3.4 wt%, about 2.2 wt% to about 3.3 wt%, about 2.3 wt% to about 3.2 wt%, about 2.4 wt% to about 3.1 wt%, about 2.5 wt% to about 3 wt%, about 2.6 wt% to about 2.9 wt%, about 2.7 wt% to about 2.8 wt%, or a range between any two of these figures.

[0062] If the content of the above binder is too low, other components may easily detach, and the adhesion of the lithium supplement layer to the positive current collector may be insufficient. If the content of the above binder is too high, the electrical resistance increases excessively and the fraction of the active material decreases, which may reduce the charge / discharge capacity.

[0063] In some embodiments, the lithium supplement slurry may contain about 90% to about 95% by weight of the first positive electrode active material in the solid content.

[0064] If the content of the first positive electrode active material is too small, the charge / discharge capacity of the manufactured battery may be insufficient. If the content of the first positive electrode active material is too large, the mechanical properties of the manufactured battery may be degraded.

[0065] As previously explained, the lithium supplement layer (13) can be formed by spraying the lithium supplement slurry directly onto the positive current collector (11).

[0066] In some embodiments, the lithium replenishment slurry may be uniformly sprayed onto the positive current collector (11). In this case, the lithium replenishment layer (13) may be formed with a substantially uniform thickness over the entire surface area of ​​the retaining portion of the positive current collector (11).

[0067] In some other embodiments, the lithium replenishment slurry may be sprayed onto the positive current collector (11) in a localized pattern. In this case, the lithium replenishment layer (13) may be formed on a portion of the retaining portion of the positive current collector (11). Since the lithium replenishment layer (13) is formed in a pattern on the retaining portion of the positive current collector (11), a portion of the retaining portion of the positive current collector (11) may be exposed from the lithium replenishment layer (13). In some embodiments, the portion of the retaining portion exposed from the lithium replenishment layer (13) may be in direct contact with the active material layer (15) described later.

[0068] An active material layer (15) can be formed on the lithium supplement layer (13) using a coater (120) (S120).

[0069] The above active material layer (15) may include a second positive active material. Specifically, the above active material layer (15) may include a second positive active material, a positive conductive material, and a positive binder.

[0070] The positive conductive material and positive binder of the active material layer (15) are the same as those described above in relation to the conductive material and binder of the lithium supplement layer (13), so a detailed description is omitted here. In some embodiments, the positive conductive material of the active material layer (15) may be a material of the same type as the conductive material of the lithium supplement layer (13). In other embodiments, the positive conductive material of the active material layer (15) may be a material of a different type from the conductive material of the lithium supplement layer (13). In some embodiments, the positive binder of the active material layer (15) may be a material of the same type as the binder of the lithium supplement layer (13). In other embodiments, the positive binder of the active material layer (15) may be a material of a different type from the binder of the lithium supplement layer (13).

[0071] The second positive electrode active material may comprise, for example, a lithium transition metal oxide; a lithium metal iron phosphate; a lithium nickel-manganese-cobalt oxide; an oxide in which a portion of the lithium nickel-manganese-cobalt oxide is substituted with another transition metal; or two or more of these, but is not limited thereto. Specifically, the positive electrode active material may comprise, for example, a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; and a compound with the chemical formula Li 1+x Mn 2-xLithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2, etc.; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, Cu2V2O7, etc.; chemical formula LiNi 1-x Ni-site type lithium nickel oxide represented by MxO2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); chemical formula LiMn 2-x M x Lithium manganese composite oxide represented by O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu, or Zn); Li in which part of the Li of the chemical formula is substituted with aluminum ions. 1+x (Ni a Co b Mn c Al d ) 1-x Examples include O2 (x = 0 to 0.03, a = 0.3 to 0.95, b = 0.01 to 0.35, c = 0.01 to 0.5, d = 0.001 to 0.03, a+b+c+d=1); lithium metal phosphate LiMPO4 (where M is M = Fe, Co, Ni, or Mn), disulfide compounds; Fe2(MoO4)3, etc., but are not limited to these.

