Lithium secondary battery

Abstract

Presented is a lithium secondary battery comprising: a positive electrode including a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector; a negative electrode including a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector; and an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, wherein the negative electrode intercalates lithium upon charging, the negative electrode plates lithium upon charging, the negative electrode is a prelithiated negative electrode in which lithium ions are intercalated into the negative electrode active material layer, and a prelithiation compensation ratio calculated by equation 3 is 1.0 to 1.07: <Equation 3> Prelithiation compensation ratio = (capacity per unit area of negative electrode − prelithiation capacity per unit area of negative electrode) / capacity per unit area of positive electrode.

Description

lithium secondary battery

[0001] This is about lithium secondary batteries.

[0002]

[0003] Lithium batteries currently on the market mainly use carbon-based negative electrode active materials such as graphite. Carbon-based negative electrode active materials do not change in volume during charging and discharging, so the stability of lithium batteries is high. The theoretical electric capacity of graphite is small, about 372 mAh / g.

[0004] Meanwhile, lithium metal can be used as a negative electrode active material. The theoretical electric capacity of lithium metal is very large, approximately 3,860 mAh / g. During charging and discharging, dendrites can form on the surface of lithium metal due to side reactions with the electrolyte, and as these dendrites grow, they can cause a short circuit between the positive and negative electrodes. Consequently, the lifespan characteristics of a lithium metal battery containing lithium metal may be degraded.

[0005] Accordingly, there is a growing need for lithium metal batteries with high stability that minimize volume change.

[0006]

[0007] One aspect is to provide a lithium secondary battery containing a negative electrode of a new structure.

[0008]

[0009] A lithium secondary battery is provided, comprising, according to one embodiment, a positive electrode including a positive current collector and a positive active material layer on the positive current collector; a negative electrode including a negative current collector and a negative active material layer on the negative current collector; and an electrolyte layer disposed between the positive active material layer and the negative active material layer; wherein the negative electrode intercalates lithium by charging, the negative electrode plating lithium by charging, and the negative electrode is a prelithiated negative electrode in which lithium ions are intercalated in the negative active material layer, and the prelithiation compensation ratio calculated by the following Equation 3 is 1.0 to 1.07.

[0010] <Mathematical Formula 3>

[0011] Prelithiation compensation ratio = (Capacity per unit area of ​​the cathode - Prelithiation capacity per unit area of ​​the cathode) / Capacity per unit area of ​​the anode.

[0012]

[0013] According to one aspect, by employing a lithium secondary battery having a pre-lithiated lithium capacity-controlled negative electrode, it is possible to provide a lithium secondary battery with improved lifespan characteristics.

[0014]

[0015] FIG. 1 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0016] Figure 2 is a schematic cross-sectional view showing an enlarged view of A in Figure 1 before lithium is intercalated.

[0017] Figure 3 is a schematic cross-sectional view showing an enlarged view of A in Figure 1 after lithium has been intercalated.

[0018] Figure 4 is a schematic cross-sectional view showing an enlarged view of A in Figure 1 after lithium has been precipitated.

[0019]

[0020] The present inventive concept described below is subject to various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present inventive concept to specific embodiments and should be understood to include all modifications, equivalents, or substitutions that fall within the scope of the description of the present inventive concept.

[0021] The terms used below are used merely to describe specific embodiments and are not intended to limit the creative concept. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the following, terms such as “comprising” or “having” are intended to indicate the existence of the features, numbers, steps, actions, components, parts, components, materials, 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, steps, actions, components, parts, components, materials, or combinations thereof. The “ / ” used below may be interpreted as “and” or “or” depending on the context.

[0022] In the drawings, thicknesses have been enlarged or reduced to clearly represent various layers and regions. Throughout the specification, the same reference numerals have been used for similar parts. Throughout the specification, when a part such as a layer, film, region, or plate is described as being “on” or “above” another part, this includes not only cases where it is directly above another part but also cases where there is another part in between. Throughout the specification, terms such as “first,” “second,” etc., may be used to describe various components, but the components should not be limited by these terms. In this specification and drawings, components having substantially the same functional configuration are referred to by the same reference numerals to avoid redundant descriptions.

[0023] In the present disclosure, the “size” of a particle is, for example, the “particle diameter” of the particle. The “particle diameter” of the particle represents the average diameter when the particle is spherical and represents the average major axis length when the particle is non-spherical. The particle diameter of the particle can be measured using a particle size analyzer (PSA). The “particle diameter” of the particle is, for example, the “average particle diameter”. The average particle diameter is, for example, the median particle diameter (D50). The median particle diameter (D50) is the particle size corresponding to the 50% cumulative volume calculated from the side of the particle having a small particle size in the particle size distribution measured, for example by laser diffraction.

[0024] In the present disclosure, “metal” includes both metals and metalloids such as silicon and germanium in an elemental or ionic state.

[0025] In this disclosure, “alloy” means a mixture of two or more metals.

[0026] In the present disclosure, “anode active material” refers to an anode material capable of undergoing lithiation and delithiation.

[0027] In the present disclosure, “anode active material” refers to an anode material capable of undergoing lithiation and delithiation.