[0072] In some embodiments, the first positive active material and the second positive active material may be of the same type. In some embodiments, both the first positive active material and the second positive active material may comprise a lithium metal phosphate material.

[0073] In some embodiments, the first positive electrode active material and the second positive electrode active material may be different materials. In some embodiments, one of the first positive electrode active material and the second positive electrode active material may include a lithium metal phosphate material and the other may include a lithium nickel-manganese-cobalt oxide material.

[0074] In some embodiments, the active material layer (15) may contain about 0.8% by weight to about 2.2% by weight of a conductive material in the solid content. In some embodiments, the active material layer (15) may have a range of about 0.8% by weight to about 2.2% by weight, about 0.9% by weight to about 2.1% by weight, about 1% by weight to about 2% by weight, about 1.1% by weight to about 1.9% by weight, about 1.2% by weight to about 1.8% by weight, about 1.3% by weight to about 1.7% by weight, about 1.4% by weight to about 1.6% by weight, or between any two of these values.

[0075] If the content of the conductive material is too small, the electrical resistance may increase excessively. If the content of the conductive material is too large, the fraction of the active material decreases, which may reduce the charge / discharge capacity.

[0076] In some embodiments, the active material layer (15) may contain about 1.5 weight% to about 4 weight% of a binder in the solid content. In some embodiments, the active material layer (15) may have a binder in a solid content of about 1.5 wt% to about 4 wt%, about 1.6 wt% to about 3.9 wt%, about 1.7 wt% to about 3.8 wt%, about 1.8 wt% to about 3.7 wt%, about 1.9 wt% to about 3.6 wt%, about 2 wt% to about 3.5 wt%, about 2.1 wt% to about 3.4 wt%, about 2.2 wt% to about 3.3 wt%, about 2.3 wt% to about 3.2 wt%, about 2.4 wt% to about 3.1 wt%, about 2.5 wt% to about 3 wt%, about 2.6 wt% to about 2.9 wt%, about 2.7 wt% to about 2.8 wt%, or a range between any two of these figures.

[0077] If the content of the binder is too small, other components may easily detach, and the adhesion between the active material layer (15) and the lithium supplement layer (13) may be insufficient. If the content of the binder is too large, the electrical resistance may increase excessively and the fraction of the active material may decrease, thereby reducing the charge / discharge capacity.

[0078] In some embodiments, the active material layer (15) may contain about 90% to about 95% by weight of the second positive active material in the solid content.

[0079] If the content of the second positive electrode active material is too small, the charge / discharge capacity of the manufactured battery may be insufficient. If the content of the second positive electrode active material is too large, the mechanical properties of the manufactured battery may be degraded.

[0080] In some embodiments, the relative composition ratio of the second positive active material, positive binder, and positive conductive material of the active material layer (15) may be substantially the same as the relative composition ratio of the first positive active material, binder, and conductive material of the lithium supplementary layer (13).

[0081] In some embodiments, the total thickness of the active material layer (15) may be about 80 μm to about 300 μm. In some embodiments, the total thickness of the active material layer (15) may be about 80 μm to about 300 μm, about 90 μm to about 290 μm, about 100 μm to about 280 μm, about 110 μm to about 270 μm, about 120 μm to about 260 μm, about 130 μm to about 250 μm, about 140 μm to about 240 μm, about 150 μm to about 230 μm, about 160 μm to about 220 μm, about 170 μm to about 210 μm, about 180 μm to about 200 μm, or a range between any two of these values. However, the present invention is not limited thereto. The method of measuring thickness is not limited thereto, but may be a value measured using, for example, a thickness gauge (Mitutoyo, VL-50S-B).