[0028] In the present disclosure, “lithiation” and “to lithiate” refer to the process of adding lithium to a positive electrode active material or a negative electrode active material.

[0029] In the present disclosure, “delithiation” and “to delithiate” refer to the process of removing lithium from a positive electrode active material or a negative electrode active material.

[0030] In this disclosure, “charge” and “to charge” refer to the process of providing electrochemical energy to a battery.

[0031] In this disclosure, “anode” and “cathode” refer to electrodes where electrochemical reduction and lithiation occur during the discharge process.

[0032] In this disclosure, “cathode” and “anode” refer to electrodes where electrochemical oxidation and delithiation occur during the discharge process.

[0033] In the present disclosure, “the areal capacity of the cathode” refers to the areal area of ​​the cathode (1 cm²). 2 It refers to the amount of electric charge that can be stored (mAh / cm²). 2 ).

[0034] In the present disclosure, “the areal intercalation capacity of the anode” refers to the unit area of ​​the anode (1 cm²). 2 It refers to the amount of charge that can be stored by the intercalation of lithium (mAh / cm²). 2 ).

[0035] In the present disclosure, “the areal plating capacity of the anode” refers to the unit area of ​​the anode (1 cm²). 2 It refers to the amount of charge that can be stored by the precipitation of lithium (mAh / cm²). 2 ).

[0036] In the present disclosure, “the areal capacity of the anode” refers to the unit area of ​​the anode (1 cm²). 2 It refers to the amount of electric charge that can be stored (mAh / cm²). 2 That is, the “areal capacity of the anode” can be expressed as the sum of the “areal intercalation capacity of the anode” and the “areal plating capacity of the anode.”

[0037] In the present disclosure, the N / P ratio may be defined as the ratio of the capacity per unit area of ​​the cathode to the capacity per unit area of ​​the anode (capacity per unit area of ​​the cathode / capacity per unit area of ​​the anode). That is, in this specification, the N / P ratio is calculated by dividing the sum of the intercalation capacity per unit area of ​​the cathode and the deposition capacity per unit area of ​​the cathode by the capacity per unit area of ​​the anode.

[0038] In the present disclosure, “the areal prelithiation capacity of the anode” refers to the unit area of ​​the anode (1 cm²). 2 It refers to the amount of charge that can be stored by pre-lithiated lithium (mAh / cm²). 2 ).

[0039] In the present disclosure, the “Prelithiation compensation Ratio (PCR)” means the value obtained by subtracting the “areal prelithiation capacity of the anode” from the “areal capacity of the anode” and dividing the result by the “areal capacity of the cathode.”

[0040] A lithium secondary battery and a method for manufacturing the same according to exemplary embodiments will be described in more detail below.

[0041] FIG. 1 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0042] Referring to FIG. 1, a lithium secondary battery (10) according to one embodiment of the present disclosure comprises: a positive electrode (100) comprising a positive current collector (110) and a positive active material layer (120) on the positive current collector (110); a negative electrode (200) comprising a negative current collector (210) and a negative active material layer (220) on the negative current collector (210); and an electrolyte layer (300) disposed between the positive active material layer (120) and the negative active material layer (220).

[0043] positive electrode (100)

[0044] The positive current collector (110) may provide a reference surface on which the positive active material layer (120) is disposed. The positive current collector (110) may include, for example, a plate or foil comprising indium (In), copper (Cu), magnesium (Mg), stainless steel (SUS), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. The thickness of the positive current collector (110) may be, for example, 5 μm to 100 μm, 5 μm to 50 μm, or 8 μm to 25 μm. In another embodiment, the positive current collector (110) may be omitted. Although not illustrated, a carbon layer with a thickness of 10 nm to 4 μm may be further disposed between the positive current collector (110) and the positive active material layer (120) to increase the bonding strength between the positive current collector and the positive active material layer (120). The carbon layer may include amorphous carbon, crystalline carbon, etc.

[0045] The positive active material layer (120) includes a positive active material and may further include a binder and / or a conductive material. The positive active material layer (120) may further include an additive that can serve as a sacrificial anode.

[0046] The content of the positive active material in the positive active material layer (120) may be 90% to 99.5% by weight with respect to 100% by weight of the positive active material layer (120). The content of the binder and the conductive material may each be 0.5% to 5% by weight with respect to 100% by weight of the positive active material layer (120).

[0047] The binder serves to adhere the positive active material particles well to each other and also to adhere the positive active material well to the positive current collector (110). Representative examples of binders include polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc., but are not limited thereto.

[0048] A conductive material is used to impart conductivity to an electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Examples of conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, silver, etc., in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0049] The cathode active material may use a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound). Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used. The composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0050] As an example, a compound represented by any one of the following chemical formulas may be used. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Lia FePO4(0.90≤a≤1.8).

[0051] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al, or a combination thereof.

[0052] The areal capacity of the cathode is a value that can be determined by the thickness, density, type and content of the cathode active material layer (120), etc. For example, the areal capacity of the cathode can be calculated by the following mathematical formula 1.

[0053] <Mathematical Formula 1>

[0054] C cat = C s × ρ × d

[0055] In the above mathematical formula 1, C cat is the capacitance per unit area of ​​the anode, and C s is the specific capacity of the positive active material, ρ is the density of the positive active material layer, and d is the thickness of the positive active material layer. The specific capacity of the positive active material, the density of the positive active material layer, and the thickness of the positive active material layer can be derived through the ordinary technical judgment of a person skilled in the art or through commonly used evaluation methods.

[0056] cathode (200)

[0057] A cathode (200) according to one embodiment of the present disclosure is configured to intercalate lithium by charging and to plating lithium by charging. Both the intercalated lithium and the plating lithium are cathodes (200) capable of realizing reversible capacities.

[0058] Referring to FIG. 1 and FIG. 2, FIG. 2 is an enlarged schematic diagram of region A of FIG. 1. Referring to FIG. 2, the negative electrode active material layer (220) includes a negative electrode active material (1) and includes a space in which lithium ions can be intercalated.

[0059] FIG. 3 is an enlarged schematic diagram of area A of FIG. 1. FIG. 3 shows that lithium ions (2) are intercalated into the negative active material (1) contained in the negative active material layer (220) by charging. Based on the above and subsequent descriptions, the 'intercalation capacity per unit area of ​​the negative electrode' of this specification refers to the capacity per unit area in which lithium ions (2) can be intercalated into the negative active material layer (220) as shown in FIG. 3.

[0060] FIG. 4 is an enlarged schematic diagram of area A of FIG. 1. FIG. 4 shows that lithium metal (3) is deposited (plated) on the surface of the negative active material (1), such as the pores and / or lithium-affinity metal, inside and / or between the negative active material (1) and / or between the negative active material (1), after lithium ions (2) are intercalated in the negative active material (1) by charging, or while lithium ions (2) are intercalated in the negative active material (1). Based on the foregoing and subsequent descriptions, the 'depositing capacity per unit area of ​​the negative electrode' in this specification refers to the capacity per unit area in which lithium metal (3) can be deposited in the negative active material layer (220) as shown in FIG. 4.

[0061] The negative current collector (210) may provide a reference surface on which the negative active material layer (220) is disposed. The negative current collector (210) may include, for example, a plate or foil comprising indium (In), copper (Cu), magnesium (Mg), stainless steel (SUS), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. The thickness of the negative current collector (210) may be, for example, 5 μm to 100 μm, 5 μm to 50 μm, or 8 μm to 25 μm.

[0062] The negative electrode active material layer (220) may include a negative electrode active material. The negative electrode active material layer (220) may further include a lithium-affinity metal. As another example, the negative electrode active material layer (220) may further include a binder and / or a conductive material.

[0063] The content of the negative electrode active material in the negative electrode active material layer (220) may be 90% to 99.5% by weight or 95% to 99% by weight with respect to 100% by weight of the negative electrode active material layer (220).

[0064] The content of the lithium-affinity metal in the negative electrode active material layer (220) may be 0.1 to 10 weight%, 0.5 to 5 weight%, or 1 to 3 weight% with respect to 100 weight% of the negative electrode active material layer (220).

[0065] The content of the binder may be 0.1 to 10 weight%, 0.5 to 5 weight%, or 1 to 3 weight% with respect to 100 weight% of the negative electrode active material layer (220).

[0066] The content of the conductive material may be 0.1 to 10 weight%, 0.5 to 5 weight%, or 1 to 3 weight% with respect to 100 weight% of the negative active material layer (220).

[0067] The binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the negative electrode current collector (210). As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used.

[0068] Examples of non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0069] The water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0070] When a water-based binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As the cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0071] The dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0072] A conductive material is used to impart conductivity to an electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjenblack, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials in the form of metal powder or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0073] The negative electrode active material in the negative electrode active material layer (220) includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0074] A material capable of reversibly intercalating / deintercalating lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc. As the lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn may be used.

[0075] Si-based or Sn-based negative electrode active materials may be used as materials capable of doping and undoping lithium. The above-mentioned Si-based negative electrode active materials include silicon, silicon-carbon composites, and SiO₂. x(0 < x < 2), Si-Q alloy (wherein Q is selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (excluding Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof), or a combination thereof. The Sn-based negative electrode active material may be Sn, SnO2, Sn-based alloy, or a combination thereof. The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The above secondary particles may exist dispersed in an amorphous carbon matrix. The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core. The Si-based negative electrode active material or the Sn-based negative electrode active material may be used in combination with a carbon-based negative electrode active material.

[0076] The areal intercalation capacity of the anode is a value that can be determined according to the thickness, density, type and content of the anode active material layer (220), etc. For example, the areal intercalation capacity of the anode can be calculated by the following mathematical formula 2.

[0077] <Mathematical Formula 2>

[0078] C an = C s × ρ × d

[0079] In the above mathematical formula 2, Can is the intercalation capacity per unit area of ​​the cathode, and C s is the specific capacity of the negative electrode active material, ρ is the density of the negative electrode active material layer, and d is the thickness of the negative electrode active material layer. The specific capacity of the negative electrode active material, the density of the negative electrode active material layer, and the thickness of the negative electrode active material layer can be derived through the ordinary technical judgment of a person skilled in the art or through commonly used evaluation methods.