[0082] The thickness (T1) of the lithium supplement layer (13) may be thinner than the thickness (T2) of the active material layer (15). In some embodiments, the thickness (T1) of the lithium supplement layer (13) may be about 0.05 to about 0.4 times the thickness (T2) of the active material layer (15).

[0083] If the thickness (T1) of the lithium replenishment layer (13) is relatively too thick compared to the thickness (T2) of the active material layer (15), the charge / discharge capacity of the manufactured battery may be insufficient. Conversely, if the thickness (T1) of the lithium replenishment layer (13) is relatively too thin compared to the thickness (T2) of the active material layer (15), the effect of reducing loss of the positive active material and maintaining charge / discharge capacity may be insufficient. Here, saying that the thickness (T1) of the lithium replenishment layer (13) is relatively too thin or too thick compared to the thickness (T2) of the active material layer (15) means that when comparing the thickness (T1) of the lithium replenishment layer (13) with the thickness (T2) of the active material layer (15), it is thinner or thicker than it is outside the appropriate range. Therefore, saying that the thickness (T1) of the lithium supplement layer (13) is relatively too thin or too thick compared to the thickness (T2) of the active material layer (15) is not a comparison of the absolute values ​​of the thickness (T1) of the lithium supplement layer (13) and the thickness (T2) of the active material layer (15).

[0084] In FIG. 3, a lithium replenishment layer (13) and an active material layer (15) are shown provided on one surface of the positive current collector (11), but the lithium replenishment layer (13) and the active material layer (15) may be formed on both surfaces. In this case, after forming the lithium replenishment layer (13) and the active material layer (15) on one surface of the positive current collector (11), the lithium replenishment layer (13) and the active material layer (15) may be additionally formed on the other surface of the positive current collector (11).

[0085] The anode (10) on which the active material layer (15) is formed by the above-mentioned coater (120) can be transferred to a drying oven (130).

[0086] The drying oven (130) may include a heating device inside. In some embodiments, the drying oven (130) may be configured to supply heated gas inside. In some embodiments, the temperature inside the drying oven (130) may be maintained at about 120°C to about 180°C. However, the present invention is not limited thereto.

[0087] As the anode (10) passes through the drying oven (130), the solvent can be removed.

[0088] The dried anode (10) can be rolled by a rolling roller (140). As the anode (10) is rolled, the components of the anode (10) become closely attached and the density of each layer increases.

[0089] The anode (10) that has been rolled can then be wound onto a rewinder (155).

[0090] In the manufacture of the above-mentioned positive electrode (10), a lithium supplement layer (13) containing a lithium supplement with a larger particle size than the active material is formed by a spray method, so it can be bonded with the positive electrode current collector (11) with strong adhesive force. Therefore, the lithium supplement layer (13) can mediate a strong bond between the positive electrode current collector (11) and the active material layer (15).

[0091] In addition, by providing a lithium supplement layer (13) between the positive current collector (11) and the active material layer (15) to supply additional lithium ions, the irreversible capacity can be reduced, and thus the charge / discharge capacity can be increased.

[0092]

[0093] (2nd Example)

[0094] FIG. 4 is a schematic diagram showing a cross-section of an anode (10a) according to another embodiment of the present invention. The anode (10a) according to this embodiment differs from the anode (10) described with reference to FIG. 3 in that the active material layer (15) includes two layers (15a, 15b), and all other aspects are the same. Therefore, the following description focuses on these differences, and specific descriptions of common aspects are omitted.

[0095] Referring to FIG. 4, the active material layer (15) may include a lower active material layer (15a) and an upper active material layer (15b). The lower active material layer (15a) may be disposed on the lithium supplement layer (13). In some embodiments, the upper active material layer (15b) may be disposed on the lower active material layer (15a).

[0096] The lower active material layer (15a) comprises a lower positive active material, and the upper active material layer (15b) may comprise an upper positive active material. The lower positive active material and the upper positive active material may each independently comprise a positive active material as described below.

[0097] The above-mentioned positive electrode active material may comprise, for example, lithium transition metal oxide; lithium metal iron phosphate; lithium nickel-manganese-cobalt oxide; an oxide in which a portion of lithium nickel-manganese-cobalt oxide is substituted with another transition metal; or two or more of these, but is not limited thereto. Specifically, the above-mentioned positive electrode active material may comprise, for example, a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; and a compound with the chemical formula Li 1+x Mn 2-x Lithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2, etc.; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, Cu2V2O7, etc.; chemical formula LiNi1-x Ni-site type lithium nickel oxide represented by MxO2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); chemical formula LiMn 2-x M x Lithium manganese composite oxide represented by O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu, or Zn); Li in which part of the Li of the chemical formula is substituted with aluminum ions. 1+x (Ni a Co b Mn c Al d ) 1-x Examples include O2 (x = 0 to 0.03, a = 0.3 to 0.95, b = 0.01 to 0.35, c = 0.01 to 0.5, d = 0.001 to 0.03, a+b+c+d=1); lithium metal phosphate LiMPO4 (where M is M = Fe, Co, Ni, or Mn), disulfide compounds; Fe2(MoO4)3, etc., but are not limited to these.

[0098] In some embodiments, an interface may exist between the lower active material layer (15a) and the upper active material layer (15b).

[0099] The lower active material layer (15a) and the upper active material layer (15b) may each further include an anode conductive material and an anode binder. Since the anode conductive material and the anode binder of the lower active material layer (15a) and the upper active material layer (15b) are the same as those described in relation to the conductive material and binder of the lithium supplementary layer (13) described above, a detailed description is omitted here.

[0100]

[0101] (3rd Example)

[0102] FIG. 5 is a front view showing a lithium secondary battery (1) according to one embodiment of the present invention.

[0103] Referring to FIG. 5, a lithium secondary battery (1) according to one embodiment of the present invention comprises a positive electrode, a negative electrode, and a battery case (250) in which the electrode assembly is mounted. In some embodiments, the lithium secondary battery (1) may further comprise an electrolyte together with an electrode assembly (not shown) inside the battery case (250). In some embodiments, the lithium secondary battery (1) may further comprise a solid electrolyte between the positive electrode and the negative electrode.

[0104] For example, the above electrolyte or solid electrolyte allows ions to move between the positive and negative electrodes, and through this ion exchange between the positive and negative electrodes, the lithium secondary battery (1) can perform charging and discharging. Examples of the electrolyte or solid electrolyte used in the present invention include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc., which can be used when manufacturing a lithium secondary battery, but are not limited to these.

[0105] Additionally, the battery case (250) includes a sealing portion (255) of a structure sealed by heat fusion along the outer circumference. The battery case (250) may be a laminate sheet comprising a resin layer and a metal layer. In some embodiments, the battery case (250) is made of a laminate sheet and may consist of an outer resin layer forming the outermost layer, a barrier metal layer preventing the penetration of material, and an inner resin layer for sealing. However, the embodiments of the present invention are not limited to the structure described above and may be replaced with a battery case of a secondary battery of a different general structure.

[0106] Additionally, the electrode assembly (not shown) may be formed in a jelly-roll type (wound type), stack type (laminated type), or composite type (stack and folding type) structure. In some embodiments, the electrode assembly (not shown) may include an anode, a cathode, and a separator disposed between them.

[0107] Additionally, in this embodiment, the battery case (250) may be structured such that an electrode lead (240), which is electrically connected to a plurality of electrode tabs (not shown) extending from an electrode assembly (not shown), is exposed to the outside. More specifically, the electrode lead (240) may protrude outwardly from the battery case (250) through the sealing portion (255). Additionally, in this embodiment, a lead film (260) may be positioned between the electrode lead (240) and the sealing portion (255).