[0080] The areal capacity of the cathode of a lithium secondary battery (10) according to one embodiment of the present disclosure may exceed the areal intercalation capacity of the anode per unit area. As the areal capacity of the cathode of a lithium secondary battery (10) according to one embodiment of the present disclosure exceeds the areal intercalation capacity of the anode per unit area, lithium metal may be reversibly plated / stripped in the pores within the anode active material layer (220).

[0081] According to one embodiment of the present disclosure, the ratio of the intercalation capacity per unit area of ​​the negative electrode and the capacity per unit area of ​​the positive electrode of a lithium secondary battery (10) may be, for example, 0.38 to 0.5, 0.4 to 0.5, or 0.42 to 0.47. By satisfying the above ranges for the ratio of the intercalation capacity per unit area of ​​the negative electrode and the capacity per unit area of ​​the positive electrode of the lithium secondary battery (10), plating of lithium metal can be induced within the negative electrode active material layer. By satisfying the above ranges for the ratio of the intercalation capacity per unit area of ​​the negative electrode and the capacity per unit area of ​​the positive electrode of the lithium secondary battery (10), the formation of lithium dendrites can be suppressed.

[0082] A lithium-affinity metal is a metal capable of inducing lithium ions that have migrated from the anode (100) to the negative electrode active material layer (220) to be deposited (plated) inside the negative electrode active material layer (220) in excess of the intercalation capacity per unit area of ​​the negative electrode. The lithium-affinity metal may include, for example, at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), or zinc (Zn), or any combination thereof. The lithium-affinity metal may be, for example, lithium-affinity metal particles. The average particle size of the lithium-affinity metal particles may be, for example, 10 nm to 4 μm, 10 nm to 1 μm, 10 nm to 500 nm, 10 nm to 100 nm, or 20 nm to 80 nm.

[0083] The areal plating capacity of the anode is a value that can be determined by the thickness, density, and type and content of the lithium-affinity metal of the anode active material layer (220). For example, if the content of the lithium-affinity metal of the anode active material layer (220) is increased, the plating capacity of the anode per unit area increases, and if the content of the lithium-affinity metal is decreased, the plating capacity of the anode per unit area decreases.

[0084] According to one embodiment of the present disclosure, the ratio of the intercalation capacity per unit area of ​​the cathode to the deposition capacity per unit area of ​​the cathode (intercalation capacity per unit area of ​​the cathode / deposition capacity per unit area of ​​the cathode) may be, for example, 0.5 to 0.7, 0.53 to 0.66, or 0.54 to 0.66. By satisfying the above ranges for the ratio of the intercalation capacity per unit area of ​​the cathode to the deposition capacity per unit area of ​​the cathode according to one embodiment of the present disclosure, lithium deposition outside the cathode active material layer (220) can be prevented. As a result, the lifespan characteristics of the lithium secondary battery (10) can be improved.

[0085] According to one embodiment of the present disclosure, the N / P ratio of the lithium secondary battery (1) may be, for example, 1 to 1.5, 1 to 1.3, or 1 to 1.2. According to one embodiment of the present disclosure, the N / P ratio may be, for example, 1.1 to 1.5, 1.1 to 1.3, or 1.15 to 1.2. By satisfying the above ranges for the N / P ratio according to one embodiment of the present disclosure, lithium dendrite formation may be suppressed. By satisfying the above ranges for the N / P ratio according to one embodiment of the present disclosure, the lifespan characteristics of the lithium secondary battery (10) may be improved.

[0086] A negative electrode (200) according to one embodiment of the present disclosure may be a prelithiated negative electrode in which lithium ions are intercalated in a negative electrode active material layer (220). Here, prelithiation refers to a process of intercalating a certain amount of lithium ions in advance into a negative electrode active material during the manufacturing process of a lithium secondary battery (10).

[0087] Meanwhile, in the present disclosure, pre-lithiation may include, but is not limited to, physicochemical methods or electrochemical methods, and may be performed through any suitable method that can be implemented by a person skilled in the art. For example, a physicochemical method may include a method of placing a lithium foil layer between a negative electrode current collector and a negative electrode active material layer and then rolling it. For example, when pre-lithiation is performed by an electrochemical method, a pre-lithiated negative electrode can be manufactured by reversibly intercalating lithium ions into the negative electrode (200) by applying a current corresponding to a set pre-lithiation capacity using lithium metal as the counter electrode after manufacturing the negative electrode (200).

[0088] According to one embodiment of the present disclosure, the ratio of the pre-lithiation capacity per unit area of ​​the cathode (200) to the capacity per unit area of ​​the cathode may be 0.1 to 0.3, 0.1 to 0.15, or 0.11 to 0.13. The lifespan characteristics of the lithium secondary battery (10) may be improved by satisfying the above ranges for the ratio of the pre-lithiation capacity per unit area of ​​the cathode (200) to the capacity per unit area of ​​the cathode.

[0089] According to one embodiment of the present disclosure, the prelithiation compensation ratio of a lithium secondary battery (10) calculated by the following mathematical formula 3 may be 1.0 to 1.07, 1.01 to 1.05, or 1.02 to 1.04.