[0108] The lead film (260) can not only prevent a short circuit from occurring between the electrode lead (240) and the blocking metal layer of the battery case (250), but also improve the sealing performance of the battery case (250). When the lead film (260) is provided, the phenomenon of reduced adhesion during thermal fusion between the metal electrode lead (240) and the polymer battery case (250) can be prevented. Additionally, it is preferable that the lead film (260) be an insulating material capable of blocking the application of current from the electrode lead (240) to the battery case (250). The lead film (260) is made of a film having insulating and thermal fusion properties. The lead film (260) may include one or more layers of material selected from, for example, polyimide (PI), polypropylene, polyethylene, and polyethylene terephthalate (PET). In some embodiments, the length of the lead film (260) may be increased to also serve the function of preventing a short circuit in the portion of the electrode lead (240) exposed outside the battery case (250).

[0109] In some embodiments, the electrode lead (240) includes an anode lead (241) electrically connected to an anode tab included in the electrode assembly and a cathode lead (245) electrically connected to a cathode tab included in the electrode assembly.

[0110] In some embodiments, the lithium secondary battery (1) may be a bidirectional pouch battery cell in which a positive lead (241) and a negative lead (245) protrude from each side of the battery case (250). However, not limited thereto, the lithium secondary battery (1) may be a unidirectional pouch battery cell in which a positive lead (241) and a negative lead (245) are arranged together on the same side of the battery case (250). In other embodiments, the lithium secondary battery (1) may be a secondary battery in which an electrode assembly is housed within a prismatic or cylindrical battery case.

[0111] Although the following description is based on bidirectional pouch battery cells, it may be described in the same or similar manner for unidirectional pouch battery cells. A person skilled in the art will understand that the following description is applicable to unidirectional pouch battery cells, prismatic secondary batteries, and cylindrical battery cases.

[0112] FIG. 6 is a cross-sectional view showing an electrode assembly (40) according to one embodiment of the present invention.

[0113] Referring to FIG. 6, the electrode assembly (40) is formed by alternately stacking a positive electrode (10) and a negative electrode (20) with a separator (30) in between. At this time, the electrode assembly (40) may be provided with electrode tabs, and the electrode tabs are connected to the positive electrode (10) and the negative electrode (20) of the electrode assembly (40), respectively, and may protrude outward from the electrode assembly (40). A plurality of electrode tabs connected to the positive electrode (10) and a plurality of electrode tabs connected to the negative electrode (20) may protrude from the electrode assembly (40) in different directions and / or the same direction. The manufactured electrode assembly (40) may be housed in a battery case (150). As previously described, the lithium secondary battery (1) including the electrode assembly (40) may be manufactured in a pouch type, a prismatic type, or a cylindrical type.

[0114]

[0115] As previously described, the anode (10) includes an anode active material layer (15) on a lithium supplement layer (13).

[0116] The lithium supplement layer (13) may contain LiFeO2. In some embodiments, the lithium supplement layer (13) may contain LiFeO2 in an amount of about 1 wt% to about 2.5 wt%. In some embodiments, the lithium supplement layer (13) may contain LiFeO2 in an amount of about 1 wt% to about 2.5 wt%, about 1.1 wt% to about 2.4 wt%, about 1.2 wt% to about 2.3 wt%, about 1.3 wt% to about 2.2 wt%, about 1.4 wt% to about 2.1 wt%, about 1.5 wt% to about 2 wt%, about 1.6 wt% to about 1.9 wt%, about 1.7 wt% to about 1.8 wt%, or a range between any two of these values.

[0117] In some embodiments, the LiFeO2 in the lithium supplement layer (13) may be converted from the Li5FeO4 in the lithium supplement slurry provided to the lithium supplement layer (13) when manufacturing the anode (10) through a formation process.

[0118] In some embodiments, the lithium supplement layer (13) may include a compound of the following formula 1.

[0119] <Chemical Formula 1>

[0120] Li a Fe 1-x M x O y

[0121] (Here, 1 <a≤5, 0≤x≤0.35, 2<y≤4, M은 Ga, Zr, Ti, Mg, Ca, Ba, Sc, Mn, Zn, Cu, V, Cr, Sr, In, Al, 또는 그 조합임)

[0122] In some embodiments, the lithium supplement layer (13) is Li3FeO 3.5 It may include. In some embodiments, the lithium supplement layer (13) may include a small amount of Li5FeO4.

[0123] The above positive active material layer (15) has been described above with reference to FIGS. 3 and FIGS. 4, so a detailed description is omitted here.

[0124] FIG. 7 is a cross-sectional view showing a cathode (20) according to one embodiment of the present invention.

[0125] Referring to FIG. 7, the cathode (20) is formed by coating cathode active material layers (22, 23) on both sides of a cathode current collector (21).

[0126] In FIG. 7, the negative active material layer provided on one surface of the negative current collector (21) is shown as being provided in two layers, but it may be provided in one layer. Also, in FIG. 7, the negative active material layer is shown as being provided on both surfaces of the negative current collector (21), but the negative active material layer may be provided on only one surface.

[0127] The above negative current collector (21) is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. The above negative current collector (21) may be, for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, a copper or stainless steel surface treated with carbon, nickel, titanium, silver, etc., or an aluminum-cadmium alloy.

[0128] In some embodiments, the negative current collector (21) may form fine irregularities on its surface to increase the bonding strength with the negative active material described later. In some embodiments, the negative current collector (21) may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0129] In some embodiments, the negative current collector (21) may have a thickness of about 1 μm to about 100 μm, but the present invention is not limited thereto.

[0130] In some embodiments, the negative active material layer (22, 23) may include a first negative active material layer (22) and a second negative active material layer (23).

[0131] The first cathode active material layer (22) and the second cathode active material layer (23) may each independently include a cathode active material as described below.

[0132] The above-mentioned cathode active material is carbon, for example, graphite-based carbon such as non-graphitized carbon, natural graphite, or artificial graphite; Li xFe2O3(0≤x≤1), Li x WO2(0≤x≤1), Sn x Me 1-x Me y O z (wherein Me is one or more of Mn, Fe, Pb, and Ge, and Me' is one or more of Al, B, P, Si, elements of Group 1, Group 2, and Group 3 of the periodic table, and halogens, and 0 <x≤1, 1≤y≤3, 1≤z≤8) 등의 금속 복합 산화물; 리튬 금속; 리튬 합금; 규소계 합금; 주석계 합금; SiO, SiO / C, SiO2등의 실리콘계 산화물; SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, 및 Bi2O5등의 금속 산화물; 폴리아세틸렌 등의 도전성 고분자; Li-Co-Ni 계 재료 등을 사용할 수 있으나, 이들만으로 한정되는 것은 아니다.

[0133] In some embodiments, the negative electrode active material may be a Si-based negative electrode active material and may include one or more of, for example, Li2SiO3, Li2Si2O5, Li3SiO3, and Li4SiO4.

[0134] In some embodiments, the negative electrode active material may include a Si-based negative electrode active material containing carbon. Specifically, the negative electrode active material may further include a carbon coating layer on the particle surface. In this case, the amount of the carbon coating may be 20% by weight or less, preferably about 1% to about 20% by weight, based on the total weight of the silicon-based negative electrode active material.

[0135] Referring again to FIG. 6, the electrode assembly (40) may include a separator (30) between the positive electrode (10) and the negative electrode (20).

[0136] In some embodiments, the separator (30) separates the positive electrode (10) and the negative electrode (20) and provides a passage for the movement of lithium ions, and can be used without special limitations as long as it is a separator typically used in lithium-ion secondary batteries. In particular, it is desirable that the separator (30) has low resistance to the movement of ions of the electrolyte and excellent electrolyte retention capacity.