[0090] <Mathematical Formula 3>

[0091] Prelithiation compensation ratio = (Capacity per unit area of ​​the cathode - Prelithiation capacity per unit area of ​​the cathode) / Capacity per unit area of ​​the anode

[0092] The pre-lithiation correction ratio can serve as an indicator to improve performance and stability by precisely adjusting the capacity ratio between the negative electrode and the positive electrode by considering the value of the negative electrode capacity adjusted through the pre-lithiation process when designing the lithium secondary battery (10). If the pre-lithiation correction ratio of the lithium secondary battery (10) according to one embodiment of the present disclosure is less than the above range, dendrites may be formed on the surface of the negative electrode active material layer (220), and the lifespan characteristics may be degraded. If the pre-lithiation correction ratio exceeds the above range, the thickness of the negative electrode active material layer (220) increases, and the resistance of the negative electrode active material layer (220) increases, and the lifespan characteristics may be degraded.

[0093] electrolyte layer (300)

[0094] The electrolyte layer (300) according to one embodiment may include a liquid electrolyte and / or a solid electrolyte.

[0095] The above liquid electrolyte may be an electrolyte for a lithium secondary battery.

[0096] The electrolyte for a lithium secondary battery may include a non-aqueous organic solvent and a lithium salt.

[0097] The above-mentioned non-aqueous organic solvent can serve as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0098] The above-mentioned non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof.

[0099] The above carbonate-based solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc.

[0100] Ester-based solvents such as methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methylpropionate, ethylpropionate, decanolide, mevalonolactone, valerolactone, and caprolactone may be used.

[0101] As ether-based solvents, dibutyl ether, tetraglame, diglame, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. may be used. Additionally, as ketone-based solvents, cyclohexanone, etc. may be used. As alcohol-based solvents, ethyl alcohol, isopropyl alcohol, etc. may be used, and as aprotic solvents, nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, an aromatic ring, or an ether group); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane, 1,4-dioxolane; sulfolanes, etc. may be used.

[0102] The above-mentioned non-aqueous organic solvent can be used alone or in a mixture of two or more types.

[0103] In addition, when using a carbonate-based solvent, a mixture of cyclic carbonates and chain carbonates can be used, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio of 1:1 to 1:9.

[0104] The above lithium salt is a substance that dissolves in an organic solvent and acts as a source of lithium ions within the battery, enabling the basic operation of a lithium secondary battery and facilitating the movement of lithium ions between the anode and cathode. Representative examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1It may include one or more selected from SO2)(x and y are integers from 1 to 20), lithium trifluoromethane sulfonate, lithium tetrafluoroethane sulfonate, lithium difluoro(oxalate)borate (LiDFOB), lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0105] Depending on the type of lithium secondary battery, a separator (not shown) may be present between the positive electrode (100) and the negative electrode (200). As such a separator (not shown), polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used, and of course, a mixed multilayer film such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0106] A separator (not shown) may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0107] The porous substrate may be a polymer membrane formed from any one of the following: polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacetal; polyamide; polyimide; polycarbonate; polyetherketone; polyaryletherketone; polyetherimide; polyamideimide; polybenzimidazole; polyethersulfone; polyphenylene oxide; cyclic olefin copolymer; polyphenylene sulfide; polyethylene naphthalate; glass fiber; Teflon; and polytetrafluoroethylene, or a copolymer or mixture of two or more of these.

[0108] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0109] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include, but is not limited to, inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0110] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0111] The above solid electrolyte may be a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics. When the electrolyte layer includes a solid electrolyte, the lithium secondary battery (10) according to the present disclosure may be an all-solid-state battery.

[0112] Sulfide-based solid electrolytes are, for example, Li3PO4-Li2SO4, Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (In the above formula, m and n are positive numbers, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (In the above formula, p and q are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, and In), Li + 12-n-x A n+ X 2- 6-x Y - x(In the above formula, A is one of P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, or Ta, X is one of S, Se, or Te, Y is Cl, Br, I, F, CN, OCN, SCN, or N3, and 1≤n≤5, 0≤x≤2) Li 7-m-n M m PS 6-n X n (In the above formula, M is one of Na, K, Fe, Mg, Ca, Ag, Cu, Zr, Zn, Sc, Y, Ti, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Mn, Tc, Re, Bh, Ru, Os, Hs, Co, Rh, Ir, Mt, Ni, Pd, Pt, Ds, Au, Rg, Cd, Hg, or Cn, X is one of F, Cl, Br, or I, 0≤m≤2, 0≤n≤2), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), Li 7-x PS 6-x I x It may include (0≤x≤2) or a combination thereof.

[0113] Sulfide-based solid electrolytes can be manufactured by processing starting materials, such as Li2S or P2S5, using methods such as melt quenching or mechanical milling. Additionally, heat treatment may be performed after such processing. Sulfide-based solid electrolytes may be amorphous, crystalline, or a mixture thereof. Sulfide-based solid electrolytes may, for example, contain at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements. Sulfide-based solid electrolytes may, for example, contain Li2S-P2S5. When using a material containing Li2S-P2S5 as a sulfide-based solid electrolyte, the molar ratio of Li2S and P2S5 is, for example, in the range of Li2S : P2S5 = 20 : 80 to 90 : 10, 25 : 75 to 90 : 10, 30 : 70 to 70 : 30, and 40 : 60 to 60 : 40.