[0137] Specifically, a porous polymer film, such as a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof, may be used as the separator (30). Alternatively, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers, may be used as the separator (30). Additionally, a coated separator containing a ceramic component or a polymer material may be used to ensure heat resistance or mechanical strength, and the separator (30) may have a single-layer or multi-layer structure. In some embodiments, the separator (30) may include a safety reinforced separator (SRS) with a thin coating of a ceramic material on its surface.

[0138] In addition, conventional porous nonwoven fabrics, such as high-melting-point glass fibers, polyethylene terephthalate fibers, etc., may be used as the separation membrane (30), but are not limited thereto.

[0139] However, if the lithium secondary battery (1) described with reference to Fig. 5 is a solid-state secondary battery, the separator (30) may be omitted.

[0140] Referring again to FIG. 5, the lithium secondary battery (1) may further include an electrolyte.

[0141] The above electrolyte may be one or more mixed organic solvents selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), gamma butyrolactone (GBL), fluoroethylene carbonate (FEC), methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, pentyl acetate, methyl propionate, ethyl propionate, ethyl propionate, and butyl propionate.

[0142] In some embodiments, the electrolyte may further comprise a lithium salt, and the anion of the lithium salt is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , F3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N -It may be one or more selected from a group consisting of

[0143] In some embodiments, the electrolyte may comprise a lithium salt, an organic solvent, and a coumarin-based additive. The electrolyte comprising the coumarin-based additive can effectively remove oxygen gas generated from the sacrificial cathode material.

[0144] In some embodiments, the coumarin-based additive may include a compound having the structure of Formula 2 or Formula 3 below.

[0145] <Chemical Formula 2>

[0146]

[0147] (Here, R1 to R5 are each independently selected from the group consisting of H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, and R is an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, or -OR'(R' is an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms))

[0148] <Chemical Formula 3>

[0149]

[0150] (Here, R1 is an alkyl group having 1 to 10 carbon atoms, R2 is an alkylene group having 1 to 10 carbon atoms, L is a direct bond, -O-, -COO-, -RO-, or -R'COO-, R and R' are each independently an alkylene group having 1 to 10 carbon atoms, and m is an integer from 0 to 5)

[0151] In some embodiments, the coumarin-based additive may be contained in the electrolyte in an amount of about 0.01 weight% to about 5 weight% based on the total weight of the electrolyte. In some embodiments,

[0152] The above coumarin-based additive may be included in the electrolyte in an amount of about 0.01 wt% to about 5 wt%, about 0.02 wt% to about 4.5 wt%, about 0.05 wt% to about 4 wt%, about 0.07 wt% to about 3.7 wt%, about 0.1 wt% to about 3.5 wt%, about 0.15 wt% to about 3.3 wt%, about 0.2 wt% to about 3 wt%, about 0.3 wt% to about 2.7 wt%, about 0.4 wt% to about 2.5 wt%, about 0.5 wt% to about 2.2 wt%, about 0.6 wt% to about 2 wt%, about 0.7 wt% to about 1.8 wt%, about 0.8 wt% to about 1.5 wt%, or a range between any two of these figures, based on the total weight of the electrolyte.

[0153] If the content of the above coumarin-based additive is too low, the effect of removing O2 may be insufficient. If the content of the above coumarin-based additive is too high, battery performance may be degraded due to increased resistance.

[0154]

[0155] As described above, although embodiments of the present invention have been described in detail, a person skilled in the art to which the present invention pertains will be able to modify and implement the present invention in various ways without departing from the spirit and scope of the present invention as defined in the appended claims. Therefore, future modifications to the embodiments of the present invention will not depart from the technology of the present invention.