[0114] The sulfide-based solid electrolyte may be, for example, an argyrodite-type solid electrolyte. The density of the argyrodite-type solid electrolyte may be 1.5 to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or higher, the internal resistance of the all-solid-state battery is reduced, and penetration of the solid electrolyte separator by lithium can be suppressed more effectively.

[0115] The creative idea is explained in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the creative idea and do not limit the scope of the creative idea to these examples alone.

[0116] Example 1

[0117] (Cathode manufacturing)

[0118] 100 cm of 10 µm thick copper (Cu) foil 2 I prepared (10 cm × 10 cm).

[0119] Hard carbon has an intercalation capacity of 1.2 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.25 mAh / cm² per unit area of ​​the cathode. 2 The mixture was prepared by adding the conductive material (Super-P) and binder (SBR) at 2 wt% each of the total mixture, out of 100 wt%.

[0120] A negative electrode active material slurry was prepared by mixing the mixture with a solvent (deionized water).

[0121] A pre-lithiated cathode was fabricated by coating the prepared slurry onto a prepared copper foil using a doctor blade and drying it at 90°C for 2 hours to remove the solvent.

[0122] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.4 mAh / cm² 2 Charging was carried out until it reached 40 mAh, and then the lithium metal was removed (40 mAh charge).

[0123] (Anode manufacturing)

[0124] 100 cm of 10 µm thick aluminum (Al) foil 2 I prepared (10 cm × 10 cm).

[0125] A cathode active material slurry was prepared by mixing LiCoO2 powder, a carbon conductive material (Super-P), and a binder (PVDF) and dispersing them in a solvent (N-methylpyrrolidone). The LiCoO2 powder has a cathode capacity of 3 mAh / cm² per unit area. 2 It was added to the extent of (1.622 g). The conductive material and binder were added to the extent of 2 wt% each in the total 100 wt% of the cathode active material slurry.

[0126] The manufactured slurry was coated onto a prepared aluminum foil using a doctor blade, dried under reduced pressure at 120°C, and then rolled with a roll press to produce a sheet-shaped anode.

[0127] (Coin cell manufacturing)

[0128] A coin cell was manufactured by placing a polypropylene separator between the cathode and the anode and injecting an electrolyte. As the electrolyte, a solution of 1.15 M LiPF6 dissolved in EC (ethylene carbonate) + EMC (ethyl methyl carbonate) + DMC (dimethyl carbonate) (2:4:4 volume ratio) was used.

[0129] Example 2

[0130] When manufacturing the cathode, hard carbon has an intercalation capacity of 1.4 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.461 mAh / cm² per unit area of ​​the cathode. 2 It was input to make it so,

[0131] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.5 mAh / cm² 2 We proceeded with charging until it became,

[0132] When manufacturing the cathode, LiCoO2 powder has a capacity per unit area of ​​3.3 mAh / cm² 2 A coin cell was prepared in the same manner as in Example 1, except that the amount added was (1.784 g).

[0133] Example 3

[0134] When manufacturing the cathode, hard carbon has an intercalation capacity of 1.4 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.11 mAh / cm² per unit area of ​​the cathode. 2 It was input to make it so,

[0135] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.4 mAh / cm² 2 We proceeded with charging until it became,

[0136] When manufacturing the cathode, LiCoO2 powder has a capacity of 3 mAh / cm² per unit area of ​​the cathode. 2 A coin cell was prepared in the same manner as in Example 1, except that the amount added was 1.622 g.

[0137] Example 4

[0138] When manufacturing the cathode, hard carbon has an intercalation capacity of 1.6 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.96 mAh / cm² per unit area of ​​the cathode. 2 It was input to make it so,

[0139] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.6 mAh / cm² 2 We proceeded with charging until it became,

[0140] When manufacturing the cathode, LiCoO2 powder has a capacity per unit area of ​​3.8 mAh / cm² 2 A coin cell was prepared in the same manner as in Example 1, except that the amount added was (2.054 g).

[0141] Comparative Example 1

[0142] When manufacturing the cathode, hard carbon has an intercalation capacity of 1.8 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.9 mAh / cm² per unit area of ​​the cathode. 2 It was input to make it so,

[0143] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.4 mAh / cm² 2 We proceeded with charging until it became,

[0144] When manufacturing the cathode, LiCoO2 powder has a capacity per unit area of ​​3.5 mAh / cm² 2 A coin cell was prepared in the same manner as in Example 1, except that the amount added was 1.892 g.

[0145] Comparative Example 2

[0146] When manufacturing the cathode, hard carbon has an intercalation capacity of 1.2 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.595 mAh / cm² per unit area of ​​the cathode. 2 It was input to make it so,

[0147] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.6 mAh / cm² 2 We proceeded with charging until it became,

[0148] When manufacturing the cathode, LiCoO2 powder has a capacity per unit area of ​​3.3 mAh / cm² 2 A coin cell was prepared in the same manner as in Example 1, except that the amount added was (1.784 g).

[0149] Comparative Example 3

[0150] When manufacturing the cathode, hard carbon has an intercalation capacity of 1.2 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.25 mAh / cm² per unit area of ​​the cathode. 2 It was input to make it so,

[0151] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.2 mAh / cm² 2 We proceeded with charging until it became,

[0152] When manufacturing the cathode, LiCoO2 powder has a capacity of 3 mAh / cm² per unit area of ​​the cathode. 2 A coin cell was prepared in the same manner as in Example 1, except that the amount added was 1.622 g.

[0153] Comparative Example 4

[0154] When manufacturing the cathode, hard carbon has an intercalation capacity of 1.6 mAh / cm² per unit area of ​​the cathode. 2 Hard carbon and silver nanoparticles (Ag) were added to achieve a deposition capacity of 2.25 mAh / cm² per unit area of ​​the cathode. 2 It was input to make it so,

[0155] Prior to pre-lithiation, lithium metal was connected to the negative electrode as the counter electrode and charging was performed by applying voltage, and the pre-lithiation capacity per unit area of ​​the negative electrode was 0.6 mAh / cm² 2 We proceeded with charging until it became,

[0156] When manufacturing the cathode, LiCoO2 powder has a capacity per unit area of ​​3.5 mAh / cm² 2 A coin cell was prepared in the same manner as in Example 1, except that the amount added was 1.892 g.

[0157] The “capacity per unit area of ​​the positive electrode (AA),” “intercalation capacity per unit area of ​​the negative electrode (BB),” “precipitation capacity per unit area of ​​the negative electrode (CC),” “capacity per unit area of ​​the negative electrode (DD),” and “pre-lithiation capacity per unit area of ​​the negative electrode (EE)” of the lithium secondary batteries prepared in each example and comparative example are summarized in Table 1 below.

[0158] AA * (mAh / cm 2 )BB * (mAh / cm2 )CC * (mAh / cm 2 )DD * (mAh / cm 2 )EE * (mAh / cm 2 Example 1 31.22.253.450.4 Example 23.31.42.4613.8610.5 Example 3 31.42.113.510.4 Example 43.81.62.964.560.6 Comparative Example 13.51.82.94.70.4 Comparative Example 23.31.22.5953.7950.6 Comparative Example 331.22.253.450.2 Comparative Example 43.51.62.253.850.6

[0159] * In Table 1 above, AA: capacity per unit area of ​​the anode, BB: intercalation capacity per unit area of ​​the cathode, CC: deposition capacity per unit area of ​​the cathode, DD: capacity per unit area of ​​the cathode, EE: pre-lithiation capacity per unit area of ​​the cathode. The “ratio of intercalation capacity per unit area of ​​the cathode to capacity per unit area of ​​the anode (BB / AA),” “ratio of intercalation capacity per unit area of ​​the cathode to deposition capacity per unit area of ​​the cathode (BB / CC),” “ratio (DD / AA),” “ratio of pre-lithiation capacity per unit area of ​​the cathode to capacity per unit area of ​​the cathode (EE / DD),” and “pre-lithiation correction ratio ((DD-EE) / AA)” of the lithium secondary batteries prepared in each example and comparative example were calculated according to the definitions disclosed in this specification and summarized in Table 2 below.

[0160] BB / AA ** BB / CC ** DD / AA ** EE / DD ** (DD-EE) / AA **Example 10.40.531.150.121.02 Example 20.420.571.170.131.02 Example 30.470.661.170.111.04 Example 40.420.541.200.131.04 Comparative Example 10.510.621.340.091.23 Comparative Example 20.360.461.150.160.97 Comparative Example 30.400.531.150.061.08 Comparative Example 40.460.711.100.160.93

[0161] ** In Table 2 above, BB / AA: Ratio of the intercalation capacity per unit area of ​​the cathode to the capacity per unit area of ​​the anode, BB / CC: Ratio of the intercalation capacity per unit area of ​​the cathode to the deposition capacity per unit area of ​​the cathode, DD / AA: N / P ratio, EE / DD: Ratio of the pre-lithiation capacity per unit area of ​​the cathode to the capacity per unit area of ​​the cathode, (DD-EE) / AA: Pre-lithiation correction ratio

[0162] evaluation

[0163] The initial efficiency and charge / discharge characteristics of the coin cells manufactured in Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated by the following charge / discharge test.

[0164] The charge / discharge test was performed by placing the coin cell in a 45°C constant temperature bath.

[0165] For the first cycle, the battery was charged at 0.1 C until the battery voltage reached 4.2 V, and discharged at 0.05 C until the battery voltage reached 3.0 V. The charging capacity and discharging capacity in the first cycle were measured, and the initial charging capacity and initial discharging capacity were recorded. The initial efficiency (%) was calculated as (initial discharging capacity / initial charging capacity) × 100 (%) and is shown in Table 3 below.

[0166] Afterwards, the above charge-discharge test was repeated 300 times. SOH was measured after each cycle, and the number of cycles repeated until the SOH reached 80% was shown as the life characteristics in Table 3 below.