[0156]

[0157] [Explanation of the symbol]

[0158] 1: Lithium secondary battery

[0159] 10: Anode

[0160] 11: Positive current collector

[0161] 13: Lithium replenishment layer

[0162] 15: Active material layer

[0163] 15a: Lower active material layer

[0164] 15b: Upper active material layer

[0165] 20: Cathode

[0166] 21: Cathode current collector

[0167] 22: First cathode active material layer

[0168] 23: Second negative electrode active material layer

[0169] 30: Separator

[0170] 40: Electrode assembly

[0171] 100: Anode manufacturing device

[0172] 110: Spray nozzle

[0173] 111: Lithium replenishment slurry

[0174] 120: Cotter

[0175] 130: Drying oven

[0176] 151: Unwinder

[0177] 155: Rewinder

[0178] 240: Electrode Lead

[0179] 241: Positive lead

[0180] 245: Cathode Lead

[0181] 250: Battery Case

[0182] 255: Sealing part

[0183] 260: Lead film

Claims

1. A step of forming a lithium supplement layer comprising a first positive active material and a lithium supplement on a positive current collector; and A step of forming an active material layer containing a second positive active material on the lithium supplement layer; Includes, A method for manufacturing an anode, comprising the step of forming the lithium supplement layer by spraying the lithium supplement slurry directly onto the anode current collector.

2. In Paragraph 1, A method for manufacturing an anode, characterized in that, in the above spraying step, the lithium replenishment slurry has a viscosity of about 5000 cPa to about 10000 cPa at 25°C.

3. In Paragraph 1, A method for manufacturing an anode characterized in that the first anode active material and the second anode active material comprise the same type of active material.

4. In Paragraph 1, A method for manufacturing an anode characterized in that the lithium supplementary layer further comprises a binder and a conductive material.

5. In Paragraph 4, A method for manufacturing an anode characterized by the above lithium replenishment slurry containing about 1.5 weight% to about 4.5 weight% of a lithium replenishing agent among the solids.

6. In Paragraph 1, A method for manufacturing an anode characterized in that the thickness of the lithium supplement layer is about 0.05 to about 0.4 times the thickness of the active material layer.

7. In Paragraph 1, A method for manufacturing an anode characterized by the above lithium supplement comprising Li2O, Li2O2, LiF, Li2S, Li3N, Li5FeO4, Li6CoO4, Li2NiO2, Li2MnO3, Li2MoO3, Li2DHBN (3,4-dihydroxybenzonitrile dilithium salt), Li2C2O4, or a mixture thereof.

8. In Paragraph 7, A method for manufacturing an anode characterized in that the above lithium supplement is Li5FeO4.

9. In Paragraph 1, A method for manufacturing an anode characterized by the step of forming the active material layer comprising the step of forming a first active material layer on the lithium supplement layer and the step of forming a second active material layer on the first active material layer.

10. In Paragraph 1, A method for manufacturing an anode, characterized in that the above-mentioned spraying step is performed by uniformly spraying the lithium supplement slurry onto the anode current collector.

11. In Paragraph 1, A method for manufacturing an anode, characterized in that the above-mentioned spraying step is performed by spraying the lithium supplement slurry onto the anode current collector in the form of a localized pattern.

12. An anode manufactured by an anode manufacturing method according to any one of claims 1 to 11; A cathode comprising a cathode active material on a cathode current collector; A separator provided between the anode and the cathode; and Electrolytes; Includes, A lithium secondary battery in which the above positive electrode comprises a lithium supplementary layer containing the first positive electrode active material between the positive electrode current collector and the active material layer, and the lithium supplementary layer contains LiFeO2.

13. In Paragraph 12, A lithium secondary battery characterized in that the lithium supplementary layer further comprises a compound of the following chemical formula 1. <Chemical Formula 1> Li a Feb 1-x M x O y (Here, 1 <a≤5, 0≤x≤0.35, 2<y≤4, M은 Ga, Zr, Ti, Mg, Ca, Ba, Sc, Mn, Zn, Cu, V, Cr, Sr, In, Al, 또는 그 조합임) 14. In Paragraph 12, A lithium secondary battery characterized in that the above lithium supplementary layer further comprises Li5FeO4.

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