[0167] Initial Efficiency (%) Lifetime Characteristics (@SOH 80%, cycles) Example 1 89.9222 Example 2 90.5247 Example 3 89.5245 Example 4 90.0242 Comparative Example 188.5148 Comparative Example 289.1177 Comparative Example 388.5157 Comparative Example 488.5181

[0168] In the case of Comparative Examples 1 and 3, where the pre-lithiation correction ratio ((DD-EE) / AA) was 1.08 or higher, the initial efficiency and lifespan characteristics were relatively poor compared to Examples 1 to 4. Meanwhile, Comparative Examples 2 and 4, where the pre-lithiation correction ratio was less than 1.0, also showed poorer initial efficiency and lifespan characteristics than Examples 1 to 4.

[0169] On the other hand, it was confirmed that the initial efficiency and lifespan characteristics were improved in the coin cells fabricated in Examples 1 to 4, in which the pre-lithiation correction ratio had a value between 1.0 and 1.07.

[0170] Although an exemplary embodiment has been described in detail above with reference to the attached drawings, the present creative idea is not limited to such examples. It is obvious that a person skilled in the art to which the present creative idea belongs can derive various variations or modifications within the scope of the technical idea described in the patent claims, and these also naturally fall within the technical scope of the present creative idea.

Claims

1. A positive electrode comprising a positive current collector and a positive active material layer on the positive current collector; A cathode comprising a cathode current collector and a cathode active material layer on the cathode current collector; and It includes an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer; The above cathode intercalates lithium by charging, and The above cathode plating lithium upon charging, The above cathode is a prelithiated cathode in which lithium ions are intercalated in the cathode active material layer, and A lithium secondary battery having a prelithiation compensation ratio calculated by the following mathematical formula 3 that is 1.0 to 1.07: <Mathematical Formula 3> Prelithiation compensation ratio = (Capacity per unit area of ​​the cathode - Prelithiation capacity per unit area of ​​the cathode) / Capacity per unit area of ​​the anode.

2. In Paragraph 1, The above-described cathode is a lithium secondary battery capable of realizing a reversible capacity for both the intercalated lithium and the precipitated lithium.

3. In Paragraph 1, A lithium secondary battery having a prelithiation compensation ratio calculated by the following mathematical formula 3 that is 1.01 to 1.05: <Mathematical Formula 3> Prelithiation compensation ratio = (Capacity per unit area of ​​the cathode - Prelithiation capacity per unit area of ​​the cathode) / Capacity per unit area of ​​the anode.

4. In Paragraph 1, A lithium secondary battery in which the ratio of the pre-lithiation capacity per unit area of ​​the cathode to the capacity per unit area of ​​the cathode is 0.1 to 0.

3.

5. In Paragraph 1, A lithium secondary battery in which the ratio of the pre-lithiation capacity per unit area of ​​the cathode to the capacity per unit area of ​​the cathode is 0.1 to 0.

15.

6. In Paragraph 1, A lithium secondary battery having an N / P ratio defined as the ratio of the capacity per unit area of ​​the negative electrode to the capacity per unit area of ​​the positive electrode, of 1 to 1.

5.

7. In Paragraph 1, A lithium secondary battery having an N / P ratio defined as the ratio of the capacity per unit area of ​​the negative electrode to the capacity per unit area of ​​the positive electrode, of 1.1 to 1.

3.

8. In Paragraph 1, A lithium secondary battery in which the ratio of the intercalation capacity per unit area of ​​the negative electrode to the deposition capacity per unit area of ​​the negative electrode is 0.5 to 0.

7.

9. In Paragraph 1, A lithium secondary battery in which the ratio of the intercalation capacity per unit area of ​​the negative electrode to the deposition capacity per unit area of ​​the negative electrode is 0.53 to 0.

66.

10. In Paragraph 1, A lithium secondary battery in which the capacity per unit area of ​​the positive electrode exceeds the intercalation capacity per unit area of ​​the negative electrode.

11. In Paragraph 1, A lithium secondary battery in which the ratio of the intercalation capacity per unit area of ​​the negative electrode to the capacity per unit area of ​​the positive electrode is 0.38 to 0.

5.

12. In Paragraph 1, A lithium secondary battery in which the ratio of the intercalation capacity per unit area of ​​the negative electrode to the capacity per unit area of ​​the positive electrode is 0.42 to 0.

47.

13. In Paragraph 1, The above negative electrode active material layer includes a negative electrode active material, and The above negative electrode active material comprises a carbon-based negative electrode active material, in a lithium secondary battery.

14. In Paragraph 13, The above carbon-based negative electrode active material comprises amorphous carbon, in a lithium secondary battery.

15. In Paragraph 13, A lithium secondary battery, wherein the above-mentioned negative electrode active material layer further comprises a lithium-affinity metal.

16. In Paragraph 15, A lithium secondary battery comprising at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), or zinc (Zn), or any combination thereof.

17. In Paragraph 15, The above lithium-affinity metal is a lithium-affinity metal particle, and A lithium secondary battery having an average particle size of the lithium-affinity metal particles of the above-mentioned amount of 10 nm to 4 μm.

18. In Paragraph 1, A lithium secondary battery comprising the above positive active material, a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

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